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1/*
2 * net/tipc/discover.c
3 *
4 * Copyright (c) 2003-2006, 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 "link.h"
39#include "discover.h"
40
41#define TIPC_LINK_REQ_INIT 125 /* min delay during bearer start up */
42#define TIPC_LINK_REQ_FAST 1000 /* max delay if bearer has no links */
43#define TIPC_LINK_REQ_SLOW 60000 /* max delay if bearer has links */
44#define TIPC_LINK_REQ_INACTIVE 0xffffffff /* indicates no timer in use */
45
46
47/**
48 * struct link_req - information about an ongoing link setup request
49 * @bearer: bearer issuing requests
50 * @dest: destination address for request messages
51 * @domain: network domain to which links can be established
52 * @num_nodes: number of nodes currently discovered (i.e. with an active link)
53 * @buf: request message to be (repeatedly) sent
54 * @timer: timer governing period between requests
55 * @timer_intv: current interval between requests (in ms)
56 */
57struct link_req {
58 struct tipc_bearer *bearer;
59 struct tipc_media_addr dest;
60 u32 domain;
61 int num_nodes;
62 struct sk_buff *buf;
63 struct timer_list timer;
64 unsigned int timer_intv;
65};
66
67/**
68 * tipc_disc_init_msg - initialize a link setup message
69 * @type: message type (request or response)
70 * @dest_domain: network domain of node(s) which should respond to message
71 * @b_ptr: ptr to bearer issuing message
72 */
73
74static struct sk_buff *tipc_disc_init_msg(u32 type,
75 u32 dest_domain,
76 struct tipc_bearer *b_ptr)
77{
78 struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE);
79 struct tipc_msg *msg;
80
81 if (buf) {
82 msg = buf_msg(buf);
83 tipc_msg_init(msg, LINK_CONFIG, type, INT_H_SIZE, dest_domain);
84 msg_set_non_seq(msg, 1);
85 msg_set_dest_domain(msg, dest_domain);
86 msg_set_bc_netid(msg, tipc_net_id);
87 msg_set_media_addr(msg, &b_ptr->addr);
88 }
89 return buf;
90}
91
92/**
93 * disc_dupl_alert - issue node address duplication alert
94 * @b_ptr: pointer to bearer detecting duplication
95 * @node_addr: duplicated node address
96 * @media_addr: media address advertised by duplicated node
97 */
98
99static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr,
100 struct tipc_media_addr *media_addr)
101{
102 char node_addr_str[16];
103 char media_addr_str[64];
104 struct print_buf pb;
105
106 tipc_addr_string_fill(node_addr_str, node_addr);
107 tipc_printbuf_init(&pb, media_addr_str, sizeof(media_addr_str));
108 tipc_media_addr_printf(&pb, media_addr);
109 tipc_printbuf_validate(&pb);
110 warn("Duplicate %s using %s seen on <%s>\n",
111 node_addr_str, media_addr_str, b_ptr->name);
112}
113
114/**
115 * tipc_disc_recv_msg - handle incoming link setup message (request or response)
116 * @buf: buffer containing message
117 * @b_ptr: bearer that message arrived on
118 */
119
120void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr)
121{
122 struct tipc_node *n_ptr;
123 struct link *link;
124 struct tipc_media_addr media_addr, *addr;
125 struct sk_buff *rbuf;
126 struct tipc_msg *msg = buf_msg(buf);
127 u32 dest = msg_dest_domain(msg);
128 u32 orig = msg_prevnode(msg);
129 u32 net_id = msg_bc_netid(msg);
130 u32 type = msg_type(msg);
131 int link_fully_up;
132
133 msg_get_media_addr(msg, &media_addr);
134 buf_discard(buf);
135
136 /* Validate discovery message from requesting node */
137 if (net_id != tipc_net_id)
138 return;
139 if (!tipc_addr_domain_valid(dest))
140 return;
141 if (!tipc_addr_node_valid(orig))
142 return;
143 if (orig == tipc_own_addr) {
144 if (memcmp(&media_addr, &b_ptr->addr, sizeof(media_addr)))
145 disc_dupl_alert(b_ptr, tipc_own_addr, &media_addr);
146 return;
147 }
148 if (!tipc_in_scope(dest, tipc_own_addr))
149 return;
150 if (!tipc_in_scope(b_ptr->link_req->domain, orig))
151 return;
152
153 /* Locate structure corresponding to requesting node */
154 n_ptr = tipc_node_find(orig);
155 if (!n_ptr) {
156 n_ptr = tipc_node_create(orig);
157 if (!n_ptr)
158 return;
159 }
160 tipc_node_lock(n_ptr);
161
162 /* Don't talk to neighbor during cleanup after last session */
163 if (n_ptr->cleanup_required) {
164 tipc_node_unlock(n_ptr);
165 return;
166 }
167
168 link = n_ptr->links[b_ptr->identity];
169
170 /* Create a link endpoint for this bearer, if necessary */
171 if (!link) {
172 link = tipc_link_create(n_ptr, b_ptr, &media_addr);
173 if (!link) {
174 tipc_node_unlock(n_ptr);
175 return;
176 }
177 }
178
179 /*
180 * Ensure requesting node's media address is correct
181 *
182 * If media address doesn't match and the link is working, reject the
183 * request (must be from a duplicate node).
184 *
185 * If media address doesn't match and the link is not working, accept
186 * the new media address and reset the link to ensure it starts up
187 * cleanly.
188 */
189 addr = &link->media_addr;
190 if (memcmp(addr, &media_addr, sizeof(*addr))) {
191 if (tipc_link_is_up(link) || (!link->started)) {
192 disc_dupl_alert(b_ptr, orig, &media_addr);
193 tipc_node_unlock(n_ptr);
194 return;
195 }
196 warn("Resetting link <%s>, peer interface address changed\n",
197 link->name);
198 memcpy(addr, &media_addr, sizeof(*addr));
199 tipc_link_reset(link);
200 }
201
202 /* Accept discovery message & send response, if necessary */
203 link_fully_up = link_working_working(link);
204
205 if ((type == DSC_REQ_MSG) && !link_fully_up && !b_ptr->blocked) {
206 rbuf = tipc_disc_init_msg(DSC_RESP_MSG, orig, b_ptr);
207 if (rbuf) {
208 b_ptr->media->send_msg(rbuf, b_ptr, &media_addr);
209 buf_discard(rbuf);
210 }
211 }
212
213 tipc_node_unlock(n_ptr);
214}
215
216/**
217 * disc_update - update frequency of periodic link setup requests
218 * @req: ptr to link request structure
219 *
220 * Reinitiates discovery process if discovery object has no associated nodes
221 * and is either not currently searching or is searching at a slow rate
222 */
223
224static void disc_update(struct link_req *req)
225{
226 if (!req->num_nodes) {
227 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) ||
228 (req->timer_intv > TIPC_LINK_REQ_FAST)) {
229 req->timer_intv = TIPC_LINK_REQ_INIT;
230 k_start_timer(&req->timer, req->timer_intv);
231 }
232 }
233}
234
235/**
236 * tipc_disc_add_dest - increment set of discovered nodes
237 * @req: ptr to link request structure
238 */
239
240void tipc_disc_add_dest(struct link_req *req)
241{
242 req->num_nodes++;
243}
244
245/**
246 * tipc_disc_remove_dest - decrement set of discovered nodes
247 * @req: ptr to link request structure
248 */
249
250void tipc_disc_remove_dest(struct link_req *req)
251{
252 req->num_nodes--;
253 disc_update(req);
254}
255
256/**
257 * disc_send_msg - send link setup request message
258 * @req: ptr to link request structure
259 */
260
261static void disc_send_msg(struct link_req *req)
262{
263 if (!req->bearer->blocked)
264 tipc_bearer_send(req->bearer, req->buf, &req->dest);
265}
266
267/**
268 * disc_timeout - send a periodic link setup request
269 * @req: ptr to link request structure
270 *
271 * Called whenever a link setup request timer associated with a bearer expires.
272 */
273
274static void disc_timeout(struct link_req *req)
275{
276 int max_delay;
277
278 spin_lock_bh(&req->bearer->lock);
279
280 /* Stop searching if only desired node has been found */
281
282 if (tipc_node(req->domain) && req->num_nodes) {
283 req->timer_intv = TIPC_LINK_REQ_INACTIVE;
284 goto exit;
285 }
286
287 /*
288 * Send discovery message, then update discovery timer
289 *
290 * Keep doubling time between requests until limit is reached;
291 * hold at fast polling rate if don't have any associated nodes,
292 * otherwise hold at slow polling rate
293 */
294
295 disc_send_msg(req);
296
297 req->timer_intv *= 2;
298 if (req->num_nodes)
299 max_delay = TIPC_LINK_REQ_SLOW;
300 else
301 max_delay = TIPC_LINK_REQ_FAST;
302 if (req->timer_intv > max_delay)
303 req->timer_intv = max_delay;
304
305 k_start_timer(&req->timer, req->timer_intv);
306exit:
307 spin_unlock_bh(&req->bearer->lock);
308}
309
310/**
311 * tipc_disc_create - create object to send periodic link setup requests
312 * @b_ptr: ptr to bearer issuing requests
313 * @dest: destination address for request messages
314 * @dest_domain: network domain to which links can be established
315 *
316 * Returns 0 if successful, otherwise -errno.
317 */
318
319int tipc_disc_create(struct tipc_bearer *b_ptr,
320 struct tipc_media_addr *dest, u32 dest_domain)
321{
322 struct link_req *req;
323
324 req = kmalloc(sizeof(*req), GFP_ATOMIC);
325 if (!req)
326 return -ENOMEM;
327
328 req->buf = tipc_disc_init_msg(DSC_REQ_MSG, dest_domain, b_ptr);
329 if (!req->buf) {
330 kfree(req);
331 return -ENOMSG;
332 }
333
334 memcpy(&req->dest, dest, sizeof(*dest));
335 req->bearer = b_ptr;
336 req->domain = dest_domain;
337 req->num_nodes = 0;
338 req->timer_intv = TIPC_LINK_REQ_INIT;
339 k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req);
340 k_start_timer(&req->timer, req->timer_intv);
341 b_ptr->link_req = req;
342 disc_send_msg(req);
343 return 0;
344}
345
346/**
347 * tipc_disc_delete - destroy object sending periodic link setup requests
348 * @req: ptr to link request structure
349 */
350
351void tipc_disc_delete(struct link_req *req)
352{
353 k_cancel_timer(&req->timer);
354 k_term_timer(&req->timer);
355 buf_discard(req->buf);
356 kfree(req);
357}
358
1/*
2 * net/tipc/discover.c
3 *
4 * Copyright (c) 2003-2006, 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 "link.h"
39#include "discover.h"
40
41#define TIPC_LINK_REQ_INIT 125 /* min delay during bearer start up */
42#define TIPC_LINK_REQ_FAST 1000 /* max delay if bearer has no links */
43#define TIPC_LINK_REQ_SLOW 60000 /* max delay if bearer has links */
44#define TIPC_LINK_REQ_INACTIVE 0xffffffff /* indicates no timer in use */
45
46
47/**
48 * struct tipc_link_req - information about an ongoing link setup request
49 * @bearer: bearer issuing requests
50 * @dest: destination address for request messages
51 * @domain: network domain to which links can be established
52 * @num_nodes: number of nodes currently discovered (i.e. with an active link)
53 * @buf: request message to be (repeatedly) sent
54 * @timer: timer governing period between requests
55 * @timer_intv: current interval between requests (in ms)
56 */
57struct tipc_link_req {
58 struct tipc_bearer *bearer;
59 struct tipc_media_addr dest;
60 u32 domain;
61 int num_nodes;
62 struct sk_buff *buf;
63 struct timer_list timer;
64 unsigned int timer_intv;
65};
66
67/**
68 * tipc_disc_init_msg - initialize a link setup message
69 * @type: message type (request or response)
70 * @dest_domain: network domain of node(s) which should respond to message
71 * @b_ptr: ptr to bearer issuing message
72 */
73static struct sk_buff *tipc_disc_init_msg(u32 type,
74 u32 dest_domain,
75 struct tipc_bearer *b_ptr)
76{
77 struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE);
78 struct tipc_msg *msg;
79
80 if (buf) {
81 msg = buf_msg(buf);
82 tipc_msg_init(msg, LINK_CONFIG, type, INT_H_SIZE, dest_domain);
83 msg_set_non_seq(msg, 1);
84 msg_set_node_sig(msg, tipc_random);
85 msg_set_dest_domain(msg, dest_domain);
86 msg_set_bc_netid(msg, tipc_net_id);
87 b_ptr->media->addr2msg(&b_ptr->addr, msg_media_addr(msg));
88 }
89 return buf;
90}
91
92/**
93 * disc_dupl_alert - issue node address duplication alert
94 * @b_ptr: pointer to bearer detecting duplication
95 * @node_addr: duplicated node address
96 * @media_addr: media address advertised by duplicated node
97 */
98static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr,
99 struct tipc_media_addr *media_addr)
100{
101 char node_addr_str[16];
102 char media_addr_str[64];
103 struct print_buf pb;
104
105 tipc_addr_string_fill(node_addr_str, node_addr);
106 tipc_printbuf_init(&pb, media_addr_str, sizeof(media_addr_str));
107 tipc_media_addr_printf(&pb, media_addr);
108 tipc_printbuf_validate(&pb);
109 warn("Duplicate %s using %s seen on <%s>\n",
110 node_addr_str, media_addr_str, b_ptr->name);
111}
112
113/**
114 * tipc_disc_recv_msg - handle incoming link setup message (request or response)
115 * @buf: buffer containing message
116 * @b_ptr: bearer that message arrived on
117 */
118void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr)
119{
120 struct tipc_node *n_ptr;
121 struct tipc_link *link;
122 struct tipc_media_addr media_addr;
123 struct sk_buff *rbuf;
124 struct tipc_msg *msg = buf_msg(buf);
125 u32 dest = msg_dest_domain(msg);
126 u32 orig = msg_prevnode(msg);
127 u32 net_id = msg_bc_netid(msg);
128 u32 type = msg_type(msg);
129 u32 signature = msg_node_sig(msg);
130 int addr_mismatch;
131 int link_fully_up;
132
133 media_addr.broadcast = 1;
134 b_ptr->media->msg2addr(&media_addr, msg_media_addr(msg));
135 kfree_skb(buf);
136
137 /* Ensure message from node is valid and communication is permitted */
138 if (net_id != tipc_net_id)
139 return;
140 if (media_addr.broadcast)
141 return;
142 if (!tipc_addr_domain_valid(dest))
143 return;
144 if (!tipc_addr_node_valid(orig))
145 return;
146 if (orig == tipc_own_addr) {
147 if (memcmp(&media_addr, &b_ptr->addr, sizeof(media_addr)))
148 disc_dupl_alert(b_ptr, tipc_own_addr, &media_addr);
149 return;
150 }
151 if (!tipc_in_scope(dest, tipc_own_addr))
152 return;
153 if (!tipc_in_scope(b_ptr->link_req->domain, orig))
154 return;
155
156 /* Locate structure corresponding to requesting node */
157 n_ptr = tipc_node_find(orig);
158 if (!n_ptr) {
159 n_ptr = tipc_node_create(orig);
160 if (!n_ptr)
161 return;
162 }
163 tipc_node_lock(n_ptr);
164
165 /* Prepare to validate requesting node's signature and media address */
166 link = n_ptr->links[b_ptr->identity];
167 addr_mismatch = (link != NULL) &&
168 memcmp(&link->media_addr, &media_addr, sizeof(media_addr));
169
170 /*
171 * Ensure discovery message's signature is correct
172 *
173 * If signature is incorrect and there is no working link to the node,
174 * accept the new signature but invalidate all existing links to the
175 * node so they won't re-activate without a new discovery message.
176 *
177 * If signature is incorrect and the requested link to the node is
178 * working, accept the new signature. (This is an instance of delayed
179 * rediscovery, where a link endpoint was able to re-establish contact
180 * with its peer endpoint on a node that rebooted before receiving a
181 * discovery message from that node.)
182 *
183 * If signature is incorrect and there is a working link to the node
184 * that is not the requested link, reject the request (must be from
185 * a duplicate node).
186 */
187 if (signature != n_ptr->signature) {
188 if (n_ptr->working_links == 0) {
189 struct tipc_link *curr_link;
190 int i;
191
192 for (i = 0; i < MAX_BEARERS; i++) {
193 curr_link = n_ptr->links[i];
194 if (curr_link) {
195 memset(&curr_link->media_addr, 0,
196 sizeof(media_addr));
197 tipc_link_reset(curr_link);
198 }
199 }
200 addr_mismatch = (link != NULL);
201 } else if (tipc_link_is_up(link) && !addr_mismatch) {
202 /* delayed rediscovery */
203 } else {
204 disc_dupl_alert(b_ptr, orig, &media_addr);
205 tipc_node_unlock(n_ptr);
206 return;
207 }
208 n_ptr->signature = signature;
209 }
210
211 /*
212 * Ensure requesting node's media address is correct
213 *
214 * If media address doesn't match and the link is working, reject the
215 * request (must be from a duplicate node).
216 *
217 * If media address doesn't match and the link is not working, accept
218 * the new media address and reset the link to ensure it starts up
219 * cleanly.
220 */
221 if (addr_mismatch) {
222 if (tipc_link_is_up(link)) {
223 disc_dupl_alert(b_ptr, orig, &media_addr);
224 tipc_node_unlock(n_ptr);
225 return;
226 } else {
227 memcpy(&link->media_addr, &media_addr,
228 sizeof(media_addr));
229 tipc_link_reset(link);
230 }
231 }
232
233 /* Create a link endpoint for this bearer, if necessary */
234 if (!link) {
235 link = tipc_link_create(n_ptr, b_ptr, &media_addr);
236 if (!link) {
237 tipc_node_unlock(n_ptr);
238 return;
239 }
240 }
241
242 /* Accept discovery message & send response, if necessary */
243 link_fully_up = link_working_working(link);
244
245 if ((type == DSC_REQ_MSG) && !link_fully_up && !b_ptr->blocked) {
246 rbuf = tipc_disc_init_msg(DSC_RESP_MSG, orig, b_ptr);
247 if (rbuf) {
248 b_ptr->media->send_msg(rbuf, b_ptr, &media_addr);
249 kfree_skb(rbuf);
250 }
251 }
252
253 tipc_node_unlock(n_ptr);
254}
255
256/**
257 * disc_update - update frequency of periodic link setup requests
258 * @req: ptr to link request structure
259 *
260 * Reinitiates discovery process if discovery object has no associated nodes
261 * and is either not currently searching or is searching at a slow rate
262 */
263static void disc_update(struct tipc_link_req *req)
264{
265 if (!req->num_nodes) {
266 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) ||
267 (req->timer_intv > TIPC_LINK_REQ_FAST)) {
268 req->timer_intv = TIPC_LINK_REQ_INIT;
269 k_start_timer(&req->timer, req->timer_intv);
270 }
271 }
272}
273
274/**
275 * tipc_disc_add_dest - increment set of discovered nodes
276 * @req: ptr to link request structure
277 */
278void tipc_disc_add_dest(struct tipc_link_req *req)
279{
280 req->num_nodes++;
281}
282
283/**
284 * tipc_disc_remove_dest - decrement set of discovered nodes
285 * @req: ptr to link request structure
286 */
287void tipc_disc_remove_dest(struct tipc_link_req *req)
288{
289 req->num_nodes--;
290 disc_update(req);
291}
292
293/**
294 * disc_send_msg - send link setup request message
295 * @req: ptr to link request structure
296 */
297static void disc_send_msg(struct tipc_link_req *req)
298{
299 if (!req->bearer->blocked)
300 tipc_bearer_send(req->bearer, req->buf, &req->dest);
301}
302
303/**
304 * disc_timeout - send a periodic link setup request
305 * @req: ptr to link request structure
306 *
307 * Called whenever a link setup request timer associated with a bearer expires.
308 */
309static void disc_timeout(struct tipc_link_req *req)
310{
311 int max_delay;
312
313 spin_lock_bh(&req->bearer->lock);
314
315 /* Stop searching if only desired node has been found */
316 if (tipc_node(req->domain) && req->num_nodes) {
317 req->timer_intv = TIPC_LINK_REQ_INACTIVE;
318 goto exit;
319 }
320
321 /*
322 * Send discovery message, then update discovery timer
323 *
324 * Keep doubling time between requests until limit is reached;
325 * hold at fast polling rate if don't have any associated nodes,
326 * otherwise hold at slow polling rate
327 */
328 disc_send_msg(req);
329
330 req->timer_intv *= 2;
331 if (req->num_nodes)
332 max_delay = TIPC_LINK_REQ_SLOW;
333 else
334 max_delay = TIPC_LINK_REQ_FAST;
335 if (req->timer_intv > max_delay)
336 req->timer_intv = max_delay;
337
338 k_start_timer(&req->timer, req->timer_intv);
339exit:
340 spin_unlock_bh(&req->bearer->lock);
341}
342
343/**
344 * tipc_disc_create - create object to send periodic link setup requests
345 * @b_ptr: ptr to bearer issuing requests
346 * @dest: destination address for request messages
347 * @dest_domain: network domain to which links can be established
348 *
349 * Returns 0 if successful, otherwise -errno.
350 */
351int tipc_disc_create(struct tipc_bearer *b_ptr,
352 struct tipc_media_addr *dest, u32 dest_domain)
353{
354 struct tipc_link_req *req;
355
356 req = kmalloc(sizeof(*req), GFP_ATOMIC);
357 if (!req)
358 return -ENOMEM;
359
360 req->buf = tipc_disc_init_msg(DSC_REQ_MSG, dest_domain, b_ptr);
361 if (!req->buf) {
362 kfree(req);
363 return -ENOMSG;
364 }
365
366 memcpy(&req->dest, dest, sizeof(*dest));
367 req->bearer = b_ptr;
368 req->domain = dest_domain;
369 req->num_nodes = 0;
370 req->timer_intv = TIPC_LINK_REQ_INIT;
371 k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req);
372 k_start_timer(&req->timer, req->timer_intv);
373 b_ptr->link_req = req;
374 disc_send_msg(req);
375 return 0;
376}
377
378/**
379 * tipc_disc_delete - destroy object sending periodic link setup requests
380 * @req: ptr to link request structure
381 */
382void tipc_disc_delete(struct tipc_link_req *req)
383{
384 k_cancel_timer(&req->timer);
385 k_term_timer(&req->timer);
386 kfree_skb(req->buf);
387 kfree(req);
388}