IPv6 NS: use the mcast rewrite node to fill in the destination MAC

- move the IPv6 incomplete and glean node to ip6_neighbour.c (so it has access to ip6_neighbour_main_t)
- use the RA info config on the interface to find the multicast adj to use

Change-Id: I835e419072abe54fb09dafb0e7eb0a9e50eba1af
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 275 insertions, 0 deletions

diff --git a/src/vnet/ip/ip6_neighbor.c b/src/vnet/ip/ip6_neighbor.c
index 8e444024c44..34ddd7d2d58 100644
--- a/src/vnet/ip/ip6_neighbor.c
+++ b/src/vnet/ip/ip6_neighbor.c
@@ -3070,6 +3070,281 @@ VLIB_REGISTER_NODE (ip6_icmp_neighbor_advertisement_node,static) =
 };
 /* *INDENT-ON* */
 
+typedef enum
+{
+  IP6_DISCOVER_NEIGHBOR_NEXT_DROP,
+  IP6_DISCOVER_NEIGHBOR_NEXT_REPLY_TX,
+  IP6_DISCOVER_NEIGHBOR_N_NEXT,
+} ip6_discover_neighbor_next_t;
+
+typedef enum
+{
+  IP6_DISCOVER_NEIGHBOR_ERROR_DROP,
+  IP6_DISCOVER_NEIGHBOR_ERROR_REQUEST_SENT,
+  IP6_DISCOVER_NEIGHBOR_ERROR_NO_SOURCE_ADDRESS,
+} 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;
+  ip_lookup_main_t *lm = &im->lookup_main;
+  u32 *from, *to_next_drop;
+  uword n_left_from, n_left_to_next_drop;
+  static f64 time_last_seed_change = -1e100;
+  static u32 hash_seeds[3];
+  static uword hash_bitmap[256 / BITS (uword)];
+  f64 time_now;
+  int bogus_length;
+  ip6_neighbor_main_t *nm = &ip6_neighbor_main;
+
+  if (node->flags & VLIB_NODE_FLAG_TRACE)
+    ip6_forward_next_trace (vm, node, frame, VLIB_TX);
+
+  time_now = vlib_time_now (vm);
+  if (time_now - time_last_seed_change > 1e-3)
+    {
+      uword i;
+      u32 *r = clib_random_buffer_get_data (&vm->random_buffer,
+					    sizeof (hash_seeds));
+      for (i = 0; i < ARRAY_LEN (hash_seeds); i++)
+	hash_seeds[i] = r[i];
+
+      /* Mark all hash keys as been not-seen before. */
+      for (i = 0; i < ARRAY_LEN (hash_bitmap); i++)
+	hash_bitmap[i] = 0;
+
+      time_last_seed_change = time_now;
+    }
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+
+  while (n_left_from > 0)
+    {
+      vlib_get_next_frame (vm, node, IP6_DISCOVER_NEIGHBOR_NEXT_DROP,
+			   to_next_drop, n_left_to_next_drop);
+
+      while (n_left_from > 0 && n_left_to_next_drop > 0)
+	{
+	  vlib_buffer_t *p0;
+	  ip6_header_t *ip0;
+	  u32 pi0, adj_index0, a0, b0, c0, m0, sw_if_index0, drop0;
+	  uword bm0;
+	  ip_adjacency_t *adj0;
+	  vnet_hw_interface_t *hw_if0;
+	  ip6_radv_t *radv_info;
+	  u32 next0;
+
+	  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];
+	    }
+
+	  a0 = hash_seeds[0];
+	  b0 = hash_seeds[1];
+	  c0 = hash_seeds[2];
+
+	  sw_if_index0 = adj0->rewrite_header.sw_if_index;
+	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
+
+	  a0 ^= sw_if_index0;
+	  b0 ^= ip0->dst_address.as_u32[0];
+	  c0 ^= ip0->dst_address.as_u32[1];
+
+	  hash_v3_mix32 (a0, b0, c0);
+
+	  b0 ^= ip0->dst_address.as_u32[2];
+	  c0 ^= ip0->dst_address.as_u32[3];
+
+	  hash_v3_finalize32 (a0, b0, c0);
+
+	  c0 &= BITS (hash_bitmap) - 1;
+	  c0 = c0 / BITS (uword);
+	  m0 = (uword) 1 << (c0 % BITS (uword));
+
+	  bm0 = hash_bitmap[c0];
+	  drop0 = (bm0 & m0) != 0;
+
+	  /* Mark it as seen. */
+	  hash_bitmap[c0] = bm0 | m0;
+
+	  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 (vec_len (nm->if_radv_pool_index_by_sw_if_index) > sw_if_index0)
+	    {
+	      u32 ri = nm->if_radv_pool_index_by_sw_if_index[sw_if_index0];
+
+	      if (ri != ~0)
+		radv_info = pool_elt_at_index (nm->if_radv_pool, ri);
+	      else
+		drop0 = 1;
+	    }
+	  else
+	    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;
+
+	  p0->error =
+	    node->errors[drop0 ? IP6_DISCOVER_NEIGHBOR_ERROR_DROP
+			 : IP6_DISCOVER_NEIGHBOR_ERROR_REQUEST_SENT];
+
+	  if (drop0)
+	    continue;
+
+	  {
+	    u32 bi0 = 0;
+	    icmp6_neighbor_solicitation_header_t *h0;
+	    vlib_buffer_t *b0;
+
+	    h0 = vlib_packet_template_get_packet
+	      (vm, &im->discover_neighbor_packet_template, &bi0);
+
+	    /*
+	     * Build ethernet header.
+	     * Choose source address based on destination lookup
+	     * adjacency.
+	     */
+	    if (!ip6_src_address_for_packet (lm,
+					     sw_if_index0,
+					     &ip0->dst_address,
+					     &h0->ip.src_address))
+	      {
+		/* There is no address on the interface */
+		p0->error =
+		  node->errors[IP6_DISCOVER_NEIGHBOR_ERROR_NO_SOURCE_ADDRESS];
+		vlib_buffer_free (vm, &bi0, 1);
+		continue;
+	      }
+
+	    /*
+	     * Destination address is a solicited node multicast address.
+	     * We need to fill in
+	     * the low 24 bits with low 24 bits of target's address.
+	     */
+	    h0->ip.dst_address.as_u8[13] = ip0->dst_address.as_u8[13];
+	    h0->ip.dst_address.as_u8[14] = ip0->dst_address.as_u8[14];
+	    h0->ip.dst_address.as_u8[15] = ip0->dst_address.as_u8[15];
+
+	    h0->neighbor.target_address = ip0->dst_address;
+
+	    clib_memcpy (h0->link_layer_option.ethernet_address,
+			 hw_if0->hw_address, vec_len (hw_if0->hw_address));
+
+	    /* $$$$ appears we need this; why is the checksum non-zero? */
+	    h0->neighbor.icmp.checksum = 0;
+	    h0->neighbor.icmp.checksum =
+	      ip6_tcp_udp_icmp_compute_checksum (vm, 0, &h0->ip,
+						 &bogus_length);
+
+	    ASSERT (bogus_length == 0);
+
+	    vlib_buffer_copy_trace_flag (vm, p0, bi0);
+	    b0 = vlib_get_buffer (vm, bi0);
+	    vnet_buffer (b0)->sw_if_index[VLIB_TX]
+	      = vnet_buffer (p0)->sw_if_index[VLIB_TX];
+
+	    vnet_buffer (b0)->ip.adj_index[VLIB_TX] =
+	      radv_info->mcast_adj_index;
+
+	    b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
+	    next0 = IP6_DISCOVER_NEIGHBOR_NEXT_REPLY_TX;
+
+	    vlib_set_next_frame_buffer (vm, node, next0, bi0);
+	  }
+	}
+
+      vlib_put_next_frame (vm, node, IP6_DISCOVER_NEIGHBOR_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_DISCOVER_NEIGHBOR_ERROR_DROP] = "address overflow drops",
+  [IP6_DISCOVER_NEIGHBOR_ERROR_REQUEST_SENT] = "neighbor solicitations sent",
+  [IP6_DISCOVER_NEIGHBOR_ERROR_NO_SOURCE_ADDRESS]
+    = "no source address for ND solicitation",
+};
+
+/* *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_DISCOVER_NEIGHBOR_N_NEXT,
+  .next_nodes =
+  {
+    [IP6_DISCOVER_NEIGHBOR_NEXT_DROP] = "ip6-drop",
+    [IP6_DISCOVER_NEIGHBOR_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_DISCOVER_NEIGHBOR_N_NEXT,
+  .next_nodes =
+  {
+    [IP6_DISCOVER_NEIGHBOR_NEXT_DROP] = "ip6-drop",
+    [IP6_DISCOVER_NEIGHBOR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
+  },
+};
+/* *INDENT-ON* */
+
 /* API support functions */
 int
 ip6_neighbor_ra_config (vlib_main_t * vm, u32 sw_if_index,