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 char * const rds_trans_modules[] = {
42 	[RDS_TRANS_IB] = "rds_rdma",
43 	[RDS_TRANS_GAP] = NULL,
44 	[RDS_TRANS_TCP] = "rds_tcp",
45 };
46 
47 static struct rds_transport *transports[RDS_TRANS_COUNT];
48 static DECLARE_RWSEM(rds_trans_sem);
49 
rds_trans_register(struct rds_transport * trans)50 void 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 }
66 EXPORT_SYMBOL_GPL(rds_trans_register);
67 
rds_trans_unregister(struct rds_transport * trans)68 void 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 }
77 EXPORT_SYMBOL_GPL(rds_trans_unregister);
78 
rds_trans_put(struct rds_transport * trans)79 void rds_trans_put(struct rds_transport *trans)
80 {
81 	if (trans)
82 		module_put(trans->t_owner);
83 }
84 
rds_trans_get_preferred(struct net * net,const struct in6_addr * addr,__u32 scope_id)85 struct 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 
rds_trans_get(int t_type)115 struct 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  */
rds_trans_stats_info_copy(struct rds_info_iterator * iter,unsigned int avail)144 unsigned 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 }
170