Interface updates are asynchronous

Instead of propagating interface updates as they are loaded from kernel,
they are enqueued and all the notifications are called from a
protocol-specific event. This change allows to break the locking loop
between protocols and interfaces.

Anyway, this change is based on v2 branch to keep the changes between v2
and v3 smaller.

1 files changed, 65 insertions, 1 deletions

diff --git a/nest/iface.h b/nest/iface.h
index fb27f99e..a3f4f30a 100644
--- a/nest/iface.h
+++ b/nest/iface.h
@@ -9,6 +9,7 @@
 #ifndef _BIRD_IFACE_H_
 #define _BIRD_IFACE_H_
 
+#include "lib/event.h"
 #include "lib/lists.h"
 #include "lib/tlists.h"
 #include "lib/ip.h"
@@ -27,6 +28,7 @@ struct ifa {				/* Interface address */
   ip_addr opposite;			/* Opposite end of a point-to-point link */
   unsigned scope;			/* Interface address scope */
   unsigned flags;			/* Analogous to iface->flags */
+  unsigned uc;				/* Use (link) count */
 };
 
 extern struct iface default_vrf;
@@ -45,6 +47,7 @@ struct iface {
   struct ifa *llv6;			/* Primary link-local address for IPv6 */
   ip4_addr sysdep;			/* Arbitrary IPv4 address for internal sysdep use */
   list neighbors;			/* All neighbors on this interface */
+  unsigned uc;				/* Use (link) count */
 };
 
 #define IF_UP 1				/* Currently just IF_ADMIN_UP */
@@ -115,12 +118,15 @@ void ifa_delete(struct ifa *);
 void if_start_update(void);
 void if_end_partial_update(struct iface *);
 void if_end_update(void);
-void if_feed_baby(struct proto *);
 struct iface *if_find_by_index(unsigned);
 struct iface *if_find_by_name(const char *);
 struct iface *if_get_by_name(const char *);
 void if_recalc_all_preferred_addresses(void);
 
+void if_link(struct iface *);
+void if_unlink(struct iface *);
+void ifa_link(struct ifa *);
+void ifa_unlink(struct ifa *);
 
 /* The Neighbor Cache */
 
@@ -138,6 +144,7 @@ typedef struct neighbor {
   u16 flags;				/* NEF_* flags */
   s16 scope;				/* Address scope, -1 for unreachable neighbors,
 					   SCOPE_HOST when it's our own address */
+  uint uc;				/* Use (link) count */
 } neighbor;
 
 #define TLIST_PREFIX proto_neigh
@@ -164,6 +171,63 @@ void neigh_ifa_up(struct ifa *a);
 void neigh_ifa_down(struct ifa *a);
 void neigh_init(struct pool *);
 
+void neigh_link(neighbor *);
+void neigh_unlink(neighbor *);
+
+/*
+ *	Notification mechanism
+ */
+
+#define TLIST_PREFIX ifnot
+#define TLIST_TYPE struct iface_notification
+#define TLIST_ITEM nn
+#define TLIST_WANT_WALK
+#define TLIST_WANT_ADD_TAIL
+
+struct iface_notification {
+  TLIST_DEFAULT_NODE;
+  enum {
+    IFNOT_INVALID,
+    IFNOT_ADDRESS,
+    IFNOT_INTERFACE,
+    IFNOT_NEIGHBOR,
+  } type;
+  unsigned flags;
+  union {
+    struct ifa *a;
+    struct iface *i;
+    neighbor *n;
+  };
+};
+
+#include "lib/tlists.h"
+
+#define TLIST_PREFIX ifsub
+#define TLIST_TYPE struct iface_subscription
+#define TLIST_ITEM n
+#define TLIST_WANT_WALK
+#define TLIST_WANT_ADD_TAIL
+
+struct iface_subscription {
+  TLIST_DEFAULT_NODE;
+
+  event event;
+  TLIST_LIST(ifnot) queue;
+
+  void (*if_notify)(struct proto *, unsigned flags, struct iface *i);
+  void (*ifa_notify)(struct proto *, unsigned flags, struct ifa *a);
+  void (*neigh_notify)(struct neighbor *neigh);
+};
+
+#include "lib/tlists.h"
+
+void if_enqueue_notify(struct iface_notification);
+void if_enqueue_notify_to(struct iface_notification x, struct iface_subscription *s);
+
+void iface_flush_notifications(struct iface_subscription *);
+void iface_subscribe(struct iface_subscription *);
+void iface_unsubscribe(struct iface_subscription *);
+
 /*
  *	Interface Pattern Lists
  */