add netstat example

bindings/ruby/examples/netstat.rb

@@ -0,0 +1,54 @@
+require 'rbsigar'
+require 'socket'
+
+#XXX this example is incomplete wrt:
+#../../java/src/org/hyperic/sigar/cmd/Netstat.java
+
+is_numeric = false
+flags = Sigar::NETCONN_CLIENT|Sigar::NETCONN_SERVER
+flags |= Sigar::NETCONN_TCP
+
+def format_port(sigar, proto, port, is_numeric)
+  if port == 0
+    return "*"
+  end
+  if !is_numeric
+    service = sigar.net_services_name(proto, port)
+    if service != false
+      return service
+    end
+  end
+  port.to_s
+end
+
+def format_address(sigar, proto, ip, portnum, is_numeric)
+  port = format_port(sigar, proto, portnum, is_numeric)
+  address = ""
+  if ip == "0.0.0.0" || ip == "::"
+    address = "*"
+  elsif is_numeric
+    address = ip.to_s
+  else
+    begin
+      name = Socket.gethostbyname(ip)
+      address = name[0]
+    rescue SocketError
+      address = ip.to_s
+    end
+  end
+  return address + ":" + port
+end
+
+sigar = Sigar.new
+
+connections = sigar.net_connection_list(flags)
+puts "Proto\tLocal Address\tForeign Address\tState"
+
+connections.each do |conn|
+  proto = Sigar.net_connection_type_to_s(conn.type)
+  state = Sigar.net_connection_state_to_s(conn.state)
+  local = format_address(sigar, conn.type, conn.local_address, conn.local_port, is_numeric)
+  remote = format_address(sigar, conn.type, conn.remote_address, conn.remote_port, is_numeric)
+  puts proto + "\t" + local + "\t" + remote + "\t" + state
+end
+