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 */
62struct 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 */
81static 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(own_addr: tn->trial_addr, m: hdr, LINK_CONFIG, type: mtyp,
90 MAX_H_SIZE, destnode: dest_domain);
91 msg_set_size(m: hdr, MAX_H_SIZE + NODE_ID_LEN);
92 msg_set_non_seq(m: hdr, n: 1);
93 msg_set_node_sig(m: hdr, n: tn->random);
94 msg_set_node_capabilities(m: hdr, TIPC_NODE_CAPABILITIES);
95 msg_set_dest_domain(m: hdr, n: dest_domain);
96 msg_set_bc_netid(m: hdr, id: tn->net_id);
97 b->media->addr2msg(msg_media_addr(m: hdr), &b->addr);
98 msg_set_peer_net_hash(m: hdr, n: tipc_net_hash_mixes(net, tn_rand: tn->random));
99 msg_set_node_id(hdr, id: tipc_own_id(net));
100}
101
102static 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(m: hdr, n: sugg_addr);
116 msg_set_dest_domain(m: hdr, n: dst);
117 tipc_bearer_xmit_skb(net, bearer_id: b->identity, skb, dest: 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 */
126static 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(buf: media_addr_str, len: sizeof(media_addr_str),
132 a: 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 */
141static 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(m: buf_msg(skb: d->skb), a: sugg_addr);
165 tn->addr_trial_end = jiffies + msecs_to_jiffies(m: 1000);
166 return true;
167 }
168
169 /* Apply trial address if we just left trial period */
170 if (!trial && !self) {
171 schedule_work(work: &tn->work);
172 msg_set_prevnode(m: buf_msg(skb: d->skb), a: tn->trial_addr);
173 msg_set_type(m: buf_msg(skb: 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, id: peer_id, addr: src);
181 if (sugg_addr)
182 tipc_disc_msg_xmit(net, DSC_TRIAL_FAIL_MSG, dst: src,
183 src: 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 */
193void 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(m: hdr);
199 u16 caps = msg_node_capabilities(m: hdr);
200 bool legacy = tn->legacy_addr_format;
201 u32 sugg = msg_sugg_node_addr(m: hdr);
202 u32 signature = msg_node_sig(m: hdr);
203 u8 peer_id[NODE_ID_LEN] = {0,};
204 u32 dst = msg_dest_domain(m: hdr);
205 u32 net_id = msg_bc_netid(m: hdr);
206 struct tipc_media_addr maddr;
207 u32 src = msg_prevnode(m: hdr);
208 u32 mtyp = msg_type(m: 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(buf: peer_id, fmt: "%x", src);
224
225 err = b->media->msg2addr(b, &maddr, msg_media_addr(m: 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(p: &maddr, q: &b->addr, size: sizeof(maddr)))
233 return;
234 if (net_id != tn->net_id)
235 return;
236 if (tipc_disc_addr_trial_msg(d: b->disc, maddr: &maddr, b, dst,
237 src, sugg_addr: 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, addr: src)) {
243 disc_dupl_alert(b, node_addr: self, media_addr: &maddr);
244 return;
245 }
246 if (!tipc_in_scope(legacy_format: legacy, domain: dst, addr: self))
247 return;
248 if (!tipc_in_scope(legacy_format: legacy, domain: b->domain, addr: src))
249 return;
250 tipc_node_check_dest(net, onode: src, peer_id128: peer_id, bearer: b, capabilities: caps, signature, hash_mixes: pnet_hash,
251 maddr: &maddr, respond: &respond, dupl_addr: &dupl_addr);
252 if (dupl_addr)
253 disc_dupl_alert(b, node_addr: src, media_addr: &maddr);
254 if (!respond)
255 return;
256 if (mtyp != DSC_REQ_MSG)
257 return;
258 tipc_disc_msg_xmit(net, DSC_RESP_MSG, dst: src, src: self, sugg_addr: 0, maddr: &maddr, b);
259}
260
261/* tipc_disc_add_dest - increment set of discovered nodes
262 */
263void tipc_disc_add_dest(struct tipc_discoverer *d)
264{
265 spin_lock_bh(lock: &d->lock);
266 d->num_nodes++;
267 spin_unlock_bh(lock: &d->lock);
268}
269
270/* tipc_disc_remove_dest - decrement set of discovered nodes
271 */
272void tipc_disc_remove_dest(struct tipc_discoverer *d)
273{
274 int intv, num;
275
276 spin_lock_bh(lock: &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(timer: &d->timer, expires: jiffies + d->timer_intv);
283 }
284 spin_unlock_bh(lock: &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 */
293static 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(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(lock: &d->lock);
303
304 /* Stop searching if only desired node has been found */
305 if (tipc_node(addr: 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(timer: &d->timer, expires: jiffies + TIPC_DISC_INIT);
313 spin_unlock_bh(lock: &d->lock);
314 schedule_work(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(m: buf_msg(skb: d->skb), DSC_REQ_MSG);
328 msg_set_prevnode(m: buf_msg(skb: d->skb), a: tn->trial_addr);
329 }
330
331 mod_timer(timer: &d->timer, expires: jiffies + d->timer_intv);
332 memcpy(&maddr, &d->dest, sizeof(maddr));
333 skb = skb_clone(skb: d->skb, GFP_ATOMIC);
334 bearer_id = d->bearer_id;
335exit:
336 spin_unlock_bh(lock: &d->lock);
337 if (skb)
338 tipc_bearer_xmit_skb(net, bearer_id, skb, dest: &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 */
350int 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(size: 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(objp: d);
362 return -ENOMEM;
363 }
364 tipc_disc_init_msg(net, skb: 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(m: 1000);
369 msg_set_type(m: buf_msg(skb: 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(timer: &d->timer, expires: jiffies + d->timer_intv);
380 b->disc = d;
381 *skb = skb_clone(skb: 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 */
389void tipc_disc_delete(struct tipc_discoverer *d)
390{
391 timer_shutdown_sync(timer: &d->timer);
392 kfree_skb(skb: d->skb);
393 kfree(objp: 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 */
401void 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(lock: &d->lock);
408 tipc_disc_init_msg(net, skb: 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(timer: &d->timer, expires: jiffies + d->timer_intv);
416 skb = skb_clone(skb: d->skb, GFP_ATOMIC);
417 spin_unlock_bh(lock: &d->lock);
418 if (skb)
419 tipc_bearer_xmit_skb(net, bearer_id: b->identity, skb, dest: &maddr);
420}
421

source code of linux/net/tipc/discover.c