linux/net/core/utils.c
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   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
  33int net_msg_warn __read_mostly = 1;
  34EXPORT_SYMBOL(net_msg_warn);
  35
  36DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
  37/*
  38 * All net warning printk()s should be guarded by this function.
  39 */
  40int net_ratelimit(void)
  41{
  42        return __ratelimit(&net_ratelimit_state);
  43}
  44EXPORT_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
  79EXPORT_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
  92static 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
 111int 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                }
 150cont:
 151                if (i >= 4)
 152                        goto out;
 153                s++;
 154                srclen--;
 155        }
 156        ret = 1;
 157        memcpy(dst, dbuf, sizeof(dbuf));
 158out:
 159        if (end)
 160                *end = s;
 161        return ret;
 162}
 163
 164EXPORT_SYMBOL(in4_pton);
 165
 166int 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                }
 251cont:
 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;
 276out:
 277        if (end)
 278                *end = s;
 279        return ret;
 280}
 281
 282EXPORT_SYMBOL(in6_pton);
 283
 284void 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}
 298EXPORT_SYMBOL(inet_proto_csum_replace4);
 299
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