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.

5 files changed, 65 insertions, 50 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);
diff --git a/proto/babel/babel.c b/proto/babel/babel.c
index 12c9a474..b4e42a9a 100644
--- a/proto/babel/babel.c
+++ b/proto/babel/babel.c
@@ -846,8 +846,7 @@ babel_send_route_request(struct babel_proto *p, struct babel_entry *e, struct ba
 {
   union babel_msg msg = {};
 
-  TRACE(D_PACKETS, "Sending route request for %N to %I",
-        e->n.addr, n->addr);
+  TRACE(D_PACKETS, "Sending route request for %N to %I", e->n.addr, n->addr);
 
   msg.type = BABEL_TLV_ROUTE_REQUEST;
   net_copy(&msg.route_request.net, e->n.addr);
@@ -861,8 +860,7 @@ babel_send_wildcard_request(struct babel_iface *ifa)
   struct babel_proto *p = ifa->proto;
   union babel_msg msg = {};
 
-  TRACE(D_PACKETS, "Sending wildcard route request on %s",
-	ifa->ifname);
+  TRACE(D_PACKETS, "Sending wildcard route request on %s", ifa->ifname);
 
   msg.type = BABEL_TLV_ROUTE_REQUEST;
   msg.route_request.full = 1;
@@ -1516,6 +1514,21 @@ babel_iface_update_state(struct babel_iface *ifa)
 }
 
 static void
+babel_iface_update_addr4(struct babel_iface *ifa)
+{
+  struct babel_proto *p = ifa->proto;
+
+  ip_addr addr4 = ifa->iface->addr4 ? ifa->iface->addr4->ip : IPA_NONE;
+  ifa->next_hop_ip4 = ipa_nonzero(ifa->cf->next_hop_ip4) ? ifa->cf->next_hop_ip4 : addr4;
+
+  if (ipa_zero(ifa->next_hop_ip4) && p->ip4_channel)
+    log(L_WARN "%s: Missing IPv4 next hop address for %s", p->p.name, ifa->ifname);
+
+  if (ifa->up)
+    babel_iface_kick_timer(ifa);
+}
+
+static void
 babel_iface_update_buffers(struct babel_iface *ifa)
 {
   if (!ifa->sk)
@@ -1624,15 +1637,21 @@ babel_if_notify(struct proto *P, unsigned flags, struct iface *iface)
 {
   struct babel_proto *p = (void *) P;
   struct babel_config *cf = (void *) P->cf;
+  struct babel_iface *ifa = babel_find_iface(p, iface);
 
   if (iface->flags & IF_IGNORE)
     return;
 
-  if (flags & IF_CHANGE_UP)
+  /* Add, remove or restart interface */
+  if (flags & (IF_CHANGE_UPDOWN | IF_CHANGE_LLV6))
   {
-    struct babel_iface_config *ic = (void *) iface_patt_find(&cf->iface_list, iface, NULL);
+    if (ifa)
+      babel_remove_iface(p, ifa);
+
+    if (!(iface->flags & IF_UP))
+      return;
 
-    /* we only speak multicast */
+    /* We only speak multicast */
     if (!(iface->flags & IF_MULTICAST))
       return;
 
@@ -1640,22 +1659,18 @@ babel_if_notify(struct proto *P, unsigned flags, struct iface *iface)
     if (!iface->llv6)
       return;
 
+    struct babel_iface_config *ic = (void *) iface_patt_find(&cf->iface_list, iface, NULL);
     if (ic)
       babel_add_iface(p, iface, ic);
 
     return;
   }
 
-  struct babel_iface *ifa = babel_find_iface(p, iface);
-
   if (!ifa)
     return;
 
-  if (flags & IF_CHANGE_DOWN)
-  {
-    babel_remove_iface(p, ifa);
-    return;
-  }
+  if (flags & IF_CHANGE_ADDR4)
+    babel_iface_update_addr4(ifa);
 
   if (flags & IF_CHANGE_MTU)
     babel_iface_update_buffers(ifa);
diff --git a/proto/radv/radv.c b/proto/radv/radv.c
index a381f737..12d90823 100644
--- a/proto/radv/radv.c
+++ b/proto/radv/radv.c
@@ -330,13 +330,19 @@ radv_if_notify(struct proto *P, unsigned flags, struct iface *iface)
 {
   struct radv_proto *p = (struct radv_proto *) P;
   struct radv_config *cf = (struct radv_config *) (P->cf);
+  struct radv_iface *ifa = radv_iface_find(p, iface);
 
   if (iface->flags & IF_IGNORE)
     return;
 
-  if (flags & IF_CHANGE_UP)
+  /* Add, remove or restart interface */
+  if (flags & (IF_CHANGE_UPDOWN | IF_CHANGE_LLV6))
   {
-    struct radv_iface_config *ic = (void *) iface_patt_find(&cf->patt_list, iface, NULL);
+    if (ifa)
+      radv_iface_remove(ifa);
+
+    if (!(iface->flags & IF_UP))
+      return;
 
     /* Ignore non-multicast ifaces */
     if (!(iface->flags & IF_MULTICAST))
@@ -346,22 +352,16 @@ radv_if_notify(struct proto *P, unsigned flags, struct iface *iface)
     if (!iface->llv6)
       return;
 
+    struct radv_iface_config *ic = (void *) iface_patt_find(&cf->patt_list, iface, NULL);
     if (ic)
       radv_iface_new(p, iface, ic);
 
     return;
   }
 
-  struct radv_iface *ifa = radv_iface_find(p, iface);
   if (!ifa)
     return;
 
-  if (flags & IF_CHANGE_DOWN)
-  {
-    radv_iface_remove(ifa);
-    return;
-  }
-
   if ((flags & IF_CHANGE_LINK) && (iface->flags & IF_LINK_UP))
     radv_iface_notify(ifa, RA_EV_INIT);
 }
diff --git a/proto/rip/rip.c b/proto/rip/rip.c
index 2838d425..612b6f92 100644
--- a/proto/rip/rip.c
+++ b/proto/rip/rip.c
@@ -746,35 +746,34 @@ rip_if_notify(struct proto *P, unsigned flags, struct iface *iface)
 {
   struct rip_proto *p = (void *) P;
   struct rip_config *cf = (void *) P->cf;
+  struct rip_iface *ifa = rip_find_iface(p, iface);
 
   if (iface->flags & IF_IGNORE)
     return;
 
-  if (flags & IF_CHANGE_UP)
+  /* Add, remove or restart interface */
+  if (flags & (IF_CHANGE_UPDOWN | (rip_is_v2(p) ? IF_CHANGE_ADDR4 : IF_CHANGE_LLV6)))
   {
-    struct rip_iface_config *ic = (void *) iface_patt_find(&cf->patt_list, iface, NULL);
+    if (ifa)
+      rip_remove_iface(p, ifa);
+
+    if (!(iface->flags & IF_UP))
+      return;
 
     /* Ignore ifaces without appropriate address */
     if (rip_is_v2(p) ? !iface->addr4 : !iface->llv6)
       return;
 
+    struct rip_iface_config *ic = (void *) iface_patt_find(&cf->patt_list, iface, NULL);
     if (ic)
       rip_add_iface(p, iface, ic);
 
     return;
   }
 
-  struct rip_iface *ifa = rip_find_iface(p, iface);
-
   if (!ifa)
     return;
 
-  if (flags & IF_CHANGE_DOWN)
-  {
-    rip_remove_iface(p, ifa);
-    return;
-  }
-
   if (flags & IF_CHANGE_MTU)
     rip_iface_update_buffers(ifa);