[PATCH net-next v2 0/4] net: convert UDP getsockopt to sockopt_t

[Breno Leitao <leitao@debian.org>]

The leaf proto_ops getsockopt callbacks have been moving to the new
getsockopt_iter()/sockopt_t interface.

I was trying to get SMC into getsockop and retire .getsockopt, but,
I found the best approach is to keep converting other protocols.

This series starts the same conversion one layer down, at the struct proto
getsockopt path, beginning with UDP.

Example of the current code.

	static int udp_getsockopt(struct sock *sk, int level, int optname,
				char __user *optval, int __user *optlen)
	{
		if (level == SOL_UDP)
			return udp_lib_getsockopt(sk, level, optname, optval, optlen);
		return ip_getsockopt(sk, level, optname, optval, optlen);
	}

We want udp_getsockopt to go to .getsockopt_iter, and there are two
approaches in this case:

1) Create a patchset that moves both of them to getsockopt_iter, which
   is will be a huge change (ip_getsockopt() is used in many places)

2) Break this down, and transform from bottoms up. First
   udp_lib_getsockopt() up to the point we can easily convert
   others, such as ip_getsockopt().

I am taking the approach 2), so, the intermediate code will be something
like:

static int udp_getsockopt(struct sock *sk, int level, int optname,
                          char __user *optval, int __user *optlen)
{
        sockopt_t opt;
        int err;

        if (level != SOL_UDP)
                return ip_getsockopt(sk, level, optname, optval, optlen);

	// Convert optlen/optval in sockopt // (first patch)

        err = udp_lib_getsockopt(sk, level, optname, &opt);
}

The work is bottom-up and mergeable in small steps: a protocol's inner
getsockopt helper is switched to sockopt_t behind its existing thin
__user wrapper, one patch at a time.

Once every inner helper speaks sockopt_t, a later series flips the shared
struct proto.getsockopt and inet_connection_sock_af_ops.getsockopt signatures
and drops the transitional wrappers.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
Changes in v2:
- Check for invalid `len` at call site (Stanlislav)
- Do not rewrite `optlen` on error path (Sashiko)
- Converted ipv4 raw
- Expanded the selftest to test this new helper.
- Link to v1: https://lore.kernel.org/r/20260612-getsockopt_phase2-v1-0-7b01f1f5d106@debian.org

---
Breno Leitao (4):
      net: add sockopt_init_user() for getsockopt conversion
      udp: convert udp_lib_getsockopt to sockopt_t
      ipv4: raw: convert do_raw_getsockopt to sockopt_t
      selftests: net: getsockopt_iter: add raw ICMP_FILTER coverage

 include/linux/net.h                           | 23 +++++++
 include/net/udp.h                             |  2 +-
 net/ipv4/raw.c                                | 41 ++++++-----
 net/ipv4/udp.c                                | 39 ++++++++---
 net/ipv6/udp.c                                | 19 +++++-
 tools/testing/selftests/net/getsockopt_iter.c | 97 +++++++++++++++++++++++++++
 6 files changed, 191 insertions(+), 30 deletions(-)
---
base-commit: c8459ee2fef502d6ef6c063751c33d9ac7943eab
change-id: 20260611-getsockopt_phase2-cd495a0115ca

Best regards,
-- 
Breno Leitao <leitao@debian.org>