usr.sbin/ppp/async.c

   1 /*-
   2  * Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org>
   3  *          based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
   4  *                           Internet Initiative Japan, Inc (IIJ)
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  * $FreeBSD: src/usr.sbin/ppp/async.c,v 1.23.2.3 2002/09/01 02:12:22 brian Exp $
  29  * $DragonFly: src/usr.sbin/ppp/async.c,v 1.2 2003/06/17 04:30:00 dillon Exp $
  30  */
  31
  32 #include <sys/types.h>
  33
  34 #include <string.h>
  35 #include <termios.h>
  36
  37 #include "layer.h"
  38 #include "mbuf.h"
  39 #include "log.h"
  40 #include "defs.h"
  41 #include "timer.h"
  42 #include "fsm.h"
  43 #include "lqr.h"
  44 #include "hdlc.h"
  45 #include "lcp.h"
  46 #include "proto.h"
  47 #include "async.h"
  48 #include "throughput.h"
  49 #include "ccp.h"
  50 #include "link.h"
  51 #include "descriptor.h"
  52 #include "physical.h"
  53
  54 #define MODE_HUNT 0x01
  55 #define MODE_ESC  0x02
  56
  57 void
  58 async_Init(struct async *async)
  59 {
  60   async_Setup(async);
  61   memset(async->cfg.EscMap, '\0', sizeof async->cfg.EscMap);
  62 }
  63
  64 void
  65 async_Setup(struct async *async)
  66 {
  67   async->mode = MODE_HUNT;
  68   async->length = 0;
  69   async->my_accmap = async->his_accmap = 0xffffffff;
  70 }
  71
  72 void
  73 async_SetLinkParams(struct async *async, u_int32_t mymap, u_int32_t hismap)
  74 {
  75   async->my_accmap = mymap;
  76   async->his_accmap = hismap | mymap;
  77 }
  78
  79 /*
  80  * Encode into async HDLC byte code
  81  */
  82 static void
  83 async_Encode(struct async *async, u_char **cp, u_char c, int proto)
  84 {
  85   u_char *wp;
  86
  87   wp = *cp;
  88   if ((c < 0x20 && (proto == PROTO_LCP || (async->his_accmap & (1 << c))))
  89       || (c == HDLC_ESC) || (c == HDLC_SYN)) {
  90     *wp++ = HDLC_ESC;
  91     c ^= HDLC_XOR;
  92   }
  93   if (async->cfg.EscMap[32] && async->cfg.EscMap[c >> 3] & (1 << (c & 7))) {
  94     *wp++ = HDLC_ESC;
  95     c ^= HDLC_XOR;
  96   }
  97   *wp++ = c;
  98   *cp = wp;
  99 }
 100
 101 static struct mbuf *
 102 async_LayerPush(struct bundle *bundle, struct link *l, struct mbuf *bp,
 103                 int pri, u_short *proto)
 104 {
 105   struct physical *p = link2physical(l);
 106   u_char *cp, *sp, *ep;
 107   struct mbuf *wp;
 108   int cnt;
 109
 110   if (!p || m_length(bp) > HDLCSIZE) {
 111     m_freem(bp);
 112     return NULL;
 113   }
 114
 115   cp = p->async.xbuff;
 116   ep = cp + HDLCSIZE - 10;
 117   wp = bp;
 118   *cp++ = HDLC_SYN;
 119   while (wp) {
 120     sp = MBUF_CTOP(wp);
 121     for (cnt = wp->m_len; cnt > 0; cnt--) {
 122       async_Encode(&p->async, &cp, *sp++, *proto);
 123       if (cp >= ep) {
 124         m_freem(bp);
 125         return NULL;
 126       }
 127     }
 128     wp = wp->m_next;
 129   }
 130   *cp++ = HDLC_SYN;
 131
 132   cnt = cp - p->async.xbuff;
 133   m_freem(bp);
 134   bp = m_get(cnt, MB_ASYNCOUT);
 135   memcpy(MBUF_CTOP(bp), p->async.xbuff, cnt);
 136   log_DumpBp(LogASYNC, "Write", bp);
 137
 138   return bp;
 139 }
 140
 141 static struct mbuf *
 142 async_Decode(struct async *async, u_char c)
 143 {
 144   struct mbuf *bp;
 145
 146   if ((async->mode & MODE_HUNT) && c != HDLC_SYN)
 147     return NULL;
 148
 149   switch (c) {
 150   case HDLC_SYN:
 151     async->mode &= ~MODE_HUNT;
 152     if (async->length) {                /* packet is ready. */
 153       bp = m_get(async->length, MB_ASYNCIN);
 154       mbuf_Write(bp, async->hbuff, async->length);
 155       async->length = 0;
 156       return bp;
 157     }
 158     break;
 159   case HDLC_ESC:
 160     if (!(async->mode & MODE_ESC)) {
 161       async->mode |= MODE_ESC;
 162       break;
 163     }
 164     /* FALLTHROUGH */
 165   default:
 166     if (async->length >= HDLCSIZE) {
 167       /* packet is too large, discard it */
 168       log_Printf(LogWARN, "Packet too large (%d), discarding.\n",
 169                  async->length);
 170       async->length = 0;
 171       async->mode = MODE_HUNT;
 172       break;
 173     }
 174     if (async->mode & MODE_ESC) {
 175       c ^= HDLC_XOR;
 176       async->mode &= ~MODE_ESC;
 177     }
 178     async->hbuff[async->length++] = c;
 179     break;
 180   }
 181   return NULL;
 182 }
 183
 184 static struct mbuf *
 185 async_LayerPull(struct bundle *b, struct link *l, struct mbuf *bp,
 186                 u_short *proto)
 187 {
 188   struct mbuf *nbp, **last;
 189   struct physical *p = link2physical(l);
 190   u_char *ch;
 191   size_t cnt;
 192
 193   if (!p) {
 194     log_Printf(LogERROR, "Can't Pull an async packet from a logical link\n");
 195     return bp;
 196   }
 197
 198   last = &nbp;
 199
 200   log_DumpBp(LogASYNC, "Read", bp);
 201   while (bp) {
 202     ch = MBUF_CTOP(bp);
 203     for (cnt = bp->m_len; cnt; cnt--) {
 204       *last = async_Decode(&p->async, *ch++);
 205       if (*last != NULL)
 206         last = &(*last)->m_nextpkt;
 207     }
 208     bp = m_free(bp);
 209   }
 210
 211   return nbp;
 212 }
 213
 214 struct layer asynclayer =
 215   { LAYER_ASYNC, "async", async_LayerPush, async_LayerPull };