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