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39 #include <sys/param.h>
40 #include <sys/ioctl.h>
41 #include <sys/socket.h>
42 #ifdef HAVE_SYS_SOCKIO_H
43 #include <sys/sockio.h>
45 #include <sys/time.h> /* concession to AIX */
47 struct mbuf; /* Squelch compiler warnings on some platforms for */
48 struct rtentry; /* declarations in <net/if.h> */
50 #include <netinet/in.h>
63 #define INT_MAX 2147483647
68 #ifdef HAVE_OS_PROTO_H
75 * In older BSD systems, socket addresses were fixed-length, and
76 * "sizeof (struct sockaddr)" gave the size of the structure.
77 * All addresses fit within a "struct sockaddr".
79 * In newer BSD systems, the socket address is variable-length, and
80 * there's an "sa_len" field giving the length of the structure;
81 * this allows socket addresses to be longer than 2 bytes of family
82 * and 14 bytes of data.
84 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
85 * variant of the old BSD scheme (with "struct sockaddr_storage" rather
86 * than "struct sockaddr"), and some use the new BSD scheme.
88 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
89 * macro that determines the size based on the address family. Other
90 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
91 * but not in the final version).
93 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
94 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
95 * address in an entry returned by SIOCGIFCONF.
98 #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
99 #define SA_LEN(addr) ((addr)->sa_len)
100 #else /* HAVE_STRUCT_SOCKADDR_SA_LEN */
101 #define SA_LEN(addr) (sizeof (struct sockaddr))
102 #endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
108 * There is no ioctl that returns the amount of space required for all
109 * the data that SIOCGIFCONF could return, and if a buffer is supplied
110 * that's not large enough for all the data SIOCGIFCONF could return,
111 * on at least some platforms it just returns the data that'd fit with
112 * no indication that there wasn't enough room for all the data, much
113 * less an indication of how much more room is required.
115 * The only way to ensure that we got all the data is to pass a buffer
116 * large enough that the amount of space in the buffer *not* filled in
117 * is greater than the largest possible entry.
119 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption
120 * that no address is more than 255 bytes (on systems where the "sa_len"
121 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the
122 * case, and addresses are unlikely to be bigger than that in any case).
124 #define MAX_SA_LEN 255
127 * Get a list of all interfaces that are up and that we can open.
128 * Returns -1 on error, 0 otherwise.
129 * The list, as returned through "alldevsp", may be null if no interfaces
130 * were up and could be opened.
132 * This is the implementation used on platforms that have SIOCGIFCONF but
133 * don't have any other mechanism for getting a list of interfaces.
135 * XXX - or platforms that have other, better mechanisms but for which
136 * we don't yet have code to use that mechanism; I think there's a better
137 * way on Linux, for example, but if that better way is "getifaddrs()",
138 * we already have that.
141 pcap_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf,
142 int (*check_usable)(const char *), get_if_flags_func get_flags_func)
145 register struct ifreq *ifrp, *ifend, *ifnext;
150 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
153 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
154 struct sockaddr *netmask, *broadaddr, *dstaddr;
155 size_t netmask_size, broadaddr_size, dstaddr_size;
159 * Create a socket from which to fetch the list of interfaces.
161 fd = socket(AF_INET, SOCK_DGRAM, 0);
163 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
169 * Start with an 8K buffer, and keep growing the buffer until
170 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
171 * bytes left over in the buffer or we fail to get the
172 * interface list for some reason other than EINVAL (which is
173 * presumed here to mean "buffer is too small").
178 * Don't let the buffer size get bigger than INT_MAX.
180 if (buf_size > INT_MAX) {
181 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
182 "interface information requires more than %u bytes",
187 buf = malloc(buf_size);
189 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
195 ifc.ifc_len = buf_size;
197 memset(buf, 0, buf_size);
198 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
199 && errno != EINVAL) {
200 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
201 errno, "SIOCGIFCONF");
206 if (ifc.ifc_len < (int)buf_size &&
207 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
213 ifrp = (struct ifreq *)buf;
214 ifend = (struct ifreq *)(buf + ifc.ifc_len);
216 for (; ifrp < ifend; ifrp = ifnext) {
218 * XXX - what if this isn't an IPv4 address? Can
219 * we still get the netmask, etc. with ioctls on
222 * The answer is probably platform-dependent, and
223 * if the answer is "no" on more than one platform,
224 * the way you work around it is probably platform-
227 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
228 if (n < sizeof(*ifrp))
231 ifnext = (struct ifreq *)((char *)ifrp + n);
234 * XXX - The 32-bit compatibility layer for Linux on IA-64
235 * is slightly broken. It correctly converts the structures
236 * to and from kernel land from 64 bit to 32 bit but
237 * doesn't update ifc.ifc_len, leaving it larger than the
238 * amount really used. This means we read off the end
239 * of the buffer and encounter an interface with an
240 * "empty" name. Since this is highly unlikely to ever
241 * occur in a valid case we can just finish looking for
242 * interfaces if we see an empty name.
244 if (!(*ifrp->ifr_name))
248 * Skip entries that begin with "dummy".
249 * XXX - what are these? Is this Linux-specific?
250 * Are there platforms on which we shouldn't do this?
252 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
256 * Can we capture on this device?
258 if (!(*check_usable)(ifrp->ifr_name)) {
266 * Get the flags for this interface.
268 strncpy(ifrflags.ifr_name, ifrp->ifr_name,
269 sizeof(ifrflags.ifr_name));
270 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
273 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
274 errno, "SIOCGIFFLAGS: %.*s",
275 (int)sizeof(ifrflags.ifr_name),
282 * Get the netmask for this address on this interface.
284 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
285 sizeof(ifrnetmask.ifr_name));
286 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
287 sizeof(ifrnetmask.ifr_addr));
288 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
289 if (errno == EADDRNOTAVAIL) {
296 pcap_fmt_errmsg_for_errno(errbuf,
297 PCAP_ERRBUF_SIZE, errno,
298 "SIOCGIFNETMASK: %.*s",
299 (int)sizeof(ifrnetmask.ifr_name),
300 ifrnetmask.ifr_name);
305 netmask = &ifrnetmask.ifr_addr;
306 netmask_size = SA_LEN(netmask);
310 * Get the broadcast address for this address on this
311 * interface (if any).
313 if (ifrflags.ifr_flags & IFF_BROADCAST) {
314 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
315 sizeof(ifrbroadaddr.ifr_name));
316 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
317 sizeof(ifrbroadaddr.ifr_addr));
318 if (ioctl(fd, SIOCGIFBRDADDR,
319 (char *)&ifrbroadaddr) < 0) {
320 if (errno == EADDRNOTAVAIL) {
327 pcap_fmt_errmsg_for_errno(errbuf,
328 PCAP_ERRBUF_SIZE, errno,
329 "SIOCGIFBRDADDR: %.*s",
330 (int)sizeof(ifrbroadaddr.ifr_name),
331 ifrbroadaddr.ifr_name);
336 broadaddr = &ifrbroadaddr.ifr_broadaddr;
337 broadaddr_size = SA_LEN(broadaddr);
341 * Not a broadcast interface, so no broadcast
349 * Get the destination address for this address on this
350 * interface (if any).
352 if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
353 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
354 sizeof(ifrdstaddr.ifr_name));
355 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
356 sizeof(ifrdstaddr.ifr_addr));
357 if (ioctl(fd, SIOCGIFDSTADDR,
358 (char *)&ifrdstaddr) < 0) {
359 if (errno == EADDRNOTAVAIL) {
366 pcap_fmt_errmsg_for_errno(errbuf,
367 PCAP_ERRBUF_SIZE, errno,
368 "SIOCGIFDSTADDR: %.*s",
369 (int)sizeof(ifrdstaddr.ifr_name),
370 ifrdstaddr.ifr_name);
375 dstaddr = &ifrdstaddr.ifr_dstaddr;
376 dstaddr_size = SA_LEN(dstaddr);
380 * Not a point-to-point interface, so no destination
387 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
389 * If this entry has a colon followed by a number at
390 * the end, it's a logical interface. Those are just
391 * the way you assign multiple IP addresses to a real
392 * interface, so an entry for a logical interface should
393 * be treated like the entry for the real interface;
394 * we do that by stripping off the ":" and the number.
396 p = strchr(ifrp->ifr_name, ':');
399 * We have a ":"; is it followed by a number?
402 while (isdigit((unsigned char)*q))
406 * All digits after the ":" until the end.
407 * Strip off the ":" and everything after
416 * Add information for this address to the list.
418 if (add_addr_to_if(devlistp, ifrp->ifr_name,
419 ifrflags.ifr_flags, get_flags_func,
420 &ifrp->ifr_addr, SA_LEN(&ifrp->ifr_addr),
421 netmask, netmask_size, broadaddr, broadaddr_size,
422 dstaddr, dstaddr_size, errbuf) < 0) {