From: Willem de Bruijn willemb@google.com
[ Upstream commit acdcecc61285faed359f1a3568c32089cc3a8329 ]
UDP reuseport groups can hold a mix unconnected and connected sockets. Ensure that connections only receive all traffic to their 4-tuple.
Fast reuseport returns on the first reuseport match on the assumption that all matches are equal. Only if connections are present, return to the previous behavior of scoring all sockets.
Record if connections are present and if so (1) treat such connected sockets as an independent match from the group, (2) only return 2-tuple matches from reuseport and (3) do not return on the first 2-tuple reuseport match to allow for a higher scoring match later.
New field has_conns is set without locks. No other fields in the bitmap are modified at runtime and the field is only ever set unconditionally, so an RMW cannot miss a change.
Fixes: e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection") Link: http://lkml.kernel.org/r/CA+FuTSfRP09aJNYRt04SS6qj22ViiOEWaWmLAwX0psk8-PGNxw... Signed-off-by: Willem de Bruijn willemb@google.com Acked-by: Paolo Abeni pabeni@redhat.com Acked-by: Craig Gallek kraig@google.com Signed-off-by: Willem de Bruijn willemb@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/sock_reuseport.h | 21 ++++++++++++++++++++- net/core/sock_reuseport.c | 15 +++++++++++++-- net/ipv4/datagram.c | 2 ++ net/ipv4/udp.c | 5 +++-- net/ipv6/datagram.c | 2 ++ net/ipv6/udp.c | 5 +++-- 6 files changed, 43 insertions(+), 7 deletions(-)
--- a/include/net/sock_reuseport.h +++ b/include/net/sock_reuseport.h @@ -21,7 +21,8 @@ struct sock_reuseport { unsigned int synq_overflow_ts; /* ID stays the same even after the size of socks[] grows. */ unsigned int reuseport_id; - bool bind_inany; + unsigned int bind_inany:1; + unsigned int has_conns:1; struct bpf_prog __rcu *prog; /* optional BPF sock selector */ struct sock *socks[0]; /* array of sock pointers */ }; @@ -35,6 +36,24 @@ extern struct sock *reuseport_select_soc struct sk_buff *skb, int hdr_len); extern int reuseport_attach_prog(struct sock *sk, struct bpf_prog *prog); + +static inline bool reuseport_has_conns(struct sock *sk, bool set) +{ + struct sock_reuseport *reuse; + bool ret = false; + + rcu_read_lock(); + reuse = rcu_dereference(sk->sk_reuseport_cb); + if (reuse) { + if (set) + reuse->has_conns = 1; + ret = reuse->has_conns; + } + rcu_read_unlock(); + + return ret; +} + int reuseport_get_id(struct sock_reuseport *reuse);
#endif /* _SOCK_REUSEPORT_H */ --- a/net/core/sock_reuseport.c +++ b/net/core/sock_reuseport.c @@ -295,8 +295,19 @@ struct sock *reuseport_select_sock(struc
select_by_hash: /* no bpf or invalid bpf result: fall back to hash usage */ - if (!sk2) - sk2 = reuse->socks[reciprocal_scale(hash, socks)]; + if (!sk2) { + int i, j; + + i = j = reciprocal_scale(hash, socks); + while (reuse->socks[i]->sk_state == TCP_ESTABLISHED) { + i++; + if (i >= reuse->num_socks) + i = 0; + if (i == j) + goto out; + } + sk2 = reuse->socks[i]; + } }
out: --- a/net/ipv4/datagram.c +++ b/net/ipv4/datagram.c @@ -15,6 +15,7 @@ #include <net/sock.h> #include <net/route.h> #include <net/tcp_states.h> +#include <net/sock_reuseport.h>
int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) { @@ -69,6 +70,7 @@ int __ip4_datagram_connect(struct sock * } inet->inet_daddr = fl4->daddr; inet->inet_dport = usin->sin_port; + reuseport_has_conns(sk, true); sk->sk_state = TCP_ESTABLISHED; sk_set_txhash(sk); inet->inet_id = jiffies; --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -434,12 +434,13 @@ static struct sock *udp4_lib_lookup2(str score = compute_score(sk, net, saddr, sport, daddr, hnum, dif, sdif, exact_dif); if (score > badness) { - if (sk->sk_reuseport) { + if (sk->sk_reuseport && + sk->sk_state != TCP_ESTABLISHED) { hash = udp_ehashfn(net, daddr, hnum, saddr, sport); result = reuseport_select_sock(sk, hash, skb, sizeof(struct udphdr)); - if (result) + if (result && !reuseport_has_conns(sk, false)) return result; } badness = score; --- a/net/ipv6/datagram.c +++ b/net/ipv6/datagram.c @@ -27,6 +27,7 @@ #include <net/ip6_route.h> #include <net/tcp_states.h> #include <net/dsfield.h> +#include <net/sock_reuseport.h>
#include <linux/errqueue.h> #include <linux/uaccess.h> @@ -254,6 +255,7 @@ ipv4_connected: goto out; }
+ reuseport_has_conns(sk, true); sk->sk_state = TCP_ESTABLISHED; sk_set_txhash(sk); out: --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -168,13 +168,14 @@ static struct sock *udp6_lib_lookup2(str score = compute_score(sk, net, saddr, sport, daddr, hnum, dif, sdif, exact_dif); if (score > badness) { - if (sk->sk_reuseport) { + if (sk->sk_reuseport && + sk->sk_state != TCP_ESTABLISHED) { hash = udp6_ehashfn(net, daddr, hnum, saddr, sport);
result = reuseport_select_sock(sk, hash, skb, sizeof(struct udphdr)); - if (result) + if (result && !reuseport_has_conns(sk, false)) return result; } result = sk;