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