sctp: fix sctp to work with ipv6 source address routing

In the below test case, using the source address routing, sctp can not work. Node-A 1)ifconfig eth0 inet6 add 2001:1::1/64 2)ip -6 rule add from 2001:1::1 table 100 pref 100 3)ip -6 route add 2001:2::1 dev eth0 table 100 4)sctp_darn -H 2001:1::1 -P 250 -l & Node-B 1)ifconfig eth0 inet6 add 2001:2::1/64 2)ip -6 rule add from 2001:2::1 table 100 pref 100 3)ip -6 route add 2001:1::1 dev eth0 table 100 4)sctp_darn -H 2001:2::1 -P 250 -h 2001:1::1 -p 250 -s root cause: Node-A and Node-B use the source address routing, and at begining, source address will be NULL,sctp will search the routing table by the destination address, because using the source address routing table, and the result dst_entry will be NULL. solution: walk through the bind address list to get the source address and then lookup the routing table again to get the correct dst_entry. Signed-off-by: Weixing Shi <Weixing.Shi@windriver.com> Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com> Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: fix sctp to work with ipv6 source address routing
In the below test case, using the source address routing, sctp can not work. Node-A 1)ifconfig eth0 inet6 add 2001:1::1/64 2)ip -6 rule add from 2001:1::1 table 100 pref 100 3)ip -6 route add 2001:2::1 dev eth0 table 100 4)sctp_darn -H 2001:1::1 -P 250 -l & Node-B 1)ifconfig eth0 inet6 add 2001:2::1/64 2)ip -6 rule add from 2001:2::1 table 100 pref 100 3)ip -6 route add 2001:1::1 dev eth0 table 100 4)sctp_darn -H 2001:2::1 -P 250 -h 2001:1::1 -p 250 -s root cause: Node-A and Node-B use the source address routing, and at begining, source address will be NULL,sctp will search the routing table by the destination address, because using the source address routing table, and the result dst_entry will be NULL. solution: walk through the bind address list to get the source address and then lookup the routing table again to get the correct dst_entry. Signed-off-by: Weixing Shi <Weixing.Shi@windriver.com> Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com> Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Weixing Shi · David S. Miller
1 parent 66e6961c8e
Showing 1 changed file with 43 additions and 1 deletions Side-by-side Diff
net/sctp/ipv6.c
@@ -80,6 +80,9 @@
  
 #include <asm/uaccess.h>
  
+static inline int sctp_v6_addr_match_len(union sctp_addr *s1,
+					 union sctp_addr *s2);
+
 /* Event handler for inet6 address addition/deletion events.
  * The sctp_local_addr_list needs to be protocted by a spin lock since
  * multiple notifiers (say IPv4 and IPv6) may be running at the same
  
@@ -244,8 +247,14 @@
 					 union sctp_addr *daddr,
 					 union sctp_addr *saddr)
 {
-	struct dst_entry *dst;
+	struct dst_entry *dst = NULL;
 	struct flowi6 fl6;
+	struct sctp_bind_addr *bp;
+	struct sctp_sockaddr_entry *laddr;
+	union sctp_addr *baddr = NULL;
+	__u8 matchlen = 0;
+	__u8 bmatchlen;
+	sctp_scope_t scope;
  
 	memset(&fl6, 0, sizeof(fl6));
 	ipv6_addr_copy(&fl6.daddr, &daddr->v6.sin6_addr);
@@ -261,6 +270,39 @@
 	}
  
 	dst = ip6_route_output(&init_net, NULL, &fl6);
+	if (!asoc || saddr)
+		goto out;
+
+	if (dst->error) {
+		dst_release(dst);
+		dst = NULL;
+		bp = &asoc->base.bind_addr;
+		scope = sctp_scope(daddr);
+		/* Walk through the bind address list and try to get a dst that
+		 * matches a bind address as the source address.
+		 */
+		rcu_read_lock();
+		list_for_each_entry_rcu(laddr, &bp->address_list, list) {
+			if (!laddr->valid)
+				continue;
+			if ((laddr->state == SCTP_ADDR_SRC) &&
+			    (laddr->a.sa.sa_family == AF_INET6) &&
+			    (scope <= sctp_scope(&laddr->a))) {
+				bmatchlen = sctp_v6_addr_match_len(daddr,
+								   &laddr->a);
+				if (!baddr || (matchlen < bmatchlen)) {
+					baddr = &laddr->a;
+					matchlen = bmatchlen;
+				}
+			}
+		}
+		rcu_read_unlock();
+		if (baddr) {
+			ipv6_addr_copy(&fl6.saddr, &baddr->v6.sin6_addr);
+			dst = ip6_route_output(&init_net, NULL, &fl6);
+		}
+	}
+out:
 	if (!dst->error) {
 		struct rt6_info *rt;
 		rt = (struct rt6_info *)dst;
...	...	@@ -80,6 +80,9 @@
80	80
81	81	#include <asm/uaccess.h>
82	82
	83	+static inline int sctp_v6_addr_match_len(union sctp_addr *s1,
	84	+ union sctp_addr *s2);
	85	+
83	86	/* Event handler for inet6 address addition/deletion events.
84	87	* The sctp_local_addr_list needs to be protocted by a spin lock since
85	88	* multiple notifiers (say IPv4 and IPv6) may be running at the same
86	89
...	...	@@ -244,8 +247,14 @@
244	247	union sctp_addr *daddr,
245	248	union sctp_addr *saddr)
246	249	{
247		- struct dst_entry *dst;
	250	+ struct dst_entry *dst = NULL;
248	251	struct flowi6 fl6;
	252	+ struct sctp_bind_addr *bp;
	253	+ struct sctp_sockaddr_entry *laddr;
	254	+ union sctp_addr *baddr = NULL;
	255	+ __u8 matchlen = 0;
	256	+ __u8 bmatchlen;
	257	+ sctp_scope_t scope;
249	258
250	259	memset(&fl6, 0, sizeof(fl6));
251	260	ipv6_addr_copy(&fl6.daddr, &daddr->v6.sin6_addr);
...	...	@@ -261,6 +270,39 @@
261	270	}
262	271
263	272	dst = ip6_route_output(&init_net, NULL, &fl6);
	273	+ if (!asoc \|\| saddr)
	274	+ goto out;
	275	+
	276	+ if (dst->error) {
	277	+ dst_release(dst);
	278	+ dst = NULL;
	279	+ bp = &asoc->base.bind_addr;
	280	+ scope = sctp_scope(daddr);
	281	+ /* Walk through the bind address list and try to get a dst that
	282	+ * matches a bind address as the source address.
	283	+ */
	284	+ rcu_read_lock();
	285	+ list_for_each_entry_rcu(laddr, &bp->address_list, list) {
	286	+ if (!laddr->valid)
	287	+ continue;
	288	+ if ((laddr->state == SCTP_ADDR_SRC) &&
	289	+ (laddr->a.sa.sa_family == AF_INET6) &&
	290	+ (scope <= sctp_scope(&laddr->a))) {
	291	+ bmatchlen = sctp_v6_addr_match_len(daddr,
	292	+ &laddr->a);
	293	+ if (!baddr \|\| (matchlen < bmatchlen)) {
	294	+ baddr = &laddr->a;
	295	+ matchlen = bmatchlen;
	296	+ }
	297	+ }
	298	+ }
	299	+ rcu_read_unlock();
	300	+ if (baddr) {
	301	+ ipv6_addr_copy(&fl6.saddr, &baddr->v6.sin6_addr);
	302	+ dst = ip6_route_output(&init_net, NULL, &fl6);
	303	+ }
	304	+ }
	305	+out:
264	306	if (!dst->error) {
265	307	struct rt6_info *rt;
266	308	rt = (struct rt6_info *)dst;