Re: [PATCH] IP: Increment INADDRERRORS if routing for a packet is not successful

[Eric Dumazet <eric.dumazet@gmail.com>]

Le mercredi 02 juin 2010 à 10:31 -0700, David Miller a écrit :
> Just in case people are really so clueless as to be unable to figure
> this out:
> 
> echo 1 >/sys/kernel/debug/tracing/events/skb/kfree_skb/enable
> ...do some stuff...
> cat /sys/kernel/debug/tracing/trace
> 
> You can even trace it using 'perf' by passing "skb:kfree_skb"
> as the event specifier.

Thanks !

Here is the patch I cooked to account for RP_FILTER errors in multicast
path.

I will complete it to also do the unicast part before official
submission.

Christoph, the official counter would be IPSTATS_MIB_INNOROUTES

ipSystemStatsInNoRoutes OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
           "The number of input IP datagrams discarded because no route
            could be found to transmit them to their destination.



diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 4f0ed45..f207289 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -284,7 +284,7 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
 	if (no_addr)
 		goto last_resort;
 	if (rpf == 1)
-		goto e_inval;
+		goto e_rpf;
 	fl.oif = dev->ifindex;
 
 	ret = 0;
@@ -299,7 +299,7 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
 
 last_resort:
 	if (rpf)
-		goto e_inval;
+		goto e_rpf;
 	*spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
 	*itag = 0;
 	return 0;
@@ -308,6 +308,8 @@ e_inval_res:
 	fib_res_put(&res);
 e_inval:
 	return -EINVAL;
+e_rpf:
+	return -ENETUNREACH;
 }
 
 static inline __be32 sk_extract_addr(struct sockaddr *addr)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 8495bce..8e9e2f9 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1851,6 +1851,7 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	__be32 spec_dst;
 	struct in_device *in_dev = in_dev_get(dev);
 	u32 itag = 0;
+	int err;
 
 	/* Primary sanity checks. */
 
@@ -1865,10 +1866,12 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 		if (!ipv4_is_local_multicast(daddr))
 			goto e_inval;
 		spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
-	} else if (fib_validate_source(saddr, 0, tos, 0,
-					dev, &spec_dst, &itag, 0) < 0)
-		goto e_inval;
-
+	} else {
+		err = fib_validate_source(saddr, 0, tos, 0, dev, &spec_dst,
+					  &itag, 0);
+		if (err < 0)
+			goto e_err;
+	}
 	rth = dst_alloc(&ipv4_dst_ops);
 	if (!rth)
 		goto e_nobufs;
@@ -1922,6 +1925,9 @@ e_nobufs:
 e_inval:
 	in_dev_put(in_dev);
 	return -EINVAL;
+e_err:
+	in_dev_put(in_dev);
+	return err;
 }