/ClassMaster2014/barahon/Cultivation_9_UnixSource/minorGems/network/linux/SocketLinux.cpp

/*
 * Modification History
 *
 * 2001-January-9		Jason Rohrer
 * Created.
 *
 * 2001-January-10		Jason Rohrer
 * Fixed a bug in the receive code (in use of timed_read).
 *
 * 2001-January-15		Jason Rohrer
 * Added a safeguard against receives that exceed the 
 * network buffer size.
 *
 * 2001-January-28		Jason Rohrer
 * Changed to comply with new initSocketFramework Socket interface. 
 * Added a close() call to the destructor.  
 *
 * 2001-January-29		Jason Rohrer
 * Fixed compile bug by including unistd.h for close call.
 *
 * 2001-November-13		Jason Rohrer
 * Changed to use ::send function instead of __send function.
 * Changed timeout parameter to signed, since -1 is a possible argument. 
 *
 * 2001-December-12		Jason Rohrer
 * Changed the include order to make BSD compatible.
 *
 * 2002-August-2   Jason Rohrer
 * Changed to ignore SIGPIPE.
 * Added functon for getting remote host address.
 * Added fix for linux-BSD differences.
 *
 * 2002-November-15   Jason Rohrer
 * Fixed a security hole when getting the remote host address.
 *
 * 2003-February-3   Jason Rohrer
 * Added a function for getting the local host address from a socket.
 *
 * 2003-February-21   Jason Rohrer
 * Fixed a BSD compatibility bug.
 *
 * 2004-January-4   Jason Rohrer
 * Added use of network function locks.
 *
 * 2004-March-23   Jason Rohrer
 * Removed timeout error message.
 *
 * 2004-December13   Jason Rohrer
 * Added a breakConnection function.
 *
 * 2005-July-5   Jason Rohrer
 * Added port number when getting address of remote host.
 *
 * 2006-May-28   Jason Rohrer
 * Changed timeout behavior slightly to support emulation of non-blocking mode.
 * Added support for non-blocking sends.
 *
 * 2006-June-5   Jason Rohrer
 * Fixed error checking for non-blocking sends.
 *
 * 2006-June-23   Jason Rohrer
 * Changed implementation of non-blocking sends to work on Mac.
 *
 * 2008-September-30   Jason Rohrer
 * Added support for non-blocking connect.
 * Fixed close-detection in non-blocking read.
 *
 * 2009-April-3   Jason Rohrer
 * OpenBSD support.
 *
 * 2010-January-26  Jason Rohrer
 * Fixed socklen_t on later versions of MacOSX.
 *
 * 2010-January-26  Jason Rohrer
 * Added support for disabling Nagle algorithm.
 */



#include "minorGems/network/Socket.h"
#include "minorGems/network/NetworkFunctionLocks.h"

#include <sys/time.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <netdb.h>

#include <stdio.h>
#include <fcntl.h>
#include <time.h>
#include <string.h>

#include <unistd.h>
#include <signal.h>
#include <errno.h>



// BSD does not define socklen_t
#ifdef BSD
#ifndef IPHONE
#ifndef __OpenBSD__
#ifndef _SOCKLEN_T     // later versions of MacOS define it and mark it
typedef int socklen_t;
#endif
#endif
#endif
#endif



// prototypes
int timed_read( int inSock, unsigned char *inBuf, 
	int inLen, long inMilliseconds );



/**
 * Linux-specific implementation of the Socket class member functions.
 *
 * May also be compatible with other POSIX-like systems.
 *
 * To compile:
 * no special options needed
 */



char Socket::sInitialized = false;



int Socket::initSocketFramework() {
    // ignore SIGPIPE, which occurs on send whenever the receiver
    // has closed the socket
    signal(SIGPIPE, SIG_IGN);

    sInitialized = true;
	return 0;
	}



Socket::~Socket() {
	int *socketIDptr = (int *)( mNativeObjectPointer );
	int socketID = socketIDptr[0];

    if( !mIsConnectionBroken ) {

        shutdown( socketID, SHUT_RDWR );
        mIsConnectionBroken = true;
        }
    
	close( socketID );
	
	delete [] socketIDptr;
	}



int Socket::isConnected() {
    
    if( mConnected ) {
        return 1;
        }
    
    int *socketIDptr = (int *)( mNativeObjectPointer );
	int socketID = socketIDptr[0];

    int ret;
	fd_set fsr;
	struct timeval tv;
	int val;
    socklen_t len;

	FD_ZERO( &fsr );
	FD_SET( socketID, &fsr );

    // check if connection event waiting right now
    // timeout of 0
    tv.tv_sec = 0;
	tv.tv_usec = 0;    

	ret = select( socketID + 1, NULL, &fsr, NULL, &tv );

	if( ret==0 ) {
		// timeout
		return 0;
        }

    // no timeout
    // error?

	len = 4;
	ret = getsockopt( socketID, SOL_SOCKET, SO_ERROR, &val, &len );
	
	if( ret < 0 ) {
		// error
        return -1;
        }

	if( val != 0 ) {
        // error
		return -1;
        }
	
    // success
    mConnected = true;
    
    return 1;
    }



void Socket::setNoDelay( int inValue ) {
	int *socketIDptr = (int *)( mNativeObjectPointer );
	int socketID = socketIDptr[0];

    int flag = inValue;
    setsockopt( socketID,
                IPPROTO_TCP,
                TCP_NODELAY,
                (char *) &flag,
                sizeof(int) ); 
    }



int Socket::send( unsigned char *inBuffer, int inNumBytes,
                  char inAllowedToBlock,
                  char inAllowDelay ) {
	
	int *socketIDptr = (int *)( mNativeObjectPointer );
	int socketID = socketIDptr[0];

    

    if( inAllowedToBlock ) {
        if( ! inAllowDelay ) {
            // turn nodelay on
            setNoDelay( 1 );
            }
            
        int returnVal = ::send( socketID, inBuffer, inNumBytes, 0 );
        
        if( ! inAllowDelay ) {
            // turn nodelay back off
            setNoDelay( 0 );
            }

        return returnVal;
        }
    else {

        // set to non-blocking mode
        int result = fcntl( socketID, F_SETFL, O_NONBLOCK );

        if( result < 0 ) {
            return result;
            }
        
        if( ! inAllowDelay ) {
            // turn nodelay on
            setNoDelay( 1 );
            }


        int returnValue = ::send( socketID, inBuffer, inNumBytes,
                                  // no flags
                                  0 );
        
        
        if( ! inAllowDelay ) {
            // turn nodelay back off
            setNoDelay( 0 );
            }


        // back into blocking mode
        result = fcntl( socketID, F_SETFL, 0 );

        if( result < 0 ) {
            return result;
            }

        
        if( returnValue == -1 && errno == EAGAIN ) {
            return -2;
            }
        else {
            return returnValue;
            }
        }
    }
		
		
int Socket::receive( unsigned char *inBuffer, int inNumBytes,
	long inTimeout ) {
	
	int *socketIDptr = (int *)( mNativeObjectPointer );
	int socketID = socketIDptr[0];
	
	if( inTimeout == -1 ) {
        // use MSG_WAITALL flag here to block until inNumBytes has arrived
		return recv( socketID, inBuffer, inNumBytes, MSG_WAITALL );
		}
	else {		
		return timed_read( socketID, inBuffer, inNumBytes, inTimeout );
		}
	}



void Socket::breakConnection() {
	int *socketIDptr = (int *)( mNativeObjectPointer );
	int socketID = socketIDptr[0];

    if( !mIsConnectionBroken ) {

        shutdown( socketID, SHUT_RDWR );
        mIsConnectionBroken = true;
        }
    
	close( socketID );
    }



HostAddress *Socket::getRemoteHostAddress() {
    int *socketIDptr = (int *)( mNativeObjectPointer );
	int socketID = socketIDptr[0];

    // adapted from Unix Socket FAQ
    
    socklen_t len;
    struct sockaddr_in sin;
    
    len = sizeof sin;
    int error = getpeername( socketID, (struct sockaddr *) &sin, &len );

    if( error ) {
        return NULL;
        }

    // this is potentially insecure, since a fake DNS name might be returned
    // we should use the IP address only
    //
    // struct hostent *host = gethostbyaddr( (char *) &sin.sin_addr,
    //                                       sizeof sin.sin_addr,
    //                                       AF_INET );


    NetworkFunctionLocks::mInet_ntoaLock.lock();
    // returned string is statically allocated, copy it
    char *ipAddress = stringDuplicate( inet_ntoa( sin.sin_addr ) );
    NetworkFunctionLocks::mInet_ntoaLock.unlock();

    int port = ntohs( sin.sin_port );
    
    return new HostAddress( ipAddress, port );    
    }



HostAddress *Socket::getLocalHostAddress() {
    int *socketIDptr = (int *)( mNativeObjectPointer );
	int socketID = socketIDptr[0];

    // adapted from GTK-gnutalla code, and elsewhere

    struct sockaddr_in addr;
	socklen_t len = sizeof( struct sockaddr_in );

    int result = getsockname( socketID, (struct sockaddr*)( &addr ), &len );

    if( result == -1 ) {
        return NULL;
        }
    else {

        char *stringAddress = inet_ntoa( addr.sin_addr );

        return new HostAddress( stringDuplicate( stringAddress ),
                                0 );
        }
    
    }



/* timed_read adapted from gnut, by Josh Pieper */
/* Josh Pieper, (c) 2000 */
/* This file is distributed under the GPL, see file COPYING for details */

// exactly like the real read, except that it returns -2
// if no data was read before the timeout occurred...
int timed_read( int inSock, unsigned char *inBuf, 
	int inLen, long inMilliseconds ) {
	fd_set fsr;
	struct timeval tv;
	int ret;
	
	//ret = fcntl( inSock, F_SETFL, O_NONBLOCK );
	
	FD_ZERO( &fsr );
	FD_SET( inSock, &fsr );
 
	tv.tv_sec = inMilliseconds / 1000;
	int remainder = inMilliseconds % 1000;
	tv.tv_usec = remainder * 1000;
	
	ret = select( inSock + 1, &fsr, NULL, NULL, &tv );
	
	if( ret==0 ) {
		// printf( "Timed out waiting for data on socket receive.\n" );
		return -2;
		}
	
	if( ret<0 ) {
		printf( "Selecting socket during receive failed.\n" );
		return ret;
		}

    // do not use MSG_WAITALL flag here, since we just want to return
    // data that is available
	ret = recv( inSock, inBuf, inLen, 0 );
	

    if( ret == 0  ) {
        // select came back as 1, but no data there
        // connection closed on remote end
        return -1;
        }
    
	//fcntl( inSock, F_SETFL, 0 );
	
	return ret;
	}