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#include <sys/cdefs.h>
25#ifndef lint
26__RCSID("$NetBSD: print-enc.c,v 1.8 2023/08/17 20:19:40 christos Exp $");
27#endif
28
29/* \summary: OpenBSD IPsec encapsulation BPF layer printer */
30
31#ifdef HAVE_CONFIG_H
32#include <config.h>
33#endif
34
35#include "netdissect-stdinc.h"
36
37#define ND_LONGJMP_FROM_TCHECK
38#include "netdissect.h"
39#include "extract.h"
40#include "af.h"
41
42/* From $OpenBSD: if_enc.h,v 1.8 2001/06/25 05:14:00 angelos Exp $ */
43/*
44 * The authors of this code are John Ioannidis (ji@tla.org),
45 * Angelos D. Keromytis (kermit@csd.uch.gr) and
46 * Niels Provos (provos@physnet.uni-hamburg.de).
47 *
48 * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
49 * in November 1995.
50 *
51 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
52 * by Angelos D. Keromytis.
53 *
54 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
55 * and Niels Provos.
56 *
57 * Copyright (C) 1995, 1996, 1997, 1998 by John Ioannidis, Angelos D. Keromytis
58 * and Niels Provos.
59 * Copyright (c) 2001, Angelos D. Keromytis.
60 *
61 * Permission to use, copy, and modify this software with or without fee
62 * is hereby granted, provided that this entire notice is included in
63 * all copies of any software which is or includes a copy or
64 * modification of this software.
65 * You may use this code under the GNU public license if you so wish. Please
66 * contribute changes back to the authors under this freer than GPL license
67 * so that we may further the use of strong encryption without limitations to
68 * all.
69 *
70 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
71 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
72 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
73 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
74 * PURPOSE.
75 */
76
77#define ENC_HDRLEN	12
78
79/* From $OpenBSD: mbuf.h,v 1.56 2002/01/25 15:50:23 art Exp $	*/
80#define M_CONF		0x0400  /* packet was encrypted (ESP-transport) */
81#define M_AUTH		0x0800  /* packet was authenticated (AH) */
82
83struct enchdr {
84	nd_uint32_t af;
85	nd_uint32_t spi;
86	nd_uint32_t flags;
87};
88
89#define ENC_PRINT_TYPE(wh, xf, name) \
90	if ((wh) & (xf)) { \
91		ND_PRINT("%s%s", name, (wh) == (xf) ? "): " : ","); \
92		(wh) &= ~(xf); \
93	}
94
95/*
96 * Byte-swap a 32-bit number.
97 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
98 * big-endian platforms.)
99 */
100#define	SWAPLONG(y) \
101((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
102
103void
104enc_if_print(netdissect_options *ndo,
105             const struct pcap_pkthdr *h, const u_char *p)
106{
107	u_int length = h->len;
108	u_int af, flags;
109	const struct enchdr *hdr;
110
111	ndo->ndo_protocol = "enc";
112	ND_TCHECK_LEN(p, ENC_HDRLEN);
113	ndo->ndo_ll_hdr_len += ENC_HDRLEN;
114
115	hdr = (const struct enchdr *)p;
116	/*
117	 * The address family and flags fields are in the byte order
118	 * of the host that originally captured the traffic.
119	 *
120	 * To determine that, look at the address family.  It's 32-bit,
121	 * it is not likely ever to be > 65535 (I doubt there will
122	 * ever be > 65535 address families and, so far, AF_ values have
123	 * not been allocated very sparsely) so it should not have the
124	 * upper 16 bits set, and it is not likely ever to be AF_UNSPEC,
125	 * i.e. it's not likely ever to be 0, so if it's byte-swapped,
126	 * it should have at least one of the upper 16 bits set.
127	 *
128	 * So if any of the upper 16 bits are set, we assume it, and
129	 * the flags field, are byte-swapped.
130	 *
131	 * The SPI field is always in network byte order, i.e. big-
132	 * endian.
133	 */
134	UNALIGNED_MEMCPY(&af, &hdr->af, sizeof (af));
135	UNALIGNED_MEMCPY(&flags, &hdr->flags, sizeof (flags));
136	if ((af & 0xFFFF0000) != 0) {
137		af = SWAPLONG(af);
138		flags = SWAPLONG(flags);
139	}
140
141	if (flags == 0)
142		ND_PRINT("(unprotected): ");
143	else
144		ND_PRINT("(");
145	ENC_PRINT_TYPE(flags, M_AUTH, "authentic");
146	ENC_PRINT_TYPE(flags, M_CONF, "confidential");
147	/* ENC_PRINT_TYPE(flags, M_TUNNEL, "tunnel"); */
148	ND_PRINT("SPI 0x%08x: ", GET_BE_U_4(hdr->spi));
149
150	length -= ENC_HDRLEN;
151	p += ENC_HDRLEN;
152
153	switch (af) {
154	case BSD_AFNUM_INET:
155		ip_print(ndo, p, length);
156		break;
157	case BSD_AFNUM_INET6_BSD:
158	case BSD_AFNUM_INET6_FREEBSD:
159	case BSD_AFNUM_INET6_DARWIN:
160		ip6_print(ndo, p, length);
161		break;
162	}
163}
164