net/sunrpc/addr.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright 2009, Oracle.  All rights reserved.
   4  *
   5  * Convert socket addresses to presentation addresses and universal
   6  * addresses, and vice versa.
   7  *
   8  * Universal addresses are introduced by RFC 1833 and further refined by
   9  * recent RFCs describing NFSv4.  The universal address format is part
  10  * of the external (network) interface provided by rpcbind version 3
  11  * and 4, and by NFSv4.  Such an address is a string containing a
  12  * presentation format IP address followed by a port number in
  13  * "hibyte.lobyte" format.
  14  *
  15  * IPv6 addresses can also include a scope ID, typically denoted by
  16  * a '%' followed by a device name or a non-negative integer.  Refer to
  17  * RFC 4291, Section 2.2 for details on IPv6 presentation formats.
  18  */
  19
  20 #include <net/ipv6.h>
  21 #include <linux/sunrpc/addr.h>
  22 #include <linux/sunrpc/msg_prot.h>
  23 #include <linux/slab.h>
  24 #include <linux/export.h>
  25
  26 #if IS_ENABLED(CONFIG_IPV6)
  27
  28 static size_t rpc_ntop6_noscopeid(const struct sockaddr *sap,
  29                                   char *buf, const int buflen)
  30 {
  31         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  32         const struct in6_addr *addr = &sin6->sin6_addr;
  33
  34         /*
  35          * RFC 4291, Section 2.2.2
  36          *
  37          * Shorthanded ANY address
  38          */
  39         if (ipv6_addr_any(addr))
  40                 return snprintf(buf, buflen, "::");
  41
  42         /*
  43          * RFC 4291, Section 2.2.2
  44          *
  45          * Shorthanded loopback address
  46          */
  47         if (ipv6_addr_loopback(addr))
  48                 return snprintf(buf, buflen, "::1");
  49
  50         /*
  51          * RFC 4291, Section 2.2.3
  52          *
  53          * Special presentation address format for mapped v4
  54          * addresses.
  55          */
  56         if (ipv6_addr_v4mapped(addr))
  57                 return snprintf(buf, buflen, "::ffff:%pI4",
  58                                         &addr->s6_addr32[3]);
  59
  60         /*
  61          * RFC 4291, Section 2.2.1
  62          */
  63         return snprintf(buf, buflen, "%pI6c", addr);
  64 }
  65
  66 static size_t rpc_ntop6(const struct sockaddr *sap,
  67                         char *buf, const size_t buflen)
  68 {
  69         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  70         char scopebuf[IPV6_SCOPE_ID_LEN];
  71         size_t len;
  72         int rc;
  73
  74         len = rpc_ntop6_noscopeid(sap, buf, buflen);
  75         if (unlikely(len == 0))
  76                 return len;
  77
  78         if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
  79                 return len;
  80         if (sin6->sin6_scope_id == 0)
  81                 return len;
  82
  83         rc = snprintf(scopebuf, sizeof(scopebuf), "%c%u",
  84                         IPV6_SCOPE_DELIMITER, sin6->sin6_scope_id);
  85         if (unlikely((size_t)rc >= sizeof(scopebuf)))
  86                 return 0;
  87
  88         len += rc;
  89         if (unlikely(len >= buflen))
  90                 return 0;
  91
  92         strcat(buf, scopebuf);
  93         return len;
  94 }
  95
  96 #else   /* !IS_ENABLED(CONFIG_IPV6) */
  97
  98 static size_t rpc_ntop6_noscopeid(const struct sockaddr *sap,
  99                                   char *buf, const int buflen)
 100 {
 101         return 0;
 102 }
 103
 104 static size_t rpc_ntop6(const struct sockaddr *sap,
 105                         char *buf, const size_t buflen)
 106 {
 107         return 0;
 108 }
 109
 110 #endif  /* !IS_ENABLED(CONFIG_IPV6) */
 111
 112 static int rpc_ntop4(const struct sockaddr *sap,
 113                      char *buf, const size_t buflen)
 114 {
 115         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 116
 117         return snprintf(buf, buflen, "%pI4", &sin->sin_addr);
 118 }
 119
 120 /**
 121  * rpc_ntop - construct a presentation address in @buf
 122  * @sap: socket address
 123  * @buf: construction area
 124  * @buflen: size of @buf, in bytes
 125  *
 126  * Plants a %NUL-terminated string in @buf and returns the length
 127  * of the string, excluding the %NUL.  Otherwise zero is returned.
 128  */
 129 size_t rpc_ntop(const struct sockaddr *sap, char *buf, const size_t buflen)
 130 {
 131         switch (sap->sa_family) {
 132         case AF_INET:
 133                 return rpc_ntop4(sap, buf, buflen);
 134         case AF_INET6:
 135                 return rpc_ntop6(sap, buf, buflen);
 136         }
 137
 138         return 0;
 139 }
 140 EXPORT_SYMBOL_GPL(rpc_ntop);
 141
 142 static size_t rpc_pton4(const char *buf, const size_t buflen,
 143                         struct sockaddr *sap, const size_t salen)
 144 {
 145         struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 146         u8 *addr = (u8 *)&sin->sin_addr.s_addr;
 147
 148         if (buflen > INET_ADDRSTRLEN || salen < sizeof(struct sockaddr_in))
 149                 return 0;
 150
 151         memset(sap, 0, sizeof(struct sockaddr_in));
 152
 153         if (in4_pton(buf, buflen, addr, '\0', NULL) == 0)
 154                 return 0;
 155
 156         sin->sin_family = AF_INET;
 157         return sizeof(struct sockaddr_in);
 158 }
 159
 160 #if IS_ENABLED(CONFIG_IPV6)
 161 static int rpc_parse_scope_id(struct net *net, const char *buf,
 162                               const size_t buflen, const char *delim,
 163                               struct sockaddr_in6 *sin6)
 164 {
 165         char p[IPV6_SCOPE_ID_LEN + 1];
 166         size_t len;
 167         u32 scope_id = 0;
 168         struct net_device *dev;
 169
 170         if ((buf + buflen) == delim)
 171                 return 1;
 172
 173         if (*delim != IPV6_SCOPE_DELIMITER)
 174                 return 0;
 175
 176         if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
 177                 return 0;
 178
 179         len = (buf + buflen) - delim - 1;
 180         if (len > IPV6_SCOPE_ID_LEN)
 181                 return 0;
 182
 183         memcpy(p, delim + 1, len);
 184         p[len] = 0;
 185
 186         dev = dev_get_by_name(net, p);
 187         if (dev != NULL) {
 188                 scope_id = dev->ifindex;
 189                 dev_put(dev);
 190         } else {
 191                 if (kstrtou32(p, 10, &scope_id) != 0)
 192                         return 0;
 193         }
 194
 195         sin6->sin6_scope_id = scope_id;
 196         return 1;
 197 }
 198
 199 static size_t rpc_pton6(struct net *net, 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(net, 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(struct net *net, 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  * @net: applicable network namespace
 232  * @buf: C string containing presentation format IP address
 233  * @buflen: length of presentation address in bytes
 234  * @sap: buffer into which to plant socket address
 235  * @salen: size of buffer in bytes
 236  *
 237  * Returns the size of the socket address if successful; otherwise
 238  * zero is returned.
 239  *
 240  * Plants a socket address in @sap and returns the size of the
 241  * socket address, if successful.  Returns zero if an error
 242  * occurred.
 243  */
 244 size_t rpc_pton(struct net *net, const char *buf, const size_t buflen,
 245                 struct sockaddr *sap, const size_t salen)
 246 {
 247         unsigned int i;
 248
 249         for (i = 0; i < buflen; i++)
 250                 if (buf[i] == ':')
 251                         return rpc_pton6(net, buf, buflen, sap, salen);
 252         return rpc_pton4(buf, buflen, sap, salen);
 253 }
 254 EXPORT_SYMBOL_GPL(rpc_pton);
 255
 256 /**
 257  * rpc_sockaddr2uaddr - Construct a universal address string from @sap.
 258  * @sap: socket address
 259  * @gfp_flags: allocation mode
 260  *
 261  * Returns a %NUL-terminated string in dynamically allocated memory;
 262  * otherwise NULL is returned if an error occurred.  Caller must
 263  * free the returned string.
 264  */
 265 char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)
 266 {
 267         char portbuf[RPCBIND_MAXUADDRPLEN];
 268         char addrbuf[RPCBIND_MAXUADDRLEN];
 269         unsigned short port;
 270
 271         switch (sap->sa_family) {
 272         case AF_INET:
 273                 if (rpc_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
 274                         return NULL;
 275                 port = ntohs(((struct sockaddr_in *)sap)->sin_port);
 276                 break;
 277         case AF_INET6:
 278                 if (rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
 279                         return NULL;
 280                 port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
 281                 break;
 282         default:
 283                 return NULL;
 284         }
 285
 286         if (snprintf(portbuf, sizeof(portbuf),
 287                      ".%u.%u", port >> 8, port & 0xff) >= (int)sizeof(portbuf))
 288                 return NULL;
 289
 290         if (strlcat(addrbuf, portbuf, sizeof(addrbuf)) >= sizeof(addrbuf))
 291                 return NULL;
 292
 293         return kstrdup(addrbuf, gfp_flags);
 294 }
 295
 296 /**
 297  * rpc_uaddr2sockaddr - convert a universal address to a socket address.
 298  * @net: applicable network namespace
 299  * @uaddr: C string containing universal address to convert
 300  * @uaddr_len: length of universal address string
 301  * @sap: buffer into which to plant socket address
 302  * @salen: size of buffer
 303  *
 304  * @uaddr does not have to be '\0'-terminated, but kstrtou8() and
 305  * rpc_pton() require proper string termination to be successful.
 306  *
 307  * Returns the size of the socket address if successful; otherwise
 308  * zero is returned.
 309  */
 310 size_t rpc_uaddr2sockaddr(struct net *net, const char *uaddr,
 311                           const size_t uaddr_len, struct sockaddr *sap,
 312                           const size_t salen)
 313 {
 314         char *c, buf[RPCBIND_MAXUADDRLEN + sizeof('\0')];
 315         u8 portlo, porthi;
 316         unsigned short port;
 317
 318         if (uaddr_len > RPCBIND_MAXUADDRLEN)
 319                 return 0;
 320
 321         memcpy(buf, uaddr, uaddr_len);
 322
 323         buf[uaddr_len] = '\0';
 324         c = strrchr(buf, '.');
 325         if (unlikely(c == NULL))
 326                 return 0;
 327         if (unlikely(kstrtou8(c + 1, 10, &portlo) != 0))
 328                 return 0;
 329
 330         *c = '\0';
 331         c = strrchr(buf, '.');
 332         if (unlikely(c == NULL))
 333                 return 0;
 334         if (unlikely(kstrtou8(c + 1, 10, &porthi) != 0))
 335                 return 0;
 336
 337         port = (unsigned short)((porthi << 8) | portlo);
 338
 339         *c = '\0';
 340         if (rpc_pton(net, 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);