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tcp/dccp: install syn_recv requests into ehash table

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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>
This commit is contained in:
Eric Dumazet
2015-10-02 11:43:32 -07:00
committed by David S. Miller
parent 2feda34192
commit 079096f103
15 changed files with 163 additions and 504 deletions
Download Patch File Download Diff File Expand all files Collapse all files

84
net/ipv6/tcp_ipv6.c
View File

@@ -727,7 +727,6 @@ static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
.route_req = tcp_v6_route_req,
.init_seq = tcp_v6_init_sequence,
.send_synack = tcp_v6_send_synack,
.queue_hash_add = inet6_csk_reqsk_queue_hash_add,
};
static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
@@ -938,37 +937,11 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
}
static struct sock *tcp_v6_hnd_req(struct sock *sk, struct sk_buff *skb)
static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
{
const struct tcphdr *th = tcp_hdr(skb);
struct request_sock *req;
struct sock *nsk;
/* Find possible connection requests. */
req = inet6_csk_search_req(sk, th->source,
&ipv6_hdr(skb)->saddr,
&ipv6_hdr(skb)->daddr, tcp_v6_iif(skb));
if (req) {
nsk = tcp_check_req(sk, skb, req, false);
if (!nsk || nsk == sk)
reqsk_put(req);
return nsk;
}
nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo,
&ipv6_hdr(skb)->saddr, th->source,
&ipv6_hdr(skb)->daddr, ntohs(th->dest),
tcp_v6_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_v6_check(sk, skb);
#endif
@@ -1258,15 +1231,11 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
goto csum_err;
if (sk->sk_state == TCP_LISTEN) {
struct sock *nsk = tcp_v6_hnd_req(sk, skb);
struct sock *nsk = tcp_v6_cookie_check(sk, skb);
if (!nsk)
goto discard;
/*
* Queue it on the new socket if the new socket is active,
* otherwise we just shortcircuit this and continue with
* the new socket..
*/
if (nsk != sk) {
sock_rps_save_rxhash(nsk, skb);
sk_mark_napi_id(nsk, skb);
@@ -1402,6 +1371,33 @@ process:
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;
tcp_v6_fill_cb(skb, hdr, th);
if (tcp_v6_inbound_md5_hash(sk, skb)) {
reqsk_put(req);
goto discard_it;
}
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);
tcp_v6_restore_cb(skb);
} else if (tcp_child_process(sk, nsk, skb)) {
tcp_v6_send_reset(nsk, skb);
goto discard_it;
} else {
return 0;
}
}
if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
goto discard_and_relse;
@@ -1765,18 +1761,12 @@ static int tcp6_seq_show(struct seq_file *seq, void *v)
}
st = seq->private;
switch (st->state) {
case TCP_SEQ_STATE_LISTENING:
case TCP_SEQ_STATE_ESTABLISHED:
if (sk->sk_state == TCP_TIME_WAIT)
get_timewait6_sock(seq, v, st->num);
else
get_tcp6_sock(seq, v, st->num);
break;
case TCP_SEQ_STATE_OPENREQ:
if (sk->sk_state == TCP_TIME_WAIT)
get_timewait6_sock(seq, v, st->num);
else if (sk->sk_state == TCP_NEW_SYN_RECV)
get_openreq6(seq, v, st->num);
break;
}
else
get_tcp6_sock(seq, v, st->num);
out:
return 0;
}