/*

 * Copyright (c) 1993, 1994, 1995, 1996, 1997

 *  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.

 *

 * pcap-util.c - common code for various files

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include <pcap-types.h>

#include "pcap-int.h"

#include "extract.h"

#include "pcap-usb-linux-common.h"

#include "pcap-util.h"

#include "pflog.h"

#include "pcap/can_socketcan.h"

#include "pcap/sll.h"

#include "pcap/usb.h"

#include "pcap/nflog.h"

/*

 * Most versions of the DLT_PFLOG pseudo-header have UID and PID fields

 * that are saved in host byte order.

 *

 * When reading a DLT_PFLOG packet, we need to convert those fields from

 * the byte order of the host that wrote the file to this host's byte

 * order.

 */

static void

swap_pflog_header(const struct pcap_pkthdr *hdr, u_char *buf)

{

  u_int caplen = hdr->caplen;

  u_int length = hdr->len;

  u_int pfloghdr_length;

  struct pfloghdr *pflhdr = (struct pfloghdr *)buf;

  if (caplen < (u_int) (offsetof(struct pfloghdr, uid) + sizeof pflhdr->uid) ||

      length < (u_int) (offsetof(struct pfloghdr, uid) + sizeof pflhdr->uid)) {

    /* Not enough data to have the uid field */

    return;

  }

  pfloghdr_length = pflhdr->length;

  if (pfloghdr_length < (u_int) (offsetof(struct pfloghdr, uid) + sizeof pflhdr->uid)) {

    /* Header doesn't include uid field */

    return;

  }

  pflhdr->uid = SWAPLONG(pflhdr->uid);

  if (caplen < (u_int) (offsetof(struct pfloghdr, pid) + sizeof pflhdr->pid) ||

      length < (u_int) (offsetof(struct pfloghdr, pid) + sizeof pflhdr->pid)) {

    /* Not enough data to have the pid field */

    return;

  }

  if (pfloghdr_length < (u_int) (offsetof(struct pfloghdr, pid) + sizeof pflhdr->pid)) {

    /* Header doesn't include pid field */

    return;

  }

  pflhdr->pid = SWAPLONG(pflhdr->pid);

  if (caplen < (u_int) (offsetof(struct pfloghdr, rule_uid) + sizeof pflhdr->rule_uid) ||

      length < (u_int) (offsetof(struct pfloghdr, rule_uid) + sizeof pflhdr->rule_uid)) {

    /* Not enough data to have the rule_uid field */

    return;

  }

  if (pfloghdr_length < (u_int) (offsetof(struct pfloghdr, rule_uid) + sizeof pflhdr->rule_uid)) {

    /* Header doesn't include rule_uid field */

    return;

  }

  pflhdr->rule_uid = SWAPLONG(pflhdr->rule_uid);

  if (caplen < (u_int) (offsetof(struct pfloghdr, rule_pid) + sizeof pflhdr->rule_pid) ||

      length < (u_int) (offsetof(struct pfloghdr, rule_pid) + sizeof pflhdr->rule_pid)) {

    /* Not enough data to have the rule_pid field */

    return;

  }

  if (pfloghdr_length < (u_int) (offsetof(struct pfloghdr, rule_pid) + sizeof pflhdr->rule_pid)) {

    /* Header doesn't include rule_pid field */

    return;

  }

  pflhdr->rule_pid = SWAPLONG(pflhdr->rule_pid);

}

/*

 * DLT_LINUX_SLL packets with a protocol type of LINUX_SLL_P_CAN or

 * LINUX_SLL_P_CANFD have SocketCAN headers in front of the payload,

 * with the CAN ID being in host byte order.

 *

 * When reading a DLT_LINUX_SLL packet, we need to check for those

 * packets and convert the CAN ID from the byte order of the host that

 * wrote the file to this host's byte order.

 */

static void

swap_linux_sll_header(const struct pcap_pkthdr *hdr, u_char *buf)

{

  u_int caplen = hdr->caplen;

  u_int length = hdr->len;

  struct sll_header *shdr = (struct sll_header *)buf;

  uint16_t protocol;

  pcap_can_socketcan_hdr *chdr;

  if (caplen < (u_int) sizeof(struct sll_header) ||

      length < (u_int) sizeof(struct sll_header)) {

    /* Not enough data to have the protocol field */

    return;

  }

  protocol = EXTRACT_BE_U_2(&shdr->sll_protocol);

  if (protocol != LINUX_SLL_P_CAN && protocol != LINUX_SLL_P_CANFD)

    return;

  /*

   * SocketCAN packet; fix up the packet's header.

   */

  chdr = (pcap_can_socketcan_hdr *)(buf + sizeof(struct sll_header));

  if (caplen < (u_int) sizeof(struct sll_header) + sizeof(chdr->can_id) ||

      length < (u_int) sizeof(struct sll_header) + sizeof(chdr->can_id)) {

    /* Not enough data to have the CAN ID */

    return;

  }

  chdr->can_id = SWAPLONG(chdr->can_id);

}

/*

 * The same applies for DLT_LINUX_SLL2.

 */

static void

swap_linux_sll2_header(const struct pcap_pkthdr *hdr, u_char *buf)

{

  u_int caplen = hdr->caplen;

  u_int length = hdr->len;

  struct sll2_header *shdr = (struct sll2_header *)buf;

  uint16_t protocol;

  pcap_can_socketcan_hdr *chdr;

  if (caplen < (u_int) sizeof(struct sll2_header) ||

      length < (u_int) sizeof(struct sll2_header)) {

    /* Not enough data to have the protocol field */

    return;

  }

  protocol = EXTRACT_BE_U_2(&shdr->sll2_protocol);

  if (protocol != LINUX_SLL_P_CAN && protocol != LINUX_SLL_P_CANFD)

    return;

  /*

   * SocketCAN packet; fix up the packet's header.

   */

  chdr = (pcap_can_socketcan_hdr *)(buf + sizeof(struct sll2_header));

  if (caplen < (u_int) sizeof(struct sll2_header) + sizeof(chdr->can_id) ||

      length < (u_int) sizeof(struct sll2_header) + sizeof(chdr->can_id)) {

    /* Not enough data to have the CAN ID */

    return;

  }

  chdr->can_id = SWAPLONG(chdr->can_id);

}

/*

 * The DLT_USB_LINUX and DLT_USB_LINUX_MMAPPED headers are in host

 * byte order when capturing (it's supplied directly from a

 * memory-mapped buffer shared by the kernel).

 *

 * When reading a DLT_USB_LINUX or DLT_USB_LINUX_MMAPPED packet, we

 * need to convert it from the byte order of the host that wrote the

 * file to this host's byte order.

 */

static void

swap_linux_usb_header(const struct pcap_pkthdr *hdr, u_char *buf,

    int header_len_64_bytes)

{

  pcap_usb_header_mmapped *uhdr = (pcap_usb_header_mmapped *)buf;

  bpf_u_int32 offset = 0;

  /*

   * "offset" is the offset *past* the field we're swapping;

   * we skip the field *before* checking to make sure

   * the captured data length includes the entire field.

   */

  /*

   * The URB id is a totally opaque value; do we really need to

   * convert it to the reading host's byte order???

   */

  offset += 8;      /* skip past id */

  if (hdr->caplen < offset)

    return;

  uhdr->id = SWAPLL(uhdr->id);

  offset += 4;      /* skip past various 1-byte fields */

  offset += 2;      /* skip past bus_id */

  if (hdr->caplen < offset)

    return;

  uhdr->bus_id = SWAPSHORT(uhdr->bus_id);

  offset += 2;      /* skip past various 1-byte fields */

  offset += 8;      /* skip past ts_sec */

  if (hdr->caplen < offset)

    return;

  uhdr->ts_sec = SWAPLL(uhdr->ts_sec);

  offset += 4;      /* skip past ts_usec */

  if (hdr->caplen < offset)

    return;

  uhdr->ts_usec = SWAPLONG(uhdr->ts_usec);

  offset += 4;      /* skip past status */

  if (hdr->caplen < offset)

    return;

  uhdr->status = SWAPLONG(uhdr->status);

  offset += 4;      /* skip past urb_len */

  if (hdr->caplen < offset)

    return;

  uhdr->urb_len = SWAPLONG(uhdr->urb_len);

  offset += 4;      /* skip past data_len */

  if (hdr->caplen < offset)

    return;

  uhdr->data_len = SWAPLONG(uhdr->data_len);

  if (uhdr->transfer_type == URB_ISOCHRONOUS) {

    offset += 4;      /* skip past s.iso.error_count */

    if (hdr->caplen < offset)

      return;

    uhdr->s.iso.error_count = SWAPLONG(uhdr->s.iso.error_count);

    offset += 4;      /* skip past s.iso.numdesc */

    if (hdr->caplen < offset)

      return;

    uhdr->s.iso.numdesc = SWAPLONG(uhdr->s.iso.numdesc);

  } else

    offset += 8;      /* skip USB setup header */

  /*

   * With the old header, there are no isochronous descriptors

   * after the header.

   *

   * With the new header, the actual number of descriptors in

   * the header is not s.iso.numdesc, it's ndesc - only the

   * first N descriptors, for some value of N, are put into

   * the header, and ndesc is set to the actual number copied.

   * In addition, if s.iso.numdesc is negative, no descriptors

   * are captured, and ndesc is set to 0.

   */

  if (header_len_64_bytes) {

    /*

     * This is either the "version 1" header, with

     * 16 bytes of additional fields at the end, or

     * a "version 0" header from a memory-mapped

     * capture, with 16 bytes of zeroed-out padding

     * at the end.  Byte swap them as if this were

     * a "version 1" header.

     */

    offset += 4;      /* skip past interval */

    if (hdr->caplen < offset)

      return;

    uhdr->interval = SWAPLONG(uhdr->interval);

    offset += 4;      /* skip past start_frame */

    if (hdr->caplen < offset)

      return;

    uhdr->start_frame = SWAPLONG(uhdr->start_frame);

    offset += 4;      /* skip past xfer_flags */

    if (hdr->caplen < offset)

      return;

    uhdr->xfer_flags = SWAPLONG(uhdr->xfer_flags);

    offset += 4;      /* skip past ndesc */

    if (hdr->caplen < offset)

      return;

    uhdr->ndesc = SWAPLONG(uhdr->ndesc);

    if (uhdr->transfer_type == URB_ISOCHRONOUS) {

      /* swap the values in struct linux_usb_isodesc */

      usb_isodesc *pisodesc;

      uint32_t i;

      pisodesc = (usb_isodesc *)(void *)(buf+offset);

      for (i = 0; i < uhdr->ndesc; i++) {

        offset += 4;    /* skip past status */

        if (hdr->caplen < offset)

          return;

        pisodesc->status = SWAPLONG(pisodesc->status);

        offset += 4;    /* skip past offset */

        if (hdr->caplen < offset)

          return;

        pisodesc->offset = SWAPLONG(pisodesc->offset);

        offset += 4;    /* skip past len */

        if (hdr->caplen < offset)

          return;

        pisodesc->len = SWAPLONG(pisodesc->len);

        offset += 4;    /* skip past padding */

        pisodesc++;

      }

    }

  }

}

/*

 * The DLT_NFLOG "packets" have a mixture of big-endian and host-byte-order

 * data.  They begin with a fixed-length header with big-endian fields,

 * followed by a set of TLVs, where the type and length are in host

 * byte order but the values are either big-endian or are a raw byte

 * sequence that's the same regardless of the host's byte order.

 *

 * When reading a DLT_NFLOG packet, we need to convert the type and

 * length values from the byte order of the host that wrote the file

 * to the byte order of this host.

 */

static void

swap_nflog_header(const struct pcap_pkthdr *hdr, u_char *buf)

{

  u_char *p = buf;

  nflog_hdr_t *nfhdr = (nflog_hdr_t *)buf;

  nflog_tlv_t *tlv;

  u_int caplen = hdr->caplen;

  u_int length = hdr->len;

  uint16_t size;

  if (caplen < (u_int) sizeof(nflog_hdr_t) ||

      length < (u_int) sizeof(nflog_hdr_t)) {

    /* Not enough data to have any TLVs. */

    return;

  }

  if (nfhdr->nflog_version != 0) {

    /* Unknown NFLOG version */

    return;

  }

  length -= sizeof(nflog_hdr_t);

  caplen -= sizeof(nflog_hdr_t);

  p += sizeof(nflog_hdr_t);

  while (caplen >= sizeof(nflog_tlv_t)) {

    tlv = (nflog_tlv_t *) p;

    /* Swap the type and length. */

    tlv->tlv_type = SWAPSHORT(tlv->tlv_type);

    tlv->tlv_length = SWAPSHORT(tlv->tlv_length);

    /* Get the length of the TLV. */

    size = tlv->tlv_length;

    if (size % 4 != 0)

      size += 4 - size % 4;

    /* Is the TLV's length less than the minimum? */

    if (size < sizeof(nflog_tlv_t)) {

      /* Yes. Give up now. */

      return;

    }

    /* Do we have enough data for the full TLV? */

    if (caplen < size || length < size) {

      /* No. */

      return;

    }

    /* Skip over the TLV. */

    length -= size;

    caplen -= size;

    p += size;

  }

}

static void

swap_pseudo_headers(int linktype, struct pcap_pkthdr *hdr, u_char *data)

{

  /*

   * Convert pseudo-headers from the byte order of

   * the host on which the file was saved to our

   * byte order, as necessary.

   */

  switch (linktype) {

  case DLT_PFLOG:

    swap_pflog_header(hdr, data);

    break;

  case DLT_LINUX_SLL:

    swap_linux_sll_header(hdr, data);

    break;

  case DLT_LINUX_SLL2:

    swap_linux_sll2_header(hdr, data);

    break;

  case DLT_USB_LINUX:

    swap_linux_usb_header(hdr, data, 0);

    break;

  case DLT_USB_LINUX_MMAPPED:

    swap_linux_usb_header(hdr, data, 1);

    break;

  case DLT_NFLOG:

    swap_nflog_header(hdr, data);

    break;

  }

}

void

pcap_post_process(int linktype, int swapped, struct pcap_pkthdr *hdr,

    u_char *data)

{

  if (swapped)

    swap_pseudo_headers(linktype, hdr, data);

  fixup_pcap_pkthdr(linktype, hdr, data);

}

void

fixup_pcap_pkthdr(int linktype, struct pcap_pkthdr *hdr, const u_char *data)

{

  const pcap_usb_header_mmapped *usb_hdr;

  usb_hdr = (const pcap_usb_header_mmapped *) data;

  if (linktype == DLT_USB_LINUX_MMAPPED &&

      hdr->caplen >= sizeof (pcap_usb_header_mmapped)) {

    /*

     * In older versions of libpcap, in memory-mapped captures,

     * the "on-the-bus length" for completion events for

     * incoming isochronous transfers was miscalculated; it

     * needed to be calculated based on the* offsets and lengths

     * in the descriptors, not on the raw URB length, but it

     * wasn't.

     *

     * If this packet contains transferred data (yes, data_flag

     * is 0 if we *do* have data), and the total on-the-network

     * length is equal to the value calculated from the raw URB

     * length, then it might be one of those transfers.

     *

     * We only do this if we have the full USB pseudo-header.

     */

    if (!usb_hdr->data_flag &&

        hdr->len == sizeof(pcap_usb_header_mmapped) +

          (usb_hdr->ndesc * sizeof (usb_isodesc)) + usb_hdr->urb_len) {

      /*

       * It might need fixing; fix it if it's a completion

       * event for an incoming isochronous transfer.

       */

      fix_linux_usb_mmapped_length(hdr, data);

    }

  }

}