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Commit | Line | Data |
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7672d0b5 | 1 | /* |
f3c48ecc | 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 | ||
d2af686c | 22 | #include <linux/compiler.h> |
7672d0b5 EP |
23 | #include <linux/kernel.h> |
24 | #include <linux/module.h> | |
25 | #include <linux/list.h> | |
26 | #include <linux/skbuff.h> | |
9631d79e | 27 | #include <net/netlink.h> |
7672d0b5 EP |
28 | #include <linux/moduleparam.h> |
29 | #include <linux/connector.h> | |
5a0e3ad6 | 30 | #include <linux/slab.h> |
8ed965d6 | 31 | #include <linux/mutex.h> |
a0a61a60 LZ |
32 | #include <linux/proc_fs.h> |
33 | #include <linux/spinlock.h> | |
7672d0b5 EP |
34 | |
35 | #include <net/sock.h> | |
36 | ||
37 | MODULE_LICENSE("GPL"); | |
acb9c1b2 | 38 | MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>"); |
7672d0b5 | 39 | MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector."); |
3700c3c2 | 40 | MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_CONNECTOR); |
7672d0b5 | 41 | |
7672d0b5 EP |
42 | static struct cn_dev cdev; |
43 | ||
78374676 | 44 | static int cn_already_initialized; |
7672d0b5 EP |
45 | |
46 | /* | |
34470e0b DF |
47 | * Sends mult (multiple) cn_msg at a time. |
48 | * | |
7672d0b5 EP |
49 | * msg->seq and msg->ack are used to determine message genealogy. |
50 | * When someone sends message it puts there locally unique sequence | |
51 | * and random acknowledge numbers. Sequence number may be copied into | |
52 | * nlmsghdr->nlmsg_seq too. | |
53 | * | |
54 | * Sequence number is incremented with each message to be sent. | |
55 | * | |
ac8f7330 | 56 | * If we expect a reply to our message then the sequence number in |
7672d0b5 EP |
57 | * received message MUST be the same as in original message, and |
58 | * acknowledge number MUST be the same + 1. | |
59 | * | |
60 | * If we receive a message and its sequence number is not equal to the | |
61 | * one we are expecting then it is a new message. | |
62 | * | |
63 | * If we receive a message and its sequence number is the same as one | |
64 | * we are expecting but it's acknowledgement number is not equal to | |
65 | * the acknowledgement number in the original message + 1, then it is | |
66 | * a new message. | |
67 | * | |
34470e0b DF |
68 | * If msg->len != len, then additional cn_msg messages are expected following |
69 | * the first msg. | |
70 | * | |
ac8f7330 DF |
71 | * The message is sent to, the portid if given, the group if given, both if |
72 | * both, or if both are zero then the group is looked up and sent there. | |
7672d0b5 | 73 | */ |
34470e0b | 74 | int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid, u32 __group, |
ac8f7330 | 75 | gfp_t gfp_mask) |
7672d0b5 EP |
76 | { |
77 | struct cn_callback_entry *__cbq; | |
78 | unsigned int size; | |
79 | struct sk_buff *skb; | |
80 | struct nlmsghdr *nlh; | |
81 | struct cn_msg *data; | |
82 | struct cn_dev *dev = &cdev; | |
83 | u32 group = 0; | |
84 | int found = 0; | |
85 | ||
ac8f7330 DF |
86 | if (portid || __group) { |
87 | group = __group; | |
88 | } else { | |
7672d0b5 EP |
89 | spin_lock_bh(&dev->cbdev->queue_lock); |
90 | list_for_each_entry(__cbq, &dev->cbdev->queue_list, | |
91 | callback_entry) { | |
acd042bb | 92 | if (cn_cb_equal(&__cbq->id.id, &msg->id)) { |
7672d0b5 EP |
93 | found = 1; |
94 | group = __cbq->group; | |
fd00eecc | 95 | break; |
7672d0b5 EP |
96 | } |
97 | } | |
98 | spin_unlock_bh(&dev->cbdev->queue_lock); | |
99 | ||
100 | if (!found) | |
101 | return -ENODEV; | |
7672d0b5 EP |
102 | } |
103 | ||
ac8f7330 | 104 | if (!portid && !netlink_has_listeners(dev->nls, group)) |
b191ba0d EP |
105 | return -ESRCH; |
106 | ||
34470e0b | 107 | size = sizeof(*msg) + len; |
7672d0b5 | 108 | |
9631d79e | 109 | skb = nlmsg_new(size, gfp_mask); |
7672d0b5 EP |
110 | if (!skb) |
111 | return -ENOMEM; | |
112 | ||
9631d79e | 113 | nlh = nlmsg_put(skb, 0, msg->seq, NLMSG_DONE, size, 0); |
85c93166 JMC |
114 | if (!nlh) { |
115 | kfree_skb(skb); | |
116 | return -EMSGSIZE; | |
117 | } | |
7672d0b5 | 118 | |
85c93166 | 119 | data = nlmsg_data(nlh); |
7672d0b5 | 120 | |
ac73bf50 | 121 | memcpy(data, msg, size); |
7672d0b5 EP |
122 | |
123 | NETLINK_CB(skb).dst_group = group; | |
124 | ||
ac8f7330 DF |
125 | if (group) |
126 | return netlink_broadcast(dev->nls, skb, portid, group, | |
127 | gfp_mask); | |
d0164adc MG |
128 | return netlink_unicast(dev->nls, skb, portid, |
129 | !gfpflags_allow_blocking(gfp_mask)); | |
7672d0b5 | 130 | } |
34470e0b DF |
131 | EXPORT_SYMBOL_GPL(cn_netlink_send_mult); |
132 | ||
133 | /* same as cn_netlink_send_mult except msg->len is used for len */ | |
134 | int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 __group, | |
135 | gfp_t gfp_mask) | |
136 | { | |
137 | return cn_netlink_send_mult(msg, msg->len, portid, __group, gfp_mask); | |
138 | } | |
deb0e9b2 | 139 | EXPORT_SYMBOL_GPL(cn_netlink_send); |
7672d0b5 EP |
140 | |
141 | /* | |
142 | * Callback helper - queues work and setup destructor for given data. | |
143 | */ | |
f1489cfb | 144 | static int cn_call_callback(struct sk_buff *skb) |
7672d0b5 | 145 | { |
a30cfa47 | 146 | struct nlmsghdr *nlh; |
04f482fa | 147 | struct cn_callback_entry *i, *cbq = NULL; |
7672d0b5 | 148 | struct cn_dev *dev = &cdev; |
9631d79e | 149 | struct cn_msg *msg = nlmsg_data(nlmsg_hdr(skb)); |
04f482fa | 150 | struct netlink_skb_parms *nsp = &NETLINK_CB(skb); |
acd042bb | 151 | int err = -ENODEV; |
7672d0b5 | 152 | |
a30cfa47 DF |
153 | /* verify msg->len is within skb */ |
154 | nlh = nlmsg_hdr(skb); | |
155 | if (nlh->nlmsg_len < NLMSG_HDRLEN + sizeof(struct cn_msg) + msg->len) | |
156 | return -EINVAL; | |
157 | ||
7672d0b5 | 158 | spin_lock_bh(&dev->cbdev->queue_lock); |
04f482fa PM |
159 | list_for_each_entry(i, &dev->cbdev->queue_list, callback_entry) { |
160 | if (cn_cb_equal(&i->id.id, &msg->id)) { | |
e65f7ee3 | 161 | refcount_inc(&i->refcnt); |
04f482fa | 162 | cbq = i; |
7672d0b5 EP |
163 | break; |
164 | } | |
165 | } | |
166 | spin_unlock_bh(&dev->cbdev->queue_lock); | |
167 | ||
04f482fa PM |
168 | if (cbq != NULL) { |
169 | cbq->callback(msg, nsp); | |
170 | kfree_skb(skb); | |
171 | cn_queue_release_callback(cbq); | |
0e087858 | 172 | err = 0; |
04f482fa PM |
173 | } |
174 | ||
acd042bb | 175 | return err; |
7672d0b5 EP |
176 | } |
177 | ||
7672d0b5 EP |
178 | /* |
179 | * Main netlink receiving function. | |
180 | * | |
00f5e06c | 181 | * It checks skb, netlink header and msg sizes, and calls callback helper. |
7672d0b5 | 182 | */ |
55285bf0 | 183 | static void cn_rx_skb(struct sk_buff *skb) |
7672d0b5 EP |
184 | { |
185 | struct nlmsghdr *nlh; | |
162b2bed | 186 | int len, err; |
7672d0b5 | 187 | |
9631d79e | 188 | if (skb->len >= NLMSG_HDRLEN) { |
b529ccf2 | 189 | nlh = nlmsg_hdr(skb); |
162b2bed | 190 | len = nlmsg_len(nlh); |
7672d0b5 | 191 | |
162b2bed | 192 | if (len < (int)sizeof(struct cn_msg) || |
7672d0b5 | 193 | skb->len < nlh->nlmsg_len || |
55285bf0 | 194 | len > CONNECTOR_MAX_MSG_SIZE) |
6cf92e98 | 195 | return; |
7672d0b5 | 196 | |
55285bf0 | 197 | err = cn_call_callback(skb_get(skb)); |
7672d0b5 EP |
198 | if (err < 0) |
199 | kfree_skb(skb); | |
200 | } | |
7672d0b5 EP |
201 | } |
202 | ||
7672d0b5 EP |
203 | /* |
204 | * Callback add routing - adds callback with given ID and name. | |
205 | * If there is registered callback with the same ID it will not be added. | |
206 | * | |
207 | * May sleep. | |
208 | */ | |
008536e8 | 209 | int cn_add_callback(struct cb_id *id, const char *name, |
f3c48ecc VI |
210 | void (*callback)(struct cn_msg *, |
211 | struct netlink_skb_parms *)) | |
7672d0b5 EP |
212 | { |
213 | int err; | |
214 | struct cn_dev *dev = &cdev; | |
7672d0b5 | 215 | |
d6cc7f1a EP |
216 | if (!cn_already_initialized) |
217 | return -EAGAIN; | |
218 | ||
acd042bb EP |
219 | err = cn_queue_add_callback(dev->cbdev, name, id, callback); |
220 | if (err) | |
7672d0b5 | 221 | return err; |
7672d0b5 | 222 | |
7672d0b5 EP |
223 | return 0; |
224 | } | |
deb0e9b2 | 225 | EXPORT_SYMBOL_GPL(cn_add_callback); |
7672d0b5 EP |
226 | |
227 | /* | |
228 | * Callback remove routing - removes callback | |
229 | * with given ID. | |
230 | * If there is no registered callback with given | |
231 | * ID nothing happens. | |
232 | * | |
233 | * May sleep while waiting for reference counter to become zero. | |
234 | */ | |
235 | void cn_del_callback(struct cb_id *id) | |
236 | { | |
237 | struct cn_dev *dev = &cdev; | |
238 | ||
239 | cn_queue_del_callback(dev->cbdev, id); | |
7672d0b5 | 240 | } |
deb0e9b2 | 241 | EXPORT_SYMBOL_GPL(cn_del_callback); |
7672d0b5 | 242 | |
d2af686c | 243 | static int __maybe_unused cn_proc_show(struct seq_file *m, void *v) |
a0a61a60 LZ |
244 | { |
245 | struct cn_queue_dev *dev = cdev.cbdev; | |
246 | struct cn_callback_entry *cbq; | |
247 | ||
248 | seq_printf(m, "Name ID\n"); | |
249 | ||
250 | spin_lock_bh(&dev->queue_lock); | |
251 | ||
252 | list_for_each_entry(cbq, &dev->queue_list, callback_entry) { | |
253 | seq_printf(m, "%-15s %u:%u\n", | |
254 | cbq->id.name, | |
255 | cbq->id.id.idx, | |
256 | cbq->id.id.val); | |
257 | } | |
258 | ||
259 | spin_unlock_bh(&dev->queue_lock); | |
260 | ||
261 | return 0; | |
262 | } | |
263 | ||
a31f2d17 PNA |
264 | static struct cn_dev cdev = { |
265 | .input = cn_rx_skb, | |
266 | }; | |
267 | ||
0fe763c5 | 268 | static int cn_init(void) |
7672d0b5 EP |
269 | { |
270 | struct cn_dev *dev = &cdev; | |
a31f2d17 PNA |
271 | struct netlink_kernel_cfg cfg = { |
272 | .groups = CN_NETLINK_USERS + 0xf, | |
273 | .input = dev->input, | |
274 | }; | |
7672d0b5 | 275 | |
9f00d977 | 276 | dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR, &cfg); |
7672d0b5 EP |
277 | if (!dev->nls) |
278 | return -EIO; | |
279 | ||
280 | dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls); | |
281 | if (!dev->cbdev) { | |
b7c6ba6e | 282 | netlink_kernel_release(dev->nls); |
7672d0b5 EP |
283 | return -EINVAL; |
284 | } | |
1a5645bc | 285 | |
d6cc7f1a | 286 | cn_already_initialized = 1; |
7672d0b5 | 287 | |
3f3942ac | 288 | proc_create_single("connector", S_IRUGO, init_net.proc_net, cn_proc_show); |
a0a61a60 | 289 | |
7672d0b5 EP |
290 | return 0; |
291 | } | |
292 | ||
0fe763c5 | 293 | static void cn_fini(void) |
7672d0b5 EP |
294 | { |
295 | struct cn_dev *dev = &cdev; | |
296 | ||
297 | cn_already_initialized = 0; | |
298 | ||
ece31ffd | 299 | remove_proc_entry("connector", init_net.proc_net); |
a0a61a60 | 300 | |
7672d0b5 | 301 | cn_queue_free_dev(dev->cbdev); |
b7c6ba6e | 302 | netlink_kernel_release(dev->nls); |
7672d0b5 EP |
303 | } |
304 | ||
d6cc7f1a | 305 | subsys_initcall(cn_init); |
7672d0b5 | 306 | module_exit(cn_fini); |