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/*
* pcaputil.c
*
* Copyright (c) 2000 Dug Song <dugsong@monkey.org>
*
* $Id: pcaputil.c,v 1.2 2001/03/15 08:33:04 dugsong Exp $
*/
#include "config.h"
#include <sys/param.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <err.h>
#include <pcap.h>
#ifdef BSD
#include <pcap-int.h>
#endif
#include "pcaputil.h"
#ifdef BSD
static int
bpf_immediate(int fd, int on)
{
return (ioctl(fd, BIOCIMMEDIATE, &on));
}
#endif
int
pcap_dloff(pcap_t *pd)
{
int offset = -1;
switch (pcap_datalink(pd)) {
case DLT_EN10MB:
offset = 14;
break;
case DLT_IEEE802:
offset = 22;
break;
case DLT_FDDI:
offset = 21;
break;
#ifdef DLT_LOOP
case DLT_LOOP:
#endif
case DLT_NULL:
offset = 4;
break;
case DLT_LINUX_SLL: /* e.g. ppp */
offset = 16;
break;
default:
warnx("unsupported datalink type");
break;
}
return (offset);
}
pcap_t *
pcap_init(char *intf, char *filter, int snaplen)
{
pcap_t *pd;
u_int net, mask;
struct bpf_program fcode;
char ebuf[PCAP_ERRBUF_SIZE];
if (intf == NULL && (intf = pcap_lookupdev(ebuf)) == NULL) {
warnx("%s", ebuf);
return (NULL);
}
if ((pd = pcap_open_live(intf, snaplen, 1, 512, ebuf)) == NULL) {
warnx("%s", ebuf);
return (NULL);
}
if (pcap_lookupnet(intf, &net, &mask, ebuf) == -1) {
warnx("%s", ebuf);
return (NULL);
}
if (pcap_compile(pd, &fcode, filter, 1, mask) < 0) {
pcap_perror(pd, "pcap_compile");
return (NULL);
}
if (pcap_setfilter(pd, &fcode) == -1) {
pcap_perror(pd, "pcap_compile");
return (NULL);
}
#ifdef BSD
if (bpf_immediate(pd->fd, 1) < 0) {
perror("ioctl");
return (NULL);
}
#endif
return (pd);
}
/* from tcpdump util.c. */
char *
copy_argv(char **argv)
{
char **p, *buf, *src, *dst;
u_int len = 0;
p = argv;
if (*p == 0)
return (0);
while (*p)
len += strlen(*p++) + 1;
if ((buf = (char *)malloc(len)) == NULL)
err(1, "copy_argv: malloc");
p = argv;
dst = buf;
while ((src = *p++) != NULL) {
while ((*dst++ = *src++) != '\0')
;
dst[-1] = ' ';
}
dst[-1] = '\0';
return (buf);
}
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