MP-SPDZ/BMR/network/Server.cpp

#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>

#include <boost/thread.hpp>
#include <iostream>
#include <fstream>
#include <vector>

#include "Server.h"

/* Opens server socket for listening - not yet accepting */
Server::Server(int port, int expected_clients, ServerUpdatable* updatable, unsigned int max_message_size)
	:starter(0),
	 _expected_clients(expected_clients),
	 _port(port),
	 _updatable(updatable),
	 _max_msg_sz(max_message_size)
{
	_clients = new int[expected_clients]();
	_clients_addr = new struct sockaddr_in[expected_clients]();
	timers.resize(expected_clients);

	_servfd = socket(AF_INET, SOCK_STREAM, 0);
	if (-1 == _servfd)
		printf("Server:: Error: socket: \n%s\n",strerror(errno));
	int set_option = 1;
	setsockopt(_servfd, SOL_SOCKET, SO_REUSEADDR, (char*)&set_option,sizeof(set_option));

	memset(&_servaddr, 0, sizeof(_servaddr));
	_servaddr.sin_family = AF_INET;
	_servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	_servaddr.sin_port   = htons(_port);

	if( 0 != ::bind(_servfd, (struct sockaddr *) &_servaddr, sizeof(_servaddr)) )
		printf("Server:: Error binding to %d: \n%s\n", _port, strerror(errno));

	if(0 != listen(_servfd, _expected_clients))
		printf("Server:: Error listen: \n%s\n",strerror(errno));


	starter = new boost::thread(&Server::_start_server, this);
}

Server::~Server() {
#ifdef DEBUG_COMM
	printf("Server:: Server being deleted\n");
#endif
	close(_servfd);
	for (int i=0; i<_expected_clients; i++)
		close(_clients[i]);
	delete[] (_clients);
	delete[] (_clients_addr);
	delete starter;
	for (unsigned i = 0; i < listeners.size(); i++)
		delete listeners[i];
}

void Server::_start_server() {
	socklen_t socksize = sizeof(struct sockaddr_in);
	printf("Server:: Ready for clients...\n");
	for(int i=0; i<_expected_clients; i++) {
        int fd = accept(_servfd, (sockaddr*)&_clients_addr[i], &socksize);
        _clients[i] = fd;
		printf("expected clients = %d, i=%d\n", _expected_clients, i);
        if (fd == -1) {
        	printf("Server:: accept: error in connecting socket\n%s\n",strerror(errno));
        } else {
			printf("Server:: Incoming connection from %s:%d\n",inet_ntoa(_clients_addr[i].sin_addr), ntohs(_clients_addr[i].sin_port));
			// Using the following disables the automatic buffer size (ipv4.tcp_rmem)
			// in favour of the core.rmem_max, which is worse.
			//setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &NETWORK_BUFFER_SIZE, sizeof(NETWORK_BUFFER_SIZE));
			listeners.push_back(new boost::thread(&Server::_listen_to_client, this, i));
        }
	}

	_updatable->ClientsConnected();
}

void Server::_listen_to_client(int id){
	size_t msg_len = 0;
	int n_recv = 0;
	size_t total_received;
	size_t remaining;
	ReceivedMsg msg;
#ifdef DEBUG_FLEXBUF
	cout << "msg from " << id << " stored at " << &msg << endl;
#endif
	while (true) {
		timers[id].start();
		n_recv = recv(_clients[id], &msg_len, sizeof(msg_len), MSG_WAITALL);
		timers[id].stop();
#ifdef DEBUG_COMM
		cout << "message of size " << msg_len << " coming in from " << id << endl;
#endif
		msg.resize(msg_len);
		if (!_handle_recv_len(id, n_recv, sizeof(msg_len)))
			return;
//		printf("Server:: waiting for a message of len = %d\n", msg_len);
		total_received = 0;
		remaining = 0;
		while (total_received != msg_len) {
			remaining = (msg_len-total_received)>_max_msg_sz ? _max_msg_sz : (msg_len-total_received);
			timers[id].start();
			n_recv = recv(_clients[id], msg.data()+total_received, remaining, 0 /* MSG_WAITALL*/);
			timers[id].stop();
//			printf("n_recv = %d\n", n_recv);
			if (!_handle_recv_len(id, n_recv,remaining)) {
				printf("returning\n");
				return;
			}
			total_received += n_recv;
//			printf("total_received = %d\n", total_received);
		}
//		printf("Server:: received %d: \n", msg_len);
		_updatable->NewMsg(msg, &_clients_addr[id]);
	}
	printf("stop listenning to %d\n", id);
}

bool Server::_handle_recv_len(int id, size_t actual_len, size_t expected_len) {
//	printf("Server:: received msg from %d len = %u\n",id, actual_len);
	if (actual_len == 0) {
#ifdef DEBUG_COMM
		printf("Server:: [%d]: Error: n_recv==0 Connection closed\n", id);
#endif
		_updatable->NodeAborted(&_clients_addr[id]);
		return false;
//		exit(1);
	} else if (actual_len == -1U) {
		printf("Server:: [%d]: Error: n_recv==-1. \"%s\"\n",id, strerror(errno));
		_updatable->NodeAborted(&_clients_addr[id]);
		return false;
//		exit(1);
	} else if (actual_len < expected_len) {
//		printf("Server:: [%d]: Error: n_recv < %d; n_recv=%d; \"%d\"\n",id, expected_len, actual_len,strerror(errno));
		return true;
	}
	return true;
}