summaryrefslogtreecommitdiff
path: root/net/rds/tcp_listen.c
blob: c9c496844cd7ad3ac0e240e53ba6c5e1cf3aea7b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
/*
 * 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"

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;
}

/* rds_tcp_accept_one_path(): if accepting on cp_index > 0, make sure the
 * client's ipaddr < server's ipaddr. Otherwise, close the accepted
 * socket and force a reconneect from smaller -> larger ip addr. The reason
 * we special case cp_index 0 is to allow the rds probe ping itself to itself
 * get through efficiently.
 * Since reconnects are only initiated from the node with the numerically
 * smaller ip address, we recycle conns in RDS_CONN_ERROR on the passive side
 * by moving them to CONNECTING in this function.
 */
struct rds_tcp_connection *rds_tcp_accept_one_path(struct rds_connection *conn)
{
	int i;
	bool peer_is_smaller = (conn->c_faddr < conn->c_laddr);
	int npaths = conn->c_npaths;

	if (npaths <= 1) {
		struct rds_conn_path *cp = &conn->c_path[0];
		int ret;

		ret = rds_conn_path_transition(cp, RDS_CONN_DOWN,
					       RDS_CONN_CONNECTING);
		if (!ret)
			rds_conn_path_transition(cp, RDS_CONN_ERROR,
						 RDS_CONN_CONNECTING);
		return cp->cp_transport_data;
	}

	/* for mprds, paths with cp_index > 0 MUST be initiated by the peer
	 * with the smaller address.
	 */
	if (!peer_is_smaller)
		return NULL;

	for (i = 0; i < npaths; i++) {
		struct rds_conn_path *cp = &conn->c_path[i];

		if (rds_conn_path_transition(cp, RDS_CONN_DOWN,
					     RDS_CONN_CONNECTING) ||
		    rds_conn_path_transition(cp, RDS_CONN_ERROR,
					     RDS_CONN_CONNECTING)) {
			return cp->cp_transport_data;
		}
	}
	return NULL;
}

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 = NULL;
	int conn_state;
	struct rds_conn_path *cp;

	if (!sock) /* module unload or netns delete in progress */
		return -ENETUNREACH;

	ret = sock_create_kern(sock_net(sock->sk), 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(sock_net(sock->sk),
			       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.
	 *
	 * If the client reboots, this conn will need to be cleaned up.
	 * rds_tcp_state_change() will do that cleanup
	 */
	rs_tcp = rds_tcp_accept_one_path(conn);
	if (!rs_tcp)
		goto rst_nsk;
	mutex_lock(&rs_tcp->t_conn_path_lock);
	cp = rs_tcp->t_cpath;
	conn_state = rds_conn_path_state(cp);
	if (conn_state != RDS_CONN_CONNECTING && conn_state != RDS_CONN_UP &&
	    conn_state != RDS_CONN_ERROR)
		goto rst_nsk;
	if (rs_tcp->t_sock) {
		/* Need to resolve a duelling SYN between peers.
		 * We have an outstanding SYN to this peer, which may
		 * potentially have transitioned to the RDS_CONN_UP state,
		 * so we must quiesce any send threads before resetting
		 * c_transport_data.
		 */
		if (ntohl(inet->inet_saddr) < ntohl(inet->inet_daddr) ||
		    !cp->cp_outgoing) {
			goto rst_nsk;
		} else {
			rds_tcp_reset_callbacks(new_sock, cp);
			cp->cp_outgoing = 0;
			/* rds_connect_path_complete() marks RDS_CONN_UP */
			rds_connect_path_complete(cp, RDS_CONN_RESETTING);
		}
	} else {
		rds_tcp_set_callbacks(new_sock, cp);
		rds_connect_path_complete(cp, RDS_CONN_CONNECTING);
	}
	new_sock = NULL;
	ret = 0;
	goto out;
rst_nsk:
	/* reset the newly returned accept sock and bail */
	kernel_sock_shutdown(new_sock, SHUT_RDWR);
	ret = 0;
out:
	if (rs_tcp)
		mutex_unlock(&rs_tcp->t_conn_path_lock);
	if (new_sock)
		sock_release(new_sock);
	return ret;
}

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

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

	read_lock_bh(&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)
		rds_tcp_accept_work(sk);
	else
		ready = rds_tcp_listen_sock_def_readable(sock_net(sk));

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

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

	ret = sock_create_kern(net, 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;

	return sock;
out:
	if (sock)
		sock_release(sock);
	return NULL;
}

void rds_tcp_listen_stop(struct socket *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);
}