async.c revision 93418 
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: head/usr.sbin/ppp/async.c 93418 2002-03-30 12:30:09Z brian $
29 */
30
31#include <sys/types.h>
32
33#include <string.h>
34#include <termios.h>
35
36#include "layer.h"
37#include "mbuf.h"
38#include "log.h"
39#include "defs.h"
40#include "timer.h"
41#include "fsm.h"
42#include "lqr.h"
43#include "hdlc.h"
44#include "lcp.h"
45#include "proto.h"
46#include "async.h"
47#include "throughput.h"
48#include "ccp.h"
49#include "link.h"
50#include "descriptor.h"
51#include "physical.h"
52
53#define MODE_HUNT 0x01
54#define MODE_ESC  0x02
55
56void
57async_Init(struct async *async)
58{
59  async_Setup(async);
60  memset(async->cfg.EscMap, '\0', sizeof async->cfg.EscMap);
61}
62
63void
64async_Setup(struct async *async)
65{
66  async->mode = MODE_HUNT;
67  async->length = 0;
68  async->my_accmap = async->his_accmap = 0xffffffff;
69}
70
71void
72async_SetLinkParams(struct async *async, u_int32_t mymap, u_int32_t hismap)
73{
74  async->my_accmap = mymap;
75  async->his_accmap = hismap | mymap;
76}
77
78/*
79 * Encode into async HDLC byte code
80 */
81static void
82async_Encode(struct async *async, u_char **cp, u_char c, int proto)
83{
84  u_char *wp;
85
86  wp = *cp;
87  if ((c < 0x20 && (proto == PROTO_LCP || (async->his_accmap & (1 << c))))
88      || (c == HDLC_ESC) || (c == HDLC_SYN)) {
89    *wp++ = HDLC_ESC;
90    c ^= HDLC_XOR;
91  }
92  if (async->cfg.EscMap[32] && async->cfg.EscMap[c >> 3] & (1 << (c & 7))) {
93    *wp++ = HDLC_ESC;
94    c ^= HDLC_XOR;
95  }
96  *wp++ = c;
97  *cp = wp;
98}
99
100static struct mbuf *
101async_LayerPush(struct bundle *bundle, struct link *l, struct mbuf *bp,
102                int pri, u_short *proto)
103{
104  struct physical *p = link2physical(l);
105  u_char *cp, *sp, *ep;
106  struct mbuf *wp;
107  int cnt;
108
109  if (!p || m_length(bp) > HDLCSIZE) {
110    m_freem(bp);
111    return NULL;
112  }
113
114  cp = p->async.xbuff;
115  ep = cp + HDLCSIZE - 10;
116  wp = bp;
117  *cp++ = HDLC_SYN;
118  while (wp) {
119    sp = MBUF_CTOP(wp);
120    for (cnt = wp->m_len; cnt > 0; cnt--) {
121      async_Encode(&p->async, &cp, *sp++, *proto);
122      if (cp >= ep) {
123	m_freem(bp);
124	return NULL;
125      }
126    }
127    wp = wp->m_next;
128  }
129  *cp++ = HDLC_SYN;
130
131  cnt = cp - p->async.xbuff;
132  m_freem(bp);
133  bp = m_get(cnt, MB_ASYNCOUT);
134  memcpy(MBUF_CTOP(bp), p->async.xbuff, cnt);
135  log_DumpBp(LogASYNC, "Write", bp);
136
137  return bp;
138}
139
140static struct mbuf *
141async_Decode(struct async *async, u_char c)
142{
143  struct mbuf *bp;
144
145  if ((async->mode & MODE_HUNT) && c != HDLC_SYN)
146    return NULL;
147
148  switch (c) {
149  case HDLC_SYN:
150    async->mode &= ~MODE_HUNT;
151    if (async->length) {		/* packet is ready. */
152      bp = m_get(async->length, MB_ASYNCIN);
153      mbuf_Write(bp, async->hbuff, async->length);
154      async->length = 0;
155      return bp;
156    }
157    break;
158  case HDLC_ESC:
159    if (!(async->mode & MODE_ESC)) {
160      async->mode |= MODE_ESC;
161      break;
162    }
163    /* Fall into ... */
164  default:
165    if (async->length >= HDLCSIZE) {
166      /* packet is too large, discard it */
167      log_Printf(LogWARN, "Packet too large (%d), discarding.\n",
168                 async->length);
169      async->length = 0;
170      async->mode = MODE_HUNT;
171      break;
172    }
173    if (async->mode & MODE_ESC) {
174      c ^= HDLC_XOR;
175      async->mode &= ~MODE_ESC;
176    }
177    async->hbuff[async->length++] = c;
178    break;
179  }
180  return NULL;
181}
182
183static struct mbuf *
184async_LayerPull(struct bundle *b, struct link *l, struct mbuf *bp,
185                u_short *proto)
186{
187  struct mbuf *nbp, **last;
188  struct physical *p = link2physical(l);
189  u_char *ch;
190  size_t cnt;
191
192  if (!p) {
193    log_Printf(LogERROR, "Can't Pull an async packet from a logical link\n");
194    return bp;
195  }
196
197  last = &nbp;
198
199  log_DumpBp(LogASYNC, "Read", bp);
200  while (bp) {
201    ch = MBUF_CTOP(bp);
202    for (cnt = bp->m_len; cnt; cnt--) {
203      *last = async_Decode(&p->async, *ch++);
204      if (*last != NULL)
205        last = &(*last)->m_nextpkt;
206    }
207    bp = m_free(bp);
208  }
209
210  return nbp;
211}
212
213struct layer asynclayer =
214  { LAYER_ASYNC, "async", async_LayerPush, async_LayerPull };
215