snitch, code: Make get_datacenter() report local dc only

The continuation of the previous patch -- all the code uses
topology::get_datacenter(endpoint) to get peers' dc string. The topology
still uses snitch for that, but it already contains the needed data.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>

locator/production_snitch_base.cc

@@ -37,14 +37,8 @@ sstring production_snitch_base::get_rack() {
     return _my_rack;
 }
 
-sstring production_snitch_base::get_datacenter(inet_address endpoint) {
-    if (endpoint == utils::fb_utilities::get_broadcast_address()) {
-        return _my_dc;
-    }
-
-    return get_endpoint_info(endpoint,
-                             gms::application_state::DC,
-                             default_dc);
+sstring production_snitch_base::get_datacenter() {
+    return _my_dc;
 }
 
 void production_snitch_base::set_backreference(snitch_ptr& d) {

locator/production_snitch_base.hh

@@ -43,7 +43,7 @@ public:
     explicit production_snitch_base(snitch_config);
 
     virtual sstring get_rack() override;
-    virtual sstring get_datacenter(inet_address endpoint) override;
+    virtual sstring get_datacenter() override;
     virtual void set_backreference(snitch_ptr& d) override;
 
 private:

locator/rack_inferring_snitch.hh

@@ -25,7 +25,7 @@ using inet_address = gms::inet_address;
  */
 struct rack_inferring_snitch : public snitch_base {
     rack_inferring_snitch(const snitch_config& cfg) {
-        _my_dc = get_datacenter(utils::fb_utilities::get_broadcast_address());
+        _my_dc = get_datacenter();
         _my_rack = get_rack();
 
         // This snitch is ready on creation
@@ -37,7 +37,8 @@ struct rack_inferring_snitch : public snitch_base {
         return std::to_string(uint8_t(endpoint.bytes()[2]));
     }
 
-    virtual sstring get_datacenter(inet_address endpoint) override {
+    virtual sstring get_datacenter() override {
+        auto endpoint = utils::fb_utilities::get_broadcast_address();
         return std::to_string(uint8_t(endpoint.bytes()[1]));
     }
 

locator/simple_snitch.hh

@@ -22,7 +22,7 @@ namespace locator {
  */
 struct simple_snitch : public snitch_base {
     simple_snitch(const snitch_config& cfg) {
-        _my_dc = get_datacenter(utils::fb_utilities::get_broadcast_address());
+        _my_dc = get_datacenter();
         _my_rack = get_rack();
 
         // This snitch is ready on creation
@@ -33,7 +33,7 @@ struct simple_snitch : public snitch_base {
         return "rack1";
     }
 
-    virtual sstring get_datacenter(inet_address endpoint) override {
+    virtual sstring get_datacenter() override {
         return "datacenter1";
     }
 

locator/snitch_base.hh

@@ -66,9 +66,9 @@ public:
     virtual sstring get_rack() = 0;
 
     /**
-     * returns a String representing the datacenter this endpoint belongs to
+     * returns a String representing the datacenter local node belongs to
      */
-    virtual sstring get_datacenter(inet_address endpoint) = 0;
+    virtual sstring get_datacenter() = 0;
 
     /**
      * returns whatever info snitch wants to gossip
@@ -299,7 +299,7 @@ public:
     //
     // Sons have to implement:
     // virtual sstring get_rack()        = 0;
-    // virtual sstring get_datacenter(inet_address endpoint)  = 0;
+    // virtual sstring get_datacenter()  = 0;
     //
 
     virtual std::list<std::pair<gms::application_state, gms::versioned_value>> get_app_states() const override;

locator/token_metadata.cc

@@ -1351,7 +1351,7 @@ sstring topology::get_datacenter() const {
 }
 
 sstring topology::get_datacenter(inet_address ep) const {
-    return i_endpoint_snitch::get_local_snitch_ptr()->get_datacenter(ep);
+    return get_location(ep).dc;
 }
 
 void topology::sort_by_proximity(inet_address address, inet_address_vector_replica_set& addresses) const {