1 #ifdef HAVE_CONFIG_H
2 #include "config.h"
3 #endif
4 
5 #include <stdlib.h>
6 #include <sys/types.h>
7 #include <sys/socket.h>
8 #include <netinet/in.h>
9 #include <arpa/inet.h>
10 #include <netdb.h>
11 
12 #include <pcap.h>
13 
14 static void ifprint(pcap_if_t *d);
15 static char *iptos(bpf_u_int32 in);
16 
main(int argc,char ** argv)17 int main(int argc, char **argv)
18 {
19   pcap_if_t *alldevs;
20   pcap_if_t *d;
21   char *s;
22   bpf_u_int32 net, mask;
23 
24   char errbuf[PCAP_ERRBUF_SIZE+1];
25   if (pcap_findalldevs(&alldevs, errbuf) == -1)
26   {
27     fprintf(stderr,"Error in pcap_findalldevs: %s\n",errbuf);
28     exit(1);
29   }
30   for(d=alldevs;d;d=d->next)
31   {
32     ifprint(d);
33   }
34 
35   if ( (s = pcap_lookupdev(errbuf)) == NULL)
36   {
37     fprintf(stderr,"Error in pcap_lookupdev: %s\n",errbuf);
38   }
39   else
40   {
41     printf("Preferred device name: %s\n",s);
42   }
43 
44   if (pcap_lookupnet(s, &net, &mask, errbuf) < 0)
45   {
46     fprintf(stderr,"Error in pcap_lookupnet: %s\n",errbuf);
47   }
48   else
49   {
50     printf("Preferred device is on network: %s/%s\n",iptos(net), iptos(mask));
51   }
52 
53   exit(0);
54 }
55 
ifprint(pcap_if_t * d)56 static void ifprint(pcap_if_t *d)
57 {
58   pcap_addr_t *a;
59 #ifdef INET6
60   char ntop_buf[INET6_ADDRSTRLEN];
61 #endif
62 
63   printf("%s\n",d->name);
64   if (d->description)
65     printf("\tDescription: %s\n",d->description);
66   printf("\tLoopback: %s\n",(d->flags & PCAP_IF_LOOPBACK)?"yes":"no");
67 
68   for(a=d->addresses;a;a=a->next) {
69     switch(a->addr->sa_family)
70     {
71       case AF_INET:
72         printf("\tAddress Family: AF_INET\n");
73         if (a->addr)
74           printf("\t\tAddress: %s\n",
75             inet_ntoa(((struct sockaddr_in *)(a->addr))->sin_addr));
76         if (a->netmask)
77           printf("\t\tNetmask: %s\n",
78             inet_ntoa(((struct sockaddr_in *)(a->netmask))->sin_addr));
79         if (a->broadaddr)
80           printf("\t\tBroadcast Address: %s\n",
81             inet_ntoa(((struct sockaddr_in *)(a->broadaddr))->sin_addr));
82         if (a->dstaddr)
83           printf("\t\tDestination Address: %s\n",
84             inet_ntoa(((struct sockaddr_in *)(a->dstaddr))->sin_addr));
85         break;
86 #ifdef INET6
87       case AF_INET6:
88         printf("\tAddress Family: AF_INET6\n");
89         if (a->addr)
90           printf("\t\tAddress: %s\n",
91             inet_ntop(AF_INET6,
92                ((struct sockaddr_in6 *)(a->addr))->sin6_addr.s6_addr,
93                ntop_buf, sizeof ntop_buf));
94         if (a->netmask)
95           printf("\t\tNetmask: %s\n",
96             inet_ntop(AF_INET6,
97               ((struct sockaddr_in6 *)(a->netmask))->sin6_addr.s6_addr,
98                ntop_buf, sizeof ntop_buf));
99         if (a->broadaddr)
100           printf("\t\tBroadcast Address: %s\n",
101             inet_ntop(AF_INET6,
102               ((struct sockaddr_in6 *)(a->broadaddr))->sin6_addr.s6_addr,
103                ntop_buf, sizeof ntop_buf));
104         if (a->dstaddr)
105           printf("\t\tDestination Address: %s\n",
106             inet_ntop(AF_INET6,
107               ((struct sockaddr_in6 *)(a->dstaddr))->sin6_addr.s6_addr,
108                ntop_buf, sizeof ntop_buf));
109         break;
110 #endif
111       default:
112         printf("\tAddress Family: Unknown (%d)\n", a->addr->sa_family);
113         break;
114     }
115   }
116   printf("\n");
117 }
118 
119 /* From tcptraceroute */
120 #define IPTOSBUFFERS	12
iptos(bpf_u_int32 in)121 static char *iptos(bpf_u_int32 in)
122 {
123 	static char output[IPTOSBUFFERS][3*4+3+1];
124 	static short which;
125 	u_char *p;
126 
127 	p = (u_char *)&in;
128 	which = (which + 1 == IPTOSBUFFERS ? 0 : which + 1);
129 	sprintf(output[which], "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
130 	return output[which];
131 }
132