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authorDavid S. Miller <davem@davemloft.net>2011-01-31 16:16:50 -0800
committerDavid S. Miller <davem@davemloft.net>2011-01-31 16:16:50 -0800
commit0c838ff1ade71162775afffd9e5c6478a60bdca6 (patch)
tree81910cc5582f4862770307784c40c66aa3a44948 /net/ipv4/fib_semantics.c
parent5b4704419cbd0b7597a91c19f9e8e8b17c1af071 (diff)
downloadblackbird-op-linux-0c838ff1ade71162775afffd9e5c6478a60bdca6.tar.gz
blackbird-op-linux-0c838ff1ade71162775afffd9e5c6478a60bdca6.zip
ipv4: Consolidate all default route selection implementations.
Both fib_trie and fib_hash have a local implementation of fib_table_select_default(). This is completely unnecessary code duplication. Since we now remember the fib_table and the head of the fib alias list of the default route, we can implement one single generic version of this routine. Looking at the fib_hash implementation you may get the impression that it's possible for there to be multiple top-level routes in the table for the default route. The truth is, it isn't, the insert code will only allow one entry to exist in the zero prefix hash table, because all keys evaluate to zero and all keys in a hash table must be unique. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/fib_semantics.c')
-rw-r--r--net/ipv4/fib_semantics.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 1bf6fb906cfc..b15857d2b77e 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -1136,6 +1136,62 @@ int fib_sync_down_dev(struct net_device *dev, int force)
return ret;
}
+/* Must be invoked inside of an RCU protected region. */
+void fib_select_default(struct fib_result *res)
+{
+ struct fib_info *fi = NULL, *last_resort = NULL;
+ struct list_head *fa_head = res->fa_head;
+ struct fib_table *tb = res->table;
+ int order = -1, last_idx = -1;
+ struct fib_alias *fa;
+
+ list_for_each_entry_rcu(fa, fa_head, fa_list) {
+ struct fib_info *next_fi = fa->fa_info;
+
+ if (fa->fa_scope != res->scope ||
+ fa->fa_type != RTN_UNICAST)
+ continue;
+
+ if (next_fi->fib_priority > res->fi->fib_priority)
+ break;
+ if (!next_fi->fib_nh[0].nh_gw ||
+ next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
+ continue;
+
+ fib_alias_accessed(fa);
+
+ if (fi == NULL) {
+ if (next_fi != res->fi)
+ break;
+ } else if (!fib_detect_death(fi, order, &last_resort,
+ &last_idx, tb->tb_default)) {
+ fib_result_assign(res, fi);
+ tb->tb_default = order;
+ goto out;
+ }
+ fi = next_fi;
+ order++;
+ }
+
+ if (order <= 0 || fi == NULL) {
+ tb->tb_default = -1;
+ goto out;
+ }
+
+ if (!fib_detect_death(fi, order, &last_resort, &last_idx,
+ tb->tb_default)) {
+ fib_result_assign(res, fi);
+ tb->tb_default = order;
+ goto out;
+ }
+
+ if (last_idx >= 0)
+ fib_result_assign(res, last_resort);
+ tb->tb_default = last_idx;
+out:
+ rcu_read_unlock();
+}
+
#ifdef CONFIG_IP_ROUTE_MULTIPATH
/*
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