Handle disappearing interfaces

5 files changed, 42 insertions, 22 deletions

diff --git a/ffd/announce.c b/ffd/announce.c
index 6b30ec6..62e876a 100644
--- a/ffd/announce.c
+++ b/ffd/announce.c
@@ -45,7 +45,7 @@ static void maintain_nexthops(ffd_announce_t *announce) {
 				if (announce->selected == nexthop)
 					announce->selected = NULL;
 
-				nexthop->neigh->nexthop_refs--;
+				ffd_neigh_unref(nexthop->neigh);
 
 				free(nexthop);
 			}
@@ -54,6 +54,11 @@ static void maintain_nexthops(ffd_announce_t *announce) {
 				add_interval(&nexthop->last_update, FFD_UPDATE_TIMEOUT(nexthop->interval));
 			}
 		}
+		else if (!nexthop->neigh->iface && nexthop->metric_seqno.metric != 0xffff) {
+			nexthop->metric_seqno.metric = 0xffff;
+			nexthop->last_update = now;
+			add_interval(&nexthop->last_update, FFD_UPDATE_TIMEOUT(nexthop->interval));
+		}
 	}
 }
 
diff --git a/ffd/ffd.c b/ffd/ffd.c
index 7cc3d3f..f5b3271 100644
--- a/ffd/ffd.c
+++ b/ffd/ffd.c
@@ -170,8 +170,7 @@ static void update_netifs(void) {
 
 		if (iface->type == IF_UNSPEC) {
 			*cur = iface->next;
-
-			ffd_neigh_free_list(iface->neigh_list);
+			ffd_neigh_unref_list(iface->neigh_list);
 			free(iface);
 		}
 		else {
@@ -320,7 +319,7 @@ static ffd_nexthop_t* new_nexthop(ffd_announce_t *announce, ffd_neigh_t *neigh)
 	nexthop->next = announce->nexthop_list;
 	announce->nexthop_list = nexthop;
 
-	neigh->nexthop_refs++;
+	ffd_neigh_ref(neigh);
 
 	return nexthop;
 }
@@ -475,6 +474,8 @@ static void send_updates(void) {
 }
 
 static void maintenance(void) {
+	update_netifs();
+
 	ffd_iface_t *iface;
 	for (iface = iface_list; iface; iface = iface->next) {
 		ffd_neigh_t **cur, **next;
@@ -482,7 +483,7 @@ static void maintenance(void) {
 			ffd_neigh_t *neigh = *cur;
 			next = &neigh->next;
 
-			if (ffd_neigh_get_rxcost(neigh) == 0xffff && ffd_neigh_get_txcost(neigh) == 0xffff && !neigh->nexthop_refs) {
+			if (ffd_neigh_get_rxcost(neigh) == 0xffff && ffd_neigh_get_txcost(neigh) == 0xffff && !neigh->ref) {
 				*cur = *next;
 				next = cur;
 				free(neigh);
@@ -524,9 +525,10 @@ static void maintenance(void) {
 				continue;
 			}
 
-			fprintf(stderr, "\tnexthop: %02x:%02x:%02x:%02x:%02x:%02x (%u, seqno=%04x, cost=%u%s)\n",
+			fprintf(stderr, "\tnexthop: %02x:%02x:%02x:%02x:%02x:%02x[%s] (%u, seqno=%04x, cost=%u%s)\n",
 				neigh->addr.d[0], neigh->addr.d[1], neigh->addr.d[2],
 				neigh->addr.d[3], neigh->addr.d[4], neigh->addr.d[5],
+				neigh->iface ? neigh->iface->name : NULL,
 				nexthop->metric_seqno.metric, nexthop->metric_seqno.seqno, ffd_neigh_get_cost(neigh),
 				(nexthop == announce->selected) ? ", selected" : "");
 		}
@@ -550,7 +552,12 @@ int main() {
 	struct timespec next_maintenance = now;
 
 	while (true) {
-		update_netifs();
+		int maintenance_timeout = timespec_diff(&next_maintenance, &now);
+		if (maintenance_timeout <= 0) {
+			maintenance();
+
+			add_interval(&next_maintenance, FFD_MAINTENANCE_INTERVAL);
+		}
 
 		int hello_timeout = timespec_diff(&next_hello, &now);
 		if (hello_timeout <= 0) {
@@ -567,13 +574,6 @@ int main() {
 			add_interval(&next_update, FFD_UPDATE_INTERVAL);
 		}
 
-		int maintenance_timeout = timespec_diff(&next_maintenance, &now);
-		if (maintenance_timeout <= 0) {
-			maintenance();
-
-			add_interval(&next_maintenance, FFD_MAINTENANCE_INTERVAL);
-		}
-
 		int timeout = min(min(hello_timeout, update_timeout), maintenance_timeout);
 		if (timeout <= 0)
 			continue;
diff --git a/ffd/ffd.h b/ffd/ffd.h
index 9bd0d2c..4199000 100644
--- a/ffd/ffd.h
+++ b/ffd/ffd.h
@@ -91,10 +91,9 @@ typedef struct _ffd_announce_t {
 typedef struct _ffd_neigh_t {
 	struct _ffd_neigh_t *next;
 
-	unsigned nexthop_refs;
+	unsigned ref;
 
-	/* for actual routing, we'd also have to link back to the iface
-	   this neighbour belongs to */
+	struct _ffd_iface_t *iface;
 	eth_addr_t addr;
 
 	uint16_t hello_log;
diff --git a/ffd/neigh.c b/ffd/neigh.c
index ca72ccc..1b0d41d 100644
--- a/ffd/neigh.c
+++ b/ffd/neigh.c
@@ -32,6 +32,7 @@ ffd_neigh_t* ffd_neigh_get(ffd_iface_t *iface, const eth_addr_t *addr) {
 	if (!neigh) {
 		neigh = calloc(1, sizeof(ffd_neigh_t));
 		neigh->next = iface->neigh_list;
+		neigh->iface = iface;
 		iface->neigh_list = neigh;
 		neigh->addr = *addr;
 
@@ -41,16 +42,21 @@ ffd_neigh_t* ffd_neigh_get(ffd_iface_t *iface, const eth_addr_t *addr) {
 	return neigh;
 }
 
-void ffd_neigh_free_list(ffd_neigh_t *neigh) {
+void ffd_neigh_unref_list(ffd_neigh_t *neigh) {
 	ffd_neigh_t *next;
 	for (; neigh; neigh = next) {
 		next = neigh->next;
-		free(neigh);
+
+		neigh->iface = NULL;
+		neigh->next = NULL;
+
+		if (!neigh->ref)
+			free(neigh);
 	}
 }
 
 uint16_t ffd_neigh_get_rxcost(const ffd_neigh_t *neigh) {
-	if (!neigh->hello_log || !neigh->hello_interval)
+	if (!neigh->hello_log || !neigh->hello_interval || !neigh->iface)
 		return 0xffff;
 
 	int timediff = timespec_diff(&now, &neigh->last_hello);
@@ -68,7 +74,7 @@ uint16_t ffd_neigh_get_rxcost(const ffd_neigh_t *neigh) {
 }
 
 uint16_t ffd_neigh_get_txcost(const ffd_neigh_t *neigh) {
-	if (timespec_diff(&now, &neigh->last_ihu) > FFD_IHU_TIMEOUT(neigh->ihu_interval))
+	if (timespec_diff(&now, &neigh->last_ihu) > FFD_IHU_TIMEOUT(neigh->ihu_interval) || !neigh->iface)
 		return 0xffff;
 	else
 		return neigh->txcost;
diff --git a/ffd/neigh.h b/ffd/neigh.h
index d82025c..aa0d1f9 100644
--- a/ffd/neigh.h
+++ b/ffd/neigh.h
@@ -40,8 +40,18 @@ static inline ffd_neigh_t* ffd_neigh_find(const ffd_iface_t *iface, const eth_ad
 	return NULL;
 }
 
+static inline void ffd_neigh_ref(ffd_neigh_t *neigh) {
+	neigh->ref++;
+}
+
+static inline void ffd_neigh_unref(ffd_neigh_t *neigh) {
+	if (!(--neigh->ref) && !neigh->iface)
+		free(neigh);
+}
+
 ffd_neigh_t* ffd_neigh_get(ffd_iface_t *iface, const eth_addr_t *addr);
-void ffd_neigh_free_list(ffd_neigh_t *neigh);
+void ffd_neigh_unref(ffd_neigh_t *neigh);
+void ffd_neigh_unref_list(ffd_neigh_t *neigh);
 
 uint16_t ffd_neigh_get_rxcost(const ffd_neigh_t *neigh);
 uint16_t ffd_neigh_get_txcost(const ffd_neigh_t *neigh);