/*
 *  PPP.C	-- Send and receive datagrams on serial lines with
 *		   Point-to-Point Protocol
 *
 *	This implementation of PPP is declared to be in the public domain.
 *
 *	Based (in part) upon previous implementations by:
 *	1989	-- Drew Daniel Perkins		(ddp@andrew.cmu.edu)
 *		   Carnegie Mellon University
 *	09-90	-- Katie Stevens		(dkstevens@ucdavis.edu)
 *		   UC Davis, Computing Services
 *
 *	Jan 91	Bill_Simpson@um.cc.umich.edu
 *		Computer Systems Consulting Services
 *
 *	Feb 91	Glenn McGregor			(ghm@merit.edu)
 *		Testing and suggestions.
 *
 *	May 91	Bill Simpson & Glenn McGregor
 *		Update to newest draft RFCs.
 *		Add support for echo and discard message sending.
 *		PAP prompt for password only when fails (allow missing password).
 */

#include <stdio.h>
#include <time.h>
#include "global.h"
#include "mbuf.h"
#include "timer.h"
#include "proc.h"
#include "iface.h"
#include "internet.h"
#include "ip.h"
#include "slhc.h"
#include "8250.h"
#include "asy.h"
#include "pktdrvr.h"
#include "socket.h"
#include "devparam.h"
#include "ppp.h"
#include "pppfsm.h"
#include "ppplcp.h"
#include "pppipcp.h"
#include "ppppap.h"
#include "trace.h"

/* Routines local to this file */
static struct mbuf *htonppp __ARGS((struct ppp_hdr *ppp, struct mbuf *data));

static void ppp_log __ARGS((struct ppp_s *ppp_p, char *comment));
static void ppp_in_error __ARGS((struct ppp_s *ppp_p, struct mbuf *bp, char *comment));
static void ppp_out_error __ARGS((struct ppp_s *ppp_p, struct mbuf *bp, char *comment));
static void ppp_unknown __ARGS((struct ppp_s *ppp_p, struct mbuf *bp, char *comment));

static int ppp_raw __ARGS((struct iface *iface, struct mbuf *data));

static void ppp_queue __ARGS((struct ppp_s *ppp_p, struct mbuf *bp, int16 negotiated));
static void ppp_recv __ARGS((int dev, void *p1, void *p2));
static int ppp_iostatus __ARGS((struct iface *ifp, int command, int32 value));
static void ppp_machine __ARGS((int dev, void *p1, void *p2));


/*
 * FCS lookup table as generated by fcsgen.c
 */
int16 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
};

#define pppfcs(fcs, c)		((fcs >> 8) ^ fcstab[(fcs ^ c) & 0x00ff])
#define SP_CHAR			0x20

/* actions for incoming bytes */
enum {
	modeTOSS,
	modeESCAPED,
	modeNORMAL
};

/****************************************************************************/

/* Convert PPP header in host form to network form */
static struct mbuf *
htonppp(ppp, data)
struct ppp_hdr *ppp;
struct mbuf *data;
{
	struct mbuf *bp;
	register char *cp;

	/* Prepend header onto packet data */
	if ((bp = pushdown(data, PPP_HDR_LEN)) == NULLBUF)
		return NULLBUF;

	/* Load header with proper values */
	cp = bp->data;
	*cp++ = ppp->addr;
	*cp++ = ppp->control;
	cp = put16(cp,ppp->protocol);

	return bp;
}

/* Extract PPP header from incoming packet */
int
ntohppp(ppp, bpp)
struct ppp_hdr *ppp;
struct mbuf **bpp;
{
	ppp->addr = PULLCHAR(bpp);
	ppp->control = PULLCHAR(bpp);
	ppp->protocol = pull16(bpp);
	return(PPP_HDR_LEN);
}


/************************************************************************/
/* General log routine */
static void
ppp_log( ppp_p, comment )
struct ppp_s *ppp_p;
char *comment;
{
	if (ppp_p->trace)
		log(-1,"%s: PPP %s",
			ppp_p->iface->name,
			comment);
}


/* Bad Input packet */
static void
ppp_in_error(ppp_p, bp, comment)
struct ppp_s *ppp_p;
struct mbuf *bp;
char *comment;
{
	ppp_p->InError++;
	free_p(bp);
	ppp_log( ppp_p, comment );
}


/* Bad output packet */
static void
ppp_out_error(ppp_p, bp, comment)
struct ppp_s *ppp_p;
struct mbuf *bp;
char *comment;
{
	ppp_p->OutError++;
	free_p(bp);
	ppp_log( ppp_p, comment );
}


/* Unknown type input packet */
static void
ppp_unknown(ppp_p, bp, comment)
struct ppp_s *ppp_p;
struct mbuf *bp;
char *comment;
{
	struct ipcp_s *ipcp_p;

	if ( (ipcp_p = ppp_p->fsm[IPcp].pdv) != NULL ) {
		slhc_toss( ipcp_p->slhcp );
	}
	ppp_in_error( ppp_p, bp, comment );
}


/****************************************************************************/
/* Send IP datagram with Point-to-Point Protocol */
int
ppp_send(bp,iface,gateway,prec,del,tput,rel)
struct mbuf *bp;	/* Buffer to send */
struct iface *iface;	/* Pointer to interface control block */
int32 gateway;		/* Ignored (PPP is point-to-point) */
int prec;
int del;
int tput;
int rel;
{
	struct ppp_s *ppp_p;
	struct ipcp_s *ipcp_p;
	int protocol = PPP_IP_PROTOCOL;

	if (iface == NULLIF
	 || (ppp_p = iface->extension) == NULL) {
		free_p(bp);
		return -1;
	}

	if (ppp_p->fsm[IPcp].state != fsmOPENED) {
		ppp_out_error( ppp_p, bp, "not open for IP traffic" );
		return -1;
	}

	ipcp_p = ppp_p->fsm[IPcp].pdv;
	if (ipcp_p->remote.work.negotiate & IPCP_N_COMPRESS) {
		/* Attempt IP/TCP header compression */
		switch ( slhc_compress(ipcp_p->slhcp, &bp,
			ipcp_p->remote.work.slot_compress) ) {
		case SL_TYPE_IP:
			protocol = PPP_IP_PROTOCOL;
			break;
		case SL_TYPE_COMPRESSED_TCP:
			protocol = PPP_COMPR_PROTOCOL;
			break;
		case SL_TYPE_UNCOMPRESSED_TCP:
			protocol = PPP_UNCOMP_PROTOCOL;
			break;
		default:
			ppp_out_error( ppp_p, bp, "bad IP packet" );
			return -1;
		};
	}
	ppp_p->OutIP++;
	return (*iface->output)(iface,NULLCHAR,NULLCHAR,protocol,bp);
}


/* Send a packet with PPP header */
int
ppp_output(iface,dest,source,protocol,data)
struct iface *iface;	/* Pointer to interface control block */
char *dest;		/* Dest addr (ignored; PPP is point-to-point) */
char *source;		/* Source addr (ignored; PPP is point-to-point) */
int16 protocol;		/* PPP Protocol Type field */
struct mbuf *data;	/* Actual data to be sent */
{
	struct ppp_s *ppp_p;
	struct mbuf *bp;
	struct ppp_hdr hdr;

	if (iface == NULLIF
	 || (ppp_p = iface->extension) == NULL) {
		free_p(data);
		return -1;
	}

	if (ppp_p->phase == pppDEAD) {
		ppp_out_error( ppp_p, data, "line not up" );
		return -1;
	}

	hdr.addr = HDLC_ALL_ADDR;
	hdr.control = HDLC_UI;
	hdr.protocol = protocol;

	if ((bp = htonppp(&hdr, data)) == NULLBUF) {
		ppp_out_error( ppp_p, data, Nospace );
		return -1;
	}

	return (*iface->raw)(iface,bp);
}


/* Encode a raw packet in PPP framing, put on link output queue */
static int
ppp_raw(iface,bp)
struct iface *iface;
struct mbuf *bp;
{
	struct ppp_s *ppp_p = iface->extension;
	struct lcp_s *lcp_p = ppp_p->fsm[Lcp].pdv;
	struct mbuf *hbp;
	struct ppp_hdr hdr;
	int full_lcp, full_ac, full_p;
	int16 calc_fcs = HDLC_FCS_START;
	int32 accm = LCP_ACCM_DEFAULT;
	int len = PPP_HDR_LEN;
	register char *cp;
	register int c;

	dump(iface,IF_TRACE_OUT,CL_PPP,bp);
	iface->rawsndcnt++;
	iface->lastsent = secclock();

	/* Get the HDLC/PPP header */
	ntohppp(&hdr, &bp);

	if ( ( full_lcp = (hdr.protocol == PPP_LCP_PROTOCOL) ) == 0
	 && (lcp_p->remote.work.negotiate & LCP_N_ACCM) ) {
		accm = lcp_p->remote.work.accm;
	}

	if ( ( full_p = ( full_lcp
			||  !(lcp_p->remote.work.negotiate & LCP_N_PFC)
			||  hdr.protocol > 0x00ff ) )
	    == 0 ) {
		--len;
	}

	/* Discard HDLC address and control fields if possible */
	if ( ( full_ac = ( full_lcp
			||  !(lcp_p->remote.work.negotiate & LCP_N_ACFC)
			||  ( !full_p
				&&  hdr.protocol == HDLC_ALL_ADDR
				&&  *bp->data == HDLC_UI ) ) )
	    == 0 ) {
		len -= 2;
	}

	/* Prepend header onto packet data */
	if ((hbp = pushdown(bp, len)) == NULLBUF) {
		ppp_out_error( ppp_p, bp, Nospace );
		return -1;
	}

	/* Load header with proper values */
	cp = hbp->data;
	if ( full_ac ) {
		*cp++ = hdr.addr;
		*cp++ = hdr.control;
	}
	if ( full_p )
		*cp++ = (hdr.protocol >> 8);
	*cp++ = (hdr.protocol & 0x00ff);

	/* Allocate output mbuf that's twice as long as the packet.
	 * This is a worst-case guess (consider a packet full of HDLC_FLAGs!)
	 */
	if ((bp = alloc_mbuf((int16)(2*len_p(hbp) + HDLC_ENVLEN))) == NULLBUF) {
		ppp_out_error( ppp_p, hbp, Nospace );
		return -1;
	}
	cp = bp->data;

	/* No need to send an opening flag if the previous packet is still
	 * being transmitted.
	 */
	if ( Asy[iface->dev].dma.flags == 0 ) {
		/* Flush out any line garbage */
		*cp++ = HDLC_FLAG;
		ppp_p->OutOpenFlag++;
	}

	/* Copy input to output, escaping special characters */
	while ((c = PULLCHAR(&hbp)) != -1) {
		/* Fold char value into FCS calculated so far */
		calc_fcs = pppfcs(calc_fcs, c);

		if ( ((c < SP_CHAR) && (accm & (1L << c)))
		    || (c == HDLC_ESC_ASYNC)
		    || (c == HDLC_FLAG)) {
			*cp++ = HDLC_ESC_ASYNC;
			*cp++ = (c ^ HDLC_ESC_COMPL);
		} else {
			*cp++ = c;
		}
	}

	/* Final FCS calculation */
	calc_fcs ^= 0xffff;
	c = (calc_fcs & 0x00ff);	/* Least significant byte first */
	if ( ((c < SP_CHAR) && (accm & (1L << c)))
	     ||(c == HDLC_ESC_ASYNC)
	     ||(c == HDLC_FLAG)) {
		*cp++ = HDLC_ESC_ASYNC;
		*cp++ = (c ^ HDLC_ESC_COMPL);
	} else {
		*cp++ = c;
	}
	c = (calc_fcs >> 8);		/* Most significant byte next */
	if ( ((c < SP_CHAR) && (accm & (1L << c)))
	     ||(c == HDLC_ESC_ASYNC)
	     ||(c == HDLC_FLAG)) {
		*cp++ = HDLC_ESC_ASYNC;
		*cp++ = (c ^ HDLC_ESC_COMPL);
	} else {
		*cp++ = c;
	}

	/* Tie off the packet */
	*cp++ = HDLC_FLAG;
	bp->cnt = cp - bp->data;

	if (iface->trace & IF_TRACE_RAW)
		raw_dump(iface,IF_TRACE_OUT,bp);
	ppp_p->OutTxPacketCount++;
	return asy_send(iface->dev,bp);
}


/****************************************************************************/
/* Queue packet for ppp_proc with full header */
/* (part of ppp_recv) */
static void
ppp_queue(ppp_p,bp,negotiated)
struct ppp_s *ppp_p;
struct mbuf *bp;
int16 negotiated;
{
	struct ppp_hdr hdr;
	struct mbuf *hbp;

	/* HDLC address and control fields may be compressed out */
	if ((byte_t)bp->data[0] != HDLC_ALL_ADDR) {
		if (!(negotiated & LCP_N_ACFC)) {
			ppp_unknown( ppp_p, bp, "missing ALL address" );
			return;
		}
	} else if ((byte_t)bp->data[1] != HDLC_UI) {
		if (!(negotiated & LCP_N_ACFC)
		 || !(negotiated & LCP_N_PFC)) {
			ppp_unknown( ppp_p, bp, "missing UI" );
			return;
		}
	} else {
		/* skip address/control fields */
		pull16(&bp);
	}

	/* Initialize the expected header */
	hdr.addr = HDLC_ALL_ADDR;
	hdr.control = HDLC_UI;
	hdr.protocol = PULLCHAR(&bp);

	/* First byte of PPP protocol field may be compressed out */
	if ( hdr.protocol & 0x01 ) {
		if (!(negotiated & LCP_N_PFC)) {
			ppp_unknown( ppp_p, bp, "missing upper protocol byte" );
			return;
		}
	} else {
		hdr.protocol = (hdr.protocol << 8) | PULLCHAR(&bp);

		/* Second byte of PPP protocol field must be odd */
		if ( !(hdr.protocol & 0x01) ) {
			ppp_unknown( ppp_p, bp, "missing lower protocol byte" );
			return;
		}
	}

	/* put full-size header on packet for dump routine */
	if ((hbp = htonppp(&hdr,bp)) == NULLBUF){
		ppp_unknown( ppp_p, bp, Nospace );
		return;
	}

	if ( net_route( ppp_p->iface, CL_PPP, hbp ) != 0 ) {
		ppp_unknown( ppp_p, hbp, Nospace );
	}
}


/* Packetize PPP input from device */
/* (process started by ppp_init) */
void
ppp_recv(dev,p1,p2)
int dev;
void *p1;
void *p2;
{
	struct iface *ifp = p1;
	struct ppp_s *ppp_p = ifp->extension;
	int16 negotiated = FALSE;
	int32 accm = LCP_ACCM_DEFAULT;
	int16 calc_fcs = HDLC_FCS_START;
	struct mbuf *raw_bp = NULLBUF;
	struct mbuf *head_bp = NULLBUF;
	register struct mbuf *tail_bp = NULLBUF;
	char *cp;			/* next byte in tail mbuf */
	register int mode = modeTOSS;
	register int c;

	while ( (c = get_asy(dev)) != -1 ) {
#ifdef PPP_DEBUG_RAW
		if (ifp->trace & IF_TRACE_RAW) {
			if ( raw_bp != NULLBUF
			  || (raw_bp = alloc_mbuf( LCP_MRU_HI * 2 )) != NULLBUF ) {
				*raw_bp->data++ = c;
				raw_bp->cnt++;
				if ( raw_bp->cnt != 1 && c == HDLC_FLAG ) {
					raw_bp->data = (char *)(raw_bp + 1);
					raw_dump( ifp, IF_TRACE_IN, raw_bp );
					raw_bp->cnt = 0;
				}
			}
		}
#endif
		if ( c == HDLC_FLAG ) {
			if (mode == modeESCAPED) {
				ppp_unknown( ppp_p, head_bp, "deliberate cancellation" );
			} else if ( head_bp != NULLBUF ) {
				if ( calc_fcs != HDLC_FCS_FINAL ) {
					ppp_unknown( ppp_p, head_bp, "checksum error" );
					ppp_p->InChecksum++;
				} else {
					ppp_queue(ppp_p, head_bp, negotiated);
				}
			} else {
				ppp_p->InOpenFlag++;
			}

			/* setup for next buffer */
			mode = modeNORMAL;
			head_bp = tail_bp = NULLBUF;
			calc_fcs = HDLC_FCS_START;
			accm = LCP_ACCM_DEFAULT;

			/* Use negotiated values if LCP finished */
			if (ppp_p->fsm[Lcp].state == fsmOPENED) {
				struct lcp_s *lcp_p = ppp_p->fsm[Lcp].pdv;

				negotiated = lcp_p->local.work.negotiate;
				if (negotiated & LCP_N_ACCM) {
					accm = lcp_p->local.work.accm;
				}
			}
#ifdef PPP_DEBUG_RAW
			if (!(ifp->trace & IF_TRACE_RAW)) {
				if ( raw_bp != NULLBUF ) {
					free_p( raw_bp );
					raw_bp = NULLBUF;
				}
			}
#endif
			continue;
		}

		/* We reach here for every byte inside a frame.
		 * (The order of the following tests is important.)
		 * Check for discard.
		 * Discard spurious control characters.
		 * Check for escape sequence.
		 * (Allow escaped escape.)
		 */
		if ( mode == modeTOSS ) {
			continue;
		} else if ( c < SP_CHAR && (accm & (1L << c)) ) {
			continue;
		} else if ( mode == modeESCAPED ) {
			mode = modeNORMAL;
			c ^= HDLC_ESC_COMPL;
		} else if ( c == HDLC_ESC_ASYNC ) {
			mode = modeESCAPED;
			continue;
		}

		/* We reach here with a byte for the buffer.
		 * Make sure there is room for it.
		 */
		if ( tail_bp == NULLBUF ) {
			if ((tail_bp = alloc_mbuf(PPP_ALLOC)) == NULLBUF) {
				ppp_unknown( ppp_p, tail_bp, Nospace );
				mode = modeTOSS;
				continue;
			}
			head_bp = tail_bp;
			cp = tail_bp->data;
		} else if ( tail_bp->cnt >= tail_bp->size ) {
			/* Current mbuf is full */
			if ( (tail_bp->next = alloc_mbuf(PPP_ALLOC)) == NULLBUF ) {
				/* No memory, drop the whole packet */
				ppp_unknown( ppp_p, head_bp, Nospace );
				head_bp = NULLBUF;
				mode = modeTOSS;
				continue;
			}
			tail_bp = tail_bp->next;
			cp = tail_bp->data;
		}

		/* Store the byte, increment counts */
		*cp++ = c;
		tail_bp->cnt++;
		calc_fcs = pppfcs(calc_fcs, c);
	}

	/* clean up afterward */
	free_p(raw_bp);
	free_p(head_bp);
	ifp->rxproc = NULLPROC;
}

/*#pragma option -G-*/
/* Process incoming PPP packets */
/* (called from network task) */
void
ppp_proc(iface,bp)
struct iface *iface;
struct mbuf *bp;
{
	struct ppp_s *ppp_p = iface->extension;
	struct ipcp_s *ipcp_p;
	struct ppp_hdr hdr;
	struct mbuf *hbp;

	if ( bp == NULLBUF )
		return;

	ppp_p->InRxPacketCount++;

	/* get PPP header */
	ntohppp(&hdr, &bp);

	/* trim off FCS bytes */
	trim_mbuf(&bp, len_p(bp)-2);

	switch(hdr.protocol) {
	case PPP_IP_PROTOCOL:	/* Regular IP */
		if ( ppp_p->fsm[IPcp].state != fsmOPENED ) {
			ppp_in_error( ppp_p, bp, "not open for IP traffic" );
			break;
		}
		ppp_p->InIP++;
		ip_route(iface,bp,0);
		break;

	case PPP_COMPR_PROTOCOL:	/* Van Jacobson Compressed TCP/IP */
		if ( ppp_p->fsm[IPcp].state != fsmOPENED ) {
			ppp_unknown( ppp_p, bp, "not open for Compressed TCP/IP traffic" );
			break;
		}

		ipcp_p = ppp_p->fsm[IPcp].pdv;
		if (!(ipcp_p->local.work.negotiate & IPCP_N_COMPRESS)) {
			ppp_unknown( ppp_p, bp, "Compressed TCP/IP not enabled" );
			break;
		}

		if ( slhc_uncompress(ipcp_p->slhcp, &bp) <= 0 ) {
			ppp_in_error( ppp_p, bp, "Compressed TCP/IP packet error" );
			break;
		}
		ppp_p->InIP++;
		ip_route(iface,bp,0);
		break;

	case PPP_UNCOMP_PROTOCOL:	/* Van Jacobson Uncompressed TCP/IP */
		if ( ppp_p->fsm[IPcp].state != fsmOPENED ) {
			ppp_unknown( ppp_p, bp, "not open for Uncompressed TCP/IP traffic" );
			break;
		}

		ipcp_p = ppp_p->fsm[IPcp].pdv;
		if (!(ipcp_p->local.work.negotiate & IPCP_N_COMPRESS)) {
			ppp_unknown( ppp_p, bp, "Uncompressed TCP/IP not enabled" );
			break;
		}

		if ( slhc_remember(ipcp_p->slhcp, &bp) <= 0 ) {
			ppp_in_error( ppp_p, bp, "Uncompressed TCP/IP packet error" );
			break;
		}
		ppp_p->InIP++;
		ip_route(iface,bp,0);
		break;

	case PPP_LCP_PROTOCOL:	/* Link Control Protocol */
		ppp_p->InNCP[Lcp]++;
		fsm_proc(&(ppp_p->fsm[Lcp]),bp);
		break;

	case PPP_PAP_PROTOCOL:	/* Password Authenticate Protocol */
		if (ppp_p->phase != pppAP) {
			ppp_in_error( ppp_p, bp, "not in Authentication phase;"
					" dropping PAP packet" );
			break;
		}
		ppp_p->InNCP[Pap]++;
		pap_proc(&(ppp_p->fsm[Pap]),bp);
		break;

	case PPP_IPCP_PROTOCOL:	/* IP Control Protocol */
		if (ppp_p->phase < pppREADY) {
			ppp_in_error( ppp_p, bp, "not ready for IPCP traffic" );
			break;
		}
		ppp_p->InNCP[IPcp]++;
		fsm_proc(&(ppp_p->fsm[IPcp]),bp);
		break;

	default:
		if ( ppp_p->trace )
			log( -1, "%s: PPP Unknown packet protocol: %x;",
				ppp_p->iface->name,
				hdr.protocol);
		ppp_p->InUnknown++;

		/* Build Protocol Reject packet:
		 * put the header back on ...
		 */
		if ((hbp = htonppp(&hdr,bp)) == NULLBUF){
			ppp_log( ppp_p, Nospace );
			free_p(bp);
			return;
		}
		/* ... then pull off the address and control fields ... */
		pull16(&hbp);
		/* ... and send it as an LCP packet */
		fsm_send( &(ppp_p->fsm[Lcp]), PROT_REJ, 0, hbp );
		break;
	};
}
/*#pragma option -G */

/****************************************************************************/

/* Keep track of changes in I-O status */
/* (called through iface iostatus vector) */
static int
ppp_iostatus( ifp, command, value )
struct iface *ifp;
int command;
int32 value;
{
	struct ppp_s *ppp_p = ifp->extension;

	switch ( command ) {
	case PARAM_UP:
		ppp_log( ppp_p, "Physical layer up" );

		ppp_p->phase = pppLCP;
		psignal(ppp_p, 0);
		return 0;
	case PARAM_DOWN:
		ppp_log( ppp_p, "Physical layer down" );

		fsm_down( &(ppp_p->fsm[Lcp]) );

		/* This point is a little tricky.
		 * If LCP was OPEN, it has just set the phase
		 * to TERMINATE.  But we don't want to terminate
		 * if a dialer is able to bring us up again.
		 * Otherwise, we got here because of TERMINATE.
		 * In either case, we change TERMINATE to DEAD.
		 */
		ppp_p->phase = pppDEAD;
		psignal(ppp_p, 0);
		return 0;
	};
	return -1;
}



/****************************************************************************/
/* PPP Overall Phase Machine
 *
 *	This machine is controlled by the pwait & psignal at ppp_p,
 *	whenever the overall link phase (as opposed to the LCP state) changes.
 */
void
ppp_machine(dev,p1,p2)
int dev;
void *p1;
void *p2;
{
	struct iface *ifp = p1;
	struct ppp_s *ppp_p = ifp->extension;
	struct lcp_s *lcp_p;

	for (;;) {
		switch ( ppp_p->phase ) {
		case pppDEAD:
			pwait(ppp_p);
			break;

		case pppLCP:		/* When Physical Line Up */
					/* or Open command */
			fsm_start( &(ppp_p->fsm[Lcp]) );
			pwait(ppp_p);
			break;

		case pppAP:		/* When LCP complete */
			lcp_p = ppp_p->fsm[Lcp].pdv;
			if (lcp_p->local.work.negotiate & LCP_N_AUTHENT) {
				ppp_p->flags |= PPP_AP_LOCAL;
				pap_local(ppp_p);
			}
			if (lcp_p->remote.work.negotiate & LCP_N_AUTHENT) {
				ppp_p->flags |= PPP_AP_REMOTE;
				if (pap_remote(ppp_p) != 0) {
					ppp_p->phase = pppTERMINATE;
					break;
				}
			}
			if (ppp_p->flags & (PPP_AP_LOCAL | PPP_AP_REMOTE)) {
				pwait(ppp_p);
				psignal( ppp_p->fsm[Pap].pdv, 0 );
			} else {
				ppp_p->phase = pppREADY;
				/* no waiting */
			}
			break;

		case pppREADY:		/* When no authentication */
					/* or AP authentication success */
			ppp_p->upsince = time(0L);
			fsm_start( &(ppp_p->fsm[IPcp]) );
			pwait(ppp_p);
			break;

		case pppTERMINATE:	/* When LCP terminating */
					/* or AP authentication failure */
			/* Tell the dialer to shut down */
			if ( ifp->supv != NULLPROC )
				alert( ifp->supv, EABORT );

			/* Close the link, if it isn't already */
			fsm_close( &(ppp_p->fsm[Lcp]) );
			ppp_p->phase = pppDEAD;
			break;
		};
	}
}


/****************************************************************************/
/* Initialize PPP control structures for a Point-to-Point interface */
int
ppp_init(ifp)
struct iface *ifp;
{
	struct ppp_s *ppp_p;
	char *ifn;

	if ((ppp_p = callocw(1,sizeof(struct ppp_s))) == NULL)
		return -1;

	ifp->extension = ppp_p;
	ifp->iostatus = ppp_iostatus;
	ifp->raw = ppp_raw;
	ifp->status = ppp_status;
	ifp->echo = ppp_echo;
	ifp->discard = ppp_discard;

	ppp_p->iface = ifp;
	ppp_p->phase = pppDEAD;

	ppp_p->machine = newproc( ifn = if_name( ifp, " machine" ),
			512, ppp_machine, ifp->dev, ifp, NULL, 0);
	free(ifn);
	pwait(NULL);	/* give machine a chance to run */

	ifp->rxproc = newproc( ifn = if_name( ifp, " receive" ),
			320, ppp_recv, ifp->dev, ifp, NULL, 0);
	free(ifn);
	return 0;
}


int
ppp_free(ifp)
struct iface *ifp;
{
	struct ppp_s *ppp_p = ifp->extension;
	int fsmi;

	alert( ifp->rxproc, -1 );
	killproc( ppp_p->machine );

	for ( fsmi = Lcp; fsmi < fsmi_Size; ) {
		fsm_free( &(ppp_p->fsm[fsmi++]) );
	}
	free( ppp_p );
	return 0;
}