udp: fix inner packet checksum calculation in udp-encap

When computing the inner packet checksum, the code wrongly
assumes that the IP version of the inner packet is the
same of the outer one. On the contrary, it is perfectly
possible to encapsulate v6 packets into v4 and viceversa,
so we need to check the IP format of the inner header before
calling vnet_calc_checksums_inline.

Ticket: VPP-2020
Type: fix

Signed-off-by: Mauro Sardara <msardara@cisco.com>
Change-Id: Ia4515563c164f6dd5096832c831a48cb0a29b3ad
Signed-off-by: Mauro Sardara <msardara@cisco.com>

4 files changed, 103 insertions, 41 deletions

diff --git a/src/vnet/udp/udp_encap.c b/src/vnet/udp/udp_encap.c
index cb93adb8d39..a0f5a50c223 100644
--- a/src/vnet/udp/udp_encap.c
+++ b/src/vnet/udp/udp_encap.c
@@ -47,8 +47,7 @@ static void
 udp_encap_restack (udp_encap_t * ue)
 {
   dpo_stack (udp_encap_dpo_types[ue->ue_ip_proto],
-	     fib_proto_to_dpo (ue->ue_ip_proto),
-	     &ue->ue_dpo,
+	     fib_proto_to_dpo (ue->ue_ip_proto), &ue->ue_dpo,
 	     fib_entry_contribute_ip_forwarding (ue->ue_fib_entry_index));
 }
 
@@ -325,12 +324,12 @@ udp_encap_fib_last_lock_gone (fib_node_t * node)
 }
 
 const static char *const udp4_encap_ip4_nodes[] = {
-  "udp4-encap",
+  "udp4o4-encap",
   NULL,
 };
 
 const static char *const udp4_encap_ip6_nodes[] = {
-  "udp4-encap",
+  "udp6o4-encap",
   NULL,
 };
 
@@ -345,12 +344,12 @@ const static char *const udp4_encap_bier_nodes[] = {
 };
 
 const static char *const udp6_encap_ip4_nodes[] = {
-  "udp6-encap",
+  "udp4o6-encap",
   NULL,
 };
 
 const static char *const udp6_encap_ip6_nodes[] = {
-  "udp6-encap",
+  "udp6o6-encap",
   NULL,
 };
 
diff --git a/src/vnet/udp/udp_encap.h b/src/vnet/udp/udp_encap.h
index b096e0f5c09..648e3b59e6d 100644
--- a/src/vnet/udp/udp_encap.h
+++ b/src/vnet/udp/udp_encap.h
@@ -85,7 +85,7 @@ typedef struct udp_encap_t_
   /**
    * The second cacheline contains control-plane data
    */
-    CLIB_CACHE_LINE_ALIGN_MARK (cacheline1);
+  CLIB_CACHE_LINE_ALIGN_MARK (cacheline1);
 
   /**
    * linkage into the FIB graph
diff --git a/src/vnet/udp/udp_encap_node.c b/src/vnet/udp/udp_encap_node.c
index 5b9fc0bf34b..1ebe79532f4 100644
--- a/src/vnet/udp/udp_encap_node.c
+++ b/src/vnet/udp/udp_encap_node.c
@@ -61,9 +61,9 @@ format_udp6_encap_trace (u8 * s, va_list * args)
 }
 
 always_inline uword
-udp_encap_inline (vlib_main_t * vm,
-		  vlib_node_runtime_t * node,
-		  vlib_frame_t * frame, int is_encap_v6)
+udp_encap_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
+		  vlib_frame_t *frame, ip_address_family_t encap_family,
+		  ip_address_family_t payload_family)
 {
   vlib_combined_counter_main_t *cm = &udp_encap_counters;
   u32 *from = vlib_frame_vector_args (frame);
@@ -121,12 +121,13 @@ udp_encap_inline (vlib_main_t * vm,
 	  ue1 = udp_encap_get (uei1);
 
 	  /* Paint */
-	  if (is_encap_v6)
+	  if (encap_family == AF_IP6)
 	    {
 	      const u8 n_bytes =
 		sizeof (udp_header_t) + sizeof (ip6_header_t);
-	      ip_udp_encap_two (vm, b0, b1, (u8 *) & ue0->ue_hdrs,
-				(u8 *) & ue1->ue_hdrs, n_bytes, 0);
+	      ip_udp_encap_two (vm, b0, b1, (u8 *) &ue0->ue_hdrs,
+				(u8 *) &ue1->ue_hdrs, n_bytes, encap_family,
+				payload_family);
 	      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
 		{
 		  udp6_encap_trace_t *tr =
@@ -147,9 +148,9 @@ udp_encap_inline (vlib_main_t * vm,
 	      const u8 n_bytes =
 		sizeof (udp_header_t) + sizeof (ip4_header_t);
 
-	      ip_udp_encap_two (vm, b0, b1,
-				(u8 *) & ue0->ue_hdrs,
-				(u8 *) & ue1->ue_hdrs, n_bytes, 1);
+	      ip_udp_encap_two (vm, b0, b1, (u8 *) &ue0->ue_hdrs,
+				(u8 *) &ue1->ue_hdrs, n_bytes, encap_family,
+				payload_family);
 
 	      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
 		{
@@ -202,12 +203,12 @@ udp_encap_inline (vlib_main_t * vm,
 									b0));
 
 	  /* Paint */
-	  if (is_encap_v6)
+	  if (encap_family == AF_IP6)
 	    {
 	      const u8 n_bytes =
 		sizeof (udp_header_t) + sizeof (ip6_header_t);
-	      ip_udp_encap_one (vm, b0, (u8 *) & ue0->ue_hdrs.ip6, n_bytes,
-				0);
+	      ip_udp_encap_one (vm, b0, (u8 *) &ue0->ue_hdrs.ip6, n_bytes,
+				encap_family, payload_family);
 
 	      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
 		{
@@ -222,8 +223,8 @@ udp_encap_inline (vlib_main_t * vm,
 	      const u8 n_bytes =
 		sizeof (udp_header_t) + sizeof (ip4_header_t);
 
-	      ip_udp_encap_one (vm, b0, (u8 *) & ue0->ue_hdrs.ip4, n_bytes,
-				1);
+	      ip_udp_encap_one (vm, b0, (u8 *) &ue0->ue_hdrs.ip4, n_bytes,
+				encap_family, payload_family);
 
 	      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
 		{
@@ -248,37 +249,87 @@ udp_encap_inline (vlib_main_t * vm,
   return frame->n_vectors;
 }
 
-VLIB_NODE_FN (udp4_encap_node) (vlib_main_t * vm,
-				vlib_node_runtime_t * node,
-				vlib_frame_t * frame)
+VLIB_NODE_FN (udp4o4_encap_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
-  return udp_encap_inline (vm, node, frame, 0);
+  return udp_encap_inline (vm, node, frame, AF_IP4, AF_IP4);
 }
 
-VLIB_NODE_FN (udp6_encap_node) (vlib_main_t * vm,
-				vlib_node_runtime_t * node,
-				vlib_frame_t * frame)
+VLIB_NODE_FN (udp6o4_encap_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
-  return udp_encap_inline (vm, node, frame, 1);
+  return udp_encap_inline (vm, node, frame, AF_IP4, AF_IP6);
+}
+
+VLIB_NODE_FN (udp4_encap_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+  return udp_encap_inline (vm, node, frame, AF_IP4, N_AF);
+}
+
+VLIB_NODE_FN (udp6o6_encap_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+  return udp_encap_inline (vm, node, frame, AF_IP6, AF_IP6);
+}
+
+VLIB_NODE_FN (udp4o6_encap_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+  return udp_encap_inline (vm, node, frame, AF_IP6, AF_IP4);
+}
+
+VLIB_NODE_FN (udp6_encap_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+  return udp_encap_inline (vm, node, frame, AF_IP6, N_AF);
 }
 
 /* *INDENT-OFF* */
+VLIB_REGISTER_NODE (udp4o4_encap_node) = {
+  .name = "udp4o4-encap",
+  .vector_size = sizeof (u32),
+  .format_trace = format_udp4_encap_trace,
+  .n_next_nodes = 0,
+};
+
+VLIB_REGISTER_NODE (udp6o4_encap_node) = {
+  .name = "udp6o4-encap",
+  .vector_size = sizeof (u32),
+  .format_trace = format_udp6_encap_trace,
+  .n_next_nodes = 0,
+  .sibling_of = "udp4o4-encap",
+};
+
 VLIB_REGISTER_NODE (udp4_encap_node) = {
   .name = "udp4-encap",
   .vector_size = sizeof (u32),
-
   .format_trace = format_udp4_encap_trace,
+  .n_next_nodes = 0,
+  .sibling_of = "udp4o4-encap",
+};
 
+VLIB_REGISTER_NODE (udp6o6_encap_node) = {
+  .name = "udp6o6-encap",
+  .vector_size = sizeof (u32),
+  .format_trace = format_udp6_encap_trace,
+  .n_next_nodes = 0,
+};
+
+VLIB_REGISTER_NODE (udp4o6_encap_node) = {
+  .name = "udp4o6-encap",
+  .vector_size = sizeof (u32),
+  .format_trace = format_udp4_encap_trace,
   .n_next_nodes = 0,
+  .sibling_of = "udp6o6-encap",
 };
 
 VLIB_REGISTER_NODE (udp6_encap_node) = {
   .name = "udp6-encap",
   .vector_size = sizeof (u32),
-
   .format_trace = format_udp6_encap_trace,
-
   .n_next_nodes = 0,
+  .sibling_of = "udp6o6-encap",
 };
 /* *INDENT-ON* */
 
diff --git a/src/vnet/udp/udp_inlines.h b/src/vnet/udp/udp_inlines.h
index e4eb0c88e83..d79dc9a2bad 100644
--- a/src/vnet/udp/udp_inlines.h
+++ b/src/vnet/udp/udp_inlines.h
@@ -97,14 +97,20 @@ ip_udp_fixup_one (vlib_main_t * vm, vlib_buffer_t * b0, u8 is_ip4)
 }
 
 always_inline void
-ip_udp_encap_one (vlib_main_t * vm, vlib_buffer_t * b0, u8 * ec0, word ec_len,
-		  u8 is_ip4)
+ip_udp_encap_one (vlib_main_t *vm, vlib_buffer_t *b0, u8 *ec0, word ec_len,
+		  ip_address_family_t encap_family,
+		  ip_address_family_t payload_family)
 {
-  vnet_calc_checksums_inline (vm, b0, is_ip4, !is_ip4);
+
+  if (payload_family < N_AF)
+    {
+      vnet_calc_checksums_inline (vm, b0, payload_family == AF_IP4,
+				  payload_family == AF_IP6);
+    }
 
   vlib_buffer_advance (b0, -ec_len);
 
-  if (is_ip4)
+  if (encap_family == AF_IP4)
     {
       ip4_header_t *ip0;
 
@@ -127,21 +133,27 @@ ip_udp_encap_one (vlib_main_t * vm, vlib_buffer_t * b0, u8 * ec0, word ec_len,
 }
 
 always_inline void
-ip_udp_encap_two (vlib_main_t * vm, vlib_buffer_t * b0, vlib_buffer_t * b1,
-		  u8 * ec0, u8 * ec1, word ec_len, u8 is_v4)
+ip_udp_encap_two (vlib_main_t *vm, vlib_buffer_t *b0, vlib_buffer_t *b1,
+		  u8 *ec0, u8 *ec1, word ec_len,
+		  ip_address_family_t encap_family,
+		  ip_address_family_t payload_family)
 {
   u16 new_l0, new_l1;
   udp_header_t *udp0, *udp1;
+  int payload_ip4 = (payload_family == AF_IP4);
 
   ASSERT (_vec_len (ec0) == _vec_len (ec1));
 
-  vnet_calc_checksums_inline (vm, b0, is_v4, !is_v4);
-  vnet_calc_checksums_inline (vm, b1, is_v4, !is_v4);
+  if (payload_family < N_AF)
+    {
+      vnet_calc_checksums_inline (vm, b0, payload_ip4, !payload_ip4);
+      vnet_calc_checksums_inline (vm, b1, payload_ip4, !payload_ip4);
+    }
 
   vlib_buffer_advance (b0, -ec_len);
   vlib_buffer_advance (b1, -ec_len);
 
-  if (is_v4)
+  if (encap_family == AF_IP4)
     {
       ip4_header_t *ip0, *ip1;
       ip_csum_t sum0, sum1;