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