xnu-344.21.73.tar.gz

[apple/xnu.git] / bsd / netinet / tcp_output.c

diff --git a/bsd/netinet/tcp_output.c b/bsd/netinet/tcp_output.c
index d3e5558d3b0bffd068c7a4320238411df2ddfe1b..2bfc95262f584e1f9dd87561cf61558b5db69506 100644 (file)
--- a/bsd/netinet/tcp_output.c
+++ b/bsd/netinet/tcp_output.c
@@ -3,19 +3,22 @@
  *
  * @APPLE_LICENSE_HEADER_START@
  * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
  * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
  * 
  * @APPLE_LICENSE_HEADER_END@
  */
@@ -113,7 +116,7 @@ int ss_fltsz = 1;
 SYSCTL_INT(_net_inet_tcp, OID_AUTO, slowstart_flightsize, CTLFLAG_RW,
        &ss_fltsz, 1, "Slow start flight size");
 
-int ss_fltsz_local = TCP_MAXWIN;               /* something large */
+int ss_fltsz_local = 4; /* starts with four segments max */
 SYSCTL_INT(_net_inet_tcp, OID_AUTO, local_slowstart_flightsize, CTLFLAG_RW,
        &ss_fltsz_local, 1, "Slow start flight size for local networks");
 
@@ -129,6 +132,8 @@ struct      mbuf *m_copym_with_hdrs __P((struct mbuf*, int, int, int, struct mbuf**,
 extern int ipsec_bypass;
 #endif
 
+extern int slowlink_wsize;     /* window correction for slow links */
+
 /*
  * Tcp output routine: figure out what should be sent and send it.
  */
@@ -219,6 +224,8 @@ again:
        sendalot = 0;
        off = tp->snd_nxt - tp->snd_una;
        win = min(tp->snd_wnd, tp->snd_cwnd);
+       if (tp->t_flags & TF_SLOWLINK && slowlink_wsize > 0)
+               win = min(win, slowlink_wsize);
 
        flags = tcp_outflags[tp->t_state];
        /*
@@ -325,7 +332,10 @@ again:
        if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc))
                flags &= ~TH_FIN;
 
-       win = sbspace(&so->so_rcv);
+       if (tp->t_flags & TF_SLOWLINK && slowlink_wsize > 0 )   /* Clips window size for slow links */
+               win = min(sbspace(&so->so_rcv), slowlink_wsize);
+       else
+               win = sbspace(&so->so_rcv);
 
        /*
         * Sender silly window avoidance.  If connection is idle
@@ -795,9 +805,17 @@ send:
                win = 0;
        if (win < (long)(tp->rcv_adv - tp->rcv_nxt))
                win = (long)(tp->rcv_adv - tp->rcv_nxt);
-       if (win > (long)TCP_MAXWIN << tp->rcv_scale)
+       if (tp->t_flags & TF_SLOWLINK && slowlink_wsize > 0) {
+               if (win > (long)slowlink_wsize) 
+                       win = slowlink_wsize;
+               th->th_win = htons((u_short) (win>>tp->rcv_scale));
+       }
+       else {
+
+               if (win > (long)TCP_MAXWIN << tp->rcv_scale)
                win = (long)TCP_MAXWIN << tp->rcv_scale;
-       th->th_win = htons((u_short) (win>>tp->rcv_scale));
+               th->th_win = htons((u_short) (win>>tp->rcv_scale));
+       }
        if (SEQ_GT(tp->snd_up, tp->snd_nxt)) {
                th->th_urp = htons((u_short)(tp->snd_up - tp->snd_nxt));
                th->th_flags |= TH_URG;