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When activating a device, return PCAP_ERROR_IFACE_NOT_UP if the device 

isn't up, so applications can report that differently from a generic
error (the latter could mean there's a bug somewhere in libpcap).

When capturing on a device without mmap on Linux, ignore ENETDOWN, so
that we can continue to capture traffic if the interface goes down and
comes back up again; comments in the kernel indicate that we'll just
block waiting for packets if we try to receive from a socket that
delivered ENETDOWN, and, if we're using a memory-mapped buffer, we won't
even get notified of "network down" events.
This commit is contained in:
guy 2008-07-01 08:02:33 +00:00
parent a8e63c60ed
commit 34624f128f
5 changed files with 87 additions and 25 deletions
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33
pcap-bpf.c
View File

@ -20,7 +20,7 @@
*/
#ifndef lint
static const char rcsid[] _U_ =
"@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.110 2008-04-14 20:40:58 guy Exp $ (LBL)";
"@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.111 2008-07-01 08:02:33 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
@ -413,11 +413,23 @@ pcap_can_set_rfmon_bpf(pcap_t *p)
*/
(void)strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name));
if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"BIOCSETIF: %s: %s",
p->opt.source, pcap_strerror(errno));
close(fd);
return (PCAP_ERROR);
if (errno == ENETDOWN) {
/*
* Return a "network down" indication, so that
* the application can report that rather than
* saying we had a mysterious failure and
* suggest that they report a problem to the
* libpcap developers.
*/
close(fd);
return (PCAP_ERROR_IFACE_NOT_UP);
} else {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"BIOCSETIF: %s: %s",
p->opt.source, pcap_strerror(errno));
close(fd);
return (PCAP_ERROR);
}
}
/*
@ -1016,6 +1028,15 @@ check_setif_failure(pcap_t *p, int error)
*/
strcpy(p->errbuf, "");
return (PCAP_ERROR_NO_SUCH_DEVICE);
} else if (errno == ENETDOWN) {
/*
* Return a "network down" indication, so that
* the application can report that rather than
* saying we had a mysterious failure and
* suggest that they report a problem to the
* libpcap developers.
*/
return (PCAP_ERROR_IFACE_NOT_UP);
} else {
/*
* Some other error; fill in the error string, and

63
pcap-linux.c
View File

@ -34,7 +34,7 @@
#ifndef lint
static const char rcsid[] _U_ =
"@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.149 2008-06-24 06:44:32 guy Exp $ (LBL)";
"@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.150 2008-07-01 08:02:33 guy Exp $ (LBL)";
#endif
/*
@ -646,8 +646,21 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata)
offset = 0;
#endif
/* Receive a single packet from the kernel */
/*
* Receive a single packet from the kernel.
* We ignore EINTR, as that might just be due to a signal
* being delivered - if the signal should interrupt the
* loop, the signal handler should call pcap_breakloop()
* to set handle->break_loop (we ignore it on other
* platforms as well).
* We also ignore ENETDOWN, so that we can continue to
* capture traffic if the interface goes down and comes
* back up again; comments in the kernel indicate that
* we'll just block waiting for packets if we try to
* receive from a socket that delivered ENETDOWN, and,
* if we're using a memory-mapped buffer, we won't even
* get notified of "network down" events.
*/
bp = handle->buffer + handle->offset;
do {
/*
@ -667,7 +680,7 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata)
handle->fd, bp + offset,
handle->bufsize - offset, MSG_TRUNC,
(struct sockaddr *) &from, &fromlen);
} while (packet_len == -1 && errno == EINTR);
} while (packet_len == -1 && (errno == EINTR || errno == ENETDOWN));
/* Check if an error occured */
@ -1722,10 +1735,10 @@ activate_new(pcap_t *handle)
}
if ((err = iface_bind(sock_fd, handle->md.ifindex,
handle->errbuf)) < 0) {
handle->errbuf)) != 1) {
close(sock_fd);
if (err == -2)
return PCAP_ERROR;
if (err < 0)
return err;
else
return 0; /* try old mechanism */
}
@ -2183,6 +2196,8 @@ iface_get_id(int fd, const char *device, char *ebuf)
/*
* Bind the socket associated with FD to the given device.
* Return 1 on success, 0 if we should try a SOCK_PACKET socket,
* or a PCAP_ERROR_ value on a hard error.
*/
static int
iface_bind(int fd, int ifindex, char *ebuf)
@ -2197,9 +2212,20 @@ iface_bind(int fd, int ifindex, char *ebuf)
sll.sll_protocol = htons(ETH_P_ALL);
if (bind(fd, (struct sockaddr *) &sll, sizeof(sll)) == -1) {
snprintf(ebuf, PCAP_ERRBUF_SIZE,
"bind: %s", pcap_strerror(errno));
return -1;
if (errno == ENETDOWN) {
/*
* Return a "network down" indication, so that
* the application can report that rather than
* saying we had a mysterious failure and
* suggest that they report a problem to the
* libpcap developers.
*/
return PCAP_ERROR_IFACE_NOT_UP;
} else {
snprintf(ebuf, PCAP_ERRBUF_SIZE,
"bind: %s", pcap_strerror(errno));
return PCAP_ERROR;
}
}
/* Any pending errors, e.g., network is down? */
@ -2207,16 +2233,25 @@ iface_bind(int fd, int ifindex, char *ebuf)
if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
snprintf(ebuf, PCAP_ERRBUF_SIZE,
"getsockopt: %s", pcap_strerror(errno));
return -2;
return 0;
}
if (err > 0) {
if (err == ENETDOWN) {
/*
* Return a "network down" indication, so that
* the application can report that rather than
* saying we had a mysterious failure and
* suggest that they report a problem to the
* libpcap developers.
*/
return PCAP_ERROR_IFACE_NOT_UP;
} else if (err > 0) {
snprintf(ebuf, PCAP_ERRBUF_SIZE,
"bind: %s", pcap_strerror(err));
return -2;
return 0;
}
return 0;
return 1;
}
/*

5
pcap.c
View File

@ -33,7 +33,7 @@
#ifndef lint
static const char rcsid[] _U_ =
"@(#) $Header: /tcpdump/master/libpcap/pcap.c,v 1.122 2008-05-26 19:58:06 guy Exp $ (LBL)";
"@(#) $Header: /tcpdump/master/libpcap/pcap.c,v 1.123 2008-07-01 08:02:33 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
@ -951,6 +951,9 @@ pcap_statustostr(int errnum)
case PCAP_ERROR_PERM_DENIED:
return ("You don't have permission to capture on that device");
case PCAP_ERROR_IFACE_NOT_UP:
return ("That device is not up");
}
(void)snprintf(ebuf, sizeof ebuf, "Unknown error: %d", errnum);
return(ebuf);

3
pcap/pcap.h
View File

@ -31,7 +31,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#) $Header: /tcpdump/master/libpcap/pcap/pcap.h,v 1.13 2008-05-30 01:35:33 guy Exp $ (LBL)
* @(#) $Header: /tcpdump/master/libpcap/pcap/pcap.h,v 1.14 2008-07-01 08:02:33 guy Exp $ (LBL)
*/
#ifndef lib_pcap_pcap_h
@ -243,6 +243,7 @@ typedef void (*pcap_handler)(u_char *, const struct pcap_pkthdr *,
#define PCAP_ERROR_RFMON_NOTSUP -6 /* this device doesn't support rfmon (monitor) mode */
#define PCAP_ERROR_NOT_RFMON -7 /* operation supported only in monitor mode */
#define PCAP_ERROR_PERM_DENIED -8 /* no permission to open the device */
#define PCAP_ERROR_IFACE_NOT_UP -9 /* interface isn't up */
/*
* Warning codes for the pcap API.

8
pcap_activate.3pcap
View File

@ -1,4 +1,4 @@
.\" @(#) $Header: /tcpdump/master/libpcap/pcap_activate.3pcap,v 1.4 2008-04-09 21:26:12 guy Exp $
.\" @(#) $Header: /tcpdump/master/libpcap/pcap_activate.3pcap,v 1.5 2008-07-01 08:02:33 guy Exp $
.\"
.\" Copyright (c) 1994, 1996, 1997
.\" The Regents of the University of California. All rights reserved.
@ -54,9 +54,11 @@ exist,
if the process doesn't have permission to open the capture source,
.B PCAP_ERROR_RFMON_NOTSUP
if monitor mode was specified but the capture source doesn't support
monitor mode, and
monitor mode,
.B PCAP_ERROR_IFACE_NOT_UP
if the capture source is not up, and
.B PCAP_ERROR
if an error occurred.
if another error occurred.
If
.B PCAP_WARNING
or