haiku-beta6/src/add-ons/kernel/network/stack/net_socket.cpp

/*
 * Copyright 2006-2008, Haiku, Inc. All Rights Reserved.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *		Axel Dörfler, [email protected]
 */


#include "stack_private.h"

#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/time.h>

#include <new>

#include <Drivers.h>
#include <KernelExport.h>
#include <Select.h>
#include <team.h>
#include <util/AutoLock.h>
#include <util/list.h>

#include <fs/select_sync_pool.h>
#include <kernel.h>

#include <net_protocol.h>
#include <net_stack.h>
#include <net_stat.h>


struct net_socket_private : net_socket {
	struct list_link		link;
	team_id					owner;
	uint32					max_backlog;
	uint32					child_count;
	struct list				pending_children;
	struct list				connected_children;

	struct select_sync_pool	*select_pool;
	benaphore				lock;
};


void socket_delete(net_socket *socket);
int socket_bind(net_socket *socket, const struct sockaddr *address,
	socklen_t addressLength);
int socket_setsockopt(net_socket *socket, int level, int option,
	const void *value, int length);


struct list sSocketList;
benaphore sSocketLock;


static size_t
compute_user_iovec_length(iovec *userVec, uint32 count)
{
	size_t length = 0;

	for (uint32 i = 0; i < count; i++) {
		iovec vec;
		if (user_memcpy(&vec, userVec + i, sizeof(iovec)) < B_OK)
			return 0;

		length += vec.iov_len;
	}

	return length;
}


static void
delete_children(struct list *list)
{
	while (true) {
		net_socket_private *child
			= (net_socket_private *)list_remove_head_item(list);
		if (child == NULL)
			break;

		child->parent = NULL;
		socket_delete(child);
	}
}


static status_t
create_socket(int family, int type, int protocol, net_socket_private **_socket)
{
	struct net_socket_private *socket = new (std::nothrow) net_socket_private;
	if (socket == NULL)
		return B_NO_MEMORY;

	memset(socket, 0, sizeof(net_socket_private));
	socket->family = family;
	socket->type = type;
	socket->protocol = protocol;

	status_t status = benaphore_init(&socket->lock, "socket");
	if (status < B_OK)
		goto err1;

	// set defaults (may be overridden by the protocols)
	socket->send.buffer_size = 65535;
	socket->send.low_water_mark = 1;
	socket->send.timeout = B_INFINITE_TIMEOUT;
	socket->receive.buffer_size = 65535;
	socket->receive.low_water_mark = 1;
	socket->receive.timeout = B_INFINITE_TIMEOUT;

	list_init_etc(&socket->pending_children, offsetof(net_socket_private,
		link));
	list_init_etc(&socket->connected_children, offsetof(net_socket_private,
		link));

	status = get_domain_protocols(socket);
	if (status < B_OK)
		goto err2;

	*_socket = socket;
	return B_OK;

err2:
	benaphore_destroy(&socket->lock);
err1:
	delete socket;
	return status;
}


//	#pragma mark -


status_t
socket_open(int family, int type, int protocol, net_socket **_socket)
{
	net_socket_private *socket;
	status_t status = create_socket(family, type, protocol, &socket);
	if (status < B_OK)
		return status;
	
	status = socket->first_info->open(socket->first_protocol);
	if (status < B_OK) {
		socket_delete(socket);
		return status;
	}

	socket->owner = team_get_current_team_id();

	benaphore_lock(&sSocketLock);
	list_add_item(&sSocketList, socket);
	benaphore_unlock(&sSocketLock);

	*_socket = socket;
	return B_OK;
}


status_t
socket_close(net_socket *_socket)
{
	net_socket_private *socket = (net_socket_private *)_socket;

	if (socket->select_pool) {
		// notify all pending selects
		notify_select_event_pool(socket->select_pool, ~0);
	}

	return socket->first_info->close(socket->first_protocol);
}


status_t
socket_free(net_socket *socket)
{
	status_t status = socket->first_info->free(socket->first_protocol);
	if (status == B_BUSY)
		return B_OK;

	socket_delete(socket);
	return B_OK;
}


status_t
socket_readv(net_socket *socket, const iovec *vecs, size_t vecCount,
	size_t *_length)
{
	return -1;
}


status_t
socket_writev(net_socket *socket, const iovec *vecs, size_t vecCount,
	size_t *_length)
{
	if (socket->peer.ss_len == 0)
		return ECONNRESET;

	if (socket->address.ss_len == 0) {
		// try to bind first
		status_t status = socket_bind(socket, NULL, 0);
		if (status < B_OK)
			return status;
	}

	// TODO: useful, maybe even computed header space!
	net_buffer *buffer = gNetBufferModule.create(256);
	if (buffer == NULL)
		return ENOBUFS;

	// copy data into buffer

	for (uint32 i = 0; i < vecCount; i++) {
		if (gNetBufferModule.append(buffer, vecs[i].iov_base,
				vecs[i].iov_len) < B_OK) {
			gNetBufferModule.free(buffer);
			return ENOBUFS;
		}
	}

	memcpy(buffer->source, &socket->address, socket->address.ss_len);
	memcpy(buffer->destination, &socket->peer, socket->peer.ss_len);
	size_t size = buffer->size;

	ssize_t bytesWritten = socket->first_info->send_data(socket->first_protocol,
		buffer);
	if (bytesWritten < B_OK) {
		if (buffer->size != size) {
			// this appears to be a partial write
			*_length = size - buffer->size;
		}
		gNetBufferModule.free(buffer);
		return bytesWritten;
	}

	*_length = bytesWritten;
	return B_OK;
}


status_t
socket_control(net_socket *socket, int32 op, void *data, size_t length,
	bool kernel)
{
	switch (op) {
		case FIONBIO:
		{
			if (data == NULL)
				return B_BAD_VALUE;

			int value;
			if (kernel) {
				value = *(int*)data;
			} else {
				if (!IS_USER_ADDRESS(data)
					|| user_memcpy(&value, data, sizeof(int)) != B_OK) {
					return B_BAD_ADDRESS;
				}
			}
			return socket_setsockopt(socket, SOL_SOCKET, SO_NONBLOCK, &value,
				sizeof(int));
		}

		case B_SET_BLOCKING_IO:
		case B_SET_NONBLOCKING_IO:
		{
			int value = op == B_SET_NONBLOCKING_IO;
			return socket_setsockopt(socket, SOL_SOCKET, SO_NONBLOCK, &value,
				sizeof(int));
		}
	}

	return socket->first_info->control(socket->first_protocol,
		LEVEL_DRIVER_IOCTL, op, data, &length);
}


ssize_t
socket_read_avail(net_socket *socket)
{
	return socket->first_info->read_avail(socket->first_protocol);
}


ssize_t
socket_send_avail(net_socket *socket)
{
	return socket->first_info->send_avail(socket->first_protocol);
}


status_t
socket_send_data(net_socket *socket, net_buffer *buffer)
{
	return socket->first_info->send_data(socket->first_protocol,
		buffer);
}


status_t
socket_receive_data(net_socket *socket, size_t length, uint32 flags,
	net_buffer **_buffer)
{
	status_t status = socket->first_info->read_data(socket->first_protocol,
		length, flags, _buffer);

	if (status < B_OK)
		return status;

	if (*_buffer && length < (*_buffer)->size) {
		// discard any data behind the amount requested
		gNetBufferModule.trim(*_buffer, length);
	}

	return status;
}


status_t
socket_get_next_stat(uint32 *_cookie, int family, struct net_stat *stat)
{
	BenaphoreLocker locker(sSocketLock);

	net_socket_private *socket = NULL;
	uint32 cookie = *_cookie;
	uint32 count = 0;
	while ((socket = (net_socket_private *)list_get_next_item(&sSocketList,
			socket)) != NULL) {
		// TODO: also traverse the pending connections
		if (count == cookie)
			break;

		if (family == -1 || family == socket->family)
			count++;
	}

	if (socket == NULL)
		return B_ENTRY_NOT_FOUND;

	*_cookie = count + 1;

	stat->family = socket->family;
	stat->type = socket->type;
	stat->protocol = socket->protocol;
	stat->owner = socket->owner;
	stat->state[0] = '\0';
	memcpy(&stat->address, &socket->address, sizeof(struct sockaddr_storage));
	memcpy(&stat->peer, &socket->peer, sizeof(struct sockaddr_storage));
	stat->receive_queue_size = 0;
	stat->send_queue_size = 0;

	// fill in protocol specific data (if supported by the protocol)
	size_t length = sizeof(net_stat);
	socket->first_info->control(socket->first_protocol, socket->protocol,
		NET_STAT_SOCKET, stat, &length);

	return B_OK;
}


//	#pragma mark - connections


status_t
socket_spawn_pending(net_socket *_parent, net_socket **_socket)
{
	net_socket_private *parent = (net_socket_private *)_parent;

	BenaphoreLocker locker(parent->lock);

	// We actually accept more pending connections to compensate for those
	// that never complete, and also make sure at least a single connection
	// can always be accepted
	if (parent->child_count > 3 * parent->max_backlog / 2)
		return ENOBUFS;

	net_socket_private *socket;
	status_t status = create_socket(parent->family, parent->type,
		parent->protocol, &socket);
	if (status < B_OK)
		return status;

	// inherit parent's properties
	socket->send = parent->send;
	socket->receive = parent->receive;
	socket->options = parent->options & ~SO_ACCEPTCONN;
	socket->linger = parent->linger;
	socket->owner = parent->owner;
	memcpy(&socket->address, &parent->address, parent->address.ss_len);
	memcpy(&socket->peer, &parent->peer, parent->peer.ss_len);

	// add to the parent's list of pending connections
	list_add_item(&parent->pending_children, socket);
	socket->parent = parent;
	parent->child_count++;

	*_socket = socket;
	return B_OK;
}


void
socket_delete(net_socket *_socket)
{
	net_socket_private *socket = (net_socket_private *)_socket;

	if (socket->parent != NULL)
		panic("socket still has a parent!");

	benaphore_lock(&sSocketLock);
	list_remove_item(&sSocketList, socket);
	benaphore_unlock(&sSocketLock);

	// also delete all children of this socket
	delete_children(&socket->pending_children);
	delete_children(&socket->connected_children);

	put_domain_protocols(socket);
	benaphore_destroy(&socket->lock);
	delete_select_sync_pool(socket->select_pool);
	delete socket;
}


status_t
socket_dequeue_connected(net_socket *_parent, net_socket **_socket)
{
	net_socket_private *parent = (net_socket_private *)_parent;

	benaphore_lock(&parent->lock);

	net_socket_private *socket = (net_socket_private *)list_remove_head_item(
		&parent->connected_children);
	if (socket != NULL) {
		socket->parent = NULL;
		parent->child_count--;
		*_socket = socket;
	}

	benaphore_unlock(&parent->lock);

	if (socket == NULL)
		return B_ENTRY_NOT_FOUND;

	benaphore_lock(&sSocketLock);
	list_add_item(&sSocketList, socket);
	benaphore_unlock(&sSocketLock);

	return B_OK;
}


ssize_t
socket_count_connected(net_socket *_parent)
{
	net_socket_private *parent = (net_socket_private *)_parent;

	BenaphoreLocker _(parent->lock);

	ssize_t count = 0;
	void *item = NULL;
	while ((item = list_get_next_item(&parent->connected_children,
			item)) != NULL) {
		count++;
	}

	return count;
}


status_t
socket_set_max_backlog(net_socket *_socket, uint32 backlog)
{
	net_socket_private *socket = (net_socket_private *)_socket;

	// we enforce an upper limit of connections waiting to be accepted
	if (backlog > 256)
		backlog = 256;

	benaphore_lock(&socket->lock);

	// first remove the pending connections, then the already connected
	// ones as needed	
	net_socket_private *child;
	while (socket->child_count > backlog
		&& (child = (net_socket_private *)list_remove_tail_item(
				&socket->pending_children)) != NULL) {
		child->parent = NULL;
		socket->child_count--;
	}
	while (socket->child_count > backlog
		&& (child = (net_socket_private *)list_remove_tail_item(
				&socket->connected_children)) != NULL) {
		child->parent = NULL;
		socket_delete(child);
		socket->child_count--;
	}

	socket->max_backlog = backlog;
	benaphore_unlock(&socket->lock);
	return B_OK;
}


/*!
	The socket has been connected. It will be moved to the connected queue
	of its parent socket.
*/
status_t
socket_connected(net_socket *socket)
{
	net_socket_private *parent = (net_socket_private *)socket->parent;
	if (parent == NULL)
		return B_BAD_VALUE;

	benaphore_lock(&parent->lock);

	list_remove_item(&parent->pending_children, socket);
	list_add_item(&parent->connected_children, socket);

	// notify parent
	if (parent->select_pool)
		notify_select_event_pool(parent->select_pool, B_SELECT_READ);

	benaphore_unlock(&parent->lock);
	return B_OK;
}


//	#pragma mark - notifications


status_t
socket_request_notification(net_socket *_socket, uint8 event, selectsync *sync)
{
	net_socket_private *socket = (net_socket_private *)_socket;

	benaphore_lock(&socket->lock);

	status_t status = add_select_sync_pool_entry(&socket->select_pool, sync,
		event);

	benaphore_unlock(&socket->lock);

	if (status < B_OK)
		return status;

	// check if the event is already present
	// TODO: add support for poll() types

	switch (event) {
		case B_SELECT_READ:
		{
			ssize_t available = socket_read_avail(socket);
			if ((ssize_t)socket->receive.low_water_mark <= available
				|| available < B_OK)
				notify_select_event(sync, event);
			break;
		}
		case B_SELECT_WRITE:
		{
			ssize_t available = socket_send_avail(socket);
			if ((ssize_t)socket->send.low_water_mark <= available
				|| available < B_OK)
				notify_select_event(sync, event);
			break;
		}
		case B_SELECT_ERROR:
			// TODO: B_SELECT_ERROR condition!
			break;
	}

	return B_OK;
}


status_t
socket_cancel_notification(net_socket *_socket, uint8 event, selectsync *sync)
{
	net_socket_private *socket = (net_socket_private *)_socket;

	benaphore_lock(&socket->lock);

	status_t status = remove_select_sync_pool_entry(&socket->select_pool,
		sync, event);

	benaphore_unlock(&socket->lock);
	return status;
}


status_t
socket_notify(net_socket *_socket, uint8 event, int32 value)
{
	net_socket_private *socket = (net_socket_private *)_socket;
	bool notify = true;

	switch (event) {
		case B_SELECT_READ:
			if ((ssize_t)socket->receive.low_water_mark > value
				&& value >= B_OK)
				notify = false;
			break;

		case B_SELECT_WRITE:
			if ((ssize_t)socket->send.low_water_mark > value
				&& value >= B_OK)
				notify = false;
			break;

		case B_SELECT_ERROR:
			socket->error = value;
			break;
	}

	benaphore_lock(&socket->lock);

	if (notify && socket->select_pool)
		notify_select_event_pool(socket->select_pool, event);

	benaphore_unlock(&socket->lock);
	return B_OK;
}


//	#pragma mark - standard socket API


int
socket_accept(net_socket *socket, struct sockaddr *address,
	socklen_t *_addressLength, net_socket **_acceptedSocket)
{
	if ((socket->options & SO_ACCEPTCONN) == 0)
		return B_BAD_VALUE;

	net_socket *accepted;
	status_t status = socket->first_info->accept(socket->first_protocol,
		&accepted);
	if (status < B_OK)
		return status;

	if (address && *_addressLength > 0) {
		memcpy(address, &accepted->peer, min_c(*_addressLength,
			min_c(accepted->peer.ss_len, sizeof(sockaddr_storage))));
		*_addressLength = accepted->peer.ss_len;
	}

	*_acceptedSocket = accepted;
	return B_OK;
}


int
socket_bind(net_socket *socket, const struct sockaddr *address,
	socklen_t addressLength)
{
	sockaddr empty;
	if (address == NULL) {
		// special - try to bind to an empty address, like INADDR_ANY
		memset(&empty, 0, sizeof(sockaddr));
		empty.sa_len = sizeof(sockaddr);
		empty.sa_family = socket->family;

		address = &empty;
		addressLength = sizeof(sockaddr);
	}

	if (socket->address.ss_len != 0) {
		status_t status = socket->first_info->unbind(socket->first_protocol,
			(sockaddr *)&socket->address);
		if (status < B_OK)
			return status;
	}

	memcpy(&socket->address, address, sizeof(sockaddr));

	status_t status = socket->first_info->bind(socket->first_protocol, 
		(sockaddr *)address);
	if (status < B_OK) {
		// clear address again, as binding failed
		socket->address.ss_len = 0;
	}

	return status;
}


int
socket_connect(net_socket *socket, const struct sockaddr *address,
	socklen_t addressLength)
{
	if (address == NULL || addressLength == 0)
		return ENETUNREACH;

	if (socket->address.ss_len == 0) {
		// try to bind first
		status_t status = socket_bind(socket, NULL, 0);
		if (status < B_OK)
			return status;
	}

	return socket->first_info->connect(socket->first_protocol, address);
}


int
socket_getpeername(net_socket *socket, struct sockaddr *address,
	socklen_t *_addressLength)
{
	if (socket->peer.ss_len == 0)
		return ENOTCONN;

	memcpy(address, &socket->peer, min_c(*_addressLength, socket->peer.ss_len));
	*_addressLength = socket->peer.ss_len;
	return B_OK;
}


int
socket_getsockname(net_socket *socket, struct sockaddr *address,
	socklen_t *_addressLength)
{
	if (socket->address.ss_len == 0)
		return ENOTCONN;

	memcpy(address, &socket->address, min_c(*_addressLength,
		socket->address.ss_len));
	*_addressLength = socket->address.ss_len;
	return B_OK;
}


status_t
socket_get_option(net_socket *socket, int level, int option, void *value,
	int *_length)
{
	if (level != SOL_SOCKET)
		return ENOPROTOOPT;

	switch (option) {
		case SO_SNDBUF:
		{
			uint32 *size = (uint32 *)value;
			*size = socket->send.buffer_size;
			*_length = sizeof(uint32);
			return B_OK;
		}

		case SO_RCVBUF:
		{
			uint32 *size = (uint32 *)value;
			*size = socket->receive.buffer_size;
			*_length = sizeof(uint32);
			return B_OK;
		}

		case SO_SNDLOWAT:
		{
			uint32 *size = (uint32 *)value;
			*size = socket->send.low_water_mark;
			*_length = sizeof(uint32);
			return B_OK;
		}

		case SO_RCVLOWAT:
		{
			uint32 *size = (uint32 *)value;
			*size = socket->receive.low_water_mark;
			*_length = sizeof(uint32);
			return B_OK;
		}

		case SO_RCVTIMEO:
		case SO_SNDTIMEO:
		{
			if (*_length < (int)sizeof(struct timeval))
				return B_BAD_VALUE;

			bigtime_t timeout;
			if (option == SO_SNDTIMEO)
				timeout = socket->send.timeout;
			else
				timeout = socket->receive.timeout;
			if (timeout == B_INFINITE_TIMEOUT)
				timeout = 0;

			struct timeval *timeval = (struct timeval *)value;
			timeval->tv_sec = timeout / 1000000LL;
			timeval->tv_usec = timeout % 1000000LL;

			*_length = sizeof(struct timeval);
			return B_OK;
		}

		case SO_NONBLOCK:
		{
			int32 *_set = (int32 *)value;
			*_set = socket->receive.timeout == 0 && socket->send.timeout == 0;
			*_length = sizeof(int32);
			return B_OK;
		}

		case SO_ACCEPTCONN:
		case SO_BROADCAST:
		case SO_DEBUG:
		case SO_DONTROUTE:
		case SO_KEEPALIVE:
		case SO_OOBINLINE:
		case SO_REUSEADDR:
		case SO_REUSEPORT:
		case SO_USELOOPBACK:
		{
			int32 *_set = (int32 *)value;
			*_set = (socket->options & option) != 0;
			*_length = sizeof(int32);
			return B_OK;
		}

		case SO_ERROR:
		{
			int32 *_set = (int32 *)value;
			*_set = socket->error;
			*_length = sizeof(int32);

			socket->error = B_OK;
				// clear error upon retrieval
			return B_OK;
		}

		default:
			break;
	}

	dprintf("socket_getsockopt: unknown option %d\n", option);
	return ENOPROTOOPT;
}


int
socket_getsockopt(net_socket *socket, int level, int option, void *value,
	int *_length)
{
	return socket->first_protocol->module->getsockopt(socket->first_protocol,
		level, option, value, _length);
}


int
socket_listen(net_socket *socket, int backlog)
{
	status_t status = socket->first_info->listen(socket->first_protocol,
		backlog);
	if (status == B_OK)
		socket->options |= SO_ACCEPTCONN;

	return status;
}


ssize_t
socket_receive(net_socket *socket, msghdr *header, void *data, size_t length,
	int flags)
{
	size_t totalLength = length;
	net_buffer *buffer;
	iovec tmp;
	int i;

	// the convention to this function is that have header been
	// present, { data, length } would have been iovec[0] and is
	// always considered like that

	if (header) {
		// calculate the length considering all of the extra buffers
		for (i = 1; i < header->msg_iovlen; i++) {
			if (user_memcpy(&tmp, header->msg_iov + i, sizeof(iovec)) < B_OK)
				return B_BAD_ADDRESS;
			if (tmp.iov_len > 0 && tmp.iov_base == NULL)
				return B_BAD_ADDRESS;
			totalLength += tmp.iov_len;
		}
	}

	status_t status = socket->first_info->read_data(
		socket->first_protocol, totalLength, flags, &buffer);
	if (status < B_OK)
		return status;

	// TODO: - returning a NULL buffer when received 0 bytes
	//         may not make much sense as we still need the address
	//       - gNetBufferModule.read() uses memcpy() instead of user_memcpy

	size_t nameLen = 0;

	if (header) {
		// TODO: - consider the control buffer options
		nameLen = header->msg_namelen;
		header->msg_namelen = 0;
		header->msg_flags = 0;
	}

	if (buffer == NULL)
		return 0;

	size_t bytesReceived = buffer->size, bytesCopied = 0;

	length = min_c(bytesReceived, length);
	if (gNetBufferModule.read(buffer, 0, data, length) < B_OK) {
		gNetBufferModule.free(buffer);
		return ENOBUFS;
	}

	// if first copy was a success, proceed to following
	// copies as required
	bytesCopied += length;

	if (header) {
		// we only start considering at iovec[1]
		// as { data, length } is iovec[0]
		for (i = 1; i < header->msg_iovlen && bytesCopied < bytesReceived; i++) {
			if (user_memcpy(&tmp, header->msg_iov + i, sizeof(iovec)) < B_OK)
				break;

			size_t toRead = min_c(bytesReceived - bytesCopied, tmp.iov_len);
			if (gNetBufferModule.read(buffer, bytesCopied, tmp.iov_base,
										toRead) < B_OK)
				break;

			bytesCopied += toRead;
		}

		if (header->msg_name != NULL) {
			header->msg_namelen = min_c(nameLen, buffer->source->sa_len);
			memcpy(header->msg_name, buffer->source, header->msg_namelen);
		}
	}

	gNetBufferModule.free(buffer);

	if (bytesCopied < bytesReceived) {
		if (header)
			header->msg_flags = MSG_TRUNC;

		if (flags & MSG_TRUNC)
			return bytesReceived;
	}

	return bytesCopied;
}


ssize_t
socket_send(net_socket *socket, msghdr *header, const void *data, size_t length,
	int flags)
{
	const sockaddr *address = NULL;
	socklen_t addressLength = 0;
	size_t bytesLeft = length;

	if (length > SSIZE_MAX)
		return B_BAD_VALUE;

	// the convention to this function is that have header been
	// present, { data, length } would have been iovec[0] and is
	// always considered like that

	if (header != NULL) {
		address = (const sockaddr *)header->msg_name;
		addressLength = header->msg_namelen;

		if (header->msg_iovlen <= 1)
			header = NULL;
		else {
			bytesLeft += compute_user_iovec_length(header->msg_iov + 1,
				header->msg_iovlen - 1);
		}
	}

	if (addressLength == 0)
		address = NULL;
	else if (addressLength != 0 && address == NULL)
		return B_BAD_VALUE;

	if (socket->peer.ss_len != 0) {
		if (address != NULL)
			return EISCONN;

		// socket is connected, we use that address
		address = (struct sockaddr *)&socket->peer;
		addressLength = socket->peer.ss_len;
	}

	if (address == NULL || addressLength == 0) {
		// don't know where to send to:
		return EDESTADDRREQ;
	}

	if ((socket->first_info->flags & NET_PROTOCOL_ATOMIC_MESSAGES) != 0
		&& bytesLeft > socket->send.buffer_size)
		return EMSGSIZE;

	if (socket->address.ss_len == 0) {
		// try to bind first
		status_t status = socket_bind(socket, NULL, 0);
		if (status < B_OK)
			return status;
	}

	ssize_t bytesSent = 0;
	size_t vecOffset = 0;
	uint32 vecIndex = 0;

	while (bytesLeft > 0) {
		// TODO: useful, maybe even computed header space!
		net_buffer *buffer = gNetBufferModule.create(256);
		if (buffer == NULL)
			return ENOBUFS;

		while (buffer->size < socket->send.buffer_size
			&& buffer->size < bytesLeft) {
			if (vecIndex > 0 && vecOffset == 0) {
				// retrieve next iovec buffer from header
				iovec vec;
				if (user_memcpy(&vec, header->msg_iov + vecIndex, sizeof(iovec))
						< B_OK) {
					gNetBufferModule.free(buffer);
					return B_BAD_ADDRESS;
				}

				data = vec.iov_base;
				length = vec.iov_len;
			}

			size_t bytes = length;
			if (buffer->size + bytes > socket->send.buffer_size)
				bytes = socket->send.buffer_size - buffer->size;

			if (gNetBufferModule.append(buffer, data, bytes) < B_OK) {
				gNetBufferModule.free(buffer);
				return ENOBUFS;
			}

			if (bytes != length) {
				// partial send
				vecOffset = bytes;
				length -= vecOffset;
				data = (uint8 *)data + vecOffset;
			} else if (header != NULL) {
				// proceed with next buffer, if any
				vecOffset = 0;
				vecIndex++;

				if (vecIndex >= (uint32)header->msg_iovlen)
					break;
			}
		}

		size_t bufferSize = buffer->size;
		buffer->flags = flags;
		memcpy(buffer->source, &socket->address, socket->address.ss_len);
		memcpy(buffer->destination, address, addressLength);

		status_t status = socket->first_info->send_data(socket->first_protocol,
			buffer);
		if (status < B_OK) {
			size_t sizeAfterSend = buffer->size;
			gNetBufferModule.free(buffer);

			if (sizeAfterSend != bufferSize
				&& (status == B_INTERRUPTED || status == B_WOULD_BLOCK)) {
				// this appears to be a partial write
				return bytesSent + (bufferSize - sizeAfterSend);
			}
			return status;
		}

		bytesLeft -= bufferSize;
		bytesSent += bufferSize;
	}

	return bytesSent;
}


status_t
socket_set_option(net_socket *socket, int level, int option, const void *value,
	int length)
{
	if (level != SOL_SOCKET)
		return ENOPROTOOPT;

	switch (option) {
		// TODO: implement other options!
		case SO_LINGER:
		{
			if (length < (int)sizeof(struct linger))
				return B_BAD_VALUE;

			struct linger *linger = (struct linger *)value;
			if (linger->l_onoff) {
				socket->options |= SO_LINGER;
				socket->linger = linger->l_linger;
			} else {
				socket->options &= ~SO_LINGER;
				socket->linger = 0;
			}
			return B_OK;
		}

		case SO_SNDBUF:
			if (length != sizeof(uint32))
				return B_BAD_VALUE;

			socket->send.buffer_size = *(const uint32 *)value;
			return B_OK;

		case SO_RCVBUF:
			if (length != sizeof(uint32))
				return B_BAD_VALUE;

			socket->receive.buffer_size = *(const uint32 *)value;
			return B_OK;

		case SO_SNDLOWAT:
			if (length != sizeof(uint32))
				return B_BAD_VALUE;

			socket->send.low_water_mark = *(const uint32 *)value;
			return B_OK;

		case SO_RCVLOWAT:
			if (length != sizeof(uint32))
				return B_BAD_VALUE;

			socket->receive.low_water_mark = *(const uint32 *)value;
			return B_OK;

		case SO_RCVTIMEO:
		case SO_SNDTIMEO:
		{
			if (length != sizeof(struct timeval))
				return B_BAD_VALUE;

			const struct timeval *timeval = (const struct timeval *)value;
			bigtime_t timeout = timeval->tv_sec * 1000000LL + timeval->tv_usec;
			if (timeout == 0)
				timeout = B_INFINITE_TIMEOUT;

			if (option == SO_SNDTIMEO)
				socket->send.timeout = timeout;
			else
				socket->receive.timeout = timeout;
			return B_OK;
		}

		case SO_NONBLOCK:
			if (length != sizeof(int32))
				return B_BAD_VALUE;

			if (*(const int32 *)value) {
				socket->send.timeout = 0;
				socket->receive.timeout = 0;
			} else {
				socket->send.timeout = B_INFINITE_TIMEOUT;
				socket->receive.timeout = B_INFINITE_TIMEOUT;
			}
			return B_OK;

		case SO_BROADCAST:
		case SO_DEBUG:
		case SO_DONTROUTE:
		case SO_KEEPALIVE:
		case SO_OOBINLINE:
		case SO_REUSEADDR:
		case SO_REUSEPORT:
		case SO_USELOOPBACK:
			if (length != sizeof(int32))
				return B_BAD_VALUE;

			if (*(const int32 *)value)
				socket->options |= option;
			else
				socket->options &= ~option;
			return B_OK;

		default:
			break;
	}

	dprintf("socket_setsockopt: unknown option %d\n", option);
	return ENOPROTOOPT;
}


int
socket_setsockopt(net_socket *socket, int level, int option, const void *value,
	int length)
{
	return socket->first_protocol->module->setsockopt(socket->first_protocol,
		level, option, value, length);
}


int
socket_shutdown(net_socket *socket, int direction)
{
	return socket->first_info->shutdown(socket->first_protocol, direction);
}


status_t
socket_socketpair(int family, int type, int protocol, net_socket* sockets[2])
{
	sockets[0] = NULL;
	sockets[1] = NULL;

	// create sockets
	status_t error = socket_open(family, type, protocol, &sockets[0]);
	if (error != B_OK)
		return error;

	if (error == B_OK)
		error = socket_open(family, type, protocol, &sockets[1]);

	// bind one
	if (error == B_OK)
		error = socket_bind(sockets[0], NULL, 0);

	// start listening
	if (error == B_OK)
		error = socket_listen(sockets[0], 1);

	// connect them	
	if (error == B_OK) {
		error = socket_connect(sockets[1], (sockaddr*)&sockets[0]->address,
			sockets[0]->address.ss_len);
	}

	// accept a socket
	net_socket* acceptedSocket = NULL;
	if (error == B_OK)
		error = socket_accept(sockets[0], NULL, NULL, &acceptedSocket);

	if (error == B_OK) {
		// everything worked: close the listener socket
		socket_close(sockets[0]);
		socket_free(sockets[0]);
		sockets[0] = acceptedSocket;
	} else {
		// close sockets on error
		for (int i = 0; i < 2; i++) {
			if (sockets[i] != NULL) {
				socket_close(sockets[i]);
				socket_free(sockets[i]);
				sockets[i] = NULL;
			}
		}
	}

	return error;
}


//	#pragma mark -


static status_t
socket_std_ops(int32 op, ...)
{
	switch (op) {
		case B_MODULE_INIT:
		{
			// TODO: this is currently done in the net_stack driver
			// initialize the main stack if not done so already
			//module_info *module;
			//return get_module(NET_STARTER_MODULE_NAME, &module);
			list_init_etc(&sSocketList, offsetof(net_socket_private, link));
			return benaphore_init(&sSocketLock, "socket list");
		}
		case B_MODULE_UNINIT:
			//return put_module(NET_STARTER_MODULE_NAME);
			benaphore_destroy(&sSocketLock);
			return B_OK;

		default:
			return B_ERROR;
	}
}


net_socket_module_info gNetSocketModule = {
	{
		NET_SOCKET_MODULE_NAME,
		0,
		socket_std_ops
	},
	socket_open,
	socket_close,
	socket_free,

	socket_readv,
	socket_writev,
	socket_control,

	socket_read_avail,
	socket_send_avail,

	socket_send_data,
	socket_receive_data,

	socket_get_option,
	socket_set_option,

	socket_get_next_stat,

	// connections
	socket_spawn_pending,
	socket_delete,
	socket_dequeue_connected,
	socket_count_connected,
	socket_set_max_backlog,
	socket_connected,

	// notifications
	socket_request_notification,
	socket_cancel_notification,
	socket_notify,

	// standard socket API
	socket_accept,
	socket_bind,
	socket_connect,
	socket_getpeername,
	socket_getsockname,
	socket_getsockopt,
	socket_listen,
	socket_receive,
	socket_send,
	socket_setsockopt,
	socket_shutdown,
	socket_socketpair
};