/src/coturn/src/client/ns_turn_msg.c

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/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * https://opensource.org/license/bsd-3-clause
 *
 * Copyright (C) 2011, 2012, 2013 Citrix Systems
 *
 * 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. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS 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 PROJECT OR 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.
 */

#include "ns_turn_msg.h"
#include "ns_turn_msg_addr.h"

///////////// Security functions implementation from ns_turn_msg.h ///////////

#include "ns_turn_openssl.h"
#include "ns_turn_utils.h"

///////////

#include <ctype.h> // for tolower
#include <stdbool.h>
#include <stdio.h> // for fprintf, printf, stderr, snprintf
#include <stdlib.h>
#include <string.h> // for memcpy, strlen, memset, strncpy, strcmp

///////////

#define FINGERPRINT_XOR 0x5354554e

///////////

int stun_method_str(uint16_t method, char *smethod) {
  int ret = 0;

  const char *s = "UNKNOWN";

  switch (method) {
  case STUN_METHOD_BINDING:
    s = "BINDING";
    break;
  case STUN_METHOD_ALLOCATE:
    s = "ALLOCATE";
    break;
  case STUN_METHOD_REFRESH:
    s = "REFRESH";
    break;
  case STUN_METHOD_SEND:
    s = "SEND";
    break;
  case STUN_METHOD_DATA:
    s = "DATA";
    break;
  case STUN_METHOD_CREATE_PERMISSION:
    s = "CREATE_PERMISSION";
    break;
  case STUN_METHOD_CHANNEL_BIND:
    s = "CHANNEL_BIND";
    break;
  case STUN_METHOD_CONNECT:
    s = "CONNECT";
    break;
  case STUN_METHOD_CONNECTION_BIND:
    s = "CONNECTION_BIND";
    break;
  case STUN_METHOD_CONNECTION_ATTEMPT:
    s = "CONNECTION_ATTEMPT";
    break;
  default:
    ret = -1;
  };

  if (smethod) {
    strcpy(smethod, s);
  }

  return ret;
}

long turn_random_number(void) {
  long ret = 0;
  if (!RAND_bytes((unsigned char *)&ret, sizeof(ret)))
#if defined(WINDOWS)
    ret = rand();
#else
    ret = random();
#endif
  return ret;
}

static void generate_random_nonce(unsigned char *nonce, size_t sz) {
  if (!RAND_bytes(nonce, (int)sz)) {
    for (size_t i = 0; i < sz; ++i) {
      nonce[i] = (unsigned char)turn_random_number();
    }
  }
}

static void turn_random_tid_size(void *id) {
  uint32_t *ar = (uint32_t *)id;
  if (!RAND_bytes((unsigned char *)ar, 12)) {
    for (size_t i = 0; i < 3; ++i) {
      ar[i] = (uint32_t)turn_random_number();
    }
  }
}

bool stun_calculate_hmac(const uint8_t *buf, size_t len, const uint8_t *key, size_t keylen, uint8_t *hmac,
                         unsigned int *hmac_len, SHATYPE shatype) {
  ERR_clear_error();
  UNUSED_ARG(shatype);

  if (shatype == SHATYPE_SHA256) {
#if !defined(OPENSSL_NO_SHA256) && defined(SHA256_DIGEST_LENGTH)
    if (!HMAC(EVP_sha256(), key, (int)keylen, buf, len, hmac, hmac_len)) {
      return false;
    }
#else
    fprintf(stderr, "SHA256 is not supported\n");
    return false;
#endif
  } else if (shatype == SHATYPE_SHA384) {
#if !defined(OPENSSL_NO_SHA384) && defined(SHA384_DIGEST_LENGTH)
    if (!HMAC(EVP_sha384(), key, (int)keylen, buf, len, hmac, hmac_len)) {
      return false;
    }
#else
    fprintf(stderr, "SHA384 is not supported\n");
    return false;
#endif
  } else if (shatype == SHATYPE_SHA512) {
#if !defined(OPENSSL_NO_SHA512) && defined(SHA512_DIGEST_LENGTH)
    if (!HMAC(EVP_sha512(), key, (int)keylen, buf, len, hmac, hmac_len)) {
      return false;
    }
#else
    fprintf(stderr, "SHA512 is not supported\n");
    return false;
#endif
  } else if (!HMAC(EVP_sha1(), key, (int)keylen, buf, len, hmac, hmac_len)) {
    return false;
  }

  return true;
}

bool stun_produce_integrity_key_str(const uint8_t *uname, const uint8_t *realm, const uint8_t *upwd, hmackey_t key,
                                    SHATYPE shatype) {
  bool ret;

  ERR_clear_error();
  UNUSED_ARG(shatype);

  size_t ulen = strlen((const char *)uname);
  size_t rlen = strlen((const char *)realm);
  size_t plen = strlen((const char *)upwd);
  size_t sz = ulen + 1 + rlen + 1 + plen + 1 + 10;
  size_t strl = ulen + 1 + rlen + 1 + plen;
  uint8_t *str = (uint8_t *)malloc(sz + 1);

  strncpy((char *)str, (const char *)uname, sz);
  str[ulen] = ':';
  strncpy((char *)str + ulen + 1, (const char *)realm, sz - ulen - 1);
  str[ulen + 1 + rlen] = ':';
  strncpy((char *)str + ulen + 1 + rlen + 1, (const char *)upwd, sz - ulen - 1 - rlen - 1);
  str[strl] = 0;

  if (shatype == SHATYPE_SHA256) {
#if !defined(OPENSSL_NO_SHA256) && defined(SHA256_DIGEST_LENGTH)
    unsigned int keylen = 0;
    EVP_MD_CTX *ctx = EVP_MD_CTX_new();
    EVP_DigestInit(ctx, EVP_sha256());
    EVP_DigestUpdate(ctx, str, strl);
    EVP_DigestFinal(ctx, key, &keylen);
    EVP_MD_CTX_free(ctx);
    ret = true;
#else
    fprintf(stderr, "SHA256 is not supported\n");
    ret = false;
#endif
  } else if (shatype == SHATYPE_SHA384) {
#if !defined(OPENSSL_NO_SHA384) && defined(SHA384_DIGEST_LENGTH)
    unsigned int keylen = 0;
    EVP_MD_CTX *ctx = EVP_MD_CTX_new();
    EVP_DigestInit(ctx, EVP_sha384());
    EVP_DigestUpdate(ctx, str, strl);
    EVP_DigestFinal(ctx, key, &keylen);
    EVP_MD_CTX_free(ctx);
    ret = true;
#else
    fprintf(stderr, "SHA384 is not supported\n");
    ret = false;
#endif
  } else if (shatype == SHATYPE_SHA512) {
#if !defined(OPENSSL_NO_SHA512) && defined(SHA512_DIGEST_LENGTH)
    unsigned int keylen = 0;
    EVP_MD_CTX *ctx = EVP_MD_CTX_new();
    EVP_DigestInit(ctx, EVP_sha512());
    EVP_DigestUpdate(ctx, str, strl);
    EVP_DigestFinal(ctx, key, &keylen);
    EVP_MD_CTX_free(ctx);
    ret = true;
#else
    fprintf(stderr, "SHA512 is not supported\n");
    ret = false;
#endif
  } else {
#if OPENSSL_VERSION_NUMBER >= 0x30000000L
    unsigned int keylen = 0;
    EVP_MD_CTX *ctx = EVP_MD_CTX_new();
    if (EVP_default_properties_is_fips_enabled(NULL)) {
      EVP_default_properties_enable_fips(NULL, 0);
    }
    EVP_DigestInit_ex(ctx, EVP_md5(), NULL);
    EVP_DigestUpdate(ctx, str, strl);
    EVP_DigestFinal(ctx, key, &keylen);
    EVP_MD_CTX_free(ctx);
#else // OPENSSL_VERSION_NUMBER < 0x30000000L
    unsigned int keylen = 0;
    EVP_MD_CTX *ctx = EVP_MD_CTX_new();
#if defined EVP_MD_CTX_FLAG_NON_FIPS_ALLOW && !defined(LIBRESSL_VERSION_NUMBER)
    if (FIPS_mode()) {
      EVP_MD_CTX_set_flags(ctx, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
    }
#endif
    EVP_DigestInit_ex(ctx, EVP_md5(), NULL);
    EVP_DigestUpdate(ctx, str, strl);
    EVP_DigestFinal(ctx, key, &keylen);
    EVP_MD_CTX_free(ctx);
#endif // OPENSSL_VERSION_NUMBER >= 0X30000000L
    ret = true;
  }

  free(str);

  return ret;
}

#define PWD_SALT_SIZE (8)

static void readable_string(unsigned char *orig, unsigned char *out, size_t sz) {
  out[0] = '\0';
  for (size_t i = 0; i < sz; ++i) {
    snprintf((char *)(out + (i * 2)), 3, "%02x", (unsigned int)orig[i]);
  }
  out[sz * 2] = 0;
}

static void generate_enc_password(const char *pwd, char *result, const unsigned char *orig_salt) {
  unsigned char salt[PWD_SALT_SIZE + 1];
  if (!orig_salt) {
    generate_random_nonce(salt, PWD_SALT_SIZE);
  } else {
    memcpy(salt, orig_salt, PWD_SALT_SIZE);
    salt[PWD_SALT_SIZE] = 0;
  }
  unsigned char rsalt[PWD_SALT_SIZE * 2 + 1];
  readable_string(salt, rsalt, PWD_SALT_SIZE);
  result[0] = '$';
  result[1] = '5';
  result[2] = '$';
  memcpy(result + 3, (char *)rsalt, PWD_SALT_SIZE + PWD_SALT_SIZE);
  result[3 + PWD_SALT_SIZE + PWD_SALT_SIZE] = '$';
  unsigned char *out = (unsigned char *)(result + 3 + PWD_SALT_SIZE + PWD_SALT_SIZE + 1);
  {
    EVP_MD_CTX *ctx = EVP_MD_CTX_new();
#if !defined(OPENSSL_NO_SHA256) && defined(SHA256_DIGEST_LENGTH)
    EVP_DigestInit(ctx, EVP_sha256());
#else
    EVP_DigestInit(ctx, EVP_sha1());
#endif
    EVP_DigestUpdate(ctx, salt, PWD_SALT_SIZE);
    EVP_DigestUpdate(ctx, pwd, strlen(pwd));
    {
      unsigned char hash[129];
      unsigned int keylen = 0;
      EVP_DigestFinal(ctx, hash, &keylen);
      readable_string(hash, out, keylen);
    }
    EVP_MD_CTX_free(ctx);
  }
}

void generate_new_enc_password(const char *pwd, char *result) { generate_enc_password(pwd, result, NULL); }

static bool encrypted_password(const char *pin, unsigned char *salt) {
  static const size_t min_len = 3 + PWD_SALT_SIZE + PWD_SALT_SIZE + 1 + 32;
  if (strlen(pin) >= min_len) {
    if ((pin[0] == '$') && (pin[1] == '5') && (pin[2] == '$') && (pin[3 + PWD_SALT_SIZE + PWD_SALT_SIZE] == '$')) {
      for (size_t i = 0; i < PWD_SALT_SIZE; ++i) {
        const char *c = pin + 3 + i + i;
        char sc[3];
        sc[0] = c[0];
        sc[1] = c[1];
        sc[2] = 0;
        salt[i] = (unsigned char)strtoul(sc, NULL, 16);
      }
      return true;
    }
  }
  return false;
}

bool check_password_equal(const char *pin, const char *pwd) {
  unsigned char salt[PWD_SALT_SIZE];
  if (!encrypted_password(pwd, salt)) {
    return 0 == strcmp(pin, pwd);
  }
  char enc_pin[257];
  generate_enc_password(pin, enc_pin, salt);
  return 0 == strcmp(enc_pin, pwd);
}

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

static uint32_t ns_crc32(const uint8_t *buffer, uint32_t len);

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

int stun_get_command_message_len_str(const uint8_t *buf, size_t len) {
  if (len < STUN_HEADER_LENGTH) {
    return -1;
  }

  /* Validate the size the buffer claims to be */
  size_t bufLen = (size_t)(nswap16(((const uint16_t *)(buf))[1]) + STUN_HEADER_LENGTH);
  if (bufLen > len) {
    return -1;
  }

  return bufLen;
}

static bool stun_set_command_message_len_str(uint8_t *buf, int len) {
  if (len < STUN_HEADER_LENGTH) {
    return false;
  }
  ((uint16_t *)buf)[1] = nswap16((uint16_t)(len - STUN_HEADER_LENGTH));
  return true;
}

///////////  Low-level binary //////////////////////////////////////////////

uint16_t stun_make_type(uint16_t method) {
  method = method & 0x0FFF;
  return ((method & 0x000F) | ((method & 0x0070) << 1) | ((method & 0x0380) << 2) | ((method & 0x0C00) << 2));
}

uint16_t stun_get_method_str(const uint8_t *buf, size_t len) {
  if (!buf || len < 2) {
    return (uint16_t)-1;
  }

  uint16_t tt = nswap16(((const uint16_t *)buf)[0]);

  return (tt & 0x000F) | ((tt & 0x00E0) >> 1) | ((tt & 0x0E00) >> 2) | ((tt & 0x3000) >> 2);
}

uint16_t stun_get_msg_type_str(const uint8_t *buf, size_t len) {
  if (!buf || len < 2) {
    return (uint16_t)-1;
  }
  return ((nswap16(((const uint16_t *)buf)[0])) & 0x3FFF);
}

bool is_channel_msg_str(const uint8_t *buf, size_t blen) {
  return (buf && blen >= 4 && STUN_VALID_CHANNEL(nswap16(((const uint16_t *)buf)[0])));
}

/////////////// message types /////////////////////////////////

bool stun_is_command_message_str(const uint8_t *buf, size_t blen) {
  if (buf && blen >= STUN_HEADER_LENGTH) {
    if (!STUN_VALID_CHANNEL(nswap16(((const uint16_t *)buf)[0]))) {
      if ((((uint8_t)buf[0]) & ((uint8_t)(0xC0))) == 0) {
        if (nswap32(((const uint32_t *)(buf))[1]) == STUN_MAGIC_COOKIE) {
          uint16_t len = nswap16(((const uint16_t *)(buf))[1]);
          if ((len & 0x0003) == 0) {
            if ((size_t)(len + STUN_HEADER_LENGTH) == blen) {
              return true;
            }
          }
        }
      }
    }
  }
  return false;
}

bool old_stun_is_command_message_str(const uint8_t *buf, size_t blen, uint32_t *cookie) {
  if (buf && blen >= STUN_HEADER_LENGTH) {
    if (!STUN_VALID_CHANNEL(nswap16(((const uint16_t *)buf)[0]))) {
      if ((((uint8_t)buf[0]) & ((uint8_t)(0xC0))) == 0) {
        if (nswap32(((const uint32_t *)(buf))[1]) != STUN_MAGIC_COOKIE) {
          uint16_t len = nswap16(((const uint16_t *)(buf))[1]);
          if ((len & 0x0003) == 0) {
            if ((size_t)(len + STUN_HEADER_LENGTH) == blen) {
              *cookie = nswap32(((const uint32_t *)(buf))[1]);
              return true;
            }
          }
        }
      }
    }
  }
  return false;
}

bool stun_is_command_message_full_check_str(const uint8_t *buf, size_t blen, int must_check_fingerprint,
                                            int *fingerprint_present) {
  if (!stun_is_command_message_str(buf, blen)) {
    return false;
  }
  stun_attr_ref sar = stun_attr_get_first_by_type_str(buf, blen, STUN_ATTRIBUTE_FINGERPRINT);
  if (!sar) {
    if (fingerprint_present) {
      *fingerprint_present = 0;
    }
    if (stun_get_method_str(buf, blen) == STUN_METHOD_BINDING) {
      return true;
    }
    return !must_check_fingerprint;
  }
  if (stun_attr_get_len(sar) != 4) {
    return false;
  }
  const uint32_t *fingerprint = (const uint32_t *)stun_attr_get_value(sar);
  if (!fingerprint) {
    return !must_check_fingerprint;
  }
  uint32_t crc32len = (uint32_t)((((const uint8_t *)fingerprint) - buf) - 4);
  bool ret = (*fingerprint == nswap32(ns_crc32(buf, crc32len) ^ ((uint32_t)FINGERPRINT_XOR)));
  if (ret && fingerprint_present) {
    *fingerprint_present = ret;
  }
  return ret;
}

bool stun_is_request_str(const uint8_t *buf, size_t len) {
  if (is_channel_msg_str(buf, len)) {
    return false;
  }
  return IS_STUN_REQUEST(stun_get_msg_type_str(buf, len));
}

bool stun_is_success_response_str(const uint8_t *buf, size_t len) {
  if (is_channel_msg_str(buf, len)) {
    return false;
  }
  return IS_STUN_SUCCESS_RESP(stun_get_msg_type_str(buf, len));
}

bool stun_is_error_response_str(const uint8_t *buf, size_t len, int *err_code, uint8_t *err_msg, size_t err_msg_size) {
  if (is_channel_msg_str(buf, len)) {
    return false;
  }
  if (IS_STUN_ERR_RESP(stun_get_msg_type_str(buf, len))) {
    if (err_code) {
      stun_attr_ref sar = stun_attr_get_first_by_type_str(buf, len, STUN_ATTRIBUTE_ERROR_CODE);
      if (sar) {
        if (stun_attr_get_len(sar) >= 4) {
          const uint8_t *val = (const uint8_t *)stun_attr_get_value(sar);
          *err_code = (int)(val[2] * 100 + val[3]);
          if (err_msg && err_msg_size > 0) {
            err_msg[0] = 0;
            if (stun_attr_get_len(sar) > 4) {
              size_t msg_len = stun_attr_get_len(sar) - 4;
              if (msg_len > (err_msg_size - 1)) {
                msg_len = err_msg_size - 1;
              }
              memcpy(err_msg, val + 4, msg_len);
              err_msg[msg_len] = 0;
            }
          }
        }
      }
    }
    return true;
  }
  return false;
}

bool stun_is_challenge_response_str(const uint8_t *buf, size_t len, int *err_code, uint8_t *err_msg,
                                    size_t err_msg_size, uint8_t *realm, uint8_t *nonce, uint8_t *server_name,
                                    bool *oauth) {
  bool ret = stun_is_error_response_str(buf, len, err_code, err_msg, err_msg_size);

  if (ret && (((*err_code) == 401) || ((*err_code) == 438))) {
    stun_attr_ref sar = stun_attr_get_first_by_type_str(buf, len, STUN_ATTRIBUTE_REALM);
    if (sar) {
      bool found_oauth = false;

      const uint8_t *value = stun_attr_get_value(sar);
      if (value) {
        size_t vlen = (size_t)stun_attr_get_len(sar);
        vlen = min(vlen, (size_t)STUN_MAX_REALM_SIZE);
        memcpy(realm, value, vlen);
        realm[vlen] = 0;
        {
          sar = stun_attr_get_first_by_type_str(buf, len, STUN_ATTRIBUTE_THIRD_PARTY_AUTHORIZATION);
          if (sar) {
            value = stun_attr_get_value(sar);
            if (value) {
              vlen = (size_t)stun_attr_get_len(sar);
              vlen = min(vlen, (size_t)STUN_MAX_SERVER_NAME_SIZE);
              if (vlen > 0) {
                if (server_name) {
                  memcpy(server_name, value, vlen);
                }
                found_oauth = true;
              }
            }
          }
        }

        sar = stun_attr_get_first_by_type_str(buf, len, STUN_ATTRIBUTE_NONCE);
        if (sar) {
          value = stun_attr_get_value(sar);
          if (value) {
            vlen = (size_t)stun_attr_get_len(sar);
            vlen = min(vlen, (size_t)STUN_MAX_NONCE_SIZE);
            memcpy(nonce, value, vlen);
            nonce[vlen] = 0;
            if (oauth) {
              *oauth = found_oauth;
            }
            return true;
          }
        }
      }
    }
  }

  return false;
}

bool stun_is_response_str(const uint8_t *buf, size_t len) {
  if (is_channel_msg_str(buf, len)) {
    return false;
  }
  if (IS_STUN_SUCCESS_RESP(stun_get_msg_type_str(buf, len))) {
    return true;
  }
  if (IS_STUN_ERR_RESP(stun_get_msg_type_str(buf, len))) {
    return true;
  }
  return false;
}

bool stun_is_indication_str(const uint8_t *buf, size_t len) {
  if (is_channel_msg_str(buf, len)) {
    return false;
  }
  return IS_STUN_INDICATION(stun_get_msg_type_str(buf, len));
}

uint16_t stun_make_request(uint16_t method) { return GET_STUN_REQUEST(stun_make_type(method)); }

uint16_t stun_make_indication(uint16_t method) { return GET_STUN_INDICATION(stun_make_type(method)); }

uint16_t stun_make_success_response(uint16_t method) { return GET_STUN_SUCCESS_RESP(stun_make_type(method)); }

uint16_t stun_make_error_response(uint16_t method) { return GET_STUN_ERR_RESP(stun_make_type(method)); }

//////////////// INIT ////////////////////////////////////////////

void stun_init_buffer_str(uint8_t *buf, size_t *len) {
  *len = STUN_HEADER_LENGTH;
  memset(buf, 0, *len);
}

void stun_init_command_str(uint16_t message_type, uint8_t *buf, size_t *len) {
  stun_init_buffer_str(buf, len);
  message_type &= (uint16_t)(0x3FFF);
  ((uint16_t *)buf)[0] = nswap16(message_type);
  ((uint16_t *)buf)[1] = 0;
  ((uint32_t *)buf)[1] = nswap32(STUN_MAGIC_COOKIE);
  stun_tid_generate_in_message_str(buf, NULL);
}

void old_stun_init_command_str(uint16_t message_type, uint8_t *buf, size_t *len, uint32_t cookie) {
  stun_init_buffer_str(buf, len);
  message_type &= (uint16_t)(0x3FFF);
  ((uint16_t *)buf)[0] = nswap16(message_type);
  ((uint16_t *)buf)[1] = 0;
  ((uint32_t *)buf)[1] = nswap32(cookie);
  stun_tid_generate_in_message_str(buf, NULL);
}

void stun_init_request_str(uint16_t method, uint8_t *buf, size_t *len) {
  stun_init_command_str(stun_make_request(method), buf, len);
}

void stun_init_indication_str(uint16_t method, uint8_t *buf, size_t *len) {
  stun_init_command_str(stun_make_indication(method), buf, len);
}

void stun_init_success_response_str(uint16_t method, uint8_t *buf, size_t *len, stun_tid *id) {
  stun_init_command_str(stun_make_success_response(method), buf, len);
  if (id) {
    stun_tid_message_cpy(buf, id);
  }
}

void old_stun_init_success_response_str(uint16_t method, uint8_t *buf, size_t *len, stun_tid *id, uint32_t cookie) {
  old_stun_init_command_str(stun_make_success_response(method), buf, len, cookie);
  if (id) {
    stun_tid_message_cpy(buf, id);
  }
}

const uint8_t *get_default_reason(int error_code) {
  const char *reason = "Unknown error";

  switch (error_code) {
  case 300:
    reason = "Try Alternate";
    break;
  case 400:
    reason = "Bad Request";
    break;
  case 401:
    reason = "Unauthorized";
    break;
  case 403:
    reason = "Forbidden";
    break;
  case 404:
    reason = "Not Found";
    break;
  case 420:
    reason = "Unknown Attribute";
    break;
  case 437:
    reason = "Allocation Mismatch";
    break;
  case 438:
    reason = "Stale Nonce";
    break;
  case 440:
    reason = "Address Family not Supported";
    break;
  case 441:
    reason = "Wrong Credentials";
    break;
  case 442:
    reason = "Unsupported Transport Protocol";
    break;
  case 443:
    reason = "Peer Address Family Mismatch";
    break;
  case 446:
    reason = "Connection Already Exists";
    break;
  case 447:
    reason = "Connection Timeout or Failure";
    break;
  case 486:
    reason = "Allocation Quota Reached";
    break;
  case 487:
    reason = "Role Conflict";
    break;
  case 500:
    reason = "Server Error";
    break;
  case 508:
    reason = "Insufficient Capacity";
    break;
  default:;
  };

  return (const uint8_t *)reason;
}

static void stun_init_error_response_common_str(uint8_t *buf, size_t *len, uint16_t error_code, const uint8_t *reason,
                                                stun_tid *id) {

  if (!reason || !strcmp((const char *)reason, "Unknown error")) {
    reason = get_default_reason(error_code);
  }

  uint8_t avalue[513];
  avalue[0] = 0;
  avalue[1] = 0;
  avalue[2] = (uint8_t)(error_code / 100);
  avalue[3] = (uint8_t)(error_code % 100);
  strncpy((char *)(avalue + 4), (const char *)reason, sizeof(avalue) - 4);
  avalue[sizeof(avalue) - 1] = 0;
  int alen = 4 + (int)strlen((const char *)(avalue + 4));

  //"Manual" padding for compatibility with classic old stun:
  {
    int rem = alen % 4;
    if (rem) {
      alen += (4 - rem);
    }
  }

  stun_attr_add_str(buf, len, STUN_ATTRIBUTE_ERROR_CODE, (uint8_t *)avalue, alen);
  if (id) {
    stun_tid_message_cpy(buf, id);
  }
}

void old_stun_init_error_response_str(uint16_t method, uint8_t *buf, size_t *len, uint16_t error_code,
                                      const uint8_t *reason, stun_tid *id, uint32_t cookie) {

  old_stun_init_command_str(stun_make_error_response(method), buf, len, cookie);

  stun_init_error_response_common_str(buf, len, error_code, reason, id);
}

void stun_init_error_response_str(uint16_t method, uint8_t *buf, size_t *len, uint16_t error_code,
                                  const uint8_t *reason, stun_tid *id) {

  stun_init_command_str(stun_make_error_response(method), buf, len);

  stun_init_error_response_common_str(buf, len, error_code, reason, id);
}

/////////// CHANNEL ////////////////////////////////////////////////

bool stun_init_channel_message_str(uint16_t chnumber, uint8_t *buf, size_t *len, int length, bool do_padding) {
  uint16_t rlen = (uint16_t)length;

  if (length < 0 || (MAX_STUN_MESSAGE_SIZE < (4 + length))) {
    return false;
  }
  ((uint16_t *)(buf))[0] = nswap16(chnumber);
  ((uint16_t *)(buf))[1] = nswap16((uint16_t)length);

  if (do_padding && (rlen & 0x0003)) {
    rlen = ((rlen >> 2) + 1) << 2;
  }

  *len = 4 + rlen;

  return true;
}

bool stun_is_channel_message_str(const uint8_t *buf, size_t *blen, uint16_t *chnumber, bool mandatory_padding) {
  uint16_t datalen_header;
  uint16_t datalen_actual;

  if (!blen || (*blen < 4)) {
    return false;
  }

  uint16_t chn = nswap16(((const uint16_t *)(buf))[0]);
  if (!STUN_VALID_CHANNEL(chn)) {
    return false;
  }

  if (*blen > (uint16_t)-1) {
    *blen = (uint16_t)-1;
  }

  datalen_actual = (uint16_t)(*blen) - 4;
  datalen_header = ((const uint16_t *)buf)[1];
  datalen_header = nswap16(datalen_header);

  if (datalen_header > datalen_actual) {
    return false;
  }

  if (datalen_header != datalen_actual) {

    /* maybe there are padding bytes for 32-bit alignment. Mandatory for TCP. Optional for UDP */

    if (datalen_actual & 0x0003) {

      if (mandatory_padding) {
        return false;
      } else if (datalen_header == 0) {
        return false;
      } else {
        uint16_t diff = datalen_actual - datalen_header;
        if (diff > 3) {
          return false;
        }
      }
    }
  }

  *blen = datalen_header + 4;

  if (chnumber) {
    *chnumber = chn;
  }

  return true;
}

////////// STUN message ///////////////////////////////

static inline bool sheadof(const char *head, const char *full, bool ignore_case) {
  while (*head) {
    if (*head != *full) {
      if (ignore_case && (tolower((int)*head) == tolower((int)*full))) {
        // OK
      } else {
        return false;
      }
    }
    ++head;
    ++full;
  }
  return true;
}

static inline const char *findstr(const char *hay, size_t slen, const char *needle, bool ignore_case) {
  const char *ret = NULL;

  if (hay && slen && needle) {
    size_t nlen = strlen(needle);
    if (nlen <= slen) {
      size_t smax = slen - nlen + 1;
      const char *sp = hay;
      for (size_t i = 0; i < smax; ++i) {
        if (sheadof(needle, sp + i, ignore_case)) {
          ret = sp + i;
          break;
        }
      }
    }
  }

  return ret;
}

int is_http(const char *s, size_t blen) {
  if (s && blen >= 12) {
    if ((strstr(s, "GET ") == s) || (strstr(s, "POST ") == s) || (strstr(s, "DELETE ") == s) ||
        (strstr(s, "PUT ") == s)) {
      const char *sp = findstr(s + 4, blen - 4, " HTTP/", false);
      if (sp) {
        sp += 6;
        size_t diff_blen = sp - s;
        if (diff_blen + 4 <= blen) {
          sp = findstr(sp, blen - diff_blen, "\r\n\r\n", false);
          if (sp) {
            int ret_len = (int)(sp - s + 4);
            const char *clheader = "content-length: ";
            const char *cl = findstr(s, sp - s, clheader, true);
            if (cl) {
              unsigned long clen = strtoul(cl + strlen(clheader), NULL, 10);
              if (clen > 0 && clen < (0x0FFFFFFF)) {
                ret_len += (int)clen;
              }
            }
            return ret_len;
          }
        }
      }
    }
  }
  return 0;
}

int stun_get_message_len_str(uint8_t *buf, size_t blen, int padding, size_t *app_len) {
  if (buf && blen) {
    /* STUN request/response ? */
    if (buf && blen >= STUN_HEADER_LENGTH) {
      if (!STUN_VALID_CHANNEL(nswap16(((const uint16_t *)buf)[0]))) {
        if ((((uint8_t)buf[0]) & ((uint8_t)(0xC0))) == 0) {
          if (nswap32(((const uint32_t *)(buf))[1]) == STUN_MAGIC_COOKIE) {
            uint16_t len = nswap16(((const uint16_t *)(buf))[1]);
            if ((len & 0x0003) == 0) {
              len += STUN_HEADER_LENGTH;
              if ((size_t)len <= blen) {
                *app_len = (size_t)len;
                return (int)len;
              }
            }
          }
        }
      }
    }

    // HTTP request ?
    {
      int http_len = is_http(((char *)buf), blen);
      if ((http_len > 0) && ((size_t)http_len <= blen)) {
        *app_len = (size_t)http_len;
        return http_len;
      }
    }

    /* STUN channel ? */
    if (blen >= 4) {
      uint16_t chn = nswap16(((const uint16_t *)(buf))[0]);
      if (STUN_VALID_CHANNEL(chn)) {

        uint16_t bret = (4 + (nswap16(((const uint16_t *)(buf))[1])));

        *app_len = bret;

        if (padding && (bret & 0x0003)) {
          bret = ((bret >> 2) + 1) << 2;
        }

        if (bret <= blen) {
          return bret;
        }
      }
    }
  }

  return -1;
}

////////// ALLOCATE ///////////////////////////////////

bool stun_set_allocate_request_str(uint8_t *buf, size_t *len, uint32_t lifetime, bool af4, bool af6, uint8_t transport,
                                   bool mobile, const char *rt, int ep) {

  stun_init_request_str(STUN_METHOD_ALLOCATE, buf, len);

  // REQUESTED-TRANSPORT
  {
    uint8_t field[4];
    field[0] = transport;
    field[1] = 0;
    field[2] = 0;
    field[3] = 0;
    if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_REQUESTED_TRANSPORT, field, sizeof(field))) {
      return false;
    }
  }

  // LIFETIME
  {
    if (lifetime < 1) {
      lifetime = STUN_DEFAULT_ALLOCATE_LIFETIME;
    }
    uint32_t field = nswap32(lifetime);
    if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_LIFETIME, (uint8_t *)(&field), sizeof(field))) {
      return false;
    }
  }

  // MICE
  if (mobile) {
    if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_MOBILITY_TICKET, (const uint8_t *)"", 0)) {
      return false;
    }
  }

  if (ep > -1) {
    uint8_t value = ep ? 0x80 : 0x00;
    if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_EVEN_PORT, (const uint8_t *)&value, 1)) {
      return false;
    }
  }

  // RESERVATION-TOKEN, EVEN-PORT and DUAL-ALLOCATION are mutually exclusive:
  if (rt) {

    stun_attr_add_str(buf, len, STUN_ATTRIBUTE_RESERVATION_TOKEN, (const uint8_t *)rt, 8);

  } else {

    // ADRESS-FAMILY
    if (af4 && !af6) {
      uint8_t field[4];
      field[0] = (uint8_t)STUN_ATTRIBUTE_REQUESTED_ADDRESS_FAMILY_VALUE_IPV4;
      field[1] = 0;
      field[2] = 0;
      field[3] = 0;
      if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_REQUESTED_ADDRESS_FAMILY, field, sizeof(field))) {
        return false;
      }
    }

    if (af6 && !af4) {
      uint8_t field[4];
      field[0] = (uint8_t)STUN_ATTRIBUTE_REQUESTED_ADDRESS_FAMILY_VALUE_IPV6;
      field[1] = 0;
      field[2] = 0;
      field[3] = 0;
      if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_REQUESTED_ADDRESS_FAMILY, field, sizeof(field))) {
        return false;
      }
    }

    if (af4 && af6) {
      uint8_t field[4];
      field[0] = (uint8_t)STUN_ATTRIBUTE_REQUESTED_ADDRESS_FAMILY_VALUE_IPV6;
      field[1] = 0;
      field[2] = 0;
      field[3] = 0;
      if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_ADDITIONAL_ADDRESS_FAMILY, field, sizeof(field))) {
        return false;
      }
    }
  }

  return true;
}

bool stun_set_allocate_response_str(uint8_t *buf, size_t *len, stun_tid *tid, const ioa_addr *relayed_addr1,
                                    const ioa_addr *relayed_addr2, const ioa_addr *reflexive_addr, uint32_t lifetime,
                                    uint32_t max_lifetime, int error_code, const uint8_t *reason,
                                    uint64_t reservation_token, char *mobile_id) {

  if (!error_code) {

    stun_init_success_response_str(STUN_METHOD_ALLOCATE, buf, len, tid);

    if (relayed_addr1) {
      if (!stun_attr_add_addr_str(buf, len, STUN_ATTRIBUTE_XOR_RELAYED_ADDRESS, relayed_addr1)) {
        return false;
      }
    }

    if (relayed_addr2) {
      if (!stun_attr_add_addr_str(buf, len, STUN_ATTRIBUTE_XOR_RELAYED_ADDRESS, relayed_addr2)) {
        return false;
      }
    }

    if (reflexive_addr) {
      if (!stun_attr_add_addr_str(buf, len, STUN_ATTRIBUTE_XOR_MAPPED_ADDRESS, reflexive_addr)) {
        return false;
      }
    }

    if (reservation_token) {
      reservation_token = nswap64(reservation_token);
      stun_attr_add_str(buf, len, STUN_ATTRIBUTE_RESERVATION_TOKEN, (uint8_t *)(&reservation_token), 8);
    }

    {
      if (lifetime < 1) {
        lifetime = STUN_DEFAULT_ALLOCATE_LIFETIME;
      } else if (lifetime > max_lifetime) {
        lifetime = max_lifetime;
      }

      uint32_t field = nswap32(lifetime);
      if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_LIFETIME, (uint8_t *)(&field), sizeof(field))) {
        return false;
      }
    }

    if (mobile_id && *mobile_id) {
      if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_MOBILITY_TICKET, (uint8_t *)mobile_id, (int)strlen(mobile_id))) {
        return false;
      }
    }

  } else {
    stun_init_error_response_str(STUN_METHOD_ALLOCATE, buf, len, error_code, reason, tid);
  }

  return true;
}

/////////////// CHANNEL BIND ///////////////////////////////////////

uint16_t stun_set_channel_bind_request_str(uint8_t *buf, size_t *len, const ioa_addr *peer_addr,
                                           uint16_t channel_number) {

  if (!STUN_VALID_CHANNEL(channel_number)) {
    channel_number = 0x4000 + ((uint16_t)(((uint32_t)turn_random_number()) % (0x7FFF - 0x4000 + 1)));
  }

  stun_init_request_str(STUN_METHOD_CHANNEL_BIND, buf, len);

  if (!stun_attr_add_channel_number_str(buf, len, channel_number)) {
    return 0;
  }

  if (!peer_addr) {
    ioa_addr ca;
    memset(&ca, 0, sizeof(ioa_addr));

    if (!stun_attr_add_addr_str(buf, len, STUN_ATTRIBUTE_XOR_PEER_ADDRESS, &ca)) {
      return 0;
    }
  } else {
    if (!stun_attr_add_addr_str(buf, len, STUN_ATTRIBUTE_XOR_PEER_ADDRESS, peer_addr)) {
      return 0;
    }
  }

  return channel_number;
}

void stun_set_channel_bind_response_str(uint8_t *buf, size_t *len, stun_tid *tid, int error_code,
                                        const uint8_t *reason) {
  if (!error_code) {
    stun_init_success_response_str(STUN_METHOD_CHANNEL_BIND, buf, len, tid);
  } else {
    stun_init_error_response_str(STUN_METHOD_CHANNEL_BIND, buf, len, error_code, reason, tid);
  }
}

/////////////// BINDING ///////////////////////////////////////

void stun_set_binding_request_str(uint8_t *buf, size_t *len) { stun_init_request_str(STUN_METHOD_BINDING, buf, len); }

bool stun_set_binding_response_str(uint8_t *buf, size_t *len, stun_tid *tid, const ioa_addr *reflexive_addr,
                                   int error_code, const uint8_t *reason, uint32_t cookie, bool old_stun,
                                   bool stun_backward_compatibility)

{
  if (!error_code) {
    if (!old_stun) {
      stun_init_success_response_str(STUN_METHOD_BINDING, buf, len, tid);
    } else {
      old_stun_init_success_response_str(STUN_METHOD_BINDING, buf, len, tid, cookie);
    }
    if (!old_stun && reflexive_addr) {
      if (!stun_attr_add_addr_str(buf, len, STUN_ATTRIBUTE_XOR_MAPPED_ADDRESS, reflexive_addr)) {
        return false;
      }
    }
    if (reflexive_addr) {
      if (stun_backward_compatibility &&
          !stun_attr_add_addr_str(buf, len, STUN_ATTRIBUTE_MAPPED_ADDRESS, reflexive_addr)) {
        return false;
      }
    }
  } else if (!old_stun) {
    stun_init_error_response_str(STUN_METHOD_BINDING, buf, len, error_code, reason, tid);
  } else {
    old_stun_init_error_response_str(STUN_METHOD_BINDING, buf, len, error_code, reason, tid, cookie);
  }

  return true;
}

bool stun_is_binding_request_str(const uint8_t *buf, size_t len, size_t offset) {
  if (offset < len) {
    buf += offset;
    len -= offset;
    if (stun_is_command_message_str(buf, len)) {
      if (stun_is_request_str(buf, len) && (stun_get_method_str(buf, len) == STUN_METHOD_BINDING)) {
        return true;
      }
    }
  }
  return false;
}

bool stun_is_binding_response_str(const uint8_t *buf, size_t len) {
  if (stun_is_command_message_str(buf, len) && (stun_get_method_str(buf, len) == STUN_METHOD_BINDING)) {
    if (stun_is_response_str(buf, len)) {
      return true;
    }
  }
  return false;
}

/////////////////////////////// TID ///////////////////////////////

bool stun_tid_equals(const stun_tid *id1, const stun_tid *id2) {
  if (!id1 || !id2) {
    return false;
  }
  if (id1 == id2) {
    return true;
  }
  for (size_t i = 0; i < STUN_TID_SIZE; ++i) {
    if (id1->tsx_id[i] != id2->tsx_id[i]) {
      return false;
    }
  }
  return true;
}

void stun_tid_cpy(stun_tid *id1, const stun_tid *id2) {
  if (!id1 || !id2) {
    return;
  }
  memcpy(id1->tsx_id, id2->tsx_id, STUN_TID_SIZE);
}

static void stun_tid_string_cpy(uint8_t *s, const stun_tid *id) {
  if (s && id) {
    memcpy(s, id->tsx_id, STUN_TID_SIZE);
  }
}

static void stun_tid_from_string(const uint8_t *s, stun_tid *id) {
  if (s && id) {
    memcpy(id->tsx_id, s, STUN_TID_SIZE);
  }
}

void stun_tid_from_message_str(const uint8_t *buf, size_t len, stun_tid *id) {
  UNUSED_ARG(len);
  stun_tid_from_string(buf + 8, id);
}

void stun_tid_message_cpy(uint8_t *buf, const stun_tid *id) {
  if (buf && id) {
    stun_tid_string_cpy(buf + 8, id);
  }
}

void stun_tid_generate(stun_tid *id) {
  if (id) {
    turn_random_tid_size(id->tsx_id);
  }
}

void stun_tid_generate_in_message_str(uint8_t *buf, stun_tid *id) {
  stun_tid tmp;
  if (!id) {
    id = &tmp;
  }
  stun_tid_generate(id);
  stun_tid_message_cpy(buf, id);
}

/////////////////// TIME ////////////////////////////////////////////////////////

turn_time_t stun_adjust_allocate_lifetime(turn_time_t lifetime, turn_time_t max_allowed_lifetime,
                                          turn_time_t max_lifetime) {

  if (!lifetime) {
    lifetime = STUN_DEFAULT_ALLOCATE_LIFETIME;
  } else if (lifetime < STUN_MIN_ALLOCATE_LIFETIME) {
    lifetime = STUN_MIN_ALLOCATE_LIFETIME;
  } else if (lifetime > max_allowed_lifetime) {
    lifetime = max_allowed_lifetime;
  }

  if (max_lifetime && (max_lifetime < lifetime)) {
    lifetime = max_lifetime;
  }

  return lifetime;
}

////////////// ATTR /////////////////////////////////////////////////////////////

int stun_attr_get_type(stun_attr_ref attr) {
  if (attr) {
    return (int)(nswap16(((const uint16_t *)attr)[0]));
  }
  return -1;
}

int stun_attr_get_len(stun_attr_ref attr) {
  if (attr) {
    return (int)(nswap16(((const uint16_t *)attr)[1]));
  }
  return -1;
}

const uint8_t *stun_attr_get_value(stun_attr_ref attr) {
  if (attr) {
    int len = (int)(nswap16(((const uint16_t *)attr)[1]));
    if (len < 1) {
      return NULL;
    }
    return ((const uint8_t *)attr) + 4;
  }
  return NULL;
}

int stun_get_requested_address_family(stun_attr_ref attr) {
  if (attr) {
    int len = (int)(nswap16(((const uint16_t *)attr)[1]));
    if (len != 4) {
      return STUN_ATTRIBUTE_REQUESTED_ADDRESS_FAMILY_VALUE_INVALID;
    }
    int val = ((const uint8_t *)attr)[4];
    switch (val) {
    case STUN_ATTRIBUTE_REQUESTED_ADDRESS_FAMILY_VALUE_IPV4:
    case STUN_ATTRIBUTE_REQUESTED_ADDRESS_FAMILY_VALUE_IPV6:
      return val;
    default:
      return STUN_ATTRIBUTE_REQUESTED_ADDRESS_FAMILY_VALUE_INVALID;
    };
  }
  return STUN_ATTRIBUTE_REQUESTED_ADDRESS_FAMILY_VALUE_DEFAULT;
}

uint16_t stun_attr_get_channel_number(stun_attr_ref attr) {
  if (attr) {
    const uint8_t *value = stun_attr_get_value(attr);
    if (value && (stun_attr_get_len(attr) >= 2)) {
      uint16_t cn = nswap16(((const uint16_t *)value)[0]);
      if (STUN_VALID_CHANNEL(cn)) {
        return cn;
      }
    }
  }
  return 0;
}

band_limit_t stun_attr_get_bandwidth(stun_attr_ref attr) {
  if (attr) {
    const uint8_t *value = stun_attr_get_value(attr);
    if (value && (stun_attr_get_len(attr) >= 4)) {
      uint32_t bps = nswap32(((const uint32_t *)value)[0]);
      return (band_limit_t)(bps << 7);
    }
  }
  return 0;
}

uint64_t stun_attr_get_reservation_token_value(stun_attr_ref attr) {
  if (attr) {
    const uint8_t *value = stun_attr_get_value(attr);
    if (value && (stun_attr_get_len(attr) == 8)) {
      uint64_t token;
      memcpy(&token, value, sizeof(uint64_t));
      return nswap64(token);
    }
  }
  return 0;
}

bool stun_attr_is_addr(stun_attr_ref attr) {

  if (attr) {
    switch (stun_attr_get_type(attr)) {
    case STUN_ATTRIBUTE_XOR_MAPPED_ADDRESS:
    case STUN_ATTRIBUTE_XOR_PEER_ADDRESS:
    case STUN_ATTRIBUTE_XOR_RELAYED_ADDRESS:
    case STUN_ATTRIBUTE_MAPPED_ADDRESS:
    case STUN_ATTRIBUTE_ALTERNATE_SERVER:
    case OLD_STUN_ATTRIBUTE_RESPONSE_ADDRESS:
    case OLD_STUN_ATTRIBUTE_SOURCE_ADDRESS:
    case OLD_STUN_ATTRIBUTE_CHANGED_ADDRESS:
    case OLD_STUN_ATTRIBUTE_REFLECTED_FROM:
    case STUN_ATTRIBUTE_RESPONSE_ORIGIN:
    case STUN_ATTRIBUTE_OTHER_ADDRESS:
      return true;
      break;
    default:;
    };
  }
  return false;
}

uint8_t stun_attr_get_even_port(stun_attr_ref attr) {
  if (attr) {
    const uint8_t *value = stun_attr_get_value(attr);
    if (value) {
      if ((uint8_t)(value[0]) > 0x7F) {
        return 1;
      }
    }
  }
  return 0;
}

stun_attr_ref stun_attr_get_first_by_type_str(const uint8_t *buf, size_t len, uint16_t attr_type) {
  stun_attr_ref attr = stun_attr_get_first_str(buf, len);
  while (attr) {
    if (stun_attr_get_type(attr) == attr_type) {
      return attr;
    }
    attr = stun_attr_get_next_str(buf, len, attr);
  }

  return NULL;
}

static stun_attr_ref stun_attr_check_valid(stun_attr_ref attr, size_t remaining) {
  if (remaining >= 4) {
    /* Read the size of the attribute */
    size_t attrlen = stun_attr_get_len(attr);
    remaining -= 4;

    /* Round to boundary */
    uint16_t rem4 = ((uint16_t)attrlen) & 0x0003;
    if (rem4) {
      attrlen = attrlen + 4 - (int)rem4;
    }

    /* Check that there's enough space remaining */
    if (attrlen <= remaining) {
      return attr;
    }
  }

  return NULL;
}

stun_attr_ref stun_attr_get_first_str(const uint8_t *buf, size_t len) {
  int bufLen = stun_get_command_message_len_str(buf, len);
  if (bufLen > STUN_HEADER_LENGTH) {
    stun_attr_ref attr = (stun_attr_ref)(buf + STUN_HEADER_LENGTH);
    return stun_attr_check_valid(attr, bufLen - STUN_HEADER_LENGTH);
  }

  return NULL;
}

stun_attr_ref stun_attr_get_next_str(const uint8_t *buf, size_t len, stun_attr_ref prev) {
  if (!prev) {
    return stun_attr_get_first_str(buf, len);
  } else {
    const uint8_t *end = buf + stun_get_command_message_len_str(buf, len);
    int attrlen = stun_attr_get_len(prev);
    uint16_t rem4 = ((uint16_t)attrlen) & 0x0003;
    if (rem4) {
      attrlen = attrlen + 4 - (int)rem4;
    }
    /* Note the order here: operations on attrlen are untrusted as they may overflow */
    if (attrlen < end - (const uint8_t *)prev - 4) {
      const uint8_t *attr_end = (const uint8_t *)prev + 4 + attrlen;
      return stun_attr_check_valid(attr_end, end - attr_end);
    }
    return NULL;
  }
}

bool stun_attr_add_str(uint8_t *buf, size_t *len, uint16_t attr, const uint8_t *avalue, int alen) {
  if (alen < 0) {
    alen = 0;
  }
  uint8_t tmp[1];
  if (!avalue) {
    alen = 0;
    avalue = tmp;
  }
  int clen = stun_get_command_message_len_str(buf, *len);
  int newlen = clen + 4 + alen;
  int newlenrem4 = newlen & 0x00000003;
  int paddinglen = 0;
  if (newlenrem4) {
    paddinglen = 4 - newlenrem4;
    newlen = newlen + paddinglen;
  }

  if (newlen >= MAX_STUN_MESSAGE_SIZE) {
    return false;
  }

  uint8_t *attr_start = buf + clen;

  uint16_t *attr_start_16t = (uint16_t *)attr_start;

  stun_set_command_message_len_str(buf, newlen);
  *len = newlen;

  attr_start_16t[0] = nswap16(attr);
  attr_start_16t[1] = nswap16(alen);
  if (alen > 0) {
    memcpy(attr_start + 4, avalue, alen);
  }

  // Write 0 padding to not leak data
  memset(attr_start + 4 + alen, 0, paddinglen);

  return true;
}

bool stun_attr_add_addr_str(uint8_t *buf, size_t *len, uint16_t attr_type, const ioa_addr *ca) {

  stun_tid tid;
  stun_tid_from_message_str(buf, *len, &tid);

  int xor_ed = 0;
  switch (attr_type) {
  case STUN_ATTRIBUTE_XOR_MAPPED_ADDRESS:
  case STUN_ATTRIBUTE_XOR_PEER_ADDRESS:
  case STUN_ATTRIBUTE_XOR_RELAYED_ADDRESS:
    xor_ed = 1;
    break;
  default:;
  };

  ioa_addr public_addr;
  map_addr_from_private_to_public(ca, &public_addr);

  uint8_t cfield[64];
  int clen = 0;
  if (stun_addr_encode(&public_addr, cfield, &clen, xor_ed, STUN_MAGIC_COOKIE, tid.tsx_id) < 0) {
    return false;
  }

  if (!stun_attr_add_str(buf, len, attr_type, (uint8_t *)(&cfield), clen)) {
    return false;
  }

  return true;
}

bool stun_attr_get_addr_str(const uint8_t *buf, size_t len, stun_attr_ref attr, ioa_addr *ca,
                            const ioa_addr *default_addr) {
  stun_tid tid;
  stun_tid_from_message_str(buf, len, &tid);
  ioa_addr public_addr;

  addr_set_any(ca);
  addr_set_any(&public_addr);

  int attr_type = stun_attr_get_type(attr);
  if (attr_type < 0) {
    return false;
  }

  int xor_ed = 0;
  switch (attr_type) {
  case STUN_ATTRIBUTE_XOR_MAPPED_ADDRESS:
  case STUN_ATTRIBUTE_XOR_PEER_ADDRESS:
  case STUN_ATTRIBUTE_XOR_RELAYED_ADDRESS:
    xor_ed = 1;
    break;
  default:;
  };

  const uint8_t *cfield = stun_attr_get_value(attr);
  if (!cfield) {
    return false;
  }

  if (stun_addr_decode(&public_addr, cfield, stun_attr_get_len(attr), xor_ed, STUN_MAGIC_COOKIE, tid.tsx_id) < 0) {
    return false;
  }

  map_addr_from_public_to_private(&public_addr, ca);

  if (default_addr && addr_any_no_port(ca) && !addr_any_no_port(default_addr)) {
    int port = addr_get_port(ca);
    addr_cpy(ca, default_addr);
    addr_set_port(ca, port);
  }

  return true;
}

bool stun_attr_get_first_addr_str(const uint8_t *buf, size_t len, uint16_t attr_type, ioa_addr *ca,
                                  const ioa_addr *default_addr) {
  stun_attr_ref attr = stun_attr_get_first_str(buf, len);

  while (attr) {
    if (stun_attr_is_addr(attr) && (attr_type == stun_attr_get_type(attr))) {
      if (stun_attr_get_addr_str(buf, len, attr, ca, default_addr)) {
        return true;
      }
    }
    attr = stun_attr_get_next_str(buf, len, attr);
  }

  return false;
}

bool stun_attr_add_channel_number_str(uint8_t *buf, size_t *len, uint16_t chnumber) {

  uint16_t field[2];
  field[0] = nswap16(chnumber);
  field[1] = 0;

  return stun_attr_add_str(buf, len, STUN_ATTRIBUTE_CHANNEL_NUMBER, (uint8_t *)(field), sizeof(field));
}

bool stun_attr_add_bandwidth_str(uint8_t *buf, size_t *len, band_limit_t bps0) {

  uint32_t bps = (uint32_t)(band_limit_t)(bps0 >> 7);

  uint32_t field = nswap32(bps);

  return stun_attr_add_str(buf, len, STUN_ATTRIBUTE_NEW_BANDWIDTH, (uint8_t *)(&field), sizeof(field));
}

bool stun_attr_add_address_error_code(uint8_t *buf, size_t *len, int requested_address_family, int error_code) {
  const uint8_t *reason = get_default_reason(error_code);

  uint8_t avalue[513];
  avalue[0] = (uint8_t)requested_address_family;
  avalue[1] = 0;
  avalue[2] = (uint8_t)(error_code / 100);
  avalue[3] = (uint8_t)(error_code % 100);
  strncpy((char *)(avalue + 4), (const char *)reason, sizeof(avalue) - 4);
  avalue[sizeof(avalue) - 1] = 0;
  int alen = 4 + (int)strlen((const char *)(avalue + 4));

  //"Manual" padding for compatibility with classic old stun:
  {
    int rem = alen % 4;
    if (rem) {
      alen += (4 - rem);
    }
  }

  return stun_attr_add_str(buf, len, STUN_ATTRIBUTE_ADDRESS_ERROR_CODE, (uint8_t *)avalue, alen);
}

uint16_t stun_attr_get_first_channel_number_str(const uint8_t *buf, size_t len) {

  stun_attr_ref attr = stun_attr_get_first_str(buf, len);
  while (attr) {
    if (stun_attr_get_type(attr) == STUN_ATTRIBUTE_CHANNEL_NUMBER) {
      uint16_t ret = stun_attr_get_channel_number(attr);
      if (STUN_VALID_CHANNEL(ret)) {
        return ret;
      }
    }
    attr = stun_attr_get_next_str(buf, len, attr);
  }

  return 0;
}

////////////// FINGERPRINT ////////////////////////////

bool stun_attr_add_fingerprint_str(uint8_t *buf, size_t *len) {
  uint32_t crc32 = 0;
  if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_FINGERPRINT, (uint8_t *)&crc32, 4)) {
    return false;
  }
  crc32 = ns_crc32(buf, (int)*len - 8);
  *((uint32_t *)(buf + *len - 4)) = nswap32(crc32 ^ ((uint32_t)FINGERPRINT_XOR));
  return true;
}
////////////// CRC ///////////////////////////////////////////////

#define CRC_MASK 0xFFFFFFFFUL

#define UPDATE_CRC(crc, c) crc = crctable[(uint8_t)crc ^ (uint8_t)(c)] ^ (crc >> 8)

static const uint32_t crctable[256] = {
    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832,
    0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
    0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, 0x646ba8c0, 0xfd62f97a,
    0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
    0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,
    0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
    0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab,
    0xb6662d3d, 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, 0x6b6b51f4,
    0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
    0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074,
    0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
    0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525,
    0x206f85b3, 0xb966d409, 0xce61e49f, 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
    0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,
    0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, 0xfed41b76,
    0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
    0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, 0x36034af6,
    0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
    0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7,
    0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
    0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7,
    0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,
    0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
    0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, 0xbdbdf21c, 0xcabac28a, 0x53b39330,
    0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
    0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d,
};

static uint32_t ns_crc32(const uint8_t *buffer, uint32_t len) {
  uint32_t crc = CRC_MASK;
  while (len--) {
    UPDATE_CRC(crc, *buffer++);
  }
  return (~crc);
}

//////////// SASLprep RFC 4013 /////////////////////////////////////////

/* We support only basic ASCII table */

bool SASLprep(uint8_t *s) {
  if (s) {
    uint8_t *strin = s;
    uint8_t *strout = s;
    for (;;) {
      uint8_t c = *strin;
      if (!c) {
        *strout = 0;
        break;
      }

      switch (c) {
      case 0xAD:
        ++strin;
        break;
      case 0xA0:
      case 0x20:
        *strout = 0x20;
        ++strout;
        ++strin;
        break;
      case 0x7F:
        return false;
      default:
        if (c < 0x1F) {
          return false;
        }
        if (c >= 0x80 && c <= 0x9F) {
          return false;
        }
        *strout = c;
        ++strout;
        ++strin;
      };
    }
  }

  return true;
}

//////////////// Message Integrity ////////////////////////////

size_t get_hmackey_size(SHATYPE shatype) {
  if (shatype == SHATYPE_SHA256) {
    return 32;
  }
  if (shatype == SHATYPE_SHA384) {
    return 48;
  }
  if (shatype == SHATYPE_SHA512) {
    return 64;
  }
  return 16;
}

void print_bin_func(const char *name, size_t len, const void *s, const char *func) {
  printf("<%s>:<%s>:len=%d:[", func, name, (int)len);
  for (size_t i = 0; i < len; i++) {
    printf("%02x", (int)((const uint8_t *)s)[i]);
  }
  printf("]\n");
}

bool stun_attr_add_integrity_str(turn_credential_type ct, uint8_t *buf, size_t *len, hmackey_t key, password_t pwd,
                                 SHATYPE shatype) {
  uint8_t hmac[MAXSHASIZE];

  unsigned int shasize;

  switch (shatype) {
  case SHATYPE_SHA256:
    shasize = SHA256SIZEBYTES;
    break;
  case SHATYPE_SHA384:
    shasize = SHA384SIZEBYTES;
    break;
  case SHATYPE_SHA512:
    shasize = SHA512SIZEBYTES;
    break;
  default:
    shasize = SHA1SIZEBYTES;
  };

  if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_MESSAGE_INTEGRITY, hmac, shasize)) {
    return false;
  }

  if (ct == TURN_CREDENTIALS_SHORT_TERM) {
    return stun_calculate_hmac(buf, *len - 4 - shasize, pwd, strlen((char *)pwd), buf + *len - shasize, &shasize,
                               shatype);
  } else {
    return stun_calculate_hmac(buf, *len - 4 - shasize, key, get_hmackey_size(shatype), buf + *len - shasize, &shasize,
                               shatype);
  }
}

bool stun_attr_add_integrity_by_key_str(uint8_t *buf, size_t *len, const uint8_t *uname, const uint8_t *realm,
                                        hmackey_t key, const uint8_t *nonce, SHATYPE shatype) {
  if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_USERNAME, uname, (int)strlen((const char *)uname))) {
    return false;
  }

  if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_NONCE, nonce, (int)strlen((const char *)nonce))) {
    return false;
  }

  if (!stun_attr_add_str(buf, len, STUN_ATTRIBUTE_REALM, realm, (int)strlen((const char *)realm))) {
    return false;
  }

  password_t p;
  return stun_attr_add_integrity_str(TURN_CREDENTIALS_LONG_TERM, buf, len, key, p, shatype);
}

bool stun_attr_add_integrity_by_user_str(uint8_t *buf, size_t *len, const uint8_t *uname, const uint8_t *realm,
                                         const uint8_t *upwd, const uint8_t *nonce, SHATYPE shatype) {
  hmackey_t key;

  if (!stun_produce_integrity_key_str(uname, realm, upwd, key, shatype)) {
    return false;
  }

  return stun_attr_add_integrity_by_key_str(buf, len, uname, realm, key, nonce, shatype);
}

bool stun_attr_add_integrity_by_user_short_term_str(uint8_t *buf, size_t *len, const uint8_t *uname, password_t pwd,
                                                    SHATYPE shatype) {
  if (stun_attr_add_str(buf, len, STUN_ATTRIBUTE_USERNAME, uname, (int)strlen((const char *)uname))) {
    return false;
  }

  hmackey_t key;
  return stun_attr_add_integrity_str(TURN_CREDENTIALS_SHORT_TERM, buf, len, key, pwd, shatype);
}

/*
 * Return -1 if failure, 0 if the integrity is not correct, 1 if OK
 */
int stun_check_message_integrity_by_key_str(turn_credential_type ct, uint8_t *buf, size_t len, hmackey_t key,
                                            password_t pwd, SHATYPE shatype) {
  stun_attr_ref sar = stun_attr_get_first_by_type_str(buf, len, STUN_ATTRIBUTE_MESSAGE_INTEGRITY);
  if (!sar) {
    return -1;
  }

  unsigned int shasize = 0;
  switch (stun_attr_get_len(sar)) {
  case SHA256SIZEBYTES:
    shasize = SHA256SIZEBYTES;
    if (shatype != SHATYPE_SHA256) {
      return -1;
    }
    break;
  case SHA384SIZEBYTES:
    shasize = SHA384SIZEBYTES;
    if (shatype != SHATYPE_SHA384) {
      return -1;
    }
    break;
  case SHA512SIZEBYTES:
    shasize = SHA512SIZEBYTES;
    if (shatype != SHATYPE_SHA512) {
      return -1;
    }
    break;
  case SHA1SIZEBYTES:
    shasize = SHA1SIZEBYTES;
    if (shatype != SHATYPE_SHA1) {
      return -1;
    }
    break;
  default:
    return -1;
  };

  int orig_len = stun_get_command_message_len_str(buf, len);
  if (orig_len < 0) {
    return -1;
  }

  int new_len = (int)((const uint8_t *)sar - buf) + 4 + shasize;
  if (new_len > orig_len) {
    return -1;
  }

  if (!stun_set_command_message_len_str(buf, new_len)) {
    return -1;
  }

  int res = 0;
  uint8_t new_hmac[MAXSHASIZE] = {0};
  if (ct == TURN_CREDENTIALS_SHORT_TERM) {
    if (!stun_calculate_hmac(buf, (size_t)new_len - 4 - shasize, pwd, strlen((char *)pwd), new_hmac, &shasize,
                             shatype)) {
      res = -1;
    } else {
      res = 0;
    }
  } else {
    if (!stun_calculate_hmac(buf, (size_t)new_len - 4 - shasize, key, get_hmackey_size(shatype), new_hmac, &shasize,
                             shatype)) {
      res = -1;
    } else {
      res = 0;
    }
  }

  stun_set_command_message_len_str(buf, orig_len);
  if (res < 0) {
    return -1;
  }

  const uint8_t *old_hmac = stun_attr_get_value(sar);
  if (!old_hmac) {
    return -1;
  }

  if (0 != memcmp(old_hmac, new_hmac, shasize)) {
    return 0;
  }

  return +1;
}

/*
 * Return -1 if failure, 0 if the integrity is not correct, 1 if OK
 */
int stun_check_message_integrity_str(turn_credential_type ct, uint8_t *buf, size_t len, const uint8_t *uname,
                                     const uint8_t *realm, const uint8_t *upwd, SHATYPE shatype) {
  hmackey_t key;
  password_t pwd;

  if (ct == TURN_CREDENTIALS_SHORT_TERM) {
    strncpy((char *)pwd, (const char *)upwd, sizeof(password_t) - 1);
    pwd[sizeof(password_t) - 1] = 0;
  } else if (!stun_produce_integrity_key_str(uname, realm, upwd, key, shatype)) {
    return -1;
  }

  return stun_check_message_integrity_by_key_str(ct, buf, len, key, pwd, shatype);
}

/* RFC 5780 */

bool stun_attr_get_change_request_str(stun_attr_ref attr, bool *change_ip, bool *change_port) {
  if (stun_attr_get_len(attr) == 4) {
    const uint8_t *value = stun_attr_get_value(attr);
    if (value) {
      *change_ip = (value[3] & 0x04);
      *change_port = (value[3] & 0x02);
      return true;
    }
  }
  return false;
}

bool stun_attr_add_change_request_str(uint8_t *buf, size_t *len, bool change_ip, bool change_port) {
  uint8_t avalue[4] = {0, 0, 0, 0};

  if (change_ip) {
    if (change_port) {
      avalue[3] = 0x06;
    } else {
      avalue[3] = 0x04;
    }
  } else if (change_port) {
    avalue[3] = 0x02;
  }

  return stun_attr_add_str(buf, len, STUN_ATTRIBUTE_CHANGE_REQUEST, avalue, 4);
}

int stun_attr_get_response_port_str(stun_attr_ref attr) {
  if (stun_attr_get_len(attr) >= 2) {
    const uint8_t *value = stun_attr_get_value(attr);
    if (value) {
      return nswap16(((const uint16_t *)value)[0]);
    }
  }
  return -1;
}

bool stun_attr_add_response_port_str(uint8_t *buf, size_t *len, uint16_t port) {
  uint8_t avalue[4] = {0, 0, 0, 0};
  uint16_t *port_ptr = (uint16_t *)avalue;

  *port_ptr = nswap16(port);

  return stun_attr_add_str(buf, len, STUN_ATTRIBUTE_RESPONSE_PORT, avalue, 4);
}

int stun_attr_get_padding_len_str(stun_attr_ref attr) {
  int len = stun_attr_get_len(attr);
  if (len < 0) {
    return -1;
  }
  return (uint16_t)len;
}

bool stun_attr_add_padding_str(uint8_t *buf, size_t *len, uint16_t padding_len) {
  uint8_t avalue[0xFFFF];
  memset(avalue, 0, padding_len);

  return stun_attr_add_str(buf, len, STUN_ATTRIBUTE_PADDING, avalue, padding_len);
}

/* OAUTH */

#define OAUTH_ERROR(...) fprintf(stderr, __VA_ARGS__)

static void remove_spaces(char *s) {
  char *sfns = s;
  while (*sfns) {
    if (*sfns != ' ') {
      break;
    }
    ++sfns;
  }
  if (*sfns) {
    if (sfns != s) {
      while (*sfns && (*sfns != ' ')) {
        *s = *sfns;
        ++s;
        ++sfns;
      };
      *s = 0;
    } else {
      while (*s) {
        if (*s == ' ') {
          *s = 0;
          break;
        }
        ++s;
      }
    }
  }
}

static void normalize_algorithm(char *s) {
  char c = *s;
  while (c) {
    if (c == '_') {
      *s = '-';
    } else if ((c >= 'a') && (c <= 'z')) {
      *s = c - 'a' + 'A';
    }
    ++s;
    c = *s;
  }
}

size_t calculate_enc_key_length(ENC_ALG a);
size_t calculate_enc_key_length(ENC_ALG a) {
  switch (a) {
#if !defined(TURN_NO_GCM)
  case A128GCM:
    return 16;
#endif
  default:
    break;
  };

  return 32;
}

size_t calculate_auth_key_length(ENC_ALG a);
size_t calculate_auth_key_length(ENC_ALG a) {
  switch (a) {
#if !defined(TURN_NO_GCM)
  case A256GCM:
  case A128GCM:
    return 0;
#endif
  default:
    break;
  };

  return 0;
}

static bool calculate_key(char *key, size_t key_size, char *new_key, size_t new_key_size);
static bool calculate_key(char *key, size_t key_size, char *new_key, size_t new_key_size) {
  UNUSED_ARG(key_size);

  memcpy(new_key, key, new_key_size);

  return true;
}

bool convert_oauth_key_data(const oauth_key_data *oakd0, oauth_key *key, char *err_msg, size_t err_msg_size) {
#if !defined(TURN_NO_OAUTH)
  if (oakd0 && key) {

    oauth_key_data oakd_obj;
    memcpy(&oakd_obj, oakd0, sizeof(oauth_key_data));
    oauth_key_data *oakd = &oakd_obj;

    if (!(oakd->ikm_key_size)) {
      if (err_msg) {
        snprintf(err_msg, err_msg_size, "key is not defined");
      }
    }

    remove_spaces(oakd->kid);

    remove_spaces(oakd->as_rs_alg);

    normalize_algorithm(oakd->as_rs_alg);

    if (!(oakd->kid[0])) {
      if (err_msg) {
        snprintf(err_msg, err_msg_size, "KID is not defined");
      }
      OAUTH_ERROR("KID is not defined\n");
      return false;
    }

    memset(key, 0, sizeof(oauth_key));

    STRCPY(key->kid, oakd->kid);

    memcpy(key->ikm_key, oakd->ikm_key, sizeof(key->ikm_key));
    key->ikm_key_size = oakd->ikm_key_size;

    key->timestamp = oakd->timestamp;
    key->lifetime = oakd->lifetime;

    if (!(key->timestamp)) {
      key->timestamp = OAUTH_DEFAULT_TIMESTAMP;
    }
    if (!(key->lifetime)) {
      key->lifetime = OAUTH_DEFAULT_LIFETIME;
    }

    key->as_rs_alg = ENC_ALG_ERROR;
#if !defined(TURN_NO_GCM)
    key->as_rs_alg = ENC_ALG_DEFAULT;
    if (!strcmp(oakd->as_rs_alg, "A128GCM")) {
      key->as_rs_alg = A128GCM;
      key->auth_key_size = 0;
      key->auth_key[0] = 0;
    } else if (!strcmp(oakd->as_rs_alg, "A256GCM")) {
      key->as_rs_alg = A256GCM;
      key->auth_key_size = 0;
      key->auth_key[0] = 0;
    } else
#endif
    {
      if (err_msg) {
        snprintf(err_msg, err_msg_size, "Wrong oAuth token encryption algorithm: %s (2)\n", oakd->as_rs_alg);
      }
      OAUTH_ERROR("Wrong oAuth token encryption algorithm: %s (3)\n", oakd->as_rs_alg);
      return false;
    }

#if !defined(TURN_NO_GCM)

    key->auth_key_size = calculate_auth_key_length(key->as_rs_alg);
    if (key->auth_key_size) {
      if (!calculate_key(key->ikm_key, key->ikm_key_size, key->auth_key, key->auth_key_size)) {
        return false;
      }
    }

    key->as_rs_key_size = calculate_enc_key_length(key->as_rs_alg);
    if (!calculate_key(key->ikm_key, key->ikm_key_size, key->as_rs_key, key->as_rs_key_size)) {
      return false;
    }
#endif
  }

  return true;
#else
  OAUTH_ERROR("Oauth support not included");
  return false;
#endif
}

#if !defined(TURN_NO_OAUTH)

const EVP_CIPHER *get_cipher_type(ENC_ALG enc_alg);
const EVP_CIPHER *get_cipher_type(ENC_ALG enc_alg) {
  switch (enc_alg) {
#if !defined(TURN_NO_GCM)
  case A128GCM:
    return EVP_aes_128_gcm();
  case A256GCM:
    return EVP_aes_256_gcm();
#endif
  default:
    break;
  }
  OAUTH_ERROR("%s: Unsupported enc algorithm: %d\n", __FUNCTION__, (int)enc_alg);
  return NULL;
}

int my_EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl, const unsigned char *in, int inl);
int my_EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl, const unsigned char *in, int inl) {
  int cycle = 0;
  int out_len = 0;
  while ((out_len < inl) && (++cycle < 128)) {
    int tmp_outl = 0;
    unsigned char *ptr = NULL;
    if (out) {
      ptr = out + out_len;
    }
    int ret = EVP_EncryptUpdate(ctx, ptr, &tmp_outl, in + out_len, inl - out_len);
    out_len += tmp_outl;
    if (ret < 1) {
      return ret;
    }
  }
  *outl = out_len;
  return 1;
}

int my_EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl, const unsigned char *in, int inl);
int my_EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl, const unsigned char *in, int inl) {
  int cycle = 0;
  int out_len = 0;
  while ((out_len < inl) && (++cycle < 128)) {
    int tmp_outl = 0;
    unsigned char *ptr = NULL;
    if (out) {
      ptr = out + out_len;
    }
    int ret = EVP_DecryptUpdate(ctx, ptr, &tmp_outl, in + out_len, inl - out_len);
    out_len += tmp_outl;
    if (ret < 1) {
      return ret;
    }
  }
  *outl = out_len;
  return 1;
}
#if !defined(TURN_NO_GCM)

static bool encode_oauth_token_gcm(const uint8_t *server_name, encoded_oauth_token *etoken, const oauth_key *key,
                                   const oauth_token *dtoken, const uint8_t *nonce0) {
  if (server_name && etoken && key && dtoken && (dtoken->enc_block.key_length <= MAXSHASIZE)) {

    unsigned char orig_field[MAX_ENCODED_OAUTH_TOKEN_SIZE];
    memset(orig_field, 0, sizeof(orig_field));

    unsigned char nonce[OAUTH_GCM_NONCE_SIZE];
    if (nonce0) {
      memcpy(nonce, nonce0, sizeof(nonce));
    } else {
      generate_random_nonce(nonce, sizeof(nonce));
    }

    size_t len = 0;

    *((uint16_t *)(orig_field + len)) = nswap16(OAUTH_GCM_NONCE_SIZE);
    len += 2;

    memcpy(orig_field + len, nonce, OAUTH_GCM_NONCE_SIZE);
    len += OAUTH_GCM_NONCE_SIZE;

    *((uint16_t *)(orig_field + len)) = nswap16(dtoken->enc_block.key_length);
    len += 2;

    memcpy(orig_field + len, dtoken->enc_block.mac_key, dtoken->enc_block.key_length);
    len += dtoken->enc_block.key_length;

    uint64_t ts = nswap64(dtoken->enc_block.timestamp);
    memcpy((orig_field + len), &ts, sizeof(ts));
    len += sizeof(ts);

    *((uint32_t *)(orig_field + len)) = nswap32(dtoken->enc_block.lifetime);
    len += 4;

    const EVP_CIPHER *cipher = get_cipher_type(key->as_rs_alg);
    if (!cipher) {
      return false;
    }

    EVP_CIPHER_CTX *ctxp = EVP_CIPHER_CTX_new();
    EVP_CIPHER_CTX_init(ctxp);

    /* Initialize the encryption operation. */
    if (1 != EVP_EncryptInit_ex(ctxp, cipher, NULL, NULL, NULL)) {
      return -1;
    }

    EVP_CIPHER_CTX_set_padding(ctxp, 1);

    /* Set IV length if default 12 bytes (96 bits) is not appropriate */
    if (1 != EVP_CIPHER_CTX_ctrl(ctxp, EVP_CTRL_GCM_SET_IVLEN, OAUTH_GCM_NONCE_SIZE, NULL)) {
      return false;
    }

    /* Initialize key and IV */
    if (1 != EVP_EncryptInit_ex(ctxp, NULL, NULL, (const unsigned char *)key->as_rs_key, nonce)) {
      return false;
    }

    int outl = 0;
    size_t sn_len = strlen((const char *)server_name);

    /* Provide any AAD data. This can be called zero or more times as
     * required
     */
    if (1 != my_EVP_EncryptUpdate(ctxp, NULL, &outl, server_name, (int)sn_len)) {
      return false;
    }

    outl = 0;
    unsigned char *encoded_field = (unsigned char *)etoken->token;
    memcpy(encoded_field, orig_field, OAUTH_GCM_NONCE_SIZE + 2);
    encoded_field += OAUTH_GCM_NONCE_SIZE + 2;
    unsigned char *start_field = orig_field + OAUTH_GCM_NONCE_SIZE + 2;
    len -= OAUTH_GCM_NONCE_SIZE + 2;

    if (1 != my_EVP_EncryptUpdate(ctxp, encoded_field, &outl, start_field, (int)len)) {
      return -1;
    }

    int tmp_outl = 0;
    EVP_EncryptFinal_ex(ctxp, encoded_field + outl, &tmp_outl);
    outl += tmp_outl;

    EVP_CIPHER_CTX_ctrl(ctxp, EVP_CTRL_GCM_GET_TAG, OAUTH_GCM_TAG_SIZE, encoded_field + outl);
    outl += OAUTH_GCM_TAG_SIZE;

    etoken->size = 2 + OAUTH_GCM_NONCE_SIZE + outl;

    EVP_CIPHER_CTX_free(ctxp);

    return true;
  }
  return false;
}

static bool decode_oauth_token_gcm(const uint8_t *server_name, const encoded_oauth_token *etoken, const oauth_key *key,
                                   oauth_token *dtoken) {
  if (server_name && etoken && key && dtoken) {

    unsigned char snl[2];
    memcpy(snl, (const unsigned char *)(etoken->token), 2);
    const unsigned char *csnl = snl;

    uint16_t nonce_len = nswap16(*((const uint16_t *)csnl));
    dtoken->enc_block.nonce_length = nonce_len;

    size_t min_encoded_field_size = 2 + 4 + 8 + nonce_len + 2 + OAUTH_GCM_TAG_SIZE + 1;
    if (etoken->size < min_encoded_field_size) {
      OAUTH_ERROR("%s: token size too small: %d\n", __FUNCTION__, (int)etoken->size);
      return false;
    }

    const unsigned char *encoded_field = (const unsigned char *)(etoken->token + nonce_len + 2);
    unsigned int encoded_field_size = (unsigned int)etoken->size - nonce_len - 2 - OAUTH_GCM_TAG_SIZE;
    const unsigned char *nonce = ((const unsigned char *)etoken->token + 2);
    memcpy(dtoken->enc_block.nonce, nonce, nonce_len);

    unsigned char tag[OAUTH_GCM_TAG_SIZE];
    memcpy(tag, ((const unsigned char *)etoken->token) + nonce_len + 2 + encoded_field_size, sizeof(tag));

    unsigned char decoded_field[MAX_ENCODED_OAUTH_TOKEN_SIZE];

    const EVP_CIPHER *cipher = get_cipher_type(key->as_rs_alg);
    if (!cipher) {
      OAUTH_ERROR("%s: Cannot find cipher for algorithm: %d\n", __FUNCTION__, (int)key->as_rs_alg);
      return false;
    }

    EVP_CIPHER_CTX *ctxp = EVP_CIPHER_CTX_new();
    EVP_CIPHER_CTX_init(ctxp);
    /* Initialize the decryption operation. */
    if (1 != EVP_DecryptInit_ex(ctxp, cipher, NULL, NULL, NULL)) {
      OAUTH_ERROR("%s: Cannot initialize decryption\n", __FUNCTION__);
      return false;
    }

    // EVP_CIPHER_CTX_set_padding(&ctx,1);

    /* Set IV length if default 12 bytes (96 bits) is not appropriate */
    if (1 != EVP_CIPHER_CTX_ctrl(ctxp, EVP_CTRL_GCM_SET_IVLEN, nonce_len, NULL)) {
      OAUTH_ERROR("%s: Cannot set nonce length\n", __FUNCTION__);
      return false;
    }

    /* Initialize key and IV */
    if (1 != EVP_DecryptInit_ex(ctxp, NULL, NULL, (const unsigned char *)key->as_rs_key, nonce)) {
      OAUTH_ERROR("%s: Cannot set nonce\n", __FUNCTION__);
      return false;
    }

    /* Set expected tag value. A restriction in OpenSSL 1.0.1c and earlier
      +         * required the tag before any AAD or ciphertext */
    EVP_CIPHER_CTX_ctrl(ctxp, EVP_CTRL_GCM_SET_TAG, OAUTH_GCM_TAG_SIZE, tag);

    int outl = 0;
    size_t sn_len = strlen((const char *)server_name);

    /* Provide any AAD data. This can be called zero or more times as
     * required
     */
    if (1 != my_EVP_DecryptUpdate(ctxp, NULL, &outl, server_name, (int)sn_len)) {
      OAUTH_ERROR("%s: Cannot decrypt update server_name: %s, len=%d\n", __FUNCTION__, server_name, (int)sn_len);
      return false;
    }
    if (1 != my_EVP_DecryptUpdate(ctxp, decoded_field, &outl, encoded_field, (int)encoded_field_size)) {
      OAUTH_ERROR("%s: Cannot decrypt update\n", __FUNCTION__);
      return false;
    }

    int tmp_outl = 0;
    if (EVP_DecryptFinal_ex(ctxp, decoded_field + outl, &tmp_outl) < 1) {
      EVP_CIPHER_CTX_free(ctxp);
      OAUTH_ERROR("%s: token integrity check failed\n", __FUNCTION__);
      return false;
    }
    outl += tmp_outl;

    EVP_CIPHER_CTX_free(ctxp);

    size_t len = 0;

    dtoken->enc_block.key_length = nswap16(*((uint16_t *)(decoded_field + len)));
    len += 2;

    memcpy(dtoken->enc_block.mac_key, decoded_field + len, dtoken->enc_block.key_length);
    len += dtoken->enc_block.key_length;

    uint64_t ts;
    memcpy(&ts, (decoded_field + len), sizeof(ts));
    dtoken->enc_block.timestamp = nswap64(ts);
    len += sizeof(ts);

    uint32_t lt;
    memcpy(&lt, (decoded_field + len), sizeof(lt));
    dtoken->enc_block.lifetime = nswap32(lt);
    len += sizeof(lt);

    return true;
  }
  return false;
}

#endif

#endif

bool encode_oauth_token(const uint8_t *server_name, encoded_oauth_token *etoken, const oauth_key *key,
                        const oauth_token *dtoken, const uint8_t *nonce) {
#if !defined(TURN_NO_OAUTH)
  UNUSED_ARG(nonce);
  if (server_name && etoken && key && dtoken) {
    switch (key->as_rs_alg) {
#if !defined(TURN_NO_GCM)
    case A256GCM:
    case A128GCM:
      return encode_oauth_token_gcm(server_name, etoken, key, dtoken, nonce);
#endif
    default:
      fprintf(stderr, "Unsupported AS_RS algorithm: %d\n", (int)key->as_rs_alg);
      break;
    };
  }
  return false;
#else
  OAUTH_ERROR("Oauth support not included");
  return false;
#endif
}

bool decode_oauth_token(const uint8_t *server_name, const encoded_oauth_token *etoken, const oauth_key *key,
                        oauth_token *dtoken) {
#if !defined(TURN_NO_OAUTH)
  if (server_name && etoken && key && dtoken) {
    switch (key->as_rs_alg) {
#if !defined(TURN_NO_GCM)
    case A256GCM:
    case A128GCM:
      return decode_oauth_token_gcm(server_name, etoken, key, dtoken);
#endif
    default:
      fprintf(stderr, "Unsupported AS_RS algorithm: %d\n", (int)key->as_rs_alg);
      break;
    };
  }
  return false;
#else
  OAUTH_ERROR("Oauth support not included");
  return false;
#endif
}

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

Coverage Report

Created: 2025-08-03 07:00