Display packet loss

tunsafe_win32.cpp

@@ -1503,6 +1503,7 @@ static const AdvancedTextInfo ADVANCED_TEXT_INFOS[] = {
   {Y + 19 * 3, 66, "Handshake:"},
   {Y + 19 * 4, 66, ""},
   {Y + 19 * 5, 66, "Overhead:"},
+  {Y + 19 * 6, 66, "Packet Loss:"},
 #undef Y
 };
 
@@ -1579,6 +1580,12 @@ static const char *GetAdvancedInfoValue(char buffer[256], int i) {
              overhead_out_pct / 1000, overhead_out_pct % 1000);
     return buffer;
   }
+  case 6: {
+    snprintf(buffer, 256, "%.3f%% (%d packets)", 
+             ps->lost_packets_tot ? 100.0f * (ps->lost_packets_tot - ps->lost_packets_valid) / ps->lost_packets_tot : 0.0f,
+             (int)(ps->lost_packets_tot - ps->lost_packets_valid));
+    return buffer;
+  }
   default: return "";
   }  
 }

wireguard.cpp

@@ -95,6 +95,11 @@ const WgProcessorStats &WireguardProcessor::GetStats() {
   if (peer) {
     stats_.endpoint = peer->endpoint_;
     stats_.endpoint_protocol = peer->endpoint_protocol_;
+
+    if (peer->curr_keypair_) {
+      stats_.lost_packets_tot = peer->curr_keypair_->replay_detector.expected_seq_nr();
+      stats_.lost_packets_valid = peer->curr_keypair_->incoming_packet_count;
+    }
   }
   return stats_;
 }
@@ -434,8 +439,8 @@ add_padding:
     byte *write = data;
     uint8 tag = WG_SHORT_HEADER_BIT, inner_tag;
     // For every 16 incoming packets, send out an ack.
-    if (keypair->incoming_packet_count >= 16) {
-      keypair->incoming_packet_count = 0;
+    if ((uint32)(keypair->incoming_packet_count - keypair->send_ack_ctr) >= 16) {
+      keypair->send_ack_ctr = (uint32)keypair->incoming_packet_count;
       uint64 next_expected_packet = keypair->replay_detector.expected_seq_nr();
       if (next_expected_packet < 0x10000) {
         WriteLE16(write -= 2, (uint16)next_expected_packet);
@@ -794,7 +799,6 @@ void WireguardProcessor::HandleShortHeaderFormatPacket(uint32 tag, Packet *packe
   stats_.compression_wg_saved_in += 16 - (data - packet->data);
 
   keypair->send_ctr_acked = std::max<uint64>(keypair->send_ctr_acked, acked_counter);
-  keypair->incoming_packet_count++;
 
   WgPeer::CopyEndpointToPeer_Locked(keypair, &packet->addr);
 
@@ -836,6 +840,9 @@ void WireguardProcessor::HandleAuthenticatedDataPacket_WillUnlock(WgKeypair *key
   WgPeer *peer = keypair->peer;
   assert(peer->IsPeerLocked());
 
+  // Remember how many incoming packets we've seen so we can approximate loss
+  keypair->incoming_packet_count++;
+
   // Promote the next key to the current key when we receive a data packet,
   // the handshake is now complete.
   if (peer->CheckSwitchToNextKey_Locked(keypair)) {

wireguard.h

@@ -44,6 +44,12 @@ struct WgProcessorStats {
   // Address of the endpoint
   IpAddr endpoint;
 
+
+  // For lost packets calculation, the total # of incoming packets
+  uint64 lost_packets_valid;
+  // For lost packets calculation, the total # of incoming packets according to seqnr
+  uint64 lost_packets_tot;
+
   uint8 endpoint_protocol;
 };
 

wireguard_proto.h

@@ -704,18 +704,19 @@ struct WgKeypair {
 
   // Cipher suite
   uint8 cipher_suite;
-  
-  // Used so we know when to send out ack packets.
-  uint32 incoming_packet_count;
 
   // Id of the key in my map. (MainThread)
   uint32 local_key_id;
   // Id of the key in their map
   uint32 remote_key_id;
+  // Used to send out acks.
+  uint32 send_ack_ctr;
   // The timestamp of when the key was created, to be able to expire it
   uint64 key_timestamp;
   // The highest acked send_ctr value
   uint64 send_ctr_acked;
+  // Used to detect incoming packet loss
+  uint64 incoming_packet_count;
   // Counter value for chacha20 for outgoing packets
   uint64 send_ctr;
   // The key used for chacha20 encryption