1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1999 Brian Somers <brian@Awfulhak.org>
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: stable/11/usr.sbin/ppp/acf.c 330449 2018-03-05 07:26:05Z eadler $
29 */
30
31#include <sys/types.h>
32
33#include <stdio.h>
34#include <termios.h>
35
36#include "defs.h"
37#include "layer.h"
38#include "timer.h"
39#include "fsm.h"
40#include "log.h"
41#include "mbuf.h"
42#include "acf.h"
43#include "proto.h"
44#include "throughput.h"
45#include "lqr.h"
46#include "hdlc.h"
47#include "lcp.h"
48#include "ccp.h"
49#include "link.h"
50#include "descriptor.h"
51#include "async.h"
52#include "physical.h"
53
54int
55acf_WrapperOctets(struct lcp *lcp, u_short proto)
56{
57  return (proto == PROTO_LCP || lcp->his_acfcomp == 0) ? 2 : 0;
58}
59
60static struct mbuf *
61acf_LayerPush(struct bundle *b __unused, struct link *l, struct mbuf *bp,
62              int pri __unused, u_short *proto)
63{
64  const u_char cp[2] = { HDLC_ADDR, HDLC_UI };
65
66  if (*proto == PROTO_LCP || l->lcp.his_acfcomp == 0) {
67    bp = m_prepend(bp, cp, 2, 0);
68    m_settype(bp, MB_ACFOUT);
69  }
70
71  return bp;
72}
73
74static struct mbuf *
75acf_LayerPull(struct bundle *b __unused, struct link *l, struct mbuf *bp,
76	      u_short *proto __unused)
77{
78  struct physical *p = link2physical(l);
79  u_char cp[2];
80
81  if (!p) {
82    log_Printf(LogERROR, "Can't Pull an acf packet from a logical link\n");
83    return bp;
84  }
85
86  if (mbuf_View(bp, cp, 2) == 2) {
87    if (!p->link.lcp.want_acfcomp) {
88      /* We expect the packet not to be compressed */
89      bp = mbuf_Read(bp, cp, 2);
90      if (cp[0] != HDLC_ADDR) {
91        p->hdlc.lqm.ifInErrors++;
92        p->hdlc.stats.badaddr++;
93        log_Printf(LogDEBUG, "acf_LayerPull: addr 0x%02x\n", cp[0]);
94        m_freem(bp);
95        return NULL;
96      }
97      if (cp[1] != HDLC_UI) {
98        p->hdlc.lqm.ifInErrors++;
99        p->hdlc.stats.badcommand++;
100        log_Printf(LogDEBUG, "acf_LayerPull: control 0x%02x\n", cp[1]);
101        m_freem(bp);
102        return NULL;
103      }
104      m_settype(bp, MB_ACFIN);
105    } else if (cp[0] == HDLC_ADDR && cp[1] == HDLC_UI) {
106      /*
107       * We can receive compressed packets, but the peer still sends
108       * uncompressed packets (or maybe this is a PROTO_LCP packet) !
109       */
110      bp = mbuf_Read(bp, cp, 2);
111      m_settype(bp, MB_ACFIN);
112    }
113  }
114
115  return bp;
116}
117
118struct layer acflayer = { LAYER_ACF, "acf", acf_LayerPush, acf_LayerPull };
119