1 /* Copyright (C) 2007-2017 B.A.T.M.A.N. contributors:
2 *
3 * Marek Lindner
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of version 2 of the GNU General Public
7 * License as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
16 */
17
18 #include "icmp_socket.h"
19 #include "main.h"
20
21 #include <linux/atomic.h>
22 #include <linux/compiler.h>
23 #include <linux/debugfs.h>
24 #include <linux/errno.h>
25 #include <linux/etherdevice.h>
26 #include <linux/export.h>
27 #include <linux/fcntl.h>
28 #include <linux/fs.h>
29 #include <linux/if_ether.h>
30 #include <linux/kernel.h>
31 #include <linux/list.h>
32 #include <linux/module.h>
33 #include <linux/netdevice.h>
34 #include <linux/pkt_sched.h>
35 #include <linux/poll.h>
36 #include <linux/printk.h>
37 #include <linux/sched.h> /* for linux/wait.h */
38 #include <linux/skbuff.h>
39 #include <linux/slab.h>
40 #include <linux/spinlock.h>
41 #include <linux/stddef.h>
42 #include <linux/string.h>
43 #include <linux/uaccess.h>
44 #include <linux/wait.h>
45
46 #include "hard-interface.h"
47 #include "log.h"
48 #include "originator.h"
49 #include "packet.h"
50 #include "send.h"
51
52 static struct batadv_socket_client *batadv_socket_client_hash[256];
53
54 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
55 struct batadv_icmp_header *icmph,
56 size_t icmp_len);
57
batadv_socket_init(void)58 void batadv_socket_init(void)
59 {
60 memset(batadv_socket_client_hash, 0, sizeof(batadv_socket_client_hash));
61 }
62
batadv_socket_open(struct inode * inode,struct file * file)63 static int batadv_socket_open(struct inode *inode, struct file *file)
64 {
65 unsigned int i;
66 struct batadv_socket_client *socket_client;
67
68 if (!try_module_get(THIS_MODULE))
69 return -EBUSY;
70
71 nonseekable_open(inode, file);
72
73 socket_client = kmalloc(sizeof(*socket_client), GFP_KERNEL);
74 if (!socket_client) {
75 module_put(THIS_MODULE);
76 return -ENOMEM;
77 }
78
79 for (i = 0; i < ARRAY_SIZE(batadv_socket_client_hash); i++) {
80 if (!batadv_socket_client_hash[i]) {
81 batadv_socket_client_hash[i] = socket_client;
82 break;
83 }
84 }
85
86 if (i == ARRAY_SIZE(batadv_socket_client_hash)) {
87 pr_err("Error - can't add another packet client: maximum number of clients reached\n");
88 kfree(socket_client);
89 module_put(THIS_MODULE);
90 return -EXFULL;
91 }
92
93 INIT_LIST_HEAD(&socket_client->queue_list);
94 socket_client->queue_len = 0;
95 socket_client->index = i;
96 socket_client->bat_priv = inode->i_private;
97 spin_lock_init(&socket_client->lock);
98 init_waitqueue_head(&socket_client->queue_wait);
99
100 file->private_data = socket_client;
101
102 return 0;
103 }
104
batadv_socket_release(struct inode * inode,struct file * file)105 static int batadv_socket_release(struct inode *inode, struct file *file)
106 {
107 struct batadv_socket_client *client = file->private_data;
108 struct batadv_socket_packet *packet, *tmp;
109
110 spin_lock_bh(&client->lock);
111
112 /* for all packets in the queue ... */
113 list_for_each_entry_safe(packet, tmp, &client->queue_list, list) {
114 list_del(&packet->list);
115 kfree(packet);
116 }
117
118 batadv_socket_client_hash[client->index] = NULL;
119 spin_unlock_bh(&client->lock);
120
121 kfree(client);
122 module_put(THIS_MODULE);
123
124 return 0;
125 }
126
batadv_socket_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)127 static ssize_t batadv_socket_read(struct file *file, char __user *buf,
128 size_t count, loff_t *ppos)
129 {
130 struct batadv_socket_client *socket_client = file->private_data;
131 struct batadv_socket_packet *socket_packet;
132 size_t packet_len;
133 int error;
134
135 if ((file->f_flags & O_NONBLOCK) && (socket_client->queue_len == 0))
136 return -EAGAIN;
137
138 if ((!buf) || (count < sizeof(struct batadv_icmp_packet)))
139 return -EINVAL;
140
141 if (!access_ok(VERIFY_WRITE, buf, count))
142 return -EFAULT;
143
144 error = wait_event_interruptible(socket_client->queue_wait,
145 socket_client->queue_len);
146
147 if (error)
148 return error;
149
150 spin_lock_bh(&socket_client->lock);
151
152 socket_packet = list_first_entry(&socket_client->queue_list,
153 struct batadv_socket_packet, list);
154 list_del(&socket_packet->list);
155 socket_client->queue_len--;
156
157 spin_unlock_bh(&socket_client->lock);
158
159 packet_len = min(count, socket_packet->icmp_len);
160 error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
161
162 kfree(socket_packet);
163
164 if (error)
165 return -EFAULT;
166
167 return packet_len;
168 }
169
batadv_socket_write(struct file * file,const char __user * buff,size_t len,loff_t * off)170 static ssize_t batadv_socket_write(struct file *file, const char __user *buff,
171 size_t len, loff_t *off)
172 {
173 struct batadv_socket_client *socket_client = file->private_data;
174 struct batadv_priv *bat_priv = socket_client->bat_priv;
175 struct batadv_hard_iface *primary_if = NULL;
176 struct sk_buff *skb;
177 struct batadv_icmp_packet_rr *icmp_packet_rr;
178 struct batadv_icmp_header *icmp_header;
179 struct batadv_orig_node *orig_node = NULL;
180 struct batadv_neigh_node *neigh_node = NULL;
181 size_t packet_len = sizeof(struct batadv_icmp_packet);
182 u8 *addr;
183
184 if (len < sizeof(struct batadv_icmp_header)) {
185 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
186 "Error - can't send packet from char device: invalid packet size\n");
187 return -EINVAL;
188 }
189
190 primary_if = batadv_primary_if_get_selected(bat_priv);
191
192 if (!primary_if) {
193 len = -EFAULT;
194 goto out;
195 }
196
197 if (len >= BATADV_ICMP_MAX_PACKET_SIZE)
198 packet_len = BATADV_ICMP_MAX_PACKET_SIZE;
199 else
200 packet_len = len;
201
202 skb = netdev_alloc_skb_ip_align(NULL, packet_len + ETH_HLEN);
203 if (!skb) {
204 len = -ENOMEM;
205 goto out;
206 }
207
208 skb->priority = TC_PRIO_CONTROL;
209 skb_reserve(skb, ETH_HLEN);
210 icmp_header = skb_put(skb, packet_len);
211
212 if (copy_from_user(icmp_header, buff, packet_len)) {
213 len = -EFAULT;
214 goto free_skb;
215 }
216
217 if (icmp_header->packet_type != BATADV_ICMP) {
218 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
219 "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
220 len = -EINVAL;
221 goto free_skb;
222 }
223
224 switch (icmp_header->msg_type) {
225 case BATADV_ECHO_REQUEST:
226 if (len < sizeof(struct batadv_icmp_packet)) {
227 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
228 "Error - can't send packet from char device: invalid packet size\n");
229 len = -EINVAL;
230 goto free_skb;
231 }
232
233 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
234 goto dst_unreach;
235
236 orig_node = batadv_orig_hash_find(bat_priv, icmp_header->dst);
237 if (!orig_node)
238 goto dst_unreach;
239
240 neigh_node = batadv_orig_router_get(orig_node,
241 BATADV_IF_DEFAULT);
242 if (!neigh_node)
243 goto dst_unreach;
244
245 if (!neigh_node->if_incoming)
246 goto dst_unreach;
247
248 if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
249 goto dst_unreach;
250
251 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmp_header;
252 if (packet_len == sizeof(*icmp_packet_rr)) {
253 addr = neigh_node->if_incoming->net_dev->dev_addr;
254 ether_addr_copy(icmp_packet_rr->rr[0], addr);
255 }
256
257 break;
258 default:
259 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
260 "Error - can't send packet from char device: got unknown message type\n");
261 len = -EINVAL;
262 goto free_skb;
263 }
264
265 icmp_header->uid = socket_client->index;
266
267 if (icmp_header->version != BATADV_COMPAT_VERSION) {
268 icmp_header->msg_type = BATADV_PARAMETER_PROBLEM;
269 icmp_header->version = BATADV_COMPAT_VERSION;
270 batadv_socket_add_packet(socket_client, icmp_header,
271 packet_len);
272 goto free_skb;
273 }
274
275 ether_addr_copy(icmp_header->orig, primary_if->net_dev->dev_addr);
276
277 batadv_send_unicast_skb(skb, neigh_node);
278 goto out;
279
280 dst_unreach:
281 icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
282 batadv_socket_add_packet(socket_client, icmp_header, packet_len);
283 free_skb:
284 kfree_skb(skb);
285 out:
286 if (primary_if)
287 batadv_hardif_put(primary_if);
288 if (neigh_node)
289 batadv_neigh_node_put(neigh_node);
290 if (orig_node)
291 batadv_orig_node_put(orig_node);
292 return len;
293 }
294
batadv_socket_poll(struct file * file,poll_table * wait)295 static unsigned int batadv_socket_poll(struct file *file, poll_table *wait)
296 {
297 struct batadv_socket_client *socket_client = file->private_data;
298
299 poll_wait(file, &socket_client->queue_wait, wait);
300
301 if (socket_client->queue_len > 0)
302 return POLLIN | POLLRDNORM;
303
304 return 0;
305 }
306
307 static const struct file_operations batadv_fops = {
308 .owner = THIS_MODULE,
309 .open = batadv_socket_open,
310 .release = batadv_socket_release,
311 .read = batadv_socket_read,
312 .write = batadv_socket_write,
313 .poll = batadv_socket_poll,
314 .llseek = no_llseek,
315 };
316
batadv_socket_setup(struct batadv_priv * bat_priv)317 int batadv_socket_setup(struct batadv_priv *bat_priv)
318 {
319 struct dentry *d;
320
321 if (!bat_priv->debug_dir)
322 goto err;
323
324 d = debugfs_create_file(BATADV_ICMP_SOCKET, 0600, bat_priv->debug_dir,
325 bat_priv, &batadv_fops);
326 if (!d)
327 goto err;
328
329 return 0;
330
331 err:
332 return -ENOMEM;
333 }
334
335 /**
336 * batadv_socket_add_packet - schedule an icmp packet to be sent to
337 * userspace on an icmp socket.
338 * @socket_client: the socket this packet belongs to
339 * @icmph: pointer to the header of the icmp packet
340 * @icmp_len: total length of the icmp packet
341 */
batadv_socket_add_packet(struct batadv_socket_client * socket_client,struct batadv_icmp_header * icmph,size_t icmp_len)342 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
343 struct batadv_icmp_header *icmph,
344 size_t icmp_len)
345 {
346 struct batadv_socket_packet *socket_packet;
347 size_t len;
348
349 socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
350
351 if (!socket_packet)
352 return;
353
354 len = icmp_len;
355 /* check the maximum length before filling the buffer */
356 if (len > sizeof(socket_packet->icmp_packet))
357 len = sizeof(socket_packet->icmp_packet);
358
359 INIT_LIST_HEAD(&socket_packet->list);
360 memcpy(&socket_packet->icmp_packet, icmph, len);
361 socket_packet->icmp_len = len;
362
363 spin_lock_bh(&socket_client->lock);
364
365 /* while waiting for the lock the socket_client could have been
366 * deleted
367 */
368 if (!batadv_socket_client_hash[icmph->uid]) {
369 spin_unlock_bh(&socket_client->lock);
370 kfree(socket_packet);
371 return;
372 }
373
374 list_add_tail(&socket_packet->list, &socket_client->queue_list);
375 socket_client->queue_len++;
376
377 if (socket_client->queue_len > 100) {
378 socket_packet = list_first_entry(&socket_client->queue_list,
379 struct batadv_socket_packet,
380 list);
381
382 list_del(&socket_packet->list);
383 kfree(socket_packet);
384 socket_client->queue_len--;
385 }
386
387 spin_unlock_bh(&socket_client->lock);
388
389 wake_up(&socket_client->queue_wait);
390 }
391
392 /**
393 * batadv_socket_receive_packet - schedule an icmp packet to be received
394 * locally and sent to userspace.
395 * @icmph: pointer to the header of the icmp packet
396 * @icmp_len: total length of the icmp packet
397 */
batadv_socket_receive_packet(struct batadv_icmp_header * icmph,size_t icmp_len)398 void batadv_socket_receive_packet(struct batadv_icmp_header *icmph,
399 size_t icmp_len)
400 {
401 struct batadv_socket_client *hash;
402
403 hash = batadv_socket_client_hash[icmph->uid];
404 if (hash)
405 batadv_socket_add_packet(hash, icmph, icmp_len);
406 }
407