xref: /freebsd/usr.sbin/ppp/layer.h (revision 315ee00f)
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 #define	LAYER_ASYNC	2
30 #define	LAYER_SYNC	3
31 #define	LAYER_HDLC	4
32 #define	LAYER_ACF	5
33 #define	LAYER_PROTO	6
34 #define	LAYER_LQR	7
35 #define	LAYER_CCP	8
36 #define	LAYER_VJ	9
37 #define	LAYER_NAT	10
38 
39 #define	LAYER_MAX	10	/* How many layers we can handle on a link */
40 
41 struct mbuf;
42 struct link;
43 struct bundle;
44 
45 struct layer {
46   int type;
47   const char *name;
48   struct mbuf *(*push)(struct bundle *, struct link *, struct mbuf *,
49                        int pri, u_short *proto);
50   struct mbuf *(*pull)(struct bundle *, struct link *, struct mbuf *,
51                        u_short *);
52 };
53