The Tcpdump Group git mirrors - tcpdump/blob - print-pktap.c

   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 #ifdef HAVE_CONFIG_H
  25 #include "config.h"
  26 #endif
  27
  28 #include <netdissect-stdinc.h>
  29
  30 #include "netdissect.h"
  31 #include "extract.h"
  32
  33 #ifdef DLT_PKTAP
  34
  35 /*
  36  * XXX - these are little-endian in the captures I've seen, but Apple
  37  * no longer make any big-endian machines (Macs use x86, iOS machines
  38  * use ARM and run it little-endian), so that might be by definition
  39  * or they might be host-endian.
  40  *
  41  * If a big-endian PKTAP file ever shows up, and it comes from a
  42  * big-endian machine, presumably these are host-endian, and we need
  43  * to just fetch the fields directly in tcpdump but byte-swap them
  44  * to host byte order in libpcap.
  45  */
  46 typedef struct pktap_header {
  47         uint32_t        pkt_len;        /* length of pktap header */
  48         uint32_t        pkt_rectype;    /* type of record */
  49         uint32_t        pkt_dlt;        /* DLT type of this packet */
  50         char            pkt_ifname[24]; /* interface name */
  51         uint32_t        pkt_flags;
  52         uint32_t        pkt_pfamily;    /* "protocol family" */
  53         uint32_t        pkt_llhdrlen;   /* link-layer header length? */
  54         uint32_t        pkt_lltrlrlen;  /* link-layer trailer length? */
  55         uint32_t        pkt_pid;        /* process ID */
  56         char            pkt_cmdname[20]; /* command name */
  57         uint32_t        pkt_svc_class;  /* "service class" */
  58         uint16_t        pkt_iftype;     /* "interface type" */
  59         uint16_t        pkt_ifunit;     /* unit number of interface? */
  60         uint32_t        pkt_epid;       /* "effective process ID" */
  61         char            pkt_ecmdname[20]; /* "effective command name" */
  62 } pktap_header_t;
  63
  64 /*
  65  * Record types.
  66  */
  67 #define PKT_REC_NONE    0       /* nothing follows the header */
  68 #define PKT_REC_PACKET  1       /* a packet follows the header */
  69
  70 static inline void
  71 pktap_header_print(netdissect_options *ndo, const u_char *bp, u_int length)
  72 {
  73         const pktap_header_t *hdr;
  74         uint32_t dlt, hdrlen;
  75
  76         hdr = (const pktap_header_t *)bp;
  77
  78         dlt = EXTRACT_LE_32BITS(&hdr->pkt_dlt);
  79         hdrlen = EXTRACT_LE_32BITS(&hdr->pkt_len);
  80         if (!ndo->ndo_qflag) {
  81                 ND_PRINT((ndo,", DLT %s (%d) len %d",
  82                           pcap_datalink_val_to_name(dlt), dlt, hdrlen));
  83         } else {
  84                 ND_PRINT((ndo,", %s", pcap_datalink_val_to_name(dlt)));
  85         }
  86
  87         ND_PRINT((ndo, ", length %u: ", length));
  88 }
  89
  90 /*
  91  * This is the top level routine of the printer.  'p' points
  92  * to the ether header of the packet, 'h->ts' is the timestamp,
  93  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
  94  * is the number of bytes actually captured.
  95  */
  96 u_int
  97 pktap_if_print(netdissect_options *ndo,
  98                const struct pcap_pkthdr *h, const u_char *p)
  99 {
 100         uint32_t dlt, hdrlen, rectype;
 101         u_int caplen = h->caplen;
 102         u_int length = h->len;
 103         if_printer printer;
 104         const pktap_header_t *hdr;
 105
 106         if (caplen < sizeof(pktap_header_t) || length < sizeof(pktap_header_t)) {
 107                 ND_PRINT((ndo, "[|pktap]"));
 108                 return (0);
 109         }
 110         hdr = (const pktap_header_t *)p;
 111         dlt = EXTRACT_LE_32BITS(&hdr->pkt_dlt);
 112         hdrlen = EXTRACT_LE_32BITS(&hdr->pkt_len);
 113         if (hdrlen < sizeof(pktap_header_t)) {
 114                 /*
 115                  * Claimed header length < structure length.
 116                  * XXX - does this just mean some fields aren't
 117                  * being supplied, or is it truly an error (i.e.,
 118                  * is the length supplied so that the header can
 119                  * be expanded in the future)?
 120                  */
 121                 ND_PRINT((ndo, "[|pktap]"));
 122                 return (0);
 123         }
 124         if (caplen < hdrlen || length < hdrlen) {
 125                 ND_PRINT((ndo, "[|pktap]"));
 126                 return (hdrlen);
 127         }
 128
 129         if (ndo->ndo_eflag)
 130                 pktap_header_print(ndo, p, length);
 131
 132         length -= hdrlen;
 133         caplen -= hdrlen;
 134         p += hdrlen;
 135
 136         rectype = EXTRACT_LE_32BITS(&hdr->pkt_rectype);
 137         switch (rectype) {
 138
 139         case PKT_REC_NONE:
 140                 ND_PRINT((ndo, "no data"));
 141                 break;
 142
 143         case PKT_REC_PACKET:
 144                 if ((printer = lookup_printer(dlt)) != NULL) {
 145                         hdrlen += printer(ndo, h, p);
 146                 } else {
 147                         if (!ndo->ndo_eflag)
 148                                 pktap_header_print(ndo, (const u_char *)hdr,
 149                                                 length + hdrlen);
 150
 151                         if (!ndo->ndo_suppress_default_print)
 152                                 ND_DEFAULTPRINT(p, caplen);
 153                 }
 154                 break;
 155         }
 156
 157         return (hdrlen);
 158 }
 159
 160 /*
 161  * Local Variables:
 162  * c-style: whitesmith
 163  * c-basic-offset: 8
 164  * End:
 165  */
 166
 167 #endif /* DLT_PKTAP */