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/ctype.h>
  21 #include <linux/inet.h>
  22 #include <linux/mm.h>
  23 #include <linux/net.h>
  24 #include <linux/string.h>
  25 #include <linux/types.h>
  26 #include <linux/percpu.h>
  27 #include <linux/init.h>
  28 #include <linux/ratelimit.h>
  29 #include <linux/socket.h>
  30
  31 #include <net/sock.h>
  32 #include <net/net_ratelimit.h>
  33 #include <net/ipv6.h>
  34
  35 #include <asm/byteorder.h>
  36 #include <linux/uaccess.h>
  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 int 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 /**
 111  * in4_pton - convert an IPv4 address from literal to binary representation
 112  * @src: the start of the IPv4 address string
 113  * @srclen: the length of the string, -1 means strlen(src)
 114  * @dst: the binary (u8[4] array) representation of the IPv4 address
 115  * @delim: the delimiter of the IPv4 address in @src, -1 means no delimiter
 116  * @end: A pointer to the end of the parsed string will be placed here
 117  *
 118  * Return one on success, return zero when any error occurs
 119  * and @end will point to the end of the parsed string.
 120  *
 121  */
 122 int in4_pton(const char *src, int srclen,
 123              u8 *dst,
 124              int delim, const char **end)
 125 {
 126         const char *s;
 127         u8 *d;
 128         u8 dbuf[4];
 129         int ret = 0;
 130         int i;
 131         int w = 0;
 132
 133         if (srclen < 0)
 134                 srclen = strlen(src);
 135         s = src;
 136         d = dbuf;
 137         i = 0;
 138         while (1) {
 139                 int c;
 140                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 141                 if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
 142                         goto out;
 143                 }
 144                 if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 145                         if (w == 0)
 146                                 goto out;
 147                         *d++ = w & 0xff;
 148                         w = 0;
 149                         i++;
 150                         if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 151                                 if (i != 4)
 152                                         goto out;
 153                                 break;
 154                         }
 155                         goto cont;
 156                 }
 157                 w = (w * 10) + c;
 158                 if ((w & 0xffff) > 255) {
 159                         goto out;
 160                 }
 161 cont:
 162                 if (i >= 4)
 163                         goto out;
 164                 s++;
 165                 srclen--;
 166         }
 167         ret = 1;
 168         memcpy(dst, dbuf, sizeof(dbuf));
 169 out:
 170         if (end)
 171                 *end = s;
 172         return ret;
 173 }
 174 EXPORT_SYMBOL(in4_pton);
 175
 176 /**
 177  * in6_pton - convert an IPv6 address from literal to binary representation
 178  * @src: the start of the IPv6 address string
 179  * @srclen: the length of the string, -1 means strlen(src)
 180  * @dst: the binary (u8[16] array) representation of the IPv6 address
 181  * @delim: the delimiter of the IPv6 address in @src, -1 means no delimiter
 182  * @end: A pointer to the end of the parsed string will be placed here
 183  *
 184  * Return one on success, return zero when any error occurs
 185  * and @end will point to the end of the parsed string.
 186  *
 187  */
 188 int in6_pton(const char *src, int srclen,
 189              u8 *dst,
 190              int delim, const char **end)
 191 {
 192         const char *s, *tok = NULL;
 193         u8 *d, *dc = NULL;
 194         u8 dbuf[16];
 195         int ret = 0;
 196         int i;
 197         int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
 198         int w = 0;
 199
 200         memset(dbuf, 0, sizeof(dbuf));
 201
 202         s = src;
 203         d = dbuf;
 204         if (srclen < 0)
 205                 srclen = strlen(src);
 206
 207         while (1) {
 208                 int c;
 209
 210                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 211                 if (!(c & state))
 212                         goto out;
 213                 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 214                         /* process one 16-bit word */
 215                         if (!(state & IN6PTON_NULL)) {
 216                                 *d++ = (w >> 8) & 0xff;
 217                                 *d++ = w & 0xff;
 218                         }
 219                         w = 0;
 220                         if (c & IN6PTON_DELIM) {
 221                                 /* We've processed last word */
 222                                 break;
 223                         }
 224                         /*
 225                          * COLON_1 => XDIGIT
 226                          * COLON_2 => XDIGIT|DELIM
 227                          * COLON_1_2 => COLON_2
 228                          */
 229                         switch (state & IN6PTON_COLON_MASK) {
 230                         case IN6PTON_COLON_2:
 231                                 dc = d;
 232                                 state = IN6PTON_XDIGIT | IN6PTON_DELIM;
 233                                 if (dc - dbuf >= sizeof(dbuf))
 234                                         state |= IN6PTON_NULL;
 235                                 break;
 236                         case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
 237                                 state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
 238                                 break;
 239                         case IN6PTON_COLON_1:
 240                                 state = IN6PTON_XDIGIT;
 241                                 break;
 242                         case IN6PTON_COLON_1_2:
 243                                 state = IN6PTON_COLON_2;
 244                                 break;
 245                         default:
 246                                 state = 0;
 247                         }
 248                         tok = s + 1;
 249                         goto cont;
 250                 }
 251
 252                 if (c & IN6PTON_DOT) {
 253                         ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
 254                         if (ret > 0) {
 255                                 d += 4;
 256                                 break;
 257                         }
 258                         goto out;
 259                 }
 260
 261                 w = (w << 4) | (0xff & c);
 262                 state = IN6PTON_COLON_1 | IN6PTON_DELIM;
 263                 if (!(w & 0xf000)) {
 264                         state |= IN6PTON_XDIGIT;
 265                 }
 266                 if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
 267                         state |= IN6PTON_COLON_1_2;
 268                         state &= ~IN6PTON_DELIM;
 269                 }
 270                 if (d + 2 >= dbuf + sizeof(dbuf)) {
 271                         state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
 272                 }
 273 cont:
 274                 if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
 275                     d + 4 == dbuf + sizeof(dbuf)) {
 276                         state |= IN6PTON_DOT;
 277                 }
 278                 if (d >= dbuf + sizeof(dbuf)) {
 279                         state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
 280                 }
 281                 s++;
 282                 srclen--;
 283         }
 284
 285         i = 15; d--;
 286
 287         if (dc) {
 288                 while (d >= dc)
 289                         dst[i--] = *d--;
 290                 while (i >= dc - dbuf)
 291                         dst[i--] = 0;
 292                 while (i >= 0)
 293                         dst[i--] = *d--;
 294         } else
 295                 memcpy(dst, dbuf, sizeof(dbuf));
 296
 297         ret = 1;
 298 out:
 299         if (end)
 300                 *end = s;
 301         return ret;
 302 }
 303 EXPORT_SYMBOL(in6_pton);
 304
 305 static int inet4_pton(const char *src, u16 port_num,
 306                 struct sockaddr_storage *addr)
 307 {
 308         struct sockaddr_in *addr4 = (struct sockaddr_in *)addr;
 309         int srclen = strlen(src);
 310
 311         if (srclen > INET_ADDRSTRLEN)
 312                 return -EINVAL;
 313
 314         if (in4_pton(src, srclen, (u8 *)&addr4->sin_addr.s_addr,
 315                      '\n', NULL) == 0)
 316                 return -EINVAL;
 317
 318         addr4->sin_family = AF_INET;
 319         addr4->sin_port = htons(port_num);
 320
 321         return 0;
 322 }
 323
 324 static int inet6_pton(struct net *net, const char *src, u16 port_num,
 325                 struct sockaddr_storage *addr)
 326 {
 327         struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)addr;
 328         const char *scope_delim;
 329         int srclen = strlen(src);
 330
 331         if (srclen > INET6_ADDRSTRLEN)
 332                 return -EINVAL;
 333
 334         if (in6_pton(src, srclen, (u8 *)&addr6->sin6_addr.s6_addr,
 335                      '%', &scope_delim) == 0)
 336                 return -EINVAL;
 337
 338         if (ipv6_addr_type(&addr6->sin6_addr) & IPV6_ADDR_LINKLOCAL &&
 339             src + srclen != scope_delim && *scope_delim == '%') {
 340                 struct net_device *dev;
 341                 char scope_id[16];
 342                 size_t scope_len = min_t(size_t, sizeof(scope_id) - 1,
 343                                          src + srclen - scope_delim - 1);
 344
 345                 memcpy(scope_id, scope_delim + 1, scope_len);
 346                 scope_id[scope_len] = '\0';
 347
 348                 dev = dev_get_by_name(net, scope_id);
 349                 if (dev) {
 350                         addr6->sin6_scope_id = dev->ifindex;
 351                         dev_put(dev);
 352                 } else if (kstrtouint(scope_id, 0, &addr6->sin6_scope_id)) {
 353                         return -EINVAL;
 354                 }
 355         }
 356
 357         addr6->sin6_family = AF_INET6;
 358         addr6->sin6_port = htons(port_num);
 359
 360         return 0;
 361 }
 362
 363 /**
 364  * inet_pton_with_scope - convert an IPv4/IPv6 and port to socket address
 365  * @net: net namespace (used for scope handling)
 366  * @af: address family, AF_INET, AF_INET6 or AF_UNSPEC for either
 367  * @src: the start of the address string
 368  * @port: the start of the port string (or NULL for none)
 369  * @addr: output socket address
 370  *
 371  * Return zero on success, return errno when any error occurs.
 372  */
 373 int inet_pton_with_scope(struct net *net, __kernel_sa_family_t af,
 374                 const char *src, const char *port, struct sockaddr_storage *addr)
 375 {
 376         u16 port_num;
 377         int ret = -EINVAL;
 378
 379         if (port) {
 380                 if (kstrtou16(port, 0, &port_num))
 381                         return -EINVAL;
 382         } else {
 383                 port_num = 0;
 384         }
 385
 386         switch (af) {
 387         case AF_INET:
 388                 ret = inet4_pton(src, port_num, addr);
 389                 break;
 390         case AF_INET6:
 391                 ret = inet6_pton(net, src, port_num, addr);
 392                 break;
 393         case AF_UNSPEC:
 394                 ret = inet4_pton(src, port_num, addr);
 395                 if (ret)
 396                         ret = inet6_pton(net, src, port_num, addr);
 397                 break;
 398         default:
 399                 pr_err("unexpected address family %d\n", af);
 400         };
 401
 402         return ret;
 403 }
 404 EXPORT_SYMBOL(inet_pton_with_scope);
 405
 406 void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
 407                               __be32 from, __be32 to, bool pseudohdr)
 408 {
 409         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 410                 csum_replace4(sum, from, to);
 411                 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
 412                         skb->csum = ~csum_add(csum_sub(~(skb->csum),
 413                                                        (__force __wsum)from),
 414                                               (__force __wsum)to);
 415         } else if (pseudohdr)
 416                 *sum = ~csum_fold(csum_add(csum_sub(csum_unfold(*sum),
 417                                                     (__force __wsum)from),
 418                                            (__force __wsum)to));
 419 }
 420 EXPORT_SYMBOL(inet_proto_csum_replace4);
 421
 422 void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
 423                                const __be32 *from, const __be32 *to,
 424                                bool pseudohdr)
 425 {
 426         __be32 diff[] = {
 427                 ~from[0], ~from[1], ~from[2], ~from[3],
 428                 to[0], to[1], to[2], to[3],
 429         };
 430         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 431                 *sum = csum_fold(csum_partial(diff, sizeof(diff),
 432                                  ~csum_unfold(*sum)));
 433                 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
 434                         skb->csum = ~csum_partial(diff, sizeof(diff),
 435                                                   ~skb->csum);
 436         } else if (pseudohdr)
 437                 *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
 438                                   csum_unfold(*sum)));
 439 }
 440 EXPORT_SYMBOL(inet_proto_csum_replace16);
 441
 442 void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
 443                                      __wsum diff, bool pseudohdr)
 444 {
 445         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 446                 *sum = csum_fold(csum_add(diff, ~csum_unfold(*sum)));
 447                 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
 448                         skb->csum = ~csum_add(diff, ~skb->csum);
 449         } else if (pseudohdr) {
 450                 *sum = ~csum_fold(csum_add(diff, csum_unfold(*sum)));
 451         }
 452 }
 453 EXPORT_SYMBOL(inet_proto_csum_replace_by_diff);