nat: refactor mss_clamping to not depend on snat_main_t

Type: refactor
Signed-off-by: Ole Troan <ot@cisco.com>
Change-Id: I1110e425859a4f1f07952c91b50f263cb7323836

9 files changed, 83 insertions, 68 deletions

diff --git a/src/plugins/nat/in2out.c b/src/plugins/nat/in2out.c
index a448867cd4f..980a638f059 100644
--- a/src/plugins/nat/in2out.c
+++ b/src/plugins/nat/in2out.c
@@ -35,6 +35,7 @@
 #include <vppinfra/hash.h>
 #include <vppinfra/error.h>
 #include <vppinfra/elog.h>
+#include <nat/lib/nat_inlines.h>
 
 typedef struct
 {
@@ -1109,7 +1110,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 		  sum0 = ip_csum_update (sum0, old_port0, new_port0,
 					 ip4_header_t /* cheat */ ,
 					 length /* changed member */ );
-		  mss_clamping (sm, tcp0, &sum0);
+		  mss_clamping (sm->mss_clamping, tcp0, &sum0);
 		  tcp0->checksum = ip_csum_fold (sum0);
 		}
 	      tcp_packets++;
@@ -1317,7 +1318,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 		  sum1 = ip_csum_update (sum1, old_port1, new_port1,
 					 ip4_header_t /* cheat */ ,
 					 length /* changed member */ );
-		  mss_clamping (sm, tcp1, &sum1);
+		  mss_clamping (sm->mss_clamping, tcp1, &sum1);
 		  tcp1->checksum = ip_csum_fold (sum1);
 		}
 	      tcp_packets++;
@@ -1560,7 +1561,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 		  sum0 = ip_csum_update (sum0, old_port0, new_port0,
 					 ip4_header_t /* cheat */ ,
 					 length /* changed member */ );
-		  mss_clamping (sm, tcp0, &sum0);
+		  mss_clamping (sm->mss_clamping, tcp0, &sum0);
 		  tcp0->checksum = ip_csum_fold (sum0);
 		}
 	      tcp_packets++;
@@ -1885,7 +1886,7 @@ VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
 		  sum0 = ip_csum_update (sum0, old_port0, new_port0,
 					 ip4_header_t /* cheat */ ,
 					 length /* changed member */ );
-		  mss_clamping (sm, tcp0, &sum0);
+		  mss_clamping (sm->mss_clamping, tcp0, &sum0);
 		  tcp0->checksum = ip_csum_fold (sum0);
 		}
 	      else if (udp0->checksum)
@@ -1908,7 +1909,7 @@ VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
 		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 					 ip4_header_t,
 					 dst_address /* changed member */ );
-		  mss_clamping (sm, tcp0, &sum0);
+		  mss_clamping (sm->mss_clamping, tcp0, &sum0);
 		  tcp0->checksum = ip_csum_fold (sum0);
 		}
 	      else if (udp0->checksum)
diff --git a/src/plugins/nat/in2out_ed.c b/src/plugins/nat/in2out_ed.c
index 06e6772840b..9b10d9df7f6 100644
--- a/src/plugins/nat/in2out_ed.c
+++ b/src/plugins/nat/in2out_ed.c
@@ -32,6 +32,7 @@
 #include <nat/nat_syslog.h>
 #include <nat/nat_ha.h>
 #include <nat/nat44/ed_inlines.h>
+#include <nat/lib/nat_inlines.h>
 
 static char *nat_in2out_ed_error_strings[] = {
 #define _(sym,string) string,
@@ -1096,7 +1097,7 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t * vm,
 		      tcp0->dst_port = s0->ext_host_port;
 		      ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
 		    }
-		  mss_clamping (sm, tcp0, &sum0);
+		  mss_clamping (sm->mss_clamping, tcp0, &sum0);
 		  tcp0->checksum = ip_csum_fold (sum0);
 		}
 	      tcp_packets++;
@@ -1406,7 +1407,7 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t * vm,
 		      tcp0->dst_port = s0->ext_host_port;
 		      ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
 		    }
-		  mss_clamping (sm, tcp0, &sum0);
+		  mss_clamping (sm->mss_clamping, tcp0, &sum0);
 		  tcp0->checksum = ip_csum_fold (sum0);
 		}
 	      tcp_packets++;
diff --git a/src/plugins/nat/lib/nat_inlines.h b/src/plugins/nat/lib/nat_inlines.h
new file mode 100644
index 00000000000..fc8e160bb2b
--- /dev/null
+++ b/src/plugins/nat/lib/nat_inlines.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2020 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vnet/tcp/tcp_packet.h>
+#include <vnet/ip/ip4_packet.h>
+
+always_inline void
+mss_clamping (u16 mss_clamping, tcp_header_t * tcp, ip_csum_t * sum)
+{
+  u8 *data;
+  u8 opt_len, opts_len, kind;
+  u16 mss;
+
+  if (!(mss_clamping && tcp_syn (tcp)))
+    return;
+
+  opts_len = (tcp_doff (tcp) << 2) - sizeof (tcp_header_t);
+  data = (u8 *) (tcp + 1);
+  for (; opts_len > 0; opts_len -= opt_len, data += opt_len)
+    {
+      kind = data[0];
+
+      if (kind == TCP_OPTION_EOL)
+	break;
+      else if (kind == TCP_OPTION_NOOP)
+	{
+	  opt_len = 1;
+	  continue;
+	}
+      else
+	{
+	  if (opts_len < 2)
+	    return;
+	  opt_len = data[1];
+
+	  if (opt_len < 2 || opt_len > opts_len)
+	    return;
+	}
+
+      if (kind == TCP_OPTION_MSS)
+	{
+	  mss = *(u16 *) (data + 2);
+	  if (clib_net_to_host_u16 (mss) > mss_clamping)
+	    {
+	      u16 mss_value_net = clib_host_to_net_u16(mss_clamping);
+	      *sum =
+		ip_csum_update (*sum, mss, mss_value_net, ip4_header_t,
+				length);
+	      clib_memcpy_fast (data + 2, &mss_value_net, 2);
+	    }
+	  return;
+	}
+    }
+}
diff --git a/src/plugins/nat/nat.h b/src/plugins/nat/nat.h
index 8ec0c62a800..de2353889da 100644
--- a/src/plugins/nat/nat.h
+++ b/src/plugins/nat/nat.h
@@ -654,7 +654,6 @@ typedef struct snat_main_s
 
   /* TCP MSS clamping */
   u16 mss_clamping;
-  u16 mss_value_net;
 
   /* counters/gauges */
   vlib_simple_counter_main_t total_users;
diff --git a/src/plugins/nat/nat44_cli.c b/src/plugins/nat/nat44_cli.c
index ccc2eac5539..9e9751d5bc9 100644
--- a/src/plugins/nat/nat44_cli.c
+++ b/src/plugins/nat/nat44_cli.c
@@ -358,10 +358,7 @@ nat_set_mss_clamping_command_fn (vlib_main_t * vm, unformat_input_t * input,
       if (unformat (line_input, "disable"))
 	sm->mss_clamping = 0;
       else if (unformat (line_input, "%d", &mss))
-	{
-	  sm->mss_clamping = (u16) mss;
-	  sm->mss_value_net = clib_host_to_net_u16 (sm->mss_clamping);
-	}
+	sm->mss_clamping = (u16) mss;
       else
 	{
 	  error = clib_error_return (0, "unknown input '%U'",
diff --git a/src/plugins/nat/nat64_in2out.c b/src/plugins/nat/nat64_in2out.c
index 38e98340b8c..af212d3061d 100644
--- a/src/plugins/nat/nat64_in2out.c
+++ b/src/plugins/nat/nat64_in2out.c
@@ -21,6 +21,7 @@
 #include <nat/nat_inlines.h>
 #include <vnet/ip/ip6_to_ip4.h>
 #include <vnet/fib/fib_table.h>
+#include <nat/lib/nat_inlines.h>
 
 typedef struct
 {
@@ -276,7 +277,7 @@ nat64_in2out_tcp_udp (vlib_main_t * vm, vlib_buffer_t * p, u16 l4_offset,
 	  csum = ip_csum_add_even (csum, ip4->src_address.as_u32);
 	  csum = ip_csum_sub_even (csum, sport);
 	  csum = ip_csum_add_even (csum, udp->src_port);
-	  mss_clamping (nm->sm, tcp, &csum);
+	  mss_clamping (nm->sm->mss_clamping, tcp, &csum);
 	  tcp->checksum = ip_csum_fold (csum);
 
 	  nat64_tcp_session_set_state (ste, tcp, 1);
diff --git a/src/plugins/nat/nat_api.c b/src/plugins/nat/nat_api.c
index 201c9d4730d..abd1d867c47 100644
--- a/src/plugins/nat/nat_api.c
+++ b/src/plugins/nat/nat_api.c
@@ -495,10 +495,7 @@ vl_api_nat_set_mss_clamping_t_handler (vl_api_nat_set_mss_clamping_t * mp)
   int rv = 0;
 
   if (mp->enable)
-    {
-      sm->mss_clamping = ntohs (mp->mss_value);
-      sm->mss_value_net = mp->mss_value;
-    }
+    sm->mss_clamping = ntohs (mp->mss_value);
   else
     sm->mss_clamping = 0;
 
diff --git a/src/plugins/nat/nat_det_in2out.c b/src/plugins/nat/nat_det_in2out.c
index cf50805c1a3..8628fcc42f7 100644
--- a/src/plugins/nat/nat_det_in2out.c
+++ b/src/plugins/nat/nat_det_in2out.c
@@ -26,6 +26,7 @@
 #include <nat/nat.h>
 #include <nat/nat_det.h>
 #include <nat/nat_inlines.h>
+#include <nat/lib/nat_inlines.h>
 
 typedef struct
 {
@@ -438,7 +439,7 @@ VLIB_NODE_FN (snat_det_in2out_node) (vlib_main_t * vm,
 	      sum0 = ip_csum_update (sum0, old_port0, new_port0,
 				     ip4_header_t /* cheat */ ,
 				     length /* changed member */ );
-	      mss_clamping (sm, tcp0, &sum0);
+	      mss_clamping (sm->mss_clamping, tcp0, &sum0);
 	      tcp0->checksum = ip_csum_fold (sum0);
 	    }
 	  else
@@ -611,7 +612,7 @@ VLIB_NODE_FN (snat_det_in2out_node) (vlib_main_t * vm,
 	      sum1 = ip_csum_update (sum1, old_port1, new_port1,
 				     ip4_header_t /* cheat */ ,
 				     length /* changed member */ );
-	      mss_clamping (sm, tcp1, &sum1);
+	      mss_clamping (sm->mss_clamping, tcp1, &sum1);
 	      tcp1->checksum = ip_csum_fold (sum1);
 	    }
 	  else
@@ -820,7 +821,7 @@ VLIB_NODE_FN (snat_det_in2out_node) (vlib_main_t * vm,
 	      sum0 = ip_csum_update (sum0, old_port0, new_port0,
 				     ip4_header_t /* cheat */ ,
 				     length /* changed member */ );
-	      mss_clamping (sm, tcp0, &sum0);
+	      mss_clamping (sm->mss_clamping, tcp0, &sum0);
 	      tcp0->checksum = ip_csum_fold (sum0);
 	    }
 	  else
diff --git a/src/plugins/nat/nat_inlines.h b/src/plugins/nat/nat_inlines.h
index 121d2c71aaa..4dad11bed72 100644
--- a/src/plugins/nat/nat_inlines.h
+++ b/src/plugins/nat/nat_inlines.h
@@ -657,54 +657,6 @@ get_icmp_o2i_ed_key (vlib_buffer_t * b, ip4_header_t * ip0, u32 rx_fib_index,
   return 0;
 }
 
-always_inline void
-mss_clamping (snat_main_t * sm, tcp_header_t * tcp, ip_csum_t * sum)
-{
-  u8 *data;
-  u8 opt_len, opts_len, kind;
-  u16 mss;
-
-  if (!(sm->mss_clamping && tcp_syn (tcp)))
-    return;
-
-  opts_len = (tcp_doff (tcp) << 2) - sizeof (tcp_header_t);
-  data = (u8 *) (tcp + 1);
-  for (; opts_len > 0; opts_len -= opt_len, data += opt_len)
-    {
-      kind = data[0];
-
-      if (kind == TCP_OPTION_EOL)
-	break;
-      else if (kind == TCP_OPTION_NOOP)
-	{
-	  opt_len = 1;
-	  continue;
-	}
-      else
-	{
-	  if (opts_len < 2)
-	    return;
-	  opt_len = data[1];
-
-	  if (opt_len < 2 || opt_len > opts_len)
-	    return;
-	}
-
-      if (kind == TCP_OPTION_MSS)
-	{
-	  mss = *(u16 *) (data + 2);
-	  if (clib_net_to_host_u16 (mss) > sm->mss_clamping)
-	    {
-	      *sum =
-		ip_csum_update (*sum, mss, sm->mss_value_net, ip4_header_t,
-				length);
-	      clib_memcpy_fast (data + 2, &sm->mss_value_net, 2);
-	    }
-	  return;
-	}
-    }
-}
-
 /**
  * @brief Check if packet should be translated
  *