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/percpu.h>
  26 #include <linux/init.h>
  27 #include <linux/ratelimit.h>
  28
  29 #include <net/sock.h>
  30 #include <net/net_ratelimit.h>
  31
  32 #include <asm/byteorder.h>
  33 #include <asm/system.h>
  34 #include <asm/uaccess.h>
  35
  36 int net_msg_warn __read_mostly = 1;
  37 EXPORT_SYMBOL(net_msg_warn);
  38
  39 DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
  40 /*
  41  * All net warning printk()s should be guarded by this function.
  42  */
  43 int net_ratelimit(void)
  44 {
  45         return __ratelimit(&net_ratelimit_state);
  46 }
  47 EXPORT_SYMBOL(net_ratelimit);
  48
  49 /*
  50  * Convert an ASCII string to binary IP.
  51  * This is outside of net/ipv4/ because various code that uses IP addresses
  52  * is otherwise not dependent on the TCP/IP stack.
  53  */
  54
  55 __be32 in_aton(const char *str)
  56 {
  57         unsigned long l;
  58         unsigned int val;
  59         int i;
  60
  61         l = 0;
  62         for (i = 0; i < 4; i++)
  63         {
  64                 l <<= 8;
  65                 if (*str != '\0')
  66                 {
  67                         val = 0;
  68                         while (*str != '\0' && *str != '.' && *str != '\n')
  69                         {
  70                                 val *= 10;
  71                                 val += *str - '0';
  72                                 str++;
  73                         }
  74                         l |= val;
  75                         if (*str != '\0')
  76                                 str++;
  77                 }
  78         }
  79         return htonl(l);
  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 xdigit2bin(char c, int delim)
  95 {
  96         int val;
  97
  98         if (c == delim || c == '\0')
  99                 return IN6PTON_DELIM;
 100         if (c == ':')
 101                 return IN6PTON_COLON_MASK;
 102         if (c == '.')
 103                 return IN6PTON_DOT;
 104
 105         val = hex_to_bin(c);
 106         if (val >= 0)
 107                 return val | IN6PTON_XDIGIT | (val < 10 ? IN6PTON_DIGIT : 0);
 108
 109         if (delim == -1)
 110                 return IN6PTON_DELIM;
 111         return IN6PTON_UNKNOWN;
 112 }
 113
 114 int in4_pton(const char *src, int srclen,
 115              u8 *dst,
 116              int delim, const char **end)
 117 {
 118         const char *s;
 119         u8 *d;
 120         u8 dbuf[4];
 121         int ret = 0;
 122         int i;
 123         int w = 0;
 124
 125         if (srclen < 0)
 126                 srclen = strlen(src);
 127         s = src;
 128         d = dbuf;
 129         i = 0;
 130         while(1) {
 131                 int c;
 132                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 133                 if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
 134                         goto out;
 135                 }
 136                 if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 137                         if (w == 0)
 138                                 goto out;
 139                         *d++ = w & 0xff;
 140                         w = 0;
 141                         i++;
 142                         if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 143                                 if (i != 4)
 144                                         goto out;
 145                                 break;
 146                         }
 147                         goto cont;
 148                 }
 149                 w = (w * 10) + c;
 150                 if ((w & 0xffff) > 255) {
 151                         goto out;
 152                 }
 153 cont:
 154                 if (i >= 4)
 155                         goto out;
 156                 s++;
 157                 srclen--;
 158         }
 159         ret = 1;
 160         memcpy(dst, dbuf, sizeof(dbuf));
 161 out:
 162         if (end)
 163                 *end = s;
 164         return ret;
 165 }
 166 EXPORT_SYMBOL(in4_pton);
 167
 168 int in6_pton(const char *src, int srclen,
 169              u8 *dst,
 170              int delim, const char **end)
 171 {
 172         const char *s, *tok = NULL;
 173         u8 *d, *dc = NULL;
 174         u8 dbuf[16];
 175         int ret = 0;
 176         int i;
 177         int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
 178         int w = 0;
 179
 180         memset(dbuf, 0, sizeof(dbuf));
 181
 182         s = src;
 183         d = dbuf;
 184         if (srclen < 0)
 185                 srclen = strlen(src);
 186
 187         while (1) {
 188                 int c;
 189
 190                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 191                 if (!(c & state))
 192                         goto out;
 193                 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 194                         /* process one 16-bit word */
 195                         if (!(state & IN6PTON_NULL)) {
 196                                 *d++ = (w >> 8) & 0xff;
 197                                 *d++ = w & 0xff;
 198                         }
 199                         w = 0;
 200                         if (c & IN6PTON_DELIM) {
 201                                 /* We've processed last word */
 202                                 break;
 203                         }
 204                         /*
 205                          * COLON_1 => XDIGIT
 206                          * COLON_2 => XDIGIT|DELIM
 207                          * COLON_1_2 => COLON_2
 208                          */
 209                         switch (state & IN6PTON_COLON_MASK) {
 210                         case IN6PTON_COLON_2:
 211                                 dc = d;
 212                                 state = IN6PTON_XDIGIT | IN6PTON_DELIM;
 213                                 if (dc - dbuf >= sizeof(dbuf))
 214                                         state |= IN6PTON_NULL;
 215                                 break;
 216                         case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
 217                                 state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
 218                                 break;
 219                         case IN6PTON_COLON_1:
 220                                 state = IN6PTON_XDIGIT;
 221                                 break;
 222                         case IN6PTON_COLON_1_2:
 223                                 state = IN6PTON_COLON_2;
 224                                 break;
 225                         default:
 226                                 state = 0;
 227                         }
 228                         tok = s + 1;
 229                         goto cont;
 230                 }
 231
 232                 if (c & IN6PTON_DOT) {
 233                         ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
 234                         if (ret > 0) {
 235                                 d += 4;
 236                                 break;
 237                         }
 238                         goto out;
 239                 }
 240
 241                 w = (w << 4) | (0xff & c);
 242                 state = IN6PTON_COLON_1 | IN6PTON_DELIM;
 243                 if (!(w & 0xf000)) {
 244                         state |= IN6PTON_XDIGIT;
 245                 }
 246                 if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
 247                         state |= IN6PTON_COLON_1_2;
 248                         state &= ~IN6PTON_DELIM;
 249                 }
 250                 if (d + 2 >= dbuf + sizeof(dbuf)) {
 251                         state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
 252                 }
 253 cont:
 254                 if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
 255                     d + 4 == dbuf + sizeof(dbuf)) {
 256                         state |= IN6PTON_DOT;
 257                 }
 258                 if (d >= dbuf + sizeof(dbuf)) {
 259                         state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
 260                 }
 261                 s++;
 262                 srclen--;
 263         }
 264
 265         i = 15; d--;
 266
 267         if (dc) {
 268                 while(d >= dc)
 269                         dst[i--] = *d--;
 270                 while(i >= dc - dbuf)
 271                         dst[i--] = 0;
 272                 while(i >= 0)
 273                         dst[i--] = *d--;
 274         } else
 275                 memcpy(dst, dbuf, sizeof(dbuf));
 276
 277         ret = 1;
 278 out:
 279         if (end)
 280                 *end = s;
 281         return ret;
 282 }
 283 EXPORT_SYMBOL(in6_pton);
 284
 285 void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
 286                               __be32 from, __be32 to, int pseudohdr)
 287 {
 288         __be32 diff[] = { ~from, to };
 289         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 290                 *sum = csum_fold(csum_partial(diff, sizeof(diff),
 291                                 ~csum_unfold(*sum)));
 292                 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
 293                         skb->csum = ~csum_partial(diff, sizeof(diff),
 294                                                 ~skb->csum);
 295         } else if (pseudohdr)
 296                 *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
 297                                 csum_unfold(*sum)));
 298 }
 299 EXPORT_SYMBOL(inet_proto_csum_replace4);
 300
 301 int mac_pton(const char *s, u8 *mac)
 302 {
 303         int i;
 304
 305         /* XX:XX:XX:XX:XX:XX */
 306         if (strlen(s) < 3 * ETH_ALEN - 1)
 307                 return 0;
 308
 309         /* Don't dirty result unless string is valid MAC. */
 310         for (i = 0; i < ETH_ALEN; i++) {
 311                 if (!strchr("0123456789abcdefABCDEF", s[i * 3]))
 312                         return 0;
 313                 if (!strchr("0123456789abcdefABCDEF", s[i * 3 + 1]))
 314                         return 0;
 315                 if (i != ETH_ALEN - 1 && s[i * 3 + 2] != ':')
 316                         return 0;
 317         }
 318         for (i = 0; i < ETH_ALEN; i++) {
 319                 mac[i] = (hex_to_bin(s[i * 3]) << 4) | hex_to_bin(s[i * 3 + 1]);
 320         }
 321         return 1;
 322 }
 323 EXPORT_SYMBOL(mac_pton);