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>
32 MODULE_LICENSE("GPL");
33 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
34 MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
36 static u32 cn_idx = CN_IDX_CONNECTOR;
37 static u32 cn_val = CN_VAL_CONNECTOR;
39 module_param(cn_idx, uint, 0);
40 module_param(cn_val, uint, 0);
41 MODULE_PARM_DESC(cn_idx, "Connector's main device idx.");
42 MODULE_PARM_DESC(cn_val, "Connector's main device val.");
44 static DECLARE_MUTEX(notify_lock);
45 static LIST_HEAD(notify_list);
47 static struct cn_dev cdev;
49 int cn_already_initialized = 0;
52 * msg->seq and msg->ack are used to determine message genealogy.
53 * When someone sends message it puts there locally unique sequence
54 * and random acknowledge numbers. Sequence number may be copied into
55 * nlmsghdr->nlmsg_seq too.
57 * Sequence number is incremented with each message to be sent.
59 * If we expect reply to our message then the sequence number in
60 * received message MUST be the same as in original message, and
61 * acknowledge number MUST be the same + 1.
63 * If we receive a message and its sequence number is not equal to the
64 * one we are expecting then it is a new message.
66 * If we receive a message and its sequence number is the same as one
67 * we are expecting but it's acknowledgement number is not equal to
68 * the acknowledgement number in the original message + 1, then it is
72 int cn_netlink_send(struct cn_msg *msg, u32 __group,
73 unsigned int __nocast 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 size = NLMSG_SPACE(sizeof(*msg) + msg->len);
103 skb = alloc_skb(size, gfp_mask);
107 nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh));
109 data = NLMSG_DATA(nlh);
111 memcpy(data, msg, sizeof(*data) + msg->len);
113 NETLINK_CB(skb).dst_group = group;
115 netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
125 * Callback helper - queues work and setup destructor for given data.
127 static int cn_call_callback(struct cn_msg *msg, void (*destruct_data)(void *), void *data)
129 struct cn_callback_entry *__cbq;
130 struct cn_dev *dev = &cdev;
133 spin_lock_bh(&dev->cbdev->queue_lock);
134 list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
135 if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
136 if (likely(!test_bit(0, &__cbq->work.pending) &&
137 __cbq->data.ddata == NULL)) {
138 __cbq->data.callback_priv = msg;
140 __cbq->data.ddata = data;
141 __cbq->data.destruct_data = destruct_data;
143 if (queue_work(dev->cbdev->cn_queue,
147 struct work_struct *w;
148 struct cn_callback_data *d;
150 w = kzalloc(sizeof(*w) + sizeof(*d), GFP_ATOMIC);
152 d = (struct cn_callback_data *)(w+1);
154 d->callback_priv = msg;
155 d->callback = __cbq->data.callback;
157 d->destruct_data = destruct_data;
160 INIT_LIST_HEAD(&w->entry);
162 w->func = &cn_queue_wrapper;
164 init_timer(&w->timer);
166 if (queue_work(dev->cbdev->cn_queue, w))
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 = (struct nlmsghdr *)skb->data;
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);
240 * Netlink socket input callback - dequeues the skbs and calls the
241 * main netlink receiving function.
243 static void cn_input(struct sock *sk, int len)
247 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL)
252 * Notification routing.
254 * Gets id and checks if there are notification request for it's idx
255 * and val. If there are such requests notify the listeners with the
256 * given notify event.
259 static void cn_notify(struct cb_id *id, u32 notify_event)
261 struct cn_ctl_entry *ent;
264 list_for_each_entry(ent, ¬ify_list, notify_entry) {
266 struct cn_notify_req *req;
267 struct cn_ctl_msg *ctl = ent->msg;
268 int idx_found, val_found;
270 idx_found = val_found = 0;
272 req = (struct cn_notify_req *)ctl->data;
273 for (i = 0; i < ctl->idx_notify_num; ++i, ++req) {
274 if (id->idx >= req->first &&
275 id->idx < req->first + req->range) {
281 for (i = 0; i < ctl->val_notify_num; ++i, ++req) {
282 if (id->val >= req->first &&
283 id->val < req->first + req->range) {
289 if (idx_found && val_found) {
290 struct cn_msg m = { .ack = notify_event, };
292 memcpy(&m.id, id, sizeof(m.id));
293 cn_netlink_send(&m, ctl->group, GFP_KERNEL);
300 * Callback add routing - adds callback with given ID and name.
301 * If there is registered callback with the same ID it will not be added.
305 int cn_add_callback(struct cb_id *id, char *name, void (*callback)(void *))
308 struct cn_dev *dev = &cdev;
310 err = cn_queue_add_callback(dev->cbdev, name, id, callback);
320 * Callback remove routing - removes callback
322 * If there is no registered callback with given
323 * ID nothing happens.
325 * May sleep while waiting for reference counter to become zero.
327 void cn_del_callback(struct cb_id *id)
329 struct cn_dev *dev = &cdev;
331 cn_queue_del_callback(dev->cbdev, id);
336 * Checks two connector's control messages to be the same.
337 * Returns 1 if they are the same or if the first one is corrupted.
339 static int cn_ctl_msg_equals(struct cn_ctl_msg *m1, struct cn_ctl_msg *m2)
342 struct cn_notify_req *req1, *req2;
344 if (m1->idx_notify_num != m2->idx_notify_num)
347 if (m1->val_notify_num != m2->val_notify_num)
350 if (m1->len != m2->len)
353 if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) !=
357 req1 = (struct cn_notify_req *)m1->data;
358 req2 = (struct cn_notify_req *)m2->data;
360 for (i = 0; i < m1->idx_notify_num; ++i) {
361 if (req1->first != req2->first || req1->range != req2->range)
367 for (i = 0; i < m1->val_notify_num; ++i) {
368 if (req1->first != req2->first || req1->range != req2->range)
378 * Main connector device's callback.
380 * Used for notification of a request's processing.
382 static void cn_callback(void *data)
384 struct cn_msg *msg = data;
385 struct cn_ctl_msg *ctl;
386 struct cn_ctl_entry *ent;
389 if (msg->len < sizeof(*ctl))
392 ctl = (struct cn_ctl_msg *)msg->data;
394 size = (sizeof(*ctl) + ((ctl->idx_notify_num +
395 ctl->val_notify_num) *
396 sizeof(struct cn_notify_req)));
398 if (msg->len != size)
401 if (ctl->len + sizeof(*ctl) != msg->len)
405 * Remove notification.
407 if (ctl->group == 0) {
408 struct cn_ctl_entry *n;
411 list_for_each_entry_safe(ent, n, ¬ify_list, notify_entry) {
412 if (cn_ctl_msg_equals(ent->msg, ctl)) {
413 list_del(&ent->notify_entry);
422 size += sizeof(*ent);
424 ent = kzalloc(size, GFP_KERNEL);
428 ent->msg = (struct cn_ctl_msg *)(ent + 1);
430 memcpy(ent->msg, ctl, size - sizeof(*ent));
433 list_add(&ent->notify_entry, ¬ify_list);
437 static int __init cn_init(void)
439 struct cn_dev *dev = &cdev;
442 dev->input = cn_input;
443 dev->id.idx = cn_idx;
444 dev->id.val = cn_val;
446 dev->nls = netlink_kernel_create(NETLINK_CONNECTOR,
447 CN_NETLINK_USERS + 0xf,
448 dev->input, THIS_MODULE);
452 dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
454 if (dev->nls->sk_socket)
455 sock_release(dev->nls->sk_socket);
459 err = cn_add_callback(&dev->id, "connector", &cn_callback);
461 cn_queue_free_dev(dev->cbdev);
462 if (dev->nls->sk_socket)
463 sock_release(dev->nls->sk_socket);
467 cn_already_initialized = 1;
472 static void __exit cn_fini(void)
474 struct cn_dev *dev = &cdev;
476 cn_already_initialized = 0;
478 cn_del_callback(&dev->id);
479 cn_queue_free_dev(dev->cbdev);
480 if (dev->nls->sk_socket)
481 sock_release(dev->nls->sk_socket);
484 module_init(cn_init);
485 module_exit(cn_fini);
487 EXPORT_SYMBOL_GPL(cn_add_callback);
488 EXPORT_SYMBOL_GPL(cn_del_callback);
489 EXPORT_SYMBOL_GPL(cn_netlink_send);