bsd/netccitt/hd_output.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) University of British Columbia, 1984
  24  * Copyright (c) 1990, 1993
  25  *      The Regents of the University of California.  All rights reserved.
  26  *
  27  * This code is derived from software contributed to Berkeley by
  28  * the Laboratory for Computation Vision and the Computer Science Department
  29  * of the University of British Columbia.
  30  *
  31  * Redistribution and use in source and binary forms, with or without
  32  * modification, are permitted provided that the following conditions
  33  * are met:
  34  * 1. Redistributions of source code must retain the above copyright
  35  *    notice, this list of conditions and the following disclaimer.
  36  * 2. Redistributions in binary form must reproduce the above copyright
  37  *    notice, this list of conditions and the following disclaimer in the
  38  *    documentation and/or other materials provided with the distribution.
  39  * 3. All advertising materials mentioning features or use of this software
  40  *    must display the following acknowledgement:
  41  *      This product includes software developed by the University of
  42  *      California, Berkeley and its contributors.
  43  * 4. Neither the name of the University nor the names of its contributors
  44  *    may be used to endorse or promote products derived from this software
  45  *    without specific prior written permission.
  46  *
  47  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  48  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  50  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  51  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  52  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  53  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  54  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  55  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  57  * SUCH DAMAGE.
  58  *
  59  *      @(#)hd_output.c 8.1 (Berkeley) 6/10/93
  60  */
  61
  62 #include <sys/param.h>
  63 #include <sys/systm.h>
  64 #include <sys/mbuf.h>
  65 #include <sys/domain.h>
  66 #include <sys/socket.h>
  67 #include <sys/syslog.h>
  68 #include <sys/protosw.h>
  69 #include <sys/errno.h>
  70 #include <sys/time.h>
  71 #include <sys/kernel.h>
  72
  73 #include <net/if.h>
  74
  75 #include <netccitt/hdlc.h>
  76 #include <netccitt/hd_var.h>
  77 #include <netccitt/x25.h>
  78
  79 /*
  80  *      HDLC OUTPUT INTERFACE
  81  *
  82  *      This routine is called when the X.25 packet layer output routine
  83  *      has a information frame (iframe)  to write.   It is  also called
  84  *      by the input and control routines of the HDLC layer.
  85  */
  86
  87 hd_output (hdp, m0)
  88 register struct hdcb *hdp;
  89 struct mbuf *m0;
  90 {
  91         struct x25config *xcp;
  92         register struct mbuf *m = m0;
  93         int len;
  94
  95         if (m == NULL)
  96                 panic ("hd_output");
  97         if ((m->m_flags & M_PKTHDR) == 0)
  98                 panic ("hd_output 2");
  99
 100         if (hdp->hd_state != ABM) {
 101                 m_freem (m);
 102                 return;
 103         }
 104
 105         /*
 106          * Make room for the hdlc header either by prepending
 107          * another mbuf, or by adjusting the offset and length
 108          * of the first mbuf in the mbuf chain.
 109          */
 110
 111         M_PREPEND(m, HDHEADERLN, M_DONTWAIT);
 112         if (m == NULL)
 113                 return;
 114         for (len = 0; m; m = m->m_next)
 115                 len += m->m_len;
 116         m = m0;
 117         m->m_pkthdr.len = len;
 118
 119         hd_append (&hdp->hd_txq, m);
 120         hd_start (hdp);
 121 }
 122
 123 hd_start (hdp)
 124 register struct hdcb *hdp;
 125 {
 126         register struct mbuf *m;
 127
 128         /*
 129          * The iframe is only transmitted if all these conditions are FALSE.
 130          * The iframe remains queued (hdp->hd_txq) however and will be
 131          * transmitted as soon as these conditions are cleared.
 132          */
 133
 134         while (!(hdp->hd_condition & (TIMER_RECOVERY_CONDITION | REMOTE_RNR_CONDITION | REJ_CONDITION))) {
 135                 if (hdp->hd_vs == (hdp->hd_lastrxnr + hdp->hd_xcp->xc_lwsize) % MODULUS) {
 136
 137                         /* We have now exceeded the  maximum  number  of
 138                            outstanding iframes. Therefore,  we must wait
 139                            until  at least  one is acknowledged if this
 140                            condition  is not  turned off before we are
 141                            requested to write another iframe. */
 142                         hdp->hd_window_condition++;
 143                         break;
 144                 }
 145
 146                 /* hd_remove top iframe from transmit queue. */
 147                 if ((m = hd_remove (&hdp->hd_txq)) == NULL)
 148                         break;
 149
 150                 hd_send_iframe (hdp, m, POLLOFF);
 151         }
 152 }
 153
 154 /*
 155  *  This procedure is passed a buffer descriptor for an iframe. It builds
 156  *  the rest of the control part of the frame and then writes it out.  It
 157  *  also  starts the  acknowledgement  timer and keeps  the iframe in the
 158  *  Retransmit queue (Retxq) just in case  we have to do this again.
 159  *
 160  *  Note: This routine is also called from hd_input.c when retransmission
 161  *       of old frames is required.
 162  */
 163
 164 hd_send_iframe (hdp, buf, poll_bit)
 165 register struct hdcb *hdp;
 166 register struct mbuf *buf;
 167 int poll_bit;
 168 {
 169         register struct Hdlc_iframe *iframe;
 170         struct mbuf *m;
 171
 172         KILL_TIMER (hdp);
 173
 174         if (buf == 0) {
 175                 printf ("hd_send_iframe: zero arg\n");
 176 #ifdef HDLCDEBUG
 177                 hd_status (hdp);
 178                 hd_dumptrace (hdp);
 179 #endif
 180                 hdp->hd_vs = (hdp->hd_vs + 7) % MODULUS;
 181                 return;
 182         }
 183         iframe = mtod (buf, struct Hdlc_iframe *);
 184
 185         iframe -> hdlc_0 = 0;
 186         iframe -> nr = hdp->hd_vr;
 187         iframe -> pf = poll_bit;
 188         iframe -> ns = hdp->hd_vs;
 189         iframe -> address = ADDRESS_B;
 190         hdp->hd_lasttxnr = hdp->hd_vr;
 191         hdp->hd_rrtimer = 0;
 192
 193         if (hdp->hd_vs == hdp->hd_retxqi) {
 194                 /* Check for retransmissions. */
 195                 /* Put iframe only once in the Retransmission queue. */
 196                 hdp->hd_retxq[hdp->hd_retxqi] = buf;
 197                 hdp->hd_retxqi = (hdp->hd_retxqi + 1) % MODULUS;
 198                 hdp->hd_iframes_out++;
 199         }
 200
 201         hdp->hd_vs = (hdp->hd_vs + 1) % MODULUS;
 202
 203         hd_trace (hdp, TX, (struct Hdlc_frame *)iframe);
 204
 205         /* Write buffer on device. */
 206         m = hdp->hd_dontcopy ? buf : m_copy(buf, 0, (int)M_COPYALL);
 207         if (m == 0) {
 208                 printf("hdlc: out of mbufs\n");
 209                 return;
 210         }
 211         (*hdp->hd_output)(hdp, m);
 212         SET_TIMER (hdp);
 213 }
 214
 215 hd_ifoutput(hdp, m)
 216 register struct mbuf *m;
 217 register struct hdcb *hdp;
 218 {
 219         /*
 220          * Queue message on interface, and start output if interface
 221          * not yet active.
 222          */
 223         register struct ifnet *ifp = hdp->hd_ifp;
 224         int s = splimp();
 225
 226         if (IF_QFULL(&ifp->if_snd)) {
 227                 IF_DROP(&ifp->if_snd);
 228             /* printf("%s%d: HDLC says OK to send but queue full, may hang\n",
 229                         ifp->if_name, ifp->if_unit);*/
 230                 m_freem(m);
 231         } else {
 232                 IF_ENQUEUE(&ifp->if_snd, m);
 233                 if ((ifp->if_flags & IFF_OACTIVE) == 0)
 234                         (*ifp->if_start)(ifp);
 235         }
 236         splx(s);
 237 }
 238
 239
 240 /*
 241  *  This routine gets control when the timer expires because we have not
 242  *  received an acknowledgement for a iframe.
 243  */
 244
 245 hd_resend_iframe (hdp)
 246 register struct hdcb *hdp;
 247 {
 248
 249         if (hdp->hd_retxcnt++ < hd_n2) {
 250                 if (!(hdp->hd_condition & TIMER_RECOVERY_CONDITION)) {
 251                         hdp->hd_xx = hdp->hd_vs;
 252                         hdp->hd_condition |= TIMER_RECOVERY_CONDITION;
 253                 }
 254
 255                 hdp->hd_vs = hdp->hd_lastrxnr;
 256                 hd_send_iframe (hdp, hdp->hd_retxq[hdp->hd_vs], POLLON);
 257         } else {
 258                 /* At this point we have not received a RR even after N2
 259                    retries - attempt to reset link. */
 260
 261                 hd_initvars (hdp);
 262                 hd_writeinternal (hdp, SABM, POLLOFF);
 263                 hdp->hd_state = WAIT_UA;
 264                 SET_TIMER (hdp);
 265                 hd_message (hdp, "Timer recovery failed: link down");
 266                 (void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_pkp);
 267         }
 268 }