/* Copyright (C) 2025 Open Information Security Foundation

 *

 * You can copy, redistribute or modify this Program under the terms of

 * the GNU General Public License version 2 as published by the Free

 * Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * version 2 along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

/**

 * \file

 *

 * Packet API for Lua.

 *

 * local packet = require("suricata.packet")

 */

#include "suricata-common.h"

#include "util-lua-packetlib.h"

#include "app-layer-protos.h" /* Required by util-lua-common. */

#include "util-lua-common.h"

#include "util-lua.h"

#include "util-debug.h"

#include "util-print.h"

static const char suricata_packet[] = "suricata:packet";

/* no stored pointer: the accessors act on the packet the state is

 * running on (LuaStateGetPacket), so a retained handle can never

 * dangle */

struct LuaPacket {

};

static int LuaPacketPayload(lua_State *luastate)

{

    SCLuaCheckUserData(luastate, 1, suricata_packet, SCLUA_TUD_PACKET);

    Packet *p = LuaStateGetPacket(luastate);

    if (p == NULL) {

        LUA_ERROR("failed to get packet");

    }

    LuaPushStringBuffer(luastate, (const uint8_t *)p->payload, (size_t)p->payload_len);

    return 1;

}

static int LuaPacketPacket(lua_State *luastate)

{

    SCLuaCheckUserData(luastate, 1, suricata_packet, SCLUA_TUD_PACKET);

    Packet *p = LuaStateGetPacket(luastate);

    if (p == NULL) {

        LUA_ERROR("failed to get packet");

    }

    LuaPushStringBuffer(luastate, (const uint8_t *)GET_PKT_DATA(p), (size_t)GET_PKT_LEN(p));

    return 1;

}

static int LuaPacketPcapCnt(lua_State *luastate)

{

    SCLuaCheckUserData(luastate, 1, suricata_packet, SCLUA_TUD_PACKET);

    Packet *p = LuaStateGetPacket(luastate);

    if (p == NULL) {

        LUA_ERROR("failed to get packet");

    }

    lua_pushinteger(luastate, PcapPacketCntGet(p));

    return 1;

}

/** \internal

 *  \brief legacy format as used by fast.log, etc.

 */

static int LuaPacketTimestringLegacy(lua_State *luastate)

{

    SCLuaCheckUserData(luastate, 1, suricata_packet, SCLUA_TUD_PACKET);

    Packet *p = LuaStateGetPacket(luastate);

    if (p == NULL) {

        LUA_ERROR("failed to get packet");

    }

    char timebuf[64];

    CreateTimeString(p->ts, timebuf, sizeof(timebuf));

    lua_pushstring(luastate, timebuf);

    return 1;

}

static int LuaPacketTimestringIso8601(lua_State *luastate)

{

    SCLuaCheckUserData(luastate, 1, suricata_packet, SCLUA_TUD_PACKET);

    Packet *p = LuaStateGetPacket(luastate);

    if (p == NULL) {

        LUA_ERROR("failed to get packet");

    }

    char timebuf[64];

    CreateIsoTimeString(p->ts, timebuf, sizeof(timebuf));

    lua_pushstring(luastate, timebuf);

    return 1;

}

static int LuaPacketTimestamp(lua_State *luastate)

{

    SCLuaCheckUserData(luastate, 1, suricata_packet, SCLUA_TUD_PACKET);

    Packet *p = LuaStateGetPacket(luastate);

    if (p == NULL) {

        LUA_ERROR("failed to get packet");

    }

    lua_pushnumber(luastate, (double)SCTIME_SECS(p->ts));

    lua_pushnumber(luastate, (double)SCTIME_USECS(p->ts));

    return 2;

}

/** \internal

 *  \brief fill lua stack with header info

 *  \param luastate the lua state

 *  \retval cnt number of data items placed on the stack

 *

 *  Places: ipver (number), src ip (string), dst ip (string), protocol (number),

 *          sp or icmp type (number), dp or icmp code (number).

 */

static int LuaPacketTuple(lua_State *luastate)

{

    SCLuaCheckUserData(luastate, 1, suricata_packet, SCLUA_TUD_PACKET);

    Packet *p = LuaStateGetPacket(luastate);

    if (p == NULL) {

        LUA_ERROR("failed to get packet");

    }

    int ipver = 0;

    if (PacketIsIPv4(p)) {

        ipver = 4;

    } else if (PacketIsIPv6(p)) {

        ipver = 6;

    }

    lua_pushinteger(luastate, ipver);

    if (ipver == 0)

        return 1;

    char srcip[46] = "", dstip[46] = "";

    if (PacketIsIPv4(p)) {

        PrintInet(AF_INET, (const void *)GET_IPV4_SRC_ADDR_PTR(p), srcip, sizeof(srcip));

        PrintInet(AF_INET, (const void *)GET_IPV4_DST_ADDR_PTR(p), dstip, sizeof(dstip));

    } else if (PacketIsIPv6(p)) {

        PrintInet(AF_INET6, (const void *)GET_IPV6_SRC_ADDR(p), srcip, sizeof(srcip));

        PrintInet(AF_INET6, (const void *)GET_IPV6_DST_ADDR(p), dstip, sizeof(dstip));

    }

    lua_pushstring(luastate, srcip);

    lua_pushstring(luastate, dstip);

    /* proto and ports (or type/code) */

    lua_pushinteger(luastate, p->proto);

    if (p->proto == IPPROTO_TCP || p->proto == IPPROTO_UDP) {

        lua_pushinteger(luastate, p->sp);

        lua_pushinteger(luastate, p->dp);

    } else if (p->proto == IPPROTO_ICMP || p->proto == IPPROTO_ICMPV6) {

        lua_pushinteger(luastate, p->icmp_s.type);

        lua_pushinteger(luastate, p->icmp_s.code);

    } else {

        lua_pushinteger(luastate, 0);

        lua_pushinteger(luastate, 0);

    }

    return 6;

}

/** \internal

 *  \brief get tcp/udp/sctp source port

 *  \param luastate the lua state

 */

static int LuaPacketSport(lua_State *luastate)

{

    SCLuaCheckUserData(luastate, 1, suricata_packet, SCLUA_TUD_PACKET);

    Packet *p = LuaStateGetPacket(luastate);

    if (p == NULL) {

        LUA_ERROR("failed to get packet");

    }

    switch (p->proto) {

        case IPPROTO_TCP:

        case IPPROTO_UDP:

        case IPPROTO_SCTP:

            lua_pushinteger(luastate, p->sp);

            break;

        default:

            LUA_ERROR("sp only available for tcp, udp and sctp");

    }

    return 1;

}

/** \internal

 *  \brief get tcp/udp/sctp dest port

 *  \param luastate the lua state

 */

static int LuaPacketDport(lua_State *luastate)

{

    SCLuaCheckUserData(luastate, 1, suricata_packet, SCLUA_TUD_PACKET);

    Packet *p = LuaStateGetPacket(luastate);

    if (p == NULL) {

        LUA_ERROR("failed to get packet");

    }

    switch (p->proto) {

        case IPPROTO_TCP:

        case IPPROTO_UDP:

        case IPPROTO_SCTP:

            lua_pushinteger(luastate, p->dp);

            break;

        default:

            LUA_ERROR("dp only available for tcp, udp and sctp");

    }

    return 1;

}

static int LuaPacketGet(lua_State *luastate)

{

    Packet *p = LuaStateGetPacket(luastate);

    if (p == NULL) {

        LUA_ERROR("failed to get packet");

    }

    struct LuaPacket *s = SCLuaNewUserData(luastate, SCLUA_TUD_PACKET, sizeof(*s));

    if (s == NULL) {

        LUA_ERROR("failed to get userdata");

    }

    luaL_getmetatable(luastate, suricata_packet);

    lua_setmetatable(luastate, -2);

    return 1;

}

static const luaL_Reg packetlib[] = {

    // clang-format off

    { "get", LuaPacketGet },

    { NULL, NULL }

    // clang-format on

};

static const luaL_Reg packetlib_meta[] = {

    // clang-format off

    { "packet", LuaPacketPacket },

    { "payload", LuaPacketPayload },

    { "pcap_cnt", LuaPacketPcapCnt },

    { "timestring_legacy", LuaPacketTimestringLegacy },

    { "timestring_iso8601", LuaPacketTimestringIso8601 },

    { "timestamp", LuaPacketTimestamp },

    { "tuple", LuaPacketTuple },

    { "sp", LuaPacketSport },

    { "dp", LuaPacketDport },

    { NULL, NULL }

    // clang-format on

};

int LuaLoadPacketLib(lua_State *luastate)

{

    luaL_newmetatable(luastate, suricata_packet);

    lua_pushvalue(luastate, -1);

    lua_setfield(luastate, -2, "__index");

    luaL_setfuncs(luastate, packetlib_meta, 0);

    luaL_newlib(luastate, packetlib);

    return 1;

}