On Fri, Apr 16, 2004 at 12:17:54AM +0200, Jacky Buyck wrote:
> This last one, if I've correctly understand handle all the addresses
> that can be use on an interface.
Yes, but note that they aren't all necessarily IPv4 addresses - you have
to check the "sa_family" member of the address before printing it as an
IPv4 address.
I've attached a sample program (based on the test program written by the
person who first implemented "pcap_findalldevs()") that lists all
interfaces - try that program.
#include "pcap.h"
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include "config.h"
void ifprint(pcap_if_t *d);
char *iptos(u_long in);
int main()
{
pcap_if_t *alldevs;
pcap_if_t *d;
char *s;
bpf_u_int32 net, mask;
char errbuf[PCAP_ERRBUF_SIZE+1];
if (pcap_findalldevs(&alldevs, errbuf) == -1)
{
fprintf(stderr,"Error in pcap_findalldevs: %s\n",errbuf);
exit(1);
}
for(d=alldevs;d;d=d->next)
{
ifprint(d);
}
if ( (s = pcap_lookupdev(errbuf)) == NULL)
{
fprintf(stderr,"Error in pcap_lookupdev: %s\n",errbuf);
}
else
{
printf("Preferred device name: %s\n",s);
}
if (pcap_lookupnet(s, &net, &mask, errbuf) < 0)
{
fprintf(stderr,"Error in pcap_lookupnet: %s\n",errbuf);
}
else
{
printf("Preferred device is on network: %s/%s\n",iptos(net), iptos(mask));
}
exit(0);
}
void ifprint(pcap_if_t *d)
{
pcap_addr_t *a;
#ifdef INET6
char ntop_buf[INET6_ADDRSTRLEN];
#endif
printf("%s\n",d->name);
if (d->description)
printf("\tDescription: %s\n",d->description);
printf("\tLoopback: %s\n",(d->flags & PCAP_IF_LOOPBACK)?"yes":"no");
for(a=d->addresses;a;a=a->next) {
switch(a->addr->sa_family)
{
case AF_INET:
printf("\tAddress Family: AF_INET\n");
if (a->addr)
printf("\t\tAddress: %s\n",
inet_ntoa(((struct sockaddr_in *)(a->addr))->sin_addr));
if (a->netmask)
printf("\t\tNetmask: %s\n",
inet_ntoa(((struct sockaddr_in *)(a->netmask))->sin_addr));
if (a->broadaddr)
printf("\t\tBroadcast Address: %s\n",
inet_ntoa(((struct sockaddr_in *)(a->broadaddr))->sin_addr));
if (a->dstaddr)
printf("\t\tDestination Address: %s\n",
inet_ntoa(((struct sockaddr_in *)(a->dstaddr))->sin_addr));
break;
#ifdef INET6
case AF_INET6:
printf("\tAddress Family: AF_INET6\n");
if (a->addr)
printf("\t\tAddress: %s\n",
inet_ntop(AF_INET6,
((struct sockaddr_in6 *)(a->addr))->sin6_addr.s6_addr,
ntop_buf, sizeof ntop_buf));
if (a->netmask)
printf("\t\tNetmask: %s\n",
inet_ntop(AF_INET6,
((struct sockaddr_in6 *)(a->netmask))->sin6_addr.s6_addr,
ntop_buf, sizeof ntop_buf));
if (a->broadaddr)
printf("\t\tBroadcast Address: %s\n",
inet_ntop(AF_INET6,
((struct sockaddr_in6 *)(a->broadaddr))->sin6_addr.s6_addr,
ntop_buf, sizeof ntop_buf));
if (a->dstaddr)
printf("\t\tDestination Address: %s\n",
inet_ntop(AF_INET6,
((struct sockaddr_in6 *)(a->dstaddr))->sin6_addr.s6_addr,
ntop_buf, sizeof ntop_buf));
break;
#endif
default:
printf("\tAddress Family: Unknown (%d)\n", a->addr->sa_family);
break;
}
}
printf("\n");
}
/* From tcptraceroute */
#define IPTOSBUFFERS 12
char *iptos(u_long in)
{
static char output[IPTOSBUFFERS][3*4+3+1];
static short which;
u_char *p;
p = (u_char *)∈
which = (which + 1 == IPTOSBUFFERS ? 0 : which + 1);
sprintf(output[which], "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
return output[which];
}
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