tcp/dccp: install syn_recv requests into ehash table
In this patch, we insert request sockets into TCP/DCCP
regular ehash table (where ESTABLISHED and TIMEWAIT sockets
are) instead of using the per listener hash table.
ACK packets find SYN_RECV pseudo sockets without having
to find and lock the listener.
In nominal conditions, this halves pressure on listener lock.
Note that this will allow for SO_REUSEPORT refinements,
so that we can select a listener using cpu/numa affinities instead
of the prior 'consistent hash', since only SYN packets will
apply this selection logic.
We will shrink listen_sock in the following patch to ease
code review.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ying Cai <ycai@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a331016..bfe9d39 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1224,7 +1224,6 @@
.route_req = tcp_v4_route_req,
.init_seq = tcp_v4_init_sequence,
.send_synack = tcp_v4_send_synack,
- .queue_hash_add = inet_csk_reqsk_queue_hash_add,
};
int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
@@ -1343,34 +1342,11 @@
}
EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
-static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
+static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
{
- const struct tcphdr *th = tcp_hdr(skb);
- const struct iphdr *iph = ip_hdr(skb);
- struct request_sock *req;
- struct sock *nsk;
-
- req = inet_csk_search_req(sk, th->source, iph->saddr, iph->daddr);
- if (req) {
- nsk = tcp_check_req(sk, skb, req, false);
- if (!nsk || nsk == sk)
- reqsk_put(req);
- return nsk;
- }
-
- nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
- th->source, iph->daddr, th->dest, inet_iif(skb));
-
- if (nsk) {
- if (nsk->sk_state != TCP_TIME_WAIT) {
- bh_lock_sock(nsk);
- return nsk;
- }
- inet_twsk_put(inet_twsk(nsk));
- return NULL;
- }
-
#ifdef CONFIG_SYN_COOKIES
+ const struct tcphdr *th = tcp_hdr(skb);
+
if (!th->syn)
sk = cookie_v4_check(sk, skb);
#endif
@@ -1409,10 +1385,10 @@
goto csum_err;
if (sk->sk_state == TCP_LISTEN) {
- struct sock *nsk = tcp_v4_hnd_req(sk, skb);
+ struct sock *nsk = tcp_v4_cookie_check(sk, skb);
+
if (!nsk)
goto discard;
-
if (nsk != sk) {
sock_rps_save_rxhash(nsk, skb);
sk_mark_napi_id(nsk, skb);
@@ -1603,6 +1579,29 @@
if (sk->sk_state == TCP_TIME_WAIT)
goto do_time_wait;
+ if (sk->sk_state == TCP_NEW_SYN_RECV) {
+ struct request_sock *req = inet_reqsk(sk);
+ struct sock *nsk = NULL;
+
+ sk = req->rsk_listener;
+ if (tcp_v4_inbound_md5_hash(sk, skb))
+ goto discard_and_relse;
+ if (sk->sk_state == TCP_LISTEN)
+ nsk = tcp_check_req(sk, skb, req, false);
+ if (!nsk) {
+ reqsk_put(req);
+ goto discard_it;
+ }
+ if (nsk == sk) {
+ sock_hold(sk);
+ reqsk_put(req);
+ } else if (tcp_child_process(sk, nsk, skb)) {
+ tcp_v4_send_reset(nsk, skb);
+ goto discard_it;
+ } else {
+ return 0;
+ }
+ }
if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
goto discard_and_relse;
@@ -1830,35 +1829,7 @@
++st->num;
++st->offset;
- if (st->state == TCP_SEQ_STATE_OPENREQ) {
- struct request_sock *req = cur;
-
- icsk = inet_csk(st->syn_wait_sk);
- req = req->dl_next;
- while (1) {
- while (req) {
- if (req->rsk_ops->family == st->family) {
- cur = req;
- goto out;
- }
- req = req->dl_next;
- }
- if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
- break;
-get_req:
- req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
- }
- sk = sk_nulls_next(st->syn_wait_sk);
- st->state = TCP_SEQ_STATE_LISTENING;
- spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
- } else {
- icsk = inet_csk(sk);
- spin_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
- if (reqsk_queue_len(&icsk->icsk_accept_queue))
- goto start_req;
- spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
- sk = sk_nulls_next(sk);
- }
+ sk = sk_nulls_next(sk);
get_sk:
sk_nulls_for_each_from(sk, node) {
if (!net_eq(sock_net(sk), net))
@@ -1868,15 +1839,6 @@
goto out;
}
icsk = inet_csk(sk);
- spin_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
- if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
-start_req:
- st->syn_wait_sk = sk;
- st->state = TCP_SEQ_STATE_OPENREQ;
- st->sbucket = 0;
- goto get_req;
- }
- spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
}
spin_unlock_bh(&ilb->lock);
st->offset = 0;
@@ -2008,7 +1970,6 @@
void *rc = NULL;
switch (st->state) {
- case TCP_SEQ_STATE_OPENREQ:
case TCP_SEQ_STATE_LISTENING:
if (st->bucket >= INET_LHTABLE_SIZE)
break;
@@ -2067,7 +2028,6 @@
}
switch (st->state) {
- case TCP_SEQ_STATE_OPENREQ:
case TCP_SEQ_STATE_LISTENING:
rc = listening_get_next(seq, v);
if (!rc) {
@@ -2092,11 +2052,6 @@
struct tcp_iter_state *st = seq->private;
switch (st->state) {
- case TCP_SEQ_STATE_OPENREQ:
- if (v) {
- struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
- spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
- }
case TCP_SEQ_STATE_LISTENING:
if (v != SEQ_START_TOKEN)
spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
@@ -2269,18 +2224,12 @@
}
st = seq->private;
- switch (st->state) {
- case TCP_SEQ_STATE_LISTENING:
- case TCP_SEQ_STATE_ESTABLISHED:
- if (sk->sk_state == TCP_TIME_WAIT)
- get_timewait4_sock(v, seq, st->num);
- else
- get_tcp4_sock(v, seq, st->num);
- break;
- case TCP_SEQ_STATE_OPENREQ:
+ if (sk->sk_state == TCP_TIME_WAIT)
+ get_timewait4_sock(v, seq, st->num);
+ else if (sk->sk_state == TCP_NEW_SYN_RECV)
get_openreq4(v, seq, st->num);
- break;
- }
+ else
+ get_tcp4_sock(v, seq, st->num);
out:
seq_pad(seq, '\n');
return 0;