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, char 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, char 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         return IN6PTON_UNKNOWN;
 117 }
 118
 119 int in4_pton(const char *src, int srclen,
 120              u8 *dst,
 121              char delim, const char **end)
 122 {
 123         const char *s;
 124         u8 *d;
 125         u8 dbuf[4];
 126         int ret = 0;
 127         int i;
 128         int w = 0;
 129
 130         if (srclen < 0)
 131                 srclen = strlen(src);
 132         s = src;
 133         d = dbuf;
 134         i = 0;
 135         while(1) {
 136                 int c;
 137                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 138                 if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM))) {
 139                         goto out;
 140                 }
 141                 if (c & (IN6PTON_DOT | IN6PTON_DELIM)) {
 142                         if (w == 0)
 143                                 goto out;
 144                         *d++ = w & 0xff;
 145                         w = 0;
 146                         i++;
 147                         if (c & IN6PTON_DELIM) {
 148                                 if (i != 4)
 149                                         goto out;
 150                                 break;
 151                         }
 152                         goto cont;
 153                 }
 154                 w = (w * 10) + c;
 155                 if ((w & 0xffff) > 255) {
 156                         goto out;
 157                 }
 158 cont:
 159                 if (i >= 4)
 160                         goto out;
 161                 s++;
 162                 srclen--;
 163         }
 164         ret = 1;
 165         memcpy(dst, dbuf, sizeof(dbuf));
 166 out:
 167         if (end)
 168                 *end = s;
 169         return ret;
 170 }
 171
 172 EXPORT_SYMBOL(in4_pton);
 173
 174 int in6_pton(const char *src, int srclen,
 175              u8 *dst,
 176              char delim, const char **end)
 177 {
 178         const char *s, *tok = NULL;
 179         u8 *d, *dc = NULL;
 180         u8 dbuf[16];
 181         int ret = 0;
 182         int i;
 183         int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
 184         int w = 0;
 185
 186         memset(dbuf, 0, sizeof(dbuf));
 187
 188         s = src;
 189         d = dbuf;
 190         if (srclen < 0)
 191                 srclen = strlen(src);
 192
 193         while (1) {
 194                 int c;
 195
 196                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 197                 if (!(c & state))
 198                         goto out;
 199                 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 200                         /* process one 16-bit word */
 201                         if (!(state & IN6PTON_NULL)) {
 202                                 *d++ = (w >> 8) & 0xff;
 203                                 *d++ = w & 0xff;
 204                         }
 205                         w = 0;
 206                         if (c & IN6PTON_DELIM) {
 207                                 /* We've processed last word */
 208                                 break;
 209                         }
 210                         /*
 211                          * COLON_1 => XDIGIT
 212                          * COLON_2 => XDIGIT|DELIM
 213                          * COLON_1_2 => COLON_2
 214                          */
 215                         switch (state & IN6PTON_COLON_MASK) {
 216                         case IN6PTON_COLON_2:
 217                                 dc = d;
 218                                 state = IN6PTON_XDIGIT | IN6PTON_DELIM;
 219                                 if (dc - dbuf >= sizeof(dbuf))
 220                                         state |= IN6PTON_NULL;
 221                                 break;
 222                         case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
 223                                 state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
 224                                 break;
 225                         case IN6PTON_COLON_1:
 226                                 state = IN6PTON_XDIGIT;
 227                                 break;
 228                         case IN6PTON_COLON_1_2:
 229                                 state = IN6PTON_COLON_2;
 230                                 break;
 231                         default:
 232                                 state = 0;
 233                         }
 234                         tok = s + 1;
 235                         goto cont;
 236                 }
 237
 238                 if (c & IN6PTON_DOT) {
 239                         ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
 240                         if (ret > 0) {
 241                                 d += 4;
 242                                 break;
 243                         }
 244                         goto out;
 245                 }
 246
 247                 w = (w << 4) | (0xff & c);
 248                 state = IN6PTON_COLON_1 | IN6PTON_DELIM;
 249                 if (!(w & 0xf000)) {
 250                         state |= IN6PTON_XDIGIT;
 251                 }
 252                 if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
 253                         state |= IN6PTON_COLON_1_2;
 254                         state &= ~IN6PTON_DELIM;
 255                 }
 256                 if (d + 2 >= dbuf + sizeof(dbuf)) {
 257                         state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
 258                 }
 259 cont:
 260                 if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
 261                     d + 4 == dbuf + sizeof(dbuf)) {
 262                         state |= IN6PTON_DOT;
 263                 }
 264                 if (d >= dbuf + sizeof(dbuf)) {
 265                         state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
 266                 }
 267                 s++;
 268                 srclen--;
 269         }
 270
 271         i = 15; d--;
 272
 273         if (dc) {
 274                 while(d >= dc)
 275                         dst[i--] = *d--;
 276                 while(i >= dc - dbuf)
 277                         dst[i--] = 0;
 278                 while(i >= 0)
 279                         dst[i--] = *d--;
 280         } else
 281                 memcpy(dst, dbuf, sizeof(dbuf));
 282
 283         ret = 1;
 284 out:
 285         if (end)
 286                 *end = s;
 287         return ret;
 288 }
 289
 290 EXPORT_SYMBOL(in6_pton);