# P6 — Config & DNS: per-cluster summary

One-line top-level summary per P6 cluster (detailed entries live in
[`docs/progress-log/p6.md`](docs/progress-log/p6.md)).

- **P6a DONE: `s_conf.c` TKLINE cluster** (`m_tkline`/`m_untkline`/`prep_kline`/`do_kline`/`wdhms2sec`/`tkline_expire` + the `tkconf` list) — the oper temporary-kill family ported to `ircd-common/s_conf.rs` via an `s_conf_link.o` partial port (`-DPORT_TKLINE_P6`; the rest of `s_conf.c`'s config grammar stays C). Handler cluster, not server-reachable (msgtab col 2/3; do_kline emits only local `SCH_NOTICE`→`&NOTICES` notices + reaps local clients). Gates: L1 (`s_conf_tkline_diff`: wdhms2sec corpus + tkconf add/dedup/expire lifecycle with inverses, highest_fd pinned -1) + L2 (`golden_s_conf_tkline`: oper TKLINE notice/UNTKLINE/bad-format, the two-client reap → 465+disconnect, non-oper 481 inverse). No S2S (no IsServer/remote-field/propagation path).
- **P6b DONE: `res.c` `m_dns`** (the resolver/cache debug command — the *last* command handler still in C) — ported to `ircd-common/res.rs` via a `res_link.o` partial port (`-DPORT_DNS_M_DNS`, de-static'ing `cachetop`/`cainfo`/`reinfo`); the resolver proper stays C. **Every `msgtab` handler is now Rust.** Handler cluster, msgtab col 2 (STAT_OPER) only + the `is_allowed(ACL_DNS)` O-line `d` gate. L2 (`golden_s_dns`, `dns_oper.conf`): oper `DNS` stats + `DNS l` empty cache dump, non-oper 481 inverse. No S2S.
- **P6c DONE: `s_conf.c` flags cluster** (the six pure config-flag converters `{iline,pline,oline}_flags_parse`/`_to_string`) — same `s_conf_link.o` partial port (`-DPORT_SCONF_FLAGS_P6`); first bite into the config *grammar*. Utility/callee (none in msgtab). L1 (`s_conf_flags_diff`: all six vs `cref_`) + L2 (`golden_s_conf_flags`, `flags_oper.conf`). No S2S.
- **P6d DONE: `s_conf.c` `match_ipmask`** (the CIDR/#IP-bitmask matcher — a pure leaf predicate over `cptr->ip`/`username`, used by Rust channel ban-matching + the TKLINE/conf-lookup paths) — same `s_conf_link.o` partial port (`-DPORT_SCONF_IPMASK_P6`). Utility/callee. L1 (`s_conf_match_ipmask_diff`: v4-mapped /32//24//0, j-boundary, user@host/cidr, badmask, native v6, each with its inverse) + L2 (`golden_s_conf_match_ipmask`: channel CIDR `+b`). No S2S.
- **P6e DONE: `s_conf.c` `find_admin`/`find_me`** (two leaf read-only walks of the global `conf` list for the `CONF_ADMIN`/`CONF_ME` entry) — same `s_conf_link.o` partial port (`-DPORT_SCONF_FINDADMIN_P6`). Utility/callee. L1 (`s_conf_find_admin_me_diff`: head/non-head/absent/combined-bits incl. inverses, both globals pointed at one list) + L2 (`golden_s_conf_find_admin`: the `ADMIN` command via Rust `m_admin`). No S2S.
- **P6f DONE: `s_conf.c` config-file parser** (`openconf` + `initconf` — the whole `ircd.conf` grammar) — same `s_conf_link.o` partial port (`-DPORT_INITCONF_P6`, un-static'ing `lookup_confhost`); the line lexer is a new **`nom`-based** module (`config_parse.rs` — faithful `process_escapes`→`split_fields` port of the escape/comment pass + `getfield`), the semantic switch builds byte-identical `aConfItem` lists/classes + side effects. Not in msgtab. L1 (`config_parse_diff`: nom `split_fields` vs `cref_getfield`; `s_conf_initconf_diff`: full conf-list build vs `cref_initconf` over A/I/i/O/o/Y/C/c/N/D/H/L/V/Q/B/K/k) + L2 (`golden_s_conf_initconf`: STATS y/i/o over the parsed config). No S2S.
- **P6g DONE: `s_conf.c` `find_Oline`** (the read-only `conf`-list scan `m_oper` uses to resolve `OPER <name> <pass>`: best `CONF_OPS` entry by name `mycmp` + host `match`/`match_ipmask`, honouring `clients < MaxLinks(Class)` with the over-limit `tmp2` fallback) — same `s_conf_link.o` partial port (`-DPORT_SCONF_FINDOLINE_P6`). Utility/callee (`m_oper` calls it). L1 (`s_conf_find_oline_diff`: name/host-glob/CIDR-in-out/over-limit-fallback/wrong-status/empty incl. inverses) + L2 (`golden_s_conf_find_oline`, `find_oline.conf`: a `10.0.0.0/8` O-line that misses the 127.0.0.1 client → 491, vs a `*@*` O-line → 381 — the host/CIDR-miss branch the existing OPER golden can't reach). No S2S (no IsServer/remote-field path).
- **P6h DONE: `s_conf.c` `find_conf*` family** (the seven read-only conf lookups `find_conf_exact`/`find_conf_name`/`find_conf`/`find_conf_host`/`find_conf_host_sid`/`find_conf_ip`/`find_conf_entry`) — same `s_conf_link.o` partial port (`-DPORT_SCONF_FINDCONF_P6`). Utility/callee (none in msgtab; the still-C `s_serv.c`/`s_bsd.c`/`s_misc.c` server-link + registration paths call them). L1 (`s_conf_find_conf_diff`: all seven vs `cref_` over positive + inverse — name/host/status/port/passwd-asymmetry misses, the CONF_OPERATOR over-limit skip, the server-mask `mycmp`-exact-vs-`match`-glob split, the NUL HOSTLEN early-outs, the `find_conf_ip` in-place `@`-split restore; **the differential caught an inverted `!match(passwd,sid)` sid gate in the first draft**) + S2S (`golden_s2s_s_conf_find_conf`: a peer link drives the C/N-line `find_conf` accept + `find_conf_host`/`find_conf_host_sid` leaf/hub checks → byte-identical burst + post-link routing; the 37-test `golden_s2s_*` suite + registration goldens are the broader regression). No client-only L2 numeric.
- **P6i DONE: `s_conf.c` K-line lookup family** (`find_kill`/`find_two_masks`/`find_conf_flags`/`find_denied`) — the read-only K-line / version-mask / deny lookups named in the PLAN P6 row, ported to `ircd-common/s_conf.rs` via the `s_conf_link.o` partial port (`-DPORT_SCONF_FINDKILL_P6`, three guard regions; `find_bounce` stays C). Config-resolved: TKLINE on (find_kill's tkconf→kconf two-pass loop compiles), KLINE off, TIMEDKLINES off (the reply/check_time_interval block not compiled; `timedklines` arg inert). Utility/callees (none in msgtab); the still-C `s_serv.c` `check_version`, Rust `s_user.c` `register_user`, and `ircd.c` resolve to the Rust defs at link. L1 (`s_conf_find_kill_diff`: all four vs `cref_` over positive + inverse — find_kill tkconf/kconf hit, expired-TK fallthrough, OTHERKILL→ident vs KILL→username `check`, port gate, CIDR in/out, '='-numeric-only skip, resolved-hostname match, IsKlineExempt short-circuit, no-user guard; find_two_masks/find_conf_flags status/host/name/no-slash/prefix/strpbrk inverses; find_denied host-scan/reversed/digit-passwd/no-D-line) + L2 (`golden_s_conf_find_kill`, `kline.conf`: a 127.0.0.1 client hits `K|127.0.0.1|…|*|0|` mid-registration → 465 + `K-lined:` Closing Link) + S2S (`golden_s2s_s_conf_find_two_masks`, `vline_reject.conf` = s2s.conf + `V|*||peer.test|`: m_server_estab check_version → find_two_masks → "Bad version" exit). The no-match version-check path is exercised by every other `golden_s2s_*` test; find_denied is reachable only from `try_connections` server auto-connect (not in the golden harness) → L1 only.
- **P6j DONE: `s_conf.c` `find_bounce`** (the RPL_BOUNCE sender — the read-only conf-list scan that emits `010 :Please use this Server/Port instead` to a rejected connection) — ported to `ircd-common/s_conf.rs` via the `s_conf_link.o` partial port (`-DPORT_SCONF_FINDBOUNCE_P6`, one guard region; the mutating `attach`/`detach`/`rehash` family + `lookup_confhost`/`ipv6_convert` stay C). Three dispatch modes by `fd`: `fd>=0` early-reject (cptr NULL → `sprintf`+raw `sendto`), `fd==-1` class-number host match, `fd==-2` host-match-only. Config: `CONF_BOUNCE`=262144, `RPL_BOUNCE`=10. Utility/callee (not in msgtab); callers s_bsd.c (all-conns-in-use), C `count_cnlines`, and Rust `m_nick`/`m_user` (server-only P-line) resolve to the Rust def at link. L1 (`s_conf_find_bounce_diff`: 9 tests diffing **sent bytes** — sendQ via sendto_one for fd<0, socketpair recv for fd>=0 — over host-glob hit/miss, CIDR in/out, class-number host on fd==-1 vs the fd==-2 skip, non-bounce-skip + first-match-wins, the cptr-NULL guard, empty list, and the fd>=0 empty-host write vs non-empty-host no-op) + L2 (`golden_s_conf_find_bounce`, `bounce.conf`: a server-only P-line `P||||16667|0|S|` + `B|127.0.0.1||bounce.elsewhere|7000|` → client NICK on the server-only port → `010` bounce + `Server only port` exit, byte-identical). No S2S (no IsServer/remote-field path; the fd>=0 raw-sendto branch needs MAXCLIENTS conns → L1 only).
- **P6k DONE: `s_conf.c` attach/detach mutating cluster** (`attach_conf`/`detach_conf`/`det_confs_butmask`/`attach_confs`/`attach_confs_host` + the private `is_attached`/`add_cidr_limit`/`remove_cidr_limit`) — the connected component of conf-attachment mutators (grow/shrink `cptr->confs` + the global `conf` list, mutate class refcounts `aconf->clients`/`ConfLinks` and the per-class CIDR-limit patricia trees), ported to `ircd-common/s_conf.rs` via the `s_conf_link.o` partial port (`-DPORT_SCONF_ATTACH_P6`, three guard regions). Config-resolved: ENABLE_CIDR_LIMITS on (add/remove_cidr_limit compile; `pnode->data` void* counter), YLINE_LIMITS_IPHASH on (per-host limit loop walks the IP hash), YLINE_LIMITS_OLD_BEHAVIOUR off (max-links gate `ConfLinks >= ConfMaxLinks`). Utility/callees (none in msgtab); callers — C `attach_Iline`/`count_cnlines`/`s_bsd.c`/`s_serv.c`/`s_service.c` + Rust `register_user`/`m_oper`/`m_umode` — resolve to the Rust defs at link. Gates: L1 (`s_conf_attach_diff`: two fully-isolated worlds via an `Api` of fn-pointers; round-trip/inverse invariants — attach→detach unlink, is_attached idempotency, -3 Y-line-max + -4 CIDR gates, CIDR freed-slot reuse, free-class on maxLinks==-1, illegal-conf removal from global list, det_confs_butmask, attach_confs/host glob-vs-mycmp; zero diff) + L2 (`golden_s_conf_attach`, `ylinemax.conf`: 2 clients in a maxlinks-1 class → bob rejected via attach_conf -3 → "Too many connections", byte-identical; success+detach paths covered pervasively by the registration + golden_s2s_* suite). No S2S (no IsServer/remote-field path; attach_confs C/N + det_confs_butmask SQUIT covered by the 37-test golden_s2s_* establishment/teardown suite). What stays C in s_conf.c is now only `rehash`, `attach_Iline`/`count_cnlines` (callers of this core), and the initconf-private `lookup_confhost`/`ipv6_convert`.
- **P6l DONE: `s_conf.c` `attach_Iline` + `count_cnlines`** (the two callers of the P6k attach/detach core) — the local-client I-line lookup used during registration (`attach_Iline`: scan `conf` for the best `CONF_CLIENT` line matching the client's port/name/host/password, set the +r/kline-exempt conf flags onto `cptr->user->flags`, copy the resolved host into `sockhost`, then `attach_conf`; emits `464 ERR_PASSWDMISMATCH`/`find_bounce` on rejection) and the read-only single-N-line counter used during inbound server-link establishment (`count_cnlines`), ported to `ircd-common/s_conf.rs` via the `s_conf_link.o` partial port (`-DPORT_SCONF_ILINE_P6`, one guard region s_conf.c:483–664). Config-resolved: UNIXPORT off (no unix-socket host branch), XLINE off (no XlineExempt clear), NO_DNS_LOOKUP on (hp usually NULL). Utility/callees (none in msgtab); callers — C `check_client`/`check_server` (s_bsd.c) — resolve to the Rust defs at link. **What stays C in `s_conf.c` is now only `rehash` + the initconf-private `lookup_confhost`/`ipv6_convert`.** Gates: L1 (`s_conf_iline_diff`: two fully-isolated worlds via an `Api` of fn-pointers — happy glob/CIDR/empty-mask attach + the no-I-line `-2` inverse, port gate, password fall-through vs `-8`+`464`, +r/kline-exempt flag-set, hp!=NULL name-match + `get_sockhost`; `count_cnlines` single-N/zero/two/non-server-skip/empty; zero diff over 8 tests) + L2 (`golden_s_conf_iline`, `iline_pass.conf`: a password I-line with no `F` flag → a client sending no `PASS` → `464` + "Bad password" Closing Link, byte-identical). No S2S (neither has an `IsServer` branch / remote-field formatting; `count_cnlines`'s server-link path is covered by the 37-test `golden_s2s_*` link suite).
- **P6m DONE: `s_conf.c` finalize — `rehash` + `ipv6_convert` + `lookup_confhost` + the `conf`/`kconf`/`networkname` data globals** (the last three functions + the last three data globals s_conf.c owned) — ported to `ircd-common/s_conf.rs`, so **`s_conf.c` is now FULLY Rust → `s_conf.o` dropped outright** (added to `PORTED`; the `s_conf_link.o` partial-compile + the `"s_conf.o" => "s_conf_link.o"` link map removed; the cref oracle keeps the unguarded `s_conf.o`). `rehash` = the faithful config reload (free conf/kconf, mark classes `MaxLinks=-1`, `initconf(0)`, close/reopen listeners, re-read MOTD, the sig `1`/`'a'`/`'d'`/`'t'` branches; ULTRIX/USE_SYSLOG off, TKLINE on); `ipv6_convert` = the pure `[user@]addr[/cidr]` canonicaliser (in-place `@`/`/` poke + restore); `lookup_confhost` = numeric host via `inetpton` (the NO_DNS path) / alpha host via the still-C `gethost_byname`, `badlookup` AND16==255 reset. The conf/kconf/networkname globals flip from bindgen externs to `#[no_mangle] pub static mut` defs (list.rs/s_serv.rs importers resolve to them at link, same as `tkconf`/`classes`). `build.rs` expands `IRCDMOTD_PATH` via make → the `IRCD_MOTD_PATH` rustc-env → `ircd_sys::MOTD_PATH`, so the Rust `rehash`'s `read_motd` reads the identical file reference-C does. Utility/callees (none in msgtab); `rehash` reached from Rust `m_rehash` (oper REHASH) + still-C `ircd.c` SIGHUP. Gates: L1 (`s_conf_rehash_diff`: `ipv6_convert` vs `cref_` over bare-v6/user@/cidr/v4-mapped/passthrough + the input-restore invariant) + L2 (`golden_s_serv_maint` REHASH 382 success/481 reject now drives the Rust `rehash`; `golden_s_conf_initconf` boot exercises `lookup_confhost`/`ipv6_convert`). No S2S (no `IsServer`/remote-field path). `lookup_confhost` is `static` in the unguarded oracle → no `cref_` symbol → covered by the boot golden, not L1.
- **P6n DONE: `res.c`'s pure wire-format leaf `res_comp.c`** (the BIND DNS name compression/expansion `ircd_dn_expand`/`ircd_dn_comp`/`__ircd_dn_skipname` + the big-endian integer marshalers `ircd_getshort`/`ircd_getlong`/`ircd__putshort`/`ircd__putlong`) — ported outright to `ircd-common/res_comp.rs` → **`res_comp.o` dropped** (added to `PORTED`; no `_link.o`). Self-contained leaf: `nm --undefined-only` shows zero ircd-internal deps (only libc `memcpy`/`strchr`/`errno`); the 7 BIND `static` helpers (`ns_name_*`/`special`/`printable`/`mklower`/`dn_find`) ported as private Rust fns. Faithful raw-pointer port; `errno` set (`EMSGSIZE`/`ENOENT`) on every error path as the C does. Utility/leaf (none in `msgtab`); callers — still-C `res.c`/`res_mkquery.c` — resolve to the Rust defs at link. Gate: **L1 only** (`res_comp_diff`: get/put match + put→get round-trip; `dn_comp`→`dn_expand` pack/expand round-trip; the compression-pointer reuse diffed as buffer-relative `dnptrs` offsets + emitted wire bytes; a hand-built compressed-pointer message; `dn_skipname` plain/compressed/truncated; the dstsiz-too-small, malformed-pointer, overlength `-1` inverses with `errno` compared). No L2/S2S — pure wire-format leaf with no client/server-reachable command path under the locked config; end-to-end DNS coverage arrives when the resolver proper is ported under a fixture nameserver.
- **P6o DONE: `res.c`'s DNS query-packet builder `res_mkquery.c`** (`ircd_res_mkquery` — forms QUERY/NS_NOTIFY_OP/IQUERY messages into a caller buffer, returns the packet length or `-1`) — ported outright to `ircd-common/res_mkquery.rs` → **`res_mkquery.o` dropped** (added to `PORTED`; no `_link.o`). Deps resolve at link: `ircd_dn_comp`/`ircd__putshort`/`ircd__putlong` are the P6n Rust defs, the resolver-state global `ircd_res` + `ircd_res_init` stay C (res_init.o). **Layout hazard neutralized:** the 12-byte DNS header is written through the **bindgen `HEADER`** bitfield type (size 12, `set_id`/`set_opcode`/`set_rd`/`set_rcode`/`set_qdcount`/`set_ancount`/`set_arcount` byte-identical to the gcc little-endian `nameser_def.h` layout) instead of hand-packing bitfields; `h_errno` set via `__h_errno_location` exactly as the C. Config-resolved: `DEBUG` off → the `RES_DEBUG` printf block not compiled. Utility/leaf (none in `msgtab`); callers — still-C `res.c` (`query_name`/`do_query_*`) — resolve to the Rust def at link. Gate: **L1 only** (`res_mkquery_diff`: Rust vs `cref_` byte-identical packets over QUERY±recurse, NS_NOTIFY_OP with/without the additional-record branch, IQUERY answer section with/without rdata, plus the `-1` inverses — bad op, NULL buf, `buflen<HFIXEDSZ`, and the question-section `buflen`/`dn_comp` overflow — and the shared `++ircd_res.id` side effect diffed identically; both `ircd_res`/`cref_ircd_res` pinned with RES_INIT to skip the nondeterministic `res_init`/`res_randomid` path, a process-global `RES_LOCK` serializing the parallel `#[test]` threads). No L2/S2S — pure wire-format leaf with no client/server-reachable command path under NO_DNS_LOOKUP; end-to-end DNS coverage arrives when the resolver proper (`res.c`+`res_init.c`) is ported under a fixture nameserver.
- **P6p DONE: `res.c`'s resolver-state bootstrap `res_init.c`** (`ircd_res_init` — reads `/etc/resolv.conf` + `LOCALDOMAIN`/`RES_OPTIONS` env into the global `ircd_res`; the static `res_setoptions` it drives; the random message-id `ircd_res_randomid`) — ported outright to `ircd-common/res_init.rs` → **`res_init.o` dropped** (added to `PORTED`; no `_link.o`). The `ircd_res` global moves from C to a Rust `#[no_mangle] static mut` (`MaybeUninit::zeroed`); `res_mkquery.rs`/`res.c`/`s_bsd.c` resolve their `ircd_res`/`ircd_res_init` references to the Rust defs at link. Self-contained leaf — the only non-libc dep is `inetpton` (P1 `support.rs`). Config-resolved: `DEBUG`/`NEXT`/`RESOLVSORT`/`RFC1535`/`HAVE_GETIPNODEBYNAME`/`USELOOPBACK`/`__BIND_RES_TEXT` all OFF → only the simple path compiles (no NetInfo, no sortlist, no debug printfs, default-`dnsrch` derivation active, `inet6`→`RES_USE_INET6`; `AFINET=AF_INET6` so nameservers parse as IPv6). Utility/leaf (none in `msgtab`). Gate: **L1 only** (`res_init_diff`: the `ircd_res` struct produced by `ircd_res_init` diffed vs `cref_` field-by-field — scalars, ndots/nsort bitfields, the 3 `nsaddr_list` `sockaddr_in6` byte-for-byte, `defdname` bytes, `dnsrch[]` as offsets into `defdname` — over the default-`dnsrch`/`LOCALDOMAIN`-search-tokenizer/`RES_OPTIONS` `ndots:`+`inet6`+`RES_MAXNDOTS`-clamp paths, both globals zeroed + `.id` pinned nonzero to skip the nondeterministic `res_randomid`, env-set/init/restore under a process-global `RES_LOCK`; `res_randomid` is nondeterministic → only its `& 0xffff` mask smoke-tested). Boot/registration + `golden_s_dns` goldens confirm the Rust `ircd_res_init`/`ircd_res` boot byte-identical. No L2/S2S (pure leaf, no client/server command path under `NO_DNS_LOOKUP`; end-to-end DNS coverage arrives when the resolver proper `res.c` is ported under a fixture nameserver). **`res.c` is the only DNS file still in C.**
- **P6q DONE: `res.c` cache-hash leaves `hash_number`/`hash_name`** (the two pure DNS-cache bucket hashes — first bite of the `res.c` cache cluster, ported bottom-up from the resolver's dependency floor) — ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_CACHE_P6q`, dropping their bodies + declaring them extern so the still-C cache walkers `find_cache_name`/`add_to_cache`/`rem_cache`/`find_cache_number` call the Rust defs). Both are upstream file-`static`, so a new three-way `RES_CACHE_LINKAGE` macro de-statics them to GLOBAL in the cref oracle's `res.o` (`-DRES_CACHE_EXPOSE`, behavior-neutral; res.o is consumed only by `libcref.a`) so `cref_hash_*` exists for the L1 differential — neutralizing the `l1-cref-static-symbol-limit`. Faithful: `hash_number` is the unrolled `hashv=ip[0]; for i in 1..16 { hashv=2*hashv+ip[i] }` over a **wrapping u32** (`% 1009`=ARES_CACSIZE only at the end; reads exactly 16 bytes = sizeof in6_addr, AFINET=AF_INET6); `hash_name` sums bytes to the first `.`/NUL with **signed-char** promotion (`i8 as i32 as u32`). Utility/leaf (not in `msgtab`). Gate: **L1 only** (`res_hash_diff`: Rust vs `cref_` over 16-byte v6 addrs incl. all-0xff u32-overflow/v4-mapped/high-bit, names incl. empty/dot-first/embedded-dot/8-bit/long; range-checked `[0,1009)`). No L2/S2S (no client/server command path; resolver inert under `NO_DNS_LOOKUP`, cache never populates at runtime — end-to-end DNS coverage arrives when the resolver proper is ported under a fixture nameserver). `golden_s_dns` + boot goldens confirm the still-C cache walkers call the Rust hashes without regression.
- **P6r DONE: `res.c` cache removal/expiry core `rem_list`/`rem_cache`/`expire_cache`/`flush_cache`** (the second bite of the `res.c` cache cluster, building on the P6q hashes) — the connected component that *deletes* cache entries, ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_CACHE_REM_P6r`, generalizing the P6q three-way `RES_CACHE_LINKAGE` to `rem_cache`/`rem_list`). `rem_list` unlinks one entry from `cachetop` **only** (leaves the hash buckets + `incache` untouched — the faithful quirk); `rem_cache` does the full delete (NULL any `local[]->hostp` at this `he`, unlink from `cachetop` + both `hashtable` buckets via the Rust `hash_name`/`hash_number`, free name/aliases/addrs/entry, `incache--` + `ca_dels++`); `expire_cache` reaps the past-due + returns the next poll time; `flush_cache` reaps everything. The cache data globals `hashtable`/`incache` join `cachetop`/`cainfo` on `RES_DNS_STATIC`, now also exposed under `-DRES_CACHE_EXPOSE` so the cref oracle gets `cref_cachetop`/`cref_hashtable`/`cref_incache`/`cref_cainfo` for the L1 isolated worlds. Utility/leaf (not in `msgtab`). Gate: **L1 only** (`res_cache_rem_diff`: two fully-isolated `World`s of fn-pointers + global base pointers, entries hand-built à la `add_to_cache`; flush/expire/rem_cache-hostp/rem_list each with its inverse — flush empties + re-inserts clean, expire keeps survivors in order + returns min-future/`now+AR_TTL`, rem_cache clears a per-world dangling `hostp`, rem_list returns the successor + leaks `incache` by design; zero diff). No L2/S2S (resolver inert under `NO_DNS_LOOKUP`; `golden_s_dns` + registration goldens confirm the still-C cache walkers call the Rust removal core without regression). **Still C in `res.c`:** the resolver proper + the cache build/insert/lookup half (`add_to_cache`/`update_list`/`find_cache_*`/`make_cache`).
- **P6s DONE: `res.c` cache lookup/reorder half `update_list`/`find_cache_name`/`find_cache_number`** (the third bite of the `res.c` port — the half of the hostent cache that *looks up* and *reorders/merges* entries, built on the P6q hashes + P6r removal core) — the connected component ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_CACHE_LOOKUP_P6s`, extending the three-way `RES_CACHE_LINKAGE` to the three upstream file-statics so the still-C `gethost_byname_type`/`gethost_byaddr`/`proc_answer`/`make_cache` callers resolve to the Rust defs at link, and the cref oracle de-statics them to `cref_*` for L1). `update_list` reorders a hit to the `cachetop` head and (if `rptr != NULL`) merges new aliases (T_PTR) / addresses (T_A/T_AAAA) from the ResRQ reply into the cached `hostent` — the gnarly double-`MyRealloc` of the contiguous IP block + the pointer array, then the `FLG_PTR_*` flag update by `addrcount`; `find_cache_name`/`find_cache_number` do the hashed-bucket lookup + the full-list fallback (the fallback's fixed-`s`=alias[0] quirk + the `find_cache_number` `rem_list` degenerate-entry reap preserved), `update_list` on hit, `ca_na_hits`/`ca_nu_hits` counters. Faithful raw-pointer port preserving the C post-increment index walks (`s = h_aliases[i++]`) and the for-loop `continue`→increment semantics. Utility/leaf (not in `msgtab`). Gate: **L1 only** (`res_cache_lookup_diff`: two isolated `World`s of fn-pointers + global base pointers — `cachetop`/`hashtable`/`cainfo`; find_cache_name hashed hit+reorder+counter / name-miss / flags-gate-miss / alias full-list fallback; find_cache_number hashed hit / absent-addr miss / FLG_PTR_VALID gate / multi-addr fallback; update_list rptr=NULL reorder-only + T_PTR alias-merge & T_A addr-merge each with the already-present no-growth inverse; zero diff over 6 tests). No L2/S2S (resolver inert under `NO_DNS_LOOKUP`; `golden_s_dns` + `golden_registration` confirm the still-C build/insert half calls the Rust lookup/reorder core without regression). **Still C in `res.c`:** the resolver proper + the cache **build/insert** half (`add_to_cache`/`make_cache`).
- **P6t DONE: `res.c` cache build/insert half `add_to_cache`/`make_cache`** (the fourth and final bite of the `res.c` cache cluster — the two functions that *create* and *link in* hostent-cache entries, built on the P6q hashes + P6r removal core + P6s lookup/reorder) → **`res.c`'s hostent cache is now FULLY Rust**; only the resolver proper remains C. Ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_CACHE_BUILD_P6t`, extending the three-way `RES_CACHE_LINKAGE` to both upstream file-statics so the still-C `proc_answer` caller of `make_cache` resolves to the Rust def at link, and the cref oracle de-statics them to `cref_*` for L1). `add_to_cache` = list-head push + both hash-bucket links (`hash_name`/`hash_number`) + `++incache > MAXCACHED` LRU tail-evict via `rem_cache` + `ca_adds++`; `make_cache` = dedup-or-build (T_PTR→`find_cache_number` per reply addr / T_A·T_AAAA→`find_cache_name` by name — a hit returns the already-reordered+merged entry; a miss `MyMalloc`s a fresh entry, builds the contiguous IP block + pointer array, **steals** the ResRQ aliases + `h_name` (source nulled), clamps `ttl<600`→600 + `re_shortttl++`, `expireat = timeofday + ttl`, sets the `FLG_A_VALID`/`FLG_AAAA_VALID` flag, then `add_to_cache`). Config: DEBUG off (no Debug blocks), AFINET=AF_INET6 (16-byte IN_ADDR), MAXCACHED 512. Utility/leaf (not in `msgtab`). Gate: **L1 only** (`res_cache_build_diff`: two fully-isolated `World`s of fn-pointers + base pointers incl. `incache`/`reinfo`/`timeofday` — build-by-name A/AAAA with the steal inverse, short-ttl clamp + the ≥600 inverse, dedup-by-name + dedup-by-addr-PTR no-add, multi-addr contiguous-block build, `add_to_cache` LRU boundary at MAXCACHED (evict via ca_dels delta) + the under-cap inverse, both-bucket linkage via the two finders; `timeofday` pinned so `expireat` is deterministic; zero diff over 8 tests). No L2/S2S (resolver inert under `NO_DNS_LOOKUP`, cache never populates at runtime; `golden_s_dns` + `golden_registration` confirm the still-C resolver calls the Rust build/insert core without regression). **Still C in `res.c`:** only the resolver proper (request queue + answer parser + socket I/O).
- **P6u DONE: `res.c` request-queue core `add_request`/`rem_request`/`make_request`/`find_id`** (the first bite of the `res.c` resolver proper — the queue-management primitives the rest of the resolver builds on, ported bottom-up from the outstanding-DNS-request floor after the P6q–P6t cache cluster) — ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_REQ_P6u`: a parallel three-way `RES_REQ_LINKAGE` de-statics the four fns — `extern` in res_link.o so the still-C walkers `del_queries`/`timeout_query_list`/`get_res` resolve to the Rust defs, GLOBAL in the cref oracle for `cref_*` L1, static otherwise — and the `first`/`last` queue heads flip from `static` to `RES_DNS_STATIC` so the Rust core + the still-C walkers share one storage, same as the cache globals). `add_request` tail-appends + `reinfo.re_requests++` (NULL → -1 no-op); `rem_request` unlinks (repointing `last` on tail removal) + frees `he.h_name`/`he.h_aliases[]`/`name`/the node; `make_request` `MyMalloc`+`bzero` + seeds `sentat=timeofday`/`retries=3`/`resend=1`/`srch=-1`/`timeout=4`/`he.h_addrtype=AFINET` + copies the `Link` into `cinfo` + `add_request`; `find_id` linear-scans `first`. Config: AFINET=AF_INET6, DEBUG off (Debug() traces gone), MyFree→`libc::free`. Utility/callees (not in `msgtab`). Gate: **L1 only** (`res_request_diff`: two isolated `World`s of fn-pointers + `first`/`last`/`reinfo` base pointers — make_request seeds+appends (NULL-lp zeroes cinfo), add_request order+counter + the NULL no-op, find_id hit/miss + misses-after-rem, rem_request head/middle/tail unlink+`last`-repoint+free, drained queue `first==last==NULL`+reusable; `timeofday` pinned, a process-global LOCK serializes the parallel threads; zero diff over 8 tests). No L2/S2S (resolver inert under `NO_DNS_LOOKUP`, the queue never populates at runtime; `golden_s_dns` + `golden_registration` confirm the still-C walkers call the Rust queue core without regression). **Still C in `res.c`:** `del_queries`/`timeout_query_list` + the resolver socket/answer half (`send_res_msg`/`do_query_*`/`query_name`/`resend_query`/`proc_answer`/`get_res`/`gethost_*`/`init_resolver`/`cres_mem`).
- **P6v DONE: `res.c` queue walkers `del_queries`/`timeout_query_list`** (the second bite of the `res.c` resolver proper — the reaper/timeout layer that walks the outstanding-DNS request queue, built on the P6u queue core) — ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_WALK_P6v`). `del_queries(cp)` reaps every node whose `cinfo.value.cp` matches; `timeout_query_list(now)` walks `first`, reaping past-due requests whose `--retries` is exhausted (`reinfo.re_timeouts++` + the per-`cinfo.flags` notify — ASYNC_CLIENT `sendto_iauth`+`ClearDNS`, ASYNC_CONNECT `sendto_flag` SCH_ERROR — then `rem_request`) or backing off the rest (`sentat=now`, `timeout` doubled, `resend_query`, `tout=now+timeout`), returning `(next>now)?next:now+AR_TTL`. A new `RES_RESEND_LINKAGE` seam de-statics the still-C `resend_query` (extern in res_link.o so the Rust `timeout_query_list` resolves to it; the cref oracle keeps it static — `cref_timeout_query_list` resolves to the objcopy-renamed local, self-contained since `resend_query` has no out-of-TU caller). Config-resolved: DEBUG off (`Debug`/`myctime` traces gone), USE_IAUTH on; `retries` is unsigned `char` on this platform → faithful `wrapping_sub`. Utility/callees (not in `msgtab`); still-C callers `s_bsd.c`/`ircd.c` + Rust `list.rs` resolve to the Rust defs at link. Gate: **L1 only** (`res_walk_diff`: two fully-isolated `World`s of fn-pointers + `first`/`last`/`reinfo` base pointers — del_queries head/middle/tail match + absent-cp no-op + all-match drain; timeout future-survive (min `tout`) / exhausted ASYNC_CONF·ASYNC_CLIENT (ClearDNS clears the DNS bit only)·ASYNC_CONNECT / retry back-off (resend=0 → `resend_query` no-op) / a mixed survivor+reaped+retried walk — return value, queue shape, `re_timeouts` all diffed; `timeofday` pinned, `adfd=-1` + BSS-zero `svchans` neutralize the variadic notifies, process LOCK serializes; zero diff over 9 tests). No L2/S2S (resolver inert under `NO_DNS_LOOKUP`, the queue never populates at runtime; `golden_s_dns` + `golden_registration` confirm the still-C resolver calls the Rust walkers without regression). **Still C in `res.c`:** only the answer parser + socket I/O half (`send_res_msg`/`do_query_*`/`query_name`/`resend_query`/`proc_answer`/`get_res`/`gethost_*`/`init_resolver`/`cres_mem`).
- **P6w DONE: `res.c` `bad_hostname`** (the pure RESTRICT_HOSTNAMES character validator used by the still-C answer parser `proc_answer`) — the next bottom-up leaf of the resolver proper, ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_HOSTNAME_P6w`; a new three-way `RES_HOSTNAME_LINKAGE` seam: `extern` in res_link.o so still-C `proc_answer` resolves to the Rust def, GLOBAL in the cref oracle under `-DRES_CACHE_EXPOSE` for `cref_bad_hostname`, static otherwise). Utility/callee (not in msgtab — called only from `proc_answer`). Faithful to the compiled body (`HOSTNAMES_UNDERSCORE` off): the for-increment-on-`continue` semantics + the `isalnum`/`s[1]` short-circuit ordering. Gate: L1 (`res_bad_hostname_diff`: a hostname corpus × every prefix length 0..=len+1, asserting identical return; valid names, hyphen/dot edge cases incl. the `len==1` trailing-hyphen guard, illegal chars space/`_`/`/`/`*`/`:`/control/high-bit, and the `len` boundary). No L2/S2S path (unreachable without the still-C answer parser).
- **P6x DONE: `res.c` `cres_mem`** (the DNS-cache memory-usage reporter, called from `s_debug.c`'s `count_memory` via `STATS z`) — the next bottom-up leaf of the resolver proper, ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_CRES_MEM_P6x`). Unlike the file-static cache/queue leaves, `cres_mem` is **exported** (res_ext.h) → the cref oracle already carries `cref_cres_mem`, so **no `RES_*_LINKAGE`/`*_EXPOSE` seam was needed** — the guard just drops the C body and the Rust def resolves it for `count_memory` at link. Utility/callee (not in `msgtab`). Faithful to the `nm += i - 1` **unsigned modular** arithmetic (0 aliases → `i==0` wraps −1, cancelled by the following `+= sizeof(char*)`; reproduced with `wrapping_add`) and the `%d`-on-`u_long` format quirk. Gates: L1 (`res_cres_mem_diff`: two-world return-value + RPL_STATSDEBUG sendQ byte diff over empty/0-alias-wrap/multi-alias/null-name/multi-entry caches — the per-entry summation the empty boot cache never exercises) + L2 (`golden_debug::stats_memory_match_reference`, STATS z, stays green). No S2S (oper STATS only, no `IsServer`/remote-field path).
- **P6y DONE: `res.c` `send_res_msg`** (the resolver UDP datagram-send leaf — the bottom of the send tree `do_query_*`/`resend_query`→`query_name`→`send_res_msg`) — ported to `ircd-common/res.rs` via `res_link.o` (`-DPORT_RES_SEND_P6y`; a new three-way `RES_SEND_LINKAGE` seam de-statics it: extern in res_link.o so the still-C `query_name` resolves the Rust def at link, GLOBAL in the cref oracle for `cref_send_res_msg`). Reads the Rust `ircd_res` (P6p) + the s_bsd.c `resfd` global; fans `msg[0..len]` to `max=MIN(nscount,rcount)` nameservers (clamped to 1 on `RES_PRIMARY`, floored to 1), bumping `reinfo.re_sent` only on a full-length `sendto`. Utility/callee (not in msgtab; only `query_name` calls it). Gate: L1 (`res_send_msg_diff`: two isolated `World`s each with own loopback `::1` UDP recv+send sockets; single-send / NULL-msg / rcount=0 floor / RES_PRIMARY override / two-nameserver / bad-resfd cases diffed on `{ret, datagram bytes, re_sent delta, family}`). No L2 (DNS path disabled project-wide via `NO_DNS_LOOKUP`; boot goldens stay byte-identical), no S2S.
- **P6z DONE: `res.c` `query_name`** (the DNS query builder/sender — the leaf above the P6y `send_res_msg`: `do_query_name`/`do_query_number`/`resend_query`/`get_res` call it) — ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_QUERY_P6z`; a new three-way `RES_QUERY_LINKAGE` seam de-statics it: extern in res_link.o so the still-C callers resolve the Rust def at link, GLOBAL in the cref oracle for `cref_query_name`). Builds the query into a `MAXPACKET` buffer via the Rust `ircd_res_mkquery` (P6o), picks a DNS id that doesn't collide with the outstanding-request queue (`do { nstmp = ntohs(hptr->id)+k + (tv.tv_usec & 0xffff); … } while (find_id(...))` — LRAND48 off → `gettimeofday`-seeded), records `id`/`sends++`/`sent` on the `ResRQ`, and fans the packet via `send_res_msg` (P6y); `r<=0` → `h_errno=NO_RECOVERY` return `r`, send `-1` → `h_errno=TRY_AGAIN` (with `sends` already bumped). Utility/callee (not in `msgtab`). Gate: L1 (`res_query_name_diff`: two isolated `World`s each with own loopback `::1` UDP recv+send sockets + `ircd_res`/`reinfo`/`resfd`/`first` base pointers; a **strong interposed `gettimeofday`** pins the id randomization so packets are byte-identical between worlds + the `find_id` collision loop is deterministic — A-record/PTR queries, a forced one-collision id advance vs the no-collision inverse, mkquery-failure NO_RECOVERY no-send, send-failure TRY_AGAIN with `sends` still bumped; diffed on `{ret, datagram bytes, rptr.{id,sends,sent}, re_sent delta, h_errno}`). No L2 (DNS path disabled project-wide via `NO_DNS_LOOKUP`; boot goldens `golden_registration`/`golden_s_dns` stay byte-identical — the still-C resolver calls the Rust `query_name`), no S2S. **Still C in `res.c`:** the answer parser + socket I/O (`do_query_name`/`do_query_number`/`resend_query`/`proc_answer`/`get_res`/`gethost_*`/`init_resolver`).
- **P6aa DONE: `res.c` `do_query_name`/`do_query_number` (the query-dispatch layer)** — the next bottom-up cluster of the resolver proper, above the Rust `query_name` (P6z) and below the still-C `gethost_*`/`get_res`/`resend_query` callers. `do_query_name` builds the forward-lookup hostname (truncate to `HOSTLEN`, append `ircd_res.defdname` on the dotless+`RES_DEFNAMES` resend path), `do_query_number` builds the reverse-lookup name (IPv4-mapped → `d.d.d.d.in-addr.arpa.`, else the 32-nibble `…ip6.arpa.` form); both allocate the `ResRQ` via `make_request` (P6u) when none was passed, then call the Rust `query_name` (P6z). Ported to `ircd-common/res.rs` via `res_link.o` (`-DPORT_RES_DOQUERY_P6aa`) + a new three-way `RES_DOQUERY_LINKAGE` (extern in res_link.o / GLOBAL in the cref oracle / static otherwise). Utility/callee leaf (not in `msgtab`), inert under `NO_DNS_LOOKUP` → **L1 is the gate** (`res_do_query_diff`, 7 tests, zero diff over a loopback UDP harness with `gettimeofday` interposed; fresh-vs-resend, domain-append vs already-dotted, overlong-defdname `-1`, all three reverse-name arms, resend no-alloc). No L2/S2S (no `IsServer`/remote-field path; `golden_s_dns`+`golden_registration` stay green).
- **P6bb DONE: `res.c` `gethost_byname_type`/`gethost_byname`/`gethost_byaddr`** (the public host-lookup entry points, the layer above the cache lookup + query dispatch) — ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_GETHOST_P6bb`). **No linkage seam** — they are exported `res_ext.h` symbols, so the `cref_*` oracle already exists (like P6x `cres_mem`). Each bumps a lookup counter (`re_na_look`/`re_nu_look`), consults the Rust cache (`find_cache_name`/`find_cache_number`), and on a miss fires the Rust `do_query_name`/`do_query_number` when `lp != NULL` (else returns NULL). `gethost_byaddr`'s only caller (`s_bsd.c`) is gated behind `NO_DNS_LOOKUP`'s `#else` → compiled out of the locked binary (ported + L1-verified regardless). Utility/leaf — none in `msgtab` → **L1 only**. L1 (`res_gethost_diff`, 8 cases): two isolated cache+query worlds (live vs cref) over the cache globals + resolver-query globals, each with a loopback `::1` UDP recv socket + pinned `gettimeofday`; branch matrix + inverses (bad-type early-out, cache HIT vs MISS, `lp==NULL` short-circuit vs `lp!=NULL` AAAA/PTR query issue, byname→T_AAAA delegation, `re_na_look` vs `re_nu_look` split). No S2S (resolver is inert under `NO_DNS_LOOKUP`; no IsServer/remote-field path).
- **P6cc DONE: `res.c` `resend_query`** (the DNS request-retry dispatcher) — ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_RESEND_P6cc`); the next bottom-up unit above the P6aa query-dispatch layer (`do_query_name`/`do_query_number`) and below the still-C `get_res`. Upstream file-static → the P6v `RES_RESEND_LINKAGE` seam promoted to the standard three-way shape (`extern` in res_link.o, GLOBAL in the cref oracle → `cref_resend_query` for L1, else static). A no-op when `resend==0`, else bumps `reinfo.re_resends` and re-dispatches by record type (`T_PTR`→`do_query_number`, `T_A`/`T_AAAA`→`do_query_name`, default→no-op). Utility/callee (file-static, not in msgtab; callers = Rust `timeout_query_list` + still-C `get_res`). L1 gate (`res_resend_query_diff`: two isolated cache+query worlds over a loopback UDP harness with `gettimeofday` pinned; matrix = `resend==0` no-op / `T_A` dispatch / `T_PTR` dispatch / default-arm counter-only). No L2 (resolver is dead code under `NO_DNS_LOOKUP`). No S2S. **Still C in res.c:** only `proc_answer`/`get_res`/`init_resolver`.
- **P6dd DONE: `res.c` `proc_answer`** (the DNS answer-section parser — fills `rptr->he` from a nameserver datagram) — ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_PROC_ANSWER_P6dd`; a new three-way `RES_PROC_ANSWER_LINKAGE` de-statics the upstream file-static fn for the Rust def + the cref oracle `cref_proc_answer`). Walks the answer section (skip questions via `__ircd_dn_skipname`+QFIXEDSZ; per answer expand name + read type/class/ttl/dlen, optional `RES_DEFNAMES` defdname append, wrong-type skip, A/AAAA→v4-mapped addr slot, PTR→validate+`find_cache_name` flag fixup, CNAME→alias) using the already-Rust `ircd_dn_expand`/`ircd_getshort`/`ircd_getlong` (P6n), `bad_hostname` (P6w), `find_cache_name` (P6s), `MyMalloc` (P2) + the still-C variadic `sendto_flag`; the res.c-private scratch `hostbuf` moved into Rust with it. Utility/callee (file-static, sole caller the still-C `get_res`); **L1 is the gate**, no L2 path (resolver dead-code under `NO_DNS_LOOKUP`), no S2S. L1 (`res_proc_answer_diff`: 12 cases over two isolated worlds parsing constructed DNS reply buffers — single A/AAAA, multi-A dedup, good vs bad-hostname PTR, CNAME-then-A, wrong-type skip, bad-IP-len -2, RES_DEFNAMES dotless-append vs dotted-untouched, two-question skip, empty answers). **Only `get_res`/`init_resolver` (socket I/O) remain C in `res.c`.**
- **P6ee DONE: `res.c` `init_resolver`** (the bit-flag resolver bootstrap — `RES_INITLIST`/`RES_CALLINIT`/`RES_INITSOCK`/`RES_INITCACH` + bare `op==0`) — ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_INIT_P6ee`; exported `res_ext.h` symbol → `cref_init_resolver` already exists, **no** linkage seam). Under the locked config LRAND48/DEBUG are off so the `srand48` line + `RES_INITDEBG` block drop out. Still-C I/O callers (`s_bsd.c` rehash / `ircd.c` boot) resolve to the Rust def at link. Utility/callee (no `msgtab` entry; no client path → L1 is the gate). L1 (`res_init_resolver_diff`: isolated-worlds vs `cref_` per op flag — INITLIST zeroes reinfo+nulls queue, INITCACH zeroes cainfo+hashtable, CALLINIT diffs `ircd_res` masking the random `.id` incl. the `nscount==0` ::1-fallback, INITSOCK asserts return==resfd>=0 + AF_INET6 socket, op==0 returns resfd). No S2S. **Only `get_res` (recvfrom answer driver) remains C in res.c.**
- **P6ff DONE: `res.c` `get_res` — the LAST C *function* in res.c** (the recvfrom DNS answer driver) — ported to `ircd-common/res.rs` via the `res_link.o` partial port (`-DPORT_RES_GET_RES_P6ff`; exported `res_ext.h` symbol → `cref_get_res` already exists, **no** linkage seam). Reads one nameserver datagram off `resfd`, ntohs the header, `find_id`s the request, anti‑spoofs the source against `ircd_res.nsaddr_list`, branches on rcode (NOERROR/NXDOMAIN/SERVFAIL→TRY_AGAIN, NOERROR+ancount0→NO_DATA, else NO_RECOVERY), parses via the Rust `proc_answer`, then `make_cache`s an A/AAAA result / PTR‑relookups via `gethost_byname_type` / retries via `resend_query` — all callees already Rust. `getres_err` factored to an early‑return helper. Utility/callee (no `msgtab` entry; sole caller is the still‑C `s_bsd.c` io‑loop, inert under `NO_DNS_LOOKUP` → L1 is the gate). L1 (`res_get_res_diff`: two isolated loopback‑UDP worlds — `resfd` recv socket + an `::1` ns socket that sends the crafted reply *and* captures follow‑ups — with a fixed `gettimeofday`; diffed `{ret, hostent, reinfo deltas, incache, ca_adds, request‑gone, h_errno, follow‑up bytes}` across A‑success/unknown‑id/short‑packet/NXDOMAIN/SERVFAIL/REFUSED/NO_DATA/anti‑spoof/PTR‑relookup). **`res.c` now has NO C functions left** — `res_link.o` defines only the resolver data globals; the final `res.o` drop is the last P6 res step. No S2S.
- **P6gg DONE: `res.c` data globals → Rust + the final `res.o` drop** (`reinfo`/`cachetop`/`cainfo`/`hashtable`/`incache`/`first`/`last` — the resolver's private data globals, the last C remnant after P6ff left `res.c` with no functions) — moved into `ircd-common/res.rs` as `#[no_mangle] pub static mut` definitions (`null_mut()`/`0`/`MaybeUninit::zeroed()` reproduce C BSS), so `res.o` is added to `PORTED` and **dropped outright** (no more `res_link.o`; the long `-DPORT_RES_*` second-compile is gone). **`res.c` is now FULLY Rust.** The cref oracle keeps the full unguarded `res.o` (`-DRES_CACHE_EXPOSE`) so the 19 `res_*_diff` L1 tests still resolve `cref_*`. Data-global move (no new function) → no new L1 test; gate is the existing res L1 suite (all 19, 130 assertions) still zero-diff with the live-world globals now resolving to the Rust storage, + clean build (0 warnings) + `golden_registration`/`golden_s_dns` byte-identical. No L2 resolver path (dead-code under `NO_DNS_LOOKUP`), no S2S.
