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  */
  46 static DEFINE_SPINLOCK(rds_bind_lock);
  47 static struct rb_root rds_bind_tree = RB_ROOT;
  48
  49 static 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  */
  86 struct 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 */
 105 static 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
 145 void 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
 164 int 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
 199 out:
 200         release_sock(sk);
 201         return ret;
 202 }