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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 * @rcu: RCU head for deferred freeing
62 */
63struct tipc_discoverer {
64 u32 bearer_id;
65 struct tipc_media_addr dest;
66 struct net *net;
67 u32 domain;
68 int num_nodes;
69 spinlock_t lock;
70 struct sk_buff *skb;
71 struct timer_list timer;
72 unsigned long timer_intv;
73 struct rcu_head rcu;
74};
75
76/**
77 * tipc_disc_init_msg - initialize a link setup message
78 * @net: the applicable net namespace
79 * @skb: buffer containing message
80 * @mtyp: message type (request or response)
81 * @b: ptr to bearer issuing message
82 */
83static void tipc_disc_init_msg(struct net *net, struct sk_buff *skb,
84 u32 mtyp, struct tipc_bearer *b)
85{
86 struct tipc_net *tn = tipc_net(net);
87 u32 dest_domain = b->domain;
88 struct tipc_msg *hdr;
89
90 hdr = buf_msg(skb);
91 tipc_msg_init(tn->trial_addr, hdr, LINK_CONFIG, mtyp,
92 MAX_H_SIZE, dest_domain);
93 msg_set_size(hdr, MAX_H_SIZE + NODE_ID_LEN);
94 msg_set_non_seq(hdr, 1);
95 msg_set_node_sig(hdr, tn->random);
96 msg_set_node_capabilities(hdr, TIPC_NODE_CAPABILITIES);
97 msg_set_dest_domain(hdr, dest_domain);
98 msg_set_bc_netid(hdr, tn->net_id);
99 b->media->addr2msg(msg_media_addr(hdr), &b->addr);
100 msg_set_peer_net_hash(hdr, tipc_net_hash_mixes(net, tn->random));
101 msg_set_node_id(hdr, tipc_own_id(net));
102}
103
104static void tipc_disc_msg_xmit(struct net *net, u32 mtyp, u32 dst,
105 u32 src, u32 sugg_addr,
106 struct tipc_media_addr *maddr,
107 struct tipc_bearer *b)
108{
109 struct tipc_msg *hdr;
110 struct sk_buff *skb;
111
112 skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
113 if (!skb)
114 return;
115 hdr = buf_msg(skb);
116 tipc_disc_init_msg(net, skb, mtyp, b);
117 msg_set_sugg_node_addr(hdr, sugg_addr);
118 msg_set_dest_domain(hdr, dst);
119 tipc_bearer_xmit_skb(net, b->identity, skb, maddr);
120}
121
122/**
123 * disc_dupl_alert - issue node address duplication alert
124 * @b: pointer to bearer detecting duplication
125 * @node_addr: duplicated node address
126 * @media_addr: media address advertised by duplicated node
127 */
128static void disc_dupl_alert(struct tipc_bearer *b, u32 node_addr,
129 struct tipc_media_addr *media_addr)
130{
131 char media_addr_str[64];
132
133 tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str),
134 media_addr);
135 pr_warn("Duplicate %x using %s seen on <%s>\n", node_addr,
136 media_addr_str, b->name);
137}
138
139/* tipc_disc_addr_trial(): - handle an address uniqueness trial from peer
140 * Returns true if message should be dropped by caller, i.e., if it is a
141 * trial message or we are inside trial period. Otherwise false.
142 */
143static bool tipc_disc_addr_trial_msg(struct tipc_discoverer *d,
144 struct tipc_media_addr *maddr,
145 struct tipc_bearer *b,
146 u32 dst, u32 src,
147 u32 sugg_addr,
148 u8 *peer_id,
149 int mtyp)
150{
151 struct net *net = d->net;
152 struct tipc_net *tn = tipc_net(net);
153 u32 self = tipc_own_addr(net);
154 bool trial = time_before(jiffies, tn->addr_trial_end) && !self;
155
156 if (mtyp == DSC_TRIAL_FAIL_MSG) {
157 if (!trial)
158 return true;
159
160 /* Ignore if somebody else already gave new suggestion */
161 if (dst != tn->trial_addr)
162 return true;
163
164 /* Otherwise update trial address and restart trial period */
165 tn->trial_addr = sugg_addr;
166 msg_set_prevnode(buf_msg(d->skb), sugg_addr);
167 tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
168 return true;
169 }
170
171 /* Apply trial address if we just left trial period */
172 if (!trial && !self) {
173 schedule_work(&tn->work);
174 msg_set_prevnode(buf_msg(d->skb), tn->trial_addr);
175 msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
176 }
177
178 /* Accept regular link requests/responses only after trial period */
179 if (mtyp != DSC_TRIAL_MSG)
180 return trial;
181
182 sugg_addr = tipc_node_try_addr(net, peer_id, src);
183 if (sugg_addr)
184 tipc_disc_msg_xmit(net, DSC_TRIAL_FAIL_MSG, src,
185 self, sugg_addr, maddr, b);
186 return true;
187}
188
189/**
190 * tipc_disc_rcv - handle incoming discovery message (request or response)
191 * @net: applicable net namespace
192 * @skb: buffer containing message
193 * @b: bearer that message arrived on
194 */
195void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
196 struct tipc_bearer *b)
197{
198 struct tipc_net *tn = tipc_net(net);
199 struct tipc_msg *hdr = buf_msg(skb);
200 u32 pnet_hash = msg_peer_net_hash(hdr);
201 u16 caps = msg_node_capabilities(hdr);
202 bool legacy = tn->legacy_addr_format;
203 u32 sugg = msg_sugg_node_addr(hdr);
204 u32 signature = msg_node_sig(hdr);
205 u8 peer_id[NODE_ID_LEN] = {0,};
206 u32 dst = msg_dest_domain(hdr);
207 u32 net_id = msg_bc_netid(hdr);
208 struct tipc_media_addr maddr;
209 u32 src = msg_prevnode(hdr);
210 u32 mtyp = msg_type(hdr);
211 bool dupl_addr = false;
212 bool respond = false;
213 u32 self;
214 int err;
215
216 if (skb_linearize(skb)) {
217 kfree_skb(skb);
218 return;
219 }
220 hdr = buf_msg(skb);
221
222 if (caps & TIPC_NODE_ID128)
223 memcpy(peer_id, msg_node_id(hdr), NODE_ID_LEN);
224 else
225 sprintf(peer_id, "%x", src);
226
227 err = b->media->msg2addr(b, &maddr, msg_media_addr(hdr));
228 kfree_skb(skb);
229 if (err || maddr.broadcast) {
230 pr_warn_ratelimited("Rcv corrupt discovery message\n");
231 return;
232 }
233 /* Ignore discovery messages from own node */
234 if (!memcmp(&maddr, &b->addr, sizeof(maddr)))
235 return;
236 if (net_id != tn->net_id)
237 return;
238 if (tipc_disc_addr_trial_msg(b->disc, &maddr, b, dst,
239 src, sugg, peer_id, mtyp))
240 return;
241 self = tipc_own_addr(net);
242
243 /* Message from somebody using this node's address */
244 if (in_own_node(net, src)) {
245 disc_dupl_alert(b, self, &maddr);
246 return;
247 }
248 if (!tipc_in_scope(legacy, dst, self))
249 return;
250 if (!tipc_in_scope(legacy, b->domain, src))
251 return;
252 tipc_node_check_dest(net, src, peer_id, b, caps, signature, pnet_hash,
253 &maddr, &respond, &dupl_addr);
254 if (dupl_addr)
255 disc_dupl_alert(b, src, &maddr);
256 if (!respond)
257 return;
258 if (mtyp != DSC_REQ_MSG)
259 return;
260 tipc_disc_msg_xmit(net, DSC_RESP_MSG, src, self, 0, &maddr, b);
261}
262
263/* tipc_disc_add_dest - increment set of discovered nodes
264 */
265void tipc_disc_add_dest(struct tipc_discoverer *d)
266{
267 spin_lock_bh(&d->lock);
268 d->num_nodes++;
269 spin_unlock_bh(&d->lock);
270}
271
272/* tipc_disc_remove_dest - decrement set of discovered nodes
273 */
274void tipc_disc_remove_dest(struct tipc_discoverer *d)
275{
276 int intv, num;
277
278 spin_lock_bh(&d->lock);
279 d->num_nodes--;
280 num = d->num_nodes;
281 intv = d->timer_intv;
282 if (!num && (intv == TIPC_DISC_INACTIVE || intv > TIPC_DISC_FAST)) {
283 d->timer_intv = TIPC_DISC_INIT;
284 mod_timer(&d->timer, jiffies + d->timer_intv);
285 }
286 spin_unlock_bh(&d->lock);
287}
288
289/* tipc_disc_timeout - send a periodic link setup request
290 * Called whenever a link setup request timer associated with a bearer expires.
291 * - Keep doubling time between sent request until limit is reached;
292 * - Hold at fast polling rate if we don't have any associated nodes
293 * - Otherwise hold at slow polling rate
294 */
295static void tipc_disc_timeout(struct timer_list *t)
296{
297 struct tipc_discoverer *d = timer_container_of(d, t, timer);
298 struct tipc_net *tn = tipc_net(d->net);
299 struct tipc_media_addr maddr;
300 struct sk_buff *skb = NULL;
301 struct net *net = d->net;
302 u32 bearer_id;
303
304 spin_lock_bh(&d->lock);
305
306 /* Stop searching if only desired node has been found */
307 if (tipc_node(d->domain) && d->num_nodes) {
308 d->timer_intv = TIPC_DISC_INACTIVE;
309 goto exit;
310 }
311
312 /* Did we just leave trial period ? */
313 if (!time_before(jiffies, tn->addr_trial_end) && !tipc_own_addr(net)) {
314 mod_timer(&d->timer, jiffies + TIPC_DISC_INIT);
315 spin_unlock_bh(&d->lock);
316 schedule_work(&tn->work);
317 return;
318 }
319
320 /* Adjust timeout interval according to discovery phase */
321 if (time_before(jiffies, tn->addr_trial_end)) {
322 d->timer_intv = TIPC_DISC_INIT;
323 } else {
324 d->timer_intv *= 2;
325 if (d->num_nodes && d->timer_intv > TIPC_DISC_SLOW)
326 d->timer_intv = TIPC_DISC_SLOW;
327 else if (!d->num_nodes && d->timer_intv > TIPC_DISC_FAST)
328 d->timer_intv = TIPC_DISC_FAST;
329 msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
330 msg_set_prevnode(buf_msg(d->skb), tn->trial_addr);
331 }
332
333 mod_timer(&d->timer, jiffies + d->timer_intv);
334 memcpy(&maddr, &d->dest, sizeof(maddr));
335 skb = skb_clone(d->skb, GFP_ATOMIC);
336 bearer_id = d->bearer_id;
337exit:
338 spin_unlock_bh(&d->lock);
339 if (skb)
340 tipc_bearer_xmit_skb(net, bearer_id, skb, &maddr);
341}
342
343/**
344 * tipc_disc_create - create object to send periodic link setup requests
345 * @net: the applicable net namespace
346 * @b: ptr to bearer issuing requests
347 * @dest: destination address for request messages
348 * @skb: pointer to created frame
349 *
350 * Return: 0 if successful, otherwise -errno.
351 */
352int tipc_disc_create(struct net *net, struct tipc_bearer *b,
353 struct tipc_media_addr *dest, struct sk_buff **skb)
354{
355 struct tipc_net *tn = tipc_net(net);
356 struct tipc_discoverer *d;
357
358 d = kmalloc_obj(*d, GFP_ATOMIC);
359 if (!d)
360 return -ENOMEM;
361 d->skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
362 if (!d->skb) {
363 kfree(d);
364 return -ENOMEM;
365 }
366 tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
367
368 /* Do we need an address trial period first ? */
369 if (!tipc_own_addr(net)) {
370 tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
371 msg_set_type(buf_msg(d->skb), DSC_TRIAL_MSG);
372 }
373 memcpy(&d->dest, dest, sizeof(*dest));
374 d->net = net;
375 d->bearer_id = b->identity;
376 d->domain = b->domain;
377 d->num_nodes = 0;
378 d->timer_intv = TIPC_DISC_INIT;
379 spin_lock_init(&d->lock);
380 timer_setup(&d->timer, tipc_disc_timeout, 0);
381 mod_timer(&d->timer, jiffies + d->timer_intv);
382 b->disc = d;
383 *skb = skb_clone(d->skb, GFP_ATOMIC);
384 return 0;
385}
386
387static void tipc_disc_free_rcu(struct rcu_head *rp)
388{
389 struct tipc_discoverer *d = container_of(rp, struct tipc_discoverer,
390 rcu);
391
392 kfree_skb(d->skb);
393 kfree(d);
394}
395
396/**
397 * tipc_disc_delete - destroy object sending periodic link setup requests
398 * @d: ptr to link dest structure
399 */
400void tipc_disc_delete(struct tipc_discoverer *d)
401{
402 timer_shutdown_sync(&d->timer);
403 call_rcu(&d->rcu, tipc_disc_free_rcu);
404}
405
406/**
407 * tipc_disc_reset - reset object to send periodic link setup requests
408 * @net: the applicable net namespace
409 * @b: ptr to bearer issuing requests
410 */
411void tipc_disc_reset(struct net *net, struct tipc_bearer *b)
412{
413 struct tipc_discoverer *d = b->disc;
414 struct tipc_media_addr maddr;
415 struct sk_buff *skb;
416
417 spin_lock_bh(&d->lock);
418 tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
419 d->net = net;
420 d->bearer_id = b->identity;
421 d->domain = b->domain;
422 d->num_nodes = 0;
423 d->timer_intv = TIPC_DISC_INIT;
424 memcpy(&maddr, &d->dest, sizeof(maddr));
425 mod_timer(&d->timer, jiffies + d->timer_intv);
426 skb = skb_clone(d->skb, GFP_ATOMIC);
427 spin_unlock_bh(&d->lock);
428 if (skb)
429 tipc_bearer_xmit_skb(net, b->identity, skb, &maddr);
430}