libpcap  1.10.1
About: libpcap is a packet filter library used by tools like tcpdump.
  Fossies Dox: libpcap-1.10.1.tar.gz  ("unofficial" and yet experimental doxygen-generated source code documentation)  

fad-getad.c
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1 /* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
2 /*
3  * Copyright (c) 1994, 1995, 1996, 1997, 1998
4  * The Regents of the University of California. All rights reserved.
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9  * 1. Redistributions of source code must retain the above copyright
10  * notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
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13  * documentation and/or other materials provided with the distribution.
14  * 3. All advertising materials mentioning features or use of this software
15  * must display the following acknowledgement:
16  * This product includes software developed by the Computer Systems
17  * Engineering Group at Lawrence Berkeley Laboratory.
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19  * to endorse or promote products derived from this software without
20  * specific prior written permission.
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22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #ifdef HAVE_CONFIG_H
36 #include <config.h>
37 #endif
38 
39 #include <sys/types.h>
40 #include <sys/socket.h>
41 #include <netinet/in.h>
42 
43 #include <net/if.h>
44 
45 #include <errno.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <ifaddrs.h>
50 
51 #include "pcap-int.h"
52 
53 #ifdef HAVE_OS_PROTO_H
54 #include "os-proto.h"
55 #endif
56 
57 /*
58  * We don't do this on Solaris 11 and later, as it appears there aren't
59  * any AF_PACKET addresses on interfaces, so we don't need this, and
60  * we end up including both the OS's <net/bpf.h> and our <pcap/bpf.h>,
61  * and their definitions of some data structures collide.
62  */
63 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
64 # ifdef HAVE_NETPACKET_PACKET_H
65 /* Linux distributions with newer glibc */
66 # include <netpacket/packet.h>
67 # else /* HAVE_NETPACKET_PACKET_H */
68 /* LynxOS, Linux distributions with older glibc */
69 # ifdef __Lynx__
70 /* LynxOS */
71 # include <netpacket/if_packet.h>
72 # else /* __Lynx__ */
73 /* Linux */
74 # include <linux/types.h>
75 # include <linux/if_packet.h>
76 # endif /* __Lynx__ */
77 # endif /* HAVE_NETPACKET_PACKET_H */
78 #endif /* (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) */
79 
80 /*
81  * This is fun.
82  *
83  * In older BSD systems, socket addresses were fixed-length, and
84  * "sizeof (struct sockaddr)" gave the size of the structure.
85  * All addresses fit within a "struct sockaddr".
86  *
87  * In newer BSD systems, the socket address is variable-length, and
88  * there's an "sa_len" field giving the length of the structure;
89  * this allows socket addresses to be longer than 2 bytes of family
90  * and 14 bytes of data.
91  *
92  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
93  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
94  * than "struct sockaddr"), and some use the new BSD scheme.
95  *
96  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
97  * macro that determines the size based on the address family. Other
98  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
99  * but not in the final version). On the latter systems, we explicitly
100  * check the AF_ type to determine the length; we assume that on
101  * all those systems we have "struct sockaddr_storage".
102  */
103 #ifndef SA_LEN
104 #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
105 #define SA_LEN(addr) ((addr)->sa_len)
106 #else /* HAVE_STRUCT_SOCKADDR_SA_LEN */
107 #ifdef HAVE_STRUCT_SOCKADDR_STORAGE
108 static size_t
109 get_sa_len(struct sockaddr *addr)
110 {
111  switch (addr->sa_family) {
112 
113 #ifdef AF_INET
114  case AF_INET:
115  return (sizeof (struct sockaddr_in));
116 #endif
117 
118 #ifdef AF_INET6
119  case AF_INET6:
120  return (sizeof (struct sockaddr_in6));
121 #endif
122 
123 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
124  case AF_PACKET:
125  return (sizeof (struct sockaddr_ll));
126 #endif
127 
128  default:
129  return (sizeof (struct sockaddr));
130  }
131 }
132 #define SA_LEN(addr) (get_sa_len(addr))
133 #else /* HAVE_STRUCT_SOCKADDR_STORAGE */
134 #define SA_LEN(addr) (sizeof (struct sockaddr))
135 #endif /* HAVE_STRUCT_SOCKADDR_STORAGE */
136 #endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
137 #endif /* SA_LEN */
138 
139 /*
140  * Get a list of all interfaces that are up and that we can open.
141  * Returns -1 on error, 0 otherwise.
142  * The list, as returned through "alldevsp", may be null if no interfaces
143  * could be opened.
144  */
145 int
147  int (*check_usable)(const char *), get_if_flags_func get_flags_func)
148 {
149  struct ifaddrs *ifap, *ifa;
150  struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
151  size_t addr_size, broadaddr_size, dstaddr_size;
152  int ret = 0;
153  char *p, *q;
154 
155  /*
156  * Get the list of interface addresses.
157  *
158  * Note: this won't return information about interfaces
159  * with no addresses, so, if a platform has interfaces
160  * with no interfaces on which traffic can be captured,
161  * we must check for those interfaces as well (see, for
162  * example, what's done on Linux).
163  *
164  * LAN interfaces will probably have link-layer
165  * addresses; I don't know whether all implementations
166  * of "getifaddrs()" now, or in the future, will return
167  * those.
168  */
169  if (getifaddrs(&ifap) != 0) {
171  errno, "getifaddrs");
172  return (-1);
173  }
174  for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
175  /*
176  * If this entry has a colon followed by a number at
177  * the end, we assume it's a logical interface. Those
178  * are just the way you assign multiple IP addresses to
179  * a real interface on Linux, so an entry for a logical
180  * interface should be treated like the entry for the
181  * real interface; we do that by stripping off the ":"
182  * and the number.
183  *
184  * XXX - should we do this only on Linux?
185  */
186  p = strchr(ifa->ifa_name, ':');
187  if (p != NULL) {
188  /*
189  * We have a ":"; is it followed by a number?
190  */
191  q = p + 1;
192  while (PCAP_ISDIGIT(*q))
193  q++;
194  if (*q == '\0') {
195  /*
196  * All digits after the ":" until the end.
197  * Strip off the ":" and everything after
198  * it.
199  */
200  *p = '\0';
201  }
202  }
203 
204  /*
205  * Can we capture on this device?
206  */
207  if (!(*check_usable)(ifa->ifa_name)) {
208  /*
209  * No.
210  */
211  continue;
212  }
213 
214  /*
215  * "ifa_addr" was apparently null on at least one
216  * interface on some system. Therefore, we supply
217  * the address and netmask only if "ifa_addr" is
218  * non-null (if there's no address, there's obviously
219  * no netmask).
220  */
221  if (ifa->ifa_addr != NULL) {
222  addr = ifa->ifa_addr;
223  addr_size = SA_LEN(addr);
224  netmask = ifa->ifa_netmask;
225  } else {
226  addr = NULL;
227  addr_size = 0;
228  netmask = NULL;
229  }
230 
231  /*
232  * Note that, on some platforms, ifa_broadaddr and
233  * ifa_dstaddr could be the same field (true on at
234  * least some versions of *BSD and macOS), so we
235  * can't just check whether the broadcast address
236  * is null and add it if so and check whether the
237  * destination address is null and add it if so.
238  *
239  * Therefore, we must also check the IFF_BROADCAST
240  * flag, and only add a broadcast address if it's
241  * set, and check the IFF_POINTTOPOINT flag, and
242  * only add a destination address if it's set (as
243  * per man page recommendations on some of those
244  * platforms).
245  */
246  if (ifa->ifa_flags & IFF_BROADCAST &&
247  ifa->ifa_broadaddr != NULL) {
248  broadaddr = ifa->ifa_broadaddr;
249  broadaddr_size = SA_LEN(broadaddr);
250  } else {
251  broadaddr = NULL;
252  broadaddr_size = 0;
253  }
254  if (ifa->ifa_flags & IFF_POINTOPOINT &&
255  ifa->ifa_dstaddr != NULL) {
256  dstaddr = ifa->ifa_dstaddr;
257  dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
258  } else {
259  dstaddr = NULL;
260  dstaddr_size = 0;
261  }
262 
263  /*
264  * Add information for this address to the list.
265  */
266  if (add_addr_to_if(devlistp, ifa->ifa_name, ifa->ifa_flags,
267  get_flags_func,
268  addr, addr_size, netmask, addr_size,
269  broadaddr, broadaddr_size, dstaddr, dstaddr_size,
270  errbuf) < 0) {
271  ret = -1;
272  break;
273  }
274  }
275 
276  freeifaddrs(ifap);
277 
278  return (ret);
279 }
int pcap_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf, int(*check_usable)(const char *), get_if_flags_func get_flags_func)
Definition: fad-getad.c:146
#define SA_LEN(addr)
Definition: fad-getad.c:134
void pcap_fmt_errmsg_for_errno(char *errbuf, size_t errbuflen, int errnum, const char *fmt,...)
Definition: fmtutils.c:269
int errno
int add_addr_to_if(pcap_if_list_t *, const char *, bpf_u_int32, get_if_flags_func, struct sockaddr *, size_t, struct sockaddr *, size_t, struct sockaddr *, size_t, struct sockaddr *, size_t, char *)
Definition: pcap.c:1072
#define PCAP_ISDIGIT(c)
Definition: pcap-int.h:138
int(* get_if_flags_func)(const char *, bpf_u_int32 *, char *)
Definition: pcap-int.h:509
#define PCAP_ERRBUF_SIZE
Definition: pcap.h:152