Programming

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <netinet/in.h>
#include <sys/wait.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <arpa/inet.h>
void sigchld_handler(int s)
{
while(waitpid(-1,NULL,WNOHANG)>0);
}
void *get_in_addr(struct sockaddr *sa)
{
if(sa->sa_family==AF_INET)
{
return &(((struct sockaddr_in *)sa)->sin_addr);
}
return &(((struct sockaddr_in6*)sa)->sin6_addr);
}
char pass[100];
char pass1[100];

int main()
{
int sockfd,new_fd,numbytes;
struct addrinfo hints,*servinfo,*p;
struct sockaddr_storage their_addr;
socklen_t sin_size;
socklen_t *size;
struct sockaddr *names;
int yes=1,len=0;
struct sigaction sa;
char s[INET6_ADDRSTRLEN],s1[INET6_ADDRSTRLEN];
char name[20];
int rv;
memset(&hints,0,sizeof hints);
hints.ai_family=AF_UNSPEC;
hints.ai_socktype=SOCK_STREAM;
hints.ai_flags=AI_PASSIVE;
if((rv=getaddrinfo(NULL,"2001",&hints,&servinfo))==-1)
{
fprintf(stderr,"getaddrinfo:%s",gai_strerror(rv));
return 1;
}
printf("\n \n getaddrinfo:%d",rv);
printf("\n------------------------------");
for(p=servinfo;p!=NULL;p=p->ai_next)
{

if((sockfd=socket(p->ai_family,p->ai_socktype,p->ai_protocol))==-1)
{
perror("server:socket");
continue;
}
printf("\n server socket launched...");

if(setsockopt(sockfd,SOL_SOCKET,SO_BROADCAST,&yes,sizeof(int))==-1)
{
perror("setsockopt");
return 0;
}
printf("\n server setsocket option ...");

if(bind(sockfd,p->ai_addr,p->ai_addrlen)==-1)
{

close(sockfd);
perror("server:bind");
continue;
}
printf("\n socket binded....");
break;
}


if(p==NULL)
{
fprintf(stderr,"server:failed");
return 2;
}
if(listen(sockfd,10)==-1)
{
perror("listen");
return 0;
}
sa.sa_handler=sigchld_handler;
sa.sa_flags=SA_RESTART;
if(sigaction(SIGCHLD,&sa,NULL)==-1)
{
perror("sigaction");
exit(0);
}
printf("\n\nlisten to socket :%d",sockfd);

while(1)
{
sin_size=sizeof their_addr;
new_fd=accept(sockfd,(struct sockaddr *)&their_addr,&sin_size);
printf("\n sockfd=%d new_fd=%d",sockfd,new_fd);
if(new_fd==-1)
{
perror("accept");
continue;
}
if((rv=getpeername(new_fd,names,&sin_size))==-1)
    perror("r");
inet_ntop(their_addr.ss_family,names,s1,sizeof s1);
printf("\n Peer name:%s",s);
inet_ntop(their_addr.ss_family,get_in_addr((struct sockaddr *)&their_addr),s,sizeof s);
printf("\n\nserver:connected %s",s);
if(!fork())
{
while(1)
{
//printf("\n enter the text to the client:");
//gets(pass);
len=strlen("CAN_U");
if((send(new_fd,"CAN_U",len+1,0))==-1)
perror("error");
if((strcmp(pass,"bye"))==0)
    {
    close(new_fd);
    break;}
pass[0]='\0';
if(recv(new_fd,name,sizeof name,0)==-1)
perror("error");
if((strcmp("CAN_U",name))==0)
{
     if(send(sockfd,"YES",strlen("YES"),0)==-1)
        perror("error5");
    printf("\nSuccess") ;


}

}
close(new_fd);

}
close(new_fd);
}
return 0;
}