1 /*
2  * Copyright (c) 2010 Voltaire Inc.  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 #define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__
34 
35 #include <linux/export.h>
36 #include <net/netlink.h>
37 #include <net/net_namespace.h>
38 #include <net/sock.h>
39 #include <rdma/rdma_netlink.h>
40 
41 struct ibnl_client {
42 	struct list_head		list;
43 	int				index;
44 	int				nops;
45 	const struct ibnl_client_cbs   *cb_table;
46 };
47 
48 static DEFINE_MUTEX(ibnl_mutex);
49 static struct sock *nls;
50 static LIST_HEAD(client_list);
51 
52 int ibnl_add_client(int index, int nops,
53 		    const struct ibnl_client_cbs cb_table[])
54 {
55 	struct ibnl_client *cur;
56 	struct ibnl_client *nl_client;
57 
58 	nl_client = kmalloc(sizeof *nl_client, GFP_KERNEL);
59 	if (!nl_client)
60 		return -ENOMEM;
61 
62 	nl_client->index	= index;
63 	nl_client->nops		= nops;
64 	nl_client->cb_table	= cb_table;
65 
66 	mutex_lock(&ibnl_mutex);
67 
68 	list_for_each_entry(cur, &client_list, list) {
69 		if (cur->index == index) {
70 			pr_warn("Client for %d already exists\n", index);
71 			mutex_unlock(&ibnl_mutex);
72 			kfree(nl_client);
73 			return -EINVAL;
74 		}
75 	}
76 
77 	list_add_tail(&nl_client->list, &client_list);
78 
79 	mutex_unlock(&ibnl_mutex);
80 
81 	return 0;
82 }
83 EXPORT_SYMBOL(ibnl_add_client);
84 
85 int ibnl_remove_client(int index)
86 {
87 	struct ibnl_client *cur, *next;
88 
89 	mutex_lock(&ibnl_mutex);
90 	list_for_each_entry_safe(cur, next, &client_list, list) {
91 		if (cur->index == index) {
92 			list_del(&(cur->list));
93 			mutex_unlock(&ibnl_mutex);
94 			kfree(cur);
95 			return 0;
96 		}
97 	}
98 	pr_warn("Can't remove callback for client idx %d. Not found\n", index);
99 	mutex_unlock(&ibnl_mutex);
100 
101 	return -EINVAL;
102 }
103 EXPORT_SYMBOL(ibnl_remove_client);
104 
105 void *ibnl_put_msg(struct sk_buff *skb, struct nlmsghdr **nlh, int seq,
106 		   int len, int client, int op)
107 {
108 	unsigned char *prev_tail;
109 
110 	prev_tail = skb_tail_pointer(skb);
111 	*nlh = nlmsg_put(skb, 0, seq, RDMA_NL_GET_TYPE(client, op),
112 			 len, NLM_F_MULTI);
113 	if (!*nlh)
114 		goto out_nlmsg_trim;
115 	(*nlh)->nlmsg_len = skb_tail_pointer(skb) - prev_tail;
116 	return nlmsg_data(*nlh);
117 
118 out_nlmsg_trim:
119 	nlmsg_trim(skb, prev_tail);
120 	return NULL;
121 }
122 EXPORT_SYMBOL(ibnl_put_msg);
123 
124 int ibnl_put_attr(struct sk_buff *skb, struct nlmsghdr *nlh,
125 		  int len, void *data, int type)
126 {
127 	unsigned char *prev_tail;
128 
129 	prev_tail = skb_tail_pointer(skb);
130 	if (nla_put(skb, type, len, data))
131 		goto nla_put_failure;
132 	nlh->nlmsg_len += skb_tail_pointer(skb) - prev_tail;
133 	return 0;
134 
135 nla_put_failure:
136 	nlmsg_trim(skb, prev_tail - nlh->nlmsg_len);
137 	return -EMSGSIZE;
138 }
139 EXPORT_SYMBOL(ibnl_put_attr);
140 
141 static int ibnl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
142 {
143 	struct ibnl_client *client;
144 	int type = nlh->nlmsg_type;
145 	int index = RDMA_NL_GET_CLIENT(type);
146 	int op = RDMA_NL_GET_OP(type);
147 
148 	list_for_each_entry(client, &client_list, list) {
149 		if (client->index == index) {
150 			if (op < 0 || op >= client->nops ||
151 			    !client->cb_table[op].dump)
152 				return -EINVAL;
153 
154 			{
155 				struct netlink_dump_control c = {
156 					.dump = client->cb_table[op].dump,
157 					.module = client->cb_table[op].module,
158 				};
159 				return netlink_dump_start(nls, skb, nlh, &c);
160 			}
161 		}
162 	}
163 
164 	pr_info("Index %d wasn't found in client list\n", index);
165 	return -EINVAL;
166 }
167 
168 static void ibnl_rcv(struct sk_buff *skb)
169 {
170 	mutex_lock(&ibnl_mutex);
171 	netlink_rcv_skb(skb, &ibnl_rcv_msg);
172 	mutex_unlock(&ibnl_mutex);
173 }
174 
175 int __init ibnl_init(void)
176 {
177 	struct netlink_kernel_cfg cfg = {
178 		.input	= ibnl_rcv,
179 	};
180 
181 	nls = netlink_kernel_create(&init_net, NETLINK_RDMA, &cfg);
182 	if (!nls) {
183 		pr_warn("Failed to create netlink socket\n");
184 		return -ENOMEM;
185 	}
186 
187 	return 0;
188 }
189 
190 void ibnl_cleanup(void)
191 {
192 	struct ibnl_client *cur, *next;
193 
194 	mutex_lock(&ibnl_mutex);
195 	list_for_each_entry_safe(cur, next, &client_list, list) {
196 		list_del(&(cur->list));
197 		kfree(cur);
198 	}
199 	mutex_unlock(&ibnl_mutex);
200 
201 	netlink_kernel_release(nls);
202 }
203