I used the FD_IFSET() way to fnd out the descriptor.
I have an issue,
For few time dispatch works fine, but after I write the stats to a file,
and the loop returns to phy0, the programs quits with switch condition of
-1.
I don't see why ? I have the pcap{0,1} to non blocking. But this does not
work after sometime and I have an error displayed
: Interrupted system call
Abhinav
On Sun, Dec 11, 2011 at 3:21 AM, Guy Harris <[email protected]> wrote:
>
> 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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>
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