godot/drivers/unix/packet_peer_udp_posix.cpp

/*************************************************************************/
/*  packet_peer_udp_posix.cpp                                            */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
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#include "packet_peer_udp_posix.h"

#ifdef UNIX_ENABLED

#include <errno.h>
#include <netdb.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

#include <netinet/in.h>
#include <stdio.h>

#ifndef NO_FCNTL
#ifdef __HAIKU__
#include <fcntl.h>
#else
#include <sys/fcntl.h>
#endif
#else
#include <sys/ioctl.h>
#endif

#ifdef JAVASCRIPT_ENABLED
#include <arpa/inet.h>
#endif

#include "drivers/unix/socket_helpers.h"

int PacketPeerUDPPosix::get_available_packet_count() const {

	Error err = const_cast<PacketPeerUDPPosix *>(this)->_poll(false);
	if (err != OK)
		return 0;

	return queue_count;
}

Error PacketPeerUDPPosix::get_packet(const uint8_t **r_buffer, int &r_buffer_size) const {

	Error err = const_cast<PacketPeerUDPPosix *>(this)->_poll(false);
	if (err != OK)
		return err;
	if (queue_count == 0)
		return ERR_UNAVAILABLE;

	uint32_t size;
	uint8_t type;
	rb.read(&type, 1, true);
	if (type == IP::TYPE_IPV4) {
		uint8_t ip[4];
		rb.read(ip, 4, true);
		packet_ip.set_ipv4(ip);
	} else {
		uint8_t ipv6[16];
		rb.read(ipv6, 16, true);
		packet_ip.set_ipv6(ipv6);
	};
	rb.read((uint8_t *)&packet_port, 4, true);
	rb.read((uint8_t *)&size, 4, true);
	rb.read(packet_buffer, size, true);
	--queue_count;
	*r_buffer = packet_buffer;
	r_buffer_size = size;
	return OK;
}
Error PacketPeerUDPPosix::put_packet(const uint8_t *p_buffer, int p_buffer_size) {

	ERR_FAIL_COND_V(!peer_addr.is_valid(), ERR_UNCONFIGURED);

	if (sock_type == IP::TYPE_NONE)
		sock_type = peer_addr.is_ipv4() ? IP::TYPE_IPV4 : IP::TYPE_IPV6;

	int sock = _get_socket();
	ERR_FAIL_COND_V(sock == -1, FAILED);
	struct sockaddr_storage addr;
	size_t addr_size = _set_sockaddr(&addr, peer_addr, peer_port, sock_type);

	errno = 0;
	int err;

	_set_sock_blocking(blocking);

	while ((err = sendto(sock, p_buffer, p_buffer_size, 0, (struct sockaddr *)&addr, addr_size)) != p_buffer_size) {

		if (errno != EAGAIN) {
			return FAILED;
		} else if (!blocking) {
			return ERR_UNAVAILABLE;
		}
	}

	return OK;
}

int PacketPeerUDPPosix::get_max_packet_size() const {

	return 512; // uhm maybe not
}

Error PacketPeerUDPPosix::listen(int p_port, IP_Address p_bind_address, int p_recv_buffer_size) {

	ERR_FAIL_COND_V(sockfd != -1, ERR_ALREADY_IN_USE);
	ERR_FAIL_COND_V(!p_bind_address.is_valid() && !p_bind_address.is_wildcard(), ERR_INVALID_PARAMETER);

#ifdef __OpenBSD__
	sock_type = IP::TYPE_IPV4; // OpenBSD does not support dual stacking, fallback to IPv4 only.
#else
	sock_type = IP::TYPE_ANY;
#endif

	if (p_bind_address.is_valid())
		sock_type = p_bind_address.is_ipv4() ? IP::TYPE_IPV4 : IP::TYPE_IPV6;

	int sock = _get_socket();

	if (sock == -1)
		return ERR_CANT_CREATE;

	sockaddr_storage addr = { 0 };
	size_t addr_size = _set_listen_sockaddr(&addr, p_port, sock_type, IP_Address());

	if (bind(sock, (struct sockaddr *)&addr, addr_size) == -1) {
		close();
		return ERR_UNAVAILABLE;
	}
	rb.resize(nearest_shift(p_recv_buffer_size));
	return OK;
}

void PacketPeerUDPPosix::close() {

	if (sockfd != -1)
		::close(sockfd);
	sockfd = -1;
	sock_type = IP::TYPE_NONE;
	rb.resize(16);
	queue_count = 0;
}

Error PacketPeerUDPPosix::wait() {

	return _poll(true);
}

Error PacketPeerUDPPosix::_poll(bool p_wait) {

	if (sockfd == -1) {
		return FAILED;
	}

	_set_sock_blocking(p_wait);

	struct sockaddr_storage from = { 0 };
	socklen_t len = sizeof(struct sockaddr_storage);
	int ret;
	while ((ret = recvfrom(sockfd, recv_buffer, MIN((int)sizeof(recv_buffer), MAX(rb.space_left() - 24, 0)), 0, (struct sockaddr *)&from, &len)) > 0) {

		uint32_t port = 0;

		if (from.ss_family == AF_INET) {
			uint8_t type = (uint8_t)IP::TYPE_IPV4;
			rb.write(&type, 1);
			struct sockaddr_in *sin_from = (struct sockaddr_in *)&from;
			rb.write((uint8_t *)&sin_from->sin_addr, 4);
			port = ntohs(sin_from->sin_port);

		} else if (from.ss_family == AF_INET6) {

			uint8_t type = (uint8_t)IP::TYPE_IPV6;
			rb.write(&type, 1);

			struct sockaddr_in6 *s6_from = (struct sockaddr_in6 *)&from;
			rb.write((uint8_t *)&s6_from->sin6_addr, 16);

			port = ntohs(s6_from->sin6_port);

		} else {
			// WARN_PRINT("Ignoring packet with unknown address family");
			uint8_t type = (uint8_t)IP::TYPE_NONE;
			rb.write(&type, 1);
		};

		rb.write((uint8_t *)&port, 4);
		rb.write((uint8_t *)&ret, 4);
		rb.write(recv_buffer, ret);

		len = sizeof(struct sockaddr_storage);
		++queue_count;
		if (p_wait)
			break;
	};

	// TODO: Should ECONNRESET be handled here?
	if (ret == 0 || (ret == -1 && errno != EAGAIN)) {
		close();
		return FAILED;
	};

	return OK;
}
bool PacketPeerUDPPosix::is_listening() const {

	return sockfd != -1;
}

IP_Address PacketPeerUDPPosix::get_packet_address() const {

	return packet_ip;
}

int PacketPeerUDPPosix::get_packet_port() const {

	return packet_port;
}

int PacketPeerUDPPosix::_get_socket() {

	ERR_FAIL_COND_V(sock_type == IP::TYPE_NONE, -1);

	if (sockfd != -1)
		return sockfd;

	sockfd = _socket_create(sock_type, SOCK_DGRAM, IPPROTO_UDP);

	if (sockfd != -1)
		_set_sock_blocking(false);

	return sockfd;
}

void PacketPeerUDPPosix::_set_sock_blocking(bool p_blocking) {

	if (sock_blocking == p_blocking)
		return;

	sock_blocking = p_blocking;

#ifndef NO_FCNTL
	int opts = fcntl(sockfd, F_GETFL);
	int ret = 0;
	if (sock_blocking)
		ret = fcntl(sockfd, F_SETFL, opts & ~O_NONBLOCK);
	else
		ret = fcntl(sockfd, F_SETFL, opts | O_NONBLOCK);
	if (ret == -1)
		perror("setting non-block mode");
#else
	int bval = sock_blocking ? 0 : 1;
	if (ioctl(sockfd, FIONBIO, &bval) == -1)
		perror("setting non-block mode");
#endif
}

void PacketPeerUDPPosix::set_send_address(const IP_Address &p_address, int p_port) {

	peer_addr = p_address;
	peer_port = p_port;
}

PacketPeerUDP *PacketPeerUDPPosix::_create() {

	return memnew(PacketPeerUDPPosix);
};

void PacketPeerUDPPosix::make_default() {

	PacketPeerUDP::_create = PacketPeerUDPPosix::_create;
};

PacketPeerUDPPosix::PacketPeerUDPPosix() {

	blocking = true;
	sock_blocking = true;
	sockfd = -1;
	packet_port = 0;
	queue_count = 0;
	peer_port = 0;
	sock_type = IP::TYPE_NONE;
	rb.resize(16);
}

PacketPeerUDPPosix::~PacketPeerUDPPosix() {

	close();
}
#endif