1 /*
2 * Copyright (c) 1991, 1993, 1994, 1995, 1996, 1997
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
16 * written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 *
21 * $FreeBSD$
22 */
23
24 #define NETDISSECT_REWORKED
25 #ifdef HAVE_CONFIG_H
26 #include "config.h"
27 #endif
28
29 #include <tcpdump-stdinc.h>
30
31 #include <string.h>
32
33 #include "interface.h"
34 #include "af.h"
35
36 /*
37 * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
38 * 32-bit integer that specifies the family, e.g. AF_INET.
39 *
40 * Note here that "host" refers to the host on which the packets were
41 * captured; that isn't necessarily *this* host.
42 *
43 * The OpenBSD DLT_LOOP packet header is the same, except that the integer
44 * is in network byte order.
45 */
46 #define NULL_HDRLEN 4
47
48 /*
49 * Byte-swap a 32-bit number.
50 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
51 * big-endian platforms.)
52 */
53 #define SWAPLONG(y) \
54 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
55
56 static inline void
null_hdr_print(netdissect_options * ndo,u_int family,u_int length)57 null_hdr_print(netdissect_options *ndo, u_int family, u_int length)
58 {
59 if (!ndo->ndo_qflag) {
60 ND_PRINT((ndo, "AF %s (%u)",
61 tok2str(bsd_af_values,"Unknown",family),family));
62 } else {
63 ND_PRINT((ndo, "%s",
64 tok2str(bsd_af_values,"Unknown AF %u",family)));
65 }
66
67 ND_PRINT((ndo, ", length %u: ", length));
68 }
69
70 /*
71 * This is the top level routine of the printer. 'p' points
72 * to the ether header of the packet, 'h->ts' is the timestamp,
73 * 'h->len' is the length of the packet off the wire, and 'h->caplen'
74 * is the number of bytes actually captured.
75 */
76 u_int
null_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)77 null_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
78 {
79 u_int length = h->len;
80 u_int caplen = h->caplen;
81 u_int family;
82
83 if (caplen < NULL_HDRLEN) {
84 ND_PRINT((ndo, "[|null]"));
85 return (NULL_HDRLEN);
86 }
87
88 memcpy((char *)&family, (char *)p, sizeof(family));
89
90 /*
91 * This isn't necessarily in our host byte order; if this is
92 * a DLT_LOOP capture, it's in network byte order, and if
93 * this is a DLT_NULL capture from a machine with the opposite
94 * byte-order, it's in the opposite byte order from ours.
95 *
96 * If the upper 16 bits aren't all zero, assume it's byte-swapped.
97 */
98 if ((family & 0xFFFF0000) != 0)
99 family = SWAPLONG(family);
100
101 if (ndo->ndo_eflag)
102 null_hdr_print(ndo, family, length);
103
104 length -= NULL_HDRLEN;
105 caplen -= NULL_HDRLEN;
106 p += NULL_HDRLEN;
107
108 switch (family) {
109
110 case BSD_AFNUM_INET:
111 ip_print(ndo, p, length);
112 break;
113
114 case BSD_AFNUM_INET6_BSD:
115 case BSD_AFNUM_INET6_FREEBSD:
116 case BSD_AFNUM_INET6_DARWIN:
117 ip6_print(ndo, p, length);
118 break;
119
120 case BSD_AFNUM_ISO:
121 isoclns_print(ndo, p, length, caplen);
122 break;
123
124 case BSD_AFNUM_APPLETALK:
125 atalk_print(ndo, p, length);
126 break;
127
128 case BSD_AFNUM_IPX:
129 ipx_print(ndo, p, length);
130 break;
131
132 default:
133 /* unknown AF_ value */
134 if (!ndo->ndo_eflag)
135 null_hdr_print(ndo, family, length + NULL_HDRLEN);
136 if (!ndo->ndo_suppress_default_print)
137 ND_DEFAULTPRINT(p, caplen);
138 }
139
140 return (NULL_HDRLEN);
141 }
142
143 /*
144 * Local Variables:
145 * c-style: whitesmith
146 * c-basic-offset: 8
147 * End:
148 */
149