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/vanetza/btp/port_dispatcher.cpp

@@ -0,0 +1,94 @@
+#include "port_dispatcher.hpp"
+#include "data_indication.hpp"
+#include <vanetza/geonet/data_indication.hpp>
+#include <algorithm>
+#include <cassert>
+
+namespace vanetza
+{
+namespace btp
+{
+
+boost::optional<DataIndication> parse_btp_header(const geonet::DataIndication& gn_ind, PacketVariant& packet)
+{
+    boost::optional<DataIndication> indication;
+
+    switch (gn_ind.upper_protocol) {
+        case geonet::UpperProtocol::BTP_A: {
+            HeaderA hdr = parse_btp_a(packet);
+            indication = DataIndication(gn_ind, hdr);
+            }
+            break;
+        case geonet::UpperProtocol::BTP_B: {
+            HeaderB hdr = parse_btp_b(packet);
+            indication = DataIndication(gn_ind, hdr);
+            }
+            break;
+        default:
+            // drop non-BTP packet
+            break;
+    }
+
+    return indication;
+}
+
+void PortDispatcher::add_promiscuous_hook(PromiscuousHook* hook)
+{
+    if (hook != nullptr) {
+        auto it = std::find(m_promiscuous_hooks.begin(), m_promiscuous_hooks.end(), hook);
+        if (it == m_promiscuous_hooks.end()) {
+            m_promiscuous_hooks.push_back(hook);
+        }
+    }
+}
+
+void PortDispatcher::remove_promiscuous_hook(PromiscuousHook* hook)
+{
+    m_promiscuous_hooks.remove(hook);
+}
+
+void PortDispatcher::set_interactive_handler(
+        port_type port,
+        IndicationInterface* handler)
+{
+    m_interactive_handlers[port] = handler;
+}
+
+void PortDispatcher::set_non_interactive_handler(
+        port_type port,
+        IndicationInterface* handler)
+{
+    m_non_interactive_handlers[port] = handler;
+}
+
+void PortDispatcher::indicate(
+        const geonet::DataIndication& gn_ind,
+        std::unique_ptr<UpPacket> packet)
+{
+    assert(packet);
+    boost::optional<DataIndication> btp_ind = parse_btp_header(gn_ind, *packet);
+    IndicationInterface* handler = nullptr;
+
+    if (btp_ind) {
+        if (btp_ind->source_port) {
+            handler = m_interactive_handlers[btp_ind->destination_port];
+        } else {
+            handler = m_non_interactive_handlers[btp_ind->destination_port];
+        }
+
+        for (PromiscuousHook* hook : m_promiscuous_hooks) {
+            hook->tap_packet(*btp_ind, *packet);
+        }
+
+        if (handler) {
+            handler->indicate(*btp_ind, std::move(packet));
+        } else {
+            hook_undispatched(gn_ind, &btp_ind.get());
+        }
+    } else {
+        hook_undispatched(gn_ind, nullptr);
+    }
+}
+
+} // namespace btp
+} // namespace vanetza