[intfmgr]: Enable accept_untracked_na kernel param (sonic-net#2436)

* [intfmgr]: Enable `accept_untracked_na` kernel param
* When enabling gratuitous ARP, also enable acceptance of untracked neighbor advertisements

cfgmgr/intfmgr.cpp

@@ -535,11 +535,12 @@ void IntfMgr::removeSubIntfState(const string &alias)
 bool IntfMgr::setIntfGratArp(const string &alias, const string &grat_arp)
 {
     /*
-     * Enable gratuitous ARP by accepting unsolicited ARP replies
+     * Enable gratuitous ARP by accepting unsolicited ARP replies and untracked neighbor advertisements
      */
     stringstream cmd;
     string res;
     string garp_enabled;
+    int rc;
 
     if (grat_arp == "enabled")
     {
@@ -557,8 +558,23 @@ bool IntfMgr::setIntfGratArp(const string &alias, const string &grat_arp)
 
     cmd << ECHO_CMD << " " << garp_enabled << " > /proc/sys/net/ipv4/conf/" << alias << "/arp_accept";
     EXEC_WITH_ERROR_THROW(cmd.str(), res);
-
     SWSS_LOG_INFO("ARP accept set to \"%s\" on interface \"%s\"",  grat_arp.c_str(), alias.c_str());
+
+    cmd.clear();
+    cmd.str(std::string());
+
+    // `accept_untracked_na` is not available in all kernels, so check for it before trying to set it
+    cmd << "test -f /proc/sys/net/ipv6/conf/" << alias << "/accept_untracked_na";
+    rc = swss::exec(cmd.str(), res);
+
+    if (rc == 0) {
+        cmd.clear();
+        cmd.str(std::string());
+        cmd << ECHO_CMD << " " << garp_enabled << " > /proc/sys/net/ipv6/conf/" << alias << "/accept_untracked_na";
+        EXEC_WITH_ERROR_THROW(cmd.str(), res);
+        SWSS_LOG_INFO("`accept_untracked_na` set to \"%s\" on interface \"%s\"",  grat_arp.c_str(), alias.c_str());
+    }
+
     return true;
 }
 

tests/dvslib/dvs_vlan.py

@@ -13,6 +13,17 @@ def create_vlan(self, vlanID):
         vlan_entry = {"vlanid": vlanID}
         self.config_db.create_entry("VLAN", vlan, vlan_entry)
 
+    def create_vlan_interface(self,  vlanID):
+        vlan = "Vlan{}".format(vlanID)
+        vlan_intf_entry = {}
+        self.config_db.create_entry("VLAN_INTERFACE", vlan, vlan_intf_entry)
+
+    def set_vlan_intf_property(self, vlanID, property, value):
+        vlan_key = "Vlan{}".format(vlanID)
+        vlan_entry = self.config_db.get_entry("VLAN_INTERFACE", vlan_key)
+        vlan_entry[property] = value
+        self.config_db.update_entry("VLAN_INTERFACE", vlan_key, vlan_entry)
+
     def create_vlan_hostif(self, vlan, hostif_name):
         vlan = "Vlan{}".format(vlan)
         vlan_entry = {"vlanid": vlan,  "host_ifname": hostif_name}

tests/test_vlan.py

@@ -2,7 +2,7 @@
 import pytest
 
 from distutils.version import StrictVersion
-from dvslib.dvs_common import PollingConfig
+from dvslib.dvs_common import PollingConfig, wait_for_result
 
 @pytest.mark.usefixtures("testlog")
 @pytest.mark.usefixtures('dvs_vlan_manager')
@@ -436,6 +436,58 @@ def test_VlanHostIf(self, dvs):
         self.dvs_vlan.get_and_verify_vlan_ids(0)
         self.dvs_vlan.get_and_verify_vlan_hostif_ids(len(dvs.asic_db.hostif_name_map) - 1)
 
+    def test_VlanGratArp(self, dvs):
+        def arp_accept_enabled():
+            rc, res = dvs.runcmd("cat /proc/sys/net/ipv4/conf/Vlan{}/arp_accept".format(vlan))
+            return (res.strip("\n") == "1", res)
+
+        def arp_accept_disabled():
+            rc, res = dvs.runcmd("cat /proc/sys/net/ipv4/conf/Vlan{}/arp_accept".format(vlan))
+            return (res.strip("\n") == "0", res)
+
+        vlan = "2"
+        self.dvs_vlan.create_vlan(vlan)
+        self.dvs_vlan.create_vlan_interface(vlan)
+        self.dvs_vlan.set_vlan_intf_property(vlan, "grat_arp", "enabled")
+
+        wait_for_result(arp_accept_enabled, PollingConfig(), "IPv4 arp_accept not enabled")
+
+        # Not currently possible to test `accept_untracked_na` as it doesn't exist in the kernel for
+        # our test VMs (only present in kernels 5.19 and above)
+
+        self.dvs_vlan.set_vlan_intf_property(vlan, "grat_arp", "disabled")
+
+        wait_for_result(arp_accept_disabled, PollingConfig(), "IPv4 arp_accept not disabled")
+
+        self.dvs_vlan.remove_vlan(vlan)
+
+    def test_VlanProxyArp(self, dvs): 
+
+        def proxy_arp_enabled():
+            rc, proxy_arp_res = dvs.runcmd("cat /proc/sys/net/ipv4/conf/Vlan{}/proxy_arp".format(vlan))
+            rc, pvlan_res = dvs.runcmd("cat /proc/sys/net/ipv4/conf/Vlan{}/proxy_arp_pvlan".format(vlan))
+
+            return (proxy_arp_res.strip("\n") == "1" and pvlan_res.strip("\n") == "1", (proxy_arp_res, pvlan_res))
+
+        def proxy_arp_disabled():
+            rc, proxy_arp_res = dvs.runcmd("cat /proc/sys/net/ipv4/conf/Vlan{}/proxy_arp".format(vlan))
+            rc, pvlan_res = dvs.runcmd("cat /proc/sys/net/ipv4/conf/Vlan{}/proxy_arp_pvlan".format(vlan))
+
+            return (proxy_arp_res.strip("\n") == "0" and pvlan_res.strip("\n") == "0", (proxy_arp_res, pvlan_res))
+
+        vlan = "2"
+        self.dvs_vlan.create_vlan(vlan)
+        self.dvs_vlan.create_vlan_interface(vlan)
+        self.dvs_vlan.set_vlan_intf_property(vlan, "proxy_arp", "enabled")
+
+        wait_for_result(proxy_arp_enabled, PollingConfig(), 'IPv4 proxy_arp or proxy_arp_pvlan not enabled')
+
+        self.dvs_vlan.set_vlan_intf_property(vlan, "proxy_arp", "disabled")
+
+        wait_for_result(proxy_arp_disabled, PollingConfig(), 'IPv4 proxy_arp or proxy_arp_pvlan not disabled')
+
+        self.dvs_vlan.remove_vlan(vlan)
+
 # Add Dummy always-pass test at end as workaroud
 # for issue when Flaky fail on final test it invokes module tear-down before retrying
 def test_nonflaky_dummy():