wtp_pdu.c

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/* ==================================================================== 
 * The Kannel Software License, Version 1.0 
 * 
 * Copyright (c) 2001-2018 Kannel Group  
 * Copyright (c) 1998-2001 WapIT Ltd.   
 * All rights reserved. 
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met: 
 * 
 * 1. Redistributions of source code must retain the above copyright 
 *    notice, this list of conditions and the following disclaimer. 
 * 
 * 2. 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. 
 * 
 * 3. The end-user documentation included with the redistribution, 
 *    if any, must include the following acknowledgment: 
 *       "This product includes software developed by the 
 *        Kannel Group (http://www.kannel.org/)." 
 *    Alternately, this acknowledgment may appear in the software itself, 
 *    if and wherever such third-party acknowledgments normally appear. 
 * 
 * 4. The names "Kannel" and "Kannel Group" must not be used to 
 *    endorse or promote products derived from this software without 
 *    prior written permission. For written permission, please  
 *    contact org@kannel.org. 
 * 
 * 5. Products derived from this software may not be called "Kannel", 
 *    nor may "Kannel" appear in their name, without prior written 
 *    permission of the Kannel Group. 
 * 
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 KANNEL GROUP OR ITS 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. 
 * ==================================================================== 
 * 
 * This software consists of voluntary contributions made by many 
 * individuals on behalf of the Kannel Group.  For more information on  
 * the Kannel Group, please see <http://www.kannel.org/>. 
 * 
 * Portions of this software are based upon software originally written at  
 * WapIT Ltd., Helsinki, Finland for the Kannel project.  
 */ 

/* wtp_pdu.c - pack and unpack WTP packets
 *
 * Generates packing and unpacking code from wtp_pdu.def.
 *
 * Richard Braakman
 */

#include "gwlib/gwlib.h"
#include "wtp_pdu.h"

WTP_PDU *wtp_pdu_create(int type) {
    WTP_PDU *pdu;
    
    pdu = gw_malloc(sizeof(*pdu));
    pdu->type = type;
    pdu->options = NULL;

    switch (pdu->type) {
#define PDU(name, docstring, fields, is_valid) \
    case name: {\
    struct name *p; p = &pdu->u.name; \
    fields \
    } break;
#define UINT(field, docstring, bits) p->field = 0;
#define UINTVAR(field, docstring) p->field = 0;
#define OCTSTR(field, docstring, lengthfield) p->field = NULL;
#define REST(field, docstring) p->field = NULL;
#define TYPE(bits, value) 
#define RESERVED(bits) 
#define TPI(confield)
#include "wtp_pdu.def"
#undef TPI
#undef RESERVED
#undef TYPE
#undef REST
#undef OCTSTR
#undef UINTVAR
#undef UINT
#undef PDU
    default:
        warning(0, "Cannot create unknown WTP PDU type %d", pdu->type);
        break;
    }

    return pdu;
}

void wtp_pdu_destroy(WTP_PDU *pdu) {
    if (pdu == NULL)
        return;

    switch (pdu->type) {
#define PDU(name, docstring, fields, is_valid) \
    case name: {\
    struct name *p; p = &pdu->u.name; \
    fields \
    } break;
#define UINT(field, docstring, bits)
#define UINTVAR(field, docstring)
#define OCTSTR(field, docstring, lengthfield) octstr_destroy(p->field);
#define REST(field, docstring) octstr_destroy(p->field);
#define TYPE(bits, value)
#define RESERVED(bits)
#define TPI(confield)
#include "wtp_pdu.def"
#undef TPI
#undef RESERVED
#undef TYPE
#undef REST
#undef OCTSTR
#undef UINTVAR
#undef UINT
#undef PDU
    default:
        warning(0, "Cannot destroy unknown WTP PDU type %d", pdu->type);
        break;
    }

    if (pdu->options) {
        while (gwlist_len(pdu->options)) {
            wtp_tpi_destroy(gwlist_consume(pdu->options));
        }
        gwlist_destroy(pdu->options, NULL);
    }

    gw_free(pdu);
}

void wtp_tpi_destroy(WTP_TPI *p) {
    if (p == NULL)
        return;

    octstr_destroy(p->data);
    gw_free(p);
}

void wtp_pdu_append_tpi(WTP_PDU *pdu, int type, Octstr *data) {
    WTP_TPI *tpi;

    tpi = gw_malloc(sizeof(*tpi));
    tpi->type = type;
    tpi->data = data;
    if (pdu->options == NULL)
        pdu->options = gwlist_create();
    gwlist_append(pdu->options, tpi);
}

static long unpack_tpis(Octstr *data, long bitpos, WTP_PDU *pdu) {
    long length;
    int type;
    Octstr *tpidata;
    int another;

    do {
        another = octstr_get_bits(data, bitpos, 1);
        type = octstr_get_bits(data, bitpos + 1, 4);
        if (octstr_get_bits(data, bitpos + 5, 1)) {
            /* Long TPI */
            length = octstr_get_bits(data, bitpos + 8, 8);
            bitpos += 16;
        } else {
            /* Short TPI */
            length = octstr_get_bits(data, bitpos + 6, 2);
            bitpos += 8;
        }
        gw_assert(bitpos % 8 == 0);
        tpidata = octstr_copy(data, bitpos / 8, length);
        bitpos += 8 * length;
        wtp_pdu_append_tpi(pdu, type, tpidata);
    } while (another);

    return bitpos;
}

static long pack_tpis(Octstr *data, long bitpos, List *tpis) {
    long length;
    WTP_TPI *tpi;
    int i;
    int num_tpis;

    num_tpis = gwlist_len(tpis);
    for (i = 0; i < num_tpis; i++) {
        tpi = gwlist_get(tpis, i);
        length = octstr_len(tpi->data);
        octstr_set_bits(data, bitpos, 1, i + 1 < num_tpis);
        octstr_set_bits(data, bitpos + 1, 4, tpi->type);
        if (length >= 4) {
            /* Long TPI */
            octstr_set_bits(data, bitpos + 5, 1, 1);
            octstr_set_bits(data, bitpos + 8, 8, length);
            bitpos += 16;
        } else {
            /* Short TPI */
            octstr_set_bits(data, bitpos + 5, 1, 0);
            octstr_set_bits(data, bitpos + 6, 2, length);
            bitpos += 8;
        }
        gw_assert(bitpos % 8 == 0);
        octstr_append(data, tpi->data);
        bitpos += 8 * length;
    }

    return bitpos;
}

static void dump_tpis(List *tpis, int level) {
    int i;
    int num_tpis;
    WTP_TPI *tpi;

    if (tpis == NULL)
        return;

    num_tpis = gwlist_len(tpis);
    for (i = 0; i < num_tpis; i++) {
        tpi = gwlist_get(tpis, i);
        debug("wap.wtp", 0, "%*s TPI type %u:", level, "", tpi->type);
        octstr_dump(tpi->data, level + 1);
    }
}

/* Determine which type of PDU this is, using the TYPE macros in
 * the definition file. */
static int wtp_pdu_type(Octstr *data) {
    long bitpos;
    long lastpos = -1;
    long lastnumbits = -1;
    long lastval = -1;
    int thistype;

    /* This code looks slow, but an optimizing compiler will
     * reduce it considerably.  gcc -O2 will produce a single
     * call to octstr_get_bits, folllowed by a sequence of
     * tests on lastval. */

/* Only UINT and RESERVED fields may precede the TYPE */
#define PDU(name, docstring, fields, is_valid) \
    bitpos = 0; \
    thistype = name; \
    fields
#define UINT(field, docstring, bits) bitpos += (bits);
#define UINTVAR(field, docstring)
#define OCTSTR(field, docstring, lengthfield)
#define REST(field, docstring)
#define TYPE(bits, value) \
    if ((bits) != lastnumbits || bitpos != lastpos) { \
        lastval = octstr_get_bits(data, bitpos, (bits)); \
    } \
    if (lastval == (value)) \
        return thistype; \
    lastnumbits = (bits); \
    lastpos = bitpos;
#define RESERVED(bits) bitpos += (bits);
#define TPI(confield)
#include "wtp_pdu.def"
#undef TPI
#undef RESERVED
#undef TYPE
#undef REST
#undef OCTSTR
#undef UINTVAR
#undef UINT
#undef PDU

    return -1;
}

WTP_PDU *wtp_pdu_unpack(Octstr *data) {
    WTP_PDU *pdu = NULL;
    long bitpos = 0;

    gw_assert(data != NULL);

    pdu = gw_malloc(sizeof(*pdu));

    pdu->type = wtp_pdu_type(data);
    pdu->options = NULL;

    switch (pdu->type) {
#define PDU(name, docstring, fields, is_valid) \
    case name: { \
        struct name *p = &pdu->u.name; \
        fields \
        gw_assert(bitpos % 8 == 0); \
        if (bitpos / 8 != octstr_len(data)) { \
            warning(0, "Bad length for " #name " PDU, " \
                "expected %ld", bitpos / 8); \
        } \
        if (!(is_valid)) { \
            warning(0, #name " PDU failed %s", #is_valid); \
                        return NULL; \
        } \
    } break;
#define UINT(field, docstring, bits) \
    p->field = octstr_get_bits(data, bitpos, (bits)); \
    bitpos += (bits);
#define UINTVAR(field, docstring) \
    gw_assert(bitpos % 8 == 0); \
    p->field = octstr_get_bits(data, bitpos + 1, 7); \
    while (octstr_get_bits(data, bitpos, 1)) { \
        bitpos += 8; \
        p->field <<= 7; \
        p->field |= octstr_get_bits(data, bitpos + 1, 7); \
    } \
    bitpos += 8;
#define OCTSTR(field, docstring, lengthfield) \
    gw_assert(bitpos % 8 == 0); \
    p->field = octstr_copy(data, bitpos / 8, p->lengthfield); \
    bitpos += 8 * p->lengthfield;
#define REST(field, docstring) \
    gw_assert(bitpos % 8 == 0); \
    if (bitpos / 8 <= octstr_len(data)) { \
        p->field = octstr_copy(data, bitpos / 8, \
                octstr_len(data) - bitpos / 8); \
        bitpos = octstr_len(data) * 8; \
    } else { \
        p->field = octstr_create(""); \
    }
#define TYPE(bits, value) bitpos += (bits);
#define RESERVED(bits) bitpos += (bits);
#define TPI(confield) \
    if (p->confield) { \
        pdu->options = gwlist_create(); \
        bitpos = unpack_tpis(data, bitpos, pdu); \
    }
#include "wtp_pdu.def"
#undef TPI
#undef RESERVED
#undef TYPE
#undef REST
#undef OCTSTR
#undef UINTVAR
#undef UINT
#undef PDU
    default:
        warning(0, "WTP PDU with unknown type %d", pdu->type);
        gw_free(pdu);
        return NULL;
    }

    return pdu;
}

static void fixup_length_fields(WTP_PDU *pdu) {
    switch (pdu->type) {
#define PDU(name, docstring, fields, is_valid) \
    case name: { \
        struct name *p = &pdu->u.name; \
        fields \
    } break;
#define UINT(field, docstring, bits)
#define UINTVAR(field, docstring)
#define OCTSTR(field, docstring, lengthfield) \
    p->lengthfield = octstr_len(p->field);
#define REST(field, docstring)
#define TYPE(bits, value)
#define RESERVED(bits)
#define TPI(confield) \
    p->confield = pdu->options != NULL && gwlist_len(pdu->options) > 0;
#include "wtp_pdu.def"
#undef TPI
#undef RESERVED
#undef TYPE
#undef REST
#undef OCTSTR
#undef UINTVAR
#undef UINT
#undef PDU
    }
}

Octstr *wtp_pdu_pack(WTP_PDU *pdu) {
    Octstr *data;
    long bitpos;

    /* We rely on octstr_set_bits to lengthen our octstr as needed. */
    data = octstr_create("");

    fixup_length_fields(pdu);

    bitpos = 0;
    switch (pdu->type) {
#define PDU(name, docstring, fields, is_valid) \
    case name: { \
        struct name *p = &pdu->u.name; \
        fields \
        gw_assert(bitpos % 8 == 0); \
    } break;
#define UINT(field, docstring, bits) \
    octstr_set_bits(data, bitpos, (bits), p->field); \
    bitpos += (bits);
#define UINTVAR(field, docstring) \
    gw_assert(bitpos % 8 == 0); \
    octstr_append_uintvar(data, p->field); \
    bitpos = 8 * octstr_len(data);
#define OCTSTR(field, docstring, lengthfield) \
    gw_assert(bitpos % 8 == 0); \
    if (p->field != NULL) \
        octstr_append(data, p->field); \
    bitpos += 8 * octstr_len(p->field);
#define REST(field, docstring) \
    gw_assert(bitpos % 8 == 0); \
    if (p->field != NULL) \
        octstr_append(data, p->field); \
    bitpos += 8 * octstr_len(p->field);
#define TYPE(bits, value) \
    octstr_set_bits(data, bitpos, (bits), (value)); \
    bitpos += (bits);
#define RESERVED(bits) bitpos += (bits);
#define TPI(confield) \
    if (p->confield) { \
        bitpos = pack_tpis(data, bitpos, pdu->options); \
    }
#include "wtp_pdu.def"
#undef TPI
#undef RESERVED
#undef TYPE
#undef REST
#undef OCTSTR
#undef UINTVAR
#undef UINT
#undef PDU
    default:
        panic(0, "Packing unknown WTP PDU type %ld", (long) pdu->type);
    }

    return data;
}

void wtp_pdu_dump(WTP_PDU *pdu, int level) {
     char *dbg = "wap.wtp";

    switch (pdu->type) {
#define PDU(name, docstring, fields, is_valid) \
    case name: { \
        struct name *p = &pdu->u.name; \
        debug(dbg, 0, "%*sWTP %s PDU at %p:", \
            level, "", #name, (void *)pdu); \
        fields \
    } break;
#define UINT(field, docstring, bits) \
    debug(dbg, 0, "%*s %s: %lu", level, "", docstring, p->field);
#define UINTVAR(field, docstring) \
    debug(dbg, 0, "%*s %s: %lu", level, "", docstring, p->field);
#define OCTSTR(field, docstring, lengthfield) \
    debug(dbg, 0, "%*s %s:", level, "", docstring); \
    octstr_dump(p->field, level + 1);
#define REST(field, docstring) \
    debug(dbg, 0, "%*s %s:", level, "", docstring); \
    octstr_dump(p->field, level + 1);
#define TYPE(bits, value)
#define RESERVED(bits)
#define TPI(confield) dump_tpis(pdu->options, level);
#include "wtp_pdu.def"
#undef TPI
#undef RESERVED
#undef TYPE
#undef REST
#undef OCTSTR
#undef UINTVAR
#undef UINT
#undef PDU
    default:
        debug(dbg, 0, "%*sWTP PDU at %p:", level, "", (void *)pdu);
        debug(dbg, 0, "%*s unknown type %u", level, "", pdu->type);
        break;
    }
}