Hello.

On 05/29/2015 11:04 PM, Josh Hunt wrote:

I came across this problem while trying to use UDP encapsulation with IPv6. The
change below fixes that, but it was not immediately apparent if there are any
other protocols relying on this broken behavior. FWIW the behavior below now
matches IPv4.

Josh

   Need "Signed-off-by:" line insted of this.

v2: Actually sets nexthdr so we can use it ;)

   Normally goes after ---, not before.

---

UDP encapsulation is broken on IPv6 because it expects when it returns a 
negative
value that the packet will be resubmitted to the stack with the handler 
corresponding
to the return value. The check currently looks for return values > 0 and then 
resubmits.

This patch fixes that check and also moves the resubmit label to take advantage 
of
the return code identifying the next protocol we want to process.

Signed-off-by: Josh Hunt <joh...@akamai.com>
---
  net/ipv6/ip6_input.c |    7 ++++---
  1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index f2e464e..e16c289 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
[...]
@@ -246,9 +246,10 @@ resubmit:
                        goto discard;

                ret = ipprot->handler(skb);
-               if (ret > 0)
+               if (ret < 0) {
+                       nexthdr = -ret;
                        goto resubmit;
-               else if (ret == 0)
+               } else if (ret == 0)
                        IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);

The CodingStyle dictates that all branches must have {} if at least one has them.

[...]

WBR, Sergei

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