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1 | /* |
2 | * net/tipc/discover.c |
3 | * |
4 | * Copyright (c) 2003-2006, Ericsson AB |
5 | * Copyright (c) 2005-2006, 2010-2011, Wind River Systems |
6 | * All rights reserved. |
7 | * |
8 | * Redistribution and use in source and binary forms, with or without |
9 | * modification, are permitted provided that the following conditions are met: |
10 | * |
11 | * 1. Redistributions of source code must retain the above copyright |
12 | * notice, this list of conditions and the following disclaimer. |
13 | * 2. Redistributions in binary form must reproduce the above copyright |
14 | * notice, this list of conditions and the following disclaimer in the |
15 | * documentation and/or other materials provided with the distribution. |
16 | * 3. Neither the names of the copyright holders nor the names of its |
17 | * contributors may be used to endorse or promote products derived from |
18 | * this software without specific prior written permission. |
19 | * |
20 | * Alternatively, this software may be distributed under the terms of the |
21 | * GNU General Public License ("GPL") version 2 as published by the Free |
22 | * Software Foundation. |
23 | * |
24 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
25 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
28 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
29 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
30 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
31 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
32 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
33 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
34 | * POSSIBILITY OF SUCH DAMAGE. |
35 | */ |
36 | |
37 | #include "core.h" |
38 | #include "link.h" |
39 | #include "discover.h" |
40 | |
41 | #define TIPC_LINK_REQ_INIT 125 /* min delay during bearer start up */ |
42 | #define TIPC_LINK_REQ_FAST 1000 /* max delay if bearer has no links */ |
43 | #define TIPC_LINK_REQ_SLOW 60000 /* max delay if bearer has links */ |
44 | #define TIPC_LINK_REQ_INACTIVE 0xffffffff /* indicates no timer in use */ |
45 | |
46 | |
47 | /** |
48 | * struct tipc_link_req - information about an ongoing link setup request |
49 | * @bearer: bearer issuing requests |
50 | * @dest: destination address for request messages |
51 | * @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 | */ |
57 | struct 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 | */ |
73 | |
74 | static struct sk_buff *tipc_disc_init_msg(u32 type, |
75 | u32 dest_domain, |
76 | struct tipc_bearer *b_ptr) |
77 | { |
78 | struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE); |
79 | struct tipc_msg *msg; |
80 | |
81 | if (buf) { |
82 | msg = buf_msg(buf); |
83 | tipc_msg_init(msg, LINK_CONFIG, type, INT_H_SIZE, dest_domain); |
84 | msg_set_non_seq(msg, 1); |
85 | msg_set_node_sig(msg, tipc_random); |
86 | msg_set_dest_domain(msg, dest_domain); |
87 | msg_set_bc_netid(msg, tipc_net_id); |
88 | b_ptr->media->addr2msg(&b_ptr->addr, msg_media_addr(msg)); |
89 | } |
90 | return buf; |
91 | } |
92 | |
93 | /** |
94 | * disc_dupl_alert - issue node address duplication alert |
95 | * @b_ptr: pointer to bearer detecting duplication |
96 | * @node_addr: duplicated node address |
97 | * @media_addr: media address advertised by duplicated node |
98 | */ |
99 | |
100 | static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr, |
101 | struct tipc_media_addr *media_addr) |
102 | { |
103 | char node_addr_str[16]; |
104 | char media_addr_str[64]; |
105 | struct print_buf pb; |
106 | |
107 | tipc_addr_string_fill(node_addr_str, node_addr); |
108 | tipc_printbuf_init(&pb, media_addr_str, sizeof(media_addr_str)); |
109 | tipc_media_addr_printf(&pb, media_addr); |
110 | tipc_printbuf_validate(&pb); |
111 | warn("Duplicate %s using %s seen on <%s>\n", |
112 | node_addr_str, media_addr_str, b_ptr->name); |
113 | } |
114 | |
115 | /** |
116 | * tipc_disc_recv_msg - handle incoming link setup message (request or response) |
117 | * @buf: buffer containing message |
118 | * @b_ptr: bearer that message arrived on |
119 | */ |
120 | |
121 | void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr) |
122 | { |
123 | struct tipc_node *n_ptr; |
124 | struct tipc_link *link; |
125 | struct tipc_media_addr media_addr; |
126 | struct sk_buff *rbuf; |
127 | struct tipc_msg *msg = buf_msg(buf); |
128 | u32 dest = msg_dest_domain(msg); |
129 | u32 orig = msg_prevnode(msg); |
130 | u32 net_id = msg_bc_netid(msg); |
131 | u32 type = msg_type(msg); |
132 | u32 signature = msg_node_sig(msg); |
133 | int addr_mismatch; |
134 | int link_fully_up; |
135 | |
136 | media_addr.broadcast = 1; |
137 | b_ptr->media->msg2addr(&media_addr, msg_media_addr(msg)); |
138 | kfree_skb(buf); |
139 | |
140 | /* Ensure message from node is valid and communication is permitted */ |
141 | if (net_id != tipc_net_id) |
142 | return; |
143 | if (media_addr.broadcast) |
144 | return; |
145 | if (!tipc_addr_domain_valid(dest)) |
146 | return; |
147 | if (!tipc_addr_node_valid(orig)) |
148 | return; |
149 | if (orig == tipc_own_addr) { |
150 | if (memcmp(&media_addr, &b_ptr->addr, sizeof(media_addr))) |
151 | disc_dupl_alert(b_ptr, tipc_own_addr, &media_addr); |
152 | return; |
153 | } |
154 | if (!tipc_in_scope(dest, tipc_own_addr)) |
155 | return; |
156 | if (!tipc_in_scope(b_ptr->link_req->domain, orig)) |
157 | return; |
158 | |
159 | /* Locate structure corresponding to requesting node */ |
160 | n_ptr = tipc_node_find(orig); |
161 | if (!n_ptr) { |
162 | n_ptr = tipc_node_create(orig); |
163 | if (!n_ptr) |
164 | return; |
165 | } |
166 | tipc_node_lock(n_ptr); |
167 | |
168 | /* Prepare to validate requesting node's signature and media address */ |
169 | link = n_ptr->links[b_ptr->identity]; |
170 | addr_mismatch = (link != NULL) && |
171 | memcmp(&link->media_addr, &media_addr, sizeof(media_addr)); |
172 | |
173 | /* |
174 | * Ensure discovery message's signature is correct |
175 | * |
176 | * If signature is incorrect and there is no working link to the node, |
177 | * accept the new signature but invalidate all existing links to the |
178 | * node so they won't re-activate without a new discovery message. |
179 | * |
180 | * If signature is incorrect and the requested link to the node is |
181 | * working, accept the new signature. (This is an instance of delayed |
182 | * rediscovery, where a link endpoint was able to re-establish contact |
183 | * with its peer endpoint on a node that rebooted before receiving a |
184 | * discovery message from that node.) |
185 | * |
186 | * If signature is incorrect and there is a working link to the node |
187 | * that is not the requested link, reject the request (must be from |
188 | * a duplicate node). |
189 | */ |
190 | if (signature != n_ptr->signature) { |
191 | if (n_ptr->working_links == 0) { |
192 | struct tipc_link *curr_link; |
193 | int i; |
194 | |
195 | for (i = 0; i < MAX_BEARERS; i++) { |
196 | curr_link = n_ptr->links[i]; |
197 | if (curr_link) { |
198 | memset(&curr_link->media_addr, 0, |
199 | sizeof(media_addr)); |
200 | tipc_link_reset(curr_link); |
201 | } |
202 | } |
203 | addr_mismatch = (link != NULL); |
204 | } else if (tipc_link_is_up(link) && !addr_mismatch) { |
205 | /* delayed rediscovery */ |
206 | } else { |
207 | disc_dupl_alert(b_ptr, orig, &media_addr); |
208 | tipc_node_unlock(n_ptr); |
209 | return; |
210 | } |
211 | n_ptr->signature = signature; |
212 | } |
213 | |
214 | /* |
215 | * Ensure requesting node's media address is correct |
216 | * |
217 | * If media address doesn't match and the link is working, reject the |
218 | * request (must be from a duplicate node). |
219 | * |
220 | * If media address doesn't match and the link is not working, accept |
221 | * the new media address and reset the link to ensure it starts up |
222 | * cleanly. |
223 | */ |
224 | |
225 | if (addr_mismatch) { |
226 | if (tipc_link_is_up(link)) { |
227 | disc_dupl_alert(b_ptr, orig, &media_addr); |
228 | tipc_node_unlock(n_ptr); |
229 | return; |
230 | } else { |
231 | memcpy(&link->media_addr, &media_addr, |
232 | sizeof(media_addr)); |
233 | tipc_link_reset(link); |
234 | } |
235 | } |
236 | |
237 | /* Create a link endpoint for this bearer, if necessary */ |
238 | if (!link) { |
239 | link = tipc_link_create(n_ptr, b_ptr, &media_addr); |
240 | if (!link) { |
241 | tipc_node_unlock(n_ptr); |
242 | return; |
243 | } |
244 | } |
245 | |
246 | /* Accept discovery message & send response, if necessary */ |
247 | link_fully_up = link_working_working(link); |
248 | |
249 | if ((type == DSC_REQ_MSG) && !link_fully_up && !b_ptr->blocked) { |
250 | rbuf = tipc_disc_init_msg(DSC_RESP_MSG, orig, b_ptr); |
251 | if (rbuf) { |
252 | b_ptr->media->send_msg(rbuf, b_ptr, &media_addr); |
253 | kfree_skb(rbuf); |
254 | } |
255 | } |
256 | |
257 | tipc_node_unlock(n_ptr); |
258 | } |
259 | |
260 | /** |
261 | * disc_update - update frequency of periodic link setup requests |
262 | * @req: ptr to link request structure |
263 | * |
264 | * Reinitiates discovery process if discovery object has no associated nodes |
265 | * and is either not currently searching or is searching at a slow rate |
266 | */ |
267 | |
268 | static void disc_update(struct tipc_link_req *req) |
269 | { |
270 | if (!req->num_nodes) { |
271 | if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) || |
272 | (req->timer_intv > TIPC_LINK_REQ_FAST)) { |
273 | req->timer_intv = TIPC_LINK_REQ_INIT; |
274 | k_start_timer(&req->timer, req->timer_intv); |
275 | } |
276 | } |
277 | } |
278 | |
279 | /** |
280 | * tipc_disc_add_dest - increment set of discovered nodes |
281 | * @req: ptr to link request structure |
282 | */ |
283 | |
284 | void tipc_disc_add_dest(struct tipc_link_req *req) |
285 | { |
286 | req->num_nodes++; |
287 | } |
288 | |
289 | /** |
290 | * tipc_disc_remove_dest - decrement set of discovered nodes |
291 | * @req: ptr to link request structure |
292 | */ |
293 | |
294 | void tipc_disc_remove_dest(struct tipc_link_req *req) |
295 | { |
296 | req->num_nodes--; |
297 | disc_update(req); |
298 | } |
299 | |
300 | /** |
301 | * disc_send_msg - send link setup request message |
302 | * @req: ptr to link request structure |
303 | */ |
304 | |
305 | static void disc_send_msg(struct tipc_link_req *req) |
306 | { |
307 | if (!req->bearer->blocked) |
308 | tipc_bearer_send(req->bearer, req->buf, &req->dest); |
309 | } |
310 | |
311 | /** |
312 | * disc_timeout - send a periodic link setup request |
313 | * @req: ptr to link request structure |
314 | * |
315 | * Called whenever a link setup request timer associated with a bearer expires. |
316 | */ |
317 | |
318 | static void disc_timeout(struct tipc_link_req *req) |
319 | { |
320 | int max_delay; |
321 | |
322 | spin_lock_bh(&req->bearer->lock); |
323 | |
324 | /* Stop searching if only desired node has been found */ |
325 | |
326 | if (tipc_node(req->domain) && req->num_nodes) { |
327 | req->timer_intv = TIPC_LINK_REQ_INACTIVE; |
328 | goto exit; |
329 | } |
330 | |
331 | /* |
332 | * Send discovery message, then update discovery timer |
333 | * |
334 | * Keep doubling time between requests until limit is reached; |
335 | * hold at fast polling rate if don't have any associated nodes, |
336 | * otherwise hold at slow polling rate |
337 | */ |
338 | |
339 | disc_send_msg(req); |
340 | |
341 | req->timer_intv *= 2; |
342 | if (req->num_nodes) |
343 | max_delay = TIPC_LINK_REQ_SLOW; |
344 | else |
345 | max_delay = TIPC_LINK_REQ_FAST; |
346 | if (req->timer_intv > max_delay) |
347 | req->timer_intv = max_delay; |
348 | |
349 | k_start_timer(&req->timer, req->timer_intv); |
350 | exit: |
351 | spin_unlock_bh(&req->bearer->lock); |
352 | } |
353 | |
354 | /** |
355 | * tipc_disc_create - create object to send periodic link setup requests |
356 | * @b_ptr: ptr to bearer issuing requests |
357 | * @dest: destination address for request messages |
358 | * @dest_domain: network domain to which links can be established |
359 | * |
360 | * Returns 0 if successful, otherwise -errno. |
361 | */ |
362 | |
363 | int tipc_disc_create(struct tipc_bearer *b_ptr, |
364 | struct tipc_media_addr *dest, u32 dest_domain) |
365 | { |
366 | struct tipc_link_req *req; |
367 | |
368 | req = kmalloc(sizeof(*req), GFP_ATOMIC); |
369 | if (!req) |
370 | return -ENOMEM; |
371 | |
372 | req->buf = tipc_disc_init_msg(DSC_REQ_MSG, dest_domain, b_ptr); |
373 | if (!req->buf) { |
374 | kfree(req); |
375 | return -ENOMSG; |
376 | } |
377 | |
378 | memcpy(&req->dest, dest, sizeof(*dest)); |
379 | req->bearer = b_ptr; |
380 | req->domain = dest_domain; |
381 | req->num_nodes = 0; |
382 | req->timer_intv = TIPC_LINK_REQ_INIT; |
383 | k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req); |
384 | k_start_timer(&req->timer, req->timer_intv); |
385 | b_ptr->link_req = req; |
386 | disc_send_msg(req); |
387 | return 0; |
388 | } |
389 | |
390 | /** |
391 | * tipc_disc_delete - destroy object sending periodic link setup requests |
392 | * @req: ptr to link request structure |
393 | */ |
394 | |
395 | void tipc_disc_delete(struct tipc_link_req *req) |
396 | { |
397 | k_cancel_timer(&req->timer); |
398 | k_term_timer(&req->timer); |
399 | kfree_skb(req->buf); |
400 | kfree(req); |
401 | } |
402 | |
403 |
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