When using an ip6tnl device in collect_md mode, the xmit methods ignore
the ipv6.src field present in skb_tunnel_info's key, both for route
calculation purposes (flowi6 construction) and for assigning the
packet's final ipv6h->saddr.
This makes it impossible specifying a desired ipv6 local address in the
encapsulating header (for example, when using tc action tunnel_key).
This is also not aligned with behavior of ipip (ipv4) in collect_md
mode, where the key->u.ipv4.src gets used.
Fix, by assigning fl6.saddr with given key->u.ipv6.src.
In case ipv6.src is not specified, ip6_tnl_xmit uses existing saddr
selection code.
Signed-off-by: Shmulik Ladkani <shmulik.ladk...@gmail.com>
Reviewed-by: Eyal Birger <eyal.bir...@gmail.com>
Fixes: 8d79266bc48c ("ip6_tunnel: add collect_md mode to IPv6 tunnels")
---
net/ipv6/ip6_tunnel.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 00e138a44cbb..820cebe0c687 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1113,7 +1113,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device
*dev, __u8 dsfield,
dst = NULL;
goto tx_err_link_failure;
}
- if (t->parms.collect_md &&
+ if (t->parms.collect_md && ipv6_addr_any(&fl6->saddr) &&
ipv6_dev_get_saddr(net, ip6_dst_idev(dst)->dev,
&fl6->daddr, 0, &fl6->saddr))
goto tx_err_link_failure;
@@ -1255,6 +1255,7 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device
*dev)
key = &tun_info->key;
memset(&fl6, 0, sizeof(fl6));
fl6.flowi6_proto = IPPROTO_IPIP;
+ fl6.saddr = key->u.ipv6.src;
fl6.daddr = key->u.ipv6.dst;
fl6.flowlabel = key->label;
dsfield = key->tos;
@@ -1326,6 +1327,7 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device
*dev)
key = &tun_info->key;
memset(&fl6, 0, sizeof(fl6));
fl6.flowi6_proto = IPPROTO_IPV6;
+ fl6.saddr = key->u.ipv6.src;
fl6.daddr = key->u.ipv6.dst;
fl6.flowlabel = key->label;
dsfield = key->tos;
--
2.18.0
