diff options
| -rw-r--r-- | pcap-linux.c | 47 |
1 files changed, 37 insertions, 10 deletions
diff --git a/pcap-linux.c b/pcap-linux.c index 5df804db..36a8e986 100644 --- a/pcap-linux.c +++ b/pcap-linux.c @@ -1667,7 +1667,7 @@ pcap_stats_linux(pcap_t *handle, struct pcap_stat *stats) * the kernel by libpcap, and thus not yet seen by * the application. * - * In "linux/net/packet/af_packet.c", at least in 2.6.26 + * In "linux/net/packet/af_packet.c", at least in 2.6.27 * through 5.6 kernels, "tp_packets" is incremented for * every packet that passes the packet filter *and* is * successfully copied to the ring buffer; "tp_drops" is @@ -3151,19 +3151,32 @@ init_tpacket(pcap_t *handle, int version, const char *version_str) /* * EINVAL means this specific version of TPACKET * is not supported. Tell the caller they can try - * with a different one. + * with a different one; if they've run out of + * others to try, let them set the error message + * appropriately. */ - pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE, errno, - "kernel doesn't support %s sockets;\n" - "it's either too old or built without PACKET_MMAP support", - version_str); return 1; } - /* Failed to even find out; this is a fatal error. */ - pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE, - errno, "can't get %s header len on packet socket", - version_str); + /* + * All other errors are fatal. + */ + if (errno == ENOPROTOOPT) { + /* + * PACKET_HDRLEN isn't supported, which means + * that memory-mapped capture isn't supported. + * Indicate that in the message. + */ + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "Kernel doesn't support memory-mapped capture; a 2.6.27 or later 2.x kernel is required, with CONFIG_PACKET_MMAP specified for 2.x kernels"); + } else { + /* + * Some unexpected error. + */ + pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE, + errno, "can't get %s header len on packet socket", + version_str); + } return -1; } handlep->tp_hdrlen = val; @@ -3220,6 +3233,11 @@ prepare_tpacket_socket(pcap_t *handle) */ return -1; } + + /* + * This means it returned 1, which means "the kernel + * doesn't support TPACKET_V3"; try TPACKET_V2. + */ } #endif /* HAVE_TPACKET3 */ @@ -3234,6 +3252,15 @@ prepare_tpacket_socket(pcap_t *handle) return 0; } + if (ret == 1) { + /* + * OK, the kernel supports memory-mapped capture, but + * not TPACKET_V2. Set the error message appropriately. + */ + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "Kernel doesn't support TPACKET_V2; a 2.6.27 or later kernel is required"); + } + /* * We failed. */ |