silly-window: send full-sized packets only, or we start sending

funny sizes; don't decrement seq for FIN when retransmitting; rearrange code
to set rtseq properly on SYN (was one too high); don't clear rxtshft
when persist tops out

SCCS-vsn: sys/netinet/tcp_output.c 7.6

diff --git a/usr/src/sys/netinet/tcp_output.c b/usr/src/sys/netinet/tcp_output.c
index fe80a79..241fbd8 100644 (file)
--- a/usr/src/sys/netinet/tcp_output.c
+++ b/usr/src/sys/netinet/tcp_output.c
@@ -3,7 +3,7 @@
  * All rights reserved.  The Berkeley software License Agreement
  * specifies the terms and conditions for redistribution.
  *
  * All rights reserved.  The Berkeley software License Agreement
  * specifies the terms and conditions for redistribution.
  *

- *     @(#)tcp_output.c        7.5 (Berkeley) %G%
+ *     @(#)tcp_output.c        7.6 (Berkeley) %G%

  */
 
 #include "param.h"
  */
 
 #include "param.h"


@@ -143,7 +143,7 @@ again:
         * to send into a small window), then must resend.
         */
        if (len) {
         * to send into a small window), then must resend.
         */
        if (len) {

-               if (len == tp->t_maxseg || len >= TCP_MSS)      /* a lot */
+               if (len == tp->t_maxseg)

                        goto send;
                if ((idle || tp->t_flags & TF_NODELAY) &&
                    len + off >= so->so_snd.sb_cc)
                        goto send;
                if ((idle || tp->t_flags & TF_NODELAY) &&
                    len + off >= so->so_snd.sb_cc)


@@ -242,7 +242,8 @@ send:
         * window for use in delaying messages about window sizes.
         * If resending a FIN, be sure not to use a new sequence number.
         */
         * window for use in delaying messages about window sizes.
         * If resending a FIN, be sure not to use a new sequence number.
         */

-       if (flags & TH_FIN && tp->t_flags & TF_SENTFIN && len == 0)
+       if (flags & TH_FIN && tp->t_flags & TF_SENTFIN && 
+           tp->snd_nxt == tp->snd_max)

                tp->snd_nxt--;
        ti->ti_seq = htonl(tp->snd_nxt);
        ti->ti_ack = htonl(tp->rcv_nxt);
                tp->snd_nxt--;
        ti->ti_seq = htonl(tp->snd_nxt);
        ti->ti_ack = htonl(tp->rcv_nxt);


@@ -327,6 +328,15 @@ send:
         * the retransmit.  In persist state, just set snd_max.
         */
        if (tp->t_force == 0 || tp->t_timer[TCPT_PERSIST] == 0) {
         * the retransmit.  In persist state, just set snd_max.
         */
        if (tp->t_force == 0 || tp->t_timer[TCPT_PERSIST] == 0) {

+               /*
+                * Time this transmission if not a retransmission and
+                * not currently timing anything.
+                */
+               if (tp->t_rtt == 0 && tp->snd_nxt == tp->snd_max) {
+                       tp->t_rtt = 1;
+                       tp->t_rtseq = tp->snd_nxt;
+                       tcpstat.tcps_segstimed++;
+               }

                /*
                 * Advance snd_nxt over sequence space of this segment.
                 */
                /*
                 * Advance snd_nxt over sequence space of this segment.
                 */


@@ -337,18 +347,8 @@ send:
                        tp->t_flags |= TF_SENTFIN;
                }
                tp->snd_nxt += len;
                        tp->t_flags |= TF_SENTFIN;
                }
                tp->snd_nxt += len;

-               if (SEQ_GT(tp->snd_nxt, tp->snd_max)) {
+               if (SEQ_GT(tp->snd_nxt, tp->snd_max))

                        tp->snd_max = tp->snd_nxt;
                        tp->snd_max = tp->snd_nxt;

-                       /*
-                        * Time this transmission if not a retransmission and
-                        * not currently timing anything.
-                        */
-                       if (tp->t_rtt == 0) {
-                               tp->t_rtt = 1;
-                               tp->t_rtseq = tp->snd_nxt - len;
-                               tcpstat.tcps_segstimed++;
-                       }
-               }

 
                /*
                 * Set retransmit timer if not currently set,
 
                /*
                 * Set retransmit timer if not currently set,


@@ -412,8 +412,7 @@ tcp_setpersist(tp)
         */
        TCPT_RANGESET(tp->t_timer[TCPT_PERSIST],
            ((int)(tcp_beta * tp->t_srtt)) << tp->t_rxtshift,
         */
        TCPT_RANGESET(tp->t_timer[TCPT_PERSIST],
            ((int)(tcp_beta * tp->t_srtt)) << tp->t_rxtshift,

-           TCPTV_PERSMIN, TCPTV_MAX);
-       tp->t_rxtshift++;
-       if (tp->t_rxtshift >= TCP_MAXRXTSHIFT)
-               tp->t_rxtshift = 0;
+           TCPTV_PERSMIN, TCPTV_PERSMAX);
+       if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
+               tp->t_rxtshift++;

 }
 }