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
  31 #include <asm/byteorder.h>
  32 #include <asm/system.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         {
  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 xdigit2bin(char c, int delim)
  95 {
  96         if (c == delim || c == '\0')
  97                 return IN6PTON_DELIM;
  98         if (c == ':')
  99                 return IN6PTON_COLON_MASK;
 100         if (c == '.')
 101                 return IN6PTON_DOT;
 102         if (c >= '0' && c <= '9')
 103                 return (IN6PTON_XDIGIT | IN6PTON_DIGIT| (c - '0'));
 104         if (c >= 'a' && c <= 'f')
 105                 return (IN6PTON_XDIGIT | (c - 'a' + 10));
 106         if (c >= 'A' && c <= 'F')
 107                 return (IN6PTON_XDIGIT | (c - 'A' + 10));
 108         if (delim == -1)
 109                 return IN6PTON_DELIM;
 110         return IN6PTON_UNKNOWN;
 111 }
 112
 113 int in4_pton(const char *src, int srclen,
 114              u8 *dst,
 115              int delim, const char **end)
 116 {
 117         const char *s;
 118         u8 *d;
 119         u8 dbuf[4];
 120         int ret = 0;
 121         int i;
 122         int w = 0;
 123
 124         if (srclen < 0)
 125                 srclen = strlen(src);
 126         s = src;
 127         d = dbuf;
 128         i = 0;
 129         while(1) {
 130                 int c;
 131                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 132                 if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
 133                         goto out;
 134                 }
 135                 if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 136                         if (w == 0)
 137                                 goto out;
 138                         *d++ = w & 0xff;
 139                         w = 0;
 140                         i++;
 141                         if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 142                                 if (i != 4)
 143                                         goto out;
 144                                 break;
 145                         }
 146                         goto cont;
 147                 }
 148                 w = (w * 10) + c;
 149                 if ((w & 0xffff) > 255) {
 150                         goto out;
 151                 }
 152 cont:
 153                 if (i >= 4)
 154                         goto out;
 155                 s++;
 156                 srclen--;
 157         }
 158         ret = 1;
 159         memcpy(dst, dbuf, sizeof(dbuf));
 160 out:
 161         if (end)
 162                 *end = s;
 163         return ret;
 164 }
 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
 284 EXPORT_SYMBOL(in6_pton);
 285
 286 void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
 287                               __be32 from, __be32 to, int pseudohdr)
 288 {
 289         __be32 diff[] = { ~from, to };
 290         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 291                 *sum = csum_fold(csum_partial(diff, sizeof(diff),
 292                                 ~csum_unfold(*sum)));
 293                 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
 294                         skb->csum = ~csum_partial(diff, sizeof(diff),
 295                                                 ~skb->csum);
 296         } else if (pseudohdr)
 297                 *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
 298                                 csum_unfold(*sum)));
 299 }
 300 EXPORT_SYMBOL(inet_proto_csum_replace4);