作者：冰蓝沸点
2007年05月21日 星期一 16:50DVSim.cpp:/****************************************************************** DVsim.c Distance Vector Routing Simulation Package** Event driven simulation of distributed, asynchronous, * distance vector routing. This file contains the network* simulation code which emulates layer 2 and below: ** - simulates packet tranmissions between two * physically connected nodes** - assumes with no packet loss or corruption** - calls initializations routines rtinit0, etc., before* beginning simulation*** Original code from Kurose and Ross, Computer Networking** Modified by S. Dykes Apr. 2000* 1. Changed RNG to use drand48() with seed = getpid()* 2. Replaced 999 with INF * 3. created common include file DVsim.h* 4. extended to 6 node network **---------------------------------------------------------------*/#define DVSIM_H#include "DVsim.h"#define FROM_LAYER2 2#define LINK_CHANGE 10extern int rpc0;extern int rpc1;extern int rpc2;extern int rpc3;extern int rpc4;extern int spc0;extern int spc1;extern int spc2;extern int spc3;extern int spc4;/*----------------------------------------* Event list and possible events*---------------------------------------*/struct event { double evtime; /* event time */ int evtype; /* event type code */ int eventity; /* entity where event occurs */ struct rtpkt *rtpktptr; /* ptr to packet (if any) assoc w/ this event */ struct event *prev; struct event *next;};struct event *evlist = NULL; /*--------------------------------* Simulation clock*-------------------------------*/double clocktime = 0.000;double get_clock() { return clocktime; }/*--------------------------------* Function prototypes*-------------------------------*/void init();void insertevent (struct event *);void printevlist();void tolayer2 (struct rtpkt );/*-------------------------------* MAIN*-------------------------------*/int main(){ struct event *eventptr; int i; /*---------------------------------------- * Loop until we run out of events *---------------------------------------*/ init(); printdt_0(&dt[0]); printdt_1(&dt[1]); printdt_2(&dt[2]); printdt_3(&dt[3]); printdt_4(&dt[4]); while (1) { /*---------------------------------------- * Get next event from top of list * Done if event list is empty *---------------------------------------*/ if (! (eventptr = evlist) ) break; evlist = evlist->next; if (evlist) evlist->prev=NULL; /*---------------------------------------- * Trace info *---------------------------------------*/ if (TRACE>1) { printf("/nMAIN: rcv event, t=%.3f, at %d", eventptr->evtime, eventptr->eventity); if (eventptr->evtype == FROM_LAYER2 ) { printf(" src:-,", eventptr->rtpktptr->sourceid); printf(" dest:-,", eventptr->rtpktptr->destid); printf(" contents: "); for (i=0; i<NODES; i++) printf ("= ",eventptr->rtpktptr->mincost[i]); printf("/n"); } } /*---------------------------------------- * Update clock to next event time *---------------------------------------*/ clocktime = eventptr->evtime; /*---------------------------------------- * Call event handler *---------------------------------------*/ if (eventptr->evtype == FROM_LAYER2 ) { if (eventptr->eventity == 0) {rtupdate0(eventptr->rtpktptr);printdt_0(&dt[0]);} else if (eventptr->eventity == 1) {rtupdate1(eventptr->rtpktptr);printdt_1(&dt[1]);} else if (eventptr->eventity == 2) {rtupdate2(eventptr->rtpktptr);printdt_2(&dt[2]);} else if (eventptr->eventity == 3) {rtupdate3(eventptr->rtpktptr);printdt_3(&dt[3]);} else if (eventptr->eventity == 4) {rtupdate4(eventptr->rtpktptr);printdt_4(&dt[4]);} else { printf("Panic: unknown event entity/n"); exit(0); } } else if (eventptr->evtype == LINK_CHANGE ) { if (clocktime < 10001.0) { linkhandler0(1,20); linkhandler1(0,20); } else { linkhandler0(1,1); linkhandler1(0,1); } } else { printf("Panic: unknown event type/n"); exit(0); } /*-------------------------------------------------------- * Free memory for packet (if any) and event struct *-------------------------------------------------------*/ if (eventptr->evtype == FROM_LAYER2 ) free(eventptr->rtpktptr); free(eventptr); } /*------------------------------- * SIMULATION TERMINATED *-------------------------------*/ printf("/nSimulator terminated at t=%f, no packets in medium/n", clocktime); cout << "Node0 total sended " << spc0 << " packets and received " << rpc0 << " packets." << endl; cout << "Node1 total sended " << spc1 << " packets and received " << rpc1 << " packets." << endl; cout << "Node2 total sended " << spc2 << " packets and received " << rpc2 << " packets." << endl; cout << "Node3 total sended " << spc3 << " packets and received " << rpc3 << " packets." << endl; cout << "Node4 total sended " << spc4 << " packets and received " << rpc4 << " packets." << endl; return 0;}/*-------------------------------* init*-------------------------------*/void init() { int i; double sum, avg; struct event *evptr; /*--------------------- * Input TRACE *--------------------*/ printf ("Enter value for TRACE (no trace =0, user= 1 or 2, developer= 3): "); scanf ("%d", &TRACE); /*--------------------- * Test RNG *--------------------*/ srand ((unsigned) getpid()); for (i = 0, sum = 0.; i < 1000; i++) sum += rand(); avg = (sum / 1000.0 - 15000) / 2000; if (avg < 0.25 || avg > 0.75) { printf("RNG PROBLEM/n"); printf("Average of 1000 random numbers is %g (expected 0.5)./n", avg); printf("It is likely that random number generation on your machine/n"); printf("is different from what this emulator expects. Please take/n"); printf("a look at the routine init() in the emulator code. /n"); exit(0); } /*------------------------------------- * Initialize clock and nodes *------------------------------------*/ clocktime = 0.0; rtinit0(); rtinit1(); rtinit2(); rtinit3(); rtinit4(); /*------------------------------------- * Initialize future link changes *------------------------------------*/ if (LINKCHANGES == 1) { evptr = (struct event *)malloc(sizeof(struct event)); evptr->evtime = 10000.0; evptr->evtype = LINK_CHANGE; evptr->eventity = -1; evptr->rtpktptr = NULL; insertevent(evptr); evptr = (struct event *)malloc(sizeof(struct event)); evptr->evtype = LINK_CHANGE; evptr->evtime = 20000.0; evptr->rtpktptr = NULL; insertevent(evptr); }}/********************* EVENT HANDLING ROUTINES ********* These routines handle the event list ******************************************************//*------------------------------------------------------------* insertevent** Inserts object in event list. List is sorted by time.* p -> object to be inserted * q -> top of list *------------------------------------------------------------*/void insertevent (struct event *p){ struct event *q,*qold; if (TRACE>3) { printf(" INSERTEVENT: time is %lf/n",clocktime); printf(" INSERTEVENT: future time will be %lf/n",p->evtime); } q = evlist; if (q==NULL) { /*-------------------------------- * Empty list - insert at top *-------------------------------*/ evlist=p; p->next=NULL; p->prev=NULL; } else { /*---------------------------------------- * Find event time > p's time *---------------------------------------*/ for (qold=q; q !=NULL && p->evtime > q->evtime; q=q->next) qold=q; if (q==NULL) { /*--------------------- * End of list *--------------------*/ qold->next = p; p->prev = qold; p->next = NULL; } else if (q==evlist) { /*--------------------- * Top of list *---------------------*/ p->next=evlist; p->prev=NULL; p->next->prev=p; evlist = p; } else { /*--------------------- * Middle of list *---------------------*/ p->next=q; p->prev=q->prev; q->prev->next=p; q->prev=p; } }}/*------------------------------------------------------------* printevlist - prints event list*------------------------------------------------------------*/void printevlist(){ struct event *q; printf("--------------/nEvent List Follows:/n"); for (q = evlist; q!=NULL; q=q->next) printf("Event time: %f, type: %d entity: %d/n",q->evtime,q->evtype,q->eventity); printf("--------------/n");}/*------------------------------------------------------------* tolayer2 *------------------------------------------------------------*/void tolayer2 (struct rtpkt packet){ struct rtpkt *mypktptr; struct event *evptr, *q; double lastime; int i;/*-------------------------------------------------------------------------* Check for packet errors* Check if source and destination id's are reasonable *-------------------------------------------------------------------------*/ if (packet.sourceid<0 || packet.sourceid >NODES) { printf("WARNING: illegal source id in your packet, ignoring packet!/n"); return; } if (packet.destid<0 || packet.destid >NODES) { printf("WARNING: illegal dest id in your packet, ignoring packet!/n"); return; } if (packet.sourceid == packet.destid) { printf("WARNING: source and destination id's the same, ignoring packet!/n"); return; } if (linkcost[packet.sourceid][packet.destid] == INF) { printf("WARNING: source and destination not connected, ignoring packet!/n"); return; }/*-------------------------------------------------------------------------* Make a copy of the packet student just gave me since he/she may decide* to do something with the packet after we return back to him/her. *-------------------------------------------------------------------------*/mypktptr = (struct rtpkt *) malloc(sizeof(struct rtpkt));mypktptr->sourceid = packet.sourceid;mypktptr->destid = packet.destid;for (i=0; i<NODES; i++) mypktptr->mincost[i] = packet.mincost[i];/*---------------------* Print trace info *--------------------*/if (TRACE>2) { printf(" TOLAYER2: source: %d, dest: %d/n costs:", mypktptr->sourceid, mypktptr->destid); for (i=0; i<4; i++) printf("%d ",mypktptr->mincost[i]); printf("/n");}/*-----------------------------------------------------------------* Create future event for arrival of packet at the other side*-----------------------------------------------------------------*/evptr = (struct event *)malloc(sizeof(struct event));evptr->evtype = FROM_LAYER2; /* packet will pop out from layer3 */evptr->eventity = packet.destid; /* event occurs at other entity */evptr->rtpktptr = mypktptr; /* save ptr to my copy of packet *//*-----------------------------------------------------------------* Compute the arrival time of packet at the other end.* Medium can not reorder, so make sure packet arrives between 1 and 10* time units after the latest arrival time of packets* currently in the medium on their way to the destination *-----------------------------------------------------------------*/lastime = clocktime;for (q=evlist; q!=NULL ; q = q->next) { if ( (q->evtype==FROM_LAYER2 && q->eventity==evptr->eventity) ) lastime = q->evtime;}evptr->evtime = lastime + 2. * rand();/*------------------* Trace info *-----------------*/if (TRACE>2) printf(" TOLAYER2: scheduling arrival on other side/n");/*---------------------------------------------------* Insert message arrival into event list*--------------------------------------------------*/insertevent(evptr);}
