/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
 41static struct rds_transport *transports[RDS_TRANS_COUNT];
 42static DECLARE_RWSEM(rds_trans_sem);
 43
 44void 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}
 60EXPORT_SYMBOL_GPL(rds_trans_register);
 61
 62void 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}
 71EXPORT_SYMBOL_GPL(rds_trans_unregister);
 72
 73void rds_trans_put(struct rds_transport *trans)
 74{
 75	if (trans)
 76		module_put(trans->t_owner);
 77}
 78
 79struct 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
109struct 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 */
136unsigned 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}