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
34DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
35/*
36 * All net warning printk()s should be guarded by this function.
37 */
38int net_ratelimit(void)
39{
40	return __ratelimit(&net_ratelimit_state);
41}
42EXPORT_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 - '0';
64				str++;
65			}
66			l |= val;
67			if (*str != '\0')
68				str++;
69		}
70	}
71	return htonl(l);
72}
73EXPORT_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
86static 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 */
118int 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		}
157cont:
158		if (i >= 4)
159			goto out;
160		s++;
161		srclen--;
162	}
163	ret = 1;
164	memcpy(dst, dbuf, sizeof(dbuf));
165out:
166	if (end)
167		*end = s;
168	return ret;
169}
170EXPORT_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 */
184int 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		}
269cont:
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;
294out:
295	if (end)
296		*end = s;
297	return ret;
298}
299EXPORT_SYMBOL(in6_pton);
300
301static 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
320static 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 */
369int 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}
400EXPORT_SYMBOL(inet_pton_with_scope);
401
402bool 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}
423EXPORT_SYMBOL(inet_addr_is_any);
424
425void 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}
439EXPORT_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 */
458void 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}
473EXPORT_SYMBOL(inet_proto_csum_replace16);
474
475void 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}
486EXPORT_SYMBOL(inet_proto_csum_replace_by_diff);
487