proto.c revision 46686 
1/*-
2 * Copyright (c) 1999 Brian Somers <brian@Awfulhak.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 *	$Id:$
27 */
28
29#include <sys/types.h>
30
31#include <stdio.h>
32#include <termios.h>
33
34#include "layer.h"
35#include "acf.h"
36#include "defs.h"
37#include "timer.h"
38#include "fsm.h"
39#include "mbuf.h"
40#include "proto.h"
41#include "lcp.h"
42#include "throughput.h"
43#include "lqr.h"
44#include "hdlc.h"
45#include "ccp.h"
46#include "link.h"
47
48int
49proto_WrapperOctets(struct lcp *lcp, u_short proto)
50{
51  return (lcp->his_protocomp && !(proto & 0xff00)) ? 1 : 2;
52}
53
54struct mbuf *
55proto_Prepend(struct mbuf *bp, u_short proto, unsigned comp, int extra)
56{
57  u_char cp[2];
58
59  cp[0] = proto >> 8;
60  cp[1] = proto & 0xff;
61
62  if (comp && cp[0] == 0)
63    bp = mbuf_Prepend(bp, cp + 1, 1, extra);
64  else
65    bp = mbuf_Prepend(bp, cp, 2, extra);
66
67  return bp;
68}
69
70static struct mbuf *
71proto_LayerPush(struct bundle *b, struct link *l, struct mbuf *bp,
72                int pri, u_short *proto)
73{
74  bp = proto_Prepend(bp, *proto, l->lcp.his_protocomp,
75                     acf_WrapperOctets(&l->lcp, *proto));
76  link_ProtocolRecord(l, *proto, PROTO_OUT);
77
78  return bp;
79}
80
81static struct mbuf *
82proto_LayerPull(struct bundle *b, struct link *l, struct mbuf *bp,
83                u_short *proto)
84{
85  u_char cp[2];
86  size_t got;
87
88  if ((got = mbuf_View(bp, cp, 2)) == 0) {
89    mbuf_Free(bp);
90    return NULL;
91  }
92
93  *proto = cp[0];
94  if (!(*proto & 1)) {
95    if (got == 1) {
96      mbuf_Free(bp);
97      return NULL;
98    }
99    bp = mbuf_Read(bp, cp, 2);
100    *proto = (*proto << 8) | cp[1];
101  } else
102    bp = mbuf_Read(bp, cp, 1);
103
104  link_ProtocolRecord(l, *proto, PROTO_IN);
105
106  return bp;
107}
108
109struct layer protolayer =
110  { LAYER_PROTO, "proto", proto_LayerPush, proto_LayerPull };
111