xref: /freebsd/usr.sbin/ppp/proto.c (revision d37eb51047221dc3322b34db1038ff3aa533883f)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 
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 "log.h"
38 #include "timer.h"
39 #include "fsm.h"
40 #include "mbuf.h"
41 #include "proto.h"
42 #include "throughput.h"
43 #include "lqr.h"
44 #include "hdlc.h"
45 #include "lcp.h"
46 #include "ccp.h"
47 #include "link.h"
48 
49 int
50 proto_WrapperOctets(struct lcp *lcp, u_short proto)
51 {
52   return (lcp->his_protocomp && !(proto & 0xff00)) ? 1 : 2;
53 }
54 
55 struct mbuf *
56 proto_Prepend(struct mbuf *bp, u_short proto, unsigned comp, int extra)
57 {
58   u_char cp[2];
59 
60   cp[0] = proto >> 8;
61   cp[1] = proto & 0xff;
62 
63   if (comp && cp[0] == 0)
64     bp = m_prepend(bp, cp + 1, 1, extra);
65   else
66     bp = m_prepend(bp, cp, 2, extra);
67 
68   return bp;
69 }
70 
71 static struct mbuf *
72 proto_LayerPush(struct bundle *b __unused, struct link *l, struct mbuf *bp,
73                 int pri __unused, u_short *proto)
74 {
75   log_Printf(LogDEBUG, "proto_LayerPush: Using 0x%04x\n", *proto);
76   bp = proto_Prepend(bp, *proto, l->lcp.his_protocomp,
77                      acf_WrapperOctets(&l->lcp, *proto));
78   m_settype(bp, MB_PROTOOUT);
79   link_ProtocolRecord(l, *proto, PROTO_OUT);
80 
81   return bp;
82 }
83 
84 static struct mbuf *
85 proto_LayerPull(struct bundle *b __unused, struct link *l, struct mbuf *bp,
86                 u_short *proto)
87 {
88   u_char cp[2];
89   size_t got;
90 
91   if ((got = mbuf_View(bp, cp, 2)) == 0) {
92     m_freem(bp);
93     return NULL;
94   }
95 
96   *proto = cp[0];
97   if (!(*proto & 1)) {
98     if (got == 1) {
99       m_freem(bp);
100       return NULL;
101     }
102     bp = mbuf_Read(bp, cp, 2);
103     *proto = (*proto << 8) | cp[1];
104   } else
105     bp = mbuf_Read(bp, cp, 1);
106 
107   log_Printf(LogDEBUG, "proto_LayerPull: unknown -> 0x%04x\n", *proto);
108   m_settype(bp, MB_PROTOIN);
109   link_ProtocolRecord(l, *proto, PROTO_IN);
110 
111   return bp;
112 }
113 
114 struct layer protolayer =
115   { LAYER_PROTO, "proto", proto_LayerPush, proto_LayerPull };
116