Disabling IPv6 support

[gavanderhoorn]

The platform I'm trying to build the client for does not offer support for IPv6.

While it doesn't appear there are many places where AF_INET6 et al. is referenced, I wanted to ask whether there is a way to disable looking for/using IPv6 at configure time (CMake option perhaps)?

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Edit: I'm running into this as I'm trying to build the posix set of UDP/TCP transports. I could create a custom transport and make it "IPv6-less", but I'm hoping there would be a more efficient way of achieving this.

[pablogs9]

Where is failing your build? Which are the defines or functions in Micro XRCE-DDS Client transports that are not defined in your system? Just AF_INET6?

[gavanderhoorn]

Yes, essentially all files referring to AF_INET6, which I believe are these:

./src/c/profile/transport/ip/ip_posix.c
./src/c/profile/transport/ip/ip_windows.c
./src/c/profile/transport/ip/tcp/tcp_transport_posix.c
./src/c/profile/transport/ip/tcp/tcp_transport_windows.c
./src/c/profile/transport/ip/udp/udp_transport_posix.c
./src/c/profile/transport/ip/udp/udp_transport_posix_nopoll.c
./src/c/profile/transport/ip/udp/udp_transport_windows.c

I could also #define AF_INET6 .. to something, but having a configuration option (and accompanying #ifdefs perhaps in the code) would communicate intent much better I believe (ie: setting UCLIENT_PROFILE_UDPv6=OFF clearly communicates IPv6 support for UDP is disabled).

[pablogs9]

Basically, those files are not going to be built if you are in a non-windows platform:

./src/c/profile/transport/ip/ip_windows.c
./src/c/profile/transport/ip/tcp/tcp_transport_windows.c
./src/c/profile/transport/ip/udp/udp_transport_windows.c

If you are building the library with a CMake cross-compilation toolchain, is possible to add to your toolchain file:

add_compile_definitions(AF_INET6=AF_INET)

If you are building the library in the platform using a CMake call you can do:

cmake .. -DCMAKE_C_FLAGS=-DAF_INET6=AF_INET

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If you want to contribute a PR with an implementation of your proposal, it will be really welcomed. Thanks!

[gavanderhoorn]

I might contribute a PR, but I'd need some more information/guidance.

Would #ifdef-ing the AF_INET6 related code be acceptable?

re: your suggestions: yes, I have something like that right now, but that would be what I'd consider work-arounds.

[pablogs9]

Yes, the approach should be adding something like option(UCLIENT_PROFILE_IPV6 "Enable IPv6 in transports." ON) and then ifdef in every section related to IPv6 in the transports.

[roncapat]

I met the same issue. It would surely be interesting to have this switch for configuration.