2 * pcap-linux.c: Packet capture interface to the Linux kernel
4 * Copyright (c) 2000 Torsten Landschoff <torsten@debian.org>
5 * Sebastian Krahmer <krahmer@cs.uni-potsdam.de>
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
19 * 3. The names of the authors may not be used to endorse or promote
20 * products derived from this software without specific prior
23 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
25 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
27 * Modifications: Added PACKET_MMAP support
28 * Paolo Abeni <paolo.abeni@email.it>
29 * Added TPACKET_V3 support
30 * Gabor Tatarka <gabor.tatarka@ericsson.com>
32 * based on previous works of:
33 * Simon Patarin <patarin@cs.unibo.it>
34 * Phil Wood <cpw@lanl.gov>
36 * Monitor-mode support for mac80211 includes code taken from the iw
37 * command; the copyright notice for that code is
39 * Copyright (c) 2007, 2008 Johannes Berg
40 * Copyright (c) 2007 Andy Lutomirski
41 * Copyright (c) 2007 Mike Kershaw
42 * Copyright (c) 2008 Gábor Stefanik
44 * All rights reserved.
46 * Redistribution and use in source and binary forms, with or without
47 * modification, are permitted provided that the following conditions
49 * 1. Redistributions of source code must retain the above copyright
50 * notice, this list of conditions and the following disclaimer.
51 * 2. Redistributions in binary form must reproduce the above copyright
52 * notice, this list of conditions and the following disclaimer in the
53 * documentation and/or other materials provided with the distribution.
54 * 3. The name of the author may not be used to endorse or promote products
55 * derived from this software without specific prior written permission.
57 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
58 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
59 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
60 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
61 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
62 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
63 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
64 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
65 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
66 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
71 * Known problems with 2.0[.x] kernels:
73 * - The loopback device gives every packet twice; on 2.2[.x] kernels,
74 * if we use PF_PACKET, we can filter out the transmitted version
75 * of the packet by using data in the "sockaddr_ll" returned by
76 * "recvfrom()", but, on 2.0[.x] kernels, we have to use
77 * PF_INET/SOCK_PACKET, which means "recvfrom()" supplies a
78 * "sockaddr_pkt" which doesn't give us enough information to let
81 * - We have to set the interface's IFF_PROMISC flag ourselves, if
82 * we're to run in promiscuous mode, which means we have to turn
83 * it off ourselves when we're done; the kernel doesn't keep track
84 * of how many sockets are listening promiscuously, which means
85 * it won't get turned off automatically when no sockets are
86 * listening promiscuously. We catch "pcap_close()" and, for
87 * interfaces we put into promiscuous mode, take them out of
88 * promiscuous mode - which isn't necessarily the right thing to
89 * do, if another socket also requested promiscuous mode between
90 * the time when we opened the socket and the time when we close
93 * - MSG_TRUNC isn't supported, so you can't specify that "recvfrom()"
94 * return the amount of data that you could have read, rather than
95 * the amount that was returned, so we can't just allocate a buffer
96 * whose size is the snapshot length and pass the snapshot length
97 * as the byte count, and also pass MSG_TRUNC, so that the return
98 * value tells us how long the packet was on the wire.
100 * This means that, if we want to get the actual size of the packet,
101 * so we can return it in the "len" field of the packet header,
102 * we have to read the entire packet, not just the part that fits
103 * within the snapshot length, and thus waste CPU time copying data
104 * from the kernel that our caller won't see.
106 * We have to get the actual size, and supply it in "len", because
107 * otherwise, the IP dissector in tcpdump, for example, will complain
108 * about "truncated-ip", as the packet will appear to have been
109 * shorter, on the wire, than the IP header said it should have been.
127 #include <sys/stat.h>
128 #include <sys/socket.h>
129 #include <sys/ioctl.h>
130 #include <sys/utsname.h>
131 #include <sys/mman.h>
132 #include <linux/if.h>
133 #include <linux/if_packet.h>
134 #include <linux/sockios.h>
135 #include <netinet/in.h>
136 #include <linux/if_ether.h>
137 #include <net/if_arp.h>
141 #include "pcap-int.h"
142 #include "pcap/sll.h"
143 #include "pcap/vlan.h"
146 * If PF_PACKET is defined, we can use {SOCK_RAW,SOCK_DGRAM}/PF_PACKET
147 * sockets rather than SOCK_PACKET sockets.
149 * To use them, we include <linux/if_packet.h> rather than
150 * <netpacket/packet.h>; we do so because
152 * some Linux distributions (e.g., Slackware 4.0) have 2.2 or
153 * later kernels and libc5, and don't provide a <netpacket/packet.h>
156 * not all versions of glibc2 have a <netpacket/packet.h> file
157 * that defines stuff needed for some of the 2.4-or-later-kernel
158 * features, so if the system has a 2.4 or later kernel, we
159 * still can't use those features.
161 * We're already including a number of other <linux/XXX.h> headers, and
162 * this code is Linux-specific (no other OS has PF_PACKET sockets as
163 * a raw packet capture mechanism), so it's not as if you gain any
164 * useful portability by using <netpacket/packet.h>
166 * XXX - should we just include <linux/if_packet.h> even if PF_PACKET
167 * isn't defined? It only defines one data structure in 2.0.x, so
168 * it shouldn't cause any problems.
171 # include <linux/if_packet.h>
174 * On at least some Linux distributions (for example, Red Hat 5.2),
175 * there's no <netpacket/packet.h> file, but PF_PACKET is defined if
176 * you include <sys/socket.h>, but <linux/if_packet.h> doesn't define
177 * any of the PF_PACKET stuff such as "struct sockaddr_ll" or any of
178 * the PACKET_xxx stuff.
180 * So we check whether PACKET_HOST is defined, and assume that we have
181 * PF_PACKET sockets only if it is defined.
184 # define HAVE_PF_PACKET_SOCKETS
185 # ifdef PACKET_AUXDATA
186 # define HAVE_PACKET_AUXDATA
187 # endif /* PACKET_AUXDATA */
188 # endif /* PACKET_HOST */
191 /* check for memory mapped access avaibility. We assume every needed
192 * struct is defined if the macro TPACKET_HDRLEN is defined, because it
193 * uses many ring related structs and macros */
194 # ifdef PCAP_SUPPORT_PACKET_RING
195 # ifdef TPACKET_HDRLEN
196 # define HAVE_PACKET_RING
197 # ifdef TPACKET3_HDRLEN
198 # define HAVE_TPACKET3
199 # endif /* TPACKET3_HDRLEN */
200 # ifdef TPACKET2_HDRLEN
201 # define HAVE_TPACKET2
202 # else /* TPACKET2_HDRLEN */
203 # define TPACKET_V1 0 /* Old kernel with only V1, so no TPACKET_Vn defined */
204 # endif /* TPACKET2_HDRLEN */
205 # endif /* TPACKET_HDRLEN */
206 # endif /* PCAP_SUPPORT_PACKET_RING */
207 #endif /* PF_PACKET */
209 #ifdef SO_ATTACH_FILTER
210 #include <linux/types.h>
211 #include <linux/filter.h>
214 #ifdef HAVE_LINUX_NET_TSTAMP_H
215 #include <linux/net_tstamp.h>
218 #ifdef HAVE_LINUX_SOCKIOS_H
219 #include <linux/sockios.h>
222 #ifdef HAVE_LINUX_IF_BONDING_H
223 #include <linux/if_bonding.h>
226 * The ioctl code to use to check whether a device is a bonding device.
228 #if defined(SIOCBONDINFOQUERY)
229 #define BOND_INFO_QUERY_IOCTL SIOCBONDINFOQUERY
230 #elif defined(BOND_INFO_QUERY_OLD)
231 #define BOND_INFO_QUERY_IOCTL BOND_INFO_QUERY_OLD
233 #endif /* HAVE_LINUX_IF_BONDING_H */
236 * Got Wireless Extensions?
238 #ifdef HAVE_LINUX_WIRELESS_H
239 #include <linux/wireless.h>
240 #endif /* HAVE_LINUX_WIRELESS_H */
246 #include <linux/nl80211.h>
248 #include <netlink/genl/genl.h>
249 #include <netlink/genl/family.h>
250 #include <netlink/genl/ctrl.h>
251 #include <netlink/msg.h>
252 #include <netlink/attr.h>
253 #endif /* HAVE_LIBNL */
256 * Got ethtool support?
258 #ifdef HAVE_LINUX_ETHTOOL_H
259 #include <linux/ethtool.h>
262 #ifndef HAVE_SOCKLEN_T
263 typedef int socklen_t;
268 * This is being compiled on a system that lacks MSG_TRUNC; define it
269 * with the value it has in the 2.2 and later kernels, so that, on
270 * those kernels, when we pass it in the flags argument to "recvfrom()"
271 * we're passing the right value and thus get the MSG_TRUNC behavior
272 * we want. (We don't get that behavior on 2.0[.x] kernels, because
273 * they didn't support MSG_TRUNC.)
275 #define MSG_TRUNC 0x20
280 * This is being compiled on a system that lacks SOL_PACKET; define it
281 * with the value it has in the 2.2 and later kernels, so that we can
282 * set promiscuous mode in the good modern way rather than the old
283 * 2.0-kernel crappy way.
285 #define SOL_PACKET 263
288 #define MAX_LINKHEADER_SIZE 256
291 * When capturing on all interfaces we use this as the buffer size.
292 * Should be bigger then all MTUs that occur in real life.
293 * 64kB should be enough for now.
295 #define BIGGER_THAN_ALL_MTUS (64*1024)
298 * Private data for capturing on Linux SOCK_PACKET or PF_PACKET sockets.
301 u_int packets_read; /* count of packets read with recvfrom() */
302 long proc_dropped; /* packets reported dropped by /proc/net/dev */
303 struct pcap_stat stat;
305 char *device; /* device name */
306 int filter_in_userland; /* must filter in userland */
307 int blocks_to_filter_in_userland;
308 int must_do_on_close; /* stuff we must do when we close */
309 int timeout; /* timeout for buffering */
310 int sock_packet; /* using Linux 2.0 compatible interface */
311 int cooked; /* using SOCK_DGRAM rather than SOCK_RAW */
312 int ifindex; /* interface index of device we're bound to */
313 int lo_ifindex; /* interface index of the loopback device */
314 bpf_u_int32 oldmode; /* mode to restore when turning monitor mode off */
315 char *mondevice; /* mac80211 monitor device we created */
316 u_char *mmapbuf; /* memory-mapped region pointer */
317 size_t mmapbuflen; /* size of region */
318 int vlan_offset; /* offset at which to insert vlan tags; if -1, don't insert */
319 u_int tp_version; /* version of tpacket_hdr for mmaped ring */
320 u_int tp_hdrlen; /* hdrlen of tpacket_hdr for mmaped ring */
321 u_char *oneshot_buffer; /* buffer for copy of packet */
322 int poll_timeout; /* timeout to use in poll() */
324 unsigned char *current_packet; /* Current packet within the TPACKET_V3 block. Move to next block if NULL. */
325 int packets_left; /* Unhandled packets left within the block from previous call to pcap_read_linux_mmap_v3 in case of TPACKET_V3. */
330 * Stuff to do when we close.
332 #define MUST_CLEAR_PROMISC 0x00000001 /* clear promiscuous mode */
333 #define MUST_CLEAR_RFMON 0x00000002 /* clear rfmon (monitor) mode */
334 #define MUST_DELETE_MONIF 0x00000004 /* delete monitor-mode interface */
337 * Prototypes for internal functions and methods.
339 static int get_if_flags(const char *, bpf_u_int32 *, char *);
340 static int is_wifi(int, const char *);
341 static void map_arphrd_to_dlt(pcap_t *, int, int, const char *, int);
342 #ifdef HAVE_PF_PACKET_SOCKETS
343 static short int map_packet_type_to_sll_type(short int);
345 static int pcap_activate_linux(pcap_t *);
346 static int activate_old(pcap_t *);
347 static int activate_new(pcap_t *);
348 static int activate_mmap(pcap_t *, int *);
349 static int pcap_can_set_rfmon_linux(pcap_t *);
350 static int pcap_read_linux(pcap_t *, int, pcap_handler, u_char *);
351 static int pcap_read_packet(pcap_t *, pcap_handler, u_char *);
352 static int pcap_inject_linux(pcap_t *, const void *, size_t);
353 static int pcap_stats_linux(pcap_t *, struct pcap_stat *);
354 static int pcap_setfilter_linux(pcap_t *, struct bpf_program *);
355 static int pcap_setdirection_linux(pcap_t *, pcap_direction_t);
356 static int pcap_set_datalink_linux(pcap_t *, int);
357 static void pcap_cleanup_linux(pcap_t *);
360 * This is what the header structure looks like in a 64-bit kernel;
361 * we use this, rather than struct tpacket_hdr, if we're using
362 * TPACKET_V1 in 32-bit code running on a 64-bit kernel.
364 struct tpacket_hdr_64 {
367 unsigned int tp_snaplen;
368 unsigned short tp_mac;
369 unsigned short tp_net;
371 unsigned int tp_usec;
375 * We use this internally as the tpacket version for TPACKET_V1 in
376 * 32-bit code on a 64-bit kernel.
378 #define TPACKET_V1_64 99
381 struct tpacket_hdr *h1;
382 struct tpacket_hdr_64 *h1_64;
384 struct tpacket2_hdr *h2;
387 struct tpacket_block_desc *h3;
392 #ifdef HAVE_PACKET_RING
393 #define RING_GET_FRAME_AT(h, offset) (((union thdr **)h->buffer)[(offset)])
394 #define RING_GET_CURRENT_FRAME(h) RING_GET_FRAME_AT(h, h->offset)
396 static void destroy_ring(pcap_t *handle);
397 static int create_ring(pcap_t *handle, int *status);
398 static int prepare_tpacket_socket(pcap_t *handle);
399 static void pcap_cleanup_linux_mmap(pcap_t *);
400 static int pcap_read_linux_mmap_v1(pcap_t *, int, pcap_handler , u_char *);
401 static int pcap_read_linux_mmap_v1_64(pcap_t *, int, pcap_handler , u_char *);
403 static int pcap_read_linux_mmap_v2(pcap_t *, int, pcap_handler , u_char *);
406 static int pcap_read_linux_mmap_v3(pcap_t *, int, pcap_handler , u_char *);
408 static int pcap_setfilter_linux_mmap(pcap_t *, struct bpf_program *);
409 static int pcap_setnonblock_mmap(pcap_t *p, int nonblock);
410 static int pcap_getnonblock_mmap(pcap_t *p);
411 static void pcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h,
412 const u_char *bytes);
416 * In pre-3.0 kernels, the tp_vlan_tci field is set to whatever the
417 * vlan_tci field in the skbuff is. 0 can either mean "not on a VLAN"
418 * or "on VLAN 0". There is no flag set in the tp_status field to
419 * distinguish between them.
421 * In 3.0 and later kernels, if there's a VLAN tag present, the tp_vlan_tci
422 * field is set to the VLAN tag, and the TP_STATUS_VLAN_VALID flag is set
423 * in the tp_status field, otherwise the tp_vlan_tci field is set to 0 and
424 * the TP_STATUS_VLAN_VALID flag isn't set in the tp_status field.
426 * With a pre-3.0 kernel, we cannot distinguish between packets with no
427 * VLAN tag and packets on VLAN 0, so we will mishandle some packets, and
428 * there's nothing we can do about that.
430 * So, on those systems, which never set the TP_STATUS_VLAN_VALID flag, we
431 * continue the behavior of earlier libpcaps, wherein we treated packets
432 * with a VLAN tag of 0 as being packets without a VLAN tag rather than packets
433 * on VLAN 0. We do this by treating packets with a tp_vlan_tci of 0 and
434 * with the TP_STATUS_VLAN_VALID flag not set in tp_status as not having
435 * VLAN tags. This does the right thing on 3.0 and later kernels, and
436 * continues the old unfixably-imperfect behavior on pre-3.0 kernels.
438 * If TP_STATUS_VLAN_VALID isn't defined, we test it as the 0x10 bit; it
439 * has that value in 3.0 and later kernels.
441 #ifdef TP_STATUS_VLAN_VALID
442 #define VLAN_VALID(hdr, hv) ((hv)->tp_vlan_tci != 0 || ((hdr)->tp_status & TP_STATUS_VLAN_VALID))
445 * This is being compiled on a system that lacks TP_STATUS_VLAN_VALID,
446 * so we testwith the value it has in the 3.0 and later kernels, so
447 * we can test it if we're running on a system that has it. (If we're
448 * running on a system that doesn't have it, it won't be set in the
449 * tp_status field, so the tests of it will always fail; that means
450 * we behave the way we did before we introduced this macro.)
452 #define VLAN_VALID(hdr, hv) ((hv)->tp_vlan_tci != 0 || ((hdr)->tp_status & 0x10))
455 #ifdef TP_STATUS_VLAN_TPID_VALID
456 # define VLAN_TPID(hdr, hv) (((hv)->tp_vlan_tpid || ((hdr)->tp_status & TP_STATUS_VLAN_TPID_VALID)) ? (hv)->tp_vlan_tpid : ETH_P_8021Q)
458 # define VLAN_TPID(hdr, hv) ETH_P_8021Q
462 * Wrap some ioctl calls
464 #ifdef HAVE_PF_PACKET_SOCKETS
465 static int iface_get_id(int fd, const char *device, char *ebuf);
466 #endif /* HAVE_PF_PACKET_SOCKETS */
467 static int iface_get_mtu(int fd, const char *device, char *ebuf);
468 static int iface_get_arptype(int fd, const char *device, char *ebuf);
469 #ifdef HAVE_PF_PACKET_SOCKETS
470 static int iface_bind(int fd, int ifindex, char *ebuf, int protocol);
471 #ifdef IW_MODE_MONITOR
472 static int has_wext(int sock_fd, const char *device, char *ebuf);
473 #endif /* IW_MODE_MONITOR */
474 static int enter_rfmon_mode(pcap_t *handle, int sock_fd,
476 #endif /* HAVE_PF_PACKET_SOCKETS */
477 #if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
478 static int iface_ethtool_get_ts_info(const char *device, pcap_t *handle,
481 #ifdef HAVE_PACKET_RING
482 static int iface_get_offload(pcap_t *handle);
484 static int iface_bind_old(int fd, const char *device, char *ebuf);
486 #ifdef SO_ATTACH_FILTER
487 static int fix_program(pcap_t *handle, struct sock_fprog *fcode,
489 static int fix_offset(struct bpf_insn *p);
490 static int set_kernel_filter(pcap_t *handle, struct sock_fprog *fcode);
491 static int reset_kernel_filter(pcap_t *handle);
493 static struct sock_filter total_insn
494 = BPF_STMT(BPF_RET | BPF_K, 0);
495 static struct sock_fprog total_fcode
496 = { 1, &total_insn };
497 #endif /* SO_ATTACH_FILTER */
500 pcap_create_interface(const char *device, char *ebuf)
504 handle = pcap_create_common(ebuf, sizeof (struct pcap_linux));
508 handle->activate_op = pcap_activate_linux;
509 handle->can_set_rfmon_op = pcap_can_set_rfmon_linux;
511 #if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
513 * See what time stamp types we support.
515 if (iface_ethtool_get_ts_info(device, handle, ebuf) == -1) {
521 #if defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS)
523 * We claim that we support microsecond and nanosecond time
526 * XXX - with adapter-supplied time stamps, can we choose
527 * microsecond or nanosecond time stamps on arbitrary
530 handle->tstamp_precision_count = 2;
531 handle->tstamp_precision_list = malloc(2 * sizeof(u_int));
532 if (handle->tstamp_precision_list == NULL) {
533 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
538 handle->tstamp_precision_list[0] = PCAP_TSTAMP_PRECISION_MICRO;
539 handle->tstamp_precision_list[1] = PCAP_TSTAMP_PRECISION_NANO;
540 #endif /* defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS) */
547 * If interface {if} is a mac80211 driver, the file
548 * /sys/class/net/{if}/phy80211 is a symlink to
549 * /sys/class/ieee80211/{phydev}, for some {phydev}.
551 * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at
552 * least, has a "wmaster0" device and a "wlan0" device; the
553 * latter is the one with the IP address. Both show up in
554 * "tcpdump -D" output. Capturing on the wmaster0 device
555 * captures with 802.11 headers.
557 * airmon-ng searches through /sys/class/net for devices named
558 * monN, starting with mon0; as soon as one *doesn't* exist,
559 * it chooses that as the monitor device name. If the "iw"
560 * command exists, it does "iw dev {if} interface add {monif}
561 * type monitor", where {monif} is the monitor device. It
562 * then (sigh) sleeps .1 second, and then configures the
563 * device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface
564 * is a file, it writes {mondev}, without a newline, to that file,
565 * and again (sigh) sleeps .1 second, and then iwconfig's that
566 * device into monitor mode and configures it up. Otherwise,
567 * you can't do monitor mode.
569 * All these devices are "glued" together by having the
570 * /sys/class/net/{device}/phy80211 links pointing to the same
571 * place, so, given a wmaster, wlan, or mon device, you can
572 * find the other devices by looking for devices with
573 * the same phy80211 link.
575 * To turn monitor mode off, delete the monitor interface,
576 * either with "iw dev {monif} interface del" or by sending
577 * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface
579 * Note: if you try to create a monitor device named "monN", and
580 * there's already a "monN" device, it fails, as least with
581 * the netlink interface (which is what iw uses), with a return
582 * value of -ENFILE. (Return values are negative errnos.) We
583 * could probably use that to find an unused device.
585 * Yes, you can have multiple monitor devices for a given
590 * Is this a mac80211 device? If so, fill in the physical device path and
591 * return 1; if not, return 0. On an error, fill in handle->errbuf and
595 get_mac80211_phydev(pcap_t *handle, const char *device, char *phydev_path,
596 size_t phydev_max_pathlen)
602 * Generate the path string for the symlink to the physical device.
604 if (asprintf(&pathstr, "/sys/class/net/%s/phy80211", device) == -1) {
605 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
606 "%s: Can't generate path name string for /sys/class/net device",
610 bytes_read = readlink(pathstr, phydev_path, phydev_max_pathlen);
611 if (bytes_read == -1) {
612 if (errno == ENOENT || errno == EINVAL) {
614 * Doesn't exist, or not a symlink; assume that
615 * means it's not a mac80211 device.
620 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
621 errno, "%s: Can't readlink %s", device, pathstr);
626 phydev_path[bytes_read] = '\0';
630 #ifdef HAVE_LIBNL_SOCKETS
631 #define get_nl_errmsg nl_geterror
633 /* libnl 2.x compatibility code */
635 #define nl_sock nl_handle
637 static inline struct nl_handle *
638 nl_socket_alloc(void)
640 return nl_handle_alloc();
644 nl_socket_free(struct nl_handle *h)
646 nl_handle_destroy(h);
649 #define get_nl_errmsg strerror
652 __genl_ctrl_alloc_cache(struct nl_handle *h, struct nl_cache **cache)
654 struct nl_cache *tmp = genl_ctrl_alloc_cache(h);
660 #define genl_ctrl_alloc_cache __genl_ctrl_alloc_cache
661 #endif /* !HAVE_LIBNL_SOCKETS */
663 struct nl80211_state {
664 struct nl_sock *nl_sock;
665 struct nl_cache *nl_cache;
666 struct genl_family *nl80211;
670 nl80211_init(pcap_t *handle, struct nl80211_state *state, const char *device)
674 state->nl_sock = nl_socket_alloc();
675 if (!state->nl_sock) {
676 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
677 "%s: failed to allocate netlink handle", device);
681 if (genl_connect(state->nl_sock)) {
682 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
683 "%s: failed to connect to generic netlink", device);
684 goto out_handle_destroy;
687 err = genl_ctrl_alloc_cache(state->nl_sock, &state->nl_cache);
689 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
690 "%s: failed to allocate generic netlink cache: %s",
691 device, get_nl_errmsg(-err));
692 goto out_handle_destroy;
695 state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211");
696 if (!state->nl80211) {
697 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
698 "%s: nl80211 not found", device);
705 nl_cache_free(state->nl_cache);
707 nl_socket_free(state->nl_sock);
712 nl80211_cleanup(struct nl80211_state *state)
714 genl_family_put(state->nl80211);
715 nl_cache_free(state->nl_cache);
716 nl_socket_free(state->nl_sock);
720 del_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
721 const char *device, const char *mondevice);
724 add_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
725 const char *device, const char *mondevice)
727 struct pcap_linux *handlep = handle->priv;
732 ifindex = iface_get_id(sock_fd, device, handle->errbuf);
738 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
739 "%s: failed to allocate netlink msg", device);
743 genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
744 0, NL80211_CMD_NEW_INTERFACE, 0);
745 NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
746 NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, mondevice);
747 NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, NL80211_IFTYPE_MONITOR);
749 err = nl_send_auto_complete(state->nl_sock, msg);
751 #if defined HAVE_LIBNL_NLE
752 if (err == -NLE_FAILURE) {
754 if (err == -ENFILE) {
757 * Device not available; our caller should just
758 * keep trying. (libnl 2.x maps ENFILE to
759 * NLE_FAILURE; it can also map other errors
760 * to that, but there's not much we can do
767 * Real failure, not just "that device is not
770 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
771 "%s: nl_send_auto_complete failed adding %s interface: %s",
772 device, mondevice, get_nl_errmsg(-err));
777 err = nl_wait_for_ack(state->nl_sock);
779 #if defined HAVE_LIBNL_NLE
780 if (err == -NLE_FAILURE) {
782 if (err == -ENFILE) {
785 * Device not available; our caller should just
786 * keep trying. (libnl 2.x maps ENFILE to
787 * NLE_FAILURE; it can also map other errors
788 * to that, but there's not much we can do
795 * Real failure, not just "that device is not
798 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
799 "%s: nl_wait_for_ack failed adding %s interface: %s",
800 device, mondevice, get_nl_errmsg(-err));
812 * Try to remember the monitor device.
814 handlep->mondevice = strdup(mondevice);
815 if (handlep->mondevice == NULL) {
816 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
819 * Get rid of the monitor device.
821 del_mon_if(handle, sock_fd, state, device, mondevice);
827 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
828 "%s: nl_put failed adding %s interface",
835 del_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
836 const char *device, const char *mondevice)
842 ifindex = iface_get_id(sock_fd, mondevice, handle->errbuf);
848 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
849 "%s: failed to allocate netlink msg", device);
853 genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
854 0, NL80211_CMD_DEL_INTERFACE, 0);
855 NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
857 err = nl_send_auto_complete(state->nl_sock, msg);
859 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
860 "%s: nl_send_auto_complete failed deleting %s interface: %s",
861 device, mondevice, get_nl_errmsg(-err));
865 err = nl_wait_for_ack(state->nl_sock);
867 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
868 "%s: nl_wait_for_ack failed adding %s interface: %s",
869 device, mondevice, get_nl_errmsg(-err));
881 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
882 "%s: nl_put failed deleting %s interface",
889 enter_rfmon_mode_mac80211(pcap_t *handle, int sock_fd, const char *device)
891 struct pcap_linux *handlep = handle->priv;
893 char phydev_path[PATH_MAX+1];
894 struct nl80211_state nlstate;
899 * Is this a mac80211 device?
901 ret = get_mac80211_phydev(handle, device, phydev_path, PATH_MAX);
903 return ret; /* error */
905 return 0; /* no error, but not mac80211 device */
908 * XXX - is this already a monN device?
910 * Is that determined by old Wireless Extensions ioctls?
914 * OK, it's apparently a mac80211 device.
915 * Try to find an unused monN device for it.
917 ret = nl80211_init(handle, &nlstate, device);
920 for (n = 0; n < UINT_MAX; n++) {
924 char mondevice[3+10+1]; /* mon{UINT_MAX}\0 */
926 pcap_snprintf(mondevice, sizeof mondevice, "mon%u", n);
927 ret = add_mon_if(handle, sock_fd, &nlstate, device, mondevice);
930 * Success. We don't clean up the libnl state
931 * yet, as we'll be using it later.
937 * Hard failure. Just return ret; handle->errbuf
938 * has already been set.
940 nl80211_cleanup(&nlstate);
945 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
946 "%s: No free monN interfaces", device);
947 nl80211_cleanup(&nlstate);
954 * Sleep for .1 seconds.
957 delay.tv_nsec = 500000000;
958 nanosleep(&delay, NULL);
962 * If we haven't already done so, arrange to have
963 * "pcap_close_all()" called when we exit.
965 if (!pcap_do_addexit(handle)) {
967 * "atexit()" failed; don't put the interface
968 * in rfmon mode, just give up.
970 del_mon_if(handle, sock_fd, &nlstate, device,
972 nl80211_cleanup(&nlstate);
977 * Now configure the monitor interface up.
979 memset(&ifr, 0, sizeof(ifr));
980 strlcpy(ifr.ifr_name, handlep->mondevice, sizeof(ifr.ifr_name));
981 if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) {
982 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
983 errno, "%s: Can't get flags for %s", device,
985 del_mon_if(handle, sock_fd, &nlstate, device,
987 nl80211_cleanup(&nlstate);
990 ifr.ifr_flags |= IFF_UP|IFF_RUNNING;
991 if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
992 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
993 errno, "%s: Can't set flags for %s", device,
995 del_mon_if(handle, sock_fd, &nlstate, device,
997 nl80211_cleanup(&nlstate);
1002 * Success. Clean up the libnl state.
1004 nl80211_cleanup(&nlstate);
1007 * Note that we have to delete the monitor device when we close
1010 handlep->must_do_on_close |= MUST_DELETE_MONIF;
1013 * Add this to the list of pcaps to close when we exit.
1015 pcap_add_to_pcaps_to_close(handle);
1019 #endif /* HAVE_LIBNL */
1021 #ifdef IW_MODE_MONITOR
1023 * Bonding devices mishandle unknown ioctls; they fail with ENODEV
1024 * rather than ENOTSUP, EOPNOTSUPP, or ENOTTY, so Wireless Extensions
1025 * will fail with ENODEV if we try to do them on a bonding device,
1026 * making us return a "no such device" indication rather than just
1027 * saying "no Wireless Extensions".
1029 * So we check for bonding devices, if we can, before trying those
1030 * ioctls, by trying a bonding device information query ioctl to see
1031 * whether it succeeds.
1034 is_bonding_device(int fd, const char *device)
1036 #ifdef BOND_INFO_QUERY_IOCTL
1040 memset(&ifr, 0, sizeof ifr);
1041 strlcpy(ifr.ifr_name, device, sizeof ifr.ifr_name);
1042 memset(&ifb, 0, sizeof ifb);
1043 ifr.ifr_data = (caddr_t)&ifb;
1044 if (ioctl(fd, BOND_INFO_QUERY_IOCTL, &ifr) == 0)
1045 return 1; /* success, so it's a bonding device */
1046 #endif /* BOND_INFO_QUERY_IOCTL */
1048 return 0; /* no, it's not a bonding device */
1050 #endif /* IW_MODE_MONITOR */
1052 static int pcap_protocol(pcap_t *handle)
1056 protocol = handle->opt.protocol;
1058 protocol = ETH_P_ALL;
1060 return htons(protocol);
1064 pcap_can_set_rfmon_linux(pcap_t *handle)
1067 char phydev_path[PATH_MAX+1];
1070 #ifdef IW_MODE_MONITOR
1075 if (strcmp(handle->opt.device, "any") == 0) {
1077 * Monitor mode makes no sense on the "any" device.
1084 * Bleah. There doesn't seem to be a way to ask a mac80211
1085 * device, through libnl, whether it supports monitor mode;
1086 * we'll just check whether the device appears to be a
1087 * mac80211 device and, if so, assume the device supports
1090 * wmaster devices don't appear to support the Wireless
1091 * Extensions, but we can create a mon device for a
1092 * wmaster device, so we don't bother checking whether
1093 * a mac80211 device supports the Wireless Extensions.
1095 ret = get_mac80211_phydev(handle, handle->opt.device, phydev_path,
1098 return ret; /* error */
1100 return 1; /* mac80211 device */
1103 #ifdef IW_MODE_MONITOR
1105 * Bleah. There doesn't appear to be an ioctl to use to ask
1106 * whether a device supports monitor mode; we'll just do
1107 * SIOCGIWMODE and, if it succeeds, assume the device supports
1110 * Open a socket on which to attempt to get the mode.
1111 * (We assume that if we have Wireless Extensions support
1112 * we also have PF_PACKET support.)
1114 sock_fd = socket(PF_PACKET, SOCK_RAW, pcap_protocol(handle));
1115 if (sock_fd == -1) {
1116 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
1121 if (is_bonding_device(sock_fd, handle->opt.device)) {
1122 /* It's a bonding device, so don't even try. */
1128 * Attempt to get the current mode.
1130 strlcpy(ireq.ifr_ifrn.ifrn_name, handle->opt.device,
1131 sizeof ireq.ifr_ifrn.ifrn_name);
1132 if (ioctl(sock_fd, SIOCGIWMODE, &ireq) != -1) {
1134 * Well, we got the mode; assume we can set it.
1139 if (errno == ENODEV) {
1140 /* The device doesn't even exist. */
1141 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
1142 errno, "SIOCGIWMODE failed");
1144 return PCAP_ERROR_NO_SUCH_DEVICE;
1152 * Grabs the number of dropped packets by the interface from /proc/net/dev.
1154 * XXX - what about /sys/class/net/{interface name}/rx_*? There are
1155 * individual devices giving, in ASCII, various rx_ and tx_ statistics.
1157 * Or can we get them in binary form from netlink?
1160 linux_if_drops(const char * if_name)
1165 int field_to_convert = 3, if_name_sz = strlen(if_name);
1166 long int dropped_pkts = 0;
1168 file = fopen("/proc/net/dev", "r");
1172 while (!dropped_pkts && fgets( buffer, sizeof(buffer), file ))
1174 /* search for 'bytes' -- if its in there, then
1175 that means we need to grab the fourth field. otherwise
1176 grab the third field. */
1177 if (field_to_convert != 4 && strstr(buffer, "bytes"))
1179 field_to_convert = 4;
1183 /* find iface and make sure it actually matches -- space before the name and : after it */
1184 if ((bufptr = strstr(buffer, if_name)) &&
1185 (bufptr == buffer || *(bufptr-1) == ' ') &&
1186 *(bufptr + if_name_sz) == ':')
1188 bufptr = bufptr + if_name_sz + 1;
1190 /* grab the nth field from it */
1191 while( --field_to_convert && *bufptr != '\0')
1193 while (*bufptr != '\0' && *(bufptr++) == ' ');
1194 while (*bufptr != '\0' && *(bufptr++) != ' ');
1197 /* get rid of any final spaces */
1198 while (*bufptr != '\0' && *bufptr == ' ') bufptr++;
1200 if (*bufptr != '\0')
1201 dropped_pkts = strtol(bufptr, NULL, 10);
1208 return dropped_pkts;
1213 * With older kernels promiscuous mode is kind of interesting because we
1214 * have to reset the interface before exiting. The problem can't really
1215 * be solved without some daemon taking care of managing usage counts.
1216 * If we put the interface into promiscuous mode, we set a flag indicating
1217 * that we must take it out of that mode when the interface is closed,
1218 * and, when closing the interface, if that flag is set we take it out
1219 * of promiscuous mode.
1221 * Even with newer kernels, we have the same issue with rfmon mode.
1224 static void pcap_cleanup_linux( pcap_t *handle )
1226 struct pcap_linux *handlep = handle->priv;
1229 struct nl80211_state nlstate;
1231 #endif /* HAVE_LIBNL */
1232 #ifdef IW_MODE_MONITOR
1235 #endif /* IW_MODE_MONITOR */
1237 if (handlep->must_do_on_close != 0) {
1239 * There's something we have to do when closing this
1242 if (handlep->must_do_on_close & MUST_CLEAR_PROMISC) {
1244 * We put the interface into promiscuous mode;
1245 * take it out of promiscuous mode.
1247 * XXX - if somebody else wants it in promiscuous
1248 * mode, this code cannot know that, so it'll take
1249 * it out of promiscuous mode. That's not fixable
1250 * in 2.0[.x] kernels.
1252 memset(&ifr, 0, sizeof(ifr));
1253 strlcpy(ifr.ifr_name, handlep->device,
1254 sizeof(ifr.ifr_name));
1255 if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
1257 "Can't restore interface %s flags (SIOCGIFFLAGS failed: %s).\n"
1258 "Please adjust manually.\n"
1259 "Hint: This can't happen with Linux >= 2.2.0.\n",
1260 handlep->device, strerror(errno));
1262 if (ifr.ifr_flags & IFF_PROMISC) {
1264 * Promiscuous mode is currently on;
1267 ifr.ifr_flags &= ~IFF_PROMISC;
1268 if (ioctl(handle->fd, SIOCSIFFLAGS,
1271 "Can't restore interface %s flags (SIOCSIFFLAGS failed: %s).\n"
1272 "Please adjust manually.\n"
1273 "Hint: This can't happen with Linux >= 2.2.0.\n",
1282 if (handlep->must_do_on_close & MUST_DELETE_MONIF) {
1283 ret = nl80211_init(handle, &nlstate, handlep->device);
1285 ret = del_mon_if(handle, handle->fd, &nlstate,
1286 handlep->device, handlep->mondevice);
1287 nl80211_cleanup(&nlstate);
1291 "Can't delete monitor interface %s (%s).\n"
1292 "Please delete manually.\n",
1293 handlep->mondevice, handle->errbuf);
1296 #endif /* HAVE_LIBNL */
1298 #ifdef IW_MODE_MONITOR
1299 if (handlep->must_do_on_close & MUST_CLEAR_RFMON) {
1301 * We put the interface into rfmon mode;
1302 * take it out of rfmon mode.
1304 * XXX - if somebody else wants it in rfmon
1305 * mode, this code cannot know that, so it'll take
1306 * it out of rfmon mode.
1310 * First, take the interface down if it's up;
1311 * otherwise, we might get EBUSY.
1312 * If we get errors, just drive on and print
1313 * a warning if we can't restore the mode.
1316 memset(&ifr, 0, sizeof(ifr));
1317 strlcpy(ifr.ifr_name, handlep->device,
1318 sizeof(ifr.ifr_name));
1319 if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) != -1) {
1320 if (ifr.ifr_flags & IFF_UP) {
1321 oldflags = ifr.ifr_flags;
1322 ifr.ifr_flags &= ~IFF_UP;
1323 if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1)
1324 oldflags = 0; /* didn't set, don't restore */
1329 * Now restore the mode.
1331 strlcpy(ireq.ifr_ifrn.ifrn_name, handlep->device,
1332 sizeof ireq.ifr_ifrn.ifrn_name);
1333 ireq.u.mode = handlep->oldmode;
1334 if (ioctl(handle->fd, SIOCSIWMODE, &ireq) == -1) {
1336 * Scientist, you've failed.
1339 "Can't restore interface %s wireless mode (SIOCSIWMODE failed: %s).\n"
1340 "Please adjust manually.\n",
1341 handlep->device, strerror(errno));
1345 * Now bring the interface back up if we brought
1348 if (oldflags != 0) {
1349 ifr.ifr_flags = oldflags;
1350 if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
1352 "Can't bring interface %s back up (SIOCSIFFLAGS failed: %s).\n"
1353 "Please adjust manually.\n",
1354 handlep->device, strerror(errno));
1358 #endif /* IW_MODE_MONITOR */
1361 * Take this pcap out of the list of pcaps for which we
1362 * have to take the interface out of some mode.
1364 pcap_remove_from_pcaps_to_close(handle);
1367 if (handlep->mondevice != NULL) {
1368 free(handlep->mondevice);
1369 handlep->mondevice = NULL;
1371 if (handlep->device != NULL) {
1372 free(handlep->device);
1373 handlep->device = NULL;
1375 pcap_cleanup_live_common(handle);
1379 * Set the timeout to be used in poll() with memory-mapped packet capture.
1382 set_poll_timeout(struct pcap_linux *handlep)
1384 #ifdef HAVE_TPACKET3
1385 struct utsname utsname;
1386 char *version_component, *endp;
1388 int broken_tpacket_v3 = 1;
1391 * Some versions of TPACKET_V3 have annoying bugs/misfeatures
1392 * around which we have to work. Determine if we have those
1395 if (uname(&utsname) == 0) {
1397 * 3.19 is the first release with a fixed version of
1398 * TPACKET_V3. We treat anything before that as
1399 * not haveing a fixed version; that may really mean
1400 * it has *no* version.
1402 version_component = utsname.release;
1403 major = strtol(version_component, &endp, 10);
1404 if (endp != version_component && *endp == '.') {
1406 * OK, that was a valid major version.
1407 * Get the minor version.
1409 version_component = endp + 1;
1410 minor = strtol(version_component, &endp, 10);
1411 if (endp != version_component &&
1412 (*endp == '.' || *endp == '\0')) {
1414 * OK, that was a valid minor version.
1415 * Is this 3.19 or newer?
1417 if (major >= 4 || (major == 3 && minor >= 19)) {
1418 /* Yes. TPACKET_V3 works correctly. */
1419 broken_tpacket_v3 = 0;
1425 if (handlep->timeout == 0) {
1426 #ifdef HAVE_TPACKET3
1428 * XXX - due to a set of (mis)features in the TPACKET_V3
1429 * kernel code prior to the 3.19 kernel, blocking forever
1430 * with a TPACKET_V3 socket can, if few packets are
1431 * arriving and passing the socket filter, cause most
1432 * packets to be dropped. See libpcap issue #335 for the
1433 * full painful story.
1435 * The workaround is to have poll() time out very quickly,
1436 * so we grab the frames handed to us, and return them to
1439 if (handlep->tp_version == TPACKET_V3 && broken_tpacket_v3)
1440 handlep->poll_timeout = 1; /* don't block for very long */
1443 handlep->poll_timeout = -1; /* block forever */
1444 } else if (handlep->timeout > 0) {
1445 #ifdef HAVE_TPACKET3
1447 * For TPACKET_V3, the timeout is handled by the kernel,
1448 * so block forever; that way, we don't get extra timeouts.
1449 * Don't do that if we have a broken TPACKET_V3, though.
1451 if (handlep->tp_version == TPACKET_V3 && !broken_tpacket_v3)
1452 handlep->poll_timeout = -1; /* block forever, let TPACKET_V3 wake us up */
1455 handlep->poll_timeout = handlep->timeout; /* block for that amount of time */
1458 * Non-blocking mode; we call poll() to pick up error
1459 * indications, but we don't want it to wait for
1462 handlep->poll_timeout = 0;
1467 * Get a handle for a live capture from the given device. You can
1468 * pass NULL as device to get all packages (without link level
1469 * information of course). If you pass 1 as promisc the interface
1470 * will be set to promiscous mode (XXX: I think this usage should
1471 * be deprecated and functions be added to select that later allow
1472 * modification of that values -- Torsten).
1475 pcap_activate_linux(pcap_t *handle)
1477 struct pcap_linux *handlep = handle->priv;
1483 device = handle->opt.device;
1486 * Make sure the name we were handed will fit into the ioctls we
1487 * might perform on the device; if not, return a "No such device"
1488 * indication, as the Linux kernel shouldn't support creating
1489 * a device whose name won't fit into those ioctls.
1491 * "Will fit" means "will fit, complete with a null terminator",
1492 * so if the length, which does *not* include the null terminator,
1493 * is greater than *or equal to* the size of the field into which
1494 * we'll be copying it, that won't fit.
1496 if (strlen(device) >= sizeof(ifr.ifr_name)) {
1497 status = PCAP_ERROR_NO_SUCH_DEVICE;
1502 * Turn a negative snapshot value (invalid), a snapshot value of
1503 * 0 (unspecified), or a value bigger than the normal maximum
1504 * value, into the maximum allowed value.
1506 * If some application really *needs* a bigger snapshot
1507 * length, we should just increase MAXIMUM_SNAPLEN.
1509 if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
1510 handle->snapshot = MAXIMUM_SNAPLEN;
1512 handle->inject_op = pcap_inject_linux;
1513 handle->setfilter_op = pcap_setfilter_linux;
1514 handle->setdirection_op = pcap_setdirection_linux;
1515 handle->set_datalink_op = pcap_set_datalink_linux;
1516 handle->getnonblock_op = pcap_getnonblock_fd;
1517 handle->setnonblock_op = pcap_setnonblock_fd;
1518 handle->cleanup_op = pcap_cleanup_linux;
1519 handle->read_op = pcap_read_linux;
1520 handle->stats_op = pcap_stats_linux;
1523 * The "any" device is a special device which causes us not
1524 * to bind to a particular device and thus to look at all
1527 if (strcmp(device, "any") == 0) {
1528 if (handle->opt.promisc) {
1529 handle->opt.promisc = 0;
1530 /* Just a warning. */
1531 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
1532 "Promiscuous mode not supported on the \"any\" device");
1533 status = PCAP_WARNING_PROMISC_NOTSUP;
1537 handlep->device = strdup(device);
1538 if (handlep->device == NULL) {
1539 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
1544 /* copy timeout value */
1545 handlep->timeout = handle->opt.timeout;
1548 * If we're in promiscuous mode, then we probably want
1549 * to see when the interface drops packets too, so get an
1550 * initial count from /proc/net/dev
1552 if (handle->opt.promisc)
1553 handlep->proc_dropped = linux_if_drops(handlep->device);
1556 * Current Linux kernels use the protocol family PF_PACKET to
1557 * allow direct access to all packets on the network while
1558 * older kernels had a special socket type SOCK_PACKET to
1559 * implement this feature.
1560 * While this old implementation is kind of obsolete we need
1561 * to be compatible with older kernels for a while so we are
1562 * trying both methods with the newer method preferred.
1564 ret = activate_new(handle);
1567 * Fatal error with the new way; just fail.
1568 * ret has the error return; if it's PCAP_ERROR,
1569 * handle->errbuf has been set appropriately.
1577 * Try to use memory-mapped access.
1579 switch (activate_mmap(handle, &status)) {
1583 * We succeeded. status has been
1584 * set to the status to return,
1585 * which might be 0, or might be
1586 * a PCAP_WARNING_ value.
1588 * Set the timeout to use in poll() before
1591 set_poll_timeout(handlep);
1596 * Kernel doesn't support it - just continue
1597 * with non-memory-mapped access.
1603 * We failed to set up to use it, or the kernel
1604 * supports it, but we failed to enable it.
1605 * ret has been set to the error status to
1606 * return and, if it's PCAP_ERROR, handle->errbuf
1607 * contains the error message.
1613 else if (ret == 0) {
1614 /* Non-fatal error; try old way */
1615 if ((ret = activate_old(handle)) != 1) {
1617 * Both methods to open the packet socket failed.
1618 * Tidy up and report our failure (handle->errbuf
1619 * is expected to be set by the functions above).
1627 * We set up the socket, but not with memory-mapped access.
1629 if (handle->opt.buffer_size != 0) {
1631 * Set the socket buffer size to the specified value.
1633 if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF,
1634 &handle->opt.buffer_size,
1635 sizeof(handle->opt.buffer_size)) == -1) {
1636 pcap_fmt_errmsg_for_errno(handle->errbuf,
1637 PCAP_ERRBUF_SIZE, errno, "SO_RCVBUF");
1638 status = PCAP_ERROR;
1643 /* Allocate the buffer */
1645 handle->buffer = malloc(handle->bufsize + handle->offset);
1646 if (!handle->buffer) {
1647 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
1649 status = PCAP_ERROR;
1654 * "handle->fd" is a socket, so "select()" and "poll()"
1655 * should work on it.
1657 handle->selectable_fd = handle->fd;
1662 pcap_cleanup_linux(handle);
1667 * Read at most max_packets from the capture stream and call the callback
1668 * for each of them. Returns the number of packets handled or -1 if an
1672 pcap_read_linux(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
1675 * Currently, on Linux only one packet is delivered per read,
1678 return pcap_read_packet(handle, callback, user);
1682 pcap_set_datalink_linux(pcap_t *handle, int dlt)
1684 handle->linktype = dlt;
1689 * linux_check_direction()
1691 * Do checks based on packet direction.
1694 linux_check_direction(const pcap_t *handle, const struct sockaddr_ll *sll)
1696 struct pcap_linux *handlep = handle->priv;
1698 if (sll->sll_pkttype == PACKET_OUTGOING) {
1701 * If this is from the loopback device, reject it;
1702 * we'll see the packet as an incoming packet as well,
1703 * and we don't want to see it twice.
1705 if (sll->sll_ifindex == handlep->lo_ifindex)
1709 * If this is an outgoing CAN or CAN FD frame, and
1710 * the user doesn't only want outgoing packets,
1711 * reject it; CAN devices and drivers, and the CAN
1712 * stack, always arrange to loop back transmitted
1713 * packets, so they also appear as incoming packets.
1714 * We don't want duplicate packets, and we can't
1715 * easily distinguish packets looped back by the CAN
1716 * layer than those received by the CAN layer, so we
1717 * eliminate this packet instead.
1719 if ((sll->sll_protocol == LINUX_SLL_P_CAN ||
1720 sll->sll_protocol == LINUX_SLL_P_CANFD) &&
1721 handle->direction != PCAP_D_OUT)
1725 * If the user only wants incoming packets, reject it.
1727 if (handle->direction == PCAP_D_IN)
1732 * If the user only wants outgoing packets, reject it.
1734 if (handle->direction == PCAP_D_OUT)
1741 * Read a packet from the socket calling the handler provided by
1742 * the user. Returns the number of packets received or -1 if an
1746 pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata)
1748 struct pcap_linux *handlep = handle->priv;
1751 #ifdef HAVE_PF_PACKET_SOCKETS
1752 struct sockaddr_ll from;
1753 struct sll_header *hdrp;
1755 struct sockaddr from;
1757 #if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI)
1760 struct cmsghdr *cmsg;
1762 struct cmsghdr cmsg;
1763 char buf[CMSG_SPACE(sizeof(struct tpacket_auxdata))];
1765 #else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI) */
1767 #endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI) */
1768 int packet_len, caplen;
1769 struct pcap_pkthdr pcap_header;
1771 struct bpf_aux_data aux_data;
1772 #ifdef HAVE_PF_PACKET_SOCKETS
1774 * If this is a cooked device, leave extra room for a
1775 * fake packet header.
1777 if (handlep->cooked)
1778 offset = SLL_HDR_LEN;
1783 * This system doesn't have PF_PACKET sockets, so it doesn't
1784 * support cooked devices.
1790 * Receive a single packet from the kernel.
1791 * We ignore EINTR, as that might just be due to a signal
1792 * being delivered - if the signal should interrupt the
1793 * loop, the signal handler should call pcap_breakloop()
1794 * to set handle->break_loop (we ignore it on other
1795 * platforms as well).
1796 * We also ignore ENETDOWN, so that we can continue to
1797 * capture traffic if the interface goes down and comes
1798 * back up again; comments in the kernel indicate that
1799 * we'll just block waiting for packets if we try to
1800 * receive from a socket that delivered ENETDOWN, and,
1801 * if we're using a memory-mapped buffer, we won't even
1802 * get notified of "network down" events.
1804 bp = (u_char *)handle->buffer + handle->offset;
1806 #if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI)
1807 msg.msg_name = &from;
1808 msg.msg_namelen = sizeof(from);
1811 msg.msg_control = &cmsg_buf;
1812 msg.msg_controllen = sizeof(cmsg_buf);
1815 iov.iov_len = handle->bufsize - offset;
1816 iov.iov_base = bp + offset;
1817 #endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI) */
1821 * Has "pcap_breakloop()" been called?
1823 if (handle->break_loop) {
1825 * Yes - clear the flag that indicates that it has,
1826 * and return PCAP_ERROR_BREAK as an indication that
1827 * we were told to break out of the loop.
1829 handle->break_loop = 0;
1830 return PCAP_ERROR_BREAK;
1833 #if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI)
1834 packet_len = recvmsg(handle->fd, &msg, MSG_TRUNC);
1835 #else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI) */
1836 fromlen = sizeof(from);
1837 packet_len = recvfrom(
1838 handle->fd, bp + offset,
1839 handle->bufsize - offset, MSG_TRUNC,
1840 (struct sockaddr *) &from, &fromlen);
1841 #endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI) */
1842 } while (packet_len == -1 && errno == EINTR);
1844 /* Check if an error occured */
1846 if (packet_len == -1) {
1850 return 0; /* no packet there */
1854 * The device on which we're capturing went away.
1856 * XXX - we should really return
1857 * PCAP_ERROR_IFACE_NOT_UP, but pcap_dispatch()
1858 * etc. aren't defined to return that.
1860 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
1861 "The interface went down");
1865 pcap_fmt_errmsg_for_errno(handle->errbuf,
1866 PCAP_ERRBUF_SIZE, errno, "recvfrom");
1871 #ifdef HAVE_PF_PACKET_SOCKETS
1872 if (!handlep->sock_packet) {
1874 * Unfortunately, there is a window between socket() and
1875 * bind() where the kernel may queue packets from any
1876 * interface. If we're bound to a particular interface,
1877 * discard packets not from that interface.
1879 * (If socket filters are supported, we could do the
1880 * same thing we do when changing the filter; however,
1881 * that won't handle packet sockets without socket
1882 * filter support, and it's a bit more complicated.
1883 * It would save some instructions per packet, however.)
1885 if (handlep->ifindex != -1 &&
1886 from.sll_ifindex != handlep->ifindex)
1890 * Do checks based on packet direction.
1891 * We can only do this if we're using PF_PACKET; the
1892 * address returned for SOCK_PACKET is a "sockaddr_pkt"
1893 * which lacks the relevant packet type information.
1895 if (!linux_check_direction(handle, &from))
1900 #ifdef HAVE_PF_PACKET_SOCKETS
1902 * If this is a cooked device, fill in the fake packet header.
1904 if (handlep->cooked) {
1906 * Add the length of the fake header to the length
1907 * of packet data we read.
1909 packet_len += SLL_HDR_LEN;
1911 hdrp = (struct sll_header *)bp;
1912 hdrp->sll_pkttype = map_packet_type_to_sll_type(from.sll_pkttype);
1913 hdrp->sll_hatype = htons(from.sll_hatype);
1914 hdrp->sll_halen = htons(from.sll_halen);
1915 memcpy(hdrp->sll_addr, from.sll_addr,
1916 (from.sll_halen > SLL_ADDRLEN) ?
1919 hdrp->sll_protocol = from.sll_protocol;
1923 * Start out with no VLAN information.
1925 aux_data.vlan_tag_present = 0;
1926 aux_data.vlan_tag = 0;
1927 #if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI)
1928 if (handlep->vlan_offset != -1) {
1929 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
1930 struct tpacket_auxdata *aux;
1932 struct vlan_tag *tag;
1934 if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct tpacket_auxdata)) ||
1935 cmsg->cmsg_level != SOL_PACKET ||
1936 cmsg->cmsg_type != PACKET_AUXDATA) {
1938 * This isn't a PACKET_AUXDATA auxiliary
1944 aux = (struct tpacket_auxdata *)CMSG_DATA(cmsg);
1945 if (!VLAN_VALID(aux, aux)) {
1947 * There is no VLAN information in the
1953 len = (u_int)packet_len > iov.iov_len ? iov.iov_len : (u_int)packet_len;
1954 if (len < (u_int)handlep->vlan_offset)
1958 * Move everything in the header, except the
1959 * type field, down VLAN_TAG_LEN bytes, to
1960 * allow us to insert the VLAN tag between
1961 * that stuff and the type field.
1964 memmove(bp, bp + VLAN_TAG_LEN, handlep->vlan_offset);
1967 * Now insert the tag.
1969 tag = (struct vlan_tag *)(bp + handlep->vlan_offset);
1970 tag->vlan_tpid = htons(VLAN_TPID(aux, aux));
1971 tag->vlan_tci = htons(aux->tp_vlan_tci);
1974 * Save a flag indicating that we have a VLAN tag,
1975 * and the VLAN TCI, to bpf_aux_data struct for
1976 * use by the BPF filter if we're doing the
1977 * filtering in userland.
1979 aux_data.vlan_tag_present = 1;
1980 aux_data.vlan_tag = htons(aux->tp_vlan_tci) & 0x0fff;
1983 * Add the tag to the packet lengths.
1985 packet_len += VLAN_TAG_LEN;
1988 #endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI) */
1989 #endif /* HAVE_PF_PACKET_SOCKETS */
1992 * XXX: According to the kernel source we should get the real
1993 * packet len if calling recvfrom with MSG_TRUNC set. It does
1994 * not seem to work here :(, but it is supported by this code
1996 * To be honest the code RELIES on that feature so this is really
1997 * broken with 2.2.x kernels.
1998 * I spend a day to figure out what's going on and I found out
1999 * that the following is happening:
2001 * The packet comes from a random interface and the packet_rcv
2002 * hook is called with a clone of the packet. That code inserts
2003 * the packet into the receive queue of the packet socket.
2004 * If a filter is attached to that socket that filter is run
2005 * first - and there lies the problem. The default filter always
2006 * cuts the packet at the snaplen:
2011 * So the packet filter cuts down the packet. The recvfrom call
2012 * says "hey, it's only 68 bytes, it fits into the buffer" with
2013 * the result that we don't get the real packet length. This
2014 * is valid at least until kernel 2.2.17pre6.
2016 * We currently handle this by making a copy of the filter
2017 * program, fixing all "ret" instructions with non-zero
2018 * operands to have an operand of MAXIMUM_SNAPLEN so that the
2019 * filter doesn't truncate the packet, and supplying that modified
2020 * filter to the kernel.
2023 caplen = packet_len;
2024 if (caplen > handle->snapshot)
2025 caplen = handle->snapshot;
2027 /* Run the packet filter if not using kernel filter */
2028 if (handlep->filter_in_userland && handle->fcode.bf_insns) {
2029 if (bpf_filter_with_aux_data(handle->fcode.bf_insns, bp,
2030 packet_len, caplen, &aux_data) == 0) {
2031 /* rejected by filter */
2036 /* Fill in our own header data */
2038 /* get timestamp for this packet */
2039 #if defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS)
2040 if (handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO) {
2041 if (ioctl(handle->fd, SIOCGSTAMPNS, &pcap_header.ts) == -1) {
2042 pcap_fmt_errmsg_for_errno(handle->errbuf,
2043 PCAP_ERRBUF_SIZE, errno, "SIOCGSTAMPNS");
2049 if (ioctl(handle->fd, SIOCGSTAMP, &pcap_header.ts) == -1) {
2050 pcap_fmt_errmsg_for_errno(handle->errbuf,
2051 PCAP_ERRBUF_SIZE, errno, "SIOCGSTAMP");
2056 pcap_header.caplen = caplen;
2057 pcap_header.len = packet_len;
2062 * Arguably, we should count them before we check the filter,
2063 * as on many other platforms "ps_recv" counts packets
2064 * handed to the filter rather than packets that passed
2065 * the filter, but if filtering is done in the kernel, we
2066 * can't get a count of packets that passed the filter,
2067 * and that would mean the meaning of "ps_recv" wouldn't
2068 * be the same on all Linux systems.
2070 * XXX - it's not the same on all systems in any case;
2071 * ideally, we should have a "get the statistics" call
2072 * that supplies more counts and indicates which of them
2073 * it supplies, so that we supply a count of packets
2074 * handed to the filter only on platforms where that
2075 * information is available.
2077 * We count them here even if we can get the packet count
2078 * from the kernel, as we can only determine at run time
2079 * whether we'll be able to get it from the kernel (if
2080 * HAVE_STRUCT_TPACKET_STATS isn't defined, we can't get it from
2081 * the kernel, but if it is defined, the library might
2082 * have been built with a 2.4 or later kernel, but we
2083 * might be running on a 2.2[.x] kernel without Alexey
2084 * Kuznetzov's turbopacket patches, and thus the kernel
2085 * might not be able to supply those statistics). We
2086 * could, I guess, try, when opening the socket, to get
2087 * the statistics, and if we can not increment the count
2088 * here, but it's not clear that always incrementing
2089 * the count is more expensive than always testing a flag
2092 * We keep the count in "handlep->packets_read", and use that
2093 * for "ps_recv" if we can't get the statistics from the kernel.
2094 * We do that because, if we *can* get the statistics from
2095 * the kernel, we use "handlep->stat.ps_recv" and
2096 * "handlep->stat.ps_drop" as running counts, as reading the
2097 * statistics from the kernel resets the kernel statistics,
2098 * and if we directly increment "handlep->stat.ps_recv" here,
2099 * that means it will count packets *twice* on systems where
2100 * we can get kernel statistics - once here, and once in
2101 * pcap_stats_linux().
2103 handlep->packets_read++;
2105 /* Call the user supplied callback function */
2106 callback(userdata, &pcap_header, bp);
2112 pcap_inject_linux(pcap_t *handle, const void *buf, size_t size)
2114 struct pcap_linux *handlep = handle->priv;
2117 #ifdef HAVE_PF_PACKET_SOCKETS
2118 if (!handlep->sock_packet) {
2119 /* PF_PACKET socket */
2120 if (handlep->ifindex == -1) {
2122 * We don't support sending on the "any" device.
2124 strlcpy(handle->errbuf,
2125 "Sending packets isn't supported on the \"any\" device",
2130 if (handlep->cooked) {
2132 * We don't support sending on the "any" device.
2134 * XXX - how do you send on a bound cooked-mode
2136 * Is a "sendto()" required there?
2138 strlcpy(handle->errbuf,
2139 "Sending packets isn't supported in cooked mode",
2146 ret = send(handle->fd, buf, size, 0);
2148 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
2156 * Get the statistics for the given packet capture handle.
2157 * Reports the number of dropped packets iff the kernel supports
2158 * the PACKET_STATISTICS "getsockopt()" argument (2.4 and later
2159 * kernels, and 2.2[.x] kernels with Alexey Kuznetzov's turbopacket
2160 * patches); otherwise, that information isn't available, and we lie
2161 * and report 0 as the count of dropped packets.
2164 pcap_stats_linux(pcap_t *handle, struct pcap_stat *stats)
2166 struct pcap_linux *handlep = handle->priv;
2167 #ifdef HAVE_STRUCT_TPACKET_STATS
2168 #ifdef HAVE_TPACKET3
2170 * For sockets using TPACKET_V1 or TPACKET_V2, the extra
2171 * stuff at the end of a struct tpacket_stats_v3 will not
2172 * be filled in, and we don't look at it so this is OK even
2173 * for those sockets. In addition, the PF_PACKET socket
2174 * code in the kernel only uses the length parameter to
2175 * compute how much data to copy out and to indicate how
2176 * much data was copied out, so it's OK to base it on the
2177 * size of a struct tpacket_stats.
2179 * XXX - it's probably OK, in fact, to just use a
2180 * struct tpacket_stats for V3 sockets, as we don't
2181 * care about the tp_freeze_q_cnt stat.
2183 struct tpacket_stats_v3 kstats;
2184 #else /* HAVE_TPACKET3 */
2185 struct tpacket_stats kstats;
2186 #endif /* HAVE_TPACKET3 */
2187 socklen_t len = sizeof (struct tpacket_stats);
2188 #endif /* HAVE_STRUCT_TPACKET_STATS */
2190 long if_dropped = 0;
2193 * To fill in ps_ifdrop, we parse /proc/net/dev for the number
2195 if (handle->opt.promisc)
2197 if_dropped = handlep->proc_dropped;
2198 handlep->proc_dropped = linux_if_drops(handlep->device);
2199 handlep->stat.ps_ifdrop += (handlep->proc_dropped - if_dropped);
2202 #ifdef HAVE_STRUCT_TPACKET_STATS
2204 * Try to get the packet counts from the kernel.
2206 if (getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS,
2207 &kstats, &len) > -1) {
2209 * On systems where the PACKET_STATISTICS "getsockopt()"
2210 * argument is supported on PF_PACKET sockets:
2212 * "ps_recv" counts only packets that *passed* the
2213 * filter, not packets that didn't pass the filter.
2214 * This includes packets later dropped because we
2215 * ran out of buffer space.
2217 * "ps_drop" counts packets dropped because we ran
2218 * out of buffer space. It doesn't count packets
2219 * dropped by the interface driver. It counts only
2220 * packets that passed the filter.
2222 * See above for ps_ifdrop.
2224 * Both statistics include packets not yet read from
2225 * the kernel by libpcap, and thus not yet seen by
2228 * In "linux/net/packet/af_packet.c", at least in the
2229 * 2.4.9 kernel, "tp_packets" is incremented for every
2230 * packet that passes the packet filter *and* is
2231 * successfully queued on the socket; "tp_drops" is
2232 * incremented for every packet dropped because there's
2233 * not enough free space in the socket buffer.
2235 * When the statistics are returned for a PACKET_STATISTICS
2236 * "getsockopt()" call, "tp_drops" is added to "tp_packets",
2237 * so that "tp_packets" counts all packets handed to
2238 * the PF_PACKET socket, including packets dropped because
2239 * there wasn't room on the socket buffer - but not
2240 * including packets that didn't pass the filter.
2242 * In the BSD BPF, the count of received packets is
2243 * incremented for every packet handed to BPF, regardless
2244 * of whether it passed the filter.
2246 * We can't make "pcap_stats()" work the same on both
2247 * platforms, but the best approximation is to return
2248 * "tp_packets" as the count of packets and "tp_drops"
2249 * as the count of drops.
2251 * Keep a running total because each call to
2252 * getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS, ....
2253 * resets the counters to zero.
2255 handlep->stat.ps_recv += kstats.tp_packets;
2256 handlep->stat.ps_drop += kstats.tp_drops;
2257 *stats = handlep->stat;
2263 * If the error was EOPNOTSUPP, fall through, so that
2264 * if you build the library on a system with
2265 * "struct tpacket_stats" and run it on a system
2266 * that doesn't, it works as it does if the library
2267 * is built on a system without "struct tpacket_stats".
2269 if (errno != EOPNOTSUPP) {
2270 pcap_fmt_errmsg_for_errno(handle->errbuf,
2271 PCAP_ERRBUF_SIZE, errno, "pcap_stats");
2277 * On systems where the PACKET_STATISTICS "getsockopt()" argument
2278 * is not supported on PF_PACKET sockets:
2280 * "ps_recv" counts only packets that *passed* the filter,
2281 * not packets that didn't pass the filter. It does not
2282 * count packets dropped because we ran out of buffer
2285 * "ps_drop" is not supported.
2287 * "ps_ifdrop" is supported. It will return the number
2288 * of drops the interface reports in /proc/net/dev,
2289 * if that is available.
2291 * "ps_recv" doesn't include packets not yet read from
2292 * the kernel by libpcap.
2294 * We maintain the count of packets processed by libpcap in
2295 * "handlep->packets_read", for reasons described in the comment
2296 * at the end of pcap_read_packet(). We have no idea how many
2297 * packets were dropped by the kernel buffers -- but we know
2298 * how many the interface dropped, so we can return that.
2301 stats->ps_recv = handlep->packets_read;
2303 stats->ps_ifdrop = handlep->stat.ps_ifdrop;
2308 add_linux_if(pcap_if_list_t *devlistp, const char *ifname, int fd, char *errbuf)
2311 char name[512]; /* XXX - pick a size */
2313 struct ifreq ifrflags;
2316 * Get the interface name.
2320 while (*p != '\0' && isascii(*p) && !isspace(*p)) {
2323 * This could be the separator between a
2324 * name and an alias number, or it could be
2325 * the separator between a name with no
2326 * alias number and the next field.
2328 * If there's a colon after digits, it
2329 * separates the name and the alias number,
2330 * otherwise it separates the name and the
2334 while (isascii(*p) && isdigit(*p))
2338 * That was the next field,
2339 * not the alias number.
2350 * Get the flags for this interface.
2352 strlcpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
2353 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
2354 if (errno == ENXIO || errno == ENODEV)
2355 return (0); /* device doesn't actually exist - ignore it */
2356 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
2357 errno, "SIOCGIFFLAGS: %.*s",
2358 (int)sizeof(ifrflags.ifr_name),
2364 * Add an entry for this interface, with no addresses, if it's
2365 * not already in the list.
2367 if (find_or_add_if(devlistp, name, ifrflags.ifr_flags,
2368 get_if_flags, errbuf) == NULL) {
2379 * Get from "/sys/class/net" all interfaces listed there; if they're
2380 * already in the list of interfaces we have, that won't add another
2381 * instance, but if they're not, that'll add them.
2383 * We don't bother getting any addresses for them; it appears you can't
2384 * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
2385 * although some other types of addresses can be fetched with SIOCGIFADDR,
2386 * we don't bother with them for now.
2388 * We also don't fail if we couldn't open "/sys/class/net"; we just leave
2389 * the list of interfaces as is, and return 0, so that we can try
2390 * scanning /proc/net/dev.
2392 * Otherwise, we return 1 if we don't get an error and -1 if we do.
2395 scan_sys_class_net(pcap_if_list_t *devlistp, char *errbuf)
2397 DIR *sys_class_net_d;
2400 char subsystem_path[PATH_MAX+1];
2404 sys_class_net_d = opendir("/sys/class/net");
2405 if (sys_class_net_d == NULL) {
2407 * Don't fail if it doesn't exist at all.
2409 if (errno == ENOENT)
2413 * Fail if we got some other error.
2415 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
2416 errno, "Can't open /sys/class/net");
2421 * Create a socket from which to fetch interface information.
2423 fd = socket(PF_UNIX, SOCK_RAW, 0);
2425 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
2427 (void)closedir(sys_class_net_d);
2433 ent = readdir(sys_class_net_d);
2436 * Error or EOF; if errno != 0, it's an error.
2442 * Ignore "." and "..".
2444 if (strcmp(ent->d_name, ".") == 0 ||
2445 strcmp(ent->d_name, "..") == 0)
2449 * Ignore plain files; they do not have subdirectories
2450 * and thus have no attributes.
2452 if (ent->d_type == DT_REG)
2456 * Is there an "ifindex" file under that name?
2457 * (We don't care whether it's a directory or
2458 * a symlink; older kernels have directories
2459 * for devices, newer kernels have symlinks to
2462 pcap_snprintf(subsystem_path, sizeof subsystem_path,
2463 "/sys/class/net/%s/ifindex", ent->d_name);
2464 if (lstat(subsystem_path, &statb) != 0) {
2466 * Stat failed. Either there was an error
2467 * other than ENOENT, and we don't know if
2468 * this is an interface, or it's ENOENT,
2469 * and either some part of "/sys/class/net/{if}"
2470 * disappeared, in which case it probably means
2471 * the interface disappeared, or there's no
2472 * "ifindex" file, which means it's not a
2473 * network interface.
2479 * Attempt to add the interface.
2481 if (add_linux_if(devlistp, &ent->d_name[0], fd, errbuf) == -1) {
2489 * Well, we didn't fail for any other reason; did we
2490 * fail due to an error reading the directory?
2493 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
2494 errno, "Error reading /sys/class/net");
2500 (void)closedir(sys_class_net_d);
2505 * Get from "/proc/net/dev" all interfaces listed there; if they're
2506 * already in the list of interfaces we have, that won't add another
2507 * instance, but if they're not, that'll add them.
2509 * See comments from scan_sys_class_net().
2512 scan_proc_net_dev(pcap_if_list_t *devlistp, char *errbuf)
2521 proc_net_f = fopen("/proc/net/dev", "r");
2522 if (proc_net_f == NULL) {
2524 * Don't fail if it doesn't exist at all.
2526 if (errno == ENOENT)
2530 * Fail if we got some other error.
2532 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
2533 errno, "Can't open /proc/net/dev");
2538 * Create a socket from which to fetch interface information.
2540 fd = socket(PF_UNIX, SOCK_RAW, 0);
2542 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
2544 (void)fclose(proc_net_f);
2549 fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
2551 * Skip the first two lines - they're headers.
2559 * Skip leading white space.
2561 while (*p != '\0' && isascii(*p) && isspace(*p))
2563 if (*p == '\0' || *p == '\n')
2564 continue; /* blank line */
2567 * Attempt to add the interface.
2569 if (add_linux_if(devlistp, p, fd, errbuf) == -1) {
2577 * Well, we didn't fail for any other reason; did we
2578 * fail due to an error reading the file?
2580 if (ferror(proc_net_f)) {
2581 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
2582 errno, "Error reading /proc/net/dev");
2588 (void)fclose(proc_net_f);
2593 * Description string for the "any" device.
2595 static const char any_descr[] = "Pseudo-device that captures on all interfaces";
2598 * A SOCK_PACKET or PF_PACKET socket can be bound to any network interface.
2601 can_be_bound(const char *name _U_)
2607 * Get additional flags for a device, using SIOCGIFMEDIA.
2610 get_if_flags(const char *name, bpf_u_int32 *flags, char *errbuf)
2614 unsigned int arptype;
2616 struct ethtool_value info;
2618 if (*flags & PCAP_IF_LOOPBACK) {
2620 * Loopback devices aren't wireless, and "connected"/
2621 * "disconnected" doesn't apply to them.
2623 *flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
2627 sock = socket(AF_INET, SOCK_DGRAM, 0);
2629 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, errno,
2630 "Can't create socket to get ethtool information for %s",
2636 * OK, what type of network is this?
2637 * In particular, is it wired or wireless?
2639 if (is_wifi(sock, name)) {
2641 * Wi-Fi, hence wireless.
2643 *flags |= PCAP_IF_WIRELESS;
2646 * OK, what does /sys/class/net/{if}/type contain?
2647 * (We don't use that for Wi-Fi, as it'll report
2648 * "Ethernet", i.e. ARPHRD_ETHER, for non-monitor-
2653 if (asprintf(&pathstr, "/sys/class/net/%s/type", name) == -1) {
2654 pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
2655 "%s: Can't generate path name string for /sys/class/net device",
2660 fh = fopen(pathstr, "r");
2662 if (fscanf(fh, "%u", &arptype) == 1) {
2664 * OK, we got an ARPHRD_ type; what is it?
2668 #ifdef ARPHRD_LOOPBACK
2669 case ARPHRD_LOOPBACK:
2671 * These are types to which
2672 * "connected" and "disconnected"
2673 * don't apply, so don't bother
2676 * XXX - add other types?
2685 case ARPHRD_IEEE80211:
2686 case ARPHRD_IEEE80211_PRISM:
2687 case ARPHRD_IEEE80211_RADIOTAP:
2688 #ifdef ARPHRD_IEEE802154
2689 case ARPHRD_IEEE802154:
2691 #ifdef ARPHRD_IEEE802154_MONITOR
2692 case ARPHRD_IEEE802154_MONITOR:
2694 #ifdef ARPHRD_6LOWPAN
2695 case ARPHRD_6LOWPAN:
2698 * Various wireless types.
2700 *flags |= PCAP_IF_WIRELESS;
2709 #ifdef ETHTOOL_GLINK
2710 memset(&ifr, 0, sizeof(ifr));
2711 strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
2712 info.cmd = ETHTOOL_GLINK;
2713 ifr.ifr_data = (caddr_t)&info;
2714 if (ioctl(sock, SIOCETHTOOL, &ifr) == -1) {
2715 int save_errno = errno;
2717 switch (save_errno) {
2722 * OK, this OS version or driver doesn't support
2723 * asking for this information.
2724 * XXX - distinguish between "this doesn't
2725 * support ethtool at all because it's not
2726 * that type of device" vs. "this doesn't
2727 * support ethtool even though it's that
2728 * type of device", and return "unknown".
2730 *flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
2736 * OK, no such device.
2737 * The user will find that out when they try to
2738 * activate the device; just say "OK" and
2739 * don't set anything.
2748 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
2750 "%s: SIOCETHTOOL(ETHTOOL_GLINK) ioctl failed",
2764 *flags |= PCAP_IF_CONNECTION_STATUS_CONNECTED;
2767 * It's disconnected.
2769 *flags |= PCAP_IF_CONNECTION_STATUS_DISCONNECTED;
2778 pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
2783 * Get the list of regular interfaces first.
2785 if (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
2786 get_if_flags) == -1)
2787 return (-1); /* failure */
2790 * Read "/sys/class/net", and add to the list of interfaces all
2791 * interfaces listed there that we don't already have, because,
2792 * on Linux, SIOCGIFCONF reports only interfaces with IPv4 addresses,
2793 * and even getifaddrs() won't return information about
2794 * interfaces with no addresses, so you need to read "/sys/class/net"
2795 * to get the names of the rest of the interfaces.
2797 ret = scan_sys_class_net(devlistp, errbuf);
2799 return (-1); /* failed */
2802 * No /sys/class/net; try reading /proc/net/dev instead.
2804 if (scan_proc_net_dev(devlistp, errbuf) == -1)
2809 * Add the "any" device.
2810 * As it refers to all network devices, not to any particular
2811 * network device, the notion of "connected" vs. "disconnected"
2814 if (add_dev(devlistp, "any",
2815 PCAP_IF_UP|PCAP_IF_RUNNING|PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
2816 any_descr, errbuf) == NULL)
2823 * Attach the given BPF code to the packet capture device.
2826 pcap_setfilter_linux_common(pcap_t *handle, struct bpf_program *filter,
2829 struct pcap_linux *handlep;
2830 #ifdef SO_ATTACH_FILTER
2831 struct sock_fprog fcode;
2832 int can_filter_in_kernel;
2839 strlcpy(handle->errbuf, "setfilter: No filter specified",
2844 handlep = handle->priv;
2846 /* Make our private copy of the filter */
2848 if (install_bpf_program(handle, filter) < 0)
2849 /* install_bpf_program() filled in errbuf */
2853 * Run user level packet filter by default. Will be overriden if
2854 * installing a kernel filter succeeds.
2856 handlep->filter_in_userland = 1;
2858 /* Install kernel level filter if possible */
2860 #ifdef SO_ATTACH_FILTER
2862 if (handle->fcode.bf_len > USHRT_MAX) {
2864 * fcode.len is an unsigned short for current kernel.
2865 * I have yet to see BPF-Code with that much
2866 * instructions but still it is possible. So for the
2867 * sake of correctness I added this check.
2869 fprintf(stderr, "Warning: Filter too complex for kernel\n");
2871 fcode.filter = NULL;
2872 can_filter_in_kernel = 0;
2874 #endif /* USHRT_MAX */
2877 * Oh joy, the Linux kernel uses struct sock_fprog instead
2878 * of struct bpf_program and of course the length field is
2879 * of different size. Pointed out by Sebastian
2881 * Oh, and we also need to fix it up so that all "ret"
2882 * instructions with non-zero operands have MAXIMUM_SNAPLEN
2883 * as the operand if we're not capturing in memory-mapped
2884 * mode, and so that, if we're in cooked mode, all memory-
2885 * reference instructions use special magic offsets in
2886 * references to the link-layer header and assume that the
2887 * link-layer payload begins at 0; "fix_program()" will do
2890 switch (fix_program(handle, &fcode, is_mmapped)) {
2895 * Fatal error; just quit.
2896 * (The "default" case shouldn't happen; we
2897 * return -1 for that reason.)
2903 * The program performed checks that we can't make
2904 * work in the kernel.
2906 can_filter_in_kernel = 0;
2911 * We have a filter that'll work in the kernel.
2913 can_filter_in_kernel = 1;
2919 * NOTE: at this point, we've set both the "len" and "filter"
2920 * fields of "fcode". As of the 2.6.32.4 kernel, at least,
2921 * those are the only members of the "sock_fprog" structure,
2922 * so we initialize every member of that structure.
2924 * If there is anything in "fcode" that is not initialized,
2925 * it is either a field added in a later kernel, or it's
2928 * If a new field is added, this code needs to be updated
2929 * to set it correctly.
2931 * If there are no other fields, then:
2933 * if the Linux kernel looks at the padding, it's
2936 * if the Linux kernel doesn't look at the padding,
2937 * then if some tool complains that we're passing
2938 * uninitialized data to the kernel, then the tool
2939 * is buggy and needs to understand that it's just
2942 if (can_filter_in_kernel) {
2943 if ((err = set_kernel_filter(handle, &fcode)) == 0)
2946 * Installation succeded - using kernel filter,
2947 * so userland filtering not needed.
2949 handlep->filter_in_userland = 0;
2951 else if (err == -1) /* Non-fatal error */
2954 * Print a warning if we weren't able to install
2955 * the filter for a reason other than "this kernel
2956 * isn't configured to support socket filters.
2958 if (errno != ENOPROTOOPT && errno != EOPNOTSUPP) {
2960 "Warning: Kernel filter failed: %s\n",
2961 pcap_strerror(errno));
2967 * If we're not using the kernel filter, get rid of any kernel
2968 * filter that might've been there before, e.g. because the
2969 * previous filter could work in the kernel, or because some other
2970 * code attached a filter to the socket by some means other than
2971 * calling "pcap_setfilter()". Otherwise, the kernel filter may
2972 * filter out packets that would pass the new userland filter.
2974 if (handlep->filter_in_userland) {
2975 if (reset_kernel_filter(handle) == -1) {
2976 pcap_fmt_errmsg_for_errno(handle->errbuf,
2977 PCAP_ERRBUF_SIZE, errno,
2978 "can't remove kernel filter");
2979 err = -2; /* fatal error */
2984 * Free up the copy of the filter that was made by "fix_program()".
2986 if (fcode.filter != NULL)
2992 #endif /* SO_ATTACH_FILTER */
2998 pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter)
3000 return pcap_setfilter_linux_common(handle, filter, 0);
3005 * Set direction flag: Which packets do we accept on a forwarding
3006 * single device? IN, OUT or both?
3009 pcap_setdirection_linux(pcap_t *handle, pcap_direction_t d)
3011 #ifdef HAVE_PF_PACKET_SOCKETS
3012 struct pcap_linux *handlep = handle->priv;
3014 if (!handlep->sock_packet) {
3015 handle->direction = d;
3020 * We're not using PF_PACKET sockets, so we can't determine
3021 * the direction of the packet.
3023 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
3024 "Setting direction is not supported on SOCK_PACKET sockets");
3028 #ifdef HAVE_PF_PACKET_SOCKETS
3030 * Map the PACKET_ value to a LINUX_SLL_ value; we
3031 * want the same numerical value to be used in
3032 * the link-layer header even if the numerical values
3033 * for the PACKET_ #defines change, so that programs
3034 * that look at the packet type field will always be
3035 * able to handle DLT_LINUX_SLL captures.
3038 map_packet_type_to_sll_type(short int sll_pkttype)
3040 switch (sll_pkttype) {
3043 return htons(LINUX_SLL_HOST);
3045 case PACKET_BROADCAST:
3046 return htons(LINUX_SLL_BROADCAST);
3048 case PACKET_MULTICAST:
3049 return htons(LINUX_SLL_MULTICAST);
3051 case PACKET_OTHERHOST:
3052 return htons(LINUX_SLL_OTHERHOST);
3054 case PACKET_OUTGOING:
3055 return htons(LINUX_SLL_OUTGOING);
3065 #ifndef IW_MODE_MONITOR
3068 , const char *device)
3072 #ifdef IW_MODE_MONITOR
3073 char errbuf[PCAP_ERRBUF_SIZE];
3077 * See if there's a sysfs wireless directory for it.
3078 * If so, it's a wireless interface.
3080 if (asprintf(&pathstr, "/sys/class/net/%s/wireless", device) == -1) {
3082 * Just give up here.
3086 if (stat(pathstr, &statb) == 0) {
3092 #ifdef IW_MODE_MONITOR
3094 * OK, maybe it's not wireless, or maybe this kernel doesn't
3095 * support sysfs. Try the wireless extensions.
3097 if (has_wext(sock_fd, device, errbuf) == 1) {
3099 * It supports the wireless extensions, so it's a Wi-Fi
3109 * Linux uses the ARP hardware type to identify the type of an
3110 * interface. pcap uses the DLT_xxx constants for this. This
3111 * function takes a pointer to a "pcap_t", and an ARPHRD_xxx
3112 * constant, as arguments, and sets "handle->linktype" to the
3113 * appropriate DLT_XXX constant and sets "handle->offset" to
3114 * the appropriate value (to make "handle->offset" plus link-layer
3115 * header length be a multiple of 4, so that the link-layer payload
3116 * will be aligned on a 4-byte boundary when capturing packets).
3117 * (If the offset isn't set here, it'll be 0; add code as appropriate
3118 * for cases where it shouldn't be 0.)
3120 * If "cooked_ok" is non-zero, we can use DLT_LINUX_SLL and capture
3121 * in cooked mode; otherwise, we can't use cooked mode, so we have
3122 * to pick some type that works in raw mode, or fail.
3124 * Sets the link type to -1 if unable to map the type.
3126 static void map_arphrd_to_dlt(pcap_t *handle, int sock_fd, int arptype,
3127 const char *device, int cooked_ok)
3129 static const char cdma_rmnet[] = "cdma_rmnet";
3135 * For various annoying reasons having to do with DHCP
3136 * software, some versions of Android give the mobile-
3137 * phone-network interface an ARPHRD_ value of
3138 * ARPHRD_ETHER, even though the packets supplied by
3139 * that interface have no link-layer header, and begin
3140 * with an IP header, so that the ARPHRD_ value should
3143 * Detect those devices by checking the device name, and
3144 * use DLT_RAW for them.
3146 if (strncmp(device, cdma_rmnet, sizeof cdma_rmnet - 1) == 0) {
3147 handle->linktype = DLT_RAW;
3152 * Is this a real Ethernet device? If so, give it a
3153 * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
3154 * that an application can let you choose it, in case you're
3155 * capturing DOCSIS traffic that a Cisco Cable Modem
3156 * Termination System is putting out onto an Ethernet (it
3157 * doesn't put an Ethernet header onto the wire, it puts raw
3158 * DOCSIS frames out on the wire inside the low-level
3159 * Ethernet framing).
3161 * XXX - are there any other sorts of "fake Ethernet" that
3162 * have ARPHRD_ETHER but that shouldn't offer DLT_DOCSIS as
3163 * a Cisco CMTS won't put traffic onto it or get traffic
3164 * bridged onto it? ISDN is handled in "activate_new()",
3165 * as we fall back on cooked mode there, and we use
3166 * is_wifi() to check for 802.11 devices; are there any
3169 if (!is_wifi(sock_fd, device)) {
3171 * It's not a Wi-Fi device; offer DOCSIS.
3173 handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
3175 * If that fails, just leave the list empty.
3177 if (handle->dlt_list != NULL) {
3178 handle->dlt_list[0] = DLT_EN10MB;
3179 handle->dlt_list[1] = DLT_DOCSIS;
3180 handle->dlt_count = 2;
3185 case ARPHRD_METRICOM:
3186 case ARPHRD_LOOPBACK:
3187 handle->linktype = DLT_EN10MB;
3192 handle->linktype = DLT_EN3MB;
3196 handle->linktype = DLT_AX25_KISS;
3200 handle->linktype = DLT_PRONET;
3204 handle->linktype = DLT_CHAOS;
3207 #define ARPHRD_CAN 280
3211 * Map this to DLT_LINUX_SLL; that way, CAN frames will
3212 * have ETH_P_CAN/LINUX_SLL_P_CAN as the protocol and
3213 * CAN FD frames will have ETH_P_CANFD/LINUX_SLL_P_CANFD
3214 * as the protocol, so they can be distinguished by the
3215 * protocol in the SLL header.
3217 handle->linktype = DLT_LINUX_SLL;
3220 #ifndef ARPHRD_IEEE802_TR
3221 #define ARPHRD_IEEE802_TR 800 /* From Linux 2.4 */
3223 case ARPHRD_IEEE802_TR:
3224 case ARPHRD_IEEE802:
3225 handle->linktype = DLT_IEEE802;
3230 handle->linktype = DLT_ARCNET_LINUX;
3233 #ifndef ARPHRD_FDDI /* From Linux 2.2.13 */
3234 #define ARPHRD_FDDI 774
3237 handle->linktype = DLT_FDDI;
3241 #ifndef ARPHRD_ATM /* FIXME: How to #include this? */
3242 #define ARPHRD_ATM 19
3246 * The Classical IP implementation in ATM for Linux
3247 * supports both what RFC 1483 calls "LLC Encapsulation",
3248 * in which each packet has an LLC header, possibly
3249 * with a SNAP header as well, prepended to it, and
3250 * what RFC 1483 calls "VC Based Multiplexing", in which
3251 * different virtual circuits carry different network
3252 * layer protocols, and no header is prepended to packets.
3254 * They both have an ARPHRD_ type of ARPHRD_ATM, so
3255 * you can't use the ARPHRD_ type to find out whether
3256 * captured packets will have an LLC header, and,
3257 * while there's a socket ioctl to *set* the encapsulation
3258 * type, there's no ioctl to *get* the encapsulation type.
3262 * programs that dissect Linux Classical IP frames
3263 * would have to check for an LLC header and,
3264 * depending on whether they see one or not, dissect
3265 * the frame as LLC-encapsulated or as raw IP (I
3266 * don't know whether there's any traffic other than
3267 * IP that would show up on the socket, or whether
3268 * there's any support for IPv6 in the Linux
3269 * Classical IP code);
3271 * filter expressions would have to compile into
3272 * code that checks for an LLC header and does
3275 * Both of those are a nuisance - and, at least on systems
3276 * that support PF_PACKET sockets, we don't have to put
3277 * up with those nuisances; instead, we can just capture
3278 * in cooked mode. That's what we'll do, if we can.
3279 * Otherwise, we'll just fail.
3282 handle->linktype = DLT_LINUX_SLL;
3284 handle->linktype = -1;
3287 #ifndef ARPHRD_IEEE80211 /* From Linux 2.4.6 */
3288 #define ARPHRD_IEEE80211 801
3290 case ARPHRD_IEEE80211:
3291 handle->linktype = DLT_IEEE802_11;
3294 #ifndef ARPHRD_IEEE80211_PRISM /* From Linux 2.4.18 */
3295 #define ARPHRD_IEEE80211_PRISM 802
3297 case ARPHRD_IEEE80211_PRISM:
3298 handle->linktype = DLT_PRISM_HEADER;
3301 #ifndef ARPHRD_IEEE80211_RADIOTAP /* new */
3302 #define ARPHRD_IEEE80211_RADIOTAP 803
3304 case ARPHRD_IEEE80211_RADIOTAP:
3305 handle->linktype = DLT_IEEE802_11_RADIO;
3310 * Some PPP code in the kernel supplies no link-layer
3311 * header whatsoever to PF_PACKET sockets; other PPP
3312 * code supplies PPP link-layer headers ("syncppp.c");
3313 * some PPP code might supply random link-layer
3314 * headers (PPP over ISDN - there's code in Ethereal,
3315 * for example, to cope with PPP-over-ISDN captures
3316 * with which the Ethereal developers have had to cope,
3317 * heuristically trying to determine which of the
3318 * oddball link-layer headers particular packets have).
3320 * As such, we just punt, and run all PPP interfaces
3321 * in cooked mode, if we can; otherwise, we just treat
3322 * it as DLT_RAW, for now - if somebody needs to capture,
3323 * on a 2.0[.x] kernel, on PPP devices that supply a
3324 * link-layer header, they'll have to add code here to
3325 * map to the appropriate DLT_ type (possibly adding a
3326 * new DLT_ type, if necessary).
3329 handle->linktype = DLT_LINUX_SLL;
3332 * XXX - handle ISDN types here? We can't fall
3333 * back on cooked sockets, so we'd have to
3334 * figure out from the device name what type of
3335 * link-layer encapsulation it's using, and map
3336 * that to an appropriate DLT_ value, meaning
3337 * we'd map "isdnN" devices to DLT_RAW (they
3338 * supply raw IP packets with no link-layer
3339 * header) and "isdY" devices to a new DLT_I4L_IP
3340 * type that has only an Ethernet packet type as
3341 * a link-layer header.
3343 * But sometimes we seem to get random crap
3344 * in the link-layer header when capturing on
3347 handle->linktype = DLT_RAW;
3351 #ifndef ARPHRD_CISCO
3352 #define ARPHRD_CISCO 513 /* previously ARPHRD_HDLC */
3355 handle->linktype = DLT_C_HDLC;
3358 /* Not sure if this is correct for all tunnels, but it
3362 #define ARPHRD_SIT 776 /* From Linux 2.2.13 */
3370 #ifndef ARPHRD_RAWHDLC
3371 #define ARPHRD_RAWHDLC 518
3373 case ARPHRD_RAWHDLC:
3375 #define ARPHRD_DLCI 15
3379 * XXX - should some of those be mapped to DLT_LINUX_SLL
3380 * instead? Should we just map all of them to DLT_LINUX_SLL?
3382 handle->linktype = DLT_RAW;
3386 #define ARPHRD_FRAD 770
3389 handle->linktype = DLT_FRELAY;
3392 case ARPHRD_LOCALTLK:
3393 handle->linktype = DLT_LTALK;
3398 * RFC 4338 defines an encapsulation for IP and ARP
3399 * packets that's compatible with the RFC 2625
3400 * encapsulation, but that uses a different ARP
3401 * hardware type and hardware addresses. That
3402 * ARP hardware type is 18; Linux doesn't define
3403 * any ARPHRD_ value as 18, but if it ever officially
3404 * supports RFC 4338-style IP-over-FC, it should define
3407 * For now, we map it to DLT_IP_OVER_FC, in the hopes
3408 * that this will encourage its use in the future,
3409 * should Linux ever officially support RFC 4338-style
3412 handle->linktype = DLT_IP_OVER_FC;
3416 #define ARPHRD_FCPP 784
3420 #define ARPHRD_FCAL 785
3424 #define ARPHRD_FCPL 786
3427 #ifndef ARPHRD_FCFABRIC
3428 #define ARPHRD_FCFABRIC 787
3430 case ARPHRD_FCFABRIC:
3432 * Back in 2002, Donald Lee at Cray wanted a DLT_ for
3435 * http://www.mail-archive.com/tcpdump-workers@sandelman.ottawa.on.ca/msg01043.html
3437 * and one was assigned.
3439 * In a later private discussion (spun off from a message
3440 * on the ethereal-users list) on how to get that DLT_
3441 * value in libpcap on Linux, I ended up deciding that
3442 * the best thing to do would be to have him tweak the
3443 * driver to set the ARPHRD_ value to some ARPHRD_FCxx
3444 * type, and map all those types to DLT_IP_OVER_FC:
3446 * I've checked into the libpcap and tcpdump CVS tree
3447 * support for DLT_IP_OVER_FC. In order to use that,
3448 * you'd have to modify your modified driver to return
3449 * one of the ARPHRD_FCxxx types, in "fcLINUXfcp.c" -
3450 * change it to set "dev->type" to ARPHRD_FCFABRIC, for
3451 * example (the exact value doesn't matter, it can be
3452 * any of ARPHRD_FCPP, ARPHRD_FCAL, ARPHRD_FCPL, or
3455 * 11 years later, Christian Svensson wanted to map
3456 * various ARPHRD_ values to DLT_FC_2 and
3457 * DLT_FC_2_WITH_FRAME_DELIMS for raw Fibre Channel
3460 * https://github.com/mcr/libpcap/pull/29
3462 * There doesn't seem to be any network drivers that uses
3463 * any of the ARPHRD_FC* values for IP-over-FC, and
3464 * it's not exactly clear what the "Dummy types for non
3465 * ARP hardware" are supposed to mean (link-layer
3466 * header type? Physical network type?), so it's
3467 * not exactly clear why the ARPHRD_FC* types exist
3468 * in the first place.
3470 * For now, we map them to DLT_FC_2, and provide an
3471 * option of DLT_FC_2_WITH_FRAME_DELIMS, as well as
3472 * DLT_IP_OVER_FC just in case there's some old
3473 * driver out there that uses one of those types for
3474 * IP-over-FC on which somebody wants to capture
3477 handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 3);
3479 * If that fails, just leave the list empty.
3481 if (handle->dlt_list != NULL) {
3482 handle->dlt_list[0] = DLT_FC_2;
3483 handle->dlt_list[1] = DLT_FC_2_WITH_FRAME_DELIMS;
3484 handle->dlt_list[2] = DLT_IP_OVER_FC;
3485 handle->dlt_count = 3;
3487 handle->linktype = DLT_FC_2;
3491 #define ARPHRD_IRDA 783
3494 /* Don't expect IP packet out of this interfaces... */
3495 handle->linktype = DLT_LINUX_IRDA;
3496 /* We need to save packet direction for IrDA decoding,
3497 * so let's use "Linux-cooked" mode. Jean II
3499 * XXX - this is handled in activate_new(). */
3500 /* handlep->cooked = 1; */
3503 /* ARPHRD_LAPD is unofficial and randomly allocated, if reallocation
3504 * is needed, please report it to <daniele@orlandi.com> */
3506 #define ARPHRD_LAPD 8445
3509 /* Don't expect IP packet out of this interfaces... */
3510 handle->linktype = DLT_LINUX_LAPD;
3514 #define ARPHRD_NONE 0xFFFE
3518 * No link-layer header; packets are just IP
3519 * packets, so use DLT_RAW.
3521 handle->linktype = DLT_RAW;
3524 #ifndef ARPHRD_IEEE802154
3525 #define ARPHRD_IEEE802154 804
3527 case ARPHRD_IEEE802154:
3528 handle->linktype = DLT_IEEE802_15_4_NOFCS;
3531 #ifndef ARPHRD_NETLINK
3532 #define ARPHRD_NETLINK 824
3534 case ARPHRD_NETLINK:
3535 handle->linktype = DLT_NETLINK;
3537 * We need to use cooked mode, so that in sll_protocol we
3538 * pick up the netlink protocol type such as NETLINK_ROUTE,
3539 * NETLINK_GENERIC, NETLINK_FIB_LOOKUP, etc.
3541 * XXX - this is handled in activate_new().
3543 /* handlep->cooked = 1; */
3546 #ifndef ARPHRD_VSOCKMON
3547 #define ARPHRD_VSOCKMON 826
3549 case ARPHRD_VSOCKMON:
3550 handle->linktype = DLT_VSOCK;
3554 handle->linktype = -1;
3559 /* ===== Functions to interface to the newer kernels ================== */
3562 * Try to open a packet socket using the new kernel PF_PACKET interface.
3563 * Returns 1 on success, 0 on an error that means the new interface isn't
3564 * present (so the old SOCK_PACKET interface should be tried), and a
3565 * PCAP_ERROR_ value on an error that means that the old mechanism won't
3566 * work either (so it shouldn't be tried).
3569 activate_new(pcap_t *handle)
3571 #ifdef HAVE_PF_PACKET_SOCKETS
3572 struct pcap_linux *handlep = handle->priv;
3573 const char *device = handle->opt.device;
3574 int is_any_device = (strcmp(device, "any") == 0);
3575 int protocol = pcap_protocol(handle);
3576 int sock_fd = -1, arptype;
3577 #ifdef HAVE_PACKET_AUXDATA
3581 struct packet_mreq mr;
3582 #if defined(SO_BPF_EXTENSIONS) && defined(SKF_AD_VLAN_TAG_PRESENT)
3584 socklen_t len = sizeof(bpf_extensions);
3588 * Open a socket with protocol family packet. If the
3589 * "any" device was specified, we open a SOCK_DGRAM
3590 * socket for the cooked interface, otherwise we first
3591 * try a SOCK_RAW socket for the raw interface.
3593 sock_fd = is_any_device ?
3594 socket(PF_PACKET, SOCK_DGRAM, protocol) :
3595 socket(PF_PACKET, SOCK_RAW, protocol);
3597 if (sock_fd == -1) {
3598 if (errno == EINVAL || errno == EAFNOSUPPORT) {
3600 * We don't support PF_PACKET/SOCK_whatever
3601 * sockets; try the old mechanism.
3606 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
3608 if (errno == EPERM || errno == EACCES) {
3610 * You don't have permission to open the
3613 return PCAP_ERROR_PERM_DENIED;
3622 /* It seems the kernel supports the new interface. */
3623 handlep->sock_packet = 0;
3626 * Get the interface index of the loopback device.
3627 * If the attempt fails, don't fail, just set the
3628 * "handlep->lo_ifindex" to -1.
3630 * XXX - can there be more than one device that loops
3631 * packets back, i.e. devices other than "lo"? If so,
3632 * we'd need to find them all, and have an array of
3633 * indices for them, and check all of them in
3634 * "pcap_read_packet()".
3636 handlep->lo_ifindex = iface_get_id(sock_fd, "lo", handle->errbuf);
3639 * Default value for offset to align link-layer payload
3640 * on a 4-byte boundary.
3645 * What kind of frames do we have to deal with? Fall back
3646 * to cooked mode if we have an unknown interface type
3647 * or a type we know doesn't work well in raw mode.
3649 if (!is_any_device) {
3650 /* Assume for now we don't need cooked mode. */
3651 handlep->cooked = 0;
3653 if (handle->opt.rfmon) {
3655 * We were asked to turn on monitor mode.
3656 * Do so before we get the link-layer type,
3657 * because entering monitor mode could change
3658 * the link-layer type.
3660 err = enter_rfmon_mode(handle, sock_fd, device);
3668 * Nothing worked for turning monitor mode
3672 return PCAP_ERROR_RFMON_NOTSUP;
3676 * Either monitor mode has been turned on for
3677 * the device, or we've been given a different
3678 * device to open for monitor mode. If we've
3679 * been given a different device, use it.
3681 if (handlep->mondevice != NULL)
3682 device = handlep->mondevice;
3684 arptype = iface_get_arptype(sock_fd, device, handle->errbuf);
3689 map_arphrd_to_dlt(handle, sock_fd, arptype, device, 1);
3690 if (handle->linktype == -1 ||
3691 handle->linktype == DLT_LINUX_SLL ||
3692 handle->linktype == DLT_LINUX_IRDA ||
3693 handle->linktype == DLT_LINUX_LAPD ||
3694 handle->linktype == DLT_NETLINK ||
3695 (handle->linktype == DLT_EN10MB &&
3696 (strncmp("isdn", device, 4) == 0 ||
3697 strncmp("isdY", device, 4) == 0))) {
3699 * Unknown interface type (-1), or a
3700 * device we explicitly chose to run
3701 * in cooked mode (e.g., PPP devices),
3702 * or an ISDN device (whose link-layer
3703 * type we can only determine by using
3704 * APIs that may be different on different
3705 * kernels) - reopen in cooked mode.
3707 if (close(sock_fd) == -1) {
3708 pcap_fmt_errmsg_for_errno(handle->errbuf,
3709 PCAP_ERRBUF_SIZE, errno, "close");
3712 sock_fd = socket(PF_PACKET, SOCK_DGRAM, protocol);
3713 if (sock_fd == -1) {
3714 pcap_fmt_errmsg_for_errno(handle->errbuf,
3715 PCAP_ERRBUF_SIZE, errno, "socket");
3716 if (errno == EPERM || errno == EACCES) {
3718 * You don't have permission to
3721 return PCAP_ERROR_PERM_DENIED;
3729 handlep->cooked = 1;
3732 * Get rid of any link-layer type list
3733 * we allocated - this only supports cooked
3736 if (handle->dlt_list != NULL) {
3737 free(handle->dlt_list);
3738 handle->dlt_list = NULL;
3739 handle->dlt_count = 0;
3742 if (handle->linktype == -1) {
3744 * Warn that we're falling back on
3745 * cooked mode; we may want to
3746 * update "map_arphrd_to_dlt()"
3747 * to handle the new type.
3749 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
3751 "supported by libpcap - "
3752 "falling back to cooked "
3758 * IrDA capture is not a real "cooked" capture,
3759 * it's IrLAP frames, not IP packets. The
3760 * same applies to LAPD capture.
3762 if (handle->linktype != DLT_LINUX_IRDA &&
3763 handle->linktype != DLT_LINUX_LAPD &&
3764 handle->linktype != DLT_NETLINK)
3765 handle->linktype = DLT_LINUX_SLL;
3768 handlep->ifindex = iface_get_id(sock_fd, device,
3770 if (handlep->ifindex == -1) {
3775 if ((err = iface_bind(sock_fd, handlep->ifindex,
3776 handle->errbuf, protocol)) != 1) {
3781 return 0; /* try old mechanism */
3787 if (handle->opt.rfmon) {
3789 * It doesn't support monitor mode.
3792 return PCAP_ERROR_RFMON_NOTSUP;
3796 * It uses cooked mode.
3798 handlep->cooked = 1;
3799 handle->linktype = DLT_LINUX_SLL;
3802 * We're not bound to a device.
3803 * For now, we're using this as an indication
3804 * that we can't transmit; stop doing that only
3805 * if we figure out how to transmit in cooked
3808 handlep->ifindex = -1;
3812 * Select promiscuous mode on if "promisc" is set.
3814 * Do not turn allmulti mode on if we don't select
3815 * promiscuous mode - on some devices (e.g., Orinoco
3816 * wireless interfaces), allmulti mode isn't supported
3817 * and the driver implements it by turning promiscuous
3818 * mode on, and that screws up the operation of the
3819 * card as a normal networking interface, and on no
3820 * other platform I know of does starting a non-
3821 * promiscuous capture affect which multicast packets
3822 * are received by the interface.
3826 * Hmm, how can we set promiscuous mode on all interfaces?
3827 * I am not sure if that is possible at all. For now, we
3828 * silently ignore attempts to turn promiscuous mode on
3829 * for the "any" device (so you don't have to explicitly
3830 * disable it in programs such as tcpdump).
3833 if (!is_any_device && handle->opt.promisc) {
3834 memset(&mr, 0, sizeof(mr));
3835 mr.mr_ifindex = handlep->ifindex;
3836 mr.mr_type = PACKET_MR_PROMISC;
3837 if (setsockopt(sock_fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP,
3838 &mr, sizeof(mr)) == -1) {
3839 pcap_fmt_errmsg_for_errno(handle->errbuf,
3840 PCAP_ERRBUF_SIZE, errno, "setsockopt");
3846 /* Enable auxillary data if supported and reserve room for
3847 * reconstructing VLAN headers. */
3848 #ifdef HAVE_PACKET_AUXDATA
3850 if (setsockopt(sock_fd, SOL_PACKET, PACKET_AUXDATA, &val,
3851 sizeof(val)) == -1 && errno != ENOPROTOOPT) {
3852 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
3853 errno, "setsockopt");
3857 handle->offset += VLAN_TAG_LEN;
3858 #endif /* HAVE_PACKET_AUXDATA */
3861 * This is a 2.2[.x] or later kernel (we know that
3862 * because we're not using a SOCK_PACKET socket -
3863 * PF_PACKET is supported only in 2.2 and later
3866 * We can safely pass "recvfrom()" a byte count
3867 * based on the snapshot length.
3869 * If we're in cooked mode, make the snapshot length
3870 * large enough to hold a "cooked mode" header plus
3871 * 1 byte of packet data (so we don't pass a byte
3872 * count of 0 to "recvfrom()").
3874 if (handlep->cooked) {
3875 if (handle->snapshot < SLL_HDR_LEN + 1)
3876 handle->snapshot = SLL_HDR_LEN + 1;
3878 handle->bufsize = handle->snapshot;
3881 * Set the offset at which to insert VLAN tags.
3882 * That should be the offset of the type field.
3884 switch (handle->linktype) {
3888 * The type field is after the destination and source
3891 handlep->vlan_offset = 2 * ETH_ALEN;
3896 * The type field is in the last 2 bytes of the
3897 * DLT_LINUX_SLL header.
3899 handlep->vlan_offset = SLL_HDR_LEN - 2;
3903 handlep->vlan_offset = -1; /* unknown */
3907 #if defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS)
3908 if (handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO) {
3909 int nsec_tstamps = 1;
3911 if (setsockopt(sock_fd, SOL_SOCKET, SO_TIMESTAMPNS, &nsec_tstamps, sizeof(nsec_tstamps)) < 0) {
3912 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "setsockopt: unable to set SO_TIMESTAMPNS");
3917 #endif /* defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS) */
3920 * We've succeeded. Save the socket FD in the pcap structure.
3922 handle->fd = sock_fd;
3924 #if defined(SO_BPF_EXTENSIONS) && defined(SKF_AD_VLAN_TAG_PRESENT)
3926 * Can we generate special code for VLAN checks?
3927 * (XXX - what if we need the special code but it's not supported
3928 * by the OS? Is that possible?)
3930 if (getsockopt(sock_fd, SOL_SOCKET, SO_BPF_EXTENSIONS,
3931 &bpf_extensions, &len) == 0) {
3932 if (bpf_extensions >= SKF_AD_VLAN_TAG_PRESENT) {
3934 * Yes, we can. Request that we do so.
3936 handle->bpf_codegen_flags |= BPF_SPECIAL_VLAN_HANDLING;
3939 #endif /* defined(SO_BPF_EXTENSIONS) && defined(SKF_AD_VLAN_TAG_PRESENT) */
3942 #else /* HAVE_PF_PACKET_SOCKETS */
3944 "New packet capturing interface not supported by build "
3945 "environment", PCAP_ERRBUF_SIZE);
3947 #endif /* HAVE_PF_PACKET_SOCKETS */
3950 #ifdef HAVE_PACKET_RING
3952 * Attempt to activate with memory-mapped access.
3954 * On success, returns 1, and sets *status to 0 if there are no warnings
3955 * or to a PCAP_WARNING_ code if there is a warning.
3957 * On failure due to lack of support for memory-mapped capture, returns
3960 * On error, returns -1, and sets *status to the appropriate error code;
3961 * if that is PCAP_ERROR, sets handle->errbuf to the appropriate message.
3964 activate_mmap(pcap_t *handle, int *status)
3966 struct pcap_linux *handlep = handle->priv;
3970 * Attempt to allocate a buffer to hold the contents of one
3971 * packet, for use by the oneshot callback.
3973 handlep->oneshot_buffer = malloc(handle->snapshot);
3974 if (handlep->oneshot_buffer == NULL) {
3975 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
3976 errno, "can't allocate oneshot buffer");
3977 *status = PCAP_ERROR;
3981 if (handle->opt.buffer_size == 0) {
3982 /* by default request 2M for the ring buffer */
3983 handle->opt.buffer_size = 2*1024*1024;
3985 ret = prepare_tpacket_socket(handle);
3987 free(handlep->oneshot_buffer);
3988 *status = PCAP_ERROR;
3991 ret = create_ring(handle, status);
3994 * We don't support memory-mapped capture; our caller
3995 * will fall back on reading from the socket.
3997 free(handlep->oneshot_buffer);
4002 * Error attempting to enable memory-mapped capture;
4003 * fail. create_ring() has set *status.
4005 free(handlep->oneshot_buffer);
4010 * Success. *status has been set either to 0 if there are no
4011 * warnings or to a PCAP_WARNING_ value if there is a warning.
4013 * Override some defaults and inherit the other fields from
4015 * handle->offset is used to get the current position into the rx ring.
4016 * handle->cc is used to store the ring size.
4019 switch (handlep->tp_version) {
4021 handle->read_op = pcap_read_linux_mmap_v1;
4024 handle->read_op = pcap_read_linux_mmap_v1_64;
4026 #ifdef HAVE_TPACKET2
4028 handle->read_op = pcap_read_linux_mmap_v2;
4031 #ifdef HAVE_TPACKET3
4033 handle->read_op = pcap_read_linux_mmap_v3;
4037 handle->cleanup_op = pcap_cleanup_linux_mmap;
4038 handle->setfilter_op = pcap_setfilter_linux_mmap;
4039 handle->setnonblock_op = pcap_setnonblock_mmap;
4040 handle->getnonblock_op = pcap_getnonblock_mmap;
4041 handle->oneshot_callback = pcap_oneshot_mmap;
4042 handle->selectable_fd = handle->fd;
4045 #else /* HAVE_PACKET_RING */
4047 activate_mmap(pcap_t *handle _U_, int *status _U_)
4051 #endif /* HAVE_PACKET_RING */
4053 #ifdef HAVE_PACKET_RING
4055 #if defined(HAVE_TPACKET2) || defined(HAVE_TPACKET3)
4057 * Attempt to set the socket to the specified version of the memory-mapped
4060 * Return 0 if we succeed; return 1 if we fail because that version isn't
4061 * supported; return -1 on any other error, and set handle->errbuf.
4064 init_tpacket(pcap_t *handle, int version, const char *version_str)
4066 struct pcap_linux *handlep = handle->priv;
4068 socklen_t len = sizeof(val);
4071 * Probe whether kernel supports the specified TPACKET version;
4072 * this also gets the length of the header for that version.
4074 if (getsockopt(handle->fd, SOL_PACKET, PACKET_HDRLEN, &val, &len) < 0) {
4075 if (errno == ENOPROTOOPT || errno == EINVAL)
4078 /* Failed to even find out; this is a fatal error. */
4079 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
4080 errno, "can't get %s header len on packet socket",
4084 handlep->tp_hdrlen = val;
4087 if (setsockopt(handle->fd, SOL_PACKET, PACKET_VERSION, &val,
4089 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
4090 errno, "can't activate %s on packet socket", version_str);
4093 handlep->tp_version = version;
4095 /* Reserve space for VLAN tag reconstruction */
4097 if (setsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE, &val,
4099 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
4100 errno, "can't set up reserve on packet socket");
4106 #endif /* defined HAVE_TPACKET2 || defined HAVE_TPACKET3 */
4109 * If the instruction set for which we're compiling has both 32-bit
4110 * and 64-bit versions, and Linux support for the 64-bit version
4111 * predates TPACKET_V2, define ISA_64_BIT as the .machine value
4112 * you get from uname() for the 64-bit version. Otherwise, leave
4113 * it undefined. (This includes ARM, which has a 64-bit version,
4114 * but Linux support for it appeared well after TPACKET_V2 support
4115 * did, so there should never be a case where 32-bit ARM code is
4116 * running o a 64-bit kernel that only supports TPACKET_V1.)
4118 * If we've omitted your favorite such architecture, please contribute
4119 * a patch. (No patch is needed for architectures that are 32-bit-only
4120 * or for which Linux has no support for 32-bit userland - or for which,
4121 * as noted, 64-bit support appeared in Linux after TPACKET_V2 support
4124 #if defined(__i386__)
4125 #define ISA_64_BIT "x86_64"
4126 #elif defined(__ppc__)
4127 #define ISA_64_BIT "ppc64"
4128 #elif defined(__sparc__)
4129 #define ISA_64_BIT "sparc64"
4130 #elif defined(__s390__)
4131 #define ISA_64_BIT "s390x"
4132 #elif defined(__mips__)
4133 #define ISA_64_BIT "mips64"
4134 #elif defined(__hppa__)
4135 #define ISA_64_BIT "parisc64"
4139 * Attempt to set the socket to version 3 of the memory-mapped header and,
4140 * if that fails because version 3 isn't supported, attempt to fall
4141 * back to version 2. If version 2 isn't supported, just leave it at
4144 * Return 1 if we succeed or if we fail because neither version 2 nor 3 is
4145 * supported; return -1 on any other error, and set handle->errbuf.
4148 prepare_tpacket_socket(pcap_t *handle)
4150 struct pcap_linux *handlep = handle->priv;
4151 #if defined(HAVE_TPACKET2) || defined(HAVE_TPACKET3)
4155 #ifdef HAVE_TPACKET3
4157 * Try setting the version to TPACKET_V3.
4159 * The only mode in which buffering is done on PF_PACKET
4160 * sockets, so that packets might not be delivered
4161 * immediately, is TPACKET_V3 mode.
4163 * The buffering cannot be disabled in that mode, so
4164 * if the user has requested immediate mode, we don't
4167 if (!handle->opt.immediate) {
4168 ret = init_tpacket(handle, TPACKET_V3, "TPACKET_V3");
4177 * We failed for some reason other than "the
4178 * kernel doesn't support TPACKET_V3".
4183 #endif /* HAVE_TPACKET3 */
4185 #ifdef HAVE_TPACKET2
4187 * Try setting the version to TPACKET_V2.
4189 ret = init_tpacket(handle, TPACKET_V2, "TPACKET_V2");
4198 * We failed for some reason other than "the
4199 * kernel doesn't support TPACKET_V2".
4203 #endif /* HAVE_TPACKET2 */
4206 * OK, we're using TPACKET_V1, as that's all the kernel supports.
4208 handlep->tp_version = TPACKET_V1;
4209 handlep->tp_hdrlen = sizeof(struct tpacket_hdr);
4213 * 32-bit userspace + 64-bit kernel + TPACKET_V1 are not compatible with
4214 * each other due to platform-dependent data type size differences.
4216 * If we have a 32-bit userland and a 64-bit kernel, use an
4217 * internally-defined TPACKET_V1_64, with which we use a 64-bit
4218 * version of the data structures.
4220 if (sizeof(long) == 4) {
4222 * This is 32-bit code.
4224 struct utsname utsname;
4226 if (uname(&utsname) == -1) {
4230 pcap_fmt_errmsg_for_errno(handle->errbuf,
4231 PCAP_ERRBUF_SIZE, errno, "uname failed");
4234 if (strcmp(utsname.machine, ISA_64_BIT) == 0) {
4236 * uname() tells us the machine is 64-bit,
4237 * so we presumably have a 64-bit kernel.
4239 * XXX - this presumes that uname() won't lie
4240 * in 32-bit code and claim that the machine
4241 * has the 32-bit version of the ISA.
4243 handlep->tp_version = TPACKET_V1_64;
4244 handlep->tp_hdrlen = sizeof(struct tpacket_hdr_64);
4252 #define MAX(a,b) ((a)>(b)?(a):(b))
4255 * Attempt to set up memory-mapped access.
4257 * On success, returns 1, and sets *status to 0 if there are no warnings
4258 * or to a PCAP_WARNING_ code if there is a warning.
4260 * On failure due to lack of support for memory-mapped capture, returns
4263 * On error, returns -1, and sets *status to the appropriate error code;
4264 * if that is PCAP_ERROR, sets handle->errbuf to the appropriate message.
4267 create_ring(pcap_t *handle, int *status)
4269 struct pcap_linux *handlep = handle->priv;
4270 unsigned i, j, frames_per_block;
4271 #ifdef HAVE_TPACKET3
4273 * For sockets using TPACKET_V1 or TPACKET_V2, the extra
4274 * stuff at the end of a struct tpacket_req3 will be
4275 * ignored, so this is OK even for those sockets.
4277 struct tpacket_req3 req;
4279 struct tpacket_req req;
4282 unsigned int sk_type, tp_reserve, maclen, tp_hdrlen, netoff, macoff;
4283 unsigned int frame_size;
4286 * Start out assuming no warnings or errors.
4290 switch (handlep->tp_version) {
4294 #ifdef HAVE_TPACKET2
4297 /* Note that with large snapshot length (say 256K, which is
4298 * the default for recent versions of tcpdump, Wireshark,
4299 * TShark, dumpcap or 64K, the value that "-s 0" has given for
4300 * a long time with tcpdump), if we use the snapshot
4301 * length to calculate the frame length, only a few frames
4302 * will be available in the ring even with pretty
4303 * large ring size (and a lot of memory will be unused).
4305 * Ideally, we should choose a frame length based on the
4306 * minimum of the specified snapshot length and the maximum
4307 * packet size. That's not as easy as it sounds; consider,
4308 * for example, an 802.11 interface in monitor mode, where
4309 * the frame would include a radiotap header, where the
4310 * maximum radiotap header length is device-dependent.
4312 * So, for now, we just do this for Ethernet devices, where
4313 * there's no metadata header, and the link-layer header is
4314 * fixed length. We can get the maximum packet size by
4315 * adding 18, the Ethernet header length plus the CRC length
4316 * (just in case we happen to get the CRC in the packet), to
4317 * the MTU of the interface; we fetch the MTU in the hopes
4318 * that it reflects support for jumbo frames. (Even if the
4319 * interface is just being used for passive snooping, the
4320 * driver might set the size of buffers in the receive ring
4321 * based on the MTU, so that the MTU limits the maximum size
4322 * of packets that we can receive.)
4324 * If segmentation/fragmentation or receive offload are
4325 * enabled, we can get reassembled/aggregated packets larger
4326 * than MTU, but bounded to 65535 plus the Ethernet overhead,
4327 * due to kernel and protocol constraints */
4328 frame_size = handle->snapshot;
4329 if (handle->linktype == DLT_EN10MB) {
4330 unsigned int max_frame_len;
4334 mtu = iface_get_mtu(handle->fd, handle->opt.device,
4337 *status = PCAP_ERROR;
4340 offload = iface_get_offload(handle);
4341 if (offload == -1) {
4342 *status = PCAP_ERROR;
4346 max_frame_len = MAX(mtu, 65535);
4348 max_frame_len = mtu;
4349 max_frame_len += 18;
4351 if (frame_size > max_frame_len)
4352 frame_size = max_frame_len;
4355 /* NOTE: calculus matching those in tpacket_rcv()
4356 * in linux-2.6/net/packet/af_packet.c
4358 len = sizeof(sk_type);
4359 if (getsockopt(handle->fd, SOL_SOCKET, SO_TYPE, &sk_type,
4361 pcap_fmt_errmsg_for_errno(handle->errbuf,
4362 PCAP_ERRBUF_SIZE, errno, "getsockopt");
4363 *status = PCAP_ERROR;
4366 #ifdef PACKET_RESERVE
4367 len = sizeof(tp_reserve);
4368 if (getsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE,
4369 &tp_reserve, &len) < 0) {
4370 if (errno != ENOPROTOOPT) {
4372 * ENOPROTOOPT means "kernel doesn't support
4373 * PACKET_RESERVE", in which case we fall back
4376 pcap_fmt_errmsg_for_errno(handle->errbuf,
4377 PCAP_ERRBUF_SIZE, errno, "getsockopt");
4378 *status = PCAP_ERROR;
4381 tp_reserve = 0; /* older kernel, reserve not supported */
4384 tp_reserve = 0; /* older kernel, reserve not supported */
4386 maclen = (sk_type == SOCK_DGRAM) ? 0 : MAX_LINKHEADER_SIZE;
4387 /* XXX: in the kernel maclen is calculated from
4388 * LL_ALLOCATED_SPACE(dev) and vnet_hdr.hdr_len
4389 * in: packet_snd() in linux-2.6/net/packet/af_packet.c
4390 * then packet_alloc_skb() in linux-2.6/net/packet/af_packet.c
4391 * then sock_alloc_send_pskb() in linux-2.6/net/core/sock.c
4392 * but I see no way to get those sizes in userspace,
4393 * like for instance with an ifreq ioctl();
4394 * the best thing I've found so far is MAX_HEADER in
4395 * the kernel part of linux-2.6/include/linux/netdevice.h
4396 * which goes up to 128+48=176; since pcap-linux.c
4397 * defines a MAX_LINKHEADER_SIZE of 256 which is
4398 * greater than that, let's use it.. maybe is it even
4399 * large enough to directly replace macoff..
4401 tp_hdrlen = TPACKET_ALIGN(handlep->tp_hdrlen) + sizeof(struct sockaddr_ll) ;
4402 netoff = TPACKET_ALIGN(tp_hdrlen + (maclen < 16 ? 16 : maclen)) + tp_reserve;
4403 /* NOTE: AFAICS tp_reserve may break the TPACKET_ALIGN
4404 * of netoff, which contradicts
4405 * linux-2.6/Documentation/networking/packet_mmap.txt
4407 * "- Gap, chosen so that packet data (Start+tp_net)
4408 * aligns to TPACKET_ALIGNMENT=16"
4410 /* NOTE: in linux-2.6/include/linux/skbuff.h:
4411 * "CPUs often take a performance hit
4412 * when accessing unaligned memory locations"
4414 macoff = netoff - maclen;
4415 req.tp_frame_size = TPACKET_ALIGN(macoff + frame_size);
4417 * Round the buffer size up to a multiple of the
4418 * frame size (rather than rounding down, which
4419 * would give a buffer smaller than our caller asked
4420 * for, and possibly give zero frames if the requested
4421 * buffer size is too small for one frame).
4423 req.tp_frame_nr = (handle->opt.buffer_size + req.tp_frame_size - 1)/req.tp_frame_size;
4426 #ifdef HAVE_TPACKET3
4428 /* The "frames" for this are actually buffers that
4429 * contain multiple variable-sized frames.
4431 * We pick a "frame" size of MAXIMUM_SNAPLEN to leave
4432 * enough room for at least one reasonably-sized packet
4433 * in the "frame". */
4434 req.tp_frame_size = MAXIMUM_SNAPLEN;
4436 * Round the buffer size up to a multiple of the
4437 * "frame" size (rather than rounding down, which
4438 * would give a buffer smaller than our caller asked
4439 * for, and possibly give zero "frames" if the requested
4440 * buffer size is too small for one "frame").
4442 req.tp_frame_nr = (handle->opt.buffer_size + req.tp_frame_size - 1)/req.tp_frame_size;
4446 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
4447 "Internal error: unknown TPACKET_ value %u",
4448 handlep->tp_version);
4449 *status = PCAP_ERROR;
4453 /* compute the minumum block size that will handle this frame.
4454 * The block has to be page size aligned.
4455 * The max block size allowed by the kernel is arch-dependent and
4456 * it's not explicitly checked here. */
4457 req.tp_block_size = getpagesize();
4458 while (req.tp_block_size < req.tp_frame_size)
4459 req.tp_block_size <<= 1;
4461 frames_per_block = req.tp_block_size/req.tp_frame_size;
4464 * PACKET_TIMESTAMP was added after linux/net_tstamp.h was,
4465 * so we check for PACKET_TIMESTAMP. We check for
4466 * linux/net_tstamp.h just in case a system somehow has
4467 * PACKET_TIMESTAMP but not linux/net_tstamp.h; that might
4470 * SIOCSHWTSTAMP was introduced in the patch that introduced
4471 * linux/net_tstamp.h, so we don't bother checking whether
4472 * SIOCSHWTSTAMP is defined (if your Linux system has
4473 * linux/net_tstamp.h but doesn't define SIOCSHWTSTAMP, your
4474 * Linux system is badly broken).
4476 #if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
4478 * If we were told to do so, ask the kernel and the driver
4479 * to use hardware timestamps.
4481 * Hardware timestamps are only supported with mmapped
4484 if (handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER ||
4485 handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER_UNSYNCED) {
4486 struct hwtstamp_config hwconfig;
4491 * Ask for hardware time stamps on all packets,
4492 * including transmitted packets.
4494 memset(&hwconfig, 0, sizeof(hwconfig));
4495 hwconfig.tx_type = HWTSTAMP_TX_ON;
4496 hwconfig.rx_filter = HWTSTAMP_FILTER_ALL;
4498 memset(&ifr, 0, sizeof(ifr));
4499 strlcpy(ifr.ifr_name, handle->opt.device, sizeof(ifr.ifr_name));
4500 ifr.ifr_data = (void *)&hwconfig;
4502 if (ioctl(handle->fd, SIOCSHWTSTAMP, &ifr) < 0) {
4507 * Treat this as an error, as the
4508 * user should try to run this
4509 * with the appropriate privileges -
4510 * and, if they can't, shouldn't
4511 * try requesting hardware time stamps.
4513 *status = PCAP_ERROR_PERM_DENIED;
4519 * Treat this as a warning, as the
4520 * only way to fix the warning is to
4521 * get an adapter that supports hardware
4522 * time stamps for *all* packets.
4523 * (ERANGE means "we support hardware
4524 * time stamps, but for packets matching
4525 * that particular filter", so it means
4526 * "we don't support hardware time stamps
4527 * for all incoming packets" here.)
4529 * We'll just fall back on the standard
4532 *status = PCAP_WARNING_TSTAMP_TYPE_NOTSUP;
4536 pcap_fmt_errmsg_for_errno(handle->errbuf,
4537 PCAP_ERRBUF_SIZE, errno,
4538 "SIOCSHWTSTAMP failed");
4539 *status = PCAP_ERROR;
4544 * Well, that worked. Now specify the type of
4545 * hardware time stamp we want for this
4548 if (handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER) {
4550 * Hardware timestamp, synchronized
4551 * with the system clock.
4553 timesource = SOF_TIMESTAMPING_SYS_HARDWARE;
4556 * PCAP_TSTAMP_ADAPTER_UNSYNCED - hardware
4557 * timestamp, not synchronized with the
4560 timesource = SOF_TIMESTAMPING_RAW_HARDWARE;
4562 if (setsockopt(handle->fd, SOL_PACKET, PACKET_TIMESTAMP,
4563 (void *)×ource, sizeof(timesource))) {
4564 pcap_fmt_errmsg_for_errno(handle->errbuf,
4565 PCAP_ERRBUF_SIZE, errno,
4566 "can't set PACKET_TIMESTAMP");
4567 *status = PCAP_ERROR;
4572 #endif /* HAVE_LINUX_NET_TSTAMP_H && PACKET_TIMESTAMP */
4574 /* ask the kernel to create the ring */
4576 req.tp_block_nr = req.tp_frame_nr / frames_per_block;
4578 /* req.tp_frame_nr is requested to match frames_per_block*req.tp_block_nr */
4579 req.tp_frame_nr = req.tp_block_nr * frames_per_block;
4581 #ifdef HAVE_TPACKET3
4582 /* timeout value to retire block - use the configured buffering timeout, or default if <0. */
4583 req.tp_retire_blk_tov = (handlep->timeout>=0)?handlep->timeout:0;
4584 /* private data not used */
4585 req.tp_sizeof_priv = 0;
4586 /* Rx ring - feature request bits - none (rxhash will not be filled) */
4587 req.tp_feature_req_word = 0;
4590 if (setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING,
4591 (void *) &req, sizeof(req))) {
4592 if ((errno == ENOMEM) && (req.tp_block_nr > 1)) {
4594 * Memory failure; try to reduce the requested ring
4597 * We used to reduce this by half -- do 5% instead.
4598 * That may result in more iterations and a longer
4599 * startup, but the user will be much happier with
4600 * the resulting buffer size.
4602 if (req.tp_frame_nr < 20)
4603 req.tp_frame_nr -= 1;
4605 req.tp_frame_nr -= req.tp_frame_nr/20;
4608 if (errno == ENOPROTOOPT) {
4610 * We don't have ring buffer support in this kernel.
4614 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
4615 errno, "can't create rx ring on packet socket");
4616 *status = PCAP_ERROR;
4620 /* memory map the rx ring */
4621 handlep->mmapbuflen = req.tp_block_nr * req.tp_block_size;
4622 handlep->mmapbuf = mmap(0, handlep->mmapbuflen,
4623 PROT_READ|PROT_WRITE, MAP_SHARED, handle->fd, 0);
4624 if (handlep->mmapbuf == MAP_FAILED) {
4625 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
4626 errno, "can't mmap rx ring");
4628 /* clear the allocated ring on error*/
4629 destroy_ring(handle);
4630 *status = PCAP_ERROR;
4634 /* allocate a ring for each frame header pointer*/
4635 handle->cc = req.tp_frame_nr;
4636 handle->buffer = malloc(handle->cc * sizeof(union thdr *));
4637 if (!handle->buffer) {
4638 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
4639 errno, "can't allocate ring of frame headers");
4641 destroy_ring(handle);
4642 *status = PCAP_ERROR;
4646 /* fill the header ring with proper frame ptr*/
4648 for (i=0; i<req.tp_block_nr; ++i) {
4649 void *base = &handlep->mmapbuf[i*req.tp_block_size];
4650 for (j=0; j<frames_per_block; ++j, ++handle->offset) {
4651 RING_GET_CURRENT_FRAME(handle) = base;
4652 base += req.tp_frame_size;
4656 handle->bufsize = req.tp_frame_size;
4661 /* free all ring related resources*/
4663 destroy_ring(pcap_t *handle)
4665 struct pcap_linux *handlep = handle->priv;
4667 /* tell the kernel to destroy the ring*/
4668 struct tpacket_req req;
4669 memset(&req, 0, sizeof(req));
4670 /* do not test for setsockopt failure, as we can't recover from any error */
4671 (void)setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING,
4672 (void *) &req, sizeof(req));
4674 /* if ring is mapped, unmap it*/
4675 if (handlep->mmapbuf) {
4676 /* do not test for mmap failure, as we can't recover from any error */
4677 (void)munmap(handlep->mmapbuf, handlep->mmapbuflen);
4678 handlep->mmapbuf = NULL;
4683 * Special one-shot callback, used for pcap_next() and pcap_next_ex(),
4684 * for Linux mmapped capture.
4686 * The problem is that pcap_next() and pcap_next_ex() expect the packet
4687 * data handed to the callback to be valid after the callback returns,
4688 * but pcap_read_linux_mmap() has to release that packet as soon as
4689 * the callback returns (otherwise, the kernel thinks there's still
4690 * at least one unprocessed packet available in the ring, so a select()
4691 * will immediately return indicating that there's data to process), so,
4692 * in the callback, we have to make a copy of the packet.
4694 * Yes, this means that, if the capture is using the ring buffer, using
4695 * pcap_next() or pcap_next_ex() requires more copies than using
4696 * pcap_loop() or pcap_dispatch(). If that bothers you, don't use
4697 * pcap_next() or pcap_next_ex().
4700 pcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h,
4701 const u_char *bytes)
4703 struct oneshot_userdata *sp = (struct oneshot_userdata *)user;
4704 pcap_t *handle = sp->pd;
4705 struct pcap_linux *handlep = handle->priv;
4708 memcpy(handlep->oneshot_buffer, bytes, h->caplen);
4709 *sp->pkt = handlep->oneshot_buffer;
4713 pcap_cleanup_linux_mmap( pcap_t *handle )
4715 struct pcap_linux *handlep = handle->priv;
4717 destroy_ring(handle);
4718 if (handlep->oneshot_buffer != NULL) {
4719 free(handlep->oneshot_buffer);
4720 handlep->oneshot_buffer = NULL;
4722 pcap_cleanup_linux(handle);
4727 pcap_getnonblock_mmap(pcap_t *handle)
4729 struct pcap_linux *handlep = handle->priv;
4731 /* use negative value of timeout to indicate non blocking ops */
4732 return (handlep->timeout<0);
4736 pcap_setnonblock_mmap(pcap_t *handle, int nonblock)
4738 struct pcap_linux *handlep = handle->priv;
4741 * Set the file descriptor to non-blocking mode, as we use
4742 * it for sending packets.
4744 if (pcap_setnonblock_fd(handle, nonblock) == -1)
4748 * Map each value to their corresponding negation to
4749 * preserve the timeout value provided with pcap_set_timeout.
4752 if (handlep->timeout >= 0) {
4754 * Indicate that we're switching to
4755 * non-blocking mode.
4757 handlep->timeout = ~handlep->timeout;
4760 if (handlep->timeout < 0) {
4761 handlep->timeout = ~handlep->timeout;
4764 /* Update the timeout to use in poll(). */
4765 set_poll_timeout(handlep);
4770 * Get the status field of the ring buffer frame at a specified offset.
4773 pcap_get_ring_frame_status(pcap_t *handle, int offset)
4775 struct pcap_linux *handlep = handle->priv;
4778 h.raw = RING_GET_FRAME_AT(handle, offset);
4779 switch (handlep->tp_version) {
4781 return (h.h1->tp_status);
4784 return (h.h1_64->tp_status);
4786 #ifdef HAVE_TPACKET2
4788 return (h.h2->tp_status);
4791 #ifdef HAVE_TPACKET3
4793 return (h.h3->hdr.bh1.block_status);
4797 /* This should not happen. */
4806 * Block waiting for frames to be available.
4808 static int pcap_wait_for_frames_mmap(pcap_t *handle)
4810 struct pcap_linux *handlep = handle->priv;
4812 struct pollfd pollinfo;
4815 pollinfo.fd = handle->fd;
4816 pollinfo.events = POLLIN;
4820 * Yes, we do this even in non-blocking mode, as it's
4821 * the only way to get error indications from a
4824 * The timeout is 0 in non-blocking mode, so poll()
4825 * returns immediately.
4827 ret = poll(&pollinfo, 1, handlep->poll_timeout);
4828 if (ret < 0 && errno != EINTR) {
4829 pcap_fmt_errmsg_for_errno(handle->errbuf,
4830 PCAP_ERRBUF_SIZE, errno,
4831 "can't poll on packet socket");
4833 } else if (ret > 0 &&
4834 (pollinfo.revents & (POLLHUP|POLLRDHUP|POLLERR|POLLNVAL))) {
4836 * There's some indication other than
4837 * "you can read on this descriptor" on
4840 if (pollinfo.revents & (POLLHUP | POLLRDHUP)) {
4841 pcap_snprintf(handle->errbuf,
4843 "Hangup on packet socket");
4846 if (pollinfo.revents & POLLERR) {
4848 * A recv() will give us the actual error code.
4850 * XXX - make the socket non-blocking?
4852 if (recv(handle->fd, &c, sizeof c,
4854 continue; /* what, no error? */
4855 if (errno == ENETDOWN) {
4857 * The device on which we're
4858 * capturing went away.
4860 * XXX - we should really return
4861 * PCAP_ERROR_IFACE_NOT_UP, but
4862 * pcap_dispatch() etc. aren't
4863 * defined to return that.
4865 pcap_snprintf(handle->errbuf,
4867 "The interface went down");
4869 pcap_fmt_errmsg_for_errno(handle->errbuf,
4870 PCAP_ERRBUF_SIZE, errno,
4871 "Error condition on packet socket");
4875 if (pollinfo.revents & POLLNVAL) {
4876 pcap_snprintf(handle->errbuf,
4878 "Invalid polling request on packet socket");
4882 /* check for break loop condition on interrupted syscall*/
4883 if (handle->break_loop) {
4884 handle->break_loop = 0;
4885 return PCAP_ERROR_BREAK;
4891 /* handle a single memory mapped packet */
4892 static int pcap_handle_packet_mmap(
4894 pcap_handler callback,
4896 unsigned char *frame,
4897 unsigned int tp_len,
4898 unsigned int tp_mac,
4899 unsigned int tp_snaplen,
4900 unsigned int tp_sec,
4901 unsigned int tp_usec,
4902 int tp_vlan_tci_valid,
4906 struct pcap_linux *handlep = handle->priv;
4908 struct sockaddr_ll *sll;
4909 struct pcap_pkthdr pcaphdr;
4910 unsigned int snaplen = tp_snaplen;
4912 /* perform sanity check on internal offset. */
4913 if (tp_mac + tp_snaplen > handle->bufsize) {
4914 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
4915 "corrupted frame on kernel ring mac "
4916 "offset %u + caplen %u > frame len %d",
4917 tp_mac, tp_snaplen, handle->bufsize);
4921 /* run filter on received packet
4922 * If the kernel filtering is enabled we need to run the
4923 * filter until all the frames present into the ring
4924 * at filter creation time are processed.
4925 * In this case, blocks_to_filter_in_userland is used
4926 * as a counter for the packet we need to filter.
4927 * Note: alternatively it could be possible to stop applying
4928 * the filter when the ring became empty, but it can possibly
4929 * happen a lot later... */
4930 bp = frame + tp_mac;
4932 /* if required build in place the sll header*/
4933 sll = (void *)frame + TPACKET_ALIGN(handlep->tp_hdrlen);
4934 if (handlep->cooked) {
4935 struct sll_header *hdrp;
4938 * The kernel should have left us with enough
4939 * space for an sll header; back up the packet
4940 * data pointer into that space, as that'll be
4941 * the beginning of the packet we pass to the
4947 * Let's make sure that's past the end of
4948 * the tpacket header, i.e. >=
4949 * ((u_char *)thdr + TPACKET_HDRLEN), so we
4950 * don't step on the header when we construct
4953 if (bp < (u_char *)frame +
4954 TPACKET_ALIGN(handlep->tp_hdrlen) +
4955 sizeof(struct sockaddr_ll)) {
4956 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
4957 "cooked-mode frame doesn't have room for sll header");
4962 * OK, that worked; construct the sll header.
4964 hdrp = (struct sll_header *)bp;
4965 hdrp->sll_pkttype = map_packet_type_to_sll_type(
4967 hdrp->sll_hatype = htons(sll->sll_hatype);
4968 hdrp->sll_halen = htons(sll->sll_halen);
4969 memcpy(hdrp->sll_addr, sll->sll_addr, SLL_ADDRLEN);
4970 hdrp->sll_protocol = sll->sll_protocol;
4972 snaplen += sizeof(struct sll_header);
4975 if (handlep->filter_in_userland && handle->fcode.bf_insns) {
4976 struct bpf_aux_data aux_data;
4978 aux_data.vlan_tag_present = tp_vlan_tci_valid;
4979 aux_data.vlan_tag = tp_vlan_tci & 0x0fff;
4981 if (bpf_filter_with_aux_data(handle->fcode.bf_insns,
4989 if (!linux_check_direction(handle, sll))
4992 /* get required packet info from ring header */
4993 pcaphdr.ts.tv_sec = tp_sec;
4994 pcaphdr.ts.tv_usec = tp_usec;
4995 pcaphdr.caplen = tp_snaplen;
4996 pcaphdr.len = tp_len;
4998 /* if required build in place the sll header*/
4999 if (handlep->cooked) {
5000 /* update packet len */
5001 pcaphdr.caplen += SLL_HDR_LEN;
5002 pcaphdr.len += SLL_HDR_LEN;
5005 #if defined(HAVE_TPACKET2) || defined(HAVE_TPACKET3)
5006 if (tp_vlan_tci_valid &&
5007 handlep->vlan_offset != -1 &&
5008 tp_snaplen >= (unsigned int) handlep->vlan_offset)
5010 struct vlan_tag *tag;
5013 * Move everything in the header, except the type field,
5014 * down VLAN_TAG_LEN bytes, to allow us to insert the
5015 * VLAN tag between that stuff and the type field.
5018 memmove(bp, bp + VLAN_TAG_LEN, handlep->vlan_offset);
5021 * Now insert the tag.
5023 tag = (struct vlan_tag *)(bp + handlep->vlan_offset);
5024 tag->vlan_tpid = htons(tp_vlan_tpid);
5025 tag->vlan_tci = htons(tp_vlan_tci);
5028 * Add the tag to the packet lengths.
5030 pcaphdr.caplen += VLAN_TAG_LEN;
5031 pcaphdr.len += VLAN_TAG_LEN;
5036 * The only way to tell the kernel to cut off the
5037 * packet at a snapshot length is with a filter program;
5038 * if there's no filter program, the kernel won't cut
5041 * Trim the snapshot length to be no longer than the
5042 * specified snapshot length.
5044 if (pcaphdr.caplen > (bpf_u_int32)handle->snapshot)
5045 pcaphdr.caplen = handle->snapshot;
5047 /* pass the packet to the user */
5048 callback(user, &pcaphdr, bp);
5054 pcap_read_linux_mmap_v1(pcap_t *handle, int max_packets, pcap_handler callback,
5057 struct pcap_linux *handlep = handle->priv;
5062 /* wait for frames availability.*/
5063 h.raw = RING_GET_CURRENT_FRAME(handle);
5064 if (h.h1->tp_status == TP_STATUS_KERNEL) {
5066 * The current frame is owned by the kernel; wait for
5067 * a frame to be handed to us.
5069 ret = pcap_wait_for_frames_mmap(handle);
5075 /* non-positive values of max_packets are used to require all
5076 * packets currently available in the ring */
5077 while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
5079 * Get the current ring buffer frame, and break if
5080 * it's still owned by the kernel.
5082 h.raw = RING_GET_CURRENT_FRAME(handle);
5083 if (h.h1->tp_status == TP_STATUS_KERNEL)
5086 ret = pcap_handle_packet_mmap(
5101 handlep->packets_read++;
5102 } else if (ret < 0) {
5107 * Hand this block back to the kernel, and, if we're
5108 * counting blocks that need to be filtered in userland
5109 * after having been filtered by the kernel, count
5110 * the one we've just processed.
5112 h.h1->tp_status = TP_STATUS_KERNEL;
5113 if (handlep->blocks_to_filter_in_userland > 0) {
5114 handlep->blocks_to_filter_in_userland--;
5115 if (handlep->blocks_to_filter_in_userland == 0) {
5117 * No more blocks need to be filtered
5120 handlep->filter_in_userland = 0;
5125 if (++handle->offset >= handle->cc)
5128 /* check for break loop condition*/
5129 if (handle->break_loop) {
5130 handle->break_loop = 0;
5131 return PCAP_ERROR_BREAK;
5138 pcap_read_linux_mmap_v1_64(pcap_t *handle, int max_packets, pcap_handler callback,
5141 struct pcap_linux *handlep = handle->priv;
5146 /* wait for frames availability.*/
5147 h.raw = RING_GET_CURRENT_FRAME(handle);
5148 if (h.h1_64->tp_status == TP_STATUS_KERNEL) {
5150 * The current frame is owned by the kernel; wait for
5151 * a frame to be handed to us.
5153 ret = pcap_wait_for_frames_mmap(handle);
5159 /* non-positive values of max_packets are used to require all
5160 * packets currently available in the ring */
5161 while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
5163 * Get the current ring buffer frame, and break if
5164 * it's still owned by the kernel.
5166 h.raw = RING_GET_CURRENT_FRAME(handle);
5167 if (h.h1_64->tp_status == TP_STATUS_KERNEL)
5170 ret = pcap_handle_packet_mmap(
5177 h.h1_64->tp_snaplen,
5185 handlep->packets_read++;
5186 } else if (ret < 0) {
5191 * Hand this block back to the kernel, and, if we're
5192 * counting blocks that need to be filtered in userland
5193 * after having been filtered by the kernel, count
5194 * the one we've just processed.
5196 h.h1_64->tp_status = TP_STATUS_KERNEL;
5197 if (handlep->blocks_to_filter_in_userland > 0) {
5198 handlep->blocks_to_filter_in_userland--;
5199 if (handlep->blocks_to_filter_in_userland == 0) {
5201 * No more blocks need to be filtered
5204 handlep->filter_in_userland = 0;
5209 if (++handle->offset >= handle->cc)
5212 /* check for break loop condition*/
5213 if (handle->break_loop) {
5214 handle->break_loop = 0;
5215 return PCAP_ERROR_BREAK;
5221 #ifdef HAVE_TPACKET2
5223 pcap_read_linux_mmap_v2(pcap_t *handle, int max_packets, pcap_handler callback,
5226 struct pcap_linux *handlep = handle->priv;
5231 /* wait for frames availability.*/
5232 h.raw = RING_GET_CURRENT_FRAME(handle);
5233 if (h.h2->tp_status == TP_STATUS_KERNEL) {
5235 * The current frame is owned by the kernel; wait for
5236 * a frame to be handed to us.
5238 ret = pcap_wait_for_frames_mmap(handle);
5244 /* non-positive values of max_packets are used to require all
5245 * packets currently available in the ring */
5246 while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
5248 * Get the current ring buffer frame, and break if
5249 * it's still owned by the kernel.
5251 h.raw = RING_GET_CURRENT_FRAME(handle);
5252 if (h.h2->tp_status == TP_STATUS_KERNEL)
5255 ret = pcap_handle_packet_mmap(
5264 handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO ? h.h2->tp_nsec : h.h2->tp_nsec / 1000,
5265 VLAN_VALID(h.h2, h.h2),
5267 VLAN_TPID(h.h2, h.h2));
5270 handlep->packets_read++;
5271 } else if (ret < 0) {
5276 * Hand this block back to the kernel, and, if we're
5277 * counting blocks that need to be filtered in userland
5278 * after having been filtered by the kernel, count
5279 * the one we've just processed.
5281 h.h2->tp_status = TP_STATUS_KERNEL;
5282 if (handlep->blocks_to_filter_in_userland > 0) {
5283 handlep->blocks_to_filter_in_userland--;
5284 if (handlep->blocks_to_filter_in_userland == 0) {
5286 * No more blocks need to be filtered
5289 handlep->filter_in_userland = 0;
5294 if (++handle->offset >= handle->cc)
5297 /* check for break loop condition*/
5298 if (handle->break_loop) {
5299 handle->break_loop = 0;
5300 return PCAP_ERROR_BREAK;
5305 #endif /* HAVE_TPACKET2 */
5307 #ifdef HAVE_TPACKET3
5309 pcap_read_linux_mmap_v3(pcap_t *handle, int max_packets, pcap_handler callback,
5312 struct pcap_linux *handlep = handle->priv;
5318 if (handlep->current_packet == NULL) {
5319 /* wait for frames availability.*/
5320 h.raw = RING_GET_CURRENT_FRAME(handle);
5321 if (h.h3->hdr.bh1.block_status == TP_STATUS_KERNEL) {
5323 * The current frame is owned by the kernel; wait
5324 * for a frame to be handed to us.
5326 ret = pcap_wait_for_frames_mmap(handle);
5332 h.raw = RING_GET_CURRENT_FRAME(handle);
5333 if (h.h3->hdr.bh1.block_status == TP_STATUS_KERNEL) {
5334 if (pkts == 0 && handlep->timeout == 0) {
5335 /* Block until we see a packet. */
5341 /* non-positive values of max_packets are used to require all
5342 * packets currently available in the ring */
5343 while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
5344 int packets_to_read;
5346 if (handlep->current_packet == NULL) {
5347 h.raw = RING_GET_CURRENT_FRAME(handle);
5348 if (h.h3->hdr.bh1.block_status == TP_STATUS_KERNEL)
5351 handlep->current_packet = h.raw + h.h3->hdr.bh1.offset_to_first_pkt;
5352 handlep->packets_left = h.h3->hdr.bh1.num_pkts;
5354 packets_to_read = handlep->packets_left;
5356 if (!PACKET_COUNT_IS_UNLIMITED(max_packets) &&
5357 packets_to_read > (max_packets - pkts)) {
5359 * We've been given a maximum number of packets
5360 * to process, and there are more packets in
5361 * this buffer than that. Only process enough
5362 * of them to get us up to that maximum.
5364 packets_to_read = max_packets - pkts;
5367 while (packets_to_read-- && !handle->break_loop) {
5368 struct tpacket3_hdr* tp3_hdr = (struct tpacket3_hdr*) handlep->current_packet;
5369 ret = pcap_handle_packet_mmap(
5373 handlep->current_packet,
5376 tp3_hdr->tp_snaplen,
5378 handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO ? tp3_hdr->tp_nsec : tp3_hdr->tp_nsec / 1000,
5379 VLAN_VALID(tp3_hdr, &tp3_hdr->hv1),
5380 tp3_hdr->hv1.tp_vlan_tci,
5381 VLAN_TPID(tp3_hdr, &tp3_hdr->hv1));
5384 handlep->packets_read++;
5385 } else if (ret < 0) {
5386 handlep->current_packet = NULL;
5389 handlep->current_packet += tp3_hdr->tp_next_offset;
5390 handlep->packets_left--;
5393 if (handlep->packets_left <= 0) {
5395 * Hand this block back to the kernel, and, if
5396 * we're counting blocks that need to be
5397 * filtered in userland after having been
5398 * filtered by the kernel, count the one we've
5401 h.h3->hdr.bh1.block_status = TP_STATUS_KERNEL;
5402 if (handlep->blocks_to_filter_in_userland > 0) {
5403 handlep->blocks_to_filter_in_userland--;
5404 if (handlep->blocks_to_filter_in_userland == 0) {
5406 * No more blocks need to be filtered
5409 handlep->filter_in_userland = 0;
5414 if (++handle->offset >= handle->cc)
5417 handlep->current_packet = NULL;
5420 /* check for break loop condition*/
5421 if (handle->break_loop) {
5422 handle->break_loop = 0;
5423 return PCAP_ERROR_BREAK;
5426 if (pkts == 0 && handlep->timeout == 0) {
5427 /* Block until we see a packet. */
5432 #endif /* HAVE_TPACKET3 */
5435 pcap_setfilter_linux_mmap(pcap_t *handle, struct bpf_program *filter)
5437 struct pcap_linux *handlep = handle->priv;
5442 * Don't rewrite "ret" instructions; we don't need to, as
5443 * we're not reading packets with recvmsg(), and we don't
5444 * want to, as, by not rewriting them, the kernel can avoid
5445 * copying extra data.
5447 ret = pcap_setfilter_linux_common(handle, filter, 1);
5452 * If we're filtering in userland, there's nothing to do;
5453 * the new filter will be used for the next packet.
5455 if (handlep->filter_in_userland)
5459 * We're filtering in the kernel; the packets present in
5460 * all blocks currently in the ring were already filtered
5461 * by the old filter, and so will need to be filtered in
5462 * userland by the new filter.
5464 * Get an upper bound for the number of such blocks; first,
5465 * walk the ring backward and count the free blocks.
5467 offset = handle->offset;
5469 offset = handle->cc - 1;
5470 for (n=0; n < handle->cc; ++n) {
5472 offset = handle->cc - 1;
5473 if (pcap_get_ring_frame_status(handle, offset) != TP_STATUS_KERNEL)
5478 * If we found free blocks, decrement the count of free
5479 * blocks by 1, just in case we lost a race with another
5480 * thread of control that was adding a packet while
5481 * we were counting and that had run the filter before
5484 * XXX - could there be more than one block added in
5487 * XXX - is there a way to avoid that race, e.g. somehow
5488 * wait for all packets that passed the old filter to
5489 * be added to the ring?
5495 * Set the count of blocks worth of packets to filter
5496 * in userland to the total number of blocks in the
5497 * ring minus the number of free blocks we found, and
5498 * turn on userland filtering. (The count of blocks
5499 * worth of packets to filter in userland is guaranteed
5500 * not to be zero - n, above, couldn't be set to a
5501 * value > handle->cc, and if it were equal to
5502 * handle->cc, it wouldn't be zero, and thus would
5503 * be decremented to handle->cc - 1.)
5505 handlep->blocks_to_filter_in_userland = handle->cc - n;
5506 handlep->filter_in_userland = 1;
5510 #endif /* HAVE_PACKET_RING */
5513 #ifdef HAVE_PF_PACKET_SOCKETS
5515 * Return the index of the given device name. Fill ebuf and return
5519 iface_get_id(int fd, const char *device, char *ebuf)
5523 memset(&ifr, 0, sizeof(ifr));
5524 strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
5526 if (ioctl(fd, SIOCGIFINDEX, &ifr) == -1) {
5527 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
5528 errno, "SIOCGIFINDEX");
5532 return ifr.ifr_ifindex;
5536 * Bind the socket associated with FD to the given device.
5537 * Return 1 on success, 0 if we should try a SOCK_PACKET socket,
5538 * or a PCAP_ERROR_ value on a hard error.
5541 iface_bind(int fd, int ifindex, char *ebuf, int protocol)
5543 struct sockaddr_ll sll;
5545 socklen_t errlen = sizeof(err);
5547 memset(&sll, 0, sizeof(sll));
5548 sll.sll_family = AF_PACKET;
5549 sll.sll_ifindex = ifindex;
5550 sll.sll_protocol = protocol;
5552 if (bind(fd, (struct sockaddr *) &sll, sizeof(sll)) == -1) {
5553 if (errno == ENETDOWN) {
5555 * Return a "network down" indication, so that
5556 * the application can report that rather than
5557 * saying we had a mysterious failure and
5558 * suggest that they report a problem to the
5559 * libpcap developers.
5561 return PCAP_ERROR_IFACE_NOT_UP;
5563 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
5569 /* Any pending errors, e.g., network is down? */
5571 if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
5572 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
5573 errno, "getsockopt");
5577 if (err == ENETDOWN) {
5579 * Return a "network down" indication, so that
5580 * the application can report that rather than
5581 * saying we had a mysterious failure and
5582 * suggest that they report a problem to the
5583 * libpcap developers.
5585 return PCAP_ERROR_IFACE_NOT_UP;
5586 } else if (err > 0) {
5587 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
5595 #ifdef IW_MODE_MONITOR
5597 * Check whether the device supports the Wireless Extensions.
5598 * Returns 1 if it does, 0 if it doesn't, PCAP_ERROR_NO_SUCH_DEVICE
5599 * if the device doesn't even exist.
5602 has_wext(int sock_fd, const char *device, char *ebuf)
5606 if (is_bonding_device(sock_fd, device))
5607 return 0; /* bonding device, so don't even try */
5609 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
5610 sizeof ireq.ifr_ifrn.ifrn_name);
5611 if (ioctl(sock_fd, SIOCGIWNAME, &ireq) >= 0)
5613 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE, errno,
5614 "%s: SIOCGIWNAME", device);
5615 if (errno == ENODEV)
5616 return PCAP_ERROR_NO_SUCH_DEVICE;
5621 * Per me si va ne la citta dolente,
5622 * Per me si va ne l'etterno dolore,
5624 * Lasciate ogne speranza, voi ch'intrate.
5626 * XXX - airmon-ng does special stuff with the Orinoco driver and the
5642 * Use the Wireless Extensions, if we have them, to try to turn monitor mode
5643 * on if it's not already on.
5645 * Returns 1 on success, 0 if we don't support the Wireless Extensions
5646 * on this device, or a PCAP_ERROR_ value if we do support them but
5647 * we weren't able to turn monitor mode on.
5650 enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device)
5653 * XXX - at least some adapters require non-Wireless Extensions
5654 * mechanisms to turn monitor mode on.
5656 * Atheros cards might require that a separate "monitor virtual access
5657 * point" be created, with later versions of the madwifi driver.
5658 * airmon-ng does "wlanconfig ath create wlandev {if} wlanmode
5659 * monitor -bssid", which apparently spits out a line "athN"
5660 * where "athN" is the monitor mode device. To leave monitor
5661 * mode, it destroys the monitor mode device.
5663 * Some Intel Centrino adapters might require private ioctls to get
5664 * radio headers; the ipw2200 and ipw3945 drivers allow you to
5665 * configure a separate "rtapN" interface to capture in monitor
5666 * mode without preventing the adapter from operating normally.
5667 * (airmon-ng doesn't appear to use that, though.)
5669 * It would be Truly Wonderful if mac80211 and nl80211 cleaned this
5670 * up, and if all drivers were converted to mac80211 drivers.
5672 * If interface {if} is a mac80211 driver, the file
5673 * /sys/class/net/{if}/phy80211 is a symlink to
5674 * /sys/class/ieee80211/{phydev}, for some {phydev}.
5676 * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at
5677 * least, has a "wmaster0" device and a "wlan0" device; the
5678 * latter is the one with the IP address. Both show up in
5679 * "tcpdump -D" output. Capturing on the wmaster0 device
5680 * captures with 802.11 headers.
5682 * airmon-ng searches through /sys/class/net for devices named
5683 * monN, starting with mon0; as soon as one *doesn't* exist,
5684 * it chooses that as the monitor device name. If the "iw"
5685 * command exists, it does "iw dev {if} interface add {monif}
5686 * type monitor", where {monif} is the monitor device. It
5687 * then (sigh) sleeps .1 second, and then configures the
5688 * device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface
5689 * is a file, it writes {mondev}, without a newline, to that file,
5690 * and again (sigh) sleeps .1 second, and then iwconfig's that
5691 * device into monitor mode and configures it up. Otherwise,
5692 * you can't do monitor mode.
5694 * All these devices are "glued" together by having the
5695 * /sys/class/net/{device}/phy80211 links pointing to the same
5696 * place, so, given a wmaster, wlan, or mon device, you can
5697 * find the other devices by looking for devices with
5698 * the same phy80211 link.
5700 * To turn monitor mode off, delete the monitor interface,
5701 * either with "iw dev {monif} interface del" or by sending
5702 * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface
5704 * Note: if you try to create a monitor device named "monN", and
5705 * there's already a "monN" device, it fails, as least with
5706 * the netlink interface (which is what iw uses), with a return
5707 * value of -ENFILE. (Return values are negative errnos.) We
5708 * could probably use that to find an unused device.
5710 struct pcap_linux *handlep = handle->priv;
5713 struct iw_priv_args *priv;
5714 monitor_type montype;
5723 * Does this device *support* the Wireless Extensions?
5725 err = has_wext(sock_fd, device, handle->errbuf);
5727 return err; /* either it doesn't or the device doesn't even exist */
5729 * Start out assuming we have no private extensions to control
5732 montype = MONITOR_WEXT;
5736 * Try to get all the Wireless Extensions private ioctls
5737 * supported by this device.
5739 * First, get the size of the buffer we need, by supplying no
5740 * buffer and a length of 0. If the device supports private
5741 * ioctls, it should return E2BIG, with ireq.u.data.length set
5742 * to the length we need. If it doesn't support them, it should
5743 * return EOPNOTSUPP.
5745 memset(&ireq, 0, sizeof ireq);
5746 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
5747 sizeof ireq.ifr_ifrn.ifrn_name);
5748 ireq.u.data.pointer = (void *)args;
5749 ireq.u.data.length = 0;
5750 ireq.u.data.flags = 0;
5751 if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) != -1) {
5752 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
5753 "%s: SIOCGIWPRIV with a zero-length buffer didn't fail!",
5757 if (errno != EOPNOTSUPP) {
5759 * OK, it's not as if there are no private ioctls.
5761 if (errno != E2BIG) {
5765 pcap_fmt_errmsg_for_errno(handle->errbuf,
5766 PCAP_ERRBUF_SIZE, errno, "%s: SIOCGIWPRIV", device);
5771 * OK, try to get the list of private ioctls.
5773 priv = malloc(ireq.u.data.length * sizeof (struct iw_priv_args));
5775 pcap_fmt_errmsg_for_errno(handle->errbuf,
5776 PCAP_ERRBUF_SIZE, errno, "malloc");
5779 ireq.u.data.pointer = (void *)priv;
5780 if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) == -1) {
5781 pcap_fmt_errmsg_for_errno(handle->errbuf,
5782 PCAP_ERRBUF_SIZE, errno, "%s: SIOCGIWPRIV", device);
5788 * Look for private ioctls to turn monitor mode on or, if
5789 * monitor mode is on, to set the header type.
5791 for (i = 0; i < ireq.u.data.length; i++) {
5792 if (strcmp(priv[i].name, "monitor_type") == 0) {
5794 * Hostap driver, use this one.
5795 * Set monitor mode first.
5796 * You can set it to 0 to get DLT_IEEE80211,
5797 * 1 to get DLT_PRISM, 2 to get
5798 * DLT_IEEE80211_RADIO_AVS, and, with more
5799 * recent versions of the driver, 3 to get
5800 * DLT_IEEE80211_RADIO.
5802 if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
5804 if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
5806 if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
5808 montype = MONITOR_HOSTAP;
5812 if (strcmp(priv[i].name, "set_prismhdr") == 0) {
5814 * Prism54 driver, use this one.
5815 * Set monitor mode first.
5816 * You can set it to 2 to get DLT_IEEE80211
5817 * or 3 or get DLT_PRISM.
5819 if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
5821 if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
5823 if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
5825 montype = MONITOR_PRISM54;
5829 if (strcmp(priv[i].name, "forceprismheader") == 0) {
5831 * RT2570 driver, use this one.
5832 * Do this after turning monitor mode on.
5833 * You can set it to 1 to get DLT_PRISM or 2
5834 * to get DLT_IEEE80211.
5836 if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
5838 if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
5840 if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
5842 montype = MONITOR_RT2570;
5846 if (strcmp(priv[i].name, "forceprism") == 0) {
5848 * RT73 driver, use this one.
5849 * Do this after turning monitor mode on.
5850 * Its argument is a *string*; you can
5851 * set it to "1" to get DLT_PRISM or "2"
5852 * to get DLT_IEEE80211.
5854 if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_CHAR)
5856 if (priv[i].set_args & IW_PRIV_SIZE_FIXED)
5858 montype = MONITOR_RT73;
5862 if (strcmp(priv[i].name, "prismhdr") == 0) {
5864 * One of the RTL8xxx drivers, use this one.
5865 * It can only be done after monitor mode
5866 * has been turned on. You can set it to 1
5867 * to get DLT_PRISM or 0 to get DLT_IEEE80211.
5869 if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
5871 if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
5873 if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
5875 montype = MONITOR_RTL8XXX;
5879 if (strcmp(priv[i].name, "rfmontx") == 0) {
5881 * RT2500 or RT61 driver, use this one.
5882 * It has one one-byte parameter; set
5883 * u.data.length to 1 and u.data.pointer to
5884 * point to the parameter.
5885 * It doesn't itself turn monitor mode on.
5886 * You can set it to 1 to allow transmitting
5887 * in monitor mode(?) and get DLT_IEEE80211,
5888 * or set it to 0 to disallow transmitting in
5889 * monitor mode(?) and get DLT_PRISM.
5891 if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
5893 if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 2)
5895 montype = MONITOR_RT2500;
5899 if (strcmp(priv[i].name, "monitor") == 0) {
5901 * Either ACX100 or hostap, use this one.
5902 * It turns monitor mode on.
5903 * If it takes two arguments, it's ACX100;
5904 * the first argument is 1 for DLT_PRISM
5905 * or 2 for DLT_IEEE80211, and the second
5906 * argument is the channel on which to
5907 * run. If it takes one argument, it's
5908 * HostAP, and the argument is 2 for
5909 * DLT_IEEE80211 and 3 for DLT_PRISM.
5911 * If we see this, we don't quit, as this
5912 * might be a version of the hostap driver
5913 * that also supports "monitor_type".
5915 if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
5917 if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
5919 switch (priv[i].set_args & IW_PRIV_SIZE_MASK) {
5922 montype = MONITOR_PRISM;
5927 montype = MONITOR_ACX100;
5940 * XXX - ipw3945? islism?
5946 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
5947 sizeof ireq.ifr_ifrn.ifrn_name);
5948 if (ioctl(sock_fd, SIOCGIWMODE, &ireq) == -1) {
5950 * We probably won't be able to set the mode, either.
5952 return PCAP_ERROR_RFMON_NOTSUP;
5956 * Is it currently in monitor mode?
5958 if (ireq.u.mode == IW_MODE_MONITOR) {
5960 * Yes. Just leave things as they are.
5961 * We don't offer multiple link-layer types, as
5962 * changing the link-layer type out from under
5963 * somebody else capturing in monitor mode would
5964 * be considered rude.
5969 * No. We have to put the adapter into rfmon mode.
5973 * If we haven't already done so, arrange to have
5974 * "pcap_close_all()" called when we exit.
5976 if (!pcap_do_addexit(handle)) {
5978 * "atexit()" failed; don't put the interface
5979 * in rfmon mode, just give up.
5981 return PCAP_ERROR_RFMON_NOTSUP;
5985 * Save the old mode.
5987 handlep->oldmode = ireq.u.mode;
5990 * Put the adapter in rfmon mode. How we do this depends
5991 * on whether we have a special private ioctl or not.
5993 if (montype == MONITOR_PRISM) {
5995 * We have the "monitor" private ioctl, but none of
5996 * the other private ioctls. Use this, and select
5999 * If it fails, just fall back on SIOCSIWMODE.
6001 memset(&ireq, 0, sizeof ireq);
6002 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
6003 sizeof ireq.ifr_ifrn.ifrn_name);
6004 ireq.u.data.length = 1; /* 1 argument */
6005 args[0] = 3; /* request Prism header */
6006 memcpy(ireq.u.name, args, sizeof (int));
6007 if (ioctl(sock_fd, cmd, &ireq) != -1) {
6010 * Note that we have to put the old mode back
6011 * when we close the device.
6013 handlep->must_do_on_close |= MUST_CLEAR_RFMON;
6016 * Add this to the list of pcaps to close
6019 pcap_add_to_pcaps_to_close(handle);
6025 * Failure. Fall back on SIOCSIWMODE.
6030 * First, take the interface down if it's up; otherwise, we
6033 memset(&ifr, 0, sizeof(ifr));
6034 strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
6035 if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) {
6036 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
6037 errno, "%s: Can't get flags", device);
6041 if (ifr.ifr_flags & IFF_UP) {
6042 oldflags = ifr.ifr_flags;
6043 ifr.ifr_flags &= ~IFF_UP;
6044 if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
6045 pcap_fmt_errmsg_for_errno(handle->errbuf,
6046 PCAP_ERRBUF_SIZE, errno, "%s: Can't set flags",
6053 * Then turn monitor mode on.
6055 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
6056 sizeof ireq.ifr_ifrn.ifrn_name);
6057 ireq.u.mode = IW_MODE_MONITOR;
6058 if (ioctl(sock_fd, SIOCSIWMODE, &ireq) == -1) {
6060 * Scientist, you've failed.
6061 * Bring the interface back up if we shut it down.
6063 ifr.ifr_flags = oldflags;
6064 if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
6065 pcap_fmt_errmsg_for_errno(handle->errbuf,
6066 PCAP_ERRBUF_SIZE, errno, "%s: Can't set flags",
6070 return PCAP_ERROR_RFMON_NOTSUP;
6074 * XXX - airmon-ng does "iwconfig {if} key off" after setting
6075 * monitor mode and setting the channel, and then does
6080 * Now select the appropriate radio header.
6086 * We don't have any private ioctl to set the header.
6090 case MONITOR_HOSTAP:
6092 * Try to select the radiotap header.
6094 memset(&ireq, 0, sizeof ireq);
6095 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
6096 sizeof ireq.ifr_ifrn.ifrn_name);
6097 args[0] = 3; /* request radiotap header */
6098 memcpy(ireq.u.name, args, sizeof (int));
6099 if (ioctl(sock_fd, cmd, &ireq) != -1)
6100 break; /* success */
6103 * That failed. Try to select the AVS header.
6105 memset(&ireq, 0, sizeof ireq);
6106 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
6107 sizeof ireq.ifr_ifrn.ifrn_name);
6108 args[0] = 2; /* request AVS header */
6109 memcpy(ireq.u.name, args, sizeof (int));
6110 if (ioctl(sock_fd, cmd, &ireq) != -1)
6111 break; /* success */
6114 * That failed. Try to select the Prism header.
6116 memset(&ireq, 0, sizeof ireq);
6117 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
6118 sizeof ireq.ifr_ifrn.ifrn_name);
6119 args[0] = 1; /* request Prism header */
6120 memcpy(ireq.u.name, args, sizeof (int));
6121 ioctl(sock_fd, cmd, &ireq);
6126 * The private ioctl failed.
6130 case MONITOR_PRISM54:
6132 * Select the Prism header.
6134 memset(&ireq, 0, sizeof ireq);
6135 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
6136 sizeof ireq.ifr_ifrn.ifrn_name);
6137 args[0] = 3; /* request Prism header */
6138 memcpy(ireq.u.name, args, sizeof (int));
6139 ioctl(sock_fd, cmd, &ireq);
6142 case MONITOR_ACX100:
6144 * Get the current channel.
6146 memset(&ireq, 0, sizeof ireq);
6147 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
6148 sizeof ireq.ifr_ifrn.ifrn_name);
6149 if (ioctl(sock_fd, SIOCGIWFREQ, &ireq) == -1) {
6150 pcap_fmt_errmsg_for_errno(handle->errbuf,
6151 PCAP_ERRBUF_SIZE, errno, "%s: SIOCGIWFREQ", device);
6154 channel = ireq.u.freq.m;
6157 * Select the Prism header, and set the channel to the
6160 memset(&ireq, 0, sizeof ireq);
6161 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
6162 sizeof ireq.ifr_ifrn.ifrn_name);
6163 args[0] = 1; /* request Prism header */
6164 args[1] = channel; /* set channel */
6165 memcpy(ireq.u.name, args, 2*sizeof (int));
6166 ioctl(sock_fd, cmd, &ireq);
6169 case MONITOR_RT2500:
6171 * Disallow transmission - that turns on the
6174 memset(&ireq, 0, sizeof ireq);
6175 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
6176 sizeof ireq.ifr_ifrn.ifrn_name);
6177 args[0] = 0; /* disallow transmitting */
6178 memcpy(ireq.u.name, args, sizeof (int));
6179 ioctl(sock_fd, cmd, &ireq);
6182 case MONITOR_RT2570:
6184 * Force the Prism header.
6186 memset(&ireq, 0, sizeof ireq);
6187 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
6188 sizeof ireq.ifr_ifrn.ifrn_name);
6189 args[0] = 1; /* request Prism header */
6190 memcpy(ireq.u.name, args, sizeof (int));
6191 ioctl(sock_fd, cmd, &ireq);
6196 * Force the Prism header.
6198 memset(&ireq, 0, sizeof ireq);
6199 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
6200 sizeof ireq.ifr_ifrn.ifrn_name);
6201 ireq.u.data.length = 1; /* 1 argument */
6202 ireq.u.data.pointer = "1";
6203 ireq.u.data.flags = 0;
6204 ioctl(sock_fd, cmd, &ireq);
6207 case MONITOR_RTL8XXX:
6209 * Force the Prism header.
6211 memset(&ireq, 0, sizeof ireq);
6212 strlcpy(ireq.ifr_ifrn.ifrn_name, device,
6213 sizeof ireq.ifr_ifrn.ifrn_name);
6214 args[0] = 1; /* request Prism header */
6215 memcpy(ireq.u.name, args, sizeof (int));
6216 ioctl(sock_fd, cmd, &ireq);
6221 * Now bring the interface back up if we brought it down.
6223 if (oldflags != 0) {
6224 ifr.ifr_flags = oldflags;
6225 if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
6226 pcap_fmt_errmsg_for_errno(handle->errbuf,
6227 PCAP_ERRBUF_SIZE, errno, "%s: Can't set flags",
6231 * At least try to restore the old mode on the
6234 if (ioctl(handle->fd, SIOCSIWMODE, &ireq) == -1) {
6236 * Scientist, you've failed.
6239 "Can't restore interface wireless mode (SIOCSIWMODE failed: %s).\n"
6240 "Please adjust manually.\n",
6248 * Note that we have to put the old mode back when we
6251 handlep->must_do_on_close |= MUST_CLEAR_RFMON;
6254 * Add this to the list of pcaps to close when we exit.
6256 pcap_add_to_pcaps_to_close(handle);
6260 #endif /* IW_MODE_MONITOR */
6263 * Try various mechanisms to enter monitor mode.
6266 enter_rfmon_mode(pcap_t *handle, int sock_fd, const char *device)
6268 #if defined(HAVE_LIBNL) || defined(IW_MODE_MONITOR)
6273 ret = enter_rfmon_mode_mac80211(handle, sock_fd, device);
6275 return ret; /* error attempting to do so */
6277 return 1; /* success */
6278 #endif /* HAVE_LIBNL */
6280 #ifdef IW_MODE_MONITOR
6281 ret = enter_rfmon_mode_wext(handle, sock_fd, device);
6283 return ret; /* error attempting to do so */
6285 return 1; /* success */
6286 #endif /* IW_MODE_MONITOR */
6289 * Either none of the mechanisms we know about work or none
6290 * of those mechanisms are available, so we can't do monitor
6296 #if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
6298 * Map SOF_TIMESTAMPING_ values to PCAP_TSTAMP_ values.
6300 static const struct {
6301 int soft_timestamping_val;
6302 int pcap_tstamp_val;
6303 } sof_ts_type_map[3] = {
6304 { SOF_TIMESTAMPING_SOFTWARE, PCAP_TSTAMP_HOST },
6305 { SOF_TIMESTAMPING_SYS_HARDWARE, PCAP_TSTAMP_ADAPTER },
6306 { SOF_TIMESTAMPING_RAW_HARDWARE, PCAP_TSTAMP_ADAPTER_UNSYNCED }
6308 #define NUM_SOF_TIMESTAMPING_TYPES (sizeof sof_ts_type_map / sizeof sof_ts_type_map[0])
6311 * Set the list of time stamping types to include all types.
6314 iface_set_all_ts_types(pcap_t *handle)
6318 handle->tstamp_type_count = NUM_SOF_TIMESTAMPING_TYPES;
6319 handle->tstamp_type_list = malloc(NUM_SOF_TIMESTAMPING_TYPES * sizeof(u_int));
6320 for (i = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++)
6321 handle->tstamp_type_list[i] = sof_ts_type_map[i].pcap_tstamp_val;
6324 #ifdef ETHTOOL_GET_TS_INFO
6326 * Get a list of time stamping capabilities.
6329 iface_ethtool_get_ts_info(const char *device, pcap_t *handle, char *ebuf)
6333 struct ethtool_ts_info info;
6338 * This doesn't apply to the "any" device; you can't say "turn on
6339 * hardware time stamping for all devices that exist now and arrange
6340 * that it be turned on for any device that appears in the future",
6341 * and not all devices even necessarily *support* hardware time
6342 * stamping, so don't report any time stamp types.
6344 if (strcmp(device, "any") == 0) {
6345 handle->tstamp_type_list = NULL;
6350 * Create a socket from which to fetch time stamping capabilities.
6352 fd = socket(PF_UNIX, SOCK_RAW, 0);
6354 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
6355 errno, "socket for SIOCETHTOOL(ETHTOOL_GET_TS_INFO)");
6359 memset(&ifr, 0, sizeof(ifr));
6360 strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
6361 memset(&info, 0, sizeof(info));
6362 info.cmd = ETHTOOL_GET_TS_INFO;
6363 ifr.ifr_data = (caddr_t)&info;
6364 if (ioctl(fd, SIOCETHTOOL, &ifr) == -1) {
6365 int save_errno = errno;
6368 switch (save_errno) {
6373 * OK, this OS version or driver doesn't support
6374 * asking for the time stamping types, so let's
6375 * just return all the possible types.
6377 iface_set_all_ts_types(handle);
6382 * OK, no such device.
6383 * The user will find that out when they try to
6384 * activate the device; just return an empty
6385 * list of time stamp types.
6387 handle->tstamp_type_list = NULL;
6394 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
6396 "%s: SIOCETHTOOL(ETHTOOL_GET_TS_INFO) ioctl failed",
6404 * Do we support hardware time stamping of *all* packets?
6406 if (!(info.rx_filters & (1 << HWTSTAMP_FILTER_ALL))) {
6408 * No, so don't report any time stamp types.
6410 * XXX - some devices either don't report
6411 * HWTSTAMP_FILTER_ALL when they do support it, or
6412 * report HWTSTAMP_FILTER_ALL but map it to only
6413 * time stamping a few PTP packets. See
6414 * http://marc.info/?l=linux-netdev&m=146318183529571&w=2
6416 handle->tstamp_type_list = NULL;
6421 for (i = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++) {
6422 if (info.so_timestamping & sof_ts_type_map[i].soft_timestamping_val)
6425 handle->tstamp_type_count = num_ts_types;
6426 if (num_ts_types != 0) {
6427 handle->tstamp_type_list = malloc(num_ts_types * sizeof(u_int));
6428 for (i = 0, j = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++) {
6429 if (info.so_timestamping & sof_ts_type_map[i].soft_timestamping_val) {
6430 handle->tstamp_type_list[j] = sof_ts_type_map[i].pcap_tstamp_val;
6435 handle->tstamp_type_list = NULL;
6439 #else /* ETHTOOL_GET_TS_INFO */
6441 iface_ethtool_get_ts_info(const char *device, pcap_t *handle, char *ebuf _U_)
6444 * This doesn't apply to the "any" device; you can't say "turn on
6445 * hardware time stamping for all devices that exist now and arrange
6446 * that it be turned on for any device that appears in the future",
6447 * and not all devices even necessarily *support* hardware time
6448 * stamping, so don't report any time stamp types.
6450 if (strcmp(device, "any") == 0) {
6451 handle->tstamp_type_list = NULL;
6456 * We don't have an ioctl to use to ask what's supported,
6457 * so say we support everything.
6459 iface_set_all_ts_types(handle);
6462 #endif /* ETHTOOL_GET_TS_INFO */
6464 #endif /* defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP) */
6466 #ifdef HAVE_PACKET_RING
6468 * Find out if we have any form of fragmentation/reassembly offloading.
6470 * We do so using SIOCETHTOOL checking for various types of offloading;
6471 * if SIOCETHTOOL isn't defined, or we don't have any #defines for any
6472 * of the types of offloading, there's nothing we can do to check, so
6473 * we just say "no, we don't".
6475 #if defined(SIOCETHTOOL) && (defined(ETHTOOL_GTSO) || defined(ETHTOOL_GUFO) || defined(ETHTOOL_GGSO) || defined(ETHTOOL_GFLAGS) || defined(ETHTOOL_GGRO))
6477 iface_ethtool_flag_ioctl(pcap_t *handle, int cmd, const char *cmdname)
6480 struct ethtool_value eval;
6482 memset(&ifr, 0, sizeof(ifr));
6483 strlcpy(ifr.ifr_name, handle->opt.device, sizeof(ifr.ifr_name));
6486 ifr.ifr_data = (caddr_t)&eval;
6487 if (ioctl(handle->fd, SIOCETHTOOL, &ifr) == -1) {
6488 if (errno == EOPNOTSUPP || errno == EINVAL) {
6490 * OK, let's just return 0, which, in our
6491 * case, either means "no, what we're asking
6492 * about is not enabled" or "all the flags
6493 * are clear (i.e., nothing is enabled)".
6497 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
6498 errno, "%s: SIOCETHTOOL(%s) ioctl failed",
6499 handle->opt.device, cmdname);
6506 iface_get_offload(pcap_t *handle)
6511 ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GTSO, "ETHTOOL_GTSO");
6515 return 1; /* TCP segmentation offloading on */
6519 ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GUFO, "ETHTOOL_GUFO");
6523 return 1; /* UDP fragmentation offloading on */
6528 * XXX - will this cause large unsegmented packets to be
6529 * handed to PF_PACKET sockets on transmission? If not,
6530 * this need not be checked.
6532 ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GGSO, "ETHTOOL_GGSO");
6536 return 1; /* generic segmentation offloading on */
6539 #ifdef ETHTOOL_GFLAGS
6540 ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GFLAGS, "ETHTOOL_GFLAGS");
6543 if (ret & ETH_FLAG_LRO)
6544 return 1; /* large receive offloading on */
6549 * XXX - will this cause large reassembled packets to be
6550 * handed to PF_PACKET sockets on receipt? If not,
6551 * this need not be checked.
6553 ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GGRO, "ETHTOOL_GGRO");
6557 return 1; /* generic (large) receive offloading on */
6562 #else /* SIOCETHTOOL */
6564 iface_get_offload(pcap_t *handle _U_)
6567 * XXX - do we need to get this information if we don't
6568 * have the ethtool ioctls? If so, how do we do that?
6572 #endif /* SIOCETHTOOL */
6574 #endif /* HAVE_PACKET_RING */
6576 #endif /* HAVE_PF_PACKET_SOCKETS */
6578 /* ===== Functions to interface to the older kernels ================== */
6581 * Try to open a packet socket using the old kernel interface.
6582 * Returns 1 on success and a PCAP_ERROR_ value on an error.
6585 activate_old(pcap_t *handle)
6587 struct pcap_linux *handlep = handle->priv;
6591 const char *device = handle->opt.device;
6592 struct utsname utsname;
6595 /* Open the socket */
6597 handle->fd = socket(PF_INET, SOCK_PACKET, htons(ETH_P_ALL));
6598 if (handle->fd == -1) {
6600 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
6602 if (err == EPERM || err == EACCES) {
6604 * You don't have permission to open the
6607 return PCAP_ERROR_PERM_DENIED;
6616 /* It worked - we are using the old interface */
6617 handlep->sock_packet = 1;
6619 /* ...which means we get the link-layer header. */
6620 handlep->cooked = 0;
6622 /* Bind to the given device */
6624 if (strcmp(device, "any") == 0) {
6625 strlcpy(handle->errbuf, "pcap_activate: The \"any\" device isn't supported on 2.0[.x]-kernel systems",
6629 if (iface_bind_old(handle->fd, device, handle->errbuf) == -1)
6633 * Try to get the link-layer type.
6635 arptype = iface_get_arptype(handle->fd, device, handle->errbuf);
6640 * Try to find the DLT_ type corresponding to that
6643 map_arphrd_to_dlt(handle, handle->fd, arptype, device, 0);
6644 if (handle->linktype == -1) {
6645 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
6646 "unknown arptype %d", arptype);
6650 /* Go to promisc mode if requested */
6652 if (handle->opt.promisc) {
6653 memset(&ifr, 0, sizeof(ifr));
6654 strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
6655 if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
6656 pcap_fmt_errmsg_for_errno(handle->errbuf,
6657 PCAP_ERRBUF_SIZE, errno, "SIOCGIFFLAGS");
6660 if ((ifr.ifr_flags & IFF_PROMISC) == 0) {
6662 * Promiscuous mode isn't currently on,
6663 * so turn it on, and remember that
6664 * we should turn it off when the
6669 * If we haven't already done so, arrange
6670 * to have "pcap_close_all()" called when
6673 if (!pcap_do_addexit(handle)) {
6675 * "atexit()" failed; don't put
6676 * the interface in promiscuous
6677 * mode, just give up.
6682 ifr.ifr_flags |= IFF_PROMISC;
6683 if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
6684 pcap_fmt_errmsg_for_errno(handle->errbuf,
6685 PCAP_ERRBUF_SIZE, errno, "SIOCSIFFLAGS");
6688 handlep->must_do_on_close |= MUST_CLEAR_PROMISC;
6691 * Add this to the list of pcaps
6692 * to close when we exit.
6694 pcap_add_to_pcaps_to_close(handle);
6699 * Compute the buffer size.
6701 * We're using SOCK_PACKET, so this might be a 2.0[.x]
6702 * kernel, and might require special handling - check.
6704 if (uname(&utsname) < 0 ||
6705 strncmp(utsname.release, "2.0", 3) == 0) {
6707 * Either we couldn't find out what kernel release
6708 * this is, or it's a 2.0[.x] kernel.
6710 * In the 2.0[.x] kernel, a "recvfrom()" on
6711 * a SOCK_PACKET socket, with MSG_TRUNC set, will
6712 * return the number of bytes read, so if we pass
6713 * a length based on the snapshot length, it'll
6714 * return the number of bytes from the packet
6715 * copied to userland, not the actual length
6718 * This means that, for example, the IP dissector
6719 * in tcpdump will get handed a packet length less
6720 * than the length in the IP header, and will
6721 * complain about "truncated-ip".
6723 * So we don't bother trying to copy from the
6724 * kernel only the bytes in which we're interested,
6725 * but instead copy them all, just as the older
6726 * versions of libpcap for Linux did.
6728 * The buffer therefore needs to be big enough to
6729 * hold the largest packet we can get from this
6730 * device. Unfortunately, we can't get the MRU
6731 * of the network; we can only get the MTU. The
6732 * MTU may be too small, in which case a packet larger
6733 * than the buffer size will be truncated *and* we
6734 * won't get the actual packet size.
6736 * However, if the snapshot length is larger than
6737 * the buffer size based on the MTU, we use the
6738 * snapshot length as the buffer size, instead;
6739 * this means that with a sufficiently large snapshot
6740 * length we won't artificially truncate packets
6741 * to the MTU-based size.
6743 * This mess just one of many problems with packet
6744 * capture on 2.0[.x] kernels; you really want a
6745 * 2.2[.x] or later kernel if you want packet capture
6748 mtu = iface_get_mtu(handle->fd, device, handle->errbuf);
6751 handle->bufsize = MAX_LINKHEADER_SIZE + mtu;
6752 if (handle->bufsize < (u_int)handle->snapshot)
6753 handle->bufsize = (u_int)handle->snapshot;
6756 * This is a 2.2[.x] or later kernel.
6758 * We can safely pass "recvfrom()" a byte count
6759 * based on the snapshot length.
6761 handle->bufsize = (u_int)handle->snapshot;
6765 * Default value for offset to align link-layer payload
6766 * on a 4-byte boundary.
6771 * SOCK_PACKET sockets don't supply information from
6772 * stripped VLAN tags.
6774 handlep->vlan_offset = -1; /* unknown */
6780 * Bind the socket associated with FD to the given device using the
6781 * interface of the old kernels.
6784 iface_bind_old(int fd, const char *device, char *ebuf)
6786 struct sockaddr saddr;
6788 socklen_t errlen = sizeof(err);
6790 memset(&saddr, 0, sizeof(saddr));
6791 strlcpy(saddr.sa_data, device, sizeof(saddr.sa_data));
6792 if (bind(fd, &saddr, sizeof(saddr)) == -1) {
6793 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
6798 /* Any pending errors, e.g., network is down? */
6800 if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
6801 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
6802 errno, "getsockopt");
6807 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
6816 /* ===== System calls available on all supported kernels ============== */
6819 * Query the kernel for the MTU of the given interface.
6822 iface_get_mtu(int fd, const char *device, char *ebuf)
6827 return BIGGER_THAN_ALL_MTUS;
6829 memset(&ifr, 0, sizeof(ifr));
6830 strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
6832 if (ioctl(fd, SIOCGIFMTU, &ifr) == -1) {
6833 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
6834 errno, "SIOCGIFMTU");
6842 * Get the hardware type of the given interface as ARPHRD_xxx constant.
6845 iface_get_arptype(int fd, const char *device, char *ebuf)
6849 memset(&ifr, 0, sizeof(ifr));
6850 strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
6852 if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) {
6853 pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
6854 errno, "SIOCGIFHWADDR");
6855 if (errno == ENODEV) {
6859 return PCAP_ERROR_NO_SUCH_DEVICE;
6864 return ifr.ifr_hwaddr.sa_family;
6867 #ifdef SO_ATTACH_FILTER
6869 fix_program(pcap_t *handle, struct sock_fprog *fcode, int is_mmapped)
6871 struct pcap_linux *handlep = handle->priv;
6874 register struct bpf_insn *p;
6879 * Make a copy of the filter, and modify that copy if
6882 prog_size = sizeof(*handle->fcode.bf_insns) * handle->fcode.bf_len;
6883 len = handle->fcode.bf_len;
6884 f = (struct bpf_insn *)malloc(prog_size);
6886 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
6890 memcpy(f, handle->fcode.bf_insns, prog_size);
6892 fcode->filter = (struct sock_filter *) f;
6894 for (i = 0; i < len; ++i) {
6897 * What type of instruction is this?
6899 switch (BPF_CLASS(p->code)) {
6903 * It's a return instruction; are we capturing
6904 * in memory-mapped mode?
6908 * No; is the snapshot length a constant,
6909 * rather than the contents of the
6912 if (BPF_MODE(p->code) == BPF_K) {
6914 * Yes - if the value to be returned,
6915 * i.e. the snapshot length, is
6916 * anything other than 0, make it
6917 * MAXIMUM_SNAPLEN, so that the packet
6918 * is truncated by "recvfrom()",
6919 * not by the filter.
6921 * XXX - there's nothing we can
6922 * easily do if it's getting the
6923 * value from the accumulator; we'd
6924 * have to insert code to force
6925 * non-zero values to be
6929 p->k = MAXIMUM_SNAPLEN;
6937 * It's a load instruction; is it loading
6940 switch (BPF_MODE(p->code)) {
6946 * Yes; are we in cooked mode?
6948 if (handlep->cooked) {
6950 * Yes, so we need to fix this
6953 if (fix_offset(p) < 0) {
6955 * We failed to do so.
6956 * Return 0, so our caller
6957 * knows to punt to userland.
6967 return 1; /* we succeeded */
6971 fix_offset(struct bpf_insn *p)
6974 * What's the offset?
6976 if (p->k >= SLL_HDR_LEN) {
6978 * It's within the link-layer payload; that starts at an
6979 * offset of 0, as far as the kernel packet filter is
6980 * concerned, so subtract the length of the link-layer
6983 p->k -= SLL_HDR_LEN;
6984 } else if (p->k == 0) {
6986 * It's the packet type field; map it to the special magic
6987 * kernel offset for that field.
6989 p->k = SKF_AD_OFF + SKF_AD_PKTTYPE;
6990 } else if (p->k == 14) {
6992 * It's the protocol field; map it to the special magic
6993 * kernel offset for that field.
6995 p->k = SKF_AD_OFF + SKF_AD_PROTOCOL;
6996 } else if ((bpf_int32)(p->k) > 0) {
6998 * It's within the header, but it's not one of those
6999 * fields; we can't do that in the kernel, so punt
7008 set_kernel_filter(pcap_t *handle, struct sock_fprog *fcode)
7010 int total_filter_on = 0;
7016 * The socket filter code doesn't discard all packets queued
7017 * up on the socket when the filter is changed; this means
7018 * that packets that don't match the new filter may show up
7019 * after the new filter is put onto the socket, if those
7020 * packets haven't yet been read.
7022 * This means, for example, that if you do a tcpdump capture
7023 * with a filter, the first few packets in the capture might
7024 * be packets that wouldn't have passed the filter.
7026 * We therefore discard all packets queued up on the socket
7027 * when setting a kernel filter. (This isn't an issue for
7028 * userland filters, as the userland filtering is done after
7029 * packets are queued up.)
7031 * To flush those packets, we put the socket in read-only mode,
7032 * and read packets from the socket until there are no more to
7035 * In order to keep that from being an infinite loop - i.e.,
7036 * to keep more packets from arriving while we're draining
7037 * the queue - we put the "total filter", which is a filter
7038 * that rejects all packets, onto the socket before draining
7041 * This code deliberately ignores any errors, so that you may
7042 * get bogus packets if an error occurs, rather than having
7043 * the filtering done in userland even if it could have been
7044 * done in the kernel.
7046 if (setsockopt(handle->fd, SOL_SOCKET, SO_ATTACH_FILTER,
7047 &total_fcode, sizeof(total_fcode)) == 0) {
7051 * Note that we've put the total filter onto the socket.
7053 total_filter_on = 1;
7056 * Save the socket's current mode, and put it in
7057 * non-blocking mode; we drain it by reading packets
7058 * until we get an error (which is normally a
7059 * "nothing more to be read" error).
7061 save_mode = fcntl(handle->fd, F_GETFL, 0);
7062 if (save_mode == -1) {
7063 pcap_fmt_errmsg_for_errno(handle->errbuf,
7064 PCAP_ERRBUF_SIZE, errno,
7065 "can't get FD flags when changing filter");
7068 if (fcntl(handle->fd, F_SETFL, save_mode | O_NONBLOCK) < 0) {
7069 pcap_fmt_errmsg_for_errno(handle->errbuf,
7070 PCAP_ERRBUF_SIZE, errno,
7071 "can't set nonblocking mode when changing filter");
7074 while (recv(handle->fd, &drain, sizeof drain, MSG_TRUNC) >= 0)
7077 if (save_errno != EAGAIN) {
7081 * If we can't restore the mode or reset the
7082 * kernel filter, there's nothing we can do.
7084 (void)fcntl(handle->fd, F_SETFL, save_mode);
7085 (void)reset_kernel_filter(handle);
7086 pcap_fmt_errmsg_for_errno(handle->errbuf,
7087 PCAP_ERRBUF_SIZE, save_errno,
7088 "recv failed when changing filter");
7091 if (fcntl(handle->fd, F_SETFL, save_mode) == -1) {
7092 pcap_fmt_errmsg_for_errno(handle->errbuf,
7093 PCAP_ERRBUF_SIZE, errno,
7094 "can't restore FD flags when changing filter");
7100 * Now attach the new filter.
7102 ret = setsockopt(handle->fd, SOL_SOCKET, SO_ATTACH_FILTER,
7103 fcode, sizeof(*fcode));
7104 if (ret == -1 && total_filter_on) {
7106 * Well, we couldn't set that filter on the socket,
7107 * but we could set the total filter on the socket.
7109 * This could, for example, mean that the filter was
7110 * too big to put into the kernel, so we'll have to
7111 * filter in userland; in any case, we'll be doing
7112 * filtering in userland, so we need to remove the
7113 * total filter so we see packets.
7118 * If this fails, we're really screwed; we have the
7119 * total filter on the socket, and it won't come off.
7120 * Report it as a fatal error.
7122 if (reset_kernel_filter(handle) == -1) {
7123 pcap_fmt_errmsg_for_errno(handle->errbuf,
7124 PCAP_ERRBUF_SIZE, errno,
7125 "can't remove kernel total filter");
7126 return -2; /* fatal error */
7135 reset_kernel_filter(pcap_t *handle)
7139 * setsockopt() barfs unless it get a dummy parameter.
7140 * valgrind whines unless the value is initialized,
7141 * as it has no idea that setsockopt() ignores its
7146 ret = setsockopt(handle->fd, SOL_SOCKET, SO_DETACH_FILTER,
7147 &dummy, sizeof(dummy));
7149 * Ignore ENOENT - it means "we don't have a filter", so there
7150 * was no filter to remove, and there's still no filter.
7152 * Also ignore ENONET, as a lot of kernel versions had a
7153 * typo where ENONET, rather than ENOENT, was returned.
7155 if (ret == -1 && errno != ENOENT && errno != ENONET)
7162 pcap_set_protocol(pcap_t *p, int protocol)
7164 if (pcap_check_activated(p))
7165 return (PCAP_ERROR_ACTIVATED);
7166 p->opt.protocol = protocol;
7171 * Libpcap version string.
7174 pcap_lib_version(void)
7176 #ifdef HAVE_PACKET_RING
7177 #if defined(HAVE_TPACKET3)
7178 return (PCAP_VERSION_STRING " (with TPACKET_V3)");
7179 #elif defined(HAVE_TPACKET2)
7180 return (PCAP_VERSION_STRING " (with TPACKET_V2)");
7182 return (PCAP_VERSION_STRING " (with TPACKET_V1)");
7185 return (PCAP_VERSION_STRING " (without TPACKET)");