Re: [PATCH] link-local address fix for rdma_resolve_addr

David J. Wilder
2009-10-15T19:27:21Z

On Wed, 2009-10-14 at 13:09 Jason Gunthorpe wrote:

> So, it tries to match the source addr to the addrs bound to the
> device, which is wrong - that isn't how the ip stack works.

> You can patch this up a little bit by fixing up addr_resolve_local to
> set sin6_scope_ip.

I found the bug in addr_resolve_local(). (more comments below)

--- addr.c.1759 2009-10-13 15:57:48.000000000 -0500
+++ addr.c.ip_local 2009-10-15 14:03:50.000000000 -0500
@@ -390,14 +390,17 @@ static int addr_resolve_local(struct soc
case AF_INET6:
{
struct in6_addr *a;
+ int found = 0;

for_each_netdev(&init_net, dev)
if (ipv6_chk_addr(&init_net,
&((struct sockaddr_in6 *) dst_in)->sin6_addr,
- dev, 1))
+ dev, 1)){
+ found = 1;
break;
+ }

- if (!dev)
+ if (!found)
return -EADDRNOTAVAIL;

a = &((struct sockaddr_in6 *) src_in)->sin6_addr;
@@ -406,6 +409,8 @@ static int addr_resolve_local(struct soc
src_in->sa_family = dst_in->sa_family;
((struct sockaddr_in6 *) src_in)->sin6_addr =
((struct sockaddr_in6 *) dst_in)->sin6_addr;
+ ((struct sockaddr_in6 *) src_in)->sin6_scope_id =
+ ((struct sockaddr_in6 *) dst_in)->sin6_scope_id;
ret = rdma_copy_addr(addr, dev, dev->dev_addr);
} else if (ipv6_addr_loopback(a)) {
ret = rdma_translate_ip(dst_in, addr);

> But really the correct thing to do is to remove addr_resolve_local and
> place the source address into the struct flowi and use the result of
> the route lookup to bind to the source device, and set the source
> address if it is unset.

Sorry I don't get it..
Are you saying that ip6_route_output() will resolve the address even if
it is a link-local address bound to my own interface? Therefor
addr_resolve_local() is not needed.