Root/net/rds/bind.c

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 <net/sock.h>
35#include <linux/in.h>
36#include <linux/if_arp.h>
37#include "rds.h"
38
39/*
40 * XXX this probably still needs more work.. no INADDR_ANY, and rbtrees aren't
41 * particularly zippy.
42 *
43 * This is now called for every incoming frame so we arguably care much more
44 * about it than we used to.
45 */
46static DEFINE_SPINLOCK(rds_bind_lock);
47static struct rb_root rds_bind_tree = RB_ROOT;
48
49static struct rds_sock *rds_bind_tree_walk(__be32 addr, __be16 port,
50                       struct rds_sock *insert)
51{
52    struct rb_node **p = &rds_bind_tree.rb_node;
53    struct rb_node *parent = NULL;
54    struct rds_sock *rs;
55    u64 cmp;
56    u64 needle = ((u64)be32_to_cpu(addr) << 32) | be16_to_cpu(port);
57
58    while (*p) {
59        parent = *p;
60        rs = rb_entry(parent, struct rds_sock, rs_bound_node);
61
62        cmp = ((u64)be32_to_cpu(rs->rs_bound_addr) << 32) |
63              be16_to_cpu(rs->rs_bound_port);
64
65        if (needle < cmp)
66            p = &(*p)->rb_left;
67        else if (needle > cmp)
68            p = &(*p)->rb_right;
69        else
70            return rs;
71    }
72
73    if (insert) {
74        rb_link_node(&insert->rs_bound_node, parent, p);
75        rb_insert_color(&insert->rs_bound_node, &rds_bind_tree);
76    }
77    return NULL;
78}
79
80/*
81 * Return the rds_sock bound at the given local address.
82 *
83 * The rx path can race with rds_release. We notice if rds_release() has
84 * marked this socket and don't return a rs ref to the rx path.
85 */
86struct rds_sock *rds_find_bound(__be32 addr, __be16 port)
87{
88    struct rds_sock *rs;
89    unsigned long flags;
90
91    spin_lock_irqsave(&rds_bind_lock, flags);
92    rs = rds_bind_tree_walk(addr, port, NULL);
93    if (rs && !sock_flag(rds_rs_to_sk(rs), SOCK_DEAD))
94        rds_sock_addref(rs);
95    else
96        rs = NULL;
97    spin_unlock_irqrestore(&rds_bind_lock, flags);
98
99    rdsdebug("returning rs %p for %pI4:%u\n", rs, &addr,
100        ntohs(port));
101    return rs;
102}
103
104/* returns -ve errno or +ve port */
105static int rds_add_bound(struct rds_sock *rs, __be32 addr, __be16 *port)
106{
107    unsigned long flags;
108    int ret = -EADDRINUSE;
109    u16 rover, last;
110
111    if (*port != 0) {
112        rover = be16_to_cpu(*port);
113        last = rover;
114    } else {
115        rover = max_t(u16, net_random(), 2);
116        last = rover - 1;
117    }
118
119    spin_lock_irqsave(&rds_bind_lock, flags);
120
121    do {
122        if (rover == 0)
123            rover++;
124        if (rds_bind_tree_walk(addr, cpu_to_be16(rover), rs) == NULL) {
125            *port = cpu_to_be16(rover);
126            ret = 0;
127            break;
128        }
129    } while (rover++ != last);
130
131    if (ret == 0) {
132        rs->rs_bound_addr = addr;
133        rs->rs_bound_port = *port;
134        rds_sock_addref(rs);
135
136        rdsdebug("rs %p binding to %pI4:%d\n",
137          rs, &addr, (int)ntohs(*port));
138    }
139
140    spin_unlock_irqrestore(&rds_bind_lock, flags);
141
142    return ret;
143}
144
145void rds_remove_bound(struct rds_sock *rs)
146{
147    unsigned long flags;
148
149    spin_lock_irqsave(&rds_bind_lock, flags);
150
151    if (rs->rs_bound_addr) {
152        rdsdebug("rs %p unbinding from %pI4:%d\n",
153          rs, &rs->rs_bound_addr,
154          ntohs(rs->rs_bound_port));
155
156        rb_erase(&rs->rs_bound_node, &rds_bind_tree);
157        rds_sock_put(rs);
158        rs->rs_bound_addr = 0;
159    }
160
161    spin_unlock_irqrestore(&rds_bind_lock, flags);
162}
163
164int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
165{
166    struct sock *sk = sock->sk;
167    struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
168    struct rds_sock *rs = rds_sk_to_rs(sk);
169    struct rds_transport *trans;
170    int ret = 0;
171
172    lock_sock(sk);
173
174    if (addr_len != sizeof(struct sockaddr_in) ||
175        sin->sin_family != AF_INET ||
176        rs->rs_bound_addr ||
177        sin->sin_addr.s_addr == htonl(INADDR_ANY)) {
178        ret = -EINVAL;
179        goto out;
180    }
181
182    ret = rds_add_bound(rs, sin->sin_addr.s_addr, &sin->sin_port);
183    if (ret)
184        goto out;
185
186    trans = rds_trans_get_preferred(sin->sin_addr.s_addr);
187    if (trans == NULL) {
188        ret = -EADDRNOTAVAIL;
189        rds_remove_bound(rs);
190        if (printk_ratelimit())
191            printk(KERN_INFO "RDS: rds_bind() could not find a transport, "
192                "load rds_tcp or rds_rdma?\n");
193        goto out;
194    }
195
196    rs->rs_transport = trans;
197    ret = 0;
198
199out:
200    release_sock(sk);
201    return ret;
202}
203

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