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 */
44 static void rds_tcp_accept_worker(struct work_struct *work);
45 static DECLARE_WORK(rds_tcp_listen_work, rds_tcp_accept_worker);
46 static struct socket *rds_tcp_listen_sock;
47
rds_tcp_accept_one(struct socket * sock)48 static 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
99 out:
100 if (new_sock)
101 sock_release(new_sock);
102 return ret;
103 }
104
rds_tcp_accept_worker(struct work_struct * work)105 static 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
rds_tcp_listen_data_ready(struct sock * sk,int bytes)111 void 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) { /* 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
133 out:
134 read_unlock_bh(&sk->sk_callback_lock);
135 ready(sk, bytes);
136 }
137
rds_tcp_listen_init(void)138 int 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;
170 out:
171 if (sock)
172 sock_release(sock);
173 return ret;
174 }
175
rds_tcp_listen_stop(void)176 void rds_tcp_listen_stop(void)
177 {
178 struct socket *sock = rds_tcp_listen_sock;
179 struct sock *sk;
180
181 if (!sock)
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