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 */
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
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 */
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 */
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 u32 self = tipc_own_addr(net);
152 bool trial = time_before(jiffies, tn->addr_trial_end) && !self;
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 */
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 if (skb_linearize(skb)) {
215 kfree_skb(skb);
216 return;
217 }
218 hdr = buf_msg(skb);
219
220 if (caps & TIPC_NODE_ID128)
221 memcpy(peer_id, msg_node_id(hdr), NODE_ID_LEN);
222 else
223 sprintf(peer_id, "%x", src);
224
225 err = b->media->msg2addr(b, &maddr, msg_media_addr(hdr));
226 kfree_skb(skb);
227 if (err || maddr.broadcast) {
228 pr_warn_ratelimited("Rcv corrupt discovery message\n");
229 return;
230 }
231 /* Ignore discovery messages from own node */
232 if (!memcmp(&maddr, &b->addr, sizeof(maddr)))
233 return;
234 if (net_id != tn->net_id)
235 return;
236 if (tipc_disc_addr_trial_msg(b->disc, &maddr, b, dst,
237 src, sugg, peer_id, mtyp))
238 return;
239 self = tipc_own_addr(net);
240
241 /* Message from somebody using this node's address */
242 if (in_own_node(net, src)) {
243 disc_dupl_alert(b, self, &maddr);
244 return;
245 }
246 if (!tipc_in_scope(legacy, dst, self))
247 return;
248 if (!tipc_in_scope(legacy, b->domain, src))
249 return;
250 tipc_node_check_dest(net, src, peer_id, b, caps, signature, pnet_hash,
251 &maddr, &respond, &dupl_addr);
252 if (dupl_addr)
253 disc_dupl_alert(b, src, &maddr);
254 if (!respond)
255 return;
256 if (mtyp != DSC_REQ_MSG)
257 return;
258 tipc_disc_msg_xmit(net, DSC_RESP_MSG, src, self, 0, &maddr, b);
259 }
260
261 /* tipc_disc_add_dest - increment set of discovered nodes
262 */
263 void tipc_disc_add_dest(struct tipc_discoverer *d)
264 {
265 spin_lock_bh(&d->lock);
266 d->num_nodes++;
267 spin_unlock_bh(&d->lock);
268 }
269
270 /* tipc_disc_remove_dest - decrement set of discovered nodes
271 */
272 void tipc_disc_remove_dest(struct tipc_discoverer *d)
273 {
274 int intv, num;
275
276 spin_lock_bh(&d->lock);
277 d->num_nodes--;
278 num = d->num_nodes;
279 intv = d->timer_intv;
280 if (!num && (intv == TIPC_DISC_INACTIVE || intv > TIPC_DISC_FAST)) {
281 d->timer_intv = TIPC_DISC_INIT;
282 mod_timer(&d->timer, jiffies + d->timer_intv);
283 }
284 spin_unlock_bh(&d->lock);
285 }
286
287 /* tipc_disc_timeout - send a periodic link setup request
288 * Called whenever a link setup request timer associated with a bearer expires.
289 * - Keep doubling time between sent request until limit is reached;
290 * - Hold at fast polling rate if we don't have any associated nodes
291 * - Otherwise hold at slow polling rate
292 */
293 static void tipc_disc_timeout(struct timer_list *t)
294 {
295 struct tipc_discoverer *d = from_timer(d, t, timer);
296 struct tipc_net *tn = tipc_net(d->net);
297 struct tipc_media_addr maddr;
298 struct sk_buff *skb = NULL;
299 struct net *net = d->net;
300 u32 bearer_id;
301
302 spin_lock_bh(&d->lock);
303
304 /* Stop searching if only desired node has been found */
305 if (tipc_node(d->domain) && d->num_nodes) {
306 d->timer_intv = TIPC_DISC_INACTIVE;
307 goto exit;
308 }
309
310 /* Did we just leave trial period ? */
311 if (!time_before(jiffies, tn->addr_trial_end) && !tipc_own_addr(net)) {
312 mod_timer(&d->timer, jiffies + TIPC_DISC_INIT);
313 spin_unlock_bh(&d->lock);
314 schedule_work(&tn->work);
315 return;
316 }
317
318 /* Adjust timeout interval according to discovery phase */
319 if (time_before(jiffies, tn->addr_trial_end)) {
320 d->timer_intv = TIPC_DISC_INIT;
321 } else {
322 d->timer_intv *= 2;
323 if (d->num_nodes && d->timer_intv > TIPC_DISC_SLOW)
324 d->timer_intv = TIPC_DISC_SLOW;
325 else if (!d->num_nodes && d->timer_intv > TIPC_DISC_FAST)
326 d->timer_intv = TIPC_DISC_FAST;
327 msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
328 msg_set_prevnode(buf_msg(d->skb), tn->trial_addr);
329 }
330
331 mod_timer(&d->timer, jiffies + d->timer_intv);
332 memcpy(&maddr, &d->dest, sizeof(maddr));
333 skb = skb_clone(d->skb, GFP_ATOMIC);
334 bearer_id = d->bearer_id;
335 exit:
336 spin_unlock_bh(&d->lock);
337 if (skb)
338 tipc_bearer_xmit_skb(net, bearer_id, skb, &maddr);
339 }
340
341 /**
342 * tipc_disc_create - create object to send periodic link setup requests
343 * @net: the applicable net namespace
344 * @b: ptr to bearer issuing requests
345 * @dest: destination address for request messages
346 * @skb: pointer to created frame
347 *
348 * Return: 0 if successful, otherwise -errno.
349 */
350 int tipc_disc_create(struct net *net, struct tipc_bearer *b,
351 struct tipc_media_addr *dest, struct sk_buff **skb)
352 {
353 struct tipc_net *tn = tipc_net(net);
354 struct tipc_discoverer *d;
355
356 d = kmalloc(sizeof(*d), GFP_ATOMIC);
357 if (!d)
358 return -ENOMEM;
359 d->skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
360 if (!d->skb) {
361 kfree(d);
362 return -ENOMEM;
363 }
364 tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
365
366 /* Do we need an address trial period first ? */
367 if (!tipc_own_addr(net)) {
368 tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
369 msg_set_type(buf_msg(d->skb), DSC_TRIAL_MSG);
370 }
371 memcpy(&d->dest, dest, sizeof(*dest));
372 d->net = net;
373 d->bearer_id = b->identity;
374 d->domain = b->domain;
375 d->num_nodes = 0;
376 d->timer_intv = TIPC_DISC_INIT;
377 spin_lock_init(&d->lock);
378 timer_setup(&d->timer, tipc_disc_timeout, 0);
379 mod_timer(&d->timer, jiffies + d->timer_intv);
380 b->disc = d;
381 *skb = skb_clone(d->skb, GFP_ATOMIC);
382 return 0;
383 }
384
385 /**
386 * tipc_disc_delete - destroy object sending periodic link setup requests
387 * @d: ptr to link dest structure
388 */
389 void tipc_disc_delete(struct tipc_discoverer *d)
390 {
391 timer_shutdown_sync(&d->timer);
392 kfree_skb(d->skb);
393 kfree(d);
394 }
395
396 /**
397 * tipc_disc_reset - reset object to send periodic link setup requests
398 * @net: the applicable net namespace
399 * @b: ptr to bearer issuing requests
400 */
401 void tipc_disc_reset(struct net *net, struct tipc_bearer *b)
402 {
403 struct tipc_discoverer *d = b->disc;
404 struct tipc_media_addr maddr;
405 struct sk_buff *skb;
406
407 spin_lock_bh(&d->lock);
408 tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
409 d->net = net;
410 d->bearer_id = b->identity;
411 d->domain = b->domain;
412 d->num_nodes = 0;
413 d->timer_intv = TIPC_DISC_INIT;
414 memcpy(&maddr, &d->dest, sizeof(maddr));
415 mod_timer(&d->timer, jiffies + d->timer_intv);
416 skb = skb_clone(d->skb, GFP_ATOMIC);
417 spin_unlock_bh(&d->lock);
418 if (skb)
419 tipc_bearer_xmit_skb(net, b->identity, skb, &maddr);
420 }
421
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