1 /*
2  * net/tipc/discover.c
3  *
4  * Copyright (c) 2003-2006, 2014-2018, Ericsson AB
5  * Copyright (c) 2005-2006, 2010-2011, Wind River Systems
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the names of the copyright holders nor the names of its
17  *    contributors may be used to endorse or promote products derived from
18  *    this software without specific prior written permission.
19  *
20  * Alternatively, this software may be distributed under the terms of the
21  * GNU General Public License ("GPL") version 2 as published by the Free
22  * Software Foundation.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36 
37 #include "core.h"
38 #include "node.h"
39 #include "discover.h"
40 
41 /* min delay during bearer start up */
42 #define TIPC_DISC_INIT	msecs_to_jiffies(125)
43 /* max delay if bearer has no links */
44 #define TIPC_DISC_FAST	msecs_to_jiffies(1000)
45 /* max delay if bearer has links */
46 #define TIPC_DISC_SLOW	msecs_to_jiffies(60000)
47 /* indicates no timer in use */
48 #define TIPC_DISC_INACTIVE	0xffffffff
49 
50 /**
51  * struct tipc_discoverer - information about an ongoing link setup request
52  * @bearer_id: identity of bearer issuing requests
53  * @net: network namespace instance
54  * @dest: destination address for request messages
55  * @domain: network domain to which links can be established
56  * @num_nodes: number of nodes currently discovered (i.e. with an active link)
57  * @lock: spinlock for controlling access to requests
58  * @skb: request message to be (repeatedly) sent
59  * @timer: timer governing period between requests
60  * @timer_intv: current interval between requests (in ms)
61  */
62 struct tipc_discoverer {
63 	u32 bearer_id;
64 	struct tipc_media_addr dest;
65 	struct net *net;
66 	u32 domain;
67 	int num_nodes;
68 	spinlock_t lock;
69 	struct sk_buff *skb;
70 	struct timer_list timer;
71 	unsigned long timer_intv;
72 };
73 
74 /**
75  * tipc_disc_init_msg - initialize a link setup message
76  * @net: the applicable net namespace
77  * @skb: buffer containing message
78  * @mtyp: message type (request or response)
79  * @b: ptr to bearer issuing message
80  */
tipc_disc_init_msg(struct net * net,struct sk_buff * skb,u32 mtyp,struct tipc_bearer * b)81 static void tipc_disc_init_msg(struct net *net, struct sk_buff *skb,
82 			       u32 mtyp,  struct tipc_bearer *b)
83 {
84 	struct tipc_net *tn = tipc_net(net);
85 	u32 dest_domain = b->domain;
86 	struct tipc_msg *hdr;
87 
88 	hdr = buf_msg(skb);
89 	tipc_msg_init(tn->trial_addr, hdr, LINK_CONFIG, mtyp,
90 		      MAX_H_SIZE, dest_domain);
91 	msg_set_size(hdr, MAX_H_SIZE + NODE_ID_LEN);
92 	msg_set_non_seq(hdr, 1);
93 	msg_set_node_sig(hdr, tn->random);
94 	msg_set_node_capabilities(hdr, TIPC_NODE_CAPABILITIES);
95 	msg_set_dest_domain(hdr, dest_domain);
96 	msg_set_bc_netid(hdr, tn->net_id);
97 	b->media->addr2msg(msg_media_addr(hdr), &b->addr);
98 	msg_set_peer_net_hash(hdr, tipc_net_hash_mixes(net, tn->random));
99 	msg_set_node_id(hdr, tipc_own_id(net));
100 }
101 
tipc_disc_msg_xmit(struct net * net,u32 mtyp,u32 dst,u32 src,u32 sugg_addr,struct tipc_media_addr * maddr,struct tipc_bearer * b)102 static void tipc_disc_msg_xmit(struct net *net, u32 mtyp, u32 dst,
103 			       u32 src, u32 sugg_addr,
104 			       struct tipc_media_addr *maddr,
105 			       struct tipc_bearer *b)
106 {
107 	struct tipc_msg *hdr;
108 	struct sk_buff *skb;
109 
110 	skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
111 	if (!skb)
112 		return;
113 	hdr = buf_msg(skb);
114 	tipc_disc_init_msg(net, skb, mtyp, b);
115 	msg_set_sugg_node_addr(hdr, sugg_addr);
116 	msg_set_dest_domain(hdr, dst);
117 	tipc_bearer_xmit_skb(net, b->identity, skb, maddr);
118 }
119 
120 /**
121  * disc_dupl_alert - issue node address duplication alert
122  * @b: pointer to bearer detecting duplication
123  * @node_addr: duplicated node address
124  * @media_addr: media address advertised by duplicated node
125  */
disc_dupl_alert(struct tipc_bearer * b,u32 node_addr,struct tipc_media_addr * media_addr)126 static void disc_dupl_alert(struct tipc_bearer *b, u32 node_addr,
127 			    struct tipc_media_addr *media_addr)
128 {
129 	char media_addr_str[64];
130 
131 	tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str),
132 			       media_addr);
133 	pr_warn("Duplicate %x using %s seen on <%s>\n", node_addr,
134 		media_addr_str, b->name);
135 }
136 
137 /* tipc_disc_addr_trial(): - handle an address uniqueness trial from peer
138  * Returns true if message should be dropped by caller, i.e., if it is a
139  * trial message or we are inside trial period. Otherwise false.
140  */
tipc_disc_addr_trial_msg(struct tipc_discoverer * d,struct tipc_media_addr * maddr,struct tipc_bearer * b,u32 dst,u32 src,u32 sugg_addr,u8 * peer_id,int mtyp)141 static bool tipc_disc_addr_trial_msg(struct tipc_discoverer *d,
142 				     struct tipc_media_addr *maddr,
143 				     struct tipc_bearer *b,
144 				     u32 dst, u32 src,
145 				     u32 sugg_addr,
146 				     u8 *peer_id,
147 				     int mtyp)
148 {
149 	struct net *net = d->net;
150 	struct tipc_net *tn = tipc_net(net);
151 	bool trial = time_before(jiffies, tn->addr_trial_end);
152 	u32 self = tipc_own_addr(net);
153 
154 	if (mtyp == DSC_TRIAL_FAIL_MSG) {
155 		if (!trial)
156 			return true;
157 
158 		/* Ignore if somebody else already gave new suggestion */
159 		if (dst != tn->trial_addr)
160 			return true;
161 
162 		/* Otherwise update trial address and restart trial period */
163 		tn->trial_addr = sugg_addr;
164 		msg_set_prevnode(buf_msg(d->skb), sugg_addr);
165 		tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
166 		return true;
167 	}
168 
169 	/* Apply trial address if we just left trial period */
170 	if (!trial && !self) {
171 		schedule_work(&tn->work);
172 		msg_set_prevnode(buf_msg(d->skb), tn->trial_addr);
173 		msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
174 	}
175 
176 	/* Accept regular link requests/responses only after trial period */
177 	if (mtyp != DSC_TRIAL_MSG)
178 		return trial;
179 
180 	sugg_addr = tipc_node_try_addr(net, peer_id, src);
181 	if (sugg_addr)
182 		tipc_disc_msg_xmit(net, DSC_TRIAL_FAIL_MSG, src,
183 				   self, sugg_addr, maddr, b);
184 	return true;
185 }
186 
187 /**
188  * tipc_disc_rcv - handle incoming discovery message (request or response)
189  * @net: applicable net namespace
190  * @skb: buffer containing message
191  * @b: bearer that message arrived on
192  */
tipc_disc_rcv(struct net * net,struct sk_buff * skb,struct tipc_bearer * b)193 void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
194 		   struct tipc_bearer *b)
195 {
196 	struct tipc_net *tn = tipc_net(net);
197 	struct tipc_msg *hdr = buf_msg(skb);
198 	u32 pnet_hash = msg_peer_net_hash(hdr);
199 	u16 caps = msg_node_capabilities(hdr);
200 	bool legacy = tn->legacy_addr_format;
201 	u32 sugg = msg_sugg_node_addr(hdr);
202 	u32 signature = msg_node_sig(hdr);
203 	u8 peer_id[NODE_ID_LEN] = {0,};
204 	u32 dst = msg_dest_domain(hdr);
205 	u32 net_id = msg_bc_netid(hdr);
206 	struct tipc_media_addr maddr;
207 	u32 src = msg_prevnode(hdr);
208 	u32 mtyp = msg_type(hdr);
209 	bool dupl_addr = false;
210 	bool respond = false;
211 	u32 self;
212 	int err;
213 
214 	skb_linearize(skb);
215 	hdr = buf_msg(skb);
216 
217 	if (caps & TIPC_NODE_ID128)
218 		memcpy(peer_id, msg_node_id(hdr), NODE_ID_LEN);
219 	else
220 		sprintf(peer_id, "%x", src);
221 
222 	err = b->media->msg2addr(b, &maddr, msg_media_addr(hdr));
223 	kfree_skb(skb);
224 	if (err || maddr.broadcast) {
225 		pr_warn_ratelimited("Rcv corrupt discovery message\n");
226 		return;
227 	}
228 	/* Ignore discovery messages from own node */
229 	if (!memcmp(&maddr, &b->addr, sizeof(maddr)))
230 		return;
231 	if (net_id != tn->net_id)
232 		return;
233 	if (tipc_disc_addr_trial_msg(b->disc, &maddr, b, dst,
234 				     src, sugg, peer_id, mtyp))
235 		return;
236 	self = tipc_own_addr(net);
237 
238 	/* Message from somebody using this node's address */
239 	if (in_own_node(net, src)) {
240 		disc_dupl_alert(b, self, &maddr);
241 		return;
242 	}
243 	if (!tipc_in_scope(legacy, dst, self))
244 		return;
245 	if (!tipc_in_scope(legacy, b->domain, src))
246 		return;
247 	tipc_node_check_dest(net, src, peer_id, b, caps, signature, pnet_hash,
248 			     &maddr, &respond, &dupl_addr);
249 	if (dupl_addr)
250 		disc_dupl_alert(b, src, &maddr);
251 	if (!respond)
252 		return;
253 	if (mtyp != DSC_REQ_MSG)
254 		return;
255 	tipc_disc_msg_xmit(net, DSC_RESP_MSG, src, self, 0, &maddr, b);
256 }
257 
258 /* tipc_disc_add_dest - increment set of discovered nodes
259  */
tipc_disc_add_dest(struct tipc_discoverer * d)260 void tipc_disc_add_dest(struct tipc_discoverer *d)
261 {
262 	spin_lock_bh(&d->lock);
263 	d->num_nodes++;
264 	spin_unlock_bh(&d->lock);
265 }
266 
267 /* tipc_disc_remove_dest - decrement set of discovered nodes
268  */
tipc_disc_remove_dest(struct tipc_discoverer * d)269 void tipc_disc_remove_dest(struct tipc_discoverer *d)
270 {
271 	int intv, num;
272 
273 	spin_lock_bh(&d->lock);
274 	d->num_nodes--;
275 	num = d->num_nodes;
276 	intv = d->timer_intv;
277 	if (!num && (intv == TIPC_DISC_INACTIVE || intv > TIPC_DISC_FAST))  {
278 		d->timer_intv = TIPC_DISC_INIT;
279 		mod_timer(&d->timer, jiffies + d->timer_intv);
280 	}
281 	spin_unlock_bh(&d->lock);
282 }
283 
284 /* tipc_disc_timeout - send a periodic link setup request
285  * Called whenever a link setup request timer associated with a bearer expires.
286  * - Keep doubling time between sent request until limit is reached;
287  * - Hold at fast polling rate if we don't have any associated nodes
288  * - Otherwise hold at slow polling rate
289  */
tipc_disc_timeout(struct timer_list * t)290 static void tipc_disc_timeout(struct timer_list *t)
291 {
292 	struct tipc_discoverer *d = from_timer(d, t, timer);
293 	struct tipc_net *tn = tipc_net(d->net);
294 	struct tipc_media_addr maddr;
295 	struct sk_buff *skb = NULL;
296 	struct net *net = d->net;
297 	u32 bearer_id;
298 
299 	spin_lock_bh(&d->lock);
300 
301 	/* Stop searching if only desired node has been found */
302 	if (tipc_node(d->domain) && d->num_nodes) {
303 		d->timer_intv = TIPC_DISC_INACTIVE;
304 		goto exit;
305 	}
306 
307 	/* Did we just leave trial period ? */
308 	if (!time_before(jiffies, tn->addr_trial_end) && !tipc_own_addr(net)) {
309 		mod_timer(&d->timer, jiffies + TIPC_DISC_INIT);
310 		spin_unlock_bh(&d->lock);
311 		schedule_work(&tn->work);
312 		return;
313 	}
314 
315 	/* Adjust timeout interval according to discovery phase */
316 	if (time_before(jiffies, tn->addr_trial_end)) {
317 		d->timer_intv = TIPC_DISC_INIT;
318 	} else {
319 		d->timer_intv *= 2;
320 		if (d->num_nodes && d->timer_intv > TIPC_DISC_SLOW)
321 			d->timer_intv = TIPC_DISC_SLOW;
322 		else if (!d->num_nodes && d->timer_intv > TIPC_DISC_FAST)
323 			d->timer_intv = TIPC_DISC_FAST;
324 		msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
325 		msg_set_prevnode(buf_msg(d->skb), tn->trial_addr);
326 	}
327 
328 	mod_timer(&d->timer, jiffies + d->timer_intv);
329 	memcpy(&maddr, &d->dest, sizeof(maddr));
330 	skb = skb_clone(d->skb, GFP_ATOMIC);
331 	bearer_id = d->bearer_id;
332 exit:
333 	spin_unlock_bh(&d->lock);
334 	if (skb)
335 		tipc_bearer_xmit_skb(net, bearer_id, skb, &maddr);
336 }
337 
338 /**
339  * tipc_disc_create - create object to send periodic link setup requests
340  * @net: the applicable net namespace
341  * @b: ptr to bearer issuing requests
342  * @dest: destination address for request messages
343  * @skb: pointer to created frame
344  *
345  * Return: 0 if successful, otherwise -errno.
346  */
tipc_disc_create(struct net * net,struct tipc_bearer * b,struct tipc_media_addr * dest,struct sk_buff ** skb)347 int tipc_disc_create(struct net *net, struct tipc_bearer *b,
348 		     struct tipc_media_addr *dest, struct sk_buff **skb)
349 {
350 	struct tipc_net *tn = tipc_net(net);
351 	struct tipc_discoverer *d;
352 
353 	d = kmalloc(sizeof(*d), GFP_ATOMIC);
354 	if (!d)
355 		return -ENOMEM;
356 	d->skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
357 	if (!d->skb) {
358 		kfree(d);
359 		return -ENOMEM;
360 	}
361 	tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
362 
363 	/* Do we need an address trial period first ? */
364 	if (!tipc_own_addr(net)) {
365 		tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
366 		msg_set_type(buf_msg(d->skb), DSC_TRIAL_MSG);
367 	}
368 	memcpy(&d->dest, dest, sizeof(*dest));
369 	d->net = net;
370 	d->bearer_id = b->identity;
371 	d->domain = b->domain;
372 	d->num_nodes = 0;
373 	d->timer_intv = TIPC_DISC_INIT;
374 	spin_lock_init(&d->lock);
375 	timer_setup(&d->timer, tipc_disc_timeout, 0);
376 	mod_timer(&d->timer, jiffies + d->timer_intv);
377 	b->disc = d;
378 	*skb = skb_clone(d->skb, GFP_ATOMIC);
379 	return 0;
380 }
381 
382 /**
383  * tipc_disc_delete - destroy object sending periodic link setup requests
384  * @d: ptr to link dest structure
385  */
tipc_disc_delete(struct tipc_discoverer * d)386 void tipc_disc_delete(struct tipc_discoverer *d)
387 {
388 	del_timer_sync(&d->timer);
389 	kfree_skb(d->skb);
390 	kfree(d);
391 }
392 
393 /**
394  * tipc_disc_reset - reset object to send periodic link setup requests
395  * @net: the applicable net namespace
396  * @b: ptr to bearer issuing requests
397  */
tipc_disc_reset(struct net * net,struct tipc_bearer * b)398 void tipc_disc_reset(struct net *net, struct tipc_bearer *b)
399 {
400 	struct tipc_discoverer *d = b->disc;
401 	struct tipc_media_addr maddr;
402 	struct sk_buff *skb;
403 
404 	spin_lock_bh(&d->lock);
405 	tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
406 	d->net = net;
407 	d->bearer_id = b->identity;
408 	d->domain = b->domain;
409 	d->num_nodes = 0;
410 	d->timer_intv = TIPC_DISC_INIT;
411 	memcpy(&maddr, &d->dest, sizeof(maddr));
412 	mod_timer(&d->timer, jiffies + d->timer_intv);
413 	skb = skb_clone(d->skb, GFP_ATOMIC);
414 	spin_unlock_bh(&d->lock);
415 	if (skb)
416 		tipc_bearer_xmit_skb(net, b->identity, skb, &maddr);
417 }
418