Now that sockopt_init_user() was already merged, builds a user-backed
sockopt_t from the __user pair. A getsockopt leaf can then take
a sockopt_t behind a thin __user wrapper: the wrapper builds it, calls
the leaf, and writes the length back to optlen. The leaf copies with
copy_to_iter() instead of copy_to_user().

Convert four more leaves the way udp and raw already were: ipv6 raw
(do_rawv6_getsockopt), ieee802154 dgram, phonet pep, and tls
(do_tls_getsockopt and its per-option helpers). 

Converting phonet surfaced a pre-existing bug: pep_getsockopt() clamps the
length it reports but writes a full int with put_user(), overrunning an
optval buffer shorter than sizeof(int). It is fixed in its own patch, with
a Fixes: tag, before the phonet conversion, so it can be backported alone.

The last patch adds getsockopt_iter selftest fixtures for rawv6,
ieee802154, phonet and tls, checking the returned length and errno across
exact, oversized and short buffers, an unknown optname and a bad level.

For full motivation about these changes, please check the initial thread
at link
https://lore.kernel.org/all/20260401-getsockopt-v2-0-611df6771aff@debian.org/#t (local)

Signed-off-by: Breno Leitao <leitao@debian.org>
---
Changes in v2:
- Replace min_t() by umin() (David)
- Link to v1: https://patch.msgid.link/20260716-getsockopt_phase4-v1-0-4f45cb12dce7@debian.org

---
Breno Leitao (7):
      ipv6: raw: drop unused level argument from do_rawv6_getsockopt
      ipv6: raw: convert do_rawv6_getsockopt to sockopt_t
      ieee802154: convert dgram getsockopt to sockopt_t
      phonet: pep: do not write beyond optlen in getsockopt
      phonet: pep: convert getsockopt to sockopt_t
      tls: convert getsockopt to sockopt_t
      selftests: net: getsockopt_iter: cover rawv6, ieee802154, phonet and tls

 net/ieee802154/socket.c                       |  38 ++-
 net/ipv6/raw.c                                |  27 +-
 net/phonet/pep.c                              |  36 ++-
 net/tls/tls_main.c                            |  80 +++--
 tools/testing/selftests/net/getsockopt_iter.c | 424 ++++++++++++++++++++++++++
 5 files changed, 533 insertions(+), 72 deletions(-)
---
base-commit: f6f3b36c15ed44de1fbb44e645e4fae8c4a4453e
change-id: 20260715-getsockopt_phase4-180209cfc60a

Best regards,
--  
Breno Leitao [off-list ref]