path: root/plugins/lua/elua_tvb.c

/*
 * lua_tvb.c
 *
 * Ethereal's interface to the Lua Programming Language
 *
 * (c) 2006, Luis E. Garcia Ontanon <luis.ontanon@gmail.com>
 *
 * $Id$
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * 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
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include "elua.h"

ELUA_CLASS_DEFINE(ByteArray,FAIL_ON_NULL("null bytearray"))

ELUA_CONSTRUCTOR ByteArray_new(lua_State* L) { /* creates a ByteArray Object */
#define ELUA_OPTARG_ByteArray_new_HEXBYTES 1 /* A string consisting of hexadecimal bytes like "00 B1 A2" or "1a2b3c4d" */
    GByteArray* ba = g_byte_array_new();
    const gchar* s;
    int nibble[2];
    int i = 0;
    gchar c;

    if (lua_gettop(L) == 1) {
        s = luaL_checkstring(L,ELUA_OPTARG_ByteArray_new_HEXBYTES);
        
        if (!s) {
            ELUA_OPTARG_ERROR(ByteArray_new,HEXBYTES,"must be a string");
            return 0;
        }
        
        /* XXX: slow! */
        for (; (c = *s); s++) {
            switch(c) {
                case '0': case '1': case '2': case '3': case '4': case '5' : case '6' : case '7': case '8' : case '9' :
                    nibble[(i++)%2] = c - '0';
                    break;
                case 'a': case 'b': case 'c': case 'd': case 'e': case 'f' :
                    nibble[(i++)%2] = c - 'a' + 0xa;
                    break;
                case 'A': case 'B': case 'C': case 'D': case 'E': case 'F' :
                    nibble[(i++)%2] = c - 'A' + 0xa;
                    break;
                default:
                    break;
            }

            if ( i == 2 ) {
                guint8 b = (guint8)(nibble[0] * 16 + nibble[1]);
                g_byte_array_append(ba,&b,1);
                i = 0;
            }
        }
    } 
    
    pushByteArray(L,ba);

    ELUA_RETURN(1); /* The new ByteArray object. */
}

static int ByteArray_gc(lua_State* L) {
    ByteArray ba = checkByteArray(L,1);

    if (!ba) return 0;
    
    g_byte_array_free(ba,TRUE);
    return 0;
}

ELUA_METAMETHOD ByteArray__concat(lua_State* L) {
#define ELUA_ARG_ByteArray__cat_FIRST 1
#define ELUA_ARG_ByteArray__cat_SECOND 1
	
    ByteArray ba = checkByteArray(L,1);
    ByteArray ba2 = checkByteArray(L,2);

	if (! (ba  && ba2) )
		ELUA_ERROR(ByteArray__cat,"both arguments must be ByteArrays");
	
    g_byte_array_append(ba,ba2->data,ba2->len);

    pushByteArray(L,ba);
    ELUA_RETURN(1); /* The new composite ByteArray. */
}

ELUA_METHOD ByteArray_prepend(lua_State* L) {
#define ELUA_ARG_ByteArray_prepend_BYTES 1
    ByteArray ba = checkByteArray(L,1);
    ByteArray ba2 = checkByteArray(L,2);
    
	if (! (ba  && ba2) )
		ELUA_ERROR(ByteArray_prepend,"both arguments must be ByteArrays");

    g_byte_array_prepend(ba,ba2->data,ba2->len);
    
    pushByteArray(L,ba);
    return 1;
}

ELUA_METHOD ByteArray_append(lua_State* L) {
    ByteArray ba = checkByteArray(L,1);
    ByteArray ba2 = checkByteArray(L,2);
    
	if (! (ba  && ba2) )
		ELUA_ERROR(ByteArray_prepend,"both arguments must be ByteArrays");
	
    g_byte_array_prepend(ba,ba2->data,ba2->len);
    
    pushByteArray(L,ba);
    return 1;
}

ELUA_METHOD ByteArray_set_size(lua_State* L) {
    ByteArray ba = checkByteArray(L,1);
    int siz = luaL_checkint(L,2);

    if (!ba) return 0;

    g_byte_array_set_size(ba,siz);
    return 0;
}

ELUA_METHOD ByteArray_set_index(lua_State* L) {
    ByteArray ba = checkByteArray(L,1);
    int idx = luaL_checkint(L,2);
    int v = luaL_checkint(L,3);
    
    if (!ba) return 0;

    if (idx == 0 && ! g_str_equal(luaL_optstring(L,2,""),"0") ) {
        luaL_argerror(L,2,"bad index");
        return 0;
    }
    
    if (idx < 0 || (guint)idx >= ba->len) {
            luaL_argerror(L,2,"index out of range");
            return 0;
    }

    if (v < 0 || v > 255) {
        luaL_argerror(L,3,"Byte out of range");
        return 0;
    }
    
    ba->data[idx] = (guint8)v;
    
    return 0;
}


ELUA_METHOD ByteArray_get_index(lua_State* L) {
    ByteArray ba = checkByteArray(L,1);
    int idx = luaL_checkint(L,2);
    
    if (!ba) return 0;
    
    if (idx == 0 && ! g_str_equal(luaL_optstring(L,2,""),"0") ) {
        luaL_argerror(L,2,"bad index");
        return 0;
    }
    
    if (idx < 0 || (guint)idx >= ba->len) {
        luaL_argerror(L,2,"index out of range");
        return 0;
    }
    lua_pushnumber(L,ba->data[idx]);
    
    return 1;
}

ELUA_METHOD ByteArray_len(lua_State* L) {
    ByteArray ba = checkByteArray(L,1);
    
    if (!ba) return 0;
    
    lua_pushnumber(L,(lua_Number)ba->len);

    return 1;
}

ELUA_METHOD ByteArray_subset(lua_State* L) {
    ByteArray ba = checkByteArray(L,1);
    int offset = luaL_checkint(L,2);
    int len = luaL_checkint(L,3);
    ByteArray sub;

    if (!ba) return 0;
    
    if ((offset + len) > (int)ba->len || offset < 0 || len < 1) {
        luaL_error(L,"Out Of Bounds");
        return 0;
    }

    sub = g_byte_array_new();
    g_byte_array_append(sub,ba->data + offset,len);
    
    pushByteArray(L,sub);
    
    return 1;
}

static int ByteArray_tostring(lua_State* L) {
    static const gchar* byte_to_str[] = {
        "00","01","02","03","04","05","06","07","08","09","0A","0B","0C","0D","0E","0F",
        "10","11","12","13","14","15","16","17","18","19","1A","1B","1C","1D","1E","1F",
        "20","21","22","23","24","25","26","27","28","29","2A","2B","2C","2D","2E","2F",
        "30","31","32","33","34","35","36","37","38","39","3A","3B","3C","3D","3E","3F",
        "40","41","42","43","44","45","46","47","48","49","4A","4B","4C","4D","4E","4F",
        "50","51","52","53","54","55","56","57","58","59","5A","5B","5C","5D","5E","5F",
        "60","61","62","63","64","65","66","67","68","69","6A","6B","6C","6D","6E","6F",
        "70","71","72","73","74","75","76","77","78","79","7A","7B","7C","7D","7E","7F",
        "80","81","82","83","84","85","86","87","88","89","8A","8B","8C","8D","8E","8F",
        "90","91","92","93","94","95","96","97","98","99","9A","9B","9C","9D","9E","9F",
        "A0","A1","A2","A3","A4","A5","A6","A7","A8","A9","AA","AB","AC","AD","AE","AF",
        "B0","B1","B2","B3","B4","B5","B6","B7","B8","B9","BA","BB","BC","BD","BE","BF",
        "C0","C1","C2","C3","C4","C5","C6","C7","C8","C9","CA","CB","CC","CD","CE","CF",
        "D0","D1","D2","D3","D4","D5","D6","D7","D8","D9","DA","DB","DC","DD","DE","DF",
        "E0","E1","E2","E3","E4","E5","E6","E7","E8","E9","EA","EB","EC","ED","EE","EF",
        "F0","F1","F2","F3","F4","F5","F6","F7","F8","F9","FA","FB","FC","FD","FE","FF"
    };
    ByteArray ba = checkByteArray(L,1);
    int i;
    GString* s;
    
    if (!ba) return 0;
    
    s = g_string_new("");
    
    for (i = 0; i < (int)ba->len; i++) {
        g_string_append(s,byte_to_str[(ba->data)[i]]);
    }
    
    lua_pushstring(L,s->str);
    g_string_free(s,TRUE);
    
    return 1;
}

static int Tvb_new_real (lua_State *L);

static const luaL_reg ByteArray_methods[] = {
    {"new", ByteArray_new},
    {"len", ByteArray_len},
    {"prepend", ByteArray_prepend},
    {"append", ByteArray_append},
    {"subset", ByteArray_subset},
    {"set_size", ByteArray_set_size},
    {"tvb", Tvb_new_real},
    {"get_index", ByteArray_get_index},
    {"set_index", ByteArray_set_index},
    {0,0}
};

static const luaL_reg ByteArray_meta[] = {
    {"__tostring", ByteArray_tostring},
    {"__gc",       ByteArray_gc},
    {"__concat", ByteArray__concat},
    {"__call",ByteArray_subset},
    {0, 0}
};

int ByteArray_register(lua_State* L) {
	ELUA_REGISTER_CLASS(ByteArray);
    return 1;
}


/*
 * Tvb & TvbRange
 *
 * a Tvb represents a tvbuff_t in Lua. 
 * a TvbRange represents a range in a tvb (tvb,offset,lenght) it's main purpose is to do bounds checking, 
 *            it helps too simplifing argument passing to Tree. In ethereal terms this is worthless nothing
 *            not already done by the TVB itself. In lua's terms is necessary to avoid abusing TRY{}CATCH(){}
 *            via preemptive bounds checking. 
 *
 * These lua objects have to be "NULLified after use", that is, we cannot leave pointers in the
 * lua machine to a tvb or a tvbr that might exist anymore. 
 *
 * To do so we are going to keep a pointer to every "box" in which lua has placed a pointer to our object 
 * and then NULLify the object lua points to.
 *
 * Other than that we are going to check every instance of a potentialy NULLified object before using it
 * and report an error to the lua machine if it happens to be NULLified.
 */

ELUA_CLASS_DEFINE(Tvb,FAIL_ON_NULL("expired tvb"))

static GPtrArray* outstanding_stuff = NULL;

#define PUSH_TVB(L,t) g_ptr_array_add(outstanding_stuff,pushTvb(L,t))
#define PUSH_TVBRANGE(L,t) g_ptr_array_add(outstanding_stuff,pushTvbRange(L,t))

void clear_outstanding_tvbs(void) {
    while (outstanding_stuff->len) {
        void** p = (void**)g_ptr_array_remove_index_fast(outstanding_stuff,0);
        *p = NULL;
    }
}

void* push_Tvb(lua_State* L, Tvb tvb) {
    void** p = (void**)pushTvb(L,tvb);
    g_ptr_array_add(outstanding_stuff,p);
	return p;
}



/*
 * Tvb_new_real(bytearray,name)
 *  Creates a new Tvb from a bytearray (adds it to the frame too)
 */
static int Tvb_new_real (lua_State *L) {
    ByteArray ba = checkByteArray(L,1);
    const gchar* name = luaL_optstring(L,2,"Unnamed") ;
    guint8* data;
    Tvb tvb;
    
    if (!ba) return 0;
    
    if (!lua_tvb) {
        luaL_error(L,"Tvbs can only be created and used in dissectors");
        return 0;
    }
    
    data = g_memdup(ba->data, ba->len);
    
    tvb = tvb_new_real_data(data, ba->len,ba->len);
    tvb_set_free_cb(tvb, g_free);
    
    add_new_data_source(lua_pinfo, tvb, name);
    PUSH_TVB(L,tvb);
    return 1;
}

/*
 * creates a subtvb from a tvbrange
 *
 */
static int Tvb_new_subset (lua_State *L) {
    TvbRange tvbr = checkTvbRange(L,1);
    
    if (! tvbr) return 0;
        
    if (tvb_offset_exists(tvbr->tvb,  tvbr->offset + tvbr->len -1 )) {
        PUSH_TVB(L, tvb_new_subset(tvbr->tvb,tvbr->offset,tvbr->len, tvbr->len) );
        return 1;
    } else {
        luaL_error(L,"Out Of Bounds");
        return 0;
    }
}

/*
 * convert the bytes to string, mainly for debugging purposes (mind the ...)
 */
static int Tvb_tostring(lua_State* L) {
    Tvb tvb = checkTvb(L,1);
    int len;
    gchar* str;
    
    if (!tvb) return 0;

    len = tvb_length(tvb);
    str = ep_strdup_printf("TVB(%i) : %s",len,tvb_bytes_to_str(tvb,0,len));
    lua_pushstring(L,str);
    return 1;
}


/*
 *  returns the length of a TVB
 */
static int Tvb_len(lua_State* L) {
    Tvb tvb = checkTvb(L,1);
    
    if (!tvb) return 0;
    
    lua_pushnumber(L,tvb_length(tvb));
    return 1;
}

/*
 *  returns the raw offset of a sub TVB
 */
static int Tvb_offset(lua_State* L) {
    Tvb tvb = checkTvb(L,1);
    
    if (!tvb) return 0;
        
    lua_pushnumber(L,TVB_RAW_OFFSET(tvb));
    return 1;
}


static const luaL_reg Tvb_methods[] = {
    {"len", Tvb_len},
    {"offset", Tvb_offset},
    {0,0}
};

static int Tvb_range(lua_State* L);

static const luaL_reg Tvb_meta[] = {
    {"__call", Tvb_range},
    {"__tostring", Tvb_tostring},
    {0, 0}
};

int Tvb_register(lua_State* L) {
	ELUA_REGISTER_CLASS(Tvb);
    return 1;
}

/*
 *  TVB RAnge helper class
 *
 */

TvbRange new_TvbRange(lua_State* L, tvbuff_t* tvb, int offset, int len) {
    TvbRange tvbr;
    
    if (len == -1) {
        len = tvb_length_remaining(tvb,offset);
        if (len < 0) {
            luaL_error(L,"out of bounds");
            return 0;
        }        
    } else if ( (guint)(len + offset) > tvb_length(tvb)) {
        luaL_error(L,"Range is out of bounds");
        return NULL;
    }
    
    tvbr = ep_alloc(sizeof(struct _eth_tvbrange));
    tvbr->tvb = tvb;
    tvbr->offset = offset;
    tvbr->len = len;
    
    return tvbr;
}

/*
 *  creates a tvbr given the triplet (tvb,offset,len)
 */
static int Tvb_range(lua_State* L) {
    Tvb tvb = checkTvb(L,1);
    int offset = luaL_optint(L,2,0);
    int len = luaL_optint(L,3,-1);
    TvbRange tvbr;

    if (!tvb) return 0;

    if ((tvbr = new_TvbRange(L,tvb,offset,len))) {
        PUSH_TVBRANGE(L,tvbr);
        return 1;
    }
    
    return 0;

}

ELUA_CLASS_DEFINE(TvbRange,FAIL_ON_NULL("expired tvbrange"))

/*
 *  read access to tvbr's data
 */
static int TvbRange_get_index(lua_State* L) {
    TvbRange tvbr = checkTvbRange(L,1);
    const gchar* index = luaL_checkstring(L,2);
    
    if (!(tvbr && index)) return 0;
    
    if (g_str_equal(index,"offset")) {
        lua_pushnumber(L,(lua_Number)tvbr->offset);
        return 1;
    } else if (g_str_equal(index,"len")) {
        lua_pushnumber(L,(lua_Number)tvbr->len);
        return 1;
    } else if (g_str_equal(index,"tvb")) {
        PUSH_TVB(L,tvbr->tvb);
        return 1;
    } else {
        luaL_error(L,"TvbRange has no `%s' attribute",index);
    }
    
    return 0;
}

/*
 *  write access to tvbr's data
 */
static int TvbRange_set_index(lua_State* L) {
    TvbRange tvbr = checkTvbRange(L,1);
    const gchar* index = luaL_checkstring(L,2);

    if (!tvbr) return 0;
    
    if (g_str_equal(index,"offset")) {
        int offset = (int)lua_tonumber(L,3);
    
        if ( (guint)(tvbr->len + offset) > tvb_length(tvbr->tvb)) {
            luaL_error(L,"out of bounds");
            return 0;
        } else {
            tvbr->offset = offset;
            PUSH_TVBRANGE(L,tvbr);
            return 1;
        }
    } else if (g_str_equal(index,"len")) {
        int len = (int)lua_tonumber(L,3);
        
        if ( (guint)(tvbr->offset + len) > tvb_length(tvbr->tvb)) {
            luaL_error(L,"out of bounds");
            return 0;
        } else {
            tvbr->len = len;
            PUSH_TVBRANGE(L,tvbr);
            return 1;
        }
    } else {
        luaL_error(L,"cannot set `%s' attribute on TvbRange",index);
        return 0;
    }
    
    return 0;
}

/*
 *  get a Blefuscuoan unsigned integer from a tvb
 */
static int TvbRange_get_uint(lua_State* L) {
    TvbRange tvbr = checkTvbRange(L,1);
    if (!tvbr) return 0;
    
    switch (tvbr->len) {
        case 1:
            lua_pushnumber(L,tvb_get_guint8(tvbr->tvb,tvbr->offset));
            return 1;
        case 2:
            lua_pushnumber(L,tvb_get_ntohs(tvbr->tvb,tvbr->offset));
            return 1;
        case 3:
            lua_pushnumber(L,tvb_get_ntoh24(tvbr->tvb,tvbr->offset));
            return 1;
        case 4:
            lua_pushnumber(L,tvb_get_ntohl(tvbr->tvb,tvbr->offset));
            return 1;
            /*
             * XXX:
             *    lua uses double so we have 52 bits to play with
             *    we are missing 5 and 6 byte integers within lua's range
             *    and 64 bit integers are not supported (there's a lib for
             *    lua that does).
             */
        default:
            luaL_error(L,"TvbRange:get_uint() does not handle %d byte integers",tvbr->len);
            return 0;
    }
}

/*
 *  get a Lilliputian unsigned integer from a tvb
 */
static int TvbRange_get_le_uint(lua_State* L) {
    TvbRange tvbr = checkTvbRange(L,1);
    if (!tvbr) return 0;
    
    switch (tvbr->len) {
        case 1:
            /* XXX unsigned anyway */
            lua_pushnumber(L,(lua_Number)tvb_get_guint8(tvbr->tvb,tvbr->offset));
            return 1;
        case 2:
            lua_pushnumber(L,tvb_get_letohs(tvbr->tvb,tvbr->offset));
            return 1;
        case 3:
            lua_pushnumber(L,tvb_get_letoh24(tvbr->tvb,tvbr->offset));
            return 1;
        case 4:
            lua_pushnumber(L,tvb_get_letohl(tvbr->tvb,tvbr->offset));
            return 1;
        default:
            luaL_error(L,"TvbRange:get_le_uint() does not handle %d byte integers",tvbr->len);
            return 0;
    }
}

/*
 *  get a Blefuscuoan float
 */
static int TvbRange_get_float(lua_State* L) {
    TvbRange tvbr = checkTvbRange(L,1);
    if (!tvbr) return 0;
    
    switch (tvbr->len) {
        case 4:
            lua_pushnumber(L,(double)tvb_get_ntohieee_float(tvbr->tvb,tvbr->offset));
            return 1;
        case 8:
            lua_pushnumber(L,tvb_get_ntohieee_double(tvbr->tvb,tvbr->offset));
            return 1;
        default:
            luaL_error(L,"TvbRange:get_float() does not handle %d byte floating numbers",tvbr->len);
            return 0;
    }
}

/*
 * get a Lilliputian float
 */
static int TvbRange_get_le_float(lua_State* L) {
    TvbRange tvbr = checkTvbRange(L,1);
    if (!tvbr) return 0;
    
    switch (tvbr->len) {
        case 4:
            lua_pushnumber(L,tvb_get_letohieee_float(tvbr->tvb,tvbr->offset));
            return 1;
        case 8:
            lua_pushnumber(L,tvb_get_letohieee_double(tvbr->tvb,tvbr->offset));
            return 1;
        default:
            luaL_error(L,"TvbRange:get_float() does not handle %d byte floating numbers",tvbr->len);
            return 0;
    }
}

static int TvbRange_get_ipv4(lua_State* L) {
    TvbRange tvbr = checkTvbRange(L,1);
    Address addr;
    guint32* ip_addr;
    
    if ( !tvbr ) return 0;
    
    addr = g_malloc(sizeof(address));

    ip_addr = g_malloc(sizeof(guint32));
    *ip_addr = tvb_get_ntohl(tvbr->tvb,tvbr->offset);
    
    SET_ADDRESS(addr, AT_IPv4, 4, ip_addr); 
    pushAddress(L,addr);

    return 1;
}

static int TvbRange_get_ether(lua_State* L) {
    TvbRange tvbr = checkTvbRange(L,1);
    Address addr;
    guint8* buff;
    
    if ( !tvbr ) return 0;
    
    addr = g_malloc(sizeof(address));
    
    buff = tvb_memdup(tvbr->tvb,tvbr->offset,tvbr->len);
    
    SET_ADDRESS(addr, AT_ETHER, 6, buff); 
    pushAddress(L,addr);
    
    return 1;    
}


static int TvbRange_get_string(lua_State* L) {
    TvbRange tvbr = checkTvbRange(L,1);
    
    if ( !tvbr ) return 0;
    
    lua_pushstring(L, (gchar*)tvb_get_ephemeral_string(tvbr->tvb,tvbr->offset,tvbr->len) );
    
    return 1;
}

static int TvbRange_get_bytes(lua_State* L) {
    TvbRange tvbr = checkTvbRange(L,1);
    GByteArray* ba;
    
    if ( !tvbr ) return 0;
    
    ba = g_byte_array_new();
    g_byte_array_append(ba,ep_tvb_memdup(tvbr->tvb,tvbr->offset,tvbr->len),tvbr->len);
    
    pushByteArray(L,ba);
    
    return 1;
}

static int TvbRange_tostring(lua_State* L) {
    TvbRange tvbr = checkTvbRange(L,1);

    if (!tvbr) return 0;
    
    lua_pushstring(L,tvb_bytes_to_str(tvbr->tvb,tvbr->offset,tvbr->len));
    return 1;
}

static const luaL_reg TvbRange_methods[] = {
    {"uint", TvbRange_get_uint},
    {"le_uint", TvbRange_get_le_uint},
    {"float", TvbRange_get_float},
    {"le_float", TvbRange_get_le_float},
    {"ether", TvbRange_get_ether},
    {"ipv4", TvbRange_get_ipv4},
    {"string", TvbRange_get_string},
    {"bytes", TvbRange_get_bytes},
    {"tvb", Tvb_new_subset},
    {0, 0}
};

static const luaL_reg TvbRange_meta[] = {
    {"__index", TvbRange_get_index},
    {"__newindex", TvbRange_set_index},
    {"__tostring", TvbRange_tostring},
    {0, 0}
};

int TvbRange_register(lua_State* L) {
    outstanding_stuff = g_ptr_array_new();
    ELUA_REGISTER_CLASS(TvbRange);
    return 1;
}