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 <linux/jhash.h>
  38 #include <linux/ratelimit.h>
  39 #include "rds.h"
  40
  41 #define BIND_HASH_SIZE 1024
  42 static struct hlist_head bind_hash_table[BIND_HASH_SIZE];
  43 static DEFINE_SPINLOCK(rds_bind_lock);
  44
  45 static struct hlist_head *hash_to_bucket(__be32 addr, __be16 port)
  46 {
  47         return bind_hash_table + (jhash_2words((u32)addr, (u32)port, 0) &
  48                                   (BIND_HASH_SIZE - 1));
  49 }
  50
  51 static struct rds_sock *rds_bind_lookup(__be32 addr, __be16 port,
  52                                         struct rds_sock *insert)
  53 {
  54         struct rds_sock *rs;
  55         struct hlist_node *node;
  56         struct hlist_head *head = hash_to_bucket(addr, port);
  57         u64 cmp;
  58         u64 needle = ((u64)be32_to_cpu(addr) << 32) | be16_to_cpu(port);
  59
  60         rcu_read_lock();
  61         hlist_for_each_entry_rcu(rs, node, head, rs_bound_node) {
  62                 cmp = ((u64)be32_to_cpu(rs->rs_bound_addr) << 32) |
  63                       be16_to_cpu(rs->rs_bound_port);
  64
  65                 if (cmp == needle) {
  66                         rcu_read_unlock();
  67                         return rs;
  68                 }
  69         }
  70         rcu_read_unlock();
  71
  72         if (insert) {
  73                 /*
  74                  * make sure our addr and port are set before
  75                  * we are added to the list, other people
  76                  * in rcu will find us as soon as the
  77                  * hlist_add_head_rcu is done
  78                  */
  79                 insert->rs_bound_addr = addr;
  80                 insert->rs_bound_port = port;
  81                 rds_sock_addref(insert);
  82
  83                 hlist_add_head_rcu(&insert->rs_bound_node, head);
  84         }
  85         return NULL;
  86 }
  87
  88 /*
  89  * Return the rds_sock bound at the given local address.
  90  *
  91  * The rx path can race with rds_release.  We notice if rds_release() has
  92  * marked this socket and don't return a rs ref to the rx path.
  93  */
  94 struct rds_sock *rds_find_bound(__be32 addr, __be16 port)
  95 {
  96         struct rds_sock *rs;
  97
  98         rs = rds_bind_lookup(addr, port, NULL);
  99
 100         if (rs && !sock_flag(rds_rs_to_sk(rs), SOCK_DEAD))
 101                 rds_sock_addref(rs);
 102         else
 103                 rs = NULL;
 104
 105         rdsdebug("returning rs %p for %pI4:%u\n", rs, &addr,
 106                 ntohs(port));
 107         return rs;
 108 }
 109
 110 /* returns -ve errno or +ve port */
 111 static int rds_add_bound(struct rds_sock *rs, __be32 addr, __be16 *port)
 112 {
 113         unsigned long flags;
 114         int ret = -EADDRINUSE;
 115         u16 rover, last;
 116
 117         if (*port != 0) {
 118                 rover = be16_to_cpu(*port);
 119                 last = rover;
 120         } else {
 121                 rover = max_t(u16, net_random(), 2);
 122                 last = rover - 1;
 123         }
 124
 125         spin_lock_irqsave(&rds_bind_lock, flags);
 126
 127         do {
 128                 if (rover == 0)
 129                         rover++;
 130                 if (!rds_bind_lookup(addr, cpu_to_be16(rover), rs)) {
 131                         *port = rs->rs_bound_port;
 132                         ret = 0;
 133                         rdsdebug("rs %p binding to %pI4:%d\n",
 134                           rs, &addr, (int)ntohs(*port));
 135                         break;
 136                 }
 137         } while (rover++ != last);
 138
 139         spin_unlock_irqrestore(&rds_bind_lock, flags);
 140
 141         return ret;
 142 }
 143
 144 void rds_remove_bound(struct rds_sock *rs)
 145 {
 146         unsigned long flags;
 147
 148         spin_lock_irqsave(&rds_bind_lock, flags);
 149
 150         if (rs->rs_bound_addr) {
 151                 rdsdebug("rs %p unbinding from %pI4:%d\n",
 152                   rs, &rs->rs_bound_addr,
 153                   ntohs(rs->rs_bound_port));
 154
 155                 hlist_del_init_rcu(&rs->rs_bound_node);
 156                 rds_sock_put(rs);
 157                 rs->rs_bound_addr = 0;
 158         }
 159
 160         spin_unlock_irqrestore(&rds_bind_lock, flags);
 161 }
 162
 163 int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 164 {
 165         struct sock *sk = sock->sk;
 166         struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
 167         struct rds_sock *rs = rds_sk_to_rs(sk);
 168         struct rds_transport *trans;
 169         int ret = 0;
 170
 171         lock_sock(sk);
 172
 173         if (addr_len != sizeof(struct sockaddr_in) ||
 174             sin->sin_family != AF_INET ||
 175             rs->rs_bound_addr ||
 176             sin->sin_addr.s_addr == htonl(INADDR_ANY)) {
 177                 ret = -EINVAL;
 178                 goto out;
 179         }
 180
 181         ret = rds_add_bound(rs, sin->sin_addr.s_addr, &sin->sin_port);
 182         if (ret)
 183                 goto out;
 184
 185         trans = rds_trans_get_preferred(sin->sin_addr.s_addr);
 186         if (!trans) {
 187                 ret = -EADDRNOTAVAIL;
 188                 rds_remove_bound(rs);
 189                 printk_ratelimited(KERN_INFO "RDS: rds_bind() could not find a transport, "
 190                                 "load rds_tcp or rds_rdma?\n");
 191                 goto out;
 192         }
 193
 194         rs->rs_transport = trans;
 195         ret = 0;
 196
 197 out:
 198         release_sock(sk);
 199
 200         /* we might have called rds_remove_bound on error */
 201         if (ret)
 202                 synchronize_rcu();
 203         return ret;
 204 }