Calculate rxcost

2 files changed, 17 insertions, 7 deletions

diff --git a/ffd/ffd.c b/ffd/ffd.c
index 1fc9eed..14d770c 100644
--- a/ffd/ffd.c
+++ b/ffd/ffd.c
@@ -167,15 +167,12 @@ static inline ffd_neigh_t* get_neigh(const ffd_iface_t *iface, const eth_addr_t
 static ffd_neigh_t* get_neigh_create(ffd_iface_t *iface, const eth_addr_t *addr) {
 	ffd_neigh_t *neigh = get_neigh(iface, addr);
 	if (!neigh) {
-		neigh = malloc(sizeof(ffd_neigh_t));
+		neigh = calloc(1, sizeof(ffd_neigh_t));
 		neigh->next = iface->neigh_list;
 		iface->neigh_list = neigh;
-
 		neigh->addr = *addr;
-		neigh->hello_log = 0;
-		neigh->hello_interval = 0;
-		neigh->last_seqno = 0;
-		neigh->last_hello = (struct timespec){};
+
+		neigh->txcost = 0xffff;
 	}
 
 	return neigh;
@@ -189,6 +186,17 @@ static void free_neighs(ffd_neigh_t *neigh) {
 	}
 }
 
+static uint16_t neigh_get_rxcost(ffd_neigh_t *neigh) {
+	int timediff = timespec_diff(&now, &neigh->last_hello)/10;
+	int shift = (timediff - neigh->hello_interval/2)/neigh->hello_interval;
+	int received = __builtin_popcount(neigh->hello_log << shift);
+
+	if (received == 0)
+		return 0xffff;
+	else
+		return (0x1000/received);
+}
+
 static void update_netifs() {
 	ffd_iface_t *iface, **cur;
 
@@ -308,7 +316,7 @@ static void handle_tlv_hello(const ffd_tlv_hello_t *tlv_hello, size_t len, const
 	neigh->last_seqno = seqno;
 	neigh->last_hello = now;
 
-	fprintf(stderr, "debug: accepted hello, log %04x.\n", neigh->hello_log);
+	fprintf(stderr, "debug: accepted hello, log %04x, rxcost is %u now.\n", neigh->hello_log, neigh_get_rxcost(neigh));
 }
 
 static void handle_tlv(ffd_tlv_type_t type, const void *data, size_t len, void *arg) {
diff --git a/ffd/ffd.h b/ffd/ffd.h
index e29fce6..1ef5494 100644
--- a/ffd/ffd.h
+++ b/ffd/ffd.h
@@ -50,6 +50,8 @@ typedef struct _ffd_neigh_t {
 	uint16_t hello_interval;
 	uint16_t last_seqno;
 	struct timespec last_hello;
+
+	uint16_t txcost;
 } ffd_neigh_t;
 
 typedef struct _ffd_iface_t {