[deliverable/linux.git] / net / core / utils.c

/*
 *	Generic address resultion entity
 *
 *	Authors:
 *	net_random Alan Cox
 *	net_ratelimit Andi Kleen
 *	in{4,6}_pton YOSHIFUJI Hideaki, Copyright (C)2006 USAGI/WIDE Project
 *
 *	Created by Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
 *
 *	This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/ctype.h>
#include <linux/inet.h>
#include <linux/mm.h>
#include <linux/net.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/ratelimit.h>

#include <net/sock.h>
#include <net/net_ratelimit.h>

#include <asm/byteorder.h>
#include <asm/uaccess.h>

DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
/*
 * All net warning printk()s should be guarded by this function.
 */
int net_ratelimit(void)
{
	return __ratelimit(&net_ratelimit_state);
}
EXPORT_SYMBOL(net_ratelimit);

/*
 * Convert an ASCII string to binary IP.
 * This is outside of net/ipv4/ because various code that uses IP addresses
 * is otherwise not dependent on the TCP/IP stack.
 */

__be32 in_aton(const char *str)
{
	unsigned long l;
	unsigned int val;
	int i;

	l = 0;
	for (i = 0; i < 4; i++)	{
		l <<= 8;
		if (*str != '\0') {
			val = 0;
			while (*str != '\0' && *str != '.' && *str != '\n') {
				val *= 10;
				val += *str - '0';
				str++;
			}
			l |= val;
			if (*str != '\0')
				str++;
		}
	}
	return htonl(l);
}
EXPORT_SYMBOL(in_aton);

#define IN6PTON_XDIGIT		0x00010000
#define IN6PTON_DIGIT		0x00020000
#define IN6PTON_COLON_MASK	0x00700000
#define IN6PTON_COLON_1		0x00100000	/* single : requested */
#define IN6PTON_COLON_2		0x00200000	/* second : requested */
#define IN6PTON_COLON_1_2	0x00400000	/* :: requested */
#define IN6PTON_DOT		0x00800000	/* . */
#define IN6PTON_DELIM		0x10000000
#define IN6PTON_NULL		0x20000000	/* first/tail */
#define IN6PTON_UNKNOWN		0x40000000

static inline int xdigit2bin(char c, int delim)
{
	int val;

	if (c == delim || c == '\0')
		return IN6PTON_DELIM;
	if (c == ':')
		return IN6PTON_COLON_MASK;
	if (c == '.')
		return IN6PTON_DOT;

	val = hex_to_bin(c);
	if (val >= 0)
		return val | IN6PTON_XDIGIT | (val < 10 ? IN6PTON_DIGIT : 0);

	if (delim == -1)
		return IN6PTON_DELIM;
	return IN6PTON_UNKNOWN;
}

/**
 * in4_pton - convert an IPv4 address from literal to binary representation
 * @src: the start of the IPv4 address string
 * @srclen: the length of the string, -1 means strlen(src)
 * @dst: the binary (u8[4] array) representation of the IPv4 address
 * @delim: the delimiter of the IPv4 address in @src, -1 means no delimiter
 * @end: A pointer to the end of the parsed string will be placed here
 *
 * Return one on success, return zero when any error occurs
 * and @end will point to the end of the parsed string.
 *
 */
int in4_pton(const char *src, int srclen,
	     u8 *dst,
	     int delim, const char **end)
{
	const char *s;
	u8 *d;
	u8 dbuf[4];
	int ret = 0;
	int i;
	int w = 0;

	if (srclen < 0)
		srclen = strlen(src);
	s = src;
	d = dbuf;
	i = 0;
	while(1) {
		int c;
		c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
		if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
			goto out;
		}
		if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
			if (w == 0)
				goto out;
			*d++ = w & 0xff;
			w = 0;
			i++;
			if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
				if (i != 4)
					goto out;
				break;
			}
			goto cont;
		}
		w = (w * 10) + c;
		if ((w & 0xffff) > 255) {
			goto out;
		}
cont:
		if (i >= 4)
			goto out;
		s++;
		srclen--;
	}
	ret = 1;
	memcpy(dst, dbuf, sizeof(dbuf));
out:
	if (end)
		*end = s;
	return ret;
}
EXPORT_SYMBOL(in4_pton);

/**
 * in6_pton - convert an IPv6 address from literal to binary representation
 * @src: the start of the IPv6 address string
 * @srclen: the length of the string, -1 means strlen(src)
 * @dst: the binary (u8[16] array) representation of the IPv6 address
 * @delim: the delimiter of the IPv6 address in @src, -1 means no delimiter
 * @end: A pointer to the end of the parsed string will be placed here
 *
 * Return one on success, return zero when any error occurs
 * and @end will point to the end of the parsed string.
 *
 */
int in6_pton(const char *src, int srclen,
	     u8 *dst,
	     int delim, const char **end)
{
	const char *s, *tok = NULL;
	u8 *d, *dc = NULL;
	u8 dbuf[16];
	int ret = 0;
	int i;
	int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
	int w = 0;

	memset(dbuf, 0, sizeof(dbuf));

	s = src;
	d = dbuf;
	if (srclen < 0)
		srclen = strlen(src);

	while (1) {
		int c;

		c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
		if (!(c & state))
			goto out;
		if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
			/* process one 16-bit word */
			if (!(state & IN6PTON_NULL)) {
				*d++ = (w >> 8) & 0xff;
				*d++ = w & 0xff;
			}
			w = 0;
			if (c & IN6PTON_DELIM) {
				/* We've processed last word */
				break;
			}
			/*
			 * COLON_1 => XDIGIT
			 * COLON_2 => XDIGIT|DELIM
			 * COLON_1_2 => COLON_2
			 */
			switch (state & IN6PTON_COLON_MASK) {
			case IN6PTON_COLON_2:
				dc = d;
				state = IN6PTON_XDIGIT | IN6PTON_DELIM;
				if (dc - dbuf >= sizeof(dbuf))
					state |= IN6PTON_NULL;
				break;
			case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
				state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
				break;
			case IN6PTON_COLON_1:
				state = IN6PTON_XDIGIT;
				break;
			case IN6PTON_COLON_1_2:
				state = IN6PTON_COLON_2;
				break;
			default:
				state = 0;
			}
			tok = s + 1;
			goto cont;
		}

		if (c & IN6PTON_DOT) {
			ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
			if (ret > 0) {
				d += 4;
				break;
			}
			goto out;
		}

		w = (w << 4) | (0xff & c);
		state = IN6PTON_COLON_1 | IN6PTON_DELIM;
		if (!(w & 0xf000)) {
			state |= IN6PTON_XDIGIT;
		}
		if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
			state |= IN6PTON_COLON_1_2;
			state &= ~IN6PTON_DELIM;
		}
		if (d + 2 >= dbuf + sizeof(dbuf)) {
			state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
		}
cont:
		if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
		    d + 4 == dbuf + sizeof(dbuf)) {
			state |= IN6PTON_DOT;
		}
		if (d >= dbuf + sizeof(dbuf)) {
			state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
		}
		s++;
		srclen--;
	}

	i = 15; d--;

	if (dc) {
		while(d >= dc)
			dst[i--] = *d--;
		while(i >= dc - dbuf)
			dst[i--] = 0;
		while(i >= 0)
			dst[i--] = *d--;
	} else
		memcpy(dst, dbuf, sizeof(dbuf));

	ret = 1;
out:
	if (end)
		*end = s;
	return ret;
}
EXPORT_SYMBOL(in6_pton);

void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
			      __be32 from, __be32 to, int pseudohdr)
{
	if (skb->ip_summed != CHECKSUM_PARTIAL) {
		*sum = csum_fold(csum_add(csum_sub(~csum_unfold(*sum), from),
				 to));
		if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
			skb->csum = ~csum_add(csum_sub(~(skb->csum), from), to);
	} else if (pseudohdr)
		*sum = ~csum_fold(csum_add(csum_sub(csum_unfold(*sum), from),
				  to));
}
EXPORT_SYMBOL(inet_proto_csum_replace4);

void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
			       const __be32 *from, const __be32 *to,
			       int pseudohdr)
{
	__be32 diff[] = {
		~from[0], ~from[1], ~from[2], ~from[3],
		to[0], to[1], to[2], to[3],
	};
	if (skb->ip_summed != CHECKSUM_PARTIAL) {
		*sum = csum_fold(csum_partial(diff, sizeof(diff),
				 ~csum_unfold(*sum)));
		if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
			skb->csum = ~csum_partial(diff, sizeof(diff),
						  ~skb->csum);
	} else if (pseudohdr)
		*sum = ~csum_fold(csum_partial(diff, sizeof(diff),
				  csum_unfold(*sum)));
}
EXPORT_SYMBOL(inet_proto_csum_replace16);

struct __net_random_once_work {
	struct work_struct work;
	struct static_key *key;
};

static void __net_random_once_deferred(struct work_struct *w)
{
	struct __net_random_once_work *work =
		container_of(w, struct __net_random_once_work, work);
	BUG_ON(!static_key_enabled(work->key));
	static_key_slow_dec(work->key);
	kfree(work);
}

static void __net_random_once_disable_jump(struct static_key *key)
{
	struct __net_random_once_work *w;

	w = kmalloc(sizeof(*w), GFP_ATOMIC);
	if (!w)
		return;

	INIT_WORK(&w->work, __net_random_once_deferred);
	w->key = key;
	schedule_work(&w->work);
}

bool __net_get_random_once(void *buf, int nbytes, bool *done,
			   struct static_key *once_key)
{
	static DEFINE_SPINLOCK(lock);
	unsigned long flags;

	spin_lock_irqsave(&lock, flags);
	if (*done) {
		spin_unlock_irqrestore(&lock, flags);
		return false;
	}

	get_random_bytes(buf, nbytes);
	*done = true;
	spin_unlock_irqrestore(&lock, flags);

	__net_random_once_disable_jump(once_key);

	return true;
}
EXPORT_SYMBOL(__net_get_random_once);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Generic address resultion entity
	3	*
	4	* Authors:
	5	* net_random Alan Cox
75b31c33	6	* net_ratelimit Andi Kleen
1aaec67f	7	* in{4,6}_pton YOSHIFUJI Hideaki, Copyright (C)2006 USAGI/WIDE Project
1da177e4 LT	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>
5a048e3b	20	#include <linux/ctype.h>
20380731	21	#include <linux/inet.h>
1da177e4	22	#include <linux/mm.h>
20380731	23	#include <linux/net.h>
1da177e4 LT	24	#include <linux/string.h>
1da177e4 LT	25	#include <linux/types.h>
1da177e4 LT	26	#include <linux/percpu.h>
1da177e4 LT	27	#include <linux/init.h>
3fff4c42 IM	28	#include <linux/ratelimit.h>
3fff4c42 IM	29
14ae8566	30	#include <net/sock.h>
c5c177b4	31	#include <net/net_ratelimit.h>
1da177e4	32
5e43db77	33	#include <asm/byteorder.h>
1da177e4 LT	34	#include <asm/uaccess.h>
1da177e4 LT	35
717115e1	36	DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
4ec93edb	37	/*
1da177e4	38	* All net warning printk()s should be guarded by this function.
4ec93edb	39	*/
1da177e4 LT	40	int net_ratelimit(void)
1da177e4 LT	41	{
717115e1	42	return __ratelimit(&net_ratelimit_state);
1da177e4	43	}
1da177e4	44	EXPORT_SYMBOL(net_ratelimit);
5e43db77 MM	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
a2167dc6	52	__be32 in_aton(const char *str)
5e43db77 MM	53	{
	54	unsigned long l;
	55	unsigned int val;
	56	int i;
	57
	58	l = 0;
46ba5b23	59	for (i = 0; i < 4; i++) {
5e43db77	60	l <<= 8;
46ba5b23	61	if (*str != '\0') {
5e43db77	62	val = 0;
46ba5b23	63	while (str != '\0' && str != '.' && *str != '\n') {
5e43db77 MM	64	val *= 10;
	65	val += *str - '0';
	66	str++;
	67	}
	68	l \|= val;
	69	if (*str != '\0')
	70	str++;
	71	}
	72	}
a02cec21	73	return htonl(l);
5e43db77	74	}
5e43db77	75	EXPORT_SYMBOL(in_aton);
1aaec67f YH	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
9a7c9337	88	static inline int xdigit2bin(char c, int delim)
1aaec67f	89	{
82fd5b5d AS	90	int val;
82fd5b5d AS	91
1aaec67f YH	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;
82fd5b5d AS	98
	99	val = hex_to_bin(c);
	100	if (val >= 0)
	101	return val \| IN6PTON_XDIGIT \| (val < 10 ? IN6PTON_DIGIT : 0);
	102
9a7c9337 PM	103	if (delim == -1)
9a7c9337 PM	104	return IN6PTON_DELIM;
1aaec67f YH	105	return IN6PTON_UNKNOWN;
	106	}
	107
93ac0ef0 AW	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	*/
1aaec67f YH	120	int in4_pton(const char *src, int srclen,
1aaec67f YH	121	u8 *dst,
9a7c9337	122	int delim, const char **end)
1aaec67f YH	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);
83f03fa5	139	if (!(c & (IN6PTON_DIGIT \| IN6PTON_DOT \| IN6PTON_DELIM \| IN6PTON_COLON_MASK))) {
1aaec67f YH	140	goto out;
1aaec67f YH	141	}
83f03fa5	142	if (c & (IN6PTON_DOT \| IN6PTON_DELIM \| IN6PTON_COLON_MASK)) {
1aaec67f YH	143	if (w == 0)
	144	goto out;
	145	*d++ = w & 0xff;
	146	w = 0;
	147	i++;
83f03fa5	148	if (c & (IN6PTON_DELIM \| IN6PTON_COLON_MASK)) {
1aaec67f YH	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	}
	159	cont:
	160	if (i >= 4)
	161	goto out;
	162	s++;
	163	srclen--;
	164	}
	165	ret = 1;
	166	memcpy(dst, dbuf, sizeof(dbuf));
	167	out:
	168	if (end)
	169	*end = s;
	170	return ret;
	171	}
1aaec67f YH	172	EXPORT_SYMBOL(in4_pton);
1aaec67f YH	173
28194fcd AW	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	*/
1aaec67f YH	186	int in6_pton(const char *src, int srclen,
1aaec67f YH	187	u8 *dst,
9a7c9337	188	int delim, const char **end)
1aaec67f YH	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
1aaec67f YH	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	}
271	cont:
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;
296	out:
297	if (end)
298	*end = s;
299	return ret;
300	}
1aaec67f	301	EXPORT_SYMBOL(in6_pton);
a99a00cf PM	302
	303	void inet_proto_csum_replace4(__sum16 sum, struct sk_buff skb,
	304	__be32 from, __be32 to, int pseudohdr)
	305	{
a99a00cf	306	if (skb->ip_summed != CHECKSUM_PARTIAL) {
58e3cac5 LC	307	sum = csum_fold(csum_add(csum_sub(~csum_unfold(sum), from),
58e3cac5 LC	308	to));
a99a00cf	309	if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
58e3cac5	310	skb->csum = ~csum_add(csum_sub(~(skb->csum), from), to);
a99a00cf	311	} else if (pseudohdr)
58e3cac5 LC	312	sum = ~csum_fold(csum_add(csum_sub(csum_unfold(sum), from),
58e3cac5 LC	313	to));
a99a00cf PM	314	}
a99a00cf PM	315	EXPORT_SYMBOL(inet_proto_csum_replace4);
4940fc88	316
2cf545e8 PM	317	void 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	}
	335	EXPORT_SYMBOL(inet_proto_csum_replace16);
a48e4292 HFS	336
	337	struct __net_random_once_work {
	338	struct work_struct work;
	339	struct static_key *key;
	340	};
	341
	342	static 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);
3d440522 HFS	346	BUG_ON(!static_key_enabled(work->key));
3d440522 HFS	347	static_key_slow_dec(work->key);
a48e4292 HFS	348	kfree(work);
	349	}
	350
	351	static 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
	364	bool __net_get_random_once(void buf, int nbytes, bool done,
3d440522	365	struct static_key *once_key)
a48e4292 HFS	366	{
a48e4292 HFS	367	static DEFINE_SPINLOCK(lock);
f84be2bd	368	unsigned long flags;
a48e4292	369
f84be2bd	370	spin_lock_irqsave(&lock, flags);
a48e4292	371	if (*done) {
f84be2bd	372	spin_unlock_irqrestore(&lock, flags);
a48e4292 HFS	373	return false;
	374	}
	375
	376	get_random_bytes(buf, nbytes);
	377	*done = true;
f84be2bd	378	spin_unlock_irqrestore(&lock, flags);
a48e4292	379
3d440522	380	__net_random_once_disable_jump(once_key);
a48e4292 HFS	381
	382	return true;
	383	}
	384	EXPORT_SYMBOL(__net_get_random_once);