1/*
2 * Copyright (c) 2006, 2017 Oracle and/or its affiliates. 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/in.h>
35#include <net/tcp.h>
36
37#include "rds.h"
38#include "tcp.h"
39
40void rds_tcp_state_change(struct sock *sk)
41{
42	void (*state_change)(struct sock *sk);
43	struct rds_conn_path *cp;
44	struct rds_tcp_connection *tc;
45
46	read_lock_bh(&sk->sk_callback_lock);
47	cp = sk->sk_user_data;
48	if (!cp) {
49		state_change = sk->sk_state_change;
50		goto out;
51	}
52	tc = cp->cp_transport_data;
53	state_change = tc->t_orig_state_change;
54
55	rdsdebug("sock %p state_change to %d\n", tc->t_sock, sk->sk_state);
56
57	switch (sk->sk_state) {
58	/* ignore connecting sockets as they make progress */
59	case TCP_SYN_SENT:
60	case TCP_SYN_RECV:
61		break;
62	case TCP_ESTABLISHED:
63		/* Force the peer to reconnect so that we have the
64		 * TCP ports going from <smaller-ip>.<transient> to
65		 * <larger-ip>.<RDS_TCP_PORT>. We avoid marking the
66		 * RDS connection as RDS_CONN_UP until the reconnect,
67		 * to avoid RDS datagram loss.
68		 */
69		if (rds_addr_cmp(&cp->cp_conn->c_laddr,
70				 &cp->cp_conn->c_faddr) >= 0 &&
71		    rds_conn_path_transition(cp, RDS_CONN_CONNECTING,
72					     RDS_CONN_ERROR)) {
73			rds_conn_path_drop(cp, false);
74		} else {
75			rds_connect_path_complete(cp, RDS_CONN_CONNECTING);
76		}
77		break;
78	case TCP_CLOSE_WAIT:
79	case TCP_CLOSE:
80		rds_conn_path_drop(cp, false);
81		break;
82	default:
83		break;
84	}
85out:
86	read_unlock_bh(&sk->sk_callback_lock);
87	state_change(sk);
88}
89
90int rds_tcp_conn_path_connect(struct rds_conn_path *cp)
91{
92	struct socket *sock = NULL;
93	struct sockaddr_in6 sin6;
94	struct sockaddr_in sin;
95	struct sockaddr *addr;
96	int addrlen;
97	bool isv6;
98	int ret;
99	struct rds_connection *conn = cp->cp_conn;
100	struct rds_tcp_connection *tc = cp->cp_transport_data;
101
102	/* for multipath rds,we only trigger the connection after
103	 * the handshake probe has determined the number of paths.
104	 */
105	if (cp->cp_index > 0 && cp->cp_conn->c_npaths < 2)
106		return -EAGAIN;
107
108	mutex_lock(&tc->t_conn_path_lock);
109
110	if (rds_conn_path_up(cp)) {
111		mutex_unlock(&tc->t_conn_path_lock);
112		return 0;
113	}
114	if (ipv6_addr_v4mapped(&conn->c_laddr)) {
115		ret = sock_create_kern(rds_conn_net(conn), PF_INET,
116				       SOCK_STREAM, IPPROTO_TCP, &sock);
117		isv6 = false;
118	} else {
119		ret = sock_create_kern(rds_conn_net(conn), PF_INET6,
120				       SOCK_STREAM, IPPROTO_TCP, &sock);
121		isv6 = true;
122	}
123
124	if (ret < 0)
125		goto out;
126
127	if (!rds_tcp_tune(sock)) {
128		ret = -EINVAL;
129		goto out;
130	}
131
132	if (isv6) {
133		sin6.sin6_family = AF_INET6;
134		sin6.sin6_addr = conn->c_laddr;
135		sin6.sin6_port = 0;
136		sin6.sin6_flowinfo = 0;
137		sin6.sin6_scope_id = conn->c_dev_if;
138		addr = (struct sockaddr *)&sin6;
139		addrlen = sizeof(sin6);
140	} else {
141		sin.sin_family = AF_INET;
142		sin.sin_addr.s_addr = conn->c_laddr.s6_addr32[3];
143		sin.sin_port = 0;
144		addr = (struct sockaddr *)&sin;
145		addrlen = sizeof(sin);
146	}
147
148	ret = kernel_bind(sock, addr, addrlen);
149	if (ret) {
150		rdsdebug("bind failed with %d at address %pI6c\n",
151			 ret, &conn->c_laddr);
152		goto out;
153	}
154
155	if (isv6) {
156		sin6.sin6_family = AF_INET6;
157		sin6.sin6_addr = conn->c_faddr;
158		sin6.sin6_port = htons(RDS_TCP_PORT);
159		sin6.sin6_flowinfo = 0;
160		sin6.sin6_scope_id = conn->c_dev_if;
161		addr = (struct sockaddr *)&sin6;
162		addrlen = sizeof(sin6);
163	} else {
164		sin.sin_family = AF_INET;
165		sin.sin_addr.s_addr = conn->c_faddr.s6_addr32[3];
166		sin.sin_port = htons(RDS_TCP_PORT);
167		addr = (struct sockaddr *)&sin;
168		addrlen = sizeof(sin);
169	}
170
171	/*
172	 * once we call connect() we can start getting callbacks and they
173	 * own the socket
174	 */
175	rds_tcp_set_callbacks(sock, cp);
176	ret = kernel_connect(sock, addr, addrlen, O_NONBLOCK);
177
178	rdsdebug("connect to address %pI6c returned %d\n", &conn->c_faddr, ret);
179	if (ret == -EINPROGRESS)
180		ret = 0;
181	if (ret == 0) {
182		rds_tcp_keepalive(sock);
183		sock = NULL;
184	} else {
185		rds_tcp_restore_callbacks(sock, cp->cp_transport_data);
186	}
187
188out:
189	mutex_unlock(&tc->t_conn_path_lock);
190	if (sock)
191		sock_release(sock);
192	return ret;
193}
194
195/*
196 * Before killing the tcp socket this needs to serialize with callbacks.  The
197 * caller has already grabbed the sending sem so we're serialized with other
198 * senders.
199 *
200 * TCP calls the callbacks with the sock lock so we hold it while we reset the
201 * callbacks to those set by TCP.  Our callbacks won't execute again once we
202 * hold the sock lock.
203 */
204void rds_tcp_conn_path_shutdown(struct rds_conn_path *cp)
205{
206	struct rds_tcp_connection *tc = cp->cp_transport_data;
207	struct socket *sock = tc->t_sock;
208
209	rdsdebug("shutting down conn %p tc %p sock %p\n",
210		 cp->cp_conn, tc, sock);
211
212	if (sock) {
213		if (rds_destroy_pending(cp->cp_conn))
214			sock_no_linger(sock->sk);
215		sock->ops->shutdown(sock, RCV_SHUTDOWN | SEND_SHUTDOWN);
216		lock_sock(sock->sk);
217		rds_tcp_restore_callbacks(sock, tc); /* tc->tc_sock = NULL */
218
219		release_sock(sock->sk);
220		sock_release(sock);
221	}
222
223	if (tc->t_tinc) {
224		rds_inc_put(&tc->t_tinc->ti_inc);
225		tc->t_tinc = NULL;
226	}
227	tc->t_tinc_hdr_rem = sizeof(struct rds_header);
228	tc->t_tinc_data_rem = 0;
229}
230