cvs commit: src/sys/netinet tcp_input.c

Qing Li qingli at
Wed Mar 7 23:22:00 UTC 2007

qingli      2007-03-07 23:21:59 UTC

  FreeBSD src repository

  Modified files:
    sys/netinet          tcp_input.c 
  This patch is provided to fix a couple of deployment issues observed
  in the field. In one situation, one end of the TCP connection sends
  a back-to-back RST packet, with delayed ack, the last_ack_sent variable
  has not been update yet. When tcp_insecure_rst is turned off, the code
  treats the RST as invalid because last_ack_sent instead of rcv_nxt is
  compared against th_seq. Apparently there is some kind of firewall that
  sits in between the two ends and that RST packet is the only RST
  packet received. With short lived HTTP connections, the symptom is
  a large accumulation of connections over a short period of time .
  The +/-(1) factor is to take care of implementations out there that
  generate RST packets with these types of sequence numbers. This
  behavior has also been observed in live environments.
  Reviewed by:    silby, Mike Karels
  MFC after:      1 week
  Revision  Changes    Path
  1.316     +7 -5      src/sys/netinet/tcp_input.c

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