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);
355
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