diff options
Diffstat (limited to 'pcap-linux.c')
| -rw-r--r-- | pcap-linux.c | 74 |
1 files changed, 44 insertions, 30 deletions
diff --git a/pcap-linux.c b/pcap-linux.c index 183dd639..b0a0dd91 100644 --- a/pcap-linux.c +++ b/pcap-linux.c @@ -310,6 +310,7 @@ struct pcap_linux { u_int tp_version; /* version of tpacket_hdr for mmaped ring */ u_int tp_hdrlen; /* hdrlen of tpacket_hdr for mmaped ring */ u_char *oneshot_buffer; /* buffer for copy of packet */ + int poll_timeout; /* timeout to use in poll() */ #ifdef HAVE_TPACKET3 unsigned char *current_packet; /* Current packet within the TPACKET_V3 block. Move to next block if NULL. */ int packets_left; /* Unhandled packets left within the block from previous call to pcap_read_linux_mmap_v3 in case of TPACKET_V3. */ @@ -1293,6 +1294,42 @@ static void pcap_cleanup_linux( pcap_t *handle ) } /* + * Set the timeout to be used in poll() with memory-mapped packet capture. + */ +static void +set_poll_timeout(struct pcap_linux *handlep) +{ + if (handlep->timeout == 0) { +#ifdef HAVE_TPACKET3 + /* + * XXX - due to a set of (mis)features in the + * TPACKET_V3 kernel code, blocking forever with + * a TPACKET_V3 socket can, if few packets + * are arriving and passing the socket filter, + * cause most packets to be dropped. See + * libpcap issue #335 for the full painful + * story. The workaround is to have poll() + * time out very quickly, so we grab the + * frames handed to us, and return them to + * the kernel, ASAP. + * + * If those issues are ever fixed, we might + * want to check the kernel version and block + * forever with TPACKET_V3 if we're running + * with a kernel that has the fix. + */ + if (handlep->tp_version == TPACKET_V3) + handlep->poll_timeout = 1; /* don't block for very long */ + else +#endif + handlep->poll_timeout = -1; /* block forever */ + } else if (handlep->timeout > 0) + handlep->poll_timeout = handlep->timeout; /* block for that amount of time */ + else + handlep->poll_timeout = 0; /* non-blocking mode - poll to pick up errors */ +} + +/* * Get a handle for a live capture from the given device. You can * pass NULL as device to get all packages (without link level * information of course). If you pass 1 as promisc the interface @@ -1402,7 +1439,11 @@ pcap_activate_linux(pcap_t *handle) * set to the status to return, * which might be 0, or might be * a PCAP_WARNING_ value. + * + * Set the timeout to use in poll() before + * returning. */ + set_poll_timeout(handlep); return status; case 0: @@ -4299,6 +4340,8 @@ pcap_setnonblock_mmap(pcap_t *p, int nonblock, char *errbuf) handlep->timeout = ~handlep->timeout; } } + /* Update the timeout to use in poll(). */ + set_poll_timeout(handlep); return 0; } @@ -4347,7 +4390,6 @@ static int pcap_wait_for_frames_mmap(pcap_t *handle) { if (!pcap_get_ring_frame(handle, TP_STATUS_USER)) { struct pcap_linux *handlep = handle->priv; - int timeout; char c; struct pollfd pollinfo; int ret; @@ -4355,36 +4397,8 @@ static int pcap_wait_for_frames_mmap(pcap_t *handle) pollinfo.fd = handle->fd; pollinfo.events = POLLIN; - if (handlep->timeout == 0) { -#ifdef HAVE_TPACKET3 - /* - * XXX - due to a set of (mis)features in the - * TPACKET_V3 kernel code, blocking forever with - * a TPACKET_V3 socket can, if few packets - * are arriving and passing the socket filter, - * cause most packets to be dropped. See - * libpcap issue #335 for the full painful - * story. The workaround is to have poll() - * time out very quickly, so we grab the - * frames handed to us, and return them to - * the kernel, ASAP. - * - * If those issues are ever fixed, we might - * want to check the kernel version and block - * forever with TPACKET_V3 if we're running - * with a kernel that has the fix. - */ - if (handlep->tp_version == TPACKET_V3) - timeout = 1; /* don't block for very long */ - else -#endif - timeout = -1; /* block forever */ - } else if (handlep->timeout > 0) - timeout = handlep->timeout; /* block for that amount of time */ - else - timeout = 0; /* non-blocking mode - poll to pick up errors */ do { - ret = poll(&pollinfo, 1, timeout); + ret = poll(&pollinfo, 1, handlep->poll_timeout); if (ret < 0 && errno != EINTR) { snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "can't poll on packet socket: %s", |