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 char * const rds_trans_modules[] = {
 42	[RDS_TRANS_IB] = "rds_rdma",
 43	[RDS_TRANS_GAP] = NULL,
 44	[RDS_TRANS_TCP] = "rds_tcp",
 45};
 46
 47static struct rds_transport *transports[RDS_TRANS_COUNT];
 48static DECLARE_RWSEM(rds_trans_sem);
 49
 50void rds_trans_register(struct rds_transport *trans)
 51{
 52	BUG_ON(strlen(trans->t_name) + 1 > TRANSNAMSIZ);
 53
 54	down_write(&rds_trans_sem);
 55
 56	if (transports[trans->t_type])
 57		printk(KERN_ERR "RDS Transport type %d already registered\n",
 58			trans->t_type);
 59	else {
 60		transports[trans->t_type] = trans;
 61		printk(KERN_INFO "Registered RDS/%s transport\n", trans->t_name);
 62	}
 63
 64	up_write(&rds_trans_sem);
 65}
 66EXPORT_SYMBOL_GPL(rds_trans_register);
 67
 68void rds_trans_unregister(struct rds_transport *trans)
 69{
 70	down_write(&rds_trans_sem);
 71
 72	transports[trans->t_type] = NULL;
 73	printk(KERN_INFO "Unregistered RDS/%s transport\n", trans->t_name);
 74
 75	up_write(&rds_trans_sem);
 76}
 77EXPORT_SYMBOL_GPL(rds_trans_unregister);
 78
 79void rds_trans_put(struct rds_transport *trans)
 80{
 81	if (trans)
 82		module_put(trans->t_owner);
 83}
 84
 85struct rds_transport *rds_trans_get_preferred(struct net *net,
 86					      const struct in6_addr *addr,
 87					      __u32 scope_id)
 88{
 89	struct rds_transport *ret = NULL;
 90	struct rds_transport *trans;
 91	unsigned int i;
 92
 93	if (ipv6_addr_v4mapped(addr)) {
 94		if (*(u_int8_t *)&addr->s6_addr32[3] == IN_LOOPBACKNET)
 95			return &rds_loop_transport;
 96	} else if (ipv6_addr_loopback(addr)) {
 97		return &rds_loop_transport;
 98	}
 99
100	down_read(&rds_trans_sem);
101	for (i = 0; i < RDS_TRANS_COUNT; i++) {
102		trans = transports[i];
103
104		if (trans && (trans->laddr_check(net, addr, scope_id) == 0) &&
105		    (!trans->t_owner || try_module_get(trans->t_owner))) {
106			ret = trans;
107			break;
108		}
109	}
110	up_read(&rds_trans_sem);
111
112	return ret;
113}
114
115struct rds_transport *rds_trans_get(int t_type)
116{
117	struct rds_transport *ret = NULL;
118	struct rds_transport *trans;
119
120	down_read(&rds_trans_sem);
121	trans = transports[t_type];
122	if (!trans) {
123		up_read(&rds_trans_sem);
124		if (rds_trans_modules[t_type])
125			request_module(rds_trans_modules[t_type]);
126		down_read(&rds_trans_sem);
127		trans = transports[t_type];
128	}
129	if (trans && trans->t_type == t_type &&
130	    (!trans->t_owner || try_module_get(trans->t_owner)))
131		ret = trans;
132
133	up_read(&rds_trans_sem);
134
135	return ret;
136}
137
138/*
139 * This returns the number of stats entries in the snapshot and only
140 * copies them using the iter if there is enough space for them.  The
141 * caller passes in the global stats so that we can size and copy while
142 * holding the lock.
143 */
144unsigned int rds_trans_stats_info_copy(struct rds_info_iterator *iter,
145				       unsigned int avail)
146
147{
148	struct rds_transport *trans;
149	unsigned int total = 0;
150	unsigned int part;
151	int i;
152
153	rds_info_iter_unmap(iter);
154	down_read(&rds_trans_sem);
155
156	for (i = 0; i < RDS_TRANS_COUNT; i++) {
157		trans = transports[i];
158		if (!trans || !trans->stats_info_copy)
159			continue;
160
161		part = trans->stats_info_copy(iter, avail);
162		avail -= min(avail, part);
163		total += part;
164	}
165
166	up_read(&rds_trans_sem);
167
168	return total;
169}