Re: [PATCH] [IPv4] Reply net unreachable ICMP message

Hello, Jarek,

I am sorry, but I think I am nor sure I underatand exactly what you mean when
you say:
"It overrides err codes from fib_lookup, where such decisions should be made."

What is incorrect here ?

There are two lines added in this patch;

IP_INC_STATS_BH(IPSTATS_MIB_INNOROUTES);
and err = -ENETUNREACH;

The first one is, regardless to say, not relevant to err codes.

The second, err = -ENETUNREACH, is from: ip_route_input_slow().
(net/ipv4/route.c).

Assigning values to err is done more than once in this method;
for example,
e_hostunreach:
	err = -EHOSTUNREACH;

e_inval:
	err = -EINVAL;

e_nobufs:
	err = -ENOBUFS;

So I don't think anything is incorrect here.


Regards,
Rami Rosen

	


On Dec 6, 2007 9:49 AM, Jarek Poplawski [off-list ref] wrote:

On 06-12-2007 07:31, Mitsuru Chinen wrote:

quoted

IPv4 stack doesn't reply any ICMP destination unreachable message
with net unreachable code when IP detagrams are being discarded
because of no route could be found in the forwarding path.
Incidentally, IPv6 stack replies such ICMPv6 message in the similar
situation.

Signed-off-by: Mitsuru Chinen <redacted>
---
 net/ipv4/route.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 6714bbc..ba85ec9 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c

@@ -1375,6 +1375,7 @@ static int ip_error(struct sk_buff *skb)
                      break;
              case ENETUNREACH:
                      code = ICMP_NET_UNREACH;
+                     IP_INC_STATS_BH(IPSTATS_MIB_INNOROUTES);
                      break;
              case EACCES:
                      code = ICMP_PKT_FILTERED;

@@ -2004,6 +2005,7 @@ no_route:
      RT_CACHE_STAT_INC(in_no_route);
      spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
      res.type = RTN_UNREACHABLE;
+     err = -ENETUNREACH;
      goto local_input;

      /*

This patch seems to be wrong. It overrides err codes from
fib_lookup, where such decisions should be made.

Regards,
Jarek P.

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