blob: 6ecfa758942c50a4b33ebd399cd831ac1420277d [file] [log] [blame]
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -07001/*
Valentin Ilief3c48ec2012-07-14 13:08:29 +00002 * connector.c
Frederic Weisbecker1a5645b2009-02-02 23:22:04 -08003 *
Evgeniy Polyakovacb9c1b2009-07-21 12:43:51 -07004 * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -07005 * All rights reserved.
Frederic Weisbecker1a5645b2009-02-02 23:22:04 -08006 *
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -07007 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/list.h>
25#include <linux/skbuff.h>
Hong zhi guo9631d792013-03-27 06:54:56 +000026#include <net/netlink.h>
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -070027#include <linux/moduleparam.h>
28#include <linux/connector.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090029#include <linux/slab.h>
Arjan van de Ven8ed965d2006-03-23 03:00:21 -080030#include <linux/mutex.h>
Li Zefana0a61a62008-06-27 20:03:24 -070031#include <linux/proc_fs.h>
32#include <linux/spinlock.h>
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -070033
34#include <net/sock.h>
35
36MODULE_LICENSE("GPL");
Evgeniy Polyakovacb9c1b2009-07-21 12:43:51 -070037MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -070038MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
Stephen Hemminger3700c3c2010-12-10 12:27:49 -080039MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_CONNECTOR);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -070040
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -070041static struct cn_dev cdev;
42
Li Zefan78374672008-02-26 18:25:53 -080043static int cn_already_initialized;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -070044
45/*
46 * msg->seq and msg->ack are used to determine message genealogy.
47 * When someone sends message it puts there locally unique sequence
48 * and random acknowledge numbers. Sequence number may be copied into
49 * nlmsghdr->nlmsg_seq too.
50 *
51 * Sequence number is incremented with each message to be sent.
52 *
53 * If we expect reply to our message then the sequence number in
54 * received message MUST be the same as in original message, and
55 * acknowledge number MUST be the same + 1.
56 *
57 * If we receive a message and its sequence number is not equal to the
58 * one we are expecting then it is a new message.
59 *
60 * If we receive a message and its sequence number is the same as one
61 * we are expecting but it's acknowledgement number is not equal to
62 * the acknowledgement number in the original message + 1, then it is
63 * a new message.
64 *
65 */
Al Virodd0fc662005-10-07 07:46:04 +010066int cn_netlink_send(struct cn_msg *msg, u32 __group, gfp_t gfp_mask)
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -070067{
68 struct cn_callback_entry *__cbq;
69 unsigned int size;
70 struct sk_buff *skb;
71 struct nlmsghdr *nlh;
72 struct cn_msg *data;
73 struct cn_dev *dev = &cdev;
74 u32 group = 0;
75 int found = 0;
76
77 if (!__group) {
78 spin_lock_bh(&dev->cbdev->queue_lock);
79 list_for_each_entry(__cbq, &dev->cbdev->queue_list,
80 callback_entry) {
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -070081 if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -070082 found = 1;
83 group = __cbq->group;
Li Zefanfd00eec2008-01-04 01:54:38 -080084 break;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -070085 }
86 }
87 spin_unlock_bh(&dev->cbdev->queue_lock);
88
89 if (!found)
90 return -ENODEV;
91 } else {
92 group = __group;
93 }
94
Evgeniy Polyakovb191ba02006-03-20 22:21:40 -080095 if (!netlink_has_listeners(dev->nls, group))
96 return -ESRCH;
97
Hong zhi guo9631d792013-03-27 06:54:56 +000098 size = sizeof(*msg) + msg->len;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -070099
Hong zhi guo9631d792013-03-27 06:54:56 +0000100 skb = nlmsg_new(size, gfp_mask);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700101 if (!skb)
102 return -ENOMEM;
103
Hong zhi guo9631d792013-03-27 06:54:56 +0000104 nlh = nlmsg_put(skb, 0, msg->seq, NLMSG_DONE, size, 0);
Javier Martinez Canillas85c93162012-06-26 05:41:24 +0000105 if (!nlh) {
106 kfree_skb(skb);
107 return -EMSGSIZE;
108 }
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700109
Javier Martinez Canillas85c93162012-06-26 05:41:24 +0000110 data = nlmsg_data(nlh);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700111
112 memcpy(data, msg, sizeof(*data) + msg->len);
113
114 NETLINK_CB(skb).dst_group = group;
115
Evgeniy Polyakovb191ba02006-03-20 22:21:40 -0800116 return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700117}
Andrew Mortondeb0e9b2006-06-23 02:05:46 -0700118EXPORT_SYMBOL_GPL(cn_netlink_send);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700119
120/*
121 * Callback helper - queues work and setup destructor for given data.
122 */
Philipp Reisnerf1489cf2009-10-02 02:40:07 +0000123static int cn_call_callback(struct sk_buff *skb)
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700124{
Patrick McHardy04f482f2011-03-28 08:39:36 +0000125 struct cn_callback_entry *i, *cbq = NULL;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700126 struct cn_dev *dev = &cdev;
Hong zhi guo9631d792013-03-27 06:54:56 +0000127 struct cn_msg *msg = nlmsg_data(nlmsg_hdr(skb));
Patrick McHardy04f482f2011-03-28 08:39:36 +0000128 struct netlink_skb_parms *nsp = &NETLINK_CB(skb);
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -0700129 int err = -ENODEV;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700130
131 spin_lock_bh(&dev->cbdev->queue_lock);
Patrick McHardy04f482f2011-03-28 08:39:36 +0000132 list_for_each_entry(i, &dev->cbdev->queue_list, callback_entry) {
133 if (cn_cb_equal(&i->id.id, &msg->id)) {
134 atomic_inc(&i->refcnt);
135 cbq = i;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700136 break;
137 }
138 }
139 spin_unlock_bh(&dev->cbdev->queue_lock);
140
Patrick McHardy04f482f2011-03-28 08:39:36 +0000141 if (cbq != NULL) {
K. Y. Srinivasan663dd6d2011-05-17 15:25:38 -0700142 err = 0;
Patrick McHardy04f482f2011-03-28 08:39:36 +0000143 cbq->callback(msg, nsp);
144 kfree_skb(skb);
145 cn_queue_release_callback(cbq);
Patrick McHardy0e087852011-04-12 05:39:51 +0000146 err = 0;
Patrick McHardy04f482f2011-03-28 08:39:36 +0000147 }
148
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -0700149 return err;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700150}
151
152/*
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700153 * Main netlink receiving function.
154 *
Li Zefan00f5e062008-01-04 01:55:01 -0800155 * It checks skb, netlink header and msg sizes, and calls callback helper.
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700156 */
157static void cn_rx_skb(struct sk_buff *__skb)
158{
159 struct nlmsghdr *nlh;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700160 int err;
161 struct sk_buff *skb;
162
163 skb = skb_get(__skb);
164
Hong zhi guo9631d792013-03-27 06:54:56 +0000165 if (skb->len >= NLMSG_HDRLEN) {
Arnaldo Carvalho de Melob529ccf2007-04-25 19:08:35 -0700166 nlh = nlmsg_hdr(skb);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700167
168 if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
169 skb->len < nlh->nlmsg_len ||
170 nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
171 kfree_skb(skb);
Michal Januszewski6cf92e92007-10-30 20:41:49 -0700172 return;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700173 }
174
Philipp Reisnerf1489cf2009-10-02 02:40:07 +0000175 err = cn_call_callback(skb);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700176 if (err < 0)
177 kfree_skb(skb);
178 }
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700179}
180
181/*
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700182 * Callback add routing - adds callback with given ID and name.
183 * If there is registered callback with the same ID it will not be added.
184 *
185 * May sleep.
186 */
Joe Perches008536e2011-02-19 15:45:29 -0800187int cn_add_callback(struct cb_id *id, const char *name,
Valentin Ilief3c48ec2012-07-14 13:08:29 +0000188 void (*callback)(struct cn_msg *,
189 struct netlink_skb_parms *))
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700190{
191 int err;
192 struct cn_dev *dev = &cdev;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700193
Evgeniy Polyakovd6cc7f12006-06-19 23:42:53 -0700194 if (!cn_already_initialized)
195 return -EAGAIN;
196
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -0700197 err = cn_queue_add_callback(dev->cbdev, name, id, callback);
198 if (err)
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700199 return err;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700200
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700201 return 0;
202}
Andrew Mortondeb0e9b2006-06-23 02:05:46 -0700203EXPORT_SYMBOL_GPL(cn_add_callback);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700204
205/*
206 * Callback remove routing - removes callback
207 * with given ID.
208 * If there is no registered callback with given
209 * ID nothing happens.
210 *
211 * May sleep while waiting for reference counter to become zero.
212 */
213void cn_del_callback(struct cb_id *id)
214{
215 struct cn_dev *dev = &cdev;
216
217 cn_queue_del_callback(dev->cbdev, id);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700218}
Andrew Mortondeb0e9b2006-06-23 02:05:46 -0700219EXPORT_SYMBOL_GPL(cn_del_callback);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700220
Li Zefana0a61a62008-06-27 20:03:24 -0700221static int cn_proc_show(struct seq_file *m, void *v)
222{
223 struct cn_queue_dev *dev = cdev.cbdev;
224 struct cn_callback_entry *cbq;
225
226 seq_printf(m, "Name ID\n");
227
228 spin_lock_bh(&dev->queue_lock);
229
230 list_for_each_entry(cbq, &dev->queue_list, callback_entry) {
231 seq_printf(m, "%-15s %u:%u\n",
232 cbq->id.name,
233 cbq->id.id.idx,
234 cbq->id.id.val);
235 }
236
237 spin_unlock_bh(&dev->queue_lock);
238
239 return 0;
240}
241
242static int cn_proc_open(struct inode *inode, struct file *file)
243{
244 return single_open(file, cn_proc_show, NULL);
245}
246
247static const struct file_operations cn_file_ops = {
248 .owner = THIS_MODULE,
249 .open = cn_proc_open,
250 .read = seq_read,
251 .llseek = seq_lseek,
252 .release = single_release
253};
254
Pablo Neira Ayusoa31f2d12012-06-29 06:15:21 +0000255static struct cn_dev cdev = {
256 .input = cn_rx_skb,
257};
258
Greg Kroah-Hartman0fe763c2012-12-21 15:14:44 -0800259static int cn_init(void)
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700260{
261 struct cn_dev *dev = &cdev;
Pablo Neira Ayusoa31f2d12012-06-29 06:15:21 +0000262 struct netlink_kernel_cfg cfg = {
263 .groups = CN_NETLINK_USERS + 0xf,
264 .input = dev->input,
265 };
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700266
Pablo Neira Ayuso9f00d972012-09-08 02:53:54 +0000267 dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR, &cfg);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700268 if (!dev->nls)
269 return -EIO;
270
271 dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
272 if (!dev->cbdev) {
Denis V. Lunevb7c6ba62008-01-28 14:41:19 -0800273 netlink_kernel_release(dev->nls);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700274 return -EINVAL;
275 }
Frederic Weisbecker1a5645b2009-02-02 23:22:04 -0800276
Evgeniy Polyakovd6cc7f12006-06-19 23:42:53 -0700277 cn_already_initialized = 1;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700278
Gao fengd4beaa62013-02-18 01:34:54 +0000279 proc_create("connector", S_IRUGO, init_net.proc_net, &cn_file_ops);
Li Zefana0a61a62008-06-27 20:03:24 -0700280
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700281 return 0;
282}
283
Greg Kroah-Hartman0fe763c2012-12-21 15:14:44 -0800284static void cn_fini(void)
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700285{
286 struct cn_dev *dev = &cdev;
287
288 cn_already_initialized = 0;
289
Gao fengece31ff2013-02-18 01:34:56 +0000290 remove_proc_entry("connector", init_net.proc_net);
Li Zefana0a61a62008-06-27 20:03:24 -0700291
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700292 cn_queue_free_dev(dev->cbdev);
Denis V. Lunevb7c6ba62008-01-28 14:41:19 -0800293 netlink_kernel_release(dev->nls);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700294}
295
Evgeniy Polyakovd6cc7f12006-06-19 23:42:53 -0700296subsys_initcall(cn_init);
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700297module_exit(cn_fini);