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AIX Version 4.3 Communications Programming Concepts
Analyzing Packets Over the Network Example Program
/*
* Simple sniffer to capture 802.2 frames on 802.3 ethernet, token ring,
* FDDI, and other CDLI devices that support 802.2 encapsulation...
*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/ndd_var.h>
#include <sys/tok_demux.h>
#include <netinet/if_802_5.h>
main(argc, argv)
int argc;
char *argv[];
{
int s;
struct sockaddr_ndd_8022 sa;
struct sockaddr_ndd_8022 from;
struct sockaddr *fromp = (struct sockaddr *)&from;
int len;
char buf[2000];
int cc;
u_long fromlen;
int sap;
struct ie5_mac_hdr *macp = (struct ie5_mac_hdr *)buf;
struct ie2_llc_hdr *llcp;
if (argc != 3) {
printf("Usage %s <interface> <sap>\n", argv[0]);
exit(1);
}
sscanf(argv[2], "%x", &sap);
printf("sap is %x\n", sap);
s = socket(AF_NDD, SOCK_DGRAM, 0);
if (s < 0) {
perror("socket");
exit(1);
}
sa.sndd_8022_family = AF_NDD;
sa.sndd_8022_len = sizeof(struct sockaddr_ndd_8022);
sa.sndd_8022_filtertype = NS_TAP;
sa.sndd_8022_filterlen = sizeof(ns_8022_t);
strcpy(sa.sndd_8022_nddname, argv[1]);
if (bind(s, (struct sockaddr *)&sa, sizeof(struct sockaddr_ndd_8022))) {
perror("bind");
exit(2);
}
len = sizeof(buf);
fromlen = sizeof(from);
while (TRUE) {
if ((cc = recvfrom(s, buf, len, 0, fromp, &fromlen)) < 0) {
perror("recvfrom");
exit(3);
}
if (!strcmp(argv[1], "ent0"))
llcp = (struct ie2_llc_hdr *)(buf+14);
else
llcp = (struct ie2_llc_hdr *)(buf + mac_size(macp));
if ((llcp->dsap == sap) || (llcp->ssap == sap))
printit(buf, cc);
}
}
printit(char *buf, int cc)
{
int i;
printf("FRAME: ");
for (i=0; i < cc; i++)
printf("%2.2x", *(buf+i));
printf("\n");
}
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