diff --git a/ggsn/ippool.c b/ggsn/ippool.c
new file mode 100644
index 0000000..3ad5c04
--- /dev/null
+++ b/ggsn/ippool.c
@@ -0,0 +1,416 @@
+/* 
+ * IP address pool functions.
+ * Copyright (C) 2003 Mondru AB.
+ * 
+ * The contents of this file may be used under the terms of the GNU
+ * General Public License Version 2, provided that the above copyright
+ * notice and this permission notice is included in all copies or
+ * substantial portions of the software.
+ * 
+ * The initial developer of the original code is
+ * Jens Jakobsen <jj@openggsn.org>
+ * 
+ * Contributor(s):
+ * 
+ */
+
+#include <netinet/in.h> /* in_addr */
+#include <stdlib.h>     /* calloc */
+#include <stdio.h>      /* sscanf */
+
+#include "ippool.h"
+
+
+/*
+--------------------------------------------------------------------
+Public domain by From Bob Jenkins, December 1996.
+mix -- mix 3 32-bit values reversibly.
+For every delta with one or two bit set, and the deltas of all three
+  high bits or all three low bits, whether the original value of a,b,c
+  is almost all zero or is uniformly distributed,
+* If mix() is run forward or backward, at least 32 bits in a,b,c
+  have at least 1/4 probability of changing.
+* If mix() is run forward, every bit of c will change between 1/3 and
+  2/3 of the time.  (Well, 22/100 and 78/100 for some 2-bit deltas.)
+mix() was built out of 36 single-cycle latency instructions in a 
+  structure that could supported 2x parallelism, like so:
+      a -= b; 
+      a -= c; x = (c>>13);
+      b -= c; a ^= x;
+      b -= a; x = (a<<8);
+      c -= a; b ^= x;
+      c -= b; x = (b>>13);
+      ...
+  Unfortunately, superscalar Pentiums and Sparcs can't take advantage 
+  of that parallelism.  They've also turned some of those single-cycle
+  latency instructions into multi-cycle latency instructions.  Still,
+  this is the fastest good hash I could find.  There were about 2^^68
+  to choose from.  I only looked at a billion or so.
+--------------------------------------------------------------------
+*/
+#define mix(a,b,c) \
+{ \
+  a -= b; a -= c; a ^= (c>>13); \
+  b -= c; b -= a; b ^= (a<<8); \
+  c -= a; c -= b; c ^= (b>>13); \
+  a -= b; a -= c; a ^= (c>>12);  \
+  b -= c; b -= a; b ^= (a<<16); \
+  c -= a; c -= b; c ^= (b>>5); \
+  a -= b; a -= c; a ^= (c>>3);  \
+  b -= c; b -= a; b ^= (a<<10); \
+  c -= a; c -= b; c ^= (b>>15); \
+}
+/*
+--------------------------------------------------------------------
+lookup() -- hash a variable-length key into a 32-bit value
+  k     : the key (the unaligned variable-length array of bytes)
+  len   : the length of the key, counting by bytes
+  level : can be any 4-byte value
+Returns a 32-bit value.  Every bit of the key affects every bit of
+the return value.  Every 1-bit and 2-bit delta achieves avalanche.
+About 6len+35 instructions.
+
+The best hash table sizes are powers of 2.  There is no need to do
+mod a prime (mod is sooo slow!).  If you need less than 32 bits,
+use a bitmask.  For example, if you need only 10 bits, do
+  h = (h & hashmask(10));
+In which case, the hash table should have hashsize(10) elements.
+
+If you are hashing n strings (ub1 **)k, do it like this:
+  for (i=0, h=0; i<n; ++i) h = lookup( k[i], len[i], h);
+
+By Bob Jenkins, 1996.  bob_jenkins@burtleburtle.net.  You may use this
+code any way you wish, private, educational, or commercial.
+
+See http://burtleburtle.net/bob/hash/evahash.html
+Use for hash table lookup, or anything where one collision in 2^32 is
+acceptable.  Do NOT use for cryptographic purposes.
+--------------------------------------------------------------------
+*/
+
+unsigned long int lookup( k, length, level)
+register unsigned char *k;           /* the key */
+register unsigned long int length;   /* the length of the key */
+register unsigned long int level;    /* the previous hash, or an arbitrary value */
+{
+   register unsigned long int a,b,c,len;
+
+   /* Set up the internal state */
+   len = length;
+   a = b = 0x9e3779b9;  /* the golden ratio; an arbitrary value */
+   c = level;           /* the previous hash value */
+
+   /*---------------------------------------- handle most of the key */
+   while (len >= 12)
+   {
+      a += (k[0] +((ub4)k[1]<<8) +((ub4)k[2]<<16) +((ub4)k[3]<<24));
+      b += (k[4] +((ub4)k[5]<<8) +((ub4)k[6]<<16) +((ub4)k[7]<<24));
+      c += (k[8] +((ub4)k[9]<<8) +((ub4)k[10]<<16)+((ub4)k[11]<<24));
+      mix(a,b,c);
+      k += 12; len -= 12;
+   }
+
+   /*------------------------------------- handle the last 11 bytes */
+   c += length;
+   switch(len)              /* all the case statements fall through */
+   {
+   case 11: c+=((ub4)k[10]<<24);
+   case 10: c+=((ub4)k[9]<<16);
+   case 9 : c+=((ub4)k[8]<<8);
+      /* the first byte of c is reserved for the length */
+   case 8 : b+=((ub4)k[7]<<24);
+   case 7 : b+=((ub4)k[6]<<16);
+   case 6 : b+=((ub4)k[5]<<8);
+   case 5 : b+=k[4];
+   case 4 : a+=((ub4)k[3]<<24);
+   case 3 : a+=((ub4)k[2]<<16);
+   case 2 : a+=((ub4)k[1]<<8);
+   case 1 : a+=k[0];
+     /* case 0: nothing left to add */
+   }
+   mix(a,b,c);
+   /*-------------------------------------------- report the result */
+   return c;
+}
+
+/*
+End of public domain code by From Bob Jenkins, December 1996.
+--------------------------------------------------------------------
+*/
+
+int ippool_printaddr(struct ippool_t *this) {
+  int n;
+  printf("ippool_printaddr\n");
+  printf("First %d\n", this->first - this->member);
+  printf("Last %d\n",  this->last - this->member);
+  printf("Listsize %d\n",  this->listsize);
+
+  for (n=0; n<this->listsize; n++) {
+    printf("Unit %d inuse %d prev %d next %d addr %x\n", 
+	   n,
+	   this->member[n].inuse,
+	   this->member[n].prev - this->member,
+	   this->member[n].next - this->member,
+	   this->member[n].addr.s_addr
+	   );
+  }
+  return 0;
+}
+
+
+unsigned long int ippool_hash4(struct in_addr *addr) {
+  return lookup(&addr->s_addr, sizeof(addr->s_addr), 0);
+}
+
+#ifndef IPPOOL_NOIP6
+unsigned long int ippool_hash6(struct in6_addr *addr) {
+  return lookup(addr->u6_addr8, sizeof(addr->u6_addr8), 0);
+}
+#endif
+
+
+/* Get IP address and mask */
+int ippool_aton(struct in_addr *addr, struct in_addr *mask,
+		char *pool, int number) {
+
+  /* Parse only first instance of network for now */
+  /* Eventually "number" will indicate the token which we want to parse */
+
+  unsigned int a1, a2, a3, a4;
+  unsigned int m1, m2, m3, m4;
+  int c;
+  unsigned int m;
+  int masklog;
+
+  c = sscanf(pool, "%u.%u.%u.%u/%u.%u.%u.%u",
+	     &a1, &a2, &a3, &a4,
+	     &m1, &m2, &m3, &m4);
+  switch (c) {
+  case 4:
+    if (a1 == 0 && a2 == 0 && a3 == 0 && a4 == 0) /* Full Internet */
+      mask->s_addr = 0x00000000;
+    else if (a2 == 0 && a3 == 0 && a4 == 0)       /* class A */
+      mask->s_addr = htonl(0xff000000);
+    else if (a3 == 0 && a4 == 0)	          /* class B */
+      mask->s_addr = htonl(0xffff0000);
+    else if (a4 == 0)	                          /* class C */
+      mask->s_addr = htonl(0xffffff00);
+    else
+      mask->s_addr = 0xffffffff;
+    break;
+  case 5:
+    if (m1 < 0 || m1 > 32) {
+      return -1; /* Invalid mask */
+    }
+    mask->s_addr = htonl(0xffffffff << (32 - m1));
+    break;
+  case 8:
+    if (m1 >= 256 ||  m2 >= 256 || m3 >= 256 || m4 >= 256)
+      return -1; /* Wrong mask format */
+    m = m1 * 0x1000000 + m2 * 0x10000 + m3 * 0x100 + m4;
+    for (masklog = 0; ((1 << masklog) < ((~m)+1)); masklog++);
+    if (((~m)+1) != (1 << masklog))
+      return -1; /* Wrong mask format (not all ones followed by all zeros)*/
+    mask->s_addr = htonl(m);
+    break;
+  default:
+    return -1; /* Invalid mask */
+  }
+
+  if (a1 >= 256 ||  a2 >= 256 || a3 >= 256 || a4 >= 256)
+    return -1; /* Wrong IP address format */
+  else
+    addr->s_addr = htonl(a1 * 0x1000000 + a2 * 0x10000 + a3 * 0x100 + a4);
+
+  return 0;
+}
+
+/* Create new address pool */
+int ippool_new(struct ippool_t **this, char *pool, int flags) {
+
+  /* Parse only first instance of network for now */
+
+  int i;
+  struct ippoolm_t *p;
+  struct ippoolm_t *p_prev = NULL; 
+  uint32_t hash;
+  struct in_addr addr;
+  struct in_addr mask;
+  unsigned int m;
+  unsigned int listsize;
+
+  if (ippool_aton(&addr, &mask, pool, 0))
+    return 0; /* Failed to parse pool */
+
+  m = ntohl(mask.s_addr);
+  listsize = ((~m)+1);
+  if (flags & IPPOOL_NONETWORK)   /* Exclude network address from pool */
+    listsize--;
+  if (flags & IPPOOL_NOBROADCAST) /* Exclude broadcast address from pool */
+    listsize--;
+
+  if (!(*this = calloc(sizeof(struct ippool_t), 1))) {
+    /* Failed to allocate memory for ippool */
+    return -1;
+  }
+  
+  (*this)->listsize += listsize;
+  if (!((*this)->member = calloc(sizeof(struct ippoolm_t), (*this)->listsize))){
+    /* Failed to allocate memory for members in ippool */
+    return -1;
+  }
+  
+  for ((*this)->hashlog = 0; 
+       ((1 << (*this)->hashlog) < listsize);
+       (*this)->hashlog++);
+
+  /*   printf ("Hashlog %d %d %d\n", (*this)->hashlog, listsize, (1 << (*this)->hashlog)); */
+
+  /* Determine hashsize */
+  (*this)->hashsize = 1 << (*this)->hashlog; /* Fails if mask=0: All Internet*/
+  (*this)->hashmask = (*this)->hashsize -1;
+  
+  /* Allocate hash table */
+  if (!((*this)->hash = calloc(sizeof(struct ippoolm_t), (*this)->hashsize))){
+    /* Failed to allocate memory for hash members in ippool */
+    return -1;
+  }
+  
+  (*this)->first = NULL;
+  (*this)->last = NULL;
+  for (i = 0; i<(*this)->listsize; i++) {
+
+    if (flags & IPPOOL_NONETWORK)
+      (*this)->member[i].addr.s_addr = htonl(ntohl(addr.s_addr) + i + 1);
+    else
+      (*this)->member[i].addr.s_addr = htonl(ntohl(addr.s_addr) + i);
+
+    (*this)->member[i].inuse = 0;
+    (*this)->member[i].parent = *this;
+
+    /* Insert into list of unused */
+    (*this)->member[i].prev = (*this)->last;
+    if ((*this)->last) {
+      (*this)->last->next = &((*this)->member[i]);
+    }
+    else {
+      (*this)->first = &((*this)->member[i]);
+    }
+    (*this)->last = &((*this)->member[i]);
+    (*this)->member[i].next = NULL; /* Redundant */
+
+    /* Insert into hash table */
+    hash = ippool_hash4(&(*this)->member[i].addr) & (*this)->hashmask;
+    for (p = (*this)->hash[hash]; p; p = p->nexthash)
+      p_prev = p;
+    if (!p_prev)
+      (*this)->hash[hash] = &((*this)->member[i]);
+    else 
+      p_prev->nexthash = &((*this)->member[i]);
+  }
+  /*ippool_printaddr(*this);*/
+  return 0;
+}
+
+/* Delete existing address pool */
+int ippool_free(struct ippool_t *this) {
+  free(this->hash);
+  free(this->member);
+  free(this);
+  return 0; /* Always OK */
+}
+
+/* Find an IP address in the pool */
+int ippool_getip(struct ippool_t *this, struct ippoolm_t **member,
+		 struct in_addr *addr) {
+  struct ippoolm_t *p;
+  uint32_t hash;
+
+  /* Find in hash table */
+  hash = ippool_hash4(addr) & this->hashmask;
+  for (p = this->hash[hash]; p; p = p->nexthash) {
+    if ((p->addr.s_addr == addr->s_addr) && (p->inuse)) {
+      *member = p;
+      return 0;
+    }
+  }
+  *member = NULL;
+  return -1; /* Address could not be found */
+}
+
+
+/* Get an IP address. If addr = 0.0.0.0 get a dynamic IP address. Otherwise
+   check to see if the given address is available */
+int ippool_newip(struct ippool_t *this, struct ippoolm_t **member,
+		 struct in_addr *addr) {
+  struct ippoolm_t *p;
+  struct ippoolm_t *p2 = NULL;
+  uint32_t hash;
+
+  /*ippool_printaddr(this);*/
+
+  if ((addr) && (addr->s_addr)) { /* IP address given */
+    /* Find in hash table */
+    hash = ippool_hash4(addr) & this->hashmask;
+    for (p = this->hash[hash]; p; p = p->nexthash) {
+      if ((p->addr.s_addr == addr->s_addr)) {
+	p2 = p;
+	break;
+      }
+    }
+  }
+  else { /* No ip address given */
+    p2 = this -> first;
+  }
+
+  if (!p2) return -1; /* Not found */
+  if (p2->inuse) return -1; /* Allready in use / Should not happen */
+  
+  /* Found new address. Remove from queue */
+  if (p2->prev) 
+    p2->prev->next = p2->next;
+  else
+    this->first = p2->next;
+  if (p2->next) 
+    p2->next->prev = p2->prev;
+  else
+    this->last = p2->prev;
+  p2->next = NULL;
+  p2->prev = NULL;
+  p2->inuse = 1;
+  
+  *member = p2;
+  /*ippool_printaddr(this);*/
+  return 0; /* Success */
+}
+
+
+int ippool_freeip(struct ippoolm_t *member) {
+  struct ippool_t *this = member->parent;
+  
+  /*ippool_printaddr(this);*/
+
+  if (!member->inuse) return -1; /* Not in use: Should not happen */
+
+  /* Insert into list of unused */
+  member->prev = this->last;
+  if (this->last) {
+    this->last->next = member;
+  }
+  else {
+    this->first = member;
+  }
+  this->last = member;
+
+  member->inuse = 0;
+  /*ippool_printaddr(this);*/
+  
+  return 0; /* Success */
+}
+
+
+#ifndef IPPOOL_NOIP6
+extern unsigned long int ippool_hash6(struct in6_addr *addr);
+extern int ippool_getip6(struct ippool_t *this, struct in6_addr *addr);
+extern int ippool_returnip6(struct ippool_t *this, struct in6_addr *addr);
+#endif