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
40 int controlword_tryprint(const u_char **, u_int *);
41
42 void
mpls_print(const u_char * bp,u_int len)43 mpls_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;
124 trunc:
125 printf("[|mpls]");
126 }
127
128 /* Print control word if any and returns 1 on success. */
129 int
controlword_tryprint(const u_char ** bp,u_int * lenp)130 controlword_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