src/radv.c - thekelleys/dnsmasq - Gitiles

 /* dnsmasq is Copyright (c) 2000-2012 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/>.
 */


 /* NB. This code may be called during a DHCPv4 or transaction which is in ping-wait
    It therefore cannot use any DHCP buffer resources except outpacket, which is
    not used by DHCPv4 code. This code may also be called when DHCP 4 or 6 isn't
    active, so we ensure that outpacket is allocated here too */

 #include "dnsmasq.h"

 #ifdef HAVE_DHCP6

 #include <netinet/icmp6.h>

 struct ra_param {
   time_t now;
   int ind, managed, other, found_context, first;
   char *if_name;
   struct dhcp_netid *tags;
   struct in6_addr link_local, link_global;
   unsigned int pref_time;
 };

 struct search_param {
   time_t now; int iface;
 };

 static void send_ra(time_t now, int iface, char *iface_name, struct in6_addr *dest);
 static int add_prefixes(struct in6_addr *local,  int prefix,
 			int scope, int if_index, int flags,
 			unsigned int preferred, unsigned int valid, void *vparam);
 static int iface_search(struct in6_addr *local,  int prefix,
 			int scope, int if_index, int flags,
 			int prefered, int valid, void *vparam);
 static int add_lla(int index, unsigned int type, char *mac, size_t maclen, void *parm);

 static int hop_limit;

 void ra_init(time_t now)
 {
   struct icmp6_filter filter;
   int fd;
 #if defined(IPV6_TCLASS) && defined(IPTOS_CLASS_CS6)
   int class = IPTOS_CLASS_CS6;
 #endif
   int val = 255; /* radvd uses this value */
   socklen_t len = sizeof(int);
   struct dhcp_context *context;

   /* ensure this is around even if we're not doing DHCPv6 */
   expand_buf(&daemon->outpacket, sizeof(struct dhcp_packet));

   /* See if we're guessing SLAAC addresses, if so we need to recieve ping replies */
   for (context = daemon->dhcp6; context; context = context->next)
     if ((context->flags & CONTEXT_RA_NAME))
       break;

   ICMP6_FILTER_SETBLOCKALL(&filter);
   ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filter);
   if (context)
     ICMP6_FILTER_SETPASS(ICMP6_ECHO_REPLY, &filter);

   if ((fd = socket(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) == -1 ||
       getsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &hop_limit, &len) ||
 #if defined(IPV6_TCLASS) && defined(IPTOS_CLASS_CS6)
       setsockopt(fd, IPPROTO_IPV6, IPV6_TCLASS, &class, sizeof(class)) == -1 ||
 #endif
       !fix_fd(fd) ||
       !set_ipv6pktinfo(fd) ||
       setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val)) ||
       setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val)) ||
       setsockopt(fd, IPPROTO_ICMPV6, ICMP6_FILTER, &filter, sizeof(filter)) == -1)
     die (_("cannot create ICMPv6 socket: %s"), NULL, EC_BADNET);

    daemon->icmp6fd = fd;

    ra_start_unsolicted(now, NULL);
 }

 void ra_start_unsolicted(time_t now, struct dhcp_context *context)
 {
    /* init timers so that we do ra's for some/all soon. some ra_times will end up zeroed
      if it's not appropriate to advertise those contexts.
      This gets re-called on a netlink route-change to re-do the advertisement
      and pick up new interfaces */

   if (context)
     context->ra_short_period_start = context->ra_time = now;
   else
     for (context = daemon->dhcp6; context; context = context->next)
       if (!(context->flags & CONTEXT_TEMPLATE))
 	{
 	  context->ra_time = now + (rand16()/13000); /* range 0 - 5 */
 	  /* re-do frequently for a minute or so, in case the first gets lost. */
 	  context->ra_short_period_start = now;
 	}
 }

 void icmp6_packet(time_t now)
 {
   char interface[IF_NAMESIZE+1];
   ssize_t sz;
   int if_index = 0;
   struct cmsghdr *cmptr;
   struct msghdr msg;
   union {
     struct cmsghdr align; /* this ensures alignment */
     char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
   } control_u;
   struct sockaddr_in6 from;
   unsigned char *packet;
   struct iname *tmp;

   /* Note: use outpacket for input buffer */
   msg.msg_control = control_u.control6;
   msg.msg_controllen = sizeof(control_u);
   msg.msg_flags = 0;
   msg.msg_name = &from;
   msg.msg_namelen = sizeof(from);
   msg.msg_iov = &daemon->outpacket;
   msg.msg_iovlen = 1;

   if ((sz = recv_dhcp_packet(daemon->icmp6fd, &msg)) == -1 || sz < 8)
     return;

   packet = (unsigned char *)daemon->outpacket.iov_base;

   for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
     if (cmptr->cmsg_level == IPPROTO_IPV6 && cmptr->cmsg_type == daemon->v6pktinfo)
       {
 	union {
 	  unsigned char *c;
 	  struct in6_pktinfo *p;
 	} p;
 	p.c = CMSG_DATA(cmptr);

 	if_index = p.p->ipi6_ifindex;
       }

   if (!indextoname(daemon->icmp6fd, if_index, interface))
     return;

   if (!iface_check(AF_LOCAL, NULL, interface, NULL))
     return;

   for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next)
     if (tmp->name && (strcmp(tmp->name, interface) == 0))
       return;

   if (packet[1] != 0)
     return;

   if (packet[0] == ICMP6_ECHO_REPLY)
     lease_ping_reply(&from.sin6_addr, packet, interface);
   else if (packet[0] == ND_ROUTER_SOLICIT)
     {
       char *mac = "";

       /* look for link-layer address option for logging */
       if (sz >= 16 && packet[8] == ICMP6_OPT_SOURCE_MAC && (packet[9] * 8) + 8 <= sz)
 	{
 	  print_mac(daemon->namebuff, &packet[10], (packet[9] * 8) - 2);
 	  mac = daemon->namebuff;
 	}

       my_syslog(MS_DHCP | LOG_INFO, "RTR-SOLICIT(%s) %s", interface, mac);
       /* source address may not be valid in solicit request. */
       send_ra(now, if_index, interface, !IN6_IS_ADDR_UNSPECIFIED(&from.sin6_addr) ? &from.sin6_addr : NULL);
     }
 }

 static void send_ra(time_t now, int iface, char *iface_name, struct in6_addr *dest)
 {
   struct ra_packet *ra;
   struct ra_param parm;
   struct ifreq ifr;
   struct sockaddr_in6 addr;
   struct dhcp_context *context;
   struct dhcp_netid iface_id;
   struct dhcp_opt *opt_cfg;
   int done_dns = 0;

   save_counter(0);
   ra = expand(sizeof(struct ra_packet));

   ra->type = ND_ROUTER_ADVERT;
   ra->code = 0;
   ra->hop_limit = hop_limit;
   ra->flags = 0x00;
   ra->lifetime = htons(1800); /* AdvDefaultLifetime*/
   ra->reachable_time = 0;
   ra->retrans_time = 0;

   parm.ind = iface;
   parm.managed = 0;
   parm.other = 0;
   parm.found_context = 0;
   parm.if_name = iface_name;
   parm.first = 1;
   parm.now = now;
   parm.pref_time = 0;

   /* set tag with name == interface */
   iface_id.net = iface_name;
   iface_id.next = NULL;
   parm.tags = &iface_id;

   for (context = daemon->dhcp6; context; context = context->next)
     {
       context->flags &= ~CONTEXT_RA_DONE;
       context->netid.next = &context->netid;
     }

   if (!iface_enumerate(AF_INET6, &parm, add_prefixes) ||
       !parm.found_context)
     return;

   strncpy(ifr.ifr_name, iface_name, IF_NAMESIZE);

   if (ioctl(daemon->icmp6fd, SIOCGIFMTU, &ifr) != -1)
     {
       put_opt6_char(ICMP6_OPT_MTU);
       put_opt6_char(1);
       put_opt6_short(0);
       put_opt6_long(ifr.ifr_mtu);
     }

   iface_enumerate(AF_LOCAL, &iface, add_lla);

   /* RDNSS, RFC 6106, use relevant DHCP6 options */
   (void)option_filter(parm.tags, NULL, daemon->dhcp_opts6);

   for (opt_cfg = daemon->dhcp_opts6; opt_cfg; opt_cfg = opt_cfg->next)
     {
       int i;

       /* netids match and not encapsulated? */
       if (!(opt_cfg->flags & DHOPT_TAGOK))
         continue;

       if (opt_cfg->opt == OPTION6_DNS_SERVER)
         {
 	  struct in6_addr *a = (struct in6_addr *)opt_cfg->val;

 	  done_dns = 1;
           if (opt_cfg->len == 0)
             continue;

 	  put_opt6_char(ICMP6_OPT_RDNSS);
 	  put_opt6_char((opt_cfg->len/8) + 1);
 	  put_opt6_short(0);
 	  put_opt6_long(1800); /* lifetime - twice RA retransmit */
 	  /* zero means "self" */
 	  for (i = 0; i < opt_cfg->len; i += IN6ADDRSZ, a++)
 	    if (IN6_IS_ADDR_UNSPECIFIED(a))
 	      put_opt6(&parm.link_global, IN6ADDRSZ);
 	    else
 	      put_opt6(a, IN6ADDRSZ);
 	}

       if (opt_cfg->opt == OPTION6_DOMAIN_SEARCH && opt_cfg->len != 0)
 	{
 	  int len = ((opt_cfg->len+7)/8);

 	  put_opt6_char(ICMP6_OPT_DNSSL);
 	  put_opt6_char(len + 1);
 	  put_opt6_short(0);
 	  put_opt6_long(1800); /* lifetime - twice RA retransmit */
 	  put_opt6(opt_cfg->val, opt_cfg->len);

 	  /* pad */
 	  for (i = opt_cfg->len; i < len * 8; i++)
 	    put_opt6_char(0);
 	}
     }

   if (!done_dns)
     {
       /* default == us. */
       put_opt6_char(ICMP6_OPT_RDNSS);
       put_opt6_char(3);
       put_opt6_short(0);
       put_opt6_long(1800); /* lifetime - twice RA retransmit */
       put_opt6(&parm.link_global, IN6ADDRSZ);
     }

   /* set managed bits unless we're providing only RA on this link */
   if (parm.managed)
     ra->flags |= 0x80; /* M flag, managed, */
    if (parm.other)
     ra->flags |= 0x40; /* O flag, other */

   /* decide where we're sending */
   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);
   if (dest)
     {
       addr.sin6_addr = *dest;
       if (IN6_IS_ADDR_LINKLOCAL(dest) ||
 	  IN6_IS_ADDR_MC_LINKLOCAL(dest))
 	addr.sin6_scope_id = iface;
     }
   else
     inet_pton(AF_INET6, ALL_NODES, &addr.sin6_addr);

   send_from(daemon->icmp6fd, 0, daemon->outpacket.iov_base, save_counter(0),
 	    (union mysockaddr *)&addr, (struct all_addr *)&parm.link_local, iface);

 }

 static int add_prefixes(struct in6_addr *local,  int prefix,
 			int scope, int if_index, int flags,
 			unsigned int preferred, unsigned int valid, void *vparam)
 {
   struct ra_param *param = vparam;

   (void)scope; /* warning */

   if (if_index == param->ind)
     {
       if (IN6_IS_ADDR_LINKLOCAL(local))
 	param->link_local = *local;
       else if (!IN6_IS_ADDR_LOOPBACK(local) &&
 	       !IN6_IS_ADDR_MULTICAST(local))
 	{
 	  int do_prefix = 0;
 	  int do_slaac = 0;
 	  int deprecate  = 0;
 	  int constructed = 0;
 	  unsigned int time = 0xffffffff;
 	  struct dhcp_context *context;

 	  for (context = daemon->dhcp6; context; context = context->next)
 	    if (!(context->flags & CONTEXT_TEMPLATE) &&
 		prefix == context->prefix &&
 		is_same_net6(local, &context->start6, prefix) &&
 		is_same_net6(local, &context->end6, prefix))
 	      {
 		if ((context->flags &
 		     (CONTEXT_RA_ONLY | CONTEXT_RA_NAME | CONTEXT_RA_STATELESS)))
 		  {
 		    do_slaac = 1;
 		    if (context->flags & CONTEXT_DHCP)
 		      {
 			param->other = 1;
 			if (!(context->flags & CONTEXT_RA_STATELESS))
 			  param->managed = 1;
 		      }
 		  }
 		else
 		  {
 		    /* don't do RA for non-ra-only unless --enable-ra is set */
 		    if (!option_bool(OPT_RA))
 		      continue;
 		    param->managed = 1;
 		    param->other = 1;
 		  }

 		/* find floor time, don't reduce below RA interval. */
 		if (time > context->lease_time)
 		  {
 		    time = context->lease_time;
 		    if (time < 600u)
 		      time = 600;
 		  }

 		if (context->flags & CONTEXT_DEPRECATE)
 		  deprecate = 1;

 		if (context->flags & CONTEXT_CONSTRUCTED)
 		  constructed = 1;


 		/* collect dhcp-range tags */
 		if (context->netid.next == &context->netid && context->netid.net)
 		  {
 		    context->netid.next = param->tags;
 		    param->tags = &context->netid;
 		  }

 		/* subsequent prefixes on the same interface
 		   and subsequent instances of this prefix don't need timers.
 		   Be careful not to find the same prefix twice with different
 		   addresses. */
 		if (!(context->flags & CONTEXT_RA_DONE))
 		  {
 		    if (!param->first)
 		      context->ra_time = 0;
 		    context->flags |= CONTEXT_RA_DONE;
 		    do_prefix = 1;
 		  }

 		param->first = 0;
 		param->found_context = 1;
 	      }

 	  /* configured time is ceiling */
 	  if (!constructed || valid > time)
 	    valid = time;

 	  if (flags & IFACE_DEPRECATED)
 	    preferred = 0;

 	  if (deprecate)
 	    time = 0;

 	  /* configured time is ceiling */
 	  if (!constructed || preferred > time)
 	    preferred = time;

 	  if (preferred > param->pref_time)
 	    {
 	      param->pref_time = preferred;
 	      param->link_global = *local;
 	    }

 	  if (do_prefix)
 	    {
 	      struct prefix_opt *opt;

 	      if ((opt = expand(sizeof(struct prefix_opt))))
 		{
 		  /* zero net part of address */
 		  setaddr6part(local, addr6part(local) & ~((prefix == 64) ? (u64)-1LL : (1LLU << (128 - prefix)) - 1LLU));

 		  opt->type = ICMP6_OPT_PREFIX;
 		  opt->len = 4;
 		  opt->prefix_len = prefix;
 		  /* autonomous only if we're not doing dhcp, always set "on-link" */
 		  opt->flags = do_slaac ? 0xC0 : 0x80;
 		  opt->valid_lifetime = htonl(valid);
 		  opt->preferred_lifetime = htonl(preferred);
 		  opt->reserved = 0;
 		  opt->prefix = *local;

 		  inet_ntop(AF_INET6, local, daemon->addrbuff, ADDRSTRLEN);
 		  my_syslog(MS_DHCP | LOG_INFO, "RTR-ADVERT(%s) %s", param->if_name, daemon->addrbuff);
 		}
 	    }
 	}
     }
   return 1;
 }

 static int add_lla(int index, unsigned int type, char *mac, size_t maclen, void *parm)
 {
   (void)type;

   if (index == *((int *)parm))
     {
       /* size is in units of 8 octets and includes type and length (2 bytes)
 	 add 7 to round up */
       int len = (maclen + 9) >> 3;
       unsigned char *p = expand(len << 3);
       memset(p, 0, len << 3);
       *p++ = ICMP6_OPT_SOURCE_MAC;
       *p++ = len;
       memcpy(p, mac, maclen);

       return 0;
     }

   return 1;
 }

 time_t periodic_ra(time_t now)
 {
   struct search_param param;
   struct dhcp_context *context;
   time_t next_event;
   char interface[IF_NAMESIZE+1];

   param.now = now;
   param.iface = 0;

   while (1)
     {
       /* find overdue events, and time of first future event */
       for (next_event = 0, context = daemon->dhcp6; context; context = context->next)
 	if (context->ra_time != 0)
 	  {
 	    if (difftime(context->ra_time, now) <= 0.0)
 	      break; /* overdue */

 	    if (next_event == 0 || difftime(next_event, context->ra_time) > 0.0)
 	      next_event = context->ra_time;
 	  }

       /* none overdue */
       if (!context)
 	break;

       /* There's a context overdue, but we can't find an interface
 	 associated with it, because it's for a subnet we dont
 	 have an interface on. Probably we're doing DHCP on
 	 a remote subnet via a relay. Zero the timer, since we won't
 	 ever be able to send ra's and satistfy it. */
       if (iface_enumerate(AF_INET6, &param, iface_search))
 	context->ra_time = 0;
       else if (param.iface != 0 &&
 	       indextoname(daemon->icmp6fd, param.iface, interface) &&
 	       iface_check(AF_LOCAL, NULL, interface, NULL))
 	{
 	  struct iname *tmp;
 	  for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next)
 	    if (tmp->name && (strcmp(tmp->name, interface) == 0))
 	      break;
 	  if (!tmp)
 	    send_ra(now, param.iface, interface, NULL);
 	}
     }
   return next_event;
 }

 static int iface_search(struct in6_addr *local,  int prefix,
 			int scope, int if_index, int flags,
 			int preferred, int valid, void *vparam)
 {
   struct search_param *param = vparam;
   struct dhcp_context *context;

   (void)scope;
   (void)preferred;
   (void)valid;

   for (context = daemon->dhcp6; context; context = context->next)
     if (!(context->flags & CONTEXT_TEMPLATE) &&
 	prefix == context->prefix &&
 	is_same_net6(local, &context->start6, prefix) &&
 	is_same_net6(local, &context->end6, prefix) &&
 	context->ra_time != 0 &&
 	difftime(context->ra_time, param->now) <= 0.0)
       {
 	/* found an interface that's overdue for RA determine new
 	   timeout value and arrange for RA to be sent unless interface is
 	   still doing DAD.*/

 	if (!(flags & IFACE_TENTATIVE))
 	  param->iface = if_index;

 	if (difftime(param->now, context->ra_short_period_start) < 60.0)
 	  /* range 5 - 20 */
 	  context->ra_time = param->now + 5 + (rand16()/4400);
 	else
 	  /* range 450 - 600 */
 	  context->ra_time = param->now + 450 + (rand16()/440);

 	/* zero timers for other contexts on the same subnet, so they don't timeout
 	   independently */
 	for (context = context->next; context; context = context->next)
 	  if (prefix == context->prefix &&
 	      is_same_net6(local, &context->start6, prefix) &&
 	      is_same_net6(local, &context->end6, prefix))
 	    context->ra_time = 0;

 	return 0; /* found, abort */
       }

   return 1; /* keep searching */
 }


 #endif
	/* dnsmasq is Copyright (c) 2000-2012 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/>.
	*/


	/* NB. This code may be called during a DHCPv4 or transaction which is in ping-wait
	It therefore cannot use any DHCP buffer resources except outpacket, which is
	not used by DHCPv4 code. This code may also be called when DHCP 4 or 6 isn't
	active, so we ensure that outpacket is allocated here too */

	#include "dnsmasq.h"

	#ifdef HAVE_DHCP6

	#include <netinet/icmp6.h>

	struct ra_param {
	time_t now;
	int ind, managed, other, found_context, first;
	char *if_name;
	struct dhcp_netid *tags;
	struct in6_addr link_local, link_global;
	unsigned int pref_time;
	};

	struct search_param {
	time_t now; int iface;
	};

	static void send_ra(time_t now, int iface, char iface_name, struct in6_addr dest);
	static int add_prefixes(struct in6_addr *local, int prefix,
	int scope, int if_index, int flags,
	unsigned int preferred, unsigned int valid, void *vparam);
	static int iface_search(struct in6_addr *local, int prefix,
	int scope, int if_index, int flags,
	int prefered, int valid, void *vparam);
	static int add_lla(int index, unsigned int type, char mac, size_t maclen, void parm);

	static int hop_limit;

	void ra_init(time_t now)
	{
	struct icmp6_filter filter;
	int fd;
	#if defined(IPV6_TCLASS) && defined(IPTOS_CLASS_CS6)
	int class = IPTOS_CLASS_CS6;
	#endif
	int val = 255; /* radvd uses this value */
	socklen_t len = sizeof(int);
	struct dhcp_context *context;

	/* ensure this is around even if we're not doing DHCPv6 */
	expand_buf(&daemon->outpacket, sizeof(struct dhcp_packet));

	/* See if we're guessing SLAAC addresses, if so we need to recieve ping replies */
	for (context = daemon->dhcp6; context; context = context->next)
	if ((context->flags & CONTEXT_RA_NAME))
	break;

	ICMP6_FILTER_SETBLOCKALL(&filter);
	ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filter);
	if (context)
	ICMP6_FILTER_SETPASS(ICMP6_ECHO_REPLY, &filter);

	if ((fd = socket(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) == -1 \|\|
	getsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &hop_limit, &len) \|\|
	#if defined(IPV6_TCLASS) && defined(IPTOS_CLASS_CS6)
	setsockopt(fd, IPPROTO_IPV6, IPV6_TCLASS, &class, sizeof(class)) == -1 \|\|
	#endif
	!fix_fd(fd) \|\|
	!set_ipv6pktinfo(fd) \|\|
	setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val)) \|\|
	setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val)) \|\|
	setsockopt(fd, IPPROTO_ICMPV6, ICMP6_FILTER, &filter, sizeof(filter)) == -1)
	die (_("cannot create ICMPv6 socket: %s"), NULL, EC_BADNET);

	daemon->icmp6fd = fd;

	ra_start_unsolicted(now, NULL);
	}

	void ra_start_unsolicted(time_t now, struct dhcp_context *context)
	{
	/* init timers so that we do ra's for some/all soon. some ra_times will end up zeroed
	if it's not appropriate to advertise those contexts.
	This gets re-called on a netlink route-change to re-do the advertisement
	and pick up new interfaces */

	if (context)
	context->ra_short_period_start = context->ra_time = now;
	else
	for (context = daemon->dhcp6; context; context = context->next)
	if (!(context->flags & CONTEXT_TEMPLATE))
	{
	context->ra_time = now + (rand16()/13000); /* range 0 - 5 */
	/* re-do frequently for a minute or so, in case the first gets lost. */
	context->ra_short_period_start = now;
	}
	}

	void icmp6_packet(time_t now)
	{
	char interface[IF_NAMESIZE+1];
	ssize_t sz;
	int if_index = 0;
	struct cmsghdr *cmptr;
	struct msghdr msg;
	union {
	struct cmsghdr align; /* this ensures alignment */
	char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
	} control_u;
	struct sockaddr_in6 from;
	unsigned char *packet;
	struct iname *tmp;

	/* Note: use outpacket for input buffer */
	msg.msg_control = control_u.control6;
	msg.msg_controllen = sizeof(control_u);
	msg.msg_flags = 0;
	msg.msg_name = &from;
	msg.msg_namelen = sizeof(from);
	msg.msg_iov = &daemon->outpacket;
	msg.msg_iovlen = 1;

	if ((sz = recv_dhcp_packet(daemon->icmp6fd, &msg)) == -1 \|\| sz < 8)
	return;

	packet = (unsigned char *)daemon->outpacket.iov_base;

	for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
	if (cmptr->cmsg_level == IPPROTO_IPV6 && cmptr->cmsg_type == daemon->v6pktinfo)
	{
	union {
	unsigned char *c;
	struct in6_pktinfo *p;
	} p;
	p.c = CMSG_DATA(cmptr);

	if_index = p.p->ipi6_ifindex;
	}

	if (!indextoname(daemon->icmp6fd, if_index, interface))
	return;

	if (!iface_check(AF_LOCAL, NULL, interface, NULL))
	return;

	for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next)
	if (tmp->name && (strcmp(tmp->name, interface) == 0))
	return;

	if (packet[1] != 0)
	return;

	if (packet[0] == ICMP6_ECHO_REPLY)
	lease_ping_reply(&from.sin6_addr, packet, interface);
	else if (packet[0] == ND_ROUTER_SOLICIT)
	{
	char *mac = "";

	/* look for link-layer address option for logging */
	if (sz >= 16 && packet[8] == ICMP6_OPT_SOURCE_MAC && (packet[9] * 8) + 8 <= sz)
	{
	print_mac(daemon->namebuff, &packet[10], (packet[9] * 8) - 2);
	mac = daemon->namebuff;
	}

	my_syslog(MS_DHCP \| LOG_INFO, "RTR-SOLICIT(%s) %s", interface, mac);
	/* source address may not be valid in solicit request. */
	send_ra(now, if_index, interface, !IN6_IS_ADDR_UNSPECIFIED(&from.sin6_addr) ? &from.sin6_addr : NULL);
	}
	}

	static void send_ra(time_t now, int iface, char iface_name, struct in6_addr dest)
	{
	struct ra_packet *ra;
	struct ra_param parm;
	struct ifreq ifr;
	struct sockaddr_in6 addr;
	struct dhcp_context *context;
	struct dhcp_netid iface_id;
	struct dhcp_opt *opt_cfg;
	int done_dns = 0;

	save_counter(0);
	ra = expand(sizeof(struct ra_packet));

	ra->type = ND_ROUTER_ADVERT;
	ra->code = 0;
	ra->hop_limit = hop_limit;
	ra->flags = 0x00;
	ra->lifetime = htons(1800); /* AdvDefaultLifetime*/
	ra->reachable_time = 0;
	ra->retrans_time = 0;

	parm.ind = iface;
	parm.managed = 0;
	parm.other = 0;
	parm.found_context = 0;
	parm.if_name = iface_name;
	parm.first = 1;
	parm.now = now;
	parm.pref_time = 0;

	/* set tag with name == interface */
	iface_id.net = iface_name;
	iface_id.next = NULL;
	parm.tags = &iface_id;

	for (context = daemon->dhcp6; context; context = context->next)
	{
	context->flags &= ~CONTEXT_RA_DONE;
	context->netid.next = &context->netid;
	}

	if (!iface_enumerate(AF_INET6, &parm, add_prefixes) \|\|
	!parm.found_context)
	return;

	strncpy(ifr.ifr_name, iface_name, IF_NAMESIZE);

	if (ioctl(daemon->icmp6fd, SIOCGIFMTU, &ifr) != -1)
	{
	put_opt6_char(ICMP6_OPT_MTU);
	put_opt6_char(1);
	put_opt6_short(0);
	put_opt6_long(ifr.ifr_mtu);
	}

	iface_enumerate(AF_LOCAL, &iface, add_lla);

	/* RDNSS, RFC 6106, use relevant DHCP6 options */
	(void)option_filter(parm.tags, NULL, daemon->dhcp_opts6);

	for (opt_cfg = daemon->dhcp_opts6; opt_cfg; opt_cfg = opt_cfg->next)
	{
	int i;

	/* netids match and not encapsulated? */
	if (!(opt_cfg->flags & DHOPT_TAGOK))
	continue;

	if (opt_cfg->opt == OPTION6_DNS_SERVER)
	{
	struct in6_addr a = (struct in6_addr )opt_cfg->val;

	done_dns = 1;
	if (opt_cfg->len == 0)
	continue;

	put_opt6_char(ICMP6_OPT_RDNSS);
	put_opt6_char((opt_cfg->len/8) + 1);
	put_opt6_short(0);
	put_opt6_long(1800); /* lifetime - twice RA retransmit */
	/* zero means "self" */
	for (i = 0; i < opt_cfg->len; i += IN6ADDRSZ, a++)
	if (IN6_IS_ADDR_UNSPECIFIED(a))
	put_opt6(&parm.link_global, IN6ADDRSZ);
	else
	put_opt6(a, IN6ADDRSZ);
	}

	if (opt_cfg->opt == OPTION6_DOMAIN_SEARCH && opt_cfg->len != 0)
	{
	int len = ((opt_cfg->len+7)/8);

	put_opt6_char(ICMP6_OPT_DNSSL);
	put_opt6_char(len + 1);
	put_opt6_short(0);
	put_opt6_long(1800); /* lifetime - twice RA retransmit */
	put_opt6(opt_cfg->val, opt_cfg->len);

	/* pad */
	for (i = opt_cfg->len; i < len * 8; i++)
	put_opt6_char(0);
	}
	}

	if (!done_dns)
	{
	/* default == us. */
	put_opt6_char(ICMP6_OPT_RDNSS);
	put_opt6_char(3);
	put_opt6_short(0);
	put_opt6_long(1800); /* lifetime - twice RA retransmit */
	put_opt6(&parm.link_global, IN6ADDRSZ);
	}

	/* set managed bits unless we're providing only RA on this link */
	if (parm.managed)
	ra->flags \|= 0x80; /* M flag, managed, */
	if (parm.other)
	ra->flags \|= 0x40; /* O flag, other */

	/* decide where we're sending */
	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);
	if (dest)
	{
	addr.sin6_addr = *dest;
	if (IN6_IS_ADDR_LINKLOCAL(dest) \|\|
	IN6_IS_ADDR_MC_LINKLOCAL(dest))
	addr.sin6_scope_id = iface;
	}
	else
	inet_pton(AF_INET6, ALL_NODES, &addr.sin6_addr);

	send_from(daemon->icmp6fd, 0, daemon->outpacket.iov_base, save_counter(0),
	(union mysockaddr )&addr, (struct all_addr )&parm.link_local, iface);

	}

	static int add_prefixes(struct in6_addr *local, int prefix,
	int scope, int if_index, int flags,
	unsigned int preferred, unsigned int valid, void *vparam)
	{
	struct ra_param *param = vparam;

	(void)scope; /* warning */

	if (if_index == param->ind)
	{
	if (IN6_IS_ADDR_LINKLOCAL(local))
	param->link_local = *local;
	else if (!IN6_IS_ADDR_LOOPBACK(local) &&
	!IN6_IS_ADDR_MULTICAST(local))
	{
	int do_prefix = 0;
	int do_slaac = 0;
	int deprecate = 0;
	int constructed = 0;
	unsigned int time = 0xffffffff;
	struct dhcp_context *context;

	for (context = daemon->dhcp6; context; context = context->next)
	if (!(context->flags & CONTEXT_TEMPLATE) &&
	prefix == context->prefix &&
	is_same_net6(local, &context->start6, prefix) &&
	is_same_net6(local, &context->end6, prefix))
	{
	if ((context->flags &
	(CONTEXT_RA_ONLY \| CONTEXT_RA_NAME \| CONTEXT_RA_STATELESS)))
	{
	do_slaac = 1;
	if (context->flags & CONTEXT_DHCP)
	{
	param->other = 1;
	if (!(context->flags & CONTEXT_RA_STATELESS))
	param->managed = 1;
	}
	}
	else
	{
	/* don't do RA for non-ra-only unless --enable-ra is set */
	if (!option_bool(OPT_RA))
	continue;
	param->managed = 1;
	param->other = 1;
	}

	/* find floor time, don't reduce below RA interval. */
	if (time > context->lease_time)
	{
	time = context->lease_time;
	if (time < 600u)
	time = 600;
	}

	if (context->flags & CONTEXT_DEPRECATE)
	deprecate = 1;

	if (context->flags & CONTEXT_CONSTRUCTED)
	constructed = 1;


	/* collect dhcp-range tags */
	if (context->netid.next == &context->netid && context->netid.net)
	{
	context->netid.next = param->tags;
	param->tags = &context->netid;
	}

	/* subsequent prefixes on the same interface
	and subsequent instances of this prefix don't need timers.
	Be careful not to find the same prefix twice with different
	addresses. */
	if (!(context->flags & CONTEXT_RA_DONE))
	{
	if (!param->first)
	context->ra_time = 0;
	context->flags \|= CONTEXT_RA_DONE;
	do_prefix = 1;
	}

	param->first = 0;
	param->found_context = 1;
	}

	/* configured time is ceiling */
	if (!constructed \|\| valid > time)
	valid = time;

	if (flags & IFACE_DEPRECATED)
	preferred = 0;

	if (deprecate)
	time = 0;

	/* configured time is ceiling */
	if (!constructed \|\| preferred > time)
	preferred = time;

	if (preferred > param->pref_time)
	{
	param->pref_time = preferred;
	param->link_global = *local;
	}

	if (do_prefix)
	{
	struct prefix_opt *opt;

	if ((opt = expand(sizeof(struct prefix_opt))))
	{
	/* zero net part of address */
	setaddr6part(local, addr6part(local) & ~((prefix == 64) ? (u64)-1LL : (1LLU << (128 - prefix)) - 1LLU));

	opt->type = ICMP6_OPT_PREFIX;
	opt->len = 4;
	opt->prefix_len = prefix;
	/* autonomous only if we're not doing dhcp, always set "on-link" */
	opt->flags = do_slaac ? 0xC0 : 0x80;
	opt->valid_lifetime = htonl(valid);
	opt->preferred_lifetime = htonl(preferred);
	opt->reserved = 0;
	opt->prefix = *local;

	inet_ntop(AF_INET6, local, daemon->addrbuff, ADDRSTRLEN);
	my_syslog(MS_DHCP \| LOG_INFO, "RTR-ADVERT(%s) %s", param->if_name, daemon->addrbuff);
	}
	}
	}
	}
	return 1;
	}

	static int add_lla(int index, unsigned int type, char mac, size_t maclen, void parm)
	{
	(void)type;

	if (index == ((int )parm))
	{
	/* size is in units of 8 octets and includes type and length (2 bytes)
	add 7 to round up */
	int len = (maclen + 9) >> 3;
	unsigned char *p = expand(len << 3);
	memset(p, 0, len << 3);
	*p++ = ICMP6_OPT_SOURCE_MAC;
	*p++ = len;
	memcpy(p, mac, maclen);

	return 0;
	}

	return 1;
	}

	time_t periodic_ra(time_t now)
	{
	struct search_param param;
	struct dhcp_context *context;
	time_t next_event;
	char interface[IF_NAMESIZE+1];

	param.now = now;
	param.iface = 0;

	while (1)
	{
	/* find overdue events, and time of first future event */
	for (next_event = 0, context = daemon->dhcp6; context; context = context->next)
	if (context->ra_time != 0)
	{
	if (difftime(context->ra_time, now) <= 0.0)
	break; /* overdue */

	if (next_event == 0 \|\| difftime(next_event, context->ra_time) > 0.0)
	next_event = context->ra_time;
	}

	/* none overdue */
	if (!context)
	break;

	/* There's a context overdue, but we can't find an interface
	associated with it, because it's for a subnet we dont
	have an interface on. Probably we're doing DHCP on
	a remote subnet via a relay. Zero the timer, since we won't
	ever be able to send ra's and satistfy it. */
	if (iface_enumerate(AF_INET6, &param, iface_search))
	context->ra_time = 0;
	else if (param.iface != 0 &&
	indextoname(daemon->icmp6fd, param.iface, interface) &&
	iface_check(AF_LOCAL, NULL, interface, NULL))
	{
	struct iname *tmp;
	for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next)
	if (tmp->name && (strcmp(tmp->name, interface) == 0))
	break;
	if (!tmp)
	send_ra(now, param.iface, interface, NULL);
	}
	}
	return next_event;
	}

	static int iface_search(struct in6_addr *local, int prefix,
	int scope, int if_index, int flags,
	int preferred, int valid, void *vparam)
	{
	struct search_param *param = vparam;
	struct dhcp_context *context;

	(void)scope;
	(void)preferred;
	(void)valid;

	for (context = daemon->dhcp6; context; context = context->next)
	if (!(context->flags & CONTEXT_TEMPLATE) &&
	prefix == context->prefix &&
	is_same_net6(local, &context->start6, prefix) &&
	is_same_net6(local, &context->end6, prefix) &&
	context->ra_time != 0 &&
	difftime(context->ra_time, param->now) <= 0.0)
	{
	/* found an interface that's overdue for RA determine new
	timeout value and arrange for RA to be sent unless interface is
	still doing DAD.*/

	if (!(flags & IFACE_TENTATIVE))
	param->iface = if_index;

	if (difftime(param->now, context->ra_short_period_start) < 60.0)
	/* range 5 - 20 */
	context->ra_time = param->now + 5 + (rand16()/4400);
	else
	/* range 450 - 600 */
	context->ra_time = param->now + 450 + (rand16()/440);

	/* zero timers for other contexts on the same subnet, so they don't timeout
	independently */
	for (context = context->next; context; context = context->next)
	if (prefix == context->prefix &&
	is_same_net6(local, &context->start6, prefix) &&
	is_same_net6(local, &context->end6, prefix))
	context->ra_time = 0;

	return 0; /* found, abort */
	}

	return 1; /* keep searching */
	}


	#endif