diff options
| -rw-r--r-- | netsniff-ng.c | 32 |
1 files changed, 22 insertions, 10 deletions
diff --git a/netsniff-ng.c b/netsniff-ng.c index 8d22151..4cfabc1 100644 --- a/netsniff-ng.c +++ b/netsniff-ng.c @@ -55,7 +55,7 @@ enum dump_mode { struct ctx { char *device_in, *device_out, *device_trans, *filter, *prefix; - int cpu, rfraw, dump, print_mode, dump_dir, packet_type; + int cpu, rfraw, dump, print_mode, dump_dir, packet_type, lo_ifindex; unsigned long kpull, dump_interval, tx_bytes, tx_packets; size_t reserve_size; bool randomize, promiscuous, enforce, jumbo, dump_bpf, hwtimestamp, verbose; @@ -410,6 +410,18 @@ out: printf("\r%12lu sec, %lu usec in total\n", diff.tv_sec, diff.tv_usec); } +static inline bool skip_packet(struct ctx *ctx, struct sockaddr_ll *sll) +{ + if (ctx->packet_type != -1) + return ctx->packet_type != sll->sll_pkttype; + + /* when receving from the loopback device, each packet is seen twice, + * so drop the outgoing ones to avoid duplicates + */ + return (sll->sll_ifindex == ctx->lo_ifindex) && + (sll->sll_pkttype == PACKET_OUTGOING); +} + static void receive_to_xmit(struct ctx *ctx) { short ifflags = 0; @@ -470,9 +482,8 @@ static void receive_to_xmit(struct ctx *ctx) ctx->pkts_seen++; - if (ctx->packet_type != -1) - if (ctx->packet_type != hdr_in->s_ll.sll_pkttype) - goto next; + if (skip_packet(ctx, &hdr_in->s_ll)) + goto next; hdr_out = tx_ring.frames[it_out].iov_base; out = ((uint8_t *) hdr_out) + TPACKET2_HDRLEN - sizeof(struct sockaddr_ll); @@ -942,9 +953,8 @@ static void walk_t3_block(struct block_desc *pbd, struct ctx *ctx, uint8_t *packet = ((uint8_t *) hdr + hdr->tp_mac); pcap_pkthdr_t phdr; - if (ctx->packet_type != -1) - if (ctx->packet_type != sll->sll_pkttype) - goto next; + if (skip_packet(ctx, sll)) + goto next; ctx->pkts_seen++; @@ -1071,9 +1081,8 @@ static void recv_only_or_dump(struct ctx *ctx) uint8_t *packet = ((uint8_t *) hdr) + hdr->tp_h.tp_mac; pcap_pkthdr_t phdr; - if (ctx->packet_type != -1) - if (ctx->packet_type != hdr->s_ll.sll_pkttype) - goto next; + if (skip_packet(ctx, &hdr->s_ll)) + goto next; ctx->pkts_seen++; @@ -1523,6 +1532,9 @@ int main(int argc, char **argv) if (!ctx.device_in) ctx.device_in = xstrdup("any"); + if (!strcmp(ctx.device_in, "any") || !strcmp(ctx.device_in, "lo")) + ctx.lo_ifindex = device_ifindex("lo"); + register_signal(SIGINT, signal_handler); register_signal(SIGQUIT, signal_handler); register_signal(SIGTERM, signal_handler); |