diff --git a/include/linux/udp.h b/include/linux/udp.h
index 0a9c54e76305abc4241fb2fc769e58c48ecef61e..2725c83395bfdd9e0ca0b78a1859bb6203af9f1c 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -77,6 +77,7 @@ struct udp_sock {
* For encapsulation sockets.
*/
int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
+ int (*encap_err_lookup)(struct sock *sk, struct sk_buff *skb);
void (*encap_destroy)(struct sock *sk);
/* GRO functions for UDP socket */
diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
index 3fbe56430e3b381749fe97f006e2b66332e18447..dc8d804af3b4d283f88d0d68b7a8c5410cdaac16 100644
--- a/include/net/udp_tunnel.h
+++ b/include/net/udp_tunnel.h
@@ -64,6 +64,8 @@ static inline int udp_sock_create(struct net *net,
}
typedef int (*udp_tunnel_encap_rcv_t)(struct sock *sk, struct sk_buff *skb);
+typedef int (*udp_tunnel_encap_err_lookup_t)(struct sock *sk,
+ struct sk_buff *skb);
typedef void (*udp_tunnel_encap_destroy_t)(struct sock *sk);
typedef struct sk_buff *(*udp_tunnel_gro_receive_t)(struct sock *sk,
struct list_head *head,
@@ -76,6 +78,7 @@ struct udp_tunnel_sock_cfg {
/* Used for setting up udp_sock fields, see udp.h for details */
__u8 encap_type;
udp_tunnel_encap_rcv_t encap_rcv;
+ udp_tunnel_encap_err_lookup_t encap_err_lookup;
udp_tunnel_encap_destroy_t encap_destroy;
udp_tunnel_gro_receive_t gro_receive;
udp_tunnel_gro_complete_t gro_complete;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 3488650b90ac3a97467fef6c64a3d42f73887568..ce759b61f6cde206fe060bc1ef41929cbf663506 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 6539ff15e9a3420db867bc2174aab3e196f97e43..d0c412fc56adcdff4c0df10d5e1546e6ba1368eb 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;
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index c55698d19d6847f0dab33d3b222a8e02fc81df95..1216c920f945999d3d346c01cbaaefec3a1abfc9 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -462,6 +462,61 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
goto try_again;
}
+DEFINE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
+void udpv6_encap_enable(void)
+{
+ static_branch_enable(&udpv6_encap_needed_key);
+}
+EXPORT_SYMBOL(udpv6_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 *__udp6_lib_err_encap(struct net *net,
+ const struct ipv6hdr *hdr, int offset,
+ 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 = __udp6_lib_lookup(net, &hdr->daddr, uh->source,
+ &hdr->saddr, uh->dest,
+ inet6_iif(skb), 0, udptable, skb);
+ if (!sk)
+ return NULL;
+
+ network_offset = skb_network_offset(skb);
+ transport_offset = skb_transport_offset(skb);
+
+ /* Network header needs to point to the outer IPv6 header inside ICMP */
+ skb_reset_network_header(skb);
+
+ /* Transport header needs to point to the UDP header */
+ skb_set_transport_header(skb, offset);
+
+ 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;
+}
+
void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
u8 type, u8 code, int offset, __be32 info,
struct udp_table *udptable)
@@ -471,6 +526,7 @@ void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
const struct in6_addr *saddr = &hdr->saddr;
const struct in6_addr *daddr = &hdr->daddr;
struct udphdr *uh = (struct udphdr *)(skb->data+offset);
+ bool tunnel = false;
struct sock *sk;
int harderr;
int err;
@@ -479,9 +535,18 @@ void __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, skb);
if (!sk) {
- __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
- ICMP6_MIB_INERRORS);
- return;
+ /* No socket for error: try tunnels before discarding */
+ if (static_branch_unlikely(&udpv6_encap_needed_key)) {
+ sk = __udp6_lib_err_encap(net, hdr, offset, uh,
+ udptable, skb);
+ }
+
+ if (!sk) {
+ __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
+ ICMP6_MIB_INERRORS);
+ return;
+ }
+ tunnel = true;
}
harderr = icmpv6_err_convert(type, code, &err);
@@ -495,10 +560,19 @@ void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
harderr = 1;
}
if (type == NDISC_REDIRECT) {
- ip6_sk_redirect(skb, sk);
+ if (tunnel) {
+ ip6_redirect(skb, sock_net(sk), inet6_iif(skb),
+ sk->sk_mark, sk->sk_uid);
+ } else {
+ ip6_sk_redirect(skb, sk);
+ }
goto out;
}
+ /* Tunnels don't have an application socket: don't pass errors back */
+ if (tunnel)
+ goto out;
+
if (!np->recverr) {
if (!harderr || sk->sk_state != TCP_ESTABLISHED)
goto out;
@@ -547,13 +621,6 @@ static __inline__ void udpv6_err(struct sk_buff *skb,
__udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
}
-DEFINE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
-void udpv6_encap_enable(void)
-{
- static_branch_enable(&udpv6_encap_needed_key);
-}
-EXPORT_SYMBOL(udpv6_encap_enable);
-
static int udpv6_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
{
struct udp_sock *up = udp_sk(sk);