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+/* $OpenBSD: print-enc.c,v 1.7 2002/02/19 19:39:40 millert Exp $ */
+
+/*
+ * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that: (1) source code distributions
+ * retain the above copyright notice and this paragraph in its entirety, (2)
+ * distributions including binary code include the above copyright notice and
+ * this paragraph in its entirety in the documentation or other materials
+ * provided with the distribution, and (3) all advertising materials mentioning
+ * features or use of this software display the following acknowledgement:
+ * ``This product includes software developed by the University of California,
+ * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
+ * the University nor the names of its contributors may be used to endorse
+ * or promote products derived from this software without specific prior
+ * written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+/* \summary: OpenBSD IPsec encapsulation BPF layer printer */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "netdissect-stdinc.h"
+
+#define ND_LONGJMP_FROM_TCHECK
+#include "netdissect.h"
+#include "extract.h"
+#include "af.h"
+
+/* From $OpenBSD: if_enc.h,v 1.8 2001/06/25 05:14:00 angelos Exp $ */
+/*
+ * The authors of this code are John Ioannidis (ji@tla.org),
+ * Angelos D. Keromytis (kermit@csd.uch.gr) and
+ * Niels Provos (provos@physnet.uni-hamburg.de).
+ *
+ * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
+ * in November 1995.
+ *
+ * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
+ * by Angelos D. Keromytis.
+ *
+ * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
+ * and Niels Provos.
+ *
+ * Copyright (C) 1995, 1996, 1997, 1998 by John Ioannidis, Angelos D. Keromytis
+ * and Niels Provos.
+ * Copyright (c) 2001, Angelos D. Keromytis.
+ *
+ * Permission to use, copy, and modify this software with or without fee
+ * is hereby granted, provided that this entire notice is included in
+ * all copies of any software which is or includes a copy or
+ * modification of this software.
+ * You may use this code under the GNU public license if you so wish. Please
+ * contribute changes back to the authors under this freer than GPL license
+ * so that we may further the use of strong encryption without limitations to
+ * all.
+ *
+ * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
+ * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
+ * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
+ * PURPOSE.
+ */
+
+#define ENC_HDRLEN 12
+
+/* From $OpenBSD: mbuf.h,v 1.56 2002/01/25 15:50:23 art Exp $ */
+#define M_CONF 0x0400 /* packet was encrypted (ESP-transport) */
+#define M_AUTH 0x0800 /* packet was authenticated (AH) */
+
+struct enchdr {
+ nd_uint32_t af;
+ nd_uint32_t spi;
+ nd_uint32_t flags;
+};
+
+#define ENC_PRINT_TYPE(wh, xf, name) \
+ if ((wh) & (xf)) { \
+ ND_PRINT("%s%s", name, (wh) == (xf) ? "): " : ","); \
+ (wh) &= ~(xf); \
+ }
+
+/*
+ * Byte-swap a 32-bit number.
+ * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
+ * big-endian platforms.)
+ */
+#define SWAPLONG(y) \
+((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
+
+void
+enc_if_print(netdissect_options *ndo,
+ const struct pcap_pkthdr *h, const u_char *p)
+{
+ u_int length = h->len;
+ u_int af, flags;
+ const struct enchdr *hdr;
+
+ ndo->ndo_protocol = "enc";
+ ND_TCHECK_LEN(p, ENC_HDRLEN);
+ ndo->ndo_ll_hdr_len += ENC_HDRLEN;
+
+ hdr = (const struct enchdr *)p;
+ /*
+ * The address family and flags fields are in the byte order
+ * of the host that originally captured the traffic.
+ *
+ * To determine that, look at the address family. It's 32-bit,
+ * it is not likely ever to be > 65535 (I doubt there will
+ * ever be > 65535 address families and, so far, AF_ values have
+ * not been allocated very sparsely) so it should not have the
+ * upper 16 bits set, and it is not likely ever to be AF_UNSPEC,
+ * i.e. it's not likely ever to be 0, so if it's byte-swapped,
+ * it should have at least one of the upper 16 bits set.
+ *
+ * So if any of the upper 16 bits are set, we assume it, and
+ * the flags field, are byte-swapped.
+ *
+ * The SPI field is always in network byte order, i.e. big-
+ * endian.
+ */
+ UNALIGNED_MEMCPY(&af, &hdr->af, sizeof (af));
+ UNALIGNED_MEMCPY(&flags, &hdr->flags, sizeof (flags));
+ if ((af & 0xFFFF0000) != 0) {
+ af = SWAPLONG(af);
+ flags = SWAPLONG(flags);
+ }
+
+ if (flags == 0)
+ ND_PRINT("(unprotected): ");
+ else
+ ND_PRINT("(");
+ ENC_PRINT_TYPE(flags, M_AUTH, "authentic");
+ ENC_PRINT_TYPE(flags, M_CONF, "confidential");
+ /* ENC_PRINT_TYPE(flags, M_TUNNEL, "tunnel"); */
+ ND_PRINT("SPI 0x%08x: ", GET_BE_U_4(hdr->spi));
+
+ length -= ENC_HDRLEN;
+ p += ENC_HDRLEN;
+
+ switch (af) {
+ case BSD_AFNUM_INET:
+ ip_print(ndo, p, length);
+ break;
+ case BSD_AFNUM_INET6_BSD:
+ case BSD_AFNUM_INET6_FREEBSD:
+ case BSD_AFNUM_INET6_DARWIN:
+ ip6_print(ndo, p, length);
+ break;
+ }
+}