RAdv: Support for more specific routes (RFC 4191)

The patch implements Default Router Preferences and More-Specific Routes
(RFC 4191) for RAdv protocol, allowing to announce router preference and
more specific routes in router advertisements. Routes can be exported to
RAdv like to regular routing protocols.

Some cleanups, bugfixes and other changes done by Ondrej Zajicek.

1 files changed, 29 insertions, 3 deletions

diff --git a/proto/radv/radv.h b/proto/radv/radv.h
index 60b9980f..3bc18249 100644
--- a/proto/radv/radv.h
+++ b/proto/radv/radv.h
@@ -54,6 +54,10 @@ struct radv_config
   ip_addr trigger_prefix;	/* Prefix of a trigger route, if defined */
   u8 trigger_pxlen;		/* Pxlen of a trigger route, if defined */
   u8 trigger_valid;		/* Whether a trigger route is defined */
+  u8 propagate_routes;		/* Do we propagate more specific routes (RFC 4191)? */
+  u32 route_lifetime;		/* Lifetime for the RFC 4191 routes */
+  u32 route_lifetime_sensitive; /* Whether route_lifetime depends on trigger */
+  u32 route_linger_time;	/* For how long we advertise dead routes with lifetime = 0 */
 };
 
 struct radv_iface_config
@@ -117,12 +121,32 @@ struct radv_dnssl_config
   char *domain;			/* Domain for DNS search list, in processed form */
 };
 
+/*
+ * One more specific route as per RFC 4191.
+ *
+ * Note that it does *not* contain the next hop field. The next hop is always
+ * the router sending the advertisment and the more specific route only allows
+ * overriding the preference of the route.
+ */
+struct radv_route
+{
+  struct fib_node n;
+  u32 lifetime;			/* Lifetime from an attribute */
+  u8 lifetime_set;		/* Is the lifetime set by an attribute? */
+  u8 preference;		/* Preference of the route, RA_PREF_* */
+  u8 alive;
+  bird_clock_t expires;		/* Time to remove when !alive */
+};
 
 struct radv_proto
 {
   struct proto p;
   list iface_list;		/* List of active ifaces */
+  u8 valid;			/* Router is valid for forwarding, used for shutdown */
   u8 active;			/* Whether radv is active w.r.t. triggers */
+  u8 fib_up;			/* FIB table (routes) is initialized */
+  struct fib routes;		/* FIB table of specific routes (struct radv_route) */
+  bird_clock_t prune_time;	/* Next time of route table pruning */
 };
 
 struct radv_prefix		/* One prefix we advertise */
@@ -147,7 +171,7 @@ struct radv_iface
   struct ifa *addr;		/* Link-local address of iface */
   struct pool *pool;		/* A pool for interface-specific things */
   list prefixes;		/* The prefixes we advertise (struct radv_prefix) */
-  bird_clock_t prefix_expires;	/* When the soonest prefix expires (0 = none dead) */
+  bird_clock_t prune_time;	/* Next time of prefix list pruning */
 
   timer *timer;
   struct object_lock *lock;
@@ -161,7 +185,6 @@ struct radv_iface
 #define RA_EV_INIT 1		/* Switch to initial mode */
 #define RA_EV_CHANGE 2		/* Change of options or prefixes */
 #define RA_EV_RS 3		/* Received RS */
-#define RA_EV_GC 4		/* Internal garbage collection of prefixes */
 
 /* Default Router Preferences (RFC 4191) */
 #define RA_PREF_LOW	0x18
@@ -169,6 +192,9 @@ struct radv_iface
 #define RA_PREF_HIGH	0x08
 #define RA_PREF_MASK	0x18
 
+/* Attributes */
+#define EA_RA_PREFERENCE	EA_CODE(EAP_RADV, 0)
+#define EA_RA_LIFETIME		EA_CODE(EAP_RADV, 1)
 
 #ifdef LOCAL_DEBUG
 #define RADV_FORCE_DEBUG 1
@@ -184,7 +210,7 @@ void radv_iface_notify(struct radv_iface *ifa, int event);
 
 /* packets.c */
 int radv_process_domain(struct radv_dnssl_config *cf);
-void radv_send_ra(struct radv_iface *ifa, int shutdown);
+void radv_send_ra(struct radv_iface *ifa);
 int radv_sk_open(struct radv_iface *ifa);