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 */
wimax_msg_alloc(struct wimax_dev * wimax_dev,const char * pipe_name,const void * msg,size_t size,gfp_t gfp_flags)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 */
wimax_msg_data_len(struct sk_buff * msg,size_t * size)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 */
wimax_msg_data(struct sk_buff * msg)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 */
wimax_msg_len(struct sk_buff * msg)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 */
wimax_msg_send(struct wimax_dev * wimax_dev,struct sk_buff * skb)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 */
wimax_msg(struct wimax_dev * wimax_dev,const char * pipe_name,const void * buf,size_t size,gfp_t gfp_flags)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
wimax_gnl_doit_msg_from_user(struct sk_buff * skb,struct genl_info * info)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
422