net/rds/bind.c


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

/*
 * 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 <net/sock.h>
#include <linux/in.h>
#include <linux/if_arp.h>
#include <linux/jhash.h>
#include <linux/ratelimit.h>
#include "rds.h"

#define BIND_HASH_SIZE 1024
static struct hlist_head bind_hash_table[BIND_HASH_SIZE];
static DEFINE_SPINLOCK(rds_bind_lock);

static struct hlist_head *hash_to_bucket(__be32 addr, __be16 port)
{
	return bind_hash_table + (jhash_2words((u32)addr, (u32)port, 0) &
				  (BIND_HASH_SIZE - 1));
}

static struct rds_sock *rds_bind_lookup(__be32 addr, __be16 port,
					struct rds_sock *insert)
{
	struct rds_sock *rs;
	struct hlist_head *head = hash_to_bucket(addr, port);
	u64 cmp;
	u64 needle = ((u64)be32_to_cpu(addr) << 32) | be16_to_cpu(port);

	rcu_read_lock();
	hlist_for_each_entry_rcu(rs, head, rs_bound_node) {
		cmp = ((u64)be32_to_cpu(rs->rs_bound_addr) << 32) |
		      be16_to_cpu(rs->rs_bound_port);

		if (cmp == needle) {
			rcu_read_unlock();
			return rs;
		}
	}
	rcu_read_unlock();

	if (insert) {
		/*
		 * make sure our addr and port are set before
		 * we are added to the list, other people
		 * in rcu will find us as soon as the
		 * hlist_add_head_rcu is done
		 */
		insert->rs_bound_addr = addr;
		insert->rs_bound_port = port;
		rds_sock_addref(insert);

		hlist_add_head_rcu(&insert->rs_bound_node, head);
	}
	return NULL;
}

/*
 * Return the rds_sock bound at the given local address.
 *
 * The rx path can race with rds_release.  We notice if rds_release() has
 * marked this socket and don't return a rs ref to the rx path.
 */
struct rds_sock *rds_find_bound(__be32 addr, __be16 port)
{
	struct rds_sock *rs;

	rs = rds_bind_lookup(addr, port, NULL);

	if (rs && !sock_flag(rds_rs_to_sk(rs), SOCK_DEAD))
		rds_sock_addref(rs);
	else
		rs = NULL;

	rdsdebug("returning rs %p for %pI4:%u\n", rs, &addr,
		ntohs(port));
	return rs;
}

/* returns -ve errno or +ve port */
static int rds_add_bound(struct rds_sock *rs, __be32 addr, __be16 *port)
{
	unsigned long flags;
	int ret = -EADDRINUSE;
	u16 rover, last;

	if (*port != 0) {
		rover = be16_to_cpu(*port);
		last = rover;
	} else {
		rover = max_t(u16, prandom_u32(), 2);
		last = rover - 1;
	}

	spin_lock_irqsave(&rds_bind_lock, flags);

	do {
		if (rover == 0)
			rover++;
		if (!rds_bind_lookup(addr, cpu_to_be16(rover), rs)) {
			*port = rs->rs_bound_port;
			ret = 0;
			rdsdebug("rs %p binding to %pI4:%d\n",
			  rs, &addr, (int)ntohs(*port));
			break;
		}
	} while (rover++ != last);

	spin_unlock_irqrestore(&rds_bind_lock, flags);

	return ret;
}

void rds_remove_bound(struct rds_sock *rs)
{
	unsigned long flags;

	spin_lock_irqsave(&rds_bind_lock, flags);

	if (rs->rs_bound_addr) {
		rdsdebug("rs %p unbinding from %pI4:%d\n",
		  rs, &rs->rs_bound_addr,
		  ntohs(rs->rs_bound_port));

		hlist_del_init_rcu(&rs->rs_bound_node);
		rds_sock_put(rs);
		rs->rs_bound_addr = 0;
	}

	spin_unlock_irqrestore(&rds_bind_lock, flags);
}

int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
	struct sock *sk = sock->sk;
	struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
	struct rds_sock *rs = rds_sk_to_rs(sk);
	struct rds_transport *trans;
	int ret = 0;

	lock_sock(sk);

	if (addr_len != sizeof(struct sockaddr_in) ||
	    sin->sin_family != AF_INET ||
	    rs->rs_bound_addr ||
	    sin->sin_addr.s_addr == htonl(INADDR_ANY)) {
		ret = -EINVAL;
		goto out;
	}

	ret = rds_add_bound(rs, sin->sin_addr.s_addr, &sin->sin_port);
	if (ret)
		goto out;

	trans = rds_trans_get_preferred(sin->sin_addr.s_addr);
	if (!trans) {
		ret = -EADDRNOTAVAIL;
		rds_remove_bound(rs);
		printk_ratelimited(KERN_INFO "RDS: rds_bind() could not find a transport, "
				"load rds_tcp or rds_rdma?\n");
		goto out;
	}

	rs->rs_transport = trans;
	ret = 0;

out:
	release_sock(sk);

	/* we might have called rds_remove_bound on error */
	if (ret)
		synchronize_rcu();
	return ret;
}