ipcp.c

vxworks的tcpip协议栈源码

	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != addrlen || \
	    citype != opt) \
	    goto bad; \
	GETLONG(l, p); \
	cilong = htonl(l); \
	if (val1 != cilong) \
	    goto bad; \
	if (old) { \
	    GETLONG(l, p); \
	    cilong = htonl(l); \
	    if (val2 != cilong) \
		goto bad; \
	} \
    }

    ACKCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), go->neg_addr,
	      go->old_addrs, go->ouraddr, go->hisaddr);

    ACKCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj,
	    go->maxslotindex, go->cflag);

    /*
     * If there are any remaining CIs, then this packet is bad.
     */
    if (len != 0)
	goto bad;
    return (1);

bad:
    IPCPDEBUG((LOG_INFO, "ipcp_ackci: received bad Ack!"));
    return (0);
}

/*
 * ipcp_nakci - Peer has sent a NAK for some of our CIs.
 * This should not modify any state if the Nak is bad
 * or if IPCP is in the OPENED state.
 *
 * Returns:
 *	0 - Nak was bad.
 *	1 - Nak was good.
 */
static int
ipcp_nakci(f, p, len)
    fsm *f;
    u_char *p;
    int len;
{
    ipcp_options *go = &ppp_if[f->unit]->ipcp_gotoptions;
    u_char cimaxslotindex = 0, cicflag = 0;
    u_char citype, cilen, *next;
    u_short cishort;
    u_long ciaddr1, ciaddr2, l;
    ipcp_options no;		/* options we've seen Naks for */
    ipcp_options try;		/* options to request next time */

    BZERO((char *)&no, sizeof(no));
    try = *go;

    /*
     * Any Nak'd CIs must be in exactly the same order that we sent.
     * Check packet length and CI length at each step.
     * If we find any deviations, then this packet is bad.
     */
#define NAKCIADDR(opt, neg, old, code) \
    if (go->neg && \
	len >= (cilen = (old? CILEN_ADDRS: CILEN_ADDR)) && \
	p[1] == cilen && \
	p[0] == opt) { \
	len -= cilen; \
	INCPTR(2, p); \
	GETLONG(l, p); \
	ciaddr1 = htonl(l); \
	if (old) { \
	    GETLONG(l, p); \
	    ciaddr2 = htonl(l); \
	    no.old_addrs = 1; \
	} else \
	    ciaddr2 = 0; \
	no.neg = 1; \
	code \
    }

#define NAKCIVJ(opt, neg, code) \
    if (go->neg && \
	((cilen = p[1]) == CILEN_COMPRESS || cilen == CILEN_VJ) && \
	len >= cilen && \
	p[0] == opt) { \
	len -= cilen; \
	INCPTR(2, p); \
	GETSHORT(cishort, p); \
	no.neg = 1; \
        code \
    }

    /*
     * Accept the peer's idea of {our,his} address, if different
     * from our idea, only if the accept_{local,remote} flag is set.
     */
    NAKCIADDR(CI_ADDR, neg_addr, go->old_addrs,
              if (go->accept_local && ciaddr1) { /* Do we know our address? */
                  try.ouraddr = ciaddr1;
                  IPCPDEBUG((LOG_INFO, "local IP address %s",
                             ip_ntoa(ciaddr1)));
              }
              if (go->accept_remote && ciaddr2) { /* Does he know his? */
                  try.hisaddr = ciaddr2;
                  IPCPDEBUG((LOG_INFO, "remote IP address %s",
                             ip_ntoa(ciaddr2)));
              }
              );

    /*
     * Accept the peer's value of maxslotindex provided that it
     * is less than what we asked for.  Turn off slot-ID compression
     * if the peer wants.  Send old-style compress-type option if
     * the peer wants.
     */
    NAKCIVJ(CI_COMPRESSTYPE, neg_vj,
	    if (cilen == CILEN_VJ) {
                GETCHAR(cimaxslotindex, p);
                GETCHAR(cicflag, p);
		if (cishort == IPCP_VJ_COMP) {
		    try.old_vj = 0;
		    if (cimaxslotindex < go->maxslotindex)
			try.maxslotindex = cimaxslotindex;
		    if (!cicflag)
			try.cflag = 0;
		} else {
		    try.neg_vj = 0;
		}
	    } else {
		if (cishort == IPCP_VJ_COMP || cishort == IPCP_VJ_COMP_OLD) {
		    try.old_vj = 1;
		    try.vj_protocol = cishort;
		} else {
		    try.neg_vj = 0;
		}
	    }
	    );

    /*
     * There may be remaining CIs, if the peer is requesting negotiation
     * on an option that we didn't include in our request packet.
     * If they want to negotiate about IP addresses, we comply.
     * If they want us to ask for compression, we refuse.
     */
    while (len > CILEN_VOID) {
	GETCHAR(citype, p);
	GETCHAR(cilen, p);
	if( (len -= cilen) < 0 )
	    goto bad;
	next = p + cilen - 2;

	switch (citype) {
	case CI_COMPRESSTYPE:
	    if (go->neg_vj || no.neg_vj ||
		(cilen != CILEN_VJ && cilen != CILEN_COMPRESS))
		goto bad;
	    no.neg_vj = 1;
	    break;
	case CI_ADDRS:
	    if ((go->neg_addr && go->old_addrs) || no.old_addrs
		|| cilen != CILEN_ADDRS)
		goto bad;
	    try.neg_addr = 1;
	    try.old_addrs = 1;
	    GETLONG(l, p);
	    ciaddr1 = htonl(l);
	    if (ciaddr1 && go->accept_local)
		try.ouraddr = ciaddr1;
	    GETLONG(l, p);
	    ciaddr2 = htonl(l);
	    if (ciaddr2 && go->accept_remote)
		try.hisaddr = ciaddr2;
	    no.old_addrs = 1;
	    break;
	case CI_ADDR:
	    if (go->neg_addr || no.neg_addr || cilen != CILEN_ADDR)
		goto bad;
	    try.neg_addr = 1;
	    try.old_addrs = 0;
	    GETLONG(l, p);
	    ciaddr1 = htonl(l);
	    if (ciaddr1 && go->accept_local)
		try.ouraddr = ciaddr1;
	    no.neg_addr = 1;
	    break;
	default:
	    goto bad;
	}
	p = next;
    }

    /* If there is still anything left, this packet is bad. */
    if (len != 0)
	goto bad;

    /*
     * OK, the Nak is good.  Now we can update state.
     */
    if (f->state != OPENED)
	*go = try;

    return 1;

bad:
    IPCPDEBUG((LOG_INFO, "ipcp_nakci: received bad Nak!"));
    return 0;
}


/*
 * ipcp_rejci - Reject some of our CIs.
 */
static int
ipcp_rejci(f, p, len)
    fsm *f;
    u_char *p;
    int len;
{
    ipcp_options *go = &ppp_if[f->unit]->ipcp_gotoptions;
    u_char cimaxslotindex, ciflag, cilen;
    u_short cishort;
    u_long cilong;
    ipcp_options try;		/* options to request next time */

    try = *go;

    /*
     * Bring down link if peer rejects the IPCP address configuration option,
     * since if the IP address can't be negotiated then the link is useless.
     */
    /*
     * Any Rejected CIs must be in exactly the same order that we sent.
     * Check packet length and CI length at each step.
     * If we find any deviations, then this packet is bad.
     */
#define REJCIADDR(opt, neg, old, val1, val2) \
    if (go->neg && \
	len >= (cilen = old? CILEN_ADDRS: CILEN_ADDR) && \
	p[1] == cilen && \
	p[0] == opt) { \
	u_long l; \
        die(f->unit, 1); /* not to protocol spec. see note in ipcp_close() */ \
	len -= cilen; \
	INCPTR(2, p); \
	GETLONG(l, p); \
	cilong = htonl(l); \
	/* Check rejected value. */ \
	if (cilong != val1) \
	    goto bad; \
	if (old) { \
	    GETLONG(l, p); \
	    cilong = htonl(l); \
	    /* Check rejected value. */ \
	    if (cilong != val2) \
		goto bad; \
	} \
	try.neg = 0; \
    }

#define REJCIVJ(opt, neg, val, old, maxslot, cflag) \
    if (go->neg && \
	p[1] == (old? CILEN_COMPRESS : CILEN_VJ) && \
	len >= p[1] && \
	p[0] == opt) { \
	len -= p[1]; \
	INCPTR(2, p); \
	GETSHORT(cishort, p); \
	/* Check rejected value. */  \
	if (cishort != val) \
	    goto bad; \
	if (!old) { \
	   GETCHAR(cimaxslotindex, p); \
	   if (cimaxslotindex != maxslot) \
	     goto bad; \
	   GETCHAR(ciflag, p); \
	   if (ciflag != cflag) \
	     goto bad; \
        } \
	try.neg = 0; \
     }

    REJCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), neg_addr,
	      go->old_addrs, go->ouraddr, go->hisaddr);

    REJCIVJ(CI_COMPRESSTYPE, neg_vj, go->vj_protocol, go->old_vj,
	    go->maxslotindex, go->cflag);

    /*
     * If there are any remaining CIs, then this packet is bad.
     */
    if (len != 0)
	goto bad;
    /*
     * Now we can update state.
     */
    if (f->state != OPENED)
	*go = try;
    return 1;

bad:
    IPCPDEBUG((LOG_INFO, "ipcp_rejci: received bad Reject!"));
    return 0;
}


/*
 * ipcp_reqci - Check the peer's requested CIs and send appropriate response.
 *
 * Returns: CONFACK, CONFNAK or CONFREJ and input packet modified
 * appropriately.  If reject_if_disagree is non-zero, doesn't return
 * CONFNAK; returns CONFREJ if it can't return CONFACK.
 */
static int
ipcp_reqci(f, inp, len, reject_if_disagree)
    fsm *f;
    u_char *inp;                /* Requested CIs */
    int *len;                   /* Length of requested CIs */
    int reject_if_disagree;
{
    ipcp_options *wo = &ppp_if[f->unit]->ipcp_wantoptions;
    ipcp_options *ho = &ppp_if[f->unit]->ipcp_hisoptions;
    ipcp_options *ao = &ppp_if[f->unit]->ipcp_allowoptions;
    ipcp_options *go = &ppp_if[f->unit]->ipcp_gotoptions;
    u_char *cip, *next;		/* Pointer to current and next CIs */
    u_short cilen, citype;	/* Parsed len, type */
    u_short cishort;		/* Parsed short value */
    u_long tl, ciaddr1, ciaddr2;/* Parsed address values */
    int rc = CONFACK;		/* Final packet return code */
    int orc;			/* Individual option return code */
    u_char *p;			/* Pointer to next char to parse */
    u_char *ucp = inp;		/* Pointer to current output char */
    int l = *len;		/* Length left */
    u_char maxslotindex, cflag;

    /*
     * Reset all his options.
     */
    BZERO((char *)ho, sizeof(*ho));
    
    /*
     * Process all his options.
     */
    next = inp;
    while (l) {
	orc = CONFACK;			/* Assume success */
	cip = p = next;			/* Remember begining of CI */
	if (l < 2 ||			/* Not enough data for CI header or */
	    p[1] < 2 ||			/*  CI length too small or */
	    p[1] > l) {			/*  CI length too big? */
	    IPCPDEBUG((LOG_INFO, "ipcp_reqci: bad CI length!"));
	    orc = CONFREJ;		/* Reject bad CI */
	    cilen = l;			/* Reject till end of packet */
	    l = 0;			/* Don't loop again */
	    goto endswitch;
	}
	GETCHAR(citype, p);		/* Parse CI type */
	GETCHAR(cilen, p);		/* Parse CI length */
	l -= cilen;			/* Adjust remaining length */
	next += cilen;			/* Step to next CI */

	switch (citype) {		/* Check CI type */
	case CI_ADDRS:
	    IPCPDEBUG((LOG_INFO, "ipcp: received ADDRS "));
	    if (!ao->neg_addr ||
		cilen != CILEN_ADDRS) {	/* Check CI length */
		orc = CONFREJ;		/* Reject CI */
		break;
	    }

	    /*
	     * If he has no address, or if we both have his address but
	     * disagree about it, then NAK it with our idea.
	     * In particular, if we don't know his address, but he does,
	     * then accept it.
	     */
	    GETLONG(tl, p);		/* Parse source address (his) */
	    ciaddr1 = htonl(tl);
	    IPCPDEBUG((LOG_INFO, "(%s:", ip_ntoa(ciaddr1)));
	    if (ciaddr1 != wo->hisaddr
                && (ciaddr1 == 0 || !wo->accept_remote)) {
		orc = CONFNAK;
		if (!reject_if_disagree) {
		    DECPTR(sizeof (long), p);
		    tl = ntohl(wo->hisaddr);
		    PUTLONG(tl, p);
		}
	    }

	    /*
	     * If he doesn't know our address, or if we both have our address
	     * but disagree about it, then NAK it with our idea.
	     */
	    GETLONG(tl, p);		/* Parse desination address (ours) */