[IPV6] FIB6RULE: Find source address during looking up route.
YOSHIFUJI Hideaki [Fri, 6 Apr 2007 18:45:39 +0000 (11:45 -0700)]
When looking up route for destination with rules with
source address restrictions, we may need to find a source
address for the traffic if not given.

Based on patch from Noriaki TAKAMIYA <takamiya@po.ntts.co.jp>.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/fib_rules.h
net/ipv6/fib6_rules.c

index f278ba7..87b606b 100644 (file)
@@ -5,10 +5,13 @@
 #include <linux/rtnetlink.h>
 
 /* rule is permanent, and cannot be deleted */
-#define FIB_RULE_PERMANENT     1
-#define FIB_RULE_INVERT                2
-#define FIB_RULE_UNRESOLVED    4
-#define FIB_RULE_DEV_DETACHED  8
+#define FIB_RULE_PERMANENT     0x00000001
+#define FIB_RULE_INVERT                0x00000002
+#define FIB_RULE_UNRESOLVED    0x00000004
+#define FIB_RULE_DEV_DETACHED  0x00000008
+
+/* try to find source address in routing lookups */
+#define FIB_RULE_FIND_SADDR    0x00010000
 
 struct fib_rule_hdr
 {
index dd9720e..fc3882c 100644 (file)
@@ -17,6 +17,7 @@
 
 #include <net/fib_rules.h>
 #include <net/ipv6.h>
+#include <net/addrconf.h>
 #include <net/ip6_route.h>
 #include <net/netlink.h>
 
@@ -95,8 +96,27 @@ static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
        if (table)
                rt = lookup(table, flp, flags);
 
-       if (rt != &ip6_null_entry)
+       if (rt != &ip6_null_entry) {
+               struct fib6_rule *r = (struct fib6_rule *)rule;
+
+               /*
+                * If we need to find a source address for this traffic,
+                * we check the result if it meets requirement of the rule.
+                */
+               if ((rule->flags & FIB_RULE_FIND_SADDR) &&
+                   r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
+                       struct in6_addr saddr;
+                       if (ipv6_get_saddr(&rt->u.dst, &flp->fl6_dst,
+                                          &saddr))
+                               goto again;
+                       if (!ipv6_prefix_equal(&saddr, &r->src.addr,
+                                              r->src.plen))
+                               goto again;
+                       ipv6_addr_copy(&flp->fl6_src, &saddr);
+               }
                goto out;
+       }
+again:
        dst_release(&rt->u.dst);
        rt = NULL;
        goto out;
@@ -117,9 +137,17 @@ static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
            !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen))
                return 0;
 
+       /*
+        * If FIB_RULE_FIND_SADDR is set and we do not have a
+        * source address for the traffic, we defer check for
+        * source address.
+        */
        if (r->src.plen) {
-               if (!(flags & RT6_LOOKUP_F_HAS_SADDR) ||
-                   !ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, r->src.plen))
+               if (flags & RT6_LOOKUP_F_HAS_SADDR) {
+                       if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr,
+                                              r->src.plen))
+                               return 0;
+               } else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
                        return 0;
        }