ipv6: prepare fib6_locate() for exception table

fib6_locate() is used to find the fib6_node according to the passed in
prefix address key. It currently tries to find the fib6_node with the
exact match of the passed in key. However, when we move cached routes
into the exception table, fib6_locate() will fail to find the fib6_node
for it as the cached routes will be stored in the exception table under
the fib6_node with the longest prefix match of the cache's dst addr key.
This commit adds a new parameter to let the caller specify if it needs
exact match or longest prefix match.
Right now, all callers still does exact match when calling
fib6_locate(). It will be changed in later commit where exception table
is hooked up to store cached routes.

Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index 11a79ef..4497a1e 100644 (file)
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -357,7 +357,8 @@ struct fib6_node *fib6_lookup(struct fib6_node *root,
 
 struct fib6_node *fib6_locate(struct fib6_node *root,
                              const struct in6_addr *daddr, int dst_len,
-                             const struct in6_addr *saddr, int src_len);
+                             const struct in6_addr *saddr, int src_len,
+                             bool exact_match);
 
 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
                    void *arg);

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 837418f..3ccaf52 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2322,7 +2322,7 @@ static struct rt6_info *addrconf_get_prefix_route(const struct in6_addr *pfx,
                return NULL;
 
        read_lock_bh(&table->tb6_lock);
-       fn = fib6_locate(&table->tb6_root, pfx, plen, NULL, 0);
+       fn = fib6_locate(&table->tb6_root, pfx, plen, NULL, 0, true);
        if (!fn)
                goto out;
 

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 3afbe50..b3e4cf0 100644 (file)
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1343,14 +1343,21 @@ struct fib6_node *fib6_lookup(struct fib6_node *root, const struct in6_addr *dad
 /*
  *     Get node with specified destination prefix (and source prefix,
  *     if subtrees are used)
+ *     exact_match == true means we try to find fn with exact match of
+ *     the passed in prefix addr
+ *     exact_match == false means we try to find fn with longest prefix
+ *     match of the passed in prefix addr. This is useful for finding fn
+ *     for cached route as it will be stored in the exception table under
+ *     the node with longest prefix length.
  */
 
 
 static struct fib6_node *fib6_locate_1(struct fib6_node *root,
                                       const struct in6_addr *addr,
-                                      int plen, int offset)
+                                      int plen, int offset,
+                                      bool exact_match)
 {
-       struct fib6_node *fn;
+       struct fib6_node *fn, *prev = NULL;
 
        for (fn = root; fn ; ) {
                struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
@@ -1360,11 +1367,13 @@ static struct fib6_node *fib6_locate_1(struct fib6_node *root,
                 */
                if (plen < fn->fn_bit ||
                    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
-                       return NULL;
+                       goto out;
 
                if (plen == fn->fn_bit)
                        return fn;
 
+               prev = fn;
+
                /*
                 *      We have more bits to go
                 */
@@ -1373,24 +1382,31 @@ static struct fib6_node *fib6_locate_1(struct fib6_node *root,
                else
                        fn = fn->left;
        }
-       return NULL;
+out:
+       if (exact_match)
+               return NULL;
+       else
+               return prev;
 }
 
 struct fib6_node *fib6_locate(struct fib6_node *root,
                              const struct in6_addr *daddr, int dst_len,
-                             const struct in6_addr *saddr, int src_len)
+                             const struct in6_addr *saddr, int src_len,
+                             bool exact_match)
 {
        struct fib6_node *fn;
 
        fn = fib6_locate_1(root, daddr, dst_len,
-                          offsetof(struct rt6_info, rt6i_dst));
+                          offsetof(struct rt6_info, rt6i_dst),
+                          exact_match);
 
 #ifdef CONFIG_IPV6_SUBTREES
        if (src_len) {
                WARN_ON(saddr == NULL);
                if (fn && fn->subtree)
                        fn = fib6_locate_1(fn->subtree, saddr, src_len,
-                                          offsetof(struct rt6_info, rt6i_src));
+                                          offsetof(struct rt6_info, rt6i_src),
+                                          exact_match);
        }
 #endif
 

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index d2dd55f..855b4ce 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2800,7 +2800,8 @@ static int ip6_route_del(struct fib6_config *cfg,
 
        fn = fib6_locate(&table->tb6_root,
                         &cfg->fc_dst, cfg->fc_dst_len,
-                        &cfg->fc_src, cfg->fc_src_len);
+                        &cfg->fc_src, cfg->fc_src_len,
+                        true);
 
        if (fn) {
                for (rt = fn->leaf; rt; rt = rt->dst.rt6_next) {
@@ -3009,7 +3010,7 @@ static struct rt6_info *rt6_get_route_info(struct net *net,
                return NULL;
 
        read_lock_bh(&table->tb6_lock);
-       fn = fib6_locate(&table->tb6_root, prefix, prefixlen, NULL, 0);
+       fn = fib6_locate(&table->tb6_root, prefix, prefixlen, NULL, 0, true);
        if (!fn)
                goto out;