Commit | Line | Data |
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7672d0b5 EP |
1 | /* |
2 | * connector.c | |
1a5645bc | 3 | * |
acb9c1b2 | 4 | * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net> |
7672d0b5 | 5 | * All rights reserved. |
1a5645bc | 6 | * |
7672d0b5 EP |
7 | * 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> | |
26 | #include <linux/netlink.h> | |
27 | #include <linux/moduleparam.h> | |
28 | #include <linux/connector.h> | |
5a0e3ad6 | 29 | #include <linux/slab.h> |
8ed965d6 | 30 | #include <linux/mutex.h> |
a0a61a60 LZ |
31 | #include <linux/proc_fs.h> |
32 | #include <linux/spinlock.h> | |
7672d0b5 EP |
33 | |
34 | #include <net/sock.h> | |
35 | ||
36 | MODULE_LICENSE("GPL"); | |
acb9c1b2 | 37 | MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>"); |
7672d0b5 EP |
38 | MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector."); |
39 | ||
7672d0b5 EP |
40 | static struct cn_dev cdev; |
41 | ||
78374676 | 42 | static int cn_already_initialized; |
7672d0b5 EP |
43 | |
44 | /* | |
45 | * msg->seq and msg->ack are used to determine message genealogy. | |
46 | * When someone sends message it puts there locally unique sequence | |
47 | * and random acknowledge numbers. Sequence number may be copied into | |
48 | * nlmsghdr->nlmsg_seq too. | |
49 | * | |
50 | * Sequence number is incremented with each message to be sent. | |
51 | * | |
52 | * If we expect reply to our message then the sequence number in | |
53 | * received message MUST be the same as in original message, and | |
54 | * acknowledge number MUST be the same + 1. | |
55 | * | |
56 | * If we receive a message and its sequence number is not equal to the | |
57 | * one we are expecting then it is a new message. | |
58 | * | |
59 | * If we receive a message and its sequence number is the same as one | |
60 | * we are expecting but it's acknowledgement number is not equal to | |
61 | * the acknowledgement number in the original message + 1, then it is | |
62 | * a new message. | |
63 | * | |
64 | */ | |
dd0fc66f | 65 | int cn_netlink_send(struct cn_msg *msg, u32 __group, gfp_t gfp_mask) |
7672d0b5 EP |
66 | { |
67 | struct cn_callback_entry *__cbq; | |
68 | unsigned int size; | |
69 | struct sk_buff *skb; | |
70 | struct nlmsghdr *nlh; | |
71 | struct cn_msg *data; | |
72 | struct cn_dev *dev = &cdev; | |
73 | u32 group = 0; | |
74 | int found = 0; | |
75 | ||
76 | if (!__group) { | |
77 | spin_lock_bh(&dev->cbdev->queue_lock); | |
78 | list_for_each_entry(__cbq, &dev->cbdev->queue_list, | |
79 | callback_entry) { | |
acd042bb | 80 | if (cn_cb_equal(&__cbq->id.id, &msg->id)) { |
7672d0b5 EP |
81 | found = 1; |
82 | group = __cbq->group; | |
fd00eecc | 83 | break; |
7672d0b5 EP |
84 | } |
85 | } | |
86 | spin_unlock_bh(&dev->cbdev->queue_lock); | |
87 | ||
88 | if (!found) | |
89 | return -ENODEV; | |
90 | } else { | |
91 | group = __group; | |
92 | } | |
93 | ||
b191ba0d EP |
94 | if (!netlink_has_listeners(dev->nls, group)) |
95 | return -ESRCH; | |
96 | ||
7672d0b5 EP |
97 | size = NLMSG_SPACE(sizeof(*msg) + msg->len); |
98 | ||
99 | skb = alloc_skb(size, gfp_mask); | |
100 | if (!skb) | |
101 | return -ENOMEM; | |
102 | ||
103 | nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh)); | |
104 | ||
105 | data = NLMSG_DATA(nlh); | |
106 | ||
107 | memcpy(data, msg, sizeof(*data) + msg->len); | |
108 | ||
109 | NETLINK_CB(skb).dst_group = group; | |
110 | ||
b191ba0d | 111 | return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask); |
7672d0b5 EP |
112 | |
113 | nlmsg_failure: | |
114 | kfree_skb(skb); | |
115 | return -EINVAL; | |
116 | } | |
deb0e9b2 | 117 | EXPORT_SYMBOL_GPL(cn_netlink_send); |
7672d0b5 EP |
118 | |
119 | /* | |
120 | * Callback helper - queues work and setup destructor for given data. | |
121 | */ | |
f1489cfb | 122 | static int cn_call_callback(struct sk_buff *skb) |
7672d0b5 | 123 | { |
05e52dd7 | 124 | struct cn_callback_entry *__cbq, *__new_cbq; |
7672d0b5 | 125 | struct cn_dev *dev = &cdev; |
293500a2 | 126 | struct cn_msg *msg = NLMSG_DATA(nlmsg_hdr(skb)); |
acd042bb | 127 | int err = -ENODEV; |
7672d0b5 EP |
128 | |
129 | spin_lock_bh(&dev->cbdev->queue_lock); | |
130 | list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) { | |
acd042bb | 131 | if (cn_cb_equal(&__cbq->id.id, &msg->id)) { |
a240d9f1 | 132 | if (likely(!work_pending(&__cbq->work) && |
f1489cfb | 133 | __cbq->data.skb == NULL)) { |
293500a2 | 134 | __cbq->data.skb = skb; |
7672d0b5 | 135 | |
1a5645bc | 136 | if (queue_cn_work(__cbq, &__cbq->work)) |
acd042bb | 137 | err = 0; |
134d99e3 LZ |
138 | else |
139 | err = -EINVAL; | |
7672d0b5 | 140 | } else { |
acd042bb | 141 | struct cn_callback_data *d; |
1a5645bc | 142 | |
05e52dd7 PR |
143 | err = -ENOMEM; |
144 | __new_cbq = kzalloc(sizeof(struct cn_callback_entry), GFP_ATOMIC); | |
145 | if (__new_cbq) { | |
146 | d = &__new_cbq->data; | |
293500a2 | 147 | d->skb = skb; |
acd042bb | 148 | d->callback = __cbq->data.callback; |
05e52dd7 | 149 | d->free = __new_cbq; |
acd042bb | 150 | |
1a5645bc FW |
151 | __new_cbq->pdev = __cbq->pdev; |
152 | ||
05e52dd7 | 153 | INIT_WORK(&__new_cbq->work, |
a240d9f1 | 154 | &cn_queue_wrapper); |
05e52dd7 | 155 | |
1a5645bc | 156 | if (queue_cn_work(__new_cbq, |
05e52dd7 | 157 | &__new_cbq->work)) |
acd042bb EP |
158 | err = 0; |
159 | else { | |
05e52dd7 | 160 | kfree(__new_cbq); |
acd042bb EP |
161 | err = -EINVAL; |
162 | } | |
05e52dd7 | 163 | } |
7672d0b5 EP |
164 | } |
165 | break; | |
166 | } | |
167 | } | |
168 | spin_unlock_bh(&dev->cbdev->queue_lock); | |
169 | ||
acd042bb | 170 | return err; |
7672d0b5 EP |
171 | } |
172 | ||
7672d0b5 EP |
173 | /* |
174 | * Main netlink receiving function. | |
175 | * | |
00f5e06c | 176 | * It checks skb, netlink header and msg sizes, and calls callback helper. |
7672d0b5 EP |
177 | */ |
178 | static void cn_rx_skb(struct sk_buff *__skb) | |
179 | { | |
180 | struct nlmsghdr *nlh; | |
7672d0b5 EP |
181 | int err; |
182 | struct sk_buff *skb; | |
183 | ||
184 | skb = skb_get(__skb); | |
185 | ||
186 | if (skb->len >= NLMSG_SPACE(0)) { | |
b529ccf2 | 187 | nlh = nlmsg_hdr(skb); |
7672d0b5 EP |
188 | |
189 | if (nlh->nlmsg_len < sizeof(struct cn_msg) || | |
190 | skb->len < nlh->nlmsg_len || | |
191 | nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) { | |
192 | kfree_skb(skb); | |
6cf92e98 | 193 | return; |
7672d0b5 EP |
194 | } |
195 | ||
f1489cfb | 196 | err = cn_call_callback(skb); |
7672d0b5 EP |
197 | if (err < 0) |
198 | kfree_skb(skb); | |
199 | } | |
7672d0b5 EP |
200 | } |
201 | ||
7672d0b5 EP |
202 | /* |
203 | * Callback add routing - adds callback with given ID and name. | |
204 | * If there is registered callback with the same ID it will not be added. | |
205 | * | |
206 | * May sleep. | |
207 | */ | |
0741241c | 208 | int cn_add_callback(struct cb_id *id, char *name, |
7069331d | 209 | void (*callback)(struct cn_msg *, struct netlink_skb_parms *)) |
7672d0b5 EP |
210 | { |
211 | int err; | |
212 | struct cn_dev *dev = &cdev; | |
7672d0b5 | 213 | |
d6cc7f1a EP |
214 | if (!cn_already_initialized) |
215 | return -EAGAIN; | |
216 | ||
acd042bb EP |
217 | err = cn_queue_add_callback(dev->cbdev, name, id, callback); |
218 | if (err) | |
7672d0b5 | 219 | return err; |
7672d0b5 | 220 | |
7672d0b5 EP |
221 | return 0; |
222 | } | |
deb0e9b2 | 223 | EXPORT_SYMBOL_GPL(cn_add_callback); |
7672d0b5 EP |
224 | |
225 | /* | |
226 | * Callback remove routing - removes callback | |
227 | * with given ID. | |
228 | * If there is no registered callback with given | |
229 | * ID nothing happens. | |
230 | * | |
231 | * May sleep while waiting for reference counter to become zero. | |
232 | */ | |
233 | void cn_del_callback(struct cb_id *id) | |
234 | { | |
235 | struct cn_dev *dev = &cdev; | |
236 | ||
237 | cn_queue_del_callback(dev->cbdev, id); | |
7672d0b5 | 238 | } |
deb0e9b2 | 239 | EXPORT_SYMBOL_GPL(cn_del_callback); |
7672d0b5 | 240 | |
a0a61a60 LZ |
241 | static int cn_proc_show(struct seq_file *m, void *v) |
242 | { | |
243 | struct cn_queue_dev *dev = cdev.cbdev; | |
244 | struct cn_callback_entry *cbq; | |
245 | ||
246 | seq_printf(m, "Name ID\n"); | |
247 | ||
248 | spin_lock_bh(&dev->queue_lock); | |
249 | ||
250 | list_for_each_entry(cbq, &dev->queue_list, callback_entry) { | |
251 | seq_printf(m, "%-15s %u:%u\n", | |
252 | cbq->id.name, | |
253 | cbq->id.id.idx, | |
254 | cbq->id.id.val); | |
255 | } | |
256 | ||
257 | spin_unlock_bh(&dev->queue_lock); | |
258 | ||
259 | return 0; | |
260 | } | |
261 | ||
262 | static int cn_proc_open(struct inode *inode, struct file *file) | |
263 | { | |
264 | return single_open(file, cn_proc_show, NULL); | |
265 | } | |
266 | ||
267 | static const struct file_operations cn_file_ops = { | |
268 | .owner = THIS_MODULE, | |
269 | .open = cn_proc_open, | |
270 | .read = seq_read, | |
271 | .llseek = seq_lseek, | |
272 | .release = single_release | |
273 | }; | |
274 | ||
d6cc7f1a | 275 | static int __devinit cn_init(void) |
7672d0b5 EP |
276 | { |
277 | struct cn_dev *dev = &cdev; | |
7672d0b5 | 278 | |
cd40b7d3 | 279 | dev->input = cn_rx_skb; |
7672d0b5 | 280 | |
b4b51029 | 281 | dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR, |
7672d0b5 | 282 | CN_NETLINK_USERS + 0xf, |
af65bdfc | 283 | dev->input, NULL, THIS_MODULE); |
7672d0b5 EP |
284 | if (!dev->nls) |
285 | return -EIO; | |
286 | ||
287 | dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls); | |
288 | if (!dev->cbdev) { | |
b7c6ba6e | 289 | netlink_kernel_release(dev->nls); |
7672d0b5 EP |
290 | return -EINVAL; |
291 | } | |
1a5645bc | 292 | |
d6cc7f1a | 293 | cn_already_initialized = 1; |
7672d0b5 | 294 | |
a0a61a60 LZ |
295 | proc_net_fops_create(&init_net, "connector", S_IRUGO, &cn_file_ops); |
296 | ||
7672d0b5 EP |
297 | return 0; |
298 | } | |
299 | ||
d6cc7f1a | 300 | static void __devexit cn_fini(void) |
7672d0b5 EP |
301 | { |
302 | struct cn_dev *dev = &cdev; | |
303 | ||
304 | cn_already_initialized = 0; | |
305 | ||
a0a61a60 LZ |
306 | proc_net_remove(&init_net, "connector"); |
307 | ||
7672d0b5 | 308 | cn_queue_free_dev(dev->cbdev); |
b7c6ba6e | 309 | netlink_kernel_release(dev->nls); |
7672d0b5 EP |
310 | } |
311 | ||
d6cc7f1a | 312 | subsys_initcall(cn_init); |
7672d0b5 | 313 | module_exit(cn_fini); |