1/*
2 * Copyright (c) 2006 Oracle.  All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses.  You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 *     Redistribution and use in source and binary forms, with or
11 *     without modification, are permitted provided that the following
12 *     conditions are met:
13 *
14 *      - Redistributions of source code must retain the above
15 *        copyright notice, this list of conditions and the following
16 *        disclaimer.
17 *
18 *      - Redistributions in binary form must reproduce the above
19 *        copyright notice, this list of conditions and the following
20 *        disclaimer in the documentation and/or other materials
21 *        provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33#include <linux/kernel.h>
34#include <linux/gfp.h>
35#include <linux/in.h>
36#include <net/tcp.h>
37
38#include "rds.h"
39#include "tcp.h"
40
41/*
42 * cheesy, but simple..
43 */
44static void rds_tcp_accept_worker(struct work_struct *work);
45static DECLARE_WORK(rds_tcp_listen_work, rds_tcp_accept_worker);
46static struct socket *rds_tcp_listen_sock;
47
48static int rds_tcp_accept_one(struct socket *sock)
49{
50	struct socket *new_sock = NULL;
51	struct rds_connection *conn;
52	int ret;
53	struct inet_sock *inet;
54
55	ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
56			       sock->sk->sk_protocol, &new_sock);
57	if (ret)
58		goto out;
59
60	new_sock->type = sock->type;
61	new_sock->ops = sock->ops;
62	ret = sock->ops->accept(sock, new_sock, O_NONBLOCK);
63	if (ret < 0)
64		goto out;
65
66	rds_tcp_tune(new_sock);
67
68	inet = inet_sk(new_sock->sk);
69
70	rdsdebug("accepted tcp %pI4:%u -> %pI4:%u\n",
71		 &inet->inet_saddr, ntohs(inet->inet_sport),
72		 &inet->inet_daddr, ntohs(inet->inet_dport));
73
74	conn = rds_conn_create(inet->inet_saddr, inet->inet_daddr,
75			       &rds_tcp_transport, GFP_KERNEL);
76	if (IS_ERR(conn)) {
77		ret = PTR_ERR(conn);
78		goto out;
79	}
80
81	/*
82	 * see the comment above rds_queue_delayed_reconnect()
83	 */
84	if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_CONNECTING)) {
85		if (rds_conn_state(conn) == RDS_CONN_UP)
86			rds_tcp_stats_inc(s_tcp_listen_closed_stale);
87		else
88			rds_tcp_stats_inc(s_tcp_connect_raced);
89		rds_conn_drop(conn);
90		ret = 0;
91		goto out;
92	}
93
94	rds_tcp_set_callbacks(new_sock, conn);
95	rds_connect_complete(conn);
96	new_sock = NULL;
97	ret = 0;
98
99out:
100	if (new_sock)
101		sock_release(new_sock);
102	return ret;
103}
104
105static void rds_tcp_accept_worker(struct work_struct *work)
106{
107	while (rds_tcp_accept_one(rds_tcp_listen_sock) == 0)
108		cond_resched();
109}
110
111void rds_tcp_listen_data_ready(struct sock *sk, int bytes)
112{
113	void (*ready)(struct sock *sk, int bytes);
114
115	rdsdebug("listen data ready sk %p\n", sk);
116
117	read_lock_bh(&sk->sk_callback_lock);
118	ready = sk->sk_user_data;
119	if (ready == NULL) { /* check for teardown race */
120		ready = sk->sk_data_ready;
121		goto out;
122	}
123
124	/*
125	 * ->sk_data_ready is also called for a newly established child socket
126	 * before it has been accepted and the accepter has set up their
127	 * data_ready.. we only want to queue listen work for our listening
128	 * socket
129	 */
130	if (sk->sk_state == TCP_LISTEN)
131		queue_work(rds_wq, &rds_tcp_listen_work);
132
133out:
134	read_unlock_bh(&sk->sk_callback_lock);
135	ready(sk, bytes);
136}
137
138int __init rds_tcp_listen_init(void)
139{
140	struct sockaddr_in sin;
141	struct socket *sock = NULL;
142	int ret;
143
144	ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
145	if (ret < 0)
146		goto out;
147
148	sock->sk->sk_reuse = 1;
149	rds_tcp_nonagle(sock);
150
151	write_lock_bh(&sock->sk->sk_callback_lock);
152	sock->sk->sk_user_data = sock->sk->sk_data_ready;
153	sock->sk->sk_data_ready = rds_tcp_listen_data_ready;
154	write_unlock_bh(&sock->sk->sk_callback_lock);
155
156	sin.sin_family = PF_INET,
157	sin.sin_addr.s_addr = (__force u32)htonl(INADDR_ANY);
158	sin.sin_port = (__force u16)htons(RDS_TCP_PORT);
159
160	ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
161	if (ret < 0)
162		goto out;
163
164	ret = sock->ops->listen(sock, 64);
165	if (ret < 0)
166		goto out;
167
168	rds_tcp_listen_sock = sock;
169	sock = NULL;
170out:
171	if (sock)
172		sock_release(sock);
173	return ret;
174}
175
176void rds_tcp_listen_stop(void)
177{
178	struct socket *sock = rds_tcp_listen_sock;
179	struct sock *sk;
180
181	if (sock == NULL)
182		return;
183
184	sk = sock->sk;
185
186	/* serialize with and prevent further callbacks */
187	lock_sock(sk);
188	write_lock_bh(&sk->sk_callback_lock);
189	if (sk->sk_user_data) {
190		sk->sk_data_ready = sk->sk_user_data;
191		sk->sk_user_data = NULL;
192	}
193	write_unlock_bh(&sk->sk_callback_lock);
194	release_sock(sk);
195
196	/* wait for accepts to stop and close the socket */
197	flush_workqueue(rds_wq);
198	sock_release(sock);
199	rds_tcp_listen_sock = NULL;
200}
201