net/rds/tcp_listen.c - kernel/lockdown - Git at Google

 /*
  * Copyright (c) 2006 Oracle.  All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
  * General Public License (GPL) Version 2, available from the file
  * COPYING in the main directory of this source tree, or the
  * OpenIB.org BSD license below:
  *
  *     Redistribution and use in source and binary forms, with or
  *     without modification, are permitted provided that the following
  *     conditions are met:
  *
  *      - Redistributions of source code must retain the above
  *        copyright notice, this list of conditions and the following
  *        disclaimer.
  *
  *      - Redistributions in binary form must reproduce the above
  *        copyright notice, this list of conditions and the following
  *        disclaimer in the documentation and/or other materials
  *        provided with the distribution.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  *
  */
 #include <linux/kernel.h>
 #include <linux/gfp.h>
 #include <linux/in.h>
 #include <net/tcp.h>

 #include "rds.h"
 #include "tcp.h"

 /*
  * cheesy, but simple..
  */
 static void rds_tcp_accept_worker(struct work_struct *work);
 static DECLARE_WORK(rds_tcp_listen_work, rds_tcp_accept_worker);
 static struct socket *rds_tcp_listen_sock;

 static int rds_tcp_keepalive(struct socket *sock)
 {
 	/* values below based on xs_udp_default_timeout */
 	int keepidle = 5; /* send a probe 'keepidle' secs after last data */
 	int keepcnt = 5; /* number of unack'ed probes before declaring dead */
 	int keepalive = 1;
 	int ret = 0;

 	ret = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
 				(char *)&keepalive, sizeof(keepalive));
 	if (ret < 0)
 		goto bail;

 	ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPCNT,
 				(char *)&keepcnt, sizeof(keepcnt));
 	if (ret < 0)
 		goto bail;

 	ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPIDLE,
 				(char *)&keepidle, sizeof(keepidle));
 	if (ret < 0)
 		goto bail;

 	/* KEEPINTVL is the interval between successive probes. We follow
 	 * the model in xs_tcp_finish_connecting() and re-use keepidle.
 	 */
 	ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPINTVL,
 				(char *)&keepidle, sizeof(keepidle));
 bail:
 	return ret;
 }

 static int rds_tcp_accept_one(struct socket *sock)
 {
 	struct socket *new_sock = NULL;
 	struct rds_connection *conn;
 	int ret;
 	struct inet_sock *inet;
 	struct rds_tcp_connection *rs_tcp;

 	ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
 			       sock->sk->sk_protocol, &new_sock);
 	if (ret)
 		goto out;

 	new_sock->type = sock->type;
 	new_sock->ops = sock->ops;
 	ret = sock->ops->accept(sock, new_sock, O_NONBLOCK);
 	if (ret < 0)
 		goto out;

 	ret = rds_tcp_keepalive(new_sock);
 	if (ret < 0)
 		goto out;

 	rds_tcp_tune(new_sock);

 	inet = inet_sk(new_sock->sk);

 	rdsdebug("accepted tcp %pI4:%u -> %pI4:%u\n",
 		 &inet->inet_saddr, ntohs(inet->inet_sport),
 		 &inet->inet_daddr, ntohs(inet->inet_dport));

 	conn = rds_conn_create(inet->inet_saddr, inet->inet_daddr,
 			       &rds_tcp_transport, GFP_KERNEL);
 	if (IS_ERR(conn)) {
 		ret = PTR_ERR(conn);
 		goto out;
 	}
 	/* An incoming SYN request came in, and TCP just accepted it.
 	 * We always create a new conn for listen side of TCP, and do not
 	 * add it to the c_hash_list.
 	 *
 	 * If the client reboots, this conn will need to be cleaned up.
 	 * rds_tcp_state_change() will do that cleanup
 	 */
 	rs_tcp = (struct rds_tcp_connection *)conn->c_transport_data;
 	WARN_ON(!rs_tcp || rs_tcp->t_sock);

 	/*
 	 * see the comment above rds_queue_delayed_reconnect()
 	 */
 	if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_CONNECTING)) {
 		if (rds_conn_state(conn) == RDS_CONN_UP)
 			rds_tcp_stats_inc(s_tcp_listen_closed_stale);
 		else
 			rds_tcp_stats_inc(s_tcp_connect_raced);
 		rds_conn_drop(conn);
 		ret = 0;
 		goto out;
 	}

 	rds_tcp_set_callbacks(new_sock, conn);
 	rds_connect_complete(conn);
 	new_sock = NULL;
 	ret = 0;

 out:
 	if (new_sock)
 		sock_release(new_sock);
 	return ret;
 }

 static void rds_tcp_accept_worker(struct work_struct *work)
 {
 	while (rds_tcp_accept_one(rds_tcp_listen_sock) == 0)
 		cond_resched();
 }

 void rds_tcp_listen_data_ready(struct sock *sk)
 {
 	void (*ready)(struct sock *sk);

 	rdsdebug("listen data ready sk %p\n", sk);

 	read_lock(&sk->sk_callback_lock);
 	ready = sk->sk_user_data;
 	if (!ready) { /* check for teardown race */
 		ready = sk->sk_data_ready;
 		goto out;
 	}

 	/*
 	 * ->sk_data_ready is also called for a newly established child socket
 	 * before it has been accepted and the accepter has set up their
 	 * data_ready.. we only want to queue listen work for our listening
 	 * socket
 	 */
 	if (sk->sk_state == TCP_LISTEN)
 		queue_work(rds_wq, &rds_tcp_listen_work);

 out:
 	read_unlock(&sk->sk_callback_lock);
 	ready(sk);
 }

 int rds_tcp_listen_init(void)
 {
 	struct sockaddr_in sin;
 	struct socket *sock = NULL;
 	int ret;

 	ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
 	if (ret < 0)
 		goto out;

 	sock->sk->sk_reuse = SK_CAN_REUSE;
 	rds_tcp_nonagle(sock);

 	write_lock_bh(&sock->sk->sk_callback_lock);
 	sock->sk->sk_user_data = sock->sk->sk_data_ready;
 	sock->sk->sk_data_ready = rds_tcp_listen_data_ready;
 	write_unlock_bh(&sock->sk->sk_callback_lock);

 	sin.sin_family = PF_INET;
 	sin.sin_addr.s_addr = (__force u32)htonl(INADDR_ANY);
 	sin.sin_port = (__force u16)htons(RDS_TCP_PORT);

 	ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
 	if (ret < 0)
 		goto out;

 	ret = sock->ops->listen(sock, 64);
 	if (ret < 0)
 		goto out;

 	rds_tcp_listen_sock = sock;
 	sock = NULL;
 out:
 	if (sock)
 		sock_release(sock);
 	return ret;
 }

 void rds_tcp_listen_stop(void)
 {
 	struct socket *sock = rds_tcp_listen_sock;
 	struct sock *sk;

 	if (!sock)
 		return;

 	sk = sock->sk;

 	/* serialize with and prevent further callbacks */
 	lock_sock(sk);
 	write_lock_bh(&sk->sk_callback_lock);
 	if (sk->sk_user_data) {
 		sk->sk_data_ready = sk->sk_user_data;
 		sk->sk_user_data = NULL;
 	}
 	write_unlock_bh(&sk->sk_callback_lock);
 	release_sock(sk);

 	/* wait for accepts to stop and close the socket */
 	flush_workqueue(rds_wq);
 	sock_release(sock);
 	rds_tcp_listen_sock = NULL;
 }
	/*
	* Copyright (c) 2006 Oracle. All rights reserved.
	*
	* This software is available to you under a choice of one of two
	* licenses. You may choose to be licensed under the terms of the GNU
	* General Public License (GPL) Version 2, available from the file
	* COPYING in the main directory of this source tree, or the
	* OpenIB.org BSD license below:
	*
	* Redistribution and use in source and binary forms, with or
	* without modification, are permitted provided that the following
	* conditions are met:
	*
	* - Redistributions of source code must retain the above
	* copyright notice, this list of conditions and the following
	* disclaimer.
	*
	* - Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following
	* disclaimer in the documentation and/or other materials
	* provided with the distribution.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
	* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
	* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
	* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	* SOFTWARE.
	*
	*/
	#include <linux/kernel.h>
	#include <linux/gfp.h>
	#include <linux/in.h>
	#include <net/tcp.h>

	#include "rds.h"
	#include "tcp.h"

	/*
	* cheesy, but simple..
	*/
	static void rds_tcp_accept_worker(struct work_struct *work);
	static DECLARE_WORK(rds_tcp_listen_work, rds_tcp_accept_worker);
	static struct socket *rds_tcp_listen_sock;

	static int rds_tcp_keepalive(struct socket *sock)
	{
	/* values below based on xs_udp_default_timeout */
	int keepidle = 5; /* send a probe 'keepidle' secs after last data */
	int keepcnt = 5; /* number of unack'ed probes before declaring dead */
	int keepalive = 1;
	int ret = 0;

	ret = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
	(char *)&keepalive, sizeof(keepalive));
	if (ret < 0)
	goto bail;

	ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPCNT,
	(char *)&keepcnt, sizeof(keepcnt));
	if (ret < 0)
	goto bail;

	ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPIDLE,
	(char *)&keepidle, sizeof(keepidle));
	if (ret < 0)
	goto bail;

	/* KEEPINTVL is the interval between successive probes. We follow
	* the model in xs_tcp_finish_connecting() and re-use keepidle.
	*/
	ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPINTVL,
	(char *)&keepidle, sizeof(keepidle));
	bail:
	return ret;
	}

	static int rds_tcp_accept_one(struct socket *sock)
	{
	struct socket *new_sock = NULL;
	struct rds_connection *conn;
	int ret;
	struct inet_sock *inet;
	struct rds_tcp_connection *rs_tcp;

	ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
	sock->sk->sk_protocol, &new_sock);
	if (ret)
	goto out;

	new_sock->type = sock->type;
	new_sock->ops = sock->ops;
	ret = sock->ops->accept(sock, new_sock, O_NONBLOCK);
	if (ret < 0)
	goto out;

	ret = rds_tcp_keepalive(new_sock);
	if (ret < 0)
	goto out;

	rds_tcp_tune(new_sock);

	inet = inet_sk(new_sock->sk);

	rdsdebug("accepted tcp %pI4:%u -> %pI4:%u\n",
	&inet->inet_saddr, ntohs(inet->inet_sport),
	&inet->inet_daddr, ntohs(inet->inet_dport));

	conn = rds_conn_create(inet->inet_saddr, inet->inet_daddr,
	&rds_tcp_transport, GFP_KERNEL);
	if (IS_ERR(conn)) {
	ret = PTR_ERR(conn);
	goto out;
	}
	/* An incoming SYN request came in, and TCP just accepted it.
	* We always create a new conn for listen side of TCP, and do not
	* add it to the c_hash_list.
	*
	* If the client reboots, this conn will need to be cleaned up.
	* rds_tcp_state_change() will do that cleanup
	*/
	rs_tcp = (struct rds_tcp_connection *)conn->c_transport_data;
	WARN_ON(!rs_tcp \|\| rs_tcp->t_sock);

	/*
	* see the comment above rds_queue_delayed_reconnect()
	*/
	if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_CONNECTING)) {
	if (rds_conn_state(conn) == RDS_CONN_UP)
	rds_tcp_stats_inc(s_tcp_listen_closed_stale);
	else
	rds_tcp_stats_inc(s_tcp_connect_raced);
	rds_conn_drop(conn);
	ret = 0;
	goto out;
	}

	rds_tcp_set_callbacks(new_sock, conn);
	rds_connect_complete(conn);
	new_sock = NULL;
	ret = 0;

	out:
	if (new_sock)
	sock_release(new_sock);
	return ret;
	}

	static void rds_tcp_accept_worker(struct work_struct *work)
	{
	while (rds_tcp_accept_one(rds_tcp_listen_sock) == 0)
	cond_resched();
	}

	void rds_tcp_listen_data_ready(struct sock *sk)
	{
	void (ready)(struct sock sk);

	rdsdebug("listen data ready sk %p\n", sk);

	read_lock(&sk->sk_callback_lock);
	ready = sk->sk_user_data;
	if (!ready) { /* check for teardown race */
	ready = sk->sk_data_ready;
	goto out;
	}

	/*
	* ->sk_data_ready is also called for a newly established child socket
	* before it has been accepted and the accepter has set up their
	* data_ready.. we only want to queue listen work for our listening
	* socket
	*/
	if (sk->sk_state == TCP_LISTEN)
	queue_work(rds_wq, &rds_tcp_listen_work);

	out:
	read_unlock(&sk->sk_callback_lock);
	ready(sk);
	}

	int rds_tcp_listen_init(void)
	{
	struct sockaddr_in sin;
	struct socket *sock = NULL;
	int ret;

	ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
	if (ret < 0)
	goto out;

	sock->sk->sk_reuse = SK_CAN_REUSE;
	rds_tcp_nonagle(sock);

	write_lock_bh(&sock->sk->sk_callback_lock);
	sock->sk->sk_user_data = sock->sk->sk_data_ready;
	sock->sk->sk_data_ready = rds_tcp_listen_data_ready;
	write_unlock_bh(&sock->sk->sk_callback_lock);

	sin.sin_family = PF_INET;
	sin.sin_addr.s_addr = (__force u32)htonl(INADDR_ANY);
	sin.sin_port = (__force u16)htons(RDS_TCP_PORT);

	ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
	if (ret < 0)
	goto out;

	ret = sock->ops->listen(sock, 64);
	if (ret < 0)
	goto out;

	rds_tcp_listen_sock = sock;
	sock = NULL;
	out:
	if (sock)
	sock_release(sock);
	return ret;
	}

	void rds_tcp_listen_stop(void)
	{
	struct socket *sock = rds_tcp_listen_sock;
	struct sock *sk;

	if (!sock)
	return;

	sk = sock->sk;

	/* serialize with and prevent further callbacks */
	lock_sock(sk);
	write_lock_bh(&sk->sk_callback_lock);
	if (sk->sk_user_data) {
	sk->sk_data_ready = sk->sk_user_data;
	sk->sk_user_data = NULL;
	}
	write_unlock_bh(&sk->sk_callback_lock);
	release_sock(sk);

	/* wait for accepts to stop and close the socket */
	flush_workqueue(rds_wq);
	sock_release(sock);
	rds_tcp_listen_sock = NULL;
	}