CRC #include<stdio.h>
#include<stdlib.h> #include<unistd.h> #include<string.h> #define N strlen(g) char t[120],cs[120],g[]="100000111"; int a,c,e; void xor() { for(c=1;c<N;c++) cs[c]=((cs[c]==g[c])?'0':'1'); } void crc()

{ for(e=0;e<N;e++) cs[e]=t[e]; do { if(cs[0]=='1') xor(); for(c=0;c<N-1;c++) cs[c]=cs[c+1]; cs[c]=t[e++]; } while(e<=a+N-1); } void main() { printf("enter the polynomial\n"); scanf("%s",t); printf("generating polynomial is %s\n",g); a=strlen(t); for(e=a;e<a+N-1;e++) t[e]='0'; printf("modified t[u] is %s\n",t); crc(); printf("checksum is :%s\n",cs); for(e=a;e<a+N-1;e++) t[e]=cs[e-a]; printf("final codeword is :%s\n",t); printf("test error detection 0(yes)1(no)?:\n"); scanf("%d",&e); if(e==0) { do { printf("enter position where error has to be inserted\n"); scanf("%d",&e); } while(e==0 || e>a+N-1); t[e-1]=(t[e-1]=='0')?'1':'0'; printf("errorneous data %s\n",t); }

crc();

for(e=0;(e<N-1)&&(cs[e]!='1');e++); if(e<N-1) printf("error detected\n"); else printf("error is not detected\n"); } TCP C #include<stdio.h> #include<stdlib.h> #include<unistd.h> #include<sys/socket.h> #include<sys/types.h> #include<arpa/inet.h> #include<netdb.h> #include<netinet/in.h> #include<errno.h> #include<string.h> int main() { int sock,bytes_recv; struct sockaddr_in server_addr; char recv_data[1024],send_data[1024]; struct hostent *host; host=gethostbyname("127.0.0.1"); if((sock=socket(AF_INET,SOCK_STREAM,0))==-1) { perror("socket"); exit(1); } server_addr.sin_family=AF_INET; server_addr.sin_port=htons(6119); server_addr.sin_addr.s_addr=inet_addr("127.0.0.1"); if(connect(sock,(struct sockaddr *)&server_addr,sizeof(struct sockaddr))==-1) { perror("connect"); exit(1); } printf("send Filename to send\n"); gets(send_data);

	if(strcmp(send_data,"q")!=0)
		send(sock,send_data,strlen(send_data),0);
	
	while((bytes_recv=recv(sock,recv_data,1024,0))>0)
	{
		recv_data[bytes_recv]='\0';
		//printf("%s\n\n", recv_data);
		//if(strcmp(recv_data,"q")==0)
	//	{
	//	close(sock);
	//	break;
	//	}
		printf("%s\n", recv_data);
	}
close(sock);	
return 0;

} TCP S #include<stdio.h> #include<stdlib.h> #include<arpa/inet.h> #include<sys/types.h> #include<sys/socket.h> #include<errno.h> #include<unistd.h> #include<netinet/in.h> #include<string.h> int main() { struct sockaddr_in server_addr; struct sockaddr_in client_addr; FILE *fptr; int sock,connected,bytes_recv; char ch,send_data[1024],recv_data[1024]; int sin_size,flag = 0;

if((sock=socket(AF_INET,SOCK_STREAM,0))==-1)
{
	perror("socket");
	exit(1);
}


server_addr.sin_family=AF_INET;
server_addr.sin_port=htons(6119);
server_addr.sin_addr.s_addr=inet_addr("127.0.0.1");

if(bind(sock,(struct sockaddr *)&server_addr, sizeof(struct sockaddr))==-1)
{
	perror("unable to bind");
	exit(1);
}

if(listen(sock,5)==-1)
{
	perror("lsten");
	exit(1);
}

printf("tcp server is waiting for client on port XXXX\n");
sin_size=sizeof(struct sockaddr_in);
connected=accept(sock,(struct sockaddr *)&client_addr,&sin_size);

while(1)
{
	
	bytes_recv=recv(connected,recv_data,1024,0);
	recv_data[bytes_recv]='\0';

	printf("reciecved data is %s\n\n\n",recv_data);
	
	
	fptr=fopen(recv_data,"r");
	if(fptr==NULL)
	{
		strcpy(send_data,"FILE");
		send(connected,send_data,strlen(send_data),0);
	}
	ch = fgetc(fptr);

	while(ch != EOF)//this loop searches the for the current word
	{
	   // fscanf(fptr,"%s",send_data);
		send_data[flag] = ch;
		flag++;
		ch = fgetc(fptr);
	   //send(connected,send_data,strlen(send_data),0);
	}
		send(connected,send_data,strlen(send_data),0);
		//send_data[0] = 'q';
		//strcpy(send_data,"q");
		//send(connected,send_data,strlen(send_data),0);
		close(connected);
		break;
}

} UDP C #include <stdio.h> #include <sys/socket.h> #include <netinet/in.h> #include <string.h>

int main(){ int clientSocket, portNum, nBytes; char buffer[1024]; struct sockaddr_in serverAddr; socklen_t addr_size;

/Create UDP socket/ clientSocket = socket(PF_INET, SOCK_DGRAM, 0);

/Configure settings in address struct/ serverAddr.sin_family = AF_INET; serverAddr.sin_port = htons(8893); serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1"); memset(serverAddr.sin_zero, '\0', sizeof serverAddr.sin_zero);

/Initialize size variable to be used later on/ addr_size = sizeof serverAddr;

while(1){ printf("Type a sentence to send to server:\n"); fgets(buffer,1024,stdin); printf("You typed: %s",buffer);

nBytes = strlen(buffer) + 1;

/*Send message to server*/
sendto(clientSocket,buffer,nBytes,0,(struct sockaddr *)&serverAddr,addr_size);

/*Receive message from server*/
            nBytes = recvfrom(clientSocket,buffer,1024,0,NULL, NULL);

printf("Received from server: %s\n",buffer);

}

return 0; } UDP S

#include <stdio.h> #include <sys/socket.h> #include <netinet/in.h> #include <string.h> #include <stdlib.h>

int main(){ int udpSocket, nBytes; char buffer[1024]; struct sockaddr_in serverAddr, clientAddr; struct sockaddr_storage serverStorage; socklen_t addr_size, client_addr_size; int i;

/Create UDP socket/ udpSocket = socket(PF_INET, SOCK_DGRAM, 0);

/Configure settings in address struct/ serverAddr.sin_family = AF_INET; serverAddr.sin_port = htons(8893); serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1"); memset(serverAddr.sin_zero, '\0', sizeof serverAddr.sin_zero);

/Bind socket with address struct/ bind(udpSocket, (struct sockaddr *) &serverAddr, sizeof(serverAddr));

/Initialize size variable to be used later on/ addr_size = sizeof serverStorage;

while(1){ /* Try to receive any incoming UDP datagram. Address and port of

•   requesting client will be stored on serverStorage variable */
  

  nBytes = recvfrom(udpSocket,buffer,1024,0,(struct sockaddr *)&serverStorage, &addr_size);

  /Convert message received to uppercase/ for(i=0;i<nBytes-1;i++) buffer[i] = toupper(buffer[i]);

  /Send uppercase message back to client, using serverStorage as the address/ sendto(udpSocket,buffer,nBytes,0,(struct sockaddr *)&serverStorage,addr_size); }

return 0; }

DVR

#include<stdio.h> struct node { unsigned dist[20]; unsigned from[20]; }rt[10]; int main() { int dmat[20][20]; int n,i,j,k,count=0; printf("\nEnter the number of nodes: "); scanf("%d",&n); printf("\nEnter the cost matrix\n"); for(i=0;i<n;i++) for(j=0;j<n;j++) { scanf("%d",&dmat[i][j]); dmat[i][i]=0; rt[i].dist[j]=dmat[i][j]; rt[i].from[j]=j; } do { count=0; for(i=0;i<n;i++) { for(j=0;j<n;j++) { for(k=0;k<n;k++) { if(rt[i].dist[j]>dmat[i][k]+rt[k].dist[j]) { rt[i].dist[j]=rt[i].dist[k]+rt[k].dist[j]; rt[i].from[j]=k; count++; } } } } }while(count!=0); for(i=0;i<n;i++) { printf("\n\nState value for router %d is \n",i+1); printf("\nNode \t Via \t Dist. "); for(j=0;j<n;j++) { printf("\n%d \t %d \t %d ",j+1,rt[i].from[j]+1,rt[i].dist[j]); } } printf("\n\n"); }

LE #include<stdio.h> #include<stdlib.h> #define MIN(x,y) (x>y)?y:x int main() { int orate,drop=0,cap,x,count=0,inp[10]={0},i=0,nsec,ch; printf("\n enter bucket size : "); scanf("%d",&cap); printf("\n enter output rate :"); scanf("%d",&orate); do{ printf("\n enter number of packets coming at second %d :",i+1); scanf("%d",&inp[i]); if(inp[i]>cap) { printf("Bucket overflow\n"); printf("Packet Discarded\n"); exit(0); } i++; printf("\n enter 1 to contiue or 0 to quit.........."); scanf("%d",&ch); } while(ch); nsec=i; printf("\n Second \t Recieved \t Sent \t Dropped \tRemained \n"); for(i=0;count || i<nsec;i++) { printf(" %d",i+1); printf(" \t\t%d\t ",inp[i]); printf(" \t%d\t ",MIN((inp[i]+count),orate)); if((x=inp[i]+count-orate)>0) { if(x>cap) { count=cap; drop=x-cap; } else { count=x; drop=0; } } else { drop=0; count=0; } printf(" \t %d\t %d \n",drop,count); } return 0; }