1/*	$OpenBSD: print-enc.c,v 1.7 2002/02/19 19:39:40 millert Exp $	*/
2
3/*
4 * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that: (1) source code distributions
9 * retain the above copyright notice and this paragraph in its entirety, (2)
10 * distributions including binary code include the above copyright notice and
11 * this paragraph in its entirety in the documentation or other materials
12 * provided with the distribution, and (3) all advertising materials mentioning
13 * features or use of this software display the following acknowledgement:
14 * ``This product includes software developed by the University of California,
15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16 * the University nor the names of its contributors may be used to endorse
17 * or promote products derived from this software without specific prior
18 * written permission.
19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22 */
23
24/* \summary: OpenBSD IPsec encapsulation BPF layer printer */
25
26#ifdef HAVE_CONFIG_H
27#include <config.h>
28#endif
29
30#include "netdissect-stdinc.h"
31
32#define ND_LONGJMP_FROM_TCHECK
33#include "netdissect.h"
34#include "extract.h"
35#include "af.h"
36
37/* From $OpenBSD: if_enc.h,v 1.8 2001/06/25 05:14:00 angelos Exp $ */
38/*
39 * The authors of this code are John Ioannidis (ji@tla.org),
40 * Angelos D. Keromytis (kermit@csd.uch.gr) and
41 * Niels Provos (provos@physnet.uni-hamburg.de).
42 *
43 * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
44 * in November 1995.
45 *
46 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
47 * by Angelos D. Keromytis.
48 *
49 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
50 * and Niels Provos.
51 *
52 * Copyright (C) 1995, 1996, 1997, 1998 by John Ioannidis, Angelos D. Keromytis
53 * and Niels Provos.
54 * Copyright (c) 2001, Angelos D. Keromytis.
55 *
56 * Permission to use, copy, and modify this software with or without fee
57 * is hereby granted, provided that this entire notice is included in
58 * all copies of any software which is or includes a copy or
59 * modification of this software.
60 * You may use this code under the GNU public license if you so wish. Please
61 * contribute changes back to the authors under this freer than GPL license
62 * so that we may further the use of strong encryption without limitations to
63 * all.
64 *
65 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
66 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
67 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
68 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
69 * PURPOSE.
70 */
71
72#define ENC_HDRLEN	12
73
74/* From $OpenBSD: mbuf.h,v 1.56 2002/01/25 15:50:23 art Exp $	*/
75#define M_CONF		0x0400  /* packet was encrypted (ESP-transport) */
76#define M_AUTH		0x0800  /* packet was authenticated (AH) */
77
78struct enchdr {
79	nd_uint32_t af;
80	nd_uint32_t spi;
81	nd_uint32_t flags;
82};
83
84#define ENC_PRINT_TYPE(wh, xf, name) \
85	if ((wh) & (xf)) { \
86		ND_PRINT("%s%s", name, (wh) == (xf) ? "): " : ","); \
87		(wh) &= ~(xf); \
88	}
89
90/*
91 * Byte-swap a 32-bit number.
92 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
93 * big-endian platforms.)
94 */
95#define	SWAPLONG(y) \
96((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
97
98void
99enc_if_print(netdissect_options *ndo,
100             const struct pcap_pkthdr *h, const u_char *p)
101{
102	u_int length = h->len;
103	u_int af, flags;
104	const struct enchdr *hdr;
105
106	ndo->ndo_protocol = "enc";
107	ND_TCHECK_LEN(p, ENC_HDRLEN);
108	ndo->ndo_ll_hdr_len += ENC_HDRLEN;
109
110	hdr = (const struct enchdr *)p;
111	/*
112	 * The address family and flags fields are in the byte order
113	 * of the host that originally captured the traffic.
114	 *
115	 * To determine that, look at the address family.  It's 32-bit,
116	 * it is not likely ever to be > 65535 (I doubt there will
117	 * ever be > 65535 address families and, so far, AF_ values have
118	 * not been allocated very sparsely) so it should not have the
119	 * upper 16 bits set, and it is not likely ever to be AF_UNSPEC,
120	 * i.e. it's not likely ever to be 0, so if it's byte-swapped,
121	 * it should have at least one of the upper 16 bits set.
122	 *
123	 * So if any of the upper 16 bits are set, we assume it, and
124	 * the flags field, are byte-swapped.
125	 *
126	 * The SPI field is always in network byte order, i.e. big-
127	 * endian.
128	 */
129	UNALIGNED_MEMCPY(&af, &hdr->af, sizeof (af));
130	UNALIGNED_MEMCPY(&flags, &hdr->flags, sizeof (flags));
131	if ((af & 0xFFFF0000) != 0) {
132		af = SWAPLONG(af);
133		flags = SWAPLONG(flags);
134	}
135
136	if (flags == 0)
137		ND_PRINT("(unprotected): ");
138	else
139		ND_PRINT("(");
140	ENC_PRINT_TYPE(flags, M_AUTH, "authentic");
141	ENC_PRINT_TYPE(flags, M_CONF, "confidential");
142	/* ENC_PRINT_TYPE(flags, M_TUNNEL, "tunnel"); */
143	ND_PRINT("SPI 0x%08x: ", GET_BE_U_4(hdr->spi));
144
145	length -= ENC_HDRLEN;
146	p += ENC_HDRLEN;
147
148	switch (af) {
149	case BSD_AFNUM_INET:
150		ip_print(ndo, p, length);
151		break;
152	case BSD_AFNUM_INET6_BSD:
153	case BSD_AFNUM_INET6_FREEBSD:
154	case BSD_AFNUM_INET6_DARWIN:
155		ip6_print(ndo, p, length);
156		break;
157	}
158}
159