feat: v2.2.0 — Discovery (§Phase 13 milestone 46)

.fusa-reqs.json

@@ -2927,6 +2927,78 @@
       "standard": "iso26262",
       "level": "ASIL-B",
       "asil": "ASIL-B"
+    },
+    {
+      "id": "REQ-DISC-001",
+      "title": "Discovery request framing \u2014 byte_bus_id 0, register-map address 0",
+      "text": "rcp::discovery::make_discovery_request shall build an unconditional ACF_ABB read (op=false) targeting byte_bus_id 0 (kDiscoveryByteBusId), and kDiscoveryRegisterAddress shall be 0, fixing discovery reads at the general bootstrap/magic-number register-map region.",
+      "standard": "iso26262",
+      "level": "ASIL-B",
+      "asil": "ASIL-B"
+    },
+    {
+      "id": "REQ-DISC-002",
+      "title": "Discovery is NTSCF-only; a TSCF-headed discovery request is dropped",
+      "text": "rcp::discovery::encode_discovery_request shall always produce an NTSCF-headed frame, and rcp::discovery::decode_discovery_request shall return DiscoveryErrc::tscf_headed_request_dropped without decoding further when given a frame whose AVTPDU subtype byte is TSCF.",
+      "standard": "iso26262",
+      "level": "ASIL-B",
+      "asil": "ASIL-B"
+    },
+    {
+      "id": "REQ-DISC-003",
+      "title": "The first discovery request claims the discovery stream",
+      "text": "DiscoveryClaim::on_discovery_request shall return ClaimOutcome::Claimed and record `client` as the claim holder when no active claim currently exists and server_state is HwUnconfigured or HwConfigured.",
+      "standard": "iso26262",
+      "level": "ASIL-B",
+      "asil": "ASIL-B"
+    },
+    {
+      "id": "REQ-DISC-004",
+      "title": "The discovery claim lapses after Discovery_TimeOut",
+      "text": "DiscoveryClaim shall treat a claim as lapsed once (now - claimed_at) is at least Discovery_TimeOut (kDefaultTimeout, ~20ms by default), after which may_configure shall return false for the prior holder and a subsequent discovery request from any client shall be able to claim the stream anew.",
+      "standard": "iso26262",
+      "level": "ASIL-B",
+      "asil": "ASIL-B"
+    },
+    {
+      "id": "REQ-DISC-005",
+      "title": "A claim does not block concurrent discovery reads from other clients",
+      "text": "DiscoveryClaim::on_discovery_request from a client other than the active holder shall return ClaimOutcome::HeldByOther without altering the existing claim, and shall never affect whether that client's underlying discovery read is answered; the same holder re-requesting before the claim lapses shall return ClaimOutcome::AlreadyHeld.",
+      "standard": "iso26262",
+      "level": "ASIL-B",
+      "asil": "ASIL-B"
+    },
+    {
+      "id": "REQ-DISC-006",
+      "title": "Only the active claim holder may issue a configuration request",
+      "text": "DiscoveryClaim::on_configuration_request shall return true and consume (release) the claim only when called by the client currently holding an active, unlapsed claim; a call from any other client shall return false and shall leave an existing other-held claim untouched.",
+      "standard": "iso26262",
+      "level": "ASIL-B",
+      "asil": "ASIL-B"
+    },
+    {
+      "id": "REQ-DISC-007",
+      "title": "Discovery-stream claiming is scoped to HW_UNCONFIGURED/HW_CONFIGURED",
+      "text": "DiscoveryClaim::on_discovery_request shall return ClaimOutcome::NotEligible and leave any existing claim state unchanged whenever server_state is RcpConfigured.",
+      "standard": "iso26262",
+      "level": "ASIL-B",
+      "asil": "ASIL-B"
+    },
+    {
+      "id": "REQ-DISC-008",
+      "title": "DiscoveryErrc is a distinct error category with non-empty messages",
+      "text": "rcp::discovery::make_error_code(DiscoveryErrc::tscf_headed_request_dropped) shall report rcp::discovery::discovery_category() as its category and shall have a non-empty diagnostic message.",
+      "standard": "iso26262",
+      "level": "ASIL-B",
+      "asil": "ASIL-B"
+    },
+    {
+      "id": "REQ-DISC-009",
+      "title": "A server answers discovery in every lifecycle state",
+      "text": "rcp::discovery::should_answer_discovery shall return true for HwUnconfigured, HwConfigured, and RcpConfigured alike, reflecting the mandatory-baseline requirement that discovery is answered regardless of lifecycle state.",
+      "standard": "iso26262",
+      "level": "ASIL-B",
+      "asil": "ASIL-B"
     }
   ]
 }

CMakeLists.txt

@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.21)
 
 project(cpp-rcp
-    VERSION 2.1.0
+    VERSION 2.2.0
     DESCRIPTION "Remote Control Protocol for automotive zonal architecture (C++)"
     HOMEPAGE_URL "https://github.com/SoundMatt/cpp-RCP"
     LANGUAGES CXX

ROADMAP.md

@@ -266,6 +266,34 @@ onward); see the header comment in `rcp.hpp` and the disposition table.
 
 ### 46. Discovery (v2.2.0)
 
+**Done (v2.2.0):** `rcp/discovery.hpp` implements the discovery mechanism
+described below on top of the three prior milestones without changing any
+of them. `make_discovery_request`/`encode_discovery_request` build an
+unconditional ACF_ABB read targeting `byte_bus_id 0` (`kDiscoveryByteBusId`,
+matching `regmap::kEp0`) at register-map address 0 (`kDiscoveryRegisterAddress`
+— the general bootstrap/magic-number field region `rcp/regmap.hpp` already
+models), always wrapped in an NTSCF header, riding directly on `rcp/wire.hpp`'s
+existing framing with no changes to that codec. `decode_discovery_request`
+enforces the NTSCF-only rule by returning
+`DiscoveryErrc::tscf_headed_request_dropped` — modeled as a decode failure,
+not a flag a caller could forget to check — for any TSCF-headed frame.
+`DiscoveryClaim` implements discovery-stream claiming: the first discovery
+request accepted while `rcp::lifecycle::ServerLifecycle` reports
+`HwUnconfigured`/`HwConfigured` reserves the stream for that client's
+configuration writes (`ClaimOutcome::Claimed`); the reservation lapses after
+a configurable `Discovery_TimeOut` (`kDefaultTimeout`, ~20 ms default) if no
+configuration request follows (`on_configuration_request` returning `false`
+once lapsed, freeing the stream for the next claimant); other clients'
+concurrent discovery requests are reported as `HeldByOther`/`AlreadyHeld`
+without ever touching whether their own reads get answered, since claiming
+and read-answering are deliberately independent concerns in this
+implementation; and a request in `RcpConfigured` is always `NotEligible`,
+since the claiming mechanism itself is scoped to the two pre-RCP-configured
+states. `should_answer_discovery` is a trivial always-true function over
+`ServerState` — a deliberate, testable single call site documenting the
+any-state answering invariant rather than an implicit assumption. New
+coverage lives in `tests/test_discovery.cpp` (REQ-DISC-001..009).
+
 - Implement the discovery request: a broadcastable ACF_ABB read addressed
   to `byte_bus_id 0`, NTSCF-only (a TSCF-headed discovery request is
   dropped), reading from register-map address 0 (extraction §3.5)