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
tipc_disc_init_msg(u32 type,u32 dest_domain,struct tipc_bearer * b_ptr)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_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 */
98
disc_dupl_alert(struct tipc_bearer * b_ptr,u32 node_addr,struct tipc_media_addr * media_addr)99 static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr,
100 struct tipc_media_addr *media_addr)
101 {
102 char node_addr_str[16];
103 char media_addr_str[64];
104 struct print_buf pb;
105
106 tipc_addr_string_fill(node_addr_str, node_addr);
107 tipc_printbuf_init(&pb, media_addr_str, sizeof(media_addr_str));
108 tipc_media_addr_printf(&pb, media_addr);
109 tipc_printbuf_validate(&pb);
110 warn("Duplicate %s using %s seen on <%s>\n",
111 node_addr_str, media_addr_str, b_ptr->name);
112 }
113
114 /**
115 * tipc_disc_recv_msg - handle incoming link setup message (request or response)
116 * @buf: buffer containing message
117 * @b_ptr: bearer that message arrived on
118 */
119
tipc_disc_recv_msg(struct sk_buff * buf,struct tipc_bearer * b_ptr)120 void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr)
121 {
122 struct tipc_node *n_ptr;
123 struct tipc_link *link;
124 struct tipc_media_addr media_addr, *addr;
125 struct sk_buff *rbuf;
126 struct tipc_msg *msg = buf_msg(buf);
127 u32 dest = msg_dest_domain(msg);
128 u32 orig = msg_prevnode(msg);
129 u32 net_id = msg_bc_netid(msg);
130 u32 type = msg_type(msg);
131 int link_fully_up;
132
133 media_addr.broadcast = 1;
134 b_ptr->media->msg2addr(&media_addr, msg_media_addr(msg));
135 buf_discard(buf);
136
137 /* Validate discovery message from requesting node */
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 link = n_ptr->links[b_ptr->identity];
166
167 /* Create a link endpoint for this bearer, if necessary */
168 if (!link) {
169 link = tipc_link_create(n_ptr, b_ptr, &media_addr);
170 if (!link) {
171 tipc_node_unlock(n_ptr);
172 return;
173 }
174 }
175
176 /*
177 * Ensure requesting node's media address is correct
178 *
179 * If media address doesn't match and the link is working, reject the
180 * request (must be from a duplicate node).
181 *
182 * If media address doesn't match and the link is not working, accept
183 * the new media address and reset the link to ensure it starts up
184 * cleanly.
185 */
186 addr = &link->media_addr;
187 if (memcmp(addr, &media_addr, sizeof(*addr))) {
188 if (tipc_link_is_up(link) || (!link->started)) {
189 disc_dupl_alert(b_ptr, orig, &media_addr);
190 tipc_node_unlock(n_ptr);
191 return;
192 }
193 warn("Resetting link <%s>, peer interface address changed\n",
194 link->name);
195 memcpy(addr, &media_addr, sizeof(*addr));
196 tipc_link_reset(link);
197 }
198
199 /* Accept discovery message & send response, if necessary */
200 link_fully_up = link_working_working(link);
201
202 if ((type == DSC_REQ_MSG) && !link_fully_up && !b_ptr->blocked) {
203 rbuf = tipc_disc_init_msg(DSC_RESP_MSG, orig, b_ptr);
204 if (rbuf) {
205 b_ptr->media->send_msg(rbuf, b_ptr, &media_addr);
206 buf_discard(rbuf);
207 }
208 }
209
210 tipc_node_unlock(n_ptr);
211 }
212
213 /**
214 * disc_update - update frequency of periodic link setup requests
215 * @req: ptr to link request structure
216 *
217 * Reinitiates discovery process if discovery object has no associated nodes
218 * and is either not currently searching or is searching at a slow rate
219 */
220
disc_update(struct tipc_link_req * req)221 static void disc_update(struct tipc_link_req *req)
222 {
223 if (!req->num_nodes) {
224 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) ||
225 (req->timer_intv > TIPC_LINK_REQ_FAST)) {
226 req->timer_intv = TIPC_LINK_REQ_INIT;
227 k_start_timer(&req->timer, req->timer_intv);
228 }
229 }
230 }
231
232 /**
233 * tipc_disc_add_dest - increment set of discovered nodes
234 * @req: ptr to link request structure
235 */
236
tipc_disc_add_dest(struct tipc_link_req * req)237 void tipc_disc_add_dest(struct tipc_link_req *req)
238 {
239 req->num_nodes++;
240 }
241
242 /**
243 * tipc_disc_remove_dest - decrement set of discovered nodes
244 * @req: ptr to link request structure
245 */
246
tipc_disc_remove_dest(struct tipc_link_req * req)247 void tipc_disc_remove_dest(struct tipc_link_req *req)
248 {
249 req->num_nodes--;
250 disc_update(req);
251 }
252
253 /**
254 * disc_send_msg - send link setup request message
255 * @req: ptr to link request structure
256 */
257
disc_send_msg(struct tipc_link_req * req)258 static void disc_send_msg(struct tipc_link_req *req)
259 {
260 if (!req->bearer->blocked)
261 tipc_bearer_send(req->bearer, req->buf, &req->dest);
262 }
263
264 /**
265 * disc_timeout - send a periodic link setup request
266 * @req: ptr to link request structure
267 *
268 * Called whenever a link setup request timer associated with a bearer expires.
269 */
270
disc_timeout(struct tipc_link_req * req)271 static void disc_timeout(struct tipc_link_req *req)
272 {
273 int max_delay;
274
275 spin_lock_bh(&req->bearer->lock);
276
277 /* Stop searching if only desired node has been found */
278
279 if (tipc_node(req->domain) && req->num_nodes) {
280 req->timer_intv = TIPC_LINK_REQ_INACTIVE;
281 goto exit;
282 }
283
284 /*
285 * Send discovery message, then update discovery timer
286 *
287 * Keep doubling time between requests until limit is reached;
288 * hold at fast polling rate if don't have any associated nodes,
289 * otherwise hold at slow polling rate
290 */
291
292 disc_send_msg(req);
293
294 req->timer_intv *= 2;
295 if (req->num_nodes)
296 max_delay = TIPC_LINK_REQ_SLOW;
297 else
298 max_delay = TIPC_LINK_REQ_FAST;
299 if (req->timer_intv > max_delay)
300 req->timer_intv = max_delay;
301
302 k_start_timer(&req->timer, req->timer_intv);
303 exit:
304 spin_unlock_bh(&req->bearer->lock);
305 }
306
307 /**
308 * tipc_disc_create - create object to send periodic link setup requests
309 * @b_ptr: ptr to bearer issuing requests
310 * @dest: destination address for request messages
311 * @dest_domain: network domain to which links can be established
312 *
313 * Returns 0 if successful, otherwise -errno.
314 */
315
tipc_disc_create(struct tipc_bearer * b_ptr,struct tipc_media_addr * dest,u32 dest_domain)316 int tipc_disc_create(struct tipc_bearer *b_ptr,
317 struct tipc_media_addr *dest, u32 dest_domain)
318 {
319 struct tipc_link_req *req;
320
321 req = kmalloc(sizeof(*req), GFP_ATOMIC);
322 if (!req)
323 return -ENOMEM;
324
325 req->buf = tipc_disc_init_msg(DSC_REQ_MSG, dest_domain, b_ptr);
326 if (!req->buf) {
327 kfree(req);
328 return -ENOMSG;
329 }
330
331 memcpy(&req->dest, dest, sizeof(*dest));
332 req->bearer = b_ptr;
333 req->domain = dest_domain;
334 req->num_nodes = 0;
335 req->timer_intv = TIPC_LINK_REQ_INIT;
336 k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req);
337 k_start_timer(&req->timer, req->timer_intv);
338 b_ptr->link_req = req;
339 disc_send_msg(req);
340 return 0;
341 }
342
343 /**
344 * tipc_disc_delete - destroy object sending periodic link setup requests
345 * @req: ptr to link request structure
346 */
347
tipc_disc_delete(struct tipc_link_req * req)348 void tipc_disc_delete(struct tipc_link_req *req)
349 {
350 k_cancel_timer(&req->timer);
351 k_term_timer(&req->timer);
352 buf_discard(req->buf);
353 kfree(req);
354 }
355
356