Support setting med in routing policy action

Add support for updating the MED in routing policy action.
Test case to validate it

Change-Id: I23ac0570673329a571c48606e3fc80cdf057081a
Related-bug: #1500698

src/bgp/bgp_config.cc

@@ -369,6 +369,9 @@ string RoutingPolicyActionConfig::ToString() const {
     if (update.local_pref) {
         oss << "    local-preference " << update.local_pref << std::endl;
     }
+    if (update.med) {
+        oss << "    med " << update.med << std::endl;
+    }
 
     if (action == ACCEPT) {
         oss << "    accept" << std::endl;

src/bgp/bgp_config.h

@@ -317,6 +317,7 @@ struct ActionUpdate {
     CommunityList community_add;
     CommunityList community_remove;
     uint32_t local_pref;
+    uint32_t med;
 };
 
 struct RoutingPolicyActionConfig {

src/bgp/bgp_config_ifmap.cc

@@ -1592,6 +1592,7 @@ static void BuildPolicyTerm(autogen::PolicyTerm cfg_term,
         term->action.update.community_set.push_back(community);
     }
     term->action.update.local_pref = cfg_term.then.update.local_pref;
+    term->action.update.med = cfg_term.then.update.med;
     term->action.action = RoutingPolicyActionConfig::NEXT_TERM;
     if (strcmp(cfg_term.then.action.c_str(), "reject") == 0) {
         term->action.action = RoutingPolicyActionConfig::REJECT;

src/bgp/routing-policy/routing_policy.cc

@@ -423,6 +423,12 @@ RoutingPolicy::PolicyTermPtr RoutingPolicy::BuildTerm(const RoutingPolicyTerm &c
         actions.push_back(local_pref);
     }
 
+    if (cfg_term.action.update.med) {
+        UpdateMed *med =
+            new UpdateMed(cfg_term.action.update.med);
+        actions.push_back(med);
+    }
+
     PolicyTermPtr ret_term;
     if (!actions.empty() || !matches.empty()) {
         ret_term = PolicyTermPtr(new PolicyTerm());

src/bgp/routing-policy/routing_policy_action.cc

@@ -99,3 +99,23 @@ bool UpdateLocalPref::IsEqual(const RoutingPolicyAction &local_pref) const {
         static_cast<const UpdateLocalPref&>(local_pref);
     return (local_pref_ == in_lp.local_pref_);
 }
+
+UpdateMed::UpdateMed(uint32_t med)
+    : med_(med) {
+}
+
+void UpdateMed::operator()(BgpAttr *attr) const {
+    attr->set_med(med_);
+}
+
+string UpdateMed::ToString() const {
+    ostringstream oss;
+    oss << "med " << med_;
+    return oss.str();
+}
+
+bool UpdateMed::IsEqual(const RoutingPolicyAction &med) const {
+    const UpdateMed in_med =
+        static_cast<const UpdateMed&>(med);
+    return (med_ == in_med.med_);
+}

src/bgp/routing-policy/routing_policy_action.h

@@ -105,4 +105,16 @@ class UpdateLocalPref : public RoutingPolicyUpdateAction {
 private:
     uint32_t local_pref_;
 };
+
+class UpdateMed : public RoutingPolicyUpdateAction {
+public:
+    UpdateMed(uint32_t med);
+    virtual ~UpdateMed() {}
+    virtual void operator()(BgpAttr *out_attr) const;
+    std::string ToString() const;
+    virtual bool IsEqual(const RoutingPolicyAction &med) const;
+private:
+    uint32_t med_;
+};
+
 #endif // SRC_BGP_ROUTING_POLICY_ROUTING_POLICY_ACTION_H_

src/bgp/test/routing_policy_test.cc

@@ -390,6 +390,36 @@ TEST_F(RoutingPolicyTest, PolicyMultiplePrefixMatchUpdateLocalPref) {
 }
 
 
+TEST_F(RoutingPolicyTest, PolicyNoMatchUpdateMed) {
+    string content =
+        FileRead("controller/src/bgp/testdata/routing_policy_1b.xml");
+    EXPECT_TRUE(parser_.Parse(content));
+    task_util::WaitForIdle();
+
+    boost::system::error_code ec;
+    peers_.push_back(
+        new BgpPeerMock(Ip4Address::from_string("192.168.0.1", ec)));
+
+    AddRoute<InetDefinition>(peers_[0], "test.inet.0",
+                                   "10.0.1.1/32", 100);
+    task_util::WaitForIdle();
+
+    VERIFY_EQ(1, RouteCount("test.inet.0"));
+    BgpRoute *rt =
+        RouteLookup<InetDefinition>("test.inet.0", "10.0.1.1/32");
+    ASSERT_TRUE(rt != NULL);
+    VERIFY_EQ(peers_[0], rt->BestPath()->GetPeer());
+    const BgpAttr *attr = rt->BestPath()->GetAttr();
+    const BgpAttr *orig_attr = rt->BestPath()->GetOriginalAttr();
+    uint32_t original_med = orig_attr->med();
+    uint32_t policy_med = attr->med();
+    ASSERT_TRUE(policy_med == 1234);
+    ASSERT_TRUE(original_med == 0);
+
+    DeleteRoute<InetDefinition>(peers_[0], "test.inet.0", "10.0.1.1/32");
+}
+
+
 TEST_F(RoutingPolicyTest, PolicyCommunityMatchReject) {
     string content =
         FileRead("controller/src/bgp/testdata/routing_policy_0.xml");

src/bgp/testdata/routing_policy_1b.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<config>
+    <routing-policy name='basic'>
+        <term>
+            <then>
+                <update>
+                    <med>1234</med>
+                </update>
+            </then>
+        </term>
+    </routing-policy>
+    <routing-instance name="test">
+        <routing-policy to="basic">
+            <sequence>1.0</sequence>
+        </routing-policy>
+        <vrf-target>target:1:103</vrf-target>
+    </routing-instance>
+</config>

src/schema/routing_policy.xsd

@@ -35,6 +35,7 @@
 <xsd:complexType name="ActionUpdate">
     <xsd:element name="community"   type="ActionCommunity"/>
     <xsd:element name="local-pref"  type="xsd:integer"/>
+    <xsd:element name="med"         type="xsd:integer"/>
 </xsd:complexType>
 
 <xsd:complexType name='PolicyAction'>