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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 | 38 | MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector."); |
3700c3c2 | 39 | MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_CONNECTOR); |
7672d0b5 | 40 | |
7672d0b5 EP |
41 | static struct cn_dev cdev; |
42 | ||
78374676 | 43 | static int cn_already_initialized; |
7672d0b5 EP |
44 | |
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 | */ | |
dd0fc66f | 66 | int cn_netlink_send(struct cn_msg *msg, u32 __group, gfp_t gfp_mask) |
7672d0b5 EP |
67 | { |
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) { | |
acd042bb | 81 | if (cn_cb_equal(&__cbq->id.id, &msg->id)) { |
7672d0b5 EP |
82 | found = 1; |
83 | group = __cbq->group; | |
fd00eecc | 84 | break; |
7672d0b5 EP |
85 | } |
86 | } | |
87 | spin_unlock_bh(&dev->cbdev->queue_lock); | |
88 | ||
89 | if (!found) | |
90 | return -ENODEV; | |
91 | } else { | |
92 | group = __group; | |
93 | } | |
94 | ||
b191ba0d EP |
95 | if (!netlink_has_listeners(dev->nls, group)) |
96 | return -ESRCH; | |
97 | ||
7672d0b5 EP |
98 | size = NLMSG_SPACE(sizeof(*msg) + msg->len); |
99 | ||
100 | skb = alloc_skb(size, gfp_mask); | |
101 | if (!skb) | |
102 | return -ENOMEM; | |
103 | ||
104 | nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh)); | |
105 | ||
106 | data = NLMSG_DATA(nlh); | |
107 | ||
108 | memcpy(data, msg, sizeof(*data) + msg->len); | |
109 | ||
110 | NETLINK_CB(skb).dst_group = group; | |
111 | ||
b191ba0d | 112 | return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask); |
7672d0b5 EP |
113 | |
114 | nlmsg_failure: | |
115 | kfree_skb(skb); | |
116 | return -EINVAL; | |
117 | } | |
deb0e9b2 | 118 | EXPORT_SYMBOL_GPL(cn_netlink_send); |
7672d0b5 EP |
119 | |
120 | /* | |
121 | * Callback helper - queues work and setup destructor for given data. | |
122 | */ | |
f1489cfb | 123 | static int cn_call_callback(struct sk_buff *skb) |
7672d0b5 | 124 | { |
04f482fa | 125 | struct cn_callback_entry *i, *cbq = NULL; |
7672d0b5 | 126 | struct cn_dev *dev = &cdev; |
293500a2 | 127 | struct cn_msg *msg = NLMSG_DATA(nlmsg_hdr(skb)); |
04f482fa | 128 | struct netlink_skb_parms *nsp = &NETLINK_CB(skb); |
acd042bb | 129 | int err = -ENODEV; |
7672d0b5 EP |
130 | |
131 | spin_lock_bh(&dev->cbdev->queue_lock); | |
04f482fa PM |
132 | 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; | |
7672d0b5 EP |
136 | break; |
137 | } | |
138 | } | |
139 | spin_unlock_bh(&dev->cbdev->queue_lock); | |
140 | ||
04f482fa PM |
141 | if (cbq != NULL) { |
142 | cbq->callback(msg, nsp); | |
143 | kfree_skb(skb); | |
144 | cn_queue_release_callback(cbq); | |
0e087858 | 145 | err = 0; |
04f482fa PM |
146 | } |
147 | ||
acd042bb | 148 | return err; |
7672d0b5 EP |
149 | } |
150 | ||
7672d0b5 EP |
151 | /* |
152 | * Main netlink receiving function. | |
153 | * | |
00f5e06c | 154 | * It checks skb, netlink header and msg sizes, and calls callback helper. |
7672d0b5 EP |
155 | */ |
156 | static void cn_rx_skb(struct sk_buff *__skb) | |
157 | { | |
158 | struct nlmsghdr *nlh; | |
7672d0b5 EP |
159 | int err; |
160 | struct sk_buff *skb; | |
161 | ||
162 | skb = skb_get(__skb); | |
163 | ||
164 | if (skb->len >= NLMSG_SPACE(0)) { | |
b529ccf2 | 165 | nlh = nlmsg_hdr(skb); |
7672d0b5 EP |
166 | |
167 | if (nlh->nlmsg_len < sizeof(struct cn_msg) || | |
168 | skb->len < nlh->nlmsg_len || | |
169 | nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) { | |
170 | kfree_skb(skb); | |
6cf92e98 | 171 | return; |
7672d0b5 EP |
172 | } |
173 | ||
f1489cfb | 174 | err = cn_call_callback(skb); |
7672d0b5 EP |
175 | if (err < 0) |
176 | kfree_skb(skb); | |
177 | } | |
7672d0b5 EP |
178 | } |
179 | ||
7672d0b5 EP |
180 | /* |
181 | * Callback add routing - adds callback with given ID and name. | |
182 | * If there is registered callback with the same ID it will not be added. | |
183 | * | |
184 | * May sleep. | |
185 | */ | |
008536e8 | 186 | int cn_add_callback(struct cb_id *id, const char *name, |
7069331d | 187 | void (*callback)(struct cn_msg *, struct netlink_skb_parms *)) |
7672d0b5 EP |
188 | { |
189 | int err; | |
190 | struct cn_dev *dev = &cdev; | |
7672d0b5 | 191 | |
d6cc7f1a EP |
192 | if (!cn_already_initialized) |
193 | return -EAGAIN; | |
194 | ||
acd042bb EP |
195 | err = cn_queue_add_callback(dev->cbdev, name, id, callback); |
196 | if (err) | |
7672d0b5 | 197 | return err; |
7672d0b5 | 198 | |
7672d0b5 EP |
199 | return 0; |
200 | } | |
deb0e9b2 | 201 | EXPORT_SYMBOL_GPL(cn_add_callback); |
7672d0b5 EP |
202 | |
203 | /* | |
204 | * Callback remove routing - removes callback | |
205 | * with given ID. | |
206 | * If there is no registered callback with given | |
207 | * ID nothing happens. | |
208 | * | |
209 | * May sleep while waiting for reference counter to become zero. | |
210 | */ | |
211 | void cn_del_callback(struct cb_id *id) | |
212 | { | |
213 | struct cn_dev *dev = &cdev; | |
214 | ||
215 | cn_queue_del_callback(dev->cbdev, id); | |
7672d0b5 | 216 | } |
deb0e9b2 | 217 | EXPORT_SYMBOL_GPL(cn_del_callback); |
7672d0b5 | 218 | |
a0a61a60 LZ |
219 | static int cn_proc_show(struct seq_file *m, void *v) |
220 | { | |
221 | struct cn_queue_dev *dev = cdev.cbdev; | |
222 | struct cn_callback_entry *cbq; | |
223 | ||
224 | seq_printf(m, "Name ID\n"); | |
225 | ||
226 | spin_lock_bh(&dev->queue_lock); | |
227 | ||
228 | list_for_each_entry(cbq, &dev->queue_list, callback_entry) { | |
229 | seq_printf(m, "%-15s %u:%u\n", | |
230 | cbq->id.name, | |
231 | cbq->id.id.idx, | |
232 | cbq->id.id.val); | |
233 | } | |
234 | ||
235 | spin_unlock_bh(&dev->queue_lock); | |
236 | ||
237 | return 0; | |
238 | } | |
239 | ||
240 | static int cn_proc_open(struct inode *inode, struct file *file) | |
241 | { | |
242 | return single_open(file, cn_proc_show, NULL); | |
243 | } | |
244 | ||
245 | static const struct file_operations cn_file_ops = { | |
246 | .owner = THIS_MODULE, | |
247 | .open = cn_proc_open, | |
248 | .read = seq_read, | |
249 | .llseek = seq_lseek, | |
250 | .release = single_release | |
251 | }; | |
252 | ||
d6cc7f1a | 253 | static int __devinit cn_init(void) |
7672d0b5 EP |
254 | { |
255 | struct cn_dev *dev = &cdev; | |
7672d0b5 | 256 | |
cd40b7d3 | 257 | dev->input = cn_rx_skb; |
7672d0b5 | 258 | |
b4b51029 | 259 | dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR, |
7672d0b5 | 260 | CN_NETLINK_USERS + 0xf, |
af65bdfc | 261 | dev->input, NULL, THIS_MODULE); |
7672d0b5 EP |
262 | if (!dev->nls) |
263 | return -EIO; | |
264 | ||
265 | dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls); | |
266 | if (!dev->cbdev) { | |
b7c6ba6e | 267 | netlink_kernel_release(dev->nls); |
7672d0b5 EP |
268 | return -EINVAL; |
269 | } | |
1a5645bc | 270 | |
d6cc7f1a | 271 | cn_already_initialized = 1; |
7672d0b5 | 272 | |
a0a61a60 LZ |
273 | proc_net_fops_create(&init_net, "connector", S_IRUGO, &cn_file_ops); |
274 | ||
7672d0b5 EP |
275 | return 0; |
276 | } | |
277 | ||
d6cc7f1a | 278 | static void __devexit cn_fini(void) |
7672d0b5 EP |
279 | { |
280 | struct cn_dev *dev = &cdev; | |
281 | ||
282 | cn_already_initialized = 0; | |
283 | ||
a0a61a60 LZ |
284 | proc_net_remove(&init_net, "connector"); |
285 | ||
7672d0b5 | 286 | cn_queue_free_dev(dev->cbdev); |
b7c6ba6e | 287 | netlink_kernel_release(dev->nls); |
7672d0b5 EP |
288 | } |
289 | ||
d6cc7f1a | 290 | subsys_initcall(cn_init); |
7672d0b5 | 291 | module_exit(cn_fini); |