[Dnsmasq-discuss] [PATCH] Don't advertise a default v6 route with no routeable prefixes

[Chris Webb]

When we are only advertising old v6 prefixes, we currently set the router
lifetime to zero in radv.c. This instructs automatically configured
clients not to configure a default v6 route pointing at us.

If we are advertising local (ULA) prefixes but no globally-routeable
prefixes, we should similarly not configure clients with a default route.
Set the router lifetime to zero in this case too.

Signed-off-by: Chris Webb <chris at arachsys.com>
---
 src/radv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/radv.c b/src/radv.c
index 5820f4a..16737c4 100644
--- a/src/radv.c
+++ b/src/radv.c
@@ -402,8 +402,8 @@ static void send_ra_alias(time_t now, int iface, char *iface_name, struct in6_ad
 	up = &context->next;
     }
     
-  /* If we're advertising only old prefixes, set router lifetime to zero. */
-  if (old_prefix && !parm.found_context)
+  /* If we're advertising only local or old prefixes, set router lifetime to zero. */
+  if ((old_prefix && !parm.found_context) || parm.glob_pref_time == 0)
     ra->lifetime = htons(0);
 
   /* No prefixes to advertise. */