/*
 *
 * IP address pool functions.
 * Copyright (C) 2003, 2004, 2005 Mondru AB.
 * Copyright (c) 2006-2007 David Bird <david@coova.com>
 *
 * 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.
 * 
 */

#include "system.h"
#include "syserr.h"
#include "radius.h"
#include "md5.h"
#include "dhcp.h"
#include "redir.h"
#include "ippool.h"
#include "lookup.h"
#include "chilli.h"
#include "options.h"

const unsigned int IPPOOL_STATSIZE = 0x10000;

int ippool_printaddr(struct ippool_t *this) {
  int n;
  printf("ippool_printaddr\n");
  printf("Firstdyn %d\n", this->firstdyn - this->member);
  printf("Lastdyn %d\n",  this->lastdyn - this->member);
  printf("Firststat %d\n", this->firststat - this->member);
  printf("Laststat %d\n",  this->laststat - 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 %s %x\n", 
	   n,
	   this->member[n].inuse,
	   this->member[n].prev - this->member,
	   this->member[n].next - this->member,
	   inet_ntoa(this->member[n].addr),	
	   this->member[n].addr.s_addr
	   );
  }
  return 0;
}

int ippool_hashadd(struct ippool_t *this, struct ippoolm_t *member) {
  uint32_t hash;
  struct ippoolm_t *p;
  struct ippoolm_t *p_prev = NULL; 

  /* Insert into hash table */
  hash = ippool_hash4(&member->addr) & this->hashmask;

  for (p = this->hash[hash]; p; p = p->nexthash)
    p_prev = p;

  if (!p_prev)
    this->hash[hash] = member;
  else 
    p_prev->nexthash = member;

  return 0; /* Always OK to insert */
}

int ippool_hashdel(struct ippool_t *this, struct ippoolm_t *member) {
  uint32_t hash;
  struct ippoolm_t *p;
  struct ippoolm_t *p_prev = NULL; 

  /* Find in hash table */
  hash = ippool_hash4(&member->addr) & this->hashmask;
  for (p = this->hash[hash]; p; p = p->nexthash) {
    if (p == member) {
      break;
    }
    p_prev = p;
  }

  if (p!= member) {
    log_err(0, "ippool_hashdel: Tried to delete member not in hash table");
    return -1;
  }

  if (!p_prev)
    this->hash[hash] = p->nexthash;
  else
    p_prev->nexthash = p->nexthash;

  return 0;
}

uint32_t ippool_hash4(struct in_addr *addr) {
  return lookup((unsigned char *)&addr->s_addr, sizeof(addr->s_addr), 0);
}

#ifndef IPPOOL_NOIP6
uint32_t ippool_hash6(struct in6_addr *addr) {
  return lookup((unsigned char *)addr->u6_addr8, sizeof(addr->u6_addr8), 0);
}
#endif

/* Create new address pool */
int ippool_new(struct ippool_t **this, 
	       char *dyn, int start, int end, char *stat, 
	       int allowdyn, int allowstat) {

  /* Parse only first instance of pool for now */

  int i;
  struct in_addr addr;
  struct in_addr mask;
  struct in_addr stataddr;
  struct in_addr statmask;
  struct in_addr naddr;
  unsigned int m;
  unsigned int listsize;
  unsigned int dynsize;
  unsigned int statsize;

  if (!allowdyn) {
    dynsize = 0;
  }
  else {
    if (option_aton(&addr, &mask, dyn, 0)) {
      log_err(0, "Failed to parse dynamic pool");
      return -1;
    }

    m = ntohl(mask.s_addr);
    dynsize = ((~m)+1); 

    if (start > 0 && end > 0) {

      if (end < start) {
	log_err(0, "Bad arguments dhcpstart=%d and dhcpend=%d", start, end);
	return -1;
      }

      if ((end - start) > dynsize) {
	log_err(0, "Too many IPs between dhcpstart=%d and dhcpend=%d for network", start, end);
	return -1;
      }

      dynsize = end - start;

    } else {

      if (start > 0) {

	/*
	 * if only dhcpstart is set, subtract that from count
	 */
	dynsize -= start;

	dynsize--;/* no broadcast */

      } else if (end > 0) {

	/*
	 * if only dhcpend is set, ensure only that many
	 */
	if (dynsize > end)
	  dynsize = end;

	dynsize--;/* no network */

      } else {
	dynsize-=2;/* no network, no broadcast */
      }

      dynsize--;/* no uamlisten */
    }
  }

  if (!allowstat) {
    statsize = 0;
    stataddr.s_addr = 0;
    statmask.s_addr = 0;
  }
  else {
    if (option_aton(&stataddr, &statmask, stat, 0)) {
      log_err(0, "Failed to parse static range");
      return -1;
    }

    m = ntohl(statmask.s_addr);
    statsize = ((~m)+1);

    if (statsize > IPPOOL_STATSIZE)
      statsize = IPPOOL_STATSIZE;
  }

  listsize = dynsize + statsize; /* Allocate space for static IP addresses */

  if (!(*this = calloc(sizeof(struct ippool_t), 1))) {
    log_err(0, "Failed to allocate memory for ippool");
    return -1;
  }
  
  (*this)->allowdyn  = allowdyn;
  (*this)->allowstat = allowstat;
  (*this)->stataddr  = stataddr;
  (*this)->statmask  = statmask;

  (*this)->listsize += listsize;
  if (!((*this)->member = calloc(sizeof(struct ippoolm_t), listsize))){
    log_err(0, "Failed to allocate memory for members in ippool");
    return -1;
  }
  
  for ((*this)->hashlog = 0; 
       ((1 << (*this)->hashlog) < listsize);
       (*this)->hashlog++);

  log_dbg("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))){
    log_err(0, "Failed to allocate memory for hash members in ippool");
    return -1;
  }

  if (start <= 0) /* adjust for skipping network */
    start = 1; 
  
  (*this)->firstdyn = NULL;
  (*this)->lastdyn = NULL;
  for (i = 0; i<dynsize; i++) {

    naddr.s_addr = htonl(ntohl(addr.s_addr) + i + start);
    if (naddr.s_addr == options.uamlisten.s_addr) {
      start++; /* skip the uamlisten address! */
      naddr.s_addr = htonl(ntohl(addr.s_addr) + i + start);
    }

    (*this)->member[i].addr.s_addr = naddr.s_addr;
    (*this)->member[i].inuse = 0;

    /* Insert into list of unused */
    (*this)->member[i].prev = (*this)->lastdyn;
    if ((*this)->lastdyn) {
      (*this)->lastdyn->next = &((*this)->member[i]);
    }
    else {
      (*this)->firstdyn = &((*this)->member[i]);
    }
    (*this)->lastdyn = &((*this)->member[i]);
    (*this)->member[i].next = NULL; /* Redundant */

    ippool_hashadd(*this, &(*this)->member[i]);
  }

  (*this)->firststat = NULL;
  (*this)->laststat = NULL;
  for (i = dynsize; i<listsize; i++) {
    (*this)->member[i].addr.s_addr = 0;
    (*this)->member[i].inuse = 0;

    /* Insert into list of unused */
    (*this)->member[i].prev = (*this)->laststat;
    if ((*this)->laststat) {
      (*this)->laststat->next = &((*this)->member[i]);
    }
    else {
      (*this)->firststat = &((*this)->member[i]);
    }
    (*this)->laststat = &((*this)->member[i]);
    (*this)->member[i].next = NULL; /* Redundant */
  }
  
  if (0) 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)) {
      if (member) *member = p;
      return 0;
    }
  }

  if (member) *member = NULL;
  return -1;
}

/**
 * ippool_newip
 * 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. If available within
 * dynamic address space allocate it there, otherwise allocate within static
 * address space.
**/
int ippool_newip(struct ippool_t *this, struct ippoolm_t **member,
		 struct in_addr *addr, int statip) {
  struct ippoolm_t *p;
  struct ippoolm_t *p2 = NULL;
  uint32_t hash;

  log_dbg("Requesting new %s ip: %s", statip ? "static" : "dynamic", inet_ntoa(*addr));

  /* If static:
   *   Look in dynaddr. 
   *     If found remove from firstdyn/lastdyn linked list.
   *   Else allocate from stataddr.
   *    Remove from firststat/laststat linked list.
   *    Insert into hash table.
   *
   * If dynamic
   *   Remove from firstdyn/lastdyn linked list.
   *
   */

  /*if(0)(void)ippool_printaddr(this);*/

  /* First check to see if this type of address is allowed */
  if ((addr) && (addr->s_addr) && statip) { /* IP address given */
    if (!options.uamanyip) {
      if (!this->allowstat) {
	log_dbg("Static IP address not allowed");
	return -1;
      }
      if ((addr->s_addr & this->statmask.s_addr) != this->stataddr.s_addr) {
	log_err(0, "Static out of range");
	return -1;
      }
    }
  }
  else {
    if (!this->allowdyn) {
      log_err(0, "Dynamic IP address not allowed");
      return -1; 
    }
  }

  /* If IP address given try to find it in address pool */
  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;
      }
    }
  }

  /* if anyip is set and statip return the same ip */
  if (statip && options.uamanyip && p2 && p2->inuse == 2) {
    log_dbg("Found already allocated static ip");
    *member = p2;
    return 0;
  }

  /* If IP was already allocated we can not use it */
  if ((!statip) && (p2) && (p2->inuse)) {
    p2 = NULL; 
  }

  /* If not found yet and dynamic IP then allocate dynamic IP */
  if ((!p2) && (!statip) /*XXX: && (!addr || !addr->s_addr)*/) {
    if (!this->firstdyn) {
      log_err(0, "No more IP addresses available");
      return -1;
    }
    else
      p2 = this->firstdyn;
  }
  
  if (p2) { /* Was allocated from dynamic address pool */
    if (p2->inuse) {
      log_err(0, "IP address allready in use");
      return -1; /* Allready in use / Should not happen */
    }

    /* Remove from linked list of free dynamic addresses */
    if (p2->prev) 
      p2->prev->next = p2->next;
    else
      this->firstdyn = p2->next;

    if (p2->next) 
      p2->next->prev = p2->prev;
    else
      this->lastdyn = p2->prev;

    p2->next = NULL;
    p2->prev = NULL;
    p2->inuse = 1; /* Dynamic address in use */
    
    *member = p2;
    if (0) (void)ippool_printaddr(this);
    return 0; /* Success */
  }

  /* It was not possible to allocate from dynamic address pool */
  /* Try to allocate from static address space */

  if ((addr) && (addr->s_addr) && (statip||options.uamanyip)) { /* IP address given */
    if (!this->firststat) {
      log_err(0, "No more IP addresses available");
      return -1; /* No more available */
    }
    else
      p2 = this->firststat;

    /* Remove from linked list of free static addresses */
    if (p2->prev) 
      p2->prev->next = p2->next;
    else
      this->firststat = p2->next;

    if (p2->next) 
      p2->next->prev = p2->prev;
    else
      this->laststat = p2->prev;

    p2->next = NULL;
    p2->prev = NULL;
    p2->inuse = 2; /* Static address in use */
    memcpy(&p2->addr, addr, sizeof(addr));
    *member = p2;

    log_dbg("Assigned a static ip to: %s", inet_ntoa(*addr));

    ippool_hashadd(this, *member);

    if (0) (void)ippool_printaddr(this);
    return 0; /* Success */
  }

  return -1; 
}


int ippool_freeip(struct ippool_t *this, struct ippoolm_t *member) {
  
  if (0) ippool_printaddr(this);

  if (!member->inuse) {
    log_err(0, "Address not in use");
    return -1; /* Not in use: Should not happen */
  }

  switch (member->inuse) {

  case 0: /* Not in use: Should not happen */
    log_err(0, "Address not in use");
    return -1;

  case 1: /* Allocated from dynamic address space */
    /* Insert into list of unused */
    member->prev = this->lastdyn;

    if (this->lastdyn) {
      this->lastdyn->next = member;
    }
    else {
      this->firstdyn = member;
    }

    this->lastdyn = member;
    
    member->inuse = 0;
    member->peer = NULL;
    if (0) (void)ippool_printaddr(this);
    return 0;

  case 2: /* Allocated from static address space */
    if (ippool_hashdel(this, member))
      return -1;

    /* Insert into list of unused */
    member->prev = this->laststat;

    if (this->laststat) {
      this->laststat->next = member;
    }
    else {
      this->firststat = member;
    }

    this->laststat = member;
    
    member->inuse = 0;
    member->addr.s_addr = 0;
    member->peer = NULL;
    member->nexthash = NULL;
    if (0) (void)ippool_printaddr(this);
    return 0;

  default: /* Should not happen */
    log_err(0, "Could not free IP address");
    return -1;
  }
}


#ifndef IPPOOL_NOIP6
extern uint32_t 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