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