1/*
2 *	Generic address resultion entity
3 *
4 *	Authors:
5 *	net_random Alan Cox
6 *	net_ratelimit Andi Kleen
7 *	in{4,6}_pton YOSHIFUJI Hideaki, Copyright (C)2006 USAGI/WIDE Project
8 *
9 *	Created by Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
10 *
11 *	This program is free software; you can redistribute it and/or
12 *      modify it under the terms of the GNU General Public License
13 *      as published by the Free Software Foundation; either version
14 *      2 of the License, or (at your option) any later version.
15 */
16
17#include <linux/module.h>
18#include <linux/jiffies.h>
19#include <linux/kernel.h>
20#include <linux/ctype.h>
21#include <linux/inet.h>
22#include <linux/mm.h>
23#include <linux/net.h>
24#include <linux/string.h>
25#include <linux/types.h>
26#include <linux/percpu.h>
27#include <linux/init.h>
28#include <linux/ratelimit.h>
29
30#include <net/sock.h>
31#include <net/net_ratelimit.h>
32
33#include <asm/byteorder.h>
34#include <asm/uaccess.h>
35
36DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
37/*
38 * All net warning printk()s should be guarded by this function.
39 */
40int net_ratelimit(void)
41{
42	return __ratelimit(&net_ratelimit_state);
43}
44EXPORT_SYMBOL(net_ratelimit);
45
46/*
47 * Convert an ASCII string to binary IP.
48 * This is outside of net/ipv4/ because various code that uses IP addresses
49 * is otherwise not dependent on the TCP/IP stack.
50 */
51
52__be32 in_aton(const char *str)
53{
54	unsigned long l;
55	unsigned int val;
56	int i;
57
58	l = 0;
59	for (i = 0; i < 4; i++)	{
60		l <<= 8;
61		if (*str != '\0') {
62			val = 0;
63			while (*str != '\0' && *str != '.' && *str != '\n') {
64				val *= 10;
65				val += *str - '0';
66				str++;
67			}
68			l |= val;
69			if (*str != '\0')
70				str++;
71		}
72	}
73	return htonl(l);
74}
75EXPORT_SYMBOL(in_aton);
76
77#define IN6PTON_XDIGIT		0x00010000
78#define IN6PTON_DIGIT		0x00020000
79#define IN6PTON_COLON_MASK	0x00700000
80#define IN6PTON_COLON_1		0x00100000	/* single : requested */
81#define IN6PTON_COLON_2		0x00200000	/* second : requested */
82#define IN6PTON_COLON_1_2	0x00400000	/* :: requested */
83#define IN6PTON_DOT		0x00800000	/* . */
84#define IN6PTON_DELIM		0x10000000
85#define IN6PTON_NULL		0x20000000	/* first/tail */
86#define IN6PTON_UNKNOWN		0x40000000
87
88static inline int xdigit2bin(char c, int delim)
89{
90	int val;
91
92	if (c == delim || c == '\0')
93		return IN6PTON_DELIM;
94	if (c == ':')
95		return IN6PTON_COLON_MASK;
96	if (c == '.')
97		return IN6PTON_DOT;
98
99	val = hex_to_bin(c);
100	if (val >= 0)
101		return val | IN6PTON_XDIGIT | (val < 10 ? IN6PTON_DIGIT : 0);
102
103	if (delim == -1)
104		return IN6PTON_DELIM;
105	return IN6PTON_UNKNOWN;
106}
107
108/**
109 * in4_pton - convert an IPv4 address from literal to binary representation
110 * @src: the start of the IPv4 address string
111 * @srclen: the length of the string, -1 means strlen(src)
112 * @dst: the binary (u8[4] array) representation of the IPv4 address
113 * @delim: the delimiter of the IPv4 address in @src, -1 means no delimiter
114 * @end: A pointer to the end of the parsed string will be placed here
115 *
116 * Return one on success, return zero when any error occurs
117 * and @end will point to the end of the parsed string.
118 *
119 */
120int in4_pton(const char *src, int srclen,
121	     u8 *dst,
122	     int delim, const char **end)
123{
124	const char *s;
125	u8 *d;
126	u8 dbuf[4];
127	int ret = 0;
128	int i;
129	int w = 0;
130
131	if (srclen < 0)
132		srclen = strlen(src);
133	s = src;
134	d = dbuf;
135	i = 0;
136	while(1) {
137		int c;
138		c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
139		if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
140			goto out;
141		}
142		if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
143			if (w == 0)
144				goto out;
145			*d++ = w & 0xff;
146			w = 0;
147			i++;
148			if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
149				if (i != 4)
150					goto out;
151				break;
152			}
153			goto cont;
154		}
155		w = (w * 10) + c;
156		if ((w & 0xffff) > 255) {
157			goto out;
158		}
159cont:
160		if (i >= 4)
161			goto out;
162		s++;
163		srclen--;
164	}
165	ret = 1;
166	memcpy(dst, dbuf, sizeof(dbuf));
167out:
168	if (end)
169		*end = s;
170	return ret;
171}
172EXPORT_SYMBOL(in4_pton);
173
174/**
175 * in6_pton - convert an IPv6 address from literal to binary representation
176 * @src: the start of the IPv6 address string
177 * @srclen: the length of the string, -1 means strlen(src)
178 * @dst: the binary (u8[16] array) representation of the IPv6 address
179 * @delim: the delimiter of the IPv6 address in @src, -1 means no delimiter
180 * @end: A pointer to the end of the parsed string will be placed here
181 *
182 * Return one on success, return zero when any error occurs
183 * and @end will point to the end of the parsed string.
184 *
185 */
186int in6_pton(const char *src, int srclen,
187	     u8 *dst,
188	     int delim, const char **end)
189{
190	const char *s, *tok = NULL;
191	u8 *d, *dc = NULL;
192	u8 dbuf[16];
193	int ret = 0;
194	int i;
195	int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
196	int w = 0;
197
198	memset(dbuf, 0, sizeof(dbuf));
199
200	s = src;
201	d = dbuf;
202	if (srclen < 0)
203		srclen = strlen(src);
204
205	while (1) {
206		int c;
207
208		c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
209		if (!(c & state))
210			goto out;
211		if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
212			/* process one 16-bit word */
213			if (!(state & IN6PTON_NULL)) {
214				*d++ = (w >> 8) & 0xff;
215				*d++ = w & 0xff;
216			}
217			w = 0;
218			if (c & IN6PTON_DELIM) {
219				/* We've processed last word */
220				break;
221			}
222			/*
223			 * COLON_1 => XDIGIT
224			 * COLON_2 => XDIGIT|DELIM
225			 * COLON_1_2 => COLON_2
226			 */
227			switch (state & IN6PTON_COLON_MASK) {
228			case IN6PTON_COLON_2:
229				dc = d;
230				state = IN6PTON_XDIGIT | IN6PTON_DELIM;
231				if (dc - dbuf >= sizeof(dbuf))
232					state |= IN6PTON_NULL;
233				break;
234			case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
235				state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
236				break;
237			case IN6PTON_COLON_1:
238				state = IN6PTON_XDIGIT;
239				break;
240			case IN6PTON_COLON_1_2:
241				state = IN6PTON_COLON_2;
242				break;
243			default:
244				state = 0;
245			}
246			tok = s + 1;
247			goto cont;
248		}
249
250		if (c & IN6PTON_DOT) {
251			ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
252			if (ret > 0) {
253				d += 4;
254				break;
255			}
256			goto out;
257		}
258
259		w = (w << 4) | (0xff & c);
260		state = IN6PTON_COLON_1 | IN6PTON_DELIM;
261		if (!(w & 0xf000)) {
262			state |= IN6PTON_XDIGIT;
263		}
264		if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
265			state |= IN6PTON_COLON_1_2;
266			state &= ~IN6PTON_DELIM;
267		}
268		if (d + 2 >= dbuf + sizeof(dbuf)) {
269			state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
270		}
271cont:
272		if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
273		    d + 4 == dbuf + sizeof(dbuf)) {
274			state |= IN6PTON_DOT;
275		}
276		if (d >= dbuf + sizeof(dbuf)) {
277			state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
278		}
279		s++;
280		srclen--;
281	}
282
283	i = 15; d--;
284
285	if (dc) {
286		while(d >= dc)
287			dst[i--] = *d--;
288		while(i >= dc - dbuf)
289			dst[i--] = 0;
290		while(i >= 0)
291			dst[i--] = *d--;
292	} else
293		memcpy(dst, dbuf, sizeof(dbuf));
294
295	ret = 1;
296out:
297	if (end)
298		*end = s;
299	return ret;
300}
301EXPORT_SYMBOL(in6_pton);
302
303void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
304			      __be32 from, __be32 to, int pseudohdr)
305{
306	if (skb->ip_summed != CHECKSUM_PARTIAL) {
307		*sum = csum_fold(csum_add(csum_sub(~csum_unfold(*sum), from),
308				 to));
309		if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
310			skb->csum = ~csum_add(csum_sub(~(skb->csum), from), to);
311	} else if (pseudohdr)
312		*sum = ~csum_fold(csum_add(csum_sub(csum_unfold(*sum), from),
313				  to));
314}
315EXPORT_SYMBOL(inet_proto_csum_replace4);
316
317void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
318			       const __be32 *from, const __be32 *to,
319			       int pseudohdr)
320{
321	__be32 diff[] = {
322		~from[0], ~from[1], ~from[2], ~from[3],
323		to[0], to[1], to[2], to[3],
324	};
325	if (skb->ip_summed != CHECKSUM_PARTIAL) {
326		*sum = csum_fold(csum_partial(diff, sizeof(diff),
327				 ~csum_unfold(*sum)));
328		if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
329			skb->csum = ~csum_partial(diff, sizeof(diff),
330						  ~skb->csum);
331	} else if (pseudohdr)
332		*sum = ~csum_fold(csum_partial(diff, sizeof(diff),
333				  csum_unfold(*sum)));
334}
335EXPORT_SYMBOL(inet_proto_csum_replace16);
336
337struct __net_random_once_work {
338	struct work_struct work;
339	struct static_key *key;
340};
341
342static void __net_random_once_deferred(struct work_struct *w)
343{
344	struct __net_random_once_work *work =
345		container_of(w, struct __net_random_once_work, work);
346	BUG_ON(!static_key_enabled(work->key));
347	static_key_slow_dec(work->key);
348	kfree(work);
349}
350
351static void __net_random_once_disable_jump(struct static_key *key)
352{
353	struct __net_random_once_work *w;
354
355	w = kmalloc(sizeof(*w), GFP_ATOMIC);
356	if (!w)
357		return;
358
359	INIT_WORK(&w->work, __net_random_once_deferred);
360	w->key = key;
361	schedule_work(&w->work);
362}
363
364bool __net_get_random_once(void *buf, int nbytes, bool *done,
365			   struct static_key *once_key)
366{
367	static DEFINE_SPINLOCK(lock);
368	unsigned long flags;
369
370	spin_lock_irqsave(&lock, flags);
371	if (*done) {
372		spin_unlock_irqrestore(&lock, flags);
373		return false;
374	}
375
376	get_random_bytes(buf, nbytes);
377	*done = true;
378	spin_unlock_irqrestore(&lock, flags);
379
380	__net_random_once_disable_jump(once_key);
381
382	return true;
383}
384EXPORT_SYMBOL(__net_get_random_once);
385