1/*	$OpenBSD: print-mpls.c,v 1.4 2018/07/06 07:00:49 dlg Exp $	*/
2
3/*
4 * Copyright (c) 2005 Jason L. Wright (jason@thought.net)
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 ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
20 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
24 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
25 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/socket.h>
30#include <sys/types.h>
31#include <netmpls/mpls.h>
32
33#include <stdio.h>
34
35#include "interface.h"
36#include "extract.h"		    /* must come after interface.h */
37
38#define CW_SEQUENCE_MASK       (0x0000ffffU)
39
40int controlword_tryprint(const u_char **, u_int *);
41
42void
43mpls_print(const u_char *bp, u_int len)
44{
45	u_int32_t tag, label, exp, bottom, ttl;
46	int has_cw;
47
48	do {
49		if (bp + sizeof(tag) > snapend)
50			goto trunc;
51
52		tag = EXTRACT_32BITS(bp);
53		bp += sizeof(tag);
54		len -= sizeof(tag);
55
56		label = (tag >> 12) & 0xfffff;
57		exp = (tag >> 9) & 0x7;
58		bottom = (tag >> 8) & 0x1;
59		ttl = (tag >> 0) & 0xff;
60
61		printf("MPLS(label %u, exp %u, ttl %u) ", label, exp, ttl);
62
63		/* XXX decode "Router Alert Label" */
64	} while (!bottom);
65
66	/* Handle pseudowire control word. */
67	has_cw = controlword_tryprint(&bp, &len);
68
69	/*
70	 * guessing the underlying protocol is about all we can do if
71	 * it's not explicitly defined.
72	 */
73
74	switch (label) {
75	case 0x00000:			/* IPv4 Explicit NULL */
76		ip_print(bp, len);
77		break;
78	case 0x00001:			/* Router Alert */
79		/* shouldn't happen at stack bottom */
80		printf("Route-Alert");
81		break;
82	case 0x00002:			/* IPv6 Explicit NULL */
83		ip6_print(bp, len);
84		break;
85	case 0x00003:			/* Implicit NULL */
86		/* shouldn't happen in the tag stack */
87		printf("Implicit-NULL");
88		break;
89
90	case 0x00004:			/* reserved labels */
91	case 0x00005:
92	case 0x00006:
93	case 0x00007:
94	case 0x00008:
95	case 0x00009:
96	case 0x0000a:
97	case 0x0000b:
98	case 0x0000c:
99	case 0x0000d:
100	case 0x0000e:
101	case 0x0000f:
102		break;
103
104	default:			/* dunno, guess? */
105		if (len == 0)
106			break;
107		if (bp >= snapend)
108			goto trunc;
109
110		switch (bp[0] & 0xf0) {
111		case 0x40:
112			ip_print(bp, len);
113			break;
114		case 0x60:
115			ip6_print(bp, len);
116			break;
117		}
118	}
119
120	if (has_cw)
121		ether_tryprint(bp, len, 0);
122
123	return;
124trunc:
125	printf("[|mpls]");
126}
127
128/* Print control word if any and returns 1 on success. */
129int
130controlword_tryprint(const u_char **bp, u_int *lenp)
131{
132	uint32_t cw, frag, seq;
133
134	if (*lenp < 4)
135		return (0);
136
137	cw = EXTRACT_32BITS(*bp);
138	if (cw & CW_ZERO_MASK)
139		return (0);
140
141	*bp += sizeof(cw);
142	*lenp += sizeof(cw);
143
144	frag = (cw & CW_FRAG_MASK) >> 16;
145	seq = cw & CW_SEQUENCE_MASK;
146
147	printf("CW(frag %u, sequence %u) ", frag, seq);
148
149	return (1);
150}
151