[IPV4] fib_trie: apply fixes from fib_hash

	Update fib_trie with some fib_hash fixes:
- check for duplicate alternative routes for prefix+tos+priority when
replacing route
- properly insert by matching tos together with priority
- fix alias walking to use list_for_each_entry_continue for insertion
and deletion when fa_head is not NULL
- copy state from fa to new_fa on replace (not a problem for now)
- additionally, avoid replacement without error if new route is same,
as Joonwoo Park suggests.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index f2f4703..cbccafd 100644 (file)
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1205,20 +1205,45 @@ static int fn_trie_insert(struct fib_table *tb, struct fib_config *cfg)
         * and we need to allocate a new one of those as well.
         */
 
-       if (fa && fa->fa_info->fib_priority == fi->fib_priority) {
-               struct fib_alias *fa_orig;
+       if (fa && fa->fa_tos == tos &&
+           fa->fa_info->fib_priority == fi->fib_priority) {
+               struct fib_alias *fa_first, *fa_match;
 
                err = -EEXIST;
                if (cfg->fc_nlflags & NLM_F_EXCL)
                        goto out;
 
+               /* We have 2 goals:
+                * 1. Find exact match for type, scope, fib_info to avoid
+                * duplicate routes
+                * 2. Find next 'fa' (or head), NLM_F_APPEND inserts before it
+                */
+               fa_match = NULL;
+               fa_first = fa;
+               fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
+               list_for_each_entry_continue(fa, fa_head, fa_list) {
+                       if (fa->fa_tos != tos)
+                               break;
+                       if (fa->fa_info->fib_priority != fi->fib_priority)
+                               break;
+                       if (fa->fa_type == cfg->fc_type &&
+                           fa->fa_scope == cfg->fc_scope &&
+                           fa->fa_info == fi) {
+                               fa_match = fa;
+                               break;
+                       }
+               }
+
                if (cfg->fc_nlflags & NLM_F_REPLACE) {
                        struct fib_info *fi_drop;
                        u8 state;
 
-                       if (fi->fib_treeref > 1)
+                       fa = fa_first;
+                       if (fa_match) {
+                               if (fa == fa_match)
+                                       err = 0;
                                goto out;
-
+                       }
                        err = -ENOBUFS;
                        new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
                        if (new_fa == NULL)
@@ -1230,7 +1255,7 @@ static int fn_trie_insert(struct fib_table *tb, struct fib_config *cfg)
                        new_fa->fa_type = cfg->fc_type;
                        new_fa->fa_scope = cfg->fc_scope;
                        state = fa->fa_state;
-                       new_fa->fa_state &= ~FA_S_ACCESSED;
+                       new_fa->fa_state = state & ~FA_S_ACCESSED;
 
                        list_replace_rcu(&fa->fa_list, &new_fa->fa_list);
                        alias_free_mem_rcu(fa);
@@ -1247,20 +1272,11 @@ static int fn_trie_insert(struct fib_table *tb, struct fib_config *cfg)
                 * uses the same scope, type, and nexthop
                 * information.
                 */
-               fa_orig = fa;
-               list_for_each_entry(fa, fa_orig->fa_list.prev, fa_list) {
-                       if (fa->fa_tos != tos)
-                               break;
-                       if (fa->fa_info->fib_priority != fi->fib_priority)
-                               break;
-                       if (fa->fa_type == cfg->fc_type &&
-                           fa->fa_scope == cfg->fc_scope &&
-                           fa->fa_info == fi)
-                               goto out;
-               }
+               if (fa_match)
+                       goto out;
 
                if (!(cfg->fc_nlflags & NLM_F_APPEND))
-                       fa = fa_orig;
+                       fa = fa_first;
        }
        err = -ENOENT;
        if (!(cfg->fc_nlflags & NLM_F_CREATE))
@@ -1600,9 +1616,8 @@ static int fn_trie_delete(struct fib_table *tb, struct fib_config *cfg)
        pr_debug("Deleting %08x/%d tos=%d t=%p\n", key, plen, tos, t);
 
        fa_to_delete = NULL;
-       fa_head = fa->fa_list.prev;
-
-       list_for_each_entry(fa, fa_head, fa_list) {
+       fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
+       list_for_each_entry_continue(fa, fa_head, fa_list) {
                struct fib_info *fi = fa->fa_info;
 
                if (fa->fa_tos != tos)