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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>
62 #ifdef HAVE_OS_PROTO_H
69 * In older BSD systems, socket addresses were fixed-length, and
70 * "sizeof (struct sockaddr)" gave the size of the structure.
71 * All addresses fit within a "struct sockaddr".
73 * In newer BSD systems, the socket address is variable-length, and
74 * there's an "sa_len" field giving the length of the structure;
75 * this allows socket addresses to be longer than 2 bytes of family
76 * and 14 bytes of data.
78 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
79 * variant of the old BSD scheme (with "struct sockaddr_storage" rather
80 * than "struct sockaddr"), and some use the new BSD scheme.
82 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
83 * macro that determines the size based on the address family. Other
84 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
85 * but not in the final version).
87 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
88 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
89 * address in an entry returned by SIOCGIFCONF.
92 #ifdef HAVE_SOCKADDR_SA_LEN
93 #define SA_LEN(addr) ((addr)->sa_len)
94 #else /* HAVE_SOCKADDR_SA_LEN */
95 #define SA_LEN(addr) (sizeof (struct sockaddr))
96 #endif /* HAVE_SOCKADDR_SA_LEN */
102 * There is no ioctl that returns the amount of space required for all
103 * the data that SIOCGIFCONF could return, and if a buffer is supplied
104 * that's not large enough for all the data SIOCGIFCONF could return,
105 * on at least some platforms it just returns the data that'd fit with
106 * no indication that there wasn't enough room for all the data, much
107 * less an indication of how much more room is required.
109 * The only way to ensure that we got all the data is to pass a buffer
110 * large enough that the amount of space in the buffer *not* filled in
111 * is greater than the largest possible entry.
113 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption
114 * that no address is more than 255 bytes (on systems where the "sa_len"
115 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the
116 * case, and addresses are unlikely to be bigger than that in any case).
118 #define MAX_SA_LEN 255
121 * Get a list of all interfaces that are up and that we can open.
122 * Returns -1 on error, 0 otherwise.
123 * The list, as returned through "alldevsp", may be null if no interfaces
124 * were up and could be opened.
126 * This is the implementation used on platforms that have SIOCGIFCONF but
127 * don't have any other mechanism for getting a list of interfaces.
129 * XXX - or platforms that have other, better mechanisms but for which
130 * we don't yet have code to use that mechanism; I think there's a better
131 * way on Linux, for example, but if that better way is "getifaddrs()",
132 * we already have that.
135 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf,
136 int (*check_usable)(const char *))
138 pcap_if_t *devlist = NULL;
140 register struct ifreq *ifrp, *ifend, *ifnext;
145 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
148 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
149 struct sockaddr *netmask, *broadaddr, *dstaddr;
150 size_t netmask_size, broadaddr_size, dstaddr_size;
154 * Create a socket from which to fetch the list of interfaces.
156 fd = socket(AF_INET, SOCK_DGRAM, 0);
158 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
159 "socket: %s", pcap_strerror(errno));
164 * Start with an 8K buffer, and keep growing the buffer until
165 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
166 * bytes left over in the buffer or we fail to get the
167 * interface list for some reason other than EINVAL (which is
168 * presumed here to mean "buffer is too small").
172 buf = malloc(buf_size);
174 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
175 "malloc: %s", pcap_strerror(errno));
180 ifc.ifc_len = buf_size;
182 memset(buf, 0, buf_size);
183 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
184 && errno != EINVAL) {
185 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
186 "SIOCGIFCONF: %s", pcap_strerror(errno));
191 if (ifc.ifc_len < buf_size &&
192 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
198 ifrp = (struct ifreq *)buf;
199 ifend = (struct ifreq *)(buf + ifc.ifc_len);
201 for (; ifrp < ifend; ifrp = ifnext) {
203 * XXX - what if this isn't an IPv4 address? Can
204 * we still get the netmask, etc. with ioctls on
207 * The answer is probably platform-dependent, and
208 * if the answer is "no" on more than one platform,
209 * the way you work around it is probably platform-
212 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
213 if (n < sizeof(*ifrp))
216 ifnext = (struct ifreq *)((char *)ifrp + n);
219 * XXX - The 32-bit compatibility layer for Linux on IA-64
220 * is slightly broken. It correctly converts the structures
221 * to and from kernel land from 64 bit to 32 bit but
222 * doesn't update ifc.ifc_len, leaving it larger than the
223 * amount really used. This means we read off the end
224 * of the buffer and encounter an interface with an
225 * "empty" name. Since this is highly unlikely to ever
226 * occur in a valid case we can just finish looking for
227 * interfaces if we see an empty name.
229 if (!(*ifrp->ifr_name))
233 * Skip entries that begin with "dummy".
234 * XXX - what are these? Is this Linux-specific?
235 * Are there platforms on which we shouldn't do this?
237 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
241 * Can we capture on this device?
243 if (!(*check_usable)(ifrp->ifr_name)) {
251 * Get the flags for this interface.
253 strncpy(ifrflags.ifr_name, ifrp->ifr_name,
254 sizeof(ifrflags.ifr_name));
255 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
258 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
259 "SIOCGIFFLAGS: %.*s: %s",
260 (int)sizeof(ifrflags.ifr_name),
262 pcap_strerror(errno));
268 * Get the netmask for this address on this interface.
270 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
271 sizeof(ifrnetmask.ifr_name));
272 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
273 sizeof(ifrnetmask.ifr_addr));
274 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
275 if (errno == EADDRNOTAVAIL) {
282 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
283 "SIOCGIFNETMASK: %.*s: %s",
284 (int)sizeof(ifrnetmask.ifr_name),
286 pcap_strerror(errno));
291 netmask = &ifrnetmask.ifr_addr;
292 netmask_size = SA_LEN(netmask);
296 * Get the broadcast address for this address on this
297 * interface (if any).
299 if (ifrflags.ifr_flags & IFF_BROADCAST) {
300 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
301 sizeof(ifrbroadaddr.ifr_name));
302 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
303 sizeof(ifrbroadaddr.ifr_addr));
304 if (ioctl(fd, SIOCGIFBRDADDR,
305 (char *)&ifrbroadaddr) < 0) {
306 if (errno == EADDRNOTAVAIL) {
313 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
314 "SIOCGIFBRDADDR: %.*s: %s",
315 (int)sizeof(ifrbroadaddr.ifr_name),
316 ifrbroadaddr.ifr_name,
317 pcap_strerror(errno));
322 broadaddr = &ifrbroadaddr.ifr_broadaddr;
323 broadaddr_size = SA_LEN(broadaddr);
327 * Not a broadcast interface, so no broadcast
335 * Get the destination address for this address on this
336 * interface (if any).
338 if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
339 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
340 sizeof(ifrdstaddr.ifr_name));
341 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
342 sizeof(ifrdstaddr.ifr_addr));
343 if (ioctl(fd, SIOCGIFDSTADDR,
344 (char *)&ifrdstaddr) < 0) {
345 if (errno == EADDRNOTAVAIL) {
352 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
353 "SIOCGIFDSTADDR: %.*s: %s",
354 (int)sizeof(ifrdstaddr.ifr_name),
356 pcap_strerror(errno));
361 dstaddr = &ifrdstaddr.ifr_dstaddr;
362 dstaddr_size = SA_LEN(dstaddr);
366 * Not a point-to-point interface, so no destination
373 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
375 * If this entry has a colon followed by a number at
376 * the end, it's a logical interface. Those are just
377 * the way you assign multiple IP addresses to a real
378 * interface, so an entry for a logical interface should
379 * be treated like the entry for the real interface;
380 * we do that by stripping off the ":" and the number.
382 p = strchr(ifrp->ifr_name, ':');
385 * We have a ":"; is it followed by a number?
388 while (isdigit((unsigned char)*q))
392 * All digits after the ":" until the end.
393 * Strip off the ":" and everything after
402 * Add information for this address to the list.
404 if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
405 if_flags_to_pcap_flags(ifrp->ifr_name, ifrflags.ifr_flags),
406 &ifrp->ifr_addr, SA_LEN(&ifrp->ifr_addr),
407 netmask, netmask_size, broadaddr, broadaddr_size,
408 dstaddr, dstaddr_size, errbuf) < 0) {
418 * We had an error; free the list we've been constructing.
420 if (devlist != NULL) {
421 pcap_freealldevs(devlist);