Hello,
On Wed, 4 May 2016, David Ahern wrote:
> Allow udp and raw sockets to send by oif that is an enslaved interface
> versus the l3mdev/VRF device. For example, this allows BFD to use ifindex
> from IP_PKTINFO on a receive to send a response without the need to
> convert to the VRF index. It also allows ping and ping6 to work when
> specifying an enslaved interface (e.g., ping -I swp1 <ip>) which is
> a natural use case.
>
> Signed-off-by: David Ahern <d...@cumulusnetworks.com>
> ---
> drivers/net/vrf.c | 2 ++
> net/ipv4/route.c | 4 ++++
> net/l3mdev/l3mdev.c | 20 +++++++++++++++-----
> 3 files changed, 21 insertions(+), 5 deletions(-)
>
> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
> index 8c8c655bb2c4..a1f2830d8110 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
> @@ -2146,6 +2146,7 @@ struct rtable *__ip_route_output_key_hash(struct net
> *net, struct flowi4 *fl4,
> unsigned int flags = 0;
> struct fib_result res;
> struct rtable *rth;
> + int master_idx;
> int orig_oif;
> int err = -ENETUNREACH;
>
> @@ -2155,6 +2156,9 @@ struct rtable *__ip_route_output_key_hash(struct net
> *net, struct flowi4 *fl4,
>
> orig_oif = fl4->flowi4_oif;
>
> + master_idx = l3mdev_master_ifindex_by_index(net, fl4->flowi4_oif);
> + if (master_idx)
> + fl4->flowi4_oif = master_idx;
Changing the flowi4_oif at this point can have
bad effects. I remember for recent commit for __mkroute_output
where the route caching is disabled if traffic is redirected
to loopback. I think, such change can affect the route
caching, for example, now we use nexthop on master_idx to
cache routes for orig_oif. Such problems with the caching
in the past always caused lookups to return wrong cached result
for other users. But this is only my fears, I don't know
the actual result of this change. May be you are trying to
change flowi4_oif at one place instead of every caller.
Regards
--
Julian Anastasov <j...@ssi.bg>
