From 4fc6de5df31c81ae35e82ed91d0a2ee515edad41 Mon Sep 17 00:00:00 2001
From: Beniamino Galvani <bgalvani@redhat.com>
Date: Mon, 27 Jul 2015 18:04:46 +0200
Subject: [PATCH] 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.
---
 src/libsystemd-network/lldp-tlv.c  | 17 +++++++++++++++++
 src/libsystemd-network/lldp-tlv.h  |  4 ++++
 src/libsystemd-network/test-lldp.c | 11 +++++++++++
 src/systemd/sd-lldp.h              |  8 ++++++++
 4 files changed, 40 insertions(+)

diff --git a/src/libsystemd-network/lldp-tlv.c b/src/libsystemd-network/lldp-tlv.c
index 24f2606..996c5b8 100644
--- a/src/libsystemd-network/lldp-tlv.c
+++ b/src/libsystemd-network/lldp-tlv.c
@@ -539,3 +539,20 @@ int sd_lldp_packet_read_system_capability(tlv_packet *tlv, uint16_t *data) {
 
         return r;
 }
+
+int sd_lldp_packet_get_destination_type(tlv_packet *tlv, int *dest) {
+        assert_return(tlv, -EINVAL);
+        assert_return(dest, -EINVAL);
+
+        /* 802.1AB-2009, Table 7-1 */
+        if (!memcmp(&tlv->mac, LLDP_MAC_NEAREST_BRIDGE, ETH_ALEN))
+                *dest = SD_LLDP_DESTINATION_TYPE_NEAREST_BRIDGE;
+        else if (!memcmp(&tlv->mac, LLDP_MAC_NEAREST_NON_TPMR_BRIDGE, ETH_ALEN))
+                *dest = SD_LLDP_DESTINATION_TYPE_NEAREST_NON_TPMR_BRIDGE;
+        else if (!memcmp(&tlv->mac, LLDP_MAC_NEAREST_CUSTOMER_BRIDGE, ETH_ALEN))
+                *dest = SD_LLDP_DESTINATION_TYPE_NEAREST_CUSTOMER_BRIDGE;
+        else
+                return -EINVAL;
+
+        return 0;
+}
diff --git a/src/libsystemd-network/lldp-tlv.h b/src/libsystemd-network/lldp-tlv.h
index 19509d3..5af06b4 100644
--- a/src/libsystemd-network/lldp-tlv.h
+++ b/src/libsystemd-network/lldp-tlv.h
@@ -43,6 +43,10 @@ struct tlv_section {
         LIST_FIELDS(tlv_section, section);
 };
 
+#define LLDP_MAC_NEAREST_BRIDGE          (uint8_t[]) { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x0e }
+#define LLDP_MAC_NEAREST_NON_TPMR_BRIDGE (uint8_t[]) { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x03 }
+#define LLDP_MAC_NEAREST_CUSTOMER_BRIDGE (uint8_t[]) { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 }
+
 int tlv_section_new(tlv_section **ret);
 void tlv_section_free(tlv_section *ret);
 
diff --git a/src/libsystemd-network/test-lldp.c b/src/libsystemd-network/test-lldp.c
index 26f6434..294198a 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;
 }
 
diff --git a/src/systemd/sd-lldp.h b/src/systemd/sd-lldp.h
index e472cbe..bf6dfc1 100644
--- a/src/systemd/sd-lldp.h
+++ b/src/systemd/sd-lldp.h
@@ -28,6 +28,12 @@ enum {
         SD_LLDP_EVENT_UPDATE_INFO       = 0,
 };
 
+enum {
+        SD_LLDP_DESTINATION_TYPE_NEAREST_BRIDGE,
+        SD_LLDP_DESTINATION_TYPE_NEAREST_NON_TPMR_BRIDGE,
+        SD_LLDP_DESTINATION_TYPE_NEAREST_CUSTOMER_BRIDGE,
+};
+
 typedef struct sd_lldp sd_lldp;
 typedef struct tlv_packet sd_lldp_packet;
 
@@ -56,4 +62,6 @@ int sd_lldp_packet_read_port_description(sd_lldp_packet *tlv, char **data, uint1
 sd_lldp_packet *sd_lldp_packet_ref(sd_lldp_packet *tlv);
 sd_lldp_packet *sd_lldp_packet_unref(sd_lldp_packet *tlv);
 
+int sd_lldp_packet_get_destination_type(sd_lldp_packet *tlv, int *dest);
+
 int sd_lldp_get_packets(sd_lldp *lldp, sd_lldp_packet ***tlvs);
-- 
2.7.4