1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Generic address resultion entity
4 *
5 * Authors:
6 * net_random Alan Cox
7 * net_ratelimit Andi Kleen
8 * in{4,6}_pton YOSHIFUJI Hideaki, Copyright (C)2006 USAGI/WIDE Project
9 *
10 * Created by Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
11 */
12
13 #include <linux/module.h>
14 #include <linux/jiffies.h>
15 #include <linux/kernel.h>
16 #include <linux/ctype.h>
17 #include <linux/inet.h>
18 #include <linux/mm.h>
19 #include <linux/net.h>
20 #include <linux/string.h>
21 #include <linux/types.h>
22 #include <linux/percpu.h>
23 #include <linux/init.h>
24 #include <linux/ratelimit.h>
25 #include <linux/socket.h>
26
27 #include <net/sock.h>
28 #include <net/net_ratelimit.h>
29 #include <net/ipv6.h>
30
31 #include <asm/byteorder.h>
32 #include <linux/uaccess.h>
33
34 DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
35 /*
36 * All net warning printk()s should be guarded by this function.
37 */
38 int net_ratelimit(void)
39 {
40 return __ratelimit(&net_ratelimit_state);
41 }
42 EXPORT_SYMBOL(net_ratelimit);
43
44 /*
45 * Convert an ASCII string to binary IP.
46 * This is outside of net/ipv4/ because various code that uses IP addresses
47 * is otherwise not dependent on the TCP/IP stack.
48 */
49
50 __be32 in_aton(const char *str)
51 {
52 unsigned int l;
53 unsigned int val;
54 int i;
55
56 l = 0;
57 for (i = 0; i < 4; i++) {
58 l <<= 8;
59 if (*str != '\0') {
60 val = 0;
61 while (*str != '\0' && *str != '.' && *str != '\n') {
62 val *= 10;
63 val += *str - '';
64 str++;
65 }
66 l |= val;
67 if (*str != '\0')
68 str++;
69 }
70 }
71 return htonl(l);
72 }
73 EXPORT_SYMBOL(in_aton);
74
75 #define IN6PTON_XDIGIT 0x00010000
76 #define IN6PTON_DIGIT 0x00020000
77 #define IN6PTON_COLON_MASK 0x00700000
78 #define IN6PTON_COLON_1 0x00100000 /* single : requested */
79 #define IN6PTON_COLON_2 0x00200000 /* second : requested */
80 #define IN6PTON_COLON_1_2 0x00400000 /* :: requested */
81 #define IN6PTON_DOT 0x00800000 /* . */
82 #define IN6PTON_DELIM 0x10000000
83 #define IN6PTON_NULL 0x20000000 /* first/tail */
84 #define IN6PTON_UNKNOWN 0x40000000
85
86 static inline int xdigit2bin(char c, int delim)
87 {
88 int val;
89
90 if (c == delim || c == '\0')
91 return IN6PTON_DELIM;
92 if (c == ':')
93 return IN6PTON_COLON_MASK;
94 if (c == '.')
95 return IN6PTON_DOT;
96
97 val = hex_to_bin(c);
98 if (val >= 0)
99 return val | IN6PTON_XDIGIT | (val < 10 ? IN6PTON_DIGIT : 0);
100
101 if (delim == -1)
102 return IN6PTON_DELIM;
103 return IN6PTON_UNKNOWN;
104 }
105
106 /**
107 * in4_pton - convert an IPv4 address from literal to binary representation
108 * @src: the start of the IPv4 address string
109 * @srclen: the length of the string, -1 means strlen(src)
110 * @dst: the binary (u8[4] array) representation of the IPv4 address
111 * @delim: the delimiter of the IPv4 address in @src, -1 means no delimiter
112 * @end: A pointer to the end of the parsed string will be placed here
113 *
114 * Return one on success, return zero when any error occurs
115 * and @end will point to the end of the parsed string.
116 *
117 */
118 int in4_pton(const char *src, int srclen,
119 u8 *dst,
120 int delim, const char **end)
121 {
122 const char *s;
123 u8 *d;
124 u8 dbuf[4];
125 int ret = 0;
126 int i;
127 int w = 0;
128
129 if (srclen < 0)
130 srclen = strlen(src);
131 s = src;
132 d = dbuf;
133 i = 0;
134 while (1) {
135 int c;
136 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
137 if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
138 goto out;
139 }
140 if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
141 if (w == 0)
142 goto out;
143 *d++ = w & 0xff;
144 w = 0;
145 i++;
146 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
147 if (i != 4)
148 goto out;
149 break;
150 }
151 goto cont;
152 }
153 w = (w * 10) + c;
154 if ((w & 0xffff) > 255) {
155 goto out;
156 }
157 cont:
158 if (i >= 4)
159 goto out;
160 s++;
161 srclen--;
162 }
163 ret = 1;
164 memcpy(dst, dbuf, sizeof(dbuf));
165 out:
166 if (end)
167 *end = s;
168 return ret;
169 }
170 EXPORT_SYMBOL(in4_pton);
171
172 /**
173 * in6_pton - convert an IPv6 address from literal to binary representation
174 * @src: the start of the IPv6 address string
175 * @srclen: the length of the string, -1 means strlen(src)
176 * @dst: the binary (u8[16] array) representation of the IPv6 address
177 * @delim: the delimiter of the IPv6 address in @src, -1 means no delimiter
178 * @end: A pointer to the end of the parsed string will be placed here
179 *
180 * Return one on success, return zero when any error occurs
181 * and @end will point to the end of the parsed string.
182 *
183 */
184 int in6_pton(const char *src, int srclen,
185 u8 *dst,
186 int delim, const char **end)
187 {
188 const char *s, *tok = NULL;
189 u8 *d, *dc = NULL;
190 u8 dbuf[16];
191 int ret = 0;
192 int i;
193 int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
194 int w = 0;
195
196 memset(dbuf, 0, sizeof(dbuf));
197
198 s = src;
199 d = dbuf;
200 if (srclen < 0)
201 srclen = strlen(src);
202
203 while (1) {
204 int c;
205
206 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
207 if (!(c & state))
208 goto out;
209 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
210 /* process one 16-bit word */
211 if (!(state & IN6PTON_NULL)) {
212 *d++ = (w >> 8) & 0xff;
213 *d++ = w & 0xff;
214 }
215 w = 0;
216 if (c & IN6PTON_DELIM) {
217 /* We've processed last word */
218 break;
219 }
220 /*
221 * COLON_1 => XDIGIT
222 * COLON_2 => XDIGIT|DELIM
223 * COLON_1_2 => COLON_2
224 */
225 switch (state & IN6PTON_COLON_MASK) {
226 case IN6PTON_COLON_2:
227 dc = d;
228 state = IN6PTON_XDIGIT | IN6PTON_DELIM;
229 if (dc - dbuf >= sizeof(dbuf))
230 state |= IN6PTON_NULL;
231 break;
232 case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
233 state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
234 break;
235 case IN6PTON_COLON_1:
236 state = IN6PTON_XDIGIT;
237 break;
238 case IN6PTON_COLON_1_2:
239 state = IN6PTON_COLON_2;
240 break;
241 default:
242 state = 0;
243 }
244 tok = s + 1;
245 goto cont;
246 }
247
248 if (c & IN6PTON_DOT) {
249 ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
250 if (ret > 0) {
251 d += 4;
252 break;
253 }
254 goto out;
255 }
256
257 w = (w << 4) | (0xff & c);
258 state = IN6PTON_COLON_1 | IN6PTON_DELIM;
259 if (!(w & 0xf000)) {
260 state |= IN6PTON_XDIGIT;
261 }
262 if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
263 state |= IN6PTON_COLON_1_2;
264 state &= ~IN6PTON_DELIM;
265 }
266 if (d + 2 >= dbuf + sizeof(dbuf)) {
267 state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
268 }
269 cont:
270 if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
271 d + 4 == dbuf + sizeof(dbuf)) {
272 state |= IN6PTON_DOT;
273 }
274 if (d >= dbuf + sizeof(dbuf)) {
275 state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
276 }
277 s++;
278 srclen--;
279 }
280
281 i = 15; d--;
282
283 if (dc) {
284 while (d >= dc)
285 dst[i--] = *d--;
286 while (i >= dc - dbuf)
287 dst[i--] = 0;
288 while (i >= 0)
289 dst[i--] = *d--;
290 } else
291 memcpy(dst, dbuf, sizeof(dbuf));
292
293 ret = 1;
294 out:
295 if (end)
296 *end = s;
297 return ret;
298 }
299 EXPORT_SYMBOL(in6_pton);
300
301 static int inet4_pton(const char *src, u16 port_num,
302 struct sockaddr_storage *addr)
303 {
304 struct sockaddr_in *addr4 = (struct sockaddr_in *)addr;
305 size_t srclen = strlen(src);
306
307 if (srclen > INET_ADDRSTRLEN)
308 return -EINVAL;
309
310 if (in4_pton(src, srclen, (u8 *)&addr4->sin_addr.s_addr,
311 '\n', NULL) == 0)
312 return -EINVAL;
313
314 addr4->sin_family = AF_INET;
315 addr4->sin_port = htons(port_num);
316
317 return 0;
318 }
319
320 static int inet6_pton(struct net *net, const char *src, u16 port_num,
321 struct sockaddr_storage *addr)
322 {
323 struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)addr;
324 const char *scope_delim;
325 size_t srclen = strlen(src);
326
327 if (srclen > INET6_ADDRSTRLEN)
328 return -EINVAL;
329
330 if (in6_pton(src, srclen, (u8 *)&addr6->sin6_addr.s6_addr,
331 '%', &scope_delim) == 0)
332 return -EINVAL;
333
334 if (ipv6_addr_type(&addr6->sin6_addr) & IPV6_ADDR_LINKLOCAL &&
335 src + srclen != scope_delim && *scope_delim == '%') {
336 struct net_device *dev;
337 char scope_id[16];
338 size_t scope_len = min_t(size_t, sizeof(scope_id) - 1,
339 src + srclen - scope_delim - 1);
340
341 memcpy(scope_id, scope_delim + 1, scope_len);
342 scope_id[scope_len] = '\0';
343
344 dev = dev_get_by_name(net, scope_id);
345 if (dev) {
346 addr6->sin6_scope_id = dev->ifindex;
347 dev_put(dev);
348 } else if (kstrtouint(scope_id, 0, &addr6->sin6_scope_id)) {
349 return -EINVAL;
350 }
351 }
352
353 addr6->sin6_family = AF_INET6;
354 addr6->sin6_port = htons(port_num);
355
356 return 0;
357 }
358
359 /**
360 * inet_pton_with_scope - convert an IPv4/IPv6 and port to socket address
361 * @net: net namespace (used for scope handling)
362 * @af: address family, AF_INET, AF_INET6 or AF_UNSPEC for either
363 * @src: the start of the address string
364 * @port: the start of the port string (or NULL for none)
365 * @addr: output socket address
366 *
367 * Return zero on success, return errno when any error occurs.
368 */
369 int inet_pton_with_scope(struct net *net, __kernel_sa_family_t af,
370 const char *src, const char *port, struct sockaddr_storage *addr)
371 {
372 u16 port_num;
373 int ret = -EINVAL;
374
375 if (port) {
376 if (kstrtou16(port, 0, &port_num))
377 return -EINVAL;
378 } else {
379 port_num = 0;
380 }
381
382 switch (af) {
383 case AF_INET:
384 ret = inet4_pton(src, port_num, addr);
385 break;
386 case AF_INET6:
387 ret = inet6_pton(net, src, port_num, addr);
388 break;
389 case AF_UNSPEC:
390 ret = inet4_pton(src, port_num, addr);
391 if (ret)
392 ret = inet6_pton(net, src, port_num, addr);
393 break;
394 default:
395 pr_err("unexpected address family %d\n", af);
396 }
397
398 return ret;
399 }
400 EXPORT_SYMBOL(inet_pton_with_scope);
401
402 bool inet_addr_is_any(struct sockaddr *addr)
403 {
404 if (addr->sa_family == AF_INET6) {
405 struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)addr;
406 const struct sockaddr_in6 in6_any =
407 { .sin6_addr = IN6ADDR_ANY_INIT };
408
409 if (!memcmp(in6->sin6_addr.s6_addr,
410 in6_any.sin6_addr.s6_addr, 16))
411 return true;
412 } else if (addr->sa_family == AF_INET) {
413 struct sockaddr_in *in = (struct sockaddr_in *)addr;
414
415 if (in->sin_addr.s_addr == htonl(INADDR_ANY))
416 return true;
417 } else {
418 pr_warn("unexpected address family %u\n", addr->sa_family);
419 }
420
421 return false;
422 }
423 EXPORT_SYMBOL(inet_addr_is_any);
424
425 void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
426 __be32 from, __be32 to, bool pseudohdr)
427 {
428 if (skb->ip_summed != CHECKSUM_PARTIAL) {
429 csum_replace4(sum, from, to);
430 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
431 skb->csum = ~csum_add(csum_sub(~(skb->csum),
432 (__force __wsum)from),
433 (__force __wsum)to);
434 } else if (pseudohdr)
435 *sum = ~csum_fold(csum_add(csum_sub(csum_unfold(*sum),
436 (__force __wsum)from),
437 (__force __wsum)to));
438 }
439 EXPORT_SYMBOL(inet_proto_csum_replace4);
440
441 /**
442 * inet_proto_csum_replace16 - update layer 4 header checksum field
443 * @sum: Layer 4 header checksum field
444 * @skb: sk_buff for the packet
445 * @from: old IPv6 address
446 * @to: new IPv6 address
447 * @pseudohdr: True if layer 4 header checksum includes pseudoheader
448 *
449 * Update layer 4 header as per the update in IPv6 src/dst address.
450 *
451 * There is no need to update skb->csum in this function, because update in two
452 * fields a.) IPv6 src/dst address and b.) L4 header checksum cancels each other
453 * for skb->csum calculation. Whereas inet_proto_csum_replace4 function needs to
454 * update skb->csum, because update in 3 fields a.) IPv4 src/dst address,
455 * b.) IPv4 Header checksum and c.) L4 header checksum results in same diff as
456 * L4 Header checksum for skb->csum calculation.
457 */
458 void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
459 const __be32 *from, const __be32 *to,
460 bool pseudohdr)
461 {
462 __be32 diff[] = {
463 ~from[0], ~from[1], ~from[2], ~from[3],
464 to[0], to[1], to[2], to[3],
465 };
466 if (skb->ip_summed != CHECKSUM_PARTIAL) {
467 *sum = csum_fold(csum_partial(diff, sizeof(diff),
468 ~csum_unfold(*sum)));
469 } else if (pseudohdr)
470 *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
471 csum_unfold(*sum)));
472 }
473 EXPORT_SYMBOL(inet_proto_csum_replace16);
474
475 void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
476 __wsum diff, bool pseudohdr)
477 {
478 if (skb->ip_summed != CHECKSUM_PARTIAL) {
479 csum_replace_by_diff(sum, diff);
480 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
481 skb->csum = ~csum_sub(diff, skb->csum);
482 } else if (pseudohdr) {
483 *sum = ~csum_fold(csum_add(diff, csum_unfold(*sum)));
484 }
485 }
486 EXPORT_SYMBOL(inet_proto_csum_replace_by_diff);
487
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