fsm.c

PPPoE协议在Psos中的实现源代码

    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, (u_char)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( fsm *f, u_char id, u_char *inp, int len)
{
    FSMDEBUG((LOG_INFO, "fsm_rconfack(%s): Rcvd id %d.",
	      PROTO_NAME(f), id));

    if (id != f->reqid || f->seen_ack)		/* 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->seen_ack = 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 valid Ack? oh well... */
	UNTIMEOUT(fsm_timeout, (caddr_t) f);	/* Cancel timeout */
	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( fsm *f, u_char code, u_char id, u_char *inp, int len)
{
    int (*proc)(fsm *, u_char *, int);

    FSMDEBUG((LOG_INFO, "fsm_rconfnakrej(%s): Rcvd id %d.",
	      PROTO_NAME(f), id));

    if (id != f->reqid || f->seen_ack)	/* 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->seen_ack = 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... */
	UNTIMEOUT(fsm_timeout, (caddr_t) f);	/* Cancel timeout */
	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( fsm *f, u_char 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:
	UNTIMEOUT(fsm_timeout, (caddr_t) f);
	f->state = CLOSED;
	if( f->callbacks->finished )
	    (*f->callbacks->finished)(f);
	break;
    case STOPPING:
	UNTIMEOUT(fsm_timeout, (caddr_t) f);
	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;
    }

    f->seen_ack = 0;

    /*
     * Make up the request packet
     */
    outp = outpacket_buf + 10 + 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( fsm *f, u_char code, u_char id, u_char *data, int datalen)
{
    u_char *outp;
    int outlen,plen;

    /* Adjust length to be smaller than MTU */
    outp = outpacket_buf;
    if (datalen > peer_mru[f->unit] - HEADERLEN - 8)
	datalen = peer_mru[f->unit] - HEADERLEN - 8;
    if (datalen && data != outp + 10 + HEADERLEN)
	BCOPY(data, outp + 10 + HEADERLEN, (size_t) datalen);
    outlen = datalen + HEADERLEN;
    plen = outlen +2;
      
    PUTSHORT(ETH_PPPOE_SESSION, outp);
    PUTCHAR(0x11,outp); 
    PUTCHAR(CODE_SESS, outp);
    PUTSHORT(Connection.session, outp);
    PUTSHORT(plen, outp);
    
    PUTSHORT(f->protocol, outp);	
    PUTCHAR(code, outp);
    PUTCHAR(id, outp);
    PUTSHORT(outlen, outp);
    
    output(Connection.peerEth, f->unit, outpacket_buf, plen+8);

    FSMDEBUG((LOG_INFO, "fsm_sdata(%s): Sent code %d, id %d.",
	      PROTO_NAME(f), code, id));
}