In this program, you will learn how to connect Client-Server and sent messages from Client to Server.
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| Socket Programming |
UDP Server Client implementation in C / Socket Programming:
udpserver.c
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<netdb.h>
#include<stdio.h>
#include<unistd.h>
#include<string.h>
#include<stdlib.h>
#define LOCAL_SERVER_PORT 1500
#define MAX_MSG 100
int main(int argc,char *argv[]) {
int sd, rc, n, cliLen,num[2],i;
long int tot;
struct sockaddr_in cliAddr, servAddr;
char msg[MAX_MSG],name[MAX_MSG]="Ms,";
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);
for(i=0;i<2;i++)
{
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);
strcat(name,msg);
}
printf("the name is : %s\n",name);
return 0;
}
udpclient.c
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<netdb.h>
#include<stdio.h>
#include<unistd.h>
#include<string.h>
#include<stdlib.h>
#include<sys/time.h>
#define REMOTE_SERVER_PORT 1500
#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 <server> <data1><data2> \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 in_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: cannont 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);
if(rc<0) {
printf("%s: cannort bind port\n", argv[0]);
exit(1);
}
for(i=2;i<argc;i++)
rc=sendto(sd, argv[i], strlen(argv[i])+1,0,(struct sockaddr *) &remoteServAddr,sizeof(remoteServAddr));
if(rc<0) {
printf("%s: cannnot send data %d \n",argv[0],i-1);
close(sd);
exit(1);
}
return 1;
}
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