From b7a44e34864e3b6f122cbfe7e94955adc910a17a Mon Sep 17 00:00:00 2001
From: Garrett Wollman <wollman@FreeBSD.org>
Date: Tue, 5 Dec 1995 17:46:50 +0000
Subject: [PATCH] Path MTU Discovery is now standard.

---
 sys/netinet/in_rmx.c       | 16 ++++++++--------
 sys/netinet/ip_icmp.c      | 14 +++++++-------
 sys/netinet/ip_output.c    |  6 +++---
 sys/netinet/ip_var.h       |  4 +---
 sys/netinet/tcp_output.c   | 12 ++++++------
 sys/netinet/tcp_subr.c     | 10 +++++-----
 sys/netinet/tcp_timewait.c | 10 +++++-----
 sys/netinet/tcp_var.h      |  6 ++----
 8 files changed, 37 insertions(+), 41 deletions(-)

diff --git a/sys/netinet/in_rmx.c b/sys/netinet/in_rmx.c
index 7e8be6ea155..4e9dd2b3002 100644
--- a/sys/netinet/in_rmx.c
+++ b/sys/netinet/in_rmx.c
@@ -26,7 +26,7 @@
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: in_rmx.c,v 1.19 1995/11/14 20:34:06 phk Exp $
+ * $Id: in_rmx.c,v 1.20 1995/12/02 19:37:56 bde Exp $
  */
 
 /*
@@ -65,9 +65,9 @@
 #include <netinet/tcp_seq.h>
 #include <netinet/tcp_timer.h>
 #include <netinet/tcp_var.h>
-#ifndef MTUDISC
+#if 0
 #include <netinet/tcpip.h>
-#endif /* not MTUDISC */
+#endif
 
 extern int	in_inithead __P((void **head, int off));
 extern void	in_rtqdrain __P((void));
@@ -110,22 +110,22 @@ in_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
 	if (!rt->rt_rmx.rmx_recvpipe && !(rt->rt_rmx.rmx_locks & RTV_RPIPE))
 		rt->rt_rmx.rmx_recvpipe = tcp_recvspace;
 
-#ifndef MTUDISC
+#if 0
 	/*
 	 * Finally, set an MTU, again duplicating logic in TCP.
 	 * The in_localaddr() business will go away when we have
 	 * proper PMTU discovery.
 	 */
-#endif /* not MTUDISC */
+#endif
 	if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU) 
 	    && rt->rt_ifp)
-#ifndef MTUDISC
+#if 0
 		rt->rt_rmx.rmx_mtu = (in_localaddr(sin->sin_addr)
 				      ? rt->rt_ifp->if_mtu
 				      : tcp_mssdflt + sizeof(struct tcpiphdr));
-#else /* MTUDISC */
+#else
 		rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
-#endif /* MTUDISC */
+#endif
 
 	return rn_addroute(v_arg, n_arg, head, treenodes);
 }
diff --git a/sys/netinet/ip_icmp.c b/sys/netinet/ip_icmp.c
index 4306b4b3169..5c2c3521ecf 100644
--- a/sys/netinet/ip_icmp.c
+++ b/sys/netinet/ip_icmp.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ip_icmp.c	8.2 (Berkeley) 1/4/94
- * $Id: ip_icmp.c,v 1.11 1995/11/14 20:34:12 phk Exp $
+ * $Id: ip_icmp.c,v 1.12 1995/11/18 13:25:41 bde Exp $
  */
 
 #include <sys/param.h>
@@ -310,7 +310,7 @@ icmp_input(m, hlen)
 			printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
 #endif
 		icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
-#ifdef MTUDISC
+#if 1
 		/*
 		 * MTU discovery:
 		 * If we got a needfrag and there is a host route to the
@@ -338,8 +338,8 @@ icmp_input(m, hlen)
 					mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu,
 							  1);
 				if (!mtu || mtu < 296) {
-					rt->rt_rmx.rmx_mtu =
-						rt->rt_ifp->if_mtu;
+					/* rt->rt_rmx.rmx_mtu =
+						rt->rt_ifp->if_mtu; */
 					rt->rt_rmx.rmx_locks |= RTV_MTU;
 				} else if (rt->rt_rmx.rmx_mtu > mtu) {
 					rt->rt_rmx.rmx_mtu = mtu;
@@ -349,7 +349,7 @@ icmp_input(m, hlen)
 				RTFREE(rt);
 		}
 
-#endif /* MTUDISC */
+#endif
 		ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
 		if (ctlfunc)
 			(*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
@@ -636,7 +636,7 @@ iptime()
 	return (htonl(t));
 }
 
-#ifdef MTUDISC
+#if 1
 /*
  * Return the next larger or smaller MTU plateau (table from RFC 1191)
  * given current value MTU.  If DIR is less than zero, a larger plateau
@@ -674,4 +674,4 @@ ip_next_mtu(mtu, dir)
 		}
 	}
 }
-#endif /* MTUDISC */
+#endif
diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index 4ad56744ef6..ca058b21705 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ip_output.c	8.3 (Berkeley) 1/21/94
- *	$Id: ip_output.c,v 1.24 1995/10/16 18:21:09 wollman Exp $
+ *	$Id: ip_output.c,v 1.25 1995/11/14 20:34:19 phk Exp $
  */
 
 #include <sys/param.h>
@@ -337,7 +337,7 @@ sendit:
 	 */
 	if (ip->ip_off & IP_DF) {
 		error = EMSGSIZE;
-#ifdef MTUDISC
+#if 1
 		/*
 		 * This case can happen if the user changed the MTU
 		 * of an interface after enabling IP on it.  Because
@@ -350,7 +350,7 @@ sendit:
 		    && (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
 			ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
 		}
-#endif /* MTUDISC */
+#endif
 		ipstat.ips_cantfrag++;
 		goto bad;
 	}
diff --git a/sys/netinet/ip_var.h b/sys/netinet/ip_var.h
index d22cf069325..15b5dbe48fc 100644
--- a/sys/netinet/ip_var.h
+++ b/sys/netinet/ip_var.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ip_var.h	8.2 (Berkeley) 1/9/95
- *	$Id: ip_var.h,v 1.15 1995/09/21 18:04:43 wollman Exp $
+ *	$Id: ip_var.h,v 1.16 1995/11/14 20:34:21 phk Exp $
  */
 
 #ifndef _NETINET_IP_VAR_H_
@@ -169,9 +169,7 @@ void	 ip_freemoptions __P((struct ip_moptions *));
 void	 ip_init __P((void));
 extern int	 (*ip_mforward) __P((struct ip *, struct ifnet *, struct mbuf *,
 			  struct ip_moptions *));
-#ifdef MTUDISC
 int	 ip_next_mtu __P((int, int));
-#endif /* MTUDISC */
 int	 ip_output __P((struct mbuf *,
 	    struct mbuf *, struct route *, int, struct ip_moptions *));
 void	 ip_slowtimo __P((void));
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
index f2387615df4..52dd4dfc375 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 1.15 1995/10/16 18:21:12 wollman Exp $
+ *	$Id: tcp_output.c,v 1.16 1995/11/03 22:08:08 olah Exp $
  */
 
 #include <sys/param.h>
@@ -653,13 +653,13 @@ send:
 	else
 #endif
     {
-#ifdef MTUDISC
+#if 1
 	struct rtentry *rt;
 #endif
 	((struct ip *)ti)->ip_len = m->m_pkthdr.len;
 	((struct ip *)ti)->ip_ttl = tp->t_inpcb->inp_ip.ip_ttl;	/* XXX */
 	((struct ip *)ti)->ip_tos = tp->t_inpcb->inp_ip.ip_tos;	/* XXX */
-#ifdef MTUDISC
+#if 1
 	/*
 	 * See if we should do MTU discovery.  We do it only if the following
 	 * are true:
@@ -672,7 +672,7 @@ send:
 	    && !(rt->rt_rmx.rmx_locks & RTV_MTU)) {
 		((struct ip *)ti)->ip_off |= IP_DF;
 	}
-#endif /* MTUDISC */
+#endif
 	error = ip_output(m, tp->t_inpcb->inp_options, &tp->t_inpcb->inp_route,
 	    so->so_options & SO_DONTROUTE, 0);
     }
@@ -682,7 +682,7 @@ out:
 			tcp_quench(tp->t_inpcb, 0);
 			return (0);
 		}
-#ifdef MTUDISC
+#if 1
 		if (error == EMSGSIZE) {
 			/*
 			 * ip_output() will have already fixed the route
@@ -693,7 +693,7 @@ out:
 			tcp_mtudisc(tp->t_inpcb, 0);
 			return 0;
 		}
-#endif /* MTUDISC */.
+#endif
 		if ((error == EHOSTUNREACH || error == ENETDOWN)
 		    && TCPS_HAVERCVDSYN(tp->t_state)) {
 			tp->t_softerror = error;
diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
index 2a2a5da8286..7520d1bd6a4 100644
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)tcp_subr.c	8.2 (Berkeley) 5/24/95
- *	$Id: tcp_subr.c,v 1.21 1995/11/09 20:23:05 phk Exp $
+ *	$Id: tcp_subr.c,v 1.22 1995/11/14 20:34:41 phk Exp $
  */
 
 #include <sys/param.h>
@@ -454,10 +454,10 @@ tcp_ctlinput(cmd, sa, ip)
 
 	if (cmd == PRC_QUENCH)
 		notify = tcp_quench;
-#ifdef MTUDISC
+#if 1
 	else if (cmd == PRC_MSGSIZE)
 		notify = tcp_mtudisc;
-#endif /* MTUDISC */
+#endif
 	else if (!PRC_IS_REDIRECT(cmd) &&
 		 ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0))
 		return;
@@ -484,7 +484,7 @@ tcp_quench(inp, errno)
 		tp->snd_cwnd = tp->t_maxseg;
 }
 
-#ifdef MTUDISC
+#if 1
 /*
  * When `need fragmentation' ICMP is received, update our idea of the MSS
  * based on the new value in the route.  Also nudge TCP to send something,
@@ -541,7 +541,7 @@ tcp_mtudisc(inp, errno)
 		tcp_output(tp);
 	}
 }
-#endif /* MTUDISC */
+#endif
 
 /*
  * Look-up the routing entry to the peer of this inpcb.  If no route
diff --git a/sys/netinet/tcp_timewait.c b/sys/netinet/tcp_timewait.c
index 2a2a5da8286..7520d1bd6a4 100644
--- a/sys/netinet/tcp_timewait.c
+++ b/sys/netinet/tcp_timewait.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)tcp_subr.c	8.2 (Berkeley) 5/24/95
- *	$Id: tcp_subr.c,v 1.21 1995/11/09 20:23:05 phk Exp $
+ *	$Id: tcp_subr.c,v 1.22 1995/11/14 20:34:41 phk Exp $
  */
 
 #include <sys/param.h>
@@ -454,10 +454,10 @@ tcp_ctlinput(cmd, sa, ip)
 
 	if (cmd == PRC_QUENCH)
 		notify = tcp_quench;
-#ifdef MTUDISC
+#if 1
 	else if (cmd == PRC_MSGSIZE)
 		notify = tcp_mtudisc;
-#endif /* MTUDISC */
+#endif
 	else if (!PRC_IS_REDIRECT(cmd) &&
 		 ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0))
 		return;
@@ -484,7 +484,7 @@ tcp_quench(inp, errno)
 		tp->snd_cwnd = tp->t_maxseg;
 }
 
-#ifdef MTUDISC
+#if 1
 /*
  * When `need fragmentation' ICMP is received, update our idea of the MSS
  * based on the new value in the route.  Also nudge TCP to send something,
@@ -541,7 +541,7 @@ tcp_mtudisc(inp, errno)
 		tcp_output(tp);
 	}
 }
-#endif /* MTUDISC */
+#endif
 
 /*
  * Look-up the routing entry to the peer of this inpcb.  If no route
diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
index 847931f2caa..706cf9fa520 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 1.22 1995/11/03 22:08:13 olah Exp $
+ * 	$Id: tcp_var.h,v 1.23 1995/11/14 20:34:50 phk Exp $
  */
 
 #ifndef _NETINET_TCP_VAR_H_
@@ -344,9 +344,7 @@ void	 tcp_init __P((void));
 void	 tcp_input __P((struct mbuf *, int));
 void	 tcp_mss __P((struct tcpcb *, int));
 int	 tcp_mssopt __P((struct tcpcb *));
-#ifdef MTUDISC
-void tcp_mtudisc __P((struct inpcb *, int));
-#endif /* MTUDISC */
+void	 tcp_mtudisc __P((struct inpcb *, int));
 struct tcpcb *
 	 tcp_newtcpcb __P((struct inpcb *));
 int	 tcp_output __P((struct tcpcb *));