nat: respect udp checksum

Type: fix

Change-Id: I73895fa0101bd50483160c8dc6faac2c67513077
Signed-off-by: Filip Varga <fivarga@cisco.com>

1 files changed, 74 insertions, 34 deletions

diff --git a/src/plugins/nat/out2in.c b/src/plugins/nat/out2in.c
index 8c6cb482703..83c099d1bd2 100755
--- a/src/plugins/nat/out2in.c
+++ b/src/plugins/nat/out2in.c
@@ -893,6 +893,9 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 				 dst_address /* changed member */ );
 	  ip0->checksum = ip_csum_fold (sum0);
 
+	  old_port0 = udp0->dst_port;
+	  new_port0 = udp0->dst_port = s0->in2out.port;
+
 	  if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 	    {
 	      old_port0 = tcp0->dst_port;
@@ -912,9 +915,17 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 	    }
 	  else
 	    {
-	      old_port0 = udp0->dst_port;
-	      udp0->dst_port = s0->in2out.port;
-	      udp0->checksum = 0;
+	      if (PREDICT_FALSE (udp0->checksum))
+		{
+		  sum0 = udp0->checksum;
+		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+					 ip4_header_t,
+					 dst_address /* changed member */ );
+		  sum0 = ip_csum_update (sum0, old_port0, new_port0,
+					 ip4_header_t /* cheat */ ,
+					 length /* changed member */ );
+		  udp0->checksum = ip_csum_fold (sum0);
+		}
 	      udp_packets++;
 	    }
 
@@ -1059,12 +1070,11 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 				 dst_address /* changed member */ );
 	  ip1->checksum = ip_csum_fold (sum1);
 
+	  old_port1 = udp1->dst_port;
+	  new_port1 = udp1->dst_port = s1->in2out.port;
+
 	  if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
 	    {
-	      old_port1 = tcp1->dst_port;
-	      tcp1->dst_port = s1->in2out.port;
-	      new_port1 = tcp1->dst_port;
-
 	      sum1 = tcp1->checksum;
 	      sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
 				     ip4_header_t,
@@ -1078,9 +1088,17 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 	    }
 	  else
 	    {
-	      old_port1 = udp1->dst_port;
-	      udp1->dst_port = s1->in2out.port;
-	      udp1->checksum = 0;
+	      if (PREDICT_FALSE (udp1->checksum))
+		{
+		  sum1 = udp1->checksum;
+		  sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
+					 ip4_header_t,
+					 dst_address /* changed member */ );
+		  sum1 = ip_csum_update (sum1, old_port1, new_port1,
+					 ip4_header_t /* cheat */ ,
+					 length /* changed member */ );
+		  udp1->checksum = ip_csum_fold (sum1);
+		}
 	      udp_packets++;
 	    }
 
@@ -1262,12 +1280,11 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 				 dst_address /* changed member */ );
 	  ip0->checksum = ip_csum_fold (sum0);
 
+	  old_port0 = udp0->dst_port;
+	  new_port0 = udp0->dst_port = s0->in2out.port;
+
 	  if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 	    {
-	      old_port0 = tcp0->dst_port;
-	      tcp0->dst_port = s0->in2out.port;
-	      new_port0 = tcp0->dst_port;
-
 	      sum0 = tcp0->checksum;
 	      sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 				     ip4_header_t,
@@ -1281,9 +1298,17 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 	    }
 	  else
 	    {
-	      old_port0 = udp0->dst_port;
-	      udp0->dst_port = s0->in2out.port;
-	      udp0->checksum = 0;
+	      if (PREDICT_FALSE (udp0->checksum))
+		{
+		  sum0 = udp0->checksum;
+		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+					 ip4_header_t,
+					 dst_address /* changed member */ );
+		  sum0 = ip_csum_update (sum0, old_port0, new_port0,
+					 ip4_header_t /* cheat */ ,
+					 length /* changed member */ );
+		  udp0->checksum = ip_csum_fold (sum0);
+		}
 	      udp_packets++;
 	    }
 
@@ -1573,12 +1598,11 @@ VLIB_NODE_FN (nat44_out2in_reass_node) (vlib_main_t * vm,
 
 	  if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
 	    {
+	      old_port0 = udp0->dst_port;
+	      new_port0 = udp0->dst_port = s0->in2out.port;
+
 	      if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 		{
-		  old_port0 = tcp0->dst_port;
-		  tcp0->dst_port = s0->in2out.port;
-		  new_port0 = tcp0->dst_port;
-
 		  sum0 = tcp0->checksum;
 		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 					 ip4_header_t,
@@ -1589,11 +1613,16 @@ VLIB_NODE_FN (nat44_out2in_reass_node) (vlib_main_t * vm,
 					 length /* changed member */ );
 		  tcp0->checksum = ip_csum_fold (sum0);
 		}
-	      else
+	      else if (udp0->checksum)
 		{
-		  old_port0 = udp0->dst_port;
-		  udp0->dst_port = s0->in2out.port;
-		  udp0->checksum = 0;
+		  sum0 = udp0->checksum;
+		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+					 ip4_header_t,
+					 dst_address /* changed member */ );
+		  sum0 = ip_csum_update (sum0, old_port0, new_port0,
+					 ip4_header_t /* cheat */ ,
+					 length /* changed member */ );
+		  udp0->checksum = ip_csum_fold (sum0);
 		}
 	    }
 
@@ -1797,26 +1826,30 @@ VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
 
 	  if (PREDICT_FALSE (new_port0 != udp0->dst_port))
 	    {
+	      old_port0 = udp0->dst_port;
+	      udp0->dst_port = new_port0;
+
 	      if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 		{
-		  old_port0 = tcp0->dst_port;
-		  tcp0->dst_port = new_port0;
-
 		  sum0 = tcp0->checksum;
 		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 					 ip4_header_t,
 					 dst_address /* changed member */ );
-
 		  sum0 = ip_csum_update (sum0, old_port0, new_port0,
 					 ip4_header_t /* cheat */ ,
 					 length /* changed member */ );
 		  tcp0->checksum = ip_csum_fold (sum0);
 		}
-	      else
+	      else if (udp0->checksum)
 		{
-		  old_port0 = udp0->dst_port;
-		  udp0->dst_port = new_port0;
-		  udp0->checksum = 0;
+		  sum0 = udp0->checksum;
+		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+					 ip4_header_t,
+					 dst_address /* changed member */ );
+		  sum0 = ip_csum_update (sum0, old_port0, new_port0,
+					 ip4_header_t /* cheat */ ,
+					 length /* changed member */ );
+		  udp0->checksum = ip_csum_fold (sum0);
 		}
 	    }
 	  else
@@ -1827,9 +1860,16 @@ VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
 		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 					 ip4_header_t,
 					 dst_address /* changed member */ );
-
 		  tcp0->checksum = ip_csum_fold (sum0);
 		}
+	      else if (udp0->checksum)
+		{
+		  sum0 = udp0->checksum;
+		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+					 ip4_header_t,
+					 dst_address /* changed member */ );
+		  udp0->checksum = ip_csum_fold (sum0);
+		}
 	    }
 
 	trace00: