/* * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that: (1) source code distributions * retain the above copyright notice and this paragraph in its entirety, (2) * distributions including binary code include the above copyright notice and * this paragraph in its entirety in the documentation or other materials * provided with the distribution, and (3) all advertising materials mentioning * features or use of this software display the following acknowledgement: * ``This product includes software developed by the University of California, * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of * the University nor the names of its contributors may be used to endorse * or promote products derived from this software without specific prior * written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. * * Modifications made to accommodate the new SunOS4.0 NIT facility by * Micky Liu, micky@cunixc.cc.columbia.edu, Columbia University in May, 1989. * This module now handles the STREAMS based NIT. */ #ifndef lint static const char rcsid[] _U_ = "@(#) $Header: /tcpdump/master/libpcap/pcap-snit.c,v 1.72.2.1 2005/05/03 18:54:38 guy Exp $ (LBL)"; #endif #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "pcap-int.h" #ifdef HAVE_OS_PROTO_H #include "os-proto.h" #endif /* * The chunk size for NIT. This is the amount of buffering * done for read calls. */ #define CHUNKSIZE (2*1024) /* * The total buffer space used by NIT. */ #define BUFSPACE (4*CHUNKSIZE) /* Forwards */ static int nit_setflags(int, int, int, char *); static int pcap_stats_snit(pcap_t *p, struct pcap_stat *ps) { /* * "ps_recv" counts packets handed to the filter, not packets * that passed the filter. As filtering is done in userland, * this does not include packets dropped because we ran out * of buffer space. * * "ps_drop" counts packets dropped inside the "/dev/nit" * device because of flow control requirements or resource * exhaustion; it doesn't count packets dropped by the * interface driver, or packets dropped upstream. As filtering * is done in userland, it counts packets regardless of whether * they would've passed the filter. * * These statistics don't include packets not yet read from the * kernel by libpcap or packets not yet read from libpcap by the * application. */ *ps = p->md.stat; return (0); } static int pcap_read_snit(pcap_t *p, int cnt, pcap_handler callback, u_char *user) { register int cc, n; register struct bpf_insn *fcode = p->fcode.bf_insns; register u_char *bp, *cp, *ep; register struct nit_bufhdr *hdrp; register struct nit_iftime *ntp; register struct nit_iflen *nlp; register struct nit_ifdrops *ndp; register int caplen; cc = p->cc; if (cc == 0) { cc = read(p->fd, (char *)p->buffer, p->bufsize); if (cc < 0) { if (errno == EWOULDBLOCK) return (0); snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s", pcap_strerror(errno)); return (-1); } bp = p->buffer; } else bp = p->bp; /* * loop through each snapshot in the chunk */ n = 0; ep = bp + cc; while (bp < ep) { /* * Has "pcap_breakloop()" been called? * If so, return immediately - if we haven't read any * packets, clear the flag and return -2 to indicate * that we were told to break out of the loop, otherwise * leave the flag set, so that the *next* call will break * out of the loop without having read any packets, and * return the number of packets we've processed so far. */ if (p->break_loop) { if (n == 0) { p->break_loop = 0; return (-2); } else { p->bp = bp; p->cc = ep - bp; return (n); } } ++p->md.stat.ps_recv; cp = bp; /* get past NIT buffer */ hdrp = (struct nit_bufhdr *)cp; cp += sizeof(*hdrp); /* get past NIT timer */ ntp = (struct nit_iftime *)cp; cp += sizeof(*ntp); ndp = (struct nit_ifdrops *)cp; p->md.stat.ps_drop = ndp->nh_drops; cp += sizeof *ndp; /* get past packet len */ nlp = (struct nit_iflen *)cp; cp += sizeof(*nlp); /* next snapshot */ bp += hdrp->nhb_totlen; caplen = nlp->nh_pktlen; if (caplen > p->snapshot) caplen = p->snapshot; if (bpf_filter(fcode, cp, nlp->nh_pktlen, caplen)) { struct pcap_pkthdr h; h.ts = ntp->nh_timestamp; h.len = nlp->nh_pktlen; h.caplen = caplen; (*callback)(user, &h, cp); if (++n >= cnt && cnt >= 0) { p->cc = ep - bp; p->bp = bp; return (n); } } } p->cc = 0; return (n); } static int pcap_inject_snit(pcap_t *p, const void *buf, size_t size) { struct strbuf ctl, data; /* * XXX - can we just do * ret = write(pd->f, buf, size); */ ctl.len = sizeof(*sa); /* XXX - what was this? */ ctl.buf = (char *)sa; data.buf = buf; data.len = size; ret = putmsg(p->fd, &ctl, &data); if (ret == -1) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s", pcap_strerror(errno)); return (-1); } return (ret); } static int nit_setflags(int fd, int promisc, int to_ms, char *ebuf) { bpf_u_int32 flags; struct strioctl si; struct timeval timeout; si.ic_timout = INFTIM; if (to_ms != 0) { timeout.tv_sec = to_ms / 1000; timeout.tv_usec = (to_ms * 1000) % 1000000; si.ic_cmd = NIOCSTIME; si.ic_len = sizeof(timeout); si.ic_dp = (char *)&timeout; if (ioctl(fd, I_STR, (char *)&si) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSTIME: %s", pcap_strerror(errno)); return (-1); } } flags = NI_TIMESTAMP | NI_LEN | NI_DROPS; if (promisc) flags |= NI_PROMISC; si.ic_cmd = NIOCSFLAGS; si.ic_len = sizeof(flags); si.ic_dp = (char *)&flags; if (ioctl(fd, I_STR, (char *)&si) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSFLAGS: %s", pcap_strerror(errno)); return (-1); } return (0); } pcap_t * pcap_open_live(const char *device, int snaplen, int promisc, int to_ms, char *ebuf) { struct strioctl si; /* struct for ioctl() */ struct ifreq ifr; /* interface request struct */ int chunksize = CHUNKSIZE; int fd; static char dev[] = "/dev/nit"; register pcap_t *p; p = (pcap_t *)malloc(sizeof(*p)); if (p == NULL) { strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE); return (NULL); } if (snaplen < 96) /* * NIT requires a snapshot length of at least 96. */ snaplen = 96; memset(p, 0, sizeof(*p)); /* * Initially try a read/write open (to allow the inject * method to work). If that fails due to permission * issues, fall back to read-only. This allows a * non-root user to be granted specific access to pcap * capabilities via file permissions. * * XXX - we should have an API that has a flag that * controls whether to open read-only or read-write, * so that denial of permission to send (or inability * to send, if sending packets isn't supported on * the device in question) can be indicated at open * time. */ p->fd = fd = open(dev, O_RDWR); if (fd < 0 && errno == EACCES) p->fd = fd = open(dev, O_RDONLY); if (fd < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "%s: %s", dev, pcap_strerror(errno)); goto bad; } /* arrange to get discrete messages from the STREAM and use NIT_BUF */ if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "I_SRDOPT: %s", pcap_strerror(errno)); goto bad; } if (ioctl(fd, I_PUSH, "nbuf") < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "push nbuf: %s", pcap_strerror(errno)); goto bad; } /* set the chunksize */ si.ic_cmd = NIOCSCHUNK; si.ic_timout = INFTIM; si.ic_len = sizeof(chunksize); si.ic_dp = (char *)&chunksize; if (ioctl(fd, I_STR, (char *)&si) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSCHUNK: %s", pcap_strerror(errno)); goto bad; } /* request the interface */ strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0'; si.ic_cmd = NIOCBIND; si.ic_len = sizeof(ifr); si.ic_dp = (char *)𝔦 if (ioctl(fd, I_STR, (char *)&si) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCBIND: %s: %s", ifr.ifr_name, pcap_strerror(errno)); goto bad; } /* set the snapshot length */ si.ic_cmd = NIOCSSNAP; si.ic_len = sizeof(snaplen); si.ic_dp = (char *)&snaplen; if (ioctl(fd, I_STR, (char *)&si) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSSNAP: %s", pcap_strerror(errno)); goto bad; } p->snapshot = snaplen; if (nit_setflags(p->fd, promisc, to_ms, ebuf) < 0) goto bad; (void)ioctl(fd, I_FLUSH, (char *)FLUSHR); /* * NIT supports only ethernets. */ p->linktype = DLT_EN10MB; p->bufsize = BUFSPACE; p->buffer = (u_char *)malloc(p->bufsize); if (p->buffer == NULL) { strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE); goto bad; } /* * "p->fd" is an FD for a STREAMS device, so "select()" and * "poll()" should work on it. */ p->selectable_fd = p->fd; /* * This is (presumably) a real Ethernet capture; give it a * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so * that an application can let you choose it, in case you're * capturing DOCSIS traffic that a Cisco Cable Modem * Termination System is putting out onto an Ethernet (it * doesn't put an Ethernet header onto the wire, it puts raw * DOCSIS frames out on the wire inside the low-level * Ethernet framing). */ p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2); /* * If that fails, just leave the list empty. */ if (p->dlt_list != NULL) { p->dlt_list[0] = DLT_EN10MB; p->dlt_list[1] = DLT_DOCSIS; p->dlt_count = 2; } p->read_op = pcap_read_snit; p->inject_op = pcap_inject_snit; p->setfilter_op = install_bpf_program; /* no kernel filtering */ p->setdirection_op = NULL; /* Not implemented. */ p->set_datalink_op = NULL; /* can't change data link type */ p->getnonblock_op = pcap_getnonblock_fd; p->setnonblock_op = pcap_setnonblock_fd; p->stats_op = pcap_stats_snit; p->close_op = pcap_close_common; return (p); bad: if (fd >= 0) close(fd); free(p); return (NULL); } int pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf) { return (0); }