--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sat/plugins/plugin_xep_0320.py	Mon May 15 17:02:40 2023 +0200
@@ -0,0 +1,106 @@
+#!/usr/bin/env python3
+
+
+# Libervia plugin
+# Copyright (C) 2009-2023 Jérôme Poisson (goffi@goffi.org)
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from twisted.words.protocols.jabber.xmlstream import XMPPHandler
+from twisted.words.xish import domish
+from wokkel import disco, iwokkel
+from zope.interface import implementer
+
+from sat.core.constants import Const as C
+from sat.core.i18n import _
+from sat.core.log import getLogger
+
+
+log = getLogger(__name__)
+
+NS_JINGLE_DTLS = "urn:xmpp:jingle:apps:dtls:0"
+
+PLUGIN_INFO = {
+    C.PI_NAME: "Use of DTLS-SRTP in Jingle Sessions",
+    C.PI_IMPORT_NAME: "XEP-0320",
+    C.PI_TYPE: "XEP",
+    C.PI_MODES: C.PLUG_MODE_BOTH,
+    C.PI_PROTOCOLS: ["XEP-0320"],
+    C.PI_DEPENDENCIES: ["XEP-0176"],
+    C.PI_RECOMMENDATIONS: [],
+    C.PI_MAIN: "XEP_0320",
+    C.PI_HANDLER: "yes",
+    C.PI_DESCRIPTION: _("""Use of DTLS-SRTP with RTP (for e2ee of A/V calls)"""),
+}
+
+
+class XEP_0320:
+    def __init__(self, host):
+        log.info(f"plugin {PLUGIN_INFO[C.PI_NAME]!r} initialization")
+        host.trigger.add("XEP-0176_parse_transport", self._parse_transport_trigger)
+        host.trigger.add("XEP-0176_build_transport", self._build_transport_trigger)
+
+    def get_handler(self, client):
+        return XEP_0320_handler()
+
+    def _parse_transport_trigger(
+        self, transport_elt: domish.Element, ice_data: dict
+    ) -> bool:
+        """Parse the <fingerprint> element"""
+        fingerprint_elt = next(
+            transport_elt.elements(NS_JINGLE_DTLS, "fingerprint"), None
+        )
+        if fingerprint_elt is not None:
+            try:
+                ice_data["fingerprint"] = {
+                    "hash": fingerprint_elt["hash"],
+                    "setup": fingerprint_elt["setup"],
+                    "fingerprint": str(fingerprint_elt),
+                }
+            except KeyError as e:
+                log.warning(
+                    f"invalid <fingerprint> (attribue {e} is missing): "
+                    f"{fingerprint_elt.toXml()})"
+                )
+
+        return True
+
+    def _build_transport_trigger(
+        self, tranport_elt: domish.Element, ice_data: dict
+    ) -> bool:
+        """Build the <fingerprint> element if possible"""
+        try:
+            fingerprint_data = ice_data["fingerprint"]
+            hash_ = fingerprint_data["hash"]
+            setup = fingerprint_data["setup"]
+            fingerprint = fingerprint_data["fingerprint"]
+        except KeyError:
+            pass
+        else:
+            fingerprint_elt = tranport_elt.addElement(
+                (NS_JINGLE_DTLS, "fingerprint"), content=fingerprint
+            )
+            fingerprint_elt["hash"] = hash_
+            fingerprint_elt["setup"] = setup
+
+        return True
+
+
+@implementer(iwokkel.IDisco)
+class XEP_0320_handler(XMPPHandler):
+    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
+        return [disco.DiscoFeature(NS_JINGLE_DTLS)]
+
+    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
+        return []