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>

7 files changed, 1168 insertions, 0 deletions

diff --git a/extras/libmemif/examples/common/common.c b/extras/libmemif/examples/common/common.c
new file mode 100644
index 00000000000..5af42eaf63b
--- /dev/null
+++ b/extras/libmemif/examples/common/common.c
@@ -0,0 +1,192 @@
+#include <common.h>
+
+void
+print_memif_ring_details (memif_connection_t *c, uint16_t qid, uint8_t is_rx)
+{
+  /* TODO: print memif shared memory details */
+}
+
+void
+print_memif_rx_ring_details (memif_connection_t *c, uint16_t qid)
+{
+  print_memif_ring_details (c, qid, /* RX */ 1);
+}
+
+void
+print_memif_tx_ring_details (memif_connection_t *c, uint16_t qid)
+{
+  print_memif_ring_details (c, qid, /* TX */ 0);
+}
+
+void
+print_version ()
+{
+  printf ("libmemif version: %s, memif version: %s\n", LIBMEMIF_VERSION,
+	  memif_get_version_str ());
+}
+
+int
+parse_ip4 (const char *input, uint8_t out[4])
+{
+  char *ui, *end;
+  char *tmp = strdup (input);
+
+  ui = strtok (tmp, ".");
+  if (ui == NULL)
+    return -1;
+  out[0] = strtol (ui, &end, 10);
+
+  ui = strtok (NULL, ".");
+  if (ui == NULL)
+    return -1;
+  out[1] = strtol (ui, &end, 10);
+
+  ui = strtok (NULL, ".");
+  if (ui == NULL)
+    return -1;
+  out[2] = strtol (ui, &end, 10);
+
+  ui = strtok (NULL, ".");
+  if (ui == NULL)
+    return -1;
+  out[3] = strtol (ui, &end, 10);
+
+  free (tmp);
+
+  return 0;
+}
+
+int
+parse_mac (const char *input, uint8_t out[6])
+{
+  char *ui, *end;
+  char *tmp = strdup (input);
+
+  ui = strtok (tmp, ":");
+  if (ui == NULL)
+    return -1;
+  out[0] = strtol (ui, &end, 16);
+  ui = strtok (NULL, ":");
+  if (ui == NULL)
+    return -1;
+  out[1] = strtol (ui, &end, 16);
+  ui = strtok (NULL, ":");
+  if (ui == NULL)
+    return -1;
+  out[2] = strtol (ui, &end, 16);
+  ui = strtok (NULL, ":");
+  if (ui == NULL)
+    return -1;
+  out[3] = strtol (ui, &end, 16);
+  ui = strtok (NULL, ":");
+  if (ui == NULL)
+    return -1;
+  out[4] = strtol (ui, &end, 16);
+  ui = strtok (NULL, ":");
+  if (ui == NULL)
+    return -1;
+  out[5] = strtol (ui, &end, 16);
+
+  free (tmp);
+
+  return 0;
+}
+
+void
+alloc_memif_buffers (memif_connection_t *c)
+{
+  c->rx_bufs =
+    (memif_buffer_t *) malloc (sizeof (memif_buffer_t) * MAX_MEMIF_BUFS);
+  c->rx_buf_num = 0;
+  c->tx_bufs =
+    (memif_buffer_t *) malloc (sizeof (memif_buffer_t) * MAX_MEMIF_BUFS);
+  c->tx_buf_num = 0;
+}
+
+void
+free_memif_buffers (memif_connection_t *c)
+{
+  if (c->rx_bufs != NULL)
+    free (c->rx_bufs);
+  c->rx_bufs = NULL;
+  c->rx_buf_num = 0;
+  if (c->tx_bufs != NULL)
+    free (c->tx_bufs);
+  c->tx_bufs = NULL;
+  c->tx_buf_num = 0;
+}
+
+void
+print_memif_details (memif_connection_t *c)
+{
+  printf ("MEMIF DETAILS\n");
+  printf ("==============================\n");
+
+  memif_details_t md;
+  memset (&md, 0, sizeof (md));
+  ssize_t buflen = 2048;
+  char *buf = (char *) malloc (buflen);
+  memset (buf, 0, buflen);
+  int err, e;
+
+  err = memif_get_details (c->conn, &md, buf, buflen);
+  if (err != MEMIF_ERR_SUCCESS)
+    {
+      INFO ("%s", memif_strerror (err));
+      if (err == MEMIF_ERR_NOCONN)
+	{
+	  free (buf);
+	  return;
+	}
+    }
+
+  printf ("\tinterface name: %s\n", (char *) md.if_name);
+  printf ("\tapp name: %s\n", (char *) md.inst_name);
+  printf ("\tremote interface name: %s\n", (char *) md.remote_if_name);
+  printf ("\tremote app name: %s\n", (char *) md.remote_inst_name);
+  printf ("\tid: %u\n", md.id);
+  printf ("\tsecret: %s\n", (char *) md.secret);
+  printf ("\trole: ");
+  if (md.role)
+    printf ("slave\n");
+  else
+    printf ("master\n");
+  printf ("\tmode: ");
+  switch (md.mode)
+    {
+    case 0:
+      printf ("ethernet\n");
+      break;
+    case 1:
+      printf ("ip\n");
+      break;
+    case 2:
+      printf ("punt/inject\n");
+      break;
+    default:
+      printf ("unknown\n");
+      break;
+    }
+  printf ("\tsocket path: %s\n", (char *) md.socket_path);
+  printf ("\trx queues:\n");
+  for (e = 0; e < md.rx_queues_num; e++)
+    {
+      printf ("\t\tqueue id: %u\n", md.rx_queues[e].qid);
+      printf ("\t\tring size: %u\n", md.rx_queues[e].ring_size);
+      printf ("\t\tbuffer size: %u\n", md.rx_queues[e].buffer_size);
+    }
+  printf ("\ttx queues:\n");
+  for (e = 0; e < md.tx_queues_num; e++)
+    {
+      printf ("\t\tqueue id: %u\n", md.tx_queues[e].qid);
+      printf ("\t\tring size: %u\n", md.tx_queues[e].ring_size);
+      printf ("\t\tbuffer size: %u\n", md.tx_queues[e].buffer_size);
+    }
+  printf ("\tlink: ");
+  if (md.link_up_down)
+    printf ("up\n");
+  else
+    printf ("down\n");
+
+  free (buf);
+}
diff --git a/extras/libmemif/examples/common/common.h b/extras/libmemif/examples/common/common.h
new file mode 100644
index 00000000000..ce4ead2d253
--- /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
diff --git a/extras/libmemif/examples/common/icmp_proto.c b/extras/libmemif/examples/common/icmp_proto.c
new file mode 100644
index 00000000000..fafc8e425b9
--- /dev/null
+++ b/extras/libmemif/examples/common/icmp_proto.c
@@ -0,0 +1,520 @@
+/*
+ *------------------------------------------------------------------
+ * Copyright (c) 2017 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 <stdint.h>
+#include <net/if.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/uio.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <inttypes.h>
+#include <string.h>
+#include <stdio.h>
+#include <netdb.h>
+#include <linux/ip.h>
+#include <linux/icmp.h>
+#include <arpa/inet.h>
+#include <stdlib.h>
+#include <netinet/if_ether.h>
+#include <net/if_arp.h>
+#include <asm/byteorder.h>
+#include <byteswap.h>
+#include <assert.h>
+
+#include <icmp_proto.h>
+
+static uint16_t
+cksum (void *addr, ssize_t len)
+{
+  char *data = (char *) addr;
+
+  uint32_t acc = 0xffff;
+
+  ssize_t i;
+  for (i = 0; (i + 1) < len; i += 2)
+    {
+      uint16_t word;
+      memcpy (&word, data + i, 2);
+      acc += ntohs (word);
+      if (acc > 0xffff)
+	acc -= 0xffff;
+    }
+
+  if (len & 1)
+    {
+      uint16_t word = 0;
+      memcpy (&word, data + len - 1, 1);
+      acc += ntohs (word);
+      if (acc > 0xffff)
+	acc -= 0xffff;
+    }
+  return htons (~acc);
+}
+
+int
+print_packet (void *pck)
+{
+  if (pck == NULL)
+    {
+      printf ("ICMP_PROTO: no data\n");
+      return -1;
+    }
+  struct iphdr *ip;
+  struct icmphdr *icmp;
+  ip = (struct iphdr *) pck;
+  icmp = (struct icmphdr *) (pck + sizeof (struct iphdr));
+  printf ("received packet:\n");
+  printf ("\tiphdr:\n");
+  printf ("\t\tihl: %u\n\t\tversion: %u\n\t\tlen: %u\n\t\tid: %u\n", ip->ihl,
+	  ip->version, __bswap_16 (ip->tot_len), ip->id);
+  printf ("\t\tprotocol: %u\n", ip->protocol);
+
+  printf ("\t\tsaddr: ");
+  int i;
+  for (i = 0; i < 4; i++)
+    {
+      printf ("%u.", ((uint8_t *) &ip->saddr)[i]);
+    }
+  printf ("\n");
+
+  printf ("\t\tdaddr: ");
+  for (i = 0; i < 4; i++)
+    {
+      printf ("%u.", ((uint8_t *) &ip->daddr)[i]);
+    }
+  printf ("\n");
+  printf ("\ticmphdr:\n");
+  printf ("\t\ttype: %s\n",
+	  (icmp->type == ICMP_ECHO) ? "ICMP_ECHO" : "ICMP_ECHOREPLY");
+
+  return 0;
+}
+
+static ssize_t
+resolve_arp (void *arp)
+{
+  struct arphdr *resp = (struct arphdr *) arp;
+
+  resp->ar_hrd = __bswap_16 (ARPHRD_ETHER);
+
+  resp->ar_pro = __bswap_16 (0x0800);
+
+  resp->ar_hln = 6;
+  resp->ar_pln = 4;
+
+  resp->ar_op = __bswap_16 (ARPOP_REPLY);
+
+  return sizeof (struct arphdr);
+}
+
+static ssize_t
+resolve_eth_arp (struct ether_arp *eth_arp, void *eth_arp_resp,
+		 uint8_t ip_addr[4])
+{
+  struct ether_arp *resp = (struct ether_arp *) eth_arp_resp;
+
+  resolve_arp (&resp->ea_hdr);
+
+  memcpy (resp->arp_tha, eth_arp->arp_sha, 6);
+  memcpy (resp->arp_tpa, eth_arp->arp_spa, 4);
+
+  memcpy (
+    resp->arp_sha,
+    (((struct ether_header *) (eth_arp_resp - sizeof (struct ether_header)))
+       ->ether_shost),
+    6);
+
+  memcpy (resp->arp_spa, ip_addr, 4);
+
+  return sizeof (struct ether_arp);
+}
+
+static ssize_t
+resolve_eth (struct ether_header *eth, void *eth_resp, uint8_t hw_addr[6])
+{
+  struct ether_header *resp = (struct ether_header *) eth_resp;
+  memcpy (resp->ether_dhost, eth->ether_shost, 6);
+
+  memcpy (resp->ether_shost, hw_addr, 6);
+
+  resp->ether_type = eth->ether_type;
+
+  return sizeof (struct ether_header);
+}
+
+static ssize_t
+resolve_ip (struct iphdr *ip, void *ip_resp, uint8_t ip_addr[4])
+{
+  struct iphdr *resp = (struct iphdr *) ip_resp;
+  resp->ihl = 5;
+  resp->version = 4;
+  resp->tos = 0;
+  /*len updated later */
+  resp->tot_len = 0x0000;
+  resp->id = 0;
+  resp->frag_off = 0;
+  resp->ttl = 0x40;
+  resp->protocol = 1;
+  ((uint8_t *) &resp->saddr)[0] = ip_addr[0];
+  ((uint8_t *) &resp->saddr)[1] = ip_addr[1];
+  ((uint8_t *) &resp->saddr)[2] = ip_addr[2];
+  ((uint8_t *) &resp->saddr)[3] = ip_addr[3];
+  resp->daddr = ip->saddr;
+
+  /* resp->check =  cksum (resp, sizeof (struct iphdr)); */
+
+  return sizeof (struct iphdr);
+}
+
+static ssize_t
+resolve_icmp (struct icmphdr *icmp, void *icmp_resp)
+{
+  struct icmphdr *resp = (struct icmphdr *) icmp_resp;
+  resp->type = 0x00;
+  resp->code = 0;
+  resp->un.echo.id = icmp->un.echo.id;
+  resp->un.echo.sequence = icmp->un.echo.sequence;
+
+  /*resp->checksum = cksum (resp, sizeof (struct icmphdr)); */
+
+  return sizeof (struct icmphdr);
+}
+
+int
+resolve_packet (void *in_pck, ssize_t in_size, void *out_pck,
+		uint32_t *out_size, uint8_t ip_addr[4], uint8_t hw_addr[6])
+{
+  struct ether_header *eh;
+  struct ether_arp *eah;
+  struct iphdr *ip, *ip_out;
+  struct icmphdr *icmp;
+  *out_size = 0;
+
+  if ((in_pck == NULL) || (out_pck == NULL))
+    return -1;
+
+  eh = (struct ether_header *) in_pck;
+  *out_size = resolve_eth (eh, out_pck, hw_addr);
+
+  if (eh->ether_type == 0x0608)
+    {
+      eah = (struct ether_arp *) (in_pck + *out_size);
+      *out_size += resolve_eth_arp (eah, out_pck + *out_size, ip_addr);
+    }
+  else if (eh->ether_type == 0x0008)
+    {
+#ifdef ICMP_DBG
+      print_packet (in_pck + *out_size);
+#endif
+      ip = (struct iphdr *) (in_pck + *out_size);
+      ip_out = (struct iphdr *) (out_pck + *out_size);
+      *out_size += resolve_ip (ip, out_pck + *out_size, ip_addr);
+      if (ip->protocol == 1)
+	{
+	  icmp = (struct icmphdr *) (in_pck + *out_size);
+	  *out_size += resolve_icmp (icmp, out_pck + *out_size);
+	  ((struct icmphdr *) (out_pck + *out_size - sizeof (struct icmphdr)))
+	    ->checksum = cksum (out_pck + *out_size - sizeof (struct icmphdr),
+				sizeof (struct icmphdr));
+	  /* payload */
+	  memcpy (out_pck + *out_size, in_pck + *out_size,
+		  in_size - *out_size);
+	  *out_size = in_size;
+	  ip_out->tot_len =
+	    __bswap_16 (*out_size - sizeof (struct ether_header));
+	  ip_out->check = cksum (ip_out, sizeof (struct iphdr));
+	}
+    }
+  return 0;
+}
+
+static ssize_t
+generate_eth (struct ether_header *eh, uint8_t hw_daddr[6])
+{
+  uint8_t hw_addr[6];
+  int i;
+  for (i = 0; i < 6; i++)
+    {
+      hw_addr[i] = 'a';
+    }
+  memcpy (eh->ether_shost, hw_addr, 6);
+  memcpy (eh->ether_dhost, hw_daddr, 6);
+
+  eh->ether_type = 0x0008;
+
+  return sizeof (struct ether_header);
+}
+
+static ssize_t
+generate_ip (struct iphdr *ip, uint8_t saddr[4], uint8_t daddr[4])
+{
+  ip->ihl = 5;
+  ip->version = 4;
+  ip->tos = 0;
+  /*len updated later */
+  ip->tot_len = 0x5400;
+  ip->id = 0;
+  ip->frag_off = 0;
+  ip->ttl = 0x40;
+  ip->protocol = 1;
+  /* saddr */
+  ((uint8_t *) &ip->saddr)[0] = saddr[0];
+  ((uint8_t *) &ip->saddr)[1] = saddr[1];
+  ((uint8_t *) &ip->saddr)[2] = saddr[2];
+  ((uint8_t *) &ip->saddr)[3] = saddr[3];
+  /* daddr */
+  ((uint8_t *) &ip->daddr)[0] = daddr[0];
+  ((uint8_t *) &ip->daddr)[1] = daddr[1];
+  ((uint8_t *) &ip->daddr)[2] = daddr[2];
+  ((uint8_t *) &ip->daddr)[3] = daddr[3];
+
+  ip->check = cksum (ip, sizeof (struct iphdr));
+
+  return sizeof (struct iphdr);
+}
+
+static ssize_t
+generate_icmp (struct icmphdr *icmp, uint32_t seq)
+{
+  icmp->type = ICMP_ECHO;
+  icmp->code = 0;
+  icmp->un.echo.id = 0;
+  icmp->un.echo.sequence = seq;
+
+  return sizeof (struct icmphdr);
+}
+
+int
+generate_packet (void *pck, uint32_t *size, uint8_t saddr[4], uint8_t daddr[4],
+		 uint8_t hw_daddr[6], uint32_t seq)
+{
+  struct ether_header *eh;
+  struct iphdr *ip;
+  struct icmphdr *icmp;
+
+  *size = 0;
+
+  eh = (struct ether_header *) pck;
+  *size += generate_eth (eh, hw_daddr);
+
+  ip = (struct iphdr *) (pck + *size);
+  *size += generate_ip (ip, saddr, daddr);
+
+  icmp = (struct icmphdr *) (pck + *size);
+  *size += generate_icmp (icmp, seq);
+
+  ((struct icmphdr *) (pck + *size - sizeof (struct icmphdr)))->checksum =
+    cksum (pck + *size - sizeof (struct icmphdr), sizeof (struct icmphdr));
+
+  ip->tot_len = __bswap_16 (*size - sizeof (struct ether_header));
+  ip->check = 0;
+  ip->check = cksum (ip, sizeof (struct iphdr));
+
+  return 0;
+}
+
+int
+generate_packet2 (void *pck, uint32_t *size, uint8_t saddr[4],
+		  uint8_t daddr[4], uint8_t hw_daddr[6], uint32_t seq,
+		  icmpr_flow_mode_t mode)
+{
+  struct ether_header *eh;
+  struct iphdr *ip;
+  struct icmphdr *icmp;
+
+  *size = 0;
+
+  if (mode == ICMPR_FLOW_MODE_ETH)
+    {
+      eh = (struct ether_header *) pck;
+      *size += generate_eth (eh, hw_daddr);
+    }
+
+  ip = (struct iphdr *) (pck + *size);
+  *size += generate_ip (ip, saddr, daddr);
+
+  icmp = (struct icmphdr *) (pck + *size);
+  *size += generate_icmp (icmp, seq);
+
+  ((struct icmphdr *) (pck + *size - sizeof (struct icmphdr)))->checksum =
+    cksum (pck + *size - sizeof (struct icmphdr), sizeof (struct icmphdr));
+
+  ip->tot_len = __bswap_16 (*size - sizeof (struct ether_header));
+  ip->check = 0;
+  ip->check = cksum (ip, sizeof (struct iphdr));
+
+  return 0;
+}
+
+#define GET_HEADER(out, hdr, src, off)                                        \
+  do                                                                          \
+    {                                                                         \
+      out = (hdr *) (src + off);                                              \
+      off += sizeof (hdr);                                                    \
+    }                                                                         \
+  while (0)
+
+int
+resolve_packet_zero_copy (void *pck, uint32_t *size, uint8_t ip_addr[4],
+			  uint8_t hw_addr[6])
+{
+  struct ether_header *eh;
+  struct ether_arp *eah;
+  struct iphdr *ip;
+  struct icmphdr *icmp;
+  uint32_t offset = 0;
+
+  if (pck == NULL)
+    return 0;
+
+  GET_HEADER (eh, struct ether_header, pck, offset);
+
+  memcpy (eh->ether_dhost, eh->ether_shost, 6);
+  memcpy (eh->ether_shost, hw_addr, 6);
+
+  if (eh->ether_type == 0x0608)
+    {
+      GET_HEADER (eah, struct ether_arp, pck, offset);
+      struct arphdr *arp = &eah->ea_hdr;
+
+      arp->ar_hrd = __bswap_16 (ARPHRD_ETHER);
+      arp->ar_pro = __bswap_16 (0x0800);
+
+      arp->ar_hln = 6;
+      arp->ar_pln = 4;
+
+      arp->ar_op = __bswap_16 (ARPOP_REPLY);
+
+      memcpy (eah->arp_tha, eah->arp_sha, 6);
+      memcpy (eah->arp_tpa, eah->arp_spa, 4);
+
+      memcpy (eah->arp_sha, eh->ether_shost, 6);
+      memcpy (eah->arp_spa, ip_addr, 4);
+    }
+
+  else if (eh->ether_type == 0x0008)
+    {
+      GET_HEADER (ip, struct iphdr, pck, offset);
+
+      if (ip->protocol == 1)
+	{
+	  ip->ihl = 5;
+	  ip->version = 4;
+	  ip->tos = 0;
+	  ip->tot_len = 0x0000;
+	  ip->id = 0;
+	  ip->frag_off = 0;
+	  ip->ttl = 0x40;
+	  ip->protocol = 1;
+	  ip->check = 0x0000;
+	  ip->daddr = ip->saddr;
+	  ((uint8_t *) &ip->saddr)[0] = ip_addr[0];
+	  ((uint8_t *) &ip->saddr)[1] = ip_addr[1];
+	  ((uint8_t *) &ip->saddr)[2] = ip_addr[2];
+	  ((uint8_t *) &ip->saddr)[3] = ip_addr[3];
+
+	  GET_HEADER (icmp, struct icmphdr, pck, offset);
+
+	  icmp->type = 0x00;
+	  icmp->code = 0;
+	  icmp->checksum = cksum (icmp, sizeof (struct icmphdr));
+
+	  /* rest is payload */
+	  offset = *size;
+
+	  ip->tot_len = __bswap_16 (offset - sizeof (struct ether_header));
+	  ip->check = cksum (ip, sizeof (struct iphdr));
+	}
+    }
+
+  assert (offset == *size && "unsupported protocol");
+  return 0;
+}
+
+int
+resolve_packet_zero_copy_add_encap (void **pck_, uint32_t *size,
+				    uint8_t ip_addr[4])
+{
+  struct ether_header *eh;
+  struct iphdr *ip;
+  struct icmphdr *icmp;
+  int32_t offset = 0;
+  uint16_t encap_size = sizeof (struct ether_header);
+  void *pck = *pck_;
+
+  if (pck == NULL)
+    return 0;
+
+  *pck_ -= encap_size;
+  offset -= encap_size;
+
+  GET_HEADER (eh, struct ether_header, pck, offset);
+
+  uint8_t hw_daddr[6];
+  memset (hw_daddr, 0, sizeof (uint8_t) * 6);
+
+  generate_eth (eh, hw_daddr);
+
+  if (eh->ether_type == 0x0008)
+    {
+      GET_HEADER (ip, struct iphdr, pck, offset);
+
+      if (ip->protocol == 1)
+	{
+	  ip->ihl = 5;
+	  ip->version = 4;
+	  ip->tos = 0;
+	  ip->tot_len = 0x0000;
+	  ip->id = 0;
+	  ip->frag_off = 0;
+	  ip->ttl = 0x40;
+	  ip->protocol = 1;
+	  ip->check = 0x0000;
+	  ip->daddr = ip->saddr;
+	  ((uint8_t *) &ip->saddr)[0] = ip_addr[0];
+	  ((uint8_t *) &ip->saddr)[1] = ip_addr[1];
+	  ((uint8_t *) &ip->saddr)[2] = ip_addr[2];
+	  ((uint8_t *) &ip->saddr)[3] = ip_addr[3];
+
+	  GET_HEADER (icmp, struct icmphdr, pck, offset);
+
+	  icmp->type = 0x00;
+	  icmp->code = 0;
+	  icmp->checksum = cksum (icmp, sizeof (struct icmphdr));
+
+	  /* rest is payload */
+	  offset = *size;
+
+	  ip->tot_len = __bswap_16 (offset - sizeof (struct ether_header));
+	  ip->check = cksum (ip, sizeof (struct iphdr));
+	}
+    }
+
+  offset += encap_size;
+
+  assert (offset != *size &&
+	  "new packet length must be increased by encap size");
+
+  /* overwrite packet size */
+  *size = offset;
+
+  return 0;
+}
diff --git a/extras/libmemif/examples/common/icmp_proto.h b/extras/libmemif/examples/common/icmp_proto.h
new file mode 100644
index 00000000000..e346a3b13f7
--- /dev/null
+++ b/extras/libmemif/examples/common/icmp_proto.h
@@ -0,0 +1,48 @@
+/*
+ *------------------------------------------------------------------
+ * Copyright (c) 2017 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 _ICMP_PROTO_H_
+#define _ICMP_PROTO_H_
+
+typedef enum
+{
+  ICMPR_FLOW_MODE_ETH = 0,
+  ICMPR_FLOW_MODE_IP,
+} icmpr_flow_mode_t;
+
+int resolve_packet (void *in_pck, ssize_t in_size, void *out_pck,
+		    uint32_t *out_size, uint8_t ip_addr[4],
+		    uint8_t hw_addr[6]);
+
+/* resolve packet in place */
+int resolve_packet_zero_copy (void *pck, uint32_t *size, uint8_t ip_addr[4],
+			      uint8_t hw_addr[6]);
+
+/* resolve packet in place and add eth encap */
+int resolve_packet_zero_copy_add_encap (void **pck, uint32_t *size,
+					uint8_t ip_addr[4]);
+
+int generate_packet (void *pck, uint32_t *size, uint8_t saddr[4],
+		     uint8_t daddr[4], uint8_t hw_daddr[6], uint32_t seq);
+
+int generate_packet2 (void *pck, uint32_t *size, uint8_t saddr[4],
+		      uint8_t daddr[4], uint8_t hw_daddr[6], uint32_t seq,
+		      icmpr_flow_mode_t);
+
+int print_packet (void *pck);
+
+#endif /* _ICMP_PROTO_H_ */
diff --git a/extras/libmemif/examples/common/packet_handler.c b/extras/libmemif/examples/common/packet_handler.c
new file mode 100644
index 00000000000..705cc728a36
--- /dev/null
+++ b/extras/libmemif/examples/common/packet_handler.c
@@ -0,0 +1,65 @@
+/*
+ *------------------------------------------------------------------
+ * 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 <common.h>
+#include <icmp_proto.h>
+
+/* reply with the same data */
+int
+basic_packet_handler (memif_connection_t *c)
+{
+  int i;
+  memif_buffer_t *dest, *src;
+
+  /* in case of zero-copy the tx_buf_num will be zero, so the loop body won't
+   * execute */
+  for (i = 0; i < c->tx_buf_num; i++)
+    {
+      memcpy (c->tx_bufs[i].data, c->rx_bufs[i].data, c->rx_bufs[i].len);
+    }
+
+  return 0;
+}
+
+/* ICMPv4 and ARP handler */
+int
+icmp_packet_handler (memif_connection_t *c)
+{
+  int i;
+  memif_buffer_t *dest, *src;
+
+  /* if tx_buf_num > 0 we use non-zero-copy mode */
+  if (c->tx_buf_num > 0)
+    {
+      for (i = 0; i < c->tx_buf_num; i++)
+	{
+	  resolve_packet (c->rx_bufs[i].data, c->rx_bufs[i].len,
+			  c->tx_bufs[i].data, &c->tx_bufs[i].len, c->ip_addr,
+			  c->hw_addr);
+	}
+    }
+  else
+    {
+      for (i = 0; i < c->rx_buf_num; i++)
+	{
+	  resolve_packet_zero_copy (c->rx_bufs[i].data, &c->rx_bufs[i].len,
+				    c->ip_addr, c->hw_addr);
+	}
+    }
+
+  return 0;
+}
\ No newline at end of file
diff --git a/extras/libmemif/examples/common/responder.c b/extras/libmemif/examples/common/responder.c
new file mode 100644
index 00000000000..e0fa9e35b08
--- /dev/null
+++ b/extras/libmemif/examples/common/responder.c
@@ -0,0 +1,172 @@
+#include <common.h>
+
+int
+responder (memif_conn_handle_t conn, void *private_ctx, uint16_t qid)
+{
+  memif_connection_t *c = (memif_connection_t *) private_ctx;
+  int err, i;
+  uint16_t tx;
+
+  /* receive packets from the shared memory */
+  err = memif_rx_burst (conn, qid, c->rx_bufs, MAX_MEMIF_BUFS, &c->rx_buf_num);
+  if (err != MEMIF_ERR_SUCCESS)
+    {
+      INFO ("memif_rx_burst: %s", memif_strerror (err));
+      return err;
+    }
+
+  do
+    {
+      /* allocate tx buffers */
+      err = memif_buffer_alloc (conn, qid, c->tx_bufs, c->rx_buf_num,
+				&c->tx_buf_num, 2048);
+      /* suppress full ring error MEMIF_ERR_NOBUF_RING */
+      if (err != MEMIF_ERR_SUCCESS && err != MEMIF_ERR_NOBUF_RING)
+	{
+	  INFO ("memif_buffer_alloc: %s", memif_strerror (err));
+	  goto error;
+	}
+
+      /* Process the packets */
+      if (c->packet_handler == NULL)
+	{
+	  INFO ("Missing packet handler");
+	  goto error;
+	}
+      err = c->packet_handler (c);
+      if (err != 0)
+	{
+	  INFO ("packet handler error: %d", err);
+	  goto error;
+	}
+      /* Done processing packets */
+
+      /* refill the queue */
+      err = memif_refill_queue (conn, qid, c->tx_buf_num, 0);
+      if (err != MEMIF_ERR_SUCCESS)
+	{
+	  INFO ("memif_refill_queue: %s", memif_strerror (err));
+	  goto error;
+	}
+      c->rx_buf_num -= c->tx_buf_num;
+
+      err = memif_tx_burst (conn, qid, c->tx_bufs, c->tx_buf_num, &tx);
+      if (err != MEMIF_ERR_SUCCESS)
+	{
+	  INFO ("memif_tx_burst: %s", memif_strerror (err));
+	  goto error;
+	}
+      c->tx_buf_num -= tx;
+
+      /* This should never happen */
+      if (c->tx_buf_num != 0)
+	{
+	  INFO ("memif_tx_burst failed to send all allocated buffers.");
+	  goto error;
+	}
+    }
+  while (c->rx_buf_num > 0);
+
+  return 0;
+
+error:
+  err = memif_refill_queue (conn, qid, c->rx_buf_num, 0);
+  if (err != MEMIF_ERR_SUCCESS)
+    {
+      INFO ("memif_refill_queue: %s", memif_strerror (err));
+      return err;
+    }
+  c->rx_buf_num = 0;
+
+  return -1;
+}
+
+int
+responder_zero_copy (memif_conn_handle_t conn, void *private_ctx, uint16_t qid)
+{
+  memif_connection_t *c = (memif_connection_t *) private_ctx;
+  int err, i;
+  uint16_t tx, tx2;
+
+  /* receive packets from the shared memory */
+  err = memif_rx_burst (conn, qid, c->rx_bufs, MAX_MEMIF_BUFS, &c->rx_buf_num);
+  if (err != MEMIF_ERR_SUCCESS)
+    {
+      INFO ("memif_rx_burst: %s", memif_strerror (err));
+      return err;
+    }
+
+  do
+    {
+      /* Note that in zero copy memif_buffer_alloc is not part of respond
+      process,
+       * instead rx buffers are used directly using memif_buffer_enq_tx.
+       * /
+
+      /* Process the packets */
+      if (c->packet_handler == NULL)
+	{
+	  INFO ("Missing packet handler");
+	  goto error;
+	}
+      err = c->packet_handler (c);
+      if (err != 0)
+	{
+	  INFO ("packet handler error: %d", err);
+	  goto error;
+	}
+      /* Done processing packets */
+
+      /* Swap rx and tx buffers, swapped tx buffers are considered allocated
+       * and are ready to be transmitted. Notice that the buffers are swapped
+       * only in memif driver and locally remain in rx_bufs queue.
+       */
+      err = memif_buffer_enq_tx (conn, qid, c->rx_bufs, c->rx_buf_num, &tx);
+      /* suppress full ring error MEMIF_ERR_NOBUF_RING */
+      if (err != MEMIF_ERR_SUCCESS && err != MEMIF_ERR_NOBUF_RING)
+	{
+	  INFO ("memif_buffer_alloc: %s", memif_strerror (err));
+	  goto error;
+	}
+
+      /* refill the queue */
+      err = memif_refill_queue (conn, qid, tx, 0);
+      if (err != MEMIF_ERR_SUCCESS)
+	{
+	  INFO ("memif_refill_queue: %s", memif_strerror (err));
+	  goto error;
+	}
+      c->rx_buf_num -= tx;
+
+      /* Notice that we send from rx_bufs as the buffers were only swapped
+       * internally in memif driver */
+      err = memif_tx_burst (conn, qid, c->rx_bufs, tx, &tx2);
+      if (err != MEMIF_ERR_SUCCESS)
+	{
+	  INFO ("memif_tx_burst: %s", memif_strerror (err));
+	  goto error;
+	}
+      tx -= tx2;
+
+      /* This should never happen */
+      if (tx != 0)
+	{
+	  INFO ("memif_tx_burst failed to send all allocated buffers.");
+	  goto error;
+	}
+    }
+  while (c->rx_buf_num > 0);
+
+  return 0;
+
+error:
+  err = memif_refill_queue (conn, qid, c->rx_buf_num, 0);
+  if (err != MEMIF_ERR_SUCCESS)
+    {
+      INFO ("memif_refill_queue: %s", memif_strerror (err));
+      return err;
+    }
+  c->rx_buf_num = 0;
+
+  return -1;
+}
\ No newline at end of file
diff --git a/extras/libmemif/examples/common/sender.c b/extras/libmemif/examples/common/sender.c
new file mode 100644
index 00000000000..bad926f7a16
--- /dev/null
+++ b/extras/libmemif/examples/common/sender.c
@@ -0,0 +1,55 @@
+#include <common.h>
+
+int
+send_packets (memif_connection_t *c, uint16_t qid,
+	      packet_generator_t *generator, uint32_t num_pkts,
+	      uint16_t max_pkt_size)
+{
+  int err, i;
+  uint16_t tx;
+
+  do
+    {
+      err = memif_buffer_alloc (c->conn, qid, c->tx_bufs,
+				num_pkts > MAX_MEMIF_BUFS ? MAX_MEMIF_BUFS :
+								  num_pkts,
+				&c->tx_buf_num, max_pkt_size);
+      /* suppress full ring error MEMIF_ERR_NOBUF_RING */
+      if (err != MEMIF_ERR_SUCCESS && err != MEMIF_ERR_NOBUF_RING)
+	{
+	  INFO ("memif_buffer_alloc: %s", memif_strerror (err));
+	  goto error;
+	}
+
+      /* generate packet inside allocated buffers */
+      err = generator (c, num_pkts);
+      if (err != 0)
+	{
+	  INFO ("paclet generator error: %d", err);
+	  goto error;
+	}
+
+      err = memif_tx_burst (c->conn, qid, c->tx_bufs, c->tx_buf_num, &tx);
+      if (err != MEMIF_ERR_SUCCESS)
+	{
+	  INFO ("memif_tx_burst: %s", memif_strerror (err));
+	  goto error;
+	}
+      c->tx_buf_num -= tx;
+
+      /* Should never happen... */
+      if (c->tx_buf_num > 0)
+	{
+	  INFO ("Failed to send allocated packets");
+	  goto error;
+	}
+      num_pkts -= tx;
+    }
+  while (num_pkts > 0);
+
+  return 0;
+
+error:
+  /* TODO: free alloocated tx buffers */
+  return -1;
+}
\ No newline at end of file