1/* Copyright (C) 2007-2014 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 "main.h"
19#include <linux/debugfs.h>
20#include <linux/slab.h>
21#include "icmp_socket.h"
22#include "send.h"
23#include "hash.h"
24#include "originator.h"
25#include "hard-interface.h"
26
27static struct batadv_socket_client *batadv_socket_client_hash[256];
28
29static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
30				     struct batadv_icmp_header *icmph,
31				     size_t icmp_len);
32
33void batadv_socket_init(void)
34{
35	memset(batadv_socket_client_hash, 0, sizeof(batadv_socket_client_hash));
36}
37
38static int batadv_socket_open(struct inode *inode, struct file *file)
39{
40	unsigned int i;
41	struct batadv_socket_client *socket_client;
42
43	if (!try_module_get(THIS_MODULE))
44		return -EBUSY;
45
46	nonseekable_open(inode, file);
47
48	socket_client = kmalloc(sizeof(*socket_client), GFP_KERNEL);
49	if (!socket_client) {
50		module_put(THIS_MODULE);
51		return -ENOMEM;
52	}
53
54	for (i = 0; i < ARRAY_SIZE(batadv_socket_client_hash); i++) {
55		if (!batadv_socket_client_hash[i]) {
56			batadv_socket_client_hash[i] = socket_client;
57			break;
58		}
59	}
60
61	if (i == ARRAY_SIZE(batadv_socket_client_hash)) {
62		pr_err("Error - can't add another packet client: maximum number of clients reached\n");
63		kfree(socket_client);
64		module_put(THIS_MODULE);
65		return -EXFULL;
66	}
67
68	INIT_LIST_HEAD(&socket_client->queue_list);
69	socket_client->queue_len = 0;
70	socket_client->index = i;
71	socket_client->bat_priv = inode->i_private;
72	spin_lock_init(&socket_client->lock);
73	init_waitqueue_head(&socket_client->queue_wait);
74
75	file->private_data = socket_client;
76
77	return 0;
78}
79
80static int batadv_socket_release(struct inode *inode, struct file *file)
81{
82	struct batadv_socket_client *socket_client = file->private_data;
83	struct batadv_socket_packet *socket_packet;
84	struct list_head *list_pos, *list_pos_tmp;
85
86	spin_lock_bh(&socket_client->lock);
87
88	/* for all packets in the queue ... */
89	list_for_each_safe(list_pos, list_pos_tmp, &socket_client->queue_list) {
90		socket_packet = list_entry(list_pos,
91					   struct batadv_socket_packet, list);
92
93		list_del(list_pos);
94		kfree(socket_packet);
95	}
96
97	batadv_socket_client_hash[socket_client->index] = NULL;
98	spin_unlock_bh(&socket_client->lock);
99
100	kfree(socket_client);
101	module_put(THIS_MODULE);
102
103	return 0;
104}
105
106static ssize_t batadv_socket_read(struct file *file, char __user *buf,
107				  size_t count, loff_t *ppos)
108{
109	struct batadv_socket_client *socket_client = file->private_data;
110	struct batadv_socket_packet *socket_packet;
111	size_t packet_len;
112	int error;
113
114	if ((file->f_flags & O_NONBLOCK) && (socket_client->queue_len == 0))
115		return -EAGAIN;
116
117	if ((!buf) || (count < sizeof(struct batadv_icmp_packet)))
118		return -EINVAL;
119
120	if (!access_ok(VERIFY_WRITE, buf, count))
121		return -EFAULT;
122
123	error = wait_event_interruptible(socket_client->queue_wait,
124					 socket_client->queue_len);
125
126	if (error)
127		return error;
128
129	spin_lock_bh(&socket_client->lock);
130
131	socket_packet = list_first_entry(&socket_client->queue_list,
132					 struct batadv_socket_packet, list);
133	list_del(&socket_packet->list);
134	socket_client->queue_len--;
135
136	spin_unlock_bh(&socket_client->lock);
137
138	packet_len = min(count, socket_packet->icmp_len);
139	error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
140
141	kfree(socket_packet);
142
143	if (error)
144		return -EFAULT;
145
146	return packet_len;
147}
148
149static ssize_t batadv_socket_write(struct file *file, const char __user *buff,
150				   size_t len, loff_t *off)
151{
152	struct batadv_socket_client *socket_client = file->private_data;
153	struct batadv_priv *bat_priv = socket_client->bat_priv;
154	struct batadv_hard_iface *primary_if = NULL;
155	struct sk_buff *skb;
156	struct batadv_icmp_packet_rr *icmp_packet_rr;
157	struct batadv_icmp_header *icmp_header;
158	struct batadv_orig_node *orig_node = NULL;
159	struct batadv_neigh_node *neigh_node = NULL;
160	size_t packet_len = sizeof(struct batadv_icmp_packet);
161	uint8_t *addr;
162
163	if (len < sizeof(struct batadv_icmp_header)) {
164		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
165			   "Error - can't send packet from char device: invalid packet size\n");
166		return -EINVAL;
167	}
168
169	primary_if = batadv_primary_if_get_selected(bat_priv);
170
171	if (!primary_if) {
172		len = -EFAULT;
173		goto out;
174	}
175
176	if (len >= BATADV_ICMP_MAX_PACKET_SIZE)
177		packet_len = BATADV_ICMP_MAX_PACKET_SIZE;
178	else
179		packet_len = len;
180
181	skb = netdev_alloc_skb_ip_align(NULL, packet_len + ETH_HLEN);
182	if (!skb) {
183		len = -ENOMEM;
184		goto out;
185	}
186
187	skb->priority = TC_PRIO_CONTROL;
188	skb_reserve(skb, ETH_HLEN);
189	icmp_header = (struct batadv_icmp_header *)skb_put(skb, packet_len);
190
191	if (copy_from_user(icmp_header, buff, packet_len)) {
192		len = -EFAULT;
193		goto free_skb;
194	}
195
196	if (icmp_header->packet_type != BATADV_ICMP) {
197		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
198			   "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
199		len = -EINVAL;
200		goto free_skb;
201	}
202
203	switch (icmp_header->msg_type) {
204	case BATADV_ECHO_REQUEST:
205		if (len < sizeof(struct batadv_icmp_packet)) {
206			batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
207				   "Error - can't send packet from char device: invalid packet size\n");
208			len = -EINVAL;
209			goto free_skb;
210		}
211
212		if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
213			goto dst_unreach;
214
215		orig_node = batadv_orig_hash_find(bat_priv, icmp_header->dst);
216		if (!orig_node)
217			goto dst_unreach;
218
219		neigh_node = batadv_orig_router_get(orig_node,
220						    BATADV_IF_DEFAULT);
221		if (!neigh_node)
222			goto dst_unreach;
223
224		if (!neigh_node->if_incoming)
225			goto dst_unreach;
226
227		if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
228			goto dst_unreach;
229
230		icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmp_header;
231		if (packet_len == sizeof(*icmp_packet_rr)) {
232			addr = neigh_node->if_incoming->net_dev->dev_addr;
233			ether_addr_copy(icmp_packet_rr->rr[0], addr);
234		}
235
236		break;
237	default:
238		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
239			   "Error - can't send packet from char device: got unknown message type\n");
240		len = -EINVAL;
241		goto free_skb;
242	}
243
244	icmp_header->uid = socket_client->index;
245
246	if (icmp_header->version != BATADV_COMPAT_VERSION) {
247		icmp_header->msg_type = BATADV_PARAMETER_PROBLEM;
248		icmp_header->version = BATADV_COMPAT_VERSION;
249		batadv_socket_add_packet(socket_client, icmp_header,
250					 packet_len);
251		goto free_skb;
252	}
253
254	ether_addr_copy(icmp_header->orig, primary_if->net_dev->dev_addr);
255
256	batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
257	goto out;
258
259dst_unreach:
260	icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
261	batadv_socket_add_packet(socket_client, icmp_header, packet_len);
262free_skb:
263	kfree_skb(skb);
264out:
265	if (primary_if)
266		batadv_hardif_free_ref(primary_if);
267	if (neigh_node)
268		batadv_neigh_node_free_ref(neigh_node);
269	if (orig_node)
270		batadv_orig_node_free_ref(orig_node);
271	return len;
272}
273
274static unsigned int batadv_socket_poll(struct file *file, poll_table *wait)
275{
276	struct batadv_socket_client *socket_client = file->private_data;
277
278	poll_wait(file, &socket_client->queue_wait, wait);
279
280	if (socket_client->queue_len > 0)
281		return POLLIN | POLLRDNORM;
282
283	return 0;
284}
285
286static const struct file_operations batadv_fops = {
287	.owner = THIS_MODULE,
288	.open = batadv_socket_open,
289	.release = batadv_socket_release,
290	.read = batadv_socket_read,
291	.write = batadv_socket_write,
292	.poll = batadv_socket_poll,
293	.llseek = no_llseek,
294};
295
296int batadv_socket_setup(struct batadv_priv *bat_priv)
297{
298	struct dentry *d;
299
300	if (!bat_priv->debug_dir)
301		goto err;
302
303	d = debugfs_create_file(BATADV_ICMP_SOCKET, S_IFREG | S_IWUSR | S_IRUSR,
304				bat_priv->debug_dir, bat_priv, &batadv_fops);
305	if (!d)
306		goto err;
307
308	return 0;
309
310err:
311	return -ENOMEM;
312}
313
314/**
315 * batadv_socket_receive_packet - schedule an icmp packet to be sent to userspace
316 *  on an icmp socket.
317 * @socket_client: the socket this packet belongs to
318 * @icmph: pointer to the header of the icmp packet
319 * @icmp_len: total length of the icmp packet
320 */
321static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
322				     struct batadv_icmp_header *icmph,
323				     size_t icmp_len)
324{
325	struct batadv_socket_packet *socket_packet;
326	size_t len;
327
328	socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
329
330	if (!socket_packet)
331		return;
332
333	len = icmp_len;
334	/* check the maximum length before filling the buffer */
335	if (len > sizeof(socket_packet->icmp_packet))
336		len = sizeof(socket_packet->icmp_packet);
337
338	INIT_LIST_HEAD(&socket_packet->list);
339	memcpy(&socket_packet->icmp_packet, icmph, len);
340	socket_packet->icmp_len = len;
341
342	spin_lock_bh(&socket_client->lock);
343
344	/* while waiting for the lock the socket_client could have been
345	 * deleted
346	 */
347	if (!batadv_socket_client_hash[icmph->uid]) {
348		spin_unlock_bh(&socket_client->lock);
349		kfree(socket_packet);
350		return;
351	}
352
353	list_add_tail(&socket_packet->list, &socket_client->queue_list);
354	socket_client->queue_len++;
355
356	if (socket_client->queue_len > 100) {
357		socket_packet = list_first_entry(&socket_client->queue_list,
358						 struct batadv_socket_packet,
359						 list);
360
361		list_del(&socket_packet->list);
362		kfree(socket_packet);
363		socket_client->queue_len--;
364	}
365
366	spin_unlock_bh(&socket_client->lock);
367
368	wake_up(&socket_client->queue_wait);
369}
370
371/**
372 * batadv_socket_receive_packet - schedule an icmp packet to be received
373 *  locally and sent to userspace.
374 * @icmph: pointer to the header of the icmp packet
375 * @icmp_len: total length of the icmp packet
376 */
377void batadv_socket_receive_packet(struct batadv_icmp_header *icmph,
378				  size_t icmp_len)
379{
380	struct batadv_socket_client *hash;
381
382	hash = batadv_socket_client_hash[icmph->uid];
383	if (hash)
384		batadv_socket_add_packet(hash, icmph, icmp_len);
385}
386