1 /* 2 * Copyright (c) 2004 Kungliga Tekniska Högskolan 3 * (Royal Institute of Technology, Stockholm, Sweden). 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * 3. Neither the name of the Institute nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifdef HAVE_CONFIG_H 35 #include <config.h> 36 #endif 37 #include <string.h> 38 #include "windlocl.h" 39 40 static const unsigned base = 36; 41 static const unsigned t_min = 1; 42 static const unsigned t_max = 26; 43 static const unsigned skew = 38; 44 static const unsigned damp = 700; 45 static const unsigned initial_n = 128; 46 static const unsigned initial_bias = 72; 47 48 static unsigned 49 digit(unsigned n) 50 { 51 return "abcdefghijklmnopqrstuvwxyz0123456789"[n]; 52 } 53 54 static unsigned 55 adapt(unsigned delta, unsigned numpoints, int first) 56 { 57 unsigned k; 58 59 if (first) 60 delta = delta / damp; 61 else 62 delta /= 2; 63 delta += delta / numpoints; 64 k = 0; 65 while (delta > ((base - t_min) * t_max) / 2) { 66 delta /= base - t_min; 67 k += base; 68 } 69 return k + (((base - t_min + 1) * delta) / (delta + skew)); 70 } 71 72 /** 73 * Convert an UCS4 string to a puny-coded DNS label string suitable 74 * when combined with delimiters and other labels for DNS lookup. 75 * 76 * @param in an UCS4 string to convert 77 * @param in_len the length of in. 78 * @param out the resulting puny-coded string. The string is not NUL 79 * terminatied. 80 * @param out_len before processing out_len should be the length of 81 * the out variable, after processing it will be the length of the out 82 * string. 83 * 84 * @return returns 0 on success, an wind error code otherwise 85 * @ingroup wind 86 */ 87 88 int 89 wind_punycode_label_toascii(const uint32_t *in, size_t in_len, 90 char *out, size_t *out_len) 91 { 92 unsigned n = initial_n; 93 unsigned delta = 0; 94 unsigned bias = initial_bias; 95 unsigned h = 0; 96 unsigned b; 97 unsigned i; 98 unsigned o = 0; 99 unsigned m; 100 101 for (i = 0; i < in_len; ++i) { 102 if (in[i] < 0x80) { 103 ++h; 104 if (o >= *out_len) 105 return WIND_ERR_OVERRUN; 106 out[o++] = in[i]; 107 } 108 } 109 b = h; 110 if (b > 0) { 111 if (o >= *out_len) 112 return WIND_ERR_OVERRUN; 113 out[o++] = 0x2D; 114 } 115 /* is this string punycoded */ 116 if (h < in_len) { 117 if (o + 4 >= *out_len) 118 return WIND_ERR_OVERRUN; 119 memmove(out + 4, out, o); 120 memcpy(out, "xn--", 4); 121 o += 4; 122 } 123 124 while (h < in_len) { 125 m = (unsigned)-1; 126 for (i = 0; i < in_len; ++i) 127 if(in[i] < m && in[i] >= n) 128 m = in[i]; 129 130 delta += (m - n) * (h + 1); 131 n = m; 132 for (i = 0; i < in_len; ++i) { 133 if (in[i] < n) { 134 ++delta; 135 } else if (in[i] == n) { 136 unsigned q = delta; 137 unsigned k; 138 for (k = base; ; k += base) { 139 unsigned t; 140 if (k <= bias) 141 t = t_min; 142 else if (k >= bias + t_max) 143 t = t_max; 144 else 145 t = k - bias; 146 if (q < t) 147 break; 148 if (o >= *out_len) 149 return WIND_ERR_OVERRUN; 150 out[o++] = digit(t + ((q - t) % (base - t))); 151 q = (q - t) / (base - t); 152 } 153 if (o >= *out_len) 154 return WIND_ERR_OVERRUN; 155 out[o++] = digit(q); 156 /* output */ 157 bias = adapt(delta, h + 1, h == b); 158 delta = 0; 159 ++h; 160 } 161 } 162 ++delta; 163 ++n; 164 } 165 166 *out_len = o; 167 return 0; 168 } 169