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
41struct ibnl_client {
42	struct list_head		list;
43	int				index;
44	int				nops;
45	const struct ibnl_client_cbs   *cb_table;
46};
47
48static DEFINE_MUTEX(ibnl_mutex);
49static struct sock *nls;
50static LIST_HEAD(client_list);
51
52int 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}
83EXPORT_SYMBOL(ibnl_add_client);
84
85int 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}
103EXPORT_SYMBOL(ibnl_remove_client);
104
105void *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_NEW(skb, 0, seq, RDMA_NL_GET_TYPE(client, op),
112			len, NLM_F_MULTI);
113	(*nlh)->nlmsg_len = skb_tail_pointer(skb) - prev_tail;
114	return NLMSG_DATA(*nlh);
115
116nlmsg_failure:
117	nlmsg_trim(skb, prev_tail);
118	return NULL;
119}
120EXPORT_SYMBOL(ibnl_put_msg);
121
122int ibnl_put_attr(struct sk_buff *skb, struct nlmsghdr *nlh,
123		  int len, void *data, int type)
124{
125	unsigned char *prev_tail;
126
127	prev_tail = skb_tail_pointer(skb);
128	NLA_PUT(skb, type, len, data);
129	nlh->nlmsg_len += skb_tail_pointer(skb) - prev_tail;
130	return 0;
131
132nla_put_failure:
133	nlmsg_trim(skb, prev_tail - nlh->nlmsg_len);
134	return -EMSGSIZE;
135}
136EXPORT_SYMBOL(ibnl_put_attr);
137
138static int ibnl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
139{
140	struct ibnl_client *client;
141	int type = nlh->nlmsg_type;
142	int index = RDMA_NL_GET_CLIENT(type);
143	int op = RDMA_NL_GET_OP(type);
144
145	list_for_each_entry(client, &client_list, list) {
146		if (client->index == index) {
147			if (op < 0 || op >= client->nops ||
148			    !client->cb_table[RDMA_NL_GET_OP(op)].dump)
149				return -EINVAL;
150			return netlink_dump_start(nls, skb, nlh,
151						  client->cb_table[op].dump,
152						  NULL, 0);
153		}
154	}
155
156	pr_info("Index %d wasn't found in client list\n", index);
157	return -EINVAL;
158}
159
160static void ibnl_rcv(struct sk_buff *skb)
161{
162	mutex_lock(&ibnl_mutex);
163	netlink_rcv_skb(skb, &ibnl_rcv_msg);
164	mutex_unlock(&ibnl_mutex);
165}
166
167int __init ibnl_init(void)
168{
169	nls = netlink_kernel_create(&init_net, NETLINK_RDMA, 0, ibnl_rcv,
170				    NULL, THIS_MODULE);
171	if (!nls) {
172		pr_warn("Failed to create netlink socket\n");
173		return -ENOMEM;
174	}
175
176	return 0;
177}
178
179void ibnl_cleanup(void)
180{
181	struct ibnl_client *cur, *next;
182
183	mutex_lock(&ibnl_mutex);
184	list_for_each_entry_safe(cur, next, &client_list, list) {
185		list_del(&(cur->list));
186		kfree(cur);
187	}
188	mutex_unlock(&ibnl_mutex);
189
190	netlink_kernel_release(nls);
191}
192