introduce sysctl net.inet6.ip6.multicast_mtudisc (for multicast routers).

deraadt ok.  manpage nit by jmc.

6 files changed, 33 insertions, 21 deletions

diff --git a/lib/libc/gen/sysctl.3 b/lib/libc/gen/sysctl.3
index fdb9ad92689..34779660330 100644
--- a/lib/libc/gen/sysctl.3
+++ b/lib/libc/gen/sysctl.3
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: sysctl.3,v 1.161 2006/10/16 04:55:21 mcbride Exp $
+.\"	$OpenBSD: sysctl.3,v 1.162 2006/11/21 05:37:32 itojun Exp $
 .\"
 .\" Copyright (c) 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -1556,6 +1556,7 @@ The currently defined protocols and names are:
 .It ip6	maxfragpackets	integer	yes
 .It ip6	maxfrags	integer	yes
 .It ip6	mforwarding	integer	yes
+.It ip6	multicast_mtudisc	integer	yes
 .It ip6	multipath	integer	yes
 .It ip6	redirect	integer	yes
 .It ip6	rr_prune	integer	yes
@@ -1740,6 +1741,13 @@ The flag is provided basically for avoiding possible DoS attacks.
 If set to 1, then multicast forwarding is enabled for the host.
 The default is 0.
 .Pp
+.It Li ip6.multicast_mtudisc
+This variable controls generation of ICMPv6 Too Big messages
+when the machine is performing as an IPv6 multicast router.
+If set to 1, an ICMPv6 Too Big message will be generated for multicast packets
+which were too big to be forwarded.
+If set to 0, the ICMPv6 Too Big message will be suppressed.
+.Pp
 .It Li ip6.multipath
 This variable enables multipath routing for IPv6 addresses.
 If set to 0, only the first route selected will be used for a given
diff --git a/sbin/sysctl/sysctl.8 b/sbin/sysctl/sysctl.8
index 6d35d7cb9a9..b1f7eccad10 100644
--- a/sbin/sysctl/sysctl.8
+++ b/sbin/sysctl/sysctl.8
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: sysctl.8,v 1.134 2006/10/16 08:24:14 jmc Exp $
+.\"	$OpenBSD: sysctl.8,v 1.135 2006/11/21 05:37:32 itojun Exp $
 .\"	$NetBSD: sysctl.8,v 1.4 1995/09/30 07:12:49 thorpej Exp $
 .\"
 .\" Copyright (c) 1993
@@ -305,6 +305,7 @@ not all of the variables are relevant to all architectures.
 .It net.inet6.ip6.maxfrags	integer	yes
 .It net.inet6.ip6.mforwarding	integer	yes
 .It net.inet6.ip6.multipath	integer	yes
+.It net.inet6.ip6.multicast_mtudisc	integer	yes
 .It net.inet6.icmp6.rediraccept	integer	yes
 .It net.inet6.icmp6.redirtimeout	integer	yes
 .It net.inet6.icmp6.nd6_prune	integer	yes
diff --git a/sys/netinet6/in6.h b/sys/netinet6/in6.h
index d965b80af50..a723cf2e143 100644
--- a/sys/netinet6/in6.h
+++ b/sys/netinet6/in6.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6.h,v 1.41 2006/11/17 02:00:21 itojun Exp $	*/
+/*	$OpenBSD: in6.h,v 1.42 2006/11/21 05:37:32 itojun Exp $	*/
 /*	$KAME: in6.h,v 1.83 2001/03/29 02:55:07 jinmei Exp $	*/
 
 /*
@@ -565,7 +565,8 @@ struct in6_pktinfo {
 #define IPV6CTL_MAXFRAGS	41	/* max fragments */
 #define IPV6CTL_MFORWARDING	42
 #define IPV6CTL_MULTIPATH	43
-#define IPV6CTL_MAXID		44
+#define IPV6CTL_MCAST_PMTU	44	/* path MTU discovery for multicast */
+#define IPV6CTL_MAXID		45
 /* New entries should be added here from current IPV6CTL_MAXID value. */
 /* to define items, should talk with KAME guys first, for *BSD compatibility */
 
@@ -614,6 +615,7 @@ struct in6_pktinfo {
 	{ "maxfrags", CTLTYPE_INT }, \
 	{ "mforwarding", CTLTYPE_INT }, \
 	{ "multipath", CTLTYPE_INT }, \
+	{ "multicast_mtudisc", CTLTYPE_INT }, \
 }
 
 #define IPV6CTL_VARS { \
@@ -661,6 +663,7 @@ struct in6_pktinfo {
 	&ip6_maxfrags, \
 	&ip6_mforwarding, \
 	&ip6_multipath, \
+	&ip6_mcast_pmtu, \
 }
 
 #endif /* __BSD_VISIBLE */
diff --git a/sys/netinet6/in6_proto.c b/sys/netinet6/in6_proto.c
index 1a881003002..bb0732d367c 100644
--- a/sys/netinet6/in6_proto.c
+++ b/sys/netinet6/in6_proto.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6_proto.c,v 1.50 2006/06/18 11:47:46 pascoe Exp $	*/
+/*	$OpenBSD: in6_proto.c,v 1.51 2006/11/21 05:37:32 itojun Exp $	*/
 /*	$KAME: in6_proto.c,v 1.66 2000/10/10 15:35:47 itojun Exp $	*/
 
 /*
@@ -269,6 +269,7 @@ int	ip6_auto_flowlabel = 1;
 int	ip6_use_deprecated = 1;	/* allow deprecated addr (RFC2462 5.5.4) */
 int	ip6_rr_prune = 5;	/* router renumbering prefix
 				 * walk list every 5 sec.    */
+int	ip6_mcast_pmtu = 0;	/* enable pMTU discovery for multicast? */
 const int ip6_v6only = 1;
 u_int32_t ip6_id = 0UL;
 int	ip6_keepfaith = 0;
diff --git a/sys/netinet6/ip6_mroute.c b/sys/netinet6/ip6_mroute.c
index 3585cc24a3d..81f049e213b 100644
--- a/sys/netinet6/ip6_mroute.c
+++ b/sys/netinet6/ip6_mroute.c
@@ -106,9 +106,7 @@
 
 #include <netinet/in.h>
 #include <netinet/in_var.h>
-#ifdef MULTICAST_PMTUD
 #include <netinet/icmp6.h>
-#endif
 
 #include <netinet/ip6.h>
 #include <netinet6/ip6_var.h>
@@ -1595,21 +1593,21 @@ phyint_send(ip6, mifp, m)
 			    mifp - mif6table, error);
 #endif
 	} else {
-#ifdef MULTICAST_PMTUD
-		icmp6_error(mb_copy, ICMP6_PACKET_TOO_BIG, 0, linkmtu);
-#else
+		if (ip6_mcast_pmtu)
+			icmp6_error(mb_copy, ICMP6_PACKET_TOO_BIG, 0, linkmtu);
+		else {
 #ifdef MRT6DEBUG
-		if (mrt6debug & DEBUG_XMIT)
-			log(LOG_DEBUG,
-			    "phyint_send: packet too big on %s o %s g %s"
-			    " size %d(discarded)\n",
-			    ifp->if_xname,
-			    ip6_sprintf(&ip6->ip6_src),
-			    ip6_sprintf(&ip6->ip6_dst),
-			    mb_copy->m_pkthdr.len);
+			if (mrt6debug & DEBUG_XMIT)
+				log(LOG_DEBUG,
+				    "phyint_send: packet too big on %s o %s g %s"
+				    " size %d(discarded)\n",
+				    ifp->if_xname,
+				    ip6_sprintf(&ip6->ip6_src),
+				    ip6_sprintf(&ip6->ip6_dst),
+				    mb_copy->m_pkthdr.len);
 #endif /* MRT6DEBUG */
-		m_freem(mb_copy); /* simply discard the packet */
-#endif
+			m_freem(mb_copy); /* simply discard the packet */
+		}
 	}
 
 	splx(s);
diff --git a/sys/netinet6/ip6_var.h b/sys/netinet6/ip6_var.h
index a4268785a62..2f4c92181c5 100644
--- a/sys/netinet6/ip6_var.h
+++ b/sys/netinet6/ip6_var.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip6_var.h,v 1.28 2006/07/06 02:56:58 brad Exp $	*/
+/*	$OpenBSD: ip6_var.h,v 1.29 2006/11/21 05:37:32 itojun Exp $	*/
 /*	$KAME: ip6_var.h,v 1.33 2000/06/11 14:59:20 jinmei Exp $	*/
 
 /*
@@ -213,6 +213,7 @@ extern int	ip6_forward_srcrt;	/* forward src-routed? */
 extern int	ip6_use_deprecated;	/* allow deprecated addr as source */
 extern int	ip6_rr_prune;		/* router renumbering prefix
 					 * walk list every 5 sec.    */
+extern int	ip6_mcast_pmtu;		/* path MTU discovery for multicast */
 extern const int	ip6_v6only;
 
 extern struct socket *ip6_mrouter; 	/* multicast routing daemon */