Initial commit: C++20 SECS-II / HSMS / GEM client + server

A fully containerised SECS/GEM toolchain. Single docker compose project,
no host build tools. 63 unit-test cases / 278 assertions, two demo
executables, end-to-end two-container demo exercising every implemented
capability.

Architecture (bottom-up):

  secs2/   E5 SECS-II codec
    Item        variant over L/A/B/BOOLEAN/I1-8/U1-8/F4/F8
    encode/decode  big-endian, 1/2/3-byte length encoding
    Message     SxFy + W-bit + optional root item
    to_sml      human-readable text rendering

  hsms/    E37 HSMS transport (TCP)
    Header      10-byte header + SType enum (Data/Select/Deselect/
                Linktest/Reject/Separate)
    Frame       4-byte length prefix + payload encode/decode
    Connection  async Asio TCP, NOT-SELECTED -> SELECTED state machine,
                T3/T5/T6/T7/T8 timers, system-bytes reply correlation,
                graceful close-after-flush separation

  endpoint  active Client (connect with T5 retry) and passive Server
            (accept loop) wrappers over Connection

  gem/     E30 GEM logic
    ControlStateMachine  5-state E30 control model with operator
                         actions, host requests, SEMI-mandated ack
                         codes (OnlineAck, OfflineAck, CommAck), and
                         a state-change handler
    EquipmentDataModel   in-memory dictionary: SVIDs, DVIDs, ECIDs
                         (with EAC), CEIDs, report defs, CEID->report
                         links, enabled-events set, alarm table
                         (ALCD, enabled, active), process programs,
                         host command registry, clock (16-char
                         YYYYMMDDhhmmsscc with offset)
    messages.hpp         builders + parsers for every SxFy below

GEM message coverage (full list):

  S1F1/F2    Are You There / On Line Data
  S1F3/F4    Selected Equipment Status Request / Data
  S1F11/F12  Status Variable Namelist Request / Data
  S1F13/F14  Establish Communications (+ CommAck)
  S1F15/F16  Request OFFLINE (+ OfflineAck)
  S1F17/F18  Request ONLINE (+ OnlineAck)
  S2F13/F14  Equipment Constant Request / Data
  S2F15/F16  EC Send + EquipmentAck (Accept/UnknownEcid/Busy/OutOfRange)
  S2F17/F18  Date and Time Request / Data
  S2F29/F30  Equipment Constant Namelist Request / Data
  S2F31/F32  Date and Time Set Request / TimeAck
  S2F33/F34  Define Report + DefineReportAck (5 enum values)
  S2F35/F36  Link Event Report + LinkEventAck
  S2F37/F38  Enable / Disable Event Report + EnableEventAck
  S2F41/F42  Host Command + HostCmdAck (7 values) + per-param CPACKs
  S5F1/F2    Alarm Report Send + AlarmAck (ALCD bit-7 set/cleared
             + lower-7 category)
  S5F3/F4    Enable/Disable Alarm Send + AlarmAck
  S5F5/F6    List Alarms Request / Data (active alarms tagged in ALCD)
  S6F11/F12  Event Report Send (equipment-initiated CEID emission
             with full report data) + EventReportAck
  S7F3/F4    Process Program Send + ProcessProgramAck (7 values)
  S7F5/F6    Process Program Request / Data
  S7F19/F20  Current EPPD List Request / Data
  S10F1/F2   Terminal Display Single (host->equipment) + TerminalAck
  S10F3/F4   Terminal Display Single (equipment->host)

Demo apps:

  apps/secs_server.cpp   passive equipment. Populates the data model
                         with 3 SVIDs (ControlState, Clock,
                         EventsEnabled), 2 ECIDs, 3 CEIDs
                         (ControlStateChanged, AlarmSetEvent,
                         ProcessStarted), 2 alarms (Chiller Temp High
                         cat 4, Door Open cat 1), 2 recipes
                         (RECIPE-A, RECIPE-B), and 4 host commands
                         (START, STOP, PAUSE, FAULT). Emits S6F11 on
                         every control state transition + on START;
                         emits S5F1 + the AlarmSetEvent CEID on FAULT.
                         Pushes an S10F3 welcome message when the host
                         comes online.

  apps/secs_client.cpp   active host. Walks 17 steps: Establish ->
                         Online -> S1F11 SVID namelist -> S1F3 read ->
                         S2F29 EC namelist -> S2F13 read ->
                         S2F17 clock -> S2F33/S2F35/S2F37 dynamic
                         event subscription -> S2F41 START
                         (-> receives S6F11) -> S5F5 alarm list ->
                         S5F3 enable alarm 1 -> S2F41 FAULT
                         (-> receives S5F1 + S6F11) -> S7F19/S7F5
                         recipe list + body -> S10F1 terminal ->
                         S1F15 Offline -> Separate. Handles inbound
                         S6F11, S5F1, S10F3 primaries.

Testing:

  tests/test_secs2.cpp         codec round-trip for every format,
                               byte-layout assertions for known values,
                               truncation/trailing-byte rejection,
                               nested list round-trip, SML rendering
  tests/test_hsms.cpp          header byte layout, data + control
                               header round-trip, full frame round-
                               trip with length prefix, short-payload
                               rejection
  tests/test_control_state.cpp every (state, event) pair in the E30
                               control state machine, including
                               AlreadyOnline / NotAccept rejections
                               and idempotent offline-while-offline
  tests/test_data_model.cpp    SVID/ECID/Alarm/Recipe CRUD, clock
                               format + parse, host command registry,
                               full event-report pipeline (define ->
                               link -> enable -> compose) with
                               every error path (InvalidVid,
                               UnknownCeid, UnknownRptid), alarm
                               set/clear with ALCD bit-7 semantics
  tests/test_messages.cpp      round-trip + byte-layout for every
                               builder/parser pair, including S6F11
                               event reports with mixed item types

Toolchain:

  Dockerfile          Ubuntu 24.04, g++-13, CMake, Ninja, libasio-dev
  docker-compose.yml  builder / tests / server / client services,
                      source bind-mounted, build artifacts in a
                      named volume so the host tree stays clean
  CMakeLists.txt      C++20, -Wall -Wextra -Wpedantic, standalone
                      Asio (ASIO_STANDALONE), doctest via FetchContent

Documentation:

  README.md           architecture, quick start, demo log
  COMPLIANCE.md       honest per-capability E5/E30/E37 audit with
                      spec section refs. Calls out what's implemented,
                      what's partial (Reject.req, Alarms missing F7/F8,
                      EC range validation, PP without verify, terminal
                      single-line only), and what's intentionally not
                      yet implemented (spooling, S9 error stream,
                      Documentation S1F19/F20+F21/F22, limits monitoring,
                      trace data collection, multi-block, material
                      movement). Does NOT claim "100% GEM-compliant" and
                      lists the work required to honestly make that claim.

This is Layer 0 + the start of Layer 1 from implementation_plan.md.
The transition-table-driven "spec-as-data" architecture (Layer 1
proper) is not yet implemented; the current code uses imperative
state machines that are structurally ready to be refactored onto
tables.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
This commit is contained in:
2026-06-02 00:21:10 +02:00
commit 96b02f8b50
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#include "secsgem/hsms/connection.hpp"
#include <exception>
namespace secsgem::hsms {
namespace {
class HsmsCategory : public std::error_category {
public:
const char* name() const noexcept override { return "hsms"; }
std::string message(int ev) const override {
switch (static_cast<Error>(ev)) {
case Error::Timeout: return "HSMS transaction timeout";
case Error::Closed: return "HSMS connection closed";
}
return "unknown HSMS error";
}
};
const HsmsCategory g_category;
constexpr std::size_t kMaxFrameLength = 16 * 1024 * 1024;
} // namespace
std::error_code make_error(Error e) {
return {static_cast<int>(e), g_category};
}
Connection::Connection(asio::ip::tcp::socket socket, Mode mode, uint16_t device_id,
Timers timers)
: socket_(std::move(socket)),
t6_timer_(socket_.get_executor()),
t7_timer_(socket_.get_executor()),
t8_timer_(socket_.get_executor()),
linktest_timer_(socket_.get_executor()),
mode_(mode),
device_id_(device_id),
timers_(timers) {}
void Connection::start() {
read_length();
if (mode_ == Mode::Active) {
send_select_req();
} else {
arm_t7();
}
}
// --- read path ------------------------------------------------------------
void Connection::read_length() {
if (closed_) return;
auto self = shared_from_this();
asio::async_read(socket_, asio::buffer(len_buf_),
[this, self](std::error_code ec, std::size_t n) { on_length(ec, n); });
}
void Connection::on_length(std::error_code ec, std::size_t) {
if (closed_) return;
if (ec) {
close("read length: " + ec.message());
return;
}
const uint32_t len = (static_cast<uint32_t>(len_buf_[0]) << 24) |
(static_cast<uint32_t>(len_buf_[1]) << 16) |
(static_cast<uint32_t>(len_buf_[2]) << 8) |
static_cast<uint32_t>(len_buf_[3]);
if (len < kHeaderSize) {
close("invalid frame length " + std::to_string(len));
return;
}
if (len > kMaxFrameLength) {
close("frame too large: " + std::to_string(len));
return;
}
payload_.resize(len);
t8_timer_.expires_after(timers_.t8);
auto self = shared_from_this();
t8_timer_.async_wait([this, self](std::error_code tec) {
if (!tec && !closed_) close("T8 intercharacter timeout");
});
asio::async_read(socket_, asio::buffer(payload_),
[this, self](std::error_code rec, std::size_t n) { on_payload(rec, n); });
}
void Connection::on_payload(std::error_code ec, std::size_t) {
if (closed_) return;
t8_timer_.cancel();
if (ec) {
close("read payload: " + ec.message());
return;
}
try {
handle_frame(Frame::decode(payload_.data(), payload_.size()));
} catch (const std::exception& e) {
close(std::string("decode: ") + e.what());
return;
}
read_length();
}
void Connection::handle_frame(Frame frame) {
if (frame.header.stype == SType::Data) {
handle_data(frame);
} else {
handle_control(frame);
}
}
void Connection::handle_data(const Frame& frame) {
const Header& h = frame.header;
// Reply correlation: an even function with matching system bytes completes an
// outstanding request.
auto it = pending_requests_.find(h.system_bytes);
if ((h.function() % 2 == 0) && it != pending_requests_.end()) {
secs2::Message reply;
try {
reply = secs2::Message::from_body(h.stream(), h.function(), h.w_bit(), frame.body);
} catch (const std::exception& e) {
close(std::string("reply body decode: ") + e.what());
return;
}
auto cb = std::move(it->second.cb);
it->second.t3->cancel();
pending_requests_.erase(it);
log("<- " + h.describe());
cb({}, reply);
return;
}
// Primary message; only valid while SELECTED.
if (state_ != State::Selected) {
send_frame(Frame(Header::control(SType::RejectReq, h.system_bytes, kControlSessionId,
static_cast<uint8_t>(SType::Data),
static_cast<uint8_t>(RejectReason::EntityNotSelected))));
return;
}
secs2::Message msg;
try {
msg = secs2::Message::from_body(h.stream(), h.function(), h.w_bit(), frame.body);
} catch (const std::exception& e) {
close(std::string("message body decode: ") + e.what());
return;
}
log("<- " + h.describe());
if (!on_message_) return;
auto reply = on_message_(msg);
if (reply) {
Frame out(Header::data_message(device_id_, reply->stream, reply->function,
reply->reply_expected, h.system_bytes),
reply->encode_body());
log("-> " + out.header.describe());
send_frame(std::move(out));
}
}
void Connection::handle_control(const Frame& frame) {
const Header& h = frame.header;
switch (h.stype) {
case SType::SelectReq: {
log("<- Select.req");
send_frame(Frame(Header::control(SType::SelectRsp, h.system_bytes, h.session_id, 0,
static_cast<uint8_t>(SelectStatus::Ok))));
log("-> Select.rsp (Ok)");
enter_selected();
break;
}
case SType::SelectRsp: {
if (pending_control_ && pending_control_->expected_response == SType::SelectRsp &&
pending_control_->system_bytes == h.system_bytes) {
clear_control_transaction();
if (h.byte3 == static_cast<uint8_t>(SelectStatus::Ok)) {
log("<- Select.rsp (Ok)");
enter_selected();
} else {
close("Select rejected, status=" + std::to_string(h.byte3));
}
}
break;
}
case SType::DeselectReq: {
log("<- Deselect.req");
send_frame(Frame(Header::control(SType::DeselectRsp, h.system_bytes, h.session_id, 0,
static_cast<uint8_t>(DeselectStatus::Ok))));
state_ = State::NotSelected;
arm_t7();
break;
}
case SType::DeselectRsp: {
if (pending_control_ && pending_control_->expected_response == SType::DeselectRsp &&
pending_control_->system_bytes == h.system_bytes) {
clear_control_transaction();
state_ = State::NotSelected;
}
break;
}
case SType::LinktestReq: {
send_frame(Frame(Header::control(SType::LinktestRsp, h.system_bytes)));
break;
}
case SType::LinktestRsp: {
if (pending_control_ && pending_control_->expected_response == SType::LinktestRsp &&
pending_control_->system_bytes == h.system_bytes) {
clear_control_transaction();
arm_linktest();
}
break;
}
case SType::SeparateReq: {
log("<- Separate.req");
close("peer separated");
break;
}
case SType::RejectReq: {
log("<- Reject.req reason=" + std::to_string(h.byte3));
break;
}
case SType::Data:
break; // unreachable
}
}
// --- write path -----------------------------------------------------------
void Connection::send_frame(Frame frame) {
if (closed_) return;
write_queue_.push_back(frame.encode());
if (!writing_) write_next();
}
void Connection::write_next() {
if (write_queue_.empty()) {
writing_ = false;
if (close_after_flush_) close(close_reason_);
return;
}
writing_ = true;
auto self = shared_from_this();
asio::async_write(socket_, asio::buffer(write_queue_.front()),
[this, self](std::error_code ec, std::size_t) {
write_queue_.pop_front();
if (ec) {
close("write: " + ec.message());
return;
}
write_next();
});
}
// --- public send API ------------------------------------------------------
void Connection::send_request(secs2::Message msg, ReplyHandler cb) {
if (closed_) {
cb(make_error(Error::Closed), {});
return;
}
const uint32_t sys = next_system_bytes();
Frame f(Header::data_message(device_id_, msg.stream, msg.function, true, sys),
msg.encode_body());
auto t3 = std::make_shared<asio::steady_timer>(socket_.get_executor());
t3->expires_after(timers_.t3);
pending_requests_.emplace(sys, PendingRequest{std::move(cb), t3});
auto self = shared_from_this();
t3->async_wait([this, self, sys](std::error_code ec) {
if (ec) return;
auto it = pending_requests_.find(sys);
if (it == pending_requests_.end()) return;
auto cb2 = std::move(it->second.cb);
pending_requests_.erase(it);
cb2(make_error(Error::Timeout), {});
});
log("-> " + f.header.describe());
send_frame(std::move(f));
}
void Connection::send_data(secs2::Message msg) {
if (closed_) return;
const uint32_t sys = next_system_bytes();
Frame f(Header::data_message(device_id_, msg.stream, msg.function, msg.reply_expected, sys),
msg.encode_body());
log("-> " + f.header.describe());
send_frame(std::move(f));
}
void Connection::separate() {
if (closed_) return;
Frame f(Header::control(SType::SeparateReq, next_system_bytes(), device_id_));
log("-> Separate.req");
close_after_flush_ = true;
close_reason_ = "separated";
send_frame(std::move(f));
}
void Connection::close(const std::string& reason) {
if (closed_) return;
closed_ = true;
std::error_code ignore;
t6_timer_.cancel();
t7_timer_.cancel();
t8_timer_.cancel();
linktest_timer_.cancel();
socket_.shutdown(asio::ip::tcp::socket::shutdown_both, ignore);
socket_.close(ignore);
for (auto& [sys, pr] : pending_requests_) {
pr.t3->cancel();
pr.cb(make_error(Error::Closed), {});
}
pending_requests_.clear();
log("xx CLOSED: " + reason);
if (on_closed_) on_closed_(reason);
}
// --- handshakes & timers --------------------------------------------------
void Connection::send_select_req() {
const uint32_t sys = next_system_bytes();
log("-> Select.req");
send_frame(Frame(Header::control(SType::SelectReq, sys)));
start_control_transaction(SType::SelectRsp, sys, "Select");
}
void Connection::send_linktest_req() {
const uint32_t sys = next_system_bytes();
send_frame(Frame(Header::control(SType::LinktestReq, sys)));
start_control_transaction(SType::LinktestRsp, sys, "Linktest");
}
void Connection::enter_selected() {
if (state_ == State::Selected) return;
state_ = State::Selected;
t7_timer_.cancel();
log("== SELECTED ==");
arm_linktest();
if (on_selected_) on_selected_();
}
void Connection::arm_t7() {
if (mode_ != Mode::Passive) return;
if (timers_.t7.count() <= 0) return;
t7_timer_.expires_after(timers_.t7);
auto self = shared_from_this();
t7_timer_.async_wait([this, self](std::error_code ec) {
if (!ec && !closed_ && state_ == State::NotSelected) close("T7 not-selected timeout");
});
}
void Connection::arm_linktest() {
if (timers_.linktest.count() <= 0) return;
if (state_ != State::Selected) return;
linktest_timer_.expires_after(timers_.linktest);
auto self = shared_from_this();
linktest_timer_.async_wait([this, self](std::error_code ec) {
if (!ec && !closed_ && state_ == State::Selected) send_linktest_req();
});
}
void Connection::start_control_transaction(SType expected_response, uint32_t system_bytes,
const char* what) {
pending_control_ = PendingControl{expected_response, system_bytes};
t6_timer_.expires_after(timers_.t6);
auto self = shared_from_this();
std::string what_str = what;
t6_timer_.async_wait([this, self, what_str](std::error_code ec) {
if (!ec && !closed_ && pending_control_) close("T6 timeout on " + what_str);
});
}
void Connection::clear_control_transaction() {
pending_control_.reset();
t6_timer_.cancel();
}
uint32_t Connection::next_system_bytes() {
uint32_t s = next_system_bytes_++;
if (next_system_bytes_ == 0) next_system_bytes_ = 1;
return s;
}
void Connection::log(const std::string& msg) {
if (on_log_) on_log_(msg);
}
} // namespace secsgem::hsms