/*	$OpenBSD: isakmp_cfg.c,v 1.23 2003/01/09 12:46:45 ho Exp $	*/

/*
 * Copyright (c) 2001 Niklas Hallqvist.  All rights reserved.
 * Copyright (c) 2002 Håkan Olsson.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Ericsson Radio Systems.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This code was written under funding by Gatespace
 * (http://www.gatespace.com/).
 */

#include <sys/types.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <bitstring.h>

#include "sysdep.h"

#include "attribute.h"
#include "conf.h"
#include "exchange.h"
#include "hash.h"
#include "ipsec.h"
#include "isakmp_fld.h"
#include "isakmp_num.h"
#include "log.h"
#include "message.h"
#include "prf.h"
#include "sa.h"
#include "transport.h"
#include "util.h"

/*
 * Validation script used to test messages for correct content of
 * payloads depending on the exchange type.
 */
int16_t script_transaction[] = {
  ISAKMP_PAYLOAD_ATTRIBUTE,	/* Initiator -> responder.  */
  EXCHANGE_SCRIPT_SWITCH,
  ISAKMP_PAYLOAD_ATTRIBUTE,	/* Responder -> initiator.  */
  EXCHANGE_SCRIPT_END
};

static int cfg_decode_attribute (u_int16_t, u_int8_t *, u_int16_t, void *);
static int cfg_encode_attributes (struct isakmp_cfg_attr_head *, u_int32_t,
				  u_int32_t, char *, u_int8_t **, u_int16_t *);
static int cfg_initiator_send_ATTR (struct message *);
static int cfg_initiator_recv_ATTR (struct message *);
static int cfg_responder_recv_ATTR (struct message *);
static int cfg_responder_send_ATTR (struct message *);

u_int8_t *cfg_add_hash (struct message *);
int	  cfg_finalize_hash (struct message *,u_int8_t *, u_int8_t *,
			     u_int16_t);
int	  cfg_verify_hash (struct message *msg);

/* Server: SET/ACK    Client; REQ/REPLY */
int (*isakmp_cfg_initiator[]) (struct message *) = {
  cfg_initiator_send_ATTR,
  cfg_initiator_recv_ATTR
};

/* Server: REQ/REPLY  Client: SET/ACK */
int (*isakmp_cfg_responder[]) (struct message *) = {
  cfg_responder_recv_ATTR,
  cfg_responder_send_ATTR
};

/*
 * When we are "the server", this starts SET/ACK mode
 * When we are "the client", this starts REQ/REPLY mode
 */
static int
cfg_initiator_send_ATTR (struct message *msg)
{
  struct sa *isakmp_sa = msg->isakmp_sa;
  struct ipsec_exch *ie = msg->exchange->data;
  u_int8_t *hashp = 0, *attrp, *attr;
  size_t attrlen, off;
  char *id_string, *cfg_mode, *field;
  struct sockaddr *sa;
#define CFG_ATTR_BIT_MAX ISAKMP_CFG_ATTR_FUTURE_MIN	/* XXX */
  bitstr_t bit_decl (attrbits, CFG_ATTR_BIT_MAX);
  u_int16_t bit, length;
  u_int32_t life;

  if (msg->exchange->phase == 2)
    {
      hashp = cfg_add_hash (msg);
      if (!hashp)
	return -1;
    }

  /* We inititated of this exchange, check isakmp_sa for other side.  */
  if (isakmp_sa->initiator)
    id_string = ipsec_id_string (isakmp_sa->id_r, isakmp_sa->id_r_len);
  else
    id_string = ipsec_id_string (isakmp_sa->id_i, isakmp_sa->id_i_len);
  if (!id_string)
    {
      log_print ("cfg_initiator_send_ATTR: cannot parse ID");
      goto fail;
    }

  /* Check for attribute list to send to the other side */
  attrlen = 0;
  bit_nclear (attrbits, 0, CFG_ATTR_BIT_MAX - 1);

  cfg_mode = conf_get_str (id_string, "Mode");
  if (!cfg_mode || strcmp (cfg_mode, "SET") == 0)
    {
      /* SET/ACK mode */
      ie->cfg_type = ISAKMP_CFG_SET;

      LOG_DBG ((LOG_NEGOTIATION, 10, "cfg_initiator_send_ATTR: SET/ACK mode"));

#define ATTRFIND(STR,ATTR4,LEN4,ATTR6,LEN6) do				\
	{								\
	  if ((sa = conf_get_address (id_string, STR)) != NULL)		\
	    switch (sa->sa_family)					\
	      {								\
	      case AF_INET:						\
		bit_set (attrbits, ATTR4);				\
		attrlen += ISAKMP_ATTR_SZ + LEN4;		       	\
		break;							\
	      case AF_INET6:						\
		bit_set (attrbits, ATTR6);				\
		attrlen += ISAKMP_ATTR_SZ + LEN6;			\
		break;							\
	      default:							\
		break;							\
	      }								\
          free (sa);							\
        } while (0)

      /* XXX We don't simultaneously support IPv4 and IPv6 addresses.  */
      ATTRFIND ("Address", ISAKMP_CFG_ATTR_INTERNAL_IP4_ADDRESS, 4,
		ISAKMP_CFG_ATTR_INTERNAL_IP6_ADDRESS, 16);
      ATTRFIND ("Netmask", ISAKMP_CFG_ATTR_INTERNAL_IP4_NETMASK, 4,
		ISAKMP_CFG_ATTR_INTERNAL_IP6_NETMASK, 16);
      ATTRFIND ("Nameserver", ISAKMP_CFG_ATTR_INTERNAL_IP4_DNS, 4,
		ISAKMP_CFG_ATTR_INTERNAL_IP6_DNS, 16);
      ATTRFIND ("WINS-server", ISAKMP_CFG_ATTR_INTERNAL_IP4_NBNS, 4,
		ISAKMP_CFG_ATTR_INTERNAL_IP6_NBNS, 16);
      ATTRFIND ("DHCP-server", ISAKMP_CFG_ATTR_INTERNAL_IP4_DHCP, 4,
		ISAKMP_CFG_ATTR_INTERNAL_IP6_DHCP, 16);
#ifdef notyet
      ATTRFIND ("Network", ISAKMP_CFG_ATTR_INTERNAL_IP4_SUBNET, 8,
		ISAKMP_CFG_ATTR_INTERNAL_IP6_SUBNET, 17);
#endif
#undef ATTRFIND

      if (conf_get_str (id_string, "Lifetime"))
	{
	  bit_set (attrbits, ISAKMP_CFG_ATTR_INTERNAL_ADDRESS_EXPIRY);
	  attrlen += ISAKMP_ATTR_SZ + 4;
	}
    }
  else
    {
      struct conf_list *alist;
      struct conf_list_node *anode;

      ie->cfg_type = ISAKMP_CFG_REQUEST;

      LOG_DBG ((LOG_NEGOTIATION, 10,
		"cfg_initiator_send_ATTR: REQ/REPLY mode"));

      alist = conf_get_list (id_string, "Attributes");
      if (alist)
	{
	  for (anode = TAILQ_FIRST (&alist->fields); anode;
	       anode = TAILQ_NEXT (anode, link))
	    {
	      if (strcasecmp (anode->field, "Address") == 0)
		{
		  bit_set (attrbits, ISAKMP_CFG_ATTR_INTERNAL_IP4_ADDRESS);
		  bit_set (attrbits, ISAKMP_CFG_ATTR_INTERNAL_IP6_ADDRESS);
		  attrlen += ISAKMP_ATTR_SZ * 2;
		}
	      else if (strcasecmp (anode->field, "Netmask") == 0)
		{
		  bit_set (attrbits, ISAKMP_CFG_ATTR_INTERNAL_IP4_NETMASK);
		  bit_set (attrbits, ISAKMP_CFG_ATTR_INTERNAL_IP6_NETMASK);
		  attrlen += ISAKMP_ATTR_SZ * 2;
		}
	      else if (strcasecmp (anode->field, "Nameserver") == 0)
		{
		  bit_set (attrbits, ISAKMP_CFG_ATTR_INTERNAL_IP4_DNS);
		  bit_set (attrbits, ISAKMP_CFG_ATTR_INTERNAL_IP6_DNS);
		  attrlen += ISAKMP_ATTR_SZ * 2;
		}
	      else if (strcasecmp (anode->field, "WINS-server") == 0)
		{
		  bit_set (attrbits, ISAKMP_CFG_ATTR_INTERNAL_IP4_NBNS);
		  bit_set (attrbits, ISAKMP_CFG_ATTR_INTERNAL_IP6_NBNS);
		  attrlen += ISAKMP_ATTR_SZ * 2;
		}
	      else if (strcasecmp (anode->field, "DHCP-server") == 0)
		{
		  bit_set (attrbits, ISAKMP_CFG_ATTR_INTERNAL_IP4_DHCP);
		  bit_set (attrbits, ISAKMP_CFG_ATTR_INTERNAL_IP6_DHCP);
		  attrlen += ISAKMP_ATTR_SZ * 2;
		}
	      else if (strcasecmp (anode->field, "Lifetime") == 0)
		{
		  bit_set (attrbits, ISAKMP_CFG_ATTR_INTERNAL_ADDRESS_EXPIRY);
		  attrlen += ISAKMP_ATTR_SZ;
		}
	      else
		{
		  log_print ("cfg_initiator_send_ATTR: unknown attribute "
			     "%.20s in section [%s]", anode->field, id_string);
		}
	    }

	  conf_free_list (alist);
	}
    }

  if (attrlen == 0)
    {
      /* No data found.  */
      log_print ("cfg_initiator_send_ATTR: no IKECFG attributes "
		 "found for [%s]", id_string);

      /*
       * We can continue, but this indicates a configuration error that
       * the user probably will want to correct.
       */
      free (id_string);
      return 0;
    }

  attrlen += ISAKMP_ATTRIBUTE_SZ;
  attrp = calloc (1, attrlen);
  if (!attrp)
    {
      log_error ("cfg_initiator_send_ATTR: calloc (1, %lu) failed",
		 (unsigned long)attrlen);
      goto fail;
    }

  if (message_add_payload (msg, ISAKMP_PAYLOAD_ATTRIBUTE, attrp, attrlen, 1))
    {
      free (attrp);
      goto fail;
    }

  SET_ISAKMP_ATTRIBUTE_TYPE (attrp, ie->cfg_type);
  getrandom ((u_int8_t *)&ie->cfg_id, sizeof ie->cfg_id);
  SET_ISAKMP_ATTRIBUTE_ID (attrp, ie->cfg_id);

  off = ISAKMP_ATTRIBUTE_SZ;

  /*
   * Use the bitstring built previously to collect the right
   * parameters for attrp.
   */
  for (bit = 0; bit < CFG_ATTR_BIT_MAX; bit++)
    if (bit_test (attrbits, bit))
      {
	attr = attrp + off;
	SET_ISAKMP_ATTR_TYPE (attr, bit);

	if (ie->cfg_type == ISAKMP_CFG_REQUEST)
	  {
	    off += ISAKMP_ATTR_SZ;
	    continue;
	  }

	/* All the other are similar, this is the odd one.  */
	if (bit == ISAKMP_CFG_ATTR_INTERNAL_ADDRESS_EXPIRY)
	  {
	    life = conf_get_num (id_string, "Lifetime", 1200);
	    SET_ISAKMP_ATTR_LENGTH_VALUE (attr, 4);
	    encode_32 (attr + ISAKMP_ATTR_VALUE_OFF, life);
	    off += ISAKMP_ATTR_SZ + 4;
	    continue;
	  }

	switch (bit)
	  {
	  case ISAKMP_CFG_ATTR_INTERNAL_IP4_ADDRESS:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP4_NETMASK:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP4_DNS:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP4_DHCP:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP4_NBNS:
	    length = 4;
	    break;

	  case ISAKMP_CFG_ATTR_INTERNAL_IP6_ADDRESS:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP6_NETMASK:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP6_DNS:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP6_DHCP:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP6_NBNS:
	    length = 16;
	    break;

	  default:
	    length = 0; /* Silence gcc.  */
	  }

	switch (bit)
	  {
	  case ISAKMP_CFG_ATTR_INTERNAL_IP4_ADDRESS:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP6_ADDRESS:
	    field = "Address";
	    break;
	  case ISAKMP_CFG_ATTR_INTERNAL_IP4_NETMASK:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP6_NETMASK:
	    field = "Netmask";
	    break;
	  case ISAKMP_CFG_ATTR_INTERNAL_IP4_DNS:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP6_DNS:
	    field = "Nameserver";
	    break;
	  case ISAKMP_CFG_ATTR_INTERNAL_IP4_DHCP:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP6_DHCP:
	    field = "DHCP-server";
	    break;
	  case ISAKMP_CFG_ATTR_INTERNAL_IP4_NBNS:
	  case ISAKMP_CFG_ATTR_INTERNAL_IP6_NBNS:
	    field = "WINS-server";
	    break;
	  default:
	    field = 0; /* Silence gcc.  */
	  }

	sa = conf_get_address (id_string, field);

	SET_ISAKMP_ATTR_LENGTH_VALUE (attr, length);
	memcpy (attr + ISAKMP_ATTR_VALUE_OFF, sockaddr_addrdata (sa),
		length);

	off += ISAKMP_ATTR_SZ + length;
      }

  if (msg->exchange->phase == 2)
    if (cfg_finalize_hash (msg, hashp, attrp, attrlen))
      goto fail;

  return 0;

 fail:
  if (id_string)
    free (id_string);
  return -1;
}

/*
 * As "the server", this ends SET/ACK.
 * As "the client", this ends REQ/REPLY.
 */
static int
cfg_initiator_recv_ATTR (struct message *msg)
{
  struct payload *attrp
    = TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_ATTRIBUTE]);
  struct ipsec_exch *ie = msg->exchange->data;
  struct sa *isakmp_sa = msg->isakmp_sa;
  struct isakmp_cfg_attr *attr;
  struct sockaddr *sa;
  const char *uk_addr = "<unknown>";
  char *addr;

  if (msg->exchange->phase == 2)
    if (cfg_verify_hash (msg))
      return -1;

  /* Sanity.  */
  if (ie->cfg_id != GET_ISAKMP_ATTRIBUTE_ID (attrp->p))
    {
      log_print ("cfg_initiator_recv_ATTR: cfg packet ID does not match!");
      message_drop (msg, ISAKMP_NOTIFY_PAYLOAD_MALFORMED, 0, 1, 0);
      return -1;
    }

  switch (attrp->p[ISAKMP_ATTRIBUTE_TYPE_OFF])
    {
    case ISAKMP_CFG_ACK:
      if (ie->cfg_type != ISAKMP_CFG_SET)
	{
	  log_print ("cfg_initiator_recv_ATTR: bad packet type ACK");
	  message_drop (msg, ISAKMP_NOTIFY_PAYLOAD_MALFORMED, 0, 1, 0);
	  return -1;
	}
      break;
    case ISAKMP_CFG_REPLY:
      if (ie->cfg_type != ISAKMP_CFG_REQUEST)
	{
	  log_print ("cfg_initiator_recv_ATTR: bad packet type REPLY");
	  message_drop (msg, ISAKMP_NOTIFY_PAYLOAD_MALFORMED, 0, 1, 0);
	  return -1;
	}
      break;

    default:
      log_print ("cfg_initiator_recv_ATTR: "
		 "unexpected configuration message type %d",
		 attrp->p[ISAKMP_ATTRIBUTE_TYPE_OFF]);
      message_drop (msg, ISAKMP_NOTIFY_PAYLOAD_MALFORMED, 0, 1, 0);
      return -1;
    }

  attribute_map (attrp->p + ISAKMP_ATTRIBUTE_ATTRS_OFF,
		 GET_ISAKMP_GEN_LENGTH (attrp->p)
		 - ISAKMP_TRANSFORM_SA_ATTRS_OFF, cfg_decode_attribute, ie);

  switch (ie->cfg_type)
    {
    case ISAKMP_CFG_ACK:
      {
	/* SET/ACK -- Server side (ACK from client) */
	msg->transport->vtbl->get_src (isakmp_sa->transport, &sa);
	if (sockaddr2text (sa, &addr, 0) < 0)
	  addr = (char *)uk_addr;

	for (attr = LIST_FIRST (&ie->attrs); attr;
	     attr = LIST_NEXT (attr, link))
	  LOG_DBG ((LOG_NEGOTIATION, 50, "cfg_initiator_recv_ATTR: "
		    "client %s ACKs attribute %s", addr,
		    constant_name (isakmp_cfg_attr_cst, attr->type)));

	if (addr != uk_addr)
	  free (addr);
      }
      break;

    case ISAKMP_CFG_REPLY:
      {
	/* REQ/REPLY: effect attributes we've gotten responses on.  */
	msg->transport->vtbl->get_src (isakmp_sa->transport, &sa);
	if (sockaddr2text (sa, &addr, 0) < 0)
	  addr = (char *)uk_addr;

	for (attr = LIST_FIRST (&ie->attrs); attr;
	     attr = LIST_NEXT (attr, link))
	  LOG_DBG ((LOG_NEGOTIATION, 50, "cfg_initiator_recv_ATTR: "
		    "server %s replied with attribute %s", addr,
		    constant_name (isakmp_cfg_attr_cst, attr->type)));

	if (addr != uk_addr)
	  free (addr);
      }
      break;

    default:
      break;
    }

  attrp->flags |= PL_MARK;
  return 0;
}

/*
 * As "the server", this starts REQ/REPLY (initiated by the client).
 * As "the client", this starts SET/ACK (initiated by the server).
 */
static int
cfg_responder_recv_ATTR (struct message *msg)
{
  struct payload *attrp
    = TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_ATTRIBUTE]);
  struct ipsec_exch *ie = msg->exchange->data;
  struct sa *isakmp_sa = msg->isakmp_sa;
  struct isakmp_cfg_attr *attr;
  struct sockaddr *sa;
  char *addr;

  if (msg->exchange->phase == 2)
    if (cfg_verify_hash (msg))
      return -1;

  ie->cfg_id = GET_ISAKMP_ATTRIBUTE_ID (attrp->p);
  ie->cfg_type = attrp->p[ISAKMP_ATTRIBUTE_TYPE_OFF];

  switch (ie->cfg_type)
    {
    case ISAKMP_CFG_REQUEST:
    case ISAKMP_CFG_SET:
      break;

    default:
      message_drop (msg, ISAKMP_NOTIFY_PAYLOAD_MALFORMED, 0, 1, 0);
      log_print ("cfg_responder_recv_ATTR: "
		 "unexpected configuration message type %d", ie->cfg_type);
      return -1;
    }

  attribute_map (attrp->p + ISAKMP_ATTRIBUTE_ATTRS_OFF,
		 GET_ISAKMP_GEN_LENGTH (attrp->p)
		 - ISAKMP_TRANSFORM_SA_ATTRS_OFF, cfg_decode_attribute, ie);

  switch (ie->cfg_type)
    {
    case ISAKMP_CFG_REQUEST:
      /* We're done.  */
      break;

    case ISAKMP_CFG_SET:
      {
	/* SET/ACK -- Client side (SET from server) */
	const char *uk_addr = "<unknown>";

	msg->transport->vtbl->get_dst (isakmp_sa->transport, &sa);
	if (sockaddr2text (sa, &addr, 0) < 0)
	  addr = (char *)uk_addr;

	for (attr = LIST_FIRST (&ie->attrs); attr;
	     attr = LIST_NEXT (attr, link))
	  LOG_DBG ((LOG_NEGOTIATION, 50, "cfg_responder_recv_ATTR: "
		    "server %s asks us to SET attribute %s", addr,
		    constant_name (isakmp_cfg_attr_cst, attr->type)));

	/*
	 * XXX Here's the place to add code to walk through each attribute
	 * XXX and send them along to dhclient or whatever. Each attribute
	 * XXX that we act upon (such as setting a netmask), should be
	 * XXX marked like this for us to send the proper ACK response:
	 * XXX   attr->attr_used++;
	 */

	if (addr != uk_addr)
	  free (addr);
      }
      break;

    default:
      break;
    }

  attrp->flags |= PL_MARK;
  return 0;
}

/*
 * As "the server", this ends REQ/REPLY mode.
 * As "the client", this ends SET/ACK mode.
 */
static int
cfg_responder_send_ATTR (struct message *msg)
{
  struct ipsec_exch *ie = msg->exchange->data;
  struct sa *isakmp_sa = msg->isakmp_sa;
  u_int8_t *hashp = 0, *attrp;
  u_int16_t attrlen;
  char *id_string;

  if (msg->exchange->phase == 2)
    {
      hashp = cfg_add_hash (msg);
      if (!hashp)
	return -1;
    }

  /* We are responder, check isakmp_sa for other side.  */
  if (isakmp_sa->initiator ^ (ie->cfg_type == ISAKMP_CFG_REQUEST))
    id_string = ipsec_id_string (isakmp_sa->id_i, isakmp_sa->id_i_len);
  else
    id_string = ipsec_id_string (isakmp_sa->id_r, isakmp_sa->id_r_len);
  if (!id_string)
    {
      log_print ("cfg_responder_send_ATTR: cannot parse client's ID");
      return -1;
    }

  if (cfg_encode_attributes (&ie->attrs, (ie->cfg_type == ISAKMP_CFG_SET ?
					  ISAKMP_CFG_ACK : ISAKMP_CFG_REPLY),
			     ie->cfg_id, id_string, &attrp, &attrlen))
    {
      free (id_string);
      return -1;
    }
  free (id_string);

  if (message_add_payload (msg, ISAKMP_PAYLOAD_ATTRIBUTE, attrp, attrlen, 1))
    {
      free (attrp);
      return -1;
    }

  if (msg->exchange->phase == 2)
    if (cfg_finalize_hash (msg, hashp, attrp, attrlen))
      return -1;

  return 0;
}

u_int8_t *
cfg_add_hash (struct message *msg)
{
  struct ipsec_sa *isa = msg->isakmp_sa->data;
  struct hash *hash = hash_get (isa->hash);
  u_int8_t *hashp;

  hashp = malloc (ISAKMP_HASH_SZ + hash->hashsize);
  if (!hashp)
    {
      log_error ("cfg_add_hash: malloc (%lu) failed",
		 ISAKMP_HASH_SZ + (unsigned long)hash->hashsize);
      return 0;
    }
  if (message_add_payload (msg, ISAKMP_PAYLOAD_HASH, hashp,
			   ISAKMP_HASH_SZ + hash->hashsize, 1))
    {
      free (hashp);
      return 0;
    }
  return hashp;
}

int
cfg_finalize_hash (struct message *msg, u_int8_t *hashp, u_int8_t *data,
		 u_int16_t length)
{
  struct ipsec_sa *isa = msg->isakmp_sa->data;
  struct prf *prf;

  prf = prf_alloc (isa->prf_type, isa->hash, isa->skeyid_a, isa->skeyid_len);
  if (!prf)
    return -1;

  prf->Init (prf->prfctx);
  prf->Update (prf->prfctx, msg->exchange->message_id,
	       ISAKMP_HDR_MESSAGE_ID_LEN);
  prf->Update (prf->prfctx, data, length);
  prf->Final (hashp + ISAKMP_GEN_SZ, prf->prfctx);
  prf_free (prf);
  return 0;
}

int
cfg_verify_hash (struct message *msg)
{
  struct payload *hashp = TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_HASH]);
  struct ipsec_sa *isa = msg->isakmp_sa->data;
  struct prf *prf;
  u_int8_t *hash, *comp_hash;
  size_t hash_len;

  if (!hashp)
    {
      log_print ("cfg_verify_hash: phase 2 message missing HASH");
      message_drop (msg, ISAKMP_NOTIFY_INVALID_HASH_INFORMATION, 0, 1, 0);
      return -1;
    }

  hash = hashp->p;
  hash_len = GET_ISAKMP_GEN_LENGTH (hash);
  comp_hash = malloc (hash_len - ISAKMP_GEN_SZ);
  if (!comp_hash)
    {
      log_error ("cfg_verify_hash: malloc (%lu) failed",
		 (unsigned long)hash_len - ISAKMP_GEN_SZ);
      return -1;
    }

  /* Verify hash.  */
  prf = prf_alloc (isa->prf_type, isa->hash, isa->skeyid_a,
		   isa->skeyid_len);
  if (!prf)
    {
      free (comp_hash);
      return -1;
    }

  prf->Init (prf->prfctx);
  prf->Update (prf->prfctx, msg->exchange->message_id,
	       ISAKMP_HDR_MESSAGE_ID_LEN);
  prf->Update (prf->prfctx, hash + hash_len,
	       msg->iov[0].iov_len - ISAKMP_HDR_SZ - hash_len);
  prf->Final (comp_hash, prf->prfctx);
  prf_free (prf);

  if (memcmp (hash + ISAKMP_GEN_SZ, comp_hash, hash_len - ISAKMP_GEN_SZ) != 0)
    {
      message_drop (msg, ISAKMP_NOTIFY_INVALID_HASH_INFORMATION, 0, 1, 0);
      free (comp_hash);
      return -1;
    }
  free (comp_hash);

  /* Mark the HASH as handled.  */
  hashp->flags |= PL_MARK;

  return 0;
}

/*
 * Decode the attribute of type TYPE with a LEN length value pointed to by
 * VALUE.  VIE is a pointer to the IPsec exchange context holding the
 * attributes indexed by type for easy retrieval.
 */
static int
cfg_decode_attribute (u_int16_t type, u_int8_t *value, u_int16_t len,
		      void *vie)
{
  struct ipsec_exch *ie = vie;
  struct isakmp_cfg_attr *attr;

  if (type >= ISAKMP_CFG_ATTR_PRIVATE_MIN
      && type <= ISAKMP_CFG_ATTR_PRIVATE_MAX)
    return 0;
  if (type == 0 || type >= ISAKMP_CFG_ATTR_FUTURE_MIN)
    {
      LOG_DBG ((LOG_NEGOTIATION, 30,
		"cfg_decode_attribute: invalid attr type %u", type));
      return -1;
    }

  attr = calloc (1, sizeof *attr);
  if (!attr)
    {
      log_error ("cfg_decode_attribute: calloc (1, %lu) failed",
		 (unsigned long)sizeof *attr);
      return -1;
    }
  attr->type = type;
  attr->length = len;
  if (len)
    {
      attr->value = malloc (len);
      if (!attr->value)
	{
	  log_error ("cfg_decode_attribute: malloc (%d) failed", len);
	  free (attr);
	  /* Should we also deallocate all other values?  */
	  return -1;
	}
      memcpy (attr->value, value, len);
    }
  LIST_INSERT_HEAD (&ie->attrs, attr, link);
  return 0;
}

/*
 * Encode list of attributes from ie->attrs into a attribute payload.
 */
static int
cfg_encode_attributes (struct isakmp_cfg_attr_head *attrs, u_int32_t type,
		       u_int32_t cfg_id, char *id_string, u_int8_t **attrp,
		       u_int16_t *len)
{
  struct isakmp_cfg_attr *attr;
  struct sockaddr *sa;
  sa_family_t family;
  u_int32_t value;
  u_int16_t off;
  char *field;

  /* Compute length */
  *len = ISAKMP_ATTRIBUTE_SZ;
  for (attr = LIST_FIRST (attrs); attr; attr = LIST_NEXT (attr, link))
    {
      /* With ACK we only include the attrs we've actually used.  */
      if (type == ISAKMP_CFG_ACK && attr->attr_used == 0)
	continue;

      switch (attr->type)
	{
	case ISAKMP_CFG_ATTR_INTERNAL_IP4_ADDRESS:
	case ISAKMP_CFG_ATTR_INTERNAL_IP4_NETMASK:
	case ISAKMP_CFG_ATTR_INTERNAL_IP4_DHCP:
	case ISAKMP_CFG_ATTR_INTERNAL_IP4_DNS:
	case ISAKMP_CFG_ATTR_INTERNAL_IP4_NBNS:
	case ISAKMP_CFG_ATTR_INTERNAL_ADDRESS_EXPIRY:
	  attr->length = 4;
	  break;

	case ISAKMP_CFG_ATTR_INTERNAL_IP4_SUBNET:
	  attr->length = 8;
	  break;

	case ISAKMP_CFG_ATTR_APPLICATION_VERSION:
	  /* XXX So far no version identifier of isakmpd here.  */
	  attr->length = 0;
	  break;

	case ISAKMP_CFG_ATTR_SUPPORTED_ATTRIBUTES:
	  attr->length = 2 * 15;
	  break;

	case ISAKMP_CFG_ATTR_INTERNAL_IP6_ADDRESS:
	case ISAKMP_CFG_ATTR_INTERNAL_IP6_NETMASK:
	case ISAKMP_CFG_ATTR_INTERNAL_IP6_DHCP:
	case ISAKMP_CFG_ATTR_INTERNAL_IP6_DNS:
	case ISAKMP_CFG_ATTR_INTERNAL_IP6_NBNS:
	  attr->length = 16;
	  break;

	case ISAKMP_CFG_ATTR_INTERNAL_IP6_SUBNET:
	  attr->length = 17;
	  break;

	default:
	  attr->ignore++;
	  /* XXX Log!  */
	}
      *len += ISAKMP_ATTR_SZ + attr->length;
    }

  /* Allocate enough space for the payload */
  *attrp = calloc (1, *len);
  if (!*attrp)
    {
      log_error ("cfg_encode_attributes: calloc (1, %lu) failed",
		 (unsigned long)*len);
      return -1;
    }

  SET_ISAKMP_ATTRIBUTE_TYPE (*attrp, type);
  SET_ISAKMP_ATTRIBUTE_ID (*attrp, cfg_id);

  off = ISAKMP_ATTRIBUTE_SZ;
  for (attr = LIST_FIRST (attrs); attr; attr = LIST_NEXT (attr, link))
    {
      /* With ACK we only include the attrs we've actually used.  */
      if (type == ISAKMP_CFG_ACK && attr->attr_used == 0)
	continue;

      switch (attr->type)
        {
        case ISAKMP_CFG_ATTR_INTERNAL_IP4_ADDRESS:
        case ISAKMP_CFG_ATTR_INTERNAL_IP4_NETMASK:
        case ISAKMP_CFG_ATTR_INTERNAL_IP4_SUBNET:
        case ISAKMP_CFG_ATTR_INTERNAL_IP4_DHCP:
        case ISAKMP_CFG_ATTR_INTERNAL_IP4_DNS:
        case ISAKMP_CFG_ATTR_INTERNAL_IP4_NBNS:
          family = AF_INET;
          break;

        case ISAKMP_CFG_ATTR_INTERNAL_IP6_ADDRESS:
        case ISAKMP_CFG_ATTR_INTERNAL_IP6_NETMASK:
        case ISAKMP_CFG_ATTR_INTERNAL_IP6_SUBNET:
        case ISAKMP_CFG_ATTR_INTERNAL_IP6_DHCP:
        case ISAKMP_CFG_ATTR_INTERNAL_IP6_DNS:
        case ISAKMP_CFG_ATTR_INTERNAL_IP6_NBNS:
          family = AF_INET6;
          break;

        default:
          family = 0;
          break;
        }

      switch (attr->type)
        {
        case ISAKMP_CFG_ATTR_INTERNAL_IP4_ADDRESS:
        case ISAKMP_CFG_ATTR_INTERNAL_IP6_ADDRESS:
          field = "Address";
          break;

        case ISAKMP_CFG_ATTR_INTERNAL_IP4_SUBNET:
        case ISAKMP_CFG_ATTR_INTERNAL_IP6_SUBNET:
          field = "Network"; /* XXX or just "Address" */
          break;

        case ISAKMP_CFG_ATTR_INTERNAL_IP4_NETMASK:
        case ISAKMP_CFG_ATTR_INTERNAL_IP6_NETMASK:
          field = "Netmask";
          break;

        case ISAKMP_CFG_ATTR_INTERNAL_IP4_DHCP:
        case ISAKMP_CFG_ATTR_INTERNAL_IP6_DHCP:
          field = "DHCP-server";
          break;

        case ISAKMP_CFG_ATTR_INTERNAL_IP4_DNS:
        case ISAKMP_CFG_ATTR_INTERNAL_IP6_DNS:
          field = "Nameserver";
          break;

        case ISAKMP_CFG_ATTR_INTERNAL_IP4_NBNS:
        case ISAKMP_CFG_ATTR_INTERNAL_IP6_NBNS:
          field = "WINS-server";
          break;

        default:
          field = 0;
        }

      switch (attr->type)
	{
	case ISAKMP_CFG_ATTR_INTERNAL_IP4_ADDRESS:
	case ISAKMP_CFG_ATTR_INTERNAL_IP6_ADDRESS:
	case ISAKMP_CFG_ATTR_INTERNAL_IP4_NETMASK:
	case ISAKMP_CFG_ATTR_INTERNAL_IP6_NETMASK:
	case ISAKMP_CFG_ATTR_INTERNAL_IP4_DHCP:
	case ISAKMP_CFG_ATTR_INTERNAL_IP6_DHCP:
	case ISAKMP_CFG_ATTR_INTERNAL_IP4_DNS:
	case ISAKMP_CFG_ATTR_INTERNAL_IP6_DNS:
	case ISAKMP_CFG_ATTR_INTERNAL_IP4_NBNS:
	case ISAKMP_CFG_ATTR_INTERNAL_IP6_NBNS:
	  sa = conf_get_address (id_string, field);
	  if (!sa)
	    {
	      LOG_DBG ((LOG_NEGOTIATION, 10, "cfg_responder_send_ATTR: "
			"attribute not found: %s", field));
	      attr->length = 0;
	      break;
	    }

	  if (sa->sa_family != family)
	    {
	      log_print ("cfg_responder_send_ATTR: attribute %s - expected %s "
			 "got %s data", field,
			 (family == AF_INET ? "IPv4" : "IPv6"),
			 (sa->sa_family == AF_INET ? "IPv4" : "IPv6"));
	      free (sa);
	      attr->length = 0;
	      break;
	    }

	  /* Temporary limit length for the _SUBNET types. */
	  if (attr->type == ISAKMP_CFG_ATTR_INTERNAL_IP4_SUBNET)
	    attr->length = 4;
	  else if (attr->type == ISAKMP_CFG_ATTR_INTERNAL_IP6_SUBNET)
	    attr->length = 16;

	  memcpy (*attrp + off + ISAKMP_ATTR_VALUE_OFF, sockaddr_addrdata (sa),
		  attr->length);
	  free (sa);

	  /* _SUBNET types need some extra work. */
	  if (attr->type == ISAKMP_CFG_ATTR_INTERNAL_IP4_SUBNET)
	    {
	      sa = conf_get_address (id_string, "Netmask");
	      if (!sa)
		{
		  LOG_DBG ((LOG_NEGOTIATION, 10, "cfg_responder_send_ATTR: "
			    "attribute not found: Netmask"));
		  attr->length = 0;
		  break;
		}
	      if (sa->sa_family != AF_INET)
		{
		  log_print ("cfg_responder_send_ATTR: attribute Netmask - "
			     "expected IPv4 got IPv6 data");
		  free (sa);
		  attr->length = 0;
		  break;
		}
	      memcpy (*attrp + off + ISAKMP_ATTR_VALUE_OFF + attr->length,
		      sockaddr_addrdata (sa), attr->length);
	      attr->length = 8;
	      free (sa);
	    }
	  else if (attr->type == ISAKMP_CFG_ATTR_INTERNAL_IP6_SUBNET)
	    {
	      int prefix = conf_get_num (id_string, "Prefix", -1);

	      if (prefix == -1)
		{
		  log_print ("cfg_responder_send_ATTR: "
			     "attribute not found: Prefix");
		  attr->length = 0;
		  break;
		}
	      else if (prefix < -1 || prefix > 128)
		{
		  log_print ("cfg_responder_send_ATTR: attribute Prefix - "
			     "invalid value %d", prefix);
		  attr->length = 0;
		  break;
		}

	      *(*attrp + off + ISAKMP_ATTR_VALUE_OFF + 16) = (u_int8_t)prefix;
	      attr->length = 17;
	    }
	  break;

	case ISAKMP_CFG_ATTR_INTERNAL_ADDRESS_EXPIRY:
	  value = conf_get_num (id_string, "Lifetime", 1200);
	  encode_32 (*attrp + off + ISAKMP_ATTR_VALUE_OFF, value);
	  break;

	case ISAKMP_CFG_ATTR_APPLICATION_VERSION:
	  /* XXX So far no version identifier of isakmpd here.  */
	  break;

	case ISAKMP_CFG_ATTR_SUPPORTED_ATTRIBUTES:
	  break;

	default:
	  break;
	}

      SET_ISAKMP_ATTR_TYPE (*attrp + off, attr->type);
      SET_ISAKMP_ATTR_LENGTH_VALUE (*attrp + off, attr->length);
      off += ISAKMP_ATTR_VALUE_OFF + attr->length;
    }

  return 0;
}