void dg_cli(int sockfd, struct sockaddr_in* servcaddr, int servlen)
{
char recvline[MAXLINE], sendline[MAXLINE], addr[MAXLINE];
int n, port;
if (inet_ntop(AF_INET, &servcaddr -> sin_addr.s_addr, addr, MAXLINE) == NULL)
{
perror("inet_ntop error");
exit(1);
}
port = ntohs(servcaddr -> sin_port);
while (fgets(recvline, MAXLINE, stdin) != NULL)
{
if ((n = sendto(sockfd, recvline, strlen(recvline), 0, (struct sockaddr*)servcaddr, servlen)) < 0)
{
perror("sendto error");
exit(1);
}
if ((n = readable_timeout(sockfd, 5)) == 0)
{
fprintf(stderr, "socket recvfrom timeout\n");
exit(1);
}
else
{
n = recvfrom(sockfd, recvline, MAXLINE, 0, NULL, NULL);
recvline[n] = '\0';
printf("%s", recvline);
}
}
}
/* check readable when timeout in seconds usec */
int readable_timeout_sec( int fd, int sec) {
return readable_timeout( fd, sec, 0 );
}
/* check readable when timeout in mircoseconds usec */
int readable_timeout_millisec( int fd, int millisec) {
return readable_timeout( fd, 0, millisec * 1000 );
}
/* check readable when timeout in mircoseconds usec */
int readable_timeout_usec( int fd, int usec) {
return readable_timeout( fd, 0, usec );
}
void dg_cli(int sockfd, const struct sockaddr *pservaddr, socklen_t servlen) {
int n,connection_sockfd,attempt_count,success_flag;
char sendline[MAXLINE], recvline[MAXLINE + 1];
struct sockaddr_in servaddr;
//Bind and print client socket addr.
cliaddr.sin_addr.s_addr = htonl(cliaddr.sin_addr.s_addr);
printf("\nClient will use: %s\n",inet_ntoa(cliaddr.sin_addr));
cliaddr.sin_family = AF_INET;
cliaddr.sin_port = htons(0);
if (bind(sockfd, (struct sockaddr *) &cliaddr,sizeof(cliaddr)))
err_sys_p("Coudlnt bind socket.");
printf("[INFO] Bounded to %s\n", (char*)Sock_ntop((struct sockaddr * ) &cliaddr,sizeof(cliaddr)));
//Connect to well known port of the server
if (connect(sockfd, (struct sockaddr *) pservaddr, servlen) < 0) {
err_sys_p("Connect error");
}
//Send the filename as datagram
int len = strlen(required_file_name);
if (write(sockfd, required_file_name, len) != len) {
err_sys_p("Write error.Server is unreachable");
}
success_flag=0;
for(attempt_count=0;attempt_count<MAX_ATTEMPT;attempt_count++){
if(readable_timeout(sockfd,TIMEOUT_SEC,TIMEOUT_USEC)==0){
printf("Socket timeout...attempt %d failed.\n",attempt_count);
if (write(sockfd, required_file_name, len) != len) { //Try again
err_sys_p("Write error.Server is unreachable");
}
}else{
success_flag=1;
break;
}
}
if(success_flag==0){//TODO what to do if MAX_ATTEMT fail? report and end prgm?
err_sys_p("Socket timeout...max no. of attempt failed.\n");
}
//Read the new connection socket ephemeral port number. This serves as ack for filename too.
if ((n = read(sockfd, recvline, MAXLINE)) == -1)
err_sys_p("Read error. Server is unreachable");
recvline[n] = 0; // null terminate
fputs(recvline, stdout);
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(atoi(recvline));
if (inet_pton(AF_INET, serverIP, &servaddr.sin_addr) != 1)
err_sys_p("Cannot convert string IP to binary IP.");
connection_sockfd = sockfd;
if (connect(connection_sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr)) < 0) {
err_sys_p("Connect error");
}
//Send connected ack
strcpy(sendline, "ACK_CONNECTED");
if (write(connection_sockfd, sendline, strlen(sendline)) != strlen(sendline)) {
err_sys_p("Write error.Server is unreachable");
}
printf("%s\n",sendline);
// fflush(NULL);
//Read the file and print output.
while (1) {
if ((n = read(connection_sockfd, recvline, MAXLINE)) == -1)
err_sys_p("Read error. Server is unreachable");
else if (n == 0)
break;
recvline[n] = 0; // null terminate
fputs(recvline, stdout);
//send ACK
/*int len = strlen(sendline);
if (write(connection_sockfd, sendline, len) != len) {
err_sys("Write error.Server is unreachable");
}*/
}
printf("[INFO] File transfer completed.\n");
}
