Problem with French IPTV

[iamnague]

Which version are you using?

v0.13.3 (docker)

Which operating system are you using?

OS

• [ x] Linux
• Windows
• macOS

Architecture

• [x ] amd64
• arm64
• arm7
• arm6

Describe the issue

My ISP (Free, France) is offering IPTV service based on RSTP/RTP. Rstp-simple-server, in proxy configuration, can't dectect this IPTV source: ERR: no UDP packets received recently (maybe there's a firewall/NAT in between)

debug_rtsp-simple-server.txt

This source is UDP/RTP with payload type 33 (MPEG II TS). It works with VLC.
Rstp-simple-server, same configuration, works in proxy mode with a different RSTP/RTP source (payload type 97 for ex).

Describe how to replicate the issue

You need this source to replicate. See attached dump with the ko source, and a good one.

Did you attach a network dump?

captures.zip

[aler9]

Hello, to solve this i need

• 30 secs of data between VLC and the IPTV (use RTSP, not just RTP)
• 30 secs of data between rtsp-simple-server and the IPTV

Unfortunately your dumps contained only UDP packets, and don't contain the RTSP handshake - we have to find out whether

• there's a different handshake
• NAT is not opened correctly
• there's something else

Furthermore, please try the undockerized version too.

[iamnague]

Hello @aler9 , thanks for your help.

Here the requested pcap dumps: captures2.zip

I hope it can help you.

[iamnague]

Hello @aler9,
FYI, I've tried last release with the undockerized version, on a different host OS (Ubuntu 16.04) same issue:

./rtsp-simple-server
2021/02/01 14:34:31 [I] [0/0/0] rtsp-simple-server v0.14.0
2021/02/01 14:34:31 [I] [0/0/0] [UDP/RTP listener] opened on 0.0.0.0:8000
2021/02/01 14:34:31 [I] [0/0/0] [UDP/RTCP listener] opened on 0.0.0.0:8001
2021/02/01 14:34:31 [I] [0/0/0] [TCP/RTSP listener] opened on 0.0.0.0:8554
2021/02/01 14:34:31 [I] [0/0/0] [path proxied1] [rtsp source] started
2021/02/01 14:34:31 [I] [0/0/0] [path proxied1] [rtsp source] connecting
2021/02/01 14:34:31 [I] [0/0/0] [path proxied1] [rtsp source] ready
2021/02/01 14:34:41 [I] [0/0/0] [path proxied1] [rtsp source] ERR: no UDP packets received recently (maybe there's a firewall/NAT in between)

[aler9]

Hello, what happens is a very strange thing.

The server tells the client that the UDP ports are 32792-32793

RTSP/1.0 200 OK
Cseq: 3
Server: fbxrtspd/1.2 Freebox RTSP server
Public: DESCRIBE, OPTIONS, SETUP, TEARDOWN, PLAY, PAUSE
X-Freebox-ANPT-Range: 4004334049/4004334049/4004334049/4004334049
Session: H20gKSxsvfwCX0i;timeout=30
Transport: RTP/AVP;unicast;mode=play;destination=212.27.38.254;client_port=48230-48231;server_port=32792-32793

But then the server uses two completely different ports to send packets (48230-48231)...

This happens with both VLC and rtsp-simple-server, but the former doesn't check the sender ports, while the latter does for security reasons.

[aler9]

In my opinion you can do 3 things:

• check whether your NAT changes UDP source ports
• if this is not the case, write to the TV provider and tell them to fix their RTSP server to send the right server port
• anyway, use TCP

paths:
  mypath:
    source: rtsp://
    sourceProtocol: tcp

I'm sorry but i don't want to remove the security check of the UDP source ports.

[iamnague]

Hello @aler9
Thank you very much for your help!
Indeed, I focus my troubleshooting on client_port and I never checked server_port. You are right, server_port doesn't match UDP/RTP source port. And it's not my NAT that changes source ports.

Based on RFC2326:

server_port:
        This parameter provides the unicast RTP/RTCP port pair on
        which the server has chosen to receive media data and control
        information.  It is specified as a range, e.g.,
        server_port=3456-3457.

My understanding is that these ports are not mandatory used for UDP/RTP source ports... but let's say that this part of the RFC is
ambiguous.

I've found a dicussion on the TV provider forum about this issue, based on RFC, they won't change the RTSP behavior :(

Is there any chance that you implement a disable "security check" option ?

Edit: this TV provider doesn't support TCP : ERR: bad status code: 461 (Unsupported Transport)

[aler9]

Hello, in my opinion the best solution consists in hacking the code and compiling a custom executable by yourself.

Edit this file, go to this line: https://github.com/aler9/rtsp-simple-server/blob/2b4d22589ca05559afbbce2635ca0a4fa463286b/internal/sourcertsp/source.go#L124

Add

AnyPortEnable: true,

And recompile with Go (go build . ) or Docker (make release)

In the meanwhile, write to the IPTV provider, they're causing problems that can't be addressed by breaking specifications.

[iamnague]

Hello, thanks for your answer. I'll give a try to compile the code myself but I'll loose the ability to easily deploy and maintain the app.

What specifications are you reffering to ? According to RFC2326, my IPTV provider is not breaking anything....