[router] IPv6 support and refactoring.

This change adds support for IPv6 while refactoring most of the
original plugin code in the following ways.

 - Adhere to vpp style guidelines.

 - Split the netlink, node, and tap processing into separate
   files named with a "tap_inject" prefix which more accurately
   represents the functionality.

 - Implement our own tap management and rx/tx. This is to reduce
   the overhead of passing packets in and out of vnet tap
   devices, in favor of directly reading/writing from the tap.

 - Change how nodes work. Now we have neighbor, rx, and tx nodes.
   The neighbor node sends ARP replies and ICMP6 neighbor
   advertisements to the arp-input and icmp6-neighbor-solicitation
   nodes, respectively, before also injecting the packet to the
   host, making it possible for both vpp and the host network stack
   to resolve the next hop. The tx node injects packets into the
   host by writing to the tap. The rx node reads packets from the
   tap and sends them on its associated data plane interface.

 - Simplify the CLI. Instead of creating taps specifically for
   a given interface we create a tap for all of the Ethernet
   interfaces with the "enable tap-inject" CLI command. The
   interfaces are named with a "vpp" prefix, i.e. "vpp0". Also
   add a "disable tap-inject" option.

 - Provide ability to enable at configuration time with the
   tap-inject { enable } stanza.

Change-Id: I6b56da606e2da1d793ce6aca222fe4eb5a4e070d
Signed-off-by: Jeff Shaw <jeffrey.b.shaw@intel.com>

1 files changed, 170 insertions, 0 deletions

diff --git a/router/router/tap_inject_tap.c b/router/router/tap_inject_tap.c
new file mode 100644
index 0000000..9650323
--- /dev/null
+++ b/router/router/tap_inject_tap.c
@@ -0,0 +1,170 @@
+/*
+ * Copyright 2016 Intel Corporation
+ *
+ * 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 "tap_inject.h"
+
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <linux/if.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/if_tun.h>
+#include <netinet/in.h>
+#include <vnet/unix/tuntap.h>
+
+#include <vlib/unix/unix.h>
+
+
+static clib_error_t *
+tap_inject_tap_read (unix_file_t * f)
+{
+  vlib_main_t * vm = vlib_get_main ();
+  tap_inject_main_t * im = tap_inject_get_main ();
+
+  vec_add1 (im->rx_file_descriptors, f->file_descriptor);
+
+  vlib_node_set_interrupt_pending (vm, im->rx_node_index);
+
+  return 0;
+}
+
+#define TAP_INJECT_TAP_BASE_NAME "vpp"
+
+clib_error_t *
+tap_inject_tap_connect (vnet_hw_interface_t * hw)
+{
+  vnet_main_t * vnet_main = vnet_get_main ();
+  vnet_sw_interface_t * sw = vnet_get_sw_interface (vnet_main, hw->hw_if_index);
+  static const int one = 1;
+  int fd;
+  struct ifreq ifr;
+  unix_file_t template;
+  u32 tap_fd;
+  u8 * name;
+
+  memset (&ifr, 0, sizeof (ifr));
+  memset (&template, 0, sizeof (template));
+
+  ASSERT (hw->hw_if_index == sw->sw_if_index);
+
+  /* Create the tap. */
+  tap_fd = open ("/dev/net/tun", O_RDWR);
+
+  if ((int)tap_fd < 0)
+    return clib_error_return (0, "failed to open tun device");
+
+  name = format (0, TAP_INJECT_TAP_BASE_NAME "%u%c", hw->hw_instance, 0);
+
+  strncpy (ifr.ifr_name, (char *) name, sizeof (ifr.ifr_name) - 1);
+  ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+
+  if (ioctl (tap_fd, TUNSETIFF, (void *)&ifr) < 0)
+    {
+      close (tap_fd);
+      return clib_error_return (0, "failed to create tap");
+    }
+
+  if (ioctl (tap_fd, FIONBIO, &one) < 0)
+    {
+      close (tap_fd);
+      return clib_error_return (0, "failed to set tap to non-blocking io");
+    }
+
+  /* Open a socket to configure the device. */
+  fd = socket (PF_PACKET, SOCK_RAW, htons (ETH_P_ALL));
+
+  if (fd < 0)
+    {
+      close (tap_fd);
+      return clib_error_return (0, "failed to configure tap");
+    }
+
+  if (hw->hw_address)
+    clib_memcpy (ifr.ifr_hwaddr.sa_data, hw->hw_address, ETHER_ADDR_LEN);
+
+  ifr.ifr_hwaddr.sa_family = ARPHRD_ETHER;
+
+  /* Set the hardware address. */
+  if (ioctl (fd, SIOCSIFHWADDR, &ifr) < 0)
+    {
+      close (tap_fd);
+      close (fd);
+      return clib_error_return (0, "failed to set tap hardware address");
+    }
+
+  /* Get the tap if index. */
+  if (ioctl (fd, SIOCGIFINDEX, &ifr) < 0)
+    {
+      close (tap_fd);
+      close (fd);
+      return clib_error_return (0, "failed to procure tap if index");
+    }
+
+  close (fd);
+
+  /* Get notified when the tap needs to be read. */
+  template.read_function = tap_inject_tap_read;
+  template.file_descriptor = tap_fd;
+
+  unix_file_add (&unix_main, &template);
+
+  tap_inject_insert_tap (sw->sw_if_index, tap_fd, ifr.ifr_ifindex);
+
+  return 0;
+}
+
+clib_error_t *
+tap_inject_tap_disconnect (u32 sw_if_index)
+{
+  u32 tap_fd;
+
+  tap_fd = tap_inject_lookup_tap_fd (sw_if_index);
+  if (tap_fd == ~0)
+    return clib_error_return (0, "failed to disconnect tap");
+
+  tap_inject_delete_tap (sw_if_index);
+
+  close (tap_fd);
+  return 0;
+}
+
+
+u8 *
+format_tap_inject_tap_name (u8 * s, va_list * args)
+{
+  int fd;
+  struct ifreq ifr;
+
+  fd = socket (PF_PACKET, SOCK_RAW, htons (ETH_P_ALL));
+
+  if (fd < 0)
+    return 0;
+
+  memset (&ifr, 0, sizeof (ifr));
+
+  ifr.ifr_ifindex = va_arg (*args, u32);
+
+  if (ioctl (fd, SIOCGIFNAME, &ifr) < 0)
+    {
+      close (fd);
+      return 0;
+    }
+
+  close (fd);
+
+  return format (s, "%s", ifr.ifr_name);
+}