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