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 transaction which is in ping-wait
    It therefore cannot use any DHCP buffer resources except outpacket, which is
    not used by DHCPv4 code. */

 #include "dnsmasq.h"
 #include <netinet/icmp6.h>

 #ifdef HAVE_DHCP6

 struct ra_param {
   int ind, managed, found_context, first;
   char *if_name;
   struct in6_addr link_local;
 };

 struct search_param {
   time_t now; int iface;
 };

 static void send_ra(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 dad, void *vparam);
 static int iface_search(struct in6_addr *local,  int prefix,
 			int scope, int if_index, int dad, void *vparam);
 static int add_lla(int index, unsigned int type, char *mac, size_t maclen, void *parm);

 static int unicast_hop_limit, multicast_hop_limit;
 static time_t ra_short_period_start;

 void ra_init(time_t now)
 {
   struct dhcp_context *context;
   struct icmp6_filter filter;
   int fd;
 #if defined(IP_TOS) && defined(IPTOS_CLASS_CS6)
   int class = IPTOS_CLASS_CS6;
 #endif
   int val = 255; /* radvd uses this value */
   size_t len1 = sizeof(int);
   size_t len2 = sizeof(int);

   ICMP6_FILTER_SETBLOCKALL(&filter);
   ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filter);
   ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filter);

   if ((fd = socket(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) == -1 ||
       getsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &unicast_hop_limit, &len1) ||
       getsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &multicast_hop_limit, &len2) ||
 #if defined(IP_TOS) && 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;

    /* link the DHCP6 contexts to the ra-only ones so we can traverse them all
       from ->ra_contexts, but only the non-ra-onlies from ->dhcp6 */
    if (!daemon->ra_contexts)
      daemon->ra_contexts = daemon->dhcp6;
    else
      {
        for (context = daemon->ra_contexts; context->next; context = context->next);
        context->next = daemon->dhcp6;
      }

    if (!daemon->dhcp6)
      die(_("cannot do router advertisement unless DHCPv6 is enabled"), NULL, EC_BADCONF);

    ra_start_unsolicted(now);
 }

 void ra_start_unsolicted(time_t now)
 {
    struct dhcp_context *context;

    /* init timers so that we do ra's for 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 */

    /* range 0 - 5 */
    for (context = daemon->ra_contexts; context; context = context->next)
      context->ra_time = now + (rand16()/13000);

    /* re-do ras after a short time, in case the first gets lost.
       This is reset once that's done. */
    ra_short_period_start = now;
 }

 void icmp6_packet(void)
 {
   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 *p;
   char *mac = "";
   struct iname *tmp;
   struct dhcp_context *context;

   /* 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;

   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))
     return;

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

   /* weird libvirt-inspired access control */
   for (context = daemon->dhcp6; context; context = context->next)
     if (!context->interface || strcmp(context->interface, interface) == 0)
       break;

   if (!context)
     return;

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

   if (p[0] != ICMP6_ROUTER_SOLICIT || p[1] != 0)
     return;

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

   my_syslog(MS_DHCP | LOG_INFO, "RTR-SOLICIT(%s) %s", interface, mac);

   send_ra(if_index, interface, &from.sin6_addr);
 }

 static void send_ra(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;

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

   ra->type = ICMP6_ROUTER_ADVERT;
   ra->code = 0;
   ra->hop_limit = dest ? unicast_hop_limit : multicast_hop_limit;
   ra->flags = 0;
   ra->lifetime = htons(1800); /* AdvDefaultLifetime*/
   ra->reachable_time = 0;
   ra->retrans_time = 0;

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

   for (context = daemon->ra_contexts; context; context = context->next)
     context->flags &= ~CONTEXT_RA_DONE;

   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 */
   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_local, IN6ADDRSZ);


   /* set managed bits unless we're providing only RA on this link */
   if (parm.managed)
     ra->flags = 0xc0;

   /* decide where we're sending */
   memset(&addr, 0, sizeof(addr));
   addr.sin6_family = AF_INET6;
   addr.sin6_port = htons(IPPROTO_ICMPV6);
   if (dest)
     {
       memcpy(&addr.sin6_addr, dest, sizeof(struct in6_addr));
       if (IN6_IS_ADDR_LINKLOCAL(dest) ||
 	  IN6_IS_ADDR_MC_LINKLOCAL(dest))
 	addr.sin6_scope_id = iface;
     }
   else
     inet_pton(AF_INET6, ALL_HOSTS, &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 dad, void *vparam)
 {
   struct dhcp_context *context, *tmp;
   struct ra_param *param = vparam;
   struct prefix_opt *opt;

   (void)scope; /* warning */
   (void)dad;

   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_LINKLOCAL(local) &&
 	       !IN6_IS_ADDR_MULTICAST(local))
 	{
 	  for (context = daemon->ra_contexts; context; context = context->next)
 	    if (prefix == context->prefix &&
 		is_same_net6(local, &context->start6, prefix) &&
 		is_same_net6(local, &context->end6, prefix))
 	      {
 		if (!(context->flags & CONTEXT_RA_ONLY))
 		  param->managed = 1;

 		if (context->flags & CONTEXT_RA_DONE)
 		  continue;

 		/* subsequent prefixes on the same interface don't need timers */
 		if (!param->first)
 		  context->ra_time = 0;
 		param->first = 0;
 		param->found_context = 1;
 		context->flags |= CONTEXT_RA_DONE;

 		/* mark this subnet and duplicates: as done. */
 		for (tmp = context->next; tmp; tmp = tmp->next)
 		  if (tmp->prefix == prefix &&
 		      is_same_net6(local, &tmp->start6, prefix) &&
 		      is_same_net6(local, &tmp->end6, prefix))
 		    {
 		      tmp->flags |= CONTEXT_RA_DONE;
 		      context->ra_time = 0;
 		    }

 		if ((opt = expand(sizeof(struct prefix_opt))))
 		  {
 		    u64 addrpart = addr6part(&context->start6);
 		    u64 mask = (prefix == 64) ? (u64)-1LL : (1LLU << (128 - prefix)) - 1LLU;
 		    unsigned int time = context->lease_time;

 		    /* lifetimes must be min 2 hrs, by RFC 2462 */
 		    if (time < 7200)
 		      time = 7200;

 		    opt->type = ICMP6_OPT_PREFIX;
 		    opt->len = 4;
 		    opt->prefix_len = prefix;
 		    /* autonomous only is we're not doing dhcp */
 		    opt->flags = (context->flags & CONTEXT_RA_ONLY) ? 0xc0 : 0x00;
 		    opt->valid_lifetime = opt->preferred_lifetime = htonl(time);
 		    opt->reserved = 0;

 		    opt->prefix = context->start6;
 		    setaddr6part(&opt->prefix, addrpart & ~mask);

 		    inet_ntop(AF_INET6, &opt->prefix, 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;

   while (1)
     {
       /* find overdue events, and time of first future event */
       for (next_event = 0, context = daemon->ra_contexts; 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 + 2) > 0.0)
 	      next_event = context->ra_time + 2;
 	  }

       /* 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 (indextoname(daemon->icmp6fd, param.iface, interface))
 	send_ra(param.iface, interface, NULL);
     }

   return next_event;
 }

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

   (void)scope;
   (void)dad;

   for (context = daemon->ra_contexts; context; context = context->next)
     if (prefix == context->prefix &&
 	is_same_net6(local, &context->start6, prefix) &&
 	is_same_net6(local, &context->end6, prefix))
       if (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 zap other contexts on the same interface
 	     so they don't timeout independently .*/
 	  param->iface = if_index;

 	  if (difftime(param->now, 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);

 	  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 transaction which is in ping-wait
	It therefore cannot use any DHCP buffer resources except outpacket, which is
	not used by DHCPv4 code. */

	#include "dnsmasq.h"
	#include <netinet/icmp6.h>

	#ifdef HAVE_DHCP6

	struct ra_param {
	int ind, managed, found_context, first;
	char *if_name;
	struct in6_addr link_local;
	};

	struct search_param {
	time_t now; int iface;
	};

	static void send_ra(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 dad, void *vparam);
	static int iface_search(struct in6_addr *local, int prefix,
	int scope, int if_index, int dad, void *vparam);
	static int add_lla(int index, unsigned int type, char mac, size_t maclen, void parm);

	static int unicast_hop_limit, multicast_hop_limit;
	static time_t ra_short_period_start;

	void ra_init(time_t now)
	{
	struct dhcp_context *context;
	struct icmp6_filter filter;
	int fd;
	#if defined(IP_TOS) && defined(IPTOS_CLASS_CS6)
	int class = IPTOS_CLASS_CS6;
	#endif
	int val = 255; /* radvd uses this value */
	size_t len1 = sizeof(int);
	size_t len2 = sizeof(int);

	ICMP6_FILTER_SETBLOCKALL(&filter);
	ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filter);
	ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filter);

	if ((fd = socket(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) == -1 \|\|
	getsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &unicast_hop_limit, &len1) \|\|
	getsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &multicast_hop_limit, &len2) \|\|
	#if defined(IP_TOS) && 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;

	/* link the DHCP6 contexts to the ra-only ones so we can traverse them all
	from ->ra_contexts, but only the non-ra-onlies from ->dhcp6 */
	if (!daemon->ra_contexts)
	daemon->ra_contexts = daemon->dhcp6;
	else
	{
	for (context = daemon->ra_contexts; context->next; context = context->next);
	context->next = daemon->dhcp6;
	}

	if (!daemon->dhcp6)
	die(_("cannot do router advertisement unless DHCPv6 is enabled"), NULL, EC_BADCONF);

	ra_start_unsolicted(now);
	}

	void ra_start_unsolicted(time_t now)
	{
	struct dhcp_context *context;

	/* init timers so that we do ra's for 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 */

	/* range 0 - 5 */
	for (context = daemon->ra_contexts; context; context = context->next)
	context->ra_time = now + (rand16()/13000);

	/* re-do ras after a short time, in case the first gets lost.
	This is reset once that's done. */
	ra_short_period_start = now;
	}

	void icmp6_packet(void)
	{
	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 *p;
	char *mac = "";
	struct iname *tmp;
	struct dhcp_context *context;

	/* 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;

	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))
	return;

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

	/* weird libvirt-inspired access control */
	for (context = daemon->dhcp6; context; context = context->next)
	if (!context->interface \|\| strcmp(context->interface, interface) == 0)
	break;

	if (!context)
	return;

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

	if (p[0] != ICMP6_ROUTER_SOLICIT \|\| p[1] != 0)
	return;

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

	my_syslog(MS_DHCP \| LOG_INFO, "RTR-SOLICIT(%s) %s", interface, mac);

	send_ra(if_index, interface, &from.sin6_addr);
	}

	static void send_ra(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;

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

	ra->type = ICMP6_ROUTER_ADVERT;
	ra->code = 0;
	ra->hop_limit = dest ? unicast_hop_limit : multicast_hop_limit;
	ra->flags = 0;
	ra->lifetime = htons(1800); /* AdvDefaultLifetime*/
	ra->reachable_time = 0;
	ra->retrans_time = 0;

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

	for (context = daemon->ra_contexts; context; context = context->next)
	context->flags &= ~CONTEXT_RA_DONE;

	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 */
	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_local, IN6ADDRSZ);


	/* set managed bits unless we're providing only RA on this link */
	if (parm.managed)
	ra->flags = 0xc0;

	/* decide where we're sending */
	memset(&addr, 0, sizeof(addr));
	addr.sin6_family = AF_INET6;
	addr.sin6_port = htons(IPPROTO_ICMPV6);
	if (dest)
	{
	memcpy(&addr.sin6_addr, dest, sizeof(struct in6_addr));
	if (IN6_IS_ADDR_LINKLOCAL(dest) \|\|
	IN6_IS_ADDR_MC_LINKLOCAL(dest))
	addr.sin6_scope_id = iface;
	}
	else
	inet_pton(AF_INET6, ALL_HOSTS, &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 dad, void *vparam)
	{
	struct dhcp_context context, tmp;
	struct ra_param *param = vparam;
	struct prefix_opt *opt;

	(void)scope; /* warning */
	(void)dad;

	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_LINKLOCAL(local) &&
	!IN6_IS_ADDR_MULTICAST(local))
	{
	for (context = daemon->ra_contexts; context; context = context->next)
	if (prefix == context->prefix &&
	is_same_net6(local, &context->start6, prefix) &&
	is_same_net6(local, &context->end6, prefix))
	{
	if (!(context->flags & CONTEXT_RA_ONLY))
	param->managed = 1;

	if (context->flags & CONTEXT_RA_DONE)
	continue;

	/* subsequent prefixes on the same interface don't need timers */
	if (!param->first)
	context->ra_time = 0;
	param->first = 0;
	param->found_context = 1;
	context->flags \|= CONTEXT_RA_DONE;

	/* mark this subnet and duplicates: as done. */
	for (tmp = context->next; tmp; tmp = tmp->next)
	if (tmp->prefix == prefix &&
	is_same_net6(local, &tmp->start6, prefix) &&
	is_same_net6(local, &tmp->end6, prefix))
	{
	tmp->flags \|= CONTEXT_RA_DONE;
	context->ra_time = 0;
	}

	if ((opt = expand(sizeof(struct prefix_opt))))
	{
	u64 addrpart = addr6part(&context->start6);
	u64 mask = (prefix == 64) ? (u64)-1LL : (1LLU << (128 - prefix)) - 1LLU;
	unsigned int time = context->lease_time;

	/* lifetimes must be min 2 hrs, by RFC 2462 */
	if (time < 7200)
	time = 7200;

	opt->type = ICMP6_OPT_PREFIX;
	opt->len = 4;
	opt->prefix_len = prefix;
	/* autonomous only is we're not doing dhcp */
	opt->flags = (context->flags & CONTEXT_RA_ONLY) ? 0xc0 : 0x00;
	opt->valid_lifetime = opt->preferred_lifetime = htonl(time);
	opt->reserved = 0;

	opt->prefix = context->start6;
	setaddr6part(&opt->prefix, addrpart & ~mask);

	inet_ntop(AF_INET6, &opt->prefix, 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;

	while (1)
	{
	/* find overdue events, and time of first future event */
	for (next_event = 0, context = daemon->ra_contexts; 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 + 2) > 0.0)
	next_event = context->ra_time + 2;
	}

	/* 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 (indextoname(daemon->icmp6fd, param.iface, interface))
	send_ra(param.iface, interface, NULL);
	}

	return next_event;
	}

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

	(void)scope;
	(void)dad;

	for (context = daemon->ra_contexts; context; context = context->next)
	if (prefix == context->prefix &&
	is_same_net6(local, &context->start6, prefix) &&
	is_same_net6(local, &context->end6, prefix))
	if (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 zap other contexts on the same interface
	so they don't timeout independently .*/
	param->iface = if_index;

	if (difftime(param->now, 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);

	return 0; /* found, abort */
	}

	return 1; /* keep searching */
	}

	#endif