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/*
* $Id: linux.c,v 1.5 2009/02/03 12:51:50 c4chris Exp $
*
* Christian Iseli
* Ludwig Institute for Cancer Research
* UNIL - BEP
* CH-1015 Lausanne
* Switzerland
*
*/
#include "os.h"
#ifdef USE_LINUX
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netpacket/packet.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <netinet/in.h>
#include <errno.h>
#include "nfswatch.h"
#include "externs.h"
static void
linux_get_def_dev(char **device)
{
int n, s;
struct ifreq *ifrp;
struct ifconf ifc;
char buf[BUFSIZ];
/*
* Grab a socket.
*/
if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
error("socket");
finish(-1);
}
ifc.ifc_buf = buf;
ifc.ifc_len = sizeof(buf);
/*
* See what devices we've got.
*/
if (ioctl(s, SIOCGIFCONF, (char *) &ifc) < 0) {
error("ioctl: SIOCGIFCONF");
finish(-1);
}
/*
* Take the first device we encounter.
*/
ifrp = ifc.ifc_req;
for (n = ifc.ifc_len/sizeof(struct ifreq); n > 0; n--,ifrp++) {
/*
* Skip the loopback interface.
*/
if (strcmp(ifrp->ifr_name, "lo") == 0)
continue;
*device = strdup(ifrp->ifr_name);
break;
}
(void) close(s);
}
/*
* setup_linux_dev - set up the network interface tap.
*/
int
setup_linux_dev(char **device, linux_socket_handle_p_t ls)
{
char errbuf[PCAP_ERRBUF_SIZE];
/*
* If the interface device was not specified,
* get the default one.
*/
if (device != NULL && *device == NULL) {
linux_get_def_dev(device);
if (*device == NULL) {
error("linux: couldn't determine default device");
finish(-1);
}
}
errbuf[0] = 0;
if (device == NULL) {
ls->pcap = pcap_open_live(NULL, 65536, 0, 10, errbuf);
ls->device = "any";
} else {
ls->pcap = pcap_open_live(*device, 65536, 1, 10, errbuf);
ls->device = *device;
}
if (ls->pcap == NULL) {
fprintf(stderr, "Failed to open device: %s\n", errbuf);
finish(-1);
}
if (errbuf[0] != 0)
fprintf(stderr, "Warning: %s\n", errbuf);
ls->s = pcap_get_selectable_fd(ls->pcap);
if (ls->s == -1) {
fprintf(stderr, "Failed to get a selectable file descriptor\n");
finish(-1);
}
/* Determine link type. */
ls->linktype = pcap_datalink(ls->pcap);
ls->offset = 2;
/* Grab a big enough buffer. */
ls->bufsize = 65536;
ls->buffer = (u_char *)malloc(ls->bufsize + ls->offset);
if (ls->buffer == NULL) {
perror("malloc");
finish(-1);
}
return(ls->s);
}
int
linux_read_packet(linux_socket_handle_p_t ls)
{
u_char *bp;
int res;
struct pcap_pkthdr *hdr;
const u_char *data;
/* Receive a single packet from the kernel */
bp = ls->buffer + ls->offset;
res = pcap_next_ex(ls->pcap, &hdr, &data);
if (res == -1) {
pcap_perror(ls->pcap, "Error reading packet: ");
return -1;
}
if (res <= 0)
return 0;
memcpy(bp, data, hdr->caplen);
ls->len = hdr->caplen;
ls->ts = hdr->ts;
ls->bp = bp;
return 1;
}
#endif /* USE_LINUX */
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