soreuseport: fast reuseport TCP socket selection
This change extends the fast SO_REUSEPORT socket lookup implemented
for UDP to TCP. Listener sockets with SO_REUSEPORT and the same
receive address are additionally added to an array for faster
random access. This means that only a single socket from the group
must be found in the listener list before any socket in the group can
be used to receive a packet. Previously, every socket in the group
needed to be considered before handing off the incoming packet.
This feature also exposes the ability to use a BPF program when
selecting a socket from a reuseport group.
Signed-off-by: Craig Gallek <kraig@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 5e4290b..c0f9942 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -20,10 +20,12 @@
#include <linux/wait.h>
#include <linux/vmalloc.h>
+#include <net/addrconf.h>
#include <net/inet_connection_sock.h>
#include <net/inet_hashtables.h>
#include <net/secure_seq.h>
#include <net/ip.h>
+#include <net/sock_reuseport.h>
static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
const __u16 lport, const __be32 faddr,
@@ -215,6 +217,7 @@
unsigned int hash = inet_lhashfn(net, hnum);
struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
int score, hiscore, matches = 0, reuseport = 0;
+ bool select_ok = true;
u32 phash = 0;
rcu_read_lock();
@@ -230,6 +233,15 @@
if (reuseport) {
phash = inet_ehashfn(net, daddr, hnum,
saddr, sport);
+ if (select_ok) {
+ struct sock *sk2;
+ sk2 = reuseport_select_sock(sk, phash,
+ skb, doff);
+ if (sk2) {
+ result = sk2;
+ goto found;
+ }
+ }
matches = 1;
}
} else if (score == hiscore && reuseport) {
@@ -247,11 +259,13 @@
if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
goto begin;
if (result) {
+found:
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, hnum, daddr,
dif) < hiscore)) {
sock_put(result);
+ select_ok = false;
goto begin;
}
}
@@ -450,34 +464,74 @@
}
EXPORT_SYMBOL_GPL(inet_ehash_nolisten);
-void __inet_hash(struct sock *sk, struct sock *osk)
+static int inet_reuseport_add_sock(struct sock *sk,
+ struct inet_listen_hashbucket *ilb,
+ int (*saddr_same)(const struct sock *sk1,
+ const struct sock *sk2,
+ bool match_wildcard))
+{
+ struct sock *sk2;
+ struct hlist_nulls_node *node;
+ kuid_t uid = sock_i_uid(sk);
+
+ sk_nulls_for_each_rcu(sk2, node, &ilb->head) {
+ if (sk2 != sk &&
+ sk2->sk_family == sk->sk_family &&
+ ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
+ sk2->sk_bound_dev_if == sk->sk_bound_dev_if &&
+ sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
+ saddr_same(sk, sk2, false))
+ return reuseport_add_sock(sk, sk2);
+ }
+
+ /* Initial allocation may have already happened via setsockopt */
+ if (!rcu_access_pointer(sk->sk_reuseport_cb))
+ return reuseport_alloc(sk);
+ return 0;
+}
+
+int __inet_hash(struct sock *sk, struct sock *osk,
+ int (*saddr_same)(const struct sock *sk1,
+ const struct sock *sk2,
+ bool match_wildcard))
{
struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
struct inet_listen_hashbucket *ilb;
+ int err = 0;
if (sk->sk_state != TCP_LISTEN) {
inet_ehash_nolisten(sk, osk);
- return;
+ return 0;
}
WARN_ON(!sk_unhashed(sk));
ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
spin_lock(&ilb->lock);
+ if (sk->sk_reuseport) {
+ err = inet_reuseport_add_sock(sk, ilb, saddr_same);
+ if (err)
+ goto unlock;
+ }
__sk_nulls_add_node_rcu(sk, &ilb->head);
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
+unlock:
spin_unlock(&ilb->lock);
+
+ return err;
}
EXPORT_SYMBOL(__inet_hash);
int inet_hash(struct sock *sk)
{
+ int err = 0;
+
if (sk->sk_state != TCP_CLOSE) {
local_bh_disable();
- __inet_hash(sk, NULL);
+ err = __inet_hash(sk, NULL, ipv4_rcv_saddr_equal);
local_bh_enable();
}
- return 0;
+ return err;
}
EXPORT_SYMBOL_GPL(inet_hash);
@@ -496,6 +550,8 @@
lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
spin_lock_bh(lock);
+ if (rcu_access_pointer(sk->sk_reuseport_cb))
+ reuseport_detach_sock(sk);
done = __sk_nulls_del_node_init_rcu(sk);
if (done)
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);