Keep vanetza-idf in obu-firmware, so a plain clone builds the firmware

obu-firmware builds against the vanetza-idf C-ITS library, which until now
came from the colleague's microbu-esp32c5 tree beside the repository and was
not tracked here, so a clone of this repository could not build the firmware
it ships. The library alone is now part of obu-firmware, as
obu-firmware/external/vanetza-idf: their external/vanetza-idf at commit
cf4b99f, unchanged (9775 files; see its PROVENANCE.md). CMake takes it from
there by default; -DVANETZA_IDF_DIR still points the build elsewhere.

The rest of the colleague's tree (their own VAM firmware, PKI tooling,
station-link Python tools, the V2X2MAP bridge) stays out of this repository
and gitignored; nothing is pushed to their repository. NOTES.md, docs/06,
TODO.md and the pcap verifier's usage line point at the new location.

obu-firmware/external/vanetza-idf/tools/socktap/application.cpp

@@ -0,0 +1,65 @@
+#include "application.hpp"
+#include <vanetza/btp/header.hpp>
+#include <vanetza/btp/header_conversion.hpp>
+#include <cassert>
+
+using namespace vanetza;
+
+Application::DataConfirm Application::request(const DataRequest& request, DownPacketPtr packet)
+{
+    DataConfirm confirm(DataConfirm::ResultCode::Rejected_Unspecified);
+    if (router_ && packet) {
+        btp::HeaderB btp_header;
+        btp_header.destination_port = this->port();
+        btp_header.destination_port_info = host_cast<uint16_t>(0);
+        packet->layer(OsiLayer::Transport) = btp_header;
+
+        switch (request.transport_type) {
+            case geonet::TransportType::SHB:
+                confirm = router_->request(request_shb(request), std::move(packet));
+                break;
+            case geonet::TransportType::GBC:
+                confirm = router_->request(request_gbc(request), std::move(packet));
+                break;
+            default:
+                // TODO remaining transport types are not implemented
+                break;
+        }
+    }
+
+    return confirm;
+}
+
+void initialize_request(const Application::DataRequest& generic, geonet::DataRequest& geonet)
+{
+    geonet.upper_protocol = geonet::UpperProtocol::BTP_B;
+    geonet.communication_profile = generic.communication_profile;
+    geonet.its_aid = generic.its_aid;
+    if (generic.maximum_lifetime) {
+        geonet.maximum_lifetime = generic.maximum_lifetime.get();
+    }
+    geonet.repetition = generic.repetition;
+    geonet.traffic_class = generic.traffic_class;
+}
+
+geonet::GbcDataRequest Application::request_gbc(const DataRequest& generic)
+{
+    assert(router_);
+    geonet::GbcDataRequest gbc(router_->get_mib());
+    initialize_request(generic, gbc);
+    gbc.destination = boost::get<geonet::Area>(generic.destination);
+    return gbc;
+}
+
+geonet::ShbDataRequest Application::request_shb(const DataRequest& generic)
+{
+    assert(router_);
+    geonet::ShbDataRequest shb(router_->get_mib());
+    initialize_request(generic, shb);
+    return shb;
+}
+
+Application::PromiscuousHook* Application::promiscuous_hook()
+{
+    return nullptr;
+}