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pping: Only match TSecr in ACKs

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The echoed TCP timestamp (TSecr) is only valid if the ACK flag is
set. So make sure to only attempt to match on ACK packets.

Signed-off-by: Simon Sundberg <simon.sundberg@kau.se>
This commit is contained in:
Simon Sundberg
2021-06-21 10:51:20 +02:00
parent c14f52a4d4
commit af5e660d8e
2 changed files with 6 additions and 0 deletions
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4
pping/pping_kern.c
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@@ -153,6 +153,10 @@ static int parse_tcp_identifier(struct parsing_context *ctx, __be16 *sport,
!tcph->syn)
return -1;
// Do not match on non-ACKs (TSecr not valid)
if (!ctx->is_egress && !tcph->ack)
return -1;
// Check if connection is opening/closing
if (tcph->syn) {
fei->event = FLOW_EVENT_OPENING;