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Print truncations with nd_print_trunc() instead of tstr[] strings
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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 "extract.h"
34 #include "af.h"
35
36
37 /*
38 * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
39 * 32-bit integer that specifies the family, e.g. AF_INET.
40 *
41 * Note here that "host" refers to the host on which the packets were
42 * captured; that isn't necessarily *this* host.
43 *
44 * The OpenBSD DLT_LOOP packet header is the same, except that the integer
45 * is in network byte order.
46 */
47 #define NULL_HDRLEN 4
48
49 /*
50 * Byte-swap a 32-bit number.
51 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
52 * big-endian platforms.)
53 */
54 #define SWAPLONG(y) \
55 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
56
57 static void
58 null_hdr_print(netdissect_options *ndo, u_int family, u_int length)
59 {
60 if (!ndo->ndo_qflag) {
61 ND_PRINT("AF %s (%u)",
62 tok2str(bsd_af_values,"Unknown",family),family);
63 } else {
64 ND_PRINT("%s",
65 tok2str(bsd_af_values,"Unknown AF %u",family));
66 }
67
68 ND_PRINT(", length %u: ", length);
69 }
70
71 /*
72 * This is the top level routine of the printer. 'p' points
73 * to the ether header of the packet, 'h->ts' is the timestamp,
74 * 'h->len' is the length of the packet off the wire, and 'h->caplen'
75 * is the number of bytes actually captured.
76 */
77 u_int
78 null_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
79 {
80 u_int length = h->len;
81 u_int caplen = h->caplen;
82 uint32_t family;
83
84 ndo->ndo_protocol = "null_if";
85 if (caplen < NULL_HDRLEN)
86 goto trunc;
87
88 ND_TCHECK_4(p);
89 memcpy((char *)&family, (const char *)p, sizeof(family));
90
91 /*
92 * This isn't necessarily in our host byte order; if this is
93 * a DLT_LOOP capture, it's in network byte order, and if
94 * this is a DLT_NULL capture from a machine with the opposite
95 * byte-order, it's in the opposite byte order from ours.
96 *
97 * If the upper 16 bits aren't all zero, assume it's byte-swapped.
98 */
99 if ((family & 0xFFFF0000) != 0)
100 family = SWAPLONG(family);
101
102 if (ndo->ndo_eflag)
103 null_hdr_print(ndo, family, length);
104
105 length -= NULL_HDRLEN;
106 caplen -= NULL_HDRLEN;
107 p += NULL_HDRLEN;
108
109 switch (family) {
110
111 case BSD_AFNUM_INET:
112 ip_print(ndo, p, length);
113 break;
114
115 case BSD_AFNUM_INET6_BSD:
116 case BSD_AFNUM_INET6_FREEBSD:
117 case BSD_AFNUM_INET6_DARWIN:
118 ip6_print(ndo, p, length);
119 break;
120
121 case BSD_AFNUM_ISO:
122 isoclns_print(ndo, p, length);
123 break;
124
125 case BSD_AFNUM_APPLETALK:
126 atalk_print(ndo, p, length);
127 break;
128
129 case BSD_AFNUM_IPX:
130 ipx_print(ndo, p, length);
131 break;
132
133 default:
134 /* unknown AF_ value */
135 if (!ndo->ndo_eflag)
136 null_hdr_print(ndo, family, length + NULL_HDRLEN);
137 if (!ndo->ndo_suppress_default_print)
138 ND_DEFAULTPRINT(p, caplen);
139 }
140
141 return (NULL_HDRLEN);
142 trunc:
143 nd_print_trunc(ndo);
144 return (NULL_HDRLEN);
145 }