Nest: Do not hard-reset interface when preferred address is changed

Modify protocols to use preferred address change notification instead on
depending on hard-reset of interfaces in that case, and remove hard-reset
in that case. This avoids issue when e.g. IPv6 protocol restarts
interface when IPv4 preferred address changed (as hard-reset is
unavoidable and common for whole iface).

The patch also fixes a bug when removing last address does not send
preferred address change notification.

2 files changed, 18 insertions, 17 deletions

diff --git a/nest/iface.c b/nest/iface.c
index 23a82ac5..c1966ac6 100644
--- a/nest/iface.c
+++ b/nest/iface.c
@@ -526,32 +526,28 @@ if_recalc_preferred(struct iface *i)
       }
     }
 
-  if (a4 != i->addr4)
+  if ((a4 != i->addr4) || (i->flags & IF_LOST_ADDR4))
   {
     if_set_preferred(&i->addr4, a4);
     change |= IF_CHANGE_ADDR4;
   }
 
-  if (a6 != i->addr6)
+  if ((a6 != i->addr6) || (i->flags & IF_LOST_ADDR6))
   {
     if_set_preferred(&i->addr6, a6);
     change |= IF_CHANGE_ADDR6;
   }
 
-  if (ll != i->llv6)
+  if ((ll != i->llv6) || (i->flags & IF_LOST_LLV6))
   {
     if_set_preferred(&i->llv6, ll);
     change |= IF_CHANGE_LLV6;
   }
 
-  i->flags &= ~IF_NEEDS_RECALC;
+  i->flags &= ~(IF_NEEDS_RECALC | IF_LOST_ADDR4 | IF_LOST_ADDR6 | IF_LOST_LLV6);
 
-  /*
-   * FIXME: There should be proper notification instead of iface restart:
-   * if_notify_change(change, i)
-   */
   if (change)
-    if_change_flags(i, i->flags | IF_TMP_DOWN);
+    if_notify_change(change, i);
 }
 
 void
@@ -643,11 +639,12 @@ ifa_delete(struct ifa *a)
 	     * We unlink deleted preferred address and mark for recalculation.
 	     * FIXME: This could break if we make iface scan non-atomic, as
 	     * protocols still could use the freed address until they get
-	     * if_notify from preferred route recalculation.
+	     * if_notify from preferred route recalculation. We should fix and
+	     * simplify this in the future by having struct ifa refcounted
 	     */
-	    if (b == i->addr4) i->addr4 = NULL;
-	    if (b == i->addr6) i->addr6 = NULL;
-	    if (b == i->llv6) i->llv6 = NULL;
+	    if (b == i->addr4) { i->addr4 = NULL; i->flags |= IF_LOST_ADDR4; }
+	    if (b == i->addr6) { i->addr6 = NULL; i->flags |= IF_LOST_ADDR6; }
+	    if (b == i->llv6)  { i->llv6 = NULL;  i->flags |= IF_LOST_LLV6; }
 	    i->flags |= IF_NEEDS_RECALC;
 	  }
 
diff --git a/nest/iface.h b/nest/iface.h
index bc241501..0eb277cd 100644
--- a/nest/iface.h
+++ b/nest/iface.h
@@ -73,12 +73,15 @@ struct iface {
  */
 
 
-#define IF_JUST_CREATED 0x10000000	/* Send creation event as soon as possible */
-#define IF_TMP_DOWN 0x20000000		/* Temporary shutdown due to interface reconfiguration */
-#define IF_UPDATED 0x40000000		/* Iface touched in last scan */
+#define IF_JUST_CREATED	0x10000000	/* Send creation event as soon as possible */
+#define IF_TMP_DOWN	0x20000000	/* Temporary shutdown due to interface reconfiguration */
+#define IF_UPDATED	0x40000000	/* Iface touched in last scan */
 #define IF_NEEDS_RECALC	0x80000000	/* Preferred address recalculation is needed */
+#define IF_LOST_ADDR4	0x01000000	/* Preferred address was deleted, notification needed */
+#define IF_LOST_ADDR6	0x02000000
+#define IF_LOST_LLV6	0x04000000
 
-#define IA_UPDATED IF_UPDATED		/* Address touched in last scan */
+#define IA_UPDATED	IF_UPDATED	/* Address touched in last scan */
 
 /* Interface change events */
 
@@ -93,6 +96,7 @@ struct iface {
 #define IF_CHANGE_SYSDEP 0x800
 #define IF_CHANGE_TOO_MUCH 0x40000000	/* Used internally */
 
+#define IF_CHANGE_UPDOWN (IF_CHANGE_UP | IF_CHANGE_DOWN)
 #define IF_CHANGE_PREFERRED (IF_CHANGE_ADDR4 | IF_CHANGE_ADDR6 | IF_CHANGE_LLV6)
 
 void if_init(void);