Emit the packet after calculating TCP checksum

This should be the same as the UDP checksum, otherwise calculating the TCP checksum results in all packets being discarded.
NetSys · Mar 19, 2021 · 97a8f86 · 97a8f86
1 parent ae52fc5
commit 97a8f86
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/core/modules/l4_checksum.cc b/core/modules/l4_checksum.cc
@@ -76,8 +76,10 @@ void L4Checksum::ProcessBatch(Context *ctx, bess::PacketBatch *batch) {
       if (verify_)
 	EmitPacket(ctx, batch->pkts()[i],
 		   (VerifyIpv4TcpChecksum(*ip, *tcp)) ? FORWARD_GATE : FAIL_GATE);
-      else
-	tcp->checksum = CalculateIpv4TcpChecksum(*ip, *tcp);
+      else {
+        tcp->checksum = CalculateIpv4TcpChecksum(*ip, *tcp);
+        EmitPacket(ctx, batch->pkts()[i], FORWARD_GATE);
+      }
     }
   }
 }