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
22 /* \summary: BSD loopback device printer */
23
24 #ifdef HAVE_CONFIG_H
25 #include "config.h"
26 #endif
27
28 #include <netdissect-stdinc.h>
29
30 #include <string.h>
31
32 #include "netdissect.h"
33 #include "af.h"
34
35 /*
36 * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
37 * 32-bit integer that specifies the family, e.g. AF_INET.
38 *
39 * Note here that "host" refers to the host on which the packets were
40 * captured; that isn't necessarily *this* host.
41 *
42 * The OpenBSD DLT_LOOP packet header is the same, except that the integer
43 * is in network byte order.
44 */
45 #define NULL_HDRLEN 4
46
47 /*
48 * Byte-swap a 32-bit number.
49 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
50 * big-endian platforms.)
51 */
52 #define SWAPLONG(y) \
53 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
54
55 static inline void
null_hdr_print(netdissect_options * ndo,u_int family,u_int length)56 null_hdr_print(netdissect_options *ndo, u_int family, u_int length)
57 {
58 if (!ndo->ndo_qflag) {
59 ND_PRINT((ndo, "AF %s (%u)",
60 tok2str(bsd_af_values,"Unknown",family),family));
61 } else {
62 ND_PRINT((ndo, "%s",
63 tok2str(bsd_af_values,"Unknown AF %u",family)));
64 }
65
66 ND_PRINT((ndo, ", length %u: ", length));
67 }
68
69 /*
70 * This is the top level routine of the printer. 'p' points
71 * to the ether header of the packet, 'h->ts' is the timestamp,
72 * 'h->len' is the length of the packet off the wire, and 'h->caplen'
73 * is the number of bytes actually captured.
74 */
75 u_int
null_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)76 null_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
77 {
78 u_int length = h->len;
79 u_int caplen = h->caplen;
80 u_int family;
81
82 if (caplen < NULL_HDRLEN) {
83 ND_PRINT((ndo, "[|null]"));
84 return (NULL_HDRLEN);
85 }
86
87 memcpy((char *)&family, (const char *)p, sizeof(family));
88
89 /*
90 * This isn't necessarily in our host byte order; if this is
91 * a DLT_LOOP capture, it's in network byte order, and if
92 * this is a DLT_NULL capture from a machine with the opposite
93 * byte-order, it's in the opposite byte order from ours.
94 *
95 * If the upper 16 bits aren't all zero, assume it's byte-swapped.
96 */
97 if ((family & 0xFFFF0000) != 0)
98 family = SWAPLONG(family);
99
100 if (ndo->ndo_eflag)
101 null_hdr_print(ndo, family, length);
102
103 length -= NULL_HDRLEN;
104 caplen -= NULL_HDRLEN;
105 p += NULL_HDRLEN;
106
107 switch (family) {
108
109 case BSD_AFNUM_INET:
110 ip_print(ndo, p, length);
111 break;
112
113 case BSD_AFNUM_INET6_BSD:
114 case BSD_AFNUM_INET6_FREEBSD:
115 case BSD_AFNUM_INET6_DARWIN:
116 ip6_print(ndo, p, length);
117 break;
118
119 case BSD_AFNUM_ISO:
120 isoclns_print(ndo, p, length);
121 break;
122
123 case BSD_AFNUM_APPLETALK:
124 atalk_print(ndo, p, length);
125 break;
126
127 case BSD_AFNUM_IPX:
128 ipx_print(ndo, p, length);
129 break;
130
131 default:
132 /* unknown AF_ value */
133 if (!ndo->ndo_eflag)
134 null_hdr_print(ndo, family, length + NULL_HDRLEN);
135 if (!ndo->ndo_suppress_default_print)
136 ND_DEFAULTPRINT(p, caplen);
137 }
138
139 return (NULL_HDRLEN);
140 }
141
142 /*
143 * Local Variables:
144 * c-style: whitesmith
145 * c-basic-offset: 8
146 * End:
147 */
148