Date: Tue, 31 Oct 2006 10:58:07 +0100
From: Thomas Graf <tgraf@redhat.com>
Subject: [RHEL5 BZ209354]: [IPv6 MRT] irrelevant rules break ipv6 routing.

    [IPv6] rules: Use RT6_LOOKUP_F_HAS_SADDR and fix source based selectors
    
    Fixes rt6_lookup() to provide the source address in the flow
    and sets RT6_LOOKUP_F_HAS_SADDR whenever it is present in
    the flow.
    
    Avoids unnecessary prefix comparisons by checking for a prefix
    length first.
    
    Fixes the rule logic to not match packets if a source selector
    has been specified but no source address is available.
    
    Thanks to Kim Nordlund <kim.nordlund@nokia.com> for working
    on this patch with me.
    
    Signed-off-by: Thomas Graf <tgraf@suug.ch>
    Acked-by: Ville Nuorvala <vnuorval@tcs.hut.fi>
    Signed-off-by: David S. Miller <davem@davemloft.net>

Please ACK.

Index: linux-2.6.18.noarch/net/ipv6/fib6_rules.c
===================================================================
--- linux-2.6.18.noarch.orig/net/ipv6/fib6_rules.c	2006-10-30 16:19:59.000000000 +0100
+++ linux-2.6.18.noarch/net/ipv6/fib6_rules.c	2006-10-30 16:21:33.000000000 +0100
@@ -118,12 +118,15 @@
 {
 	struct fib6_rule *r = (struct fib6_rule *) rule;
 
-	if (!ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
+	if (r->dst.plen &&
+	    !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
 		return 0;
 
-	if ((flags & RT6_LOOKUP_F_HAS_SADDR) &&
-	    !ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, r->src.plen))
-		return 0;
+	if (r->src.plen) {
+		if (!(flags & RT6_LOOKUP_F_HAS_SADDR) ||
+		    !ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, r->src.plen))
+			return 0;
+	}
 
 	if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
 		return 0;
Index: linux-2.6.18.noarch/net/ipv6/route.c
===================================================================
--- linux-2.6.18.noarch.orig/net/ipv6/route.c	2006-10-30 16:19:59.000000000 +0100
+++ linux-2.6.18.noarch/net/ipv6/route.c	2006-10-30 16:21:33.000000000 +0100
@@ -527,13 +527,17 @@
 		.nl_u = {
 			.ip6_u = {
 				.daddr = *daddr,
-				/* TODO: saddr */
 			},
 		},
 	};
 	struct dst_entry *dst;
 	int flags = strict ? RT6_LOOKUP_F_IFACE : 0;
 
+	if (saddr) {
+		memcpy(&fl.fl6_src, saddr, sizeof(*saddr));
+		flags |= RT6_LOOKUP_F_HAS_SADDR;
+	}
+
 	dst = fib6_rule_lookup(&fl, flags, ip6_pol_route_lookup);
 	if (dst->error == 0)
 		return (struct rt6_info *) dst;
@@ -691,6 +695,7 @@
 void ip6_route_input(struct sk_buff *skb)
 {
 	struct ipv6hdr *iph = skb->nh.ipv6h;
+	int flags = RT6_LOOKUP_F_HAS_SADDR;
 	struct flowi fl = {
 		.iif = skb->dev->ifindex,
 		.nl_u = {
@@ -705,7 +710,9 @@
 		},
 		.proto = iph->nexthdr,
 	};
-	int flags = rt6_need_strict(&iph->daddr) ? RT6_LOOKUP_F_IFACE : 0;
+
+	if (rt6_need_strict(&iph->daddr))
+		flags |= RT6_LOOKUP_F_IFACE;
 
 	skb->dst = fib6_rule_lookup(&fl, flags, ip6_pol_route_input);
 }
@@ -788,6 +795,9 @@
 	if (rt6_need_strict(&fl->fl6_dst))
 		flags |= RT6_LOOKUP_F_IFACE;
 
+	if (!ipv6_addr_any(&fl->fl6_src))
+		flags |= RT6_LOOKUP_F_HAS_SADDR;
+
 	return fib6_rule_lookup(fl, flags, ip6_pol_route_output);
 }
 
@@ -1346,6 +1356,7 @@
 					   struct in6_addr *gateway,
 					   struct net_device *dev)
 {
+	int flags = RT6_LOOKUP_F_HAS_SADDR;
 	struct ip6rd_flowi rdfl = {
 		.fl = {
 			.oif = dev->ifindex,
@@ -1358,7 +1369,9 @@
 		},
 		.gateway = *gateway,
 	};
-	int flags = rt6_need_strict(dest) ? RT6_LOOKUP_F_IFACE : 0;
+
+	if (rt6_need_strict(dest))
+		flags |= RT6_LOOKUP_F_IFACE;
 
 	return (struct rt6_info *)fib6_rule_lookup((struct flowi *)&rdfl, flags, __ip6_route_redirect);
 }