ipcp.c

经典的ppp程序

}


/*
 * ipcp_init - Initialize IPCP.
 */
static void
ipcp_init(unit)
    int unit;
{
    fsm *f = &ipcp_fsm[unit];
    ipcp_options *wo = &ipcp_wantoptions[unit];
    ipcp_options *ao = &ipcp_allowoptions[unit];

    f->unit = unit;
    f->protocol = PPP_IPCP;
    f->callbacks = &ipcp_callbacks;
    fsm_init(&ipcp_fsm[unit]);

    memset(wo, 0, sizeof(*wo));
    memset(ao, 0, sizeof(*ao));

    wo->neg_addr = 1;
    wo->neg_vj = 1;
    wo->vj_protocol = IPCP_VJ_COMP;
    wo->maxslotindex = MAX_STATES - 1; /* really max index */
    wo->cflag = 1;


    /* max slots and slot-id compression are currently hardwired in */
    /* ppp_if.c to 16 and 1, this needs to be changed (among other */
    /* things) gmc */

    ao->neg_addr = 1;
    ao->neg_vj = 1;
    ao->maxslotindex = MAX_STATES - 1;
    ao->cflag = 1;

    /*
     * XXX These control whether the user may use the proxyarp
     * and defaultroute options.
     */
    ao->proxy_arp = 1;
    ao->default_route = 1;
}


/*
 * ipcp_open - IPCP is allowed to come up.
 */
static void
ipcp_open(unit)
    int unit;
{
    fsm_open(&ipcp_fsm[unit]);
}


/*
 * ipcp_close - Take IPCP down.
 */
static void
ipcp_close(unit, reason)
    int unit;
    char *reason;
{
    fsm_close(&ipcp_fsm[unit], reason);
}


/*
 * ipcp_lowerup - The lower layer is up.
 */
static void
ipcp_lowerup(unit)
    int unit;
{
    fsm_lowerup(&ipcp_fsm[unit]);
}


/*
 * ipcp_lowerdown - The lower layer is down.
 */
static void
ipcp_lowerdown(unit)
    int unit;
{
    fsm_lowerdown(&ipcp_fsm[unit]);
}


/*
 * ipcp_input - Input IPCP packet.
 */
static void
ipcp_input(unit, p, len)
    int unit;
    u_char *p;
    int len;
{
    fsm_input(&ipcp_fsm[unit], p, len);
}


/*
 * ipcp_protrej - A Protocol-Reject was received for IPCP.
 *
 * Pretend the lower layer went down, so we shut up.
 */
static void
ipcp_protrej(unit)
    int unit;
{
    fsm_lowerdown(&ipcp_fsm[unit]);
}


/*
 * ipcp_resetci - Reset our CI.
 * Called by fsm_sconfreq, Send Configure Request.
 */
static void
ipcp_resetci(f)
    fsm *f;
{
    ipcp_options *wo = &ipcp_wantoptions[f->unit];
    ipcp_options *go = &ipcp_gotoptions[f->unit];

    wo->req_addr = wo->neg_addr && ipcp_allowoptions[f->unit].neg_addr;
    if (wo->ouraddr == 0)
	wo->accept_local = 1;
    if (wo->hisaddr == 0)
	wo->accept_remote = 1;
    wo->req_dns1 = usepeerdns;	/* Request DNS addresses from the peer */
    wo->req_dns2 = usepeerdns;
    *go = *wo;
    if (!ask_for_local)
	go->ouraddr = 0;
    if (ip_choose_hook)
	ip_choose_hook(&wo->hisaddr);
}


/*
 * ipcp_cilen - Return length of our CI.
 * Called by fsm_sconfreq, Send Configure Request.
 */
static int
ipcp_cilen(f)
    fsm *f;
{
    ipcp_options *go = &ipcp_gotoptions[f->unit];
    ipcp_options *wo = &ipcp_wantoptions[f->unit];
    ipcp_options *ho = &ipcp_hisoptions[f->unit];

#define LENCIVJ(neg, old)	(neg ? (old? CILEN_COMPRESS : CILEN_VJ) : 0)
#define LENCIADDR(neg, old)	(neg ? (old? CILEN_ADDRS : CILEN_ADDR) : 0)
#define LENCIDNS(neg)		(neg ? (CILEN_ADDR) : 0)

    /*
     * First see if we want to change our options to the old
     * forms because we have received old forms from the peer.
     */
    if (wo->neg_addr && !go->neg_addr && !go->old_addrs) {
	/* use the old style of address negotiation */
	go->neg_addr = 1;
	go->old_addrs = 1;
    }
    if (wo->neg_vj && !go->neg_vj && !go->old_vj) {
	/* try an older style of VJ negotiation */
	/* use the old style only if the peer did */
	if (ho->neg_vj && ho->old_vj) {
	    go->neg_vj = 1;
	    go->old_vj = 1;
	    go->vj_protocol = ho->vj_protocol;
	}
    }

    return (LENCIADDR(go->neg_addr, go->old_addrs) +
	    LENCIVJ(go->neg_vj, go->old_vj) +
	    LENCIDNS(go->req_dns1) +
	    LENCIDNS(go->req_dns2)) ;
}


/*
 * ipcp_addci - Add our desired CIs to a packet.
 * Called by fsm_sconfreq, Send Configure Request.
 */
static void
ipcp_addci(f, ucp, lenp)
    fsm *f;
    u_char *ucp;
    int *lenp;
{
    ipcp_options *go = &ipcp_gotoptions[f->unit];
    int len = *lenp;

#define ADDCIVJ(opt, neg, val, old, maxslotindex, cflag) \
    if (neg) { \
	int vjlen = old? CILEN_COMPRESS : CILEN_VJ; \
	if (len >= vjlen) { \
	    PUTCHAR(opt, ucp); \
	    PUTCHAR(vjlen, ucp); \
	    PUTSHORT(val, ucp); \
	    if (!old) { \
		PUTCHAR(maxslotindex, ucp); \
		PUTCHAR(cflag, ucp); \
	    } \
	    len -= vjlen; \
	} else \
	    neg = 0; \
    }

#define ADDCIADDR(opt, neg, old, val1, val2) \
    if (neg) { \
	int addrlen = (old? CILEN_ADDRS: CILEN_ADDR); \
	if (len >= addrlen) { \
	    u_int32_t l; \
	    PUTCHAR(opt, ucp); \
	    PUTCHAR(addrlen, ucp); \
	    l = ntohl(val1); \
	    PUTLONG(l, ucp); \
	    if (old) { \
		l = ntohl(val2); \
		PUTLONG(l, ucp); \
	    } \
	    len -= addrlen; \
	} else \
	    neg = 0; \
    }

#define ADDCIDNS(opt, neg, addr) \
    if (neg) { \
	if (len >= CILEN_ADDR) { \
	    u_int32_t l; \
	    PUTCHAR(opt, ucp); \
	    PUTCHAR(CILEN_ADDR, ucp); \
	    l = ntohl(addr); \
	    PUTLONG(l, ucp); \
	    len -= CILEN_ADDR; \
	} else \
	    neg = 0; \
    }

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

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

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

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

    *lenp -= len;
}


/*
 * ipcp_ackci - Ack our CIs.
 * Called by fsm_rconfack, Receive Configure ACK.
 *
 * Returns:
 *	0 - Ack was bad.
 *	1 - Ack was good.
 */
static int
ipcp_ackci(f, p, len)
    fsm *f;
    u_char *p;
    int len;
{
    ipcp_options *go = &ipcp_gotoptions[f->unit];
    u_short cilen, citype, cishort;
    u_int32_t cilong;
    u_char cimaxslotindex, cicflag;

    /*
     * 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 ACKCIVJ(opt, neg, val, old, maxslotindex, cflag) \
    if (neg) { \
	int vjlen = old? CILEN_COMPRESS : CILEN_VJ; \
	if ((len -= vjlen) < 0) \
	    goto bad; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != vjlen || \
	    citype != opt)  \
	    goto bad; \
	GETSHORT(cishort, p); \
	if (cishort != val) \
	    goto bad; \
	if (!old) { \
	    GETCHAR(cimaxslotindex, p); \
	    if (cimaxslotindex != maxslotindex) \
		goto bad; \
	    GETCHAR(cicflag, p); \
	    if (cicflag != cflag) \
		goto bad; \
	} \
    }

#define ACKCIADDR(opt, neg, old, val1, val2) \
    if (neg) { \
	int addrlen = (old? CILEN_ADDRS: CILEN_ADDR); \
	u_int32_t l; \
	if ((len -= addrlen) < 0) \
	    goto bad; \
	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; \
	} \
    }

#define ACKCIDNS(opt, neg, addr) \
    if (neg) { \
	u_int32_t l; \
	if ((len -= CILEN_ADDR) < 0) \
	    goto bad; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_ADDR || citype != opt) \
	    goto bad; \
	GETLONG(l, p); \
	cilong = htonl(l); \
	if (addr != 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);

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

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

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

bad:
    IPCPDEBUG(("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.
 * Calback from fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject.
 *
 * 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 = &ipcp_gotoptions[f->unit];
    u_char cimaxslotindex, cicflag;
    u_char citype, cilen, *next;
    u_short cishort;
    u_int32_t ciaddr1, ciaddr2, l, cidnsaddr;
    ipcp_options no;		/* options we've seen Naks for */
    ipcp_options try;		/* options to request next time */

    BZERO(&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 \
    }

#define NAKCIDNS(opt, neg, code) \
    if (go->neg && \
	((cilen = p[1]) == CILEN_ADDR) && \
	len >= cilen && \
	p[0] == opt) { \
	len -= cilen; \
	INCPTR(2, p); \
	GETLONG(l, p); \
	cidnsaddr = htonl(l); \
	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((go->old_addrs? CI_ADDRS: CI_ADDR), neg_addr, go->old_addrs,
	      if (go->accept_local && ciaddr1) { /* Do we know our address? */
		  try.ouraddr = ciaddr1;
	      }
	      if (go->accept_remote && ciaddr2) { /* Does he know his? */
		  try.hisaddr = 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;
		}
	    }
	    );

    NAKCIDNS(CI_MS_DNS1, req_dns1,
	    try.dnsaddr[0] = cidnsaddr;
	    );

    NAKCIDNS(CI_MS_DNS2, req_dns2,
	    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( (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;