/*
    * uclient - ustream based protocol client library
    *
    * Copyright (C) 2014 Felix Fietkau <nbd@openwrt.org>
    *
    * Permission to use, copy, modify, and/or distribute this software for any
    * purpose with or without fee is hereby granted, provided that the above
    * copyright notice and this permission notice appear in all copies.
    *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  #include <stdint.h>
  #include <stdlib.h>
  #include <string.h>
  #include <ctype.h>
  
  #include <libubox/md5.h>
  #include <libubox/utils.h>
  
  #include "uclient-utils.h"
  
  static const char *b64 =
  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  
  void base64_encode(const void *inbuf, unsigned int len, void *outbuf)
  {
          unsigned char *out = outbuf;
          const uint8_t *in = inbuf;
          unsigned int i;
          int pad = len % 3;
  
          for (i = 0; i < len - pad; i += 3) {
                  uint32_t in3 = (in[0] << 16) | (in[1] << 8) | in[2];
                  int k;
  
                  for (k = 3; k >= 0; k--) {
                          out[k] = b64[in3 & 0x3f];
                          in3 >>= 6;
                  }
                  in += 3;
                  out += 4;
          }
  
          if (pad) {
                  uint32_t in2 = in[0] << (16 - 6);
  
                  out[3] = '=';
  
                  if (pad > 1) {
                          in2 |= in[1] << (8 - 6);
                          out[2] = b64[in2 & 0x3f];
                  } else {
                          out[2] = '=';
                  }
  
                  in2 >>= 6;
                  out[1] = b64[in2 & 0x3f];
                  in2 >>= 6;
                  out[0] = b64[in2 & 0x3f];
  
                  out += 4;
          }
  
          *out = '\0';
  }
  
  int uclient_urldecode(const char *in, char *out, bool decode_plus)
  {
          static char dec[3];
          int ret = 0;
          char c;
  
          while ((c = *(in++))) {
                  if (c == '%') {
                          if (!isxdigit(in[0]) || !isxdigit(in[1]))
                                  return -1;
  
                          dec[0] = in[0];
                          dec[1] = in[1];
                          c = strtol(dec, NULL, 16);
                          in += 2;
                  } else if (decode_plus && c == '+') {
                          c = ' ';
                  }
  
                  *(out++) = c;
                  ret++;
          }
  
          *out = 0;
          return ret;
  }
  
 static char hex_digit(char val)
 {
         val += val > 9 ? 'a' - 10 : '';
         return val;
 }
 
 void bin_to_hex(char *dest, const void *buf, int len)
 {
         const uint8_t *data = buf;
         int i;
 
         for (i = 0; i < len; i++) {
                 *(dest++) = hex_digit(data[i] >> 4);
                 *(dest++) = hex_digit(data[i] & 0xf);
         }
         *dest = 0;
 }
 
 static void http_create_hash(char *dest, const char * const * str, int n_str)
 {
         uint32_t hash[4];
         md5_ctx_t md5;
         int i;
 
         md5_begin(&md5);
         for (i = 0; i < n_str; i++) {
                 if (i)
                         md5_hash(":", 1, &md5);
                 md5_hash(str[i], strlen(str[i]), &md5);
         }
         md5_end(hash, &md5);
         bin_to_hex(dest, &hash, sizeof(hash));
 }
 
 void http_digest_calculate_auth_hash(char *dest, const char *user, const char *realm, const char *password)
 {
         const char *hash_str[] = {
                 user,
                 realm,
                 password
         };
 
         http_create_hash(dest, hash_str, ARRAY_SIZE(hash_str));
 }
 
 void http_digest_calculate_response(char *dest, const struct http_digest_data *data)
 {
         const char *h_a2_strings[] = {
                 data->method,
                 data->uri,
         };
         const char *resp_strings[] = {
                 data->auth_hash,
                 data->nonce,
                 data->nc,
                 data->cnonce,
                 data->qop,
                 dest, /* initialized to H(A2) first */
         };
 
         http_create_hash(dest, h_a2_strings, ARRAY_SIZE(h_a2_strings));
         http_create_hash(dest, resp_strings, ARRAY_SIZE(resp_strings));
 }
 
 char *uclient_get_url_filename(const char *url, const char *default_name)
 {
         const char *str;
         int len = strcspn(url, ";&");
 
         while (len > 0 && url[len - 1] == '/')
                 len--;
 
         for (str = url + len - 1; str >= url; str--) {
                 if (*str == '/')
                         break;
         }
 
         str++;
         len -= str - url;
 
         if (len > 0)
                 return strndup(str, len);
 
         return strdup(default_name);
 }
 

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