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, 319 insertions, 0 deletions

diff --git a/src/vnet/ip-neighbor/ip4_neighbor.c b/src/vnet/ip-neighbor/ip4_neighbor.c
new file mode 100644
index 00000000000..2a9e2675a78
--- /dev/null
+++ b/src/vnet/ip-neighbor/ip4_neighbor.c
@@ -0,0 +1,319 @@
+/*
+ * Copyright (c) 2015 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.
+ */
+/*
+ * ip/ip4_forward.c: IP v4 forwarding
+ *
+ * Copyright (c) 2008 Eliot Dresselhaus
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <vnet/ip-neighbor/ip4_neighbor.h>
+#include <vnet/ethernet/ethernet.h>
+
+void
+ip4_neighbor_probe_dst (const ip_adjacency_t * adj, const ip4_address_t * dst)
+{
+  ip_interface_address_t *ia;
+  ip4_address_t *src;
+
+  src = ip4_interface_address_matching_destination
+    (&ip4_main,
+     &adj->sub_type.nbr.next_hop.ip4, adj->rewrite_header.sw_if_index, &ia);
+  if (!src)
+    return;
+
+  ip4_neighbor_probe (vlib_get_main (), vnet_get_main (), adj, src, dst);
+}
+
+void
+ip4_neighbor_advertise (vlib_main_t * vm,
+			vnet_main_t * vnm,
+			u32 sw_if_index, const ip4_address_t * addr)
+{
+  vnet_hw_interface_t *hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
+  ip4_main_t *i4m = &ip4_main;
+  u8 *rewrite, rewrite_len;
+
+  if (NULL == addr)
+    {
+      ip4_main_t *i4m = &ip4_main;
+      addr = ip4_interface_first_address (i4m, sw_if_index, 0);
+    }
+
+  if (addr)
+    {
+      clib_warning ("Sending GARP for IP4 address %U on sw_if_idex %d",
+		    format_ip4_address, addr, sw_if_index);
+
+      /* Form GARP packet for output - Gratuitous ARP is an ARP request packet
+         where the interface IP/MAC pair is used for both source and request
+         MAC/IP pairs in the request */
+      u32 bi = 0;
+      ethernet_arp_header_t *h = vlib_packet_template_get_packet
+	(vm, &i4m->ip4_arp_request_packet_template, &bi);
+
+      if (!h)
+	return;
+
+      mac_address_from_bytes (&h->ip4_over_ethernet[0].mac, hi->hw_address);
+      mac_address_from_bytes (&h->ip4_over_ethernet[1].mac, hi->hw_address);
+      h->ip4_over_ethernet[0].ip4 = addr[0];
+      h->ip4_over_ethernet[1].ip4 = addr[0];
+
+      /* Setup MAC header with ARP Etype and broadcast DMAC */
+      vlib_buffer_t *b = vlib_get_buffer (vm, bi);
+      rewrite =
+	ethernet_build_rewrite (vnm, sw_if_index, VNET_LINK_ARP,
+				VNET_REWRITE_FOR_SW_INTERFACE_ADDRESS_BROADCAST);
+      rewrite_len = vec_len (rewrite);
+      vlib_buffer_advance (b, -rewrite_len);
+      ethernet_header_t *e = vlib_buffer_get_current (b);
+      clib_memcpy_fast (e->dst_address, rewrite, rewrite_len);
+      vec_free (rewrite);
+
+      /* Send GARP 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);
+    }
+}
+
+always_inline uword
+ip4_arp_inline (vlib_main_t * vm,
+		vlib_node_runtime_t * node,
+		vlib_frame_t * frame, int is_glean)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  ip4_main_t *im = &ip4_main;
+  ip_lookup_main_t *lm = &im->lookup_main;
+  u32 *from, *to_next_drop;
+  uword n_left_from, n_left_to_next_drop, next_index;
+  u32 thread_index = vm->thread_index;
+  u64 seed;
+
+  if (node->flags & VLIB_NODE_FLAG_TRACE)
+    ip4_forward_next_trace (vm, node, frame, VLIB_TX);
+
+  seed = throttle_seed (&im->arp_throttle, thread_index, vlib_time_now (vm));
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+  if (next_index == IP4_ARP_NEXT_DROP)
+    next_index = IP4_ARP_N_NEXT;	/* point to first interface */
+
+  while (n_left_from > 0)
+    {
+      vlib_get_next_frame (vm, node, IP4_ARP_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;
+	  ip4_address_t resolve0, src0;
+	  vlib_buffer_t *p0, *b0;
+	  ip_adjacency_t *adj0;
+	  u64 r0;
+
+	  pi0 = from[0];
+	  p0 = vlib_get_buffer (vm, pi0);
+
+	  from += 1;
+	  n_left_from -= 1;
+	  to_next_drop[0] = pi0;
+	  to_next_drop += 1;
+	  n_left_to_next_drop -= 1;
+
+	  adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
+	  adj0 = adj_get (adj_index0);
+	  sw_if_index0 = adj0->rewrite_header.sw_if_index;
+
+	  if (is_glean)
+	    {
+	      /* resolve the packet's destination */
+	      ip4_header_t *ip0 = vlib_buffer_get_current (p0);
+	      resolve0 = ip0->dst_address;
+	      src0 = adj0->sub_type.glean.receive_addr.ip4;
+	    }
+	  else
+	    {
+	      /* resolve the incomplete adj */
+	      resolve0 = adj0->sub_type.nbr.next_hop.ip4;
+	      /* Src IP address in ARP header. */
+	      if (ip4_src_address_for_packet (lm, sw_if_index0, &src0))
+		{
+		  /* No source address available */
+		  p0->error = node->errors[IP4_ARP_ERROR_NO_SOURCE_ADDRESS];
+		  continue;
+		}
+	    }
+
+	  /* combine the address and interface for the hash key */
+	  r0 = (u64) resolve0.data_u32 << 32;
+	  r0 |= sw_if_index0;
+
+	  if (throttle_check (&im->arp_throttle, thread_index, r0, seed))
+	    {
+	      p0->error = node->errors[IP4_ARP_ERROR_THROTTLED];
+	      continue;
+	    }
+
+	  /*
+	   * 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)
+	    {
+	      p0->error = node->errors[IP4_ARP_ERROR_RESOLVED];
+	      continue;
+	    }
+
+	  /*
+	   * Can happen if the control-plane is programming tables
+	   * with traffic flowing; at least that's today's lame excuse.
+	   */
+	  if ((is_glean && adj0->lookup_next_index != IP_LOOKUP_NEXT_GLEAN)
+	      || (!is_glean && adj0->lookup_next_index != IP_LOOKUP_NEXT_ARP))
+	    {
+	      p0->error = node->errors[IP4_ARP_ERROR_NON_ARP_ADJ];
+	      continue;
+	    }
+
+	  /* Send ARP request. */
+	  b0 = ip4_neighbor_probe (vm, vnm, adj0, &src0, &resolve0);
+
+	  if (PREDICT_TRUE (NULL != b0))
+	    {
+	      /* copy the persistent fields from the original */
+	      clib_memcpy_fast (b0->opaque2, p0->opaque2,
+				sizeof (p0->opaque2));
+	      p0->error = node->errors[IP4_ARP_ERROR_REQUEST_SENT];
+	    }
+	  else
+	    {
+	      p0->error = node->errors[IP4_ARP_ERROR_NO_BUFFERS];
+	      continue;
+	    }
+	}
+
+      vlib_put_next_frame (vm, node, IP4_ARP_NEXT_DROP, n_left_to_next_drop);
+    }
+
+  return frame->n_vectors;
+}
+
+VLIB_NODE_FN (ip4_arp_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
+			     vlib_frame_t * frame)
+{
+  return (ip4_arp_inline (vm, node, frame, 0));
+}
+
+VLIB_NODE_FN (ip4_glean_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
+			       vlib_frame_t * frame)
+{
+  return (ip4_arp_inline (vm, node, frame, 1));
+}
+
+static char *ip4_arp_error_strings[] = {
+  [IP4_ARP_ERROR_THROTTLED] = "ARP requests throttled",
+  [IP4_ARP_ERROR_RESOLVED] = "ARP requests resolved",
+  [IP4_ARP_ERROR_NO_BUFFERS] = "ARP requests out of buffer",
+  [IP4_ARP_ERROR_REQUEST_SENT] = "ARP requests sent",
+  [IP4_ARP_ERROR_NON_ARP_ADJ] = "ARPs to non-ARP adjacencies",
+  [IP4_ARP_ERROR_NO_SOURCE_ADDRESS] = "no source address for ARP request",
+};
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (ip4_arp_node) =
+{
+  .name = "ip4-arp",
+  .vector_size = sizeof (u32),
+  .format_trace = format_ip4_forward_next_trace,
+  .n_errors = ARRAY_LEN (ip4_arp_error_strings),
+  .error_strings = ip4_arp_error_strings,
+  .n_next_nodes = IP4_ARP_N_NEXT,
+  .next_nodes = {
+    [IP4_ARP_NEXT_DROP] = "ip4-drop",
+  },
+};
+
+VLIB_REGISTER_NODE (ip4_glean_node) =
+{
+  .name = "ip4-glean",
+  .vector_size = sizeof (u32),
+  .format_trace = format_ip4_forward_next_trace,
+  .n_errors = ARRAY_LEN (ip4_arp_error_strings),
+  .error_strings = ip4_arp_error_strings,
+  .n_next_nodes = IP4_ARP_N_NEXT,
+  .next_nodes = {
+    [IP4_ARP_NEXT_DROP] = "ip4-drop",
+  },
+};
+/* *INDENT-ON* */
+
+#define foreach_notrace_ip4_arp_error           \
+_(THROTTLED)                                    \
+_(RESOLVED)                                     \
+_(NO_BUFFERS)                                   \
+_(REQUEST_SENT)                                 \
+_(NON_ARP_ADJ)                                  \
+_(NO_SOURCE_ADDRESS)
+
+static clib_error_t *
+arp_notrace_init (vlib_main_t * vm)
+{
+  vlib_node_runtime_t *rt = vlib_node_get_runtime (vm, ip4_arp_node.index);
+
+  /* don't trace ARP request packets */
+#define _(a)                                    \
+    vnet_pcap_drop_trace_filter_add_del         \
+        (rt->errors[IP4_ARP_ERROR_##a],         \
+         1 /* is_add */);
+  foreach_notrace_ip4_arp_error;
+#undef _
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (arp_notrace_init);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */