/*///////////////////////////////////////////////////////////////////////////// File Name : PPP.C Author : Rene Trenado Location : Motorola Applications Lab, Baja California Date Created : September 2000 Current Revision : 0.0 Notes : This file contains the code for the PPP module /////////////////////////////////////////////////////////////////////////////*/ #include #include #include "CommDrv.h" #include "ppp.h" #include "IP.h" #include "Udp.h" #include "ICMP.h" const char * User = "MyName"; // Username of ISP account const char * Password = "MyPassword"; // Password of username /************************* Private Functions *************************/ static void HandleLCPOptions (void); static void HandleIPCPOptions (void); static WORD PPPfcs16 (WORD fcs, BYTE *cp, int len); static void RejectProtocol (BYTE *InBuffer); ////////////////////// Protected ROM Data ///////////////////////// static const BYTE PPPData [] = { 0xff,0x03,0xc0,0x21,0x02,0x01,0x00,0x04,0x00,0x00 }; static const BYTE LCPTerminate[] = { 0xff,0x03,0xc0,0x21,0x05,0x04,0x00,0x04,0x80,0xfe }; static const unsigned short fcstab[256] = { 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7, 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876, 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd, 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5, 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974, 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3, 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a, 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72, 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1, 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738, 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70, 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7, 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff, 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e, 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5, 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd, 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134, 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c, 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb, 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1, 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9, 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78 }; ///////////////////// Public R A M Data ///////////////////////////// volatile BYTE PPPStatus = 0; BYTE InBuffer [PPP_BUFFER_SIZE + 1]; /// Input Buffer for PPP data BYTE OutBuffer[PPP_BUFFER_SIZE + 1]; /// Output Buffer for PPP data ///////////////////// Protected R A M Data ///////////////////////// static BYTE *PPP_Packet = InBuffer; static volatile BYTE FrameSize = 0; static EventProc PPPEntryProc; /*********************************************************************** Function : PPPInit Parameters : None Date : September 2000 Desc : Initialize the PPP Module ***********************************************************************/ void PPPInit (void) { PPPStatus |= ReSync; } /*********************************************************************** Function : PPPGetInputBuffer Parameters : None Date : September 2000 Desc : Returns a PPP Input Buffer pointer to caller ***********************************************************************/ BYTE *PPPGetInputBuffer (void) { return &InBuffer[0]; } /*********************************************************************** Function : PPPGetOutputBuffer Parameters : None Date : September 2000 Desc : Returns a pointer to PPP Output Buffer to caller ***********************************************************************/ BYTE *PPPGetOutputBuffer (void) { return &OutBuffer[0]; } /*********************************************************************** Function : PPPfcs16 Parameters : fcs: current fcs cp: pointer to PPP data len: size of PPP data Date : September 2000 Desc : Calculate a new fcs given the current fcs and the new data. ***********************************************************************/ static WORD PPPfcs16 (WORD fcs, BYTE *cp, int len) { while (len--) fcs = (fcs >> 8) ^ fcstab[(fcs ^ *cp++) & 0xff]; return (fcs); } /*********************************************************************** Function : public PPPGetChecksum Parameters : cp: A pinter to the PPP Packet len: Size of PPP Packet Date : September 2000 Desc : Returns the Checksum of the PPP Packet pointed by cp ***********************************************************************/ WORD PPPGetChecksum (register unsigned char *cp, register int len) { return ~PPPfcs16( PPPINITFCS16, cp, len ); } /*********************************************************************** Function : ProcPPPReceive Parameters : A Byte character to stream in a PPP Packet Date : August 2000 Desc : This function process a BYTE following HDLC - PPP specifications. The Async event on input driver should call this function (usually the COMM ISR). ***********************************************************************/ void ProcPPPReceive (register BYTE c) { PPPStatus |= ByteRx; if (PPPStatus & IsFrame) return; if (PPPStatus & ReSync) { if (c != 0x7E) return; PPPStatus &= ~ReSync; FrameSize = 0; } if (PPPStatus & IsESC) { PPP_Packet [FrameSize++] = 0x20 ^ c; PPPStatus &= ~IsESC; } else { switch (c) { case ESC: //// Special ESC (0x7D) Character received PPPStatus |= IsESC; break; case END: //// Special END (0x7E) Character received if (FrameSize > 0) { //// Avoid cero length packets (0x7F - 0x7F conditions); PPP_Packet [FrameSize] = 0; PPPStatus |= IsFrame; //// Signal Frame availability } break; default: PPP_Packet [FrameSize++] = c; if (FrameSize > (PPP_BUFFER_SIZE - 6)) { FrameSize = 0; PPPStatus |= ReSync; } break; } } } /*********************************************************************** Function : PPPSend Parameters : Buffer: A pointer to a buffer containing the PPP packet to send len: the size of the PPP packet Date : September 2000 Desc : Sends a BYTE array of len length following HDLC - PPP specifications ***********************************************************************/ void ProcPPPSend (BYTE *Buffer, BYTE len) { WORD Checksum = 0; Checksum = PPPGetChecksum (Buffer, Buffer[7] + 4); Buffer [Buffer[7]+4] = Checksum & 0xFF; Buffer [Buffer[7]+5] = (Checksum >> 8) & 0xFF; WriteComm (0x7E); while (len--) { if ((signed char)*Buffer < (signed char)0x20) { WriteComm (0x7D); WriteComm (*Buffer ^ 0x20); } else { switch (*Buffer) { case 0x7E: WriteComm (0x7D); WriteComm (0x5E); break; case 0x7D: WriteComm (0x7D); WriteComm (0x5D); break; default: WriteComm (*Buffer); break; } } Buffer++; } WriteComm (0x7E); } /*********************************************************************** Function : public PPPFrameSize Parameters : None Date : August 2000 Desc : Returns the size of the current available PPP packet stored in InBuffer. Caller should call this function if needed only when the IsFram flag has been signaled. ***********************************************************************/ BYTE PPPFrameSize (void) { return FrameSize; } /*********************************************************************** Function : protected HandleLCPOptions Parameters : None Date : August 2000 Desc : State Machine that implements LCP packet negotiation ***********************************************************************/ static void HandleLCPOptions (void) { BYTE *dest = OutBuffer; // A pointer to the options of output buffer BYTE *ptr = (BYTE *)&InBuffer[8]; // A pointer to the options of input buffer switch (InBuffer [4] ) { //++++++++++++++++++++++++++++++++++++++++++++++++++++ case TERMINATE: //"Server Terminate-Request received" Move (InBuffer, OutBuffer, InBuffer[7]+6); OutBuffer [4] = TERMINATE_ACK; ProcPPPSend ((BYTE *)OutBuffer, OutBuffer[7] + 6); PPPStatus &= ~LinkOn; break; //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ case REQ: ////////////////////////////////////////////////////////////////////// /////// Server requesting option 2 /////// ////////////////////////////////////////////////////////////////////// if ((InBuffer [8] == 0x02) && (InBuffer [7] <= 0x0A)) { if ((InBuffer [10] == 0xFF) && (InBuffer [11] == 0xFF) && (InBuffer [12] == 0xFF) && (InBuffer [13] == 0xFF)) { InBuffer [4] = ACK; ProcPPPSend (InBuffer, InBuffer [7] + 6); return; } } else ////////////////////////////////////////////////////////////////////// /////// Server requesting first options, reject all but 3 /////// ////////////////////////////////////////////////////////////////////// if ((InBuffer [8] != 0x03) && (InBuffer [7] > 9)) { BYTE OptionsSize; BYTE Option; BYTE Size; Move (InBuffer, OutBuffer, 8); // Move LCP header to output buffer OutBuffer [4] = REJ; // Output will be a reject packet dest += 8; // Offset output pointer to LCP options OptionsSize = InBuffer[7] - 4; // Get size of LCP options in bytes while (OptionsSize > 0) { // Is there options to process? Option = *ptr; // Get option number Size = *(ptr + 1); // Get size of this option OptionsSize -= Size; // Reduce the amount of OptionsSize if (Option == 3) { // Is this option 3? (authentication protocol) ptr += Size; // Remove this option in output packet OutBuffer [7] = OutBuffer [7] - Size; // Set New Packet size } else { while (Size-- ) { // Copy this option to the output buffer *dest++ = *ptr++; } } } } 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 ProcPPPSend (InBuffer, InBuffer[7]+6); // Send the NAK reply 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, InBuffer[5] + 1, 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 field OutBuffer [3] = 0x21; OutBuffer [4] = REJ; // This will be 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; OutBuffer [7] = InBuffer [7] - Size; //Set New Packet 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 one to us 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 address IPAddress [1] = InBuffer [11]; IPAddress [2] = InBuffer [12]; IPAddress [3] = InBuffer [13]; PORTC = 0xFF; 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, BYTE ID, char* user, char* password) { OutBuffer [0] = 0xFF; OutBuffer [1] = 0x03; OutBuffer [2] = 0xC0; OutBuffer [3] = 0x23; OutBuffer [4] = Action; OutBuffer [5] = InBuffer [5] + 1; OutBuffer [6] = 0; OutBuffer [7] = strlen (user) + strlen (password) + 6; OutBuffer [8] = strlen (user); Move (user, &OutBuffer [9], strlen (user)); OutBuffer [9 + strlen (user)] = strlen (password); Move (password, &OutBuffer [10 + strlen (user)], strlen (password)); ProcPPPSend ((BYTE *)OutBuffer, OutBuffer[7] + 6); } /*********************************************************************** 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) { WORD Checksum; 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 NoOperation; } 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; }; PPPStatus &= ~IsFrame; PPPStatus |= ReSync; } }