167294ea26
From FS-11833. After FS sends a reINVITE to T38 which gets rejected by peer it is no longer in a state where it can properly answer a reINVITE which requests a change of the media setup. 1. FS sends INVITE (destination is a fax machine) 2. Call connects with "8 101" 3. FS sends reINVITE to T38 4. T38 rejected (488) 5. FS receives INVITE to "8" 6. FS replies with 200 OK without SDP 7. Call fails The bug is related to TFLAG_SDP. This flag is set when a media session is established. And when there's a reINVITE sofia_glue_do_invite() from sofia_glue.c is called and clears the flag again: sofia_clear_flag_locked(tech_pvt, TFLAG_SDP); So when FS sends a reINVITE to T38 the flag gets cleared. But when the reINVITE is rejected with 488 the flag is not set again. It stays cleared. So the call continues with the previously negotiated media, fax passthrough (8 101 in this case), but TFLAG_SDP is not set. So when FS receives a reINVITE at this point it doesn't see the need to renegotiate anything, even though it realizes that 2833 DTMF is now off: 2019-04-30 16:42:12.478025 [DEBUG] switch_core_media.c:5478 Audio Codec Compare [PCMA:8:8000:20:64000:1]/[PCMA:8:8000:20:64000:1] 2019-04-30 16:42:12.478025 [DEBUG] switch_core_media.c:5533 Audio Codec Compare [PCMA:8:8000:20:64000:1] ++++ is saved as a match 2019-04-30 16:42:12.478025 [DEBUG] switch_core_media.c:5802 No 2833 in SDP. Disable 2833 dtmf and switch to INFO When FS doesn't send a reINVITE (fax_enable_t38_request=false) and the reINVITE to "8" is received, TFLAG_SDP is still set and then FS understands that it needs to renegotiate and replies with a 200 OK that includes SDP: 2019-04-30 16:41:19.358028 [DEBUG] switch_core_media.c:5478 Audio Codec Compare [PCMA:8:8000:20:64000:1]/[PCMA:8:8000:20:64000:1] 2019-04-30 16:41:19.358028 [DEBUG] switch_core_media.c:5533 Audio Codec Compare [PCMA:8:8000:20:64000:1] ++++ is saved as a match 2019-04-30 16:41:19.358028 [DEBUG] switch_core_media.c:5802 No 2833 in SDP. Disable 2833 dtmf and switch to INFO 2019-04-30 16:41:19.358028 [DEBUG] sofia.c:8237 skemper was here in line 8232 2019-04-30 16:41:19.358028 [DEBUG] switch_core_media.c:8390 skemper was here in line 8390. 2019-04-30 16:41:19.358028 [DEBUG] switch_core_media.c:8496 Audio params are unchanged for sofia/external/+called_number. 2019-04-30 16:41:19.358028 [DEBUG] sofia.c:8243 Processing updated SDP This fixes the state problem after a rejected T38 reINVITE by setting TFLAG_SDP. Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>
FreeSWITCH
FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to a versatile software implementation that runs on any commodity hardware. From a Raspberry PI to a multi-core server, FreeSWITCH can unlock the telecommunications potential of any device. Combined with our hosted cloud platform, SignalWire, FreeSWITCH can interconnect with the outside world and scale to any size.
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Voice-over-IP services - SIP / SMS - App Integrations
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