Implement PING, user to user only (XMPP and IRC side, using CTCP PING)

ref #2757

src/xmpp/xmpp_component.cpp

@@ -555,6 +555,16 @@ void XmppComponent::handle_iq(const Stanza& stanza)
               stanza_error.disable();
             }
         }
+      else if ((query = stanza.get_child("ping", PING_NS)))
+        {
+          Iid iid(to.local);
+          if (iid.is_user)
+            { // Ping any user (no check on the nick done ourself)
+              bridge->send_irc_user_ping_request(iid.get_server(),
+                                                 iid.get_local(), id, from, to_str);
+            }
+          stanza_error.disable();
+        }
     }
   else if (type == "result")
     {
@@ -1080,6 +1090,36 @@ void XmppComponent::send_iq_version_request(const std::string& from,
   this->send_stanza(iq);
 }
 
+void XmppComponent::send_ping_request(const std::string& from,
+                                      const std::string& jid_to,
+                                      const std::string& id)
+{
+  Stanza iq("iq");
+  iq["type"] = "get";
+  iq["id"] = id;
+  iq["from"] = from + "@" + this->served_hostname;
+  iq["to"] = jid_to;
+  XmlNode ping("ping");
+  ping["xmlns"] = PING_NS;
+  ping.close();
+  iq.add_child(std::move(ping));
+  iq.close();
+  this->send_stanza(iq);
+
+  auto result_cb = [from, id](Bridge* bridge, const Stanza& stanza)
+    {
+      Jid to(stanza.get_tag("to"));
+      if (to.local != from)
+        {
+          log_error("Received a corresponding ping result, but the 'to' from "
+                    "the response mismatches the 'from' of the request");
+        }
+      else
+        bridge->send_irc_ping_result(from, id);
+    };
+  this->waiting_iq[id] = result_cb;
+}
+
 void XmppComponent::send_iq_result(const std::string& id, const std::string& to_jid, const std::string& from_local_part)
 {
   Stanza iq("iq");

src/xmpp/xmpp_component.hpp

@@ -24,6 +24,8 @@
 #define STREAMS_NS       "urn:ietf:params:xml:ns:xmpp-streams"
 #define VERSION_NS       "jabber:iq:version"
 #define ADHOC_NS         "http://jabber.org/protocol/commands"
+#define PING_NS          "urn:xmpp:ping"
+
 /**
  * A callback called when the waited iq result is received (it is matched
  * against the iq id)
@@ -216,6 +218,12 @@ public:
    */
   void send_iq_version_request(const std::string& from,
                                const std::string& jid_to);
+  /**
+   * Send a ping request
+   */
+  void send_ping_request(const std::string& from,
+                         const std::string& jid_to,
+                         const std::string& id);
   /**
    * Send an empty iq of type result
    */