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Commit 72659ecc authored by Octavian Purdila's avatar Octavian Purdila Committed by David S. Miller
Browse files

tcp: account SYN-ACK timeouts & retransmissions 



Currently we don't increment SYN-ACK timeouts & retransmissions
although we do increment the same stats for SYN. We seem to have lost
the SYN-ACK accounting with the introduction of tcp_syn_recv_timer
(commit 2248761e in the netdev-vger-cvs tree).

This patch fixes this issue. In the process we also rename the v4/v6
syn/ack retransmit functions for clarity. We also add a new
request_socket operations (syn_ack_timeout) so we can keep code in
inet_connection_sock.c protocol agnostic.

Signed-off-by: default avatarOctavian Purdila <opurdila@ixiacom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0ec00f03

include/net/request_sock.h

+2 −0
Original line number Diff line number Diff line
@@ -45,6 +45,8 @@ struct request_sock_ops { 
	void		(*send_reset)(struct sock *sk,

				      struct sk_buff *skb);

	void		(*destructor)(struct request_sock *req);

	void		(*syn_ack_timeout)(struct sock *sk,

					   struct request_sock *req);

};



/* struct request_sock - mini sock to represent a connection request

include/net/tcp.h

+2 −0
Original line number Diff line number Diff line
@@ -400,6 +400,8 @@ extern int compat_tcp_setsockopt(struct sock *sk, 
					int level, int optname,

					char __user *optval, unsigned int optlen);

extern void			tcp_set_keepalive(struct sock *sk, int val);

extern void			tcp_syn_ack_timeout(struct sock *sk,

						    struct request_sock *req);

extern int			tcp_recvmsg(struct kiocb *iocb, struct sock *sk,

					    struct msghdr *msg,

					    size_t len, int nonblock,

net/ipv4/inet_connection_sock.c

+2 −0
Original line number Diff line number Diff line
@@ -529,6 +529,8 @@ void inet_csk_reqsk_queue_prune(struct sock *parent, 
				syn_ack_recalc(req, thresh, max_retries,

					       queue->rskq_defer_accept,

					       &expire, &resend);

				if (req->rsk_ops->syn_ack_timeout)

					req->rsk_ops->syn_ack_timeout(parent, req);

				if (!expire &&

				    (!resend ||

				     !req->rsk_ops->rtx_syn_ack(parent, req, NULL) ||

net/ipv4/tcp_ipv4.c

+10 −8
Original line number Diff line number Diff line
@@ -742,7 +742,7 @@ static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, 
 *	This still operates on a request_sock only, not on a big

 *	socket.

 */

static int __tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,

static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,

			      struct request_sock *req,

			      struct request_values *rvp)

{
@@ -775,10 +775,11 @@ static int __tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst, 
	return err;

}



static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req,

static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,

			      struct request_values *rvp)

{

	return __tcp_v4_send_synack(sk, NULL, req, rvp);

	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);

	return tcp_v4_send_synack(sk, NULL, req, rvp);

}



/*
@@ -1192,10 +1193,11 @@ static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb) 
struct request_sock_ops tcp_request_sock_ops __read_mostly = {

	.family		=	PF_INET,

	.obj_size	=	sizeof(struct tcp_request_sock),

	.rtx_syn_ack	=	tcp_v4_send_synack,

	.rtx_syn_ack	=	tcp_v4_rtx_synack,

	.send_ack	=	tcp_v4_reqsk_send_ack,

	.destructor	=	tcp_v4_reqsk_destructor,

	.send_reset	=	tcp_v4_send_reset,

	.syn_ack_timeout = 	tcp_syn_ack_timeout,

};



#ifdef CONFIG_TCP_MD5SIG
@@ -1373,7 +1375,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) 
	}

	tcp_rsk(req)->snt_isn = isn;



	if (__tcp_v4_send_synack(sk, dst, req,

	if (tcp_v4_send_synack(sk, dst, req,

			       (struct request_values *)&tmp_ext) ||

	    want_cookie)

		goto drop_and_free;

net/ipv4/tcp_timer.c

+6 −0
Original line number Diff line number Diff line
@@ -474,6 +474,12 @@ static void tcp_synack_timer(struct sock *sk) 
				   TCP_TIMEOUT_INIT, TCP_RTO_MAX);

}



void tcp_syn_ack_timeout(struct sock *sk, struct request_sock *req)

{

	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPTIMEOUTS);

}

EXPORT_SYMBOL(tcp_syn_ack_timeout);



void tcp_set_keepalive(struct sock *sk, int val)

{

	if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))