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
41int rds_tcp_keepalive(struct socket *sock)
42{
43	/* values below based on xs_udp_default_timeout */
44	int keepidle = 5; /* send a probe 'keepidle' secs after last data */
45	int keepcnt = 5; /* number of unack'ed probes before declaring dead */
46	int keepalive = 1;
47	int ret = 0;
48
49	ret = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
50				(char *)&keepalive, sizeof(keepalive));
51	if (ret < 0)
52		goto bail;
53
54	ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPCNT,
55				(char *)&keepcnt, sizeof(keepcnt));
56	if (ret < 0)
57		goto bail;
58
59	ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPIDLE,
60				(char *)&keepidle, sizeof(keepidle));
61	if (ret < 0)
62		goto bail;
63
64	/* KEEPINTVL is the interval between successive probes. We follow
65	 * the model in xs_tcp_finish_connecting() and re-use keepidle.
66	 */
67	ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPINTVL,
68				(char *)&keepidle, sizeof(keepidle));
69bail:
70	return ret;
71}
72
73int rds_tcp_accept_one(struct socket *sock)
74{
75	struct socket *new_sock = NULL;
76	struct rds_connection *conn;
77	int ret;
78	struct inet_sock *inet;
79	struct rds_tcp_connection *rs_tcp;
80
81	ret = sock_create_kern(sock_net(sock->sk), sock->sk->sk_family,
82			       sock->sk->sk_type, sock->sk->sk_protocol,
83			       &new_sock);
84	if (ret)
85		goto out;
86
87	new_sock->type = sock->type;
88	new_sock->ops = sock->ops;
89	ret = sock->ops->accept(sock, new_sock, O_NONBLOCK);
90	if (ret < 0)
91		goto out;
92
93	ret = rds_tcp_keepalive(new_sock);
94	if (ret < 0)
95		goto out;
96
97	rds_tcp_tune(new_sock);
98
99	inet = inet_sk(new_sock->sk);
100
101	rdsdebug("accepted tcp %pI4:%u -> %pI4:%u\n",
102		 &inet->inet_saddr, ntohs(inet->inet_sport),
103		 &inet->inet_daddr, ntohs(inet->inet_dport));
104
105	conn = rds_conn_create(sock_net(sock->sk),
106			       inet->inet_saddr, inet->inet_daddr,
107			       &rds_tcp_transport, GFP_KERNEL);
108	if (IS_ERR(conn)) {
109		ret = PTR_ERR(conn);
110		goto out;
111	}
112	/* An incoming SYN request came in, and TCP just accepted it.
113	 *
114	 * If the client reboots, this conn will need to be cleaned up.
115	 * rds_tcp_state_change() will do that cleanup
116	 */
117	rs_tcp = (struct rds_tcp_connection *)conn->c_transport_data;
118	if (rs_tcp->t_sock &&
119	    ntohl(inet->inet_saddr) < ntohl(inet->inet_daddr)) {
120		struct sock *nsk = new_sock->sk;
121
122		nsk->sk_user_data = NULL;
123		nsk->sk_prot->disconnect(nsk, 0);
124		tcp_done(nsk);
125		new_sock = NULL;
126		ret = 0;
127		goto out;
128	} else if (rs_tcp->t_sock) {
129		rds_tcp_restore_callbacks(rs_tcp->t_sock, rs_tcp);
130		conn->c_outgoing = 0;
131	}
132
133	rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_CONNECTING);
134	rds_tcp_set_callbacks(new_sock, conn);
135	rds_connect_complete(conn);
136	new_sock = NULL;
137	ret = 0;
138
139out:
140	if (new_sock)
141		sock_release(new_sock);
142	return ret;
143}
144
145void rds_tcp_listen_data_ready(struct sock *sk)
146{
147	void (*ready)(struct sock *sk);
148
149	rdsdebug("listen data ready sk %p\n", sk);
150
151	read_lock(&sk->sk_callback_lock);
152	ready = sk->sk_user_data;
153	if (!ready) { /* check for teardown race */
154		ready = sk->sk_data_ready;
155		goto out;
156	}
157
158	/*
159	 * ->sk_data_ready is also called for a newly established child socket
160	 * before it has been accepted and the accepter has set up their
161	 * data_ready.. we only want to queue listen work for our listening
162	 * socket
163	 */
164	if (sk->sk_state == TCP_LISTEN)
165		rds_tcp_accept_work(sk);
166
167out:
168	read_unlock(&sk->sk_callback_lock);
169	ready(sk);
170}
171
172struct socket *rds_tcp_listen_init(struct net *net)
173{
174	struct sockaddr_in sin;
175	struct socket *sock = NULL;
176	int ret;
177
178	ret = sock_create_kern(net, PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
179	if (ret < 0)
180		goto out;
181
182	sock->sk->sk_reuse = SK_CAN_REUSE;
183	rds_tcp_nonagle(sock);
184
185	write_lock_bh(&sock->sk->sk_callback_lock);
186	sock->sk->sk_user_data = sock->sk->sk_data_ready;
187	sock->sk->sk_data_ready = rds_tcp_listen_data_ready;
188	write_unlock_bh(&sock->sk->sk_callback_lock);
189
190	sin.sin_family = PF_INET;
191	sin.sin_addr.s_addr = (__force u32)htonl(INADDR_ANY);
192	sin.sin_port = (__force u16)htons(RDS_TCP_PORT);
193
194	ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
195	if (ret < 0)
196		goto out;
197
198	ret = sock->ops->listen(sock, 64);
199	if (ret < 0)
200		goto out;
201
202	return sock;
203out:
204	if (sock)
205		sock_release(sock);
206	return NULL;
207}
208
209void rds_tcp_listen_stop(struct socket *sock)
210{
211	struct sock *sk;
212
213	if (!sock)
214		return;
215
216	sk = sock->sk;
217
218	/* serialize with and prevent further callbacks */
219	lock_sock(sk);
220	write_lock_bh(&sk->sk_callback_lock);
221	if (sk->sk_user_data) {
222		sk->sk_data_ready = sk->sk_user_data;
223		sk->sk_user_data = NULL;
224	}
225	write_unlock_bh(&sk->sk_callback_lock);
226	release_sock(sk);
227
228	/* wait for accepts to stop and close the socket */
229	flush_workqueue(rds_wq);
230	sock_release(sock);
231}
232