From 8cc0a4519f80647c315843091ac1705c0dc8d440 Mon Sep 17 00:00:00 2001
From: Nikola Dancejic <26731235+Ndancejic@users.noreply.github.com>
Date: Tue, 30 Aug 2022 09:15:26 -0700
Subject: [PATCH] [neighsyncd] Enabling ipv4 link local entries for non-dualtor
 (#2427)

* [neighsyncd] Enabling ipv4 link local entries for non-dualtor
Allow ipv4 link local entries to be programmed to the hardware unless on
a dual-tor setup.
---
 neighsyncd/neighsync.cpp | 12 ++++----
 tests/test_neighbor.py   | 63 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 6 deletions(-)

diff --git a/neighsyncd/neighsync.cpp b/neighsyncd/neighsync.cpp
index 8864746cb563..8f208e73fedd 100644
--- a/neighsyncd/neighsync.cpp
+++ b/neighsyncd/neighsync.cpp
@@ -63,6 +63,9 @@ void NeighSync::onMsg(int nlmsg_type, struct nl_object *obj)
     string key;
     string family;
     string intfName;
+    std::vector<std::string> peerSwitchKeys;
+    m_cfgPeerSwitchTable.getKeys(peerSwitchKeys);
+    bool is_dualtor = peerSwitchKeys.size() > 0;
 
     if ((nlmsg_type != RTM_NEWNEIGH) && (nlmsg_type != RTM_GETNEIGH) &&
         (nlmsg_type != RTM_DELNEIGH))
@@ -81,11 +84,11 @@ void NeighSync::onMsg(int nlmsg_type, struct nl_object *obj)
 
     nl_addr2str(rtnl_neigh_get_dst(neigh), ipStr, MAX_ADDR_SIZE);
 
-    /* Ignore IPv4 link-local addresses as neighbors */
+    /* Ignore IPv4 link-local addresses as neighbors if subtype is dualtor */
     IpAddress ipAddress(ipStr);
-    if (family == IPV4_NAME && ipAddress.getAddrScope() == IpAddress::AddrScope::LINK_SCOPE)
+    if (family == IPV4_NAME && ipAddress.getAddrScope() == IpAddress::AddrScope::LINK_SCOPE && is_dualtor)
     {
-        SWSS_LOG_INFO("Link Local address received, ignoring for %s", ipStr);
+        SWSS_LOG_INFO("Link Local address received on dualtor, ignoring for %s", ipStr);
         return;
     }
 
@@ -109,11 +112,8 @@ void NeighSync::onMsg(int nlmsg_type, struct nl_object *obj)
         return;
     }
 
-    std::vector<std::string> peerSwitchKeys;
     bool delete_key = false;
     bool use_zero_mac = false;
-    m_cfgPeerSwitchTable.getKeys(peerSwitchKeys);
-    bool is_dualtor = peerSwitchKeys.size() > 0;
     if (is_dualtor && (state == NUD_INCOMPLETE || state == NUD_FAILED))
     {
         SWSS_LOG_INFO("Unable to resolve %s, setting zero MAC", key.c_str());
diff --git a/tests/test_neighbor.py b/tests/test_neighbor.py
index 741ce9a71a9d..59618c75ce43 100644
--- a/tests/test_neighbor.py
+++ b/tests/test_neighbor.py
@@ -6,6 +6,14 @@
 
 
 class TestNeighbor(object):
+    CONFIG_PEER_SWITCH          = "PEER_SWITCH"
+    PEER_SWITCH_HOST            = "peer_switch_hostname"
+    PEER_IPV4                   = "10.1.0.33"
+
+    DEFAULT_PEER_SWITCH_PARAMS = {
+        "address_ipv4": PEER_IPV4
+    }
+
     def setup_db(self, dvs):
         self.pdb = swsscommon.DBConnector(0, dvs.redis_sock, 0)
         self.adb = swsscommon.DBConnector(1, dvs.redis_sock, 0)
@@ -428,6 +436,53 @@ def test_Ipv4LinkLocalNeighbor(self, dvs, testlog):
         # add neighbor
         self.add_neighbor("Ethernet8", "169.254.0.0", "00:01:02:03:04:05")
 
+        # check application database
+        tbl = swsscommon.Table(self.pdb, "NEIGH_TABLE:Ethernet8")
+        intf_entries = tbl.getKeys()
+        assert len(intf_entries) == 1
+
+        # check ASIC neighbor database
+        tbl = swsscommon.Table(self.adb, "ASIC_STATE:SAI_OBJECT_TYPE_NEIGHBOR_ENTRY")
+        intf_entries = tbl.getKeys()
+        assert len(intf_entries) == 1
+
+        # remove neighbor
+        self.remove_neighbor("Ethernet8", "169.254.0.0")
+
+        # remove IP from interface
+        self.remove_ip_address("Ethernet8", "10.0.0.1/24")
+
+        # remove interface
+        self.remove_l3_intf("Ethernet8")
+
+        # bring down interface
+        self.set_admin_status("Ethernet8", "down")
+
+        # check application database
+        tbl = swsscommon.Table(self.pdb, "NEIGH_TABLE:Ethernet8")
+        intf_entries = tbl.getKeys()
+        assert len(intf_entries) == 0
+
+        # check ASIC neighbor database
+        tbl = swsscommon.Table(self.adb, "ASIC_STATE:SAI_OBJECT_TYPE_NEIGHBOR_ENTRY")
+        intf_entries = tbl.getKeys()
+        assert len(intf_entries) == 0
+
+    def test_Ipv4LinkLocalNeighborWithDualToR(self, dvs, testlog, setup_peer_switch):
+        self.setup_db(dvs)
+
+        # bring up interface
+        self.set_admin_status("Ethernet8", "up")
+
+        # create interface
+        self.create_l3_intf("Ethernet8", "")
+
+        # assign IP to interface
+        self.add_ip_address("Ethernet8", "10.0.0.1/24")
+
+        # add neighbor
+        self.add_neighbor("Ethernet8", "169.254.0.0", "00:01:02:03:04:05")
+
         # check application database
         tbl = swsscommon.Table(self.pdb, "NEIGH_TABLE:Ethernet8")
         intf_entries = tbl.getKeys()
@@ -460,6 +515,14 @@ def test_Ipv4LinkLocalNeighbor(self, dvs, testlog):
         intf_entries = tbl.getKeys()
         assert len(intf_entries) == 0
 
+    @pytest.fixture
+    def setup_peer_switch(self, dvs):
+        config_db = dvs.get_config_db()
+        config_db.create_entry(
+            self.CONFIG_PEER_SWITCH,
+            self.PEER_SWITCH_HOST,
+            self.DEFAULT_PEER_SWITCH_PARAMS
+        )
 
 # Add Dummy always-pass test at end as workaroud
 # for issue when Flaky fail on final test it invokes module tear-down before retrying