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 #include <net/sock.h>
  29
  30 #include <asm/byteorder.h>
  31 #include <asm/system.h>
  32 #include <asm/uaccess.h>
  33
  34 int net_msg_cost __read_mostly = 5*HZ;
  35 int net_msg_burst __read_mostly = 10;
  36 int net_msg_warn __read_mostly = 1;
  37 EXPORT_SYMBOL(net_msg_warn);
  38
  39 /*
  40  * All net warning printk()s should be guarded by this function.
  41  */
  42 int net_ratelimit(void)
  43 {
  44         return __printk_ratelimit(net_msg_cost, net_msg_burst);
  45 }
  46 EXPORT_SYMBOL(net_ratelimit);
  47
  48 /*
  49  * Convert an ASCII string to binary IP.
  50  * This is outside of net/ipv4/ because various code that uses IP addresses
  51  * is otherwise not dependent on the TCP/IP stack.
  52  */
  53
  54 __be32 in_aton(const char *str)
  55 {
  56         unsigned long l;
  57         unsigned int val;
  58         int i;
  59
  60         l = 0;
  61         for (i = 0; i < 4; i++)
  62         {
  63                 l <<= 8;
  64                 if (*str != '\0')
  65                 {
  66                         val = 0;
  67                         while (*str != '\0' && *str != '.' && *str != '\n')
  68                         {
  69                                 val *= 10;
  70                                 val += *str - '0';
  71                                 str++;
  72                         }
  73                         l |= val;
  74                         if (*str != '\0')
  75                                 str++;
  76                 }
  77         }
  78         return(htonl(l));
  79 }
  80
  81 EXPORT_SYMBOL(in_aton);
  82
  83 #define IN6PTON_XDIGIT          0x00010000
  84 #define IN6PTON_DIGIT           0x00020000
  85 #define IN6PTON_COLON_MASK      0x00700000
  86 #define IN6PTON_COLON_1         0x00100000      /* single : requested */
  87 #define IN6PTON_COLON_2         0x00200000      /* second : requested */
  88 #define IN6PTON_COLON_1_2       0x00400000      /* :: requested */
  89 #define IN6PTON_DOT             0x00800000      /* . */
  90 #define IN6PTON_DELIM           0x10000000
  91 #define IN6PTON_NULL            0x20000000      /* first/tail */
  92 #define IN6PTON_UNKNOWN         0x40000000
  93
  94 static inline int digit2bin(char c, int delim)
  95 {
  96         if (c == delim || c == '\0')
  97                 return IN6PTON_DELIM;
  98         if (c == '.')
  99                 return IN6PTON_DOT;
 100         if (c >= '0' && c <= '9')
 101                 return (IN6PTON_DIGIT | (c - '0'));
 102         return IN6PTON_UNKNOWN;
 103 }
 104
 105 static inline int xdigit2bin(char c, int delim)
 106 {
 107         if (c == delim || c == '\0')
 108                 return IN6PTON_DELIM;
 109         if (c == ':')
 110                 return IN6PTON_COLON_MASK;
 111         if (c == '.')
 112                 return IN6PTON_DOT;
 113         if (c >= '0' && c <= '9')
 114                 return (IN6PTON_XDIGIT | IN6PTON_DIGIT| (c - '0'));
 115         if (c >= 'a' && c <= 'f')
 116                 return (IN6PTON_XDIGIT | (c - 'a' + 10));
 117         if (c >= 'A' && c <= 'F')
 118                 return (IN6PTON_XDIGIT | (c - 'A' + 10));
 119         if (delim == -1)
 120                 return IN6PTON_DELIM;
 121         return IN6PTON_UNKNOWN;
 122 }
 123
 124 int in4_pton(const char *src, int srclen,
 125              u8 *dst,
 126              int delim, const char **end)
 127 {
 128         const char *s;
 129         u8 *d;
 130         u8 dbuf[4];
 131         int ret = 0;
 132         int i;
 133         int w = 0;
 134
 135         if (srclen < 0)
 136                 srclen = strlen(src);
 137         s = src;
 138         d = dbuf;
 139         i = 0;
 140         while(1) {
 141                 int c;
 142                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 143                 if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
 144                         goto out;
 145                 }
 146                 if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 147                         if (w == 0)
 148                                 goto out;
 149                         *d++ = w & 0xff;
 150                         w = 0;
 151                         i++;
 152                         if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 153                                 if (i != 4)
 154                                         goto out;
 155                                 break;
 156                         }
 157                         goto cont;
 158                 }
 159                 w = (w * 10) + c;
 160                 if ((w & 0xffff) > 255) {
 161                         goto out;
 162                 }
 163 cont:
 164                 if (i >= 4)
 165                         goto out;
 166                 s++;
 167                 srclen--;
 168         }
 169         ret = 1;
 170         memcpy(dst, dbuf, sizeof(dbuf));
 171 out:
 172         if (end)
 173                 *end = s;
 174         return ret;
 175 }
 176
 177 EXPORT_SYMBOL(in4_pton);
 178
 179 int in6_pton(const char *src, int srclen,
 180              u8 *dst,
 181              int delim, const char **end)
 182 {
 183         const char *s, *tok = NULL;
 184         u8 *d, *dc = NULL;
 185         u8 dbuf[16];
 186         int ret = 0;
 187         int i;
 188         int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
 189         int w = 0;
 190
 191         memset(dbuf, 0, sizeof(dbuf));
 192
 193         s = src;
 194         d = dbuf;
 195         if (srclen < 0)
 196                 srclen = strlen(src);
 197
 198         while (1) {
 199                 int c;
 200
 201                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 202                 if (!(c & state))
 203                         goto out;
 204                 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 205                         /* process one 16-bit word */
 206                         if (!(state & IN6PTON_NULL)) {
 207                                 *d++ = (w >> 8) & 0xff;
 208                                 *d++ = w & 0xff;
 209                         }
 210                         w = 0;
 211                         if (c & IN6PTON_DELIM) {
 212                                 /* We've processed last word */
 213                                 break;
 214                         }
 215                         /*
 216                          * COLON_1 => XDIGIT
 217                          * COLON_2 => XDIGIT|DELIM
 218                          * COLON_1_2 => COLON_2
 219                          */
 220                         switch (state & IN6PTON_COLON_MASK) {
 221                         case IN6PTON_COLON_2:
 222                                 dc = d;
 223                                 state = IN6PTON_XDIGIT | IN6PTON_DELIM;
 224                                 if (dc - dbuf >= sizeof(dbuf))
 225                                         state |= IN6PTON_NULL;
 226                                 break;
 227                         case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
 228                                 state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
 229                                 break;
 230                         case IN6PTON_COLON_1:
 231                                 state = IN6PTON_XDIGIT;
 232                                 break;
 233                         case IN6PTON_COLON_1_2:
 234                                 state = IN6PTON_COLON_2;
 235                                 break;
 236                         default:
 237                                 state = 0;
 238                         }
 239                         tok = s + 1;
 240                         goto cont;
 241                 }
 242
 243                 if (c & IN6PTON_DOT) {
 244                         ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
 245                         if (ret > 0) {
 246                                 d += 4;
 247                                 break;
 248                         }
 249                         goto out;
 250                 }
 251
 252                 w = (w << 4) | (0xff & c);
 253                 state = IN6PTON_COLON_1 | IN6PTON_DELIM;
 254                 if (!(w & 0xf000)) {
 255                         state |= IN6PTON_XDIGIT;
 256                 }
 257                 if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
 258                         state |= IN6PTON_COLON_1_2;
 259                         state &= ~IN6PTON_DELIM;
 260                 }
 261                 if (d + 2 >= dbuf + sizeof(dbuf)) {
 262                         state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
 263                 }
 264 cont:
 265                 if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
 266                     d + 4 == dbuf + sizeof(dbuf)) {
 267                         state |= IN6PTON_DOT;
 268                 }
 269                 if (d >= dbuf + sizeof(dbuf)) {
 270                         state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
 271                 }
 272                 s++;
 273                 srclen--;
 274         }
 275
 276         i = 15; d--;
 277
 278         if (dc) {
 279                 while(d >= dc)
 280                         dst[i--] = *d--;
 281                 while(i >= dc - dbuf)
 282                         dst[i--] = 0;
 283                 while(i >= 0)
 284                         dst[i--] = *d--;
 285         } else
 286                 memcpy(dst, dbuf, sizeof(dbuf));
 287
 288         ret = 1;
 289 out:
 290         if (end)
 291                 *end = s;
 292         return ret;
 293 }
 294
 295 EXPORT_SYMBOL(in6_pton);