ipxcp.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

}


/*
 * ipxcp_resetci - Reset our CI.
 */
static void
ipxcp_resetci(f)
    fsm *f;
{
    wo->req_node = wo->neg_node && ao->neg_node;
    wo->req_nn	 = wo->neg_nn	&& ao->neg_nn;

    if (wo->our_network == 0) {
	wo->neg_node	   = 1;
	ao->accept_network = 1;
    }
/*
 * If our node number is zero then change it.
 */
    if (zero_node (wo->our_node)) {
	inc_node (wo->our_node);
	ao->accept_local = 1;
	wo->neg_node	 = 1;
    }
/*
 * If his node number is zero then change it.
 */
    if (zero_node (wo->his_node)) {
	inc_node (wo->his_node);
	ao->accept_remote = 1;
    }
/*
 * If no routing agent was specified then we do RIP/SAP according to the
 * RFC documents. If you have specified something then OK. Otherwise, we
 * do RIP/SAP.
 */
    if (ao->router == 0) {
	ao->router |= BIT(RIP_SAP);
	wo->router |= BIT(RIP_SAP);
    }

    /* Always specify a routing protocol unless it was REJected. */
    wo->neg_router = 1;
/*
 * Start with these default values
 */
    *go = *wo;
}

/*
 * ipxcp_cilen - Return length of our CI.
 */

static int
ipxcp_cilen(f)
    fsm *f;
{
    int len;

    len	 = go->neg_nn	    ? CILEN_NETN     : 0;
    len += go->neg_node	    ? CILEN_NODEN    : 0;
    len += go->neg_name	    ? CILEN_NAME + strlen (go->name) - 1 : 0;

    /* RFC says that defaults should not be included. */
    if (go->neg_router && to_external(go->router) != RIP_SAP)
        len += CILEN_PROTOCOL;

    return (len);
}


/*
 * ipxcp_addci - Add our desired CIs to a packet.
 */
static void
ipxcp_addci(f, ucp, lenp)
    fsm *f;
    u_char *ucp;
    int *lenp;
{
/*
 * Add the options to the record.
 */
    if (go->neg_nn) {
	PUTCHAR (IPX_NETWORK_NUMBER, ucp);
	PUTCHAR (CILEN_NETN, ucp);
	PUTLONG (go->our_network, ucp);
    }

    if (go->neg_node) {
	int indx;
	PUTCHAR (IPX_NODE_NUMBER, ucp);
	PUTCHAR (CILEN_NODEN, ucp);
	for (indx = 0; indx < sizeof (go->our_node); ++indx)
	    PUTCHAR (go->our_node[indx], ucp);
    }

    if (go->neg_name) {
	int cilen = strlen (go->name);
	int indx;
	PUTCHAR (IPX_ROUTER_NAME, ucp);
	PUTCHAR (CILEN_NAME + cilen - 1, ucp);
	for (indx = 0; indx < cilen; ++indx)
	    PUTCHAR (go->name [indx], ucp);
    }

    if (go->neg_router) {
        short external = to_external (go->router);
	if (external != RIP_SAP) {
	    PUTCHAR  (IPX_ROUTER_PROTOCOL, ucp);
	    PUTCHAR  (CILEN_PROTOCOL,      ucp);
	    PUTSHORT (external,            ucp);
	}
    }
}

/*
 * ipxcp_ackci - Ack our CIs.
 *
 * Returns:
 *	0 - Ack was bad.
 *	1 - Ack was good.
 */
static int
ipxcp_ackci(f, p, len)
    fsm *f;
    u_char *p;
    int len;
{
    u_short cilen, citype, cishort;
    u_char cichar;
    u_int32_t cilong;

#define ACKCIVOID(opt, neg) \
    if (neg) { \
	if ((len -= CILEN_VOID) < 0) \
	    break; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_VOID || \
	    citype != opt) \
	    break; \
    }

#define ACKCICOMPLETE(opt,neg)	ACKCIVOID(opt, neg)

#define ACKCICHARS(opt, neg, val, cnt) \
    if (neg) { \
	int indx, count = cnt; \
	len -= (count + 2); \
	if (len < 0) \
	    break; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != (count + 2) || \
	    citype != opt) \
	    break; \
	for (indx = 0; indx < count; ++indx) {\
	    GETCHAR(cichar, p); \
	    if (cichar != ((u_char *) &val)[indx]) \
	       break; \
	}\
	if (indx != count) \
	    break; \
    }

#define ACKCINODE(opt,neg,val) ACKCICHARS(opt,neg,val,sizeof(val))
#define ACKCINAME(opt,neg,val) ACKCICHARS(opt,neg,val,strlen(val))

#define ACKCINETWORK(opt, neg, val) \
    if (neg) { \
	if ((len -= CILEN_NETN) < 0) \
	    break; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_NETN || \
	    citype != opt) \
	    break; \
	GETLONG(cilong, p); \
	if (cilong != val) \
	    break; \
    }

#define ACKCIPROTO(opt, neg, val) \
    if (neg) { \
	if (len < 2) \
	    break; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_PROTOCOL || citype != opt) \
	    break; \
	len -= cilen; \
	if (len < 0) \
	    break; \
	GETSHORT(cishort, p); \
	if (cishort != to_external (val) || cishort == RIP_SAP) \
	    break; \
      }
/*
 * Process the ACK frame in the order in which the frame was assembled
 */
    do {
	ACKCINETWORK  (IPX_NETWORK_NUMBER,  go->neg_nn,	    go->our_network);
	ACKCINODE     (IPX_NODE_NUMBER,	    go->neg_node,   go->our_node);
	ACKCINAME     (IPX_ROUTER_NAME,	    go->neg_name,   go->name);
	if (len > 0)
		ACKCIPROTO    (IPX_ROUTER_PROTOCOL, go->neg_router, go->router);
/*
 * This is the end of the record.
 */
	if (len == 0)
	    return (1);
    } while (0);
/*
 * The frame is invalid
 */
    IPXCPDEBUG(("ipxcp_ackci: received bad Ack!"));
    return (0);
}

/*
 * ipxcp_nakci - Peer has sent a NAK for some of our CIs.
 * This should not modify any state if the Nak is bad
 * or if IPXCP is in the OPENED state.
 *
 * Returns:
 *	0 - Nak was bad.
 *	1 - Nak was good.
 */

static int
ipxcp_nakci(f, p, len, treat_as_reject)
    fsm *f;
    u_char *p;
    int len;
    int treat_as_reject;
{
    u_char citype, cilen, *next;
    u_short s;
    u_int32_t l;
    ipxcp_options no;		/* options we've seen Naks for */
    ipxcp_options try;		/* options to request next time */

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

    while (len >= CILEN_VOID) {
	GETCHAR (citype, p);
	GETCHAR (cilen,	 p);
	len -= cilen;
	if (cilen < CILEN_VOID || len < 0)
	    goto bad;
	next = &p [cilen - CILEN_VOID];

	switch (citype) {
	case IPX_NETWORK_NUMBER:
	    if (!go->neg_nn || no.neg_nn || (cilen != CILEN_NETN))
		goto bad;
	    no.neg_nn = 1;

	    GETLONG(l, p);
	    if (treat_as_reject)
		try.neg_nn = 0;
	    else if (l && ao->accept_network)
		try.our_network = l;
	    break;

	case IPX_NODE_NUMBER:
	    if (!go->neg_node || no.neg_node || (cilen != CILEN_NODEN))
		goto bad;
	    no.neg_node = 1;

	    if (treat_as_reject)
		try.neg_node = 0;
	    else if (!zero_node (p) && ao->accept_local &&
		     ! compare_node (p, ho->his_node))
		copy_node (p, try.our_node);
	    break;

	    /* This has never been sent. Ignore the NAK frame */
	case IPX_COMPRESSION_PROTOCOL:
	    goto bad;

	case IPX_ROUTER_PROTOCOL:
	    if (!go->neg_router || (cilen < CILEN_PROTOCOL))
		goto bad;

	    GETSHORT (s, p);
	    if (s > 15)         /* This is just bad, but ignore for now. */
	        break;

	    s = BIT(s);
	    if (no.router & s)  /* duplicate NAKs are always bad */
		goto bad;

	    if (no.router == 0) /* Reset on first NAK only */
		try.router = 0;

	    no.router      |= s;
	    try.router     |= s;
	    try.neg_router  = 1;
	    break;

	    /* These, according to the RFC, must never be NAKed. */
	case IPX_ROUTER_NAME:
	case IPX_COMPLETE:
	    goto bad;

	    /* These are for options which we have not seen. */
	default:
	    break;
	}
	p = next;
    }

    /*
     * Do not permit the peer to force a router protocol which we do not
     * support. However, default to the condition that will accept "NONE".
     */
    try.router &= (ao->router | BIT(IPX_NONE));
    if (try.router == 0 && ao->router != 0)
	try.router = BIT(IPX_NONE);

    if (try.router != 0)
        try.neg_router = 1;
    
    /*
     * OK, the Nak is good.  Now we can update state.
     * If there are any options left, we ignore them.
     */
    if (f->state != OPENED)
	*go = try;

    return 1;

bad:
    IPXCPDEBUG(("ipxcp_nakci: received bad Nak!"));
    return 0;
}

/*
 * ipxcp_rejci - Reject some of our CIs.
 */
static int
ipxcp_rejci(f, p, len)
    fsm *f;
    u_char *p;
    int len;
{
    u_short cilen, citype, cishort;
    u_char cichar;
    u_int32_t cilong;
    ipxcp_options try;		/* options to request next time */

#define REJCINETWORK(opt, neg, val) \
    if (neg && p[0] == opt) { \
	if ((len -= CILEN_NETN) < 0) \
	    break; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_NETN || \
	    citype != opt) \
	    break; \
	GETLONG(cilong, p); \
	if (cilong != val) \
	    break; \
	neg = 0; \
    }

#define REJCICHARS(opt, neg, val, cnt) \
    if (neg && p[0] == opt) { \
	int indx, count = cnt; \
	len -= (count + 2); \
	if (len < 0) \
	    break; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != (count + 2) || \
	    citype != opt) \
	    break; \
	for (indx = 0; indx < count; ++indx) {\
	    GETCHAR(cichar, p); \
	    if (cichar != ((u_char *) &val)[indx]) \
	       break; \
	}\
	if (indx != count) \
	    break; \
	neg = 0; \
    }

#define REJCINODE(opt,neg,val) REJCICHARS(opt,neg,val,sizeof(val))
#define REJCINAME(opt,neg,val) REJCICHARS(opt,neg,val,strlen(val))

#define REJCIVOID(opt, neg) \
    if (neg && p[0] == opt) { \
	if ((len -= CILEN_VOID) < 0) \
	    break; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_VOID || citype != opt) \
	    break; \
	neg = 0; \
    }

/* a reject for RIP/SAP is invalid since we don't send it and you can't
   reject something which is not sent. (You can NAK, but you can't REJ.) */
#define REJCIPROTO(opt, neg, val, bit) \
    if (neg && p[0] == opt) { \
	if ((len -= CILEN_PROTOCOL) < 0) \
	    break; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_PROTOCOL) \
	    break; \
	GETSHORT(cishort, p); \
	if (cishort != to_external (val) || cishort == RIP_SAP) \
	    break; \
	neg = 0; \
    }
/*
 * 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.
 */
    try = *go;

    do {
	REJCINETWORK (IPX_NETWORK_NUMBER,  try.neg_nn,	   try.our_network);
	REJCINODE    (IPX_NODE_NUMBER,	   try.neg_node,   try.our_node);
	REJCINAME    (IPX_ROUTER_NAME,	   try.neg_name,   try.name);
	REJCIPROTO   (IPX_ROUTER_PROTOCOL, try.neg_router, try.router, 0);
/*
 * This is the end of the record.
 */
	if (len == 0) {
	    if (f->state != OPENED)
		*go = try;
	    return (1);
	}
    } while (0);
/*
 * The frame is invalid at this point.
 */
    IPXCPDEBUG(("ipxcp_rejci: received bad Reject!"));
    return 0;
}

/*
 * ipxcp_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
ipxcp_reqci(f, inp, len, reject_if_disagree)
    fsm *f;
    u_char *inp;		/* Requested CIs */
    int *len;			/* Length of requested CIs */
    int reject_if_disagree;
{
    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 cinetwork;	/* 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 */

    /*
     * 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? */
	    IPXCPDEBUG(("ipxcp_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 */
/*
 * The network number must match. Choose the larger of the two.
 */
	case IPX_NETWORK_NUMBER:
	    /* if we wont negotiate the network number or the length is wrong
	       then reject the option */
	    if ( !ao->neg_nn || cilen != CILEN_NETN ) {
		orc = CONFREJ;
		break;		
	    }
	    GETLONG(cinetwork, p);

	    /* If the network numbers match then acknowledge them. */
	    if (cinetwork != 0) {
		ho->his_network = cinetwork;
		ho->neg_nn	= 1;
		if (wo->our_network == cinetwork)
		    break;
/*
 * If the network number is not given or we don't accept their change or
 * the network number is too small then NAK it.
 */
		if (! ao->accept_network || cinetwork < wo->our_network) {
		    DECPTR (sizeof (u_int32_t), p);
		    PUTLONG (wo->our_network, p);
		    orc = CONFNAK;
		}
		break;
	    }
/*
 * The peer sent '0' for the network. Give it ours if we have one.
 */
	    if (go->our_network != 0) {
		DECPTR (sizeof (u_int32_t), p);