socktap: refactor packet assembly for TCP link

VeNIT-Lab · Feb 8, 2025 · 0b241f3 · 0b241f3
1 parent e7b7a1c
commit 0b241f3
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Showing 2 changed files with 19 additions and 23 deletions.
diff --git a/tools/socktap/tcp_link.cpp b/tools/socktap/tcp_link.cpp
@@ -27,33 +27,30 @@ void TcpLink::indicate(IndicationCallback cb)
 void TcpLink::request(const access::DataRequest& request, std::unique_ptr<ChunkPacket> packet)
 {
     // create ethernet header
-    vanetza::ByteBuffer buffer = create_ethernet_header(request.destination_addr, request.source_addr, request.ether_type);
+    vanetza::ByteBuffer eth = create_ethernet_header(request.destination_addr, request.source_addr, request.ether_type);
+    packet->layer(OsiLayer::Link) = std::move(eth);
 
-    // insert packet size before ethernet header
-    uint16_t packet_size = packet->size(OsiLayer::Network, OsiLayer::Application) + EthernetHeader::length_bytes;
-    buffer.insert(buffer.begin(), packet_size & 0x00FF);
-    buffer.insert(buffer.begin(), (packet_size & 0xFF00) >> 8);
-
-    packet->layer(OsiLayer::Link) = std::move(buffer);
+    // insert packet size as frame delimiter
+    uint16_t packet_size = packet->size(OsiLayer::Link, OsiLayer::Application);
+    vanetza::ByteBuffer frame_delimiter { uint8_t(packet_size >> 8), uint8_t(packet_size) };
+    packet->layer(OsiLayer::Physical) = std::move(frame_delimiter);
 
     std::array<boost::asio::const_buffer, layers_> const_buffers;
-    for (auto& layer : osi_layer_range<OsiLayer::Link, OsiLayer::Application>()) {
-        const auto index = distance(OsiLayer::Link, layer);
+    for (auto& layer : osi_layer_range<OsiLayer::Physical, OsiLayer::Application>()) {
+        const auto index = distance(OsiLayer::Physical, layer);
         packet->layer(layer).convert(tx_buffers_[index]);
         const_buffers[index] = boost::asio::buffer(tx_buffers_[index]);
     }
 
-    std::list<TcpSocket>::iterator i = sockets_.begin();
-
-    while (i != sockets_.end()) {
-        if ((*i).status() == TcpSocket::CONNECTED) {
-            (*i).request(const_buffers);
-            i++;
-        } else if ((*i).status() == TcpSocket::ERROR) {
-            sockets_.erase(i++);
+    for (auto it = sockets_.begin(); it != sockets_.end();) {
+        if (it->status() == TcpSocket::CONNECTED) {
+            it->request(const_buffers);
+            ++it;
+        } else if (it->status() == TcpSocket::ERROR) {
+            it = sockets_.erase(it);
             std::cerr << "Socket removed" << std::endl;
         } else {
-            i++;
+            ++it;
         }
     }
 }
@@ -149,16 +146,15 @@ void TcpSocket::do_receive()
 void TcpSocket::receive_handler(boost::system::error_code ec, std::size_t length) {
     if (!ec) {
         status_ = CONNECTED;
-
         rx_store_.insert(rx_store_.end(), rx_buffer_.begin(), rx_buffer_.begin() + length);
 
         // While we have enough bytes stored to construct a packet, pass it up
         while (rx_store_.size() >= get_next_packet_size() + 2)
         {
-            uint16_t packet_length = get_next_packet_size();
-            ByteBuffer packet_buffer(rx_store_.begin() + 2, rx_store_.begin() + 2 + packet_length);
+            uint16_t packet_length = get_next_packet_size() + 2;
+            ByteBuffer packet_buffer(rx_store_.begin() + 2, rx_store_.begin() + packet_length);
             pass_up(std::move(packet_buffer));
-            rx_store_.erase(rx_store_.begin(), rx_store_.begin() + 2 + packet_length);
+            rx_store_.erase(rx_store_.begin(), rx_store_.begin() + packet_length);
         }
 
         do_receive();

diff --git a/tools/socktap/tcp_link.hpp b/tools/socktap/tcp_link.hpp
@@ -8,7 +8,7 @@
 #include <array>
 #include <list>
 
-static constexpr std::size_t layers_ = num_osi_layers(vanetza::OsiLayer::Link, vanetza::OsiLayer::Application);
+static constexpr std::size_t layers_ = num_osi_layers(vanetza::OsiLayer::Physical, vanetza::OsiLayer::Application);
 
 
 class TcpSocket