Why sslocal redirect mode you set ipv6 only to drop dual stack support but ss-libev hasn't?

[Originalimoc]

crates/shadowsocks-service/src/local/redir/tcprelay/sys/unix/linux.rs

[zonyitoo]

shadowsocks-rust/crates/shadowsocks-service/src/local/redir/tcprelay/sys/unix/linux.rs

Lines 44 to 50 in 91028db

	let set_dual_stack = is_dual_stack_addr(&addr);
	if set_dual_stack {
	// Redirect doesn't support dual-stack
	if let Err(err) = set_ipv6_only(&socket, true) {
	warn!("set IPV6_V6ONLY=true failed, error: {}", err);
	}
	}

I think the comment is very clear: "Redirect doesn't support dual-stack".

dual-stack is only supported in tproxy.

[Originalimoc]

Intentional? But why? I guess it's not implemented? As redir changes no destination port and require special handling of the raw socket at least header data. @zonyitoo

[database64128]

Intentional? But why? I guess it's not implemented?

I think it's probably because redirect predates IPV6_V6ONLY, and no one bothered to implement dual-stack support for it in the kernel, because tproxy is the new way.

[Originalimoc]

Intentional? But why? I guess it's not implemented?

I think it's probably because redirect predates IPV6_V6ONLY, and no one bothered to implement dual-stack support for it in the kernel, because tproxy is the new way.

ss-redir(shadowsocks-libev) supports it.

[zonyitoo]

Did you actually try to run it in dual-stack mode and REDIRECT both IPv4 and IPv6 traffic to this process and it can get the original destination of IPv4 connections successfully?

[Originalimoc]

I don't know if internally "it can get the original destination of IPv4 connections".

But set listen to "::" I can use both v4 and v6.

(Not sure if it opens both v4 and v6 socket internally.)

[zonyitoo]

Please delete these lines:

shadowsocks-rust/crates/shadowsocks-service/src/local/redir/tcprelay/sys/unix/linux.rs

Lines 44 to 50 in 498e6a2

	let set_dual_stack = is_dual_stack_addr(&addr);
	if set_dual_stack {
	// Redirect doesn't support dual-stack
	if let Err(err) = set_ipv6_only(&socket, true) {
	warn!("set IPV6_V6ONLY=true failed, error: {}", err);
	}
	}

then compile a sslocal and test it in your environment.

[zonyitoo]

Confirmed Linux 5.4 REDIRECT supports dual-stack.

[zxlhhyccc]

确认 Linux 5.4 REDIRECT 支持双栈。

Linux 5.15 VPS node cannot be connected

[zonyitoo]

It is a sslocal feature, shouldn’t have anything related to the server.