net/core/utils.c - linux/kernel/git/klassert/ipsec-next - Git at Google

 /*
  *	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/inet.h>
 #include <linux/mm.h>
 #include <linux/net.h>
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/random.h>
 #include <linux/percpu.h>
 #include <linux/init.h>

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

 /*
   This is a maximally equidistributed combined Tausworthe generator
   based on code from GNU Scientific Library 1.5 (30 Jun 2004)

    x_n = (s1_n ^ s2_n ^ s3_n)

    s1_{n+1} = (((s1_n & 4294967294) <<12) ^ (((s1_n <<13) ^ s1_n) >>19))
    s2_{n+1} = (((s2_n & 4294967288) << 4) ^ (((s2_n << 2) ^ s2_n) >>25))
    s3_{n+1} = (((s3_n & 4294967280) <<17) ^ (((s3_n << 3) ^ s3_n) >>11))

    The period of this generator is about 2^88.

    From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
    Generators", Mathematics of Computation, 65, 213 (1996), 203--213.

    This is available on the net from L'Ecuyer's home page,

    http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
    ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps

    There is an erratum in the paper "Tables of Maximally
    Equidistributed Combined LFSR Generators", Mathematics of
    Computation, 68, 225 (1999), 261--269:
    http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps

         ... the k_j most significant bits of z_j must be non-
         zero, for each j. (Note: this restriction also applies to the
         computer code given in [4], but was mistakenly not mentioned in
         that paper.)

    This affects the seeding procedure by imposing the requirement
    s1 > 1, s2 > 7, s3 > 15.

 */
 struct nrnd_state {
 	u32 s1, s2, s3;
 };

 static DEFINE_PER_CPU(struct nrnd_state, net_rand_state);

 static u32 __net_random(struct nrnd_state *state)
 {
 #define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)

 	state->s1 = TAUSWORTHE(state->s1, 13, 19, 4294967294UL, 12);
 	state->s2 = TAUSWORTHE(state->s2, 2, 25, 4294967288UL, 4);
 	state->s3 = TAUSWORTHE(state->s3, 3, 11, 4294967280UL, 17);

 	return (state->s1 ^ state->s2 ^ state->s3);
 }

 static void __net_srandom(struct nrnd_state *state, unsigned long s)
 {
 	if (s == 0)
 		s = 1;      /* default seed is 1 */

 #define LCG(n) (69069 * n)
 	state->s1 = LCG(s);
 	state->s2 = LCG(state->s1);
 	state->s3 = LCG(state->s2);

 	/* "warm it up" */
 	__net_random(state);
 	__net_random(state);
 	__net_random(state);
 	__net_random(state);
 	__net_random(state);
 	__net_random(state);
 }


 unsigned long net_random(void)
 {
 	unsigned long r;
 	struct nrnd_state *state = &get_cpu_var(net_rand_state);
 	r = __net_random(state);
 	put_cpu_var(state);
 	return r;
 }


 void net_srandom(unsigned long entropy)
 {
 	struct nrnd_state *state = &get_cpu_var(net_rand_state);
 	__net_srandom(state, state->s1^entropy);
 	put_cpu_var(state);
 }

 void __init net_random_init(void)
 {
 	int i;

 	for_each_possible_cpu(i) {
 		struct nrnd_state *state = &per_cpu(net_rand_state,i);
 		__net_srandom(state, i+jiffies);
 	}
 }

 static int net_random_reseed(void)
 {
 	int i;
 	unsigned long seed;

 	for_each_possible_cpu(i) {
 		struct nrnd_state *state = &per_cpu(net_rand_state,i);

 		get_random_bytes(&seed, sizeof(seed));
 		__net_srandom(state, seed);
 	}
 	return 0;
 }
 late_initcall(net_random_reseed);

 int net_msg_cost = 5*HZ;
 int net_msg_burst = 10;

 /*
  * All net warning printk()s should be guarded by this function.
  */
 int net_ratelimit(void)
 {
 	return __printk_ratelimit(net_msg_cost, net_msg_burst);
 }

 EXPORT_SYMBOL(net_random);
 EXPORT_SYMBOL(net_ratelimit);
 EXPORT_SYMBOL(net_srandom);

 /*
  * 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 digit2bin(char c, char delim)
 {
 	if (c == delim || c == '\0')
 		return IN6PTON_DELIM;
 	if (c == '.')
 		return IN6PTON_DOT;
 	if (c >= '0' && c <= '9')
 		return (IN6PTON_DIGIT | (c - '0'));
 	return IN6PTON_UNKNOWN;
 }

 static inline int xdigit2bin(char c, char delim)
 {
 	if (c == delim || c == '\0')
 		return IN6PTON_DELIM;
 	if (c == ':')
 		return IN6PTON_COLON_MASK;
 	if (c == '.')
 		return IN6PTON_DOT;
 	if (c >= '0' && c <= '9')
 		return (IN6PTON_XDIGIT | IN6PTON_DIGIT| (c - '0'));
 	if (c >= 'a' && c <= 'f')
 		return (IN6PTON_XDIGIT | (c - 'a' + 10));
 	if (c >= 'A' && c <= 'F')
 		return (IN6PTON_XDIGIT | (c - 'A' + 10));
 	return IN6PTON_UNKNOWN;
 }

 int in4_pton(const char *src, int srclen,
 	     u8 *dst,
 	     char 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))) {
 			goto out;
 		}
 		if (c & (IN6PTON_DOT | IN6PTON_DELIM)) {
 			if (w == 0)
 				goto out;
 			*d++ = w & 0xff;
 			w = 0;
 			i++;
 			if (c & IN6PTON_DELIM) {
 				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);

 int in6_pton(const char *src, int srclen,
 	     u8 *dst,
 	     char 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);
	/*
	* 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/inet.h>
	#include <linux/mm.h>
	#include <linux/net.h>
	#include <linux/string.h>
	#include <linux/types.h>
	#include <linux/random.h>
	#include <linux/percpu.h>
	#include <linux/init.h>

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

	/*
	This is a maximally equidistributed combined Tausworthe generator
	based on code from GNU Scientific Library 1.5 (30 Jun 2004)

	x_n = (s1_n ^ s2_n ^ s3_n)

	s1_{n+1} = (((s1_n & 4294967294) <<12) ^ (((s1_n <<13) ^ s1_n) >>19))
	s2_{n+1} = (((s2_n & 4294967288) << 4) ^ (((s2_n << 2) ^ s2_n) >>25))
	s3_{n+1} = (((s3_n & 4294967280) <<17) ^ (((s3_n << 3) ^ s3_n) >>11))

	The period of this generator is about 2^88.

	From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
	Generators", Mathematics of Computation, 65, 213 (1996), 203--213.

	This is available on the net from L'Ecuyer's home page,

	http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
	ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps

	There is an erratum in the paper "Tables of Maximally
	Equidistributed Combined LFSR Generators", Mathematics of
	Computation, 68, 225 (1999), 261--269:
	http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps

	... the k_j most significant bits of z_j must be non-
	zero, for each j. (Note: this restriction also applies to the
	computer code given in [4], but was mistakenly not mentioned in
	that paper.)

	This affects the seeding procedure by imposing the requirement
	s1 > 1, s2 > 7, s3 > 15.

	*/
	struct nrnd_state {
	u32 s1, s2, s3;
	};

	static DEFINE_PER_CPU(struct nrnd_state, net_rand_state);

	static u32 __net_random(struct nrnd_state *state)
	{
	#define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)

	state->s1 = TAUSWORTHE(state->s1, 13, 19, 4294967294UL, 12);
	state->s2 = TAUSWORTHE(state->s2, 2, 25, 4294967288UL, 4);
	state->s3 = TAUSWORTHE(state->s3, 3, 11, 4294967280UL, 17);

	return (state->s1 ^ state->s2 ^ state->s3);
	}

	static void __net_srandom(struct nrnd_state *state, unsigned long s)
	{
	if (s == 0)
	s = 1; /* default seed is 1 */

	#define LCG(n) (69069 * n)
	state->s1 = LCG(s);
	state->s2 = LCG(state->s1);
	state->s3 = LCG(state->s2);

	/* "warm it up" */
	__net_random(state);
	__net_random(state);
	__net_random(state);
	__net_random(state);
	__net_random(state);
	__net_random(state);
	}


	unsigned long net_random(void)
	{
	unsigned long r;
	struct nrnd_state *state = &get_cpu_var(net_rand_state);
	r = __net_random(state);
	put_cpu_var(state);
	return r;
	}


	void net_srandom(unsigned long entropy)
	{
	struct nrnd_state *state = &get_cpu_var(net_rand_state);
	__net_srandom(state, state->s1^entropy);
	put_cpu_var(state);
	}

	void __init net_random_init(void)
	{
	int i;

	for_each_possible_cpu(i) {
	struct nrnd_state *state = &per_cpu(net_rand_state,i);
	__net_srandom(state, i+jiffies);
	}
	}

	static int net_random_reseed(void)
	{
	int i;
	unsigned long seed;

	for_each_possible_cpu(i) {
	struct nrnd_state *state = &per_cpu(net_rand_state,i);

	get_random_bytes(&seed, sizeof(seed));
	__net_srandom(state, seed);
	}
	return 0;
	}
	late_initcall(net_random_reseed);

	int net_msg_cost = 5*HZ;
	int net_msg_burst = 10;

	/*
	* All net warning printk()s should be guarded by this function.
	*/
	int net_ratelimit(void)
	{
	return __printk_ratelimit(net_msg_cost, net_msg_burst);
	}

	EXPORT_SYMBOL(net_random);
	EXPORT_SYMBOL(net_ratelimit);
	EXPORT_SYMBOL(net_srandom);

	/*
	* 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 digit2bin(char c, char delim)
	{
	if (c == delim \|\| c == '\0')
	return IN6PTON_DELIM;
	if (c == '.')
	return IN6PTON_DOT;
	if (c >= '0' && c <= '9')
	return (IN6PTON_DIGIT \| (c - '0'));
	return IN6PTON_UNKNOWN;
	}

	static inline int xdigit2bin(char c, char delim)
	{
	if (c == delim \|\| c == '\0')
	return IN6PTON_DELIM;
	if (c == ':')
	return IN6PTON_COLON_MASK;
	if (c == '.')
	return IN6PTON_DOT;
	if (c >= '0' && c <= '9')
	return (IN6PTON_XDIGIT \| IN6PTON_DIGIT\| (c - '0'));
	if (c >= 'a' && c <= 'f')
	return (IN6PTON_XDIGIT \| (c - 'a' + 10));
	if (c >= 'A' && c <= 'F')
	return (IN6PTON_XDIGIT \| (c - 'A' + 10));
	return IN6PTON_UNKNOWN;
	}

	int in4_pton(const char *src, int srclen,
	u8 *dst,
	char 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))) {
	goto out;
	}
	if (c & (IN6PTON_DOT \| IN6PTON_DELIM)) {
	if (w == 0)
	goto out;
	*d++ = w & 0xff;
	w = 0;
	i++;
	if (c & IN6PTON_DELIM) {
	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);

	int in6_pton(const char *src, int srclen,
	u8 *dst,
	char 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);