diff --git a/sat/plugins/plugin_xep_0294.py b/sat/plugins/plugin_xep_0294.py
new file mode 100644
index 00000000..03e1f289
--- /dev/null
+++ b/sat/plugins/plugin_xep_0294.py
@@ -0,0 +1,253 @@
+#!/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 .
+
+from typing import Dict, List, Optional, Union
+
+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 import exceptions
+from sat.core.constants import Const as C
+from sat.core.i18n import _
+from sat.core.log import getLogger
+
+log = getLogger(__name__)
+
+NS_JINGLE_RTP_HDREXT = "urn:xmpp:jingle:apps:rtp:rtp-hdrext:0"
+
+PLUGIN_INFO = {
+ C.PI_NAME: "Jingle RTP Header Extensions Negotiation",
+ C.PI_IMPORT_NAME: "XEP-0294",
+ C.PI_TYPE: "XEP",
+ C.PI_MODES: C.PLUG_MODE_BOTH,
+ C.PI_PROTOCOLS: ["XEP-0294"],
+ C.PI_DEPENDENCIES: ["XEP-0167"],
+ C.PI_RECOMMENDATIONS: [],
+ C.PI_MAIN: "XEP_0294",
+ C.PI_HANDLER: "yes",
+ C.PI_DESCRIPTION: _("""Jingle RTP Header Extensions Negotiation"""),
+}
+
+
+class XEP_0294:
+ def __init__(self, host):
+ log.info(f"plugin {PLUGIN_INFO[C.PI_NAME]!r} initialization")
+ host.trigger.add("XEP-0167_parse_sdp_a", self._parse_sdp_a_trigger)
+ host.trigger.add(
+ "XEP-0167_generate_sdp_content", self._generate_sdp_content_trigger
+ )
+ host.trigger.add("XEP-0167_parse_description", self._parse_description_trigger)
+ host.trigger.add("XEP-0167_build_description", self._build_description_trigger)
+
+ def get_handler(self, client):
+ return XEP_0294_handler()
+
+ def _parse_extmap(self, parts: List[str], application_data: dict) -> None:
+ """Parse an individual extmap line and fill application_data accordingly"""
+ if "/" in parts[0]:
+ id_, direction = parts[0].split("/", 1)
+ else:
+ id_ = parts[0]
+ direction = None
+ uri = parts[1]
+ attributes = parts[2:]
+
+ if direction in (None, "sendrecv"):
+ senders = "both"
+ elif direction == "sendonly":
+ senders = "initiator"
+ elif direction == "recvonly":
+ senders = "responder"
+ elif direction == "inactive":
+ senders = "none"
+ else:
+ log.warning(f"invalid direction for extmap: {direction}")
+ senders = "sendrecv"
+
+ rtp_hdr_ext_data: Dict[str, Union[str, dict]] = {
+ "id": id_,
+ "uri": uri,
+ "senders": senders,
+ }
+
+ if attributes:
+ parameters = {}
+ for attribute in attributes:
+ name, *value = attribute.split("=", 1)
+ parameters[name] = value[0] if value else None
+ rtp_hdr_ext_data["parameters"] = parameters
+
+ application_data.setdefault("rtp-hdrext", {})[id_] = rtp_hdr_ext_data
+
+ def _parse_sdp_a_trigger(
+ self,
+ attribute: str,
+ parts: List[str],
+ call_data: dict,
+ metadata: dict,
+ media_type: str,
+ application_data: Optional[dict],
+ transport_data: dict,
+ ) -> None:
+ """Parse "extmap" and "extmap-allow-mixed" attributes"""
+ if attribute == "extmap":
+ if application_data is None:
+ call_data.setdefault("_extmaps", []).append(parts)
+ else:
+ self._parse_extmap(parts, application_data)
+ elif attribute == "extmap-allow-mixed":
+ if application_data is None:
+ call_data["_extmap-allow-mixed"] = True
+ else:
+ application_data["extmap-allow-mixed"] = True
+ elif (
+ application_data is not None
+ and "_extmaps" in call_data
+ and "rtp-hdrext" not in application_data
+ ):
+ extmaps = call_data.pop("_extmaps")
+ for parts in extmaps:
+ self._parse_extmap(parts, application_data)
+ elif (
+ application_data is not None
+ and "_extmap-allow-mixed" in call_data
+ and "extmap-allow-mixed" not in application_data
+ ):
+ value = call_data.pop("_extmap-allow-mixed")
+ application_data["extmap-allow-mixed"] = value
+
+ def _generate_sdp_content_trigger(
+ self,
+ session: dict,
+ local: bool,
+ idx: int,
+ content_data: dict,
+ sdp_lines: List[str],
+ application_data: dict,
+ app_data_key: str,
+ media_data: dict,
+ media: str,
+ ) -> None:
+ """Generate "extmap" and "extmap-allow-mixed" attributes"""
+ rtp_hdrext_dict = media_data.get("rtp-hdrext", {})
+
+ for id_, ext_data in rtp_hdrext_dict.items():
+ senders = ext_data.get("senders")
+ if senders in (None, "both"):
+ direction = "sendrecv"
+ elif senders == "initiator":
+ direction = "sendonly"
+ elif senders == "responder":
+ direction = "recvonly"
+ elif senders == "none":
+ direction = "inactive"
+ else:
+ raise exceptions.InternalError(
+ f"Invalid senders value for extmap: {ext_data.get('senders')}"
+ )
+
+ parameters_str = ""
+ if "parameters" in ext_data:
+ parameters_str = " " + " ".join(
+ f"{k}={v}" if v is not None else f"{k}"
+ for k, v in ext_data["parameters"].items()
+ )
+
+ sdp_lines.append(
+ f"a=extmap:{id_}/{direction} {ext_data['uri']}{parameters_str}"
+ )
+
+ if media_data.get("extmap-allow-mixed", False):
+ sdp_lines.append("a=extmap-allow-mixed")
+
+ def _parse_description_trigger(
+ self, desc_elt: domish.Element, media_data: dict
+ ) -> None:
+ """Parse the and elements"""
+ for rtp_hdrext_elt in desc_elt.elements(NS_JINGLE_RTP_HDREXT, "rtp-hdrext"):
+ id_ = rtp_hdrext_elt["id"]
+ uri = rtp_hdrext_elt["uri"]
+ senders = rtp_hdrext_elt.getAttribute("senders", "both")
+ # FIXME: workaround for Movim bug https://github.com/movim/movim/issues/1212
+ if senders in ("sendonly", "recvonly", "sendrecv", "inactive"):
+ log.warning("Movim bug workaround for wrong extmap value")
+ if senders == "sendonly":
+ senders = "initiator"
+ elif senders == "recvonly":
+ senders = "responder"
+ elif senders == "sendrecv":
+ senders = "both"
+ else:
+ senders = "none"
+
+ media_data.setdefault("rtp-hdrext", {})[id_] = {
+ "id": id_,
+ "uri": uri,
+ "senders": senders,
+ }
+
+ parameters = {}
+ for param_elt in rtp_hdrext_elt.elements(NS_JINGLE_RTP_HDREXT, "parameter"):
+ try:
+ parameters[param_elt["name"]] = param_elt.getAttribute("value")
+ except KeyError:
+ log.warning(f"invalid parameters (missing name): {param_elt.toXml()}")
+
+ if parameters:
+ media_data["rtp-hdrext"][id_]["parameters"] = parameters
+
+ try:
+ next(desc_elt.elements(NS_JINGLE_RTP_HDREXT, "extmap-allow-mixed"))
+ except StopIteration:
+ pass
+ else:
+ media_data["extmap-allow-mixed"] = True
+
+ def _build_description_trigger(
+ self, desc_elt: domish.Element, media_data: dict, session: dict
+ ) -> None:
+ """Build the and elements if possible"""
+ for id_, hdrext_data in media_data.get("rtp-hdrext", {}).items():
+ rtp_hdrext_elt = desc_elt.addElement((NS_JINGLE_RTP_HDREXT, "rtp-hdrext"))
+ rtp_hdrext_elt["id"] = id_
+ rtp_hdrext_elt["uri"] = hdrext_data["uri"]
+ senders = hdrext_data.get("senders", "both")
+ if senders != "both":
+ # we must not set "both" senders otherwise calls will fail with Movim due
+ # to https://github.com/movim/movim/issues/1213
+ rtp_hdrext_elt["senders"] = senders
+
+ for name, value in hdrext_data.get("parameters", {}).items():
+ param_elt = rtp_hdrext_elt.addElement((NS_JINGLE_RTP_HDREXT, "parameter"))
+ param_elt["name"] = name
+ if value is not None:
+ param_elt["value"] = value
+
+ if media_data.get("extmap-allow-mixed", False):
+ desc_elt.addElement((NS_JINGLE_RTP_HDREXT, "extmap-allow-mixed"))
+
+
+@implementer(iwokkel.IDisco)
+class XEP_0294_handler(XMPPHandler):
+ def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
+ return [disco.DiscoFeature(NS_JINGLE_RTP_HDREXT)]
+
+ def getDiscoItems(self, requestor, target, nodeIdentifier=""):
+ return []