Feat linux firewall support (#805)

Update the client's engine to apply firewall rules received from the manager (results of ACL policy).

management/proto/management.proto

@@ -186,6 +186,9 @@ message NetworkMap {
 
   // RemotePeerConfig represents a list of remote peers that the receiver can connect to
   repeated RemotePeerConfig offlinePeers = 7;
+
+  // FirewallRule represents a list of firewall rules to be applied to peer
+  repeated FirewallRule FirewallRules = 8;
 }
 
 // RemotePeerConfig represents a configuration of a remote peer.
@@ -297,4 +300,29 @@ message NameServer {
   string IP = 1;
   int64  NSType = 2;
   int64  Port = 3;
-}
+}
+
+// FirewallRule represents a firewall rule
+message FirewallRule {
+  string PeerIP = 1;
+  direction Direction = 2;
+  action Action = 3;
+  protocol Protocol = 4;
+  string Port = 5;
+
+  enum direction {
+    IN = 0;
+    OUT = 1;
+  }
+  enum action {
+    ACCEPT = 0;
+    DROP = 1;
+  }
+  enum protocol {
+    UNKNOWN = 0;
+    ALL = 1;
+    TCP = 2;
+    UDP = 3;
+    ICMP = 4;
+  }
+}