FIXED: C++ server/client program: "Connection refused" - c++

Question

I'm writing a simple program to transfer files from server to client (both on the same computer for now). Using "telnet 127.0.0.1 [port]", I can succesfully get the file from the server, but when I run the client, the server refuses connection. I suspect that the client is trying to connect to the wrong address, but I'm not sure. I also added some GDB test output if it helps.
Server: "./server 0 4100 bigfile 100 0.01"
int main(int argc, char* argv[])
{
int sockfd;
if(!(sockfd = socket(AF_INET, SOCK_STREAM, 0))) {
error("Failed to create socket");
}
struct sockaddr_in serv_addr, cl_addr;
bzero((void*) &serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = INADDR_ANY;
serv_addr.sin_port = htons(atoi(argv[2]));
if(bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
error("Failed to bind");
}
listen(sockfd, 10);
int fd = open(argv[3], O_RDONLY);
int bufsize = atoi(argv[4]);
int packet_period = atoi(argv[5]);
size_t cl_addr_len = sizeof(cl_addr);
char *buf = new char[bufsize];
while(true) {
int sd;
cout << "waiting for client..." << endl;
if(!(sd = accept(sockfd, (struct sockaddr *) &cl_addr, (socklen_t*) &cl_addr_len))) {
error("Failed to acccept");
}
cout << "Accepted client connection" << endl;
lseek(fd, 0, SEEK_SET);
while(int n = read(fd, buf, bufsize)) {
cout << "Transferring " << buf << endl;
usleep(100000);
write(sd, buf, n);
}
}
}
Client: "./client 0 127.0.0.1 4100 bigfile stats"
int main(int argc, char *argv[])
{
int sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0) {
error("Failed to open socket");
}
struct sockaddr_in serv_addr;
bzero((char *) &serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = inet_addr(argv[2]);
serv_addr.sin_port = htons(atoi(argv[3])); // I tried both htons and htonl
if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) {
error("Failed to connect");
}
int n;
char buf[256];
int fd = open(argv[4], O_RDONLY);
while((n = read(sockfd, buf, 256)) > 0) {
printf("Received: %s\n", buf);
write(fd, buf, n);
}
close(fd);
close(sockfd);
return 0;
}
GDB Output:
(gdb) r
Starting program: [...]/client 0 127.0.0.1 4100 bigfile stats
Breakpoint 1, main (argc=6, argv=0x7fffffffde68) at client.cpp:31
31 if (connect(sockfd,(struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
(gdb) p serv_addr
$1 = {sin_family = 2, sin_port = 0, sin_addr = {s_addr = 16777343},
sin_zero = "\000\000\000\000\000\000\000"}

Answer 1

{sin_family = 2, sin_port = 0, sin_addr = {s_addr = 16777343}, sin_zero = "\000\000\000\000\000\000\000"}
So sin_port is wrong: it shouldn't be zero. The code that sets it is:
serv_addr.sin_port = htonl(atoi(argv[3]));
The problem is here. It should be
serv_addr.sin_port = htons(atoi(argv[3]));
Not today's problem but
printf("Received: %s\n", buf);
should be
printf("Received: %.*s\n", n, buf);