ipv4: Cache ip_error() routes even when not forwarding.

And account for the fact that, when we are not forwarding, we should
bump statistic counters rather than emit an ICMP response.

RP-filter rejected lookups are still not cached.

Since -EHOSTUNREACH and -ENETUNREACH can now no longer be seen in
ip_rcv_finish(), remove those checks.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 11 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 846961c6cbe..81533e3a23d 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1609,12 +1609,28 @@ void ip_rt_send_redirect(struct sk_buff *skb)
 
 static int ip_error(struct sk_buff *skb)
 {
+        struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
         struct rtable *rt = skb_rtable(skb);
         struct inet_peer *peer;
         unsigned long now;
+        struct net *net;
         bool send;
         int code;
 
+        net = dev_net(rt->dst.dev);
+        if (!IN_DEV_FORWARD(in_dev)) {
+                switch (rt->dst.error) {
+                case EHOSTUNREACH:
+                        IP_INC_STATS_BH(net, IPSTATS_MIB_INADDRERRORS);
+                        break;
+
+                case ENETUNREACH:
+                        IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
+                        break;
+                }
+                goto out;
+        }
+
         switch (rt->dst.error) {
         case EINVAL:
         default:
@@ -1624,8 +1640,7 @@ static int ip_error(struct sk_buff *skb)
                 break;
         case ENETUNREACH:
                 code = ICMP_NET_UNREACH;
-                IP_INC_STATS_BH(dev_net(rt->dst.dev),
-                                IPSTATS_MIB_INNOROUTES);
+                IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
                 break;
         case EACCES:
                 code = ICMP_PKT_FILTERED;
@@ -2255,11 +2270,8 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
         fl4.daddr = daddr;
         fl4.saddr = saddr;
         err = fib_lookup(net, &fl4, &res);
-        if (err != 0) {
-                if (!IN_DEV_FORWARD(in_dev))
-                        goto e_hostunreach;
+        if (err != 0)
                 goto no_route;
-        }
 
         RT_CACHE_STAT_INC(in_slow_tot);
 
@@ -2279,7 +2291,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
         }
 
         if (!IN_DEV_FORWARD(in_dev))
-                goto e_hostunreach;
+                goto no_route;
         if (res.type != RTN_UNICAST)
                 goto martian_destination;
 
@@ -2367,10 +2379,6 @@ martian_destination:
                                      &daddr, &saddr, dev->name);
 #endif
 
-e_hostunreach:
-        err = -EHOSTUNREACH;
-        goto out;
-
 e_inval:
         err = -EINVAL;
         goto out;