pcaputil.c

/*
 * 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 <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;
	default:
		warnx("unsupported datalink type");
		break;
	}
	return (offset);
}

pcap_t *
pcap_init_internal(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);
}