Loading...
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 * @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}