ipv6: prepare fib6_remove_prefsrc() for exception table

After we move cached dst entries into the exception table under its
parent route, current fib6_remove_prefsrc() no longer can access them.
This commit makes fib6_remove_prefsrc() also go through all routes
in the exception table to remove the pref src.
This is a preparation patch in order to move all cached dst into the
exception table.

Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index dc5e709..f52ac57 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1264,6 +1264,12 @@ static int rt6_insert_exception(struct rt6_info *nrt,
        if (ort->rt6i_src.plen)
                src_key = &nrt->rt6i_src.addr;
 #endif
+
+       /* Update rt6i_prefsrc as it could be changed
+        * in rt6_remove_prefsrc()
+        */
+       nrt->rt6i_prefsrc = ort->rt6i_prefsrc;
+
        rt6_ex = __rt6_find_exception_spinlock(&bucket, &nrt->rt6i_dst.addr,
                                               src_key);
        if (rt6_ex)
@@ -1432,6 +1438,25 @@ static void rt6_update_exception_stamp_rt(struct rt6_info *rt)
        rcu_read_unlock();
 }
 
+static void rt6_exceptions_remove_prefsrc(struct rt6_info *rt)
+{
+       struct rt6_exception_bucket *bucket;
+       struct rt6_exception *rt6_ex;
+       int i;
+
+       bucket = rcu_dereference_protected(rt->rt6i_exception_bucket,
+                                       lockdep_is_held(&rt6_exception_lock));
+
+       if (bucket) {
+               for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {
+                       hlist_for_each_entry(rt6_ex, &bucket->chain, hlist) {
+                               rt6_ex->rt6i->rt6i_prefsrc.plen = 0;
+                       }
+                       bucket++;
+               }
+       }
+}
+
 struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
                               int oif, struct flowi6 *fl6, int flags)
 {
@@ -3159,8 +3184,12 @@ static int fib6_remove_prefsrc(struct rt6_info *rt, void *arg)
        if (((void *)rt->dst.dev == dev || !dev) &&
            rt != net->ipv6.ip6_null_entry &&
            ipv6_addr_equal(addr, &rt->rt6i_prefsrc.addr)) {
+               spin_lock_bh(&rt6_exception_lock);
                /* remove prefsrc entry */
                rt->rt6i_prefsrc.plen = 0;
+               /* need to update cache as well */
+               rt6_exceptions_remove_prefsrc(rt);
+               spin_unlock_bh(&rt6_exception_lock);
        }
        return 0;
 }