ipcp.c

自己精简过的PPPD代码。在嵌入中应用可以更好的发挥。比原先的小了很多

		 try.dnsaddr[0] = cidnsaddr;
	     }
	     );

    NAKCIDNS(CI_MS_DNS2, req_dns2,
	     if (treat_as_reject) {
		 try.req_dns2 = 0;
	     } else {
		 try.dnsaddr[1] = cidnsaddr;
	     }
	     );

    /*
     * 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 ( cilen < CILEN_VOID || (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 = 0;
	    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.old_addrs = 0;
	    GETLONG(l, p);
	    ciaddr1 = htonl(l);
	    if (ciaddr1 && go->accept_local)
		try.ouraddr = ciaddr1;
	    if (try.ouraddr != 0)
		try.neg_addr = 1;
	    no.neg_addr = 1;
	    break;
	}
	p = next;
    }

    /*
     * OK, the Nak is good.  Now we can update state.
     * If there are any remaining options, we ignore them.
     */
    if (f->state != OPENED)
	*go = try;

    return 1;

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


/*
 * ipcp_rejci - Reject some of our CIs.
 * Callback from fsm_rconfnakrej.
 */
static int
ipcp_rejci(f, p, len)
    fsm *f;
    u_char *p;
    int len;
{
    ipcp_options *go = &ipcp_gotoptions[f->unit];
    u_char cimaxslotindex, ciflag, cilen;
    u_short cishort;
    u_int32_t cilong;
    ipcp_options try;		/* options to request next time */

    try = *go;
    /*
     * 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 REJCIADDRS(opt, neg, val1, val2) \
    if ((neg) && \
	(cilen = p[1]) == CILEN_ADDRS && \
	len >= cilen && \
	p[0] == opt) { \
	u_int32_t l; \
	len -= cilen; \
	INCPTR(2, p); \
	GETLONG(l, p); \
	cilong = htonl(l); \
	/* Check rejected value. */ \
	if (cilong != val1) \
	    goto bad; \
	GETLONG(l, p); \
	cilong = htonl(l); \
	/* Check rejected value. */ \
	if (cilong != val2) \
	    goto bad; \
	try.old_addrs = 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; \
     }

#define REJCIADDR(opt, neg, val) \
    if (go->neg && \
	(cilen = p[1]) == CILEN_ADDR && \
	len >= cilen && \
	p[0] == opt) { \
	u_int32_t l; \
	len -= cilen; \
	INCPTR(2, p); \
	GETLONG(l, p); \
	cilong = htonl(l); \
	/* Check rejected value. */ \
	if (cilong != val) \
	    goto bad; \
	try.neg = 0; \
    }

#define REJCIDNS(opt, neg, dnsaddr) \
    if (go->neg && \
	((cilen = p[1]) == CILEN_ADDR) && \
	len >= cilen && \
	p[0] == opt) { \
	u_int32_t l; \
	len -= cilen; \
	INCPTR(2, p); \
	GETLONG(l, p); \
	cilong = htonl(l); \
	/* Check rejected value. */ \
	if (cilong != dnsaddr) \
	    goto bad; \
	try.neg = 0; \
    }


    REJCIADDRS(CI_ADDRS, !go->neg_addr && go->old_addrs,
	       go->ouraddr, go->hisaddr);

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

    REJCIADDR(CI_ADDR, neg_addr, go->ouraddr);

    REJCIDNS(CI_MS_DNS1, req_dns1, go->dnsaddr[0]);

    REJCIDNS(CI_MS_DNS2, req_dns2, go->dnsaddr[1]);

    /*
     * 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(("ipcp_rejci: received bad Reject!"));
    return 0;
}


/*
 * ipcp_reqci - Check the peer's requested CIs and send appropriate response.
 * Callback from fsm_rconfreq, Receive Configure Request
 *
 * 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 = &ipcp_wantoptions[f->unit];
    ipcp_options *ho = &ipcp_hisoptions[f->unit];
    ipcp_options *ao = &ipcp_allowoptions[f->unit];
    u_char *cip, *next;		/* Pointer to current and next CIs */
    u_short cilen, citype;	/* Parsed len, type */
    u_short cishort;		/* Parsed short value */
    u_int32_t 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;
    int d;

    /*
     * Reset all his options.
     */
    BZERO(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(("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:
	    if (!ao->old_addrs || ho->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);
	    if (ciaddr1 != wo->hisaddr
		&& (ciaddr1 == 0 || !wo->accept_remote)) {
		orc = CONFNAK;
		if (!reject_if_disagree) {
		    DECPTR(sizeof(u_int32_t), p);
		    tl = ntohl(wo->hisaddr);
		    PUTLONG(tl, p);
		}
	    } else if (ciaddr1 == 0 && wo->hisaddr == 0) {
		/*
		 * If neither we nor he knows his address, reject the option.
		 */
		orc = CONFREJ;
		wo->req_addr = 0;	/* don't NAK with 0.0.0.0 later */
		break;
	    }

	    /*
	     * 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) */
	    ciaddr2 = htonl(tl);
	    if (ciaddr2 != wo->ouraddr) {
		if (ciaddr2 == 0 || !wo->accept_local) {
		    orc = CONFNAK;
		    if (!reject_if_disagree) {
			DECPTR(sizeof(u_int32_t), p);
			tl = ntohl(wo->ouraddr);
			PUTLONG(tl, p);
		    }
		} else {
		    wo->ouraddr = ciaddr2;	/* accept peer's idea */
		}
	    }

	    ho->old_addrs = 1;
	    ho->hisaddr = ciaddr1;
	    ho->ouraddr = ciaddr2;
	    break;

	case CI_ADDR:
	    if (!ao->neg_addr || ho->old_addrs ||
		cilen != CILEN_ADDR) {	/* 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);
	    if (ciaddr1 != wo->hisaddr
		&& (ciaddr1 == 0 || !wo->accept_remote)) {
		orc = CONFNAK;
		if (!reject_if_disagree) {
		    DECPTR(sizeof(u_int32_t), p);
		    tl = ntohl(wo->hisaddr);
		    PUTLONG(tl, p);
		}
	    } else if (ciaddr1 == 0 && wo->hisaddr == 0) {
		/*
		 * Don't ACK an address of 0.0.0.0 - reject it instead.
		 */
		orc = CONFREJ;
		wo->req_addr = 0;	/* don't NAK with 0.0.0.0 later */
		break;
	    }
	
	    ho->neg_addr = 1;
	    ho->hisaddr = ciaddr1;
	    break;

	case CI_MS_DNS1:
	case CI_MS_DNS2:
	    /* Microsoft primary or secondary DNS request */
	    d = citype == CI_MS_DNS2;

	    /* If we do not have a DNS address then we cannot send it */
	    if (ao->dnsaddr[d] == 0 ||
		cilen != CILEN_ADDR) {	/* Check CI length */
		orc = CONFREJ;		/* Reject CI */
		break;
	    }
	    GETLONG(tl, p);
	    if (htonl(tl) != ao->dnsaddr[d]) {
                DECPTR(sizeof(u_int32_t), p);
		tl = ntohl(ao->dnsaddr[d]);
		PUTLONG(tl, p);
		orc = CONFNAK;
            }
            break;

	case CI_MS_WINS1:
	case CI_MS_WINS2:
	    /* Microsoft primary or secondary WINS request */
	    d = citype == CI_MS_WINS2;

	    /* If we do not have a DNS address then we cannot send it */
	    if (ao->winsaddr[d] == 0 ||
		cilen != CILEN_ADDR) {	/* Check CI length */
		orc = CONFREJ;		/* Reject CI */
		break;
	    }
	    GETLONG(tl, p);
	    if (htonl(tl) != ao->winsaddr[d]) {
                DECPTR(sizeof(u_int32_t), p);
		tl = ntohl(ao->winsaddr[d]);
		PUTLONG(tl, p);
		orc = CONFNAK;
            }
            break;
	
	case CI_COMPRESSTYPE:
	    if (!ao->neg_vj ||
		(cilen != CILEN_VJ && cilen != CILEN_COMPRESS)) {
		orc = CONFREJ;
		break;
	    }
	    GETSHORT(cishort, p);

	    if (!(cishort == IPCP_VJ_COMP ||
		  (cishort == IPCP_VJ_COMP_OLD && cilen == CILEN_COMPRESS))) {
		orc = CONFREJ;
		break;
	    }

	    ho->neg_vj = 1;
	    ho->vj_protocol = cishort;
	    if (cilen == CILEN_VJ) {
		GETCHAR(maxslotindex, p);
		if (maxslotindex > ao->maxslotindex) { 
		    orc = CONFNAK;
		    if (!reject_if_disagree){
			DECPTR(1, p);
			PUTCHAR(ao->maxslotindex, p);
		    }
		}
		GETCHAR(cflag, p);
		if (cflag && !ao->cflag) {
		    orc = CONFNAK;
		    if (!reject_if_disagree){
			DECPTR(1, p);
			PUTCHAR(wo->cflag, p);
		    }
		}
		ho->maxslotindex = maxslotindex;
		ho->cflag = cflag;
	    } else {
		ho->old_vj = 1;
		ho->maxslotindex = MAX_STATES - 1;
		ho->cflag = 1;
	    }
	    break;

	default:
	    orc = CONFREJ;
	    break;
	}
endswitch:
	if (orc == CONFACK &&		/* Good CI */
	    rc != CONFACK)		/*  but prior CI wasnt? */
	    continue;			/* Don't send this one */

	if (orc == CONFNAK) {		/* Nak this CI? */
	    if (reject_if_disagree)	/* Getting fed up with sending NAKs? */
		orc = CONFREJ;		/* Get tough if so */
	    else {
		if (rc == CONFREJ)	/* Rejecting prior CI? */
		    continue;		/* Don't send this one */
		if (rc == CONFACK) {	/* Ack'd all prior CIs? */
		    rc = CONFNAK;	/* Not anymore... */
		    ucp = inp;		/* Backup */
		}
	    }
	}

	if (orc == CONFREJ &&		/* Reject this CI */
	    rc != CONFREJ) {		/*  but no prior ones? */
	    rc = CONFREJ;
	    ucp = inp;			/* Backup */
	}

	/* Need to move CI? */
	if (ucp != cip)
	    BCOPY(cip, ucp, cilen);	/* Move it */

	/* Update output pointer */
	INCPTR(cilen, ucp);
    }

    /*
     * If we aren't rejecting this packet, and we want to negotiate
     * their address, and they didn't send their address, then we
     * send a NAK with a CI_ADDR option appended.  We assume the
     * input buffer is long enough that we can append the extra
     * option safely.
     */
    if (rc != CONFREJ && !ho->neg_addr && !ho->old_addrs &&
	wo->req_addr && !reject_if_disagree) {
	if (rc == CONFACK) {
	    rc = CONFNAK;
	    ucp = inp;			/* reset pointer */
	    wo->req_addr = 0;		/* don't ask again */
	}
	PUTCHAR(CI_ADDR, ucp);
	PUTCHAR(CILEN_ADDR, ucp);
	tl = ntohl(wo->hisaddr);
	PUTLONG(tl, ucp);
    }

    *len = ucp - inp;			/* Compute output length */
    IPCPDEBUG(("ipcp: returning Configure-%s", CODENAME(rc)));
    return (rc);			/* Return final code */
}


/*
 * ip_check_options - check that any IP-related options are OK,
 * and assign appropriate defaults.
 */
static void
ip_check_options()
{
    struct hostent *hp;
    u_int32_t local;
    ipcp_options *wo = &ipcp_wantoptions[0];

    /*
     * Default our local IP address based on our hostname.
     * If local IP address already given, don't bother.
     */
    if (wo->ouraddr == 0 && !disable_defaultip) {
	/*
	 * Look up our hostname (possibly with domain name appended)
	 * and take the first IP address as our local IP address.
	 * If there isn't an IP address for our hostname, too bad.
	 */
	wo->accept_local = 1;	/* don't insist on this default value */
	if ((hp = gethostbyname(hostname)) != NULL) {
	    local = *(u_int32_t *)hp->h_addr;
	    if (local != 0 && !bad_ip_adrs(local))
		wo->ouraddr = local;
	}
    }
    ask_for_local = wo->ouraddr != 0 || !disable_defaultip;
}


/*
 * ip_demand_conf - configure the interface as though
 * IPCP were up, for use with dial-on-demand.
 */
static int
ip_demand_conf(u)
    int u;
{
    ipcp_options *wo = &ipcp_wantoptions[u];

    if (wo->hisaddr == 0) {
	/* make up an arbitrary address for the peer */
	wo->hisaddr = htonl(0x0a707070 + ifunit);
	wo->accept_remote = 1;
    }
    if (wo->ouraddr == 0) {
	/* make up an arbitrary address for us */
	wo->ouraddr = htonl(0x0a404040 + ifunit);
	wo->accept_local = 1;
	ask_for_local = 0;	/* don't tell the peer this address */
    }