1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org>
5 *          based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
6 *                           Internet Initiative Japan, Inc (IIJ)
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
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
57void
58async_Init(struct async *async)
59{
60  async_Setup(async);
61  memset(async->cfg.EscMap, '\0', sizeof async->cfg.EscMap);
62}
63
64void
65async_Setup(struct async *async)
66{
67  async->mode = MODE_HUNT;
68  async->length = 0;
69  async->my_accmap = async->his_accmap = 0xffffffff;
70}
71
72void
73async_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 */
82static void
83async_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
101static struct mbuf *
102async_LayerPush(struct bundle *b __unused, struct link *l, struct mbuf *bp,
103                int pri __unused, u_short *proto)
104{
105  struct physical *p = link2physical(l);
106  u_char *cp, *sp, *ep;
107  struct mbuf *wp;
108  size_t oldcnt;
109  size_t cnt;
110
111  if (!p || m_length(bp) > HDLCSIZE) {
112    m_freem(bp);
113    return NULL;
114  }
115
116  oldcnt = m_length(bp);
117
118  cp = p->async.xbuff;
119  ep = cp + HDLCSIZE - 10;
120  wp = bp;
121  *cp++ = HDLC_SYN;
122  while (wp) {
123    sp = MBUF_CTOP(wp);
124    for (cnt = wp->m_len; cnt > 0; cnt--) {
125      async_Encode(&p->async, &cp, *sp++, *proto);
126      if (cp >= ep) {
127	m_freem(bp);
128	return NULL;
129      }
130    }
131    wp = wp->m_next;
132  }
133  *cp++ = HDLC_SYN;
134
135  cnt = cp - p->async.xbuff;
136  m_freem(bp);
137  bp = m_get(cnt, MB_ASYNCOUT);
138  memcpy(MBUF_CTOP(bp), p->async.xbuff, cnt);
139  bp->priv = cnt - oldcnt;
140  log_DumpBp(LogASYNC, "Write", bp);
141
142  return bp;
143}
144
145static struct mbuf *
146async_Decode(struct async *async, u_char c)
147{
148  struct mbuf *bp;
149
150  if ((async->mode & MODE_HUNT) && c != HDLC_SYN)
151    return NULL;
152
153  switch (c) {
154  case HDLC_SYN:
155    async->mode &= ~MODE_HUNT;
156    if (async->length) {		/* packet is ready. */
157      bp = m_get(async->length, MB_ASYNCIN);
158      mbuf_Write(bp, async->hbuff, async->length);
159      async->length = 0;
160      return bp;
161    }
162    break;
163  case HDLC_ESC:
164    if (!(async->mode & MODE_ESC)) {
165      async->mode |= MODE_ESC;
166      break;
167    }
168    /* FALLTHROUGH */
169  default:
170    if (async->length >= HDLCSIZE) {
171      /* packet is too large, discard it */
172      log_Printf(LogWARN, "Packet too large (%d), discarding.\n",
173                 async->length);
174      async->length = 0;
175      async->mode = MODE_HUNT;
176      break;
177    }
178    if (async->mode & MODE_ESC) {
179      c ^= HDLC_XOR;
180      async->mode &= ~MODE_ESC;
181    }
182    async->hbuff[async->length++] = c;
183    break;
184  }
185  return NULL;
186}
187
188static struct mbuf *
189async_LayerPull(struct bundle *b __unused, struct link *l, struct mbuf *bp,
190                u_short *proto __unused)
191{
192  struct mbuf *nbp, **last;
193  struct physical *p = link2physical(l);
194  u_char *ch;
195  size_t cnt;
196
197  if (!p) {
198    log_Printf(LogERROR, "Can't Pull an async packet from a logical link\n");
199    return bp;
200  }
201
202  last = &nbp;
203
204  log_DumpBp(LogASYNC, "Read", bp);
205  while (bp) {
206    ch = MBUF_CTOP(bp);
207    for (cnt = bp->m_len; cnt; cnt--) {
208      *last = async_Decode(&p->async, *ch++);
209      if (*last != NULL)
210        last = &(*last)->m_nextpkt;
211    }
212    bp = m_free(bp);
213  }
214
215  return nbp;
216}
217
218struct layer asynclayer =
219  { LAYER_ASYNC, "async", async_LayerPush, async_LayerPull };
220