net/rds/transport.c

   1 /*
   2  * Copyright (c) 2006, 2017 Oracle and/or its affiliates. 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 <linux/module.h>
  35 #include <linux/in.h>
  36 #include <linux/ipv6.h>
  37
  38 #include "rds.h"
  39 #include "loop.h"
  40
  41 static struct rds_transport *transports[RDS_TRANS_COUNT];
  42 static DECLARE_RWSEM(rds_trans_sem);
  43
  44 void rds_trans_register(struct rds_transport *trans)
  45 {
  46         BUG_ON(strlen(trans->t_name) + 1 > TRANSNAMSIZ);
  47
  48         down_write(&rds_trans_sem);
  49
  50         if (transports[trans->t_type])
  51                 printk(KERN_ERR "RDS Transport type %d already registered\n",
  52                         trans->t_type);
  53         else {
  54                 transports[trans->t_type] = trans;
  55                 printk(KERN_INFO "Registered RDS/%s transport\n", trans->t_name);
  56         }
  57
  58         up_write(&rds_trans_sem);
  59 }
  60 EXPORT_SYMBOL_GPL(rds_trans_register);
  61
  62 void rds_trans_unregister(struct rds_transport *trans)
  63 {
  64         down_write(&rds_trans_sem);
  65
  66         transports[trans->t_type] = NULL;
  67         printk(KERN_INFO "Unregistered RDS/%s transport\n", trans->t_name);
  68
  69         up_write(&rds_trans_sem);
  70 }
  71 EXPORT_SYMBOL_GPL(rds_trans_unregister);
  72
  73 void rds_trans_put(struct rds_transport *trans)
  74 {
  75         if (trans)
  76                 module_put(trans->t_owner);
  77 }
  78
  79 struct rds_transport *rds_trans_get_preferred(struct net *net,
  80                                               const struct in6_addr *addr,
  81                                               __u32 scope_id)
  82 {
  83         struct rds_transport *ret = NULL;
  84         struct rds_transport *trans;
  85         unsigned int i;
  86
  87         if (ipv6_addr_v4mapped(addr)) {
  88                 if (*(u_int8_t *)&addr->s6_addr32[3] == IN_LOOPBACKNET)
  89                         return &rds_loop_transport;
  90         } else if (ipv6_addr_loopback(addr)) {
  91                 return &rds_loop_transport;
  92         }
  93
  94         down_read(&rds_trans_sem);
  95         for (i = 0; i < RDS_TRANS_COUNT; i++) {
  96                 trans = transports[i];
  97
  98                 if (trans && (trans->laddr_check(net, addr, scope_id) == 0) &&
  99                     (!trans->t_owner || try_module_get(trans->t_owner))) {
 100                         ret = trans;
 101                         break;
 102                 }
 103         }
 104         up_read(&rds_trans_sem);
 105
 106         return ret;
 107 }
 108
 109 struct rds_transport *rds_trans_get(int t_type)
 110 {
 111         struct rds_transport *ret = NULL;
 112         struct rds_transport *trans;
 113         unsigned int i;
 114
 115         down_read(&rds_trans_sem);
 116         for (i = 0; i < RDS_TRANS_COUNT; i++) {
 117                 trans = transports[i];
 118
 119                 if (trans && trans->t_type == t_type &&
 120                     (!trans->t_owner || try_module_get(trans->t_owner))) {
 121                         ret = trans;
 122                         break;
 123                 }
 124         }
 125         up_read(&rds_trans_sem);
 126
 127         return ret;
 128 }
 129
 130 /*
 131  * This returns the number of stats entries in the snapshot and only
 132  * copies them using the iter if there is enough space for them.  The
 133  * caller passes in the global stats so that we can size and copy while
 134  * holding the lock.
 135  */
 136 unsigned int rds_trans_stats_info_copy(struct rds_info_iterator *iter,
 137                                        unsigned int avail)
 138
 139 {
 140         struct rds_transport *trans;
 141         unsigned int total = 0;
 142         unsigned int part;
 143         int i;
 144
 145         rds_info_iter_unmap(iter);
 146         down_read(&rds_trans_sem);
 147
 148         for (i = 0; i < RDS_TRANS_COUNT; i++) {
 149                 trans = transports[i];
 150                 if (!trans || !trans->stats_info_copy)
 151                         continue;
 152
 153                 part = trans->stats_info_copy(iter, avail);
 154                 avail -= min(avail, part);
 155                 total += part;
 156         }
 157
 158         up_read(&rds_trans_sem);
 159
 160         return total;
 161 }