libmemif: refactor examples

- icmp_responder: responds to ICMPv4 and ARP requests
- loopback: connects two interfaces and sends a
  verification packet from master memif to slave memif
  where it is looped back
- loopback (reverse path): reverses direction of packet
  in loopback application (slave memif to master memif)

Type: refactor

Signed-off-by: Jakub Grajciar <jgrajcia@cisco.com>
Change-Id: Ie90aaa3367269408efb6c5d538ad5aa827432238
Signed-off-by: Dave Wallace <dwallacelf@gmail.com>
diff --git a/extras/libmemif/examples/common/common.h b/extras/libmemif/examples/common/common.h
new file mode 100644
index 0000000..ce4ead2
--- /dev/null
+++ b/extras/libmemif/examples/common/common.h
@@ -0,0 +1,116 @@
+/*
+ *------------------------------------------------------------------
+ * 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.
+ *------------------------------------------------------------------
+ */
+
+#ifndef _COMMON_H_
+#define _COMMON_H_
+
+#include <libmemif.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/types.h>
+
+#ifdef ICMP_DBG
+#define DBG(...)                                                              \
+  do                                                                          \
+    {                                                                         \
+      printf (APP_NAME ":%s:%d: ", __func__, __LINE__);                       \
+      printf (__VA_ARGS__);                                                   \
+      printf ("\n");                                                          \
+    }                                                                         \
+  while (0)
+#else
+#define DBG(...)
+#endif
+
+#define INFO(...)                                                             \
+  do                                                                          \
+    {                                                                         \
+      printf ("INFO: " __VA_ARGS__);                                          \
+      printf ("\n");                                                          \
+    }                                                                         \
+  while (0)
+
+/* maximum tx/rx memif buffers */
+#define MAX_MEMIF_BUFS 256
+
+struct memif_connection;
+
+typedef int (memif_packet_handler_t) (struct memif_connection *conn);
+
+typedef int (packet_generator_t) (struct memif_connection *c,
+				  uint16_t num_pkts);
+
+typedef struct memif_connection
+{
+  uint16_t index;
+  /* memif conenction handle */
+  memif_conn_handle_t conn;
+  uint8_t is_connected;
+  /* transmit queue id */
+  uint16_t tx_qid;
+  /* tx buffers */
+  memif_buffer_t *tx_bufs;
+  /* allocated tx buffers counter */
+  /* number of tx buffers pointing to shared memory */
+  uint16_t tx_buf_num;
+  /* rx buffers */
+  memif_buffer_t *rx_bufs;
+  /* allcoated rx buffers counter */
+  /* number of rx buffers pointing to shared memory */
+  uint16_t rx_buf_num;
+  memif_packet_handler_t *packet_handler;
+  /* interface ip address */
+  uint8_t ip_addr[4];
+  /* interface hw address */
+  uint8_t hw_addr[6];
+} memif_connection_t;
+
+void print_version ();
+
+int parse_ip4 (const char *input, uint8_t out[4]);
+
+int parse_mac (const char *input, uint8_t out[6]);
+
+void alloc_memif_buffers (memif_connection_t *c);
+
+void free_memif_buffers (memif_connection_t *c);
+
+void print_memif_details (memif_connection_t *c);
+
+void print_memif_rx_ring_details (memif_connection_t *c, uint16_t qid);
+
+void print_memif_tx_ring_details (memif_connection_t *c, uint16_t qid);
+
+int send_packets (memif_connection_t *conn, uint16_t qid,
+		  packet_generator_t *gen, uint32_t num_pkts,
+		  uint16_t max_pkt_size);
+
+/* Expect packets smaller than 2048b */
+int responder (memif_conn_handle_t conn, void *private_ctx, uint16_t qid);
+
+/* Expect packets smaller than 2048b */
+int responder_zero_copy (memif_conn_handle_t conn, void *private_ctx,
+			 uint16_t qid);
+
+/* reply with the same data */
+int basic_packet_handler (memif_connection_t *conn);
+
+/* ICMPv4 and ARP handler */
+int icmp_packet_handler (memif_connection_t *conn);
+
+#endif /* COMMON_H */
\ No newline at end of file