/*
* Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
*      The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: print-pktap.c,v 1.7 2024/09/02 16:15:32 christos Exp $");
#endif

/* \summary: Apple's DLT_PKTAP printer */

#include <config.h>

#include "netdissect-stdinc.h"

#define ND_LONGJMP_FROM_TCHECK
#include "netdissect.h"
#include "extract.h"

#ifdef DLT_PKTAP

/*
* XXX - these are little-endian in the captures I've seen, but Apple
* no longer make any big-endian machines (Macs use x86, iOS machines
* use ARM and run it little-endian), so that might be by definition
* or they might be host-endian.
*
* If a big-endian PKTAP file ever shows up, and it comes from a
* big-endian machine, presumably these are host-endian, and we need
* to just fetch the fields directly in tcpdump but byte-swap them
* to host byte order in libpcap.
*/
typedef struct pktap_header {
       nd_uint32_t     pkt_len;        /* length of pktap header */
       nd_uint32_t     pkt_rectype;    /* type of record */
       nd_uint32_t     pkt_dlt;        /* DLT type of this packet */
       char            pkt_ifname[24]; /* interface name */
       nd_uint32_t     pkt_flags;
       nd_uint32_t     pkt_pfamily;    /* "protocol family" */
       nd_uint32_t     pkt_llhdrlen;   /* link-layer header length? */
       nd_uint32_t     pkt_lltrlrlen;  /* link-layer trailer length? */
       nd_uint32_t     pkt_pid;        /* process ID */
       char            pkt_cmdname[20]; /* command name */
       nd_uint32_t     pkt_svc_class;  /* "service class" */
       nd_uint16_t     pkt_iftype;     /* "interface type" */
       nd_uint16_t     pkt_ifunit;     /* unit number of interface? */
       nd_uint32_t     pkt_epid;       /* "effective process ID" */
       char            pkt_ecmdname[20]; /* "effective command name" */
} pktap_header_t;

/*
* Record types.
*/
#define PKT_REC_NONE    0       /* nothing follows the header */
#define PKT_REC_PACKET  1       /* a packet follows the header */

static void
pktap_header_print(netdissect_options *ndo, const u_char *bp, u_int length)
{
       const pktap_header_t *hdr;
       uint32_t dlt, hdrlen;
       const char *dltname;

       hdr = (const pktap_header_t *)bp;

       dlt = GET_LE_U_4(hdr->pkt_dlt);
       hdrlen = GET_LE_U_4(hdr->pkt_len);
       dltname = pcap_datalink_val_to_name(dlt);
       if (!ndo->ndo_qflag) {
               ND_PRINT("DLT %s (%u) len %u",
                         (dltname != NULL ? dltname : "UNKNOWN"), dlt, hdrlen);
       } else {
               ND_PRINT("%s", (dltname != NULL ? dltname : "UNKNOWN"));
       }

       ND_PRINT(", length %u: ", length);
}

/*
* This is the top level routine of the printer.  'p' points
* to the ether header of the packet, 'h->ts' is the timestamp,
* 'h->len' is the length of the packet off the wire, and 'h->caplen'
* is the number of bytes actually captured.
*/
void
pktap_if_print(netdissect_options *ndo,
              const struct pcap_pkthdr *h, const u_char *p)
{
       uint32_t dlt, hdrlen, rectype;
       u_int caplen = h->caplen;
       u_int length = h->len;
       if_printer printer;
       const pktap_header_t *hdr;
       struct pcap_pkthdr nhdr;

       ndo->ndo_protocol = "pktap";
       if (length < sizeof(pktap_header_t)) {
               ND_PRINT(" (packet too short, %u < %zu)",
                        length, sizeof(pktap_header_t));
               goto invalid;
       }
       hdr = (const pktap_header_t *)p;
       dlt = GET_LE_U_4(hdr->pkt_dlt);
       hdrlen = GET_LE_U_4(hdr->pkt_len);
       if (hdrlen < sizeof(pktap_header_t)) {
               /*
                * Claimed header length < structure length.
                * XXX - does this just mean some fields aren't
                * being supplied, or is it truly an error (i.e.,
                * is the length supplied so that the header can
                * be expanded in the future)?
                */
               ND_PRINT(" (pkt_len too small, %u < %zu)",
                        hdrlen, sizeof(pktap_header_t));
               goto invalid;
       }
       if (hdrlen > length) {
               ND_PRINT(" (pkt_len too big, %u > %u)",
                        hdrlen, length);
               goto invalid;
       }
       ND_TCHECK_LEN(p, hdrlen);

       if (ndo->ndo_eflag)
               pktap_header_print(ndo, p, length);

       length -= hdrlen;
       caplen -= hdrlen;
       p += hdrlen;

       rectype = GET_LE_U_4(hdr->pkt_rectype);
       switch (rectype) {

       case PKT_REC_NONE:
               ND_PRINT("no data");
               break;

       case PKT_REC_PACKET:
               printer = lookup_printer(dlt);
               if (printer != NULL) {
                       nhdr = *h;
                       nhdr.caplen = caplen;
                       nhdr.len = length;
                       printer(ndo, &nhdr, p);
                       hdrlen += ndo->ndo_ll_hdr_len;
               } else {
                       if (!ndo->ndo_eflag)
                               pktap_header_print(ndo, (const u_char *)hdr,
                                               length + hdrlen);

                       if (!ndo->ndo_suppress_default_print)
                               ND_DEFAULTPRINT(p, caplen);
               }
               break;
       }

       ndo->ndo_ll_hdr_len += hdrlen;
       return;

invalid:
       nd_print_invalid(ndo);
}
#endif /* DLT_PKTAP */