+enum ip_local_packet_type_e
+{
+ IP_LOCAL_PACKET_TYPE_L4,
+ IP_LOCAL_PACKET_TYPE_NAT,
+ IP_LOCAL_PACKET_TYPE_FRAG,
+};
+
+/**
+ * Determine packet type and next node.
+ *
+ * The expectation is that all packets that are not L4 will skip
+ * checksums and source checks.
+ */
+always_inline u8
+ip4_local_classify (vlib_buffer_t * b, ip4_header_t * ip, u16 * next)
+{
+ ip_lookup_main_t *lm = &ip4_main.lookup_main;
+
+ if (PREDICT_FALSE (ip4_is_fragment (ip)))
+ {
+ *next = IP_LOCAL_NEXT_REASSEMBLY;
+ return IP_LOCAL_PACKET_TYPE_FRAG;
+ }
+ if (PREDICT_FALSE (b->flags & VNET_BUFFER_F_IS_NATED))
+ {
+ *next = lm->local_next_by_ip_protocol[ip->protocol];
+ return IP_LOCAL_PACKET_TYPE_NAT;
+ }
+
+ *next = lm->local_next_by_ip_protocol[ip->protocol];
+ return IP_LOCAL_PACKET_TYPE_L4;
+}
+