mirror of
https://gitlab.nic.cz/labs/bird.git
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385 lines
7.1 KiB
C
385 lines
7.1 KiB
C
/*
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* BIRD Library -- IPv6 Address Manipulation Functions
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*
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* (c) 1999 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#include <stdlib.h>
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#include "nest/bird.h"
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#include "lib/ip.h"
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#include "lib/bitops.h"
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#include "lib/endian.h"
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#include "lib/string.h"
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/*
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* See RFC 2373 for explanation of IPv6 addressing issues.
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*/
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ip_addr
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ipv6_mkmask(unsigned n)
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{
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ip_addr a;
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int i;
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for(i=0; i<4; i++)
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{
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if (!n)
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a.addr[i] = 0;
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else if (n >= 32)
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{
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a.addr[i] = ~0;
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n -= 32;
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}
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else
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{
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a.addr[i] = u32_mkmask(n);
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n = 0;
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}
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}
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return a;
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}
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unsigned
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ipv6_mklen(ip_addr *a)
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{
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int i, j, n;
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for(i=0, n=0; i<4; i++, n+=32)
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if (a->addr[i] != ~0U)
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{
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j = u32_masklen(a->addr[i]);
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if (j < 0)
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return j;
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n += j;
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while (++i < 4)
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if (a->addr[i])
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return -1;
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break;
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}
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return n;
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}
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int
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ipv6_classify(ip_addr *a)
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{
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u32 x = a->addr[0];
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if ((x & 0xe0000000) == 0x20000000) /* 2000::/3 Aggregatable Global Unicast Address */
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return IADDR_HOST | SCOPE_UNIVERSE;
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if ((x & 0xffc00000) == 0xfe800000) /* fe80::/10 Link-Local Address */
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return IADDR_HOST | SCOPE_LINK;
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if ((x & 0xffc00000) == 0xfec00000) /* fec0::/10 Site-Local Address */
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return IADDR_HOST | SCOPE_SITE;
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if ((x & 0xfe000000) == 0xfc000000) /* fc00::/7 Unique Local Unicast Address (RFC 4193) */
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return IADDR_HOST | SCOPE_SITE;
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if ((x & 0xff000000) == 0xff000000) /* ff00::/8 Multicast Address */
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{
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unsigned int scope = (x >> 16) & 0x0f;
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switch (scope)
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{
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case 1: return IADDR_MULTICAST | SCOPE_HOST;
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case 2: return IADDR_MULTICAST | SCOPE_LINK;
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case 5: return IADDR_MULTICAST | SCOPE_SITE;
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case 8: return IADDR_MULTICAST | SCOPE_ORGANIZATION;
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case 14: return IADDR_MULTICAST | SCOPE_UNIVERSE;
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default: return IADDR_MULTICAST | SCOPE_UNDEFINED;
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}
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}
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if (!x && !a->addr[1] && !a->addr[2])
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{
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u32 y = a->addr[3];
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if (y == 1)
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return IADDR_HOST | SCOPE_HOST; /* Loopback address */
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/* IPv4 compatible addresses */
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if (y >= 0x7f000000 && y < 0x80000000)
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return IADDR_HOST | SCOPE_HOST;
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if ((y & 0xff000000) == 0x0a000000 ||
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(y & 0xffff0000) == 0xc0a80000 ||
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(y & 0xfff00000) == 0xac100000)
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return IADDR_HOST | SCOPE_SITE;
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if (y >= 0x01000000 && y < 0xe0000000)
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return IADDR_HOST | SCOPE_UNIVERSE;
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}
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return IADDR_HOST | SCOPE_UNDEFINED;
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}
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void
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ipv6_hton(ip_addr *a)
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{
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int i;
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for(i=0; i<4; i++)
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a->addr[i] = htonl(a->addr[i]);
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}
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void
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ipv6_ntoh(ip_addr *a)
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{
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int i;
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for(i=0; i<4; i++)
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a->addr[i] = ntohl(a->addr[i]);
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}
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int
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ipv6_compare(ip_addr X, ip_addr Y)
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{
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int i;
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ip_addr *x = &X;
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ip_addr *y = &Y;
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for(i=0; i<4; i++)
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if (x->addr[i] > y->addr[i])
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return 1;
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else if (x->addr[i] < y->addr[i])
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return -1;
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return 0;
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}
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/*
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* Conversion of IPv6 address to presentation format and vice versa.
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* Heavily inspired by routines written by Paul Vixie for the BIND project
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* and of course by RFC 2373.
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*/
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char *
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ip_ntop(ip_addr a, char *b)
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{
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u16 words[8];
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int bestpos, bestlen, curpos, curlen, i;
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/* First of all, preprocess the address and find the longest run of zeros */
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bestlen = bestpos = curpos = curlen = 0;
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for(i=0; i<8; i++)
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{
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u32 x = a.addr[i/2];
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words[i] = ((i%2) ? x : (x >> 16)) & 0xffff;
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if (words[i])
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curlen = 0;
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else
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{
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if (!curlen)
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curpos = i;
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curlen++;
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if (curlen > bestlen)
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{
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bestpos = curpos;
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bestlen = curlen;
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}
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}
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}
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if (bestlen < 2)
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bestpos = -1;
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/* Is it an encapsulated IPv4 address? */
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if (!bestpos &&
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(bestlen == 5 && a.addr[2] == 0xffff ||
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bestlen == 6))
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{
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u32 x = a.addr[3];
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b += bsprintf(b, "::%s%d.%d.%d.%d",
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a.addr[2] ? "ffff:" : "",
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((x >> 24) & 0xff),
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((x >> 16) & 0xff),
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((x >> 8) & 0xff),
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(x & 0xff));
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return b;
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}
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/* Normal IPv6 formatting, compress the largest sequence of zeros */
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for(i=0; i<8; i++)
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{
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if (i == bestpos)
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{
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i += bestlen - 1;
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*b++ = ':';
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if (i == 7)
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*b++ = ':';
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}
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else
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{
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if (i)
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*b++ = ':';
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b += bsprintf(b, "%x", words[i]);
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}
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}
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*b = 0;
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return b;
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}
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char *
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ip_ntox(ip_addr a, char *b)
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{
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int i;
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for(i=0; i<4; i++)
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{
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if (i)
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*b++ = '.';
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b += bsprintf(b, "%08x", a.addr[i]);
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}
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return b;
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}
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int
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ipv4_pton_u32(char *a, u32 *o)
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{
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int i;
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unsigned long int l;
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u32 ia = 0;
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i=4;
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while (i--)
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{
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char *d, *c = strchr(a, '.');
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if (!c != !i)
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return 0;
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l = strtoul(a, &d, 10);
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if (d != c && *d || l > 255)
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return 0;
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ia = (ia << 8) | l;
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if (c)
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c++;
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a = c;
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}
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*o = ia;
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return 1;
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}
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int
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ip_pton(char *a, ip_addr *o)
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{
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u16 words[8];
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int i, j, k, l, hfil;
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char *start;
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if (a[0] == ':') /* Leading :: */
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{
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if (a[1] != ':')
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return 0;
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a++;
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}
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hfil = -1;
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i = 0;
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while (*a)
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{
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if (*a == ':') /* :: */
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{
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if (hfil >= 0)
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return 0;
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hfil = i;
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a++;
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continue;
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}
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j = 0;
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l = 0;
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start = a;
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for(;;)
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{
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if (*a >= '0' && *a <= '9')
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k = *a++ - '0';
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else if (*a >= 'A' && *a <= 'F')
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k = *a++ - 'A' + 10;
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else if (*a >= 'a' && *a <= 'f')
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k = *a++ - 'a' + 10;
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else
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break;
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j = (j << 4) + k;
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if (j >= 0x10000 || ++l > 4)
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return 0;
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}
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if (*a == ':' && a[1])
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a++;
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else if (*a == '.' && (i == 6 || i < 6 && hfil >= 0))
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{ /* Embedded IPv4 address */
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u32 x;
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if (!ipv4_pton_u32(start, &x))
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return 0;
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words[i++] = x >> 16;
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words[i++] = x;
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break;
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}
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else if (*a)
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return 0;
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if (i >= 8)
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return 0;
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words[i++] = j;
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}
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/* Replace :: with an appropriate number of zeros */
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if (hfil >= 0)
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{
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j = 8 - i;
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for(i=7; i-j >= hfil; i--)
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words[i] = words[i-j];
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for(; i>=hfil; i--)
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words[i] = 0;
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}
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/* Convert the address to ip_addr format */
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for(i=0; i<4; i++)
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o->addr[i] = (words[2*i] << 16) | words[2*i+1];
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return 1;
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}
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void ipv6_absolutize(ip_addr *a, ip_addr *ifa)
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{
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if ((a->addr[0] & 0xffc00000) == 0xfe800000 && /* a is link-scope */
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((ifa->addr[0] & 0xe0000000) == 0x20000000 | /* ifa is AGU ... */
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(ifa->addr[0] & 0xffc00000) == 0xfec00000)) /* ... or site-scope */
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{
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a->addr[0] = ifa->addr[0]; /* Copy the prefix, leave interface ID */
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a->addr[1] = ifa->addr[1];
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}
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}
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#ifdef TEST
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#include "bitops.c"
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static void test(char *x)
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{
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ip_addr a;
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char c[STD_ADDRESS_P_LENGTH+1];
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printf("%-40s ", x);
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if (!ip_pton(x, &a))
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{
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puts("BAD");
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return;
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}
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ip_ntop(a, c);
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printf("%-40s %04x\n", c, ipv6_classify(&a));
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}
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int main(void)
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{
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puts("Positive tests:");
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test("1:2:3:4:5:6:7:8");
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test("dead:beef:DEAD:BEEF::f00d");
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test("::");
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test("::1");
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test("1::");
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test("::1.234.5.6");
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test("::ffff:1.234.5.6");
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test("::fffe:1.234.5.6");
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test("1:2:3:4:5:6:7::8");
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test("2080::8:800:200c:417a");
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test("ff01::101");
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puts("Negative tests:");
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test(":::");
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test("1:2:3:4:5:6:7:8:");
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test("1::2::3");
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test("::12345");
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test("::1.2.3.4:5");
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test(":1:2:3:4:5:6:7:8");
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test("g:1:2:3:4:5:6:7");
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return 0;
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}
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#endif
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