NS2中AODV协议解释.docx

分类：ns仿真2012-05-28 20:231285人阅读评论(5)收藏举报dststructrtfdelaytclfunctioncppview plaincopy1. /#include2. 3. #include4. #include5. #include6. #include7. /#include8. 9. #definemax(a,b)(a)(b)?(a):(b)10. #defineCURRENT_TIMEScheduler:instance().clock()11. 12. /#defineDEBUG13. /#defineERROR14. 15. #ifdefDEBUG16. staticintextra_route_reply=0;17. staticintlimit_route_request=0;18. staticintroute_request=0;19. #endif20. 21. 22. /*23. TCLHooks24. */25. 26. 27. inthdr_aodv:offset_;28. staticclassAODVHeaderClass:publicPacketHeaderClass29. public:30. AODVHeaderClass():PacketHeaderClass(PacketHeader/AODV,31. sizeof(hdr_all_aodv)32. bind_offset(&hdr_aodv:offset_);33. 34. class_rtProtoAODV_hdr;35. /*AODVclass只有两个函数,构造函数和creat函数*/36. staticclassAODVclass:publicTclClass37. public:38. AODVclass():TclClass(Agent/AODV)39. TclObject*create(intargc,constchar*const*argv)40. assert(argc=5);41. /return(newAODV(nsaddr_t)atoi(argv4);42. return(newAODV(nsaddr_t)Address:instance().str2addr(argv4);43. 44. class_rtProtoAODV;45. 46. /*command函数实现了命令的分发*/47. int48. AODV:command(intargc,constchar*const*argv)49. if(argc=2)/命令的参数个数是250. Tcl&tcl=Tcl:instance();51. 52. if(strncasecmp(argv1,id,2)=0)/命令所要求的操作为id53. tcl.resultf(%d,index);54. returnTCL_OK;55. 56. 57. if(strncasecmp(argv1,start,2)=0)/命令所要求的操作为start58. btimer.handle(Event*)0);59. 60. #ifndefAODV_LINK_LAYER_DETECTION61. htimer.handle(Event*)0);62. ntimer.handle(Event*)0);63. #endif/LINKLAYERDETECTION64. 65. rtimer.handle(Event*)0);66. returnTCL_OK;67. 68. 69. elseif(argc=3)/命令参数个数等于370. if(strcmp(argv1,index)=0)/命令所要求的操作为index71. index=atoi(argv2);72. returnTCL_OK;73. 74. /命令所要求的操作为log-target或者tracetarget75. elseif(strcmp(argv1,log-target)=0|strcmp(argv1,tracetarget)=0)76. logtarget=(Trace*)TclObject:lookup(argv2);77. if(logtarget=0)78. returnTCL_ERROR;79. returnTCL_OK;80. 81. elseif(strcmp(argv1,drop-target)=0)82. 83. /命令所要求的操作为drop-target84. intstat=mand(argc,argv);85. if(stat!=TCL_OK)returnstat;86. returnAgent:command(argc,argv);87. 88. 89. /命令所要求的操作if-queue90. elseif(strcmp(argv1,if-queue)=0)91. ifqueue=(PriQueue*)TclObject:lookup(argv2);92. 93. if(ifqueue=0)94. returnTCL_ERROR;95. returnTCL_OK;96. 97. /命令所要求的操作为port-dmux98. elseif(strcmp(argv1,port-dmux)=0)99. dmux_=(PortClassifier*)TclObject:lookup(argv2);100. if(dmux_=0)101. fprintf(stderr,%s:%slookupof%sfailedn,_FILE_,102. argv1,argv2);103. returnTCL_ERROR;104. 105. returnTCL_OK;106. 107. 108. returnAgent:command(argc,argv);109. 110. 111. /*112. Constructor113. */114. 115. AODV:AODV(nsaddr_tid):Agent(PT_AODV),116. btimer(this),htimer(this),ntimer(this),117. rtimer(this),lrtimer(this),rqueue()118. 119. 120. index=id;121. seqno=2;122. bid=1;123. 124. LIST_INIT(&nbhead);125. LIST_INIT(&bihead);126. 127. logtarget=0;128. ifqueue=0;129. 130. 131. /*132. Timers133. */134. /广播定时器135. void136. BroadcastTimer:handle(Event*)137. agent-id_purge();138. Scheduler:instance().schedule(this,&intr,BCAST_ID_SAVE);139. 140. /hello报文定时器141. void142. HelloTimer:handle(Event*)143. agent-sendHello();144. doubleinterval=MinHelloInterval+145. (MaxHelloInterval-MinHelloInterval)*Random:uniform();146. assert(interval=0);147. Scheduler:instance().schedule(this,&intr,interval);148. 149. /邻居定时器150. void151. NeighborTimer:handle(Event*)152. agent-nb_purge();153. Scheduler:instance().schedule(this,&intr,HELLO_INTERVAL);154. 155. 路由缓存定时器156. void157. RouteCacheTimer:handle(Event*)158. agent-rt_purge();159. #defineFREQUENCY0.5/sec160. Scheduler:instance().schedule(this,&intr,FREQUENCY);161. 162. /路由缓存定时器163. void164. LocalRepairTimer:handle(Event*p)/SRD:5/4/99165. aodv_rt_entry*rt;166. structhdr_ip*ih=HDR_IP(Packet*)p);167. 168. /*yougethereafterthetimeoutinalocalrepairattempt*/169. /*fprintf(stderr,%sn,_FUNCTION_);*/170. 171. 172. rt=agent-rtable.rt_lookup(ih-daddr();173. 174. if(rt&rt-rt_flags!=RTF_UP)175. /routeisyettoberepaired176. /Iwillbeconservativeandbringdowntheroute177. /andsendrouteerrorsupstream.178. /*Thefollowingassertfails,notsurewhy*/179. /*assert(rt-rt_flags=RTF_IN_REPAIR);*/180. 181. /rt-rt_seqno+;182. agent-rt_down(rt);183. /sendRERR184. #ifdefDEBUG185. fprintf(stderr,Node%d:Dst-%d,failedlocalrepairn,index,rt-rt_dst);186. #endif187. 188. Packet:free(Packet*)p);189. 190. 191. 192. /*193. BroadcastIDManagementFunctions194. */195. 196. 197. void198. AODV:id_insert(nsaddr_tid,u_int32_tbid)199. BroadcastID*b=newBroadcastID(id,bid);200. 201. assert(b);202. b-expire=CURRENT_TIME+BCAST_ID_SAVE;203. LIST_INSERT_HEAD(&bihead,b,link);204. 205. 206. /*SRD*/207. bool208. AODV:id_lookup(nsaddr_tid,u_int32_tbid)209. BroadcastID*b=bihead.lh_first;210. 211. /Searchthelistforamatchofsourceandbid212. for(;b;b=b-link.le_next)213. if(b-src=id)&(b-id=bid)214. returntrue;215. 216. returnfalse;217. 218. 219. void220. AODV:id_purge()221. BroadcastID*b=bihead.lh_first;222. BroadcastID*bn;223. doublenow=CURRENT_TIME;224. 225. for(;b;b=bn)226. bn=b-link.le_next;227. if(b-expire=now)228. LIST_REMOVE(b,link);229. deleteb;230. 231. 232. 233. 234. /*235. HelperFunctions236. */237. 238. double239. AODV:PerHopTime(aodv_rt_entry*rt)240. intnum_non_zero=0,i;241. doubletotal_latency=0.0;242. 243. if(!rt)244. return(double)NODE_TRAVERSAL_TIME);245. 246. for(i=0;irt_disc_latencyi0.0)248. num_non_zero+;249. total_latency+=rt-rt_disc_latencyi;250. 251. 252. if(num_non_zero0)253. return(total_latency/(double)num_non_zero);254. else255. return(double)NODE_TRAVERSAL_TIME);256. 257. 258. 259. /*260. LinkFailureManagementFunctions261. */262. 263. staticvoid264. aodv_rt_failed_callback(Packet*p,void*arg)265. (AODV*)arg)-rt_ll_failed(p);266. 267. 268. /*269. *Thisroutineisinvokedwhenthelink-layerreportsaroutefailed.270. */271. /*邻居链路down掉，处理*/272. void273. AODV:rt_ll_failed(Packet*p)274. structhdr_cmn*ch=HDR_CMN(p);275. structhdr_ip*ih=HDR_IP(p);276. aodv_rt_entry*rt;277. nsaddr_tbroken_nbr=ch-next_hop_;/记录下一跳邻居的地址278. 279. #ifndefAODV_LINK_LAYER_DETECTION280. drop(p,DROP_RTR_MAC_CALLBACK);281. #else282. 283. /*284. *Non-datapacketsandBroadcastPacketscanbedropped.285. */286. /如果是非数据或者广播报文，则可以直接丢弃287. if(!DATA_PACKET(ch-ptype()|288. (u_int32_t)ih-daddr()=IP_BROADCAST)289. drop(p,DROP_RTR_MAC_CALLBACK);290. return;291. 292. log_link_broke(p);293. /如果不存在到达目的节点的路径，丢弃报文294. if(rt=rtable.rt_lookup(ih-daddr()=0)295. drop(p,DROP_RTR_MAC_CALLBACK);296. return;297. 298. log_link_del(ch-next_hop_);299. 300. #ifdefAODV_LOCAL_REPAIR301. /*ifthebrokenlinkisclosertothedestthansource,302. attemptalocalrepair.Otherwise,bringdowntheroute.*/303. 304. /如果转发的跳数大于到达目的节点的跳数，则进行路由修复；否则丢弃通过此邻居的305. /数据并且删除此邻居306. if(ch-num_forwards()rt-rt_hops)307. local_rt_repair(rt,p);/localrepair308. /retrieveallthepacketsintheifqusingthislink,309. /queuethepacketsforwhichlocalrepairisdone,310. return;311. 312. else313. #endif/LOCALREPAIR314. 315. 316. drop(p,DROP_RTR_MAC_CALLBACK);317. /Dothesamethingforotherpacketsintheinterfacequeueusingthe318. /brokenlink-Mahesh319. while(p=ifqueue-filter(broken_nbr)320. drop(p,DROP_RTR_MAC_CALLBACK);321. 322. nb_delete(broken_nbr);323. 324. 325. #endif/LINKLAYERDETECTION326. 327. /*当发现邻居失效的时候，就会调用此函数*/328. void329. AODV:handle_link_failure(nsaddr_tid)330. aodv_rt_entry*rt,*rtn;331. Packet*rerr=Packet:alloc();332. structhdr_aodv_error*re=HDR_AODV_ERROR(rerr);333. 334. re-DestCount=0;335. /查找通过此邻居节点到达目的的路由，336. for(rt=rtable.head();rt;rt=rtn)/foreachrtentry337. rtn=rt-rt_link.le_next;338. /如果跳数不是无限大并且下一跳就是失效的邻居339. if(rt-rt_hops!=INFINITY2)&(rt-rt_nexthop=id)340. assert(rt-rt_flags=RTF_UP);341. assert(rt-rt_seqno%2)=0);342. rt-rt_seqno+;343. re-unreachable_dstre-DestCount=rt-rt_dst;344. re-unreachable_dst_seqnore-DestCount=rt-rt_seqno;345. #ifdefDEBUG346. fprintf(stderr,%s(%f):%dt(%dt%ut%d)n,_FUNCTION_,CURRENT_TIME,347. index,re-unreachable_dstre-DestCount,348. re-unreachable_dst_seqnore-DestCount,rt-rt_nexthop);349. #endif/DEBUG350. re-DestCount+=1;351. rt_down(rt);/将此路由down掉352. 353. /removethelostneighborfromalltheprecursorlists354. rt-pc_delete(id);/删除此路由的前缀列表355. 356. /*如果存在通过此邻居到达目的节点的路由，则发送错误报文*/357. if(re-DestCount0)358. #ifdefDEBUG359. fprintf(stderr,%s(%f):%dtsendingRERR.n,_FUNCTION_,CURRENT_TIME,index);360. #endif/DEBUG361. sendError(rerr,false);362. 363. else364. Packet:free(rerr);365. 366. 367. 368. void369. AODV:local_rt_repair(aodv_rt_entry*rt,Packet*p)370. #ifdefDEBUG371. fprintf(stderr,%s:Dst-%dn,_FUNCTION_,rt-rt_dst);372. #endif373. /Bufferthepacket374. rqueue.enque(p);375. 376. /marktherouteasunderrepair377. rt-rt_flags=RTF_IN_REPAIR;378. 379. sendRequest(rt-rt_dst);380. 381. /setupatimerinterrupt382. Scheduler:instance().schedule(&lrtimer,p-copy(),rt-rt_req_timeout);383. 384. /*更新路由条目*/385. void386. AODV:rt_update(aodv_rt_entry*rt,u_int32_tseqnum,u_int16_tmetric,387. nsaddr_tnexthop,doubleexpire_time)388. 389. rt-rt_seqno=seqnum;390. rt-rt_hops=metric;391. rt-rt_flags=RTF_UP;392. rt-rt_nexthop=nexthop;393. rt-rt_expire=expire_time;394. 395. /*将此路由条目down掉*/396. void397. AODV:rt_down(aodv_rt_entry*rt)398. /*399. *Makesurethatyoudontdownaroutemorethanonce.400. */401. 402. if(rt-rt_flags=RTF_DOWN)403. return;404. 405. 406. /assert(rt-rt_seqno%2);/istheseqnoodd?407. rt-rt_last_hop_count=rt-rt_hops;408. rt-rt_hops=INFINITY2;409. rt-rt_flags=RTF_DOWN;410. rt-rt_nexthop=0;411. rt-rt_expire=0;412. 413. /*rt_downfunction*/414. 415. /*416. RouteHandlingFunctions417. */418. 419. void420. AODV:rt_resolve(Packet*p)421. structhdr_cmn*ch=HDR_CMN(p);422. structhdr_ip*ih=HDR_IP(p);423. aodv_rt_entry*rt;424. 425. /*426. *Setthetransmitfailurecallback.That427. *wontchange.428. */429. /这是一个指针，具体请看另一篇博客430. ch-xmit_failure_=aodv_rt_failed_callback;431. ch-xmit_failure_data_=(void*)this;432. rt=rtable.rt_lookup(ih-daddr();433. if(rt=0)434. rt=rtable.rt_add(ih-daddr();435. 436. 437. /*438. *Iftherouteisup,forwardthepacket439. */440. /如果存在路由，则转发441. if(rt-rt_flags=RTF_UP)442. assert(rt-rt_hops!=INFINITY2);443. forward(rt,p,NO_DELAY);444. 445. /*446. *ifIamthesourceofthepacket,thendoaRouteRequest.447. */448. elseif(ih-saddr()=index)449. /450. /如果是源节点且没有到达目的节点的路由，缓存数分组451. /发送路由请求452. rqueue.enque(p);453. sendRequest(rt-rt_dst);454. 455. /*456. *Alocalrepairisinprogress.Bufferthepacket.457. */458. /如果此路由处于修复状态，则缓存分组459. elseif(rt-rt_flags=RTF_IN_REPAIR)460. rqueue.enque(p);461. 462. 463. /*464. *Iamtryingtoforwardapacketforsomeoneelsetowhich465. *Idonthavearoute.466. */467. /否则发送错误报文468. else469. Packet*rerr=Packet:alloc();470. structhdr_aodv_error*re=HDR_AODV_ERROR(rerr);471. /*472. *Fornow,dropthepacketandsenderrorupstream.473. *Nowtherouteerrorsarebroadcasttoupstream474. *neighbors-Mahesh09/11/99475. */476. 477. assert(rt-rt_flags=RTF_DOWN);478. re-DestCount=0;479. re-unreachable_dstre-DestCount=rt-rt_dst;480. re-unreachable_dst_seqnore-DestCount=rt-rt_seqno;481. re-DestCount+=1;482. #ifdefDEBUG483. fprintf(stderr,%s:sendingRERR.n,_FUNCTION_);484. #endif485. sendError(rerr,false);486. 487. drop(p,DROP_RTR_NO_ROUTE);488. 489. 490. 491. /*定时查看路由缓存条目*/492. void493. AODV:rt_purge()494. aodv_rt_entry*rt,*rtn;495. doublenow=CURRENT_TIME;496. doubledelay=0.0;497. Packet*p;498. 499. for(rt=rtable.head();rt;rt=rtn)/foreachrtentry500. rtn=rt-rt_link.le_next;501. /如果此路由条目标注为有效，但是生存时间为0502. /丢弃前往目的分组，并且将此路由条目down掉503. if(rt-rt_flags=RTF_UP)&(rt-rt_expirert_hops!=INFINITY2);507. while(p=rqueue.deque(rt-rt_dst)508. #ifdefDEBUG509. fprintf(stderr,%s:callingdrop()n,510. _FUNCTION_);511. #endif/DEBUG512. drop(p,DROP_RTR_NO_ROUTE);513. 514. rt-rt_seqno+;515. assert(rt-rt_seqno%2);516. rt_down(rt);517. 518. /如果此路由条目并没有过期，则可以发送分组519. elseif(rt-rt_flags=RTF_UP)520. /Iftherouteisnotexpired,521. /andtherearepacketsinthesendbufferwaiting,522. /forwardthem.Thisshouldnotbeneeded,butthisextra523. /checkdoesnoharm.524. assert(rt-rt_hops!=INFINITY2);525. while(p=rqueue.deque(rt-rt_dst)526. forward(rt,p,delay);527. delay+=ARP_DELAY;528. 529. 530. /如果此路由条目已经down掉，但是有前往目的的分组，则发送路由请求531. elseif(rqueue.find(rt-rt_dst)532. /Iftherouteisdownand533. /ifthereisapacketforthisdestinationwaitingin534. /thesendbuffer,thensendoutrouterequest.sendRequest535. /willcheckwhetheritistimetoreallysendoutrequest536. /ornot.537. /Thismaynotbecrucialtodoithere,aseachgenerated538. /packetwilldoasendRequestanyway.539. 540. sendRequest(rt-rt_dst);541. 542. 543. 544. 545. /*546. PacketReceptionRoutines547. */548. 549. void550. AODV:recv(Packet*p,Handler*)551. structhdr_cmn*ch=HDR_CMN(p);552. structhdr_ip*ih=HDR_IP(p);553. 554. assert(initialized();555. /assert(p-incoming=0);556. /XXXXXNOTE:useofincomingflaghasbeendepracated;Inordertotrackdirectionofpktflow,direction_inhdr_cmnisusedinstead.seepacket.hfordetails.557. /如果分组类型是AODV类型，则交给recvAodv函数558. if(ch-ptype()=PT_AODV)559. ih-ttl_-=1;560. recvAODV(p);561. return;562.