pk_subr.c

早期freebsd实现

				pkp -> pk_chan[ni] -> lcd_lcn = ni;
			}
	}

	for (i = 1; i <= pkp -> pk_maxlcn; ++i)
		if ((lcp = pkp -> pk_chan[i]) != NULL) {
			/* if (lcp -> lcd_so)
				soisconnecting (lcp -> lcd_so); */
			lcp -> lcd_template = pk_template (lcp -> lcd_lcn, X25_CALL);
			pk_callrequest (lcp, lcp -> lcd_ceaddr, pkp -> pk_xcp);
			(*pkp -> pk_ia -> ia_start) (lcp);
		}
}

struct bcdinfo {
	octet *cp;
	unsigned posn;
};
/* 
 *  Build the rest of the CALL REQUEST packet. Fill in calling
 *  address, facilities fields and the user data field.
 */

pk_callrequest (lcp, sa, xcp)
struct pklcd *lcp;
register struct sockaddr_x25 *sa;
register struct x25config *xcp;
{
	register struct x25_calladdr *a;
	register struct mbuf *m = lcp -> lcd_template;
	register struct x25_packet *xp = mtod (m, struct x25_packet *);
	struct bcdinfo b;

	if (lcp -> lcd_flags & X25_DBIT)
		X25SBITS(xp -> bits, d_bit, 1);
	a = (struct x25_calladdr *) &xp -> packet_data;
	b.cp = (octet *) a -> address_field;
	b.posn = 0;
	X25SBITS(a -> addrlens, called_addrlen, to_bcd (&b, sa, xcp));
	X25SBITS(a -> addrlens, calling_addrlen, to_bcd (&b, &xcp -> xc_addr, xcp));
	if (b.posn & 0x01)
		*b.cp++ &= 0xf0;
	m -> m_pkthdr.len = m -> m_len += b.cp - (octet *) a;

	if (lcp -> lcd_facilities) {
		m -> m_pkthdr.len += 
			(m -> m_next = lcp -> lcd_facilities) -> m_pkthdr.len;
		lcp -> lcd_facilities = 0;
	} else
		pk_build_facilities (m, sa, (int)xcp -> xc_type);

	m_copyback (m, m -> m_pkthdr.len, sa -> x25_udlen, sa -> x25_udata);
}

pk_build_facilities (m, sa, type)
register struct mbuf *m;
struct sockaddr_x25 *sa;
{
	register octet *cp;
	register octet *fcp;
	register int revcharge;

	cp = mtod (m, octet *) + m -> m_len;
	fcp = cp + 1;
	revcharge = sa -> x25_opts.op_flags & X25_REVERSE_CHARGE ? 1 : 0;
	/*
	 * This is specific to Datapac X.25(1976) DTEs.  International
	 * calls must have the "hi priority" bit on.
	 */
	if (type == X25_1976 && sa -> x25_opts.op_psize == X25_PS128)
		revcharge |= 02;
	if (revcharge) {
		*fcp++ = FACILITIES_REVERSE_CHARGE;
		*fcp++ = revcharge;
	}
	switch (type) {
	case X25_1980:
	case X25_1984:
		*fcp++ = FACILITIES_PACKETSIZE;
		*fcp++ = sa -> x25_opts.op_psize;
		*fcp++ = sa -> x25_opts.op_psize;

		*fcp++ = FACILITIES_WINDOWSIZE;
		*fcp++ = sa -> x25_opts.op_wsize;
		*fcp++ = sa -> x25_opts.op_wsize;
	}
	*cp = fcp - cp - 1;
	m -> m_pkthdr.len = (m -> m_len += *cp + 1);
}

to_bcd (b, sa, xcp)
register struct bcdinfo *b;
struct sockaddr_x25 *sa;
register struct x25config *xcp;
{
	register char *x = sa -> x25_addr;
	unsigned start = b -> posn;
	/*
	 * The nodnic and prepnd0 stuff looks tedious,
	 * but it does allow full X.121 addresses to be used,
	 * which is handy for routing info (& OSI type 37 addresses).
	 */
	if (xcp -> xc_addr.x25_net && (xcp -> xc_nodnic || xcp -> xc_prepnd0)) {
		char dnicname[sizeof (long) * NBBY/3 + 2];
		register char *p = dnicname;

		sprintf (p, "%d", xcp -> xc_addr.x25_net & 0x7fff);
		for (; *p; p++) /* *p == 0 means dnic matched */
			if ((*p ^ *x++) & 0x0f)
				break;
		if (*p || xcp -> xc_nodnic == 0)
			x = sa -> x25_addr;
		if (*p && xcp -> xc_prepnd0) {
			if ((b -> posn)++ & 0x01)
				*(b -> cp)++;
			else
				*(b -> cp) = 0;
		}
	}
	while (*x)
		if ((b -> posn)++ & 0x01)
			*(b -> cp)++ |= *x++ & 0x0F;
		else
			*(b -> cp) = *x++ << 4;
	return ((b -> posn) - start);
}

/* 
 *  This routine gets the  first available logical channel number.  The
 *  search is 
 *  		- from the highest number to lowest number if playing DTE, and
 *		- from lowest to highest number if playing DCE.
 */

pk_getlcn (pkp)
register struct pkcb *pkp;
{
	register int i;

	if (pkp -> pk_chan == 0)
		return (0);
	if ( pkp -> pk_dxerole & DTE_PLAYDCE ) {
		for (i = 1; i <= pkp -> pk_maxlcn; ++i)
			if (pkp -> pk_chan[i] == NULL)
				break;
	} else { 
		for (i = pkp -> pk_maxlcn; i > 0; --i)
			if (pkp -> pk_chan[i] == NULL)
				break;
	}
	i = ( i > pkp -> pk_maxlcn ? 0 : i );
	return (i);
}

/* 
 *  This procedure sends a CLEAR request packet. The lc state is
 *  set to "SENT_CLEAR". 
 */

pk_clear (lcp, diagnostic, abortive)
register struct pklcd *lcp;
{
	register struct mbuf *m = pk_template (lcp -> lcd_lcn, X25_CLEAR);

	m -> m_len += 2;
	m -> m_pkthdr.len += 2;
	mtod (m, struct x25_packet *) -> packet_data = 0;
	mtod (m, octet *)[4] = diagnostic;
	if (lcp -> lcd_facilities) {
		m -> m_next = lcp -> lcd_facilities;
		m -> m_pkthdr.len += m -> m_next -> m_len;
		lcp -> lcd_facilities = 0;
	}
	if (abortive)
		lcp -> lcd_template = m;
	else {
		struct socket *so = lcp -> lcd_so;
		struct sockbuf *sb = so ? & so -> so_snd : & lcp -> lcd_sb;
		sbappendrecord (sb, m);
	}
	pk_output (lcp);

}

/*
 * This procedure generates RNR's or RR's to inhibit or enable
 * inward data flow, if the current state changes (blocked ==> open or
 * vice versa), or if forced to generate one.  One forces RNR's to ack data.  
 */
pk_flowcontrol (lcp, inhibit, forced)
register struct pklcd *lcp;
{
	inhibit = (inhibit != 0);
	if (lcp == 0 || lcp -> lcd_state != DATA_TRANSFER ||
	    (forced == 0 && lcp -> lcd_rxrnr_condition == inhibit))
		return;
	lcp -> lcd_rxrnr_condition = inhibit;
	lcp -> lcd_template =
		pk_template (lcp -> lcd_lcn, inhibit ? X25_RNR : X25_RR);
	pk_output (lcp);
}

/* 
 *  This procedure sends a RESET request packet. It re-intializes
 *  virtual circuit.
 */

static
pk_reset (lcp, diagnostic)
register struct pklcd *lcp;
{
	register struct mbuf *m;
	register struct socket *so = lcp -> lcd_so;

	if (lcp -> lcd_state != DATA_TRANSFER)
		return;

	if (so)
		so -> so_error = ECONNRESET;
	lcp -> lcd_reset_condition = TRUE;

	/* Reset all the control variables for the channel. */
	pk_flush (lcp);
	lcp -> lcd_window_condition = lcp -> lcd_rnr_condition =
		lcp -> lcd_intrconf_pending = FALSE;
	lcp -> lcd_rsn = MODULUS - 1;
	lcp -> lcd_ssn = 0;
	lcp -> lcd_output_window = lcp -> lcd_input_window =
		lcp -> lcd_last_transmitted_pr = 0;
	m = lcp -> lcd_template = pk_template (lcp -> lcd_lcn, X25_RESET);
	m -> m_pkthdr.len = m -> m_len += 2;
	mtod (m, struct x25_packet *) -> packet_data = 0;
	mtod (m, octet *)[4] = diagnostic;
	pk_output (lcp);

}

/*
 * This procedure frees all data queued for output or delivery on a
 *  virtual circuit.
 */

pk_flush (lcp)
register struct pklcd *lcp;
{
	register struct socket *so;

	if (lcp -> lcd_template)
		m_freem (lcp -> lcd_template);

	if (lcp -> lcd_cps) {
		m_freem (lcp -> lcd_cps);
		lcp -> lcd_cps = 0;
	}
	if (lcp -> lcd_facilities) {
		m_freem (lcp -> lcd_facilities);
		lcp -> lcd_facilities = 0;
	}
	if (so = lcp -> lcd_so) 
		sbflush (&so -> so_snd);
	else 
		sbflush (&lcp -> lcd_sb);
}

/* 
 *  This procedure handles all local protocol procedure errors.
 */

pk_procerror (error, lcp, errstr, diagnostic)
register struct pklcd *lcp;
char *errstr;
{

	pk_message (lcp -> lcd_lcn, lcp -> lcd_pkp -> pk_xcp, errstr);

	switch (error) {
	case CLEAR: 
		if (lcp -> lcd_so) {
			lcp -> lcd_so -> so_error = ECONNABORTED;
			soisdisconnecting (lcp -> lcd_so);
		}
		pk_clear (lcp, diagnostic, 1);
		break;

	case RESET: 
		pk_reset (lcp, diagnostic);
	}
}

/* 
 *  This procedure is called during the DATA TRANSFER state to check 
 *  and  process  the P(R) values  received  in the DATA,  RR OR RNR
 *  packets.
 */

pk_ack (lcp, pr)
struct pklcd *lcp;
unsigned pr;
{
	register struct socket *so = lcp -> lcd_so;

	if (lcp -> lcd_output_window == pr)
		return (PACKET_OK);
	if (lcp -> lcd_output_window < lcp -> lcd_ssn) {
		if (pr < lcp -> lcd_output_window || pr > lcp -> lcd_ssn) {
			pk_procerror (RESET, lcp,
				"p(r) flow control error", 2);
			return (ERROR_PACKET);
		}
	}
	else {
		if (pr < lcp -> lcd_output_window && pr > lcp -> lcd_ssn) {
			pk_procerror (RESET, lcp,
				"p(r) flow control error #2", 2);
			return (ERROR_PACKET);
		}
	}

	lcp -> lcd_output_window = pr;		/* Rotate window. */
	if (lcp -> lcd_window_condition == TRUE)
		lcp -> lcd_window_condition = FALSE;

	if (so && ((so -> so_snd.sb_flags & SB_WAIT) || 
		   (so -> so_snd.sb_flags & SB_NOTIFY)))
		sowwakeup (so);

	return (PACKET_OK);
}

/* 
 *  This procedure decodes the X.25 level 3 packet returning a 
 *  code to be used in switchs or arrays.
 */

pk_decode (xp)
register struct x25_packet *xp;
{
	register int type;

	if (X25GBITS(xp -> bits, fmt_identifier) != 1)
		return (INVALID_PACKET);
#ifdef ancient_history
	/* 
	 *  Make sure that the logical channel group number is 0.
	 *  This restriction may be removed at some later date.
	 */
	if (xp -> lc_group_number != 0)
		return (INVALID_PACKET);
#endif
	/* 
	 *  Test for data packet first.
	 */
	if (!(xp -> packet_type & DATA_PACKET_DESIGNATOR))
		return (DATA);

	/* 
	 *  Test if flow control packet (RR or RNR).
	 */
	if (!(xp -> packet_type & RR_OR_RNR_PACKET_DESIGNATOR))
		switch (xp -> packet_type & 0x1f) {
		case X25_RR:
			return (RR);
		case X25_RNR:
			return (RNR);
		case X25_REJECT:
			return (REJECT);
		}

	/* 
	 *  Determine the rest of the packet types.
	 */
	switch (xp -> packet_type) {
	case X25_CALL: 
		type = CALL;
		break;

	case X25_CALL_ACCEPTED: 
		type = CALL_ACCEPTED;
		break;

	case X25_CLEAR: 
		type = CLEAR;
		break;

	case X25_CLEAR_CONFIRM: 
		type = CLEAR_CONF;
		break;

	case X25_INTERRUPT: 
		type = INTERRUPT;
		break;

	case X25_INTERRUPT_CONFIRM: 
		type = INTERRUPT_CONF;
		break;

	case X25_RESET: 
		type = RESET;
		break;

	case X25_RESET_CONFIRM: 
		type = RESET_CONF;
		break;

	case X25_RESTART: 
		type = RESTART;
		break;

	case X25_RESTART_CONFIRM: 
		type = RESTART_CONF;
		break;

	case X25_DIAGNOSTIC:
		type = DIAG_TYPE;
		break;

	default: 
		type = INVALID_PACKET;
	}
	return (type);
}

/* 
 *  A restart packet has been received. Print out the reason
 *  for the restart.
 */

pk_restartcause (pkp, xp)
struct pkcb *pkp;
register struct x25_packet *xp;
{
	register struct x25config *xcp = pkp -> pk_xcp;
	register int lcn = LCN(xp);

	switch (xp -> packet_data) {
	case X25_RESTART_LOCAL_PROCEDURE_ERROR: 
		pk_message (lcn, xcp, "restart: local procedure error");
		break;

	case X25_RESTART_NETWORK_CONGESTION: 
		pk_message (lcn, xcp, "restart: network congestion");
		break;

	case X25_RESTART_NETWORK_OPERATIONAL: 
		pk_message (lcn, xcp, "restart: network operational");
		break;

	default: 
		pk_message (lcn, xcp, "restart: unknown cause");
	}
}

#define MAXRESETCAUSE	7

int     Reset_cause[] = {
	EXRESET, EXROUT, 0, EXRRPE, 0, EXRLPE, 0, EXRNCG
};

/* 
 *  A reset packet has arrived. Return the cause to the user.
 */

pk_resetcause (pkp, xp)
struct pkcb *pkp;
register struct x25_packet *xp;
{
	register struct pklcd *lcp =
				pkp -> pk_chan[LCN(xp)];
	register int code = xp -> packet_data;

	if (code > MAXRESETCAUSE)
		code = 7;	/* EXRNCG */

	pk_message (LCN(xp), lcp -> lcd_pkp, "reset code 0x%x, diagnostic 0x%x",
			xp -> packet_data, 4[(u_char *)xp]);
			
	if (lcp -> lcd_so)
		lcp -> lcd_so -> so_error = Reset_cause[code];
}

#define MAXCLEARCAUSE	25

int     Clear_cause[] = {
	EXCLEAR, EXCBUSY, 0, EXCINV, 0, EXCNCG, 0,
	0, 0, EXCOUT, 0, EXCAB, 0, EXCNOB, 0, 0, 0, EXCRPE,
	0, EXCLPE, 0, 0, 0, 0, 0, EXCRRC
};

/* 
 *  A clear packet has arrived. Return the cause to the user.
 */

pk_clearcause (pkp, xp)
struct pkcb *pkp;
register struct x25_packet *xp;
{
	register struct pklcd *lcp =
		pkp -> pk_chan[LCN(xp)];
	register int code = xp -> packet_data;

	if (code > MAXCLEARCAUSE)
		code = 5;	/* EXRNCG */
	if (lcp -> lcd_so)
		lcp -> lcd_so -> so_error = Clear_cause[code];
}

char *
format_ntn (xcp)
register struct x25config *xcp;
{

	return (xcp -> xc_addr.x25_addr);
}

/* VARARGS1 */
pk_message (lcn, xcp, fmt, a1, a2, a3, a4, a5, a6)
struct x25config *xcp;
char *fmt;
{

	if (lcn)
		if (!PQEMPTY)
			printf ("X.25(%s): lcn %d: ", format_ntn (xcp), lcn);
		else
			printf ("X.25: lcn %d: ", lcn);
	else
		if (!PQEMPTY)
			printf ("X.25(%s): ", format_ntn (xcp));
		else
			printf ("X.25: ");

	printf (fmt, a1, a2, a3, a4, a5, a6);
	printf ("\n");
}

pk_fragment (lcp, m0, qbit, mbit, wait)
struct mbuf *m0;
register struct pklcd *lcp;
{
	register struct mbuf *m = m0;
	register struct x25_packet *xp;
	register struct sockbuf *sb;
	struct mbuf *head = 0, *next, **mp = &head, *m_split ();
	int totlen, psize = 1 << (lcp -> lcd_packetsize);

	if (m == 0)
		return 0;
	if (m -> m_flags & M_PKTHDR == 0)
		panic ("pk_fragment");
	totlen = m -> m_pkthdr.len;
	m -> m_act = 0;
	sb = lcp -> lcd_so ? &lcp -> lcd_so -> so_snd : & lcp -> lcd_sb;
	do {
		if (totlen > psize) {
			if ((next = m_split (m, psize, wait)) == 0)
				goto abort;
			totlen -= psize;
		} else
			next = 0;
		M_PREPEND(m, PKHEADERLN, wait);
		if (m == 0)
			goto abort;
		*mp = m;
		mp = & m -> m_act;
		*mp = 0;
		xp = mtod (m, struct x25_packet *);
		0[(char *)xp] = 0;
		if (qbit)
			X25SBITS(xp -> bits, q_bit, 1);
		if (lcp -> lcd_flags & X25_DBIT)
			X25SBITS(xp -> bits, d_bit, 1);
		X25SBITS(xp -> bits, fmt_identifier, 1);
		xp -> packet_type = X25_DATA;
		SET_LCN(xp, lcp -> lcd_lcn);
		if (next || (mbit && (totlen == psize ||
				      (lcp -> lcd_flags & X25_DBIT))))
			SMBIT(xp, 1);
	} while (m = next);
	for (m = head; m; m = next) {
		next = m -> m_act;
		m -> m_act = 0;
		sbappendrecord (sb, m);
	}
	return 0;
abort:
	if (wait)
		panic ("pk_fragment null mbuf after wait");
	if (next)
		m_freem (next);
	for (m = head; m; m = next) {
		next = m -> m_act;
		m_freem (m);
	}
	return ENOBUFS;
}