lldp: add sd_lldp_tlv_packet_get_destination_type()

It can be useful to know the destination address of a LLDP frame
because it determines the scope of propagation of the frame and thus
this information be used to know whether the neighbor is connected to
the same physical link.

See clause 7.1 of IEEE Std 802.1AB-2009.

1 files changed, 11 insertions, 0 deletions

diff --git a/src/libsystemd-network/test-lldp.c b/src/libsystemd-network/test-lldp.c
index 26f64347a7..294198a0b5 100644
--- a/src/libsystemd-network/test-lldp.c
+++ b/src/libsystemd-network/test-lldp.c
@@ -202,6 +202,15 @@ static int lldp_parse_ttl_tlv(tlv_packet *m) {
         return 0;
 }
 
+static int lldp_get_destination_type(tlv_packet *m) {
+        int dest;
+
+        assert_se(sd_lldp_packet_get_destination_type(m, &dest) >= 0);
+        assert_se(dest == SD_LLDP_DESTINATION_TYPE_NEAREST_BRIDGE);
+
+        return 0;
+}
+
 static int lldp_parse_tlv_packet(tlv_packet *m, int len) {
         uint8_t subtype;
 
@@ -212,6 +221,8 @@ static int lldp_parse_tlv_packet(tlv_packet *m, int len) {
         assert_se(lldp_parse_ttl_tlv(m) >= 0);
         assert_se(lldp_parse_system_desc_tlv(m) >= 0);
 
+        assert_se(lldp_get_destination_type(m) >= 0);
+
         return 0;
 }