Zephyr patch upstreaming (Phase 205.B)

Purpose. Track the nano-ros Zephyr patches that are generic Zephyr fixes (not nano-ros-specific) and stage everything a maintainer needs to open the upstream PRs. As each lands upstream + ships in a tested Zephyr line, drop it from zephyr/patches.yml + the scripts/zephyr/*-patch.sh equivalent and narrow the tested-version matrix (less drift risk for the 205.A starter template).

This doc does not open PRs — that is human follow-up (Zephyr CLA, a fork on zephyrproject-rtos/zephyr). It packages the diffs, clean commit messages, repro, and the post-merge cleanup so the PR is a copy-paste-and-rebase.

Patches carry inline /* nano-ros: … Phase 180.A … */ markers so we can find them in a workspace. Strip those markers when preparing the upstream branch — upstream wants a generic comment (or none). The commit messages below are already nano-ros-free.

Status

Each in-tree patch exists in two forms that must stay in sync: a .patch (zephyr/patches/<name>-4.4.patch, west patch, Zephyr 4.x) and an anchor-based script (scripts/zephyr/<name>-patch.sh / *-4.4.sh, also covers 3.7 LTS which has no west patch). Upstreaming removes the need for both.

PR 1 — NSOS: implement recvmsg()

Target: zephyrproject-rtos/zephyr → drivers/net/nsos_sockets.c. Source diff: zephyr/patches/nsos-recvmsg-4.4.patch (script: scripts/zephyr/nsos-recvmsg-patch.sh 3.7 / -4.4.sh 4.4).

Commit message:

drivers: net: nsos: implement recvmsg()

The Native Simulator Offloaded Sockets (NSOS) driver leaves nsos_recvmsg()
an ENOTSUP stub. Datagram users that read via recvmsg() (one iovec +
msg_name — the common UDP receive shape) therefore get a hard failure on
every receive and busy-spin the receive thread.

Implement the single-iovec form by delegating to nsos_recvfrom(), reusing
its poll/block handling and host<->guest sockaddr translation. Multi-iovec
recvmsg() remains unsupported (returns ENOTSUP) — no NSOS user needs it yet.

Signed-off-by: <your name> <your email>

Repro / test (before): any native_sim app doing UDP recvmsg() logs UDP recvmsg sock N: ret 0 retcode -1 and spins. After: receives succeed. nano-ros’s just zephyr cyclonedds native_sim e2e exercise this path (test_zephyr_*_cyclonedds_pubsub_e2e).

PR 2 — NSOS: IPv4 multicast setsockopt/getsockopt (guest + host)

Open as one PR — the guest marshalling and the host forwarder are useless apart.

Target: drivers/net/nsos_socket.h + drivers/net/nsos_sockets.c (guest) and drivers/net/nsos_adapt.c (host). Source diffs: zephyr/patches/native-sim-ipproto-ip-4.4.patch + zephyr/patches/nsos-adapt-ipproto-ip-4.4.patch (scripts: scripts/zephyr/native-sim-ipproto-ip-patch{,-4.4}.sh + scripts/zephyr/nsos-adapt-ipproto-ip-patch{,-4.4}.sh).

Commit message:

drivers: net: nsos: support IPv4 multicast socket options

NSOS forwards socket options to the host kernel through the midplane, but
has no IPPROTO_IP arm, so guest setsockopt(IP_ADD_MEMBERSHIP) /
IP_MULTICAST_{IF,TTL,LOOP} return EOPNOTSUPP. A native_sim app can never
join an IPv4 multicast group host-side, so multicast receive is
dead-on-arrival (e.g. RTPS/SPDP discovery).

Add the NSOS_MID_IP_* option constants + struct nsos_mid_ip_mreq
(nsos_socket.h), a NET_IPPROTO_IP case in the guest
nsos_setsockopt/getsockopt that marshals the options into the midplane
(nsos_sockets.c), and the matching NSOS_MID_IPPROTO_IP forwarder in the
host nsos_adapt_setsockopt/getsockopt that unmarshals and calls the real
host setsockopt(IPPROTO_IP, …) (nsos_adapt.c). The membership arm reads the
two leading struct in_addr so one path covers both ip_mreq (8 B) and
ip_mreqn (12 B).

Signed-off-by: <your name> <your email>

Repro / test: before, a native_sim listener never joins 239.255.0.1 and receives no multicast; after, multicast join reaches the host kernel and frames arrive. Covered by nano-ros native_sim cyclonedds discovery e2e.

Candidate NSOS PRs (3.7-line scripts, same rationale)

nsos-getsockname, nsos-getifaddrs, nsos-mcjoin-mreq (scripts/zephyr/nsos-*-patch.sh) are the same class of generic NSOS gap (unimplemented getsockname, getifaddrs, dual-mreq multicast join). They are not yet in patches.yml (4.x added some natively / they were only needed on the 3.7 line). Before upstreaming, re-check each against current Zephyr main — some may already be fixed upstream; drop those, file PRs for the rest with a commit message in the same shape as PR 1/2.

zephyr-lang-rust

scripts/zephyr/cargo-features-patch.sh, rust-cargo-extra-args-patch.sh, and the per-arch target registration (cortex-a9/cortex-r/aarch64-rust-patch.sh) patch modules/lang/rust. Pursue upstream in zephyrproject-rtos/zephyr-lang-rust so the rust examples need no in-tree patch — this also removes the lang-rust-shape-drift the Phase 202.5 version-tolerant patch papers over. Upstream-paced; track here as PRs open.

cyclonedds-on-Zephyr

The five cyclonedds patches (threads, log-flush, sockwaitset, udp-rcvbuf, mcjoin) are baked into the nano-ros cyclonedds fork pin (third-party/dds/cyclonedds), not west patch-delivered. Upstream them to eclipse-cyclonedds/cyclonedds; once released, bump the fork pin to a tag that includes them and drop the local commits.

Post-merge cleanup (per patch, once upstream + in a tested Zephyr release)

1. Confirm the fix is in the Zephyr (or lang-rust / cyclonedds) release the tested pin uses (west.yml 3.7.0 LTS / west-4.4.yml 4.4.0 — see book-internals/src/platform/zephyr-version-support.md).
2. Remove the patches.yml entry and the matching scripts/zephyr/*-patch.sh (both the 3.7 + 4.4 variants). Keep them as long as any supported line still needs them — drop per-line only.
3. Drop the patch invocation from scripts/zephyr/patches/<line>.sh.
4. Update this table + book-internals/src/platform/zephyr-version-support.md’s patch note, and narrow the 205.A template’s tested-version matrix.