[BUG] Setting Socket Options not Allowed on a Group Succeed

[maxsharabayko]

TODO:

• Make a short list of group socket options that are not allowed to be set/get on a group.
• Are there options that are allowed but should not be?
• Fix Documentation, e.g. setting SRTO_BINDTODEVICE on a group does not make sense.
• Improve unit tests of group socket options.

BUGS:

• Getting SRTO_RCVBUF and SRTO_SNDBUF on a group socket fills 8 bytes instead of 4 even if optlen is set to 4.
  PR [core] Fixed getting SRTO_RCVBUF and SRTO_SNDBUF on a group. #3077.

According to the API-socket-options.md document the following options are not supported by a group:

• SRTO_CONGESTION
• SRTO_GROUPCONNECT
• SRTO_RENDEZVOUS
• SRTO_SENDER
• ...

However, at least setting SRTO_RENDEZVOUS to true returns SUCCESS and even tries to establish a rendezvous connection. Looking at the code the rest can also be set on a group without any error.

Can't read on a group:

• SRTO_ISN
• SRTO_VERSION
• ...

Can be set on a group socket, but documented as the opposite

• SRTO_GROUPTYPE
• ...

See PR #3086 with unit tests extended to group socket options.