NET_SOCKETS_OFFLOAD conflicts with POSIX_API

[aport]

Describe the bug
When using NET_SOCKETS_OFFLOAD, the symbol NET_SOCKETS_POSIX_NAMES is selected. This symbol conflicts with POSIX_API.

To Reproduce
Steps to reproduce the behavior:

1. Select CONFIG_NET_SOCKETS_OFFLOAD=y
2. Select CONFIG_POSIX_API=y
3. west build
4. See error in configuration conflict

Expected behavior
I should be able to use NET_SOCKETS_OFFLOAD and POSIX_API at the same time. NET_SOCKETS_OFFLOAD should not depend on NET_SOCKETS_POSIX_NAMES.

Impact
I cannot use POSIX_API when using NET_SOCKETS_OFFLOAD.

Additional context
A similar issue was reported in #17353. It sounds like POSIX_API is the "preferred" way of using POSIX BSD sockets in my application. Perhaps NET_SOCKETS_POSIX_NAMES should be deprecated and removed, with breakages fixed where necessary.

[rlubos]

Since socket offloading is now done underneath zsock_* API, select NET_SOCKETS_POSIX_NAMES in NET_SOCKETS_OFFLOAD option is just a historical residue, it should be safe to remove it from there. Of course, some of the samples, that relied on NET_SOCKETS_POSIX_NAMES being enabled automatically will need some minor tweaks in prj.conf (not sure how many of them, if any).

As for deprecating NET_SOCKETS_POSIX_NAMES, it sounds like a good idea to do some cleanup, I'm not sure yet though how big task that would be (i. e. if there are any other consequences other than switching to a different header).

[aport]

It looks like the ublox-sara-r4 driver breaks when NET_SOCKETS_POSIX_NAMES is not selected, because it uses POSIX types and functions.

Should drivers like these include <posix/poll.h> and other associated headers? Or should they instead use the native Zephyr types zsock_pollfd and zsock_poll() and not muck about with the POSIX abstractions?

[carlescufi]

@aport is this now closed by #26061 or do we need additional clarifications?

[aport]

@carlescufi as far as I can tell two other drivers will fail to build if the dependency between NET_SOCKETS_OFFLOAD and NET_SOCKETS_POSIX_NAMES is cut.

the files drivers/wifi/simplelink/simplelink_sockets.c and drivers/wifi/eswifi/eswifi_socket_offload.c are built when NET_SOCKETS_OFFLOAD is selected, but use raw POSIX types so they should be migrated as well.

I do not have that hardware but I would be happy to submit a PR for review.

[carlescufi]

@carlescufi as far as I can tell two other drivers will fail to build if the dependency between NET_SOCKETS_OFFLOAD and NET_SOCKETS_POSIX_NAMES is cut.

the files drivers/wifi/simplelink/simplelink_sockets.c and drivers/wifi/eswifi/eswifi_socket_offload.c are built when NET_SOCKETS_OFFLOAD is selected, but use raw POSIX types so they should be migrated as well.

I do not have that hardware but I would be happy to submit a PR for review.

Thank you very much for the PR. I will wait until the TI maintainer has approved and then I'll merge it.

[aport]

Just to clarify, this specific issue should be closed when NET_SOCKETS_OFFLOAD no longer selects NET_SOCKETS_POSIX_NAMES. The two PRs I've submitted address the build errors that this removal would have introduced.

So if #26129 is okay and merged, there will be one more PR that modifies the Kconfig to remove this dependency.

I was going to add the change to the PR in question but I felt the changes should be isolated. I could add the Kconfig change as a separate commit to PR #26129 if the team feels that is a better option. Please let me know.