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/uaccess.h>
  34
  35 int net_msg_warn __read_mostly = 1;
  36 EXPORT_SYMBOL(net_msg_warn);
  37
  38 DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
  39 /*
  40  * All net warning printk()s should be guarded by this function.
  41  */
  42 int net_ratelimit(void)
  43 {
  44         return __ratelimit(&net_ratelimit_state);
  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                 l <<= 8;
  63                 if (*str != '\0') {
  64                         val = 0;
  65                         while (*str != '\0' && *str != '.' && *str != '\n') {
  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 EXPORT_SYMBOL(in_aton);
  78
  79 #define IN6PTON_XDIGIT          0x00010000
  80 #define IN6PTON_DIGIT           0x00020000
  81 #define IN6PTON_COLON_MASK      0x00700000
  82 #define IN6PTON_COLON_1         0x00100000      /* single : requested */
  83 #define IN6PTON_COLON_2         0x00200000      /* second : requested */
  84 #define IN6PTON_COLON_1_2       0x00400000      /* :: requested */
  85 #define IN6PTON_DOT             0x00800000      /* . */
  86 #define IN6PTON_DELIM           0x10000000
  87 #define IN6PTON_NULL            0x20000000      /* first/tail */
  88 #define IN6PTON_UNKNOWN         0x40000000
  89
  90 static inline int xdigit2bin(char c, int delim)
  91 {
  92         int val;
  93
  94         if (c == delim || c == '\0')
  95                 return IN6PTON_DELIM;
  96         if (c == ':')
  97                 return IN6PTON_COLON_MASK;
  98         if (c == '.')
  99                 return IN6PTON_DOT;
 100
 101         val = hex_to_bin(c);
 102         if (val >= 0)
 103                 return val | IN6PTON_XDIGIT | (val < 10 ? IN6PTON_DIGIT : 0);
 104
 105         if (delim == -1)
 106                 return IN6PTON_DELIM;
 107         return IN6PTON_UNKNOWN;
 108 }
 109
 110 int in4_pton(const char *src, int srclen,
 111              u8 *dst,
 112              int delim, const char **end)
 113 {
 114         const char *s;
 115         u8 *d;
 116         u8 dbuf[4];
 117         int ret = 0;
 118         int i;
 119         int w = 0;
 120
 121         if (srclen < 0)
 122                 srclen = strlen(src);
 123         s = src;
 124         d = dbuf;
 125         i = 0;
 126         while(1) {
 127                 int c;
 128                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 129                 if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
 130                         goto out;
 131                 }
 132                 if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 133                         if (w == 0)
 134                                 goto out;
 135                         *d++ = w & 0xff;
 136                         w = 0;
 137                         i++;
 138                         if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 139                                 if (i != 4)
 140                                         goto out;
 141                                 break;
 142                         }
 143                         goto cont;
 144                 }
 145                 w = (w * 10) + c;
 146                 if ((w & 0xffff) > 255) {
 147                         goto out;
 148                 }
 149 cont:
 150                 if (i >= 4)
 151                         goto out;
 152                 s++;
 153                 srclen--;
 154         }
 155         ret = 1;
 156         memcpy(dst, dbuf, sizeof(dbuf));
 157 out:
 158         if (end)
 159                 *end = s;
 160         return ret;
 161 }
 162 EXPORT_SYMBOL(in4_pton);
 163
 164 int in6_pton(const char *src, int srclen,
 165              u8 *dst,
 166              int delim, const char **end)
 167 {
 168         const char *s, *tok = NULL;
 169         u8 *d, *dc = NULL;
 170         u8 dbuf[16];
 171         int ret = 0;
 172         int i;
 173         int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
 174         int w = 0;
 175
 176         memset(dbuf, 0, sizeof(dbuf));
 177
 178         s = src;
 179         d = dbuf;
 180         if (srclen < 0)
 181                 srclen = strlen(src);
 182
 183         while (1) {
 184                 int c;
 185
 186                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 187                 if (!(c & state))
 188                         goto out;
 189                 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 190                         /* process one 16-bit word */
 191                         if (!(state & IN6PTON_NULL)) {
 192                                 *d++ = (w >> 8) & 0xff;
 193                                 *d++ = w & 0xff;
 194                         }
 195                         w = 0;
 196                         if (c & IN6PTON_DELIM) {
 197                                 /* We've processed last word */
 198                                 break;
 199                         }
 200                         /*
 201                          * COLON_1 => XDIGIT
 202                          * COLON_2 => XDIGIT|DELIM
 203                          * COLON_1_2 => COLON_2
 204                          */
 205                         switch (state & IN6PTON_COLON_MASK) {
 206                         case IN6PTON_COLON_2:
 207                                 dc = d;
 208                                 state = IN6PTON_XDIGIT | IN6PTON_DELIM;
 209                                 if (dc - dbuf >= sizeof(dbuf))
 210                                         state |= IN6PTON_NULL;
 211                                 break;
 212                         case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
 213                                 state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
 214                                 break;
 215                         case IN6PTON_COLON_1:
 216                                 state = IN6PTON_XDIGIT;
 217                                 break;
 218                         case IN6PTON_COLON_1_2:
 219                                 state = IN6PTON_COLON_2;
 220                                 break;
 221                         default:
 222                                 state = 0;
 223                         }
 224                         tok = s + 1;
 225                         goto cont;
 226                 }
 227
 228                 if (c & IN6PTON_DOT) {
 229                         ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
 230                         if (ret > 0) {
 231                                 d += 4;
 232                                 break;
 233                         }
 234                         goto out;
 235                 }
 236
 237                 w = (w << 4) | (0xff & c);
 238                 state = IN6PTON_COLON_1 | IN6PTON_DELIM;
 239                 if (!(w & 0xf000)) {
 240                         state |= IN6PTON_XDIGIT;
 241                 }
 242                 if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
 243                         state |= IN6PTON_COLON_1_2;
 244                         state &= ~IN6PTON_DELIM;
 245                 }
 246                 if (d + 2 >= dbuf + sizeof(dbuf)) {
 247                         state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
 248                 }
 249 cont:
 250                 if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
 251                     d + 4 == dbuf + sizeof(dbuf)) {
 252                         state |= IN6PTON_DOT;
 253                 }
 254                 if (d >= dbuf + sizeof(dbuf)) {
 255                         state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
 256                 }
 257                 s++;
 258                 srclen--;
 259         }
 260
 261         i = 15; d--;
 262
 263         if (dc) {
 264                 while(d >= dc)
 265                         dst[i--] = *d--;
 266                 while(i >= dc - dbuf)
 267                         dst[i--] = 0;
 268                 while(i >= 0)
 269                         dst[i--] = *d--;
 270         } else
 271                 memcpy(dst, dbuf, sizeof(dbuf));
 272
 273         ret = 1;
 274 out:
 275         if (end)
 276                 *end = s;
 277         return ret;
 278 }
 279 EXPORT_SYMBOL(in6_pton);
 280
 281 void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
 282                               __be32 from, __be32 to, int pseudohdr)
 283 {
 284         __be32 diff[] = { ~from, to };
 285         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 286                 *sum = csum_fold(csum_partial(diff, sizeof(diff),
 287                                 ~csum_unfold(*sum)));
 288                 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
 289                         skb->csum = ~csum_partial(diff, sizeof(diff),
 290                                                 ~skb->csum);
 291         } else if (pseudohdr)
 292                 *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
 293                                 csum_unfold(*sum)));
 294 }
 295 EXPORT_SYMBOL(inet_proto_csum_replace4);
 296
 297 void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
 298                                const __be32 *from, const __be32 *to,
 299                                int pseudohdr)
 300 {
 301         __be32 diff[] = {
 302                 ~from[0], ~from[1], ~from[2], ~from[3],
 303                 to[0], to[1], to[2], to[3],
 304         };
 305         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 306                 *sum = csum_fold(csum_partial(diff, sizeof(diff),
 307                                  ~csum_unfold(*sum)));
 308                 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
 309                         skb->csum = ~csum_partial(diff, sizeof(diff),
 310                                                   ~skb->csum);
 311         } else if (pseudohdr)
 312                 *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
 313                                   csum_unfold(*sum)));
 314 }
 315 EXPORT_SYMBOL(inet_proto_csum_replace16);
 316
 317 int mac_pton(const char *s, u8 *mac)
 318 {
 319         int i;
 320
 321         /* XX:XX:XX:XX:XX:XX */
 322         if (strlen(s) < 3 * ETH_ALEN - 1)
 323                 return 0;
 324
 325         /* Don't dirty result unless string is valid MAC. */
 326         for (i = 0; i < ETH_ALEN; i++) {
 327                 if (!strchr("0123456789abcdefABCDEF", s[i * 3]))
 328                         return 0;
 329                 if (!strchr("0123456789abcdefABCDEF", s[i * 3 + 1]))
 330                         return 0;
 331                 if (i != ETH_ALEN - 1 && s[i * 3 + 2] != ':')
 332                         return 0;
 333         }
 334         for (i = 0; i < ETH_ALEN; i++) {
 335                 mac[i] = (hex_to_bin(s[i * 3]) << 4) | hex_to_bin(s[i * 3 + 1]);
 336         }
 337         return 1;
 338 }
 339 EXPORT_SYMBOL(mac_pton);