UDP client doesn't connect with server - linux

Question

I create chat with clients and server. But the client can't connect to the server. Please tell me what is wrong?
Server code
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#define BUFOR 512
int main(int argc, char *argv[])
{
int fd, serverLength, cLength;
struct sockaddr_in serverAddr, c_addr[2], clientAddr;
cLength = sizeof(clientAddr);
char buf[BUFOR];
int clients = 0;
int c_port[2];
if(argc != 2)
{
printf(" portu");
exit(1);
}
uint16_t port = atoi( argv[ 1 ] );
if ((fd = socket(AF_INET, SOCK_DGRAM, 0))==-1)
{
perror("Blad socket");
exit(1);
}
bzero((char*) &serverAddr, sizeof(serverAddr));
serverAddr.sin_family = AF_INET;
serverAddr.sin_addr.s_addr = htonl(INADDR_ANY);
serverAddr.sin_port = htons(port);
serverLength = sizeof(serverAddr);
if (bind(fd, (struct sockaddr* ) &serverAddr, serverLength)==-1)
{
perror("Blad bind");
exit(1);
}
for(;;)
{
printf("Receiving...\n");
if (recvfrom(fd, buf, BUFOR, 0, (struct sockaddr*)&clientAddr, &cLength)==-1)
{
perror("Blad recvfrom");
exit(1);
}
if (clients==0)
{
c_addr[0] = clientAddr;
c_port[0] = ntohs(c_addr[0].sin_port);
clients++;
printf("Client 0 was connected. Port: %d\n",c_port[0]);
sendto(fd, "I am only one cleint.", 24, 0, (struct sockaddr*)&clientAddr, cLength);
}else if(clients==1)
{
if (c_port[0]==ntohs(clientAddr.sin_port))
{
sendto(fd, "I am only one client.", 24, 0, (struct sockaddr*)&c_addr[0], sizeof(c_addr[0]));
printf("One cleint\n");
}else
{
c_addr[1] = clientAddr;
c_port[1] = ntohs(c_addr[1].sin_port);
clients++;
printf("Second cleint\n");
sendto(fd, buf, BUFOR, 0, (struct sockaddr*)&c_addr[0], sizeof(c_addr[0]));
}
}else
{
if (c_port[0]==ntohs(clientAddr.sin_port))
{
printf("Sending emssage for client 1\n");
if (sendto(fd, buf, BUFOR, 0, (struct sockaddr*)&c_addr[1], sizeof(c_addr[0]))==-1)
{
clients--;
perror("Error senttoen");
}
}else
{
printf("Sending message for client 0\n");
if (sendto(fd, buf, BUFOR, 0, (struct sockaddr*)&c_addr[0], sizeof(c_addr[1]))==-1)
{
clients--;
perror("Blad senttoen");
}
}
}
}
close(fd);
return 0;
}
Client code
#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <signal.h>
#define BUFLEN 512
int main(int argc, char *argv[])
{
struct sockaddr_in serv_addr;
int sockfd;
socklen_t slen;
slen=sizeof(serv_addr);
char buf[BUFLEN];
if(argc != 3)
{
printf("Usage : %s <Server-IP>\n",argv[2]);
exit(0);
}
if ((sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP))==-1)
{
perror("Socket Error");
exit(1);
}
uint16_t port = atoi( argv[ 1 ] );
bzero(&serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(port);
serv_addr.sin_addr.s_addr = inet_addr(argv[2]);
while(1)
{
bzero(buf,BUFLEN);
printf("Attempting to READ to socket %d: ",sockfd);
fflush(stdout);
if(recvfrom(sockfd, buf, BUFLEN, 0, (struct sockaddr*)&serv_addr, &slen)==-1)
{
perror("Blad bind");
exit(1);
}
printf("The message from the server is: %s \n",buf);
printf("Please enter the message to send: ");
bzero(buf,BUFLEN);
fgets(buf,BUFLEN,stdin);
printf("Attempting to write to socket %d: ",sockfd);
fflush(stdout);
if (sendto(sockfd, buf, BUFLEN, 0, (struct sockaddr*)&serv_addr, slen)==-1)
{
perror("Blad bind");
exit(1);
}
}
close(sockfd);
return 0;
}
It seems the sendto is blocked by recvfrom, but I don't know how to create it in infinitable loop.