10409 ipf sometimes freezes RFC 1323 transfers
Reviewed by: Jason King <jbk@joyent.com>

*** 1727,1737 ****
                          if ((fin->fin_out != 0) && (is->is_pass & FR_NEWISN))
                                  fr_checknewisn(fin, is);
                  } else if (flags == TH_SYN) {
                          is->is_s0[source] = ntohl(tcp->th_seq) + 1;
                          if ((TCP_OFF(tcp) > (sizeof(tcphdr_t) >> 2)))
!                                 (void) fr_tcpoptions(fin, tcp, tdata);
  
                          if ((fin->fin_out != 0) && (is->is_pass & FR_NEWISN))
                                  fr_checknewisn(fin, is);
  
                  }
--- 1727,1737 ----
                          if ((fin->fin_out != 0) && (is->is_pass & FR_NEWISN))
                                  fr_checknewisn(fin, is);
                  } else if (flags == TH_SYN) {
                          is->is_s0[source] = ntohl(tcp->th_seq) + 1;
                          if ((TCP_OFF(tcp) > (sizeof(tcphdr_t) >> 2)))
!                                 (void) fr_tcpoptions(fin, tcp, fdata);
  
                          if ((fin->fin_out != 0) && (is->is_pass & FR_NEWISN))
                                  fr_checknewisn(fin, is);
  
                  }
*** 1838,1847 ****
--- 1838,1848 ----
           * SYN), we can assume that the receiver of the SYN did
           * already send back the SYN/ACK (and thus that we know if
           * the receiver also does window scaling)
           */
          if (!(tcpflags & TH_SYN) && (fdata->td_winflags & TCP_WSCALE_FIRST)) {
+                 fdata->td_winflags &= ~TCP_WSCALE_FIRST;
                  fdata->td_maxwin = win;
          }
  
          end = seq + dsize;
  
*** 1900,1910 ****
                   */
              (SEQ_GE(seq, fdata->td_end - maxwin)) &&
  #endif
  /* XXX what about big packets */
  #define MAXACKWINDOW 66000
!             (-ackskew <= (MAXACKWINDOW << fdata->td_winscale)) &&
              ( ackskew <= (MAXACKWINDOW << fdata->td_winscale))) {
                  inseq = 1;
          /*
           * Microsoft Windows will send the next packet to the right of the
           * window if SACK is in use.
--- 1901,1911 ----
                   */
              (SEQ_GE(seq, fdata->td_end - maxwin)) &&
  #endif
  /* XXX what about big packets */
  #define MAXACKWINDOW 66000
!             (-ackskew <= (MAXACKWINDOW)) &&
              ( ackskew <= (MAXACKWINDOW << fdata->td_winscale))) {
                  inseq = 1;
          /*
           * Microsoft Windows will send the next packet to the right of the
           * window if SACK is in use.