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Use "pcap_get_selectable_fd()" if we have it, and if it returns -1, 

don't do a "select()".

svn path=/trunk/; revision=14358
This commit is contained in:
Guy Harris 2005-05-12 03:31:33 +00:00
parent 33db7e6fcb
commit d5bad28951
2 changed files with 53 additions and 32 deletions
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1
acinclude.m4
View File

@ -469,6 +469,7 @@ and did you also install that package?]]))
[Define to 1 if you have the `pcap_findalldevs' function and a pcap.h that declares pcap_if_t.])
AC_CHECK_FUNCS(pcap_datalink_val_to_name pcap_datalink_name_to_val)
AC_CHECK_FUNCS(pcap_list_datalinks pcap_set_datalink pcap_lib_version)
AC_CHECK_FUNCS(pcap_get_selectable_fd)
fi
LIBS="$ac_save_LIBS"
])

84
capture_loop.c
View File

@ -671,7 +671,13 @@ static int capture_loop_open_input(capture_options *capture_opts, loop_data *ld,
}
#ifdef MUST_DO_SELECT
if (!ld->from_cap_pipe) ld->pcap_fd = pcap_fileno(ld->pcap_h);
if (!ld->from_cap_pipe) {
#ifdef HAVE_PCAP_GET_SELECTABLE_FD
ld->pcap_fd = pcap_get_selectable_fd(ld->pcap_h);
#else
ld->pcap_fd = pcap_fileno(ld->pcap_h);
#endif
}
#endif
/* Does "open_err_str" contain a non-empty string? If so, "pcap_open_live()"
@ -864,8 +870,8 @@ capture_loop_dispatch(capture_options *capture_opts, loop_data *ld,
#endif
#ifndef _WIN32
/* dispatch from capture pipe */
if (ld->from_cap_pipe) {
/* dispatch from capture pipe */
FD_ZERO(&set1);
FD_SET(ld->cap_pipe_fd, &set1);
timeout.tv_sec = 0;
@ -893,7 +899,7 @@ capture_loop_dispatch(capture_options *capture_opts, loop_data *ld,
else
#endif /* _WIN32 */
{
/* dispatch from pcap using select */
/* dispatch from pcap */
#ifdef MUST_DO_SELECT
/*
* Sigh. The semantics of the read timeout argument to
@ -921,39 +927,53 @@ capture_loop_dispatch(capture_options *capture_opts, loop_data *ld,
* at least on some versions of some flavors of BSD, the timer
* doesn't start until a read is done, so it won't expire if
* only a "select()" or "poll()" is posted.
*
* If we have "pcap_get_selectable_fd()", we use it to get the
* descriptor on which to select; if that's -1, it means there
* is no descriptor on which you can do a "select()" (perhaps
* because you're capturing on a special device, and that device's
* driver unfortunately doesn't support "select()", in which case
* we don't do the select - which means Ethereal might block,
* unable to accept user input, until a packet arrives. If
* that's unacceptable, plead with whoever supplies the software
* for that device to add "select()" support.
*/
FD_ZERO(&set1);
FD_SET(ld->pcap_fd, &set1);
timeout.tv_sec = 0;
timeout.tv_usec = CAP_READ_TIMEOUT*1000;
sel_ret = select(ld->pcap_fd+1, &set1, NULL, NULL, &timeout);
if (sel_ret > 0) {
/*
* "select()" says we can read from it without blocking; go for
* it.
*/
inpkts = pcap_dispatch(ld->pcap_h, 1, capture_loop_packet_cb, (gchar *)ld);
if (inpkts < 0) {
ld->pcap_err = TRUE;
ld->go = FALSE;
}
} else {
inpkts = 0;
if (sel_ret < 0 && errno != EINTR) {
g_snprintf(errmsg, errmsg_len,
"Unexpected error from select: %s", strerror(errno));
capture_loop_popup_errmsg(capture_opts, errmsg);
if (ld->pcap_fd != -1) {
FD_ZERO(&set1);
FD_SET(ld->pcap_fd, &set1);
timeout.tv_sec = 0;
timeout.tv_usec = CAP_READ_TIMEOUT*1000;
sel_ret = select(ld->pcap_fd+1, &set1, NULL, NULL, &timeout);
if (sel_ret > 0) {
/*
* "select()" says we can read from it without blocking; go for
* it.
*/
inpkts = pcap_dispatch(ld->pcap_h, 1, capture_loop_packet_cb, (gchar *)ld);
if (inpkts < 0) {
ld->pcap_err = TRUE;
ld->go = FALSE;
}
} else {
inpkts = 0;
if (sel_ret < 0 && errno != EINTR) {
g_snprintf(errmsg, errmsg_len,
"Unexpected error from select: %s", strerror(errno));
capture_loop_popup_errmsg(capture_opts, errmsg);
ld->go = FALSE;
}
}
}
else
#endif /* MUST_DO_SELECT */
{
/* dispatch from pcap without select */
inpkts = pcap_dispatch(ld->pcap_h, 1, capture_loop_packet_cb, (gchar *) ld);
if (inpkts < 0) {
ld->pcap_err = TRUE;
ld->go = FALSE;
}
}
#else
/* dispatch from pcap without select */
inpkts = pcap_dispatch(ld->pcap_h, 1, capture_loop_packet_cb, (gchar *) ld);
if (inpkts < 0) {
ld->pcap_err = TRUE;
ld->go = FALSE;
}
#endif /* MUST_DO_SELECT */
}
return inpkts;