Re: [PATCH v3 2/2] Implement IPV6_UNICAST_IF socket option.

On 02/06/2012 05:11 PM, Erich E. Hoover wrote:

On Mon, Feb 6, 2012 at 2:13 PM, Brian Haley [off-list ref] wrote:

quoted

On 02/06/2012 12:57 PM, Erich E. Hoover wrote:

quoted

...
+     int                     outif_index;

...
Nitpick: is ucast_oif a better name?

I templated off of the IPv4 code (example: mc_index), but I do think
that that is a better name.  Should I call the IPv4 version
"ucast_index" or have the same name for both IPv4 and IPv6?

If it was me I'd call it uc_index for IPv4, to mimic mc_ifindex.

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diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 01d46bf..18f144e 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c

@@ -551,6 +551,9 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
              return;
      np = inet6_sk(sk);

+     if (!fl6.flowi6_oif)
+             fl6.flowi6_oif = ipv6_default_ifindex(sk);
+
      if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
              fl6.flowi6_oif = np->mcast_oif;

This snippet shows (and rawv6_sendmsg() has the same problem), that
IPV6_UNICAST_IF can also affect multicast packets.  And I think we always want
SO_BINDTODEVICE to override them all.  Perhaps these checks should be:
...

I'll double check all of these tonight, but a cursory look seems to
indicate that the multicast check is the right place to put this for
all the files.  I'm sorry about that, I clearly didn't consider
interfering with multicast.

It's probably important to keep the precedence the same as before:

	SO_BINDTODEVICE
	IPV6_PKTINFO
	IPV6_*CAST_IF

It looks like your IPv4 changes have the same problem.

-Brian