[IPv4]: More fib_alias insertion fixes

[Julian Anastasov <ja@xxxxxx>]

        Hello,

        some fib alias fixes:

- modify fib_find_alias to stop before the desired alias, even
if reaching different TOS. If no alias is found we have to append
at end of fn_alias.

- properly prepend/append new alias with same prefix/tos/prio

- use list_for_each_entry_continue

Signed-off-by: Julian Anastasov <ja@xxxxxx>

diff -ur v2.6.9-rc2-bk10/linux/net/ipv4/fib_hash.c linux/net/ipv4/fib_hash.c
--- v2.6.9-rc2-bk10/linux/net/ipv4/fib_hash.c   2004-09-25 22:44:31.000000000 
+0300
+++ linux/net/ipv4/fib_hash.c   2004-09-25 22:45:06.580902744 +0300
@@ -431,24 +431,20 @@
        return NULL;
 }
 
-/* Return the first fib alias matching TOS with
- * priority less than or equal to PRIO.
- */
+/* Return the first fib alias below TOS and after PRIO thresholds */
 static struct fib_alias *fib_find_alias(struct fib_node *fn, u8 tos, u32 prio)
 {
        if (fn) {
                struct list_head *head = &fn->fn_alias;
-               struct fib_alias *fa, *prev_fa;
+               struct fib_alias *fa;
 
-               prev_fa = NULL;
                list_for_each_entry(fa, head, fa_list) {
-                       if (fa->fa_tos != tos)
+                       if (fa->fa_tos > tos)
                                continue;
-                       prev_fa = fa;
-                       if (prio <= fa->fa_info->fib_priority)
-                               break;
+                       if (fa->fa_info->fib_priority >= prio ||
+                           fa->fa_tos < tos)
+                               return fa;
                }
-               return prev_fa;
        }
        return NULL;
 }
@@ -461,6 +457,7 @@
        struct fib_node *new_f, *f;
        struct fib_alias *fa, *new_fa;
        struct fn_zone *fz;
+       struct list_head *ins_before = NULL;
        struct fib_info *fi;
        int z = r->rtm_dst_len;
        int type = r->rtm_type;
@@ -505,9 +502,12 @@
         * and we need to allocate a new one of those as well.
         */
 
-       if (fa &&
+       if (fa)
+               ins_before = &fa->fa_list;
+
+       if (fa && fa->fa_tos == tos &&
            fa->fa_info->fib_priority == fi->fib_priority) {
-               struct fib_alias *fa_orig;
+               struct list_head *fa_head;
 
                err = -EEXIST;
                if (n->nlmsg_flags & NLM_F_EXCL)
@@ -536,8 +536,9 @@
                 * uses the same scope, type, and nexthop
                 * information.
                 */
-               fa_orig = fa;
-               list_for_each_entry(fa, fa_orig->fa_list.prev, fa_list) {
+               fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
+               fa_head = &f->fn_alias;
+               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)
@@ -546,9 +547,9 @@
                            fa->fa_scope == r->rtm_scope &&
                            fa->fa_info == fi)
                                goto out;
+                       if (n->nlmsg_flags & NLM_F_APPEND)
+                               ins_before = fa->fa_list.next;
                }
-               if (!(n->nlmsg_flags & NLM_F_APPEND))
-                       fa = fa_orig;
        }
 
        err = -ENOENT;
@@ -585,8 +586,7 @@
        write_lock_bh(&fib_hash_lock);
        if (new_f)
                fib_insert_node(fz, new_f);
-       list_add(&new_fa->fa_list,
-                (fa ? &fa->fa_list : &f->fn_alias));
+       list_add_tail(&new_fa->fa_list, ins_before? : &f->fn_alias);
        write_unlock_bh(&fib_hash_lock);
 
        if (new_f)
@@ -637,8 +637,9 @@
                return -ESRCH;
 
        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);
+       fa_head = &f->fn_alias;
+       list_for_each_entry_continue(fa, fa_head, fa_list) {
                struct fib_info *fi = fa->fa_info;
 
                if (fa->fa_tos != tos)