/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; version 2 dated June, 1991, or

   (at your option) version 3 dated 29 June, 2007.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "dnsmasq.h"

#ifdef HAVE_DHCP6

#include <netinet/icmp6.h>

static int ping_id = 0;

void slaac_add_addrs(struct dhcp_lease *lease, time_t now, int force)

{

  struct slaac_address *slaac, *old, **up;

  struct dhcp_context *context;

  int dns_dirty = 0;

  if (!(lease->flags & LEASE_HAVE_HWADDR) || 

      (lease->flags & (LEASE_TA | LEASE_NA)) ||

      lease->last_interface == 0 ||

      !lease->hostname)

    return ;

  old = lease->slaac_address;

  lease->slaac_address = NULL;

  for (context = daemon->dhcp6; context; context = context->next) 

    if ((context->flags & CONTEXT_RA_NAME) && 

  !(context->flags & CONTEXT_OLD) &&

  lease->last_interface == context->if_index)

      {

  struct in6_addr addr = context->start6;

  if (lease->hwaddr_len == 6 &&

      (lease->hwaddr_type == ARPHRD_ETHER || lease->hwaddr_type == ARPHRD_IEEE802))

    {

      /* convert MAC address to EUI-64 */

      memcpy(&addr.s6_addr[8], lease->hwaddr, 3);

      memcpy(&addr.s6_addr[13], &lease->hwaddr[3], 3);

      addr.s6_addr[11] = 0xff;

      addr.s6_addr[12] = 0xfe;

    }

#if defined(ARPHRD_EUI64)

  else if (lease->hwaddr_len == 8 &&

     lease->hwaddr_type == ARPHRD_EUI64)

    memcpy(&addr.s6_addr[8], lease->hwaddr, 8);

#endif

#if defined(ARPHRD_IEEE1394) && defined(ARPHRD_EUI64)

  else if (lease->clid_len == 9 && 

     lease->clid[0] ==  ARPHRD_EUI64 &&

     lease->hwaddr_type == ARPHRD_IEEE1394)

    /* FireWire has EUI-64 identifier as clid */

    memcpy(&addr.s6_addr[8], &lease->clid[1], 8);

#endif

  else

    continue;

  addr.s6_addr[8] ^= 0x02;

  /* check if we already have this one */

  for (up = &old, slaac = old; slaac; slaac = slaac->next)

    {

      if (IN6_ARE_ADDR_EQUAL(&addr, &slaac->addr))

        {

    *up = slaac->next;

    /* recheck when DHCPv4 goes through init-reboot */

    if (force)

      {

        slaac->ping_time = now;

        slaac->backoff = 1;

        dns_dirty = 1;

      }

    break;

        }

      up = &slaac->next;

    }

  /* No, make new one */

  if (!slaac && (slaac = whine_malloc(sizeof(struct slaac_address))))

    {

      slaac->ping_time = now;

      slaac->backoff = 1;

      slaac->addr = addr;

      /* Do RA's to prod it */

      ra_start_unsolicited(now, context);

    }

  if (slaac)

    {

      slaac->next = lease->slaac_address;

      lease->slaac_address = slaac;

    }

      }

  if (old || dns_dirty)

    lease_update_dns(1);

  /* Free any no reused */

  for (; old; old = slaac)

    {

      slaac = old->next;

      free(old);

    }

}

time_t periodic_slaac(time_t now, struct dhcp_lease *leases)

{

  struct dhcp_context *context;

  struct dhcp_lease *lease;

  struct slaac_address *slaac;

  time_t next_event = 0;

  for (context = daemon->dhcp6; context; context = context->next)

    if ((context->flags & CONTEXT_RA_NAME) && !(context->flags & CONTEXT_OLD))

      break;

  /* nothing configured */

  if (!context)

    return 0;

  while (ping_id == 0)

    ping_id = rand16();

  for (lease = leases; lease; lease = lease->next)

    for (slaac = lease->slaac_address; slaac; slaac = slaac->next)

      {

  /* confirmed or given up? */

  if (slaac->backoff == 0 || slaac->ping_time == 0)

    continue;

  if (difftime(slaac->ping_time, now) <= 0.0)

    {

      struct ping_packet *ping;

      struct sockaddr_in6 addr;

      reset_counter();

      if (!(ping = expand(sizeof(struct ping_packet))))

        continue;

      ping->type = ICMP6_ECHO_REQUEST;

      ping->code = 0;

      ping->identifier = ping_id;

      ping->sequence_no = slaac->backoff;

      memset(&addr, 0, sizeof(addr));

#ifdef HAVE_SOCKADDR_SA_LEN

      addr.sin6_len = sizeof(struct sockaddr_in6);

#endif

      addr.sin6_family = AF_INET6;

      addr.sin6_port = htons(IPPROTO_ICMPV6);

      addr.sin6_addr = slaac->addr;

      if (sendto(daemon->icmp6fd, daemon->outpacket.iov_base, save_counter(-1), 0,

           (struct sockaddr *)&addr,  sizeof(addr)) == -1 &&

    errno == EHOSTUNREACH &&

    slaac->backoff == 12)

        slaac->ping_time = 0; /* Give up */ 

      else

        {

    slaac->ping_time += (1 << (slaac->backoff - 1)) + (rand16()/21785); /* 0 - 3 */

    if (slaac->backoff > 4)

      slaac->ping_time += rand16()/4000; /* 0 - 15 */

    if (slaac->backoff < 12)

      slaac->backoff++;

        }

    }

  if (slaac->ping_time != 0 &&

      (next_event == 0 || difftime(next_event, slaac->ping_time) >= 0.0))

    next_event = slaac->ping_time;

      }

  return next_event;

}

void slaac_ping_reply(struct in6_addr *sender, unsigned char *packet, char *interface, struct dhcp_lease *leases)

{

  struct dhcp_lease *lease;

  struct slaac_address *slaac;

  struct ping_packet *ping = (struct ping_packet *)packet;

  int gotone = 0;

  if (ping->identifier == ping_id)

    for (lease = leases; lease; lease = lease->next)

      for (slaac = lease->slaac_address; slaac; slaac = slaac->next)

  if (slaac->backoff != 0 && IN6_ARE_ADDR_EQUAL(sender, &slaac->addr))

    {

      slaac->backoff = 0;

      gotone = 1;

      inet_ntop(AF_INET6, sender, daemon->addrbuff, ADDRSTRLEN);

      if (!option_bool(OPT_QUIET_DHCP6))

        my_syslog(MS_DHCP | LOG_INFO, "SLAAC-CONFIRM(%s) %s %s", interface, daemon->addrbuff, lease->hostname); 

    }

  lease_update_dns(gotone);

}

#endif