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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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090075#include <linux/slab.h>
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -080076#include <net/genetlink.h>
77#include <linux/netdevice.h>
78#include <linux/wimax.h>
79#include <linux/security.h>
80#include "wimax-internal.h"
81
82
83#define D_SUBMODULE op_msg
84#include "debug-levels.h"
85
86
87/**
88 * wimax_msg_alloc - Create a new skb for sending a message to userspace
89 *
90 * @wimax_dev: WiMAX device descriptor
91 * @pipe_name: "named pipe" the message will be sent to
92 * @msg: pointer to the message data to send
93 * @size: size of the message to send (in bytes), including the header.
94 * @gfp_flags: flags for memory allocation.
95 *
96 * Returns: %0 if ok, negative errno code on error
97 *
98 * Description:
99 *
100 * Allocates an skb that will contain the message to send to user
101 * space over the messaging pipe and initializes it, copying the
102 * payload.
103 *
104 * Once this call is done, you can deliver it with
105 * wimax_msg_send().
106 *
107 * IMPORTANT:
108 *
109 * Don't use skb_push()/skb_pull()/skb_reserve() on the skb, as
110 * wimax_msg_send() depends on skb->data being placed at the
111 * beginning of the user message.
Inaky Perez-Gonzalez52a8d962009-05-05 21:05:16 -0700112 *
113 * Unlike other WiMAX stack calls, this call can be used way early,
114 * even before wimax_dev_add() is called, as long as the
115 * wimax_dev->net_dev pointer is set to point to a proper
116 * net_dev. This is so that drivers can use it early in case they need
117 * to send stuff around or communicate with user space.
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800118 */
119struct sk_buff *wimax_msg_alloc(struct wimax_dev *wimax_dev,
120 const char *pipe_name,
121 const void *msg, size_t size,
122 gfp_t gfp_flags)
123{
124 int result;
Inaky Perez-Gonzalez52a8d962009-05-05 21:05:16 -0700125 struct device *dev = wimax_dev_to_dev(wimax_dev);
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800126 size_t msg_size;
127 void *genl_msg;
128 struct sk_buff *skb;
129
130 msg_size = nla_total_size(size)
131 + nla_total_size(sizeof(u32))
132 + (pipe_name ? nla_total_size(strlen(pipe_name)) : 0);
133 result = -ENOMEM;
134 skb = genlmsg_new(msg_size, gfp_flags);
135 if (skb == NULL)
136 goto error_new;
137 genl_msg = genlmsg_put(skb, 0, 0, &wimax_gnl_family,
138 0, WIMAX_GNL_OP_MSG_TO_USER);
139 if (genl_msg == NULL) {
140 dev_err(dev, "no memory to create generic netlink message\n");
141 goto error_genlmsg_put;
142 }
143 result = nla_put_u32(skb, WIMAX_GNL_MSG_IFIDX,
144 wimax_dev->net_dev->ifindex);
145 if (result < 0) {
146 dev_err(dev, "no memory to add ifindex attribute\n");
147 goto error_nla_put;
148 }
149 if (pipe_name) {
150 result = nla_put_string(skb, WIMAX_GNL_MSG_PIPE_NAME,
151 pipe_name);
152 if (result < 0) {
153 dev_err(dev, "no memory to add pipe_name attribute\n");
154 goto error_nla_put;
155 }
156 }
157 result = nla_put(skb, WIMAX_GNL_MSG_DATA, size, msg);
158 if (result < 0) {
Inaky Perez-Gonzalezd1a26272009-03-30 17:50:17 -0700159 dev_err(dev, "no memory to add payload (msg %p size %zu) in "
160 "attribute: %d\n", msg, size, result);
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800161 goto error_nla_put;
162 }
163 genlmsg_end(skb, genl_msg);
164 return skb;
165
166error_nla_put:
167error_genlmsg_put:
168error_new:
169 nlmsg_free(skb);
170 return ERR_PTR(result);
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800171}
172EXPORT_SYMBOL_GPL(wimax_msg_alloc);
173
174
175/**
176 * wimax_msg_data_len - Return a pointer and size of a message's payload
177 *
178 * @msg: Pointer to a message created with wimax_msg_alloc()
179 * @size: Pointer to where to store the message's size
180 *
181 * Returns the pointer to the message data.
182 */
183const void *wimax_msg_data_len(struct sk_buff *msg, size_t *size)
184{
185 struct nlmsghdr *nlh = (void *) msg->head;
186 struct nlattr *nla;
187
188 nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr),
189 WIMAX_GNL_MSG_DATA);
190 if (nla == NULL) {
191 printk(KERN_ERR "Cannot find attribute WIMAX_GNL_MSG_DATA\n");
192 return NULL;
193 }
194 *size = nla_len(nla);
195 return nla_data(nla);
196}
197EXPORT_SYMBOL_GPL(wimax_msg_data_len);
198
199
200/**
201 * wimax_msg_data - Return a pointer to a message's payload
202 *
203 * @msg: Pointer to a message created with wimax_msg_alloc()
204 */
205const void *wimax_msg_data(struct sk_buff *msg)
206{
207 struct nlmsghdr *nlh = (void *) msg->head;
208 struct nlattr *nla;
209
210 nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr),
211 WIMAX_GNL_MSG_DATA);
212 if (nla == NULL) {
213 printk(KERN_ERR "Cannot find attribute WIMAX_GNL_MSG_DATA\n");
214 return NULL;
215 }
216 return nla_data(nla);
217}
218EXPORT_SYMBOL_GPL(wimax_msg_data);
219
220
221/**
222 * wimax_msg_len - Return a message's payload length
223 *
224 * @msg: Pointer to a message created with wimax_msg_alloc()
225 */
226ssize_t wimax_msg_len(struct sk_buff *msg)
227{
228 struct nlmsghdr *nlh = (void *) msg->head;
229 struct nlattr *nla;
230
231 nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr),
232 WIMAX_GNL_MSG_DATA);
233 if (nla == NULL) {
234 printk(KERN_ERR "Cannot find attribute WIMAX_GNL_MSG_DATA\n");
235 return -EINVAL;
236 }
237 return nla_len(nla);
238}
239EXPORT_SYMBOL_GPL(wimax_msg_len);
240
241
242/**
243 * wimax_msg_send - Send a pre-allocated message to user space
244 *
245 * @wimax_dev: WiMAX device descriptor
246 *
247 * @skb: &struct sk_buff returned by wimax_msg_alloc(). Note the
248 * ownership of @skb is transferred to this function.
249 *
250 * Returns: 0 if ok, < 0 errno code on error
251 *
252 * Description:
253 *
254 * Sends a free-form message that was preallocated with
255 * wimax_msg_alloc() and filled up.
256 *
257 * Assumes that once you pass an skb to this function for sending, it
258 * owns it and will release it when done (on success).
259 *
260 * IMPORTANT:
261 *
262 * Don't use skb_push()/skb_pull()/skb_reserve() on the skb, as
263 * wimax_msg_send() depends on skb->data being placed at the
264 * beginning of the user message.
Inaky Perez-Gonzalez52a8d962009-05-05 21:05:16 -0700265 *
266 * Unlike other WiMAX stack calls, this call can be used way early,
267 * even before wimax_dev_add() is called, as long as the
268 * wimax_dev->net_dev pointer is set to point to a proper
269 * net_dev. This is so that drivers can use it early in case they need
270 * to send stuff around or communicate with user space.
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800271 */
272int wimax_msg_send(struct wimax_dev *wimax_dev, struct sk_buff *skb)
273{
Inaky Perez-Gonzalez52a8d962009-05-05 21:05:16 -0700274 struct device *dev = wimax_dev_to_dev(wimax_dev);
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800275 void *msg = skb->data;
276 size_t size = skb->len;
277 might_sleep();
278
279 d_printf(1, dev, "CTX: wimax msg, %zu bytes\n", size);
280 d_dump(2, dev, msg, size);
Pablo Neira Ayusoff491a72009-02-05 23:56:36 -0800281 genlmsg_multicast(skb, 0, wimax_gnl_mcg.id, GFP_KERNEL);
282 d_printf(1, dev, "CTX: genl multicast done\n");
283 return 0;
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800284}
285EXPORT_SYMBOL_GPL(wimax_msg_send);
286
287
288/**
289 * wimax_msg - Send a message to user space
290 *
291 * @wimax_dev: WiMAX device descriptor (properly referenced)
292 * @pipe_name: "named pipe" the message will be sent to
293 * @buf: pointer to the message to send.
294 * @size: size of the buffer pointed to by @buf (in bytes).
295 * @gfp_flags: flags for memory allocation.
296 *
297 * Returns: %0 if ok, negative errno code on error.
298 *
299 * Description:
300 *
301 * Sends a free-form message to user space on the device @wimax_dev.
302 *
303 * NOTES:
304 *
305 * Once the @skb is given to this function, who will own it and will
306 * release it when done (unless it returns error).
307 */
308int wimax_msg(struct wimax_dev *wimax_dev, const char *pipe_name,
309 const void *buf, size_t size, gfp_t gfp_flags)
310{
311 int result = -ENOMEM;
312 struct sk_buff *skb;
313
314 skb = wimax_msg_alloc(wimax_dev, pipe_name, buf, size, gfp_flags);
Inaky Perez-Gonzalezd1a26272009-03-30 17:50:17 -0700315 if (IS_ERR(skb))
316 result = PTR_ERR(skb);
317 else
318 result = wimax_msg_send(wimax_dev, skb);
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800319 return result;
320}
321EXPORT_SYMBOL_GPL(wimax_msg);
322
323
Alexey Dobriyanb54452b2010-02-18 08:14:31 +0000324static const struct nla_policy wimax_gnl_msg_policy[WIMAX_GNL_ATTR_MAX + 1] = {
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800325 [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);
Inaky Perez-Gonzalezde9315f2009-09-30 16:33:26 -0700391 if (result == -ENOMEDIUM)
392 result = 0;
Inaky Perez-Gonzalez3e656462008-12-20 16:57:38 -0800393 if (result < 0)
394 goto error_not_ready;
395 result = -ENOSYS;
396 if (wimax_dev->op_msg_from_user == NULL)
397 goto error_noop;
398
399 d_printf(1, dev,
400 "CRX: nlmsghdr len %u type %u flags 0x%04x seq 0x%x pid %u\n",
401 nlh->nlmsg_len, nlh->nlmsg_type, nlh->nlmsg_flags,
402 nlh->nlmsg_seq, nlh->nlmsg_pid);
403 d_printf(1, dev, "CRX: wimax message %zu bytes\n", msg_len);
404 d_dump(2, dev, msg_buf, msg_len);
405
406 result = wimax_dev->op_msg_from_user(wimax_dev, pipe_name,
407 msg_buf, msg_len, info);
408error_noop:
409error_not_ready:
410 mutex_unlock(&wimax_dev->mutex);
411error_alloc:
412 kfree(pipe_name);
413error_no_data:
414 dev_put(wimax_dev->net_dev);
415error_no_wimax_dev:
416 d_fnend(3, NULL, "(skb %p info %p) = %d\n", skb, info, result);
417 return result;
418}
419
420
421/*
422 * Generic Netlink glue
423 */
424
425struct genl_ops wimax_gnl_msg_from_user = {
426 .cmd = WIMAX_GNL_OP_MSG_FROM_USER,
427 .flags = GENL_ADMIN_PERM,
428 .policy = wimax_gnl_msg_policy,
429 .doit = wimax_gnl_doit_msg_from_user,
430 .dumpit = NULL,
431};
432