ppp.c

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		} else
			//////////////////////////////////////////////////////////////////////
			/////// Server Request CHAP protocol, We reply with
			/////// a suggestion of the PAP protocol instead
			//////////////////////////////////////////////////////////////////////
			if ((InBuffer [8] == 0x03) && (InBuffer [10] == 0xC2)) {
				InBuffer [4] = NAK; // NAK CHAP protocol
				InBuffer [10] = 0xC0; // We suggest PAP instead
				// Send the NAK reply
				ProcPPPSend (InBuffer, InBuffer[7]+6);
				return;
			} else
				//////////////////////////////////////////////////////////////////////
				/////// Server Request PAP protocol //////////
				/////// We Acknowledge this reply and then we start negotiating
				/////// the Async-Control-Char..., Here we send both packets!!!
				//////////////////////////////////////////////////////////////////////
				if ((InBuffer [8] == 0x03) && (InBuffer [10] == 0xC0)) {
					Move (InBuffer, OutBuffer, InBuffer[7]+6);
					OutBuffer[4] = ACK;
					ProcPPPSend ((BYTE *)OutBuffer, OutBuffer[7] + 6);
					OutBuffer[4] = REQ;
					OutBuffer[5] = OutBuffer [5] + 1;
					OutBuffer[7] = 0x0A;
					OutBuffer[8] = 0x02;
					OutBuffer[9] = 0x06;
					OutBuffer[10] = 0xFF;
					OutBuffer[11] = 0xFF;
					OutBuffer[12] = 0xFF;
					OutBuffer[13] = 0xFF;
				}
				ProcPPPSend ((BYTE *)OutBuffer, OutBuffer[7] + 6);
				break;
				//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
case ACK:
	//////////////////////////////////////////////////////////////////////
	/////// Server Acknowledge Async Control //////////
	//////////////////////////////////////////////////////////////////////
	if (InBuffer [8] == 0x02) {
		SendPAPPacket (REQ, User, Password);
	}
	break;
	//++++++++++++++++++++++++++++++++++++++++++++++++++++
case NAK:
	break;
	//++++++++++++++++++++++++++++++++++++++++++++++++++++
case REJ:
	break;
	//++++++++++++++++++++++++++++++++++++++++++++++++++++
case TERMINATE_ACK: // Terminate ACK!
	PPPStatus &= ~LinkOn;
	break;
	}
	return;
}
/***********************************************************************
Function : protected HandleIPCPOptions
Parameters : None
Date : August 2000
Desc : State Machine that implement IPCP packet negotiation
***********************************************************************/
static void HandleIPCPOptions (void) {
	BYTE *dest = (BYTE *)&OutBuffer[8];
	BYTE *ptr = (BYTE *)&InBuffer[8];
	BYTE FrameSize;
	BYTE Option;
	BYTE Size;
	switch (InBuffer [4] ) {
case REQ:
	if ((InBuffer [8] != 0x03) && (InBuffer [7] > 0x0A)) {
		OutBuffer [0] = 0xFF; // Build a IPCP header
		OutBuffer [1] = 0x03;
		OutBuffer [2] = 0x80; // Set IPCP protocol
		OutBuffer [3] = 0x21;
		OutBuffer [4] = REJ; // This will be a
		// REJ packet for now
		OutBuffer [5] = InBuffer [5];
		FrameSize = InBuffer[7] - 4;
		///////// Ignore all but option #3 ///////
		while (FrameSize > 0) {
			Option = *ptr;
			Size = *(ptr + 1);
			FrameSize -= Size;
			if (Option == 3) {
				ptr += Size;
				//Set New Packet size
				OutBuffer [7] = InBuffer [7] - Size;
			}
			else {
				while (Size-- ) {
					*dest++ = *ptr++;
				}
			}
		}
	}
	else {
		// Acknowledge IP Address //
		Move (InBuffer, OutBuffer, InBuffer[7]+6);
		OutBuffer [4] = ACK;
		ProcPPPSend ((BYTE *)OutBuffer, OutBuffer[7] + 6);
		// Now Request IP address to complete 3-way handshake
		OutBuffer [4] = REQ; // Request command
		OutBuffer [5] = OutBuffer [5] + 1; // Packet ID = ID + 1
		OutBuffer [10] = 0; // IP address is set
		// to 0 so ISP server
		OutBuffer [11] = 0; // can assing us one
		OutBuffer [12] = 0;
		OutBuffer [13] = 0;
	}
	ProcPPPSend ((BYTE *)OutBuffer, OutBuffer[7] + 6);
	break;
case ACK:
	if (InBuffer [8] == 3) { // Reply of the only IPCP
		// Request we can send
		IPAddress [0] = InBuffer [10]; // ISP assigned IP
		IPAddress [1] = InBuffer [11];
		IPAddress [2] = InBuffer [12];
		IPAddress [3] = InBuffer [13];
		
		PPPStatus |= LinkOn; // PPP Link is now up
	}
	break;
case NAK:
	if ((InBuffer[8] == 0x03) && (InBuffer [7] <= 0x0A)) {
		/// Request IP Address ////
		Move (InBuffer, OutBuffer, InBuffer[7]+6);
		OutBuffer[4] = 0x01;
		ProcPPPSend ((BYTE *)OutBuffer, OutBuffer[7] + 6);
	}
	break;
case REJ:
	break;
	}
}
/***********************************************************************
Function : public PPPSendPAPPacket
Parameters : Action: REQ, REJ, NAK
ID: Sequence number of PPP packet
user: User name for login
password: Password in plain text
Date : September 2000
Desc : Formats a PAP packet on Output Buffer. This function
supports the type field for future implementation of
the PPP module in server mode.
***********************************************************************/
void SendPAPPacket (BYTE Action,char* user, char* password) {
	OutBuffer[0] = 0xFF;
	OutBuffer[1] = 0x03;
	OutBuffer[2] = 0xC0; // Format PAP packet header
	OutBuffer[3] = 0x23;
	OutBuffer[4] = Action;
	OutBuffer[5] = InBuffer[5] + 1; // Increment ID
	OutBuffer[6] = 0;
	OutBuffer[7] = strlen (user) + strlen (password) + 6;// Set length of PAP
	OutBuffer[8] = strlen (user); // Set length of
	// Username
	Move (user, &OutBuffer [9], strlen (user)); // Store Username
	OutBuffer [9 + strlen (user)] = strlen (password); // Set length of
	// password
	Move (password, &OutBuffer [10 + strlen (user)], strlen (password));
	ProcPPPSend ((BYTE *)OutBuffer, OutBuffer[7] + 6); // Send PAP packet
}
/***********************************************************************
Function : Move
Parameters : src: A pointer to the data to copy
dest: A pointer to the destination location
numBYTEs: Number of bytes to copy
Date : September 2000
Desc : Copies a block of numBYTEs bytes from src pointer
to dest pointer
***********************************************************************/
void Move (BYTE *src, BYTE *dest, register numBYTEs) {
	if ( numBYTEs <= 0 ) return;
	if ( src < dest ) {
		src += numBYTEs;
		dest += numBYTEs;
		do {
			*--dest = *--src;
		} while ( --numBYTEs > 0 );
	} else
		do {
			*dest++ = *src++;
		} while ( --numBYTEs > 0 );
}
/***********************************************************************
Function : protected RejectProtocol
Parameters : InBuffer -> A pointer to the buffer that has the PPP
Packet to reject
Date : August 2000
Desc : Rejects the a PPP packet based on its Protocol field
Stored on InBuffer
***********************************************************************/
static void RejectProtocol (BYTE *InBuffer) {
	OutBuffer[0] = 0xFF;
	OutBuffer[1] = 0x03;
	OutBuffer[2] = 0xC0;
	OutBuffer[3] = 0x21;
	OutBuffer[4] = 0x08;
	OutBuffer[5] = 20;
	OutBuffer[6] = 0;
	OutBuffer[7] = InBuffer[7] + 6;
	Move (&InBuffer[2], &OutBuffer[8], InBuffer [7] + 2);
	ProcPPPSend ((BYTE *)OutBuffer, OutBuffer[7] + 6);
}
/***********************************************************************
Function : protected PPPSendVoidLcp
Parameters : None
Date : September 2000
Desc : Sends a void LCP packet with no options to the PPP Server.
This will force the server to reply with his options to
negotiate. Some ISPs require scripts to stablish a connection thus
a void LCP packet will try to force the server to negotiate PPP.
***********************************************************************/
void PPPSendVoidLCP (void) {
	
	Move (PPPData, OutBuffer, PPPData[7] + 6);
	ProcPPPSend ((BYTE *)OutBuffer, OutBuffer[7] + 6);
}
/***********************************************************************
Function : PPPTerminate
Parameters : None
Date : September 2000
Desc : Terminates a PPP link by sending a terminate LCP packet
***********************************************************************/
void PPPTerminate (void) {
	Move ((BYTE *)LCPTerminate, OutBuffer, 10);
	ProcPPPSend (OutBuffer, 10);
}
/***********************************************************************
Function : PPPEntry
Parameters : None
Date : August 2000
Desc : PPP Module Entry, Applications should call PPPEntry
frequently in the main loop or in portions of the app
code.
***********************************************************************/
void PPPEntry (void) {
	if (PPPStatus & IsFrame) {
		switch (*(WORD *)(&InBuffer[2])) {
case LCP_PACKET:
	HandleLCPOptions ();
	break;
case PAP_PACKET:
	if (InBuffer[4] == 0x02) {// Authentication OK
		}
	break;
case IPCP_PACKET: // IPCP Handler
	HandleIPCPOptions ();
	break;
case IP_DATAGRAM: // IP Data Handler
	if (!IPCompare ((BYTE *)&InBuffer[20])) {
		// Misrouted datagram or broadcast
		// message received
	}
	else
		switch (InBuffer[13]) {
case UDP:
	UDP_Handler ((UDPDatagram *)&InBuffer[16]);
	break;
case TCP:
	break;
case ICMP:
	IcmpHandler ((IPDatagram *)&InBuffer[4]);
	break;
default:
	break;
		}
		break;
default:
	RejectProtocol (InBuffer);// Cannot handle this type of packet
	break;
		} // End of switch statement
		PPPStatus &= ~IsFrame;
		PPPStatus |= ReSync;
	} // End of if IsFrame
}