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/* ARP packet tracing routines
* Copyright 1991 Phil Karn, KA9Q
*/
#include <stdio.h>
#include "listen.h"
#define ARP_REQUEST 1
#define ARP_REPLY 2
#define REVARP_REQUEST 3
#define REVARP_REPLY 4
#define ARP_AX25 3
#define AXALEN 7
#define PID_IP 0xCC
void arp_dump(unsigned char *data, int length)
{
int is_ip = 0;
int hardware;
int protocol;
int hwlen;
int pralen;
int operation;
unsigned char *shwaddr, *sprotaddr;
unsigned char *thwaddr, *tprotaddr;
char tmp[25];
lprintf(T_PROTOCOL, "ARP: ");
lprintf(T_IPHDR, "len %d", length);
if (length < 16) {
lprintf(T_ERROR, " bad packet\n");
return;
}
hardware = get16(data + 0);
protocol = get16(data + 2);
hwlen = data[4];
pralen = data[5];
operation = get16(data + 6);
if (hardware != ARP_AX25) {
lprintf(T_IPHDR, " non-AX25 ARP packet\n");
return;
}
lprintf(T_IPHDR, " hwtype AX25");
/* Print hardware length only if it doesn't match
* the length in the known types table
*/
if (hwlen != AXALEN)
lprintf(T_IPHDR, " hwlen %d", hwlen);
if (protocol == PID_IP) {
lprintf(T_IPHDR, " prot IP");
is_ip = 1;
} else {
lprintf(T_IPHDR, " prot 0x%x prlen %d", protocol, pralen);
}
switch (operation) {
case ARP_REQUEST:
lprintf(T_IPHDR, " op REQUEST");
break;
case ARP_REPLY:
lprintf(T_IPHDR, " op REPLY");
break;
case REVARP_REQUEST:
lprintf(T_IPHDR, " op REVERSE REQUEST");
break;
case REVARP_REPLY:
lprintf(T_IPHDR, " op REVERSE REPLY");
break;
default:
lprintf(T_IPHDR, " op %d", operation);
break;
}
shwaddr = data + 8;
sprotaddr = shwaddr + hwlen;
thwaddr = sprotaddr + pralen;
tprotaddr = thwaddr + hwlen;
lprintf(T_IPHDR, "\nsender");
if (is_ip)
lprintf(T_ADDR, " IPaddr %d.%d.%d.%d",
sprotaddr[0], sprotaddr[1],
sprotaddr[2], sprotaddr[3]);
lprintf(T_IPHDR, " hwaddr %s\n", pax25(tmp, shwaddr));
lprintf(T_IPHDR, "target");
if (is_ip)
lprintf(T_ADDR, " IPaddr %d.%d.%d.%d",
tprotaddr[0], tprotaddr[1],
tprotaddr[2], tprotaddr[3]);
if (*thwaddr != 0)
lprintf(T_ADDR, " hwaddr %s", pax25(tmp, thwaddr));
lprintf(T_IPHDR, "\n");
}
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