1 /*
2 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
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: Apple's DLT_PKTAP printer */
23
24 #include <config.h>
25
26 #include "netdissect-stdinc.h"
27
28 #define ND_LONGJMP_FROM_TCHECK
29 #include "netdissect.h"
30 #include "extract.h"
31
32 #ifdef DLT_PKTAP
33
34 /*
35 * XXX - these are little-endian in the captures I've seen, but Apple
36 * no longer make any big-endian machines (Macs use x86, iOS machines
37 * use ARM and run it little-endian), so that might be by definition
38 * or they might be host-endian.
39 *
40 * If a big-endian PKTAP file ever shows up, and it comes from a
41 * big-endian machine, presumably these are host-endian, and we need
42 * to just fetch the fields directly in tcpdump but byte-swap them
43 * to host byte order in libpcap.
44 */
45 typedef struct pktap_header {
46 nd_uint32_t pkt_len; /* length of pktap header */
47 nd_uint32_t pkt_rectype; /* type of record */
48 nd_uint32_t pkt_dlt; /* DLT type of this packet */
49 char pkt_ifname[24]; /* interface name */
50 nd_uint32_t pkt_flags;
51 nd_uint32_t pkt_pfamily; /* "protocol family" */
52 nd_uint32_t pkt_llhdrlen; /* link-layer header length? */
53 nd_uint32_t pkt_lltrlrlen; /* link-layer trailer length? */
54 nd_uint32_t pkt_pid; /* process ID */
55 char pkt_cmdname[20]; /* command name */
56 nd_uint32_t pkt_svc_class; /* "service class" */
57 nd_uint16_t pkt_iftype; /* "interface type" */
58 nd_uint16_t pkt_ifunit; /* unit number of interface? */
59 nd_uint32_t pkt_epid; /* "effective process ID" */
60 char pkt_ecmdname[20]; /* "effective command name" */
61 } pktap_header_t;
62
63 /*
64 * Record types.
65 */
66 #define PKT_REC_NONE 0 /* nothing follows the header */
67 #define PKT_REC_PACKET 1 /* a packet follows the header */
68
69 static void
pktap_header_print(netdissect_options * ndo,const u_char * bp,u_int length)70 pktap_header_print(netdissect_options *ndo, const u_char *bp, u_int length)
71 {
72 const pktap_header_t *hdr;
73 uint32_t dlt, hdrlen;
74 const char *dltname;
75
76 hdr = (const pktap_header_t *)bp;
77
78 dlt = GET_LE_U_4(hdr->pkt_dlt);
79 hdrlen = GET_LE_U_4(hdr->pkt_len);
80 dltname = pcap_datalink_val_to_name(dlt);
81 if (!ndo->ndo_qflag) {
82 ND_PRINT("DLT %s (%u) len %u",
83 (dltname != NULL ? dltname : "UNKNOWN"), dlt, hdrlen);
84 } else {
85 ND_PRINT("%s", (dltname != NULL ? dltname : "UNKNOWN"));
86 }
87
88 ND_PRINT(", length %u: ", length);
89 }
90
91 /*
92 * This is the top level routine of the printer. 'p' points
93 * to the ether header of the packet, 'h->ts' is the timestamp,
94 * 'h->len' is the length of the packet off the wire, and 'h->caplen'
95 * is the number of bytes actually captured.
96 */
97 void
pktap_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)98 pktap_if_print(netdissect_options *ndo,
99 const struct pcap_pkthdr *h, const u_char *p)
100 {
101 uint32_t dlt, hdrlen, rectype;
102 u_int caplen = h->caplen;
103 u_int length = h->len;
104 if_printer printer;
105 const pktap_header_t *hdr;
106 struct pcap_pkthdr nhdr;
107
108 ndo->ndo_protocol = "pktap";
109 if (length < sizeof(pktap_header_t)) {
110 ND_PRINT(" (packet too short, %u < %zu)",
111 length, sizeof(pktap_header_t));
112 goto invalid;
113 }
114 hdr = (const pktap_header_t *)p;
115 dlt = GET_LE_U_4(hdr->pkt_dlt);
116 hdrlen = GET_LE_U_4(hdr->pkt_len);
117 if (hdrlen < sizeof(pktap_header_t)) {
118 /*
119 * Claimed header length < structure length.
120 * XXX - does this just mean some fields aren't
121 * being supplied, or is it truly an error (i.e.,
122 * is the length supplied so that the header can
123 * be expanded in the future)?
124 */
125 ND_PRINT(" (pkt_len too small, %u < %zu)",
126 hdrlen, sizeof(pktap_header_t));
127 goto invalid;
128 }
129 if (hdrlen > length) {
130 ND_PRINT(" (pkt_len too big, %u > %u)",
131 hdrlen, length);
132 goto invalid;
133 }
134 ND_TCHECK_LEN(p, hdrlen);
135
136 if (ndo->ndo_eflag)
137 pktap_header_print(ndo, p, length);
138
139 length -= hdrlen;
140 caplen -= hdrlen;
141 p += hdrlen;
142
143 rectype = GET_LE_U_4(hdr->pkt_rectype);
144 switch (rectype) {
145
146 case PKT_REC_NONE:
147 ND_PRINT("no data");
148 break;
149
150 case PKT_REC_PACKET:
151 printer = lookup_printer(dlt);
152 if (printer != NULL) {
153 nhdr = *h;
154 nhdr.caplen = caplen;
155 nhdr.len = length;
156 printer(ndo, &nhdr, p);
157 hdrlen += ndo->ndo_ll_hdr_len;
158 } else {
159 if (!ndo->ndo_eflag)
160 pktap_header_print(ndo, (const u_char *)hdr,
161 length + hdrlen);
162
163 if (!ndo->ndo_suppress_default_print)
164 ND_DEFAULTPRINT(p, caplen);
165 }
166 break;
167 }
168
169 ndo->ndo_ll_hdr_len += hdrlen;
170 return;
171
172 invalid:
173 nd_print_invalid(ndo);
174 }
175 #endif /* DLT_PKTAP */
176