async.c revision 78189 
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 78189 2001-06-13 21:52:19Z 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->mode = MODE_HUNT;
60  async->length = 0;
61  async->my_accmap = async->his_accmap = 0xffffffff;
62  memset(async->cfg.EscMap, '\0', sizeof async->cfg.EscMap);
63}
64
65void
66async_SetLinkParams(struct async *async, struct lcp *lcp)
67{
68  async->my_accmap = lcp->want_accmap;
69  async->his_accmap = lcp->his_accmap | lcp->want_accmap;
70}
71
72/*
73 * Encode into async HDLC byte code
74 */
75static void
76async_Encode(struct async *async, u_char **cp, u_char c, int proto)
77{
78  u_char *wp;
79
80  wp = *cp;
81  if ((c < 0x20 && (proto == PROTO_LCP || (async->his_accmap & (1 << c))))
82      || (c == HDLC_ESC) || (c == HDLC_SYN)) {
83    *wp++ = HDLC_ESC;
84    c ^= HDLC_XOR;
85  }
86  if (async->cfg.EscMap[32] && async->cfg.EscMap[c >> 3] & (1 << (c & 7))) {
87    *wp++ = HDLC_ESC;
88    c ^= HDLC_XOR;
89  }
90  *wp++ = c;
91  *cp = wp;
92}
93
94static struct mbuf *
95async_LayerPush(struct bundle *bundle, struct link *l, struct mbuf *bp,
96                int pri, u_short *proto)
97{
98  struct physical *p = link2physical(l);
99  u_char *cp, *sp, *ep;
100  struct mbuf *wp;
101  int cnt;
102
103  if (!p || m_length(bp) > HDLCSIZE) {
104    m_freem(bp);
105    return NULL;
106  }
107
108  cp = p->async.xbuff;
109  ep = cp + HDLCSIZE - 10;
110  wp = bp;
111  *cp++ = HDLC_SYN;
112  while (wp) {
113    sp = MBUF_CTOP(wp);
114    for (cnt = wp->m_len; cnt > 0; cnt--) {
115      async_Encode(&p->async, &cp, *sp++, *proto);
116      if (cp >= ep) {
117	m_freem(bp);
118	return NULL;
119      }
120    }
121    wp = wp->m_next;
122  }
123  *cp++ = HDLC_SYN;
124
125  cnt = cp - p->async.xbuff;
126  m_freem(bp);
127  bp = m_get(cnt, MB_ASYNCOUT);
128  memcpy(MBUF_CTOP(bp), p->async.xbuff, cnt);
129  log_DumpBp(LogASYNC, "Write", bp);
130
131  return bp;
132}
133
134static struct mbuf *
135async_Decode(struct async *async, u_char c)
136{
137  struct mbuf *bp;
138
139  if ((async->mode & MODE_HUNT) && c != HDLC_SYN)
140    return NULL;
141
142  switch (c) {
143  case HDLC_SYN:
144    async->mode &= ~MODE_HUNT;
145    if (async->length) {		/* packet is ready. */
146      bp = m_get(async->length, MB_ASYNCIN);
147      mbuf_Write(bp, async->hbuff, async->length);
148      async->length = 0;
149      return bp;
150    }
151    break;
152  case HDLC_ESC:
153    if (!(async->mode & MODE_ESC)) {
154      async->mode |= MODE_ESC;
155      break;
156    }
157    /* Fall into ... */
158  default:
159    if (async->length >= HDLCSIZE) {
160      /* packet is too large, discard it */
161      log_Printf(LogWARN, "Packet too large (%d), discarding.\n",
162                 async->length);
163      async->length = 0;
164      async->mode = MODE_HUNT;
165      break;
166    }
167    if (async->mode & MODE_ESC) {
168      c ^= HDLC_XOR;
169      async->mode &= ~MODE_ESC;
170    }
171    async->hbuff[async->length++] = c;
172    break;
173  }
174  return NULL;
175}
176
177static struct mbuf *
178async_LayerPull(struct bundle *b, struct link *l, struct mbuf *bp,
179                u_short *proto)
180{
181  struct mbuf *nbp, **last;
182  struct physical *p = link2physical(l);
183  u_char *ch;
184  size_t cnt;
185
186  if (!p) {
187    log_Printf(LogERROR, "Can't Pull an async packet from a logical link\n");
188    return bp;
189  }
190
191  last = &nbp;
192
193  log_DumpBp(LogASYNC, "Read", bp);
194  while (bp) {
195    ch = MBUF_CTOP(bp);
196    for (cnt = bp->m_len; cnt; cnt--) {
197      *last = async_Decode(&p->async, *ch++);
198      if (*last != NULL)
199        last = &(*last)->m_nextpkt;
200    }
201    bp = m_free(bp);
202  }
203
204  return nbp;
205}
206
207struct layer asynclayer =
208  { LAYER_ASYNC, "async", async_LayerPush, async_LayerPull };
209