• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2007-2020  B.A.T.M.A.N. contributors:
3  *
4  * Marek Lindner
5  */
6 
7 #include "icmp_socket.h"
8 #include "main.h"
9 
10 #include <linux/atomic.h>
11 #include <linux/compiler.h>
12 #include <linux/debugfs.h>
13 #include <linux/errno.h>
14 #include <linux/etherdevice.h>
15 #include <linux/eventpoll.h>
16 #include <linux/export.h>
17 #include <linux/fcntl.h>
18 #include <linux/fs.h>
19 #include <linux/gfp.h>
20 #include <linux/if_ether.h>
21 #include <linux/kernel.h>
22 #include <linux/list.h>
23 #include <linux/module.h>
24 #include <linux/netdevice.h>
25 #include <linux/pkt_sched.h>
26 #include <linux/poll.h>
27 #include <linux/printk.h>
28 #include <linux/sched.h> /* for linux/wait.h */
29 #include <linux/skbuff.h>
30 #include <linux/slab.h>
31 #include <linux/spinlock.h>
32 #include <linux/stddef.h>
33 #include <linux/string.h>
34 #include <linux/uaccess.h>
35 #include <linux/wait.h>
36 #include <uapi/linux/batadv_packet.h>
37 
38 #include "debugfs.h"
39 #include "hard-interface.h"
40 #include "log.h"
41 #include "originator.h"
42 #include "send.h"
43 
44 static struct batadv_socket_client *batadv_socket_client_hash[256];
45 
46 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
47 				     struct batadv_icmp_header *icmph,
48 				     size_t icmp_len);
49 
50 /**
51  * batadv_socket_init() - Initialize soft interface independent socket data
52  */
batadv_socket_init(void)53 void batadv_socket_init(void)
54 {
55 	memset(batadv_socket_client_hash, 0, sizeof(batadv_socket_client_hash));
56 }
57 
batadv_socket_open(struct inode * inode,struct file * file)58 static int batadv_socket_open(struct inode *inode, struct file *file)
59 {
60 	unsigned int i;
61 	struct batadv_socket_client *socket_client;
62 
63 	if (!try_module_get(THIS_MODULE))
64 		return -EBUSY;
65 
66 	batadv_debugfs_deprecated(file, "");
67 
68 	stream_open(inode, file);
69 
70 	socket_client = kmalloc(sizeof(*socket_client), GFP_KERNEL);
71 	if (!socket_client) {
72 		module_put(THIS_MODULE);
73 		return -ENOMEM;
74 	}
75 
76 	for (i = 0; i < ARRAY_SIZE(batadv_socket_client_hash); i++) {
77 		if (!batadv_socket_client_hash[i]) {
78 			batadv_socket_client_hash[i] = socket_client;
79 			break;
80 		}
81 	}
82 
83 	if (i == ARRAY_SIZE(batadv_socket_client_hash)) {
84 		pr_err("Error - can't add another packet client: maximum number of clients reached\n");
85 		kfree(socket_client);
86 		module_put(THIS_MODULE);
87 		return -EXFULL;
88 	}
89 
90 	INIT_LIST_HEAD(&socket_client->queue_list);
91 	socket_client->queue_len = 0;
92 	socket_client->index = i;
93 	socket_client->bat_priv = inode->i_private;
94 	spin_lock_init(&socket_client->lock);
95 	init_waitqueue_head(&socket_client->queue_wait);
96 
97 	file->private_data = socket_client;
98 
99 	return 0;
100 }
101 
batadv_socket_release(struct inode * inode,struct file * file)102 static int batadv_socket_release(struct inode *inode, struct file *file)
103 {
104 	struct batadv_socket_client *client = file->private_data;
105 	struct batadv_socket_packet *packet, *tmp;
106 
107 	spin_lock_bh(&client->lock);
108 
109 	/* for all packets in the queue ... */
110 	list_for_each_entry_safe(packet, tmp, &client->queue_list, list) {
111 		list_del(&packet->list);
112 		kfree(packet);
113 	}
114 
115 	batadv_socket_client_hash[client->index] = NULL;
116 	spin_unlock_bh(&client->lock);
117 
118 	kfree(client);
119 	module_put(THIS_MODULE);
120 
121 	return 0;
122 }
123 
batadv_socket_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)124 static ssize_t batadv_socket_read(struct file *file, char __user *buf,
125 				  size_t count, loff_t *ppos)
126 {
127 	struct batadv_socket_client *socket_client = file->private_data;
128 	struct batadv_socket_packet *socket_packet;
129 	size_t packet_len;
130 	int error;
131 
132 	if ((file->f_flags & O_NONBLOCK) && socket_client->queue_len == 0)
133 		return -EAGAIN;
134 
135 	if (!buf || count < sizeof(struct batadv_icmp_packet))
136 		return -EINVAL;
137 
138 	error = wait_event_interruptible(socket_client->queue_wait,
139 					 socket_client->queue_len);
140 
141 	if (error)
142 		return error;
143 
144 	spin_lock_bh(&socket_client->lock);
145 
146 	socket_packet = list_first_entry(&socket_client->queue_list,
147 					 struct batadv_socket_packet, list);
148 	list_del(&socket_packet->list);
149 	socket_client->queue_len--;
150 
151 	spin_unlock_bh(&socket_client->lock);
152 
153 	packet_len = min(count, socket_packet->icmp_len);
154 	error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
155 
156 	kfree(socket_packet);
157 
158 	if (error)
159 		return -EFAULT;
160 
161 	return packet_len;
162 }
163 
batadv_socket_write(struct file * file,const char __user * buff,size_t len,loff_t * off)164 static ssize_t batadv_socket_write(struct file *file, const char __user *buff,
165 				   size_t len, loff_t *off)
166 {
167 	struct batadv_socket_client *socket_client = file->private_data;
168 	struct batadv_priv *bat_priv = socket_client->bat_priv;
169 	struct batadv_hard_iface *primary_if = NULL;
170 	struct sk_buff *skb;
171 	struct batadv_icmp_packet_rr *icmp_packet_rr;
172 	struct batadv_icmp_header *icmp_header;
173 	struct batadv_orig_node *orig_node = NULL;
174 	struct batadv_neigh_node *neigh_node = NULL;
175 	size_t packet_len = sizeof(struct batadv_icmp_packet);
176 	u8 *addr;
177 
178 	if (len < sizeof(struct batadv_icmp_header)) {
179 		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
180 			   "Error - can't send packet from char device: invalid packet size\n");
181 		return -EINVAL;
182 	}
183 
184 	primary_if = batadv_primary_if_get_selected(bat_priv);
185 
186 	if (!primary_if) {
187 		len = -EFAULT;
188 		goto out;
189 	}
190 
191 	if (len >= BATADV_ICMP_MAX_PACKET_SIZE)
192 		packet_len = BATADV_ICMP_MAX_PACKET_SIZE;
193 	else
194 		packet_len = len;
195 
196 	skb = netdev_alloc_skb_ip_align(NULL, packet_len + ETH_HLEN);
197 	if (!skb) {
198 		len = -ENOMEM;
199 		goto out;
200 	}
201 
202 	skb->priority = TC_PRIO_CONTROL;
203 	skb_reserve(skb, ETH_HLEN);
204 	icmp_header = skb_put(skb, packet_len);
205 
206 	if (copy_from_user(icmp_header, buff, packet_len)) {
207 		len = -EFAULT;
208 		goto free_skb;
209 	}
210 
211 	if (icmp_header->packet_type != BATADV_ICMP) {
212 		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
213 			   "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
214 		len = -EINVAL;
215 		goto free_skb;
216 	}
217 
218 	switch (icmp_header->msg_type) {
219 	case BATADV_ECHO_REQUEST:
220 		if (len < sizeof(struct batadv_icmp_packet)) {
221 			batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
222 				   "Error - can't send packet from char device: invalid packet size\n");
223 			len = -EINVAL;
224 			goto free_skb;
225 		}
226 
227 		if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
228 			goto dst_unreach;
229 
230 		orig_node = batadv_orig_hash_find(bat_priv, icmp_header->dst);
231 		if (!orig_node)
232 			goto dst_unreach;
233 
234 		neigh_node = batadv_orig_router_get(orig_node,
235 						    BATADV_IF_DEFAULT);
236 		if (!neigh_node)
237 			goto dst_unreach;
238 
239 		if (!neigh_node->if_incoming)
240 			goto dst_unreach;
241 
242 		if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
243 			goto dst_unreach;
244 
245 		icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmp_header;
246 		if (packet_len == sizeof(*icmp_packet_rr)) {
247 			addr = neigh_node->if_incoming->net_dev->dev_addr;
248 			ether_addr_copy(icmp_packet_rr->rr[0], addr);
249 		}
250 
251 		break;
252 	default:
253 		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
254 			   "Error - can't send packet from char device: got unknown message type\n");
255 		len = -EINVAL;
256 		goto free_skb;
257 	}
258 
259 	icmp_header->uid = socket_client->index;
260 
261 	if (icmp_header->version != BATADV_COMPAT_VERSION) {
262 		icmp_header->msg_type = BATADV_PARAMETER_PROBLEM;
263 		icmp_header->version = BATADV_COMPAT_VERSION;
264 		batadv_socket_add_packet(socket_client, icmp_header,
265 					 packet_len);
266 		goto free_skb;
267 	}
268 
269 	ether_addr_copy(icmp_header->orig, primary_if->net_dev->dev_addr);
270 
271 	batadv_send_unicast_skb(skb, neigh_node);
272 	goto out;
273 
274 dst_unreach:
275 	icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
276 	batadv_socket_add_packet(socket_client, icmp_header, packet_len);
277 free_skb:
278 	kfree_skb(skb);
279 out:
280 	if (primary_if)
281 		batadv_hardif_put(primary_if);
282 	if (neigh_node)
283 		batadv_neigh_node_put(neigh_node);
284 	if (orig_node)
285 		batadv_orig_node_put(orig_node);
286 	return len;
287 }
288 
batadv_socket_poll(struct file * file,poll_table * wait)289 static __poll_t batadv_socket_poll(struct file *file, poll_table *wait)
290 {
291 	struct batadv_socket_client *socket_client = file->private_data;
292 
293 	poll_wait(file, &socket_client->queue_wait, wait);
294 
295 	if (socket_client->queue_len > 0)
296 		return EPOLLIN | EPOLLRDNORM;
297 
298 	return 0;
299 }
300 
301 static const struct file_operations batadv_fops = {
302 	.owner = THIS_MODULE,
303 	.open = batadv_socket_open,
304 	.release = batadv_socket_release,
305 	.read = batadv_socket_read,
306 	.write = batadv_socket_write,
307 	.poll = batadv_socket_poll,
308 	.llseek = no_llseek,
309 };
310 
311 /**
312  * batadv_socket_setup() - Create debugfs "socket" file
313  * @bat_priv: the bat priv with all the soft interface information
314  */
batadv_socket_setup(struct batadv_priv * bat_priv)315 void batadv_socket_setup(struct batadv_priv *bat_priv)
316 {
317 	debugfs_create_file(BATADV_ICMP_SOCKET, 0600, bat_priv->debug_dir,
318 			    bat_priv, &batadv_fops);
319 }
320 
321 /**
322  * batadv_socket_add_packet() - schedule an icmp packet to be sent to
323  *  userspace on an icmp socket.
324  * @socket_client: the socket this packet belongs to
325  * @icmph: pointer to the header of the icmp packet
326  * @icmp_len: total length of the icmp packet
327  */
batadv_socket_add_packet(struct batadv_socket_client * socket_client,struct batadv_icmp_header * icmph,size_t icmp_len)328 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
329 				     struct batadv_icmp_header *icmph,
330 				     size_t icmp_len)
331 {
332 	struct batadv_socket_packet *socket_packet;
333 	size_t len;
334 
335 	socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
336 
337 	if (!socket_packet)
338 		return;
339 
340 	len = icmp_len;
341 	/* check the maximum length before filling the buffer */
342 	if (len > sizeof(socket_packet->icmp_packet))
343 		len = sizeof(socket_packet->icmp_packet);
344 
345 	INIT_LIST_HEAD(&socket_packet->list);
346 	memcpy(&socket_packet->icmp_packet, icmph, len);
347 	socket_packet->icmp_len = len;
348 
349 	spin_lock_bh(&socket_client->lock);
350 
351 	/* while waiting for the lock the socket_client could have been
352 	 * deleted
353 	 */
354 	if (!batadv_socket_client_hash[icmph->uid]) {
355 		spin_unlock_bh(&socket_client->lock);
356 		kfree(socket_packet);
357 		return;
358 	}
359 
360 	list_add_tail(&socket_packet->list, &socket_client->queue_list);
361 	socket_client->queue_len++;
362 
363 	if (socket_client->queue_len > 100) {
364 		socket_packet = list_first_entry(&socket_client->queue_list,
365 						 struct batadv_socket_packet,
366 						 list);
367 
368 		list_del(&socket_packet->list);
369 		kfree(socket_packet);
370 		socket_client->queue_len--;
371 	}
372 
373 	spin_unlock_bh(&socket_client->lock);
374 
375 	wake_up(&socket_client->queue_wait);
376 }
377 
378 /**
379  * batadv_socket_receive_packet() - schedule an icmp packet to be received
380  *  locally and sent to userspace.
381  * @icmph: pointer to the header of the icmp packet
382  * @icmp_len: total length of the icmp packet
383  */
batadv_socket_receive_packet(struct batadv_icmp_header * icmph,size_t icmp_len)384 void batadv_socket_receive_packet(struct batadv_icmp_header *icmph,
385 				  size_t icmp_len)
386 {
387 	struct batadv_socket_client *hash;
388 
389 	hash = batadv_socket_client_hash[icmph->uid];
390 	if (hash)
391 		batadv_socket_add_packet(hash, icmph, icmp_len);
392 }
393