/* 
 * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
 * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
 *
 * 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 <pjnath/stun_msg.h>
#include <pjnath/errno.h>
#include <pjlib-util/crc32.h>
#include <pjlib-util/hmac_sha1.h>
#include <pj/assert.h>
#include <pj/log.h>
#include <pj/os.h>
#include <pj/pool.h>
#include <pj/rand.h>
#include <pj/string.h>

#define THIS_FILE               "stun_msg.c"
#define STUN_XOR_FINGERPRINT    0x5354554eL

static int padding_char;

static const char *stun_method_names[PJ_STUN_METHOD_MAX] = 
{
    "Unknown",                  /* 0 */
    "Binding",                  /* 1 */
    "SharedSecret",             /* 2 */
    "Allocate",                 /* 3 */
    "Refresh",                  /* 4 */
    "???",                      /* 5 */
    "Send",                     /* 6 */
    "Data",                     /* 7 */
    "CreatePermission",         /* 8 */
    "ChannelBind",              /* 9 */
    "Connect",                  /* 10 */
    "ConnectionBind",           /* 11 */
    "ConnectionAttempt",        /* 12 */
};

static struct
{
    int err_code;
    const char *err_msg;
} stun_err_msg_map[] = 
{
    { PJ_STUN_SC_TRY_ALTERNATE,             "Try Alternate"}, 
    { PJ_STUN_SC_BAD_REQUEST,               "Bad Request"},
    { PJ_STUN_SC_UNAUTHORIZED,              "Unauthorized"},
    { PJ_STUN_SC_FORBIDDEN,                 "Forbidden"},
    { PJ_STUN_SC_UNKNOWN_ATTRIBUTE,         "Unknown Attribute"},
    //{ PJ_STUN_SC_STALE_CREDENTIALS,       "Stale Credentials"},
    //{ PJ_STUN_SC_INTEGRITY_CHECK_FAILURE, "Integrity Check Failure"},
    //{ PJ_STUN_SC_MISSING_USERNAME,        "Missing Username"},
    //{ PJ_STUN_SC_USE_TLS,                 "Use TLS"},
    //{ PJ_STUN_SC_MISSING_REALM,           "Missing Realm"},
    //{ PJ_STUN_SC_MISSING_NONCE,           "Missing Nonce"},
    //{ PJ_STUN_SC_UNKNOWN_USERNAME,        "Unknown Username"},
    { PJ_STUN_SC_ALLOCATION_MISMATCH,       "Allocation Mismatch"},
    { PJ_STUN_SC_STALE_NONCE,               "Stale Nonce"},
    { PJ_STUN_SC_TRANSITIONING,             "Active Destination Already Set"},
    { PJ_STUN_SC_WRONG_CREDENTIALS,         "Wrong Credentials"},
    { PJ_STUN_SC_UNSUPP_TRANSPORT_PROTO,    "Unsupported Transport Protocol"},
    { PJ_STUN_SC_OPER_TCP_ONLY,             "Operation for TCP Only"},
    { PJ_STUN_SC_CONNECTION_FAILURE,        "Connection Failure"},
    { PJ_STUN_SC_CONNECTION_TIMEOUT,        "Connection Timeout"},
    { PJ_STUN_SC_ALLOCATION_QUOTA_REACHED,  "Allocation Quota Reached"},
    { PJ_STUN_SC_ROLE_CONFLICT,             "Role Conflict"},
    { PJ_STUN_SC_SERVER_ERROR,              "Server Error"},
    { PJ_STUN_SC_INSUFFICIENT_CAPACITY,     "Insufficient Capacity"},
    { PJ_STUN_SC_GLOBAL_FAILURE,            "Global Failure"}
};



struct attr_desc
{
    const char   *name;
    pj_status_t (*decode_attr)(pj_pool_t *pool, const pj_uint8_t *buf, 
                               const pj_stun_msg_hdr *msghdr, void **p_attr);
    pj_status_t (*encode_attr)(const void *a, pj_uint8_t *buf, 
                               unsigned len, const pj_stun_msg_hdr *msghdr,
                               unsigned *printed);
    void*       (*clone_attr)(pj_pool_t *pool, const void *src);
};

static pj_status_t decode_sockaddr_attr(pj_pool_t *pool, 
                                        const pj_uint8_t *buf, 
                                        const pj_stun_msg_hdr *msghdr,
                                        void **p_attr);
static pj_status_t decode_xored_sockaddr_attr(pj_pool_t *pool, 
                                              const pj_uint8_t *buf, 
                                              const pj_stun_msg_hdr *msghdr, 
                                              void **p_attr);
static pj_status_t encode_sockaddr_attr(const void *a, pj_uint8_t *buf, 
                                        unsigned len, 
                                        const pj_stun_msg_hdr *msghdr,
                                        unsigned *printed);
static void*       clone_sockaddr_attr(pj_pool_t *pool, const void *src);
static pj_status_t decode_string_attr(pj_pool_t *pool, 
                                      const pj_uint8_t *buf, 
                                      const pj_stun_msg_hdr *msghdr, 
                                      void **p_attr);
static pj_status_t encode_string_attr(const void *a, pj_uint8_t *buf, 
                                      unsigned len, 
                                      const pj_stun_msg_hdr *msghdr,
                                      unsigned *printed);
static void*       clone_string_attr(pj_pool_t *pool, const void *src);
static pj_status_t decode_msgint_attr(pj_pool_t *pool, 
                                      const pj_uint8_t *buf,
                                      const pj_stun_msg_hdr *msghdr, 
                                      void **p_attr);
static pj_status_t encode_msgint_attr(const void *a, pj_uint8_t *buf, 
                                      unsigned len, 
                                      const pj_stun_msg_hdr *msghdr,
                                      unsigned *printed);
static void*       clone_msgint_attr(pj_pool_t *pool, const void *src);
static pj_status_t decode_errcode_attr(pj_pool_t *pool, 
                                       const pj_uint8_t *buf,
                                       const pj_stun_msg_hdr *msghdr, 
                                       void **p_attr);
static pj_status_t encode_errcode_attr(const void *a, pj_uint8_t *buf, 
                                       unsigned len, 
                                       const pj_stun_msg_hdr *msghdr,
                                       unsigned *printed);
static void*       clone_errcode_attr(pj_pool_t *pool, const void *src);
static pj_status_t decode_unknown_attr(pj_pool_t *pool, 
                                       const pj_uint8_t *buf, 
                                       const pj_stun_msg_hdr *msghdr, 
                                       void **p_attr);
static pj_status_t encode_unknown_attr(const void *a, pj_uint8_t *buf, 
                                       unsigned len, 
                                       const pj_stun_msg_hdr *msghdr,
                                       unsigned *printed);
static void*       clone_unknown_attr(pj_pool_t *pool, const void *src);
static pj_status_t decode_uint_attr(pj_pool_t *pool, 
                                    const pj_uint8_t *buf, 
                                    const pj_stun_msg_hdr *msghdr, 
                                    void **p_attr);
static pj_status_t encode_uint_attr(const void *a, pj_uint8_t *buf, 
                                    unsigned len, 
                                    const pj_stun_msg_hdr *msghdr,
                                    unsigned *printed);
static void*       clone_uint_attr(pj_pool_t *pool, const void *src);
static pj_status_t decode_uint64_attr(pj_pool_t *pool, 
                                      const pj_uint8_t *buf, 
                                      const pj_stun_msg_hdr *msghdr, 
                                      void **p_attr);
static pj_status_t encode_uint64_attr(const void *a, pj_uint8_t *buf, 
                                      unsigned len, 
                                      const pj_stun_msg_hdr *msghdr,
                                      unsigned *printed);
static void*       clone_uint64_attr(pj_pool_t *pool, const void *src);
static pj_status_t decode_binary_attr(pj_pool_t *pool, 
                                      const pj_uint8_t *buf,
                                      const pj_stun_msg_hdr *msghdr, 
                                      void **p_attr);
static pj_status_t encode_binary_attr(const void *a, pj_uint8_t *buf, 
                                      unsigned len, 
                                      const pj_stun_msg_hdr *msghdr,
                                      unsigned *printed);
static void*       clone_binary_attr(pj_pool_t *pool, const void *src);
static pj_status_t decode_empty_attr(pj_pool_t *pool, 
                                     const pj_uint8_t *buf, 
                                     const pj_stun_msg_hdr *msghdr, 
                                     void **p_attr);
static pj_status_t encode_empty_attr(const void *a, pj_uint8_t *buf, 
                                     unsigned len, 
                                     const pj_stun_msg_hdr *msghdr,
                                     unsigned *printed);
static void*       clone_empty_attr(pj_pool_t *pool, const void *src);

static struct attr_desc mandatory_attr_desc[] = 
{
    {
        /* type zero */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* PJ_STUN_ATTR_MAPPED_ADDR, */
        "MAPPED-ADDRESS",
        &decode_sockaddr_attr,
        &encode_sockaddr_attr,
        &clone_sockaddr_attr
    },
    {
        /* PJ_STUN_ATTR_RESPONSE_ADDR, */
        "RESPONSE-ADDRESS",
        &decode_sockaddr_attr,
        &encode_sockaddr_attr,
        &clone_sockaddr_attr
    },
    {
        /* PJ_STUN_ATTR_CHANGE_REQUEST, */
        "CHANGE-REQUEST",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* PJ_STUN_ATTR_SOURCE_ADDR, */
        "SOURCE-ADDRESS",
        &decode_sockaddr_attr,
        &encode_sockaddr_attr,
        &clone_sockaddr_attr
    },
    {
        /* PJ_STUN_ATTR_CHANGED_ADDR, */
        "CHANGED-ADDRESS",
        &decode_sockaddr_attr,
        &encode_sockaddr_attr,
        &clone_sockaddr_attr
    },
    {
        /* PJ_STUN_ATTR_USERNAME, */
        "USERNAME",
        &decode_string_attr,
        &encode_string_attr,
        &clone_string_attr
    },
    {
        /* PJ_STUN_ATTR_PASSWORD, */
        "PASSWORD",
        &decode_string_attr,
        &encode_string_attr,
        &clone_string_attr
    },
    {
        /* PJ_STUN_ATTR_MESSAGE_INTEGRITY, */
        "MESSAGE-INTEGRITY",
        &decode_msgint_attr,
        &encode_msgint_attr,
        &clone_msgint_attr
    },
    {
        /* PJ_STUN_ATTR_ERROR_CODE, */
        "ERROR-CODE",
        &decode_errcode_attr,
        &encode_errcode_attr,
        &clone_errcode_attr
    },
    {
        /* PJ_STUN_ATTR_UNKNOWN_ATTRIBUTES, */
        "UNKNOWN-ATTRIBUTES",
        &decode_unknown_attr,
        &encode_unknown_attr,
        &clone_unknown_attr
    },
    {
        /* PJ_STUN_ATTR_REFLECTED_FROM, */
        "REFLECTED-FROM",
        &decode_sockaddr_attr,
        &encode_sockaddr_attr,
        &clone_sockaddr_attr
    },
    {
        /* PJ_STUN_ATTR_CHANNEL_NUMBER (0x000C) */
        "CHANNEL-NUMBER",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* PJ_STUN_ATTR_LIFETIME, */
        "LIFETIME",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* ID 0x000E is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* PJ_STUN_ATTR_MAGIC_COOKIE */
        "MAGIC-COOKIE",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* PJ_STUN_ATTR_BANDWIDTH, */
        "BANDWIDTH",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* ID 0x0011 is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* PJ_STUN_ATTR_XOR_PEER_ADDRESS, */
        "XOR-PEER-ADDRESS",
        &decode_xored_sockaddr_attr,
        &encode_sockaddr_attr,
        &clone_sockaddr_attr
    },
    {
        /* PJ_STUN_ATTR_DATA, */
        "DATA",
        &decode_binary_attr,
        &encode_binary_attr,
        &clone_binary_attr
    },
    {
        /* PJ_STUN_ATTR_REALM, */
        "REALM",
        &decode_string_attr,
        &encode_string_attr,
        &clone_string_attr
    },
    {
        /* PJ_STUN_ATTR_NONCE, */
        "NONCE",
        &decode_string_attr,
        &encode_string_attr,
        &clone_string_attr
    },
    {
        /* PJ_STUN_ATTR_XOR_RELAYED_ADDR, */
        "XOR-RELAYED-ADDRESS",
        &decode_xored_sockaddr_attr,
        &encode_sockaddr_attr,
        &clone_sockaddr_attr
    },
    {
        /* PJ_STUN_ATTR_REQUESTED_ADDR_FAMILY, */
        "REQUESTED-ADDRESS-FAMILY",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* PJ_STUN_ATTR_EVEN_PORT, */
        "EVEN-PORT",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* PJ_STUN_ATTR_REQUESTED_TRANSPORT, */
        "REQUESTED-TRANSPORT",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* PJ_STUN_ATTR_DONT_FRAGMENT */
        "DONT-FRAGMENT",
        &decode_empty_attr,
        &encode_empty_attr,
        &clone_empty_attr
    },
    {
        /* ID 0x001B is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* ID 0x001C is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* ID 0x001D is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* ID 0x001E is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* ID 0x001F is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* PJ_STUN_ATTR_XOR_MAPPED_ADDRESS, */
        "XOR-MAPPED-ADDRESS",
        &decode_xored_sockaddr_attr,
        &encode_sockaddr_attr,
        &clone_sockaddr_attr
    },
    {
        /* PJ_STUN_ATTR_TIMER_VAL, */
        "TIMER-VAL",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* PJ_STUN_ATTR_RESERVATION_TOKEN, */
        "RESERVATION-TOKEN",
        &decode_uint64_attr,
        &encode_uint64_attr,
        &clone_uint64_attr
    },
    {
        /* PJ_STUN_ATTR_XOR_REFLECTED_FROM, */
        "XOR-REFLECTED-FROM",
        &decode_xored_sockaddr_attr,
        &encode_sockaddr_attr,
        &clone_sockaddr_attr
    },
    {
        /* PJ_STUN_ATTR_PRIORITY, */
        "PRIORITY",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* PJ_STUN_ATTR_USE_CANDIDATE, */
        "USE-CANDIDATE",
        &decode_empty_attr,
        &encode_empty_attr,
        &clone_empty_attr
    },
    {
        /* ID 0x0026 is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* ID 0x0027 is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* ID 0x0028 is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* ID 0x0029 is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* PJ_STUN_ATTR_CONNECTION_ID, */
        "CONNECTION-ID",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* ID 0x002b is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* ID 0x002c is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* ID 0x002d is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* ID 0x002e is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* ID 0x002f is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* PJ_STUN_ATTR_ICMP, */
        "ICMP",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },

    /* Sentinel */
    {
        /* PJ_STUN_ATTR_END_MANDATORY_ATTR */
        NULL,
        NULL,
        NULL,
        NULL
    }
};

static struct attr_desc extended_attr_desc[] =
{
    {
        /* ID 0x8021 is not assigned */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* PJ_STUN_ATTR_SOFTWARE, */
        "SOFTWARE",
        &decode_string_attr,
        &encode_string_attr,
        &clone_string_attr
    },
    {
        /* PJ_STUN_ATTR_ALTERNATE_SERVER, */
        "ALTERNATE-SERVER",
        &decode_sockaddr_attr,
        &encode_sockaddr_attr,
        &clone_sockaddr_attr
    },
    {
        /* PJ_STUN_ATTR_REFRESH_INTERVAL, */
        "REFRESH-INTERVAL",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* ID 0x8025 is not assigned*/
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* PADDING, 0x8026 */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* CACHE-TIMEOUT, 0x8027 */
        NULL,
        NULL,
        NULL,
        NULL
    },
    {
        /* PJ_STUN_ATTR_FINGERPRINT, */
        "FINGERPRINT",
        &decode_uint_attr,
        &encode_uint_attr,
        &clone_uint_attr
    },
    {
        /* PJ_STUN_ATTR_ICE_CONTROLLED, */
        "ICE-CONTROLLED",
        &decode_uint64_attr,
        &encode_uint64_attr,
        &clone_uint64_attr
    },
    {
        /* PJ_STUN_ATTR_ICE_CONTROLLING, */
        "ICE-CONTROLLING",
        &decode_uint64_attr,
        &encode_uint64_attr,
        &clone_uint64_attr
    }
};



/*
 * Get STUN message type name.
 */
PJ_DEF(const char*) pj_stun_get_method_name(unsigned msg_type)
{
    unsigned method = PJ_STUN_GET_METHOD(msg_type);

    if (method >= PJ_ARRAY_SIZE(stun_method_names))
        return "???";

    return stun_method_names[method];
}


/*
 * Get STUN message class name.
 */
PJ_DEF(const char*) pj_stun_get_class_name(unsigned msg_type)
{
    if (PJ_STUN_IS_REQUEST(msg_type))
        return "request";
    else if (PJ_STUN_IS_SUCCESS_RESPONSE(msg_type))
        return "success response";
    else if (PJ_STUN_IS_ERROR_RESPONSE(msg_type))
        return "error response";
    else if (PJ_STUN_IS_INDICATION(msg_type))
        return "indication";
    else
        return "???";
}


static const struct attr_desc *find_attr_desc(unsigned attr_type)
{
    struct attr_desc *desc;

    /* Check that attr_desc array is valid */
    pj_assert(PJ_ARRAY_SIZE(mandatory_attr_desc)==
              PJ_STUN_ATTR_END_MANDATORY_ATTR+1);
    pj_assert(mandatory_attr_desc[PJ_STUN_ATTR_END_MANDATORY_ATTR].decode_attr
              == NULL);
    pj_assert(mandatory_attr_desc[PJ_STUN_ATTR_USE_CANDIDATE].decode_attr 
              == &decode_empty_attr);
    pj_assert(PJ_ARRAY_SIZE(extended_attr_desc) ==
              PJ_STUN_ATTR_END_EXTENDED_ATTR-PJ_STUN_ATTR_START_EXTENDED_ATTR);

    if (attr_type < PJ_STUN_ATTR_END_MANDATORY_ATTR)
        desc = &mandatory_attr_desc[attr_type];
    else if (attr_type >= PJ_STUN_ATTR_START_EXTENDED_ATTR &&
             attr_type < PJ_STUN_ATTR_END_EXTENDED_ATTR)
        desc = &extended_attr_desc[attr_type-PJ_STUN_ATTR_START_EXTENDED_ATTR];
    else
        return NULL;

    return desc->decode_attr == NULL ? NULL : desc;
}


/*
 * Get STUN attribute name.
 */
PJ_DEF(const char*) pj_stun_get_attr_name(unsigned attr_type)
{
    const struct attr_desc *attr_desc;

    attr_desc = find_attr_desc(attr_type);
    if (!attr_desc || attr_desc->name==NULL)
        return "???";

    return attr_desc->name;
}


/**
 * Get STUN standard reason phrase for the specified error code.
 */
PJ_DEF(pj_str_t) pj_stun_get_err_reason(int err_code)
{
#if 0
    /* Find error using linear search */
    unsigned i;

    for (i=0; i<PJ_ARRAY_SIZE(stun_err_msg_map); ++i) {
        if (stun_err_msg_map[i].err_code == err_code)
            return pj_str((char*)stun_err_msg_map[i].err_msg);
    }
    return pj_str(NULL);
#else
    /* Find error message using binary search */
    int first = 0;
    int n = PJ_ARRAY_SIZE(stun_err_msg_map);

    while (n > 0) {
        int half = n/2;
        int mid = first + half;

        if (stun_err_msg_map[mid].err_code < err_code) {
            first = mid+1;
            n -= (half+1);
        } else if (stun_err_msg_map[mid].err_code > err_code) {
            n = half;
        } else {
            first = mid;
            break;
        }
    }


    if (stun_err_msg_map[first].err_code == err_code) {
        return pj_str((char*)stun_err_msg_map[first].err_msg);
    } else {
        return pj_str(NULL);
    }
#endif
}


/*
 * Set padding character.
 */
PJ_DEF(int) pj_stun_set_padding_char(int chr)
{
    int old_pad = padding_char;
    padding_char = chr;
    return old_pad;
}


//////////////////////////////////////////////////////////////////////////////


#define INIT_ATTR(a,t,l)    (a)->hdr.type=(pj_uint16_t)(t), \
                            (a)->hdr.length=(pj_uint16_t)(l)
#define ATTR_HDR_LEN        sizeof(pj_stun_attr_hdr)

static pj_uint16_t GETVAL16H(const pj_uint8_t *buf, unsigned pos)
{
    return (pj_uint16_t) (((pj_uint16_t)buf[pos + 0] << 8) | \
                          ((pj_uint16_t)buf[pos + 1] << 0));
}

/*unused PJ_INLINE(pj_uint16_t) GETVAL16N(const pj_uint8_t *buf, unsigned pos)
{
    return pj_htons(GETVAL16H(buf,pos));
}*/

static void PUTVAL16H(pj_uint8_t *buf, unsigned pos, pj_uint16_t hval)
{
    buf[pos+0] = (pj_uint8_t) ((hval & 0xFF00) >> 8);
    buf[pos+1] = (pj_uint8_t) ((hval & 0x00FF) >> 0);
}

PJ_INLINE(pj_uint32_t) GETVAL32H(const pj_uint8_t *buf, unsigned pos)
{
    return (pj_uint32_t) (((pj_uint32_t)buf[pos + 0] << 24UL) | \
                          ((pj_uint32_t)buf[pos + 1] << 16UL) | \
                          ((pj_uint32_t)buf[pos + 2] <<  8UL) | \
                          ((pj_uint32_t)buf[pos + 3] <<  0UL));
}

/*unused PJ_INLINE(pj_uint32_t) GETVAL32N(const pj_uint8_t *buf, unsigned pos)
{
    return pj_htonl(GETVAL32H(buf,pos));
}*/

static void PUTVAL32H(pj_uint8_t *buf, unsigned pos, pj_uint32_t hval)
{
    buf[pos+0] = (pj_uint8_t) ((hval & 0xFF000000UL) >> 24);
    buf[pos+1] = (pj_uint8_t) ((hval & 0x00FF0000UL) >> 16);
    buf[pos+2] = (pj_uint8_t) ((hval & 0x0000FF00UL) >>  8);
    buf[pos+3] = (pj_uint8_t) ((hval & 0x000000FFUL) >>  0);
}

static void GETVAL64H(const pj_uint8_t *buf, unsigned pos, pj_timestamp *ts)
{
    ts->u32.hi = GETVAL32H(buf, pos);
    ts->u32.lo = GETVAL32H(buf, pos+4);
}

static void PUTVAL64H(pj_uint8_t *buf, unsigned pos, const pj_timestamp *ts)
{
    PUTVAL32H(buf, pos, ts->u32.hi);
    PUTVAL32H(buf, pos+4, ts->u32.lo);
}


static void GETATTRHDR(const pj_uint8_t *buf, pj_stun_attr_hdr *hdr)
{
    hdr->type = GETVAL16H(buf, 0);
    hdr->length = GETVAL16H(buf, 2);
}

//////////////////////////////////////////////////////////////////////////////
/*
 * STUN generic IP address container
 */
#define STUN_GENERIC_IPV4_ADDR_LEN      8
#define STUN_GENERIC_IPV6_ADDR_LEN      20

/*
 * Init sockaddr attr
 */
PJ_DEF(pj_status_t) pj_stun_sockaddr_attr_init( pj_stun_sockaddr_attr *attr,
                                                int attr_type, 
                                                pj_bool_t xor_ed,
                                                const pj_sockaddr_t *addr,
                                                unsigned addr_len)
{
    unsigned attr_len;

    PJ_ASSERT_RETURN(attr && addr_len && addr, PJ_EINVAL);
    PJ_ASSERT_RETURN(addr_len == sizeof(pj_sockaddr_in) ||
                     addr_len == sizeof(pj_sockaddr_in6), PJ_EINVAL);

    attr_len = pj_sockaddr_get_addr_len(addr) + 4;
    INIT_ATTR(attr, attr_type, attr_len);

    pj_memcpy(&attr->sockaddr, addr, addr_len);
    attr->xor_ed = xor_ed;

    return PJ_SUCCESS;
}


/*
 * Create a generic STUN IP address attribute for IPv4 address.
 */
PJ_DEF(pj_status_t) pj_stun_sockaddr_attr_create(pj_pool_t *pool,
                                                 int attr_type,
                                                 pj_bool_t xor_ed,
                                                 const pj_sockaddr_t *addr,
                                                 unsigned addr_len,
                                                 pj_stun_sockaddr_attr **p_attr)
{
    pj_stun_sockaddr_attr *attr;

    PJ_ASSERT_RETURN(pool && p_attr, PJ_EINVAL);
    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_sockaddr_attr);
    *p_attr = attr;
    return pj_stun_sockaddr_attr_init(attr, attr_type, xor_ed, 
                                      addr, addr_len);
}


/*
 * Create and add generic STUN IP address attribute to a STUN message.
 */
PJ_DEF(pj_status_t) pj_stun_msg_add_sockaddr_attr(pj_pool_t *pool,
                                                  pj_stun_msg *msg,
                                                  int attr_type, 
                                                  pj_bool_t xor_ed,
                                                  const pj_sockaddr_t *addr,
                                                  unsigned addr_len)
{
    pj_stun_sockaddr_attr *attr;
    pj_status_t status;

    status = pj_stun_sockaddr_attr_create(pool, attr_type, xor_ed,
                                                 addr, addr_len, &attr);
    if (status != PJ_SUCCESS)
        return status;

    return pj_stun_msg_add_attr(msg, &attr->hdr);
}

static pj_status_t decode_sockaddr_attr(pj_pool_t *pool, 
                                        const pj_uint8_t *buf, 
                                        const pj_stun_msg_hdr *msghdr, 
                                        void **p_attr)
{
    pj_stun_sockaddr_attr *attr;
    int af;
    unsigned addr_len;
    pj_uint32_t val;

    PJ_CHECK_STACK();
    
    PJ_UNUSED_ARG(msghdr);

    /* Create the attribute */
    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_sockaddr_attr);
    GETATTRHDR(buf, &attr->hdr);

    /* Check that the attribute length is valid */
    if (attr->hdr.length != STUN_GENERIC_IPV4_ADDR_LEN &&
        attr->hdr.length != STUN_GENERIC_IPV6_ADDR_LEN)
    {
        return PJNATH_ESTUNINATTRLEN;
    }

    /* Check address family */
    val = *(pj_uint8_t*)(buf + ATTR_HDR_LEN + 1);

    /* Check address family is valid */
    if (val == 1) {
        if (attr->hdr.length != STUN_GENERIC_IPV4_ADDR_LEN)
            return PJNATH_ESTUNINATTRLEN;
        af = pj_AF_INET();
        addr_len = 4;
    } else if (val == 2) {
        if (attr->hdr.length != STUN_GENERIC_IPV6_ADDR_LEN)
            return PJNATH_ESTUNINATTRLEN;
        af = pj_AF_INET6();
        addr_len = 16;
    } else {
        /* Invalid address family */
        return PJNATH_EINVAF;
    }

    /* Get port and address */
    pj_sockaddr_init(af, &attr->sockaddr, NULL, 0);
    pj_sockaddr_set_port(&attr->sockaddr, 
                         GETVAL16H(buf, ATTR_HDR_LEN+2));
    pj_memcpy(pj_sockaddr_get_addr(&attr->sockaddr),
              buf+ATTR_HDR_LEN+4,
              addr_len);

    /* Done */
    *p_attr = (void*)attr;

    return PJ_SUCCESS;
}


static pj_status_t decode_xored_sockaddr_attr(pj_pool_t *pool, 
                                              const pj_uint8_t *buf, 
                                              const pj_stun_msg_hdr *msghdr, 
                                              void **p_attr)
{
    pj_stun_sockaddr_attr *attr;
    pj_status_t status;

    status = decode_sockaddr_attr(pool, buf, msghdr, p_attr);
    if (status != PJ_SUCCESS)
        return status;

    attr = *(pj_stun_sockaddr_attr**)p_attr;

    attr->xor_ed = PJ_TRUE;

    if (attr->sockaddr.addr.sa_family == pj_AF_INET()) {
        attr->sockaddr.ipv4.sin_port ^= pj_htons(PJ_STUN_MAGIC >> 16);
        attr->sockaddr.ipv4.sin_addr.s_addr ^= pj_htonl(PJ_STUN_MAGIC);
    } else if (attr->sockaddr.addr.sa_family == pj_AF_INET6()) {
        unsigned i;
        pj_uint8_t *dst = (pj_uint8_t*) &attr->sockaddr.ipv6.sin6_addr;
        pj_uint32_t magic = pj_htonl(PJ_STUN_MAGIC);

        attr->sockaddr.ipv6.sin6_port ^= pj_htons(PJ_STUN_MAGIC >> 16);

        /* If the IP address family is IPv6, X-Address is computed by
         * taking the mapped IP address in host byte order, XOR'ing it
         * with the concatenation of the magic cookie and the 96-bit 
         * transaction ID, and converting the result to network byte 
         * order.
         */
        for (i=0; i<4; ++i) {
            dst[i] ^= ((const pj_uint8_t*)&magic)[i];
        }
        pj_assert(sizeof(msghdr->tsx_id[0]) == 1);
        for (i=0; i<12; ++i) {
            dst[i+4] ^= msghdr->tsx_id[i];
        }

    } else {
        return PJNATH_EINVAF;
    }

    /* Done */
    *p_attr = attr;

    return PJ_SUCCESS;
}


static pj_status_t encode_sockaddr_attr(const void *a, pj_uint8_t *buf, 
                                        unsigned len, 
                                        const pj_stun_msg_hdr *msghdr,
                                        unsigned *printed)
{
    pj_uint8_t *start_buf = buf;
    const pj_stun_sockaddr_attr *ca = 
        (const pj_stun_sockaddr_attr *)a;

    PJ_CHECK_STACK();
    
    /* Common: attribute type */
    PUTVAL16H(buf, 0, ca->hdr.type);

    if (ca->sockaddr.addr.sa_family == pj_AF_INET()) {
        enum {
            ATTR_LEN = ATTR_HDR_LEN + STUN_GENERIC_IPV4_ADDR_LEN
        };

        if (len < ATTR_LEN) 
            return PJ_ETOOSMALL;

        /* attribute len */
        PUTVAL16H(buf, 2, STUN_GENERIC_IPV4_ADDR_LEN);
        buf += ATTR_HDR_LEN;
    
        /* Ignored */
        *buf++ = '\0';

        /* Address family, 1 for IPv4 */
        *buf++ = 1;

        /* IPv4 address */
        if (ca->xor_ed) {
            pj_uint32_t addr;
            pj_uint16_t port;

            addr = ca->sockaddr.ipv4.sin_addr.s_addr;
            port = ca->sockaddr.ipv4.sin_port;

            port ^= pj_htons(PJ_STUN_MAGIC >> 16);
            addr ^= pj_htonl(PJ_STUN_MAGIC);

            /* Port */
            pj_memcpy(buf, &port, 2);
            buf += 2;

            /* Address */
            pj_memcpy(buf, &addr, 4);
            buf += 4;

        } else {
            /* Port */
            pj_memcpy(buf, &ca->sockaddr.ipv4.sin_port, 2);
            buf += 2;

            /* Address */
            pj_memcpy(buf, &ca->sockaddr.ipv4.sin_addr, 4);
            buf += 4;
        }

        pj_assert(buf - start_buf == ATTR_LEN);

    } else if (ca->sockaddr.addr.sa_family == pj_AF_INET6()) {
        /* IPv6 address */
        enum {
            ATTR_LEN = ATTR_HDR_LEN + STUN_GENERIC_IPV6_ADDR_LEN
        };

        if (len < ATTR_LEN) 
            return PJ_ETOOSMALL;

        /* attribute len */
        PUTVAL16H(buf, 2, STUN_GENERIC_IPV6_ADDR_LEN);
        buf += ATTR_HDR_LEN;
    
        /* Ignored */
        *buf++ = '\0';

        /* Address family, 2 for IPv6 */
        *buf++ = 2;

        /* IPv6 address */
        if (ca->xor_ed) {
            unsigned i;
            pj_uint8_t *dst;
            const pj_uint8_t *src;
            pj_uint32_t magic = pj_htonl(PJ_STUN_MAGIC);
            pj_uint16_t port = ca->sockaddr.ipv6.sin6_port;

            /* Port */
            port ^= pj_htons(PJ_STUN_MAGIC >> 16);
            pj_memcpy(buf, &port, 2);
            buf += 2;

            /* Address */
            dst = buf;
            src = (const pj_uint8_t*) &ca->sockaddr.ipv6.sin6_addr;
            for (i=0; i<4; ++i) {
                dst[i] = (pj_uint8_t)(src[i] ^ ((const pj_uint8_t*)&magic)[i]);
            }
            pj_assert(sizeof(msghdr->tsx_id[0]) == 1);
            for (i=0; i<12; ++i) {
                dst[i+4] = (pj_uint8_t)(src[i+4] ^ msghdr->tsx_id[i]);
            }

            buf += 16;

        } else {
            /* Port */
            pj_memcpy(buf, &ca->sockaddr.ipv6.sin6_port, 2);
            buf += 2;

            /* Address */
            pj_memcpy(buf, &ca->sockaddr.ipv6.sin6_addr, 16);
            buf += 16;
        }

        pj_assert(buf - start_buf == ATTR_LEN);

    } else {
        return PJNATH_EINVAF;
    }

    /* Done */
    *printed = (unsigned)(buf - start_buf);

    return PJ_SUCCESS;
}


static void* clone_sockaddr_attr(pj_pool_t *pool, const void *src)
{
    pj_stun_sockaddr_attr *dst = PJ_POOL_ALLOC_T(pool, pj_stun_sockaddr_attr);
    pj_memcpy(dst, src, sizeof(pj_stun_sockaddr_attr));
    return (void*)dst;
}

//////////////////////////////////////////////////////////////////////////////
/*
 * STUN generic string attribute
 */

/*
 * Initialize a STUN generic string attribute.
 */
PJ_DEF(pj_status_t) pj_stun_string_attr_init( pj_stun_string_attr *attr,
                                              pj_pool_t *pool,
                                              int attr_type,
                                              const pj_str_t *value)
{
    if (value && value->slen) {
        INIT_ATTR(attr, attr_type, value->slen);
        attr->value.slen = value->slen;
        pj_strdup(pool, &attr->value, value);
    } else {
        INIT_ATTR(attr, attr_type, 0);
    }
    return PJ_SUCCESS;
}


/*
 * Create a STUN generic string attribute.
 */
PJ_DEF(pj_status_t) pj_stun_string_attr_create(pj_pool_t *pool,
                                               int attr_type,
                                               const pj_str_t *value,
                                               pj_stun_string_attr **p_attr)
{
    pj_stun_string_attr *attr;

    PJ_ASSERT_RETURN(pool && value && p_attr, PJ_EINVAL);

    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_string_attr);
    *p_attr = attr;

    return pj_stun_string_attr_init(attr, pool, attr_type, value);
}


/*
 * Create and add STUN generic string attribute to the message.
 */
PJ_DEF(pj_status_t) pj_stun_msg_add_string_attr(pj_pool_t *pool,
                                                pj_stun_msg *msg,
                                                int attr_type,
                                                const pj_str_t *value)
{
    pj_stun_string_attr *attr = NULL;
    pj_status_t status;

    status = pj_stun_string_attr_create(pool, attr_type, value, 
                                                &attr);
    if (status != PJ_SUCCESS)
        return status;

    return pj_stun_msg_add_attr(msg, &attr->hdr);
}


static pj_status_t decode_string_attr(pj_pool_t *pool, 
                                      const pj_uint8_t *buf, 
                                      const pj_stun_msg_hdr *msghdr, 
                                      void **p_attr)
{
    pj_stun_string_attr *attr;
    pj_str_t value;

    PJ_UNUSED_ARG(msghdr);

    /* Create the attribute */
    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_string_attr);
    GETATTRHDR(buf, &attr->hdr);

    /* Get pointer to the string in the message */
    value.ptr = ((char*)buf + ATTR_HDR_LEN);
    value.slen = attr->hdr.length;

    /* Copy the string to the attribute */
    pj_strdup(pool, &attr->value, &value);

    /* Done */
    *p_attr = attr;

    return PJ_SUCCESS;

}


static pj_status_t encode_string_attr(const void *a, pj_uint8_t *buf, 
                                      unsigned len, 
                                      const pj_stun_msg_hdr *msghdr,
                                      unsigned *printed)
{
    const pj_stun_string_attr *ca = 
        (const pj_stun_string_attr*)a;

    PJ_CHECK_STACK();
    
    PJ_UNUSED_ARG(msghdr);

    /* Calculated total attr_len (add padding if necessary) */
    *printed = ((unsigned)ca->value.slen + ATTR_HDR_LEN + 3) & (~3);
    if (len < *printed) {
        *printed = 0;
        return PJ_ETOOSMALL;
    }

    PUTVAL16H(buf, 0, ca->hdr.type);

    /* Special treatment for SOFTWARE attribute:
     * This attribute had caused interop problem when talking to 
     * legacy RFC 3489 STUN servers, due to different "length"
     * rules with RFC 5389.
     */
    if (msghdr->magic != PJ_STUN_MAGIC ||
        ca->hdr.type == PJ_STUN_ATTR_SOFTWARE)
    {
        /* Set the length to be 4-bytes aligned so that we can
         * communicate with RFC 3489 endpoints
         */
        PUTVAL16H(buf, 2, (pj_uint16_t)((ca->value.slen + 3) & (~3)));
    } else {
        /* Use RFC 5389 rule */
        PUTVAL16H(buf, 2, (pj_uint16_t)ca->value.slen);
    }

    /* Copy the string */
    pj_memcpy(buf+ATTR_HDR_LEN, ca->value.ptr, ca->value.slen);

    /* Add padding character, if string is not 4-bytes aligned. */
    if (ca->value.slen & 0x03) {
        pj_uint8_t pad[3];
        pj_memset(pad, padding_char, sizeof(pad));
        pj_memcpy(buf+ATTR_HDR_LEN+ca->value.slen, pad,
                  4-(ca->value.slen & 0x03));
    }

    /* Done */
    return PJ_SUCCESS;
}


static void* clone_string_attr(pj_pool_t *pool, const void *src)
{
    const pj_stun_string_attr *asrc = (const pj_stun_string_attr*)src;
    pj_stun_string_attr *dst = PJ_POOL_ALLOC_T(pool, pj_stun_string_attr);

    pj_memcpy(dst, src, sizeof(pj_stun_attr_hdr));
    pj_strdup(pool, &dst->value, &asrc->value);

    return (void*)dst;
}

//////////////////////////////////////////////////////////////////////////////
/*
 * STUN empty attribute (used by USE-CANDIDATE).
 */

/*
 * Create a STUN empty attribute.
 */
PJ_DEF(pj_status_t) pj_stun_empty_attr_create(pj_pool_t *pool,
                                              int attr_type,
                                              pj_stun_empty_attr **p_attr)
{
    pj_stun_empty_attr *attr;

    PJ_ASSERT_RETURN(pool && p_attr, PJ_EINVAL);

    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_empty_attr);
    INIT_ATTR(attr, attr_type, 0);

    *p_attr = attr;

    return PJ_SUCCESS;
}


/*
 * Create STUN empty attribute and add the attribute to the message.
 */
PJ_DEF(pj_status_t) pj_stun_msg_add_empty_attr( pj_pool_t *pool,
                                                pj_stun_msg *msg,
                                                int attr_type)
{
    pj_stun_empty_attr *attr = NULL;
    pj_status_t status;

    status = pj_stun_empty_attr_create(pool, attr_type, &attr);
    if (status != PJ_SUCCESS)
        return status;

    return pj_stun_msg_add_attr(msg, &attr->hdr);
}

static pj_status_t decode_empty_attr(pj_pool_t *pool, 
                                     const pj_uint8_t *buf, 
                                     const pj_stun_msg_hdr *msghdr,
                                     void **p_attr)
{
    pj_stun_empty_attr *attr;

    PJ_UNUSED_ARG(msghdr);

    /* Check that the struct address is valid */
    pj_assert(sizeof(pj_stun_empty_attr) == ATTR_HDR_LEN);

    /* Create the attribute */
    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_empty_attr);
    GETATTRHDR(buf, &attr->hdr);

    /* Check that the attribute length is valid */
    if (attr->hdr.length != 0)
        return PJNATH_ESTUNINATTRLEN;

    /* Done */
    *p_attr = attr;

    return PJ_SUCCESS;
}


static pj_status_t encode_empty_attr(const void *a, pj_uint8_t *buf, 
                                     unsigned len, 
                                     const pj_stun_msg_hdr *msghdr,
                                     unsigned *printed)
{
    const pj_stun_empty_attr *ca = (pj_stun_empty_attr*)a;

    PJ_UNUSED_ARG(msghdr);

    if (len < ATTR_HDR_LEN) 
        return PJ_ETOOSMALL;

    PUTVAL16H(buf, 0, ca->hdr.type);
    PUTVAL16H(buf, 2, 0);

    /* Done */
    *printed = ATTR_HDR_LEN;

    return PJ_SUCCESS;
}


static void* clone_empty_attr(pj_pool_t *pool, const void *src)
{
    pj_stun_empty_attr *dst = PJ_POOL_ALLOC_T(pool, pj_stun_empty_attr);

    pj_memcpy(dst, src, sizeof(pj_stun_empty_attr));

    return (void*) dst;
}

//////////////////////////////////////////////////////////////////////////////
/*
 * STUN generic 32bit integer attribute.
 */

/*
 * Create a STUN generic 32bit value attribute.
 */
PJ_DEF(pj_status_t) pj_stun_uint_attr_create(pj_pool_t *pool,
                                             int attr_type,
                                             pj_uint32_t value,
                                             pj_stun_uint_attr **p_attr)
{
    pj_stun_uint_attr *attr;

    PJ_ASSERT_RETURN(pool && p_attr, PJ_EINVAL);

    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_uint_attr);
    INIT_ATTR(attr, attr_type, 4);
    attr->value = value;

    *p_attr = attr;

    return PJ_SUCCESS;
}

/* Create and add STUN generic 32bit value attribute to the message. */
PJ_DEF(pj_status_t) pj_stun_msg_add_uint_attr(pj_pool_t *pool,
                                              pj_stun_msg *msg,
                                              int attr_type,
                                              pj_uint32_t value)
{
    pj_stun_uint_attr *attr = NULL;
    pj_status_t status;

    status = pj_stun_uint_attr_create(pool, attr_type, value, &attr);
    if (status != PJ_SUCCESS)
        return status;

    return pj_stun_msg_add_attr(msg, &attr->hdr);
}

static pj_status_t decode_uint_attr(pj_pool_t *pool, 
                                    const pj_uint8_t *buf, 
                                    const pj_stun_msg_hdr *msghdr, 
                                    void **p_attr)
{
    pj_stun_uint_attr *attr;

    PJ_UNUSED_ARG(msghdr);

    /* Create the attribute */
    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_uint_attr);
    GETATTRHDR(buf, &attr->hdr);

    /* Check that the attribute length is valid */
    if (attr->hdr.length != 4)
        return PJNATH_ESTUNINATTRLEN;

    attr->value = GETVAL32H(buf, 4);

    /* Done */
    *p_attr = attr;

    return PJ_SUCCESS;
}


static pj_status_t encode_uint_attr(const void *a, pj_uint8_t *buf, 
                                    unsigned len, 
                                    const pj_stun_msg_hdr *msghdr,
                                    unsigned *printed)
{
    const pj_stun_uint_attr *ca = (const pj_stun_uint_attr*)a;

    PJ_CHECK_STACK();

    PJ_UNUSED_ARG(msghdr);
    
    if (len < 8) 
        return PJ_ETOOSMALL;

    PUTVAL16H(buf, 0, ca->hdr.type);
    PUTVAL16H(buf, 2, (pj_uint16_t)4);
    PUTVAL32H(buf, 4, ca->value);
    
    /* Done */
    *printed = 8;

    return PJ_SUCCESS;
}


static void* clone_uint_attr(pj_pool_t *pool, const void *src)
{
    pj_stun_uint_attr *dst = PJ_POOL_ALLOC_T(pool, pj_stun_uint_attr);

    pj_memcpy(dst, src, sizeof(pj_stun_uint_attr));

    return (void*)dst;
}

//////////////////////////////////////////////////////////////////////////////

/*
 * Create a STUN generic 64bit value attribute.
 */
PJ_DEF(pj_status_t) pj_stun_uint64_attr_create(pj_pool_t *pool,
                                               int attr_type,
                                               const pj_timestamp *value,
                                               pj_stun_uint64_attr **p_attr)
{
    pj_stun_uint64_attr *attr;

    PJ_ASSERT_RETURN(pool && p_attr, PJ_EINVAL);

    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_uint64_attr);
    INIT_ATTR(attr, attr_type, 8);

    if (value) {
        attr->value.u32.hi = value->u32.hi;
        attr->value.u32.lo = value->u32.lo;
    }

    *p_attr = attr;

    return PJ_SUCCESS;
}

/* Create and add STUN generic 64bit value attribute to the message. */
PJ_DEF(pj_status_t)  pj_stun_msg_add_uint64_attr(pj_pool_t *pool,
                                                 pj_stun_msg *msg,
                                                 int attr_type,
                                                 const pj_timestamp *value)
{
    pj_stun_uint64_attr *attr = NULL;
    pj_status_t status;

    status = pj_stun_uint64_attr_create(pool, attr_type, value, &attr);
    if (status != PJ_SUCCESS)
        return status;

    return pj_stun_msg_add_attr(msg, &attr->hdr);
}

static pj_status_t decode_uint64_attr(pj_pool_t *pool, 
                                      const pj_uint8_t *buf, 
                                      const pj_stun_msg_hdr *msghdr, 
                                      void **p_attr)
{
    pj_stun_uint64_attr *attr;

    PJ_UNUSED_ARG(msghdr);

    /* Create the attribute */
    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_uint64_attr);
    GETATTRHDR(buf, &attr->hdr);

    if (attr->hdr.length != 8)
        return PJNATH_ESTUNINATTRLEN;

    GETVAL64H(buf, 4, &attr->value);    

    /* Done */
    *p_attr = attr;

    return PJ_SUCCESS;
}


static pj_status_t encode_uint64_attr(const void *a, pj_uint8_t *buf, 
                                      unsigned len, 
                                      const pj_stun_msg_hdr *msghdr,
                                      unsigned *printed)
{
    const pj_stun_uint64_attr *ca = (const pj_stun_uint64_attr*)a;

    PJ_CHECK_STACK();

    PJ_UNUSED_ARG(msghdr);
    
    if (len < 12) 
        return PJ_ETOOSMALL;

    PUTVAL16H(buf, 0, ca->hdr.type);
    PUTVAL16H(buf, 2, (pj_uint16_t)8);
    PUTVAL64H(buf, 4, &ca->value);

    /* Done */
    *printed = 12;

    return PJ_SUCCESS;
}


static void* clone_uint64_attr(pj_pool_t *pool, const void *src)
{
    pj_stun_uint64_attr *dst = PJ_POOL_ALLOC_T(pool, pj_stun_uint64_attr);

    pj_memcpy(dst, src, sizeof(pj_stun_uint64_attr));

    return (void*)dst;
}


//////////////////////////////////////////////////////////////////////////////
/*
 * STUN MESSAGE-INTEGRITY attribute.
 */

/*
 * Create a STUN MESSAGE-INTEGRITY attribute.
 */
PJ_DEF(pj_status_t) pj_stun_msgint_attr_create(pj_pool_t *pool,
                                               pj_stun_msgint_attr **p_attr)
{
    pj_stun_msgint_attr *attr;

    PJ_ASSERT_RETURN(pool && p_attr, PJ_EINVAL);

    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_msgint_attr);
    INIT_ATTR(attr, PJ_STUN_ATTR_MESSAGE_INTEGRITY, 20);

    *p_attr = attr;

    return PJ_SUCCESS;
}


PJ_DEF(pj_status_t) pj_stun_msg_add_msgint_attr(pj_pool_t *pool,
                                                pj_stun_msg *msg)
{
    pj_stun_msgint_attr *attr = NULL;
    pj_status_t status;

    status = pj_stun_msgint_attr_create(pool, &attr);
    if (status != PJ_SUCCESS)
        return status;

    return pj_stun_msg_add_attr(msg, &attr->hdr);
}

static pj_status_t decode_msgint_attr(pj_pool_t *pool, 
                                      const pj_uint8_t *buf,
                                      const pj_stun_msg_hdr *msghdr, 
                                      void **p_attr)
{
    pj_stun_msgint_attr *attr;

    PJ_UNUSED_ARG(msghdr);

    /* Create attribute */
    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_msgint_attr);
    GETATTRHDR(buf, &attr->hdr);

    /* Check that the attribute length is valid */
    if (attr->hdr.length != 20)
        return PJNATH_ESTUNINATTRLEN;

    /* Copy hmac */
    pj_memcpy(attr->hmac, buf+4, 20);

    /* Done */
    *p_attr = attr;
    return PJ_SUCCESS;
}


static pj_status_t encode_msgint_attr(const void *a, pj_uint8_t *buf, 
                                      unsigned len, 
                                      const pj_stun_msg_hdr *msghdr,
                                      unsigned *printed)
{
    const pj_stun_msgint_attr *ca = (const pj_stun_msgint_attr*)a;

    PJ_CHECK_STACK();
    
    PJ_UNUSED_ARG(msghdr);

    if (len < 24) 
        return PJ_ETOOSMALL;

    /* Copy and convert attribute to network byte order */
    PUTVAL16H(buf, 0, ca->hdr.type);
    PUTVAL16H(buf, 2, ca->hdr.length);

    pj_memcpy(buf+4, ca->hmac, 20);

    /* Done */
    *printed = 24;

    return PJ_SUCCESS;
}


static void* clone_msgint_attr(pj_pool_t *pool, const void *src)
{
    pj_stun_msgint_attr *dst = PJ_POOL_ALLOC_T(pool, pj_stun_msgint_attr);

    pj_memcpy(dst, src, sizeof(pj_stun_msgint_attr));

    return (void*) dst;
}

//////////////////////////////////////////////////////////////////////////////
/*
 * STUN ERROR-CODE
 */

/*
 * Create a STUN ERROR-CODE attribute.
 */
PJ_DEF(pj_status_t) pj_stun_errcode_attr_create(pj_pool_t *pool,
                                                int err_code,
                                                const pj_str_t *err_reason,
                                                pj_stun_errcode_attr **p_attr)
{
    pj_stun_errcode_attr *attr;
    char err_buf[80];
    pj_str_t str;

    PJ_ASSERT_RETURN(pool && err_code && p_attr, PJ_EINVAL);

    if (err_reason == NULL) {
        str = pj_stun_get_err_reason(err_code);
        if (str.slen == 0) {
            str.slen = pj_ansi_snprintf(err_buf, sizeof(err_buf),
                                        "Unknown error %d", err_code);
            str.ptr = err_buf;
        }
        err_reason = &str;
    }

    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_errcode_attr);
    INIT_ATTR(attr, PJ_STUN_ATTR_ERROR_CODE, 4+err_reason->slen);
    attr->err_code = err_code;
    pj_strdup(pool, &attr->reason, err_reason);

    *p_attr = attr;

    return PJ_SUCCESS;
}


PJ_DEF(pj_status_t) pj_stun_msg_add_errcode_attr(pj_pool_t *pool,
                                                 pj_stun_msg *msg,
                                                 int err_code,
                                                 const pj_str_t *err_reason)
{
    pj_stun_errcode_attr *err_attr = NULL;
    pj_status_t status;

    status = pj_stun_errcode_attr_create(pool, err_code, err_reason,
                                         &err_attr);
    if (status != PJ_SUCCESS)
        return status;

    return pj_stun_msg_add_attr(msg, &err_attr->hdr);
}

static pj_status_t decode_errcode_attr(pj_pool_t *pool, 
                                       const pj_uint8_t *buf,
                                       const pj_stun_msg_hdr *msghdr, 
                                       void **p_attr)
{
    pj_stun_errcode_attr *attr;
    pj_str_t value;

    PJ_UNUSED_ARG(msghdr);

    /* Create the attribute */
    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_errcode_attr);
    GETATTRHDR(buf, &attr->hdr);

    /* Check that the attribute length is valid */
    if (attr->hdr.length < 4)
        return PJNATH_ESTUNINATTRLEN;

    attr->err_code = buf[6] * 100 + buf[7];

    /* Get pointer to the string in the message */
    value.ptr = ((char*)buf + ATTR_HDR_LEN + 4);
    value.slen = attr->hdr.length - 4;

    /* Copy the string to the attribute */
    pj_strdup(pool, &attr->reason, &value);

    /* Done */
    *p_attr = attr;

    return PJ_SUCCESS;
}


static pj_status_t encode_errcode_attr(const void *a, pj_uint8_t *buf, 
                                       unsigned len, 
                                       const pj_stun_msg_hdr *msghdr,
                                       unsigned *printed)
{
    const pj_stun_errcode_attr *ca = 
        (const pj_stun_errcode_attr*)a;

    PJ_CHECK_STACK();
    
    PJ_UNUSED_ARG(msghdr);

    if (len < ATTR_HDR_LEN + 4 + (unsigned)ca->reason.slen) 
        return PJ_ETOOSMALL;

    /* Copy and convert attribute to network byte order */
    PUTVAL16H(buf, 0, ca->hdr.type);
    PUTVAL16H(buf, 2, (pj_uint16_t)(4 + ca->reason.slen));
    PUTVAL16H(buf, 4, 0);
    buf[6] = (pj_uint8_t)(ca->err_code / 100);
    buf[7] = (pj_uint8_t)(ca->err_code % 100);

    /* Copy error string */
    pj_memcpy(buf + ATTR_HDR_LEN + 4, ca->reason.ptr, ca->reason.slen);

    /* Done */
    *printed = (ATTR_HDR_LEN + 4 + (unsigned)ca->reason.slen + 3) & (~3);

    return PJ_SUCCESS;
}


static void* clone_errcode_attr(pj_pool_t *pool, const void *src)
{
    const pj_stun_errcode_attr *asrc = (const pj_stun_errcode_attr*)src;
    pj_stun_errcode_attr *dst = PJ_POOL_ALLOC_T(pool, pj_stun_errcode_attr);

    pj_memcpy(dst, src, sizeof(pj_stun_errcode_attr));
    pj_strdup(pool, &dst->reason, &asrc->reason);

    return (void*)dst;
}

//////////////////////////////////////////////////////////////////////////////
/*
 * STUN UNKNOWN-ATTRIBUTES attribute
 */

/*
 * Create an empty instance of STUN UNKNOWN-ATTRIBUTES attribute.
 *
 * @param pool          The pool to allocate memory from.
 * @param p_attr        Pointer to receive the attribute.
 *
 * @return              PJ_SUCCESS on success or the appropriate error code.
 */
PJ_DEF(pj_status_t) pj_stun_unknown_attr_create(pj_pool_t *pool,
                                                unsigned attr_cnt,
                                                const pj_uint16_t attr_array[],
                                                pj_stun_unknown_attr **p_attr)
{
    pj_stun_unknown_attr *attr;
    unsigned i;

    PJ_ASSERT_RETURN(pool && attr_cnt < PJ_STUN_MAX_ATTR && p_attr, PJ_EINVAL);

    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_unknown_attr);
    INIT_ATTR(attr, PJ_STUN_ATTR_UNKNOWN_ATTRIBUTES, attr_cnt * 2);

    attr->attr_count = attr_cnt;
    for (i=0; i<attr_cnt; ++i) {
        attr->attrs[i] = attr_array[i];
    }

    /* If the number of unknown attributes is an odd number, one of the
     * attributes MUST be repeated in the list.
     */
    /* No longer necessary
    if ((attr_cnt & 0x01)) {
        attr->attrs[attr_cnt] = attr_array[attr_cnt-1];
    }
    */

    *p_attr = attr;

    return PJ_SUCCESS;
}


/* Create and add STUN UNKNOWN-ATTRIBUTES attribute to the message. */
PJ_DEF(pj_status_t) pj_stun_msg_add_unknown_attr(pj_pool_t *pool,
                                                 pj_stun_msg *msg,
                                                 unsigned attr_cnt,
                                                 const pj_uint16_t attr_type[])
{
    pj_stun_unknown_attr *attr = NULL;
    pj_status_t status;

    status = pj_stun_unknown_attr_create(pool, attr_cnt, attr_type, &attr);
    if (status != PJ_SUCCESS)
        return status;

    return pj_stun_msg_add_attr(msg, &attr->hdr);
}

static pj_status_t decode_unknown_attr(pj_pool_t *pool, 
                                       const pj_uint8_t *buf, 
                                       const pj_stun_msg_hdr *msghdr, 
                                       void **p_attr)
{
    pj_stun_unknown_attr *attr;
    const pj_uint16_t *punk_attr;
    unsigned i;

    PJ_UNUSED_ARG(msghdr);

    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_unknown_attr);
    GETATTRHDR(buf, &attr->hdr);
 
    attr->attr_count = (attr->hdr.length >> 1);
    if (attr->attr_count > PJ_STUN_MAX_ATTR)
        return PJ_ETOOMANY;

    punk_attr = (const pj_uint16_t*)(buf + ATTR_HDR_LEN);
    for (i=0; i<attr->attr_count; ++i) {
        attr->attrs[i] = pj_ntohs(punk_attr[i]);
    }

    /* Done */
    *p_attr = attr;

    return PJ_SUCCESS;
}


static pj_status_t encode_unknown_attr(const void *a, pj_uint8_t *buf, 
                                       unsigned len, 
                                       const pj_stun_msg_hdr *msghdr,
                                       unsigned *printed)
{
    const pj_stun_unknown_attr *ca = (const pj_stun_unknown_attr*) a;
    pj_uint16_t *dst_unk_attr;
    unsigned i;

    PJ_CHECK_STACK();
    
    PJ_UNUSED_ARG(msghdr);

    /* Check that buffer is enough */
    if (len < ATTR_HDR_LEN + (ca->attr_count << 1))
        return PJ_ETOOSMALL;

    PUTVAL16H(buf, 0, ca->hdr.type);
    PUTVAL16H(buf, 2, (pj_uint16_t)(ca->attr_count << 1));

    /* Copy individual attribute */
    dst_unk_attr = (pj_uint16_t*)(buf + ATTR_HDR_LEN);
    for (i=0; i < ca->attr_count; ++i, ++dst_unk_attr) {
        *dst_unk_attr = pj_htons(ca->attrs[i]);
    }

    /* Done */
    *printed = (ATTR_HDR_LEN + (ca->attr_count << 1) + 3) & (~3);

    return PJ_SUCCESS;
}


static void* clone_unknown_attr(pj_pool_t *pool, const void *src)
{
    pj_stun_unknown_attr *dst = PJ_POOL_ALLOC_T(pool, pj_stun_unknown_attr);

    pj_memcpy(dst, src, sizeof(pj_stun_unknown_attr));
    
    return (void*)dst;
}

//////////////////////////////////////////////////////////////////////////////
/*
 * STUN generic binary attribute
 */

/*
 * Initialize STUN binary attribute.
 */
PJ_DEF(pj_status_t) pj_stun_binary_attr_init( pj_stun_binary_attr *attr,
                                              pj_pool_t *pool,
                                              int attr_type,
                                              const pj_uint8_t *data,
                                              unsigned length)
{
    PJ_ASSERT_RETURN(attr_type, PJ_EINVAL);

    INIT_ATTR(attr, attr_type, length);

    attr->magic = PJ_STUN_MAGIC;

    if (data && length) {
        attr->length = length;
        attr->data = (pj_uint8_t*) pj_pool_alloc(pool, length);
        pj_memcpy(attr->data, data, length);
    } else {
        attr->data = NULL;
        attr->length = 0;
    }

    return PJ_SUCCESS;
}


/*
 * Create a blank binary attribute.
 */
PJ_DEF(pj_status_t) pj_stun_binary_attr_create(pj_pool_t *pool,
                                               int attr_type,
                                               const pj_uint8_t *data,
                                               unsigned length,
                                               pj_stun_binary_attr **p_attr)
{
    pj_stun_binary_attr *attr;

    PJ_ASSERT_RETURN(pool && attr_type && p_attr, PJ_EINVAL);
    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_binary_attr);
    *p_attr = attr;
    return pj_stun_binary_attr_init(attr, pool, attr_type, data, length);
}


/* Create and add binary attr. */
PJ_DEF(pj_status_t) pj_stun_msg_add_binary_attr(pj_pool_t *pool,
                                                pj_stun_msg *msg,
                                                int attr_type,
                                                const pj_uint8_t *data,
                                                unsigned length)
{
    pj_stun_binary_attr *attr = NULL;
    pj_status_t status;

    status = pj_stun_binary_attr_create(pool, attr_type,
                                        data, length, &attr);
    if (status != PJ_SUCCESS)
        return status;

    return pj_stun_msg_add_attr(msg, &attr->hdr);
}


static pj_status_t decode_binary_attr(pj_pool_t *pool, 
                                      const pj_uint8_t *buf,
                                      const pj_stun_msg_hdr *msghdr,
                                      void **p_attr)
{
    pj_stun_binary_attr *attr;

    PJ_UNUSED_ARG(msghdr);

    /* Create the attribute */
    attr = PJ_POOL_ZALLOC_T(pool, pj_stun_binary_attr);
    GETATTRHDR(buf, &attr->hdr);

    /* Copy the data to the attribute */
    attr->length = attr->hdr.length;
    attr->data = (pj_uint8_t*) pj_pool_alloc(pool, attr->length);
    pj_memcpy(attr->data, buf+ATTR_HDR_LEN, attr->length);

    /* Done */
    *p_attr = attr;

    return PJ_SUCCESS;

}


static pj_status_t encode_binary_attr(const void *a, pj_uint8_t *buf, 
                                      unsigned len, 
                                      const pj_stun_msg_hdr *msghdr,
                                      unsigned *printed)
{
    const pj_stun_binary_attr *ca = (const pj_stun_binary_attr*)a;

    PJ_CHECK_STACK();
    
    PJ_UNUSED_ARG(msghdr);

    /* Calculated total attr_len (add padding if necessary) */
    *printed = (ca->length + ATTR_HDR_LEN + 3) & (~3);
    if (len < *printed)
        return PJ_ETOOSMALL;

    PUTVAL16H(buf, 0, ca->hdr.type);
    PUTVAL16H(buf, 2, (pj_uint16_t) ca->length);

    /* Copy the data */
    pj_memcpy(buf+ATTR_HDR_LEN, ca->data, ca->length);

    /* Done */
    return PJ_SUCCESS;
}


static void* clone_binary_attr(pj_pool_t *pool, const void *src)
{
    const pj_stun_binary_attr *asrc = (const pj_stun_binary_attr*)src;
    pj_stun_binary_attr *dst = PJ_POOL_ALLOC_T(pool, pj_stun_binary_attr);

    pj_memcpy(dst, src, sizeof(pj_stun_binary_attr));

    if (asrc->length) {
        dst->data = (pj_uint8_t*) pj_pool_alloc(pool, asrc->length);
        pj_memcpy(dst->data, asrc->data, asrc->length);
    }

    return (void*)dst;
}

//////////////////////////////////////////////////////////////////////////////

/*
 * Initialize a generic STUN message.
 */
PJ_DEF(pj_status_t) pj_stun_msg_init( pj_stun_msg *msg,
                                      unsigned msg_type,
                                      pj_uint32_t magic,
                                      const pj_uint8_t tsx_id[12])
{
    PJ_ASSERT_RETURN(msg && msg_type, PJ_EINVAL);

    msg->hdr.type = (pj_uint16_t) msg_type;
    msg->hdr.length = 0;
    msg->hdr.magic = magic;
    msg->attr_count = 0;

    if (tsx_id) {
        pj_memcpy(&msg->hdr.tsx_id, tsx_id, sizeof(msg->hdr.tsx_id));
    } else {
        struct transaction_id
        {
            pj_uint32_t     proc_id;
            pj_uint32_t     random;
            pj_uint32_t     counter;
        } id;
        static pj_uint32_t pj_stun_tsx_id_counter;

        if (!pj_stun_tsx_id_counter)
            pj_stun_tsx_id_counter = pj_rand();

        id.proc_id = pj_getpid();
        id.random = pj_rand();
        id.counter = pj_stun_tsx_id_counter++;

        pj_memcpy(&msg->hdr.tsx_id, &id, sizeof(msg->hdr.tsx_id));
    }

    return PJ_SUCCESS;
}


/*
 * Create a blank STUN message.
 */
PJ_DEF(pj_status_t) pj_stun_msg_create( pj_pool_t *pool,
                                        unsigned msg_type,
                                        pj_uint32_t magic,
                                        const pj_uint8_t tsx_id[12],
                                        pj_stun_msg **p_msg)
{
    pj_stun_msg *msg;

    PJ_ASSERT_RETURN(pool && msg_type && p_msg, PJ_EINVAL);

    msg = PJ_POOL_ZALLOC_T(pool, pj_stun_msg);
    *p_msg = msg;
    return pj_stun_msg_init(msg, msg_type, magic, tsx_id);
}


/*
 * Clone a STUN message with all of its attributes.
 */
PJ_DEF(pj_stun_msg*) pj_stun_msg_clone( pj_pool_t *pool,
                                        const pj_stun_msg *src)
{
    pj_stun_msg *dst;
    unsigned i;

    PJ_ASSERT_RETURN(pool && src, NULL);

    dst = PJ_POOL_ZALLOC_T(pool, pj_stun_msg);
    pj_memcpy(dst, src, sizeof(pj_stun_msg));

    /* Duplicate the attributes */
    for (i=0, dst->attr_count=0; i<src->attr_count; ++i) {
        dst->attr[dst->attr_count] = pj_stun_attr_clone(pool, src->attr[i]);
        if (dst->attr[dst->attr_count])
            ++dst->attr_count;
    }

    return dst;
}


/*
 * Add STUN attribute to STUN message.
 */
PJ_DEF(pj_status_t) pj_stun_msg_add_attr(pj_stun_msg *msg,
                                         pj_stun_attr_hdr *attr)
{
    PJ_ASSERT_RETURN(msg && attr, PJ_EINVAL);
    PJ_ASSERT_RETURN(msg->attr_count < PJ_STUN_MAX_ATTR, PJ_ETOOMANY);

    msg->attr[msg->attr_count++] = attr;
    return PJ_SUCCESS;
}


/*
 * Check that the PDU is potentially a valid STUN message.
 */
PJ_DEF(pj_status_t) pj_stun_msg_check(const pj_uint8_t *pdu, pj_size_t pdu_len,
                                      unsigned options)
{
    pj_uint32_t msg_len;

    PJ_ASSERT_RETURN(pdu, PJ_EINVAL);

    if (pdu_len < sizeof(pj_stun_msg_hdr))
        return PJNATH_EINSTUNMSGLEN;

    /* First byte of STUN message is always 0x00 or 0x01. */
    if (*pdu != 0x00 && *pdu != 0x01)
        return PJNATH_EINSTUNMSGTYPE;

    /* Check the PDU length */
    msg_len = GETVAL16H(pdu, 2);
    if ((msg_len + 20 > pdu_len) || 
        ((options & PJ_STUN_IS_DATAGRAM) && msg_len + 20 != pdu_len))
    {
        return PJNATH_EINSTUNMSGLEN;
    }

    /* STUN message is always padded to the nearest 4 bytes, thus
     * the last two bits of the length field are always zero.
     */
    if ((msg_len & 0x03) != 0) {
        return PJNATH_EINSTUNMSGLEN;
    }

    /* If magic is set, then there is great possibility that this is
     * a STUN message.
     */
    if (GETVAL32H(pdu, 4) == PJ_STUN_MAGIC) {

        /* Check if FINGERPRINT attribute is present */
        if ((options & PJ_STUN_NO_FINGERPRINT_CHECK )==0 && 
            GETVAL16H(pdu, msg_len + 20 - 8) == PJ_STUN_ATTR_FINGERPRINT) 
        {
            pj_uint16_t attr_len = GETVAL16H(pdu, msg_len + 20 - 8 + 2);
            pj_uint32_t fingerprint = GETVAL32H(pdu, msg_len + 20 - 8 + 4);
            pj_uint32_t crc;

            if (attr_len != 4)
                return PJNATH_ESTUNINATTRLEN;

            crc = pj_crc32_calc(pdu, msg_len + 20 - 8);
            crc ^= STUN_XOR_FINGERPRINT;

            if (crc != fingerprint)
                return PJNATH_ESTUNFINGERPRINT;
        }
    }

    /* Could be a STUN message */
    return PJ_SUCCESS;
}


/* Create error response */
PJ_DEF(pj_status_t) pj_stun_msg_create_response(pj_pool_t *pool,
                                                const pj_stun_msg *req_msg,
                                                unsigned err_code,
                                                const pj_str_t *err_msg,
                                                pj_stun_msg **p_response)
{
    unsigned msg_type = req_msg->hdr.type;
    pj_stun_msg *response = NULL;
    pj_status_t status;

    PJ_ASSERT_RETURN(pool && p_response, PJ_EINVAL);

    PJ_ASSERT_RETURN(PJ_STUN_IS_REQUEST(msg_type), 
                     PJNATH_EINSTUNMSGTYPE);

    /* Create response or error response */
    if (err_code)
        msg_type |= PJ_STUN_ERROR_RESPONSE_BIT;
    else
        msg_type |= PJ_STUN_SUCCESS_RESPONSE_BIT;

    status = pj_stun_msg_create(pool, msg_type, req_msg->hdr.magic, 
                                req_msg->hdr.tsx_id, &response);
    if (status != PJ_SUCCESS) {
        return status;
    }

    /* Add error code attribute */
    if (err_code) {
        status = pj_stun_msg_add_errcode_attr(pool, response, 
                                              err_code, err_msg);
        if (status != PJ_SUCCESS) {
            return status;
        }
    }

    *p_response = response;
    return PJ_SUCCESS;
}


/*
 * Parse incoming packet into STUN message.
 */
PJ_DEF(pj_status_t) pj_stun_msg_decode(pj_pool_t *pool,
                                       const pj_uint8_t *pdu,
                                       pj_size_t pdu_len,
                                       unsigned options,
                                       pj_stun_msg **p_msg,
                                       pj_size_t *p_parsed_len,
                                       pj_stun_msg **p_response)
{
    
    pj_stun_msg *msg;
    const pj_uint8_t *start_pdu = pdu;
    pj_bool_t has_msg_int = PJ_FALSE;
    pj_bool_t has_fingerprint = PJ_FALSE;
    pj_status_t status;

    PJ_UNUSED_ARG(options);

    PJ_ASSERT_RETURN(pool && pdu && pdu_len && p_msg, PJ_EINVAL);
    PJ_ASSERT_RETURN(sizeof(pj_stun_msg_hdr) == 20, PJ_EBUG);

    if (p_parsed_len)
        *p_parsed_len = 0;
    if (p_response)
        *p_response = NULL;

    /* Check if this is a STUN message, if necessary */
    if (options & PJ_STUN_CHECK_PACKET) {
        status = pj_stun_msg_check(pdu, pdu_len, options);
        if (status != PJ_SUCCESS)
            return status;
    } else {
        /* For safety, verify packet length at least */
        pj_uint32_t msg_len = GETVAL16H(pdu, 2) + 20;
        if (msg_len > pdu_len ||
            ((options & PJ_STUN_IS_DATAGRAM) && msg_len != pdu_len))
        {
            return PJNATH_EINSTUNMSGLEN;
        }
    }

    /* Create the message, copy the header, and convert to host byte order */
    msg = PJ_POOL_ZALLOC_T(pool, pj_stun_msg);
    pj_memcpy(&msg->hdr, pdu, sizeof(pj_stun_msg_hdr));
    msg->hdr.type = pj_ntohs(msg->hdr.type);
    msg->hdr.length = pj_ntohs(msg->hdr.length);
    msg->hdr.magic = pj_ntohl(msg->hdr.magic);

    pdu += sizeof(pj_stun_msg_hdr);
    /* pdu_len -= sizeof(pj_stun_msg_hdr); */
    pdu_len = msg->hdr.length;

    /* No need to create response if this is not a request */
    if (!PJ_STUN_IS_REQUEST(msg->hdr.type))
        p_response = NULL;

    /* Parse attributes */
    while (pdu_len >= ATTR_HDR_LEN) {
        unsigned attr_type, attr_val_len;
        const struct attr_desc *adesc;

        /* Get attribute type and length. If length is not aligned
         * to 4 bytes boundary, add padding.
         */
        attr_type = GETVAL16H(pdu, 0);
        attr_val_len = GETVAL16H(pdu, 2);
        attr_val_len = (attr_val_len + 3) & (~3);

        /* Check length */
        if (pdu_len < attr_val_len + ATTR_HDR_LEN) {
            pj_str_t err_msg;
            char err_msg_buf[80];

            err_msg.ptr = err_msg_buf;
            err_msg.slen = pj_ansi_snprintf(err_msg_buf, sizeof(err_msg_buf),
                                            "Attribute %s has invalid length",
                                            pj_stun_get_attr_name(attr_type));

            PJ_LOG(4,(THIS_FILE, "Error decoding message: %.*s",
                      (int)err_msg.slen, err_msg.ptr));

            if (p_response) {
                pj_stun_msg_create_response(pool, msg, 
                                            PJ_STUN_SC_BAD_REQUEST, 
                                            &err_msg, p_response);
            }
            return PJNATH_ESTUNINATTRLEN;
        }

        /* Get the attribute descriptor */
        adesc = find_attr_desc(attr_type);

        if (adesc == NULL) {
            /* Unrecognized attribute */
            pj_stun_binary_attr *attr = NULL;

            PJ_LOG(5,(THIS_FILE, "Unrecognized attribute type 0x%x", 
                      attr_type));

            /* Is this a fatal condition? */
            if (attr_type <= 0x7FFF) {
                /* This is a mandatory attribute, we must return error
                 * if we don't understand the attribute.
                 */
                if (p_response) {
                    unsigned err_code = PJ_STUN_SC_UNKNOWN_ATTRIBUTE;

                    status = pj_stun_msg_create_response(pool, msg,
                                                         err_code, NULL, 
                                                         p_response);
                    if (status==PJ_SUCCESS) {
                        pj_uint16_t d = (pj_uint16_t)attr_type;
                        pj_stun_msg_add_unknown_attr(pool, *p_response, 1, &d);
                    }
                }

                return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_UNKNOWN_ATTRIBUTE);
            }

            /* Make sure we have rooms for the new attribute */
            if (msg->attr_count >= PJ_STUN_MAX_ATTR) {
                if (p_response) {
                    pj_stun_msg_create_response(pool, msg,
                                                PJ_STUN_SC_SERVER_ERROR,
                                                NULL, p_response);
                }
                return PJNATH_ESTUNTOOMANYATTR;
            }

            /* Create binary attribute to represent this */
            status = pj_stun_binary_attr_create(pool, attr_type, pdu+4, 
                                                GETVAL16H(pdu, 2), &attr);
            if (status != PJ_SUCCESS) {
                if (p_response) {
                    pj_stun_msg_create_response(pool, msg,
                                                PJ_STUN_SC_SERVER_ERROR,
                                                NULL, p_response);
                }

                PJ_LOG(4,(THIS_FILE, 
                          "Error parsing unknown STUN attribute type %d",
                          attr_type));

                return status;
            }

            /* Add the attribute */
            msg->attr[msg->attr_count++] = &attr->hdr;

        } else {
            void *attr;
            char err_msg1[PJ_ERR_MSG_SIZE],
                 err_msg2[PJ_ERR_MSG_SIZE];

            /* Parse the attribute */
            status = (adesc->decode_attr)(pool, pdu, &msg->hdr, &attr);

            if (status != PJ_SUCCESS) {
                pj_strerror(status, err_msg1, sizeof(err_msg1));

                if (p_response) {
                    pj_str_t e;

                    e.ptr = err_msg2;
                    e.slen= pj_ansi_snprintf(err_msg2, sizeof(err_msg2),
                                             "%s in %s",
                                             err_msg1,
                                             pj_stun_get_attr_name(attr_type));
                    if (e.slen < 1 || e.slen >= (int)sizeof(err_msg2))
                        e.slen = sizeof(err_msg2) - 1;
                    pj_stun_msg_create_response(pool, msg,
                                                PJ_STUN_SC_BAD_REQUEST,
                                                &e, p_response);
                }

                PJ_LOG(4,(THIS_FILE, 
                          "Error parsing STUN attribute %s: %s",
                          pj_stun_get_attr_name(attr_type), 
                          err_msg1));

                return status;
            }

            if (attr_type == PJ_STUN_ATTR_MESSAGE_INTEGRITY && 
                !has_fingerprint) 
            {
                if (has_msg_int) {
                    /* Already has MESSAGE-INTEGRITY */
                    if (p_response) {
                        pj_stun_msg_create_response(pool, msg,
                                                    PJ_STUN_SC_BAD_REQUEST,
                                                    NULL, p_response);
                    }
                    return PJNATH_ESTUNDUPATTR;
                }
                has_msg_int = PJ_TRUE;

            } else if (attr_type == PJ_STUN_ATTR_FINGERPRINT) {
                if (has_fingerprint) {
                    /* Already has FINGERPRINT */
                    if (p_response) {
                        pj_stun_msg_create_response(pool, msg,
                                                    PJ_STUN_SC_BAD_REQUEST,
                                                    NULL, p_response);
                    }
                    return PJNATH_ESTUNDUPATTR;
                }
                has_fingerprint = PJ_TRUE;
            } else {
                if (has_fingerprint) {
                    /* Another attribute is found which is not FINGERPRINT
                     * after FINGERPRINT. Note that non-FINGERPRINT is
                     * allowed to appear after M-I
                     */
                    if (p_response) {
                        pj_stun_msg_create_response(pool, msg,
                                                    PJ_STUN_SC_BAD_REQUEST,
                                                    NULL, p_response);
                    }
                    return PJNATH_ESTUNFINGERPOS;
                }
            }

            /* Make sure we have rooms for the new attribute */
            if (msg->attr_count >= PJ_STUN_MAX_ATTR) {
                if (p_response) {
                    pj_stun_msg_create_response(pool, msg,
                                                PJ_STUN_SC_SERVER_ERROR,
                                                NULL, p_response);
                }
                return PJNATH_ESTUNTOOMANYATTR;
            }

            /* Add the attribute */
            msg->attr[msg->attr_count++] = (pj_stun_attr_hdr*)attr;
        }

        /* Next attribute */
        if (attr_val_len + 4 >= pdu_len) {
            pdu += pdu_len;
            pdu_len = 0;
        } else {
            pdu += (attr_val_len + 4);
            pdu_len -= (attr_val_len + 4);
        }
    }

    if (pdu_len > 0) {
        /* Stray trailing bytes */
        PJ_LOG(4,(THIS_FILE, 
                  "Error decoding STUN message: unparsed trailing %ld bytes",
                  pdu_len));
        return PJNATH_EINSTUNMSGLEN;
    }

    *p_msg = msg;

    if (p_parsed_len)
        *p_parsed_len = (pdu - start_pdu);

    return PJ_SUCCESS;
}

/*
static char *print_binary(const pj_uint8_t *data, unsigned data_len)
{
    static char static_buffer[1024];
    char *buffer = static_buffer, end=static_buffer+sizeof(static_buffer);
    unsigned length=sizeof(static_buffer), i;

    if (length < data_len * 2 + 8)
        return "";

    pj_ansi_snprintf(buffer, end-buffer, ", data=");
    buffer += 7;

    for (i=0; i<data_len; ++i) {
        pj_ansi_snprintf(buffer, end-buffer, "%02x", (*data) & 0xFF);
        buffer += 2;
        data++;
    }

    pj_ansi_snprintf(buffer, end-buffer, "\n");
    buffer++;

    return static_buffer;
}
*/

/*
 * Print the message structure to a buffer.
 */
PJ_DEF(pj_status_t) pj_stun_msg_encode(pj_stun_msg *msg,
                                       pj_uint8_t *buf, pj_size_t buf_size,
                                       unsigned options,
                                       const pj_str_t *key,
                                       pj_size_t *p_msg_len)
{
    pj_uint8_t *start = buf;
    pj_stun_msgint_attr *amsgint = NULL;
    pj_stun_fingerprint_attr *afingerprint = NULL;
    unsigned printed = 0, body_len;
    pj_status_t status;
    unsigned i;


    PJ_ASSERT_RETURN(msg && buf && buf_size, PJ_EINVAL);

    PJ_UNUSED_ARG(options);
    PJ_ASSERT_RETURN(options == 0, PJ_EINVAL);

    /* Copy the message header part and convert the header fields to
     * network byte order
     */
    if (buf_size < sizeof(pj_stun_msg_hdr))
        return PJ_ETOOSMALL;
    
    PUTVAL16H(buf, 0, msg->hdr.type);
    PUTVAL16H(buf, 2, 0);   /* length will be calculated later */
    PUTVAL32H(buf, 4, msg->hdr.magic);
    pj_memcpy(buf+8, msg->hdr.tsx_id, sizeof(msg->hdr.tsx_id));

    buf += sizeof(pj_stun_msg_hdr);
    buf_size -= sizeof(pj_stun_msg_hdr);

    /* Encode each attribute to the message */
    for (i=0; i<msg->attr_count; ++i) {
        const struct attr_desc *adesc;
        const pj_stun_attr_hdr *attr_hdr = msg->attr[i];

        if (attr_hdr->type == PJ_STUN_ATTR_MESSAGE_INTEGRITY) {
            pj_assert(amsgint == NULL);
            amsgint = (pj_stun_msgint_attr*) attr_hdr;

            /* Stop when encountering MESSAGE-INTEGRITY */
            break;

        } else if (attr_hdr->type == PJ_STUN_ATTR_FINGERPRINT) {
            afingerprint = (pj_stun_fingerprint_attr*) attr_hdr;
            break;
        }

        adesc = find_attr_desc(attr_hdr->type);
        if (adesc) {
            status = adesc->encode_attr(attr_hdr, buf, (unsigned)buf_size, 
                                        &msg->hdr, &printed);
        } else {
            /* This may be a generic attribute */
            const pj_stun_binary_attr *bin_attr = (const pj_stun_binary_attr*) 
                                                   attr_hdr;
            PJ_ASSERT_RETURN(bin_attr->magic == PJ_STUN_MAGIC, PJ_EBUG);
            status = encode_binary_attr(bin_attr, buf, (unsigned)buf_size, 
                                        &msg->hdr, &printed);
        }

        if (status != PJ_SUCCESS)
            return status;

        buf += printed;
        buf_size -= printed;
    }

    /* We may have stopped printing attribute because we found
     * MESSAGE-INTEGRITY or FINGERPRINT. Scan the rest of the
     * attributes.
     */
    for ( ++i; i<msg->attr_count; ++i) {
        const pj_stun_attr_hdr *attr_hdr = msg->attr[i];

        /* There mustn't any attribute after FINGERPRINT */
        PJ_ASSERT_RETURN(afingerprint == NULL, PJNATH_ESTUNFINGERPOS);

        if (attr_hdr->type == PJ_STUN_ATTR_MESSAGE_INTEGRITY) {
            /* There mustn't be MESSAGE-INTEGRITY before */
            PJ_ASSERT_RETURN(amsgint == NULL, 
                             PJNATH_ESTUNMSGINTPOS);
            amsgint = (pj_stun_msgint_attr*) attr_hdr;

        } else if (attr_hdr->type == PJ_STUN_ATTR_FINGERPRINT) {
            afingerprint = (pj_stun_fingerprint_attr*) attr_hdr;
        }
    }

#if PJ_STUN_OLD_STYLE_MI_FINGERPRINT
    /*
     * This is the old style MESSAGE-INTEGRITY and FINGERPRINT
     * calculation, used in rfc3489bis-06 and older.
     */
    /* We MUST update the message length in the header NOW before
     * calculating MESSAGE-INTEGRITY and FINGERPRINT. 
     * Note that length is not including the 20 bytes header.
      */
    if (amsgint && afingerprint) {
        body_len = (pj_uint16_t)((buf - start) - 20 + 24 + 8);
    } else if (amsgint) {
        body_len = (pj_uint16_t)((buf - start) - 20 + 24);
    } else if (afingerprint) {
        body_len = (pj_uint16_t)((buf - start) - 20 + 8);
    } else {
        body_len = (pj_uint16_t)((buf - start) - 20);
    }
#else
    /* If MESSAGE-INTEGRITY is present, include the M-I attribute
     * in message length before calculating M-I
     */
    if (amsgint) {
        body_len = (pj_uint16_t)((buf - start) - 20 + 24);
    } else {
        body_len = (pj_uint16_t)((buf - start) - 20);
    }
#endif  /* PJ_STUN_OLD_STYLE_MI_FINGERPRINT */

    /* hdr->length = pj_htons(length); */
    PUTVAL16H(start, 2, (pj_uint16_t)body_len);

    /* Calculate message integrity, if present */
    if (amsgint != NULL) {
        pj_hmac_sha1_context ctx;

        /* Key MUST be specified */
        PJ_ASSERT_RETURN(key, PJ_EINVALIDOP);

        /* MESSAGE-INTEGRITY must be the last attribute in the message, or
         * the last attribute before FINGERPRINT.
         */
        if (msg->attr_count>1 && i < msg->attr_count-2) {
            /* Should not happen for message generated by us */
            pj_assert(PJ_FALSE);
            return PJNATH_ESTUNMSGINTPOS;

        } else if (i == msg->attr_count-2)  {
            if (msg->attr[i+1]->type != PJ_STUN_ATTR_FINGERPRINT) {
                /* Should not happen for message generated by us */
                pj_assert(PJ_FALSE);
                return PJNATH_ESTUNMSGINTPOS;
            } else {
                afingerprint = (pj_stun_fingerprint_attr*) msg->attr[i+1];
            }
        }

        /* Calculate HMAC-SHA1 digest, add zero padding to input
         * if necessary to make the input 64 bytes aligned.
         */
        pj_hmac_sha1_init(&ctx, (const pj_uint8_t*)key->ptr, 
                          (unsigned)key->slen);
        pj_hmac_sha1_update(&ctx, (const pj_uint8_t*)start, 
                            (unsigned)(buf-start));
#if PJ_STUN_OLD_STYLE_MI_FINGERPRINT
        // These are obsoleted in rfc3489bis-08
        if ((buf-start) & 0x3F) {
            pj_uint8_t zeroes[64];
            pj_bzero(zeroes, sizeof(zeroes));
            pj_hmac_sha1_update(&ctx, zeroes, 64-((buf-start) & 0x3F));
        }
#endif  /* PJ_STUN_OLD_STYLE_MI_FINGERPRINT */
        pj_hmac_sha1_final(&ctx, amsgint->hmac);

        /* Put this attribute in the message */
        status = encode_msgint_attr(amsgint, buf, (unsigned)buf_size, 
                                    &msg->hdr, &printed);
        if (status != PJ_SUCCESS)
            return status;

        buf += printed;
        buf_size -= printed;
    }

    /* Calculate FINGERPRINT if present */
    if (afingerprint != NULL) {

#if !PJ_STUN_OLD_STYLE_MI_FINGERPRINT
        /* Update message length */
        PUTVAL16H(start, 2, 
                 (pj_uint16_t)(GETVAL16H(start, 2)+8));
#endif

        afingerprint->value = pj_crc32_calc(start, buf-start);
        afingerprint->value ^= STUN_XOR_FINGERPRINT;

        /* Put this attribute in the message */
        status = encode_uint_attr(afingerprint, buf, (unsigned)buf_size, 
                                  &msg->hdr, &printed);
        if (status != PJ_SUCCESS)
            return status;

        buf += printed;
        buf_size -= printed;
    }

    /* Update message length. */
    msg->hdr.length = (pj_uint16_t) ((buf - start) - 20);

    /* Return the length */
    if (p_msg_len)
        *p_msg_len = (buf - start);

    return PJ_SUCCESS;
}


/*
 * Find STUN attribute in the STUN message, starting from the specified
 * index.
 */
PJ_DEF(pj_stun_attr_hdr*) pj_stun_msg_find_attr( const pj_stun_msg *msg,
                                                 int attr_type,
                                                 unsigned index)
{
    PJ_ASSERT_RETURN(msg, NULL);

    for (; index < msg->attr_count; ++index) {
        if (msg->attr[index]->type == attr_type)
            return (pj_stun_attr_hdr*) msg->attr[index];
    }

    return NULL;
}


/*
 * Clone a STUN attribute.
 */
PJ_DEF(pj_stun_attr_hdr*) pj_stun_attr_clone( pj_pool_t *pool,
                                              const pj_stun_attr_hdr *attr)
{
    const struct attr_desc *adesc;

    /* Get the attribute descriptor */
    adesc = find_attr_desc(attr->type);
    if (adesc) {
        return (pj_stun_attr_hdr*) (*adesc->clone_attr)(pool, attr);
    } else {
        /* Clone generic attribute */
        const pj_stun_binary_attr *bin_attr = (const pj_stun_binary_attr*)
                                               attr;
        PJ_ASSERT_RETURN(bin_attr->magic == PJ_STUN_MAGIC, NULL);
        if (bin_attr->magic == PJ_STUN_MAGIC) {
            return (pj_stun_attr_hdr*) clone_binary_attr(pool, attr);
        } else {
            return NULL;
        }
    }
}


