[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>

1 files changed, 35 insertions, 20 deletions

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index f2f47033f31f..cbccafde8238 100644
--- 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)