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         nd_uint32_t     pkt_len;        /* length of pktap header */
  48         nd_uint32_t     pkt_rectype;    /* type of record */
  49         nd_uint32_t     pkt_dlt;        /* DLT type of this packet */
  50         char            pkt_ifname[24]; /* interface name */
  51         nd_uint32_t     pkt_flags;
  52         nd_uint32_t     pkt_pfamily;    /* "protocol family" */
  53         nd_uint32_t     pkt_llhdrlen;   /* link-layer header length? */
  54         nd_uint32_t     pkt_lltrlrlen;  /* link-layer trailer length? */
  55         nd_uint32_t     pkt_pid;        /* process ID */
  56         char            pkt_cmdname[20]; /* command name */
  57         nd_uint32_t     pkt_svc_class;  /* "service class" */
  58         nd_uint16_t     pkt_iftype;     /* "interface type" */
  59         nd_uint16_t     pkt_ifunit;     /* unit number of interface? */
  60         nd_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 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         const char *dltname;
  76
  77         hdr = (const pktap_header_t *)bp;
  78
  79         dlt = EXTRACT_LE_U_4(hdr->pkt_dlt);
  80         hdrlen = EXTRACT_LE_U_4(hdr->pkt_len);
  81         dltname = pcap_datalink_val_to_name(dlt);
  82         if (!ndo->ndo_qflag) {
  83                 ND_PRINT("DLT %s (%u) len %u",
  84                           (dltname != NULL ? dltname : "UNKNOWN"), dlt, hdrlen);
  85         } else {
  86                 ND_PRINT("%s", (dltname != NULL ? dltname : "UNKNOWN"));
  87         }
  88
  89         ND_PRINT(", length %u: ", length);
  90 }
  91
  92 /*
  93  * This is the top level routine of the printer.  'p' points
  94  * to the ether header of the packet, 'h->ts' is the timestamp,
  95  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
  96  * is the number of bytes actually captured.
  97  */
  98 u_int
  99 pktap_if_print(netdissect_options *ndo,
 100                const struct pcap_pkthdr *h, const u_char *p)
 101 {
 102         uint32_t dlt, hdrlen, rectype;
 103         u_int caplen = h->caplen;
 104         u_int length = h->len;
 105         if_printer printer;
 106         const pktap_header_t *hdr;
 107         struct pcap_pkthdr nhdr;
 108
 109         ndo->ndo_protocol = "pktap_if";
 110         if (caplen < sizeof(pktap_header_t) || length < sizeof(pktap_header_t)) {
 111                 ND_PRINT("[|pktap]");
 112                 return (caplen);
 113         }
 114         hdr = (const pktap_header_t *)p;
 115         dlt = EXTRACT_LE_U_4(hdr->pkt_dlt);
 116         hdrlen = EXTRACT_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("[|pktap]");
 126                 return (caplen);
 127         }
 128         if (caplen < hdrlen || length < hdrlen) {
 129                 ND_PRINT("[|pktap]");
 130                 return (caplen);
 131         }
 132
 133         if (ndo->ndo_eflag)
 134                 pktap_header_print(ndo, p, length);
 135
 136         length -= hdrlen;
 137         caplen -= hdrlen;
 138         p += hdrlen;
 139
 140         rectype = EXTRACT_LE_U_4(hdr->pkt_rectype);
 141         switch (rectype) {
 142
 143         case PKT_REC_NONE:
 144                 ND_PRINT("no data");
 145                 break;
 146
 147         case PKT_REC_PACKET:
 148                 if ((printer = lookup_printer(dlt)) != NULL) {
 149                         nhdr = *h;
 150                         nhdr.caplen = caplen;
 151                         nhdr.len = length;
 152                         hdrlen += printer(ndo, &nhdr, p);
 153                 } else {
 154                         if (!ndo->ndo_eflag)
 155                                 pktap_header_print(ndo, (const u_char *)hdr,
 156                                                 length + hdrlen);
 157
 158                         if (!ndo->ndo_suppress_default_print)
 159                                 ND_DEFAULTPRINT(p, caplen);
 160                 }
 161                 break;
 162         }
 163
 164         return (hdrlen);
 165 }
 166 #endif /* DLT_PKTAP */