6.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Paolo Abeni pabeni@redhat.com
[ Upstream commit a36283e2b683f172aa1760c77325e50b16c0f792 ]
Most UDP tunnels bind a socket to a local port, with ANY address, no peer and no interface index specified. Additionally it's quite common to have a single tunnel device per namespace.
Track in each namespace the UDP tunnel socket respecting the above. When only a single one is present, store a reference in the netns.
When such reference is not NULL, UDP tunnel GRO lookup just need to match the incoming packet destination port vs the socket local port.
The tunnel socket never sets the reuse[port] flag[s]. When bound to no address and interface, no other socket can exist in the same netns matching the specified local port.
Matching packets with non-local destination addresses will be aggregated, and eventually segmented as needed - no behavior changes intended.
Restrict the optimization to kernel sockets only: it covers all the relevant use-cases, and user-space owned sockets could be disconnected and rebound after setup_udp_tunnel_sock(), breaking the uniqueness assumption
Note that the UDP tunnel socket reference is stored into struct netns_ipv4 for both IPv4 and IPv6 tunnels. That is intentional to keep all the fastpath-related netns fields in the same struct and allow cacheline-based optimization. Currently both the IPv4 and IPv6 socket pointer share the same cacheline as the `udp_table` field.
Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Willem de Bruijn willemb@google.com Link: https://patch.msgid.link/41d16bc8d1257d567f9344c445b4ae0b4a91ede4.1744040675... Signed-off-by: Jakub Kicinski kuba@kernel.org Stable-dep-of: c26c192c3d48 ("udp: properly deal with xfrm encap and ADDRFORM") Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/udp.h | 16 ++++++++++++++++ include/net/netns/ipv4.h | 11 +++++++++++ include/net/udp.h | 1 + include/net/udp_tunnel.h | 12 ++++++++++++ net/ipv4/udp.c | 13 ++++++++++++- net/ipv4/udp_offload.c | 37 +++++++++++++++++++++++++++++++++++++ net/ipv4/udp_tunnel_core.c | 13 +++++++++++++ net/ipv6/udp.c | 2 ++ net/ipv6/udp_offload.c | 5 +++++ 9 files changed, 109 insertions(+), 1 deletion(-)
diff --git a/include/linux/udp.h b/include/linux/udp.h index 0807e21cfec95..895240177f4f4 100644 --- a/include/linux/udp.h +++ b/include/linux/udp.h @@ -101,6 +101,13 @@ struct udp_sock {
/* Cache friendly copy of sk->sk_peek_off >= 0 */ bool peeking_with_offset; + + /* + * Accounting for the tunnel GRO fastpath. + * Unprotected by compilers guard, as it uses space available in + * the last UDP socket cacheline. + */ + struct hlist_node tunnel_list; };
#define udp_test_bit(nr, sk) \ @@ -219,4 +226,13 @@ static inline void udp_allow_gso(struct sock *sk)
#define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE)
+static inline struct sock *udp_tunnel_sk(const struct net *net, bool is_ipv6) +{ +#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL) + return rcu_dereference(net->ipv4.udp_tunnel_gro[is_ipv6].sk); +#else + return NULL; +#endif +} + #endif /* _LINUX_UDP_H */ diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h index 650b2dc9199f4..6373e3f17da84 100644 --- a/include/net/netns/ipv4.h +++ b/include/net/netns/ipv4.h @@ -47,6 +47,11 @@ struct sysctl_fib_multipath_hash_seed { }; #endif
+struct udp_tunnel_gro { + struct sock __rcu *sk; + struct hlist_head list; +}; + struct netns_ipv4 { /* Cacheline organization can be found documented in * Documentation/networking/net_cachelines/netns_ipv4_sysctl.rst. @@ -85,6 +90,11 @@ struct netns_ipv4 { struct inet_timewait_death_row tcp_death_row; struct udp_table *udp_table;
+#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL) + /* Not in a pernet subsys because need to be available at GRO stage */ + struct udp_tunnel_gro udp_tunnel_gro[2]; +#endif + #ifdef CONFIG_SYSCTL struct ctl_table_header *forw_hdr; struct ctl_table_header *frags_hdr; @@ -277,4 +287,5 @@ struct netns_ipv4 { struct hlist_head *inet_addr_lst; struct delayed_work addr_chk_work; }; + #endif diff --git a/include/net/udp.h b/include/net/udp.h index 6e89520e100dc..a772510b2aa58 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -290,6 +290,7 @@ static inline void udp_lib_init_sock(struct sock *sk) struct udp_sock *up = udp_sk(sk);
skb_queue_head_init(&up->reader_queue); + INIT_HLIST_NODE(&up->tunnel_list); up->forward_threshold = sk->sk_rcvbuf >> 2; set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags); } diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h index a93dc51f6323e..1bb2b852e90eb 100644 --- a/include/net/udp_tunnel.h +++ b/include/net/udp_tunnel.h @@ -191,6 +191,18 @@ static inline int udp_tunnel_handle_offloads(struct sk_buff *skb, bool udp_csum) } #endif
+#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL) +void udp_tunnel_update_gro_lookup(struct net *net, struct sock *sk, bool add); +#else +static inline void udp_tunnel_update_gro_lookup(struct net *net, + struct sock *sk, bool add) {} +#endif + +static inline void udp_tunnel_cleanup_gro(struct sock *sk) +{ + udp_tunnel_update_gro_lookup(sock_net(sk), sk, false); +} + static inline void udp_tunnel_encap_enable(struct sock *sk) { if (udp_test_and_set_bit(ENCAP_ENABLED, sk)) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 2742cc7602bb5..04cd3353f1d46 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2897,8 +2897,10 @@ void udp_destroy_sock(struct sock *sk) if (encap_destroy) encap_destroy(sk); } - if (udp_test_bit(ENCAP_ENABLED, sk)) + if (udp_test_bit(ENCAP_ENABLED, sk)) { static_branch_dec(&udp_encap_needed_key); + udp_tunnel_cleanup_gro(sk); + } } }
@@ -3810,6 +3812,15 @@ static void __net_init udp_set_table(struct net *net)
static int __net_init udp_pernet_init(struct net *net) { +#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL) + int i; + + /* No tunnel is configured */ + for (i = 0; i < ARRAY_SIZE(net->ipv4.udp_tunnel_gro); ++i) { + INIT_HLIST_HEAD(&net->ipv4.udp_tunnel_gro[i].list); + RCU_INIT_POINTER(net->ipv4.udp_tunnel_gro[i].sk, NULL); + } +#endif udp_sysctl_init(net); udp_set_table(net);
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index 9a8142ccbabe4..67641945ba3a3 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -12,6 +12,38 @@ #include <net/udp.h> #include <net/protocol.h> #include <net/inet_common.h> +#include <net/udp_tunnel.h> + +#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL) +static DEFINE_SPINLOCK(udp_tunnel_gro_lock); + +void udp_tunnel_update_gro_lookup(struct net *net, struct sock *sk, bool add) +{ + bool is_ipv6 = sk->sk_family == AF_INET6; + struct udp_sock *tup, *up = udp_sk(sk); + struct udp_tunnel_gro *udp_tunnel_gro; + + spin_lock(&udp_tunnel_gro_lock); + udp_tunnel_gro = &net->ipv4.udp_tunnel_gro[is_ipv6]; + if (add) + hlist_add_head(&up->tunnel_list, &udp_tunnel_gro->list); + else if (up->tunnel_list.pprev) + hlist_del_init(&up->tunnel_list); + + if (udp_tunnel_gro->list.first && + !udp_tunnel_gro->list.first->next) { + tup = hlist_entry(udp_tunnel_gro->list.first, struct udp_sock, + tunnel_list); + + rcu_assign_pointer(udp_tunnel_gro->sk, (struct sock *)tup); + } else { + RCU_INIT_POINTER(udp_tunnel_gro->sk, NULL); + } + + spin_unlock(&udp_tunnel_gro_lock); +} +EXPORT_SYMBOL_GPL(udp_tunnel_update_gro_lookup); +#endif
static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, netdev_features_t features, @@ -694,8 +726,13 @@ static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport, { const struct iphdr *iph = skb_gro_network_header(skb); struct net *net = dev_net_rcu(skb->dev); + struct sock *sk; int iif, sdif;
+ sk = udp_tunnel_sk(net, false); + if (sk && dport == htons(sk->sk_num)) + return sk; + inet_get_iif_sdif(skb, &iif, &sdif);
return __udp4_lib_lookup(net, iph->saddr, sport, diff --git a/net/ipv4/udp_tunnel_core.c b/net/ipv4/udp_tunnel_core.c index 619a53eb672da..3d1214e6df0ea 100644 --- a/net/ipv4/udp_tunnel_core.c +++ b/net/ipv4/udp_tunnel_core.c @@ -58,6 +58,15 @@ int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg, } EXPORT_SYMBOL(udp_sock_create4);
+static bool sk_saddr_any(struct sock *sk) +{ +#if IS_ENABLED(CONFIG_IPV6) + return ipv6_addr_any(&sk->sk_v6_rcv_saddr); +#else + return !sk->sk_rcv_saddr; +#endif +} + void setup_udp_tunnel_sock(struct net *net, struct socket *sock, struct udp_tunnel_sock_cfg *cfg) { @@ -80,6 +89,10 @@ void setup_udp_tunnel_sock(struct net *net, struct socket *sock, udp_sk(sk)->gro_complete = cfg->gro_complete;
udp_tunnel_encap_enable(sk); + + if (!sk->sk_dport && !sk->sk_bound_dev_if && sk_saddr_any(sk) && + sk->sk_kern_sock) + udp_tunnel_update_gro_lookup(net, sk, true); } EXPORT_SYMBOL_GPL(setup_udp_tunnel_sock);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 024458ef163c9..7317f8e053f1c 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -46,6 +46,7 @@ #include <net/tcp_states.h> #include <net/ip6_checksum.h> #include <net/ip6_tunnel.h> +#include <net/udp_tunnel.h> #include <net/xfrm.h> #include <net/inet_hashtables.h> #include <net/inet6_hashtables.h> @@ -1825,6 +1826,7 @@ void udpv6_destroy_sock(struct sock *sk) if (udp_test_bit(ENCAP_ENABLED, sk)) { static_branch_dec(&udpv6_encap_needed_key); udp_encap_disable(); + udp_tunnel_cleanup_gro(sk); } } } diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c index 404212dfc99ab..d8445ac1b2e43 100644 --- a/net/ipv6/udp_offload.c +++ b/net/ipv6/udp_offload.c @@ -118,8 +118,13 @@ static struct sock *udp6_gro_lookup_skb(struct sk_buff *skb, __be16 sport, { const struct ipv6hdr *iph = skb_gro_network_header(skb); struct net *net = dev_net_rcu(skb->dev); + struct sock *sk; int iif, sdif;
+ sk = udp_tunnel_sk(net, true); + if (sk && dport == htons(sk->sk_num)) + return sk; + inet6_get_iif_sdif(skb, &iif, &sdif);
return __udp6_lib_lookup(net, &iph->saddr, sport,