On Fri, Aug 30, 2002 at 03:43:45PM -0700, B. James Phillippe (spamblock) wrote:

 >     /*
 >      * Verify the sequence and ack numbers.  Try getting the correct
 >      * response again.
 >      */
 >     if ((th->th_ack != sc->sc_iss + 1) ||
 >         SEQ_LEQ(th->th_seq, sc->sc_irs) ||
 >         SEQ_GT(th->th_seq, sc->sc_irs + 1 + sc->sc_win)) {
 >         (void) syn_cache_respond(sc, m);
 >         splx(s);
 >         return ((struct socket *)(-1));
 >     }
 > 
 > If syn_cache_get() is only ever called for packets which have TH_ACK set
 > without TH_SYN and without TH_RST set, th->th_seq should always be 0,
 > correct?  Is there a purpose for the tests of th->th_seq?

See RFC793, section 3.4.

-- 
        -- Jason R. Thorpe <thorpej@wasabisystems.com>