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![YOSHIFUJI Hideaki](/assets/img/avatar_default.png)
These helpers can be used in netfilter, cifs etc. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
408 lines
8.7 KiB
C
408 lines
8.7 KiB
C
/*
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* Generic address resultion entity
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*
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* Authors:
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* net_random Alan Cox
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* net_ratelimit Andy Kleen
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* in{4,6}_pton YOSHIFUJI Hideaki, Copyright (C)2006 USAGI/WIDE Project
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*
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* Created by Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/jiffies.h>
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#include <linux/kernel.h>
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#include <linux/inet.h>
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#include <linux/mm.h>
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#include <linux/net.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/random.h>
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#include <linux/percpu.h>
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#include <linux/init.h>
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#include <asm/byteorder.h>
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#include <asm/system.h>
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#include <asm/uaccess.h>
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/*
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This is a maximally equidistributed combined Tausworthe generator
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based on code from GNU Scientific Library 1.5 (30 Jun 2004)
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x_n = (s1_n ^ s2_n ^ s3_n)
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s1_{n+1} = (((s1_n & 4294967294) <<12) ^ (((s1_n <<13) ^ s1_n) >>19))
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s2_{n+1} = (((s2_n & 4294967288) << 4) ^ (((s2_n << 2) ^ s2_n) >>25))
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s3_{n+1} = (((s3_n & 4294967280) <<17) ^ (((s3_n << 3) ^ s3_n) >>11))
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The period of this generator is about 2^88.
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From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
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Generators", Mathematics of Computation, 65, 213 (1996), 203--213.
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This is available on the net from L'Ecuyer's home page,
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http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
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ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps
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There is an erratum in the paper "Tables of Maximally
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Equidistributed Combined LFSR Generators", Mathematics of
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Computation, 68, 225 (1999), 261--269:
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http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
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... the k_j most significant bits of z_j must be non-
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zero, for each j. (Note: this restriction also applies to the
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computer code given in [4], but was mistakenly not mentioned in
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that paper.)
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This affects the seeding procedure by imposing the requirement
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s1 > 1, s2 > 7, s3 > 15.
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*/
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struct nrnd_state {
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u32 s1, s2, s3;
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};
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static DEFINE_PER_CPU(struct nrnd_state, net_rand_state);
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static u32 __net_random(struct nrnd_state *state)
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{
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#define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)
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state->s1 = TAUSWORTHE(state->s1, 13, 19, 4294967294UL, 12);
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state->s2 = TAUSWORTHE(state->s2, 2, 25, 4294967288UL, 4);
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state->s3 = TAUSWORTHE(state->s3, 3, 11, 4294967280UL, 17);
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return (state->s1 ^ state->s2 ^ state->s3);
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}
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static void __net_srandom(struct nrnd_state *state, unsigned long s)
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{
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if (s == 0)
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s = 1; /* default seed is 1 */
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#define LCG(n) (69069 * n)
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state->s1 = LCG(s);
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state->s2 = LCG(state->s1);
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state->s3 = LCG(state->s2);
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/* "warm it up" */
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__net_random(state);
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__net_random(state);
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__net_random(state);
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__net_random(state);
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__net_random(state);
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__net_random(state);
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}
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unsigned long net_random(void)
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{
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unsigned long r;
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struct nrnd_state *state = &get_cpu_var(net_rand_state);
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r = __net_random(state);
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put_cpu_var(state);
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return r;
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}
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void net_srandom(unsigned long entropy)
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{
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struct nrnd_state *state = &get_cpu_var(net_rand_state);
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__net_srandom(state, state->s1^entropy);
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put_cpu_var(state);
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}
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void __init net_random_init(void)
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{
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int i;
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for_each_possible_cpu(i) {
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struct nrnd_state *state = &per_cpu(net_rand_state,i);
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__net_srandom(state, i+jiffies);
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}
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}
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static int net_random_reseed(void)
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{
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int i;
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unsigned long seed;
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for_each_possible_cpu(i) {
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struct nrnd_state *state = &per_cpu(net_rand_state,i);
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get_random_bytes(&seed, sizeof(seed));
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__net_srandom(state, seed);
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}
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return 0;
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}
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late_initcall(net_random_reseed);
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int net_msg_cost = 5*HZ;
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int net_msg_burst = 10;
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/*
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* All net warning printk()s should be guarded by this function.
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*/
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int net_ratelimit(void)
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{
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return __printk_ratelimit(net_msg_cost, net_msg_burst);
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}
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EXPORT_SYMBOL(net_random);
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EXPORT_SYMBOL(net_ratelimit);
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EXPORT_SYMBOL(net_srandom);
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/*
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* Convert an ASCII string to binary IP.
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* This is outside of net/ipv4/ because various code that uses IP addresses
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* is otherwise not dependent on the TCP/IP stack.
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*/
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__be32 in_aton(const char *str)
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{
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unsigned long l;
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unsigned int val;
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int i;
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l = 0;
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for (i = 0; i < 4; i++)
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{
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l <<= 8;
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if (*str != '\0')
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{
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val = 0;
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while (*str != '\0' && *str != '.' && *str != '\n')
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{
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val *= 10;
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val += *str - '0';
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str++;
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}
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l |= val;
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if (*str != '\0')
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str++;
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}
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}
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return(htonl(l));
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}
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EXPORT_SYMBOL(in_aton);
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#define IN6PTON_XDIGIT 0x00010000
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#define IN6PTON_DIGIT 0x00020000
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#define IN6PTON_COLON_MASK 0x00700000
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#define IN6PTON_COLON_1 0x00100000 /* single : requested */
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#define IN6PTON_COLON_2 0x00200000 /* second : requested */
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#define IN6PTON_COLON_1_2 0x00400000 /* :: requested */
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#define IN6PTON_DOT 0x00800000 /* . */
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#define IN6PTON_DELIM 0x10000000
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#define IN6PTON_NULL 0x20000000 /* first/tail */
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#define IN6PTON_UNKNOWN 0x40000000
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static inline int digit2bin(char c, char delim)
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{
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if (c == delim || c == '\0')
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return IN6PTON_DELIM;
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if (c == '.')
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return IN6PTON_DOT;
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if (c >= '0' && c <= '9')
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return (IN6PTON_DIGIT | (c - '0'));
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return IN6PTON_UNKNOWN;
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}
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static inline int xdigit2bin(char c, char delim)
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{
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if (c == delim || c == '\0')
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return IN6PTON_DELIM;
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if (c == ':')
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return IN6PTON_COLON_MASK;
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if (c == '.')
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return IN6PTON_DOT;
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if (c >= '0' && c <= '9')
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return (IN6PTON_XDIGIT | IN6PTON_DIGIT| (c - '0'));
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if (c >= 'a' && c <= 'f')
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return (IN6PTON_XDIGIT | (c - 'a' + 10));
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if (c >= 'A' && c <= 'F')
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return (IN6PTON_XDIGIT | (c - 'A' + 10));
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return IN6PTON_UNKNOWN;
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}
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int in4_pton(const char *src, int srclen,
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u8 *dst,
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char delim, const char **end)
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{
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const char *s;
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u8 *d;
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u8 dbuf[4];
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int ret = 0;
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int i;
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int w = 0;
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if (srclen < 0)
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srclen = strlen(src);
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s = src;
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d = dbuf;
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i = 0;
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while(1) {
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int c;
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c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
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if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM))) {
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goto out;
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}
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if (c & (IN6PTON_DOT | IN6PTON_DELIM)) {
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if (w == 0)
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goto out;
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*d++ = w & 0xff;
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w = 0;
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i++;
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if (c & IN6PTON_DELIM) {
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if (i != 4)
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goto out;
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break;
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}
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goto cont;
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}
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w = (w * 10) + c;
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if ((w & 0xffff) > 255) {
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goto out;
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}
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cont:
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if (i >= 4)
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goto out;
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s++;
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srclen--;
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}
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ret = 1;
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memcpy(dst, dbuf, sizeof(dbuf));
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out:
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if (end)
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*end = s;
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return ret;
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}
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EXPORT_SYMBOL(in4_pton);
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int in6_pton(const char *src, int srclen,
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u8 *dst,
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char delim, const char **end)
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{
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const char *s, *tok = NULL;
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u8 *d, *dc = NULL;
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u8 dbuf[16];
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int ret = 0;
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int i;
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int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
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int w = 0;
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memset(dbuf, 0, sizeof(dbuf));
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s = src;
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d = dbuf;
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if (srclen < 0)
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srclen = strlen(src);
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printf("srclen=%d\n", srclen);
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while (1) {
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int c;
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c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
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if (!(c & state))
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goto out;
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if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
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/* process one 16-bit word */
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if (!(state & IN6PTON_NULL)) {
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*d++ = (w >> 8) & 0xff;
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*d++ = w & 0xff;
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}
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w = 0;
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if (c & IN6PTON_DELIM) {
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/* We've processed last word */
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break;
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}
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/*
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* COLON_1 => XDIGIT
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* COLON_2 => XDIGIT|DELIM
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* COLON_1_2 => COLON_2
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*/
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switch (state & IN6PTON_COLON_MASK) {
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case IN6PTON_COLON_2:
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dc = d;
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state = IN6PTON_XDIGIT | IN6PTON_DELIM;
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if (dc - dbuf >= sizeof(dbuf))
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state |= IN6PTON_NULL;
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break;
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case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
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state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
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break;
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case IN6PTON_COLON_1:
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state = IN6PTON_XDIGIT;
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break;
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case IN6PTON_COLON_1_2:
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state = IN6PTON_COLON_2;
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break;
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default:
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state = 0;
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}
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tok = s + 1;
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goto cont;
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}
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if (c & IN6PTON_DOT) {
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ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
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if (ret > 0) {
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d += 4;
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break;
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}
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goto out;
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}
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w = (w << 4) | (0xff & c);
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state = IN6PTON_COLON_1 | IN6PTON_DELIM;
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if (!(w & 0xf000)) {
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state |= IN6PTON_XDIGIT;
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}
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if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
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state |= IN6PTON_COLON_1_2;
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state &= ~IN6PTON_DELIM;
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}
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if (d + 2 >= dbuf + sizeof(dbuf)) {
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state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
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}
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cont:
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if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
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d + 4 == dbuf + sizeof(dbuf)) {
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state |= IN6PTON_DOT;
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}
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if (d >= dbuf + sizeof(dbuf)) {
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state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
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}
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s++;
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srclen--;
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}
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i = 15; d--;
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if (dc) {
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while(d >= dc)
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dst[i--] = *d--;
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while(i >= dc - dbuf)
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dst[i--] = 0;
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while(i >= 0)
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dst[i--] = *d--;
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} else
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memcpy(dst, dbuf, sizeof(dbuf));
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ret = 1;
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out:
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if (end)
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*end = s;
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return ret;
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}
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EXPORT_SYMBOL(in6_pton);
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