# \[PATCH net-next 06/22\] ipv4: redirect dst output to lwtunnel output

- From: Thomas Graf \<tgraf@suug.ch\>
- Date: 2015-07-17 12:55:53 
- List: netdev
- Page: https://ratatoskr.run/netdev/2015/07/10992036
- Thread: https://ratatoskr.run/netdev/2015/07/10992035/t.md

```text
From: Roopa Prabhu <redacted>

For input routes with tunnel encap state this patch redirects
dst output functions to lwtunnel_output which later resolves to
the corresponding lwtunnel output function.

This has been tested to work with mpls ip tunnels.

Open items: Support for tunnel mtu, pmtu, fragmentation can be
added by hooking into the corresponding (ipv4, ipv6) dst ops.
We may do this differently when lwtstate moves to dst or dst_metadata
as per upstream discussions.

Signed-off-by: Roopa Prabhu <redacted>
---
 net/ipv4/route.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 226570b..cd3157c 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1633,6 +1633,8 @@ static int __mkroute_input(struct sk_buff *skb,
 	rth->dst.output = ip_output;
 
 	rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
+	if (lwtunnel_output_redirect(rth->rt_lwtstate))
+		rth->dst.output = lwtunnel_output;
 	skb_dst_set(skb, &rth->dst);
 out:
 	err = 0;
-- 
2.4.3
```