xref: /freebsd/usr.sbin/ppp/acf.c (revision 3c5ba95ad12285ad37c182a4bfc1b240ec6d18a7)
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  * $FreeBSD$
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 
54 int
55 acf_WrapperOctets(struct lcp *lcp, u_short proto)
56 {
57   return (proto == PROTO_LCP || lcp->his_acfcomp == 0) ? 2 : 0;
58 }
59 
60 static struct mbuf *
61 acf_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 
74 static struct mbuf *
75 acf_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 
118 struct layer acflayer = { LAYER_ACF, "acf", acf_LayerPush, acf_LayerPull };
119