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3e65646b IPG |
1 | /* |
2 | * Linux WiMAX | |
3 | * Generic messaging interface between userspace and driver/device | |
4 | * | |
5 | * | |
6 | * Copyright (C) 2007-2008 Intel Corporation <linux-wimax@intel.com> | |
7 | * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License version | |
11 | * 2 as published by the Free Software Foundation. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA | |
21 | * 02110-1301, USA. | |
22 | * | |
23 | * | |
24 | * This implements a direct communication channel between user space and | |
25 | * the driver/device, by which free form messages can be sent back and | |
26 | * forth. | |
27 | * | |
28 | * This is intended for device-specific features, vendor quirks, etc. | |
29 | * | |
30 | * See include/net/wimax.h | |
31 | * | |
32 | * GENERIC NETLINK ENCODING AND CAPACITY | |
33 | * | |
34 | * A destination "pipe name" is added to each message; it is up to the | |
35 | * drivers to assign or use those names (if using them at all). | |
36 | * | |
37 | * Messages are encoded as a binary netlink attribute using nla_put() | |
38 | * using type NLA_UNSPEC (as some versions of libnl still in | |
39 | * deployment don't yet understand NLA_BINARY). | |
40 | * | |
41 | * The maximum capacity of this transport is PAGESIZE per message (so | |
42 | * the actual payload will be bit smaller depending on the | |
43 | * netlink/generic netlink attributes and headers). | |
44 | * | |
45 | * RECEPTION OF MESSAGES | |
46 | * | |
47 | * When a message is received from user space, it is passed verbatim | |
48 | * to the driver calling wimax_dev->op_msg_from_user(). The return | |
49 | * value from this function is passed back to user space as an ack | |
50 | * over the generic netlink protocol. | |
51 | * | |
52 | * The stack doesn't do any processing or interpretation of these | |
53 | * messages. | |
54 | * | |
55 | * SENDING MESSAGES | |
56 | * | |
57 | * Messages can be sent with wimax_msg(). | |
58 | * | |
59 | * If the message delivery needs to happen on a different context to | |
60 | * that of its creation, wimax_msg_alloc() can be used to get a | |
61 | * pointer to the message that can be delivered later on with | |
62 | * wimax_msg_send(). | |
63 | * | |
64 | * ROADMAP | |
65 | * | |
66 | * wimax_gnl_doit_msg_from_user() Process a message from user space | |
67 | * wimax_dev_get_by_genl_info() | |
68 | * wimax_dev->op_msg_from_user() Delivery of message to the driver | |
69 | * | |
70 | * wimax_msg() Send a message to user space | |
71 | * wimax_msg_alloc() | |
72 | * wimax_msg_send() | |
73 | */ | |
74 | #include <linux/device.h> | |
75 | #include <net/genetlink.h> | |
76 | #include <linux/netdevice.h> | |
77 | #include <linux/wimax.h> | |
78 | #include <linux/security.h> | |
79 | #include "wimax-internal.h" | |
80 | ||
81 | ||
82 | #define D_SUBMODULE op_msg | |
83 | #include "debug-levels.h" | |
84 | ||
85 | ||
86 | /** | |
87 | * wimax_msg_alloc - Create a new skb for sending a message to userspace | |
88 | * | |
89 | * @wimax_dev: WiMAX device descriptor | |
90 | * @pipe_name: "named pipe" the message will be sent to | |
91 | * @msg: pointer to the message data to send | |
92 | * @size: size of the message to send (in bytes), including the header. | |
93 | * @gfp_flags: flags for memory allocation. | |
94 | * | |
95 | * Returns: %0 if ok, negative errno code on error | |
96 | * | |
97 | * Description: | |
98 | * | |
99 | * Allocates an skb that will contain the message to send to user | |
100 | * space over the messaging pipe and initializes it, copying the | |
101 | * payload. | |
102 | * | |
103 | * Once this call is done, you can deliver it with | |
104 | * wimax_msg_send(). | |
105 | * | |
106 | * IMPORTANT: | |
107 | * | |
108 | * Don't use skb_push()/skb_pull()/skb_reserve() on the skb, as | |
109 | * wimax_msg_send() depends on skb->data being placed at the | |
110 | * beginning of the user message. | |
111 | */ | |
112 | struct sk_buff *wimax_msg_alloc(struct wimax_dev *wimax_dev, | |
113 | const char *pipe_name, | |
114 | const void *msg, size_t size, | |
115 | gfp_t gfp_flags) | |
116 | { | |
117 | int result; | |
118 | struct device *dev = wimax_dev->net_dev->dev.parent; | |
119 | size_t msg_size; | |
120 | void *genl_msg; | |
121 | struct sk_buff *skb; | |
122 | ||
123 | msg_size = nla_total_size(size) | |
124 | + nla_total_size(sizeof(u32)) | |
125 | + (pipe_name ? nla_total_size(strlen(pipe_name)) : 0); | |
126 | result = -ENOMEM; | |
127 | skb = genlmsg_new(msg_size, gfp_flags); | |
128 | if (skb == NULL) | |
129 | goto error_new; | |
130 | genl_msg = genlmsg_put(skb, 0, 0, &wimax_gnl_family, | |
131 | 0, WIMAX_GNL_OP_MSG_TO_USER); | |
132 | if (genl_msg == NULL) { | |
133 | dev_err(dev, "no memory to create generic netlink message\n"); | |
134 | goto error_genlmsg_put; | |
135 | } | |
136 | result = nla_put_u32(skb, WIMAX_GNL_MSG_IFIDX, | |
137 | wimax_dev->net_dev->ifindex); | |
138 | if (result < 0) { | |
139 | dev_err(dev, "no memory to add ifindex attribute\n"); | |
140 | goto error_nla_put; | |
141 | } | |
142 | if (pipe_name) { | |
143 | result = nla_put_string(skb, WIMAX_GNL_MSG_PIPE_NAME, | |
144 | pipe_name); | |
145 | if (result < 0) { | |
146 | dev_err(dev, "no memory to add pipe_name attribute\n"); | |
147 | goto error_nla_put; | |
148 | } | |
149 | } | |
150 | result = nla_put(skb, WIMAX_GNL_MSG_DATA, size, msg); | |
151 | if (result < 0) { | |
152 | dev_err(dev, "no memory to add payload in attribute\n"); | |
153 | goto error_nla_put; | |
154 | } | |
155 | genlmsg_end(skb, genl_msg); | |
156 | return skb; | |
157 | ||
158 | error_nla_put: | |
159 | error_genlmsg_put: | |
160 | error_new: | |
161 | nlmsg_free(skb); | |
162 | return ERR_PTR(result); | |
163 | ||
164 | } | |
165 | EXPORT_SYMBOL_GPL(wimax_msg_alloc); | |
166 | ||
167 | ||
168 | /** | |
169 | * wimax_msg_data_len - Return a pointer and size of a message's payload | |
170 | * | |
171 | * @msg: Pointer to a message created with wimax_msg_alloc() | |
172 | * @size: Pointer to where to store the message's size | |
173 | * | |
174 | * Returns the pointer to the message data. | |
175 | */ | |
176 | const void *wimax_msg_data_len(struct sk_buff *msg, size_t *size) | |
177 | { | |
178 | struct nlmsghdr *nlh = (void *) msg->head; | |
179 | struct nlattr *nla; | |
180 | ||
181 | nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr), | |
182 | WIMAX_GNL_MSG_DATA); | |
183 | if (nla == NULL) { | |
184 | printk(KERN_ERR "Cannot find attribute WIMAX_GNL_MSG_DATA\n"); | |
185 | return NULL; | |
186 | } | |
187 | *size = nla_len(nla); | |
188 | return nla_data(nla); | |
189 | } | |
190 | EXPORT_SYMBOL_GPL(wimax_msg_data_len); | |
191 | ||
192 | ||
193 | /** | |
194 | * wimax_msg_data - Return a pointer to a message's payload | |
195 | * | |
196 | * @msg: Pointer to a message created with wimax_msg_alloc() | |
197 | */ | |
198 | const void *wimax_msg_data(struct sk_buff *msg) | |
199 | { | |
200 | struct nlmsghdr *nlh = (void *) msg->head; | |
201 | struct nlattr *nla; | |
202 | ||
203 | nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr), | |
204 | WIMAX_GNL_MSG_DATA); | |
205 | if (nla == NULL) { | |
206 | printk(KERN_ERR "Cannot find attribute WIMAX_GNL_MSG_DATA\n"); | |
207 | return NULL; | |
208 | } | |
209 | return nla_data(nla); | |
210 | } | |
211 | EXPORT_SYMBOL_GPL(wimax_msg_data); | |
212 | ||
213 | ||
214 | /** | |
215 | * wimax_msg_len - Return a message's payload length | |
216 | * | |
217 | * @msg: Pointer to a message created with wimax_msg_alloc() | |
218 | */ | |
219 | ssize_t wimax_msg_len(struct sk_buff *msg) | |
220 | { | |
221 | struct nlmsghdr *nlh = (void *) msg->head; | |
222 | struct nlattr *nla; | |
223 | ||
224 | nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr), | |
225 | WIMAX_GNL_MSG_DATA); | |
226 | if (nla == NULL) { | |
227 | printk(KERN_ERR "Cannot find attribute WIMAX_GNL_MSG_DATA\n"); | |
228 | return -EINVAL; | |
229 | } | |
230 | return nla_len(nla); | |
231 | } | |
232 | EXPORT_SYMBOL_GPL(wimax_msg_len); | |
233 | ||
234 | ||
235 | /** | |
236 | * wimax_msg_send - Send a pre-allocated message to user space | |
237 | * | |
238 | * @wimax_dev: WiMAX device descriptor | |
239 | * | |
240 | * @skb: &struct sk_buff returned by wimax_msg_alloc(). Note the | |
241 | * ownership of @skb is transferred to this function. | |
242 | * | |
243 | * Returns: 0 if ok, < 0 errno code on error | |
244 | * | |
245 | * Description: | |
246 | * | |
247 | * Sends a free-form message that was preallocated with | |
248 | * wimax_msg_alloc() and filled up. | |
249 | * | |
250 | * Assumes that once you pass an skb to this function for sending, it | |
251 | * owns it and will release it when done (on success). | |
252 | * | |
253 | * IMPORTANT: | |
254 | * | |
255 | * Don't use skb_push()/skb_pull()/skb_reserve() on the skb, as | |
256 | * wimax_msg_send() depends on skb->data being placed at the | |
257 | * beginning of the user message. | |
258 | */ | |
259 | int wimax_msg_send(struct wimax_dev *wimax_dev, struct sk_buff *skb) | |
260 | { | |
261 | int result; | |
262 | struct device *dev = wimax_dev->net_dev->dev.parent; | |
263 | void *msg = skb->data; | |
264 | size_t size = skb->len; | |
265 | might_sleep(); | |
266 | ||
267 | d_printf(1, dev, "CTX: wimax msg, %zu bytes\n", size); | |
268 | d_dump(2, dev, msg, size); | |
269 | result = genlmsg_multicast(skb, 0, wimax_gnl_mcg.id, GFP_KERNEL); | |
270 | d_printf(1, dev, "CTX: genl multicast result %d\n", result); | |
271 | if (result == -ESRCH) /* Nobody connected, ignore it */ | |
272 | result = 0; /* btw, the skb is freed already */ | |
273 | return result; | |
274 | } | |
275 | EXPORT_SYMBOL_GPL(wimax_msg_send); | |
276 | ||
277 | ||
278 | /** | |
279 | * wimax_msg - Send a message to user space | |
280 | * | |
281 | * @wimax_dev: WiMAX device descriptor (properly referenced) | |
282 | * @pipe_name: "named pipe" the message will be sent to | |
283 | * @buf: pointer to the message to send. | |
284 | * @size: size of the buffer pointed to by @buf (in bytes). | |
285 | * @gfp_flags: flags for memory allocation. | |
286 | * | |
287 | * Returns: %0 if ok, negative errno code on error. | |
288 | * | |
289 | * Description: | |
290 | * | |
291 | * Sends a free-form message to user space on the device @wimax_dev. | |
292 | * | |
293 | * NOTES: | |
294 | * | |
295 | * Once the @skb is given to this function, who will own it and will | |
296 | * release it when done (unless it returns error). | |
297 | */ | |
298 | int wimax_msg(struct wimax_dev *wimax_dev, const char *pipe_name, | |
299 | const void *buf, size_t size, gfp_t gfp_flags) | |
300 | { | |
301 | int result = -ENOMEM; | |
302 | struct sk_buff *skb; | |
303 | ||
304 | skb = wimax_msg_alloc(wimax_dev, pipe_name, buf, size, gfp_flags); | |
305 | if (skb == NULL) | |
306 | goto error_msg_new; | |
307 | result = wimax_msg_send(wimax_dev, skb); | |
308 | error_msg_new: | |
309 | return result; | |
310 | } | |
311 | EXPORT_SYMBOL_GPL(wimax_msg); | |
312 | ||
313 | ||
314 | static const | |
315 | struct nla_policy wimax_gnl_msg_policy[WIMAX_GNL_ATTR_MAX + 1] = { | |
316 | [WIMAX_GNL_MSG_IFIDX] = { | |
317 | .type = NLA_U32, | |
318 | }, | |
319 | [WIMAX_GNL_MSG_DATA] = { | |
320 | .type = NLA_UNSPEC, /* libnl doesn't grok BINARY yet */ | |
321 | }, | |
322 | }; | |
323 | ||
324 | ||
325 | /* | |
326 | * Relays a message from user space to the driver | |
327 | * | |
328 | * The skb is passed to the driver-specific function with the netlink | |
329 | * and generic netlink headers already stripped. | |
330 | * | |
331 | * This call will block while handling/relaying the message. | |
332 | */ | |
333 | static | |
334 | int wimax_gnl_doit_msg_from_user(struct sk_buff *skb, struct genl_info *info) | |
335 | { | |
336 | int result, ifindex; | |
337 | struct wimax_dev *wimax_dev; | |
338 | struct device *dev; | |
339 | struct nlmsghdr *nlh = info->nlhdr; | |
340 | char *pipe_name; | |
341 | void *msg_buf; | |
342 | size_t msg_len; | |
343 | ||
344 | might_sleep(); | |
345 | d_fnstart(3, NULL, "(skb %p info %p)\n", skb, info); | |
346 | result = -ENODEV; | |
347 | if (info->attrs[WIMAX_GNL_MSG_IFIDX] == NULL) { | |
348 | printk(KERN_ERR "WIMAX_GNL_MSG_FROM_USER: can't find IFIDX " | |
349 | "attribute\n"); | |
350 | goto error_no_wimax_dev; | |
351 | } | |
352 | ifindex = nla_get_u32(info->attrs[WIMAX_GNL_MSG_IFIDX]); | |
353 | wimax_dev = wimax_dev_get_by_genl_info(info, ifindex); | |
354 | if (wimax_dev == NULL) | |
355 | goto error_no_wimax_dev; | |
356 | dev = wimax_dev_to_dev(wimax_dev); | |
357 | ||
358 | /* Unpack arguments */ | |
359 | result = -EINVAL; | |
360 | if (info->attrs[WIMAX_GNL_MSG_DATA] == NULL) { | |
361 | dev_err(dev, "WIMAX_GNL_MSG_FROM_USER: can't find MSG_DATA " | |
362 | "attribute\n"); | |
363 | goto error_no_data; | |
364 | } | |
365 | msg_buf = nla_data(info->attrs[WIMAX_GNL_MSG_DATA]); | |
366 | msg_len = nla_len(info->attrs[WIMAX_GNL_MSG_DATA]); | |
367 | ||
368 | if (info->attrs[WIMAX_GNL_MSG_PIPE_NAME] == NULL) | |
369 | pipe_name = NULL; | |
370 | else { | |
371 | struct nlattr *attr = info->attrs[WIMAX_GNL_MSG_PIPE_NAME]; | |
372 | size_t attr_len = nla_len(attr); | |
373 | /* libnl-1.1 does not yet support NLA_NUL_STRING */ | |
374 | result = -ENOMEM; | |
375 | pipe_name = kstrndup(nla_data(attr), attr_len + 1, GFP_KERNEL); | |
376 | if (pipe_name == NULL) | |
377 | goto error_alloc; | |
378 | pipe_name[attr_len] = 0; | |
379 | } | |
380 | mutex_lock(&wimax_dev->mutex); | |
381 | result = wimax_dev_is_ready(wimax_dev); | |
382 | if (result < 0) | |
383 | goto error_not_ready; | |
384 | result = -ENOSYS; | |
385 | if (wimax_dev->op_msg_from_user == NULL) | |
386 | goto error_noop; | |
387 | ||
388 | d_printf(1, dev, | |
389 | "CRX: nlmsghdr len %u type %u flags 0x%04x seq 0x%x pid %u\n", | |
390 | nlh->nlmsg_len, nlh->nlmsg_type, nlh->nlmsg_flags, | |
391 | nlh->nlmsg_seq, nlh->nlmsg_pid); | |
392 | d_printf(1, dev, "CRX: wimax message %zu bytes\n", msg_len); | |
393 | d_dump(2, dev, msg_buf, msg_len); | |
394 | ||
395 | result = wimax_dev->op_msg_from_user(wimax_dev, pipe_name, | |
396 | msg_buf, msg_len, info); | |
397 | error_noop: | |
398 | error_not_ready: | |
399 | mutex_unlock(&wimax_dev->mutex); | |
400 | error_alloc: | |
401 | kfree(pipe_name); | |
402 | error_no_data: | |
403 | dev_put(wimax_dev->net_dev); | |
404 | error_no_wimax_dev: | |
405 | d_fnend(3, NULL, "(skb %p info %p) = %d\n", skb, info, result); | |
406 | return result; | |
407 | } | |
408 | ||
409 | ||
410 | /* | |
411 | * Generic Netlink glue | |
412 | */ | |
413 | ||
414 | struct genl_ops wimax_gnl_msg_from_user = { | |
415 | .cmd = WIMAX_GNL_OP_MSG_FROM_USER, | |
416 | .flags = GENL_ADMIN_PERM, | |
417 | .policy = wimax_gnl_msg_policy, | |
418 | .doit = wimax_gnl_doit_msg_from_user, | |
419 | .dumpit = NULL, | |
420 | }; | |
421 |