From 5bf50af2d028325518fcba049d705832d2991eac Mon Sep 17 00:00:00 2001
From: Ilya Ponetaev <iponetaev@dlink.ru>
Date: Tue, 9 Sep 2014 12:46:21 +0100
Subject: RFC4191 route information option.

---
 CHANGELOG           |  4 ++++
 src/radv-protocol.h |  1 +
 src/radv.c          | 51 +++++++++++++++++++++++++++++++++++++++------------
 3 files changed, 44 insertions(+), 12 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index 62f2e4a..d709adf 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -27,6 +27,10 @@ version 2.72
 	    servers which loop back are disabled and this event is logged.
 	    Thanks to Smoothwall for their sponsorship of this feature.
 
+	    Include an RFC4191 route information option in router 
+	    advertisements for the prefix we're advertising. Thanks to 
+	    Ilya Ponetaev for the patch.
+ 
 
 version 2.71
             Subtle change to error handling to help DNSSEC validation 
diff --git a/src/radv-protocol.h b/src/radv-protocol.h
index e576012..72ccda4 100644
--- a/src/radv-protocol.h
+++ b/src/radv-protocol.h
@@ -50,6 +50,7 @@ struct prefix_opt {
 #define ICMP6_OPT_PREFIX       3
 #define ICMP6_OPT_MTU          5
 #define ICMP6_OPT_ADV_INTERVAL 7
+#define ICMP6_OPT_RT_INFO     24
 #define ICMP6_OPT_RDNSS       25
 #define ICMP6_OPT_DNSSL       31
 
diff --git a/src/radv.c b/src/radv.c
index f5b517b..87ddfae 100644
--- a/src/radv.c
+++ b/src/radv.c
@@ -32,7 +32,7 @@ struct ra_param {
   char *if_name;
   struct dhcp_netid *tags;
   struct in6_addr link_local, link_global, ula;
-  unsigned int glob_pref_time, link_pref_time, ula_pref_time, adv_interval;
+  unsigned int glob_pref_time, link_pref_time, ula_pref_time, adv_interval, prio;
 };
 
 struct search_param {
@@ -210,18 +210,7 @@ static void send_ra(time_t now, int iface, char *iface_name, struct in6_addr *de
 #ifdef HAVE_LINUX_NETWORK
   FILE *f;
 #endif
- 
-  save_counter(0);
-  ra = expand(sizeof(struct ra_packet));
   
-  ra->type = ND_ROUTER_ADVERT;
-  ra->code = 0;
-  ra->hop_limit = hop_limit;
-  ra->flags = calc_prio(ra_param);
-  ra->lifetime = htons(calc_lifetime(ra_param));
-  ra->reachable_time = 0;
-  ra->retrans_time = 0;
-
   parm.ind = iface;
   parm.managed = 0;
   parm.other = 0;
@@ -232,7 +221,19 @@ static void send_ra(time_t now, int iface, char *iface_name, struct in6_addr *de
   parm.now = now;
   parm.glob_pref_time = parm.link_pref_time = parm.ula_pref_time = 0;
   parm.adv_interval = calc_interval(ra_param);
+  parm.prio = calc_prio(ra_param);
+  
+  save_counter(0);
+  ra = expand(sizeof(struct ra_packet));
   
+  ra->type = ND_ROUTER_ADVERT;
+  ra->code = 0;
+  ra->hop_limit = hop_limit;
+  ra->flags = parm.prio;
+  ra->lifetime = htons(calc_lifetime(ra_param));
+  ra->reachable_time = 0;
+  ra->retrans_time = 0;
+
   /* set tag with name == interface */
   iface_id.net = iface_name;
   iface_id.next = NULL;
@@ -648,6 +649,32 @@ static int add_prefixes(struct in6_addr *local,  int prefix,
 		  inet_ntop(AF_INET6, local, daemon->addrbuff, ADDRSTRLEN);
 		  if (!option_bool(OPT_QUIET_RA))
 		    my_syslog(MS_DHCP | LOG_INFO, "RTR-ADVERT(%s) %s", param->if_name, daemon->addrbuff); 		    
+		  
+		  /* Send Route Information option (RFC4191, 2.3) */
+		  put_opt6_char(ICMP6_OPT_RT_INFO);
+		  /* Length in units of 8 octets will be 1 (header) +
+		   * 0, 1 or 2 (0...128 bits / 64 bit per unit) */
+		  if (0 == prefix)
+		    put_opt6_char(1);
+		  else if (prefix < 65) 
+		    put_opt6_char(2);
+		  else
+		    put_opt6_char(3);
+		  
+		  put_opt6_char(prefix);
+		  /* Same priority and advertised prefix */
+		  put_opt6_char(param->prio);
+		  /* "valid lifetime" seems more reasonable than "preferred" */
+		  put_opt6_long(valid);
+		  /* Actual prefix, only necessary part
+		   * Don't append any data in case of prefix length == 0  */
+		  if (0 != prefix) 
+		    {
+		      if (prefix < 65)
+			put_opt6((void *)local, 8);
+		      else
+			put_opt6((void *)local, 16);
+		    }
 		}
 	    }
 	}
-- 
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