net/sunrpc/addr.c

   1 /*
   2  * Copyright 2009, Oracle.  All rights reserved.
   3  *
   4  * Convert socket addresses to presentation addresses and universal
   5  * addresses, and vice versa.
   6  *
   7  * Universal addresses are introduced by RFC 1833 and further refined by
   8  * recent RFCs describing NFSv4.  The universal address format is part
   9  * of the external (network) interface provided by rpcbind version 3
  10  * and 4, and by NFSv4.  Such an address is a string containing a
  11  * presentation format IP address followed by a port number in
  12  * "hibyte.lobyte" format.
  13  *
  14  * IPv6 addresses can also include a scope ID, typically denoted by
  15  * a '%' followed by a device name or a non-negative integer.  Refer to
  16  * RFC 4291, Section 2.2 for details on IPv6 presentation formats.
  17  */
  18
  19 #include <net/ipv6.h>
  20 #include <linux/sunrpc/clnt.h>
  21
  22 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
  23
  24 static size_t rpc_ntop6_noscopeid(const struct sockaddr *sap,
  25                                   char *buf, const int buflen)
  26 {
  27         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  28         const struct in6_addr *addr = &sin6->sin6_addr;
  29
  30         /*
  31          * RFC 4291, Section 2.2.2
  32          *
  33          * Shorthanded ANY address
  34          */
  35         if (ipv6_addr_any(addr))
  36                 return snprintf(buf, buflen, "::");
  37
  38         /*
  39          * RFC 4291, Section 2.2.2
  40          *
  41          * Shorthanded loopback address
  42          */
  43         if (ipv6_addr_loopback(addr))
  44                 return snprintf(buf, buflen, "::1");
  45
  46         /*
  47          * RFC 4291, Section 2.2.3
  48          *
  49          * Special presentation address format for mapped v4
  50          * addresses.
  51          */
  52         if (ipv6_addr_v4mapped(addr))
  53                 return snprintf(buf, buflen, "::ffff:%pI4",
  54                                         &addr->s6_addr32[3]);
  55
  56         /*
  57          * RFC 4291, Section 2.2.1
  58          */
  59         return snprintf(buf, buflen, "%pI6c", addr);
  60 }
  61
  62 static size_t rpc_ntop6(const struct sockaddr *sap,
  63                         char *buf, const size_t buflen)
  64 {
  65         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  66         char scopebuf[IPV6_SCOPE_ID_LEN];
  67         size_t len;
  68         int rc;
  69
  70         len = rpc_ntop6_noscopeid(sap, buf, buflen);
  71         if (unlikely(len == 0))
  72                 return len;
  73
  74         if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
  75                 return len;
  76         if (sin6->sin6_scope_id == 0)
  77                 return len;
  78
  79         rc = snprintf(scopebuf, sizeof(scopebuf), "%c%u",
  80                         IPV6_SCOPE_DELIMITER, sin6->sin6_scope_id);
  81         if (unlikely((size_t)rc > sizeof(scopebuf)))
  82                 return 0;
  83
  84         len += rc;
  85         if (unlikely(len > buflen))
  86                 return 0;
  87
  88         strcat(buf, scopebuf);
  89         return len;
  90 }
  91
  92 #else   /* !(defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)) */
  93
  94 static size_t rpc_ntop6_noscopeid(const struct sockaddr *sap,
  95                                   char *buf, const int buflen)
  96 {
  97         return 0;
  98 }
  99
 100 static size_t rpc_ntop6(const struct sockaddr *sap,
 101                         char *buf, const size_t buflen)
 102 {
 103         return 0;
 104 }
 105
 106 #endif  /* !(defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)) */
 107
 108 static int rpc_ntop4(const struct sockaddr *sap,
 109                      char *buf, const size_t buflen)
 110 {
 111         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 112
 113         return snprintf(buf, buflen, "%pI4", &sin->sin_addr);
 114 }
 115
 116 /**
 117  * rpc_ntop - construct a presentation address in @buf
 118  * @sap: socket address
 119  * @buf: construction area
 120  * @buflen: size of @buf, in bytes
 121  *
 122  * Plants a %NUL-terminated string in @buf and returns the length
 123  * of the string, excluding the %NUL.  Otherwise zero is returned.
 124  */
 125 size_t rpc_ntop(const struct sockaddr *sap, char *buf, const size_t buflen)
 126 {
 127         switch (sap->sa_family) {
 128         case AF_INET:
 129                 return rpc_ntop4(sap, buf, buflen);
 130         case AF_INET6:
 131                 return rpc_ntop6(sap, buf, buflen);
 132         }
 133
 134         return 0;
 135 }
 136 EXPORT_SYMBOL_GPL(rpc_ntop);
 137
 138 static size_t rpc_pton4(const char *buf, const size_t buflen,
 139                         struct sockaddr *sap, const size_t salen)
 140 {
 141         struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 142         u8 *addr = (u8 *)&sin->sin_addr.s_addr;
 143
 144         if (buflen > INET_ADDRSTRLEN || salen < sizeof(struct sockaddr_in))
 145                 return 0;
 146
 147         memset(sap, 0, sizeof(struct sockaddr_in));
 148
 149         if (in4_pton(buf, buflen, addr, '\0', NULL) == 0)
 150                 return 0;
 151
 152         sin->sin_family = AF_INET;
 153         return sizeof(struct sockaddr_in);;
 154 }
 155
 156 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 157 static int rpc_parse_scope_id(const char *buf, const size_t buflen,
 158                               const char *delim, struct sockaddr_in6 *sin6)
 159 {
 160         char *p;
 161         size_t len;
 162
 163         if ((buf + buflen) == delim)
 164                 return 1;
 165
 166         if (*delim != IPV6_SCOPE_DELIMITER)
 167                 return 0;
 168
 169         if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
 170                 return 0;
 171
 172         len = (buf + buflen) - delim - 1;
 173         p = kstrndup(delim + 1, len, GFP_KERNEL);
 174         if (p) {
 175                 unsigned long scope_id = 0;
 176                 struct net_device *dev;
 177
 178                 dev = dev_get_by_name(&init_net, p);
 179                 if (dev != NULL) {
 180                         scope_id = dev->ifindex;
 181                         dev_put(dev);
 182                 } else {
 183                         if (strict_strtoul(p, 10, &scope_id) == 0) {
 184                                 kfree(p);
 185                                 return 0;
 186                         }
 187                 }
 188
 189                 kfree(p);
 190
 191                 sin6->sin6_scope_id = scope_id;
 192                 return 1;
 193         }
 194
 195         return 0;
 196 }
 197
 198 static size_t rpc_pton6(const char *buf, const size_t buflen,
 199                         struct sockaddr *sap, const size_t salen)
 200 {
 201         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
 202         u8 *addr = (u8 *)&sin6->sin6_addr.in6_u;
 203         const char *delim;
 204
 205         if (buflen > (INET6_ADDRSTRLEN + IPV6_SCOPE_ID_LEN) ||
 206             salen < sizeof(struct sockaddr_in6))
 207                 return 0;
 208
 209         memset(sap, 0, sizeof(struct sockaddr_in6));
 210
 211         if (in6_pton(buf, buflen, addr, IPV6_SCOPE_DELIMITER, &delim) == 0)
 212                 return 0;
 213
 214         if (!rpc_parse_scope_id(buf, buflen, delim, sin6))
 215                 return 0;
 216
 217         sin6->sin6_family = AF_INET6;
 218         return sizeof(struct sockaddr_in6);
 219 }
 220 #else
 221 static size_t rpc_pton6(const char *buf, const size_t buflen,
 222                         struct sockaddr *sap, const size_t salen)
 223 {
 224         return 0;
 225 }
 226 #endif
 227
 228 /**
 229  * rpc_pton - Construct a sockaddr in @sap
 230  * @buf: C string containing presentation format IP address
 231  * @buflen: length of presentation address in bytes
 232  * @sap: buffer into which to plant socket address
 233  * @salen: size of buffer in bytes
 234  *
 235  * Returns the size of the socket address if successful; otherwise
 236  * zero is returned.
 237  *
 238  * Plants a socket address in @sap and returns the size of the
 239  * socket address, if successful.  Returns zero if an error
 240  * occurred.
 241  */
 242 size_t rpc_pton(const char *buf, const size_t buflen,
 243                 struct sockaddr *sap, const size_t salen)
 244 {
 245         unsigned int i;
 246
 247         for (i = 0; i < buflen; i++)
 248                 if (buf[i] == ':')
 249                         return rpc_pton6(buf, buflen, sap, salen);
 250         return rpc_pton4(buf, buflen, sap, salen);
 251 }
 252 EXPORT_SYMBOL_GPL(rpc_pton);
 253
 254 /**
 255  * rpc_sockaddr2uaddr - Construct a universal address string from @sap.
 256  * @sap: socket address
 257  *
 258  * Returns a %NUL-terminated string in dynamically allocated memory;
 259  * otherwise NULL is returned if an error occurred.  Caller must
 260  * free the returned string.
 261  */
 262 char *rpc_sockaddr2uaddr(const struct sockaddr *sap)
 263 {
 264         char portbuf[RPCBIND_MAXUADDRPLEN];
 265         char addrbuf[RPCBIND_MAXUADDRLEN];
 266         unsigned short port;
 267
 268         switch (sap->sa_family) {
 269         case AF_INET:
 270                 if (rpc_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
 271                         return NULL;
 272                 port = ntohs(((struct sockaddr_in *)sap)->sin_port);
 273                 break;
 274         case AF_INET6:
 275                 if (rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
 276                         return NULL;
 277                 port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
 278                 break;
 279         default:
 280                 return NULL;
 281         }
 282
 283         if (snprintf(portbuf, sizeof(portbuf),
 284                      ".%u.%u", port >> 8, port & 0xff) > (int)sizeof(portbuf))
 285                 return NULL;
 286
 287         if (strlcat(addrbuf, portbuf, sizeof(addrbuf)) > sizeof(addrbuf))
 288                 return NULL;
 289
 290         return kstrdup(addrbuf, GFP_KERNEL);
 291 }
 292 EXPORT_SYMBOL_GPL(rpc_sockaddr2uaddr);
 293
 294 /**
 295  * rpc_uaddr2sockaddr - convert a universal address to a socket address.
 296  * @uaddr: C string containing universal address to convert
 297  * @uaddr_len: length of universal address string
 298  * @sap: buffer into which to plant socket address
 299  * @salen: size of buffer
 300  *
 301  * @uaddr does not have to be '\0'-terminated, but strict_strtoul() and
 302  * rpc_pton() require proper string termination to be successful.
 303  *
 304  * Returns the size of the socket address if successful; otherwise
 305  * zero is returned.
 306  */
 307 size_t rpc_uaddr2sockaddr(const char *uaddr, const size_t uaddr_len,
 308                           struct sockaddr *sap, const size_t salen)
 309 {
 310         char *c, buf[RPCBIND_MAXUADDRLEN + sizeof('\0')];
 311         unsigned long portlo, porthi;
 312         unsigned short port;
 313
 314         if (uaddr_len > RPCBIND_MAXUADDRLEN)
 315                 return 0;
 316
 317         memcpy(buf, uaddr, uaddr_len);
 318
 319         buf[uaddr_len] = '\0';
 320         c = strrchr(buf, '.');
 321         if (unlikely(c == NULL))
 322                 return 0;
 323         if (unlikely(strict_strtoul(c + 1, 10, &portlo) != 0))
 324                 return 0;
 325         if (unlikely(portlo > 255))
 326                 return 0;
 327
 328         *c = '\0';
 329         c = strrchr(buf, '.');
 330         if (unlikely(c == NULL))
 331                 return 0;
 332         if (unlikely(strict_strtoul(c + 1, 10, &porthi) != 0))
 333                 return 0;
 334         if (unlikely(porthi > 255))
 335                 return 0;
 336
 337         port = (unsigned short)((porthi << 8) | portlo);
 338
 339         *c = '\0';
 340         if (rpc_pton(buf, strlen(buf), sap, salen) == 0)
 341                 return 0;
 342
 343         switch (sap->sa_family) {
 344         case AF_INET:
 345                 ((struct sockaddr_in *)sap)->sin_port = htons(port);
 346                 return sizeof(struct sockaddr_in);
 347         case AF_INET6:
 348                 ((struct sockaddr_in6 *)sap)->sin6_port = htons(port);
 349                 return sizeof(struct sockaddr_in6);
 350         }
 351
 352         return 0;
 353 }
 354 EXPORT_SYMBOL_GPL(rpc_uaddr2sockaddr);