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 #define NETDISSECT_REWORKED
  23 #ifdef HAVE_CONFIG_H
  24 #include "config.h"
  25 #endif
  26
  27 #include <tcpdump-stdinc.h>
  28
  29 #include "interface.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         uint32_t        pkt_len;        /* length of pktap header */
  47         uint32_t        pkt_rectype;    /* type of record */
  48         uint32_t        pkt_dlt;        /* DLT type of this packet */
  49         char            pkt_ifname[24]; /* interface name */
  50         uint32_t        pkt_flags;
  51         uint32_t        pkt_pfamily;    /* "protocol family" */
  52         uint32_t        pkt_llhdrlen;   /* link-layer header length? */
  53         uint32_t        pkt_lltrlrlen;  /* link-layer trailer length? */
  54         uint32_t        pkt_pid;        /* process ID */
  55         char            pkt_cmdname[20]; /* command name */
  56         uint32_t        pkt_svc_class;  /* "service class" */
  57         uint16_t        pkt_iftype;     /* "interface type" */
  58         uint16_t        pkt_ifunit;     /* unit number of interface? */
  59         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 inline void
  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
  75         hdr = (const pktap_header_t *)bp;
  76
  77         dlt = EXTRACT_LE_32BITS(&hdr->pkt_dlt);
  78         hdrlen = EXTRACT_LE_32BITS(&hdr->pkt_len);
  79         if (!ndo->ndo_qflag) {
  80                 ND_PRINT((ndo,", DLT %s (%d) len %d",
  81                           pcap_datalink_val_to_name(dlt), dlt, hdrlen));
  82         } else {
  83                 ND_PRINT((ndo,", %s", pcap_datalink_val_to_name(dlt)));
  84         }
  85
  86         ND_PRINT((ndo, ", length %u: ", length));
  87 }
  88
  89 /*
  90  * This is the top level routine of the printer.  'p' points
  91  * to the ether header of the packet, 'h->ts' is the timestamp,
  92  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
  93  * is the number of bytes actually captured.
  94  */
  95 u_int
  96 pktap_if_print(netdissect_options *ndo,
  97                const struct pcap_pkthdr *h, const u_char *p)
  98 {
  99         uint32_t dlt, hdrlen, rectype;
 100         u_int caplen = h->caplen;
 101         u_int length = h->len;
 102         if_printer printer;
 103         pktap_header_t *hdr;
 104
 105         if (caplen < sizeof(pktap_header_t) || length < sizeof(pktap_header_t)) {
 106                 ND_PRINT((ndo, "[|pktap]"));
 107                 return (0);
 108         }
 109         hdr = (pktap_header_t *)p;
 110         dlt = EXTRACT_LE_32BITS(&hdr->pkt_dlt);
 111         hdrlen = EXTRACT_LE_32BITS(&hdr->pkt_len);
 112         if (hdrlen < sizeof(pktap_header_t)) {
 113                 /*
 114                  * Claimed header length < structure length.
 115                  * XXX - does this just mean some fields aren't
 116                  * being supplied, or is it truly an error (i.e.,
 117                  * is the length supplied so that the header can
 118                  * be expanded in the future)?
 119                  */
 120                 ND_PRINT((ndo, "[|pktap]"));
 121                 return (0);
 122         }
 123         if (caplen < hdrlen || length < hdrlen) {
 124                 ND_PRINT((ndo, "[|pktap]"));
 125                 return (hdrlen);
 126         }
 127
 128         if (ndo->ndo_eflag)
 129                 pktap_header_print(ndo, p, length);
 130
 131         length -= hdrlen;
 132         caplen -= hdrlen;
 133         p += hdrlen;
 134
 135         rectype = EXTRACT_LE_32BITS(&hdr->pkt_rectype);
 136         switch (rectype) {
 137
 138         case PKT_REC_NONE:
 139                 ND_PRINT((ndo, "no data"));
 140                 break;
 141
 142         case PKT_REC_PACKET:
 143                 if ((printer = lookup_printer(dlt)) != NULL) {
 144                         printer(ndo, h, p);
 145                 } else {
 146                         if (!ndo->ndo_eflag)
 147                                 pktap_header_print(ndo, (u_char *)hdr,
 148                                                 length + hdrlen);
 149
 150                         if (!ndo->ndo_suppress_default_print)
 151                                 ND_DEFAULTPRINT(p, caplen);
 152                 }
 153                 break;
 154         }
 155
 156         return (hdrlen);
 157 }
 158
 159 /*
 160  * Local Variables:
 161  * c-style: whitesmith
 162  * c-basic-offset: 8
 163  * End:
 164  */
 165
 166 #endif /* DLT_PKTAP */