inet: add a redirect generation id in inetpeer

Now inetpeer is the place where we cache redirect information for ipv4
destinations, we must be able to invalidate informations when a route is
added/removed on host.

As inetpeer is not yet namespace aware, this patch adds a shared
redirect_genid, and a per inetpeer redirect_genid. This might be changed
later if inetpeer becomes ns aware.

Cache information for one inerpeer is valid as long as its
redirect_genid has the same value than global redirect_genid.

Reported-by: Arkadiusz Miśkiewicz <a.miskiewicz@gmail.com>
Tested-by: Arkadiusz Miśkiewicz <a.miskiewicz@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h
index 78c83e62218fbfff60506e4323f72343aed2b83a..e9ff3fc5e688615b6b4df99b0aef82af0621ab57 100644 (file)
--- a/include/net/inetpeer.h
+++ b/include/net/inetpeer.h
@@ -35,6 +35,7 @@ struct inet_peer {
 
        u32                     metrics[RTAX_MAX];
        u32                     rate_tokens;    /* rate limiting for ICMP */
+       int                     redirect_genid;
        unsigned long           rate_last;
        unsigned long           pmtu_expires;
        u32                     pmtu_orig;

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index fb47c8f0cd86f689e087bea4dfea8f0c87f3e0a9..5c2847247f51ba059c3685b2e644cc8fbe4334e1 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -131,6 +131,7 @@ static int ip_rt_mtu_expires __read_mostly  = 10 * 60 * HZ;
 static int ip_rt_min_pmtu __read_mostly                = 512 + 20 + 20;
 static int ip_rt_min_advmss __read_mostly      = 256;
 static int rt_chain_length_max __read_mostly   = 20;
+static int redirect_genid;
 
 /*
  *     Interface to generic destination cache.
@@ -837,6 +838,7 @@ static void rt_cache_invalidate(struct net *net)
 
        get_random_bytes(&shuffle, sizeof(shuffle));
        atomic_add(shuffle + 1U, &net->ipv4.rt_genid);
+       redirect_genid++;
 }
 
 /*
@@ -1391,8 +1393,10 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
 
                                peer = rt->peer;
                                if (peer) {
-                                       if (peer->redirect_learned.a4 != new_gw) {
+                                       if (peer->redirect_learned.a4 != new_gw ||
+                                           peer->redirect_genid != redirect_genid) {
                                                peer->redirect_learned.a4 = new_gw;
+                                               peer->redirect_genid = redirect_genid;
                                                atomic_inc(&__rt_peer_genid);
                                        }
                                        check_peer_redir(&rt->dst, peer);
@@ -1701,6 +1705,8 @@ static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
                if (peer) {
                        check_peer_pmtu(dst, peer);
 
+                       if (peer->redirect_genid != redirect_genid)
+                               peer->redirect_learned.a4 = 0;
                        if (peer->redirect_learned.a4 &&
                            peer->redirect_learned.a4 != rt->rt_gateway) {
                                if (check_peer_redir(dst, peer))
@@ -1857,6 +1863,8 @@ static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4,
                dst_init_metrics(&rt->dst, peer->metrics, false);
 
                check_peer_pmtu(&rt->dst, peer);
+               if (peer->redirect_genid != redirect_genid)
+                       peer->redirect_learned.a4 = 0;
                if (peer->redirect_learned.a4 &&
                    peer->redirect_learned.a4 != rt->rt_gateway) {
                        rt->rt_gateway = peer->redirect_learned.a4;