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- /*
- * fsm.c - {Link, IP} Control Protocol Finite State Machine.
- *
- * Copyright (c) 1989 Carnegie Mellon University.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms are permitted
- * provided that the above copyright notice and this paragraph are
- * duplicated in all such forms and that any documentation,
- * advertising materials, and other materials related to such
- * distribution and use acknowledge that the software was developed
- * by Carnegie Mellon University. The name of the
- * University may not be used to endorse or promote products derived
- * from this software without specific prior written permission.
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
- * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
- */
-
- /*
- * TODO:
- * Mechanism to exit() and/or drop DTR.
- * Hold-down on open?
- * Randomize fsm id on link/init.
- * Deal with variable outgoing MTU.
- */
-
- #include <stdio.h>
- #include <sys/types.h>
- #include <malloc.h>
- #include <syslog.h>
-
- #ifdef STREAMS
- #include <sys/stream.h>
- #include <sys/socket.h>
- #include <net/if.h>
- #endif
- #include "ppp.h"
- #include "fsm.h"
-
-
- static void fsm_timeout __ARGS((caddr_t));
- static void fsm_rconfack __ARGS((fsm *, u_char *, u_char, int));
- static void fsm_rconfnak __ARGS((fsm *, u_char *, u_char, int));
- static void fsm_rconfrej __ARGS((fsm *, u_char *, u_char, int));
- static void fsm_rtermreq __ARGS((fsm *, u_char));
- static void fsm_rtermack __ARGS((fsm *));
- static void fsm_rcoderej __ARGS((fsm *, u_char *, int));
- static void fsm_rprotrej __ARGS((fsm *, u_char *, int));
- static void fsm_sconfreq __ARGS((fsm *));
-
-
- /*
- * fsm_init - Initialize fsm.
- *
- * Initialize fsm state.
- */
- void
- fsm_init(f)
- fsm *f;
- {
- f->state = CLOSED;
- f->flags = 0;
- f->id = 0; /* XXX Start with random id? */
- }
-
-
- /*
- * fsm_activeopen - Actively open connection.
- *
- * Set new state, reset desired options and send requests.
- */
- void
- fsm_activeopen(f)
- fsm *f;
- {
- f->flags &= ~(AOPENDING|POPENDING); /* Clear pending flags */
- if (f->state == REQSENT || /* Already actively open(ing)? */
- f->state == ACKRCVD ||
- f->state == ACKSENT ||
- f->state == OPEN)
- return;
- if (f->state == TERMSENT || /* Closing or */
- !(f->flags & LOWERUP)) { /* lower layer down? */
- f->flags |= AOPENDING; /* Wait for desired event */
- return;
- }
- if (f->callbacks->resetci)
- (*f->callbacks->resetci)(f); /* Reset options */
- fsm_sconfreq(f); /* Send Configure-Request */
- TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
- f->state = REQSENT;
- f->retransmits = 0; /* Reset retransmits count */
- f->nakloops = 0; /* Reset nakloops count */
- }
-
-
- /*
- * fsm_passiveopen - Passively open connection.
- *
- * Set new state and reset desired options.
- */
- void
- fsm_passiveopen(f)
- fsm *f;
- {
- f->flags &= ~(AOPENDING|POPENDING); /* Clear pending flags */
- if (f->state == LISTEN || /* Already passively open(ing)? */
- f->state == OPEN)
- return;
- if (f->state == REQSENT || /* Active-Opening or */
- f->state == ACKRCVD ||
- f->state == ACKSENT ||
- f->state == TERMSENT || /* closing or */
- !(f->flags & LOWERUP)) { /* lower layer down? */
- f->flags |= POPENDING; /* Wait for desired event */
- return;
- }
- if (f->callbacks->resetci)
- (*f->callbacks->resetci)(f); /* Reset options */
- f->state = LISTEN;
- f->retransmits = 0; /* Reset retransmits count */
- f->nakloops = 0; /* Reset nakloops count */
- }
-
-
- /*
- * fsm_close - Start closing connection.
- *
- * Cancel timeouts and either initiate close or possibly go directly to
- * the CLOSED state.
- */
- void
- fsm_close(f)
- fsm *f;
- {
- f->flags &= ~(AOPENDING|POPENDING); /* Clear pending flags */
- if (f->state == CLOSED || /* Already CLOSED or Closing? */
- f->state == TERMSENT)
- return;
- if (f->state == REQSENT || /* Timeout pending for Open? */
- f->state == ACKRCVD ||
- f->state == ACKSENT)
- UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
- if (f->state == OPEN && /* Open? */
- f->callbacks->down)
- (*f->callbacks->down)(f); /* Inform upper layers we're down */
- if (f->state == ACKSENT || /* Could peer be OPEN? */
- f->state == OPEN) {
- fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0);
- /* Send Terminate-Request */
- TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
- f->state = TERMSENT;
- f->retransmits = 0; /* Reset retransmits count */
- }
- else {
- f->state = CLOSED;
- if (f->callbacks->closed)
- (*f->callbacks->closed)(f); /* Exit/restart/etc. */
- }
- }
-
-
- /*
- * fsm_timeout - Timeout expired.
- */
- static void
- fsm_timeout(arg)
- caddr_t arg;
- {
- fsm *f = (fsm *) arg;
- switch (f->state) {
- case REQSENT:
- case ACKRCVD:
- case ACKSENT:
- if (f->flags & POPENDING) { /* Go passive? */
- f->state = CLOSED; /* Pretend for a moment... */
- fsm_passiveopen(f);
- return;
- }
- if (f->callbacks->retransmit) /* If there is a retransmit rtn? */
- (*f->callbacks->retransmit)(f);
- fsm_sconfreq(f); /* Send Configure-Request */
- TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
- f->state = REQSENT;
- ++f->retransmits;
- f->nakloops = 0;
- break;
-
- case TERMSENT:
- if (f->flags & POPENDING) { /* Go passive? */
- f->state = CLOSED; /* Pretend for a moment... */
- fsm_passiveopen(f);
- return;
- }
- if (++f->retransmits > f->maxtermtransmits) {
- /*
- * We've waited for an ack long enough. Peer probably heard us.
- */
- f->state = CLOSED;
- if (f->callbacks->closed)
- (*f->callbacks->closed)(f); /* Exit/restart/etc. */
- return;
- }
- if (f->callbacks->retransmit) /* If there is a retransmit rtn? */
- (*f->callbacks->retransmit)(f);
- fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0);
- /* Send Terminate-Request */
- TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
- ++f->retransmits;
- }
- }
-
-
- /*
- * fsm_lowerup - The lower layer is up.
- *
- * Start Active or Passive Open if pending.
- */
- void
- fsm_lowerup(f)
- fsm *f;
- {
- f->flags |= LOWERUP;
- if (f->flags & AOPENDING) /* Attempting Active-Open? */
- fsm_activeopen(f); /* Try it now */
- else if (f->flags & POPENDING) /* Attempting Passive-Open? */
- fsm_passiveopen(f); /* Try it now */
- }
-
-
- /*
- * fsm_lowerdown - The lower layer is down.
- *
- * Cancel all timeouts and inform upper layers.
- */
- void
- fsm_lowerdown(f)
- fsm *f;
- {
- f->flags &= ~LOWERUP;
- if (f->state == REQSENT || /* Timeout pending? */
- f->state == ACKRCVD ||
- f->state == ACKSENT ||
- f->state == TERMSENT)
- UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
- if (f->state == OPEN && /* OPEN? */
- f->callbacks->down)
- (*f->callbacks->down)(f); /* Inform upper layers */
- f->state = CLOSED;
- if (f->callbacks->closed)
- (*f->callbacks->closed)(f); /* Exit/restart/etc. */
- }
-
-
- /*
- * fsm_protreject - Peer doesn't speak this protocol.
- *
- * Pretend that the lower layer went down.
- */
- void
- fsm_protreject(f)
- fsm *f;
- {
- fsm_lowerdown(f);
- }
-
-
- /*
- * fsm_input - Input packet.
- */
- void
- fsm_input(f, inpacket, l)
- fsm *f;
- u_char *inpacket;
- int l;
- {
- u_char *inp, *outp;
- u_char code, id;
- int len;
-
- /*
- * Parse header (code, id and length).
- * If packet too short, drop it.
- */
- inp = inpacket;
- if (l < HEADERLEN) {
- FSMDEBUG((LOG_WARNING, "fsm_input(%x): Rcvd short header.", f->protocol))
- return;
- }
- GETCHAR(code, inp);
- GETCHAR(id, inp);
- GETSHORT(len, inp);
- if (len < HEADERLEN) {
- FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd illegal length.",
- f->protocol))
- return;
- }
- if (len > l) {
- FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd short packet.",
- f->protocol))
- return;
- }
- len -= HEADERLEN; /* subtract header length */
-
- /*
- * Action depends on code.
- */
- switch (code) {
- case CONFREQ:
- FSMDEBUG((LOG_INFO, "fsm_rconfreq(%x): Rcvd id %d.",
- f->protocol, id))
-
- if (f->state == TERMSENT)
- return;
- if (f->state == CLOSED) {
- fsm_sdata(f, TERMACK, id, NULL, 0);
- return;
- }
- if (f->state == OPEN && f->callbacks->down)
- (*f->callbacks->down)(f); /* Inform upper layers */
- if (f->state == OPEN || f->state == LISTEN) {
- /* XXX Possibly need hold-down on OPEN? */
- fsm_sconfreq(f); /* Send Configure-Request */
- TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
- }
-
- if (f->callbacks->reqci) /* Check CI */
- code = (*f->callbacks->reqci)(f, inp, &len);
- else if (len)
- code = CONFREJ; /* Reject all CI */
-
- len += HEADERLEN; /* add header length back on */
-
- inp = inpacket; /* Reset to header */
- outp = outpacket_buf; /* get pointer to output buffer */
- MAKEHEADER(outp, f->protocol); /* paste in DLL header */
- BCOPY(inp, outp, len); /* copy input packet */
- PUTCHAR(code, outp); /* put in the code, id, and length*/
- PUTCHAR(id, outp);
- PUTSHORT(len, outp);
- output(f->unit, outpacket_buf, len + DLLHEADERLEN); /* send it out */
-
- if (code == CONFACK) {
- if (f->state == ACKRCVD) {
- UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
- if (f->callbacks->up)
- (*f->callbacks->up)(f); /* Inform upper layers */
- f->state = OPEN;
- }
- else
- f->state = ACKSENT;
- }
- else {
- if (f->state != ACKRCVD)
- f->state = REQSENT;
- }
- return;
-
- case CONFACK:
- fsm_rconfack(f, inp, id, len);
- break;
-
- case CONFNAK:
- fsm_rconfnak(f, inp, id, len);
- break;
-
- case CONFREJ:
- fsm_rconfrej(f, inp, id, len);
- break;
-
- case TERMREQ:
- fsm_rtermreq(f, id);
- break;
-
- case TERMACK:
- fsm_rtermack(f);
- break;
-
- case CODEREJ:
- fsm_rcoderej(f, inp, len);
- break;
-
- case PROTREJ:
- fsm_rprotrej(f, inp, len);
- break;
-
- case ECHOREQ:
- FSMDEBUG((LOG_INFO, "fsm_rechoreq(%x): Rcvd id %d.",
- f->protocol, id))
-
- switch (f->state) {
- case CLOSED:
- case LISTEN:
- fsm_sdata(f, TERMACK, id, NULL, 0);
- break;
-
- case OPEN:
- inp = inpacket; /* Reset to header */
- outp = outpacket_buf; /* get pointer to output buffer */
- MAKEHEADER(outp, f->protocol); /* add DLL header */
- len += HEADERLEN; /* add header length */
- BCOPY(inp, outp, len); /* copy input packet to output buffer */
- PUTCHAR(ECHOREP, outp); /* set code to echo reply */
- PUTCHAR(id, outp); /* add in id */
- PUTSHORT(len, outp); /* and length */
- output(f->unit, outpacket_buf, len + DLLHEADERLEN); /* send it */
- return;
- }
- break;
-
- case ECHOREP:
- case DISCREQ:
- /* XXX Deliver to ECHOREQ sender? */
- break;
-
- default:
- fsm_sdata(f, CODEREJ, ++f->id, inpacket, len + HEADERLEN);
- break;
- }
-
- }
-
-
- /*
- * fsm_rconfack - Receive Configure-Ack.
- */
- static void
- fsm_rconfack(f, inp, id, len)
- fsm *f;
- u_char *inp;
- u_char id;
- int len;
- {
- FSMDEBUG((LOG_INFO, "fsm_rconfack(%x): Rcvd id %d.",
- f->protocol, id))
-
- switch (f->state) {
- case LISTEN:
- case CLOSED:
- fsm_sdata(f, TERMACK, id, NULL, 0);
- break;
-
- case ACKRCVD:
- case REQSENT:
- if (id != f->reqid) /* Expected id? */
- break; /* Nope, toss... */
- if (f->callbacks->ackci &&
- (*f->callbacks->ackci)(f, inp, len)) /* Good ack? */
- f->state = ACKRCVD;
- else
- f->state = REQSENT; /* Wait for timeout to retransmit */
- break;
-
- case ACKSENT:
- if (id != f->reqid) /* Expected id? */
- break; /* Nope, toss... */
- if (f->callbacks->ackci &&
- (*f->callbacks->ackci)(f, inp, len)) { /* Good ack? */
- UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
- if (f->callbacks->up)
- (*f->callbacks->up)(f); /* Inform upper layers */
- f->state = OPEN;
- }
- else
- f->state = REQSENT; /* Wait for timeout to retransmit */
- break;
-
- case OPEN:
- if (f->callbacks->down)
- (*f->callbacks->down)(f); /* Inform upper layers */
- f->state = CLOSED; /* Only for a moment... */
- fsm_activeopen(f); /* Restart */
- break;
- }
- }
-
-
- /*
- * fsm_rconfnak - Receive Configure-Nak.
- */
- static void
- fsm_rconfnak(f, inp, id, len)
- fsm *f;
- u_char *inp;
- u_char id;
- int len;
- {
- FSMDEBUG((LOG_INFO, "fsm_rconfnak(%x): Rcvd id %d.",
- f->protocol, id))
-
- switch (f->state) {
- case LISTEN:
- case CLOSED:
- fsm_sdata(f, TERMACK, id, NULL, 0);
- break;
-
- case REQSENT:
- case ACKSENT:
- if (id != f->reqid) /* Expected id? */
- break; /* Nope, toss... */
- if (++f->nakloops > f->maxnakloops) {
- FSMDEBUG((LOG_INFO,
- "fsm_rconfnak(%x): Possible CONFNAK loop!",
- f->protocol))
- break; /* Break the loop */
- }
- UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
- if (f->callbacks->nakci)
- (*f->callbacks->nakci)(f, inp, len);
- fsm_sconfreq(f); /* Send Configure-Request */
- TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
- ++f->retransmits;
- break;
-
- case ACKRCVD:
- f->state = REQSENT; /* Wait for timeout to retransmit */
- break;
-
- case OPEN:
- if (f->callbacks->down)
- (*f->callbacks->down)(f); /* Inform upper layers */
- f->state = CLOSED; /* Only for a moment... */
- fsm_activeopen(f); /* Restart */
- break;
- }
- }
-
-
- /*
- * fsm_rconfrej - Receive Configure-Rej.
- */
- static void
- fsm_rconfrej(f, inp, id, len)
- fsm *f;
- u_char *inp;
- u_char id;
- int len;
- {
- FSMDEBUG((LOG_INFO, "fsm_rconfrej(%x): Rcvd id %d.",
- f->protocol, id))
-
- switch (f->state) {
- case LISTEN:
- case CLOSED:
- fsm_sdata(f, TERMACK, id, NULL, 0);
- break;
-
- case REQSENT:
- case ACKSENT:
- if (id != f->reqid) /* Expected id? */
- break; /* Nope, toss... */
- if (++f->nakloops > f->maxnakloops)
- break; /* Break the loop */
- UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
- if (f->callbacks->rejci)
- (*f->callbacks->rejci)(f, inp, len);
- fsm_sconfreq(f); /* Send Configure-Request */
- TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
- ++f->retransmits;
- break;
-
- case ACKRCVD:
- f->state = REQSENT; /* Wait for timeout to retransmit */
- break;
-
- case OPEN:
- f->state = CLOSED; /* Only for a moment... */
- fsm_activeopen(f); /* Restart */
- break;
- }
- }
-
-
- /*
- * fsm_rtermreq - Receive Terminate-Req.
- */
- static void
- fsm_rtermreq(f, id)
- fsm *f;
- u_char id;
- {
- FSMDEBUG((LOG_INFO, "fsm_rtermreq(%x): Rcvd id %d.",
- f->protocol, id))
-
- fsm_sdata(f, TERMACK, id, NULL, 0);
- switch (f->state) {
- case ACKRCVD:
- case ACKSENT:
- f->state = REQSENT; /* Start over but keep trying */
- break;
-
- case OPEN:
- if (f->callbacks->down)
- (*f->callbacks->down)(f); /* Inform upper layers */
- f->state = CLOSED;
- if (f->callbacks->closed)
- (*f->callbacks->closed)(f); /* Exit/restart/etc. */
- break;
- }
- }
-
-
- /*
- * fsm_rtermack - Receive Terminate-Ack.
- */
- static void
- fsm_rtermack(f)
- fsm *f;
- {
- FSMDEBUG((LOG_INFO, "fsm_rtermack(%x).", f->protocol))
-
- switch (f->state) {
- case OPEN:
- if (f->callbacks->down)
- (*f->callbacks->down)(f); /* Inform upper layers */
- f->state = CLOSED;
- if (f->callbacks->closed)
- (*f->callbacks->closed)(f); /* Exit/restart/etc. */
- break;
-
- case TERMSENT:
- UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
- f->state = CLOSED;
- if (f->callbacks->closed)
- (*f->callbacks->closed)(f); /* Exit/restart/etc. */
- break;
- }
- }
-
-
- /*
- * fsm_rcoderej - Receive an Code-Reject.
- */
- static void
- fsm_rcoderej(f, inp, len)
- fsm *f;
- u_char *inp;
- int len;
- {
- u_char code;
-
- FSMDEBUG((LOG_INFO, "fsm_rcoderej(%x).", f->protocol))
-
- if (len < sizeof (u_char)) {
- FSMDEBUG((LOG_INFO,
- "fsm_rcoderej: Rcvd short Code-Reject packet!"))
- return;
- }
- GETCHAR(code, inp);
- FSMDEBUG((LOG_INFO,
- "fsm_rcoderej: Rcvd Code-Reject for code %d!",
- code))
- }
-
-
- /*
- * fsm_rprotrej - Receive an Protocol-Reject.
- *
- * Figure out which protocol is rejected and inform it.
- */
- static void
- fsm_rprotrej(f, inp, len)
- fsm *f;
- u_char *inp;
- int len;
- {
- u_short prot;
-
- FSMDEBUG((LOG_INFO, "fsm_rprotrej."))
-
- if (len < sizeof (u_short)) {
- FSMDEBUG((LOG_INFO,
- "fsm_rprotrej: Rcvd short Protocol-Reject packet!"))
- return;
- }
- if (f->protocol != LCP) { /* Only valid for LCP */
- FSMDEBUG((LOG_INFO,
- "fsm_rprotrej: Rcvd non-LCP Protocol-Reject!"))
- return;
- }
-
- GETSHORT(prot, inp);
-
- FSMDEBUG((LOG_INFO,
- "fsm_rprotrej: Rcvd Protocol-Reject packet for %x!",
- prot))
- DEMUXPROTREJ(f->unit, prot); /* Inform protocol */
- }
-
-
- /*
- * fsm_sconfreq - Send a Configure-Request.
- */
- static void
- fsm_sconfreq(f)
- fsm *f;
- {
- u_char *outp;
- int outlen;
-
- outlen = HEADERLEN + (f->callbacks->cilen ? (*f->callbacks->cilen)(f) : 0);
- /* XXX Adjust outlen to MTU */
- outp = outpacket_buf;
- MAKEHEADER(outp, f->protocol);
-
- PUTCHAR(CONFREQ, outp);
- PUTCHAR(f->reqid = ++f->id, outp);
- PUTSHORT(outlen, outp);
- if (f->callbacks->cilen && f->callbacks->addci)
- (*f->callbacks->addci)(f, outp);
- output(f->unit, outpacket_buf, outlen + DLLHEADERLEN);
-
- FSMDEBUG((LOG_INFO, "fsm_sconfreq(%x): Sent id %d.",
- f->protocol, f->reqid))
- }
-
-
- /*
- * fsm_sdata - Send some data.
- *
- * Used for Terminate-Request, Terminate-Ack, Code-Reject, Protocol-Reject,
- * Echo-Request, and Discard-Request.
- */
- void
- fsm_sdata(f, code, id, data, datalen)
- fsm *f;
- u_char code, id;
- u_char *data;
- int datalen;
- {
- u_char *outp;
- int outlen;
-
- /* Adjust length to be smaller than MTU */
- if (datalen > MTU - HEADERLEN)
- datalen = MTU - HEADERLEN;
- outlen = datalen + HEADERLEN;
- outp = outpacket_buf;
- MAKEHEADER(outp, f->protocol);
- PUTCHAR(code, outp);
- PUTCHAR(id, outp);
- PUTSHORT(outlen, outp);
- if (datalen)
- BCOPY(data, outp, datalen);
- output(f->unit, outpacket_buf, outlen + DLLHEADERLEN);
-
- FSMDEBUG((LOG_INFO, "fsm_sdata(%x): Sent code %d, id %d.",
- f->protocol, code, id))
- }
-