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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/addr.h>
21 #include <linux/sunrpc/msg_prot.h>
22 #include <linux/slab.h>
23 #include <linux/export.h>
24
25 #if IS_ENABLED(CONFIG_IPV6)
26
27 static size_t rpc_ntop6_noscopeid(const struct sockaddr *sap,
28 char *buf, const int buflen)
29 {
30 const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
31 const struct in6_addr *addr = &sin6->sin6_addr;
32
33 /*
34 * RFC 4291, Section 2.2.2
35 *
36 * Shorthanded ANY address
37 */
38 if (ipv6_addr_any(addr))
39 return snprintf(buf, buflen, "::");
40
41 /*
42 * RFC 4291, Section 2.2.2
43 *
44 * Shorthanded loopback address
45 */
46 if (ipv6_addr_loopback(addr))
47 return snprintf(buf, buflen, "::1");
48
49 /*
50 * RFC 4291, Section 2.2.3
51 *
52 * Special presentation address format for mapped v4
53 * addresses.
54 */
55 if (ipv6_addr_v4mapped(addr))
56 return snprintf(buf, buflen, "::ffff:%pI4",
57 &addr->s6_addr32[3]);
58
59 /*
60 * RFC 4291, Section 2.2.1
61 */
62 return snprintf(buf, buflen, "%pI6c", addr);
63 }
64
65 static size_t rpc_ntop6(const struct sockaddr *sap,
66 char *buf, const size_t buflen)
67 {
68 const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
69 char scopebuf[IPV6_SCOPE_ID_LEN];
70 size_t len;
71 int rc;
72
73 len = rpc_ntop6_noscopeid(sap, buf, buflen);
74 if (unlikely(len == 0))
75 return len;
76
77 if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
78 return len;
79 if (sin6->sin6_scope_id == 0)
80 return len;
81
82 rc = snprintf(scopebuf, sizeof(scopebuf), "%c%u",
83 IPV6_SCOPE_DELIMITER, sin6->sin6_scope_id);
84 if (unlikely((size_t)rc > sizeof(scopebuf)))
85 return 0;
86
87 len += rc;
88 if (unlikely(len > buflen))
89 return 0;
90
91 strcat(buf, scopebuf);
92 return len;
93 }
94
95 #else /* !IS_ENABLED(CONFIG_IPV6) */
96
97 static size_t rpc_ntop6_noscopeid(const struct sockaddr *sap,
98 char *buf, const int buflen)
99 {
100 return 0;
101 }
102
103 static size_t rpc_ntop6(const struct sockaddr *sap,
104 char *buf, const size_t buflen)
105 {
106 return 0;
107 }
108
109 #endif /* !IS_ENABLED(CONFIG_IPV6) */
110
111 static int rpc_ntop4(const struct sockaddr *sap,
112 char *buf, const size_t buflen)
113 {
114 const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
115
116 return snprintf(buf, buflen, "%pI4", &sin->sin_addr);
117 }
118
119 /**
120 * rpc_ntop - construct a presentation address in @buf
121 * @sap: socket address
122 * @buf: construction area
123 * @buflen: size of @buf, in bytes
124 *
125 * Plants a %NUL-terminated string in @buf and returns the length
126 * of the string, excluding the %NUL. Otherwise zero is returned.
127 */
128 size_t rpc_ntop(const struct sockaddr *sap, char *buf, const size_t buflen)
129 {
130 switch (sap->sa_family) {
131 case AF_INET:
132 return rpc_ntop4(sap, buf, buflen);
133 case AF_INET6:
134 return rpc_ntop6(sap, buf, buflen);
135 }
136
137 return 0;
138 }
139 EXPORT_SYMBOL_GPL(rpc_ntop);
140
141 static size_t rpc_pton4(const char *buf, const size_t buflen,
142 struct sockaddr *sap, const size_t salen)
143 {
144 struct sockaddr_in *sin = (struct sockaddr_in *)sap;
145 u8 *addr = (u8 *)&sin->sin_addr.s_addr;
146
147 if (buflen > INET_ADDRSTRLEN || salen < sizeof(struct sockaddr_in))
148 return 0;
149
150 memset(sap, 0, sizeof(struct sockaddr_in));
151
152 if (in4_pton(buf, buflen, addr, '\0', NULL) == 0)
153 return 0;
154
155 sin->sin_family = AF_INET;
156 return sizeof(struct sockaddr_in);
157 }
158
159 #if IS_ENABLED(CONFIG_IPV6)
160 static int rpc_parse_scope_id(struct net *net, const char *buf,
161 const size_t buflen, const char *delim,
162 struct sockaddr_in6 *sin6)
163 {
164 char *p;
165 size_t len;
166
167 if ((buf + buflen) == delim)
168 return 1;
169
170 if (*delim != IPV6_SCOPE_DELIMITER)
171 return 0;
172
173 if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
174 return 0;
175
176 len = (buf + buflen) - delim - 1;
177 p = kstrndup(delim + 1, len, GFP_KERNEL);
178 if (p) {
179 u32 scope_id = 0;
180 struct net_device *dev;
181
182 dev = dev_get_by_name(net, p);
183 if (dev != NULL) {
184 scope_id = dev->ifindex;
185 dev_put(dev);
186 } else {
187 if (kstrtou32(p, 10, &scope_id) == 0) {
188 kfree(p);
189 return 0;
190 }
191 }
192
193 kfree(p);
194
195 sin6->sin6_scope_id = scope_id;
196 return 1;
197 }
198
199 return 0;
200 }
201
202 static size_t rpc_pton6(struct net *net, const char *buf, const size_t buflen,
203 struct sockaddr *sap, const size_t salen)
204 {
205 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
206 u8 *addr = (u8 *)&sin6->sin6_addr.in6_u;
207 const char *delim;
208
209 if (buflen > (INET6_ADDRSTRLEN + IPV6_SCOPE_ID_LEN) ||
210 salen < sizeof(struct sockaddr_in6))
211 return 0;
212
213 memset(sap, 0, sizeof(struct sockaddr_in6));
214
215 if (in6_pton(buf, buflen, addr, IPV6_SCOPE_DELIMITER, &delim) == 0)
216 return 0;
217
218 if (!rpc_parse_scope_id(net, buf, buflen, delim, sin6))
219 return 0;
220
221 sin6->sin6_family = AF_INET6;
222 return sizeof(struct sockaddr_in6);
223 }
224 #else
225 static size_t rpc_pton6(struct net *net, const char *buf, const size_t buflen,
226 struct sockaddr *sap, const size_t salen)
227 {
228 return 0;
229 }
230 #endif
231
232 /**
233 * rpc_pton - Construct a sockaddr in @sap
234 * @net: applicable network namespace
235 * @buf: C string containing presentation format IP address
236 * @buflen: length of presentation address in bytes
237 * @sap: buffer into which to plant socket address
238 * @salen: size of buffer in bytes
239 *
240 * Returns the size of the socket address if successful; otherwise
241 * zero is returned.
242 *
243 * Plants a socket address in @sap and returns the size of the
244 * socket address, if successful. Returns zero if an error
245 * occurred.
246 */
247 size_t rpc_pton(struct net *net, const char *buf, const size_t buflen,
248 struct sockaddr *sap, const size_t salen)
249 {
250 unsigned int i;
251
252 for (i = 0; i < buflen; i++)
253 if (buf[i] == ':')
254 return rpc_pton6(net, buf, buflen, sap, salen);
255 return rpc_pton4(buf, buflen, sap, salen);
256 }
257 EXPORT_SYMBOL_GPL(rpc_pton);
258
259 /**
260 * rpc_sockaddr2uaddr - Construct a universal address string from @sap.
261 * @sap: socket address
262 * @gfp_flags: allocation mode
263 *
264 * Returns a %NUL-terminated string in dynamically allocated memory;
265 * otherwise NULL is returned if an error occurred. Caller must
266 * free the returned string.
267 */
268 char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)
269 {
270 char portbuf[RPCBIND_MAXUADDRPLEN];
271 char addrbuf[RPCBIND_MAXUADDRLEN];
272 unsigned short port;
273
274 switch (sap->sa_family) {
275 case AF_INET:
276 if (rpc_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
277 return NULL;
278 port = ntohs(((struct sockaddr_in *)sap)->sin_port);
279 break;
280 case AF_INET6:
281 if (rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
282 return NULL;
283 port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
284 break;
285 default:
286 return NULL;
287 }
288
289 if (snprintf(portbuf, sizeof(portbuf),
290 ".%u.%u", port >> 8, port & 0xff) > (int)sizeof(portbuf))
291 return NULL;
292
293 if (strlcat(addrbuf, portbuf, sizeof(addrbuf)) > sizeof(addrbuf))
294 return NULL;
295
296 return kstrdup(addrbuf, gfp_flags);
297 }
298
299 /**
300 * rpc_uaddr2sockaddr - convert a universal address to a socket address.
301 * @net: applicable network namespace
302 * @uaddr: C string containing universal address to convert
303 * @uaddr_len: length of universal address string
304 * @sap: buffer into which to plant socket address
305 * @salen: size of buffer
306 *
307 * @uaddr does not have to be '\0'-terminated, but kstrtou8() and
308 * rpc_pton() require proper string termination to be successful.
309 *
310 * Returns the size of the socket address if successful; otherwise
311 * zero is returned.
312 */
313 size_t rpc_uaddr2sockaddr(struct net *net, const char *uaddr,
314 const size_t uaddr_len, struct sockaddr *sap,
315 const size_t salen)
316 {
317 char *c, buf[RPCBIND_MAXUADDRLEN + sizeof('\0')];
318 u8 portlo, porthi;
319 unsigned short port;
320
321 if (uaddr_len > RPCBIND_MAXUADDRLEN)
322 return 0;
323
324 memcpy(buf, uaddr, uaddr_len);
325
326 buf[uaddr_len] = '\0';
327 c = strrchr(buf, '.');
328 if (unlikely(c == NULL))
329 return 0;
330 if (unlikely(kstrtou8(c + 1, 10, &portlo) != 0))
331 return 0;
332
333 *c = '\0';
334 c = strrchr(buf, '.');
335 if (unlikely(c == NULL))
336 return 0;
337 if (unlikely(kstrtou8(c + 1, 10, &porthi) != 0))
338 return 0;
339
340 port = (unsigned short)((porthi << 8) | portlo);
341
342 *c = '\0';
343 if (rpc_pton(net, buf, strlen(buf), sap, salen) == 0)
344 return 0;
345
346 switch (sap->sa_family) {
347 case AF_INET:
348 ((struct sockaddr_in *)sap)->sin_port = htons(port);
349 return sizeof(struct sockaddr_in);
350 case AF_INET6:
351 ((struct sockaddr_in6 *)sap)->sin6_port = htons(port);
352 return sizeof(struct sockaddr_in6);
353 }
354
355 return 0;
356 }
357 EXPORT_SYMBOL_GPL(rpc_uaddr2sockaddr);