[IPV6]: Multiple Routing Tables

Adds the framework to support multiple IPv6 routing tables.
Currently all automatically generated routes are put into the
same table. This could be changed at a later point after
considering the produced locking overhead.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 140 insertions, 4 deletions

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 764221220afd..fcd7da830aca 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -26,6 +26,7 @@
 #include <linux/netdevice.h>
 #include <linux/in6.h>
 #include <linux/init.h>
+#include <linux/list.h>
 
 #ifdef  CONFIG_PROC_FS
 #include <linux/proc_fs.h>
@@ -147,6 +148,126 @@ static __inline__ void rt6_release(struct rt6_info *rt)
                 dst_free(&rt->u.dst);
 }
 
+static struct fib6_table fib6_main_tbl = {
+        .tb6_id         = RT6_TABLE_MAIN,
+        .tb6_lock       = RW_LOCK_UNLOCKED,
+        .tb6_root       = {
+                .leaf           = &ip6_null_entry,
+                .fn_flags       = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO,
+        },
+};
+
+#ifdef CONFIG_IPV6_MULTIPLE_TABLES
+
+#define FIB_TABLE_HASHSZ 256
+static struct hlist_head fib_table_hash[FIB_TABLE_HASHSZ];
+
+static struct fib6_table *fib6_alloc_table(u32 id)
+{
+        struct fib6_table *table;
+
+        table = kzalloc(sizeof(*table), GFP_ATOMIC);
+        if (table != NULL) {
+                table->tb6_id = id;
+                table->tb6_lock = RW_LOCK_UNLOCKED;
+                table->tb6_root.leaf = &ip6_null_entry;
+                table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
+        }
+
+        return table;
+}
+
+static void fib6_link_table(struct fib6_table *tb)
+{
+        unsigned int h;
+
+        h = tb->tb6_id & (FIB_TABLE_HASHSZ - 1);
+
+        /*
+         * No protection necessary, this is the only list mutatation
+         * operation, tables never disappear once they exist.
+         */
+        hlist_add_head_rcu(&tb->tb6_hlist, &fib_table_hash[h]);
+}
+
+struct fib6_table *fib6_new_table(u32 id)
+{
+        struct fib6_table *tb;
+
+        if (id == 0)
+                id = RT6_TABLE_MAIN;
+        tb = fib6_get_table(id);
+        if (tb)
+                return tb;
+
+        tb = fib6_alloc_table(id);
+        if (tb != NULL)
+                fib6_link_table(tb);
+
+        return tb;
+}
+
+struct fib6_table *fib6_get_table(u32 id)
+{
+        struct fib6_table *tb;
+        struct hlist_node *node;
+        unsigned int h;
+
+        if (id == 0)
+                id = RT6_TABLE_MAIN;
+        h = id & (FIB_TABLE_HASHSZ - 1);
+        rcu_read_lock();
+        hlist_for_each_entry_rcu(tb, node, &fib_table_hash[h], tb6_hlist) {
+                if (tb->tb6_id == id) {
+                        rcu_read_unlock();
+                        return tb;
+                }
+        }
+        rcu_read_unlock();
+
+        return NULL;
+}
+
+struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags,
+                                   pol_lookup_t lookup)
+{
+        /*
+         * TODO: Add rule lookup
+         */
+        struct fib6_table *table = fib6_get_table(RT6_TABLE_MAIN);
+
+        return (struct dst_entry *) lookup(table, fl, flags);
+}
+
+static void __init fib6_tables_init(void)
+{
+        fib6_link_table(&fib6_main_tbl);
+}
+
+#else
+
+struct fib6_table *fib6_new_table(u32 id)
+{
+        return fib6_get_table(id);
+}
+
+struct fib6_table *fib6_get_table(u32 id)
+{
+        return &fib6_main_tbl;
+}
+
+struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags,
+                                   pol_lookup_t lookup)
+{
+        return (struct dst_entry *) lookup(&fib6_main_tbl, fl, flags);
+}
+
+static void __init fib6_tables_init(void)
+{
+}
+
+#endif
+
 
 /*
  *      Routing Table
@@ -1064,6 +1185,22 @@ void fib6_clean_tree(struct fib6_node *root,
         fib6_walk(&c.w);
 }
 
+void fib6_clean_all(int (*func)(struct rt6_info *, void *arg),
+                    int prune, void *arg)
+{
+        int i;
+        struct fib6_table *table;
+
+        for (i = FIB6_TABLE_MIN; i <= FIB6_TABLE_MAX; i++) {
+                table = fib6_get_table(i);
+                if (table != NULL) {
+                        write_lock_bh(&table->tb6_lock);
+                        fib6_clean_tree(&table->tb6_root, func, prune, arg);
+                        write_unlock_bh(&table->tb6_lock);
+                }
+        }
+}
+
 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
 {
         if (rt->rt6i_flags & RTF_CACHE) {
@@ -1142,11 +1279,8 @@ void fib6_run_gc(unsigned long dummy)
         }
         gc_args.more = 0;
 
-
-        write_lock_bh(&rt6_lock);
         ndisc_dst_gc(&gc_args.more);
-        fib6_clean_tree(&ip6_routing_table, fib6_age, 0, NULL);
-        write_unlock_bh(&rt6_lock);
+        fib6_clean_all(fib6_age, 0, NULL);
 
         if (gc_args.more)
                 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
@@ -1165,6 +1299,8 @@ void __init fib6_init(void)
                                            NULL, NULL);
         if (!fib6_node_kmem)
                 panic("cannot create fib6_nodes cache");
+
+        fib6_tables_init();
 }
 
 void fib6_gc_cleanup(void)