Add support for RecvOrigDstAddr on Linux

[brianmay]

Fixes #1767

[brianmay]

Still trying to work out why this doesn't work. But is a start.

Also not sure if I should use RecvOrigDstAddr or OrigDstAddr.

[asomers]

These new symbols are also defined for Android and FreeBSD. You should enable them there.

[brianmay]

@asomers Will do so, thanks.

I am not actually sure what these functions are suppose to be returning for non-TPROXY connections. Seem to be getting random addresses, which is causing the tests to fail. Not sure if that is normal or not.

Setting up TPROXY firewall rules probably an overkill for these tests.

[brianmay]

Also for some reason this works:

let mut space = cmsg_space!(libc::in_addr, [u8; 0]);

But this fails with MSG_CTRUNC:

let mut space = cmsg_space!(libc::in_addr);

I have no idea what is going on here.

[brianmay]

I am also a bit puzzled in that some Linux platforms don't appear to be running the test_recvif_ipv6 test, and some don't appear to be running the test_recvif_ipv4 test either.

[asomers]

Also for some reason this works:

let mut space = cmsg_space!(libc::in_addr, [u8; 0]);

But this fails with MSG_CTRUNC:

let mut space = cmsg_space!(libc::in_addr);

I have no idea what is going on here.

That's because in_addr is the wrong datatype. According to the FreeBSD man page at least, IP_ORIGDSTADDR sends its message as a struct sockaddr_in.

[brianmay]

OK, fixed that, was confused reading an existing test.

Trying to run a local test with TPROXY, but first need to debug why my TPROXY UDP firewall rules don't appear to be working...

[brianmay]

All tests pass now when run locally....

[brianmay]

Some of the Linux targets are failing tests. Wonder if this is a Linux compile time option.

[brianmay]

Confirmed it works with a really hackish TPROXY UDP client now.

Looks like values need network byte ordering conversion, was expecting that.

[asomers]

The ENOPROTOOPT errors are probably due to lack of support in QEMU user mode emulation. There are a bunch of tests that have to be disabled due to that. You can add #[cfg_attr(qemu, ignore)] to those tests.

[brianmay]

Done.

[asomers]

Mostly looks good, but for the naming. And don't forget to add a CHANGELOG entry.

[brianmay]

Added changelog entry.

[asomers]

bors r+

[bors]

Build succeeded:

• Android aarch64
• Android arm
• Android armv7
• Android i686
• Android x86_64
• DragonFly BSD x86_64
• FreeBSD 12 amd64 & i686
• FreeBSD 14 amd64 & i686
• Fuchsia x86_64
• Haiku x86_64
• Illumos
• iOS aarch64
• iOS x86_64
• Linux aarch64
• Linux arm gnueabi
• Linux arm-musleabi
• Linux armv7 gnueabihf
• Linux armv7 uclibceabihf
• Linux i686
• Linux i686 musl
• Linux MIPS
• Linux MIPS64
• Linux MIPS64 el
• Linux mipsel
• Linux powerpc
• Linux powerpc64
• Linux powerpc64le
• Linux s390x
• Linux x32
• Linux x86_64
• Linux x86_64 musl
• macOS aarch64
• macOS x86_64
• Minver
• NetBSD x86_64
• OpenBSD x86_64
• Redox x86_64
• Rust Formatter
• Rust Stable

[asomers]

BTW, I just added IPV6_ORIGDSTADDR to the ip6(4) man page on FreeBSD.