4 * 2004-2005 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
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.
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.
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
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>
29 #include <linux/mutex.h>
33 MODULE_LICENSE("GPL");
34 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
35 MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
37 static u32 cn_idx = CN_IDX_CONNECTOR;
38 static u32 cn_val = CN_VAL_CONNECTOR;
40 module_param(cn_idx, uint, 0);
41 module_param(cn_val, uint, 0);
42 MODULE_PARM_DESC(cn_idx, "Connector's main device idx.");
43 MODULE_PARM_DESC(cn_val, "Connector's main device val.");
45 static DEFINE_MUTEX(notify_lock);
46 static LIST_HEAD(notify_list);
48 static struct cn_dev cdev;
50 int cn_already_initialized = 0;
53 * msg->seq and msg->ack are used to determine message genealogy.
54 * When someone sends message it puts there locally unique sequence
55 * and random acknowledge numbers. Sequence number may be copied into
56 * nlmsghdr->nlmsg_seq too.
58 * Sequence number is incremented with each message to be sent.
60 * If we expect reply to our message then the sequence number in
61 * received message MUST be the same as in original message, and
62 * acknowledge number MUST be the same + 1.
64 * If we receive a message and its sequence number is not equal to the
65 * one we are expecting then it is a new message.
67 * If we receive a message and its sequence number is the same as one
68 * we are expecting but it's acknowledgement number is not equal to
69 * the acknowledgement number in the original message + 1, then it is
73 int cn_netlink_send(struct cn_msg *msg, u32 __group, gfp_t gfp_mask)
75 struct cn_callback_entry *__cbq;
80 struct cn_dev *dev = &cdev;
85 spin_lock_bh(&dev->cbdev->queue_lock);
86 list_for_each_entry(__cbq, &dev->cbdev->queue_list,
88 if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
93 spin_unlock_bh(&dev->cbdev->queue_lock);
101 if (!netlink_has_listeners(dev->nls, group))
104 size = NLMSG_SPACE(sizeof(*msg) + msg->len);
106 skb = alloc_skb(size, gfp_mask);
110 nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh));
112 data = NLMSG_DATA(nlh);
114 memcpy(data, msg, sizeof(*data) + msg->len);
116 NETLINK_CB(skb).dst_group = group;
118 return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
124 EXPORT_SYMBOL_GPL(cn_netlink_send);
127 * Callback helper - queues work and setup destructor for given data.
129 static int cn_call_callback(struct cn_msg *msg, void (*destruct_data)(void *), void *data)
131 struct cn_callback_entry *__cbq, *__new_cbq;
132 struct cn_dev *dev = &cdev;
135 spin_lock_bh(&dev->cbdev->queue_lock);
136 list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
137 if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
138 if (likely(!work_pending(&__cbq->work) &&
139 __cbq->data.ddata == NULL)) {
140 __cbq->data.callback_priv = msg;
142 __cbq->data.ddata = data;
143 __cbq->data.destruct_data = destruct_data;
145 if (queue_work(dev->cbdev->cn_queue,
151 struct cn_callback_data *d;
154 __new_cbq = kzalloc(sizeof(struct cn_callback_entry), GFP_ATOMIC);
156 d = &__new_cbq->data;
157 d->callback_priv = msg;
158 d->callback = __cbq->data.callback;
160 d->destruct_data = destruct_data;
163 INIT_WORK(&__new_cbq->work,
166 if (queue_work(dev->cbdev->cn_queue,
178 spin_unlock_bh(&dev->cbdev->queue_lock);
184 * Skb receive helper - checks skb and msg size and calls callback
187 static int __cn_rx_skb(struct sk_buff *skb, struct nlmsghdr *nlh)
189 u32 pid, uid, seq, group;
192 pid = NETLINK_CREDS(skb)->pid;
193 uid = NETLINK_CREDS(skb)->uid;
194 seq = nlh->nlmsg_seq;
195 group = NETLINK_CB((skb)).dst_group;
196 msg = NLMSG_DATA(nlh);
198 return cn_call_callback(msg, (void (*)(void *))kfree_skb, skb);
202 * Main netlink receiving function.
204 * It checks skb and netlink header sizes and calls the skb receive
205 * helper with a shared skb.
207 static void cn_rx_skb(struct sk_buff *__skb)
209 struct nlmsghdr *nlh;
214 skb = skb_get(__skb);
216 if (skb->len >= NLMSG_SPACE(0)) {
217 nlh = nlmsg_hdr(skb);
219 if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
220 skb->len < nlh->nlmsg_len ||
221 nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
226 len = NLMSG_ALIGN(nlh->nlmsg_len);
230 err = __cn_rx_skb(skb, nlh);
237 * Notification routing.
239 * Gets id and checks if there are notification request for it's idx
240 * and val. If there are such requests notify the listeners with the
241 * given notify event.
244 static void cn_notify(struct cb_id *id, u32 notify_event)
246 struct cn_ctl_entry *ent;
248 mutex_lock(¬ify_lock);
249 list_for_each_entry(ent, ¬ify_list, notify_entry) {
251 struct cn_notify_req *req;
252 struct cn_ctl_msg *ctl = ent->msg;
253 int idx_found, val_found;
255 idx_found = val_found = 0;
257 req = (struct cn_notify_req *)ctl->data;
258 for (i = 0; i < ctl->idx_notify_num; ++i, ++req) {
259 if (id->idx >= req->first &&
260 id->idx < req->first + req->range) {
266 for (i = 0; i < ctl->val_notify_num; ++i, ++req) {
267 if (id->val >= req->first &&
268 id->val < req->first + req->range) {
274 if (idx_found && val_found) {
275 struct cn_msg m = { .ack = notify_event, };
277 memcpy(&m.id, id, sizeof(m.id));
278 cn_netlink_send(&m, ctl->group, GFP_KERNEL);
281 mutex_unlock(¬ify_lock);
285 * Callback add routing - adds callback with given ID and name.
286 * If there is registered callback with the same ID it will not be added.
290 int cn_add_callback(struct cb_id *id, char *name, void (*callback)(void *))
293 struct cn_dev *dev = &cdev;
295 if (!cn_already_initialized)
298 err = cn_queue_add_callback(dev->cbdev, name, id, callback);
306 EXPORT_SYMBOL_GPL(cn_add_callback);
309 * Callback remove routing - removes callback
311 * If there is no registered callback with given
312 * ID nothing happens.
314 * May sleep while waiting for reference counter to become zero.
316 void cn_del_callback(struct cb_id *id)
318 struct cn_dev *dev = &cdev;
320 cn_queue_del_callback(dev->cbdev, id);
323 EXPORT_SYMBOL_GPL(cn_del_callback);
326 * Checks two connector's control messages to be the same.
327 * Returns 1 if they are the same or if the first one is corrupted.
329 static int cn_ctl_msg_equals(struct cn_ctl_msg *m1, struct cn_ctl_msg *m2)
332 struct cn_notify_req *req1, *req2;
334 if (m1->idx_notify_num != m2->idx_notify_num)
337 if (m1->val_notify_num != m2->val_notify_num)
340 if (m1->len != m2->len)
343 if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) !=
347 req1 = (struct cn_notify_req *)m1->data;
348 req2 = (struct cn_notify_req *)m2->data;
350 for (i = 0; i < m1->idx_notify_num; ++i) {
351 if (req1->first != req2->first || req1->range != req2->range)
357 for (i = 0; i < m1->val_notify_num; ++i) {
358 if (req1->first != req2->first || req1->range != req2->range)
368 * Main connector device's callback.
370 * Used for notification of a request's processing.
372 static void cn_callback(void *data)
374 struct cn_msg *msg = data;
375 struct cn_ctl_msg *ctl;
376 struct cn_ctl_entry *ent;
379 if (msg->len < sizeof(*ctl))
382 ctl = (struct cn_ctl_msg *)msg->data;
384 size = (sizeof(*ctl) + ((ctl->idx_notify_num +
385 ctl->val_notify_num) *
386 sizeof(struct cn_notify_req)));
388 if (msg->len != size)
391 if (ctl->len + sizeof(*ctl) != msg->len)
395 * Remove notification.
397 if (ctl->group == 0) {
398 struct cn_ctl_entry *n;
400 mutex_lock(¬ify_lock);
401 list_for_each_entry_safe(ent, n, ¬ify_list, notify_entry) {
402 if (cn_ctl_msg_equals(ent->msg, ctl)) {
403 list_del(&ent->notify_entry);
407 mutex_unlock(¬ify_lock);
412 size += sizeof(*ent);
414 ent = kzalloc(size, GFP_KERNEL);
418 ent->msg = (struct cn_ctl_msg *)(ent + 1);
420 memcpy(ent->msg, ctl, size - sizeof(*ent));
422 mutex_lock(¬ify_lock);
423 list_add(&ent->notify_entry, ¬ify_list);
424 mutex_unlock(¬ify_lock);
427 static int __devinit cn_init(void)
429 struct cn_dev *dev = &cdev;
432 dev->input = cn_rx_skb;
433 dev->id.idx = cn_idx;
434 dev->id.val = cn_val;
436 dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR,
437 CN_NETLINK_USERS + 0xf,
438 dev->input, NULL, THIS_MODULE);
442 dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
444 if (dev->nls->sk_socket)
445 sock_release(dev->nls->sk_socket);
449 cn_already_initialized = 1;
451 err = cn_add_callback(&dev->id, "connector", &cn_callback);
453 cn_already_initialized = 0;
454 cn_queue_free_dev(dev->cbdev);
455 if (dev->nls->sk_socket)
456 sock_release(dev->nls->sk_socket);
463 static void __devexit cn_fini(void)
465 struct cn_dev *dev = &cdev;
467 cn_already_initialized = 0;
469 cn_del_callback(&dev->id);
470 cn_queue_free_dev(dev->cbdev);
471 if (dev->nls->sk_socket)
472 sock_release(dev->nls->sk_socket);
475 subsys_initcall(cn_init);
476 module_exit(cn_fini);