On Dec 10, 2011, at 11:58 PM, Cedric Cellier wrote:
>> I got it to work.
> (...)
>>> default: /* We got traffic */
>>> pcap_dispatch(pcap0,-1, (void *) packet_callback, NULL);
>>> pcap_dispatch(pcap1,-1, (void *) packet_callback2, NULL);
>
> So that other may benefit from it in the future, I
> guess your fixed version looks like:
>
> default:
> if (t==pcap0) pcap_dispatch(pcap0,...)
> else if (t==pcap1) pcap_dispatch(pcap1,...)
I would not guess that, because select() returns a count of the number of
descriptors that are ready to read - it does not return one of the descriptors
that are ready to read - and because pcap0 and pcap1 are pointers to pcap_t
structures, not descriptors.
The right way to do this is
pcap0 = pcap_open_live(device0, BUFSIZ, 1, -1, errbuf);
if (pcap0 == NULL)
/* report failure */
pcap1 = pcap_open_live(device1, BUFSIZ, 1, -1, errbuf);
if (pcap1 == NULL)
/* report failure */
/*
* If this is being built with a version of libpcap that doesn't
* include pcap_get_selectable_fd(), use pcap_fileno(), but be
* prepared to be surprised if the devices don't happen to be
* selectable or if you're running on Windows.
*/
pcapfd0 = pcap_get_selectable_fd(pcap0);
if (pcapfd0 == -1)
/* fail with an indication that you can't select on device0 */
pcapfd1 = pcap_get_selectable_fd(pcap1);
if (pcapfd1 == -1)
/* fail with an indication that you can't select on device1 */
for(;;)
{
/* If you include STDIN_FILENO, be sure to read from it when you get
traffic from it, or select will return every time it is called,
since there will still be traffic waiting there.
*/
FD_ZERO(&fd_wait);
//FD_SET(STDIN_FILENO, &fd_wait);
FD_SET(pcapfd0, &fd_wait);
FD_SET(pcapfd1, &fd_wait);
st.tv_sec = 1;
st.tv_usec = 0; /* 1000 = 1 second */
t=select(FD_SETSIZE, &fd_wait, NULL, NULL, &st);
printf("t is %d\n",t);
switch(t)
{
case -1: /* Something went really wrong */
printf("select failed: %s\n", strerror(errno));
exit(1);
case 0: /* We timed out, no trafffic */
printf( " Time out ! \n");
break;
default: /* We got traffic */
//if (FD_ISSET(STDIN_FILENO, &fd_wait))
// process information from the standard input
if (FD_ISSET(pcapfd0, &fd_wait))
{
if (pcap_dispatch(pcap0,-1, (void *) packet_callback, NULL) == -1)
/* report an error processing packets from device0 */
}
if (FD_ISSET(pcapfd1, &fd_wait))
{
if (pcap_dispatch(pcap1,-1, (void *) packet_callback2, NULL) == -1)
/* report an error processing packets from device0 */
}
}
}
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