/*********************************************************************** * * ppp.c * * Implementation of user-space PPPoE redirector for Linux. * * Functions for talking to PPP daemon * * Copyright (C) 2000 by Roaring Penguin Software Inc. * * This program may be distributed according to the terms of the GNU * General Public License, version 2 or (at your option) any later version. * ***********************************************************************/ static char const RCSID[] = "$Id$"; #include "pppoe.h" #ifdef HAVE_SYSLOG_H #include #endif #include #include #include #ifdef HAVE_SYS_UIO_H #include #endif #ifdef HAVE_UNISTD_H #include #endif #ifdef HAVE_N_HDLC #ifndef N_HDLC #include #endif #endif int PPPState; int PPPPacketSize; unsigned char PPPXorValue; UINT16_t 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 }; /********************************************************************** *%FUNCTION: syncReadFromPPP *%ARGUMENTS: * conn -- PPPoEConnection structure * packet -- buffer in which to place PPPoE packet *%RETURNS: * Nothing *%DESCRIPTION: * Reads from a synchronous PPP device and builds and transmits a PPPoE * packet ***********************************************************************/ void syncReadFromPPP(PPPoEConnection *conn, PPPoEPacket *packet) { int r; #ifndef HAVE_N_HDLC struct iovec vec[2]; unsigned char dummy[2]; vec[0].iov_base = (void *) dummy; vec[0].iov_len = 2; vec[1].iov_base = (void *) packet->payload; vec[1].iov_len = ETH_DATA_LEN - PPPOE_OVERHEAD; /* Use scatter-read to throw away the PPP frame address bytes */ r = readv(0, vec, 2); #else /* Bloody hell... readv doesn't work with N_HDLC line discipline... GRR! */ unsigned char buf[ETH_DATA_LEN - PPPOE_OVERHEAD + 2]; r = read(0, buf, ETH_DATA_LEN - PPPOE_OVERHEAD + 2); if (r >= 2) { memcpy(packet->payload, buf+2, r-2); } #endif if (r < 0) { /* Catch the Linux "select" bug */ if (errno == EAGAIN) { rp_fatal("Linux select bug hit! This message is harmless, but please ask the Linux kernel developers to fix it."); } fatalSys("read (syncReadFromPPP)"); } if (r == 0) { syslog(LOG_INFO, "end-of-file in syncReadFromPPP"); sendPADT(conn, "RP-PPPoE: EOF in syncReadFromPPP"); exit(0); } if (r < 2) { rp_fatal("too few characters read from PPP (syncReadFromPPP)"); } sendSessionPacket(conn, packet, r-2); } /********************************************************************** *%FUNCTION: initPPP *%ARGUMENTS: * None *%RETURNS: * Nothing *%DESCRIPTION: * Initializes the PPP state machine ***********************************************************************/ void initPPP(void) { PPPState = STATE_WAITFOR_FRAME_ADDR; PPPPacketSize = 0; PPPXorValue = 0; } /********************************************************************** *%FUNCTION: asyncReadFromPPP *%ARGUMENTS: * conn -- PPPoEConnection structure * packet -- buffer in which to place PPPoE packet *%RETURNS: * Nothing *%DESCRIPTION: * Reads from an async PPP device and builds a PPPoE packet to transmit ***********************************************************************/ void asyncReadFromPPP(PPPoEConnection *conn, PPPoEPacket *packet) { unsigned char buf[READ_CHUNK]; unsigned char *ptr = buf; unsigned char c; int r; r = read(0, buf, READ_CHUNK); if (r < 0) { fatalSys("read (asyncReadFromPPP)"); } if (r == 0) { syslog(LOG_INFO, "end-of-file in asyncReadFromPPP"); sendPADT(conn, "RP-PPPoE: EOF in asyncReadFromPPP"); exit(0); } while(r) { if (PPPState == STATE_WAITFOR_FRAME_ADDR) { while(r) { --r; if (*ptr++ == FRAME_ADDR) { PPPState = STATE_DROP_PROTO; break; } } } /* Still waiting... */ if (PPPState == STATE_WAITFOR_FRAME_ADDR) return; while(r && PPPState == STATE_DROP_PROTO) { --r; if (*ptr++ == (FRAME_CTRL ^ FRAME_ENC)) { PPPState = STATE_BUILDING_PACKET; } } if (PPPState == STATE_DROP_PROTO) return; /* Start building frame */ while(r && PPPState == STATE_BUILDING_PACKET) { --r; c = *ptr++; switch(c) { case FRAME_ESC: PPPXorValue = FRAME_ENC; break; case FRAME_FLAG: if (PPPPacketSize < 2) { rp_fatal("Packet too short from PPP (asyncReadFromPPP)"); } sendSessionPacket(conn, packet, PPPPacketSize-2); PPPPacketSize = 0; PPPXorValue = 0; PPPState = STATE_WAITFOR_FRAME_ADDR; break; default: if (PPPPacketSize >= ETH_DATA_LEN - 4) { syslog(LOG_ERR, "Packet too big! Check MTU on PPP interface"); PPPPacketSize = 0; PPPXorValue = 0; PPPState = STATE_WAITFOR_FRAME_ADDR; } else { packet->payload[PPPPacketSize++] = c ^ PPPXorValue; PPPXorValue = 0; } } } } } /********************************************************************** *%FUNCTION: pppFCS16 *%ARGUMENTS: * fcs -- current fcs * cp -- a buffer's worth of data * len -- length of buffer "cp" *%RETURNS: * A new FCS *%DESCRIPTION: * Updates the PPP FCS. ***********************************************************************/ UINT16_t pppFCS16(UINT16_t fcs, unsigned char * cp, int len) { while (len--) fcs = (fcs >> 8) ^ fcstab[(fcs ^ *cp++) & 0xff]; return (fcs); }