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
44static struct batadv_socket_client *batadv_socket_client_hash[256];
45
46static 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 */
53void batadv_socket_init(void)
54{
55	memset(batadv_socket_client_hash, 0, sizeof(batadv_socket_client_hash));
56}
57
58static 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
102static 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
124static 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
164static 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
274dst_unreach:
275	icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
276	batadv_socket_add_packet(socket_client, icmp_header, packet_len);
277free_skb:
278	kfree_skb(skb);
279out:
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
289static __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
301static 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 */
315void 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 */
328static 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 */
384void 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