ListenInfo: Add transport socket flags

[ibc]

Details

• Add a new flags option in TransportListenInfo to specify socket flags.
• Supported flags are:

  /**
  * Disable dual-stack support so only IPv6 is used (only if ip is IPv6).
  */
  ipv6Only?: boolean;
  /**
  * Make different transports bind to the same ip and port (only for UDP).
  * Useful for multicast scenarios with plain transport. Use with caution.
  */
  udpReusePort?: boolean;

• Those flags correspond to the following ones exposed by libuv:
  • https://docs.libuv.org/en/v1.x/udp.html#c.uv_udp_flags
  • https://docs.libuv.org/en/v1.x/tcp.html#c.uv_tcp_bind
• Note that flags.ipv6Only is false by default, which is a behavior change.
• This PR replaces PR #1266 by offering the same functionality in a generic and extensible way, and without making mediasoup responsible of knowing in detail the supported flags/features in each arch/OS.

TODO

• Document in website.

[ibc]

Rust hates me:

error[E0204]: the trait `std::marker::Copy` cannot be implemented for this type
  --> rust/src/data_structures.rs:52:17
   |
52 | #[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash, Deserialize, Serialize)]
   |                 ^^^^
...
67 |     pub flags: Option<Vec<SocketFlag>>,
   |     ---------------------------------- this field does not implement `std::marker::Copy`
   |
note: the `std::marker::Copy` impl for `std::option::Option<std::vec::Vec<data_structures::SocketFlag>>` requires that `std::vec::Vec<data_structures::SocketFlag>: std::marker::Copy`
  --> rust/src/data_structures.rs:67:16
   |
67 |     pub flags: Option<Vec<SocketFlag>>,
   |                ^^^^^^^^^^^^^^^^^^^^^^^
   = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)

For more information about this error, try `rustc --explain E0204`.

[nazar-pc]

Rust hates me:

It helps you write bug-free code. In this case Copy can no longer be derived because Vec is heap-allocated data structure rather than a bag of bytes. Remove Copy from derive if you have to use a vector there.

[ibc]

It helps you write bug-free code. In this case Copy can no longer be derived because Vec is heap-allocated data structure rather than a bag of bytes. Remove Copy from derive if you have to use a vector there.

And what are the consequences of removing Copy from derive in that struct?

[nazar-pc]

And what are the consequences of removing Copy from derive in that struct?

You'll have to call .clone() on it rather than value being implicitly copied (like it happens with u8 for example). Clone typically means there is some side effect of the cloning, in case of vector the biggest side effect is allocation of memory.

[ibc]

@jmillan I've pushed this: https://github.com/versatica/mediasoup/pull/1291/commits/a1405e23abee5dcfd13199d87c767fe5c331f4b6

[threema-lenny]

I stumbled upon this. It would have been nice to mention the switch from setting UV_UDP_IPV6ONLY by default to make it optional and user-supplied in the changelog as it was effectively a breaking change in behaviour.

[ibc]

I stumbled upon this. It would have been nice to mention the switch from setting UV_UDP_IPV6ONLY by default to make it optional and user-supplied in the changelog as it was effectively a breaking change in behaviour.

True. I've updated the PR description and added a note in the CHANGELOG file: https://github.com/versatica/mediasoup/commit/2854761ff1dc984d1d3f31cbf216319c085b2e12