net/core/utils.c

   1 /*
   2  *      Generic address resultion entity
   3  *
   4  *      Authors:
   5  *      net_random Alan Cox
   6  *      net_ratelimit Andi Kleen
   7  *      in{4,6}_pton YOSHIFUJI Hideaki, Copyright (C)2006 USAGI/WIDE Project
   8  *
   9  *      Created by Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
  10  *
  11  *      This program is free software; you can redistribute it and/or
  12  *      modify it under the terms of the GNU General Public License
  13  *      as published by the Free Software Foundation; either version
  14  *      2 of the License, or (at your option) any later version.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/kernel.h>
  20 #include <linux/inet.h>
  21 #include <linux/mm.h>
  22 #include <linux/net.h>
  23 #include <linux/string.h>
  24 #include <linux/types.h>
  25 #include <linux/random.h>
  26 #include <linux/percpu.h>
  27 #include <linux/init.h>
  28
  29 #include <asm/byteorder.h>
  30 #include <asm/system.h>
  31 #include <asm/uaccess.h>
  32
  33 int net_msg_cost = 5*HZ;
  34 int net_msg_burst = 10;
  35
  36 /*
  37  * All net warning printk()s should be guarded by this function.
  38  */
  39 int net_ratelimit(void)
  40 {
  41         return __printk_ratelimit(net_msg_cost, net_msg_burst);
  42 }
  43 EXPORT_SYMBOL(net_ratelimit);
  44
  45 /*
  46  * Convert an ASCII string to binary IP.
  47  * This is outside of net/ipv4/ because various code that uses IP addresses
  48  * is otherwise not dependent on the TCP/IP stack.
  49  */
  50
  51 __be32 in_aton(const char *str)
  52 {
  53         unsigned long l;
  54         unsigned int val;
  55         int i;
  56
  57         l = 0;
  58         for (i = 0; i < 4; i++)
  59         {
  60                 l <<= 8;
  61                 if (*str != '\0')
  62                 {
  63                         val = 0;
  64                         while (*str != '\0' && *str != '.' && *str != '\n')
  65                         {
  66                                 val *= 10;
  67                                 val += *str - '0';
  68                                 str++;
  69                         }
  70                         l |= val;
  71                         if (*str != '\0')
  72                                 str++;
  73                 }
  74         }
  75         return(htonl(l));
  76 }
  77
  78 EXPORT_SYMBOL(in_aton);
  79
  80 #define IN6PTON_XDIGIT          0x00010000
  81 #define IN6PTON_DIGIT           0x00020000
  82 #define IN6PTON_COLON_MASK      0x00700000
  83 #define IN6PTON_COLON_1         0x00100000      /* single : requested */
  84 #define IN6PTON_COLON_2         0x00200000      /* second : requested */
  85 #define IN6PTON_COLON_1_2       0x00400000      /* :: requested */
  86 #define IN6PTON_DOT             0x00800000      /* . */
  87 #define IN6PTON_DELIM           0x10000000
  88 #define IN6PTON_NULL            0x20000000      /* first/tail */
  89 #define IN6PTON_UNKNOWN         0x40000000
  90
  91 static inline int digit2bin(char c, int delim)
  92 {
  93         if (c == delim || c == '\0')
  94                 return IN6PTON_DELIM;
  95         if (c == '.')
  96                 return IN6PTON_DOT;
  97         if (c >= '0' && c <= '9')
  98                 return (IN6PTON_DIGIT | (c - '0'));
  99         return IN6PTON_UNKNOWN;
 100 }
 101
 102 static inline int xdigit2bin(char c, int delim)
 103 {
 104         if (c == delim || c == '\0')
 105                 return IN6PTON_DELIM;
 106         if (c == ':')
 107                 return IN6PTON_COLON_MASK;
 108         if (c == '.')
 109                 return IN6PTON_DOT;
 110         if (c >= '0' && c <= '9')
 111                 return (IN6PTON_XDIGIT | IN6PTON_DIGIT| (c - '0'));
 112         if (c >= 'a' && c <= 'f')
 113                 return (IN6PTON_XDIGIT | (c - 'a' + 10));
 114         if (c >= 'A' && c <= 'F')
 115                 return (IN6PTON_XDIGIT | (c - 'A' + 10));
 116         if (delim == -1)
 117                 return IN6PTON_DELIM;
 118         return IN6PTON_UNKNOWN;
 119 }
 120
 121 int in4_pton(const char *src, int srclen,
 122              u8 *dst,
 123              int delim, const char **end)
 124 {
 125         const char *s;
 126         u8 *d;
 127         u8 dbuf[4];
 128         int ret = 0;
 129         int i;
 130         int w = 0;
 131
 132         if (srclen < 0)
 133                 srclen = strlen(src);
 134         s = src;
 135         d = dbuf;
 136         i = 0;
 137         while(1) {
 138                 int c;
 139                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 140                 if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM))) {
 141                         goto out;
 142                 }
 143                 if (c & (IN6PTON_DOT | IN6PTON_DELIM)) {
 144                         if (w == 0)
 145                                 goto out;
 146                         *d++ = w & 0xff;
 147                         w = 0;
 148                         i++;
 149                         if (c & IN6PTON_DELIM) {
 150                                 if (i != 4)
 151                                         goto out;
 152                                 break;
 153                         }
 154                         goto cont;
 155                 }
 156                 w = (w * 10) + c;
 157                 if ((w & 0xffff) > 255) {
 158                         goto out;
 159                 }
 160 cont:
 161                 if (i >= 4)
 162                         goto out;
 163                 s++;
 164                 srclen--;
 165         }
 166         ret = 1;
 167         memcpy(dst, dbuf, sizeof(dbuf));
 168 out:
 169         if (end)
 170                 *end = s;
 171         return ret;
 172 }
 173
 174 EXPORT_SYMBOL(in4_pton);
 175
 176 int in6_pton(const char *src, int srclen,
 177              u8 *dst,
 178              int delim, const char **end)
 179 {
 180         const char *s, *tok = NULL;
 181         u8 *d, *dc = NULL;
 182         u8 dbuf[16];
 183         int ret = 0;
 184         int i;
 185         int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
 186         int w = 0;
 187
 188         memset(dbuf, 0, sizeof(dbuf));
 189
 190         s = src;
 191         d = dbuf;
 192         if (srclen < 0)
 193                 srclen = strlen(src);
 194
 195         while (1) {
 196                 int c;
 197
 198                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 199                 if (!(c & state))
 200                         goto out;
 201                 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 202                         /* process one 16-bit word */
 203                         if (!(state & IN6PTON_NULL)) {
 204                                 *d++ = (w >> 8) & 0xff;
 205                                 *d++ = w & 0xff;
 206                         }
 207                         w = 0;
 208                         if (c & IN6PTON_DELIM) {
 209                                 /* We've processed last word */
 210                                 break;
 211                         }
 212                         /*
 213                          * COLON_1 => XDIGIT
 214                          * COLON_2 => XDIGIT|DELIM
 215                          * COLON_1_2 => COLON_2
 216                          */
 217                         switch (state & IN6PTON_COLON_MASK) {
 218                         case IN6PTON_COLON_2:
 219                                 dc = d;
 220                                 state = IN6PTON_XDIGIT | IN6PTON_DELIM;
 221                                 if (dc - dbuf >= sizeof(dbuf))
 222                                         state |= IN6PTON_NULL;
 223                                 break;
 224                         case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
 225                                 state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
 226                                 break;
 227                         case IN6PTON_COLON_1:
 228                                 state = IN6PTON_XDIGIT;
 229                                 break;
 230                         case IN6PTON_COLON_1_2:
 231                                 state = IN6PTON_COLON_2;
 232                                 break;
 233                         default:
 234                                 state = 0;
 235                         }
 236                         tok = s + 1;
 237                         goto cont;
 238                 }
 239
 240                 if (c & IN6PTON_DOT) {
 241                         ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
 242                         if (ret > 0) {
 243                                 d += 4;
 244                                 break;
 245                         }
 246                         goto out;
 247                 }
 248
 249                 w = (w << 4) | (0xff & c);
 250                 state = IN6PTON_COLON_1 | IN6PTON_DELIM;
 251                 if (!(w & 0xf000)) {
 252                         state |= IN6PTON_XDIGIT;
 253                 }
 254                 if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
 255                         state |= IN6PTON_COLON_1_2;
 256                         state &= ~IN6PTON_DELIM;
 257                 }
 258                 if (d + 2 >= dbuf + sizeof(dbuf)) {
 259                         state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
 260                 }
 261 cont:
 262                 if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
 263                     d + 4 == dbuf + sizeof(dbuf)) {
 264                         state |= IN6PTON_DOT;
 265                 }
 266                 if (d >= dbuf + sizeof(dbuf)) {
 267                         state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
 268                 }
 269                 s++;
 270                 srclen--;
 271         }
 272
 273         i = 15; d--;
 274
 275         if (dc) {
 276                 while(d >= dc)
 277                         dst[i--] = *d--;
 278                 while(i >= dc - dbuf)
 279                         dst[i--] = 0;
 280                 while(i >= 0)
 281                         dst[i--] = *d--;
 282         } else
 283                 memcpy(dst, dbuf, sizeof(dbuf));
 284
 285         ret = 1;
 286 out:
 287         if (end)
 288                 *end = s;
 289         return ret;
 290 }
 291
 292 EXPORT_SYMBOL(in6_pton);