Add some basic support for offering ice-lite using rtpproxy's

module with the same name.

sippy/Rtp_proxy_session.py

@@ -29,6 +29,7 @@
 from hashlib import md5
 from random import random
 from time import time
+from urllib.parse import unquote
 try:
     from _thread import get_ident
 except ImportError:
@@ -104,11 +105,17 @@ class update_result():
     sendonly = None
     dtls_mode = None
     dtls_fingerprint = None
+    ice_lufrag = None
+    ice_lpwd = None
+    ice_candidates = None
 
 DTLS_TRANSPORTS = ('UDP/TLS/RTP/SAVP', 'UDP/TLS/RTP/SAVPF')
 DTLS_ATTRS = ('setup', 'fingerprint', 'rtcp', 'ssrc')
 DTLS_ATTRS_RM = tuple([a for a in DTLS_ATTRS if a != 'ssrc'])
 
+ICE_ATTRS = ('ice-ufrag', 'ice-pwd')
+ICE_ATTRS_RM = ICE_ATTRS + ('candidate', 'ice-options', 'rtcp-mux')
+
 class _rtpps_side(object):
     session_exists = False
     codecs = None
@@ -118,6 +125,7 @@ class _rtpps_side(object):
     oh_remote = None
     repacketize = None
     gateway_dtls = 'pass'
+    deice = False
     soft_repacketize = False
     after_sdp_change = None
     needs_new_port = False
@@ -194,11 +202,16 @@ def update_result(self, result, up):
             return
         ur = update_result()
         if len(t0) > 1:
-            subc_res = t0[1].lstrip()
-            if subc_res == '-1':
+            subc_ress = t0[1].split('&&')
+            dtls_res = subc_ress.pop(0).strip()
+            if dtls_res == '-1':
                 up.result_callback(None, up.rtpps, *up.callback_parameters)
                 return
-            ur.dtls_mode, ur.dtls_fingerprint = subc_res.split(' ', 1)
+            ur.dtls_mode, ur.dtls_fingerprint = dtls_res.split(' ', 1)
+            if len(subc_ress) > 0:
+                ice_res = subc_ress.pop(0).strip().split()
+                ur.ice_lufrag, ur.ice_lpwd = ice_res[:2]
+                ur.ice_candidates = [unquote(r[2:]) for r in ice_res[2:]]
         ur.rtpproxy_port = int(t1[0])
         if ur.rtpproxy_port == 0:
             up.result_callback(None, up.rtpps, *up.callback_parameters)
@@ -297,6 +310,8 @@ def _on_sdp_change(self, rtpps, sdp_body, result_callback, en_excpt):
             if otherside.gateway_dtls == 'dtls':
                 up.subcommands.append('M4:1 S')
                 otherside.transports[si] = 'UDP/TLS/RTP/SAVP'
+            if otherside.deice:
+                up.subcommands.append('M5:1 S')
             if self.gateway_dtls == 'dtls' and sect.m_header.transport in DTLS_TRANSPORTS:
                 adict = dict([(x.name, x.value) for x in sect.a_headers
                               if x.name in DTLS_ATTRS])
@@ -318,6 +333,20 @@ def _on_sdp_change(self, rtpps, sdp_body, result_callback, en_excpt):
                 up.subcommands.append(subcommand)
                 if otherside.gateway_dtls == 'rtp':
                     otherside.transports[si] = 'RTP/AVP'
+            if self.deice:
+                adict = dict([(x.name, x.value) for x in sect.a_headers
+                              if x.name in ICE_ATTRS])
+                for rattr in ('ice-ufrag', 'ice-pwd'):
+                    if rattr not in adict:
+                        raise SdpParseError(f'Missing ICE {rattr} parameter')
+                subcommand = f'M5:1 A {adict["ice-ufrag"]} {adict["ice-pwd"]}'
+                up.subcommands.append(subcommand)
+                for cand in (x.value for x in sect.a_headers
+                             if x.name == 'candidate'):
+                    pts = cand.split(None, 4)
+                    if pts[2].lower() != 'udp':
+                        continue
+                    up.subcommands.append(f'M5:1 C {cand}')
             up.callback_parameters = (sdp_body, sect, sects, result_callback)
             self.update(up)
         return
@@ -335,11 +364,23 @@ def _sdp_change_finish(self, ur, rtpps, sdp_body, sect, sects, result_callback):
                 for dtls_hdr in [x for x in sect.a_headers
                                  if x.name in DTLS_ATTRS_RM]:
                     sect.a_headers.remove(dtls_hdr)
+            if self.deice:
+                for ice_hdr in [x for x in sect.a_headers if x.name in ICE_ATTRS_RM]:
+                    sect.a_headers.remove(ice_hdr)
             if ur.dtls_fingerprint:
                 for dtls_hdr in [x for x in sect.a_headers if x.name in DTLS_ATTRS_RM]:
                     sect.a_headers.remove(dtls_hdr)
                 sect.addHeader('a', F'setup:{ur.dtls_mode}')
                 sect.addHeader('a', F'fingerprint:{ur.dtls_fingerprint}')
+            if ur.ice_lufrag:
+                for ice_hdr in [x for x in sect.a_headers if x.name in ICE_ATTRS_RM]:
+                    sect.a_headers.remove(ice_hdr)
+                sect.addHeader('a', 'rtcp-mux');
+                sect.addHeader('a', 'ice-lite')
+                sect.addHeader('a', F'ice-ufrag:{ur.ice_lufrag}')
+                sect.addHeader('a', F'ice-pwd:{ur.ice_lpwd}')
+                for cand in ur.ice_candidates:
+                    sect.addHeader('a', F'candidate:{cand}')
             sect.c_header.atype = ur.family
             sect.c_header.addr = ur.rtpproxy_address
             if sect.m_header.port != 0: