Worker thread exits some time later - c

Question

Here is a simple echo program using sockets and multi threads, it compiles and runs well in my Ubuntu if the client(via telnet) and server run on the same machine, but when I remotely connect to the server via telnet from another machine, it initially runs well(echos my message back every time), but some time later, there is no echo anymore even the telnet session is still alive, i am not sure where the problem is, can someone give some hits on this? I am new to multi thread programming and socket programming, learning on that.
#define ERROR -1
#define MAX_CLIENTS 2
#define MAX_DATA 1024
void* worker(void* sockId)
{
int socketId = *(int*)sockId;
int data_len = 1;
char data[MAX_DATA];
while(data_len > 0)
{
data_len = recv(socketId, data, MAX_DATA, 0);
if (data_len > 0)
{
send(socketId, data, data_len, 0);
data[data_len] = '\0';
printf("Sent message: %s", data);
}
}
printf("Client disconnected\n");
close(socketId);
}
int main(int argc, char* argv[])
{
if (argc <= 1)
{
printf("missing argument: port\n");
exit(-1);
}
struct sockaddr_in server;
struct sockaddr_in client;
int sock;
int new_connection;
int sockaddr_len = sizeof(struct sockaddr_in);
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == ERROR)
{
perror("server socket: ");
exit(-1);
}
server.sin_family = AF_INET;
server.sin_port = htons(atoi(argv[1]));
server.sin_addr.s_addr = INADDR_ANY;
bzero(&server.sin_zero, 8);
if ((bind(sock, (struct sockaddr*)&server, sockaddr_len)) == ERROR)
{
perror("bind: ");
exit(-1);
}
if ((listen(sock, MAX_CLIENTS)) == ERROR)
{
perror("listen: ");
exit(-1);
}
while(1)
{
if ((new_connection = accept(sock, (struct sockaddr*)&client, &sockaddr_len)) == ERROR)
{
perror("accpet: ");
exit(-1);
}
printf("New Client connected from port: %d and IP: %s\n", ntohs(client.sin_port), inet_ntoa(client.sin_addr));
pthread_t thread;
pthread_create(&thread, NULL, worker, (void*)&new_connection);
pthread_detach(thread);
}
close(sock);
pthread_exit(NULL);
return 0;
}

Answer 1

Add some logging and you'll probably find that your code is blocked in send. You use naive, sequential I/O, so if the other end of the connection stops reading data, soon you do too.