nat: fix dhcp client on outside interface with output feature

When a DHCP client is configured on a NAT outside interface with
output feature enabled, DHCP packets will reach the NAT in2out-output
node and will be dropped with "out of ports" reason.

With this commit, allow locally originated DHCP packets to be sent
from a NAT outside interface with output feature enabled.

Type: fix

Change-Id: I47d76b22587f2bf0c7b0b9dfda41c89f8f61d0b4
Signed-off-by: Alexander Chernavin <achernavin@netgate.com>

3 files changed, 87 insertions, 0 deletions

diff --git a/src/plugins/dhcp/client.c b/src/plugins/dhcp/client.c
index 105c744a147..f6205b6b0a0 100644
--- a/src/plugins/dhcp/client.c
+++ b/src/plugins/dhcp/client.c
@@ -516,6 +516,7 @@ send_dhcp_pkt (dhcp_client_main_t * dcm, dhcp_client_t * c,
   ASSERT (b->current_data == 0);
 
   vnet_buffer (b)->sw_if_index[VLIB_RX] = c->sw_if_index;
+  b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
 
   if (ADJ_INDEX_INVALID == c->ai_ucast)
     is_broadcast = 1;
diff --git a/src/plugins/nat/in2out.c b/src/plugins/nat/in2out.c
index 5cfe058c099..f3878dbbe30 100755
--- a/src/plugins/nat/in2out.c
+++ b/src/plugins/nat/in2out.c
@@ -24,6 +24,7 @@
 #include <vnet/ip/ip.h>
 #include <vnet/ethernet/ethernet.h>
 #include <vnet/fib/ip4_fib.h>
+#include <vnet/udp/udp.h>
 #include <nat/nat.h>
 #include <nat/nat_ipfix_logging.h>
 #include <nat/nat_reass.h>
@@ -1032,6 +1033,18 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 									   thread_index,
 									   sw_if_index0)))
 			goto trace00;
+
+		      /*
+		       * Send DHCP packets to the ipv4 stack, or we won't
+		       * be able to use dhcp client on the outside interface
+		       */
+		      if (PREDICT_FALSE
+			  ((b0->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED)
+			   && proto0 == SNAT_PROTOCOL_UDP
+			   && (udp0->dst_port ==
+			       clib_host_to_net_u16
+			       (UDP_DST_PORT_dhcp_to_server))))
+			goto trace00;
 		    }
 		  else
 		    {
@@ -1228,6 +1241,18 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 									   thread_index,
 									   sw_if_index1)))
 			goto trace01;
+
+		      /*
+		       * Send DHCP packets to the ipv4 stack, or we won't
+		       * be able to use dhcp client on the outside interface
+		       */
+		      if (PREDICT_FALSE
+			  ((b1->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED)
+			   && proto1 == SNAT_PROTOCOL_UDP
+			   && (udp1->dst_port ==
+			       clib_host_to_net_u16
+			       (UDP_DST_PORT_dhcp_to_server))))
+			goto trace01;
 		    }
 		  else
 		    {
@@ -1458,6 +1483,18 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 									   thread_index,
 									   sw_if_index0)))
 			goto trace0;
+
+		      /*
+		       * Send DHCP packets to the ipv4 stack, or we won't
+		       * be able to use dhcp client on the outside interface
+		       */
+		      if (PREDICT_FALSE
+			  ((b0->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED)
+			   && proto0 == SNAT_PROTOCOL_UDP
+			   && (udp0->dst_port ==
+			       clib_host_to_net_u16
+			       (UDP_DST_PORT_dhcp_to_server))))
+			goto trace0;
 		    }
 		  else
 		    {
diff --git a/src/plugins/nat/in2out_ed.c b/src/plugins/nat/in2out_ed.c
index 733e4f0c0e5..2d2be5c3812 100644
--- a/src/plugins/nat/in2out_ed.c
+++ b/src/plugins/nat/in2out_ed.c
@@ -23,6 +23,7 @@
 #include <vnet/ip/ip.h>
 #include <vnet/ethernet/ethernet.h>
 #include <vnet/fib/ip4_fib.h>
+#include <vnet/udp/udp.h>
 #include <vppinfra/error.h>
 #include <nat/nat.h>
 #include <nat/nat_ipfix_logging.h>
@@ -1005,6 +1006,18 @@ nat44_ed_in2out_node_fn_inline (vlib_main_t * vm,
 			    udp0->dst_port, thread_index, sw_if_index0,
 			    vnet_buffer (b0)->sw_if_index[VLIB_TX])))
 			goto trace00;
+
+		      /*
+		       * Send DHCP packets to the ipv4 stack, or we won't
+		       * be able to use dhcp client on the outside interface
+		       */
+		      if (PREDICT_FALSE
+			  ((b0->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED)
+			   && proto0 == SNAT_PROTOCOL_UDP
+			   && (udp0->dst_port ==
+			       clib_host_to_net_u16
+			       (UDP_DST_PORT_dhcp_to_server))))
+			goto trace00;
 		    }
 		  else
 		    {
@@ -1228,6 +1241,18 @@ nat44_ed_in2out_node_fn_inline (vlib_main_t * vm,
 			    udp1->dst_port, thread_index, sw_if_index1,
 			    vnet_buffer (b1)->sw_if_index[VLIB_TX])))
 			goto trace01;
+
+		      /*
+		       * Send DHCP packets to the ipv4 stack, or we won't
+		       * be able to use dhcp client on the outside interface
+		       */
+		      if (PREDICT_FALSE
+			  ((b1->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED)
+			   && proto1 == SNAT_PROTOCOL_UDP
+			   && (udp1->dst_port ==
+			       clib_host_to_net_u16
+			       (UDP_DST_PORT_dhcp_to_server))))
+			goto trace01;
 		    }
 		  else
 		    {
@@ -1495,6 +1520,18 @@ nat44_ed_in2out_node_fn_inline (vlib_main_t * vm,
 			    udp0->dst_port, thread_index, sw_if_index0,
 			    vnet_buffer (b0)->sw_if_index[VLIB_TX])))
 			goto trace0;
+
+		      /*
+		       * Send DHCP packets to the ipv4 stack, or we won't
+		       * be able to use dhcp client on the outside interface
+		       */
+		      if (PREDICT_FALSE
+			  ((b0->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED)
+			   && proto0 == SNAT_PROTOCOL_UDP
+			   && (udp0->dst_port ==
+			       clib_host_to_net_u16
+			       (UDP_DST_PORT_dhcp_to_server))))
+			goto trace0;
 		    }
 		  else
 		    {
@@ -1796,6 +1833,18 @@ nat44_ed_in2out_reass_node_fn_inline (vlib_main_t * vm,
 						   &fragments_to_loopback);
 			  goto trace0;
 			}
+
+		      /*
+		       * Send DHCP packets to the ipv4 stack, or we won't
+		       * be able to use dhcp client on the outside interface
+		       */
+		      if (PREDICT_FALSE
+			  ((b0->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED)
+			   && proto0 == SNAT_PROTOCOL_UDP
+			   && (udp0->dst_port ==
+			       clib_host_to_net_u16
+			       (UDP_DST_PORT_dhcp_to_server))))
+			goto trace0;
 		    }
 		  else
 		    {