/*
* Copyright (c) 2013, Petar Alilovic,
* Faculty of Electrical Engineering and Computing, University of Zagreb
* All rights reserved
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
*       this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
*       notice, this list of conditions and the following disclaimer in the
*       documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*/

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: print-nflog.c,v 1.5 2024/09/02 16:15:32 christos Exp $");
#endif

/* \summary: DLT_NFLOG printer */

#include <config.h>

#include "netdissect-stdinc.h"

#include "netdissect.h"
#include "extract.h"

#ifdef DLT_NFLOG

/*
* Structure of an NFLOG header and TLV parts, as described at
* https://www.tcpdump.org/linktypes/LINKTYPE_NFLOG.html
*
* The NFLOG header is big-endian.
*
* The TLV length and type are in host byte order.  The value is either
* big-endian or is an array of bytes in some externally-specified byte
* order (text string, link-layer address, link-layer header, packet
* data, etc.).
*/
typedef struct nflog_hdr {
       nd_uint8_t      nflog_family;           /* address family */
       nd_uint8_t      nflog_version;          /* version */
       nd_uint16_t     nflog_rid;              /* resource ID */
} nflog_hdr_t;

#define NFLOG_HDR_LEN sizeof(nflog_hdr_t)

typedef struct nflog_tlv {
       nd_uint16_t     tlv_length;             /* tlv length */
       nd_uint16_t     tlv_type;               /* tlv type */
       /* value follows this */
} nflog_tlv_t;

#define NFLOG_TLV_LEN sizeof(nflog_tlv_t)

typedef struct nflog_packet_hdr {
       nd_uint16_t     hw_protocol;    /* hw protocol */
       nd_uint8_t      hook;           /* netfilter hook */
       nd_byte         pad[1];         /* padding to 32 bits */
} nflog_packet_hdr_t;

typedef struct nflog_hwaddr {
       nd_uint16_t     hw_addrlen;     /* address length */
       nd_byte         pad[2];         /* padding to 32-bit boundary */
       nd_byte         hw_addr[8];     /* address, up to 8 bytes */
} nflog_hwaddr_t;

typedef struct nflog_timestamp {
       nd_uint64_t     sec;
       nd_uint64_t     usec;
} nflog_timestamp_t;

/*
* TLV types.
*/
#define NFULA_PACKET_HDR                1       /* nflog_packet_hdr_t */
#define NFULA_MARK                      2       /* packet mark from skbuff */
#define NFULA_TIMESTAMP                 3       /* nflog_timestamp_t for skbuff's time stamp */
#define NFULA_IFINDEX_INDEV             4       /* ifindex of device on which packet received (possibly bridge group) */
#define NFULA_IFINDEX_OUTDEV            5       /* ifindex of device on which packet transmitted (possibly bridge group) */
#define NFULA_IFINDEX_PHYSINDEV         6       /* ifindex of physical device on which packet received (not bridge group) */
#define NFULA_IFINDEX_PHYSOUTDEV        7       /* ifindex of physical device on which packet transmitted (not bridge group) */
#define NFULA_HWADDR                    8       /* nflog_hwaddr_t for hardware address */
#define NFULA_PAYLOAD                   9       /* packet payload */
#define NFULA_PREFIX                    10      /* text string - null-terminated, count includes NUL */
#define NFULA_UID                       11      /* UID owning socket on which packet was sent/received */
#define NFULA_SEQ                       12      /* sequence number of packets on this NFLOG socket */
#define NFULA_SEQ_GLOBAL                13      /* sequence number of packets on all NFLOG sockets */
#define NFULA_GID                       14      /* GID owning socket on which packet was sent/received */
#define NFULA_HWTYPE                    15      /* ARPHRD_ type of skbuff's device */
#define NFULA_HWHEADER                  16      /* skbuff's MAC-layer header */
#define NFULA_HWLEN                     17      /* length of skbuff's MAC-layer header */

/*
* Define two constants specifically for the two AF code points from the
* LINKTYPE_NFLOG specification above and use these constants instead of
* AF_INET and AF_INET6.  This is the only way to dissect the "wire" encoding
* correctly because some BSD systems define AF_INET6 differently from Linux
* (see af.h) and Haiku defines both AF_INET and AF_INET6 differently from
* Linux.
*/
#define NFLOG_AF_INET   2
#define NFLOG_AF_INET6 10
static const struct tok nflog_values[] = {
       { NFLOG_AF_INET,        "IPv4" },
       { NFLOG_AF_INET6,       "IPv6" },
       { 0,                    NULL }
};

static void
nflog_hdr_print(netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length)
{
       ND_PRINT("version %u, resource ID %u",
           GET_U_1(hdr->nflog_version), GET_BE_U_2(hdr->nflog_rid));

       if (!ndo->ndo_qflag) {
               ND_PRINT(", family %s (%u)",
                        tok2str(nflog_values, "Unknown",
                                GET_U_1(hdr->nflog_family)),
                        GET_U_1(hdr->nflog_family));
               } else {
               ND_PRINT(", %s",
                        tok2str(nflog_values,
                                "Unknown NFLOG (0x%02x)",
                        GET_U_1(hdr->nflog_family)));
               }

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

void
nflog_if_print(netdissect_options *ndo,
              const struct pcap_pkthdr *h, const u_char *p)
{
       const nflog_hdr_t *hdr = (const nflog_hdr_t *)p;
       uint16_t size;
       uint16_t h_size = NFLOG_HDR_LEN;
       u_int caplen = h->caplen;
       u_int length = h->len;

       ndo->ndo_protocol = "nflog";
       if (caplen < NFLOG_HDR_LEN) {
               nd_print_trunc(ndo);
               ndo->ndo_ll_hdr_len += caplen;
               return;
       }
       ndo->ndo_ll_hdr_len += NFLOG_HDR_LEN;

       ND_TCHECK_SIZE(hdr);
       if (GET_U_1(hdr->nflog_version) != 0) {
               ND_PRINT("version %u (unknown)", GET_U_1(hdr->nflog_version));
               return;
       }

       if (ndo->ndo_eflag)
               nflog_hdr_print(ndo, hdr, length);

       p += NFLOG_HDR_LEN;
       length -= NFLOG_HDR_LEN;
       caplen -= NFLOG_HDR_LEN;

       while (length > 0) {
               const nflog_tlv_t *tlv;

               /* We have some data.  Do we have enough for the TLV header? */
               if (caplen < NFLOG_TLV_LEN)
                       goto trunc;     /* No. */

               tlv = (const nflog_tlv_t *) p;
               ND_TCHECK_SIZE(tlv);
               size = GET_HE_U_2(tlv->tlv_length);
               if (size % 4 != 0)
                       size += 4 - size % 4;

               /* Is the TLV's length less than the minimum? */
               if (size < NFLOG_TLV_LEN)
                       goto trunc;     /* Yes. Give up now. */

               /* Do we have enough data for the full TLV? */
               if (caplen < size)
                       goto trunc;     /* No. */

               if (GET_HE_U_2(tlv->tlv_type) == NFULA_PAYLOAD) {
                       /*
                        * This TLV's data is the packet payload.
                        * Skip past the TLV header, and break out
                        * of the loop so we print the packet data.
                        */
                       p += NFLOG_TLV_LEN;
                       h_size += NFLOG_TLV_LEN;
                       length -= NFLOG_TLV_LEN;
                       caplen -= NFLOG_TLV_LEN;
                       break;
               }

               p += size;
               h_size += size;
               length -= size;
               caplen -= size;
       }

       switch (GET_U_1(hdr->nflog_family)) {

       case NFLOG_AF_INET:
               ip_print(ndo, p, length);
               break;

       case NFLOG_AF_INET6:
               ip6_print(ndo, p, length);
               break;

       default:
               if (!ndo->ndo_eflag)
                       nflog_hdr_print(ndo, hdr,
                                       length + NFLOG_HDR_LEN);

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

       ndo->ndo_ll_hdr_len += h_size - NFLOG_HDR_LEN;
       return;
trunc:
       nd_print_trunc(ndo);
       ndo->ndo_ll_hdr_len += h_size - NFLOG_HDR_LEN;
}

#endif /* DLT_NFLOG */

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