671 lines
17 KiB
C
671 lines
17 KiB
C
/*
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* Copyright (c) University of British Columbia, 1984
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* the Laboratory for Computation Vision and the Computer Science Department
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* of the University of British Columbia.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)hd_input.c 8.1 (Berkeley) 6/10/93
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* $Id$
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/domain.h>
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#include <sys/socket.h>
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#include <sys/protosw.h>
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#include <sys/errno.h>
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#include <sys/time.h>
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#include <sys/kernel.h>
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#include <net/if.h>
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#include <netccitt/hdlc.h>
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#include <netccitt/hd_var.h>
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#include <netccitt/x25.h>
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static frame_reject();
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static rej_routine();
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static free_iframes();
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/*
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* HDLC INPUT INTERFACE
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*
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* This routine is called when the HDLC physical device has
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* completed reading a frame.
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*/
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hdintr ()
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{
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register struct mbuf *m;
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register struct hdcb *hdp;
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register struct ifnet *ifp;
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register int s;
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static struct ifnet *lastifp;
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static struct hdcb *lasthdp;
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for (;;) {
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s = splimp ();
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IF_DEQUEUE (&hdintrq, m);
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splx (s);
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if (m == 0)
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break;
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if (m->m_len < HDHEADERLN) {
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printf ("hdintr: packet too short (len=%d)\n",
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m->m_len);
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m_freem (m);
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continue;
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}
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if ((m->m_flags & M_PKTHDR) == 0)
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panic("hdintr");
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ifp = m->m_pkthdr.rcvif;
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/*
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* look up the appropriate hdlc control block
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*/
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if (ifp == lastifp)
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hdp = lasthdp;
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else {
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for (hdp = hdcbhead; hdp; hdp = hdp->hd_next)
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if (hdp->hd_ifp == ifp)
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break;
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if (hdp == 0) {
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printf ("hdintr: unknown interface %x\n", ifp);
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m_freem (m);
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continue;
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}
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lastifp = ifp;
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lasthdp = hdp;
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}
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/* Process_rxframe returns FALSE if the frame was NOT queued
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for the next higher layers. */
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if (process_rxframe (hdp, m) == FALSE)
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m_freem (m);
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}
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}
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process_rxframe (hdp, fbuf)
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register struct hdcb *hdp;
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register struct mbuf *fbuf;
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{
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register int queued = FALSE, frametype, pf;
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register struct Hdlc_frame *frame;
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frame = mtod (fbuf, struct Hdlc_frame *);
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pf = ((struct Hdlc_iframe *) frame) -> pf;
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hd_trace (hdp, RX, frame);
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if (frame -> address != ADDRESS_A && frame -> address != ADDRESS_B)
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return (queued);
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switch ((frametype = hd_decode (hdp, frame)) + hdp->hd_state) {
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case DM + DISC_SENT:
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case UA + DISC_SENT:
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/*
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* Link now closed. Leave timer running
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* so hd_timer() can periodically check the
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* status of interface driver flag bit IFF_UP.
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*/
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hdp->hd_state = DISCONNECTED;
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break;
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case DM + INIT:
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case UA + INIT:
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/*
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* This is a non-standard state change needed for DCEs
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* that do dynamic link selection. We can't go into the
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* usual "SEND DM" state because a DM is a SARM in LAP.
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*/
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hd_writeinternal (hdp, SABM, POLLOFF);
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hdp->hd_state = SABM_SENT;
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SET_TIMER (hdp);
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break;
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case SABM + DM_SENT:
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case SABM + WAIT_SABM:
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hd_writeinternal (hdp, UA, pf);
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case UA + SABM_SENT:
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case UA + WAIT_UA:
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KILL_TIMER (hdp);
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hd_initvars (hdp);
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hdp->hd_state = ABM;
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hd_message (hdp, "Link level operational");
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/* Notify the packet level - to send RESTART. */
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(void) pk_ctlinput (PRC_LINKUP, hdp->hd_pkp);
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break;
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case SABM + SABM_SENT:
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/* Got a SABM collision. Acknowledge the remote's SABM
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via UA but still wait for UA. */
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hd_writeinternal (hdp, UA, pf);
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break;
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case SABM + ABM:
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/* Request to reset the link from the remote. */
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KILL_TIMER (hdp);
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hd_message (hdp, "Link reset");
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#ifdef HDLCDEBUG
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hd_dumptrace (hdp);
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#endif
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hd_flush (hdp->hd_ifp);
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hd_writeinternal (hdp, UA, pf);
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hd_initvars (hdp);
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(void) pk_ctlinput (PRC_LINKRESET, hdp->hd_pkp);
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hdp->hd_resets++;
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break;
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case SABM + WAIT_UA:
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hd_writeinternal (hdp, UA, pf);
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break;
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case DM + ABM:
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hd_message (hdp, "DM received: link down");
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#ifdef HDLCDEBUG
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hd_dumptrace (hdp);
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#endif
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(void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_pkp);
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hd_flush (hdp->hd_ifp);
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case DM + DM_SENT:
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case DM + WAIT_SABM:
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case DM + WAIT_UA:
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hd_writeinternal (hdp, SABM, pf);
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hdp->hd_state = SABM_SENT;
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SET_TIMER (hdp);
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break;
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case DISC + INIT:
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case DISC + DM_SENT:
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case DISC + SABM_SENT:
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/* Note: This is a non-standard state change. */
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hd_writeinternal (hdp, UA, pf);
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hd_writeinternal (hdp, SABM, POLLOFF);
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hdp->hd_state = SABM_SENT;
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SET_TIMER (hdp);
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break;
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case DISC + WAIT_UA:
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hd_writeinternal (hdp, DM, pf);
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SET_TIMER (hdp);
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hdp->hd_state = DM_SENT;
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break;
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case DISC + ABM:
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hd_message (hdp, "DISC received: link down");
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(void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_pkp);
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case DISC + WAIT_SABM:
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hd_writeinternal (hdp, UA, pf);
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hdp->hd_state = DM_SENT;
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SET_TIMER (hdp);
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break;
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case UA + ABM:
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hd_message (hdp, "UA received: link down");
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(void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_pkp);
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case UA + WAIT_SABM:
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hd_writeinternal (hdp, DM, pf);
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hdp->hd_state = DM_SENT;
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SET_TIMER (hdp);
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break;
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case FRMR + DM_SENT:
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hd_writeinternal (hdp, SABM, pf);
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hdp->hd_state = SABM_SENT;
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SET_TIMER (hdp);
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break;
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case FRMR + WAIT_SABM:
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hd_writeinternal (hdp, DM, pf);
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hdp->hd_state = DM_SENT;
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SET_TIMER (hdp);
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break;
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case FRMR + ABM:
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hd_message (hdp, "FRMR received: link down");
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(void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_pkp);
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#ifdef HDLCDEBUG
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hd_dumptrace (hdp);
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#endif
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hd_flush (hdp->hd_ifp);
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hd_writeinternal (hdp, SABM, pf);
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hdp->hd_state = WAIT_UA;
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SET_TIMER (hdp);
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break;
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case RR + ABM:
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case RNR + ABM:
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case REJ + ABM:
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process_sframe (hdp, (struct Hdlc_sframe *)frame, frametype);
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break;
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case IFRAME + ABM:
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queued = process_iframe (hdp, fbuf, (struct Hdlc_iframe *)frame);
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break;
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case IFRAME + SABM_SENT:
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case RR + SABM_SENT:
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case RNR + SABM_SENT:
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case REJ + SABM_SENT:
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hd_writeinternal (hdp, DM, POLLON);
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hdp->hd_state = DM_SENT;
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SET_TIMER (hdp);
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break;
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case IFRAME + WAIT_SABM:
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case RR + WAIT_SABM:
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case RNR + WAIT_SABM:
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case REJ + WAIT_SABM:
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hd_writeinternal (hdp, FRMR, POLLOFF);
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SET_TIMER (hdp);
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break;
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case ILLEGAL + SABM_SENT:
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hdp->hd_unknown++;
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hd_writeinternal (hdp, DM, POLLOFF);
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hdp->hd_state = DM_SENT;
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SET_TIMER (hdp);
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break;
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case ILLEGAL + ABM:
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hd_message (hdp, "Unknown frame received: link down");
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(void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_pkp);
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case ILLEGAL + WAIT_SABM:
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hdp->hd_unknown++;
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#ifdef HDLCDEBUG
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hd_dumptrace (hdp);
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#endif
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hd_writeinternal (hdp, FRMR, POLLOFF);
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hdp->hd_state = WAIT_SABM;
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SET_TIMER (hdp);
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break;
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}
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return (queued);
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}
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process_iframe (hdp, fbuf, frame)
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register struct hdcb *hdp;
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struct mbuf *fbuf;
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register struct Hdlc_iframe *frame;
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{
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register int nr = frame -> nr,
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ns = frame -> ns,
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pf = frame -> pf;
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register int queued = FALSE;
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/*
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* Validate the iframe's N(R) value. It's N(R) value must be in
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* sync with our V(S) value and our "last received nr".
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*/
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if (valid_nr (hdp, nr, FALSE) == FALSE) {
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frame_reject (hdp, Z, frame);
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return (queued);
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}
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/*
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* This section tests the IFRAME for proper sequence. That is, it's
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* sequence number N(S) MUST be equal to V(S).
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*/
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if (ns != hdp->hd_vr) {
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hdp->hd_invalid_ns++;
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if (pf || (hdp->hd_condition & REJ_CONDITION) == 0) {
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hdp->hd_condition |= REJ_CONDITION;
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/*
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* Flush the transmit queue. This is ugly but we
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* have no choice. A reject response must be
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* immediately sent to the DCE. Failure to do so
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* may result in another out of sequence iframe
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* arriving (and thus sending another reject)
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* before the first reject is transmitted. This
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* will cause the DCE to receive two or more
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* rejects back to back, which must never happen.
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*/
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hd_flush (hdp->hd_ifp);
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hd_writeinternal (hdp, REJ, pf);
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}
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return (queued);
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}
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hdp->hd_condition &= ~REJ_CONDITION;
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/*
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* This section finally tests the IFRAME's sequence number against
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* the window size (K) and the sequence number of the last frame
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* we have acknowledged. If the IFRAME is completely correct then
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* it is queued for the packet level.
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*/
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if (ns != (hdp -> hd_lasttxnr + hdp -> hd_xcp -> xc_lwsize) % MODULUS) {
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hdp -> hd_vr = (hdp -> hd_vr + 1) % MODULUS;
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if (pf == 1) {
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/* Must generate a RR or RNR with final bit on. */
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hd_writeinternal (hdp, RR, POLLON);
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} else
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/*
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* Hopefully we can piggyback the RR, if not we will generate
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* a RR when T3 timer expires.
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*/
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if (hdp -> hd_rrtimer == 0)
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hdp->hd_rrtimer = hd_t3;
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/* Forward iframe to packet level of X.25. */
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fbuf -> m_data += HDHEADERLN;
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fbuf -> m_len -= HDHEADERLN;
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fbuf -> m_pkthdr.len -= HDHEADERLN;
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fbuf -> m_pkthdr.rcvif = (struct ifnet *)hdp -> hd_pkp;
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#ifdef BSD4_3
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fbuf->m_act = 0; /* probably not necessary */
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#else
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{
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register struct mbuf *m;
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for (m = fbuf; m -> m_next; m = m -> m_next)
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m -> m_act = (struct mbuf *) 0;
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m -> m_act = (struct mbuf *) 1;
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}
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#endif
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pk_input (fbuf);
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queued = TRUE;
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hd_start (hdp);
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} else {
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/*
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* Here if the remote station has transmitted more iframes then
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* the number which have been acknowledged plus K.
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*/
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hdp->hd_invalid_ns++;
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frame_reject (hdp, W, frame);
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}
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return (queued);
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}
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/*
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* This routine is used to determine if a value (the middle parameter)
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* is between two other values. The low value is the first parameter
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* the high value is the last parameter. The routine checks the middle
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* value to see if it is within the range of the first and last values.
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* The reason we need this routine is the values are modulo some base
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* hence a simple test for greater or less than is not sufficient.
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*/
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bool
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range_check (rear, value, front)
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int rear,
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value,
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front;
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{
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register bool result = FALSE;
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if (front > rear)
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result = (rear <= value) && (value <= front);
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else
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result = (rear <= value) || (value <= front);
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return (result);
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}
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/*
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* This routine handles all the frame reject conditions which can
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* arise as a result of secondary processing. The frame reject
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* condition Y (frame length error) are handled elsewhere.
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*/
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static
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frame_reject (hdp, rejectcode, frame)
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struct hdcb *hdp;
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struct Hdlc_iframe *frame;
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{
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register struct Frmr_frame *frmr = &hd_frmr;
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frmr -> frmr_control = ((struct Hdlc_frame *) frame) -> control;
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frmr -> frmr_ns = frame -> ns;
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frmr -> frmr_f1_0 = 0;
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frmr -> frmr_nr = frame -> nr;
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frmr -> frmr_f2_0 = 0;
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frmr -> frmr_0000 = 0;
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frmr -> frmr_w = frmr -> frmr_x = frmr -> frmr_y =
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frmr -> frmr_z = 0;
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switch (rejectcode) {
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case Z:
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frmr -> frmr_z = 1;/* invalid N(R). */
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break;
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case Y:
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frmr -> frmr_y = 1;/* iframe length error. */
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break;
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case X:
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frmr -> frmr_x = 1;/* invalid information field. */
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frmr -> frmr_w = 1;
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break;
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case W:
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frmr -> frmr_w = 1;/* invalid N(S). */
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}
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hd_writeinternal (hdp, FRMR, POLLOFF);
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hdp->hd_state = WAIT_SABM;
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SET_TIMER (hdp);
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}
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/*
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* This procedure is invoked when ever we receive a supervisor
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* frame such as RR, RNR and REJ. All processing for these
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* frames is done here.
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*/
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process_sframe (hdp, frame, frametype)
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register struct hdcb *hdp;
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register struct Hdlc_sframe *frame;
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int frametype;
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{
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register int nr = frame -> nr, pf = frame -> pf, pollbit = 0;
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if (valid_nr (hdp, nr, pf) == TRUE) {
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switch (frametype) {
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case RR:
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hdp->hd_condition &= ~REMOTE_RNR_CONDITION;
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break;
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case RNR:
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hdp->hd_condition |= REMOTE_RNR_CONDITION;
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hdp->hd_retxcnt = 0;
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break;
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case REJ:
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hdp->hd_condition &= ~REMOTE_RNR_CONDITION;
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rej_routine (hdp, nr);
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}
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if (pf == 1) {
|
|
hdp->hd_retxcnt = 0;
|
|
hdp->hd_condition &= ~TIMER_RECOVERY_CONDITION;
|
|
|
|
if (frametype == RR && hdp->hd_lastrxnr == hdp->hd_vs
|
|
&& hdp->hd_timer == 0 && hdp->hd_txq.head == 0)
|
|
hd_writeinternal(hdp, RR, pf);
|
|
else
|
|
/* If any iframes have been queued because of the
|
|
timer condition, transmit then now. */
|
|
if (hdp->hd_condition & REMOTE_RNR_CONDITION) {
|
|
/* Remote is busy or timer condition, so only
|
|
send one. */
|
|
if (hdp->hd_vs != hdp->hd_retxqi)
|
|
hd_send_iframe (hdp, hdp->hd_retxq[hdp->hd_vs], pollbit);
|
|
}
|
|
else /* Flush the retransmit list first. */
|
|
while (hdp->hd_vs != hdp->hd_retxqi)
|
|
hd_send_iframe (hdp, hdp->hd_retxq[hdp->hd_vs], POLLOFF);
|
|
}
|
|
|
|
hd_start (hdp);
|
|
} else
|
|
frame_reject (hdp, Z, (struct Hdlc_iframe *)frame); /* Invalid N(R). */
|
|
}
|
|
|
|
/*
|
|
* This routine tests the validity of the N(R) which we have received.
|
|
* If it is ok, then all the iframes which it acknowledges (if any)
|
|
* will be freed.
|
|
*/
|
|
|
|
bool
|
|
valid_nr (hdp, nr, finalbit)
|
|
register struct hdcb *hdp;
|
|
register int finalbit;
|
|
{
|
|
/* Make sure it really does acknowledge something. */
|
|
if (hdp->hd_lastrxnr == nr)
|
|
return (TRUE);
|
|
|
|
/*
|
|
* This section validates the frame's N(R) value. It's N(R) value
|
|
* must be in syncronization with our V(S) value and our "last
|
|
* received nr" variable. If it is correct then we are able to send
|
|
* more IFRAME's, else frame reject condition is entered.
|
|
*/
|
|
|
|
if (range_check (hdp->hd_lastrxnr, nr, hdp->hd_vs) == FALSE) {
|
|
if ((hdp->hd_condition & TIMER_RECOVERY_CONDITION) &&
|
|
range_check (hdp->hd_vs, nr, hdp->hd_xx) == TRUE)
|
|
hdp->hd_vs = nr;
|
|
|
|
else {
|
|
hdp->hd_invalid_nr++;
|
|
return (FALSE);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we get to here, we do have a valid frame but it might be out
|
|
* of sequence. However, we should still accept the receive state
|
|
* number N(R) since it has already passed our previous test and it
|
|
* does acknowledge frames which we are sending.
|
|
*/
|
|
|
|
KILL_TIMER (hdp);
|
|
free_iframes (hdp, &nr, finalbit);/* Free all acknowledged iframes */
|
|
if (nr != hdp->hd_vs)
|
|
SET_TIMER (hdp);
|
|
|
|
return (TRUE);
|
|
}
|
|
|
|
/*
|
|
* This routine determines how many iframes need to be retransmitted.
|
|
* It then resets the Send State Variable V(S) to accomplish this.
|
|
*/
|
|
|
|
static
|
|
rej_routine (hdp, rejnr)
|
|
register struct hdcb *hdp;
|
|
register int rejnr;
|
|
{
|
|
register int anchor;
|
|
|
|
/*
|
|
* Flush the output queue. Any iframes queued for
|
|
* transmission will be out of sequence.
|
|
*/
|
|
|
|
hd_flush (hdp->hd_ifp);
|
|
|
|
/*
|
|
* Determine how many frames should be re-transmitted. In the case
|
|
* of a normal REJ this should be 1 to K. In the case of a timer
|
|
* recovery REJ (ie. a REJ with the Final Bit on) this could be 0.
|
|
*/
|
|
|
|
anchor = hdp->hd_vs;
|
|
if (hdp->hd_condition & TIMER_RECOVERY_CONDITION)
|
|
anchor = hdp->hd_xx;
|
|
|
|
anchor = (anchor - rejnr + 8) % MODULUS;
|
|
|
|
if (anchor > 0) {
|
|
|
|
/* There is at least one iframe to retransmit. */
|
|
KILL_TIMER (hdp);
|
|
hdp->hd_vs = rejnr;
|
|
|
|
while (hdp->hd_vs != hdp->hd_retxqi)
|
|
hd_send_iframe (hdp, hdp->hd_retxq[hdp->hd_vs], POLLOFF);
|
|
|
|
}
|
|
hd_start (hdp);
|
|
}
|
|
|
|
/*
|
|
* This routine frees iframes from the retransmit queue. It is called
|
|
* when a previously written iframe is acknowledged.
|
|
*/
|
|
|
|
static
|
|
free_iframes (hdp, nr, finalbit)
|
|
register struct hdcb *hdp;
|
|
int *nr;
|
|
register int finalbit;
|
|
|
|
{
|
|
register int i, k;
|
|
|
|
/*
|
|
* We need to do the following because of a funny quirk in the
|
|
* protocol. This case occures when in Timer recovery condition
|
|
* we get a N(R) which acknowledges all the outstanding iframes
|
|
* but with the Final Bit off. In this case we need to save the last
|
|
* iframe for possible retransmission even though it has already been
|
|
* acknowledged!
|
|
*/
|
|
|
|
if ((hdp->hd_condition & TIMER_RECOVERY_CONDITION) && *nr == hdp->hd_xx && finalbit == 0) {
|
|
*nr = (*nr - 1 + 8) % MODULUS;
|
|
/* printf ("QUIRK\n"); */
|
|
}
|
|
|
|
k = (*nr - hdp->hd_lastrxnr + 8) % MODULUS;
|
|
|
|
/* Loop here freeing all acknowledged iframes. */
|
|
for (i = 0; i < k; ++i) {
|
|
m_freem (hdp->hd_retxq[hdp->hd_lastrxnr]);
|
|
hdp->hd_retxq[hdp->hd_lastrxnr] = 0;
|
|
hdp->hd_lastrxnr = (hdp->hd_lastrxnr + 1) % MODULUS;
|
|
}
|
|
|
|
}
|