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