diff options
Diffstat (limited to 'epan')
| -rw-r--r-- | epan/dissectors/packet-tcp.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/epan/dissectors/packet-tcp.c b/epan/dissectors/packet-tcp.c index ba1ebff815..44cf550364 100644 --- a/epan/dissectors/packet-tcp.c +++ b/epan/dissectors/packet-tcp.c @@ -3071,10 +3071,33 @@ again: if (tcpd) { /* Have we seen this PDU before (and is it the start of a multi- * segment PDU)? + * + * If the sequence number was seen before, it is part of a + * retransmission if the whole segment fits within the MSP. + * (But if this is this frame was already visited and the first frame of + * the MSP matches the current frame, then it is not a retransmission, + * but the start of a new MSP.) + * + * If only part of the segment fits in the MSP, then either: + * - The previous segment included with the MSP was a Zero Window Probe + * with one byte of data and the subdissector just asked for one more + * byte. Do not mark it as retransmission (Bug 15427). + * - Data was actually being retransmitted, but with additional data + * (Bug 13523). Do not mark it as retransmission to handle the extra + * bytes. (NOTE Due to the TCP_A_RETRANSMISSION check below, such + * extra data will still be ignored.) + * - The MSP contains multiple segments, but the subdissector finished + * reassembly using a subset of the final segment (thus "msp->nxtpdu" + * is smaller than the nxtseq of the previous segment). If that final + * segment was retransmitted, then "nxtseq > msp->nxtpdu". + * Unfortunately that will *not* be marked as retransmission here. + * The next TCP_A_RETRANSMISSION hopefully takes care of it though. + * * Only shortcircuit here when the first segment of the MSP is known, * and when this this first segment is not one to complete the MSP. */ if ((msp = (struct tcp_multisegment_pdu *)wmem_tree_lookup32(tcpd->fwd->multisegment_pdus, seq)) && + nxtseq <= msp->nxtpdu && !(msp->flags & MSP_FLAGS_MISSING_FIRST_SEGMENT) && msp->last_frame != pinfo->num) { const char* str; gboolean is_retransmission = FALSE; |