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  */
  29
  30 #include <sys/cdefs.h>
  31 __FBSDID("$FreeBSD$");
  32
  33 #include <sys/types.h>
  34
  35 #include <string.h>
  36 #include <termios.h>
  37
  38 #include "layer.h"
  39 #include "mbuf.h"
  40 #include "log.h"
  41 #include "defs.h"
  42 #include "timer.h"
  43 #include "fsm.h"
  44 #include "lqr.h"
  45 #include "hdlc.h"
  46 #include "lcp.h"
  47 #include "proto.h"
  48 #include "async.h"
  49 #include "throughput.h"
  50 #include "ccp.h"
  51 #include "link.h"
  52 #include "descriptor.h"
  53 #include "physical.h"
  54
  55 #define MODE_HUNT 0x01
  56 #define MODE_ESC  0x02
  57
  58 void
  59 async_Init(struct async *async)
  60 {
  61   async_Setup(async);
  62   memset(async->cfg.EscMap, '\0', sizeof async->cfg.EscMap);
  63 }
  64
  65 void
  66 async_Setup(struct async *async)
  67 {
  68   async->mode = MODE_HUNT;
  69   async->length = 0;
  70   async->my_accmap = async->his_accmap = 0xffffffff;
  71 }
  72
  73 void
  74 async_SetLinkParams(struct async *async, u_int32_t mymap, u_int32_t hismap)
  75 {
  76   async->my_accmap = mymap;
  77   async->his_accmap = hismap | mymap;
  78 }
  79
  80 /*
  81  * Encode into async HDLC byte code
  82  */
  83 static void
  84 async_Encode(struct async *async, u_char **cp, u_char c, int proto)
  85 {
  86   u_char *wp;
  87
  88   wp = *cp;
  89   if ((c < 0x20 && (proto == PROTO_LCP || (async->his_accmap & (1 << c))))
  90       || (c == HDLC_ESC) || (c == HDLC_SYN)) {
  91     *wp++ = HDLC_ESC;
  92     c ^= HDLC_XOR;
  93   }
  94   if (async->cfg.EscMap[32] && async->cfg.EscMap[c >> 3] & (1 << (c & 7))) {
  95     *wp++ = HDLC_ESC;
  96     c ^= HDLC_XOR;
  97   }
  98   *wp++ = c;
  99   *cp = wp;
 100 }
 101
 102 static struct mbuf *
 103 async_LayerPush(struct bundle *b __unused, struct link *l, struct mbuf *bp,
 104                 int pri __unused, u_short *proto)
 105 {
 106   struct physical *p = link2physical(l);
 107   u_char *cp, *sp, *ep;
 108   struct mbuf *wp;
 109   size_t oldcnt;
 110   size_t cnt;
 111
 112   if (!p || m_length(bp) > HDLCSIZE) {
 113     m_freem(bp);
 114     return NULL;
 115   }
 116
 117   oldcnt = m_length(bp);
 118
 119   cp = p->async.xbuff;
 120   ep = cp + HDLCSIZE - 10;
 121   wp = bp;
 122   *cp++ = HDLC_SYN;
 123   while (wp) {
 124     sp = MBUF_CTOP(wp);
 125     for (cnt = wp->m_len; cnt > 0; cnt--) {
 126       async_Encode(&p->async, &cp, *sp++, *proto);
 127       if (cp >= ep) {
 128         m_freem(bp);
 129         return NULL;
 130       }
 131     }
 132     wp = wp->m_next;
 133   }
 134   *cp++ = HDLC_SYN;
 135
 136   cnt = cp - p->async.xbuff;
 137   m_freem(bp);
 138   bp = m_get(cnt, MB_ASYNCOUT);
 139   memcpy(MBUF_CTOP(bp), p->async.xbuff, cnt);
 140   bp->priv = cnt - oldcnt;
 141   log_DumpBp(LogASYNC, "Write", bp);
 142
 143   return bp;
 144 }
 145
 146 static struct mbuf *
 147 async_Decode(struct async *async, u_char c)
 148 {
 149   struct mbuf *bp;
 150
 151   if ((async->mode & MODE_HUNT) && c != HDLC_SYN)
 152     return NULL;
 153
 154   switch (c) {
 155   case HDLC_SYN:
 156     async->mode &= ~MODE_HUNT;
 157     if (async->length) {                /* packet is ready. */
 158       bp = m_get(async->length, MB_ASYNCIN);
 159       mbuf_Write(bp, async->hbuff, async->length);
 160       async->length = 0;
 161       return bp;
 162     }
 163     break;
 164   case HDLC_ESC:
 165     if (!(async->mode & MODE_ESC)) {
 166       async->mode |= MODE_ESC;
 167       break;
 168     }
 169     /* FALLTHROUGH */
 170   default:
 171     if (async->length >= HDLCSIZE) {
 172       /* packet is too large, discard it */
 173       log_Printf(LogWARN, "Packet too large (%d), discarding.\n",
 174                  async->length);
 175       async->length = 0;
 176       async->mode = MODE_HUNT;
 177       break;
 178     }
 179     if (async->mode & MODE_ESC) {
 180       c ^= HDLC_XOR;
 181       async->mode &= ~MODE_ESC;
 182     }
 183     async->hbuff[async->length++] = c;
 184     break;
 185   }
 186   return NULL;
 187 }
 188
 189 static struct mbuf *
 190 async_LayerPull(struct bundle *b __unused, struct link *l, struct mbuf *bp,
 191                 u_short *proto __unused)
 192 {
 193   struct mbuf *nbp, **last;
 194   struct physical *p = link2physical(l);
 195   u_char *ch;
 196   size_t cnt;
 197
 198   if (!p) {
 199     log_Printf(LogERROR, "Can't Pull an async packet from a logical link\n");
 200     return bp;
 201   }
 202
 203   last = &nbp;
 204
 205   log_DumpBp(LogASYNC, "Read", bp);
 206   while (bp) {
 207     ch = MBUF_CTOP(bp);
 208     for (cnt = bp->m_len; cnt; cnt--) {
 209       *last = async_Decode(&p->async, *ch++);
 210       if (*last != NULL)
 211         last = &(*last)->m_nextpkt;
 212     }
 213     bp = m_free(bp);
 214   }
 215
 216   return nbp;
 217 }
 218
 219 struct layer asynclayer =
 220   { LAYER_ASYNC, "async", async_LayerPush, async_LayerPull };