X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=sys%2Fsrc%2F9%2Fip%2Ftcp.c;h=f241a5c8ef775e7ec9adbe76f47da67893fd44d5;hb=ccf72da47d29772af51b0b348d2845fbbbd8a881;hp=d1addc9d76444aa7bd7316715ba645b10f6aad3f;hpb=98f47d5867cbbaa06f2c9080c301c9191e196205;p=plan9front.git

diff --git a/sys/src/9/ip/tcp.c b/sys/src/9/ip/tcp.c
index d1addc9d7..f241a5c8e 100644
--- a/sys/src/9/ip/tcp.c
+++ b/sys/src/9/ip/tcp.c
@@ -47,7 +47,7 @@ enum
 	MSL2		= 10,
 	MSPTICK		= 50,		/* Milliseconds per timer tick */
 	DEF_MSS		= 1460,		/* Default maximum segment */
-	DEF_MSS6	= 1280,		/* Default maximum segment (min) for v6 */
+	DEF_MSS6	= 1220,		/* Default maximum segment (min) for v6 */
 	DEF_RTT		= 500,		/* Default round trip */
 	DEF_KAT		= 120000,	/* Default time (ms) between keep alives */
 	TCP_LISTEN	= 0,		/* Listen connection */
@@ -846,32 +846,37 @@ localclose(Conv *s, char *reason)	/* called with tcb locked */
 
 /* mtu (- TCP + IP hdr len) of 1st hop */
 static int
-tcpmtu(Proto *tcp, uchar *addr, int version, uint *scale)
+tcpmtu(Route *r, int version, uint *scale)
 {
 	Ipifc *ifc;
 	int mtu;
 
-	ifc = findipifc(tcp->f, addr, 0);
-	switch(version){
-	default:
-	case V4:
-		mtu = DEF_MSS;
-		if(ifc != nil)
-			mtu = ifc->maxtu - ifc->m->hsize - (TCP4_PKT + TCP4_HDRSIZE);
-		break;
-	case V6:
-		mtu = DEF_MSS6;
-		if(ifc != nil)
-			mtu = ifc->maxtu - ifc->m->hsize - (TCP6_PKT + TCP6_HDRSIZE);
-		break;
-	}
 	/*
 	 * set the ws.  it doesn't commit us to anything.
 	 * ws is the ultimate limit to the bandwidth-delay product.
 	 */
 	*scale = Defadvscale;
 
-	return mtu;
+	/*
+	 * currently we do not implement path MTU discovery
+	 * so use interface MTU *only* if directly reachable
+	 * or when we use V4 which allows routers to fragment.
+	 * otherwise, we use the default MSS which assumes a
+	 * safe minimum MTU of 1280 bytes for V6.
+	 */  
+	if(r != nil){
+		ifc = r->ifc;
+		mtu = ifc->maxtu - ifc->m->hsize;
+		if(version == V4)
+			return mtu - (TCP4_PKT + TCP4_HDRSIZE);
+		mtu -= TCP6_PKT + TCP6_HDRSIZE;
+		if((r->type & (Rifc|Runi)) != 0 || mtu <= DEF_MSS6)
+			return mtu;
+	}
+	if(version == V6)
+		return DEF_MSS6;
+	else
+		return DEF_MSS;
 }
 
 static void
@@ -1034,14 +1039,10 @@ htontcp6(Tcp *tcph, Block *data, Tcp6hdr *ph, Tcpctl *tcb)
 	if(data) {
 		dlen = blocklen(data);
 		data = padblock(data, hdrlen + TCP6_PKT);
-		if(data == nil)
-			return nil;
 	}
 	else {
 		dlen = 0;
 		data = allocb(hdrlen + TCP6_PKT + 64);	/* the 64 pad is to meet mintu's */
-		if(data == nil)
-			return nil;
 		data->wp += hdrlen + TCP6_PKT;
 	}
 
@@ -1118,14 +1119,10 @@ htontcp4(Tcp *tcph, Block *data, Tcp4hdr *ph, Tcpctl *tcb)
 	if(data) {
 		dlen = blocklen(data);
 		data = padblock(data, hdrlen + TCP4_PKT);
-		if(data == nil)
-			return nil;
 	}
 	else {
 		dlen = 0;
 		data = allocb(hdrlen + TCP4_PKT + 64);	/* the 64 pad is to meet mintu's */
-		if(data == nil)
-			return nil;
 		data->wp += hdrlen + TCP4_PKT;
 	}
 
@@ -1317,7 +1314,7 @@ tcpsndsyn(Conv *s, Tcpctl *tcb)
 	tcb->sndsyntime = NOW;
 
 	/* set desired mss and scale */
-	tcb->mss = tcpmtu(s->p, s->laddr, s->ipversion, &tcb->scale);
+	tcb->mss = tcpmtu(v6lookup(s->p->f, s->raddr, s), s->ipversion, &tcb->scale);
 	tpriv = s->p->priv;
 	tpriv->stats[Mss] = tcb->mss;
 }
@@ -1495,7 +1492,7 @@ sndsynack(Proto *tcp, Limbo *lp)
 	seg.ack = lp->irs+1;
 	seg.flags = SYN|ACK;
 	seg.urg = 0;
-	seg.mss = tcpmtu(tcp, lp->laddr, lp->version, &scale);
+	seg.mss = tcpmtu(v6lookup(tcp->f, lp->raddr, nil), lp->version, &scale);
 	seg.wnd = QMAX;
 
 	/* if the other side set scale, we should too */
@@ -1770,11 +1767,13 @@ tcpincoming(Conv *s, Tcp *segp, uchar *src, uchar *dst, uchar version)
 	tcb->flgcnt = 0;
 	tcb->flags |= SYNACK;
 
+	/* set desired mss and scale */
+	tcb->mss = tcpmtu(v6lookup(s->p->f, src, s), version, &tcb->scale);
+
 	/* our sending max segment size cannot be bigger than what he asked for */
-	if(lp->mss != 0 && lp->mss < tcb->mss) {
+	if(lp->mss != 0 && lp->mss < tcb->mss)
 		tcb->mss = lp->mss;
-		tpriv->stats[Mss] = tcb->mss;
-	}
+	tpriv->stats[Mss] = tcb->mss;
 
 	/* window scaling */
 	tcpsetscale(new, tcb, lp->rcvscale, lp->sndscale);
@@ -2435,10 +2434,7 @@ reset:
 				 * receive queue
 				 */
 				if(bp) {
-					bp = packblock(bp);
-					if(bp == nil)
-						panic("tcp packblock");
-					qpassnolim(s->rq, bp);
+					qpassnolim(s->rq, packblock(bp));
 					bp = nil;
 				}
 				tcb->rcv.nxt += length;
@@ -3252,6 +3248,8 @@ tcpadvise(Proto *tcp, Block *bp, char *msg)
 		if(tcb->state != Closed)
 		if(ipcmp(s->raddr, dest) == 0)
 		if(ipcmp(s->laddr, source) == 0){
+			if(s->ignoreadvice)
+				break;
 			qlock(s);
 			qunlock(tcp);
 			switch(tcb->state){
@@ -3284,6 +3282,8 @@ tcpporthogdefensectl(char *val)
 static char*
 tcpctl(Conv* c, char** f, int n)
 {
+	if(n == 1 && strcmp(f[0], "close") == 0)
+		return tcpclose(c), nil;
 	if(n == 1 && strcmp(f[0], "hangup") == 0)
 		return tcphangup(c);
 	if(n >= 1 && strcmp(f[0], "keepalive") == 0)