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36 static const char rcsid[] _U_ =
37 "@(#) $Header: /tcpdump/master/libpcap/fad-gifc.c,v 1.12 2008-08-06 07:34:09 guy Exp $ (LBL)";
44 #include <sys/param.h>
45 #include <sys/ioctl.h>
46 #include <sys/socket.h>
47 #ifdef HAVE_SYS_SOCKIO_H
48 #include <sys/sockio.h>
50 #include <sys/time.h> /* concession to AIX */
52 struct mbuf; /* Squelch compiler warnings on some platforms for */
53 struct rtentry; /* declarations in <net/if.h> */
55 #include <netinet/in.h>
67 #ifdef HAVE_OS_PROTO_H
74 * In older BSD systems, socket addresses were fixed-length, and
75 * "sizeof (struct sockaddr)" gave the size of the structure.
76 * All addresses fit within a "struct sockaddr".
78 * In newer BSD systems, the socket address is variable-length, and
79 * there's an "sa_len" field giving the length of the structure;
80 * this allows socket addresses to be longer than 2 bytes of family
81 * and 14 bytes of data.
83 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
84 * variant of the old BSD scheme (with "struct sockaddr_storage" rather
85 * than "struct sockaddr"), and some use the new BSD scheme.
87 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
88 * macro that determines the size based on the address family. Other
89 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
90 * but not in the final version).
92 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
93 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
94 * address in an entry returned by SIOCGIFCONF.
97 #ifdef HAVE_SOCKADDR_SA_LEN
98 #define SA_LEN(addr) ((addr)->sa_len)
99 #else /* HAVE_SOCKADDR_SA_LEN */
100 #define SA_LEN(addr) (sizeof (struct sockaddr))
101 #endif /* HAVE_SOCKADDR_SA_LEN */
107 * There is no ioctl that returns the amount of space required for all
108 * the data that SIOCGIFCONF could return, and if a buffer is supplied
109 * that's not large enough for all the data SIOCGIFCONF could return,
110 * on at least some platforms it just returns the data that'd fit with
111 * no indication that there wasn't enough room for all the data, much
112 * less an indication of how much more room is required.
114 * The only way to ensure that we got all the data is to pass a buffer
115 * large enough that the amount of space in the buffer *not* filled in
116 * is greater than the largest possible entry.
118 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption
119 * that no address is more than 255 bytes (on systems where the "sa_len"
120 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the
121 * case, and addresses are unlikely to be bigger than that in any case).
123 #define MAX_SA_LEN 255
126 * Get a list of all interfaces that are up and that we can open.
127 * Returns -1 on error, 0 otherwise.
128 * The list, as returned through "alldevsp", may be null if no interfaces
129 * were up and could be opened.
131 * This is the implementation used on platforms that have SIOCGIFCONF but
132 * don't have any other mechanism for getting a list of interfaces.
134 * XXX - or platforms that have other, better mechanisms but for which
135 * we don't yet have code to use that mechanism; I think there's a better
136 * way on Linux, for example, but if that better way is "getifaddrs()",
137 * we already have that.
140 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf)
142 pcap_if_t *devlist = NULL;
144 register struct ifreq *ifrp, *ifend, *ifnext;
149 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
152 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
153 struct sockaddr *netmask, *broadaddr, *dstaddr;
154 size_t netmask_size, broadaddr_size, dstaddr_size;
158 * Create a socket from which to fetch the list of interfaces.
160 fd = socket(AF_INET, SOCK_DGRAM, 0);
162 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
163 "socket: %s", pcap_strerror(errno));
168 * Start with an 8K buffer, and keep growing the buffer until
169 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
170 * bytes left over in the buffer or we fail to get the
171 * interface list for some reason other than EINVAL (which is
172 * presumed here to mean "buffer is too small").
176 buf = malloc(buf_size);
178 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
179 "malloc: %s", pcap_strerror(errno));
184 ifc.ifc_len = buf_size;
186 memset(buf, 0, buf_size);
187 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
188 && errno != EINVAL) {
189 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
190 "SIOCGIFCONF: %s", pcap_strerror(errno));
195 if (ifc.ifc_len < buf_size &&
196 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
202 ifrp = (struct ifreq *)buf;
203 ifend = (struct ifreq *)(buf + ifc.ifc_len);
205 for (; ifrp < ifend; ifrp = ifnext) {
207 * XXX - what if this isn't an IPv4 address? Can
208 * we still get the netmask, etc. with ioctls on
211 * The answer is probably platform-dependent, and
212 * if the answer is "no" on more than one platform,
213 * the way you work around it is probably platform-
216 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
217 if (n < sizeof(*ifrp))
220 ifnext = (struct ifreq *)((char *)ifrp + n);
223 * XXX - The 32-bit compatibility layer for Linux on IA-64
224 * is slightly broken. It correctly converts the structures
225 * to and from kernel land from 64 bit to 32 bit but
226 * doesn't update ifc.ifc_len, leaving it larger than the
227 * amount really used. This means we read off the end
228 * of the buffer and encounter an interface with an
229 * "empty" name. Since this is highly unlikely to ever
230 * occur in a valid case we can just finish looking for
231 * interfaces if we see an empty name.
233 if (!(*ifrp->ifr_name))
237 * Skip entries that begin with "dummy".
238 * XXX - what are these? Is this Linux-specific?
239 * Are there platforms on which we shouldn't do this?
241 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
245 * Get the flags for this interface, and skip it if it's
248 strncpy(ifrflags.ifr_name, ifrp->ifr_name,
249 sizeof(ifrflags.ifr_name));
250 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
253 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
254 "SIOCGIFFLAGS: %.*s: %s",
255 (int)sizeof(ifrflags.ifr_name),
257 pcap_strerror(errno));
261 if (!(ifrflags.ifr_flags & IFF_UP))
265 * Get the netmask for this address on this interface.
267 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
268 sizeof(ifrnetmask.ifr_name));
269 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
270 sizeof(ifrnetmask.ifr_addr));
271 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
272 if (errno == EADDRNOTAVAIL) {
279 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
280 "SIOCGIFNETMASK: %.*s: %s",
281 (int)sizeof(ifrnetmask.ifr_name),
283 pcap_strerror(errno));
288 netmask = &ifrnetmask.ifr_addr;
289 netmask_size = SA_LEN(netmask);
293 * Get the broadcast address for this address on this
294 * interface (if any).
296 if (ifrflags.ifr_flags & IFF_BROADCAST) {
297 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
298 sizeof(ifrbroadaddr.ifr_name));
299 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
300 sizeof(ifrbroadaddr.ifr_addr));
301 if (ioctl(fd, SIOCGIFBRDADDR,
302 (char *)&ifrbroadaddr) < 0) {
303 if (errno == EADDRNOTAVAIL) {
310 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
311 "SIOCGIFBRDADDR: %.*s: %s",
312 (int)sizeof(ifrbroadaddr.ifr_name),
313 ifrbroadaddr.ifr_name,
314 pcap_strerror(errno));
319 broadaddr = &ifrbroadaddr.ifr_broadaddr;
320 broadaddr_size = SA_LEN(broadaddr);
324 * Not a broadcast interface, so no broadcast
332 * Get the destination address for this address on this
333 * interface (if any).
335 if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
336 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
337 sizeof(ifrdstaddr.ifr_name));
338 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
339 sizeof(ifrdstaddr.ifr_addr));
340 if (ioctl(fd, SIOCGIFDSTADDR,
341 (char *)&ifrdstaddr) < 0) {
342 if (errno == EADDRNOTAVAIL) {
349 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
350 "SIOCGIFDSTADDR: %.*s: %s",
351 (int)sizeof(ifrdstaddr.ifr_name),
353 pcap_strerror(errno));
358 dstaddr = &ifrdstaddr.ifr_dstaddr;
359 dstaddr_size = SA_LEN(dstaddr);
363 * Not a point-to-point interface, so no destination
370 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
372 * If this entry has a colon followed by a number at
373 * the end, it's a logical interface. Those are just
374 * the way you assign multiple IP addresses to a real
375 * interface, so an entry for a logical interface should
376 * be treated like the entry for the real interface;
377 * we do that by stripping off the ":" and the number.
379 p = strchr(ifrp->ifr_name, ':');
382 * We have a ":"; is it followed by a number?
385 while (isdigit((unsigned char)*q))
389 * All digits after the ":" until the end.
390 * Strip off the ":" and everything after
399 * Add information for this address to the list.
401 if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
402 ifrflags.ifr_flags, &ifrp->ifr_addr,
403 SA_LEN(&ifrp->ifr_addr), netmask, netmask_size,
404 broadaddr, broadaddr_size, dstaddr, dstaddr_size,
415 * We had an error; free the list we've been constructing.
417 if (devlist != NULL) {
418 pcap_freealldevs(devlist);