diff options
Diffstat (limited to 'net/ipv4/udp.c')
| -rw-r--r-- | net/ipv4/udp.c | 121 |
1 files changed, 108 insertions, 13 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 3488650b90ac..6f8890c5bc7e 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -105,6 +105,7 @@ #include <net/net_namespace.h> #include <net/icmp.h> #include <net/inet_hashtables.h> +#include <net/ip_tunnels.h> #include <net/route.h> #include <net/checksum.h> #include <net/xfrm.h> @@ -583,6 +584,89 @@ 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); + +/* Handler for tunnels with arbitrary destination ports: no socket lookup, go + * through error handlers in encapsulations looking for a match. + */ +static int __udp4_lib_err_encap_no_sk(struct sk_buff *skb, u32 info) +{ + int i; + + for (i = 0; i < MAX_IPTUN_ENCAP_OPS; i++) { + int (*handler)(struct sk_buff *skb, u32 info); + + if (!iptun_encaps[i]) + continue; + handler = rcu_dereference(iptun_encaps[i]->err_handler); + if (handler && !handler(skb, info)) + return 0; + } + + return -ENOENT; +} + +/* 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. + * + * If this doesn't match any socket, probe tunnels with arbitrary destination + * ports (e.g. FoU, GUE): there, the receiving socket is useless, as the port + * we've sent packets to won't necessarily match the local destination port. + * + * Then ask the tunnel implementation to match the error against a valid + * association. + * + * Return an error if we can't find a match, the socket if we need further + * processing, zero otherwise. + */ +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, u32 info) +{ + int network_offset, transport_offset; + struct sock *sk; + + 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); + + sk = __udp4_lib_lookup(net, iph->daddr, uh->source, + iph->saddr, uh->dest, skb->dev->ifindex, 0, + udptable, NULL); + if (sk) { + int (*lookup)(struct sock *sk, struct sk_buff *skb); + struct udp_sock *up = udp_sk(sk); + + lookup = READ_ONCE(up->encap_err_lookup); + if (!lookup || lookup(sk, skb)) + sk = NULL; + } + + if (!sk) + sk = ERR_PTR(__udp4_lib_err_encap_no_sk(skb, info)); + + 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 @@ -594,13 +678,14 @@ static inline bool __udp_is_mcast_sock(struct net *net, struct sock *sk, * to find the appropriate port. */ -void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable) +int __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable) { struct inet_sock *inet; const struct iphdr *iph = (const struct iphdr *)skb->data; 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 +695,21 @@ 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 */ + sk = ERR_PTR(-ENOENT); + if (static_branch_unlikely(&udp_encap_needed_key)) { + sk = __udp4_lib_err_encap(net, iph, uh, udptable, skb, + info); + if (!sk) + return 0; + } + + if (IS_ERR(sk)) { + __ICMP_INC_STATS(net, ICMP_MIB_INERRORS); + return PTR_ERR(sk); + } + + tunnel = true; } err = 0; @@ -654,6 +752,10 @@ 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; @@ -663,12 +765,12 @@ void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable) sk->sk_err = err; sk->sk_error_report(sk); out: - return; + return 0; } -void udp_err(struct sk_buff *skb, u32 info) +int udp_err(struct sk_buff *skb, u32 info) { - __udp4_lib_err(skb, info, &udp_table); + return __udp4_lib_err(skb, info, &udp_table); } /* @@ -1891,13 +1993,6 @@ 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 |