Don't forward frames with local destination MAC address

3 files changed, 23 insertions, 11 deletions

diff --git a/src/peer.c b/src/peer.c
index 03e5716..7a05dbd 100644
--- a/src/peer.c
+++ b/src/peer.c
@@ -862,7 +862,7 @@ static int peer_eth_addr_cmp(const fastd_peer_eth_addr_t *addr1, const fastd_pee
 void fastd_peer_eth_addr_add(fastd_peer_t *peer, fastd_eth_addr_t addr) {
 	int min = 0, max = VECTOR_LEN(ctx.eth_addrs);
 
-	if (!fastd_peer_is_established(peer))
+	if (peer && !fastd_peer_is_established(peer))
 		exit_bug("tried to learn ethernet address on non-established peer");
 
 	while (max > min) {
@@ -884,18 +884,22 @@ void fastd_peer_eth_addr_add(fastd_peer_t *peer, fastd_eth_addr_t addr) {
 
 	VECTOR_INSERT(ctx.eth_addrs, ((fastd_peer_eth_addr_t) {addr, peer, ctx.now + ETH_ADDR_STALE_TIME}), min);
 
-	pr_debug("learned new MAC address %E on peer %P", &addr, peer);
+	if (peer)
+		pr_debug("learned new MAC address %E on peer %P", &addr, peer);
+	else
+		pr_debug("learned new local MAC address %E", &addr);
 }
 
 /** Finds the peer that is associated with a given MAC address */
-fastd_peer_t * fastd_peer_find_by_eth_addr(const fastd_eth_addr_t addr) {
+bool fastd_peer_find_by_eth_addr(const fastd_eth_addr_t addr, fastd_peer_t **peer) {
 	const fastd_peer_eth_addr_t key = {.addr = addr};
 	fastd_peer_eth_addr_t *peer_eth_addr = VECTOR_BSEARCH(&key, ctx.eth_addrs, peer_eth_addr_cmp);
 
-	if (peer_eth_addr)
-		return peer_eth_addr->peer;
-	else
-		return NULL;
+	if (!peer_eth_addr)
+		return false;
+
+	*peer = peer_eth_addr->peer;
+	return true;
 }
 
 /**
diff --git a/src/peer.h b/src/peer.h
index 30c9156..ca03e2f 100644
--- a/src/peer.h
+++ b/src/peer.h
@@ -271,7 +271,7 @@ static inline bool fastd_eth_addr_is_unicast(fastd_eth_addr_t addr) {
 }
 
 void fastd_peer_eth_addr_add(fastd_peer_t *peer, fastd_eth_addr_t addr);
-fastd_peer_t * fastd_peer_find_by_eth_addr(fastd_eth_addr_t addr);
+bool fastd_peer_find_by_eth_addr(const fastd_eth_addr_t addr, fastd_peer_t **peer);
 
 void fastd_peer_handle_handshake_queue(void);
 void fastd_peer_maintenance(void);
diff --git a/src/send.c b/src/send.c
index 19f0649..8b9aae7 100644
--- a/src/send.c
+++ b/src/send.c
@@ -206,16 +206,24 @@ static inline bool send_data_tap_single(fastd_buffer_t buffer, fastd_peer_t *sou
 		return true;
 	}
 
+	if (!source) {
+		fastd_eth_addr_t src_addr = fastd_buffer_source_address(buffer);
+
+		if (fastd_eth_addr_is_unicast(src_addr))
+			fastd_peer_eth_addr_add(NULL, src_addr);
+	}
+
 	fastd_eth_addr_t dest_addr = fastd_buffer_dest_address(buffer);
 	if (!fastd_eth_addr_is_unicast(dest_addr))
 		return false;
 
-	fastd_peer_t *dest = fastd_peer_find_by_eth_addr(dest_addr);
+	fastd_peer_t *dest;
+	bool found = fastd_peer_find_by_eth_addr(dest_addr, &dest);
 
-	if (!dest)
+	if (!found)
 		return false;
 
-	if (dest == source) {
+	if (!dest || dest == source) {
 		fastd_buffer_free(buffer);
 		return true;
 	}