/** 
 * @file lliosocket.cpp
 * @author Phoenix
 * @date 2005-07-31
 * @brief Sockets declarations for use with the io pipes
 *
 * $LicenseInfo:firstyear=2005&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "linden_common.h"
#include "lliosocket.h"

#include "llapr.h"

#include "llbuffer.h"
#include "llfasttimer.h"
#include "llhost.h"
#include "llpumpio.h"

//
// constants
//

static const S32 LL_DEFAULT_LISTEN_BACKLOG = 10;
static const S32 LL_SEND_BUFFER_SIZE = 40000;
static const S32 LL_RECV_BUFFER_SIZE = 40000;
//static const U16 LL_PORT_DISCOVERY_RANGE_MIN = 13000;
//static const U16 LL_PORT_DISCOVERY_RANGE_MAX = 13050;

//
// local methods 
//

bool is_addr_in_use(apr_status_t status)
{
#if LL_WINDOWS
	return (WSAEADDRINUSE == APR_TO_OS_ERROR(status));
#else
	return (EADDRINUSE == APR_TO_OS_ERROR(status));
#endif
}

#if LL_LINUX
// Define this to see the actual file descriptors being tossed around.
//#define LL_DEBUG_SOCKET_FILE_DESCRIPTORS 1
#if LL_DEBUG_SOCKET_FILE_DESCRIPTORS
#include "apr_portable.h"
#endif
#endif


// Quick function 
void ll_debug_socket(const char* msg, apr_socket_t* apr_sock)
{
#if LL_DEBUG_SOCKET_FILE_DESCRIPTORS
	if(!apr_sock)
	{
		lldebugs << "Socket -- " << (msg?msg:"") << ": no socket." << llendl;
		return;
	}
	// *TODO: Why doesn't this work?
	//apr_os_sock_t os_sock;
	int os_sock;
	if(APR_SUCCESS == apr_os_sock_get(&os_sock, apr_sock))
	{
		lldebugs << "Socket -- " << (msg?msg:"") << " on fd " << os_sock
			<< " at " << apr_sock << llendl;
	}
	else
	{
		lldebugs << "Socket -- " << (msg?msg:"") << " no fd "
			<< " at " << apr_sock << llendl;
	}
#endif
}

///
/// LLSocket
///

// static
LLSocket::ptr_t LLSocket::create(apr_pool_t* pool, EType type, U16 port)
{
	LLSocket::ptr_t rv;
	apr_socket_t* socket = NULL;
	apr_pool_t* new_pool = NULL;
	apr_status_t status = APR_EGENERAL;

	// create a pool for the socket
	status = apr_pool_create(&new_pool, pool);
	if(ll_apr_warn_status(status))
	{
		if(new_pool) apr_pool_destroy(new_pool);
		return rv;
	}

	if(STREAM_TCP == type)
	{
		status = apr_socket_create(
			&socket,
			APR_INET,
			SOCK_STREAM,
			APR_PROTO_TCP,
			new_pool);
	}
	else if(DATAGRAM_UDP == type)
	{
		status = apr_socket_create(
			&socket,
			APR_INET,
			SOCK_DGRAM,
			APR_PROTO_UDP,
			new_pool);
	}
	else
	{
		if(new_pool) apr_pool_destroy(new_pool);
		return rv;
	}
	if(ll_apr_warn_status(status))
	{
		if(new_pool) apr_pool_destroy(new_pool);
		return rv;
	}
	rv = ptr_t(new LLSocket(socket, new_pool));
	if(port > 0)
	{
		apr_sockaddr_t* sa = NULL;
		status = apr_sockaddr_info_get(
			&sa,
			APR_ANYADDR,
			APR_UNSPEC,
			port,
			0,
			new_pool);
		if(ll_apr_warn_status(status))
		{
			rv.reset();
			return rv;
		}
		// This allows us to reuse the address on quick down/up. This
		// is unlikely to create problems.
		ll_apr_warn_status(apr_socket_opt_set(socket, APR_SO_REUSEADDR, 1));
		status = apr_socket_bind(socket, sa);
		if(ll_apr_warn_status(status))
		{
			rv.reset();
			return rv;
		}
		lldebugs << "Bound " << ((DATAGRAM_UDP == type) ? "udp" : "tcp")
				 << " socket to port: " << sa->port << llendl;
		if(STREAM_TCP == type)
		{
			// If it's a stream based socket, we need to tell the OS
			// to keep a queue of incoming connections for ACCEPT.
			lldebugs << "Setting listen state for socket." << llendl;
			status = apr_socket_listen(
				socket,
				LL_DEFAULT_LISTEN_BACKLOG);
			if(ll_apr_warn_status(status))
			{
				rv.reset();
				return rv;
			}
		}
	}
	else
	{
		// we need to indicate that we have an ephemeral port if the
		// previous calls were successful. It will
		port = PORT_EPHEMERAL;
	}
	rv->mPort = port;
	rv->setNonBlocking();
	return rv;
}

// static
LLSocket::ptr_t LLSocket::create(apr_socket_t* socket, apr_pool_t* pool)
{
	LLSocket::ptr_t rv;
	if(!socket)
	{
		return rv;
	}
	rv = ptr_t(new LLSocket(socket, pool));
	rv->mPort = PORT_EPHEMERAL;
	rv->setNonBlocking();
	return rv;
}


bool LLSocket::blockingConnect(const LLHost& host)
{
	if(!mSocket) return false;
	apr_sockaddr_t* sa = NULL;
	std::string ip_address;
	ip_address = host.getIPString();
	if(ll_apr_warn_status(apr_sockaddr_info_get(
		&sa,
		ip_address.c_str(),
		APR_UNSPEC,
		host.getPort(),
		0,
		mPool)))
	{
		return false;
	}
	setBlocking(1000);
	ll_debug_socket("Blocking connect", mSocket);
	if(ll_apr_warn_status(apr_socket_connect(mSocket, sa))) return false;
	setNonBlocking();
	return true;
}

LLSocket::LLSocket(apr_socket_t* socket, apr_pool_t* pool) :
	mSocket(socket),
	mPool(pool),
	mPort(PORT_INVALID)
{
	ll_debug_socket("Constructing wholely formed socket", mSocket);
}

LLSocket::~LLSocket()
{
	// *FIX: clean up memory we are holding.
	if(mSocket)
	{
		ll_debug_socket("Destroying socket", mSocket);
		apr_socket_close(mSocket);
		mSocket = NULL;
	}
	if(mPool)
	{
		apr_pool_destroy(mPool);
	}
}

// See http://dev.ariel-networks.com/apr/apr-tutorial/html/apr-tutorial-13.html#ss13.4
// for an explanation of how to get non-blocking sockets and timeouts with
// consistent behavior across platforms.

void LLSocket::setBlocking(S32 timeout)
{
	// set up the socket options
	ll_apr_warn_status(apr_socket_timeout_set(mSocket, timeout));
	ll_apr_warn_status(apr_socket_opt_set(mSocket, APR_SO_NONBLOCK, 0));
	ll_apr_warn_status(apr_socket_opt_set(mSocket, APR_SO_SNDBUF, LL_SEND_BUFFER_SIZE));
	ll_apr_warn_status(apr_socket_opt_set(mSocket, APR_SO_RCVBUF, LL_RECV_BUFFER_SIZE));

}

void LLSocket::setNonBlocking()
{
	// set up the socket options
	ll_apr_warn_status(apr_socket_timeout_set(mSocket, 0));
	ll_apr_warn_status(apr_socket_opt_set(mSocket, APR_SO_NONBLOCK, 1));
	ll_apr_warn_status(apr_socket_opt_set(mSocket, APR_SO_SNDBUF, LL_SEND_BUFFER_SIZE));
	ll_apr_warn_status(apr_socket_opt_set(mSocket, APR_SO_RCVBUF, LL_RECV_BUFFER_SIZE));

}

///
/// LLIOSocketReader
///

LLIOSocketReader::LLIOSocketReader(LLSocket::ptr_t socket) :
	mSource(socket),
	mInitialized(false)
{
}

LLIOSocketReader::~LLIOSocketReader()
{
	//lldebugs << "Destroying LLIOSocketReader" << llendl;
}

static LLFastTimer::DeclareTimer FTM_PROCESS_SOCKET_READER("Socket Reader");

// virtual
LLIOPipe::EStatus LLIOSocketReader::process_impl(
	const LLChannelDescriptors& channels,
	buffer_ptr_t& buffer,
	bool& eos,
	LLSD& context,
	LLPumpIO* pump)
{
	LLFastTimer t(FTM_PROCESS_SOCKET_READER);
	PUMP_DEBUG;
	if(!mSource) return STATUS_PRECONDITION_NOT_MET;
	if(!mInitialized)
	{
		PUMP_DEBUG;
		// Since the read will not block, it's ok to initialize and
		// attempt to read off the descriptor immediately.
		mInitialized = true;
		if(pump)
		{
			PUMP_DEBUG;
			lldebugs << "Initializing poll descriptor for LLIOSocketReader."
					 << llendl;
			apr_pollfd_t poll_fd;
			poll_fd.p = NULL;
			poll_fd.desc_type = APR_POLL_SOCKET;
			poll_fd.reqevents = APR_POLLIN;
			poll_fd.rtnevents = 0x0;
			poll_fd.desc.s = mSource->getSocket();
			poll_fd.client_data = NULL;
			pump->setConditional(this, &poll_fd);
		}
	}
	//if(!buffer)
	//{
	//	buffer = new LLBufferArray;
	//}
	PUMP_DEBUG;
	const apr_size_t READ_BUFFER_SIZE = 1024;
	char read_buf[READ_BUFFER_SIZE]; /*Flawfinder: ignore*/
	apr_size_t len;
	apr_status_t status = APR_SUCCESS;
	do
	{
		PUMP_DEBUG;
		len = READ_BUFFER_SIZE;
		status = apr_socket_recv(mSource->getSocket(), read_buf, &len);
		buffer->append(channels.out(), (U8*)read_buf, len);
	} while((APR_SUCCESS == status) && (READ_BUFFER_SIZE == len));
	lldebugs << "socket read status: " << status << llendl;
	LLIOPipe::EStatus rv = STATUS_OK;

	PUMP_DEBUG;
	// *FIX: Also need to check for broken pipe
	if(APR_STATUS_IS_EOF(status))
	{
		// *FIX: Should we shut down the socket read?
		if(pump)
		{
			pump->setConditional(this, NULL);
		}
		rv = STATUS_DONE;
		eos = true;
	}
	else if(APR_STATUS_IS_EAGAIN(status))
	{
/*Commented out by Aura 9-9-8 for DEV-19961.
		// everything is fine, but we can terminate this process pump.
	
		rv = STATUS_BREAK;
*/
	}
	else
	{
		if(ll_apr_warn_status(status))
		{
			rv = STATUS_ERROR;
		}
	}
	PUMP_DEBUG;
	return rv;
}

///
/// LLIOSocketWriter
///

LLIOSocketWriter::LLIOSocketWriter(LLSocket::ptr_t socket) :
	mDestination(socket),
	mLastWritten(NULL),
	mInitialized(false)
{
}

LLIOSocketWriter::~LLIOSocketWriter()
{
	//lldebugs << "Destroying LLIOSocketWriter" << llendl;
}

static LLFastTimer::DeclareTimer FTM_PROCESS_SOCKET_WRITER("Socket Writer");
// virtual
LLIOPipe::EStatus LLIOSocketWriter::process_impl(
	const LLChannelDescriptors& channels,
	buffer_ptr_t& buffer,
	bool& eos,
	LLSD& context,
	LLPumpIO* pump)
{
	LLFastTimer t(FTM_PROCESS_SOCKET_WRITER);
	PUMP_DEBUG;
	if(!mDestination) return STATUS_PRECONDITION_NOT_MET;
	if(!mInitialized)
	{
		PUMP_DEBUG;
		// Since the write will not block, it's ok to initialize and
		// attempt to write immediately.
		mInitialized = true;
		if(pump)
		{
			PUMP_DEBUG;
			lldebugs << "Initializing poll descriptor for LLIOSocketWriter."
					 << llendl;
			apr_pollfd_t poll_fd;
			poll_fd.p = NULL;
			poll_fd.desc_type = APR_POLL_SOCKET;
			poll_fd.reqevents = APR_POLLOUT;
			poll_fd.rtnevents = 0x0;
			poll_fd.desc.s = mDestination->getSocket();
			poll_fd.client_data = NULL;
			pump->setConditional(this, &poll_fd);
		}
	}

	PUMP_DEBUG;
	// *FIX: Some sort of writev implementation would be much more
	// efficient - not only because writev() is better, but also
	// because we won't have to do as much work to find the start
	// address.
	buffer->lock();
	LLBufferArray::segment_iterator_t it;
	LLBufferArray::segment_iterator_t end = buffer->endSegment();
	LLSegment segment;
	it = buffer->constructSegmentAfter(mLastWritten, segment);
	/*
	if(NULL == mLastWritten)
	{
		it = buffer->beginSegment();
		segment = (*it);
	}
	else
	{
		it = buffer->getSegment(mLastWritten);
		segment = (*it);
		S32 size = segment.size();
		U8* data = segment.data();
		if((data + size) == mLastWritten)
		{
			++it;
			segment = (*it);
		}
		else
		{
			// *FIX: check the math on this one
			segment = LLSegment(
				(*it).getChannelMask(),
				mLastWritten + 1,
				size - (mLastWritten - data));
		}
	}
	*/

	PUMP_DEBUG;
	apr_size_t len;
	bool done = false;
	apr_status_t status = APR_SUCCESS;
	while(it != end)
	{

		PUMP_DEBUG;
		if((*it).isOnChannel(channels.in()))
		{
			PUMP_DEBUG;
			len = (apr_size_t)segment.size();
			status = apr_socket_send(
				mDestination->getSocket(),
				(const char*)segment.data(),
				&len);
			// We sometimes get a 'non-blocking socket operation could not be 
			// completed immediately' error from apr_socket_send.  In this
			// case we break and the data will be sent the next time the chain
			// is pumped.
			if(APR_STATUS_IS_EAGAIN(status))
			{
				ll_apr_warn_status(status);
				break;
			}

			mLastWritten = segment.data() + len - 1;

			PUMP_DEBUG;
			if((S32)len < segment.size())
			{
				break;
			}
			
		}

		++it;
		if(it != end)
		{
			segment = (*it);
		}
		else
		{
			done = true;
		}

	}
	buffer->unlock();

	PUMP_DEBUG;
	if(done && eos)
	{
		return STATUS_DONE;
	}
	return STATUS_OK;
}


///
/// LLIOServerSocket
///

LLIOServerSocket::LLIOServerSocket(
	apr_pool_t* pool,
	LLIOServerSocket::socket_t listener,
	factory_t factory) :
	mPool(pool),
	mListenSocket(listener),
	mReactor(factory),
	mInitialized(false),
	mResponseTimeout(DEFAULT_CHAIN_EXPIRY_SECS)
{
}

LLIOServerSocket::~LLIOServerSocket()
{
	//lldebugs << "Destroying LLIOServerSocket" << llendl;
}

void LLIOServerSocket::setResponseTimeout(F32 timeout_secs)
{
	mResponseTimeout = timeout_secs;
}

static LLFastTimer::DeclareTimer FTM_PROCESS_SERVER_SOCKET("Server Socket");
// virtual
LLIOPipe::EStatus LLIOServerSocket::process_impl(
	const LLChannelDescriptors& channels,
	buffer_ptr_t& buffer,
	bool& eos,
	LLSD& context,
	LLPumpIO* pump)
{
	LLFastTimer t(FTM_PROCESS_SERVER_SOCKET);
	PUMP_DEBUG;
	if(!pump)
	{
		llwarns << "Need a pump for server socket." << llendl;
		return STATUS_ERROR;
	}
	if(!mInitialized)
	{
		PUMP_DEBUG;
		// This segment sets up the pump so that we do not call
		// process again until we have an incoming read, aka connect()
		// from a remote host.
		lldebugs << "Initializing poll descriptor for LLIOServerSocket."
				 << llendl;
		apr_pollfd_t poll_fd;
		poll_fd.p = NULL;
		poll_fd.desc_type = APR_POLL_SOCKET;
		poll_fd.reqevents = APR_POLLIN;
		poll_fd.rtnevents = 0x0;
		poll_fd.desc.s = mListenSocket->getSocket();
		poll_fd.client_data = NULL;
		pump->setConditional(this, &poll_fd);
		mInitialized = true;
		return STATUS_OK;
	}

	// we are initialized, and told to process, so we must have a
	// socket waiting for a connection.
	lldebugs << "accepting socket" << llendl;

	PUMP_DEBUG;
	apr_pool_t* new_pool = NULL;
	apr_status_t status = apr_pool_create(&new_pool, mPool);
	if(ll_apr_warn_status(status))
	{
		if(new_pool)
		{	
			apr_pool_destroy(new_pool);
		}
		return STATUS_ERROR;
	}

	apr_socket_t* socket = NULL;
	status = apr_socket_accept(
		&socket,
		mListenSocket->getSocket(),
		new_pool);
	LLSocket::ptr_t llsocket(LLSocket::create(socket, new_pool));
	//EStatus rv = STATUS_ERROR;
	if(llsocket)
	{
		PUMP_DEBUG;

		apr_sockaddr_t* remote_addr;
		apr_socket_addr_get(&remote_addr, APR_REMOTE, socket);
		
		char* remote_host_string;
		apr_sockaddr_ip_get(&remote_host_string, remote_addr);

		LLSD context;
		context["remote-host"] = remote_host_string;
		context["remote-port"] = remote_addr->port;

		LLPumpIO::chain_t chain;
		chain.push_back(LLIOPipe::ptr_t(new LLIOSocketReader(llsocket)));
		if(mReactor->build(chain, context))
		{
			chain.push_back(LLIOPipe::ptr_t(new LLIOSocketWriter(llsocket)));
			pump->addChain(chain, mResponseTimeout);
			status = STATUS_OK;
		}
		else
		{
			llwarns << "Unable to build reactor to socket." << llendl;
		}
	}
	else
	{
		llwarns << "Unable to create linden socket." << llendl;
	}

	PUMP_DEBUG;
	// This needs to always return success, lest it get removed from
	// the pump.
	return STATUS_OK;
}


#if 0
LLIODataSocket::LLIODataSocket(
	U16 suggested_port,
	U16 start_discovery_port,
	apr_pool_t* pool) : 
	mSocket(NULL)
{
	if(!pool || (PORT_INVALID == suggested_port)) return;
	if(ll_apr_warn_status(apr_socket_create(&mSocket, APR_INET, SOCK_DGRAM, APR_PROTO_UDP, pool))) return;
	apr_sockaddr_t* sa = NULL;
	if(ll_apr_warn_status(apr_sockaddr_info_get(&sa, APR_ANYADDR, APR_UNSPEC, suggested_port, 0, pool))) return;
	apr_status_t status = apr_socket_bind(mSocket, sa);
	if((start_discovery_port > 0) && is_addr_in_use(status))
	{
		const U16 MAX_ATTEMPT_PORTS = 50;
		for(U16 attempt_port = start_discovery_port;
			attempt_port < (start_discovery_port + MAX_ATTEMPT_PORTS);
			++attempt_port)
		{
			sa->port = attempt_port;
			sa->sa.sin.sin_port = htons(attempt_port);
			status = apr_socket_bind(mSocket, sa);
			if(APR_SUCCESS == status) break;
			if(is_addr_in_use(status)) continue;
			(void)ll_apr_warn_status(status);
		}
	}
	if(ll_apr_warn_status(status)) return;
	if(sa->port)
	{
		lldebugs << "Bound datagram socket to port: " << sa->port << llendl;
		mPort = sa->port;
	}
	else
	{
		mPort = LLIOSocket::PORT_EPHEMERAL;
	}

	// set up the socket options options
	ll_apr_warn_status(apr_socket_timeout_set(mSocket, 0));
	ll_apr_warn_status(apr_socket_opt_set(mSocket, APR_SO_SNDBUF, LL_SEND_BUFFER_SIZE));
	ll_apr_warn_status(apr_socket_opt_set(mSocket, APR_SO_RCVBUF, LL_RECV_BUFFER_SIZE));
}

LLIODataSocket::~LLIODataSocket()
{
}


#endif