Add TCP support

config-example.toml

@@ -4,7 +4,6 @@ name = "velping"
 pings = 25
 
 [pinging]
-allow_empty_responses = false
 seconds_between_ping = 60
 
 [ntfy]
@@ -12,5 +11,16 @@ enabled = false
 server = "ntfy.sh"
 topic = "my_velping_instance"
 
-[services]
-Google = "https://google.com/"
+[services.google]
+name = "Google"
+type = "http"
+address = "https://google.com/"
+timeout = 5
+
+[services.iana-whois]
+name = "IANA WHOIS"
+type = "tcp"
+port = 43
+hostname = "whois.iana.org"
+timeout = 5
+ip_version = 4