417 lines
12 KiB
C
417 lines
12 KiB
C
/*
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* IP address pool functions.
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* Copyright (C) 2003 Mondru AB.
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*
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* The contents of this file may be used under the terms of the GNU
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* General Public License Version 2, provided that the above copyright
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* notice and this permission notice is included in all copies or
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* substantial portions of the software.
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*
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* The initial developer of the original code is
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* Jens Jakobsen <jj@openggsn.org>
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*
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* Contributor(s):
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*
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*/
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#include <netinet/in.h> /* in_addr */
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#include <stdlib.h> /* calloc */
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#include <stdio.h> /* sscanf */
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#include "ippool.h"
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/*
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--------------------------------------------------------------------
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Public domain by From Bob Jenkins, December 1996.
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mix -- mix 3 32-bit values reversibly.
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For every delta with one or two bit set, and the deltas of all three
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high bits or all three low bits, whether the original value of a,b,c
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is almost all zero or is uniformly distributed,
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* If mix() is run forward or backward, at least 32 bits in a,b,c
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have at least 1/4 probability of changing.
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* If mix() is run forward, every bit of c will change between 1/3 and
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2/3 of the time. (Well, 22/100 and 78/100 for some 2-bit deltas.)
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mix() was built out of 36 single-cycle latency instructions in a
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structure that could supported 2x parallelism, like so:
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a -= b;
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a -= c; x = (c>>13);
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b -= c; a ^= x;
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b -= a; x = (a<<8);
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c -= a; b ^= x;
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c -= b; x = (b>>13);
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...
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Unfortunately, superscalar Pentiums and Sparcs can't take advantage
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of that parallelism. They've also turned some of those single-cycle
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latency instructions into multi-cycle latency instructions. Still,
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this is the fastest good hash I could find. There were about 2^^68
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to choose from. I only looked at a billion or so.
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--------------------------------------------------------------------
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*/
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#define mix(a,b,c) \
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{ \
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a -= b; a -= c; a ^= (c>>13); \
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b -= c; b -= a; b ^= (a<<8); \
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c -= a; c -= b; c ^= (b>>13); \
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a -= b; a -= c; a ^= (c>>12); \
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b -= c; b -= a; b ^= (a<<16); \
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c -= a; c -= b; c ^= (b>>5); \
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a -= b; a -= c; a ^= (c>>3); \
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b -= c; b -= a; b ^= (a<<10); \
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c -= a; c -= b; c ^= (b>>15); \
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}
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/*
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--------------------------------------------------------------------
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lookup() -- hash a variable-length key into a 32-bit value
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k : the key (the unaligned variable-length array of bytes)
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len : the length of the key, counting by bytes
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level : can be any 4-byte value
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Returns a 32-bit value. Every bit of the key affects every bit of
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the return value. Every 1-bit and 2-bit delta achieves avalanche.
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About 6len+35 instructions.
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The best hash table sizes are powers of 2. There is no need to do
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mod a prime (mod is sooo slow!). If you need less than 32 bits,
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use a bitmask. For example, if you need only 10 bits, do
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h = (h & hashmask(10));
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In which case, the hash table should have hashsize(10) elements.
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If you are hashing n strings (ub1 **)k, do it like this:
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for (i=0, h=0; i<n; ++i) h = lookup( k[i], len[i], h);
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By Bob Jenkins, 1996. bob_jenkins@burtleburtle.net. You may use this
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code any way you wish, private, educational, or commercial.
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See http://burtleburtle.net/bob/hash/evahash.html
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Use for hash table lookup, or anything where one collision in 2^32 is
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acceptable. Do NOT use for cryptographic purposes.
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--------------------------------------------------------------------
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*/
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unsigned long int lookup( k, length, level)
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register unsigned char *k; /* the key */
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register unsigned long int length; /* the length of the key */
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register unsigned long int level; /* the previous hash, or an arbitrary value */
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{
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register unsigned long int a,b,c,len;
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/* Set up the internal state */
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len = length;
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a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */
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c = level; /* the previous hash value */
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/*---------------------------------------- handle most of the key */
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while (len >= 12)
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{
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a += (k[0] +((ub4)k[1]<<8) +((ub4)k[2]<<16) +((ub4)k[3]<<24));
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b += (k[4] +((ub4)k[5]<<8) +((ub4)k[6]<<16) +((ub4)k[7]<<24));
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c += (k[8] +((ub4)k[9]<<8) +((ub4)k[10]<<16)+((ub4)k[11]<<24));
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mix(a,b,c);
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k += 12; len -= 12;
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}
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/*------------------------------------- handle the last 11 bytes */
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c += length;
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switch(len) /* all the case statements fall through */
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{
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case 11: c+=((ub4)k[10]<<24);
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case 10: c+=((ub4)k[9]<<16);
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case 9 : c+=((ub4)k[8]<<8);
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/* the first byte of c is reserved for the length */
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case 8 : b+=((ub4)k[7]<<24);
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case 7 : b+=((ub4)k[6]<<16);
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case 6 : b+=((ub4)k[5]<<8);
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case 5 : b+=k[4];
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case 4 : a+=((ub4)k[3]<<24);
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case 3 : a+=((ub4)k[2]<<16);
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case 2 : a+=((ub4)k[1]<<8);
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case 1 : a+=k[0];
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/* case 0: nothing left to add */
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}
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mix(a,b,c);
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/*-------------------------------------------- report the result */
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return c;
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}
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/*
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End of public domain code by From Bob Jenkins, December 1996.
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--------------------------------------------------------------------
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*/
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int ippool_printaddr(struct ippool_t *this) {
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int n;
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printf("ippool_printaddr\n");
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printf("First %d\n", this->first - this->member);
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printf("Last %d\n", this->last - this->member);
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printf("Listsize %d\n", this->listsize);
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for (n=0; n<this->listsize; n++) {
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printf("Unit %d inuse %d prev %d next %d addr %x\n",
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n,
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this->member[n].inuse,
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this->member[n].prev - this->member,
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this->member[n].next - this->member,
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this->member[n].addr.s_addr
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);
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}
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return 0;
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}
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unsigned long int ippool_hash4(struct in_addr *addr) {
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return lookup(&addr->s_addr, sizeof(addr->s_addr), 0);
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}
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#ifndef IPPOOL_NOIP6
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unsigned long int ippool_hash6(struct in6_addr *addr) {
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return lookup(addr->u6_addr8, sizeof(addr->u6_addr8), 0);
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}
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#endif
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/* Get IP address and mask */
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int ippool_aton(struct in_addr *addr, struct in_addr *mask,
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char *pool, int number) {
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/* Parse only first instance of network for now */
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/* Eventually "number" will indicate the token which we want to parse */
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unsigned int a1, a2, a3, a4;
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unsigned int m1, m2, m3, m4;
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int c;
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unsigned int m;
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int masklog;
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c = sscanf(pool, "%u.%u.%u.%u/%u.%u.%u.%u",
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&a1, &a2, &a3, &a4,
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&m1, &m2, &m3, &m4);
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switch (c) {
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case 4:
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if (a1 == 0 && a2 == 0 && a3 == 0 && a4 == 0) /* Full Internet */
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mask->s_addr = 0x00000000;
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else if (a2 == 0 && a3 == 0 && a4 == 0) /* class A */
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mask->s_addr = htonl(0xff000000);
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else if (a3 == 0 && a4 == 0) /* class B */
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mask->s_addr = htonl(0xffff0000);
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else if (a4 == 0) /* class C */
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mask->s_addr = htonl(0xffffff00);
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else
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mask->s_addr = 0xffffffff;
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break;
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case 5:
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if (m1 < 0 || m1 > 32) {
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return -1; /* Invalid mask */
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}
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mask->s_addr = htonl(0xffffffff << (32 - m1));
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break;
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case 8:
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if (m1 >= 256 || m2 >= 256 || m3 >= 256 || m4 >= 256)
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return -1; /* Wrong mask format */
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m = m1 * 0x1000000 + m2 * 0x10000 + m3 * 0x100 + m4;
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for (masklog = 0; ((1 << masklog) < ((~m)+1)); masklog++);
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if (((~m)+1) != (1 << masklog))
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return -1; /* Wrong mask format (not all ones followed by all zeros)*/
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mask->s_addr = htonl(m);
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break;
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default:
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return -1; /* Invalid mask */
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}
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if (a1 >= 256 || a2 >= 256 || a3 >= 256 || a4 >= 256)
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return -1; /* Wrong IP address format */
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else
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addr->s_addr = htonl(a1 * 0x1000000 + a2 * 0x10000 + a3 * 0x100 + a4);
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return 0;
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}
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/* Create new address pool */
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int ippool_new(struct ippool_t **this, char *pool, int flags) {
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/* Parse only first instance of network for now */
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int i;
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struct ippoolm_t *p;
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struct ippoolm_t *p_prev = NULL;
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uint32_t hash;
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struct in_addr addr;
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struct in_addr mask;
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unsigned int m;
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unsigned int listsize;
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if (ippool_aton(&addr, &mask, pool, 0))
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return 0; /* Failed to parse pool */
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m = ntohl(mask.s_addr);
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listsize = ((~m)+1);
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if (flags & IPPOOL_NONETWORK) /* Exclude network address from pool */
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listsize--;
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if (flags & IPPOOL_NOBROADCAST) /* Exclude broadcast address from pool */
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listsize--;
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if (!(*this = calloc(sizeof(struct ippool_t), 1))) {
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/* Failed to allocate memory for ippool */
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return -1;
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}
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(*this)->listsize += listsize;
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if (!((*this)->member = calloc(sizeof(struct ippoolm_t), (*this)->listsize))){
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/* Failed to allocate memory for members in ippool */
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return -1;
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}
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for ((*this)->hashlog = 0;
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((1 << (*this)->hashlog) < listsize);
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(*this)->hashlog++);
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/* printf ("Hashlog %d %d %d\n", (*this)->hashlog, listsize, (1 << (*this)->hashlog)); */
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/* Determine hashsize */
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(*this)->hashsize = 1 << (*this)->hashlog; /* Fails if mask=0: All Internet*/
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(*this)->hashmask = (*this)->hashsize -1;
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/* Allocate hash table */
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if (!((*this)->hash = calloc(sizeof(struct ippoolm_t), (*this)->hashsize))){
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/* Failed to allocate memory for hash members in ippool */
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return -1;
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}
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(*this)->first = NULL;
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(*this)->last = NULL;
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for (i = 0; i<(*this)->listsize; i++) {
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if (flags & IPPOOL_NONETWORK)
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(*this)->member[i].addr.s_addr = htonl(ntohl(addr.s_addr) + i + 1);
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else
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(*this)->member[i].addr.s_addr = htonl(ntohl(addr.s_addr) + i);
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(*this)->member[i].inuse = 0;
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(*this)->member[i].parent = *this;
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/* Insert into list of unused */
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(*this)->member[i].prev = (*this)->last;
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if ((*this)->last) {
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(*this)->last->next = &((*this)->member[i]);
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}
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else {
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(*this)->first = &((*this)->member[i]);
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}
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(*this)->last = &((*this)->member[i]);
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(*this)->member[i].next = NULL; /* Redundant */
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/* Insert into hash table */
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hash = ippool_hash4(&(*this)->member[i].addr) & (*this)->hashmask;
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for (p = (*this)->hash[hash]; p; p = p->nexthash)
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p_prev = p;
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if (!p_prev)
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(*this)->hash[hash] = &((*this)->member[i]);
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else
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p_prev->nexthash = &((*this)->member[i]);
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}
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/*ippool_printaddr(*this);*/
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return 0;
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}
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/* Delete existing address pool */
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int ippool_free(struct ippool_t *this) {
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free(this->hash);
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free(this->member);
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free(this);
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return 0; /* Always OK */
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}
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/* Find an IP address in the pool */
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int ippool_getip(struct ippool_t *this, struct ippoolm_t **member,
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struct in_addr *addr) {
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struct ippoolm_t *p;
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uint32_t hash;
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/* Find in hash table */
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hash = ippool_hash4(addr) & this->hashmask;
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for (p = this->hash[hash]; p; p = p->nexthash) {
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if ((p->addr.s_addr == addr->s_addr) && (p->inuse)) {
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*member = p;
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return 0;
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}
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}
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*member = NULL;
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return -1; /* Address could not be found */
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}
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/* Get an IP address. If addr = 0.0.0.0 get a dynamic IP address. Otherwise
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check to see if the given address is available */
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int ippool_newip(struct ippool_t *this, struct ippoolm_t **member,
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struct in_addr *addr) {
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struct ippoolm_t *p;
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struct ippoolm_t *p2 = NULL;
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uint32_t hash;
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/*ippool_printaddr(this);*/
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if ((addr) && (addr->s_addr)) { /* IP address given */
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/* Find in hash table */
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hash = ippool_hash4(addr) & this->hashmask;
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for (p = this->hash[hash]; p; p = p->nexthash) {
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if ((p->addr.s_addr == addr->s_addr)) {
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p2 = p;
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break;
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}
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}
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}
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else { /* No ip address given */
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p2 = this -> first;
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}
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if (!p2) return -1; /* Not found */
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if (p2->inuse) return -1; /* Allready in use / Should not happen */
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/* Found new address. Remove from queue */
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if (p2->prev)
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p2->prev->next = p2->next;
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else
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this->first = p2->next;
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if (p2->next)
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p2->next->prev = p2->prev;
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else
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this->last = p2->prev;
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p2->next = NULL;
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p2->prev = NULL;
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p2->inuse = 1;
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*member = p2;
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/*ippool_printaddr(this);*/
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return 0; /* Success */
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}
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int ippool_freeip(struct ippoolm_t *member) {
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struct ippool_t *this = member->parent;
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/*ippool_printaddr(this);*/
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if (!member->inuse) return -1; /* Not in use: Should not happen */
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/* Insert into list of unused */
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member->prev = this->last;
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if (this->last) {
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this->last->next = member;
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}
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else {
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this->first = member;
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}
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this->last = member;
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member->inuse = 0;
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/*ippool_printaddr(this);*/
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return 0; /* Success */
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}
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#ifndef IPPOOL_NOIP6
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extern unsigned long int ippool_hash6(struct in6_addr *addr);
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extern int ippool_getip6(struct ippool_t *this, struct in6_addr *addr);
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extern int ippool_returnip6(struct ippool_t *this, struct in6_addr *addr);
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#endif
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