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1 | /* |
2 | Copyright (c) 2007, 2008 by Juliusz Chroboczek | |
3 | ||
4 | Permission is hereby granted, free of charge, to any person obtaining a copy | |
5 | of this software and associated documentation files (the "Software"), to deal | |
6 | in the Software without restriction, including without limitation the rights | |
7 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
8 | copies of the Software, and to permit persons to whom the Software is | |
9 | furnished to do so, subject to the following conditions: | |
10 | ||
11 | The above copyright notice and this permission notice shall be included in | |
12 | all copies or substantial portions of the Software. | |
13 | ||
14 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
15 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
16 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
17 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
18 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
19 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
20 | THE SOFTWARE. | |
21 | */ | |
22 | ||
23 | #include <stdlib.h> | |
24 | #include <string.h> | |
25 | #include <stdio.h> | |
26 | #include <sys/time.h> | |
27 | #include <time.h> | |
28 | ||
29 | #include <zebra.h> | |
30 | #include "if.h" | |
31 | ||
32 | #include "babel_main.h" | |
33 | #include "babeld.h" | |
34 | #include "util.h" | |
35 | #include "babel_interface.h" | |
36 | #include "neighbour.h" | |
37 | #include "source.h" | |
38 | #include "route.h" | |
39 | #include "message.h" | |
40 | #include "resend.h" | |
41 | ||
42 | struct neighbour *neighs = NULL; | |
43 | ||
44 | static struct neighbour * | |
45 | find_neighbour_nocreate(const unsigned char *address, struct interface *ifp) | |
46 | { | |
47 | struct neighbour *neigh; | |
48 | FOR_ALL_NEIGHBOURS(neigh) { | |
49 | if(memcmp(address, neigh->address, 16) == 0 && | |
50 | neigh->ifp == ifp) | |
51 | return neigh; | |
52 | } | |
53 | return NULL; | |
54 | } | |
55 | ||
56 | void | |
57 | flush_neighbour(struct neighbour *neigh) | |
58 | { | |
59 | debugf(BABEL_DEBUG_COMMON,"Flushing neighbour %s (reach 0x%04x)", | |
60 | format_address(neigh->address), neigh->reach); | |
61 | flush_neighbour_routes(neigh); | |
62 | if(unicast_neighbour == neigh) | |
63 | flush_unicast(1); | |
64 | flush_resends(neigh); | |
65 | ||
66 | if(neighs == neigh) { | |
67 | neighs = neigh->next; | |
68 | } else { | |
69 | struct neighbour *previous = neighs; | |
70 | while(previous->next != neigh) | |
71 | previous = previous->next; | |
72 | previous->next = neigh->next; | |
73 | } | |
74 | free(neigh); | |
75 | } | |
76 | ||
77 | struct neighbour * | |
78 | find_neighbour(const unsigned char *address, struct interface *ifp) | |
79 | { | |
80 | struct neighbour *neigh; | |
81 | const struct timeval zero = {0, 0}; | |
82 | ||
83 | neigh = find_neighbour_nocreate(address, ifp); | |
84 | if(neigh) | |
85 | return neigh; | |
86 | ||
87 | debugf(BABEL_DEBUG_COMMON,"Creating neighbour %s on %s.", | |
88 | format_address(address), ifp->name); | |
89 | ||
90 | neigh = malloc(sizeof(struct neighbour)); | |
91 | if(neigh == NULL) { | |
92 | zlog_err("malloc(neighbour): %s", safe_strerror(errno)); | |
93 | return NULL; | |
94 | } | |
95 | ||
96 | neigh->hello_seqno = -1; | |
97 | memcpy(neigh->address, address, 16); | |
98 | neigh->reach = 0; | |
99 | neigh->txcost = INFINITY; | |
100 | neigh->ihu_time = babel_now; | |
101 | neigh->hello_time = zero; | |
102 | neigh->hello_interval = 0; | |
103 | neigh->ihu_interval = 0; | |
104 | neigh->hello_send_us = 0; | |
105 | neigh->hello_rtt_receive_time = zero; | |
106 | neigh->rtt = 0; | |
107 | neigh->rtt_time = zero; | |
108 | neigh->ifp = ifp; | |
109 | neigh->next = neighs; | |
110 | neighs = neigh; | |
111 | send_hello(ifp); | |
112 | return neigh; | |
113 | } | |
114 | ||
115 | /* Recompute a neighbour's rxcost. Return true if anything changed. */ | |
116 | int | |
117 | update_neighbour(struct neighbour *neigh, int hello, int hello_interval) | |
118 | { | |
119 | int missed_hellos; | |
120 | int rc = 0; | |
121 | ||
122 | if(hello < 0) { | |
d11c6941 | 123 | if(neigh->hello_interval == 0) |
ca10883e DS |
124 | return rc; |
125 | missed_hellos = | |
126 | ((int)timeval_minus_msec(&babel_now, &neigh->hello_time) - | |
127 | neigh->hello_interval * 7) / | |
128 | (neigh->hello_interval * 10); | |
129 | if(missed_hellos <= 0) | |
130 | return rc; | |
131 | timeval_add_msec(&neigh->hello_time, &neigh->hello_time, | |
132 | missed_hellos * neigh->hello_interval * 10); | |
133 | } else { | |
134 | if(neigh->hello_seqno >= 0 && neigh->reach > 0) { | |
135 | missed_hellos = seqno_minus(hello, neigh->hello_seqno) - 1; | |
136 | if(missed_hellos < -8) { | |
137 | /* Probably a neighbour that rebooted and lost its seqno. | |
138 | Reboot the universe. */ | |
139 | neigh->reach = 0; | |
140 | missed_hellos = 0; | |
141 | rc = 1; | |
142 | } else if(missed_hellos < 0) { | |
143 | if(hello_interval > neigh->hello_interval) { | |
144 | /* This neighbour has increased its hello interval, | |
145 | and we didn't notice. */ | |
146 | neigh->reach <<= -missed_hellos; | |
147 | missed_hellos = 0; | |
148 | } else { | |
149 | /* Late hello. Probably due to the link layer buffering | |
150 | packets during a link outage. Ignore it, but reset | |
151 | the expected seqno. */ | |
152 | neigh->hello_seqno = hello; | |
153 | hello = -1; | |
154 | missed_hellos = 0; | |
155 | } | |
156 | rc = 1; | |
157 | } | |
158 | } else { | |
159 | missed_hellos = 0; | |
160 | } | |
161 | neigh->hello_time = babel_now; | |
162 | neigh->hello_interval = hello_interval; | |
163 | } | |
164 | ||
165 | if(missed_hellos > 0) { | |
166 | neigh->reach >>= missed_hellos; | |
167 | neigh->hello_seqno = seqno_plus(neigh->hello_seqno, missed_hellos); | |
ca10883e DS |
168 | rc = 1; |
169 | } | |
170 | ||
171 | if(hello >= 0) { | |
172 | neigh->hello_seqno = hello; | |
173 | neigh->reach >>= 1; | |
174 | neigh->reach |= 0x8000; | |
175 | if((neigh->reach & 0xFC00) != 0xFC00) | |
176 | rc = 1; | |
177 | } | |
178 | ||
179 | /* Make sure to give neighbours some feedback early after association */ | |
180 | if((neigh->reach & 0xBF00) == 0x8000) { | |
181 | /* A new neighbour */ | |
182 | send_hello(neigh->ifp); | |
183 | } else { | |
184 | /* Don't send hellos, in order to avoid a positive feedback loop. */ | |
185 | int a = (neigh->reach & 0xC000); | |
186 | int b = (neigh->reach & 0x3000); | |
187 | if((a == 0xC000 && b == 0) || (a == 0 && b == 0x3000)) { | |
188 | /* Reachability is either 1100 or 0011 */ | |
189 | send_self_update(neigh->ifp); | |
190 | } | |
191 | } | |
192 | ||
193 | if((neigh->reach & 0xFC00) == 0xC000) { | |
194 | /* This is a newish neighbour, let's request a full route dump. | |
195 | We ought to avoid this when the network is dense */ | |
196 | send_unicast_request(neigh, NULL, 0); | |
197 | send_ihu(neigh, NULL); | |
198 | } | |
199 | return rc; | |
200 | } | |
201 | ||
202 | static int | |
203 | reset_txcost(struct neighbour *neigh) | |
204 | { | |
205 | unsigned delay; | |
206 | ||
207 | delay = timeval_minus_msec(&babel_now, &neigh->ihu_time); | |
208 | ||
209 | if(neigh->ihu_interval > 0 && delay < neigh->ihu_interval * 10U * 3U) | |
210 | return 0; | |
211 | ||
212 | /* If we're losing a lot of packets, we probably lost an IHU too */ | |
213 | if(delay >= 180000 || (neigh->reach & 0xFFF0) == 0 || | |
214 | (neigh->ihu_interval > 0 && | |
215 | delay >= neigh->ihu_interval * 10U * 10U)) { | |
216 | neigh->txcost = INFINITY; | |
217 | neigh->ihu_time = babel_now; | |
218 | return 1; | |
219 | } | |
220 | ||
221 | return 0; | |
222 | } | |
223 | ||
224 | unsigned | |
225 | neighbour_txcost(struct neighbour *neigh) | |
226 | { | |
227 | return neigh->txcost; | |
228 | } | |
229 | ||
230 | unsigned | |
231 | check_neighbours() | |
232 | { | |
233 | struct neighbour *neigh; | |
234 | int changed, rc; | |
235 | unsigned msecs = 50000; | |
236 | ||
237 | debugf(BABEL_DEBUG_COMMON,"Checking neighbours."); | |
238 | ||
239 | neigh = neighs; | |
240 | while(neigh) { | |
241 | changed = update_neighbour(neigh, -1, 0); | |
242 | ||
243 | if(neigh->reach == 0 || | |
244 | neigh->hello_time.tv_sec > babel_now.tv_sec || /* clock stepped */ | |
245 | timeval_minus_msec(&babel_now, &neigh->hello_time) > 300000) { | |
246 | struct neighbour *old = neigh; | |
247 | neigh = neigh->next; | |
248 | flush_neighbour(old); | |
249 | continue; | |
250 | } | |
251 | ||
252 | rc = reset_txcost(neigh); | |
253 | changed = changed || rc; | |
254 | ||
255 | update_neighbour_metric(neigh, changed); | |
256 | ||
257 | if(neigh->hello_interval > 0) | |
258 | msecs = MIN(msecs, neigh->hello_interval * 10U); | |
259 | if(neigh->ihu_interval > 0) | |
260 | msecs = MIN(msecs, neigh->ihu_interval * 10U); | |
261 | neigh = neigh->next; | |
262 | } | |
263 | ||
264 | return msecs; | |
265 | } | |
266 | ||
267 | unsigned | |
268 | neighbour_rxcost(struct neighbour *neigh) | |
269 | { | |
270 | unsigned delay; | |
271 | unsigned short reach = neigh->reach; | |
272 | ||
273 | delay = timeval_minus_msec(&babel_now, &neigh->hello_time); | |
274 | ||
275 | if((reach & 0xFFF0) == 0 || delay >= 180000) { | |
276 | return INFINITY; | |
277 | } else if(babel_get_if_nfo(neigh->ifp)->flags & BABEL_IF_LQ) { | |
278 | int sreach = | |
279 | ((reach & 0x8000) >> 2) + | |
280 | ((reach & 0x4000) >> 1) + | |
281 | (reach & 0x3FFF); | |
282 | /* 0 <= sreach <= 0x7FFF */ | |
283 | int cost = (0x8000 * babel_get_if_nfo(neigh->ifp)->cost) / (sreach + 1); | |
284 | /* cost >= interface->cost */ | |
285 | if(delay >= 40000) | |
286 | cost = (cost * (delay - 20000) + 10000) / 20000; | |
287 | return MIN(cost, INFINITY); | |
288 | } else { | |
289 | /* To lose one hello is a misfortune, to lose two is carelessness. */ | |
290 | if((reach & 0xC000) == 0xC000) | |
291 | return babel_get_if_nfo(neigh->ifp)->cost; | |
292 | else if((reach & 0xC000) == 0) | |
293 | return INFINITY; | |
294 | else if((reach & 0x2000)) | |
295 | return babel_get_if_nfo(neigh->ifp)->cost; | |
296 | else | |
297 | return INFINITY; | |
298 | } | |
299 | } | |
300 | ||
301 | unsigned | |
302 | neighbour_rttcost(struct neighbour *neigh) | |
303 | { | |
304 | struct interface *ifp = neigh->ifp; | |
305 | babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp); | |
306 | ||
307 | if(!babel_ifp->max_rtt_penalty || !valid_rtt(neigh)) | |
308 | return 0; | |
309 | ||
310 | /* Function: linear behaviour between rtt_min and rtt_max. */ | |
311 | if(neigh->rtt <= babel_ifp->rtt_min) { | |
312 | return 0; | |
313 | } else if(neigh->rtt <= babel_ifp->rtt_max) { | |
314 | unsigned long long tmp = | |
315 | (unsigned long long)babel_ifp->max_rtt_penalty * | |
316 | (neigh->rtt - babel_ifp->rtt_min) / | |
317 | (babel_ifp->rtt_max - babel_ifp->rtt_min); | |
318 | assert((tmp & 0x7FFFFFFF) == tmp); | |
319 | return tmp; | |
320 | } else { | |
321 | return babel_ifp->max_rtt_penalty; | |
322 | } | |
323 | } | |
324 | ||
325 | unsigned | |
326 | neighbour_cost(struct neighbour *neigh) | |
327 | { | |
328 | unsigned a, b, cost; | |
329 | ||
330 | if(!if_up(neigh->ifp)) | |
331 | return INFINITY; | |
332 | ||
333 | a = neighbour_txcost(neigh); | |
334 | ||
335 | if(a >= INFINITY) | |
336 | return INFINITY; | |
337 | ||
338 | b = neighbour_rxcost(neigh); | |
339 | if(b >= INFINITY) | |
340 | return INFINITY; | |
341 | ||
342 | if(!(babel_get_if_nfo(neigh->ifp)->flags & BABEL_IF_LQ) | |
343 | || (a < 256 && b < 256)) { | |
344 | cost = a; | |
345 | } else { | |
346 | /* a = 256/alpha, b = 256/beta, where alpha and beta are the expected | |
347 | probabilities of a packet getting through in the direct and reverse | |
348 | directions. */ | |
349 | a = MAX(a, 256); | |
350 | b = MAX(b, 256); | |
351 | /* 1/(alpha * beta), which is just plain ETX. */ | |
352 | /* Since a and b are capped to 16 bits, overflow is impossible. */ | |
353 | cost = (a * b + 128) >> 8; | |
354 | } | |
355 | ||
356 | cost += neighbour_rttcost(neigh); | |
357 | ||
358 | return MIN(cost, INFINITY); | |
359 | } | |
360 | ||
361 | int | |
362 | valid_rtt(struct neighbour *neigh) | |
363 | { | |
364 | return (timeval_minus_msec(&babel_now, &neigh->rtt_time) < 180000) ? 1 : 0; | |
365 | } |