IMPLEMENTATION OF UDP ( Universal Datagram Protocol ) Programs

IMPLEMENTATION OF UDP
PROGRAM:

CLIENT:

#include
#include
#include
#include
#include
#include
#include
#include
#include
#define REMOTE_SERVER_PORT 1896s
#define MAX_MSG 100
int main(int argc,char*argv[])
{
int sd,rc,i;
struct sockaddr_in cliaddr,remoteservaddr;
struct hostent *h;
if(argc<3)
{
printf("Usage:%s..\n",argv[0]);
exit(1);
}
h=gethostbyname(argv[1]);
if(h==NULL)
{
printf("%s:unknown host%s\n",argv[0],argv[1]);
exit(1);
}
printf("%s:sending data to '%s'(IP:%s)\n",argv[0],h->h_name,inet_ntoa(*(struct i
n_addr*)h->h_addr_list[0]));
remoteservaddr.sin_family=h->h_addrtype;
memcpy((char*)&remoteservaddr.sin_addr.s_addr,h->h_addr_list[0],h->h_length);
remoteservaddr.sin_port=htons(REMOTE_SERVER_PORT);
sd=socket(AF_INET,SOCK_DGRAM,0);
if(sd<0)
{
printf("%s:cannot open socket\n",argv[0]);
exit(1);
}
cliaddr.sin_family=AF_INET;
cliaddr.sin_addr.s_addr=htonl(INADDR_ANY);
cliaddr.sin_port=htons(0);
rc=bind(sd,(struct sockaddr*)&cliaddr,sizeof(cliaddr));
if(rc<0)
{
printf("%s:cannot bindport\n",argv[0]);
exit(1);
}
for(i=2;i{
rc=sendto(sd,argv[i],strlen(argv[i])+1,0,(struct sockaddr*)&remoteservaddr,sizeo
f(remoteservaddr));
if(rc<0)
{
printf("%s:cannot send data%d\n",argv[0],i-1);
close(sd);
exit(1);
}
}
return 1;
}


SERVER:

#include
#include
#include
#include
#include
#include
#include
#define LOCAL_SERVER_PORT 1896
#define MAX_MSG 100
int main(int argc,char *argv[])
{
int sd,rc,n,clilen;
struct sockaddr_in cliaddr,servaddr;
char msg[MAX_MSG];
sd=socket(AF_INET,SOCK_DGRAM,0);
if(sd<0)
{
printf("%s:cannot open socket\n",argv[0]);
exit(1);
}
servaddr.sin_family=AF_INET;
servaddr.sin_addr.s_addr=htonl(INADDR_ANY);
servaddr.sin_port=htons(LOCAL_SERVER_PORT);
rc=bind(sd,(struct sockaddr*)&servaddr,sizeof(servaddr));
if(rc<0)
{
printf("%s:cannot bind port number %d\n",argv[0],LOCAL_SERVER_PORT);
exit(1);
}
printf("%s:waiting for data on port UDP%u\n",argv[0],LOCAL_SERVER_PORT);
while(1)
{
memset(msg,0x0,MAX_MSG);
clilen=sizeof(cliaddr);
n=recvfrom(sd,msg,MAX_MSG,0,(struct sockaddr*)&cliaddr,&clilen);
if(n<0)
{
printf("%s:cannot receive data\n",argv[0]);
continue;
}
printf("%s:from%s:UDP%u:%s\n",argv[0],inet_ntoa(cliaddr.sin_addr),ntohs(cliaddr.
sin_port),msg);
}
return 0;
}
























OUTPUT:

IN SERVER:

[testciet @linuxcentre ~]$ ./a.out
./a.out:waiting for data on port UDP1896
./a.out:from127.0.0.1:UDP32771:hi ……


IN CLIENT:

[testciet@linuxcentre ~]$ ./a.out localhost hi ……
./a.out:sending data to 'linuxcentre'(IP:127.0.0.1)



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