Commit 5903123f authored by Akhmat Karakotov's avatar Akhmat Karakotov Committed by David S. Miller
Browse files

tcp: Use BPF timeout setting for SYN ACK RTO 



When setting RTO through BPF program, some SYN ACK packets were unaffected
and continued to use TCP_TIMEOUT_INIT constant. This patch adds timeout
option to struct request_sock. Option is initialized with TCP_TIMEOUT_INIT
and is reassigned through BPF using tcp_timeout_init call. SYN ACK
retransmits now use newly added timeout option.

Signed-off-by: default avatarAkhmat Karakotov <hmukos@yandex-team.ru>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>

v2:
	- Add timeout option to struct request_sock. Do not call
	  tcp_timeout_init on every syn ack retransmit.

v3:
	- Use unsigned long for min. Bound tcp_timeout_init to TCP_RTO_MAX.

v4:
	- Refactor duplicate code by adding reqsk_timeout function.
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0b6b0d31

include/net/inet_connection_sock.h

+8 −0
Original line number Diff line number Diff line
@@ -285,6 +285,14 @@ static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk) 
bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);

void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);



static inline unsigned long

reqsk_timeout(struct request_sock *req, unsigned long max_timeout)

{

	u64 timeout = (u64)req->timeout << req->num_timeout;



	return (unsigned long)min_t(u64, timeout, max_timeout);

}



static inline void inet_csk_prepare_for_destroy_sock(struct sock *sk)

{

	/* The below has to be done to allow calling inet_csk_destroy_sock */

include/net/request_sock.h

+2 −0
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ struct request_sock { 
	struct saved_syn		*saved_syn;

	u32				secid;

	u32				peer_secid;

	u32				timeout;

};



static inline struct request_sock *inet_reqsk(const struct sock *sk)
@@ -104,6 +105,7 @@ reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener, 
	sk_node_init(&req_to_sk(req)->sk_node);

	sk_tx_queue_clear(req_to_sk(req));

	req->saved_syn = NULL;

	req->timeout = 0;

	req->num_timeout = 0;

	req->num_retrans = 0;

	req->sk = NULL;

include/net/tcp.h

+1 −1
Original line number Diff line number Diff line
@@ -2358,7 +2358,7 @@ static inline u32 tcp_timeout_init(struct sock *sk) 


	if (timeout <= 0)

		timeout = TCP_TIMEOUT_INIT;

	return timeout;

	return min_t(int, timeout, TCP_RTO_MAX);

}



static inline u32 tcp_rwnd_init_bpf(struct sock *sk)

net/ipv4/inet_connection_sock.c

+1 −4
Original line number Diff line number Diff line
@@ -866,12 +866,9 @@ static void reqsk_timer_handler(struct timer_list *t) 
	    (!resend ||

	     !inet_rtx_syn_ack(sk_listener, req) ||

	     inet_rsk(req)->acked)) {

		unsigned long timeo;



		if (req->num_timeout++ == 0)

			atomic_dec(&queue->young);

		timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);

		mod_timer(&req->rsk_timer, jiffies + timeo);

		mod_timer(&req->rsk_timer, jiffies + reqsk_timeout(req, TCP_RTO_MAX));



		if (!nreq)

			return;

net/ipv4/tcp_input.c

+5 −3
Original line number Diff line number Diff line
@@ -6723,6 +6723,7 @@ struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops, 
		ireq->ireq_state = TCP_NEW_SYN_RECV;

		write_pnet(&ireq->ireq_net, sock_net(sk_listener));

		ireq->ireq_family = sk_listener->sk_family;

		req->timeout = TCP_TIMEOUT_INIT;

	}



	return req;
@@ -6939,9 +6940,10 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, 
		sock_put(fastopen_sk);

	} else {

		tcp_rsk(req)->tfo_listener = false;

		if (!want_cookie)

			inet_csk_reqsk_queue_hash_add(sk, req,

				tcp_timeout_init((struct sock *)req));

		if (!want_cookie) {

			req->timeout = tcp_timeout_init((struct sock *)req);

			inet_csk_reqsk_queue_hash_add(sk, req, req->timeout);

		}

		af_ops->send_synack(sk, dst, &fl, req, &foc,

				    !want_cookie ? TCP_SYNACK_NORMAL :

						   TCP_SYNACK_COOKIE,