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Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -08001/*
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.
Inaky Perez-Gonzalez52a8d962009-05-05 21:05:16 -0700111 *
112 * Unlike other WiMAX stack calls, this call can be used way early,
113 * even before wimax_dev_add() is called, as long as the
114 * wimax_dev->net_dev pointer is set to point to a proper
115 * net_dev. This is so that drivers can use it early in case they need
116 * to send stuff around or communicate with user space.
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800117 */
118struct sk_buff *wimax_msg_alloc(struct wimax_dev *wimax_dev,
119 const char *pipe_name,
120 const void *msg, size_t size,
121 gfp_t gfp_flags)
122{
123 int result;
Inaky Perez-Gonzalez52a8d962009-05-05 21:05:16 -0700124 struct device *dev = wimax_dev_to_dev(wimax_dev);
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800125 size_t msg_size;
126 void *genl_msg;
127 struct sk_buff *skb;
128
129 msg_size = nla_total_size(size)
130 + nla_total_size(sizeof(u32))
131 + (pipe_name ? nla_total_size(strlen(pipe_name)) : 0);
132 result = -ENOMEM;
133 skb = genlmsg_new(msg_size, gfp_flags);
134 if (skb == NULL)
135 goto error_new;
136 genl_msg = genlmsg_put(skb, 0, 0, &wimax_gnl_family,
137 0, WIMAX_GNL_OP_MSG_TO_USER);
138 if (genl_msg == NULL) {
139 dev_err(dev, "no memory to create generic netlink message\n");
140 goto error_genlmsg_put;
141 }
142 result = nla_put_u32(skb, WIMAX_GNL_MSG_IFIDX,
143 wimax_dev->net_dev->ifindex);
144 if (result < 0) {
145 dev_err(dev, "no memory to add ifindex attribute\n");
146 goto error_nla_put;
147 }
148 if (pipe_name) {
149 result = nla_put_string(skb, WIMAX_GNL_MSG_PIPE_NAME,
150 pipe_name);
151 if (result < 0) {
152 dev_err(dev, "no memory to add pipe_name attribute\n");
153 goto error_nla_put;
154 }
155 }
156 result = nla_put(skb, WIMAX_GNL_MSG_DATA, size, msg);
157 if (result < 0) {
Inaky Perez-Gonzalezd1a26272009-03-30 17:50:17 -0700158 dev_err(dev, "no memory to add payload (msg %p size %zu) in "
159 "attribute: %d\n", msg, size, result);
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800160 goto error_nla_put;
161 }
162 genlmsg_end(skb, genl_msg);
163 return skb;
164
165error_nla_put:
166error_genlmsg_put:
167error_new:
168 nlmsg_free(skb);
169 return ERR_PTR(result);
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800170}
171EXPORT_SYMBOL_GPL(wimax_msg_alloc);
172
173
174/**
175 * wimax_msg_data_len - Return a pointer and size of a message's payload
176 *
177 * @msg: Pointer to a message created with wimax_msg_alloc()
178 * @size: Pointer to where to store the message's size
179 *
180 * Returns the pointer to the message data.
181 */
182const void *wimax_msg_data_len(struct sk_buff *msg, size_t *size)
183{
184 struct nlmsghdr *nlh = (void *) msg->head;
185 struct nlattr *nla;
186
187 nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr),
188 WIMAX_GNL_MSG_DATA);
189 if (nla == NULL) {
190 printk(KERN_ERR "Cannot find attribute WIMAX_GNL_MSG_DATA\n");
191 return NULL;
192 }
193 *size = nla_len(nla);
194 return nla_data(nla);
195}
196EXPORT_SYMBOL_GPL(wimax_msg_data_len);
197
198
199/**
200 * wimax_msg_data - Return a pointer to a message's payload
201 *
202 * @msg: Pointer to a message created with wimax_msg_alloc()
203 */
204const void *wimax_msg_data(struct sk_buff *msg)
205{
206 struct nlmsghdr *nlh = (void *) msg->head;
207 struct nlattr *nla;
208
209 nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr),
210 WIMAX_GNL_MSG_DATA);
211 if (nla == NULL) {
212 printk(KERN_ERR "Cannot find attribute WIMAX_GNL_MSG_DATA\n");
213 return NULL;
214 }
215 return nla_data(nla);
216}
217EXPORT_SYMBOL_GPL(wimax_msg_data);
218
219
220/**
221 * wimax_msg_len - Return a message's payload length
222 *
223 * @msg: Pointer to a message created with wimax_msg_alloc()
224 */
225ssize_t wimax_msg_len(struct sk_buff *msg)
226{
227 struct nlmsghdr *nlh = (void *) msg->head;
228 struct nlattr *nla;
229
230 nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr),
231 WIMAX_GNL_MSG_DATA);
232 if (nla == NULL) {
233 printk(KERN_ERR "Cannot find attribute WIMAX_GNL_MSG_DATA\n");
234 return -EINVAL;
235 }
236 return nla_len(nla);
237}
238EXPORT_SYMBOL_GPL(wimax_msg_len);
239
240
241/**
242 * wimax_msg_send - Send a pre-allocated message to user space
243 *
244 * @wimax_dev: WiMAX device descriptor
245 *
246 * @skb: &struct sk_buff returned by wimax_msg_alloc(). Note the
247 * ownership of @skb is transferred to this function.
248 *
249 * Returns: 0 if ok, < 0 errno code on error
250 *
251 * Description:
252 *
253 * Sends a free-form message that was preallocated with
254 * wimax_msg_alloc() and filled up.
255 *
256 * Assumes that once you pass an skb to this function for sending, it
257 * owns it and will release it when done (on success).
258 *
259 * IMPORTANT:
260 *
261 * Don't use skb_push()/skb_pull()/skb_reserve() on the skb, as
262 * wimax_msg_send() depends on skb->data being placed at the
263 * beginning of the user message.
Inaky Perez-Gonzalez52a8d962009-05-05 21:05:16 -0700264 *
265 * Unlike other WiMAX stack calls, this call can be used way early,
266 * even before wimax_dev_add() is called, as long as the
267 * wimax_dev->net_dev pointer is set to point to a proper
268 * net_dev. This is so that drivers can use it early in case they need
269 * to send stuff around or communicate with user space.
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800270 */
271int wimax_msg_send(struct wimax_dev *wimax_dev, struct sk_buff *skb)
272{
Inaky Perez-Gonzalez52a8d962009-05-05 21:05:16 -0700273 struct device *dev = wimax_dev_to_dev(wimax_dev);
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800274 void *msg = skb->data;
275 size_t size = skb->len;
276 might_sleep();
277
278 d_printf(1, dev, "CTX: wimax msg, %zu bytes\n", size);
279 d_dump(2, dev, msg, size);
Pablo Neira Ayusoff491a72009-02-05 23:56:36 -0800280 genlmsg_multicast(skb, 0, wimax_gnl_mcg.id, GFP_KERNEL);
281 d_printf(1, dev, "CTX: genl multicast done\n");
282 return 0;
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800283}
284EXPORT_SYMBOL_GPL(wimax_msg_send);
285
286
287/**
288 * wimax_msg - Send a message to user space
289 *
290 * @wimax_dev: WiMAX device descriptor (properly referenced)
291 * @pipe_name: "named pipe" the message will be sent to
292 * @buf: pointer to the message to send.
293 * @size: size of the buffer pointed to by @buf (in bytes).
294 * @gfp_flags: flags for memory allocation.
295 *
296 * Returns: %0 if ok, negative errno code on error.
297 *
298 * Description:
299 *
300 * Sends a free-form message to user space on the device @wimax_dev.
301 *
302 * NOTES:
303 *
304 * Once the @skb is given to this function, who will own it and will
305 * release it when done (unless it returns error).
306 */
307int wimax_msg(struct wimax_dev *wimax_dev, const char *pipe_name,
308 const void *buf, size_t size, gfp_t gfp_flags)
309{
310 int result = -ENOMEM;
311 struct sk_buff *skb;
312
313 skb = wimax_msg_alloc(wimax_dev, pipe_name, buf, size, gfp_flags);
Inaky Perez-Gonzalezd1a26272009-03-30 17:50:17 -0700314 if (IS_ERR(skb))
315 result = PTR_ERR(skb);
316 else
317 result = wimax_msg_send(wimax_dev, skb);
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800318 return result;
319}
320EXPORT_SYMBOL_GPL(wimax_msg);
321
322
323static const
324struct nla_policy wimax_gnl_msg_policy[WIMAX_GNL_ATTR_MAX + 1] = {
325 [WIMAX_GNL_MSG_IFIDX] = {
326 .type = NLA_U32,
327 },
328 [WIMAX_GNL_MSG_DATA] = {
329 .type = NLA_UNSPEC, /* libnl doesn't grok BINARY yet */
330 },
331};
332
333
334/*
335 * Relays a message from user space to the driver
336 *
337 * The skb is passed to the driver-specific function with the netlink
338 * and generic netlink headers already stripped.
339 *
340 * This call will block while handling/relaying the message.
341 */
342static
343int wimax_gnl_doit_msg_from_user(struct sk_buff *skb, struct genl_info *info)
344{
345 int result, ifindex;
346 struct wimax_dev *wimax_dev;
347 struct device *dev;
348 struct nlmsghdr *nlh = info->nlhdr;
349 char *pipe_name;
350 void *msg_buf;
351 size_t msg_len;
352
353 might_sleep();
354 d_fnstart(3, NULL, "(skb %p info %p)\n", skb, info);
355 result = -ENODEV;
356 if (info->attrs[WIMAX_GNL_MSG_IFIDX] == NULL) {
357 printk(KERN_ERR "WIMAX_GNL_MSG_FROM_USER: can't find IFIDX "
358 "attribute\n");
359 goto error_no_wimax_dev;
360 }
361 ifindex = nla_get_u32(info->attrs[WIMAX_GNL_MSG_IFIDX]);
362 wimax_dev = wimax_dev_get_by_genl_info(info, ifindex);
363 if (wimax_dev == NULL)
364 goto error_no_wimax_dev;
365 dev = wimax_dev_to_dev(wimax_dev);
366
367 /* Unpack arguments */
368 result = -EINVAL;
369 if (info->attrs[WIMAX_GNL_MSG_DATA] == NULL) {
370 dev_err(dev, "WIMAX_GNL_MSG_FROM_USER: can't find MSG_DATA "
371 "attribute\n");
372 goto error_no_data;
373 }
374 msg_buf = nla_data(info->attrs[WIMAX_GNL_MSG_DATA]);
375 msg_len = nla_len(info->attrs[WIMAX_GNL_MSG_DATA]);
376
377 if (info->attrs[WIMAX_GNL_MSG_PIPE_NAME] == NULL)
378 pipe_name = NULL;
379 else {
380 struct nlattr *attr = info->attrs[WIMAX_GNL_MSG_PIPE_NAME];
381 size_t attr_len = nla_len(attr);
382 /* libnl-1.1 does not yet support NLA_NUL_STRING */
383 result = -ENOMEM;
384 pipe_name = kstrndup(nla_data(attr), attr_len + 1, GFP_KERNEL);
385 if (pipe_name == NULL)
386 goto error_alloc;
387 pipe_name[attr_len] = 0;
388 }
389 mutex_lock(&wimax_dev->mutex);
390 result = wimax_dev_is_ready(wimax_dev);
391 if (result < 0)
392 goto error_not_ready;
393 result = -ENOSYS;
394 if (wimax_dev->op_msg_from_user == NULL)
395 goto error_noop;
396
397 d_printf(1, dev,
398 "CRX: nlmsghdr len %u type %u flags 0x%04x seq 0x%x pid %u\n",
399 nlh->nlmsg_len, nlh->nlmsg_type, nlh->nlmsg_flags,
400 nlh->nlmsg_seq, nlh->nlmsg_pid);
401 d_printf(1, dev, "CRX: wimax message %zu bytes\n", msg_len);
402 d_dump(2, dev, msg_buf, msg_len);
403
404 result = wimax_dev->op_msg_from_user(wimax_dev, pipe_name,
405 msg_buf, msg_len, info);
406error_noop:
407error_not_ready:
408 mutex_unlock(&wimax_dev->mutex);
409error_alloc:
410 kfree(pipe_name);
411error_no_data:
412 dev_put(wimax_dev->net_dev);
413error_no_wimax_dev:
414 d_fnend(3, NULL, "(skb %p info %p) = %d\n", skb, info, result);
415 return result;
416}
417
418
419/*
420 * Generic Netlink glue
421 */
422
423struct genl_ops wimax_gnl_msg_from_user = {
424 .cmd = WIMAX_GNL_OP_MSG_FROM_USER,
425 .flags = GENL_ADMIN_PERM,
426 .policy = wimax_gnl_msg_policy,
427 .doit = wimax_gnl_doit_msg_from_user,
428 .dumpit = NULL,
429};
430