util-lua-packetlib.c

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/* 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;
}