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 <net/sock.h>
  28
  29 #include <asm/byteorder.h>
  30 #include <asm/system.h>
  31 #include <asm/uaccess.h>
  32
  33 int net_msg_warn __read_mostly = 1;
  34 EXPORT_SYMBOL(net_msg_warn);
  35
  36 DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
  37 /*
  38  * All net warning printk()s should be guarded by this function.
  39  */
  40 int net_ratelimit(void)
  41 {
  42         return __ratelimit(&net_ratelimit_state);
  43 }
  44 EXPORT_SYMBOL(net_ratelimit);
  45
  46 /*
  47  * Convert an ASCII string to binary IP.
  48  * This is outside of net/ipv4/ because various code that uses IP addresses
  49  * is otherwise not dependent on the TCP/IP stack.
  50  */
  51
  52 __be32 in_aton(const char *str)
  53 {
  54         unsigned long l;
  55         unsigned int val;
  56         int i;
  57
  58         l = 0;
  59         for (i = 0; i < 4; i++)
  60         {
  61                 l <<= 8;
  62                 if (*str != '\0')
  63                 {
  64                         val = 0;
  65                         while (*str != '\0' && *str != '.' && *str != '\n')
  66                         {
  67                                 val *= 10;
  68                                 val += *str - '0';
  69                                 str++;
  70                         }
  71                         l |= val;
  72                         if (*str != '\0')
  73                                 str++;
  74                 }
  75         }
  76         return(htonl(l));
  77 }
  78
  79 EXPORT_SYMBOL(in_aton);
  80
  81 #define IN6PTON_XDIGIT          0x00010000
  82 #define IN6PTON_DIGIT           0x00020000
  83 #define IN6PTON_COLON_MASK      0x00700000
  84 #define IN6PTON_COLON_1         0x00100000      /* single : requested */
  85 #define IN6PTON_COLON_2         0x00200000      /* second : requested */
  86 #define IN6PTON_COLON_1_2       0x00400000      /* :: requested */
  87 #define IN6PTON_DOT             0x00800000      /* . */
  88 #define IN6PTON_DELIM           0x10000000
  89 #define IN6PTON_NULL            0x20000000      /* first/tail */
  90 #define IN6PTON_UNKNOWN         0x40000000
  91
  92 static inline int xdigit2bin(char c, int delim)
  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         if (c >= '0' && c <= '9')
 101                 return (IN6PTON_XDIGIT | IN6PTON_DIGIT| (c - '0'));
 102         if (c >= 'a' && c <= 'f')
 103                 return (IN6PTON_XDIGIT | (c - 'a' + 10));
 104         if (c >= 'A' && c <= 'F')
 105                 return (IN6PTON_XDIGIT | (c - 'A' + 10));
 106         if (delim == -1)
 107                 return IN6PTON_DELIM;
 108         return IN6PTON_UNKNOWN;
 109 }
 110
 111 int in4_pton(const char *src, int srclen,
 112              u8 *dst,
 113              int delim, const char **end)
 114 {
 115         const char *s;
 116         u8 *d;
 117         u8 dbuf[4];
 118         int ret = 0;
 119         int i;
 120         int w = 0;
 121
 122         if (srclen < 0)
 123                 srclen = strlen(src);
 124         s = src;
 125         d = dbuf;
 126         i = 0;
 127         while(1) {
 128                 int c;
 129                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 130                 if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
 131                         goto out;
 132                 }
 133                 if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 134                         if (w == 0)
 135                                 goto out;
 136                         *d++ = w & 0xff;
 137                         w = 0;
 138                         i++;
 139                         if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 140                                 if (i != 4)
 141                                         goto out;
 142                                 break;
 143                         }
 144                         goto cont;
 145                 }
 146                 w = (w * 10) + c;
 147                 if ((w & 0xffff) > 255) {
 148                         goto out;
 149                 }
 150 cont:
 151                 if (i >= 4)
 152                         goto out;
 153                 s++;
 154                 srclen--;
 155         }
 156         ret = 1;
 157         memcpy(dst, dbuf, sizeof(dbuf));
 158 out:
 159         if (end)
 160                 *end = s;
 161         return ret;
 162 }
 163
 164 EXPORT_SYMBOL(in4_pton);
 165
 166 int in6_pton(const char *src, int srclen,
 167              u8 *dst,
 168              int delim, const char **end)
 169 {
 170         const char *s, *tok = NULL;
 171         u8 *d, *dc = NULL;
 172         u8 dbuf[16];
 173         int ret = 0;
 174         int i;
 175         int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
 176         int w = 0;
 177
 178         memset(dbuf, 0, sizeof(dbuf));
 179
 180         s = src;
 181         d = dbuf;
 182         if (srclen < 0)
 183                 srclen = strlen(src);
 184
 185         while (1) {
 186                 int c;
 187
 188                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 189                 if (!(c & state))
 190                         goto out;
 191                 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 192                         /* process one 16-bit word */
 193                         if (!(state & IN6PTON_NULL)) {
 194                                 *d++ = (w >> 8) & 0xff;
 195                                 *d++ = w & 0xff;
 196                         }
 197                         w = 0;
 198                         if (c & IN6PTON_DELIM) {
 199                                 /* We've processed last word */
 200                                 break;
 201                         }
 202                         /*
 203                          * COLON_1 => XDIGIT
 204                          * COLON_2 => XDIGIT|DELIM
 205                          * COLON_1_2 => COLON_2
 206                          */
 207                         switch (state & IN6PTON_COLON_MASK) {
 208                         case IN6PTON_COLON_2:
 209                                 dc = d;
 210                                 state = IN6PTON_XDIGIT | IN6PTON_DELIM;
 211                                 if (dc - dbuf >= sizeof(dbuf))
 212                                         state |= IN6PTON_NULL;
 213                                 break;
 214                         case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
 215                                 state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
 216                                 break;
 217                         case IN6PTON_COLON_1:
 218                                 state = IN6PTON_XDIGIT;
 219                                 break;
 220                         case IN6PTON_COLON_1_2:
 221                                 state = IN6PTON_COLON_2;
 222                                 break;
 223                         default:
 224                                 state = 0;
 225                         }
 226                         tok = s + 1;
 227                         goto cont;
 228                 }
 229
 230                 if (c & IN6PTON_DOT) {
 231                         ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
 232                         if (ret > 0) {
 233                                 d += 4;
 234                                 break;
 235                         }
 236                         goto out;
 237                 }
 238
 239                 w = (w << 4) | (0xff & c);
 240                 state = IN6PTON_COLON_1 | IN6PTON_DELIM;
 241                 if (!(w & 0xf000)) {
 242                         state |= IN6PTON_XDIGIT;
 243                 }
 244                 if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
 245                         state |= IN6PTON_COLON_1_2;
 246                         state &= ~IN6PTON_DELIM;
 247                 }
 248                 if (d + 2 >= dbuf + sizeof(dbuf)) {
 249                         state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
 250                 }
 251 cont:
 252                 if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
 253                     d + 4 == dbuf + sizeof(dbuf)) {
 254                         state |= IN6PTON_DOT;
 255                 }
 256                 if (d >= dbuf + sizeof(dbuf)) {
 257                         state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
 258                 }
 259                 s++;
 260                 srclen--;
 261         }
 262
 263         i = 15; d--;
 264
 265         if (dc) {
 266                 while(d >= dc)
 267                         dst[i--] = *d--;
 268                 while(i >= dc - dbuf)
 269                         dst[i--] = 0;
 270                 while(i >= 0)
 271                         dst[i--] = *d--;
 272         } else
 273                 memcpy(dst, dbuf, sizeof(dbuf));
 274
 275         ret = 1;
 276 out:
 277         if (end)
 278                 *end = s;
 279         return ret;
 280 }
 281
 282 EXPORT_SYMBOL(in6_pton);
 283
 284 void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
 285                               __be32 from, __be32 to, int pseudohdr)
 286 {
 287         __be32 diff[] = { ~from, to };
 288         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 289                 *sum = csum_fold(csum_partial(diff, sizeof(diff),
 290                                 ~csum_unfold(*sum)));
 291                 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
 292                         skb->csum = ~csum_partial(diff, sizeof(diff),
 293                                                 ~skb->csum);
 294         } else if (pseudohdr)
 295                 *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
 296                                 csum_unfold(*sum)));
 297 }
 298 EXPORT_SYMBOL(inet_proto_csum_replace4);