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AIX Version 4.3 Communications Programming Concepts
Receiving Packets Over Ethernet Example Program
#include <stdio.h>
#include <sys/ndd_var.h>
#include <sys/kinfo.h>
/*
* Get the MAC address of the ethernet adapter we're using...
*/
getaddr(char *device, char *addr)
{
int size;
struct kinfo_ndd *nddp;
void *end;
int found = 0;
size = getkerninfo(KINFO_NDD, 0, 0, 0);
if (size == 0) {
fprintf(stderr, "No ndds.\n");
exit(0);
}
if (size < 0) {
perror("getkerninfo 1");
exit(1);
}
nddp = (struct kinfo_ndd *)malloc(size);
if (!nddp) {
perror("malloc");
exit(1);
}
if (getkerninfo(KINFO_NDD, nddp, &size, 0) < 0) {
perror("getkerninfo 2");
exit(2);
}
end = (void *)nddp + size;
while (((void *)nddp < end) && !found) {
if (!strcmp(nddp->ndd_alias, device) ||
!strcmp(nddp->ndd_name, device)) {
found++;
bcopy(nddp->ndd_addr, addr, 6);
} else
nddp++;
}
return (found);
}
/*
* Hex print function...
*/
pit(str, buf, len)
u_char *str;
u_char *buf;
int len;
{
int i;
printf("%s", str);
for (i=0; i<len; i++)
printf("%2.2X", buf[i]);
printf("\n");
fflush(stdout);
}
/*
* Ethernet packet format...
*/
typedef struct {
unsigned char dst[6];
unsigned char src[6];
unsigned short ethertype;
unsigned char data[1500];
} xmit;
main(int argc, char *argv[]) {
char *device;
u_int ethertype;
xmit buf;
int s;
struct sockaddr_ndd_8022 sa;
int cc;
if (argc != 3) {
printf("Usage: %s <ifname> ethertype\n", argv[0]);
printf("EG: %s ent0 0x600\n", argv[0]);
exit(1);
}
device = argv[1];
sscanf(argv[2], "%x", ðertype);
printf("Ethertype: %x\n", ethertype);
s = socket(AF_NDD, SOCK_DGRAM, NDD_PROT_ETHER);
if (s < 0) {
perror("socket");
exit(1);
}
sa.sndd_8022_family = AF_NDD;
sa.sndd_8022_len = sizeof(sa);
sa.sndd_8022_filtertype = NS_ETHERTYPE;
sa.sndd_8022_ethertype = (u_short)ethertype;
sa.sndd_8022_filterlen = sizeof(struct ns_8022);
bcopy(device, sa.sndd_8022_nddname, sizeof(sa.sndd_8022_nddname));
if (bind(s, (struct sockaddr *)&sa, sizeof(sa))) {
perror("bind");
exit(2);
}
if (connect(s, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
perror("connect");
exit(3);
}
do {
if ((cc = read(s, &buf, sizeof(buf))) < 0) {
perror("write");
exit(4);
}
if (cc) {
printf("Read %d bytes:\n", cc);
pit("\tsrc = ", buf.src, 6);
pit("\tdst = ", buf.dst, 6);
pit("\ttype = ", &(buf.ethertype), 2);
printf("\tdata string: %s\n", buf.data);
}
} while (cc > 0);
close(s);
}
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