xref: /linux/drivers/w1/w1_netlink.c (revision 4413e16d9d21673bb5048a2e542f1aaa00015c2e)
1 /*
2  * w1_netlink.c
3  *
4  * Copyright (c) 2003 Evgeniy Polyakov <zbr@ioremap.net>
5  *
6  *
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/slab.h>
23 #include <linux/skbuff.h>
24 #include <linux/netlink.h>
25 #include <linux/connector.h>
26 
27 #include "w1.h"
28 #include "w1_log.h"
29 #include "w1_netlink.h"
30 
31 #if defined(CONFIG_W1_CON) && (defined(CONFIG_CONNECTOR) || (defined(CONFIG_CONNECTOR_MODULE) && defined(CONFIG_W1_MODULE)))
32 void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
33 {
34 	char buf[sizeof(struct cn_msg) + sizeof(struct w1_netlink_msg)];
35 	struct cn_msg *m = (struct cn_msg *)buf;
36 	struct w1_netlink_msg *w = (struct w1_netlink_msg *)(m+1);
37 
38 	memset(buf, 0, sizeof(buf));
39 
40 	m->id.idx = CN_W1_IDX;
41 	m->id.val = CN_W1_VAL;
42 
43 	m->seq = dev->seq++;
44 	m->len = sizeof(struct w1_netlink_msg);
45 
46 	memcpy(w, msg, sizeof(struct w1_netlink_msg));
47 
48 	cn_netlink_send(m, 0, GFP_KERNEL);
49 }
50 
51 static void w1_send_slave(struct w1_master *dev, u64 rn)
52 {
53 	struct cn_msg *msg = dev->priv;
54 	struct w1_netlink_msg *hdr = (struct w1_netlink_msg *)(msg + 1);
55 	struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)(hdr + 1);
56 	int avail;
57 
58 	/* update kernel slave list */
59 	w1_slave_found(dev, rn);
60 
61 	avail = dev->priv_size - cmd->len;
62 
63 	if (avail > 8) {
64 		u64 *data = (void *)(cmd + 1) + cmd->len;
65 
66 		*data = rn;
67 		cmd->len += 8;
68 		hdr->len += 8;
69 		msg->len += 8;
70 		return;
71 	}
72 
73 	msg->ack++;
74 	cn_netlink_send(msg, 0, GFP_KERNEL);
75 
76 	msg->len = sizeof(struct w1_netlink_msg) + sizeof(struct w1_netlink_cmd);
77 	hdr->len = sizeof(struct w1_netlink_cmd);
78 	cmd->len = 0;
79 }
80 
81 static int w1_process_search_command(struct w1_master *dev, struct cn_msg *msg,
82 		unsigned int avail)
83 {
84 	struct w1_netlink_msg *hdr = (struct w1_netlink_msg *)(msg + 1);
85 	struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)(hdr + 1);
86 	int search_type = (cmd->cmd == W1_CMD_ALARM_SEARCH)?W1_ALARM_SEARCH:W1_SEARCH;
87 
88 	dev->priv = msg;
89 	dev->priv_size = avail;
90 
91 	w1_search_process_cb(dev, search_type, w1_send_slave);
92 
93 	msg->ack = 0;
94 	cn_netlink_send(msg, 0, GFP_KERNEL);
95 
96 	dev->priv = NULL;
97 	dev->priv_size = 0;
98 
99 	return 0;
100 }
101 
102 static int w1_send_read_reply(struct cn_msg *msg, struct w1_netlink_msg *hdr,
103 		struct w1_netlink_cmd *cmd)
104 {
105 	void *data;
106 	struct w1_netlink_msg *h;
107 	struct w1_netlink_cmd *c;
108 	struct cn_msg *cm;
109 	int err;
110 
111 	data = kzalloc(sizeof(struct cn_msg) +
112 			sizeof(struct w1_netlink_msg) +
113 			sizeof(struct w1_netlink_cmd) +
114 			cmd->len, GFP_KERNEL);
115 	if (!data)
116 		return -ENOMEM;
117 
118 	cm = (struct cn_msg *)(data);
119 	h = (struct w1_netlink_msg *)(cm + 1);
120 	c = (struct w1_netlink_cmd *)(h + 1);
121 
122 	memcpy(cm, msg, sizeof(struct cn_msg));
123 	memcpy(h, hdr, sizeof(struct w1_netlink_msg));
124 	memcpy(c, cmd, sizeof(struct w1_netlink_cmd));
125 
126 	cm->ack = msg->seq+1;
127 	cm->len = sizeof(struct w1_netlink_msg) +
128 		sizeof(struct w1_netlink_cmd) + cmd->len;
129 
130 	h->len = sizeof(struct w1_netlink_cmd) + cmd->len;
131 
132 	memcpy(c->data, cmd->data, c->len);
133 
134 	err = cn_netlink_send(cm, 0, GFP_KERNEL);
135 
136 	kfree(data);
137 
138 	return err;
139 }
140 
141 static int w1_process_command_io(struct w1_master *dev, struct cn_msg *msg,
142 		struct w1_netlink_msg *hdr, struct w1_netlink_cmd *cmd)
143 {
144 	int err = 0;
145 
146 	switch (cmd->cmd) {
147 	case W1_CMD_TOUCH:
148 		w1_touch_block(dev, cmd->data, cmd->len);
149 		w1_send_read_reply(msg, hdr, cmd);
150 		break;
151 	case W1_CMD_READ:
152 		w1_read_block(dev, cmd->data, cmd->len);
153 		w1_send_read_reply(msg, hdr, cmd);
154 		break;
155 	case W1_CMD_WRITE:
156 		w1_write_block(dev, cmd->data, cmd->len);
157 		break;
158 	default:
159 		err = -EINVAL;
160 		break;
161 	}
162 
163 	return err;
164 }
165 
166 static int w1_process_command_master(struct w1_master *dev, struct cn_msg *req_msg,
167 		struct w1_netlink_msg *req_hdr, struct w1_netlink_cmd *req_cmd)
168 {
169 	int err = -EINVAL;
170 	struct cn_msg *msg;
171 	struct w1_netlink_msg *hdr;
172 	struct w1_netlink_cmd *cmd;
173 
174 	msg = kzalloc(PAGE_SIZE, GFP_KERNEL);
175 	if (!msg)
176 		return -ENOMEM;
177 
178 	msg->id = req_msg->id;
179 	msg->seq = req_msg->seq;
180 	msg->ack = 0;
181 	msg->len = sizeof(struct w1_netlink_msg) + sizeof(struct w1_netlink_cmd);
182 
183 	hdr = (struct w1_netlink_msg *)(msg + 1);
184 	cmd = (struct w1_netlink_cmd *)(hdr + 1);
185 
186 	hdr->type = W1_MASTER_CMD;
187 	hdr->id = req_hdr->id;
188 	hdr->len = sizeof(struct w1_netlink_cmd);
189 
190 	cmd->cmd = req_cmd->cmd;
191 	cmd->len = 0;
192 
193 	switch (cmd->cmd) {
194 	case W1_CMD_SEARCH:
195 	case W1_CMD_ALARM_SEARCH:
196 		err = w1_process_search_command(dev, msg,
197 				PAGE_SIZE - msg->len - sizeof(struct cn_msg));
198 		break;
199 	case W1_CMD_READ:
200 	case W1_CMD_WRITE:
201 	case W1_CMD_TOUCH:
202 		err = w1_process_command_io(dev, req_msg, req_hdr, req_cmd);
203 		break;
204 	case W1_CMD_RESET:
205 		err = w1_reset_bus(dev);
206 		break;
207 	default:
208 		err = -EINVAL;
209 		break;
210 	}
211 
212 	kfree(msg);
213 	return err;
214 }
215 
216 static int w1_process_command_slave(struct w1_slave *sl, struct cn_msg *msg,
217 		struct w1_netlink_msg *hdr, struct w1_netlink_cmd *cmd)
218 {
219 	dev_dbg(&sl->master->dev, "%s: %02x.%012llx.%02x: cmd=%02x, len=%u.\n",
220 		__func__, sl->reg_num.family, (unsigned long long)sl->reg_num.id,
221 		sl->reg_num.crc, cmd->cmd, cmd->len);
222 
223 	return w1_process_command_io(sl->master, msg, hdr, cmd);
224 }
225 
226 static int w1_process_command_root(struct cn_msg *msg, struct w1_netlink_msg *mcmd)
227 {
228 	struct w1_master *m;
229 	struct cn_msg *cn;
230 	struct w1_netlink_msg *w;
231 	u32 *id;
232 
233 	if (mcmd->type != W1_LIST_MASTERS) {
234 		printk(KERN_NOTICE "%s: msg: %x.%x, wrong type: %u, len: %u.\n",
235 			__func__, msg->id.idx, msg->id.val, mcmd->type, mcmd->len);
236 		return -EPROTO;
237 	}
238 
239 	cn = kmalloc(PAGE_SIZE, GFP_KERNEL);
240 	if (!cn)
241 		return -ENOMEM;
242 
243 	cn->id.idx = CN_W1_IDX;
244 	cn->id.val = CN_W1_VAL;
245 
246 	cn->seq = msg->seq;
247 	cn->ack = 1;
248 	cn->len = sizeof(struct w1_netlink_msg);
249 	w = (struct w1_netlink_msg *)(cn + 1);
250 
251 	w->type = W1_LIST_MASTERS;
252 	w->status = 0;
253 	w->len = 0;
254 	id = (u32 *)(w + 1);
255 
256 	mutex_lock(&w1_mlock);
257 	list_for_each_entry(m, &w1_masters, w1_master_entry) {
258 		if (cn->len + sizeof(*id) > PAGE_SIZE - sizeof(struct cn_msg)) {
259 			cn_netlink_send(cn, 0, GFP_KERNEL);
260 			cn->ack++;
261 			cn->len = sizeof(struct w1_netlink_msg);
262 			w->len = 0;
263 			id = (u32 *)(w + 1);
264 		}
265 
266 		*id = m->id;
267 		w->len += sizeof(*id);
268 		cn->len += sizeof(*id);
269 		id++;
270 	}
271 	cn->ack = 0;
272 	cn_netlink_send(cn, 0, GFP_KERNEL);
273 	mutex_unlock(&w1_mlock);
274 
275 	kfree(cn);
276 	return 0;
277 }
278 
279 static int w1_netlink_send_error(struct cn_msg *rcmsg, struct w1_netlink_msg *rmsg,
280 		struct w1_netlink_cmd *rcmd, int error)
281 {
282 	struct cn_msg *cmsg;
283 	struct w1_netlink_msg *msg;
284 	struct w1_netlink_cmd *cmd;
285 
286 	cmsg = kzalloc(sizeof(*msg) + sizeof(*cmd) + sizeof(*cmsg), GFP_KERNEL);
287 	if (!cmsg)
288 		return -ENOMEM;
289 
290 	msg = (struct w1_netlink_msg *)(cmsg + 1);
291 	cmd = (struct w1_netlink_cmd *)(msg + 1);
292 
293 	memcpy(cmsg, rcmsg, sizeof(*cmsg));
294 	cmsg->len = sizeof(*msg);
295 
296 	memcpy(msg, rmsg, sizeof(*msg));
297 	msg->len = 0;
298 	msg->status = (short)-error;
299 
300 	if (rcmd) {
301 		memcpy(cmd, rcmd, sizeof(*cmd));
302 		cmd->len = 0;
303 		msg->len += sizeof(*cmd);
304 		cmsg->len += sizeof(*cmd);
305 	}
306 
307 	error = cn_netlink_send(cmsg, 0, GFP_KERNEL);
308 	kfree(cmsg);
309 
310 	return error;
311 }
312 
313 static void w1_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
314 {
315 	struct w1_netlink_msg *m = (struct w1_netlink_msg *)(msg + 1);
316 	struct w1_netlink_cmd *cmd;
317 	struct w1_slave *sl;
318 	struct w1_master *dev;
319 	int err = 0;
320 
321 	while (msg->len && !err) {
322 		struct w1_reg_num id;
323 		u16 mlen = m->len;
324 		u8 *cmd_data = m->data;
325 
326 		dev = NULL;
327 		sl = NULL;
328 		cmd = NULL;
329 
330 		memcpy(&id, m->id.id, sizeof(id));
331 #if 0
332 		printk("%s: %02x.%012llx.%02x: type=%02x, len=%u.\n",
333 				__func__, id.family, (unsigned long long)id.id, id.crc, m->type, m->len);
334 #endif
335 		if (m->len + sizeof(struct w1_netlink_msg) > msg->len) {
336 			err = -E2BIG;
337 			break;
338 		}
339 
340 		if (m->type == W1_MASTER_CMD) {
341 			dev = w1_search_master_id(m->id.mst.id);
342 		} else if (m->type == W1_SLAVE_CMD) {
343 			sl = w1_search_slave(&id);
344 			if (sl)
345 				dev = sl->master;
346 		} else {
347 			err = w1_process_command_root(msg, m);
348 			goto out_cont;
349 		}
350 
351 		if (!dev) {
352 			err = -ENODEV;
353 			goto out_cont;
354 		}
355 
356 		err = 0;
357 		if (!mlen)
358 			goto out_cont;
359 
360 		mutex_lock(&dev->mutex);
361 
362 		if (sl && w1_reset_select_slave(sl)) {
363 			err = -ENODEV;
364 			goto out_up;
365 		}
366 
367 		while (mlen) {
368 			cmd = (struct w1_netlink_cmd *)cmd_data;
369 
370 			if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) {
371 				err = -E2BIG;
372 				break;
373 			}
374 
375 			if (sl)
376 				err = w1_process_command_slave(sl, msg, m, cmd);
377 			else
378 				err = w1_process_command_master(dev, msg, m, cmd);
379 
380 			w1_netlink_send_error(msg, m, cmd, err);
381 			err = 0;
382 
383 			cmd_data += cmd->len + sizeof(struct w1_netlink_cmd);
384 			mlen -= cmd->len + sizeof(struct w1_netlink_cmd);
385 		}
386 out_up:
387 		atomic_dec(&dev->refcnt);
388 		if (sl)
389 			atomic_dec(&sl->refcnt);
390 		mutex_unlock(&dev->mutex);
391 out_cont:
392 		if (!cmd || err)
393 			w1_netlink_send_error(msg, m, cmd, err);
394 		msg->len -= sizeof(struct w1_netlink_msg) + m->len;
395 		m = (struct w1_netlink_msg *)(((u8 *)m) + sizeof(struct w1_netlink_msg) + m->len);
396 
397 		/*
398 		 * Let's allow requests for nonexisting devices.
399 		 */
400 		if (err == -ENODEV)
401 			err = 0;
402 	}
403 }
404 
405 int w1_init_netlink(void)
406 {
407 	struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
408 
409 	return cn_add_callback(&w1_id, "w1", &w1_cn_callback);
410 }
411 
412 void w1_fini_netlink(void)
413 {
414 	struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
415 
416 	cn_del_callback(&w1_id);
417 }
418 #else
419 void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
420 {
421 }
422 
423 int w1_init_netlink(void)
424 {
425 	return 0;
426 }
427 
428 void w1_fini_netlink(void)
429 {
430 }
431 #endif
432