1/*	$OpenBSD: mpls_shim.c,v 1.8 2014/12/05 15:50:04 mpi Exp $	*/
2
3/*
4 * Copyright (C) 1999, 2000 and 2001 AYAME Project, WIDE Project.
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 *
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include <sys/param.h>
34#include <sys/mbuf.h>
35#include <sys/errno.h>
36#include <sys/socket.h>
37#include <sys/systm.h>
38
39#include <net/if.h>
40#include <net/if_var.h>
41
42#include <netmpls/mpls.h>
43
44struct mbuf *
45mpls_shim_pop(struct mbuf *m)
46{
47	/* shaves off top shim header from mbuf */
48	m_adj(m, sizeof(struct shim_hdr));
49
50	/* catch-up next shim_hdr */
51	if (m->m_len < sizeof(struct shim_hdr))
52		if ((m = m_pullup(m, sizeof(struct shim_hdr))) == NULL)
53			return (NULL);
54
55	/* return mbuf */
56	return (m);
57}
58
59struct mbuf *
60mpls_shim_swap(struct mbuf *m, struct rt_mpls *rt_mpls)
61{
62	struct shim_hdr *shim;
63
64	/* pullup shim_hdr */
65	if (m->m_len < sizeof(struct shim_hdr))
66		if ((m = m_pullup(m, sizeof(struct shim_hdr))) == NULL)
67			return (NULL);
68	shim = mtod(m, struct shim_hdr *);
69
70	/* swap label */
71	shim->shim_label &= ~MPLS_LABEL_MASK;
72	shim->shim_label |= rt_mpls->mpls_label & MPLS_LABEL_MASK;
73
74	/* swap exp : XXX exp override */
75	{
76		u_int32_t	t;
77
78		shim->shim_label &= ~MPLS_EXP_MASK;
79		t = rt_mpls->mpls_exp << MPLS_EXP_OFFSET;
80		shim->shim_label |= htonl(t) & MPLS_EXP_MASK;
81	}
82
83	return (m);
84}
85
86struct mbuf *
87mpls_shim_push(struct mbuf *m, struct rt_mpls *rt_mpls)
88{
89	struct shim_hdr *shim;
90
91	M_PREPEND(m, sizeof(struct shim_hdr), M_DONTWAIT);
92	if (m == NULL)
93		return (NULL);
94
95	shim = mtod(m, struct shim_hdr *);
96	bzero((caddr_t)shim, sizeof(*shim));
97
98	return (mpls_shim_swap(m, rt_mpls));
99}
100