release/src-rt-6.x.4708/linux/linux-2.6.36/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 static DEFINE_SPINLOCK(rds_bind_lock);
  40 static struct rb_root rds_bind_tree = RB_ROOT;
  41
  42 static struct rds_sock *rds_bind_tree_walk(__be32 addr, __be16 port,
  43                                            struct rds_sock *insert)
  44 {
  45         struct rb_node **p = &rds_bind_tree.rb_node;
  46         struct rb_node *parent = NULL;
  47         struct rds_sock *rs;
  48         u64 cmp;
  49         u64 needle = ((u64)be32_to_cpu(addr) << 32) | be16_to_cpu(port);
  50
  51         while (*p) {
  52                 parent = *p;
  53                 rs = rb_entry(parent, struct rds_sock, rs_bound_node);
  54
  55                 cmp = ((u64)be32_to_cpu(rs->rs_bound_addr) << 32) |
  56                       be16_to_cpu(rs->rs_bound_port);
  57
  58                 if (needle < cmp)
  59                         p = &(*p)->rb_left;
  60                 else if (needle > cmp)
  61                         p = &(*p)->rb_right;
  62                 else
  63                         return rs;
  64         }
  65
  66         if (insert) {
  67                 rb_link_node(&insert->rs_bound_node, parent, p);
  68                 rb_insert_color(&insert->rs_bound_node, &rds_bind_tree);
  69         }
  70         return NULL;
  71 }
  72
  73 /*
  74  * Return the rds_sock bound at the given local address.
  75  *
  76  * The rx path can race with rds_release.  We notice if rds_release() has
  77  * marked this socket and don't return a rs ref to the rx path.
  78  */
  79 struct rds_sock *rds_find_bound(__be32 addr, __be16 port)
  80 {
  81         struct rds_sock *rs;
  82         unsigned long flags;
  83
  84         spin_lock_irqsave(&rds_bind_lock, flags);
  85         rs = rds_bind_tree_walk(addr, port, NULL);
  86         if (rs && !sock_flag(rds_rs_to_sk(rs), SOCK_DEAD))
  87                 rds_sock_addref(rs);
  88         else
  89                 rs = NULL;
  90         spin_unlock_irqrestore(&rds_bind_lock, flags);
  91
  92         rdsdebug("returning rs %p for %pI4:%u\n", rs, &addr,
  93                 ntohs(port));
  94         return rs;
  95 }
  96
  97 /* returns -ve errno or +ve port */
  98 static int rds_add_bound(struct rds_sock *rs, __be32 addr, __be16 *port)
  99 {
 100         unsigned long flags;
 101         int ret = -EADDRINUSE;
 102         u16 rover, last;
 103
 104         if (*port != 0) {
 105                 rover = be16_to_cpu(*port);
 106                 last = rover;
 107         } else {
 108                 rover = max_t(u16, net_random(), 2);
 109                 last = rover - 1;
 110         }
 111
 112         spin_lock_irqsave(&rds_bind_lock, flags);
 113
 114         do {
 115                 if (rover == 0)
 116                         rover++;
 117                 if (rds_bind_tree_walk(addr, cpu_to_be16(rover), rs) == NULL) {
 118                         *port = cpu_to_be16(rover);
 119                         ret = 0;
 120                         break;
 121                 }
 122         } while (rover++ != last);
 123
 124         if (ret == 0)  {
 125                 rs->rs_bound_addr = addr;
 126                 rs->rs_bound_port = *port;
 127                 rds_sock_addref(rs);
 128
 129                 rdsdebug("rs %p binding to %pI4:%d\n",
 130                   rs, &addr, (int)ntohs(*port));
 131         }
 132
 133         spin_unlock_irqrestore(&rds_bind_lock, flags);
 134
 135         return ret;
 136 }
 137
 138 void rds_remove_bound(struct rds_sock *rs)
 139 {
 140         unsigned long flags;
 141
 142         spin_lock_irqsave(&rds_bind_lock, flags);
 143
 144         if (rs->rs_bound_addr) {
 145                 rdsdebug("rs %p unbinding from %pI4:%d\n",
 146                   rs, &rs->rs_bound_addr,
 147                   ntohs(rs->rs_bound_port));
 148
 149                 rb_erase(&rs->rs_bound_node, &rds_bind_tree);
 150                 rds_sock_put(rs);
 151                 rs->rs_bound_addr = 0;
 152         }
 153
 154         spin_unlock_irqrestore(&rds_bind_lock, flags);
 155 }
 156
 157 int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 158 {
 159         struct sock *sk = sock->sk;
 160         struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
 161         struct rds_sock *rs = rds_sk_to_rs(sk);
 162         struct rds_transport *trans;
 163         int ret = 0;
 164
 165         lock_sock(sk);
 166
 167         if (addr_len != sizeof(struct sockaddr_in) ||
 168             sin->sin_family != AF_INET ||
 169             rs->rs_bound_addr ||
 170             sin->sin_addr.s_addr == htonl(INADDR_ANY)) {
 171                 ret = -EINVAL;
 172                 goto out;
 173         }
 174
 175         ret = rds_add_bound(rs, sin->sin_addr.s_addr, &sin->sin_port);
 176         if (ret)
 177                 goto out;
 178
 179         trans = rds_trans_get_preferred(sin->sin_addr.s_addr);
 180         if (trans == NULL) {
 181                 ret = -EADDRNOTAVAIL;
 182                 rds_remove_bound(rs);
 183                 if (printk_ratelimit())
 184                         printk(KERN_INFO "RDS: rds_bind() could not find a transport, "
 185                                 "load rds_tcp or rds_rdma?\n");
 186                 goto out;
 187         }
 188
 189         rs->rs_transport = trans;
 190         ret = 0;
 191
 192 out:
 193         release_sock(sk);
 194         return ret;
 195 }