Re: [BUG] ipv6: all routes share same inetpeer

[Eric Dumazet <eric.dumazet@gmail.com>]

Le mardi 19 juillet 2011 à 10:37 -0700, David Miller a écrit :
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Tue, 19 Jul 2011 19:23:49 +0200
> 
> > Maybe you can find the bug before me ?
> 
> I think when we add the route we cow the metrics almost immediately.
> The daddr is, unfortunately, fully prefixed at that point.

Yes, we shall provide a second ip6_rt_copy() argument, with the
destination address.

I am testing :

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index ddef80f..2a6d70a 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -72,7 +72,7 @@
 #define RT6_TRACE(x...) do { ; } while (0)
 #endif
 
-static struct rt6_info * ip6_rt_copy(struct rt6_info *ort);
+static struct rt6_info * ip6_rt_copy(struct rt6_info *ort, const struct in6_addr *dest);
 static struct dst_entry	*ip6_dst_check(struct dst_entry *dst, u32 cookie);
 static unsigned int	 ip6_default_advmss(const struct dst_entry *dst);
 static unsigned int	 ip6_default_mtu(const struct dst_entry *dst);
@@ -699,7 +699,7 @@ static struct rt6_info *rt6_alloc_cow(struct rt6_info *ort, const struct in6_add
 	 *	Clone the route.
 	 */
 
-	rt = ip6_rt_copy(ort);
+	rt = ip6_rt_copy(ort, daddr);
 
 	if (rt) {
 		struct neighbour *neigh;
@@ -712,7 +712,6 @@ static struct rt6_info *rt6_alloc_cow(struct rt6_info *ort, const struct in6_add
 			ipv6_addr_copy(&rt->rt6i_gateway, daddr);
 		}
 
-		ipv6_addr_copy(&rt->rt6i_dst.addr, daddr);
 		rt->rt6i_dst.plen = 128;
 		rt->rt6i_flags |= RTF_CACHE;
 		rt->dst.flags |= DST_HOST;
@@ -761,9 +760,9 @@ static struct rt6_info *rt6_alloc_cow(struct rt6_info *ort, const struct in6_add
 
 static struct rt6_info *rt6_alloc_clone(struct rt6_info *ort, const struct in6_addr *daddr)
 {
-	struct rt6_info *rt = ip6_rt_copy(ort);
+	struct rt6_info *rt = ip6_rt_copy(ort, daddr);
+
 	if (rt) {
-		ipv6_addr_copy(&rt->rt6i_dst.addr, daddr);
 		rt->rt6i_dst.plen = 128;
 		rt->rt6i_flags |= RTF_CACHE;
 		rt->dst.flags |= DST_HOST;
@@ -1584,7 +1583,7 @@ void rt6_redirect(const struct in6_addr *dest, const struct in6_addr *src,
 	if (neigh == dst_get_neighbour(&rt->dst))
 		goto out;
 
-	nrt = ip6_rt_copy(rt);
+	nrt = ip6_rt_copy(rt, dest);
 	if (nrt == NULL)
 		goto out;
 
@@ -1592,7 +1591,6 @@ void rt6_redirect(const struct in6_addr *dest, const struct in6_addr *src,
 	if (on_link)
 		nrt->rt6i_flags &= ~RTF_GATEWAY;
 
-	ipv6_addr_copy(&nrt->rt6i_dst.addr, dest);
 	nrt->rt6i_dst.plen = 128;
 	nrt->dst.flags |= DST_HOST;
 
@@ -1730,7 +1728,7 @@ void rt6_pmtu_discovery(const struct in6_addr *daddr, const struct in6_addr *sad
  *	Misc support functions
  */
 
-static struct rt6_info * ip6_rt_copy(struct rt6_info *ort)
+static struct rt6_info * ip6_rt_copy(struct rt6_info *ort, const struct in6_addr *dest)
 {
 	struct net *net = dev_net(ort->rt6i_dev);
 	struct rt6_info *rt = ip6_dst_alloc(&net->ipv6.ip6_dst_ops,
@@ -1740,6 +1738,8 @@ static struct rt6_info * ip6_rt_copy(struct rt6_info *ort)
 		rt->dst.input = ort->dst.input;
 		rt->dst.output = ort->dst.output;
 
+		ipv6_addr_copy(&rt->rt6i_dst.addr, dest);
+		rt->rt6i_dst.plen = ort->rt6i_dst.plen;
 		dst_copy_metrics(&rt->dst, &ort->dst);
 		rt->dst.error = ort->dst.error;
 		rt->rt6i_idev = ort->rt6i_idev;
@@ -1752,7 +1752,6 @@ static struct rt6_info * ip6_rt_copy(struct rt6_info *ort)
 		rt->rt6i_flags = ort->rt6i_flags & ~RTF_EXPIRES;
 		rt->rt6i_metric = 0;
 
-		memcpy(&rt->rt6i_dst, &ort->rt6i_dst, sizeof(struct rt6key));
 #ifdef CONFIG_IPV6_SUBTREES
 		memcpy(&rt->rt6i_src, &ort->rt6i_src, sizeof(struct rt6key));
 #endif