Line data    Source code

       1             : /* uuid.c
       2             :  * strophe XMPP client library -- UUID generation
       3             :  *
       4             :  * Copyright (C) 2015 Dmitry Podgorny <pasis.ua@gmail.com>
       5             :  *
       6             :  *  This software is provided AS-IS with no warranty, either express
       7             :  *  or implied.
       8             :  *
       9             :  *  This program is dual licensed under the MIT and GPLv3 licenses.
      10             :  */
      11             : 
      12             : /** @file
      13             :  *  Generation of UUID version 4 according to RFC4122.
      14             :  */
      15             : 
      16             : #include "strophe.h"
      17             : #include "common.h"
      18             : 
      19             : /** @def XMPP_UUID_LEN
      20             :  *  UUID length in string representation excluding '\0'.
      21             :  */
      22             : #define XMPP_UUID_LEN 36
      23             : 
      24             : /** Generate UUID version 4 in pre-allocated buffer.
      25             :  *
      26             :  *  @param ctx a Strophe context object
      27             :  *  @param uuid pre-allocated buffer of size (XMPP_UUID_LEN + 1)
      28             :  */
      29           0 : static void crypto_uuid_gen(xmpp_ctx_t *ctx, char *uuid)
      30             : {
      31           0 :     unsigned char buf[16];
      32           0 :     int i = 0; /* uuid iterator */
      33           0 :     int j = 0; /* buf iterator */
      34             : 
      35           0 :     static const char hex[] = {'0', '1', '2', '3', '4', '5', '6', '7',
      36             :                                '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
      37             : 
      38           0 :     xmpp_rand_bytes(ctx->rand, buf, sizeof(buf));
      39           0 :     buf[8] &= 0x3f;
      40           0 :     buf[8] |= 0x80;
      41           0 :     buf[6] &= 0x0f;
      42           0 :     buf[6] |= 0x40;
      43           0 :     while (i < XMPP_UUID_LEN) {
      44           0 :         if (i == 8 || i == 13 || i == 18 || i == 23)
      45           0 :             uuid[i++] = '-';
      46             :         else {
      47           0 :             uuid[i++] = hex[buf[j] >> 4];
      48           0 :             uuid[i++] = hex[buf[j] & 0x0f];
      49           0 :             ++j;
      50             :         }
      51             :     }
      52           0 :     uuid[XMPP_UUID_LEN] = '\0';
      53           0 : }
      54             : 
      55             : /** Generate UUID version 4.
      56             :  *  This function allocates memory for the resulting string and must be freed
      57             :  *  with xmpp_free().
      58             :  *
      59             :  *  @param ctx a Strophe context object
      60             :  *
      61             :  *  @return ASCIIZ string
      62             :  */
      63           0 : char *xmpp_uuid_gen(xmpp_ctx_t *ctx)
      64             : {
      65           0 :     char *uuid;
      66             : 
      67           0 :     uuid = strophe_alloc(ctx, XMPP_UUID_LEN + 1);
      68           0 :     if (uuid != NULL) {
      69           0 :         crypto_uuid_gen(ctx, uuid);
      70             :     }
      71           0 :     return uuid;
      72             : }