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; 166 size_t len; 167 168 if ((buf + buflen) == delim) 169 return 1; 170 171 if (*delim != IPV6_SCOPE_DELIMITER) 172 return 0; 173 174 if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)) 175 return 0; 176 177 len = (buf + buflen) - delim - 1; 178 p = kmemdup_nul(delim + 1, len, GFP_KERNEL); 179 if (p) { 180 u32 scope_id = 0; 181 struct net_device *dev; 182 183 dev = dev_get_by_name(net, p); 184 if (dev != NULL) { 185 scope_id = dev->ifindex; 186 dev_put(dev); 187 } else { 188 if (kstrtou32(p, 10, &scope_id) != 0) { 189 kfree(p); 190 return 0; 191 } 192 } 193 194 kfree(p); 195 196 sin6->sin6_scope_id = scope_id; 197 return 1; 198 } 199 200 return 0; 201 } 202 203 static size_t rpc_pton6(struct net *net, const char *buf, const size_t buflen, 204 struct sockaddr *sap, const size_t salen) 205 { 206 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap; 207 u8 *addr = (u8 *)&sin6->sin6_addr.in6_u; 208 const char *delim; 209 210 if (buflen > (INET6_ADDRSTRLEN + IPV6_SCOPE_ID_LEN) || 211 salen < sizeof(struct sockaddr_in6)) 212 return 0; 213 214 memset(sap, 0, sizeof(struct sockaddr_in6)); 215 216 if (in6_pton(buf, buflen, addr, IPV6_SCOPE_DELIMITER, &delim) == 0) 217 return 0; 218 219 if (!rpc_parse_scope_id(net, buf, buflen, delim, sin6)) 220 return 0; 221 222 sin6->sin6_family = AF_INET6; 223 return sizeof(struct sockaddr_in6); 224 } 225 #else 226 static size_t rpc_pton6(struct net *net, const char *buf, const size_t buflen, 227 struct sockaddr *sap, const size_t salen) 228 { 229 return 0; 230 } 231 #endif 232 233 /** 234 * rpc_pton - Construct a sockaddr in @sap 235 * @net: applicable network namespace 236 * @buf: C string containing presentation format IP address 237 * @buflen: length of presentation address in bytes 238 * @sap: buffer into which to plant socket address 239 * @salen: size of buffer in bytes 240 * 241 * Returns the size of the socket address if successful; otherwise 242 * zero is returned. 243 * 244 * Plants a socket address in @sap and returns the size of the 245 * socket address, if successful. Returns zero if an error 246 * occurred. 247 */ 248 size_t rpc_pton(struct net *net, const char *buf, const size_t buflen, 249 struct sockaddr *sap, const size_t salen) 250 { 251 unsigned int i; 252 253 for (i = 0; i < buflen; i++) 254 if (buf[i] == ':') 255 return rpc_pton6(net, buf, buflen, sap, salen); 256 return rpc_pton4(buf, buflen, sap, salen); 257 } 258 EXPORT_SYMBOL_GPL(rpc_pton); 259 260 /** 261 * rpc_sockaddr2uaddr - Construct a universal address string from @sap. 262 * @sap: socket address 263 * @gfp_flags: allocation mode 264 * 265 * Returns a %NUL-terminated string in dynamically allocated memory; 266 * otherwise NULL is returned if an error occurred. Caller must 267 * free the returned string. 268 */ 269 char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags) 270 { 271 char portbuf[RPCBIND_MAXUADDRPLEN]; 272 char addrbuf[RPCBIND_MAXUADDRLEN]; 273 unsigned short port; 274 275 switch (sap->sa_family) { 276 case AF_INET: 277 if (rpc_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0) 278 return NULL; 279 port = ntohs(((struct sockaddr_in *)sap)->sin_port); 280 break; 281 case AF_INET6: 282 if (rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0) 283 return NULL; 284 port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port); 285 break; 286 default: 287 return NULL; 288 } 289 290 if (snprintf(portbuf, sizeof(portbuf), 291 ".%u.%u", port >> 8, port & 0xff) > (int)sizeof(portbuf)) 292 return NULL; 293 294 if (strlcat(addrbuf, portbuf, sizeof(addrbuf)) > sizeof(addrbuf)) 295 return NULL; 296 297 return kstrdup(addrbuf, gfp_flags); 298 } 299 300 /** 301 * rpc_uaddr2sockaddr - convert a universal address to a socket address. 302 * @net: applicable network namespace 303 * @uaddr: C string containing universal address to convert 304 * @uaddr_len: length of universal address string 305 * @sap: buffer into which to plant socket address 306 * @salen: size of buffer 307 * 308 * @uaddr does not have to be '\0'-terminated, but kstrtou8() and 309 * rpc_pton() require proper string termination to be successful. 310 * 311 * Returns the size of the socket address if successful; otherwise 312 * zero is returned. 313 */ 314 size_t rpc_uaddr2sockaddr(struct net *net, const char *uaddr, 315 const size_t uaddr_len, struct sockaddr *sap, 316 const size_t salen) 317 { 318 char *c, buf[RPCBIND_MAXUADDRLEN + sizeof('\0')]; 319 u8 portlo, porthi; 320 unsigned short port; 321 322 if (uaddr_len > RPCBIND_MAXUADDRLEN) 323 return 0; 324 325 memcpy(buf, uaddr, uaddr_len); 326 327 buf[uaddr_len] = '\0'; 328 c = strrchr(buf, '.'); 329 if (unlikely(c == NULL)) 330 return 0; 331 if (unlikely(kstrtou8(c + 1, 10, &portlo) != 0)) 332 return 0; 333 334 *c = '\0'; 335 c = strrchr(buf, '.'); 336 if (unlikely(c == NULL)) 337 return 0; 338 if (unlikely(kstrtou8(c + 1, 10, &porthi) != 0)) 339 return 0; 340 341 port = (unsigned short)((porthi << 8) | portlo); 342 343 *c = '\0'; 344 if (rpc_pton(net, buf, strlen(buf), sap, salen) == 0) 345 return 0; 346 347 switch (sap->sa_family) { 348 case AF_INET: 349 ((struct sockaddr_in *)sap)->sin_port = htons(port); 350 return sizeof(struct sockaddr_in); 351 case AF_INET6: 352 ((struct sockaddr_in6 *)sap)->sin6_port = htons(port); 353 return sizeof(struct sockaddr_in6); 354 } 355 356 return 0; 357 } 358 EXPORT_SYMBOL_GPL(rpc_uaddr2sockaddr); 359