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 #include <linux/export.h>
  23
  24 #if IS_ENABLED(CONFIG_IPV6)
  25
  26 static size_t rpc_ntop6_noscopeid(const struct sockaddr *sap,
  27                                   char *buf, const int buflen)
  28 {
  29         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  30         const struct in6_addr *addr = &sin6->sin6_addr;
  31
  32         /*
  33          * RFC 4291, Section 2.2.2
  34          *
  35          * Shorthanded ANY address
  36          */
  37         if (ipv6_addr_any(addr))
  38                 return snprintf(buf, buflen, "::");
  39
  40         /*
  41          * RFC 4291, Section 2.2.2
  42          *
  43          * Shorthanded loopback address
  44          */
  45         if (ipv6_addr_loopback(addr))
  46                 return snprintf(buf, buflen, "::1");
  47
  48         /*
  49          * RFC 4291, Section 2.2.3
  50          *
  51          * Special presentation address format for mapped v4
  52          * addresses.
  53          */
  54         if (ipv6_addr_v4mapped(addr))
  55                 return snprintf(buf, buflen, "::ffff:%pI4",
  56                                         &addr->s6_addr32[3]);
  57
  58         /*
  59          * RFC 4291, Section 2.2.1
  60          */
  61         return snprintf(buf, buflen, "%pI6c", addr);
  62 }
  63
  64 static size_t rpc_ntop6(const struct sockaddr *sap,
  65                         char *buf, const size_t buflen)
  66 {
  67         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  68         char scopebuf[IPV6_SCOPE_ID_LEN];
  69         size_t len;
  70         int rc;
  71
  72         len = rpc_ntop6_noscopeid(sap, buf, buflen);
  73         if (unlikely(len == 0))
  74                 return len;
  75
  76         if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
  77                 return len;
  78         if (sin6->sin6_scope_id == 0)
  79                 return len;
  80
  81         rc = snprintf(scopebuf, sizeof(scopebuf), "%c%u",
  82                         IPV6_SCOPE_DELIMITER, sin6->sin6_scope_id);
  83         if (unlikely((size_t)rc > sizeof(scopebuf)))
  84                 return 0;
  85
  86         len += rc;
  87         if (unlikely(len > buflen))
  88                 return 0;
  89
  90         strcat(buf, scopebuf);
  91         return len;
  92 }
  93
  94 #else   /* !IS_ENABLED(CONFIG_IPV6) */
  95
  96 static size_t rpc_ntop6_noscopeid(const struct sockaddr *sap,
  97                                   char *buf, const int buflen)
  98 {
  99         return 0;
 100 }
 101
 102 static size_t rpc_ntop6(const struct sockaddr *sap,
 103                         char *buf, const size_t buflen)
 104 {
 105         return 0;
 106 }
 107
 108 #endif  /* !IS_ENABLED(CONFIG_IPV6) */
 109
 110 static int rpc_ntop4(const struct sockaddr *sap,
 111                      char *buf, const size_t buflen)
 112 {
 113         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 114
 115         return snprintf(buf, buflen, "%pI4", &sin->sin_addr);
 116 }
 117
 118 /**
 119  * rpc_ntop - construct a presentation address in @buf
 120  * @sap: socket address
 121  * @buf: construction area
 122  * @buflen: size of @buf, in bytes
 123  *
 124  * Plants a %NUL-terminated string in @buf and returns the length
 125  * of the string, excluding the %NUL.  Otherwise zero is returned.
 126  */
 127 size_t rpc_ntop(const struct sockaddr *sap, char *buf, const size_t buflen)
 128 {
 129         switch (sap->sa_family) {
 130         case AF_INET:
 131                 return rpc_ntop4(sap, buf, buflen);
 132         case AF_INET6:
 133                 return rpc_ntop6(sap, buf, buflen);
 134         }
 135
 136         return 0;
 137 }
 138 EXPORT_SYMBOL_GPL(rpc_ntop);
 139
 140 static size_t rpc_pton4(const char *buf, const size_t buflen,
 141                         struct sockaddr *sap, const size_t salen)
 142 {
 143         struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 144         u8 *addr = (u8 *)&sin->sin_addr.s_addr;
 145
 146         if (buflen > INET_ADDRSTRLEN || salen < sizeof(struct sockaddr_in))
 147                 return 0;
 148
 149         memset(sap, 0, sizeof(struct sockaddr_in));
 150
 151         if (in4_pton(buf, buflen, addr, '\0', NULL) == 0)
 152                 return 0;
 153
 154         sin->sin_family = AF_INET;
 155         return sizeof(struct sockaddr_in);
 156 }
 157
 158 #if IS_ENABLED(CONFIG_IPV6)
 159 static int rpc_parse_scope_id(struct net *net, const char *buf,
 160                               const size_t buflen, const char *delim,
 161                               struct sockaddr_in6 *sin6)
 162 {
 163         char *p;
 164         size_t len;
 165
 166         if ((buf + buflen) == delim)
 167                 return 1;
 168
 169         if (*delim != IPV6_SCOPE_DELIMITER)
 170                 return 0;
 171
 172         if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
 173                 return 0;
 174
 175         len = (buf + buflen) - delim - 1;
 176         p = kstrndup(delim + 1, len, GFP_KERNEL);
 177         if (p) {
 178                 unsigned long scope_id = 0;
 179                 struct net_device *dev;
 180
 181                 dev = dev_get_by_name(net, p);
 182                 if (dev != NULL) {
 183                         scope_id = dev->ifindex;
 184                         dev_put(dev);
 185                 } else {
 186                         if (strict_strtoul(p, 10, &scope_id) == 0) {
 187                                 kfree(p);
 188                                 return 0;
 189                         }
 190                 }
 191
 192                 kfree(p);
 193
 194                 sin6->sin6_scope_id = scope_id;
 195                 return 1;
 196         }
 197
 198         return 0;
 199 }
 200
 201 static size_t rpc_pton6(struct net *net, const char *buf, const size_t buflen,
 202                         struct sockaddr *sap, const size_t salen)
 203 {
 204         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
 205         u8 *addr = (u8 *)&sin6->sin6_addr.in6_u;
 206         const char *delim;
 207
 208         if (buflen > (INET6_ADDRSTRLEN + IPV6_SCOPE_ID_LEN) ||
 209             salen < sizeof(struct sockaddr_in6))
 210                 return 0;
 211
 212         memset(sap, 0, sizeof(struct sockaddr_in6));
 213
 214         if (in6_pton(buf, buflen, addr, IPV6_SCOPE_DELIMITER, &delim) == 0)
 215                 return 0;
 216
 217         if (!rpc_parse_scope_id(net, buf, buflen, delim, sin6))
 218                 return 0;
 219
 220         sin6->sin6_family = AF_INET6;
 221         return sizeof(struct sockaddr_in6);
 222 }
 223 #else
 224 static size_t rpc_pton6(struct net *net, const char *buf, const size_t buflen,
 225                         struct sockaddr *sap, const size_t salen)
 226 {
 227         return 0;
 228 }
 229 #endif
 230
 231 /**
 232  * rpc_pton - Construct a sockaddr in @sap
 233  * @net: applicable network namespace
 234  * @buf: C string containing presentation format IP address
 235  * @buflen: length of presentation address in bytes
 236  * @sap: buffer into which to plant socket address
 237  * @salen: size of buffer in bytes
 238  *
 239  * Returns the size of the socket address if successful; otherwise
 240  * zero is returned.
 241  *
 242  * Plants a socket address in @sap and returns the size of the
 243  * socket address, if successful.  Returns zero if an error
 244  * occurred.
 245  */
 246 size_t rpc_pton(struct net *net, const char *buf, const size_t buflen,
 247                 struct sockaddr *sap, const size_t salen)
 248 {
 249         unsigned int i;
 250
 251         for (i = 0; i < buflen; i++)
 252                 if (buf[i] == ':')
 253                         return rpc_pton6(net, buf, buflen, sap, salen);
 254         return rpc_pton4(buf, buflen, sap, salen);
 255 }
 256 EXPORT_SYMBOL_GPL(rpc_pton);
 257
 258 /**
 259  * rpc_sockaddr2uaddr - Construct a universal address string from @sap.
 260  * @sap: socket address
 261  * @gfp_flags: allocation mode
 262  *
 263  * Returns a %NUL-terminated string in dynamically allocated memory;
 264  * otherwise NULL is returned if an error occurred.  Caller must
 265  * free the returned string.
 266  */
 267 char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)
 268 {
 269         char portbuf[RPCBIND_MAXUADDRPLEN];
 270         char addrbuf[RPCBIND_MAXUADDRLEN];
 271         unsigned short port;
 272
 273         switch (sap->sa_family) {
 274         case AF_INET:
 275                 if (rpc_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
 276                         return NULL;
 277                 port = ntohs(((struct sockaddr_in *)sap)->sin_port);
 278                 break;
 279         case AF_INET6:
 280                 if (rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
 281                         return NULL;
 282                 port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
 283                 break;
 284         default:
 285                 return NULL;
 286         }
 287
 288         if (snprintf(portbuf, sizeof(portbuf),
 289                      ".%u.%u", port >> 8, port & 0xff) > (int)sizeof(portbuf))
 290                 return NULL;
 291
 292         if (strlcat(addrbuf, portbuf, sizeof(addrbuf)) > sizeof(addrbuf))
 293                 return NULL;
 294
 295         return kstrdup(addrbuf, gfp_flags);
 296 }
 297
 298 /**
 299  * rpc_uaddr2sockaddr - convert a universal address to a socket address.
 300  * @net: applicable network namespace
 301  * @uaddr: C string containing universal address to convert
 302  * @uaddr_len: length of universal address string
 303  * @sap: buffer into which to plant socket address
 304  * @salen: size of buffer
 305  *
 306  * @uaddr does not have to be '\0'-terminated, but strict_strtoul() and
 307  * rpc_pton() require proper string termination to be successful.
 308  *
 309  * Returns the size of the socket address if successful; otherwise
 310  * zero is returned.
 311  */
 312 size_t rpc_uaddr2sockaddr(struct net *net, const char *uaddr,
 313                           const size_t uaddr_len, struct sockaddr *sap,
 314                           const size_t salen)
 315 {
 316         char *c, buf[RPCBIND_MAXUADDRLEN + sizeof('\0')];
 317         unsigned long portlo, porthi;
 318         unsigned short port;
 319
 320         if (uaddr_len > RPCBIND_MAXUADDRLEN)
 321                 return 0;
 322
 323         memcpy(buf, uaddr, uaddr_len);
 324
 325         buf[uaddr_len] = '\0';
 326         c = strrchr(buf, '.');
 327         if (unlikely(c == NULL))
 328                 return 0;
 329         if (unlikely(strict_strtoul(c + 1, 10, &portlo) != 0))
 330                 return 0;
 331         if (unlikely(portlo > 255))
 332                 return 0;
 333
 334         *c = '\0';
 335         c = strrchr(buf, '.');
 336         if (unlikely(c == NULL))
 337                 return 0;
 338         if (unlikely(strict_strtoul(c + 1, 10, &porthi) != 0))
 339                 return 0;
 340         if (unlikely(porthi > 255))
 341                 return 0;
 342
 343         port = (unsigned short)((porthi << 8) | portlo);
 344
 345         *c = '\0';
 346         if (rpc_pton(net, buf, strlen(buf), sap, salen) == 0)
 347                 return 0;
 348
 349         switch (sap->sa_family) {
 350         case AF_INET:
 351                 ((struct sockaddr_in *)sap)->sin_port = htons(port);
 352                 return sizeof(struct sockaddr_in);
 353         case AF_INET6:
 354                 ((struct sockaddr_in6 *)sap)->sin6_port = htons(port);
 355                 return sizeof(struct sockaddr_in6);
 356         }
 357
 358         return 0;
 359 }
 360 EXPORT_SYMBOL_GPL(rpc_uaddr2sockaddr);