ip: Protocol Independent IP Neighbors

Type: feature

 - ip-neighbour: generic neighbour handling; APIs, DBs, event handling,
aging
 - arp: ARP protocol implementation
 - ip6-nd; IPv6 neighbor discovery implementation; separate ND,
MLD, RA
 - ip6-link; manage link-local addresses
 - l2-arp-term; events separated from IP neighbours, since they are not
the same.

vnet retains just enough education to perform ND/ARP packet
construction.
arp and ip6-nd to be moved to plugins soon.

Change-Id: I88dedd0006b299344f4c7024a0aa5baa6b9a8bbe
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 338 insertions, 0 deletions

diff --git a/src/vnet/ip-neighbor/ip6_neighbor.c b/src/vnet/ip-neighbor/ip6_neighbor.c
new file mode 100644
index 00000000000..325db8c6277
--- /dev/null
+++ b/src/vnet/ip-neighbor/ip6_neighbor.c
@@ -0,0 +1,338 @@
+/*
+ * ip/ip6_neighbor.c: IP6 neighbor handling
+ *
+ * Copyright (c) 2010 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 <vnet/ip-neighbor/ip6_neighbor.h>
+
+void
+ip6_neighbor_probe_dst (const ip_adjacency_t * adj, const ip6_address_t * dst)
+{
+  ip_interface_address_t *ia;
+  ip6_address_t *src;
+
+  src = ip6_interface_address_matching_destination
+    (&ip6_main, dst, adj->rewrite_header.sw_if_index, &ia);
+
+  if (!src)
+    return;
+
+  ip6_neighbor_probe (vlib_get_main (), vnet_get_main (), adj, src, dst);
+}
+
+void
+ip6_neighbor_advertise (vlib_main_t * vm,
+			vnet_main_t * vnm,
+			u32 sw_if_index, const ip6_address_t * addr)
+{
+  vnet_hw_interface_t *hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
+  ip6_main_t *i6m = &ip6_main;
+  u8 *rewrite, rewrite_len;
+  u8 dst_address[6];
+
+  if (NULL == addr)
+    addr = ip6_interface_first_address (i6m, sw_if_index);
+
+  if (addr)
+    {
+      clib_warning
+	("Sending unsolicitated NA IP6 address %U on sw_if_idex %d",
+	 format_ip6_address, addr, sw_if_index);
+
+      /* Form unsolicited neighbor advertisement packet from NS pkt template */
+      int bogus_length;
+      u32 bi = 0;
+      icmp6_neighbor_solicitation_header_t *h =
+	vlib_packet_template_get_packet (vm,
+					 &ip6_neighbor_packet_template,
+					 &bi);
+      if (!h)
+	return;
+
+      ip6_set_reserved_multicast_address (&h->ip.dst_address,
+					  IP6_MULTICAST_SCOPE_link_local,
+					  IP6_MULTICAST_GROUP_ID_all_hosts);
+      h->ip.src_address = addr[0];
+      h->neighbor.icmp.type = ICMP6_neighbor_advertisement;
+      h->neighbor.target_address = addr[0];
+      h->neighbor.advertisement_flags = clib_host_to_net_u32
+	(ICMP6_NEIGHBOR_ADVERTISEMENT_FLAG_OVERRIDE);
+      h->link_layer_option.header.type =
+	ICMP6_NEIGHBOR_DISCOVERY_OPTION_target_link_layer_address;
+      clib_memcpy (h->link_layer_option.ethernet_address,
+		   hi->hw_address, vec_len (hi->hw_address));
+      h->neighbor.icmp.checksum =
+	ip6_tcp_udp_icmp_compute_checksum (vm, 0, &h->ip, &bogus_length);
+      ASSERT (bogus_length == 0);
+
+      /* Setup MAC header with IP6 Etype and mcast DMAC */
+      vlib_buffer_t *b = vlib_get_buffer (vm, bi);
+      ip6_multicast_ethernet_address (dst_address,
+				      IP6_MULTICAST_GROUP_ID_all_hosts);
+      rewrite =
+	ethernet_build_rewrite (vnm, sw_if_index, VNET_LINK_IP6, dst_address);
+      rewrite_len = vec_len (rewrite);
+      vlib_buffer_advance (b, -rewrite_len);
+      ethernet_header_t *e = vlib_buffer_get_current (b);
+      clib_memcpy (e->dst_address, rewrite, rewrite_len);
+      vec_free (rewrite);
+
+      /* Send unsolicited ND advertisement packet out the specified interface */
+      vnet_buffer (b)->sw_if_index[VLIB_RX] =
+	vnet_buffer (b)->sw_if_index[VLIB_TX] = sw_if_index;
+      vlib_frame_t *f = vlib_get_frame_to_node (vm, hi->output_node_index);
+      u32 *to_next = vlib_frame_vector_args (f);
+      to_next[0] = bi;
+      f->n_vectors = 1;
+      vlib_put_frame_to_node (vm, hi->output_node_index, f);
+    }
+}
+
+typedef enum
+{
+  IP6_NBR_NEXT_DROP,
+  IP6_NBR_NEXT_REPLY_TX,
+  IP6_NBR_N_NEXT,
+} ip6_discover_neighbor_next_t;
+
+typedef enum
+{
+  IP6_NBR_ERROR_DROP,
+  IP6_NBR_ERROR_REQUEST_SENT,
+  IP6_NBR_ERROR_NO_SOURCE_ADDRESS,
+  IP6_NBR_ERROR_NO_BUFFERS,
+} ip6_discover_neighbor_error_t;
+
+static uword
+ip6_discover_neighbor_inline (vlib_main_t * vm,
+			      vlib_node_runtime_t * node,
+			      vlib_frame_t * frame, int is_glean)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  ip6_main_t *im = &ip6_main;
+  u32 *from, *to_next_drop;
+  uword n_left_from, n_left_to_next_drop;
+  u64 seed;
+  u32 thread_index = vm->thread_index;
+
+  if (node->flags & VLIB_NODE_FLAG_TRACE)
+    ip6_forward_next_trace (vm, node, frame, VLIB_TX);
+
+  seed = throttle_seed (&im->nd_throttle, thread_index, vlib_time_now (vm));
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+
+  while (n_left_from > 0)
+    {
+      vlib_get_next_frame (vm, node, IP6_NBR_NEXT_DROP,
+			   to_next_drop, n_left_to_next_drop);
+
+      while (n_left_from > 0 && n_left_to_next_drop > 0)
+	{
+	  u32 pi0, adj_index0, sw_if_index0, drop0, r0;
+	  vnet_hw_interface_t *hw_if0;
+	  vlib_buffer_t *p0, *b0;
+	  ip_adjacency_t *adj0;
+	  ip6_address_t src;
+	  ip6_header_t *ip0;
+
+	  pi0 = from[0];
+
+	  p0 = vlib_get_buffer (vm, pi0);
+
+	  adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
+
+	  ip0 = vlib_buffer_get_current (p0);
+
+	  adj0 = adj_get (adj_index0);
+
+	  if (!is_glean)
+	    {
+	      ip0->dst_address.as_u64[0] =
+		adj0->sub_type.nbr.next_hop.ip6.as_u64[0];
+	      ip0->dst_address.as_u64[1] =
+		adj0->sub_type.nbr.next_hop.ip6.as_u64[1];
+	    }
+
+	  sw_if_index0 = adj0->rewrite_header.sw_if_index;
+	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
+
+	  /* combine the address and interface for a hash */
+	  r0 = ip6_address_hash_to_u64 (&ip0->dst_address) ^ sw_if_index0;
+
+	  drop0 = throttle_check (&im->nd_throttle, thread_index, r0, seed);
+
+	  from += 1;
+	  n_left_from -= 1;
+	  to_next_drop[0] = pi0;
+	  to_next_drop += 1;
+	  n_left_to_next_drop -= 1;
+
+	  hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);
+
+	  /* If the interface is link-down, drop the pkt */
+	  if (!(hw_if0->flags & VNET_HW_INTERFACE_FLAG_LINK_UP))
+	    drop0 = 1;
+
+	  if (!ip6_link_is_enabled (sw_if_index0))
+	    drop0 = 1;
+
+	  /*
+	   * the adj has been updated to a rewrite but the node the DPO that got
+	   * us here hasn't - yet. no big deal. we'll drop while we wait.
+	   */
+	  if (IP_LOOKUP_NEXT_REWRITE == adj0->lookup_next_index)
+	    drop0 = 1;
+
+	  if (drop0)
+	    {
+	      p0->error = node->errors[IP6_NBR_ERROR_DROP];
+	      continue;
+	    }
+
+	  /*
+	   * Choose source address based on destination lookup
+	   * adjacency.
+	   */
+	  if (!ip6_src_address_for_packet (sw_if_index0,
+					   &ip0->dst_address, &src))
+	    {
+	      /* There is no address on the interface */
+	      p0->error = node->errors[IP6_NBR_ERROR_NO_SOURCE_ADDRESS];
+	      continue;
+	    }
+
+	  b0 = ip6_neighbor_probe (vm, vnm, adj0, &src, &ip0->dst_address);
+
+	  if (PREDICT_TRUE (NULL != b0))
+	    {
+	      clib_memcpy_fast (b0->opaque2, p0->opaque2,
+				sizeof (p0->opaque2));
+	      b0->flags |= p0->flags & VLIB_BUFFER_IS_TRACED;
+	      b0->trace_handle = p0->trace_handle;
+	      p0->error = node->errors[IP6_NBR_ERROR_REQUEST_SENT];
+	    }
+	  else
+	    {
+	      /* There is no address on the interface */
+	      p0->error = node->errors[IP6_NBR_ERROR_NO_BUFFERS];
+	      continue;
+	    }
+	}
+
+      vlib_put_next_frame (vm, node, IP6_NBR_NEXT_DROP, n_left_to_next_drop);
+    }
+
+  return frame->n_vectors;
+}
+
+static uword
+ip6_discover_neighbor (vlib_main_t * vm,
+		       vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return (ip6_discover_neighbor_inline (vm, node, frame, 0));
+}
+
+static uword
+ip6_glean (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return (ip6_discover_neighbor_inline (vm, node, frame, 1));
+}
+
+static char *ip6_discover_neighbor_error_strings[] = {
+  [IP6_NBR_ERROR_DROP] = "address overflow drops",
+  [IP6_NBR_ERROR_REQUEST_SENT] = "neighbor solicitations sent",
+  [IP6_NBR_ERROR_NO_SOURCE_ADDRESS] = "no source address for ND solicitation",
+  [IP6_NBR_ERROR_NO_BUFFERS] = "no buffers",
+};
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (ip6_glean_node) =
+{
+  .function = ip6_glean,
+  .name = "ip6-glean",
+  .vector_size = sizeof (u32),
+  .format_trace = format_ip6_forward_next_trace,
+  .n_errors = ARRAY_LEN (ip6_discover_neighbor_error_strings),
+  .error_strings = ip6_discover_neighbor_error_strings,
+  .n_next_nodes = IP6_NBR_N_NEXT,
+  .next_nodes =
+  {
+    [IP6_NBR_NEXT_DROP] = "ip6-drop",
+    [IP6_NBR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
+  },
+};
+VLIB_REGISTER_NODE (ip6_discover_neighbor_node) =
+{
+  .function = ip6_discover_neighbor,
+  .name = "ip6-discover-neighbor",
+  .vector_size = sizeof (u32),
+  .format_trace = format_ip6_forward_next_trace,
+  .n_errors = ARRAY_LEN (ip6_discover_neighbor_error_strings),
+  .error_strings = ip6_discover_neighbor_error_strings,
+  .n_next_nodes = IP6_NBR_N_NEXT,
+  .next_nodes =
+  {
+    [IP6_NBR_NEXT_DROP] = "ip6-drop",
+    [IP6_NBR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
+  },
+};
+/* *INDENT-ON* */
+
+/* Template used to generate IP6 neighbor solicitation packets. */
+vlib_packet_template_t ip6_neighbor_packet_template;
+
+static clib_error_t *
+ip6_neighbor_init (vlib_main_t * vm)
+{
+  icmp6_neighbor_solicitation_header_t p;
+
+  clib_memset (&p, 0, sizeof (p));
+
+  p.ip.ip_version_traffic_class_and_flow_label =
+    clib_host_to_net_u32 (0x6 << 28);
+  p.ip.payload_length =
+    clib_host_to_net_u16 (sizeof (p) -
+			  STRUCT_OFFSET_OF
+			  (icmp6_neighbor_solicitation_header_t, neighbor));
+  p.ip.protocol = IP_PROTOCOL_ICMP6;
+  p.ip.hop_limit = 255;
+  ip6_set_solicited_node_multicast_address (&p.ip.dst_address, 0);
+
+  p.neighbor.icmp.type = ICMP6_neighbor_solicitation;
+
+  p.link_layer_option.header.type =
+    ICMP6_NEIGHBOR_DISCOVERY_OPTION_source_link_layer_address;
+  p.link_layer_option.header.n_data_u64s =
+    sizeof (p.link_layer_option) / sizeof (u64);
+
+  vlib_packet_template_init (vm,
+			     &ip6_neighbor_packet_template, &p, sizeof (p),
+			     /* alloc chunk size */ 8,
+			     "ip6 neighbor discovery");
+
+  return NULL;
+}
+
+VLIB_INIT_FUNCTION (ip6_neighbor_init);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */