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 */
62 struct 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 */
tipc_disc_init_msg(struct net * net,struct sk_buff * skb,u32 mtyp,struct tipc_bearer * b)80 static 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
tipc_disc_msg_xmit(struct net * net,u32 mtyp,u32 dst,u32 src,u32 sugg_addr,struct tipc_media_addr * maddr,struct tipc_bearer * b)100 static 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 */
disc_dupl_alert(struct tipc_bearer * b,u32 node_addr,struct tipc_media_addr * media_addr)124 static 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 */
tipc_disc_addr_trial_msg(struct tipc_discoverer * d,struct tipc_media_addr * maddr,struct tipc_bearer * b,u32 dst,u32 src,u32 sugg_addr,u8 * peer_id,int mtyp)139 static 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 */
tipc_disc_rcv(struct net * net,struct sk_buff * skb,struct tipc_bearer * b)191 void 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 */
tipc_disc_add_dest(struct tipc_discoverer * d)257 void 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 */
tipc_disc_remove_dest(struct tipc_discoverer * d)266 void 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 */
tipc_disc_timeout(struct timer_list * t)287 static 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;
329 exit:
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 */
tipc_disc_create(struct net * net,struct tipc_bearer * b,struct tipc_media_addr * dest,struct sk_buff ** skb)344 int 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 */
tipc_disc_delete(struct tipc_discoverer * d)383 void 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 */
tipc_disc_reset(struct net * net,struct tipc_bearer * b)396 void 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 }
416