ObjFW  Artifact [11bd6fb256]

Artifact 11bd6fb256ee6c37898dedeb5dcee70384aaad8dd7016d068eb4f7d8ab86776c:

• File src/OFDDPSocket.m — part of check-in [9c2f20e736] at 2022-11-03 00:14:27 on branch trunk — OFDDPSocket: Don't include the type with the data

  This seems to be an oddity limited to OSes that have implemented DDP
  exclusively for netatalk, while macOS and Windows don't include it with
  the data.

  While on macOS it's possible to achieve the previous behavior via some
  hacks, this is impossible on Windows, so the proper approach is to
  handle it like everybody else: Specify the protocol type when binding
  and only handle packets of the correct protocol type. (user: js, size: 7082) [annotate] [blame] [check-ins using] [more...]

/*
 * Copyright (c) 2008-2022 Jonathan Schleifer <js@nil.im>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#include "config.h"

#include <errno.h>

#ifdef HAVE_FCNTL_H
# include <fcntl.h>
#endif

#import "OFDDPSocket.h"
#import "OFSocket.h"
#import "OFSocket+Private.h"

#import "OFAlreadyConnectedException.h"
#import "OFBindDDPSocketFailedException.h"
#import "OFInvalidArgumentException.h"
#import "OFNotOpenException.h"
#import "OFReadFailedException.h"
#import "OFWriteFailedException.h"

#ifdef OF_HAVE_NETAT_APPLETALK_H
# include <netat/ddp.h>
# include <sys/ioctl.h>

/* Unfortulately, there is no struct for the following in userland headers */
struct ATInterfaceConfig {
	char interfaceName[16];
	unsigned int flags;
	struct at_addr address, router;
	unsigned short netStart, netEnd;
	at_nvestr_t zoneName;
};
#endif

#ifndef ATPROTO_BASE
# define ATPROTO_BASE 0
#endif

@implementation OFDDPSocket
@dynamic delegate;

- (OFSocketAddress)bindToNetwork: (uint16_t)network
			    node: (uint8_t)node
			    port: (uint8_t)port
		    protocolType: (uint8_t)protocolType
{
#ifdef OF_MACOS
	const int one = 1;
	struct ATInterfaceConfig config = { { 0 } };
#endif
	OFSocketAddress address;
#if SOCK_CLOEXEC == 0 && defined(HAVE_FCNTL_H) && defined(FD_CLOEXEC)
	int flags;
#endif

	if (protocolType == 0)
		@throw [OFInvalidArgumentException exception];

	if (_socket != OFInvalidSocketHandle)
		@throw [OFAlreadyConnectedException exceptionWithSocket: self];

	address = OFSocketAddressMakeAppleTalk(network, node, port);

#ifdef OF_MACOS
	if ((_socket = socket(address.sockaddr.at.sat_family,
	    SOCK_RAW | SOCK_CLOEXEC, protocolType)) == OFInvalidSocketHandle)
#else
	if ((_socket = socket(address.sockaddr.at.sat_family,
	    SOCK_DGRAM | SOCK_CLOEXEC, ATPROTO_BASE + protocolType)) ==
	    OFInvalidSocketHandle)
#endif
		@throw [OFBindDDPSocketFailedException
		    exceptionWithNetwork: network
				    node: node
				    port: port
			    protocolType: protocolType
				  socket: self
				   errNo: OFSocketErrNo()];

	_canBlock = true;

#if SOCK_CLOEXEC == 0 && defined(HAVE_FCNTL_H) && defined(FD_CLOEXEC)
	if ((flags = fcntl(_socket, F_GETFD, 0)) != -1)
		fcntl(_socket, F_SETFD, flags | FD_CLOEXEC);
#endif

	if (bind(_socket, (struct sockaddr *)&address.sockaddr,
	    address.length) != 0) {
		int errNo = OFSocketErrNo();

		closesocket(_socket);
		_socket = OFInvalidSocketHandle;

		@throw [OFBindDDPSocketFailedException
		    exceptionWithNetwork: network
				    node: node
				    port: port
			    protocolType: protocolType
				  socket: self
				   errNo: errNo];
	}

	memset(&address, 0, sizeof(address));
	address.family = OFSocketAddressFamilyAppleTalk;
	address.length = (socklen_t)sizeof(address.sockaddr);

	if (OFGetSockName(_socket, (struct sockaddr *)&address.sockaddr,
	    &address.length) != 0) {
		int errNo = OFSocketErrNo();

		closesocket(_socket);
		_socket = OFInvalidSocketHandle;

		@throw [OFBindDDPSocketFailedException
		    exceptionWithNetwork: network
				    node: node
				    port: port
			    protocolType: protocolType
				  socket: self
				   errNo: errNo];
	}

	if (address.sockaddr.at.sat_family != AF_APPLETALK) {
		closesocket(_socket);
		_socket = OFInvalidSocketHandle;

		@throw [OFBindDDPSocketFailedException
		    exceptionWithNetwork: network
				    node: node
				    port: port
			    protocolType: protocolType
				  socket: self
				   errNo: EAFNOSUPPORT];
	}

#ifdef OF_MACOS
	if (setsockopt(_socket, ATPROTO_NONE, DDP_STRIPHDR, &one,
	    sizeof(one)) != 0 || ioctl(_socket, _IOWR('a', 2,
	    struct ATInterfaceConfig), &config) != 0)
		@throw [OFBindDDPSocketFailedException
		    exceptionWithNetwork: network
				    node: node
				    port: port
			    protocolType: protocolType
				  socket: self
				   errNo: OFSocketErrNo()];

	OFSocketAddressSetAppleTalkNetwork(&address, config.address.s_net);
	OFSocketAddressSetAppleTalkNode(&address, config.address.s_node);
#endif

#if !defined(OF_MACOS) && !defined(OF_WINDOWS)
	_protocolType = protocolType;
#endif

	return address;
}

/*
 * Everybody but macOS and Windows is probably using a netatalk-compatible
 * implementation, which includes the protocol type as the first byte of the
 * data instead of considering it part of the header.
 *
 * The following overrides prepend the protocol type when sending and compare
 * and strip it when receiving.
 *
 * Unfortunately, the downside of this is that the only way to handle receiving
 * a packet with the wrong protocol type is to throw an exception with errNo
 * ENOMSG, while macOS and Windows just filter those out in the kernel.
 * Returning 0 would mean this is indistinguishable from an empty packet, so it
 * has to be an exception.
 */
#if !defined(OF_MACOS) && !defined(OF_WINDOWS)
- (size_t)receiveIntoBuffer: (void *)buffer
		     length: (size_t)length
		     sender: (OFSocketAddress *)sender
{
	ssize_t ret;
	uint8_t protocolType;
	struct iovec iov[2] = {
		{ &protocolType, 1 },
		{ buffer, length }
	};
	struct msghdr msg = {
		.msg_name = (struct sockaddr *)&sender->sockaddr,
		.msg_namelen = (socklen_t)sizeof(sender->sockaddr),
		.msg_iov = iov,
		.msg_iovlen = 2
	};

	if (_socket == OFInvalidSocketHandle)
		@throw [OFNotOpenException exceptionWithObject: self];

	if ((ret = recvmsg(_socket, &msg, 0)) < 0)
		@throw [OFReadFailedException
		    exceptionWithObject: self
			requestedLength: length
				  errNo: OFSocketErrNo()];

	if (ret < 1 || protocolType != _protocolType)
		@throw [OFReadFailedException exceptionWithObject: self
						  requestedLength: length
							    errNo: ENOMSG];

	sender->length = msg.msg_namelen;
	sender->family = OFSocketAddressFamilyAppleTalk;

	return ret - 1;
}

- (void)sendBuffer: (const void *)buffer
	    length: (size_t)length
	  receiver: (const OFSocketAddress *)receiver
{
	struct iovec iov[2] = {
		{ &_protocolType, 1 },
		{ (void *)buffer, length }
	};
	struct msghdr msg = {
		.msg_name = (struct sockaddr *)&receiver->sockaddr,
		.msg_namelen = receiver->length,
		.msg_iov = iov,
		.msg_iovlen = 2
	};
	ssize_t bytesWritten;

	if (_socket == OFInvalidSocketHandle)
		@throw [OFNotOpenException exceptionWithObject: self];

	if ((bytesWritten = sendmsg(_socket, &msg, 0)) < 0)
		@throw [OFWriteFailedException
		    exceptionWithObject: self
			requestedLength: length
			   bytesWritten: 0
				  errNo: OFSocketErrNo()];

	if ((size_t)bytesWritten != length + 1) {
		bytesWritten--;

		if (bytesWritten < 0)
			bytesWritten = 0;

		@throw [OFWriteFailedException exceptionWithObject: self
						   requestedLength: length
						      bytesWritten: bytesWritten
							     errNo: 0];
	}
}
#endif
@end