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1 | /* |
2 | * $Id: libnet_build_mpls.c,v 1.19 2005/11/29 22:55:14 carlosc Exp $ | |
3 | * | |
4 | * libnet | |
5 | * libnet_build_mpls.c - MPLS packet assembler | |
6 | * | |
7 | * Copyright (c) 1998 - 2004 Mike D. Schiffman <mike@infonexus.com> | |
8 | * All rights reserved. | |
9 | * | |
10 | * Redistribution and use in source and binary forms, with or without | |
11 | * modification, are permitted provided that the following conditions | |
12 | * are met: | |
13 | * 1. Redistributions of source code must retain the above copyright | |
14 | * notice, this list of conditions and the following disclaimer. | |
15 | * 2. Redistributions in binary form must reproduce the above copyright | |
16 | * notice, this list of conditions and the following disclaimer in the | |
17 | * documentation and/or other materials provided with the distribution. | |
18 | * | |
19 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND | |
20 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
21 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
22 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |
23 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
24 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
25 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
26 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
27 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
28 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
29 | * SUCH DAMAGE. | |
30 | * | |
31 | */ | |
32 | ||
33 | #if (HAVE_CONFIG_H) | |
34 | #include "../include/config.h" | |
35 | #endif | |
36 | #if (!(_WIN32) || (__CYGWIN__)) | |
37 | #include "../include/libnet.h" | |
38 | #else | |
39 | #include "../include/win32/libnet.h" | |
40 | #endif | |
41 | ||
42 | libnet_ptag_t | |
43 | libnet_build_mpls(u_int32_t label, u_int8_t experimental, u_int8_t bos, | |
44 | u_int8_t ttl, u_int8_t *payload, u_int32_t payload_s, libnet_t *l, | |
45 | libnet_ptag_t ptag) | |
46 | { | |
47 | u_int32_t n, h; | |
48 | libnet_pblock_t *p; | |
49 | struct libnet_mpls_hdr mpls_hdr; | |
50 | ||
51 | if (l == NULL) | |
52 | { | |
53 | return (-1); | |
54 | } | |
55 | ||
56 | n = LIBNET_MPLS_H + payload_s; | |
57 | h = 0; | |
58 | ||
59 | /* | |
60 | * Find the existing protocol block if a ptag is specified, or create | |
61 | * a new one. | |
62 | */ | |
63 | p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_MPLS_H); | |
64 | if (p == NULL) | |
65 | { | |
66 | return (-1); | |
67 | } | |
68 | ||
69 | memset(&mpls_hdr, 0, sizeof(mpls_hdr)); | |
70 | mpls_hdr.mpls_les = htonl((((label & 0x000fffff) << 12) | | |
71 | ((experimental & 0x07) << 9) | | |
72 | ((bos & 0x01) << 8) | | |
73 | ((ttl & 0xff)))); | |
74 | ||
75 | n = libnet_pblock_append(l, p, (u_int8_t *)&mpls_hdr, LIBNET_MPLS_H); | |
76 | if (n == -1) | |
77 | { | |
78 | goto bad; | |
79 | } | |
80 | ||
81 | if ((payload && !payload_s) || (!payload && payload_s)) | |
82 | { | |
83 | snprintf(l->err_buf, LIBNET_ERRBUF_SIZE, | |
84 | "%s(): payload inconsistency\n", __func__); | |
85 | goto bad; | |
86 | } | |
87 | ||
88 | if (payload && payload_s) | |
89 | { | |
90 | n = libnet_pblock_append(l, p, payload, payload_s); | |
91 | if (n == -1) | |
92 | { | |
93 | goto bad; | |
94 | } | |
95 | } | |
96 | ||
97 | /* | |
98 | * The link offset is actually 4 bytes further into the header than | |
99 | * before (the MPLS header adds this 4 bytes). We need to update the | |
100 | * link offset pointer. XXX - should we set this here? | |
101 | * Probably not. We should make pblock_coalesce check the pblock type | |
102 | * and adjust accordingly. | |
103 | */ | |
104 | l->link_offset += 4; | |
105 | ||
106 | return (ptag ? ptag : libnet_pblock_update(l, p, h, LIBNET_PBLOCK_MPLS_H)); | |
107 | bad: | |
108 | libnet_pblock_delete(l, p); | |
109 | return (-1); | |
110 | } | |
111 | ||
112 | /* EOF */ |