NAT44: interface output feature and service host direct access (VPP-1176)

forwarding mode:
session initiaded from service host - translate
session initiaded from remote host - do not translate

Change-Id: I48170ee8e4ad14d3d3083ee31a40ef8d10d6ff32
Signed-off-by: Matus Fabian <matfabia@cisco.com>

2 files changed, 117 insertions, 6 deletions

diff --git a/src/plugins/nat/in2out.c b/src/plugins/nat/in2out.c
index 003b1ad3858..24895a0fb11 100755
--- a/src/plugins/nat/in2out.c
+++ b/src/plugins/nat/in2out.c
@@ -470,6 +470,47 @@ icmp_get_ed_key(ip4_header_t *ip0, nat_ed_ses_key_t *p_key0)
   return 0;
 }
 
+static inline int
+nat_not_translate_output_feature_fwd (snat_main_t * sm, ip4_header_t * ip)
+{
+  nat_ed_ses_key_t key;
+  clib_bihash_kv_16_8_t kv, value;
+  udp_header_t *udp;
+
+  if (!sm->forwarding_enabled)
+    return 0;
+
+  if (ip->protocol == IP_PROTOCOL_ICMP)
+    {
+      if (icmp_get_ed_key (ip, &key))
+        return 0;
+    }
+  else if (ip->protocol == IP_PROTOCOL_UDP || ip->protocol == IP_PROTOCOL_TCP)
+    {
+      udp = ip4_next_header(ip);
+      key.l_addr = ip->src_address;
+      key.r_addr = ip->dst_address;
+      key.proto = ip->protocol;
+      key.r_port = udp->dst_port;
+      key.l_port = udp->src_port;
+    }
+  else
+    {
+      key.l_addr = ip->src_address;
+      key.r_addr = ip->dst_address;
+      key.proto = ip->protocol;
+      key.l_port = key.r_port = 0;
+    }
+  key.fib_index = 0;
+  kv.key[0] = key.as_u64[0];
+  kv.key[1] = key.as_u64[1];
+
+  if (!clib_bihash_search_16_8 (&sm->in2out_ed, &kv, &value))
+    return value.value == ~0ULL;
+
+  return 0;
+}
+
 /**
  * Get address and port values to be used for ICMP packet translation
  * and create session if needed
@@ -1290,6 +1331,8 @@ snat_in2out_lb (snat_main_t *sm,
 
   if (!clib_bihash_search_16_8 (&sm->in2out_ed, &s_kv, &s_value))
     {
+      if (s_value.value == ~0ULL)
+        return 0;
       s = pool_elt_at_index (tsm->sessions, s_value.value);
     }
   else
@@ -1524,6 +1567,12 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
             }
           else
             {
+              if (is_output_feature)
+                {
+                  if (PREDICT_FALSE(nat_not_translate_output_feature_fwd(sm, ip0)))
+                    goto trace00;
+                }
+
               if (PREDICT_FALSE (proto0 == ~0 || proto0 == SNAT_PROTOCOL_ICMP))
                 {
                   next0 = SNAT_IN2OUT_NEXT_SLOW_PATH;
@@ -1710,6 +1759,12 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
             }
           else
             {
+              if (is_output_feature)
+                {
+                  if (PREDICT_FALSE(nat_not_translate_output_feature_fwd(sm, ip1)))
+                    goto trace01;
+                }
+
               if (PREDICT_FALSE (proto1 == ~0 || proto1 == SNAT_PROTOCOL_ICMP))
                 {
                   next1 = SNAT_IN2OUT_NEXT_SLOW_PATH;
@@ -1723,8 +1778,6 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
                 }
             }
 
-          b1->flags |= VNET_BUFFER_F_IS_NATED;
-
           key1.addr = ip1->src_address;
           key1.port = udp1->src_port;
           key1.protocol = proto1;
@@ -1787,6 +1840,8 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
                 }
             }
 
+          b1->flags |= VNET_BUFFER_F_IS_NATED;
+
           old_addr1 = ip1->src_address.as_u32;
           ip1->src_address = s1->out2in.addr;
           new_addr1 = ip1->src_address.as_u32;
@@ -1932,6 +1987,12 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
             }
           else
             {
+               if (is_output_feature)
+                {
+                  if (PREDICT_FALSE(nat_not_translate_output_feature_fwd(sm, ip0)))
+                    goto trace0;
+                }
+
               if (PREDICT_FALSE (proto0 == ~0 || proto0 == SNAT_PROTOCOL_ICMP))
                 {
                   next0 = SNAT_IN2OUT_NEXT_SLOW_PATH;
diff --git a/src/plugins/nat/out2in.c b/src/plugins/nat/out2in.c
index a03f780ba5e..4589c48aef6 100755
--- a/src/plugins/nat/out2in.c
+++ b/src/plugins/nat/out2in.c
@@ -311,6 +311,43 @@ icmp_get_ed_key(ip4_header_t *ip0, nat_ed_ses_key_t *p_key0)
   return 0;
 }
 
+static void
+create_bypass_for_fwd(snat_main_t * sm, ip4_header_t * ip)
+{
+  nat_ed_ses_key_t key;
+  clib_bihash_kv_16_8_t kv;
+  udp_header_t *udp;
+
+  if (ip->protocol == IP_PROTOCOL_ICMP)
+    {
+      if (icmp_get_ed_key (ip, &key))
+        return;
+    }
+  else if (ip->protocol == IP_PROTOCOL_UDP || ip->protocol == IP_PROTOCOL_TCP)
+    {
+      udp = ip4_next_header(ip);
+      key.r_addr = ip->src_address;
+      key.l_addr = ip->dst_address;
+      key.proto = ip->protocol;
+      key.l_port = udp->dst_port;
+      key.r_port = udp->src_port;
+    }
+  else
+    {
+      key.r_addr = ip->src_address;
+      key.l_addr = ip->dst_address;
+      key.proto = ip->protocol;
+      key.l_port = key.r_port = 0;
+    }
+  key.fib_index = 0;
+  kv.key[0] = key.as_u64[0];
+  kv.key[1] = key.as_u64[1];
+  kv.value = ~0ULL;
+
+  if (clib_bihash_add_del_16_8 (&sm->in2out_ed, &kv, 1))
+    clib_warning ("in2out_ed key add failed");
+}
+
 /**
  * Get address and port values to be used for ICMP packet translation
  * and create session if needed
@@ -382,6 +419,7 @@ u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
             }
           else
             {
+              create_bypass_for_fwd(sm, ip0);
               dont_translate = 1;
               goto out;
             }
@@ -1116,7 +1154,10 @@ snat_out2in_node_fn (vlib_main_t * vm,
                       goto trace0;
                     }
                   else
-                    goto trace0;
+                    {
+                      create_bypass_for_fwd(sm, ip0);
+                      goto trace0;
+                    }
                 }
 
               /* Create session initiated by host from external network */
@@ -1283,7 +1324,10 @@ snat_out2in_node_fn (vlib_main_t * vm,
                       goto trace1;
                     }
                   else
-                    goto trace1;
+                    {
+                      create_bypass_for_fwd(sm, ip1);
+                      goto trace1;
+                    }
                 }
 
               /* Create session initiated by host from external network */
@@ -1486,7 +1530,10 @@ snat_out2in_node_fn (vlib_main_t * vm,
                       goto trace00;
                     }
                   else
-                    goto trace00;
+                    {
+                      create_bypass_for_fwd(sm, ip0);
+                      goto trace00;
+                    }
                 }
 
               /* Create session initiated by host from external network */
@@ -1730,7 +1777,10 @@ nat44_out2in_reass_node_fn (vlib_main_t * vm,
                           goto trace0;
                         }
                       else
-                        goto trace0;
+                        {
+                          create_bypass_for_fwd(sm, ip0);
+                          goto trace0;
+                        }
                     }
 
                   /* Create session initiated by host from external network */