diff options
Diffstat (limited to 'usr.sbin/pppd/fsm.c')
| -rw-r--r-- | usr.sbin/pppd/fsm.c | 773 |
1 files changed, 773 insertions, 0 deletions
diff --git a/usr.sbin/pppd/fsm.c b/usr.sbin/pppd/fsm.c new file mode 100644 index 0000000..902ad64 --- /dev/null +++ b/usr.sbin/pppd/fsm.c @@ -0,0 +1,773 @@ +/* + * 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. + */ + +#ifndef lint +static char rcsid[] = "$Id: fsm.c,v 1.3 1994/05/24 11:21:10 paulus Exp $"; +#endif + +/* + * TODO: + * Randomize fsm id on link/init. + * Deal with variable outgoing MTU. + */ + +#include <stdio.h> +#include <sys/types.h> +#include <syslog.h> + +#include "ppp.h" +#include "pppd.h" +#include "fsm.h" + +extern char *proto_name(); + +static void fsm_timeout __ARGS((caddr_t)); +static void fsm_rconfreq __ARGS((fsm *, int, u_char *, int)); +static void fsm_rconfack __ARGS((fsm *, int, u_char *, int)); +static void fsm_rconfnakrej __ARGS((fsm *, int, int, u_char *, int)); +static void fsm_rtermreq __ARGS((fsm *, int)); +static void fsm_rtermack __ARGS((fsm *)); +static void fsm_rcoderej __ARGS((fsm *, u_char *, int)); +static void fsm_sconfreq __ARGS((fsm *, int)); + +#define PROTO_NAME(f) ((f)->callbacks->proto_name) + +int peer_mru[NPPP]; + + +/* + * fsm_init - Initialize fsm. + * + * Initialize fsm state. + */ +void +fsm_init(f) + fsm *f; +{ + f->state = INITIAL; + f->flags = 0; + f->id = 0; /* XXX Start with random id? */ + f->timeouttime = DEFTIMEOUT; + f->maxconfreqtransmits = DEFMAXCONFREQS; + f->maxtermtransmits = DEFMAXTERMREQS; + f->maxnakloops = DEFMAXNAKLOOPS; +} + + +/* + * fsm_lowerup - The lower layer is up. + */ +void +fsm_lowerup(f) + fsm *f; +{ + switch( f->state ){ + case INITIAL: + f->state = CLOSED; + break; + + case STARTING: + if( f->flags & OPT_SILENT ) + f->state = STOPPED; + else { + /* Send an initial configure-request */ + fsm_sconfreq(f, 0); + f->state = REQSENT; + } + break; + + default: + FSMDEBUG((LOG_INFO, "%s: Up event in state %d!", + PROTO_NAME(f), f->state)); + } +} + + +/* + * fsm_lowerdown - The lower layer is down. + * + * Cancel all timeouts and inform upper layers. + */ +void +fsm_lowerdown(f) + fsm *f; +{ + switch( f->state ){ + case CLOSED: + f->state = INITIAL; + break; + + case STOPPED: + f->state = STARTING; + if( f->callbacks->starting ) + (*f->callbacks->starting)(f); + break; + + case CLOSING: + f->state = INITIAL; + UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */ + break; + + case STOPPING: + case REQSENT: + case ACKRCVD: + case ACKSENT: + f->state = STARTING; + UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */ + break; + + case OPENED: + if( f->callbacks->down ) + (*f->callbacks->down)(f); + f->state = STARTING; + break; + + default: + FSMDEBUG((LOG_INFO, "%s: Down event in state %d!", + PROTO_NAME(f), f->state)); + } +} + + +/* + * fsm_open - Link is allowed to come up. + */ +void +fsm_open(f) + fsm *f; +{ + switch( f->state ){ + case INITIAL: + f->state = STARTING; + if( f->callbacks->starting ) + (*f->callbacks->starting)(f); + break; + + case CLOSED: + if( f->flags & OPT_SILENT ) + f->state = STOPPED; + else { + /* Send an initial configure-request */ + fsm_sconfreq(f, 0); + f->state = REQSENT; + } + break; + + case CLOSING: + f->state = STOPPING; + /* fall through */ + case STOPPED: + case OPENED: + if( f->flags & OPT_RESTART ){ + fsm_lowerdown(f); + fsm_lowerup(f); + } + break; + } +} + + +/* + * 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; +{ + switch( f->state ){ + case STARTING: + f->state = INITIAL; + break; + case STOPPED: + f->state = CLOSED; + break; + case STOPPING: + f->state = CLOSING; + break; + + case REQSENT: + case ACKRCVD: + case ACKSENT: + case OPENED: + if( f->state != OPENED ) + UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */ + else if( f->callbacks->down ) + (*f->callbacks->down)(f); /* Inform upper layers we're down */ + + /* Init restart counter, send Terminate-Request */ + f->retransmits = f->maxtermtransmits; + fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0); + TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime); + --f->retransmits; + + f->state = CLOSING; + break; + } +} + + +/* + * fsm_timeout - Timeout expired. + */ +static void +fsm_timeout(arg) + caddr_t arg; +{ + fsm *f = (fsm *) arg; + + switch (f->state) { + case CLOSING: + case STOPPING: + if( f->retransmits <= 0 ){ + /* + * We've waited for an ack long enough. Peer probably heard us. + */ + f->state = (f->state == CLOSING)? CLOSED: STOPPED; + if( f->callbacks->finished ) + (*f->callbacks->finished)(f); + } else { + /* Send Terminate-Request */ + fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0); + TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime); + --f->retransmits; + } + break; + + case REQSENT: + case ACKRCVD: + case ACKSENT: + if (f->retransmits <= 0) { + syslog(LOG_WARNING, "%s: timeout sending Config-Requests", + PROTO_NAME(f)); + f->state = STOPPED; + if( (f->flags & OPT_PASSIVE) == 0 && f->callbacks->finished ) + (*f->callbacks->finished)(f); + + } else { + /* Retransmit the configure-request */ + if (f->callbacks->retransmit) + (*f->callbacks->retransmit)(f); + fsm_sconfreq(f, 1); /* Re-send Configure-Request */ + if( f->state == ACKRCVD ) + f->state = REQSENT; + } + break; + + default: + FSMDEBUG((LOG_INFO, "%s: Timeout event in state %d!", + PROTO_NAME(f), f->state)); + } +} + + +/* + * 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 */ + + if( f->state == INITIAL || f->state == STARTING ){ + FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd packet in state %d.", + f->protocol, f->state)); + return; + } + + /* + * Action depends on code. + */ + switch (code) { + case CONFREQ: + fsm_rconfreq(f, id, inp, len); + break; + + case CONFACK: + fsm_rconfack(f, id, inp, len); + break; + + case CONFNAK: + case CONFREJ: + fsm_rconfnakrej(f, code, id, inp, len); + break; + + case TERMREQ: + fsm_rtermreq(f, id); + break; + + case TERMACK: + fsm_rtermack(f); + break; + + case CODEREJ: + fsm_rcoderej(f, inp, len); + break; + + default: + if( !f->callbacks->extcode + || !(*f->callbacks->extcode)(f, code, id, inp, len) ) + fsm_sdata(f, CODEREJ, ++f->id, inpacket, len + HEADERLEN); + break; + } +} + + +/* + * fsm_rconfreq - Receive Configure-Request. + */ +static void +fsm_rconfreq(f, id, inp, len) + fsm *f; + u_char id; + u_char *inp; + int len; +{ + u_char *outp; + int code, reject_if_disagree; + + FSMDEBUG((LOG_INFO, "fsm_rconfreq(%s): Rcvd id %d.", PROTO_NAME(f), id)); + switch( f->state ){ + case CLOSED: + /* Go away, we're closed */ + fsm_sdata(f, TERMACK, id, NULL, 0); + return; + case CLOSING: + case STOPPING: + return; + + case OPENED: + /* Go down and restart negotiation */ + if( f->callbacks->down ) + (*f->callbacks->down)(f); /* Inform upper layers */ + fsm_sconfreq(f, 0); /* Send initial Configure-Request */ + break; + + case STOPPED: + /* Negotiation started by our peer */ + fsm_sconfreq(f, 0); /* Send initial Configure-Request */ + f->state = REQSENT; + break; + } + + /* + * Pass the requested configuration options + * to protocol-specific code for checking. + */ + if (f->callbacks->reqci){ /* Check CI */ + reject_if_disagree = (f->nakloops >= f->maxnakloops); + code = (*f->callbacks->reqci)(f, inp, &len, reject_if_disagree); + } else if (len) + code = CONFREJ; /* Reject all CI */ + else + code = CONFACK; + + /* send the Ack, Nak or Rej to the peer */ + fsm_sdata(f, code, id, inp, len); + + if (code == CONFACK) { + if (f->state == ACKRCVD) { + UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */ + f->state = OPENED; + if (f->callbacks->up) + (*f->callbacks->up)(f); /* Inform upper layers */ + } else + f->state = ACKSENT; + f->nakloops = 0; + + } else { + /* we sent CONFACK or CONFREJ */ + if (f->state != ACKRCVD) + f->state = REQSENT; + if( code == CONFNAK ) + ++f->nakloops; + } +} + + +/* + * fsm_rconfack - Receive Configure-Ack. + */ +static void +fsm_rconfack(f, id, inp, len) + fsm *f; + int id; + u_char *inp; + int len; +{ + FSMDEBUG((LOG_INFO, "fsm_rconfack(%s): Rcvd id %d.", + PROTO_NAME(f), id)); + + if (id != f->reqid) /* Expected id? */ + return; /* Nope, toss... */ + if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len): (len == 0)) ){ + /* Ack is bad - ignore it */ + FSMDEBUG((LOG_INFO, "%s: received bad Ack (length %d)", + PROTO_NAME(f), len)); + return; + } + f->reqid = -1; + + switch (f->state) { + case CLOSED: + case STOPPED: + fsm_sdata(f, TERMACK, id, NULL, 0); + break; + + case REQSENT: + f->state = ACKRCVD; + f->retransmits = f->maxconfreqtransmits; + break; + + case ACKRCVD: + /* Huh? an extra Ack? oh well... */ + fsm_sconfreq(f, 0); + f->state = REQSENT; + break; + + case ACKSENT: + UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */ + f->state = OPENED; + f->retransmits = f->maxconfreqtransmits; + if (f->callbacks->up) + (*f->callbacks->up)(f); /* Inform upper layers */ + break; + + case OPENED: + /* Go down and restart negotiation */ + if (f->callbacks->down) + (*f->callbacks->down)(f); /* Inform upper layers */ + fsm_sconfreq(f, 0); /* Send initial Configure-Request */ + f->state = REQSENT; + break; + } +} + + +/* + * fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject. + */ +static void +fsm_rconfnakrej(f, code, id, inp, len) + fsm *f; + int code, id; + u_char *inp; + int len; +{ + int (*proc)(); + + FSMDEBUG((LOG_INFO, "fsm_rconfnakrej(%s): Rcvd id %d.", + PROTO_NAME(f), id)); + + if (id != f->reqid) /* Expected id? */ + return; /* Nope, toss... */ + proc = (code == CONFNAK)? f->callbacks->nakci: f->callbacks->rejci; + if( !proc || !proc(f, inp, len) ){ + /* Nak/reject is bad - ignore it */ + FSMDEBUG((LOG_INFO, "%s: received bad %s (length %d)", + PROTO_NAME(f), (code==CONFNAK? "Nak": "reject"), len)); + return; + } + f->reqid = -1; + + switch (f->state) { + case CLOSED: + case STOPPED: + fsm_sdata(f, TERMACK, id, NULL, 0); + break; + + case REQSENT: + case ACKSENT: + /* They didn't agree to what we wanted - try another request */ + UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */ + fsm_sconfreq(f, 0); /* Send Configure-Request */ + break; + + case ACKRCVD: + /* Got a Nak/reject when we had already had an Ack?? oh well... */ + fsm_sconfreq(f, 0); + f->state = REQSENT; + break; + + case OPENED: + /* Go down and restart negotiation */ + if (f->callbacks->down) + (*f->callbacks->down)(f); /* Inform upper layers */ + fsm_sconfreq(f, 0); /* Send initial Configure-Request */ + f->state = REQSENT; + break; + } +} + + +/* + * fsm_rtermreq - Receive Terminate-Req. + */ +static void +fsm_rtermreq(f, id) + fsm *f; + int id; +{ + FSMDEBUG((LOG_INFO, "fsm_rtermreq(%s): Rcvd id %d.", + PROTO_NAME(f), id)); + + switch (f->state) { + case ACKRCVD: + case ACKSENT: + f->state = REQSENT; /* Start over but keep trying */ + break; + + case OPENED: + syslog(LOG_INFO, "%s terminated at peer's request", PROTO_NAME(f)); + if (f->callbacks->down) + (*f->callbacks->down)(f); /* Inform upper layers */ + f->retransmits = 0; + f->state = STOPPING; + TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime); + break; + } + + fsm_sdata(f, TERMACK, id, NULL, 0); +} + + +/* + * fsm_rtermack - Receive Terminate-Ack. + */ +static void +fsm_rtermack(f) + fsm *f; +{ + FSMDEBUG((LOG_INFO, "fsm_rtermack(%s).", PROTO_NAME(f))); + + switch (f->state) { + case CLOSING: + f->state = CLOSED; + if( f->callbacks->finished ) + (*f->callbacks->finished)(f); + break; + case STOPPING: + f->state = STOPPED; + if( f->callbacks->finished ) + (*f->callbacks->finished)(f); + break; + + case ACKRCVD: + f->state = REQSENT; + break; + + case OPENED: + if (f->callbacks->down) + (*f->callbacks->down)(f); /* Inform upper layers */ + fsm_sconfreq(f, 0); + break; + } +} + + +/* + * fsm_rcoderej - Receive an Code-Reject. + */ +static void +fsm_rcoderej(f, inp, len) + fsm *f; + u_char *inp; + int len; +{ + u_char code, id; + + FSMDEBUG((LOG_INFO, "fsm_rcoderej(%s).", PROTO_NAME(f))); + + if (len < HEADERLEN) { + FSMDEBUG((LOG_INFO, "fsm_rcoderej: Rcvd short Code-Reject packet!")); + return; + } + GETCHAR(code, inp); + GETCHAR(id, inp); + syslog(LOG_WARNING, "%s: Rcvd Code-Reject for code %d, id %d", + PROTO_NAME(f), code, id); + + if( f->state == ACKRCVD ) + f->state = REQSENT; +} + + +/* + * fsm_protreject - Peer doesn't speak this protocol. + * + * Treat this as a catastrophic error (RXJ-). + */ +void +fsm_protreject(f) + fsm *f; +{ + switch( f->state ){ + case CLOSING: + UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */ + /* fall through */ + case CLOSED: + f->state = CLOSED; + if( f->callbacks->finished ) + (*f->callbacks->finished)(f); + break; + + case STOPPING: + case REQSENT: + case ACKRCVD: + case ACKSENT: + UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */ + /* fall through */ + case STOPPED: + f->state = STOPPED; + if( f->callbacks->finished ) + (*f->callbacks->finished)(f); + break; + + case OPENED: + if( f->callbacks->down ) + (*f->callbacks->down)(f); + + /* Init restart counter, send Terminate-Request */ + f->retransmits = f->maxtermtransmits; + fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0); + TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime); + --f->retransmits; + + f->state = STOPPING; + break; + + default: + FSMDEBUG((LOG_INFO, "%s: Protocol-reject event in state %d!", + PROTO_NAME(f), f->state)); + } +} + + +/* + * fsm_sconfreq - Send a Configure-Request. + */ +static void +fsm_sconfreq(f, retransmit) + fsm *f; + int retransmit; +{ + u_char *outp; + int outlen, cilen; + + if( f->state != REQSENT && f->state != ACKRCVD && f->state != ACKSENT ){ + /* Not currently negotiating - reset options */ + if( f->callbacks->resetci ) + (*f->callbacks->resetci)(f); + f->nakloops = 0; + } + + if( !retransmit ){ + /* New request - reset retransmission counter, use new ID */ + f->retransmits = f->maxconfreqtransmits; + f->reqid = ++f->id; + } + + /* + * Make up the request packet + */ + outp = outpacket_buf + DLLHEADERLEN + HEADERLEN; + if( f->callbacks->cilen && f->callbacks->addci ){ + cilen = (*f->callbacks->cilen)(f); + if( cilen > peer_mru[f->unit] - HEADERLEN ) + cilen = peer_mru[f->unit] - HEADERLEN; + if (f->callbacks->addci) + (*f->callbacks->addci)(f, outp, &cilen); + } else + cilen = 0; + + /* send the request to our peer */ + fsm_sdata(f, CONFREQ, f->reqid, outp, cilen); + + /* start the retransmit timer */ + --f->retransmits; + TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime); + + FSMDEBUG((LOG_INFO, "%s: sending Configure-Request, id %d", + PROTO_NAME(f), f->reqid)); +} + + +/* + * fsm_sdata - Send some data. + * + * Used for all packets sent to our peer by this module. + */ +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 */ + outp = outpacket_buf; + if (datalen > peer_mru[f->unit] - HEADERLEN) + datalen = peer_mru[f->unit] - HEADERLEN; + if (datalen && data != outp + DLLHEADERLEN + HEADERLEN) + BCOPY(data, outp + DLLHEADERLEN + HEADERLEN, datalen); + outlen = datalen + HEADERLEN; + MAKEHEADER(outp, f->protocol); + PUTCHAR(code, outp); + PUTCHAR(id, outp); + PUTSHORT(outlen, outp); + output(f->unit, outpacket_buf, outlen + DLLHEADERLEN); + + FSMDEBUG((LOG_INFO, "fsm_sdata(%s): Sent code %d, id %d.", + PROTO_NAME(f), code, id)); +} |
