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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 * @mtyp: 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_peer_net_hash(hdr, tipc_net_hash_mixes(net, tn->random));
98 msg_set_node_id(hdr, tipc_own_id(net));
99}
100
101static void tipc_disc_msg_xmit(struct net *net, u32 mtyp, u32 dst,
102 u32 src, u32 sugg_addr,
103 struct tipc_media_addr *maddr,
104 struct tipc_bearer *b)
105{
106 struct tipc_msg *hdr;
107 struct sk_buff *skb;
108
109 skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
110 if (!skb)
111 return;
112 hdr = buf_msg(skb);
113 tipc_disc_init_msg(net, skb, mtyp, b);
114 msg_set_sugg_node_addr(hdr, sugg_addr);
115 msg_set_dest_domain(hdr, dst);
116 tipc_bearer_xmit_skb(net, b->identity, skb, maddr);
117}
118
119/**
120 * disc_dupl_alert - issue node address duplication alert
121 * @b: pointer to bearer detecting duplication
122 * @node_addr: duplicated node address
123 * @media_addr: media address advertised by duplicated node
124 */
125static void disc_dupl_alert(struct tipc_bearer *b, u32 node_addr,
126 struct tipc_media_addr *media_addr)
127{
128 char media_addr_str[64];
129
130 tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str),
131 media_addr);
132 pr_warn("Duplicate %x using %s seen on <%s>\n", node_addr,
133 media_addr_str, b->name);
134}
135
136/* tipc_disc_addr_trial(): - handle an address uniqueness trial from peer
137 * Returns true if message should be dropped by caller, i.e., if it is a
138 * trial message or we are inside trial period. Otherwise false.
139 */
140static bool tipc_disc_addr_trial_msg(struct tipc_discoverer *d,
141 struct tipc_media_addr *maddr,
142 struct tipc_bearer *b,
143 u32 dst, u32 src,
144 u32 sugg_addr,
145 u8 *peer_id,
146 int mtyp)
147{
148 struct net *net = d->net;
149 struct tipc_net *tn = tipc_net(net);
150 bool trial = time_before(jiffies, tn->addr_trial_end);
151 u32 self = tipc_own_addr(net);
152
153 if (mtyp == DSC_TRIAL_FAIL_MSG) {
154 if (!trial)
155 return true;
156
157 /* Ignore if somebody else already gave new suggestion */
158 if (dst != tn->trial_addr)
159 return true;
160
161 /* Otherwise update trial address and restart trial period */
162 tn->trial_addr = sugg_addr;
163 msg_set_prevnode(buf_msg(d->skb), sugg_addr);
164 tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
165 return true;
166 }
167
168 /* Apply trial address if we just left trial period */
169 if (!trial && !self) {
170 tipc_sched_net_finalize(net, tn->trial_addr);
171 msg_set_prevnode(buf_msg(d->skb), tn->trial_addr);
172 msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
173 }
174
175 /* Accept regular link requests/responses only after trial period */
176 if (mtyp != DSC_TRIAL_MSG)
177 return trial;
178
179 sugg_addr = tipc_node_try_addr(net, peer_id, src);
180 if (sugg_addr)
181 tipc_disc_msg_xmit(net, DSC_TRIAL_FAIL_MSG, src,
182 self, sugg_addr, maddr, b);
183 return true;
184}
185
186/**
187 * tipc_disc_rcv - handle incoming discovery message (request or response)
188 * @net: applicable net namespace
189 * @skb: buffer containing message
190 * @b: bearer that message arrived on
191 */
192void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
193 struct tipc_bearer *b)
194{
195 struct tipc_net *tn = tipc_net(net);
196 struct tipc_msg *hdr = buf_msg(skb);
197 u32 pnet_hash = msg_peer_net_hash(hdr);
198 u16 caps = msg_node_capabilities(hdr);
199 bool legacy = tn->legacy_addr_format;
200 u32 sugg = msg_sugg_node_addr(hdr);
201 u32 signature = msg_node_sig(hdr);
202 u8 peer_id[NODE_ID_LEN] = {0,};
203 u32 dst = msg_dest_domain(hdr);
204 u32 net_id = msg_bc_netid(hdr);
205 struct tipc_media_addr maddr;
206 u32 src = msg_prevnode(hdr);
207 u32 mtyp = msg_type(hdr);
208 bool dupl_addr = false;
209 bool respond = false;
210 u32 self;
211 int err;
212
213 skb_linearize(skb);
214 hdr = buf_msg(skb);
215
216 if (caps & TIPC_NODE_ID128)
217 memcpy(peer_id, msg_node_id(hdr), NODE_ID_LEN);
218 else
219 sprintf(peer_id, "%x", src);
220
221 err = b->media->msg2addr(b, &maddr, msg_media_addr(hdr));
222 kfree_skb(skb);
223 if (err || maddr.broadcast) {
224 pr_warn_ratelimited("Rcv corrupt discovery message\n");
225 return;
226 }
227 /* Ignore discovery messages from own node */
228 if (!memcmp(&maddr, &b->addr, sizeof(maddr)))
229 return;
230 if (net_id != tn->net_id)
231 return;
232 if (tipc_disc_addr_trial_msg(b->disc, &maddr, b, dst,
233 src, sugg, peer_id, mtyp))
234 return;
235 self = tipc_own_addr(net);
236
237 /* Message from somebody using this node's address */
238 if (in_own_node(net, src)) {
239 disc_dupl_alert(b, self, &maddr);
240 return;
241 }
242 if (!tipc_in_scope(legacy, dst, self))
243 return;
244 if (!tipc_in_scope(legacy, b->domain, src))
245 return;
246 tipc_node_check_dest(net, src, peer_id, b, caps, signature, pnet_hash,
247 &maddr, &respond, &dupl_addr);
248 if (dupl_addr)
249 disc_dupl_alert(b, src, &maddr);
250 if (!respond)
251 return;
252 if (mtyp != DSC_REQ_MSG)
253 return;
254 tipc_disc_msg_xmit(net, DSC_RESP_MSG, src, self, 0, &maddr, b);
255}
256
257/* tipc_disc_add_dest - increment set of discovered nodes
258 */
259void tipc_disc_add_dest(struct tipc_discoverer *d)
260{
261 spin_lock_bh(&d->lock);
262 d->num_nodes++;
263 spin_unlock_bh(&d->lock);
264}
265
266/* tipc_disc_remove_dest - decrement set of discovered nodes
267 */
268void tipc_disc_remove_dest(struct tipc_discoverer *d)
269{
270 int intv, num;
271
272 spin_lock_bh(&d->lock);
273 d->num_nodes--;
274 num = d->num_nodes;
275 intv = d->timer_intv;
276 if (!num && (intv == TIPC_DISC_INACTIVE || intv > TIPC_DISC_FAST)) {
277 d->timer_intv = TIPC_DISC_INIT;
278 mod_timer(&d->timer, jiffies + d->timer_intv);
279 }
280 spin_unlock_bh(&d->lock);
281}
282
283/* tipc_disc_timeout - send a periodic link setup request
284 * Called whenever a link setup request timer associated with a bearer expires.
285 * - Keep doubling time between sent request until limit is reached;
286 * - Hold at fast polling rate if we don't have any associated nodes
287 * - Otherwise hold at slow polling rate
288 */
289static void tipc_disc_timeout(struct timer_list *t)
290{
291 struct tipc_discoverer *d = from_timer(d, t, timer);
292 struct tipc_net *tn = tipc_net(d->net);
293 struct tipc_media_addr maddr;
294 struct sk_buff *skb = NULL;
295 struct net *net = d->net;
296 u32 bearer_id;
297
298 spin_lock_bh(&d->lock);
299
300 /* Stop searching if only desired node has been found */
301 if (tipc_node(d->domain) && d->num_nodes) {
302 d->timer_intv = TIPC_DISC_INACTIVE;
303 goto exit;
304 }
305
306 /* Did we just leave trial period ? */
307 if (!time_before(jiffies, tn->addr_trial_end) && !tipc_own_addr(net)) {
308 mod_timer(&d->timer, jiffies + TIPC_DISC_INIT);
309 spin_unlock_bh(&d->lock);
310 tipc_sched_net_finalize(net, tn->trial_addr);
311 return;
312 }
313
314 /* Adjust timeout interval according to discovery phase */
315 if (time_before(jiffies, tn->addr_trial_end)) {
316 d->timer_intv = TIPC_DISC_INIT;
317 } else {
318 d->timer_intv *= 2;
319 if (d->num_nodes && d->timer_intv > TIPC_DISC_SLOW)
320 d->timer_intv = TIPC_DISC_SLOW;
321 else if (!d->num_nodes && d->timer_intv > TIPC_DISC_FAST)
322 d->timer_intv = TIPC_DISC_FAST;
323 msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
324 msg_set_prevnode(buf_msg(d->skb), tn->trial_addr);
325 }
326
327 mod_timer(&d->timer, jiffies + d->timer_intv);
328 memcpy(&maddr, &d->dest, sizeof(maddr));
329 skb = skb_clone(d->skb, GFP_ATOMIC);
330 bearer_id = d->bearer_id;
331exit:
332 spin_unlock_bh(&d->lock);
333 if (skb)
334 tipc_bearer_xmit_skb(net, bearer_id, skb, &maddr);
335}
336
337/**
338 * tipc_disc_create - create object to send periodic link setup requests
339 * @net: the applicable net namespace
340 * @b: ptr to bearer issuing requests
341 * @dest: destination address for request messages
342 * @skb: pointer to created frame
343 *
344 * Returns 0 if successful, otherwise -errno.
345 */
346int tipc_disc_create(struct net *net, struct tipc_bearer *b,
347 struct tipc_media_addr *dest, struct sk_buff **skb)
348{
349 struct tipc_net *tn = tipc_net(net);
350 struct tipc_discoverer *d;
351
352 d = kmalloc(sizeof(*d), GFP_ATOMIC);
353 if (!d)
354 return -ENOMEM;
355 d->skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
356 if (!d->skb) {
357 kfree(d);
358 return -ENOMEM;
359 }
360 tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
361
362 /* Do we need an address trial period first ? */
363 if (!tipc_own_addr(net)) {
364 tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
365 msg_set_type(buf_msg(d->skb), DSC_TRIAL_MSG);
366 }
367 memcpy(&d->dest, dest, sizeof(*dest));
368 d->net = net;
369 d->bearer_id = b->identity;
370 d->domain = b->domain;
371 d->num_nodes = 0;
372 d->timer_intv = TIPC_DISC_INIT;
373 spin_lock_init(&d->lock);
374 timer_setup(&d->timer, tipc_disc_timeout, 0);
375 mod_timer(&d->timer, jiffies + d->timer_intv);
376 b->disc = d;
377 *skb = skb_clone(d->skb, GFP_ATOMIC);
378 return 0;
379}
380
381/**
382 * tipc_disc_delete - destroy object sending periodic link setup requests
383 * @d: ptr to link duest structure
384 */
385void tipc_disc_delete(struct tipc_discoverer *d)
386{
387 del_timer_sync(&d->timer);
388 kfree_skb(d->skb);
389 kfree(d);
390}
391
392/**
393 * tipc_disc_reset - reset object to send periodic link setup requests
394 * @net: the applicable net namespace
395 * @b: ptr to bearer issuing requests
396 */
397void tipc_disc_reset(struct net *net, struct tipc_bearer *b)
398{
399 struct tipc_discoverer *d = b->disc;
400 struct tipc_media_addr maddr;
401 struct sk_buff *skb;
402
403 spin_lock_bh(&d->lock);
404 tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
405 d->net = net;
406 d->bearer_id = b->identity;
407 d->domain = b->domain;
408 d->num_nodes = 0;
409 d->timer_intv = TIPC_DISC_INIT;
410 memcpy(&maddr, &d->dest, sizeof(maddr));
411 mod_timer(&d->timer, jiffies + d->timer_intv);
412 skb = skb_clone(d->skb, GFP_ATOMIC);
413 spin_unlock_bh(&d->lock);
414 if (skb)
415 tipc_bearer_xmit_skb(net, b->identity, skb, &maddr);
416}
1/*
2 * net/tipc/discover.c
3 *
4 * Copyright (c) 2003-2006, 2014-2015, 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_LINK_REQ_INIT msecs_to_jiffies(125)
43/* max delay if bearer has no links */
44#define TIPC_LINK_REQ_FAST msecs_to_jiffies(1000)
45/* max delay if bearer has links */
46#define TIPC_LINK_REQ_SLOW msecs_to_jiffies(60000)
47/* indicates no timer in use */
48#define TIPC_LINK_REQ_INACTIVE 0xffffffff
49
50/**
51 * struct tipc_link_req - 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 * @buf: 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_link_req {
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 *buf;
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 *buf, u32 type,
81 struct tipc_bearer *b)
82{
83 struct tipc_net *tn = net_generic(net, tipc_net_id);
84 struct tipc_msg *msg;
85 u32 dest_domain = b->domain;
86
87 msg = buf_msg(buf);
88 tipc_msg_init(tn->own_addr, msg, LINK_CONFIG, type,
89 MAX_H_SIZE, dest_domain);
90 msg_set_non_seq(msg, 1);
91 msg_set_node_sig(msg, tn->random);
92 msg_set_node_capabilities(msg, TIPC_NODE_CAPABILITIES);
93 msg_set_dest_domain(msg, dest_domain);
94 msg_set_bc_netid(msg, tn->net_id);
95 b->media->addr2msg(msg_media_addr(msg), &b->addr);
96}
97
98/**
99 * disc_dupl_alert - issue node address duplication alert
100 * @b: pointer to bearer detecting duplication
101 * @node_addr: duplicated node address
102 * @media_addr: media address advertised by duplicated node
103 */
104static void disc_dupl_alert(struct tipc_bearer *b, u32 node_addr,
105 struct tipc_media_addr *media_addr)
106{
107 char node_addr_str[16];
108 char media_addr_str[64];
109
110 tipc_addr_string_fill(node_addr_str, node_addr);
111 tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str),
112 media_addr);
113 pr_warn("Duplicate %s using %s seen on <%s>\n", node_addr_str,
114 media_addr_str, b->name);
115}
116
117/**
118 * tipc_disc_rcv - handle incoming discovery message (request or response)
119 * @net: the applicable net namespace
120 * @buf: buffer containing message
121 * @bearer: bearer that message arrived on
122 */
123void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
124 struct tipc_bearer *bearer)
125{
126 struct tipc_net *tn = net_generic(net, tipc_net_id);
127 struct tipc_media_addr maddr;
128 struct sk_buff *rskb;
129 struct tipc_msg *hdr = buf_msg(skb);
130 u32 ddom = msg_dest_domain(hdr);
131 u32 onode = msg_prevnode(hdr);
132 u32 net_id = msg_bc_netid(hdr);
133 u32 mtyp = msg_type(hdr);
134 u32 signature = msg_node_sig(hdr);
135 u16 caps = msg_node_capabilities(hdr);
136 bool respond = false;
137 bool dupl_addr = false;
138 int err;
139
140 err = bearer->media->msg2addr(bearer, &maddr, msg_media_addr(hdr));
141 kfree_skb(skb);
142 if (err)
143 return;
144
145 /* Ensure message from node is valid and communication is permitted */
146 if (net_id != tn->net_id)
147 return;
148 if (maddr.broadcast)
149 return;
150 if (!tipc_addr_domain_valid(ddom))
151 return;
152 if (!tipc_addr_node_valid(onode))
153 return;
154
155 if (in_own_node(net, onode)) {
156 if (memcmp(&maddr, &bearer->addr, sizeof(maddr)))
157 disc_dupl_alert(bearer, tn->own_addr, &maddr);
158 return;
159 }
160 if (!tipc_in_scope(ddom, tn->own_addr))
161 return;
162 if (!tipc_in_scope(bearer->domain, onode))
163 return;
164
165 tipc_node_check_dest(net, onode, bearer, caps, signature,
166 &maddr, &respond, &dupl_addr);
167 if (dupl_addr)
168 disc_dupl_alert(bearer, onode, &maddr);
169
170 /* Send response, if necessary */
171 if (respond && (mtyp == DSC_REQ_MSG)) {
172 rskb = tipc_buf_acquire(MAX_H_SIZE, GFP_ATOMIC);
173 if (!rskb)
174 return;
175 tipc_disc_init_msg(net, rskb, DSC_RESP_MSG, bearer);
176 tipc_bearer_xmit_skb(net, bearer->identity, rskb, &maddr);
177 }
178}
179
180/**
181 * disc_update - update frequency of periodic link setup requests
182 * @req: ptr to link request structure
183 *
184 * Reinitiates discovery process if discovery object has no associated nodes
185 * and is either not currently searching or is searching at a slow rate
186 */
187static void disc_update(struct tipc_link_req *req)
188{
189 if (!req->num_nodes) {
190 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) ||
191 (req->timer_intv > TIPC_LINK_REQ_FAST)) {
192 req->timer_intv = TIPC_LINK_REQ_INIT;
193 mod_timer(&req->timer, jiffies + req->timer_intv);
194 }
195 }
196}
197
198/**
199 * tipc_disc_add_dest - increment set of discovered nodes
200 * @req: ptr to link request structure
201 */
202void tipc_disc_add_dest(struct tipc_link_req *req)
203{
204 spin_lock_bh(&req->lock);
205 req->num_nodes++;
206 spin_unlock_bh(&req->lock);
207}
208
209/**
210 * tipc_disc_remove_dest - decrement set of discovered nodes
211 * @req: ptr to link request structure
212 */
213void tipc_disc_remove_dest(struct tipc_link_req *req)
214{
215 spin_lock_bh(&req->lock);
216 req->num_nodes--;
217 disc_update(req);
218 spin_unlock_bh(&req->lock);
219}
220
221/**
222 * disc_timeout - send a periodic link setup request
223 * @data: ptr to link request structure
224 *
225 * Called whenever a link setup request timer associated with a bearer expires.
226 */
227static void disc_timeout(unsigned long data)
228{
229 struct tipc_link_req *req = (struct tipc_link_req *)data;
230 struct sk_buff *skb;
231 int max_delay;
232
233 spin_lock_bh(&req->lock);
234
235 /* Stop searching if only desired node has been found */
236 if (tipc_node(req->domain) && req->num_nodes) {
237 req->timer_intv = TIPC_LINK_REQ_INACTIVE;
238 goto exit;
239 }
240
241 /*
242 * Send discovery message, then update discovery timer
243 *
244 * Keep doubling time between requests until limit is reached;
245 * hold at fast polling rate if don't have any associated nodes,
246 * otherwise hold at slow polling rate
247 */
248 skb = skb_clone(req->buf, GFP_ATOMIC);
249 if (skb)
250 tipc_bearer_xmit_skb(req->net, req->bearer_id, skb, &req->dest);
251 req->timer_intv *= 2;
252 if (req->num_nodes)
253 max_delay = TIPC_LINK_REQ_SLOW;
254 else
255 max_delay = TIPC_LINK_REQ_FAST;
256 if (req->timer_intv > max_delay)
257 req->timer_intv = max_delay;
258
259 mod_timer(&req->timer, jiffies + req->timer_intv);
260exit:
261 spin_unlock_bh(&req->lock);
262}
263
264/**
265 * tipc_disc_create - create object to send periodic link setup requests
266 * @net: the applicable net namespace
267 * @b: ptr to bearer issuing requests
268 * @dest: destination address for request messages
269 * @dest_domain: network domain to which links can be established
270 *
271 * Returns 0 if successful, otherwise -errno.
272 */
273int tipc_disc_create(struct net *net, struct tipc_bearer *b,
274 struct tipc_media_addr *dest, struct sk_buff **skb)
275{
276 struct tipc_link_req *req;
277
278 req = kmalloc(sizeof(*req), GFP_ATOMIC);
279 if (!req)
280 return -ENOMEM;
281 req->buf = tipc_buf_acquire(MAX_H_SIZE, GFP_ATOMIC);
282 if (!req->buf) {
283 kfree(req);
284 return -ENOMEM;
285 }
286
287 tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b);
288 memcpy(&req->dest, dest, sizeof(*dest));
289 req->net = net;
290 req->bearer_id = b->identity;
291 req->domain = b->domain;
292 req->num_nodes = 0;
293 req->timer_intv = TIPC_LINK_REQ_INIT;
294 spin_lock_init(&req->lock);
295 setup_timer(&req->timer, disc_timeout, (unsigned long)req);
296 mod_timer(&req->timer, jiffies + req->timer_intv);
297 b->link_req = req;
298 *skb = skb_clone(req->buf, GFP_ATOMIC);
299 return 0;
300}
301
302/**
303 * tipc_disc_delete - destroy object sending periodic link setup requests
304 * @req: ptr to link request structure
305 */
306void tipc_disc_delete(struct tipc_link_req *req)
307{
308 del_timer_sync(&req->timer);
309 kfree_skb(req->buf);
310 kfree(req);
311}
312
313/**
314 * tipc_disc_reset - reset object to send periodic link setup requests
315 * @net: the applicable net namespace
316 * @b: ptr to bearer issuing requests
317 * @dest_domain: network domain to which links can be established
318 */
319void tipc_disc_reset(struct net *net, struct tipc_bearer *b)
320{
321 struct tipc_link_req *req = b->link_req;
322 struct sk_buff *skb;
323
324 spin_lock_bh(&req->lock);
325 tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b);
326 req->net = net;
327 req->bearer_id = b->identity;
328 req->domain = b->domain;
329 req->num_nodes = 0;
330 req->timer_intv = TIPC_LINK_REQ_INIT;
331 mod_timer(&req->timer, jiffies + req->timer_intv);
332 skb = skb_clone(req->buf, GFP_ATOMIC);
333 if (skb)
334 tipc_bearer_xmit_skb(net, req->bearer_id, skb, &req->dest);
335 spin_unlock_bh(&req->lock);
336}