API mission

src/mission/modbus_trigger_service.cpp

@@ -0,0 +1,156 @@
+#include "mission/modbus_trigger_service.hpp"
+
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include <cstring>
+#include <vector>
+
+namespace lm {
+
+namespace {
+
+constexpr int kMinCoilId = 1001;
+constexpr int kMaxCoilId = 2000;
+
+bool coilIdValid(int coil_id)
+{
+  return coil_id >= kMinCoilId && coil_id <= kMaxCoilId;
+}
+
+int modbusAddressToCoilId(uint16_t address)
+{
+  return static_cast<int>(address);
+}
+
+}  // namespace
+
+ModbusTriggerService::ModbusTriggerService(MissionStore& store, EnqueueFn enqueue_fn, int tcp_port)
+    : store_(store), enqueue_fn_(std::move(enqueue_fn)), tcp_port_(tcp_port)
+{
+  tcp_thread_ = std::thread([this] { tcpLoop(); });
+}
+
+ModbusTriggerService::~ModbusTriggerService()
+{
+  stop_ = true;
+  if (tcp_thread_.joinable())
+    tcp_thread_.join();
+}
+
+nlohmann::json ModbusTriggerService::coilStates() const
+{
+  std::lock_guard<std::mutex> lock(mu_);
+  nlohmann::json out = nlohmann::json::array();
+  for (int coil = kMinCoilId; coil <= kMaxCoilId; ++coil)
+  {
+    const bool value = coils_.count(coil) ? coils_.at(coil) : false;
+    if (value || store_.findTriggerByCoil(coil))
+    {
+      out.push_back({{"coil_id", coil}, {"value", value}});
+    }
+  }
+  return out;
+}
+
+void ModbusTriggerService::onCoilRisingEdgeUnlocked(int coil_id)
+{
+  (void)coil_id;
+}
+
+bool ModbusTriggerService::writeCoil(int coil_id, bool value, std::string& err)
+{
+  if (!coilIdValid(coil_id))
+  {
+    err = "coil_id must be between 1001 and 2000";
+    return false;
+  }
+  std::optional<std::string> mission_id;
+  {
+    std::lock_guard<std::mutex> lock(mu_);
+    const bool prev = coils_.count(coil_id) ? coils_.at(coil_id) : false;
+    coils_[coil_id] = value;
+    prev_coils_[coil_id] = value;
+    if (!prev && value)
+    {
+      const auto trigger = store_.findTriggerByCoil(coil_id);
+      if (trigger)
+        mission_id = trigger->value("mission_id", "");
+    }
+  }
+  if (mission_id)
+  {
+    nlohmann::json req = {{"mission_id", *mission_id}, {"source", "modbus:" + std::to_string(coil_id)}};
+    return enqueue_fn_(req, err);
+  }
+  return true;
+}
+
+bool ModbusTriggerService::fireCoil(int coil_id, std::string& err)
+{
+  return writeCoil(coil_id, true, err);
+}
+
+void ModbusTriggerService::handleTcpClient(int client_fd)
+{
+  std::vector<uint8_t> buffer(260);
+  const ssize_t n = recv(client_fd, buffer.data(), buffer.size(), 0);
+  if (n < 12)
+    return;
+
+  const uint8_t function = buffer[7];
+  if (function == 0x05 && n >= 12)
+  {
+    const uint16_t address = (static_cast<uint16_t>(buffer[8]) << 8) | buffer[9];
+    const uint16_t value = (static_cast<uint16_t>(buffer[10]) << 8) | buffer[11];
+    const int coil_id = modbusAddressToCoilId(address);
+    std::string err;
+    writeCoil(coil_id, value == 0xFF00, err);
+    send(client_fd, buffer.data(), static_cast<size_t>(n), 0);
+  }
+}
+
+void ModbusTriggerService::tcpLoop()
+{
+  const int server_fd = socket(AF_INET, SOCK_STREAM, 0);
+  if (server_fd < 0)
+    return;
+
+  int opt = 1;
+  setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
+
+  sockaddr_in addr{};
+  addr.sin_family = AF_INET;
+  addr.sin_addr.s_addr = INADDR_ANY;
+  addr.sin_port = htons(static_cast<uint16_t>(tcp_port_));
+  if (bind(server_fd, reinterpret_cast<sockaddr*>(&addr), sizeof(addr)) < 0)
+  {
+    close(server_fd);
+    return;
+  }
+  if (listen(server_fd, 8) < 0)
+  {
+    close(server_fd);
+    return;
+  }
+
+  while (!stop_)
+  {
+    fd_set fds;
+    FD_ZERO(&fds);
+    FD_SET(server_fd, &fds);
+    timeval tv{0, 200000};
+    if (select(server_fd + 1, &fds, nullptr, nullptr, &tv) <= 0)
+      continue;
+    const int client = accept(server_fd, nullptr, nullptr);
+    if (client < 0)
+      continue;
+    handleTcpClient(client);
+    close(client);
+  }
+  close(server_fd);
+}
+
+}  // namespace lm