1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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/cdefs.h>
33__FBSDID("$FreeBSD: stable/11/usr.sbin/ppp/async.c 330449 2018-03-05 07:26:05Z eadler $");
34
35#include <sys/types.h>
36
37#include <string.h>
38#include <termios.h>
39
40#include "layer.h"
41#include "mbuf.h"
42#include "log.h"
43#include "defs.h"
44#include "timer.h"
45#include "fsm.h"
46#include "lqr.h"
47#include "hdlc.h"
48#include "lcp.h"
49#include "proto.h"
50#include "async.h"
51#include "throughput.h"
52#include "ccp.h"
53#include "link.h"
54#include "descriptor.h"
55#include "physical.h"
56
57#define MODE_HUNT 0x01
58#define MODE_ESC  0x02
59
60void
61async_Init(struct async *async)
62{
63  async_Setup(async);
64  memset(async->cfg.EscMap, '\0', sizeof async->cfg.EscMap);
65}
66
67void
68async_Setup(struct async *async)
69{
70  async->mode = MODE_HUNT;
71  async->length = 0;
72  async->my_accmap = async->his_accmap = 0xffffffff;
73}
74
75void
76async_SetLinkParams(struct async *async, u_int32_t mymap, u_int32_t hismap)
77{
78  async->my_accmap = mymap;
79  async->his_accmap = hismap | mymap;
80}
81
82/*
83 * Encode into async HDLC byte code
84 */
85static void
86async_Encode(struct async *async, u_char **cp, u_char c, int proto)
87{
88  u_char *wp;
89
90  wp = *cp;
91  if ((c < 0x20 && (proto == PROTO_LCP || (async->his_accmap & (1 << c))))
92      || (c == HDLC_ESC) || (c == HDLC_SYN)) {
93    *wp++ = HDLC_ESC;
94    c ^= HDLC_XOR;
95  }
96  if (async->cfg.EscMap[32] && async->cfg.EscMap[c >> 3] & (1 << (c & 7))) {
97    *wp++ = HDLC_ESC;
98    c ^= HDLC_XOR;
99  }
100  *wp++ = c;
101  *cp = wp;
102}
103
104static struct mbuf *
105async_LayerPush(struct bundle *b __unused, struct link *l, struct mbuf *bp,
106                int pri __unused, u_short *proto)
107{
108  struct physical *p = link2physical(l);
109  u_char *cp, *sp, *ep;
110  struct mbuf *wp;
111  size_t oldcnt;
112  size_t cnt;
113
114  if (!p || m_length(bp) > HDLCSIZE) {
115    m_freem(bp);
116    return NULL;
117  }
118
119  oldcnt = m_length(bp);
120
121  cp = p->async.xbuff;
122  ep = cp + HDLCSIZE - 10;
123  wp = bp;
124  *cp++ = HDLC_SYN;
125  while (wp) {
126    sp = MBUF_CTOP(wp);
127    for (cnt = wp->m_len; cnt > 0; cnt--) {
128      async_Encode(&p->async, &cp, *sp++, *proto);
129      if (cp >= ep) {
130	m_freem(bp);
131	return NULL;
132      }
133    }
134    wp = wp->m_next;
135  }
136  *cp++ = HDLC_SYN;
137
138  cnt = cp - p->async.xbuff;
139  m_freem(bp);
140  bp = m_get(cnt, MB_ASYNCOUT);
141  memcpy(MBUF_CTOP(bp), p->async.xbuff, cnt);
142  bp->priv = cnt - oldcnt;
143  log_DumpBp(LogASYNC, "Write", bp);
144
145  return bp;
146}
147
148static struct mbuf *
149async_Decode(struct async *async, u_char c)
150{
151  struct mbuf *bp;
152
153  if ((async->mode & MODE_HUNT) && c != HDLC_SYN)
154    return NULL;
155
156  switch (c) {
157  case HDLC_SYN:
158    async->mode &= ~MODE_HUNT;
159    if (async->length) {		/* packet is ready. */
160      bp = m_get(async->length, MB_ASYNCIN);
161      mbuf_Write(bp, async->hbuff, async->length);
162      async->length = 0;
163      return bp;
164    }
165    break;
166  case HDLC_ESC:
167    if (!(async->mode & MODE_ESC)) {
168      async->mode |= MODE_ESC;
169      break;
170    }
171    /* FALLTHROUGH */
172  default:
173    if (async->length >= HDLCSIZE) {
174      /* packet is too large, discard it */
175      log_Printf(LogWARN, "Packet too large (%d), discarding.\n",
176                 async->length);
177      async->length = 0;
178      async->mode = MODE_HUNT;
179      break;
180    }
181    if (async->mode & MODE_ESC) {
182      c ^= HDLC_XOR;
183      async->mode &= ~MODE_ESC;
184    }
185    async->hbuff[async->length++] = c;
186    break;
187  }
188  return NULL;
189}
190
191static struct mbuf *
192async_LayerPull(struct bundle *b __unused, struct link *l, struct mbuf *bp,
193                u_short *proto __unused)
194{
195  struct mbuf *nbp, **last;
196  struct physical *p = link2physical(l);
197  u_char *ch;
198  size_t cnt;
199
200  if (!p) {
201    log_Printf(LogERROR, "Can't Pull an async packet from a logical link\n");
202    return bp;
203  }
204
205  last = &nbp;
206
207  log_DumpBp(LogASYNC, "Read", bp);
208  while (bp) {
209    ch = MBUF_CTOP(bp);
210    for (cnt = bp->m_len; cnt; cnt--) {
211      *last = async_Decode(&p->async, *ch++);
212      if (*last != NULL)
213        last = &(*last)->m_nextpkt;
214    }
215    bp = m_free(bp);
216  }
217
218  return nbp;
219}
220
221struct layer asynclayer =
222  { LAYER_ASYNC, "async", async_LayerPush, async_LayerPull };
223