async.c revision 102413 
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: head/usr.sbin/ppp/async.c 102413 2002-08-25 13:30:43Z charnier $");
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
58void
59async_Init(struct async *async)
60{
61  async_Setup(async);
62  memset(async->cfg.EscMap, '\0', sizeof async->cfg.EscMap);
63}
64
65void
66async_Setup(struct async *async)
67{
68  async->mode = MODE_HUNT;
69  async->length = 0;
70  async->my_accmap = async->his_accmap = 0xffffffff;
71}
72
73void
74async_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 */
83static void
84async_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
102static struct mbuf *
103async_LayerPush(struct bundle *bundle, struct link *l, struct mbuf *bp,
104                int pri, u_short *proto)
105{
106  struct physical *p = link2physical(l);
107  u_char *cp, *sp, *ep;
108  struct mbuf *wp;
109  int cnt;
110
111  if (!p || m_length(bp) > HDLCSIZE) {
112    m_freem(bp);
113    return NULL;
114  }
115
116  cp = p->async.xbuff;
117  ep = cp + HDLCSIZE - 10;
118  wp = bp;
119  *cp++ = HDLC_SYN;
120  while (wp) {
121    sp = MBUF_CTOP(wp);
122    for (cnt = wp->m_len; cnt > 0; cnt--) {
123      async_Encode(&p->async, &cp, *sp++, *proto);
124      if (cp >= ep) {
125	m_freem(bp);
126	return NULL;
127      }
128    }
129    wp = wp->m_next;
130  }
131  *cp++ = HDLC_SYN;
132
133  cnt = cp - p->async.xbuff;
134  m_freem(bp);
135  bp = m_get(cnt, MB_ASYNCOUT);
136  memcpy(MBUF_CTOP(bp), p->async.xbuff, cnt);
137  log_DumpBp(LogASYNC, "Write", bp);
138
139  return bp;
140}
141
142static struct mbuf *
143async_Decode(struct async *async, u_char c)
144{
145  struct mbuf *bp;
146
147  if ((async->mode & MODE_HUNT) && c != HDLC_SYN)
148    return NULL;
149
150  switch (c) {
151  case HDLC_SYN:
152    async->mode &= ~MODE_HUNT;
153    if (async->length) {		/* packet is ready. */
154      bp = m_get(async->length, MB_ASYNCIN);
155      mbuf_Write(bp, async->hbuff, async->length);
156      async->length = 0;
157      return bp;
158    }
159    break;
160  case HDLC_ESC:
161    if (!(async->mode & MODE_ESC)) {
162      async->mode |= MODE_ESC;
163      break;
164    }
165    /* FALLTHROUGH */
166  default:
167    if (async->length >= HDLCSIZE) {
168      /* packet is too large, discard it */
169      log_Printf(LogWARN, "Packet too large (%d), discarding.\n",
170                 async->length);
171      async->length = 0;
172      async->mode = MODE_HUNT;
173      break;
174    }
175    if (async->mode & MODE_ESC) {
176      c ^= HDLC_XOR;
177      async->mode &= ~MODE_ESC;
178    }
179    async->hbuff[async->length++] = c;
180    break;
181  }
182  return NULL;
183}
184
185static struct mbuf *
186async_LayerPull(struct bundle *b, struct link *l, struct mbuf *bp,
187                u_short *proto)
188{
189  struct mbuf *nbp, **last;
190  struct physical *p = link2physical(l);
191  u_char *ch;
192  size_t cnt;
193
194  if (!p) {
195    log_Printf(LogERROR, "Can't Pull an async packet from a logical link\n");
196    return bp;
197  }
198
199  last = &nbp;
200
201  log_DumpBp(LogASYNC, "Read", bp);
202  while (bp) {
203    ch = MBUF_CTOP(bp);
204    for (cnt = bp->m_len; cnt; cnt--) {
205      *last = async_Decode(&p->async, *ch++);
206      if (*last != NULL)
207        last = &(*last)->m_nextpkt;
208    }
209    bp = m_free(bp);
210  }
211
212  return nbp;
213}
214
215struct layer asynclayer =
216  { LAYER_ASYNC, "async", async_LayerPush, async_LayerPull };
217