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-rw-r--r--net/ipv4/udp.c79
-rw-r--r--net/ipv4/udp_tunnel.c1
2 files changed, 71 insertions, 9 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 3488650b90ac..ce759b61f6cd 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -583,6 +583,62 @@ static inline bool __udp_is_mcast_sock(struct net *net, struct sock *sk,
return true;
}
+DEFINE_STATIC_KEY_FALSE(udp_encap_needed_key);
+void udp_encap_enable(void)
+{
+ static_branch_enable(&udp_encap_needed_key);
+}
+EXPORT_SYMBOL(udp_encap_enable);
+
+/* Try to match ICMP errors to UDP tunnels by looking up a socket without
+ * reversing source and destination port: this will match tunnels that force the
+ * same destination port on both endpoints (e.g. VXLAN, GENEVE). Note that
+ * lwtunnels might actually break this assumption by being configured with
+ * different destination ports on endpoints, in this case we won't be able to
+ * trace ICMP messages back to them.
+ *
+ * Then ask the tunnel implementation to match the error against a valid
+ * association.
+ *
+ * Return the socket if we have a match.
+ */
+static struct sock *__udp4_lib_err_encap(struct net *net,
+ const struct iphdr *iph,
+ struct udphdr *uh,
+ struct udp_table *udptable,
+ struct sk_buff *skb)
+{
+ int (*lookup)(struct sock *sk, struct sk_buff *skb);
+ int network_offset, transport_offset;
+ struct udp_sock *up;
+ struct sock *sk;
+
+ sk = __udp4_lib_lookup(net, iph->daddr, uh->source,
+ iph->saddr, uh->dest, skb->dev->ifindex, 0,
+ udptable, NULL);
+ if (!sk)
+ return NULL;
+
+ network_offset = skb_network_offset(skb);
+ transport_offset = skb_transport_offset(skb);
+
+ /* Network header needs to point to the outer IPv4 header inside ICMP */
+ skb_reset_network_header(skb);
+
+ /* Transport header needs to point to the UDP header */
+ skb_set_transport_header(skb, iph->ihl << 2);
+
+ up = udp_sk(sk);
+ lookup = READ_ONCE(up->encap_err_lookup);
+ if (!lookup || lookup(sk, skb))
+ sk = NULL;
+
+ skb_set_transport_header(skb, transport_offset);
+ skb_set_network_header(skb, network_offset);
+
+ return sk;
+}
+
/*
* This routine is called by the ICMP module when it gets some
* sort of error condition. If err < 0 then the socket should
@@ -601,6 +657,7 @@ void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
const int type = icmp_hdr(skb)->type;
const int code = icmp_hdr(skb)->code;
+ bool tunnel = false;
struct sock *sk;
int harderr;
int err;
@@ -610,8 +667,15 @@ void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
iph->saddr, uh->source, skb->dev->ifindex,
inet_sdif(skb), udptable, NULL);
if (!sk) {
- __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
- return; /* No socket for error */
+ /* No socket for error: try tunnels before discarding */
+ if (static_branch_unlikely(&udp_encap_needed_key))
+ sk = __udp4_lib_err_encap(net, iph, uh, udptable, skb);
+
+ if (!sk) {
+ __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
+ return;
+ }
+ tunnel = true;
}
err = 0;
@@ -654,6 +718,10 @@ void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
* RFC1122: OK. Passes ICMP errors back to application, as per
* 4.1.3.3.
*/
+ if (tunnel) {
+ /* ...not for tunnels though: we don't have a sending socket */
+ goto out;
+ }
if (!inet->recverr) {
if (!harderr || sk->sk_state != TCP_ESTABLISHED)
goto out;
@@ -1891,13 +1959,6 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
return 0;
}
-DEFINE_STATIC_KEY_FALSE(udp_encap_needed_key);
-void udp_encap_enable(void)
-{
- static_branch_enable(&udp_encap_needed_key);
-}
-EXPORT_SYMBOL(udp_encap_enable);
-
/* returns:
* -1: error
* 0: success
diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c
index 6539ff15e9a3..d0c412fc56ad 100644
--- a/net/ipv4/udp_tunnel.c
+++ b/net/ipv4/udp_tunnel.c
@@ -68,6 +68,7 @@ void setup_udp_tunnel_sock(struct net *net, struct socket *sock,
udp_sk(sk)->encap_type = cfg->encap_type;
udp_sk(sk)->encap_rcv = cfg->encap_rcv;
+ udp_sk(sk)->encap_err_lookup = cfg->encap_err_lookup;
udp_sk(sk)->encap_destroy = cfg->encap_destroy;
udp_sk(sk)->gro_receive = cfg->gro_receive;
udp_sk(sk)->gro_complete = cfg->gro_complete;