Fix a logical error in T/TCP: when we actively open a connection, we

have to decide whether to send a CC or CCnew option in our SYN segment
depending on the contents of our TAO cache.  This decision has to be
made once when the connection starts.  The earlier code delayed this
decision until the segment was assembled in tcp_output() and
retransmitted SYN segments could have different CC options.

Reviewed by:	Richard Stevens, davidg, wollman

3 files changed, 25 insertions, 12 deletions

diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
index 9afaf97..f238761 100644
--- a/sys/netinet/tcp_output.c
+++ b/sys/netinet/tcp_output.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)tcp_output.c	8.4 (Berkeley) 5/24/95
- *	$Id: tcp_output.c,v 1.14 1995/09/22 20:05:58 wollman Exp $
+ *	$Id: tcp_output.c,v 1.15 1995/10/16 18:21:12 wollman Exp $
  */
 
 #include <sys/param.h>
@@ -384,15 +384,8 @@ send:
 		case TH_SYN:
 			opt[optlen++] = TCPOPT_NOP;
 			opt[optlen++] = TCPOPT_NOP;
-
-			if (taop->tao_ccsent != 0 &&
-			    CC_GEQ(tp->cc_send, taop->tao_ccsent)) {
-				opt[optlen++] = TCPOPT_CC;
-				taop->tao_ccsent = tp->cc_send;
-			} else {
-				opt[optlen++] = TCPOPT_CCNEW;
-				taop->tao_ccsent = 0;
-			}
+			opt[optlen++] = tp->t_flags & TF_SENDCCNEW ?
+						TCPOPT_CCNEW : TCPOPT_CC;
 			opt[optlen++] = TCPOLEN_CC;
 			*(u_int32_t *)&opt[optlen] = htonl(tp->cc_send);
  			optlen += 4;
diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c
index ab4c5c9..1b05f16 100644
--- a/sys/netinet/tcp_usrreq.c
+++ b/sys/netinet/tcp_usrreq.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	From: @(#)tcp_usrreq.c	8.2 (Berkeley) 1/3/94
- *	$Id: tcp_usrreq.c,v 1.16 1995/09/13 17:54:03 wollman Exp $
+ *	$Id: tcp_usrreq.c,v 1.17 1995/10/29 21:30:25 olah Exp $
  */
 
 #include <sys/param.h>
@@ -407,6 +407,8 @@ tcp_connect(tp, nam)
 	struct sockaddr_in *sin = mtod(nam, struct sockaddr_in *);
 	struct sockaddr_in *ifaddr;
 	int error;
+	struct rmxp_tao *taop;
+	struct rmxp_tao tao_noncached;
 
 	if (inp->inp_lport == 0) {
 		error = in_pcbbind(inp, NULL);
@@ -459,7 +461,24 @@ tcp_connect(tp, nam)
 	tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
 	tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2;
 	tcp_sendseqinit(tp);
+
+	/*
+	 * Generate a CC value for this connection and
+	 * check whether CC or CCnew should be used.
+	 */
+	if ((taop = tcp_gettaocache(tp->t_inpcb)) == NULL) {
+		taop = &tao_noncached;
+		bzero(taop, sizeof(*taop));
+	}
+
 	tp->cc_send = CC_INC(tcp_ccgen);
+	if (taop->tao_ccsent != 0 &&
+	    CC_GEQ(tp->cc_send, taop->tao_ccsent)) {
+		taop->tao_ccsent = tp->cc_send;
+	} else {
+		taop->tao_ccsent = 0;
+		tp->t_flags |= TF_SENDCCNEW;
+	}
 
 	return 0;
 }
diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
index 0a1ce27..595d639 100644
--- a/sys/netinet/tcp_var.h
+++ b/sys/netinet/tcp_var.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)tcp_var.h	8.4 (Berkeley) 5/24/95
- * 	$Id: tcp_var.h,v 1.20 1995/10/12 17:37:25 wollman Exp $
+ * 	$Id: tcp_var.h,v 1.21 1995/10/16 18:21:26 wollman Exp $
  */
 
 #ifndef _NETINET_TCP_VAR_H_
@@ -70,6 +70,7 @@ struct tcpcb {
 #define TF_NOPUSH	0x1000		/* don't push */
 #define TF_REQ_CC	0x2000		/* have/will request CC */
 #define	TF_RCVD_CC	0x4000		/* a CC was received in SYN */
+#define TF_SENDCCNEW	0x8000		/* send CCnew instead of CC in SYN */
 
 	struct	tcpiphdr *t_template;	/* skeletal packet for transmit */
 	struct	inpcb *t_inpcb;		/* back pointer to internet pcb */