- decnet/prober/osfp/p0f/provider.py: P0fV2Provider loads the four
vendored .fp files into per-context signature lists (syn / synack /
rst / stray) and matches via highest-specificity score across the
relevant list. Also auto-picks up p0f-decnet.fp if present (GPL-3.0
additions land there later, empty for now).
- decnet/prober/osfp/factory.py: get_provider / get_all_providers /
reset_cache, mirrors decnet/geoip/factory exactly. Env-dispatched
via DECNET_OSFP_PROVIDERS (default "p0f-v2"). Reserved names
"nmap-osdb" (pending Fyodor's grant) and "decnet-observed" (our
future curated DB) raise NotImplementedError — visible on the
factory surface so a typo doesn't silently fall through.
- decnet/prober/osfp/__init__.py now re-exports the public API so
callers use `from decnet.prober.osfp import get_provider` without
reaching into submodules (upholds the provider-subpackage rule).
15 new provider+factory tests covering:
- All four DB contexts load (262/61/46/6 sigs per inventory).
- Known-good Linux 2.6 SYN + Linux 2.2 SYN-ACK match end-to-end.
- Unknown observations / contexts return None, not raise.
- Factory memoises, env override honoured, unsupported names raise.
- Reserved names raise NotImplementedError (not silent None).
`sniffer_rollup` wiring lands in the next commit.
First code layer of the OS-fingerprinting work on top of yesterday's
vendored p0f v2 database. Three new modules, all pure (no I/O outside
of the parser's file read):
- decnet/prober/osfp/base.py — Provider protocol + OsMatch dataclass
matching the established Provider convention in decnet/geoip and
decnet/bus. Docstring spells out the never-raise invariant: malformed
input returns None, so a single bad event can't wedge a whole
attacker-profile rebuild.
- decnet/prober/osfp/p0f/signature.py — Signature dataclass + three
predicate helpers (WindowSpec / IntSpec / OptionToken) encoding the
p0f v2 DSL's wildcard / modulo / MSS-multiple / MTU-multiple
semantics. Scoring is our extension on top of upstream p0f's
first-match-wins policy: each signature carries a precomputed
specificity in [0, 1] so the factory can pick the most-specific
match when multiple signatures fire against one observation.
- decnet/prober/osfp/p0f/format.py — .fp line parser. Every shipped
field variant from the DSL spec at the top of p0f.fp is covered
(Snn / Tnn / %nnn / * for window; T0 vs T; -/@/* os-genre prefixes;
quirks as concatenated single-letter flags; '.' sentinels for
no-options / no-quirks). Malformed lines log a warning and skip
instead of aborting the whole file — 1 bad row must not cost the
other 374.
20 parser tests + 14 scoring tests. Full vendored-DB smoke tests
confirm all 375 signatures parse round-trip (262 SYN + 61 SYN-ACK +
46 RST + 6 stray) and every computed specificity lands in [0, 1].
