[PATCHv5 net-next 01/16] udp: check udp sock encap_type in __udp_lib_err

[Xin Long]

There is a chance that __udp4/6_lib_lookup() returns a udp encap
sock in __udp_lib_err(), like the udp encap listening sock may
use the same port as remote encap port, in which case it should
go to __udp4/6_lib_err_encap() for more validation before
processing the icmp packet.

This patch is to check encap_type in __udp_lib_err() for the
further validation for a encap sock.

Signed-off-by: Xin Long <lucien....@gmail.com>
---
 net/ipv4/udp.c | 2 +-
 net/ipv6/udp.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 09f0a23..ca04a8a 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -702,7 +702,7 @@ int __udp4_lib_err(struct sk_buff *skb, u32 info, struct 
udp_table *udptable)
        sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
                               iph->saddr, uh->source, skb->dev->ifindex,
                               inet_sdif(skb), udptable, NULL);
-       if (!sk) {
+       if (!sk || udp_sk(sk)->encap_type) {
                /* No socket for error: try tunnels before discarding */
                sk = ERR_PTR(-ENOENT);
                if (static_branch_unlikely(&udp_encap_needed_key)) {
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 29d9691..cde9b88 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -560,7 +560,7 @@ int __udp6_lib_err(struct sk_buff *skb, struct 
inet6_skb_parm *opt,
 
        sk = __udp6_lib_lookup(net, daddr, uh->dest, saddr, uh->source,
                               inet6_iif(skb), inet6_sdif(skb), udptable, NULL);
-       if (!sk) {
+       if (!sk || udp_sk(sk)->encap_type) {
                /* No socket for error: try tunnels before discarding */
                sk = ERR_PTR(-ENOENT);
                if (static_branch_unlikely(&udpv6_encap_needed_key)) {
-- 
2.1.0