Shared memory packet interface (memif) library

Change-Id: I5097462ae85acd705f19e92517c01094dba7565f
Signed-off-by: Jakub Grajciar <grajciar.jakub@gmail.com>

1 files changed, 246 insertions, 0 deletions

diff --git a/extras/libmemif/examples/icmp_responder/icmp_proto.c b/extras/libmemif/examples/icmp_responder/icmp_proto.c
new file mode 100644
index 00000000000..a923f209126
--- /dev/null
+++ b/extras/libmemif/examples/icmp_responder/icmp_proto.c
@@ -0,0 +1,246 @@
+/*
+ *------------------------------------------------------------------
+ * 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 <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)
+{
+  struct ether_header *resp = (struct ether_header *) eth_resp;
+  memcpy (resp->ether_dhost, eth->ether_shost, 6);
+
+  uint8_t hw_addr[6];
+  int i;
+  for (i = 0; i < 6; i++)
+    {
+      hw_addr[i] = 'a';
+    }
+  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 = 0x5400;
+  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 = ICMP_ECHOREPLY;
+  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])
+{
+  struct ether_header *eh;
+  struct ether_arp *eah;
+  struct iphdr *ip;
+  struct icmphdr *icmp;
+  *out_size = 0;
+
+  eh = (struct ether_header *) in_pck;
+  *out_size = resolve_eth (eh, out_pck);
+
+  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);
+      *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;
+	}
+    }
+  return 0;
+}