248 lines
6.9 KiB
C
248 lines
6.9 KiB
C
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/*
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* Copyright (c) University of British Columbia, 1984
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* Copyright (c) 1990 The Regents of the University of California.
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* 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_output.c 7.6 (Berkeley) 5/29/91
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*/
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#include "param.h"
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#include "systm.h"
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#include "mbuf.h"
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#include "domain.h"
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#include "socket.h"
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#include "syslog.h"
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#include "protosw.h"
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#include "errno.h"
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#include "time.h"
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#include "kernel.h"
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#include "../net/if.h"
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#include "hdlc.h"
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#include "hd_var.h"
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#include "x25.h"
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/*
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* HDLC OUTPUT INTERFACE
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*
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* This routine is called when the X.25 packet layer output routine
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* has a information frame (iframe) to write. It is also called
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* by the input and control routines of the HDLC layer.
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*/
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hd_output (hdp, m0)
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register struct hdcb *hdp;
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struct mbuf *m0;
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{
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struct x25config *xcp;
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register struct mbuf *m = m0;
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int len;
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if (m == NULL)
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panic ("hd_output");
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if (m->m_flags & M_PKTHDR == 0)
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panic ("hd_output 2");
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if (hdp->hd_state != ABM) {
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m_freem (m);
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return;
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}
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/*
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* Make room for the hdlc header either by prepending
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* another mbuf, or by adjusting the offset and length
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* of the first mbuf in the mbuf chain.
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*/
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M_PREPEND(m, HDHEADERLN, M_DONTWAIT);
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if (m == NULL)
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return;
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for (len = 0; m; m = m->m_next)
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len += m->m_len;
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m = m0;
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m->m_pkthdr.len = len;
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hd_append (&hdp->hd_txq, m);
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hd_start (hdp);
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}
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hd_start (hdp)
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register struct hdcb *hdp;
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{
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register struct mbuf *m;
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/*
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* The iframe is only transmitted if all these conditions are FALSE.
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* The iframe remains queued (hdp->hd_txq) however and will be
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* transmitted as soon as these conditions are cleared.
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*/
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while (!(hdp->hd_condition & (TIMER_RECOVERY_CONDITION | REMOTE_RNR_CONDITION | REJ_CONDITION))) {
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if (hdp->hd_vs == (hdp->hd_lastrxnr + hdp->hd_xcp->xc_lwsize) % MODULUS) {
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/* We have now exceeded the maximum number of
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outstanding iframes. Therefore, we must wait
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until at least one is acknowledged if this
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condition is not turned off before we are
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requested to write another iframe. */
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hdp->hd_window_condition++;
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break;
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}
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/* hd_remove top iframe from transmit queue. */
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if ((m = hd_remove (&hdp->hd_txq)) == NULL)
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break;
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hd_send_iframe (hdp, m, POLLOFF);
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}
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}
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/*
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* This procedure is passed a buffer descriptor for an iframe. It builds
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* the rest of the control part of the frame and then writes it out. It
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* also starts the acknowledgement timer and keeps the iframe in the
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* Retransmit queue (Retxq) just in case we have to do this again.
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*
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* Note: This routine is also called from hd_input.c when retransmission
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* of old frames is required.
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*/
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hd_send_iframe (hdp, buf, poll_bit)
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register struct hdcb *hdp;
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register struct mbuf *buf;
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int poll_bit;
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{
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register struct Hdlc_iframe *iframe;
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struct mbuf *m;
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KILL_TIMER (hdp);
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if (buf == 0) {
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printf ("hd_send_iframe: zero arg\n");
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#ifdef HDLCDEBUG
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hd_status (hdp);
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hd_dumptrace (hdp);
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#endif
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hdp->hd_vs = (hdp->hd_vs + 7) % MODULUS;
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return;
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}
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iframe = mtod (buf, struct Hdlc_iframe *);
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iframe -> hdlc_0 = 0;
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iframe -> nr = hdp->hd_vr;
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iframe -> pf = poll_bit;
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iframe -> ns = hdp->hd_vs;
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iframe -> address = ADDRESS_B;
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hdp->hd_lasttxnr = hdp->hd_vr;
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hdp->hd_rrtimer = 0;
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if (hdp->hd_vs == hdp->hd_retxqi) {
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/* Check for retransmissions. */
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/* Put iframe only once in the Retransmission queue. */
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hdp->hd_retxq[hdp->hd_retxqi] = buf;
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hdp->hd_retxqi = (hdp->hd_retxqi + 1) % MODULUS;
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hdp->hd_iframes_out++;
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}
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hdp->hd_vs = (hdp->hd_vs + 1) % MODULUS;
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hd_trace (hdp, TX, (struct Hdlc_frame *)iframe);
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/* Write buffer on device. */
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m = hdp->hd_dontcopy ? buf : m_copy(buf, 0, (int)M_COPYALL);
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if (m == 0) {
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printf("hdlc: out of mbufs\n");
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return;
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}
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(*hdp->hd_output)(hdp, m);
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SET_TIMER (hdp);
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}
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hd_ifoutput(hdp, m)
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register struct mbuf *m;
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register struct hdcb *hdp;
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{
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/*
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* Queue message on interface, and start output if interface
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* not yet active.
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*/
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register struct ifnet *ifp = hdp->hd_ifp;
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int s = splimp();
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if (IF_QFULL(&ifp->if_snd)) {
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IF_DROP(&ifp->if_snd);
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/* printf("%s%d: HDLC says OK to send but queue full, may hang\n",
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ifp->if_name, ifp->if_unit);*/
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m_freem(m);
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} else {
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IF_ENQUEUE(&ifp->if_snd, m);
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if ((ifp->if_flags & IFF_OACTIVE) == 0)
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(*ifp->if_start)(ifp);
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}
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splx(s);
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}
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/*
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* This routine gets control when the timer expires because we have not
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* received an acknowledgement for a iframe.
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*/
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hd_resend_iframe (hdp)
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register struct hdcb *hdp;
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{
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if (hdp->hd_retxcnt++ < hd_n2) {
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if (!(hdp->hd_condition & TIMER_RECOVERY_CONDITION)) {
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hdp->hd_xx = hdp->hd_vs;
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hdp->hd_condition |= TIMER_RECOVERY_CONDITION;
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}
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hdp->hd_vs = hdp->hd_lastrxnr;
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hd_send_iframe (hdp, hdp->hd_retxq[hdp->hd_vs], POLLON);
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} else {
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/* At this point we have not received a RR even after N2
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retries - attempt to reset link. */
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hd_initvars (hdp);
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hd_writeinternal (hdp, SABM, POLLOFF);
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hdp->hd_state = WAIT_UA;
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SET_TIMER (hdp);
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hd_message (hdp, "Timer recovery failed: link down");
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(void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_pkp);
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}
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}
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