1 files changed, 57 insertions, 4 deletions

diff --git a/ffd/ffd.c b/ffd/ffd.c
index f82932a..5e967f3 100644
--- a/ffd/ffd.c
+++ b/ffd/ffd.c
@@ -336,8 +336,15 @@ static void handle_tlv_update(const ffd_tlv_update_t *tlv_update, size_t len, ha
 			nexthop = new_nexthop(announce, neigh);
 	}
 	else {
-		if (!feasible && nexthop == announce->selected)
+		if (!feasible && nexthop == announce->selected) {
+			ffd_send_seqno_request_for(neigh, announce);
 			nexthop = NULL;
+		}
+	}
+
+	if (!feasible && nexthop && nexthop != announce->selected) {
+		if (ms.metric + ffd_neigh_get_cost(neigh) < announce->metric.metric)
+			ffd_send_seqno_request_for(neigh, announce);
 	}
 
 	if ((tlv_update->flags & FFD_UPDATE_WITH_DATA) && !announce->data) {
@@ -369,6 +376,8 @@ static void handle_tlv_announce_req(const ffd_tlv_announce_req_t *tlv_req, size_
 		return;
 	}
 
+	fprintf(stderr, "debug: received announce request\n");
+
 	if (ffd_is_node_id_unspec(&tlv_req->node)) {
 		ffd_send_update(NULL, get_tlv_neigh(arg), NULL, tlv_req->flags & FFD_UPDATE_WITH_DATA);
 	}
@@ -382,6 +391,48 @@ static void handle_tlv_announce_req(const ffd_tlv_announce_req_t *tlv_req, size_
 	}
 }
 
+static void handle_tlv_seqno_req(const ffd_tlv_seqno_req_t *tlv_req, size_t len, handle_tlv_arg_t *arg) {
+	if (len < sizeof(ffd_tlv_seqno_req_t)) {
+		fprintf(stderr, "warn: received short seqno request TLV.\n");
+		return;
+	}
+
+	fprintf(stderr, "debug: received seqno request\n");
+
+	ffd_announce_t *announce = ffd_announce_find(&tlv_req->node, ntohs(tlv_req->type), ntohs(tlv_req->key));
+
+	if (!announce) {
+		fprintf(stderr, "debug: received seqno request for unknown announce\n");
+		return;
+	}
+
+	if (!announce->selected) {
+		fprintf(stderr, "debug: received seqno request for starved announce\n");
+		return;
+	}
+
+	ffd_neigh_t *neigh = get_tlv_neigh(arg);
+
+	if (announce->selected->neigh == neigh)
+		return;
+
+	if ((int16_t)(ntohs(tlv_req->seqno)-announce->selected->metric_seqno.seqno) <= 0) {
+		fprintf(stderr, "debug: received seqno request, seqno already ok\n");
+		ffd_send_update(NULL, neigh, announce, false);
+		return;
+	}
+
+	if (!announce->selected->neigh) {
+		fprintf(stderr, "debug: incrementing seqno\n");
+		announce->selected->metric_seqno.seqno++;
+		ffd_send_update(NULL, neigh, announce, false);
+		return;
+	}
+
+	fprintf(stderr, "debug: received seqno request, forwarding\n");
+	ffd_send_seqno_request(announce->selected->neigh, announce, ntohs(tlv_req->seqno));
+}
+
 static void handle_tlv(ffd_tlv_type_t type, const void *data, size_t len, void *arg) {
 	switch (type) {
 	case TLV_ACK_REQ:
@@ -412,6 +463,10 @@ static void handle_tlv(ffd_tlv_type_t type, const void *data, size_t len, void *
 		handle_tlv_announce_req(data, len, arg);
 		return;
 
+	case TLV_SEQNO_REQ:
+		handle_tlv_seqno_req(data, len, arg);
+		return;
+
 	default:
 		fprintf(stderr, "debug: received unknown TLV %u on %s.\n", type, ((handle_tlv_arg_t*)arg)->iface->name);
 		return;
@@ -442,10 +497,8 @@ static void receive_packet(void) {
 
 	handle_tlv_arg_t arg = { .iface = get_iface(from.sll_ifindex), .addr = (const eth_addr_t*)&from.sll_addr };
 
-	if (!arg.iface) {
-		fprintf(stderr, "debug: received packet on unknown interface.\n");
+	if (!arg.iface)
 		return;
-	}
 
 	if (!ffd_tlv_parse(packet, handle_tlv, &arg)) {
 		fprintf(stderr, "debug: received invalid packet.\n");