diff options
Diffstat (limited to 'pcap-linux.c')
| -rw-r--r-- | pcap-linux.c | 63 |
1 files changed, 49 insertions, 14 deletions
diff --git a/pcap-linux.c b/pcap-linux.c index c5477115..d9f9f10a 100644 --- a/pcap-linux.c +++ b/pcap-linux.c @@ -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; } /* |