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Commit 900f65d3 authored by Neal Cardwell's avatar Neal Cardwell Committed by David S. Miller
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tcp: move duplicate code from tcp_v4_init_sock()/tcp_v6_init_sock() 



This commit moves the (substantial) common code shared between
tcp_v4_init_sock() and tcp_v6_init_sock() to a new address-family
independent function, tcp_init_sock().

Centralizing this functionality should help avoid drift issues,
e.g. where the IPv4 side is updated without a corresponding update to
IPv6. There was already some drift: IPv4 initialized snd_cwnd to
TCP_INIT_CWND, while the IPv6 side was still initializing snd_cwnd to
2 (in this case it should not matter, since snd_cwnd is also
initialized in tcp_init_metrics(), but the general risks and
maintenance overhead remain).

When diffing the old and new code, note that new tcp_init_sock()
function uses the order of steps from the tcp_v4_init_sock()
implementation (the order is slightly different in
tcp_v6_init_sock()).

Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e66e9a31

include/net/tcp.h

+1 −0
Original line number Diff line number Diff line
@@ -395,6 +395,7 @@ extern void tcp_enter_loss(struct sock *sk, int how); 
extern void tcp_clear_retrans(struct tcp_sock *tp);

extern void tcp_update_metrics(struct sock *sk);

extern void tcp_close(struct sock *sk, long timeout);

extern void tcp_init_sock(struct sock *sk);

extern unsigned int tcp_poll(struct file * file, struct socket *sock,

			     struct poll_table_struct *wait);

extern int tcp_getsockopt(struct sock *sk, int level, int optname,

net/ipv4/tcp.c

+64 −0
Original line number Diff line number Diff line
@@ -363,6 +363,70 @@ static int retrans_to_secs(u8 retrans, int timeout, int rto_max) 
	return period;

}



/* Address-family independent initialization for a tcp_sock.

 *

 * NOTE: A lot of things set to zero explicitly by call to

 *       sk_alloc() so need not be done here.

 */

void tcp_init_sock(struct sock *sk)

{

	struct inet_connection_sock *icsk = inet_csk(sk);

	struct tcp_sock *tp = tcp_sk(sk);



	skb_queue_head_init(&tp->out_of_order_queue);

	tcp_init_xmit_timers(sk);

	tcp_prequeue_init(tp);



	icsk->icsk_rto = TCP_TIMEOUT_INIT;

	tp->mdev = TCP_TIMEOUT_INIT;



	/* So many TCP implementations out there (incorrectly) count the

	 * initial SYN frame in their delayed-ACK and congestion control

	 * algorithms that we must have the following bandaid to talk

	 * efficiently to them.  -DaveM

	 */

	tp->snd_cwnd = TCP_INIT_CWND;



	/* See draft-stevens-tcpca-spec-01 for discussion of the

	 * initialization of these values.

	 */

	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;

	tp->snd_cwnd_clamp = ~0;

	tp->mss_cache = TCP_MSS_DEFAULT;



	tp->reordering = sysctl_tcp_reordering;

	icsk->icsk_ca_ops = &tcp_init_congestion_ops;



	sk->sk_state = TCP_CLOSE;



	sk->sk_write_space = sk_stream_write_space;

	sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);



	icsk->icsk_sync_mss = tcp_sync_mss;



	/* TCP Cookie Transactions */

	if (sysctl_tcp_cookie_size > 0) {

		/* Default, cookies without s_data_payload. */

		tp->cookie_values =

			kzalloc(sizeof(*tp->cookie_values),

				sk->sk_allocation);

		if (tp->cookie_values != NULL)

			kref_init(&tp->cookie_values->kref);

	}

	/* Presumed zeroed, in order of appearance:

	 *	cookie_in_always, cookie_out_never,

	 *	s_data_constant, s_data_in, s_data_out

	 */

	sk->sk_sndbuf = sysctl_tcp_wmem[1];

	sk->sk_rcvbuf = sysctl_tcp_rmem[1];



	local_bh_disable();

	sock_update_memcg(sk);

	sk_sockets_allocated_inc(sk);

	local_bh_enable();

}

EXPORT_SYMBOL(tcp_init_sock);



/*

 *	Wait for a TCP event.

 *

net/ipv4/tcp_ipv4.c

+2 −50
Original line number Diff line number Diff line
@@ -1890,62 +1890,14 @@ static int tcp_v4_init_sock(struct sock *sk) 
	struct inet_connection_sock *icsk = inet_csk(sk);

	struct tcp_sock *tp = tcp_sk(sk);



	skb_queue_head_init(&tp->out_of_order_queue);

	tcp_init_xmit_timers(sk);

	tcp_prequeue_init(tp);



	icsk->icsk_rto = TCP_TIMEOUT_INIT;

	tp->mdev = TCP_TIMEOUT_INIT;



	/* So many TCP implementations out there (incorrectly) count the

	 * initial SYN frame in their delayed-ACK and congestion control

	 * algorithms that we must have the following bandaid to talk

	 * efficiently to them.  -DaveM

	 */

	tp->snd_cwnd = TCP_INIT_CWND;



	/* See draft-stevens-tcpca-spec-01 for discussion of the

	 * initialization of these values.

	 */

	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;

	tp->snd_cwnd_clamp = ~0;

	tp->mss_cache = TCP_MSS_DEFAULT;



	tp->reordering = sysctl_tcp_reordering;

	icsk->icsk_ca_ops = &tcp_init_congestion_ops;



	sk->sk_state = TCP_CLOSE;



	sk->sk_write_space = sk_stream_write_space;

	sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);

	tcp_init_sock(sk);



	icsk->icsk_af_ops = &ipv4_specific;

	icsk->icsk_sync_mss = tcp_sync_mss;



#ifdef CONFIG_TCP_MD5SIG

	tp->af_specific = &tcp_sock_ipv4_specific;

#endif



	/* TCP Cookie Transactions */

	if (sysctl_tcp_cookie_size > 0) {

		/* Default, cookies without s_data_payload. */

		tp->cookie_values =

			kzalloc(sizeof(*tp->cookie_values),

				sk->sk_allocation);

		if (tp->cookie_values != NULL)

			kref_init(&tp->cookie_values->kref);

	}

	/* Presumed zeroed, in order of appearance:

	 *	cookie_in_always, cookie_out_never,

	 *	s_data_constant, s_data_in, s_data_out

	 */

	sk->sk_sndbuf = sysctl_tcp_wmem[1];

	sk->sk_rcvbuf = sysctl_tcp_rmem[1];



	local_bh_disable();

	sock_update_memcg(sk);

	sk_sockets_allocated_inc(sk);

	local_bh_enable();



	return 0;

}

net/ipv6/tcp_ipv6.c

+1 −49
Original line number Diff line number Diff line
@@ -1831,62 +1831,14 @@ static int tcp_v6_init_sock(struct sock *sk) 
	struct inet_connection_sock *icsk = inet_csk(sk);

	struct tcp_sock *tp = tcp_sk(sk);



	skb_queue_head_init(&tp->out_of_order_queue);

	tcp_init_xmit_timers(sk);

	tcp_prequeue_init(tp);



	icsk->icsk_rto = TCP_TIMEOUT_INIT;

	tp->mdev = TCP_TIMEOUT_INIT;



	/* So many TCP implementations out there (incorrectly) count the

	 * initial SYN frame in their delayed-ACK and congestion control

	 * algorithms that we must have the following bandaid to talk

	 * efficiently to them.  -DaveM

	 */

	tp->snd_cwnd = 2;



	/* See draft-stevens-tcpca-spec-01 for discussion of the

	 * initialization of these values.

	 */

	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;

	tp->snd_cwnd_clamp = ~0;

	tp->mss_cache = TCP_MSS_DEFAULT;



	tp->reordering = sysctl_tcp_reordering;



	sk->sk_state = TCP_CLOSE;

	tcp_init_sock(sk);



	icsk->icsk_af_ops = &ipv6_specific;

	icsk->icsk_ca_ops = &tcp_init_congestion_ops;

	icsk->icsk_sync_mss = tcp_sync_mss;

	sk->sk_write_space = sk_stream_write_space;

	sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);



#ifdef CONFIG_TCP_MD5SIG

	tp->af_specific = &tcp_sock_ipv6_specific;

#endif



	/* TCP Cookie Transactions */

	if (sysctl_tcp_cookie_size > 0) {

		/* Default, cookies without s_data_payload. */

		tp->cookie_values =

			kzalloc(sizeof(*tp->cookie_values),

				sk->sk_allocation);

		if (tp->cookie_values != NULL)

			kref_init(&tp->cookie_values->kref);

	}

	/* Presumed zeroed, in order of appearance:

	 *	cookie_in_always, cookie_out_never,

	 *	s_data_constant, s_data_in, s_data_out

	 */

	sk->sk_sndbuf = sysctl_tcp_wmem[1];

	sk->sk_rcvbuf = sysctl_tcp_rmem[1];



	local_bh_disable();

	sock_update_memcg(sk);

	sk_sockets_allocated_inc(sk);

	local_bh_enable();



	return 0;

}