text: /*************************************************************************/
  /*  net_socket_posix.cpp                                                 */
  /*************************************************************************/
  /*                       This file is part of:                           */
  /*                           GODOT ENGINE                                */
  /*                      https://godotengine.org                          */
  /*************************************************************************/
  /* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
  /* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
  /*                                                                       */
  /* Permission is hereby granted, free of charge, to any person obtaining */
  /* a copy of this software and associated documentation files (the       */
  /* "Software"), to deal in the Software without restriction, including   */
  /* without limitation the rights to use, copy, modify, merge, publish,   */
  /* distribute, sublicense, and/or sell copies of the Software, and to    */
  /* permit persons to whom the Software is furnished to do so, subject to */
  /* the following conditions:                                             */
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  /* The above copyright notice and this permission notice shall be        */
  /* included in all copies or substantial portions of the Software.       */
  /*                                                                       */
  /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
  /* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
  /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
  /* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
  /* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
  /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
  /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
  /*************************************************************************/
  
  #include "net_socket_posix.h"
  
  #if defined(UNIX_ENABLED)
  
  #include <errno.h>
  #include <netdb.h>
  #include <poll.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sys/ioctl.h>
  #include <sys/types.h>
  #include <unistd.h>
  #ifndef NO_FCNTL
  #include <fcntl.h>
  #else
  #include <sys/ioctl.h>
  #endif
  #include <netinet/in.h>
  
  #include <sys/socket.h>
  #ifdef JAVASCRIPT_ENABLED
  #include <arpa/inet.h>
  #endif
  
  #include <netinet/tcp.h>
  
  #if defined(__APPLE__)
  #define MSG_NOSIGNAL SO_NOSIGPIPE
  #endif
  
  // Some custom defines to minimize ifdefs
  #define SOCK_EMPTY -1
  #define SOCK_BUF(x) x
  #define SOCK_CBUF(x) x
  #define SOCK_IOCTL ioctl
  #define SOCK_CLOSE ::close
  
  /* Windows */
  #elif defined(WINDOWS_ENABLED)
  #include <winsock2.h>
  #include <ws2tcpip.h>
  
  #include <mswsock.h>
  // Some custom defines to minimize ifdefs
  #define SOCK_EMPTY INVALID_SOCKET
  #define SOCK_BUF(x) (char *)(x)
  #define SOCK_CBUF(x) (const char *)(x)
  #define SOCK_IOCTL ioctlsocket
  #define SOCK_CLOSE closesocket
  
  // Windows doesn't have this flag
  #ifndef MSG_NOSIGNAL
  #define MSG_NOSIGNAL 0
  #endif
  // Workaround missing flag in MinGW
  #if defined(__MINGW32__) && !defined(SIO_UDP_NETRESET)
  #define SIO_UDP_NETRESET _WSAIOW(IOC_VENDOR, 15)
  #endif
  
  #endif
  
  size_t NetSocketPosix::_set_addr_storage(struct sockaddr_storage *p_addr, const IP_Address &p_ip, uint16_t p_port, IP::Type p_ip_type) {
  
  	memset(p_addr, 0, sizeof(struct sockaddr_storage));
  	if (p_ip_type == IP::TYPE_IPV6 || p_ip_type == IP::TYPE_ANY) { // IPv6 socket
  
  		// IPv6 only socket with IPv4 address
  		ERR_FAIL_COND_V(!p_ip.is_wildcard() && p_ip_type == IP::TYPE_IPV6 && p_ip.is_ipv4(), 0);
  
  		struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)p_addr;
  		addr6->sin6_family = AF_INET6;
  		addr6->sin6_port = htons(p_port);
  		if (p_ip.is_valid()) {
  			copymem(&addr6->sin6_addr.s6_addr, p_ip.get_ipv6(), 16);
  		} else {
  			addr6->sin6_addr = in6addr_any;
  		}
  		return sizeof(sockaddr_in6);
  	} else { // IPv4 socket
  
  		// IPv4 socket with IPv6 address
  		ERR_FAIL_COND_V(!p_ip.is_wildcard() && !p_ip.is_ipv4(), 0);
  
  		struct sockaddr_in *addr4 = (struct sockaddr_in *)p_addr;
  		addr4->sin_family = AF_INET;
  		addr4->sin_port = htons(p_port); // short, network byte order
  
  		if (p_ip.is_valid()) {
  			copymem(&addr4->sin_addr.s_addr, p_ip.get_ipv4(), 4);
  		} else {
  			addr4->sin_addr.s_addr = INADDR_ANY;
  		}
  
  		return sizeof(sockaddr_in);
  	}
  }
  
  void NetSocketPosix::_set_ip_port(struct sockaddr_storage *p_addr, IP_Address &r_ip, uint16_t &r_port) {
  
  	if (p_addr->ss_family == AF_INET) {
  
  		struct sockaddr_in *addr4 = (struct sockaddr_in *)p_addr;
  		r_ip.set_ipv4((uint8_t *)&(addr4->sin_addr.s_addr));
  
  		r_port = ntohs(addr4->sin_port);
  
  	} else if (p_addr->ss_family == AF_INET6) {
  
  		struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)p_addr;
  		r_ip.set_ipv6(addr6->sin6_addr.s6_addr);
  
  		r_port = ntohs(addr6->sin6_port);
  	};
  }
  
  NetSocket *NetSocketPosix::_create_func() {
  	return memnew(NetSocketPosix);
  }
  
  void NetSocketPosix::make_default() {
  #if defined(WINDOWS_ENABLED)
  	if (_create == NULL) {
  		WSADATA data;
  		WSAStartup(MAKEWORD(2, 2), &data);
  	}
  #endif
  	_create = _create_func;
  }
  
  void NetSocketPosix::cleanup() {
  #if defined(WINDOWS_ENABLED)
  	if (_create != NULL) {
  		WSACleanup();
  	}
  	_create = NULL;
  #endif
  }
  
  NetSocketPosix::NetSocketPosix() :
  		_sock(SOCK_EMPTY),
  		_ip_type(IP::TYPE_NONE),
  		_is_stream(false) {
  }
  
  NetSocketPosix::~NetSocketPosix() {
  	close();
  }
  
  NetSocketPosix::NetError NetSocketPosix::_get_socket_error() {
  #if defined(WINDOWS_ENABLED)
  	int err = WSAGetLastError();
  
  	if (err == WSAEISCONN)
  		return ERR_NET_IS_CONNECTED;
  	if (err == WSAEINPROGRESS || err == WSAEALREADY)
  		return ERR_NET_IN_PROGRESS;
  	if (err == WSAEWOULDBLOCK)
  		return ERR_NET_WOULD_BLOCK;
  	ERR_PRINTS("Socket error: " + itos(err));
  	return ERR_NET_OTHER;
  #else
  	if (errno == EISCONN)
  		return ERR_NET_IS_CONNECTED;
  	if (errno == EINPROGRESS || errno == EALREADY)
  		return ERR_NET_IN_PROGRESS;
  	if (errno == EAGAIN || errno == EWOULDBLOCK)
  		return ERR_NET_WOULD_BLOCK;
  	ERR_PRINTS("Socket error: " + itos(errno));
  	return ERR_NET_OTHER;
  #endif
  }
  
  bool NetSocketPosix::_can_use_ip(const IP_Address p_ip, const bool p_for_bind) const {
  
  	if (p_for_bind && !(p_ip.is_valid() || p_ip.is_wildcard())) {
  		return false;
  	} else if (!p_for_bind && !p_ip.is_valid()) {
  		return false;
  	}
  	// Check if socket support this IP type.
  	IP::Type type = p_ip.is_ipv4() ? IP::TYPE_IPV4 : IP::TYPE_IPV6;
  	if (_ip_type != IP::TYPE_ANY && !p_ip.is_wildcard() && _ip_type != type) {
  		return false;
  	}
  	return true;
  }
  
  void NetSocketPosix::_set_socket(SOCKET_TYPE p_sock, IP::Type p_ip_type, bool p_is_stream) {
  	_sock = p_sock;
  	_ip_type = p_ip_type;
  	_is_stream = p_is_stream;
  }
  
  Error NetSocketPosix::open(Type p_sock_type, IP::Type &ip_type) {
  	ERR_FAIL_COND_V(is_open(), ERR_ALREADY_IN_USE);
  	ERR_FAIL_COND_V(ip_type > IP::TYPE_ANY || ip_type < IP::TYPE_NONE, ERR_INVALID_PARAMETER);
  
  #if defined(__OpenBSD__)
  	// OpenBSD does not support dual stacking, fallback to IPv4 only.
  	if (ip_type == IP::TYPE_ANY)
  		ip_type = IP::TYPE_IPV4;
  #endif
  
  	int family = ip_type == IP::TYPE_IPV4 ? AF_INET : AF_INET6;
  	int protocol = p_sock_type == TYPE_TCP ? IPPROTO_TCP : IPPROTO_UDP;
  	int type = p_sock_type == TYPE_TCP ? SOCK_STREAM : SOCK_DGRAM;
  	_sock = socket(family, type, protocol);
  
  	if (_sock == SOCK_EMPTY && ip_type == IP::TYPE_ANY) {
  		// Careful here, changing the referenced parameter so the caller knows that we are using an IPv4 socket
  		// in place of a dual stack one, and further calls to _set_sock_addr will work as expected.
  		ip_type = IP::TYPE_IPV4;
  		family = AF_INET;
  		_sock = socket(family, type, protocol);
  	}
  
  	ERR_FAIL_COND_V(_sock == SOCK_EMPTY, FAILED);
  	_ip_type = ip_type;
  
  	if (family == AF_INET6) {
  		// Select IPv4 over IPv6 mapping
  		set_ipv6_only_enabled(ip_type != IP::TYPE_ANY);
  	}
  
  	if (protocol == IPPROTO_UDP && ip_type != IP::TYPE_IPV6) {
  		// Enable broadcasting for UDP sockets if it's not IPv6 only (IPv6 has no broadcast option).
  		set_broadcasting_enabled(true);
  	}
  
  	_is_stream = p_sock_type == TYPE_TCP;
  
  #if defined(WINDOWS_ENABLED)
  	if (!_is_stream) {
  		// Disable windows feature/bug reporting WSAECONNRESET/WSAENETRESET when
  		// recv/recvfrom and an ICMP reply was received from a previous send/sendto.
  		unsigned long disable = 0;
  		if (ioctlsocket(_sock, SIO_UDP_CONNRESET, &disable) == SOCKET_ERROR) {
  			print_verbose("Unable to turn off UDP WSAECONNRESET behaviour on Windows");
  		}
  		if (ioctlsocket(_sock, SIO_UDP_NETRESET, &disable) == SOCKET_ERROR) {
  			// This feature seems not to be supported on wine.
  			print_verbose("Unable to turn off UDP WSAENETRESET behaviour on Windows");
  		}
  	}
  #endif
  	return OK;
  }
  
  void NetSocketPosix::close() {
  
  	if (_sock != SOCK_EMPTY)
  		SOCK_CLOSE(_sock);
  
  	_sock = SOCK_EMPTY;
  	_ip_type = IP::TYPE_NONE;
  	_is_stream = false;
  }
  
  Error NetSocketPosix::bind(IP_Address p_addr, uint16_t p_port) {
  
  	ERR_FAIL_COND_V(!is_open(), ERR_UNCONFIGURED);
  	ERR_FAIL_COND_V(!_can_use_ip(p_addr, true), ERR_INVALID_PARAMETER);
  
  	sockaddr_storage addr;
  	size_t addr_size = _set_addr_storage(&addr, p_addr, p_port, _ip_type);
  
  	if (::bind(_sock, (struct sockaddr *)&addr, addr_size) == SOCK_EMPTY) {
  		close();
  		ERR_FAIL_V(ERR_UNAVAILABLE);
  	}
  
  	return OK;
  }
  
  Error NetSocketPosix::listen(int p_max_pending) {
  	ERR_FAIL_COND_V(!is_open(), ERR_UNCONFIGURED);
  
  	if (::listen(_sock, p_max_pending) == SOCK_EMPTY) {
  
  		close();
  		ERR_FAIL_V(FAILED);
  	};
  
  	return OK;
  }
  
  Error NetSocketPosix::connect_to_host(IP_Address p_host, uint16_t p_port) {
  
  	ERR_FAIL_COND_V(!is_open(), ERR_UNCONFIGURED);
  	ERR_FAIL_COND_V(!_can_use_ip(p_host, false), ERR_INVALID_PARAMETER);
  
  	struct sockaddr_storage addr;
  	size_t addr_size = _set_addr_storage(&addr, p_host, p_port, _ip_type);
  
  	if (::connect(_sock, (struct sockaddr *)&addr, addr_size) == SOCK_EMPTY) {
  
  		NetError err = _get_socket_error();
  
  		switch (err) {
  			// We are already connected
  			case ERR_NET_IS_CONNECTED:
  				return OK;
  			// Still waiting to connect, try again in a while
  			case ERR_NET_WOULD_BLOCK:
  			case ERR_NET_IN_PROGRESS:
  				return ERR_BUSY;
  			default:
  				ERR_PRINT("Connection to remote host failed!");
  				close();
  				return FAILED;
  		}
  	}
  
  	return OK;
  }
  
  Error NetSocketPosix::poll(PollType p_type, int p_timeout) const {
  
  	ERR_FAIL_COND_V(!is_open(), ERR_UNCONFIGURED);
  
  #if defined(WINDOWS_ENABLED)
  	bool ready = false;
  	fd_set rd, wr, ex;
  	fd_set *rdp = NULL;
  	fd_set *wrp = NULL;
  	FD_ZERO(&rd);
  	FD_ZERO(&wr);
  	FD_ZERO(&ex);
  	FD_SET(_sock, &ex);
  	struct timeval timeout = { p_timeout, 0 };
  	// For blocking operation, pass NULL timeout pointer to select.
  	struct timeval *tp = NULL;
  	if (p_timeout >= 0) {
  		//  If timeout is non-negative, we want to specify the timeout instead.
  		tp = &timeout;
  	}
  
  	switch (p_type) {
  		case POLL_TYPE_IN:
  			FD_SET(_sock, &rd);
  			rdp = &rd;
  			break;
  		case POLL_TYPE_OUT:
  			FD_SET(_sock, &wr);
  			wrp = &wr;
  			break;
  		case POLL_TYPE_IN_OUT:
  			FD_SET(_sock, &rd);
  			FD_SET(_sock, &wr);
  			rdp = &rd;
  			wrp = &wr;
  	}
  	int ret = select(1, rdp, wrp, &ex, tp);
  
  	ERR_FAIL_COND_V(ret == SOCKET_ERROR, FAILED);
  
  	if (ret == 0)
  		return ERR_BUSY;
  
  	ERR_FAIL_COND_V(FD_ISSET(_sock, &ex), FAILED);
  
  	if (rdp && FD_ISSET(_sock, rdp))
  		ready = true;
  	if (wrp && FD_ISSET(_sock, wrp))
  		ready = true;
  
  	return ready ? OK : ERR_BUSY;
  #else
  	struct pollfd pfd;
  	pfd.fd = _sock;
  	pfd.events = POLLIN;
  	pfd.revents = 0;
  
  	switch (p_type) {
  		case POLL_TYPE_IN:
  			pfd.events = POLLIN;
  			break;
  		case POLL_TYPE_OUT:
  			pfd.events = POLLOUT;
  			break;
  		case POLL_TYPE_IN_OUT:
  			pfd.events = POLLOUT || POLLIN;
  	}
  
  	int ret = ::poll(&pfd, 1, p_timeout);
  
  	ERR_FAIL_COND_V(ret < 0, FAILED);
  	ERR_FAIL_COND_V(pfd.revents & POLLERR, FAILED);
  
  	if (ret == 0)
  		return ERR_BUSY;
  
  	return OK;
  #endif
  }
  
  Error NetSocketPosix::recv(uint8_t *p_buffer, int p_len, int &r_read) {
  	ERR_FAIL_COND_V(!is_open(), ERR_UNCONFIGURED);
  
  	r_read = ::recv(_sock, SOCK_BUF(p_buffer), p_len, 0);
  
  	if (r_read < 0) {
  		NetError err = _get_socket_error();
  		if (err == ERR_NET_WOULD_BLOCK)
  			return ERR_BUSY;
  
  		return FAILED;
  	}
  
  	return OK;
  }
  
  Error NetSocketPosix::recvfrom(uint8_t *p_buffer, int p_len, int &r_read, IP_Address &r_ip, uint16_t &r_port) {
  	ERR_FAIL_COND_V(!is_open(), ERR_UNCONFIGURED);
  
  	struct sockaddr_storage from;
  	socklen_t len = sizeof(struct sockaddr_storage);
  	memset(&from, 0, len);
  
  	r_read = ::recvfrom(_sock, SOCK_BUF(p_buffer), p_len, 0, (struct sockaddr *)&from, &len);
  
  	if (r_read < 0) {
  		NetError err = _get_socket_error();
  		if (err == ERR_NET_WOULD_BLOCK)
  			return ERR_BUSY;
  
  		return FAILED;
  	}
  
  	if (from.ss_family == AF_INET) {
  		struct sockaddr_in *sin_from = (struct sockaddr_in *)&from;
  		r_ip.set_ipv4((uint8_t *)&sin_from->sin_addr);
  		r_port = ntohs(sin_from->sin_port);
  	} else if (from.ss_family == AF_INET6) {
  		struct sockaddr_in6 *s6_from = (struct sockaddr_in6 *)&from;
  		r_ip.set_ipv6((uint8_t *)&s6_from->sin6_addr);
  		r_port = ntohs(s6_from->sin6_port);
  	} else {
  		// Unsupported socket family, should never happen.
  		ERR_FAIL_V(FAILED);
  	}
  
  	return OK;
  }
  
  Error NetSocketPosix::send(const uint8_t *p_buffer, int p_len, int &r_sent) {
  	ERR_FAIL_COND_V(!is_open(), ERR_UNCONFIGURED);
  
  	int flags = 0;
  	if (_is_stream)
  		flags = MSG_NOSIGNAL;
  	r_sent = ::send(_sock, SOCK_CBUF(p_buffer), p_len, flags);
  
  	if (r_sent < 0) {
  		NetError err = _get_socket_error();
  		if (err == ERR_NET_WOULD_BLOCK)
  			return ERR_BUSY;
  
  		return FAILED;
  	}
  
  	return OK;
  }
  
  Error NetSocketPosix::sendto(const uint8_t *p_buffer, int p_len, int &r_sent, IP_Address p_ip, uint16_t p_port) {
  	ERR_FAIL_COND_V(!is_open(), ERR_UNCONFIGURED);
  
  	struct sockaddr_storage addr;
  	size_t addr_size = _set_addr_storage(&addr, p_ip, p_port, _ip_type);
  	r_sent = ::sendto(_sock, SOCK_CBUF(p_buffer), p_len, 0, (struct sockaddr *)&addr, addr_size);
  
  	if (r_sent < 0) {
  		NetError err = _get_socket_error();
  		if (err == ERR_NET_WOULD_BLOCK)
  			return ERR_BUSY;
  
  		return FAILED;
  	}
  
  	return OK;
  }
  
  void NetSocketPosix::set_broadcasting_enabled(bool p_enabled) {
  	ERR_FAIL_COND(!is_open());
  	// IPv6 has no broadcast support.
  	ERR_FAIL_COND(_ip_type == IP::TYPE_IPV6);
  
  	int par = p_enabled ? 1 : 0;
  	if (setsockopt(_sock, SOL_SOCKET, SO_BROADCAST, SOCK_CBUF(&par), sizeof(int)) != 0) {
  		WARN_PRINT("Unable to change broadcast setting");
  	}
  }
  
  void NetSocketPosix::set_blocking_enabled(bool p_enabled) {
  	ERR_FAIL_COND(!is_open());
  
  	int ret = 0;
  #if defined(WINDOWS_ENABLED) || defined(NO_FCNTL)
  	unsigned long par = p_enabled ? 0 : 1;
  	ret = SOCK_IOCTL(_sock, FIONBIO, &par);
  #else
  	int opts = fcntl(_sock, F_GETFL);
  	if (p_enabled)
  		ret = fcntl(_sock, F_SETFL, opts & ~O_NONBLOCK);
  	else
  		ret = fcntl(_sock, F_SETFL, opts | O_NONBLOCK);
  #endif
  
  	if (ret != 0)
  		WARN_PRINT("Unable to change non-block mode");
  }
  
  void NetSocketPosix::set_ipv6_only_enabled(bool p_enabled) {
  	ERR_FAIL_COND(!is_open());
  	// This option is only available in IPv6 sockets.
  	ERR_FAIL_COND(_ip_type == IP::TYPE_IPV4);
  
  	int par = p_enabled ? 1 : 0;
  	if (setsockopt(_sock, IPPROTO_IPV6, IPV6_V6ONLY, SOCK_CBUF(&par), sizeof(int)) != 0) {
  		WARN_PRINT("Unable to change IPv4 address mapping over IPv6 option");
  	}
  }
  
  void NetSocketPosix::set_tcp_no_delay_enabled(bool p_enabled) {
  	ERR_FAIL_COND(!is_open());
  	ERR_FAIL_COND(!_is_stream); // Not TCP
  
  	int par = p_enabled ? 1 : 0;
  	if (setsockopt(_sock, IPPROTO_TCP, TCP_NODELAY, SOCK_CBUF(&par), sizeof(int)) < 0) {
  		ERR_PRINT("Unable to set TCP no delay option");
  	}
  }
  
  void NetSocketPosix::set_reuse_address_enabled(bool p_enabled) {
  	ERR_FAIL_COND(!is_open());
  
  	int par = p_enabled ? 1 : 0;
  	if (setsockopt(_sock, SOL_SOCKET, SO_REUSEADDR, SOCK_CBUF(&par), sizeof(int)) < 0) {
  		WARN_PRINT("Unable to set socket REUSEADDR option!");
  	}
  }
  
  void NetSocketPosix::set_reuse_port_enabled(bool p_enabled) {
  // Windows does not have this option, as it is always ON when setting REUSEADDR.
  #ifndef WINDOWS_ENABLED
  	ERR_FAIL_COND(!is_open());
  
  	int par = p_enabled ? 1 : 0;
  	if (setsockopt(_sock, SOL_SOCKET, SO_REUSEPORT, SOCK_CBUF(&par), sizeof(int)) < 0) {
  		WARN_PRINT("Unable to set socket REUSEPORT option!");
  	}
  #endif
  }
  
  bool NetSocketPosix::is_open() const {
  	return _sock != SOCK_EMPTY;
  }
  
  int NetSocketPosix::get_available_bytes() const {
  
  	ERR_FAIL_COND_V(_sock == SOCK_EMPTY, -1);
  
  	unsigned long len;
  	int ret = SOCK_IOCTL(_sock, FIONREAD, &len);
  	ERR_FAIL_COND_V(ret == -1, 0);
  	return len;
  }
  
  Ref<NetSocket> NetSocketPosix::accept(IP_Address &r_ip, uint16_t &r_port) {
  
  	Ref<NetSocket> out;
  	ERR_FAIL_COND_V(!is_open(), out);
  
  	struct sockaddr_storage their_addr;
  	socklen_t size = sizeof(their_addr);
  	SOCKET_TYPE fd = ::accept(_sock, (struct sockaddr *)&their_addr, &size);
  	ERR_FAIL_COND_V(fd == SOCK_EMPTY, out);
  
  	_set_ip_port(&their_addr, r_ip, r_port);
  
  	NetSocketPosix *ns = memnew(NetSocketPosix);
  	ns->_set_socket(fd, _ip_type, _is_stream);
  	ns->set_blocking_enabled(false);
  	return Ref<NetSocket>(ns);
  }
  