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-rw-r--r--print-null.c138
1 files changed, 138 insertions, 0 deletions
diff --git a/print-null.c b/print-null.c
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--- /dev/null
+++ b/print-null.c
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+/*
+ * Copyright (c) 1991, 1993, 1994, 1995, 1996, 1997
+ * 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: BSD loopback device 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"
+
+
+/*
+ * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
+ * 32-bit integer that specifies the family, e.g. AF_INET.
+ *
+ * Note here that "host" refers to the host on which the packets were
+ * captured; that isn't necessarily *this* host.
+ *
+ * The OpenBSD DLT_LOOP packet header is the same, except that the integer
+ * is in network byte order.
+ */
+#define NULL_HDRLEN 4
+
+/*
+ * 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))
+
+static void
+null_hdr_print(netdissect_options *ndo, uint32_t family, u_int length)
+{
+ if (!ndo->ndo_qflag) {
+ ND_PRINT("AF %s (%u)",
+ tok2str(bsd_af_values,"Unknown",family),family);
+ } else {
+ ND_PRINT("%s",
+ tok2str(bsd_af_values,"Unknown AF %u",family));
+ }
+
+ ND_PRINT(", length %u: ", length);
+}
+
+/*
+ * This is the top level routine of the printer. 'p' points
+ * to the ether header of the packet, 'h->ts' is the timestamp,
+ * 'h->len' is the length of the packet off the wire, and 'h->caplen'
+ * is the number of bytes actually captured.
+ */
+void
+null_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
+{
+ u_int length = h->len;
+ u_int caplen = h->caplen;
+ uint32_t family;
+
+ ndo->ndo_protocol = "null";
+ ND_TCHECK_LEN(p, NULL_HDRLEN);
+ ndo->ndo_ll_hdr_len += NULL_HDRLEN;
+
+ family = GET_HE_U_4(p);
+
+ /*
+ * This isn't necessarily in our host byte order; if this is
+ * a DLT_LOOP capture, it's in network byte order, and if
+ * this is a DLT_NULL capture from a machine with the opposite
+ * byte-order, it's in the opposite byte order from ours.
+ *
+ * If the upper 16 bits aren't all zero, assume it's byte-swapped.
+ */
+ if ((family & 0xFFFF0000) != 0)
+ family = SWAPLONG(family);
+
+ if (ndo->ndo_eflag)
+ null_hdr_print(ndo, family, length);
+
+ length -= NULL_HDRLEN;
+ caplen -= NULL_HDRLEN;
+ p += NULL_HDRLEN;
+
+ switch (family) {
+
+ 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;
+
+ case BSD_AFNUM_ISO:
+ isoclns_print(ndo, p, length);
+ break;
+
+ case BSD_AFNUM_APPLETALK:
+ atalk_print(ndo, p, length);
+ break;
+
+ case BSD_AFNUM_IPX:
+ ipx_print(ndo, p, length);
+ break;
+
+ default:
+ /* unknown AF_ value */
+ if (!ndo->ndo_eflag)
+ null_hdr_print(ndo, family, length + NULL_HDRLEN);
+ if (!ndo->ndo_suppress_default_print)
+ ND_DEFAULTPRINT(p, caplen);
+ }
+}