/*

 File: NetworkHelper.c

 Abstract: Helper code for demonstration applications only

 Version: <1.0>

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 */

/*

 *  This is helper code that is not guaranteed to be complete or sufficient for a normal

 *  application.  This is purely for use in the example application.  It does not deal

 *  with network byte order.  Assumes packets are sent as is, with no interpretation.

 *

 */

#include "NetworkHelper.h"

#include <unistd.h>

#include <netinet/if_ether.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <netdb.h>

#include <stdio.h>

#include <stdlib.h>

#include <errno.h>

#include <string.h>

static int ReadData( int iSocket, char *outData, int inBytesToRead );

static int WriteData( int iSocket, char *inData, int inBytesToWrite );

int BindSocket( int inPort )

{

    struct sockaddr_in  stSocketAddr;

    int                 returnSocket;

    int                 iFlag           = 1;                 

    // create a socket for our use

    returnSocket = socket( AF_INET, SOCK_STREAM, 0 );

    if( returnSocket < 0) {

        printf( "Error:  Unable to create socket\n" );

        return -1;

    }

    // let's set it so the socket can be re-used right away for purposes of testing

    setsockopt( returnSocket, SOL_SOCKET, SO_REUSEADDR, (char *)&iFlag, sizeof(iFlag) );

    // set the socket address information

    stSocketAddr.sin_family = AF_INET;

    stSocketAddr.sin_port = htons( inPort );

    stSocketAddr.sin_addr.s_addr = INADDR_ANY;  

    // now bind to the socket

    if( bind(returnSocket, (struct sockaddr *) &stSocketAddr, sizeof(stSocketAddr)) < 0) {

        printf( "Error:  Unable to socket to port %d, must be in use\n", inPort );

        close( returnSocket ); // close out the socket

        return -1;

    }

    // now listen on the socket

    if( listen(returnSocket, 5) < 0 ) {

        printf( "Error:  Unable to listen on socket" );

        close( returnSocket ); // close out the socket

        return -1;

    } 

    return returnSocket;

}

int ConnectTo( char *inHostname, int inPort )

{

    struct sockaddr_in  stAddress;

    struct hostent      *pHostEntry;

    int                 iReturnSocket;

    pHostEntry = gethostbyname( inHostname );

    if( pHostEntry == NULL ) {

        printf( "Unknown host: %s\n", inHostname );

        return -1;

    }

    stAddress.sin_family = pHostEntry->h_addrtype;

    bcopy( pHostEntry->h_addr, (char *)&stAddress.sin_addr, sizeof(stAddress.sin_addr) );

    stAddress.sin_port = htons( inPort );

    iReturnSocket = socket( AF_INET, SOCK_STREAM, 0 );

    if( iReturnSocket > 0 ) {

        if( connect(iReturnSocket, (struct sockaddr *)&stAddress, sizeof(stAddress)) < 0) {

            close( iReturnSocket );

            iReturnSocket = -1;

        }

    } else {

        iReturnSocket = -1;

    }

    return iReturnSocket;

}

int ReadToken( int iSocket, char **outData )

{

    // first read the length of the data

    long    lLength     = 0;

    int     iBytesRead  = ReadData( iSocket, (char *) &lLength, sizeof(lLength) );

    // if we read a length, let's now get the data

    if( iBytesRead == sizeof(lLength) ) {

        // allocate memory based on the length we received, within reason

        if( lLength < 65536 ) {

            *outData = (char *) calloc( lLength, sizeof(char) );

            lLength = ReadData( iSocket, *outData, lLength );

        } else {

            lLength = -1;

        }

    } else {

        // network error?

        printf( "Error reading length byte from token, value was %d\n", iBytesRead );

        lLength = -1;

    }

    return lLength;

}

int SendToken( int iSocket, char *inData, long inBytesToWrite )

{

    // default to error state

    int iReturnValue = -1;

    // let's write out the length byte first..

    if( WriteData( iSocket, (char *)&inBytesToWrite, sizeof(inBytesToWrite) ) == sizeof(inBytesToWrite) ) {

        // if we succeeded, let's write out the data

        iReturnValue = WriteData( iSocket, inData, inBytesToWrite );

    }

    return iReturnValue;

}

#pragma mark -

#pragma mark Internal Support routines

int ReadData( int iSocket, char *outData, int inBytesToRead )

{

    fd_set          readFDS;

    int             iBytesRead      = 0;

    struct timeval  waitTime;

    waitTime.tv_sec = 30;

    waitTime.tv_usec = 0;

    while( inBytesToRead > 0 ) {

        FD_ZERO( &readFDS );

        FD_SET( iSocket, &readFDS );

        if( select(FD_SETSIZE, &readFDS, NULL, NULL, &waitTime ) <= 0 ||

            FD_ISSET(iSocket, &readFDS) == 0 ) {

            break;

        }

        int iBytes = recv( iSocket, &outData[iBytesRead], inBytesToRead, 0 );

        if( iBytes < 0 ) {

            // did we get interrupted, if so continue

            if( errno == EINTR )

                continue;

            // otherwise errored

            break;

        } else if (iBytes == 0) {

            break;

        }

        iBytesRead += iBytes;

        inBytesToRead -= iBytes;

    }

    return iBytesRead;

}

int WriteData( int iSocket, char *inData, int inBytesToWrite )

{

    int     iWroteBytes = 0;

    while( inBytesToWrite > 0 ) {

        int iWrote = send( iSocket, &inData[iWroteBytes], inBytesToWrite, 0 );

        if( iWrote < 0 ) {

            if( errno == EINTR )

                continue;

            break;

        } else if( iWrote == 0 ) {

            break;

        }

        inBytesToWrite -= iWrote;

        iWroteBytes += iWrote;

    }

    return iWroteBytes;

}