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 __read_mostly = 5*HZ;
  34 int net_msg_burst __read_mostly = 10;
  35 int net_msg_warn __read_mostly = 1;
  36 EXPORT_SYMBOL(net_msg_warn);
  37
  38 /*
  39  * All net warning printk()s should be guarded by this function.
  40  */
  41 int net_ratelimit(void)
  42 {
  43         return __printk_ratelimit(net_msg_cost, net_msg_burst);
  44 }
  45 EXPORT_SYMBOL(net_ratelimit);
  46
  47 /*
  48  * Convert an ASCII string to binary IP.
  49  * This is outside of net/ipv4/ because various code that uses IP addresses
  50  * is otherwise not dependent on the TCP/IP stack.
  51  */
  52
  53 __be32 in_aton(const char *str)
  54 {
  55         unsigned long l;
  56         unsigned int val;
  57         int i;
  58
  59         l = 0;
  60         for (i = 0; i < 4; i++)
  61         {
  62                 l <<= 8;
  63                 if (*str != '\0')
  64                 {
  65                         val = 0;
  66                         while (*str != '\0' && *str != '.' && *str != '\n')
  67                         {
  68                                 val *= 10;
  69                                 val += *str - '0';
  70                                 str++;
  71                         }
  72                         l |= val;
  73                         if (*str != '\0')
  74                                 str++;
  75                 }
  76         }
  77         return(htonl(l));
  78 }
  79
  80 EXPORT_SYMBOL(in_aton);
  81
  82 #define IN6PTON_XDIGIT          0x00010000
  83 #define IN6PTON_DIGIT           0x00020000
  84 #define IN6PTON_COLON_MASK      0x00700000
  85 #define IN6PTON_COLON_1         0x00100000      /* single : requested */
  86 #define IN6PTON_COLON_2         0x00200000      /* second : requested */
  87 #define IN6PTON_COLON_1_2       0x00400000      /* :: requested */
  88 #define IN6PTON_DOT             0x00800000      /* . */
  89 #define IN6PTON_DELIM           0x10000000
  90 #define IN6PTON_NULL            0x20000000      /* first/tail */
  91 #define IN6PTON_UNKNOWN         0x40000000
  92
  93 static inline int digit2bin(char c, int delim)
  94 {
  95         if (c == delim || c == '\0')
  96                 return IN6PTON_DELIM;
  97         if (c == '.')
  98                 return IN6PTON_DOT;
  99         if (c >= '0' && c <= '9')
 100                 return (IN6PTON_DIGIT | (c - '0'));
 101         return IN6PTON_UNKNOWN;
 102 }
 103
 104 static inline int xdigit2bin(char c, int delim)
 105 {
 106         if (c == delim || c == '\0')
 107                 return IN6PTON_DELIM;
 108         if (c == ':')
 109                 return IN6PTON_COLON_MASK;
 110         if (c == '.')
 111                 return IN6PTON_DOT;
 112         if (c >= '0' && c <= '9')
 113                 return (IN6PTON_XDIGIT | IN6PTON_DIGIT| (c - '0'));
 114         if (c >= 'a' && c <= 'f')
 115                 return (IN6PTON_XDIGIT | (c - 'a' + 10));
 116         if (c >= 'A' && c <= 'F')
 117                 return (IN6PTON_XDIGIT | (c - 'A' + 10));
 118         if (delim == -1)
 119                 return IN6PTON_DELIM;
 120         return IN6PTON_UNKNOWN;
 121 }
 122
 123 int in4_pton(const char *src, int srclen,
 124              u8 *dst,
 125              int delim, const char **end)
 126 {
 127         const char *s;
 128         u8 *d;
 129         u8 dbuf[4];
 130         int ret = 0;
 131         int i;
 132         int w = 0;
 133
 134         if (srclen < 0)
 135                 srclen = strlen(src);
 136         s = src;
 137         d = dbuf;
 138         i = 0;
 139         while(1) {
 140                 int c;
 141                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 142                 if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM))) {
 143                         goto out;
 144                 }
 145                 if (c & (IN6PTON_DOT | IN6PTON_DELIM)) {
 146                         if (w == 0)
 147                                 goto out;
 148                         *d++ = w & 0xff;
 149                         w = 0;
 150                         i++;
 151                         if (c & IN6PTON_DELIM) {
 152                                 if (i != 4)
 153                                         goto out;
 154                                 break;
 155                         }
 156                         goto cont;
 157                 }
 158                 w = (w * 10) + c;
 159                 if ((w & 0xffff) > 255) {
 160                         goto out;
 161                 }
 162 cont:
 163                 if (i >= 4)
 164                         goto out;
 165                 s++;
 166                 srclen--;
 167         }
 168         ret = 1;
 169         memcpy(dst, dbuf, sizeof(dbuf));
 170 out:
 171         if (end)
 172                 *end = s;
 173         return ret;
 174 }
 175
 176 EXPORT_SYMBOL(in4_pton);
 177
 178 int in6_pton(const char *src, int srclen,
 179              u8 *dst,
 180              int delim, const char **end)
 181 {
 182         const char *s, *tok = NULL;
 183         u8 *d, *dc = NULL;
 184         u8 dbuf[16];
 185         int ret = 0;
 186         int i;
 187         int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
 188         int w = 0;
 189
 190         memset(dbuf, 0, sizeof(dbuf));
 191
 192         s = src;
 193         d = dbuf;
 194         if (srclen < 0)
 195                 srclen = strlen(src);
 196
 197         while (1) {
 198                 int c;
 199
 200                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 201                 if (!(c & state))
 202                         goto out;
 203                 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 204                         /* process one 16-bit word */
 205                         if (!(state & IN6PTON_NULL)) {
 206                                 *d++ = (w >> 8) & 0xff;
 207                                 *d++ = w & 0xff;
 208                         }
 209                         w = 0;
 210                         if (c & IN6PTON_DELIM) {
 211                                 /* We've processed last word */
 212                                 break;
 213                         }
 214                         /*
 215                          * COLON_1 => XDIGIT
 216                          * COLON_2 => XDIGIT|DELIM
 217                          * COLON_1_2 => COLON_2
 218                          */
 219                         switch (state & IN6PTON_COLON_MASK) {
 220                         case IN6PTON_COLON_2:
 221                                 dc = d;
 222                                 state = IN6PTON_XDIGIT | IN6PTON_DELIM;
 223                                 if (dc - dbuf >= sizeof(dbuf))
 224                                         state |= IN6PTON_NULL;
 225                                 break;
 226                         case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
 227                                 state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
 228                                 break;
 229                         case IN6PTON_COLON_1:
 230                                 state = IN6PTON_XDIGIT;
 231                                 break;
 232                         case IN6PTON_COLON_1_2:
 233                                 state = IN6PTON_COLON_2;
 234                                 break;
 235                         default:
 236                                 state = 0;
 237                         }
 238                         tok = s + 1;
 239                         goto cont;
 240                 }
 241
 242                 if (c & IN6PTON_DOT) {
 243                         ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
 244                         if (ret > 0) {
 245                                 d += 4;
 246                                 break;
 247                         }
 248                         goto out;
 249                 }
 250
 251                 w = (w << 4) | (0xff & c);
 252                 state = IN6PTON_COLON_1 | IN6PTON_DELIM;
 253                 if (!(w & 0xf000)) {
 254                         state |= IN6PTON_XDIGIT;
 255                 }
 256                 if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
 257                         state |= IN6PTON_COLON_1_2;
 258                         state &= ~IN6PTON_DELIM;
 259                 }
 260                 if (d + 2 >= dbuf + sizeof(dbuf)) {
 261                         state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
 262                 }
 263 cont:
 264                 if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
 265                     d + 4 == dbuf + sizeof(dbuf)) {
 266                         state |= IN6PTON_DOT;
 267                 }
 268                 if (d >= dbuf + sizeof(dbuf)) {
 269                         state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
 270                 }
 271                 s++;
 272                 srclen--;
 273         }
 274
 275         i = 15; d--;
 276
 277         if (dc) {
 278                 while(d >= dc)
 279                         dst[i--] = *d--;
 280                 while(i >= dc - dbuf)
 281                         dst[i--] = 0;
 282                 while(i >= 0)
 283                         dst[i--] = *d--;
 284         } else
 285                 memcpy(dst, dbuf, sizeof(dbuf));
 286
 287         ret = 1;
 288 out:
 289         if (end)
 290                 *end = s;
 291         return ret;
 292 }
 293
 294 EXPORT_SYMBOL(in6_pton);