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, 481 insertions, 0 deletions

diff --git a/src/vnet/l2/l2_arp_term.c b/src/vnet/l2/l2_arp_term.c
new file mode 100644
index 00000000000..982fd9f05ea
--- /dev/null
+++ b/src/vnet/l2/l2_arp_term.c
@@ -0,0 +1,481 @@
+/*
+ * l2/l2_arp_term.c: IP v4 ARP L2 BD termination
+ *
+ * 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 <vlibmemory/api.h>
+
+#include <vnet/l2/l2_arp_term.h>
+#include <vnet/l2/l2_input.h>
+#include <vnet/l2/feat_bitmap.h>
+
+#include <vnet/ip/ip4_packet.h>
+#include <vnet/ethernet/arp_packet.h>
+
+static const u8 vrrp_prefix[] = { 0x00, 0x00, 0x5E, 0x00, 0x01 };
+
+l2_arp_term_main_t l2_arp_term_main;
+
+/*
+ * ARP/ND Termination in a L2 Bridge Domain based on IP4/IP6 to MAC
+ * hash tables mac_by_ip4 and mac_by_ip6 for each BD.
+ */
+typedef enum
+{
+  ARP_TERM_NEXT_L2_OUTPUT,
+  ARP_TERM_NEXT_DROP,
+  ARP_TERM_N_NEXT,
+} arp_term_next_t;
+
+u32 arp_term_next_node_index[32];
+
+typedef struct
+{
+  u8 packet_data[64];
+} ethernet_arp_input_trace_t;
+
+#define foreach_ethernet_arp_error					\
+  _ (replies_sent, "ARP replies sent")					\
+  _ (l2_type_not_ethernet, "L2 type not ethernet")			\
+  _ (l3_type_not_ip4, "L3 type not IP4")				\
+  _ (l3_src_address_not_local, "IP4 source address not local to subnet") \
+  _ (l3_dst_address_not_local, "IP4 destination address not local to subnet") \
+  _ (l3_dst_address_unset, "IP4 destination address is unset")          \
+  _ (l3_src_address_is_local, "IP4 source address matches local interface") \
+  _ (l3_src_address_learned, "ARP request IP4 source address learned")  \
+  _ (replies_received, "ARP replies received")				\
+  _ (opcode_not_request, "ARP opcode not request")                      \
+  _ (proxy_arp_replies_sent, "Proxy ARP replies sent")			\
+  _ (l2_address_mismatch, "ARP hw addr does not match L2 frame src addr") \
+  _ (gratuitous_arp, "ARP probe or announcement dropped") \
+  _ (interface_no_table, "Interface is not mapped to an IP table") \
+  _ (interface_not_ip_enabled, "Interface is not IP enabled") \
+  _ (unnumbered_mismatch, "RX interface is unnumbered to different subnet") \
+
+typedef enum
+{
+#define _(sym,string) ETHERNET_ARP_ERROR_##sym,
+  foreach_ethernet_arp_error
+#undef _
+    ETHERNET_ARP_N_ERROR,
+} ethernet_arp_reply_error_t;
+
+static char *ethernet_arp_error_strings[] = {
+#define _(sym,string) string,
+  foreach_ethernet_arp_error
+#undef _
+};
+
+static u8 *
+format_arp_term_input_trace (u8 * s, va_list * va)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*va, vlib_node_t *);
+  ethernet_arp_input_trace_t *t = va_arg (*va, ethernet_arp_input_trace_t *);
+
+  /* arp-term trace data saved is either arp or ip6/icmp6 packet:
+     - for arp, the 1st 16-bit field is hw type of value of 0x0001.
+     - for ip6, the first nibble has value of 6. */
+  s = format (s, "%U", t->packet_data[0] == 0 ?
+	      format_ethernet_arp_header : format_ip6_header,
+	      t->packet_data, sizeof (t->packet_data));
+
+  return s;
+}
+
+void
+l2_arp_term_set_publisher_node (bool on)
+{
+  l2_arp_term_main_t *l2am = &l2_arp_term_main;
+
+  l2am->publish = on;
+}
+
+static int
+l2_arp_term_publish (l2_arp_term_publish_event_t * ctx)
+{
+  l2_arp_term_main_t *l2am = &l2_arp_term_main;
+
+  vec_add1 (l2am->publish_events, *ctx);
+
+  vlib_process_signal_event (vlib_get_main (),
+			     l2_arp_term_process_node.index,
+			     L2_ARP_TERM_EVENT_PUBLISH, 0);
+
+  return 0;
+}
+
+static inline void
+l2_arp_term_publish_v4_dp (u32 sw_if_index,
+			   const ethernet_arp_ip4_over_ethernet_address_t * a)
+{
+  l2_arp_term_main_t *l2am = &l2_arp_term_main;
+
+  if (!l2am->publish)
+    return;
+
+  l2_arp_term_publish_event_t args = {
+    .sw_if_index = sw_if_index,
+    .type = IP46_TYPE_IP4,
+    .ip.ip4 = a->ip4,
+    .mac = a->mac,
+  };
+
+  vl_api_rpc_call_main_thread (l2_arp_term_publish, (u8 *) & args,
+			       sizeof (args));
+}
+
+static inline void
+l2_arp_term_publish_v6_dp (u32 sw_if_index,
+			   const ip6_address_t * addr,
+			   const mac_address_t * mac)
+{
+  l2_arp_term_main_t *l2am = &l2_arp_term_main;
+
+  if (!l2am->publish)
+    return;
+
+  l2_arp_term_publish_event_t args = {
+    .sw_if_index = sw_if_index,
+    .type = IP46_TYPE_IP6,
+    .ip.ip6 = *addr,
+    .mac = *mac,
+  };
+
+  vl_api_rpc_call_main_thread (l2_arp_term_publish, (u8 *) & args,
+			       sizeof (args));
+}
+
+static inline int
+vnet_ip6_nd_term (vlib_main_t * vm,
+		  vlib_node_runtime_t * node,
+		  vlib_buffer_t * p0,
+		  ethernet_header_t * eth,
+		  ip6_header_t * ip, u32 sw_if_index, u16 bd_index)
+{
+  icmp6_neighbor_solicitation_or_advertisement_header_t *ndh;
+  mac_address_t mac;
+
+  mac_address_from_bytes (&mac, eth->src_address);
+  ndh = ip6_next_header (ip);
+  if (ndh->icmp.type != ICMP6_neighbor_solicitation &&
+      ndh->icmp.type != ICMP6_neighbor_advertisement)
+    return 0;
+
+  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
+		     (p0->flags & VLIB_BUFFER_IS_TRACED)))
+    {
+      u8 *t0 = vlib_add_trace (vm, node, p0,
+			       sizeof (icmp6_input_trace_t));
+      clib_memcpy (t0, ip, sizeof (icmp6_input_trace_t));
+    }
+
+  /* Check if anyone want ND events for L2 BDs */
+  if (PREDICT_FALSE (!ip6_address_is_link_local_unicast (&ip->src_address)))
+    {
+      l2_arp_term_publish_v6_dp (sw_if_index, &ip->src_address, &mac);
+    }
+
+  /* Check if MAC entry exsist for solicited target IP */
+  if (ndh->icmp.type == ICMP6_neighbor_solicitation)
+    {
+      icmp6_neighbor_discovery_ethernet_link_layer_address_option_t *opt;
+      l2_bridge_domain_t *bd_config;
+      u8 *macp;
+
+      opt = (void *) (ndh + 1);
+      if ((opt->header.type !=
+	   ICMP6_NEIGHBOR_DISCOVERY_OPTION_source_link_layer_address) ||
+	  (opt->header.n_data_u64s != 1))
+	return 0;		/* source link layer address option not present */
+
+      bd_config = vec_elt_at_index (l2input_main.bd_configs, bd_index);
+      macp =
+	(u8 *) hash_get_mem (bd_config->mac_by_ip6, &ndh->target_address);
+      if (macp)
+	{			/* found ip-mac entry, generate eighbor advertisement response */
+	  int bogus_length;
+	  vlib_node_runtime_t *error_node =
+	    vlib_node_get_runtime (vm, ip6_icmp_input_node.index);
+	  ip->dst_address = ip->src_address;
+	  ip->src_address = ndh->target_address;
+	  ip->hop_limit = 255;
+	  opt->header.type =
+	    ICMP6_NEIGHBOR_DISCOVERY_OPTION_target_link_layer_address;
+	  clib_memcpy (opt->ethernet_address, macp, 6);
+	  ndh->icmp.type = ICMP6_neighbor_advertisement;
+	  ndh->advertisement_flags = clib_host_to_net_u32
+	    (ICMP6_NEIGHBOR_ADVERTISEMENT_FLAG_SOLICITED |
+	     ICMP6_NEIGHBOR_ADVERTISEMENT_FLAG_OVERRIDE);
+	  ndh->icmp.checksum = 0;
+	  ndh->icmp.checksum =
+	    ip6_tcp_udp_icmp_compute_checksum (vm, p0, ip, &bogus_length);
+	  clib_memcpy (eth->dst_address, eth->src_address, 6);
+	  clib_memcpy (eth->src_address, macp, 6);
+	  vlib_error_count (vm, error_node->node_index,
+			    ICMP6_ERROR_NEIGHBOR_ADVERTISEMENTS_TX, 1);
+	  return 1;
+	}
+    }
+
+  return 0;
+
+}
+
+static uword
+arp_term_l2bd (vlib_main_t * vm,
+	       vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  l2input_main_t *l2im = &l2input_main;
+  u32 n_left_from, next_index, *from, *to_next;
+  u32 n_replies_sent = 0;
+  u16 last_bd_index = ~0;
+  l2_bridge_domain_t *last_bd_config = 0;
+  l2_input_config_t *cfg0;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  vlib_buffer_t *p0;
+	  ethernet_header_t *eth0;
+	  ethernet_arp_header_t *arp0;
+	  ip6_header_t *iph0;
+	  u8 *l3h0;
+	  u32 pi0, error0, next0, sw_if_index0;
+	  u16 ethertype0;
+	  u16 bd_index0;
+	  u32 ip0;
+	  u8 *macp0;
+
+	  pi0 = from[0];
+	  to_next[0] = pi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  p0 = vlib_get_buffer (vm, pi0);
+	  // Terminate only local (SHG == 0) ARP
+	  if (vnet_buffer (p0)->l2.shg != 0)
+	    goto next_l2_feature;
+
+	  eth0 = vlib_buffer_get_current (p0);
+	  l3h0 = (u8 *) eth0 + vnet_buffer (p0)->l2.l2_len;
+	  ethertype0 = clib_net_to_host_u16 (*(u16 *) (l3h0 - 2));
+	  arp0 = (ethernet_arp_header_t *) l3h0;
+
+	  if (ethertype0 != ETHERNET_TYPE_ARP)
+	    goto check_ip6_nd;
+
+	  if ((arp0->opcode !=
+	       clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_request)) &&
+	      (arp0->opcode !=
+	       clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply)))
+	    goto check_ip6_nd;
+
+	  /* Must be ARP request/reply packet here */
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
+			     (p0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      u8 *t0 = vlib_add_trace (vm, node, p0,
+				       sizeof (ethernet_arp_input_trace_t));
+	      clib_memcpy_fast (t0, l3h0,
+				sizeof (ethernet_arp_input_trace_t));
+	    }
+
+	  error0 = 0;
+	  error0 =
+	    (arp0->l2_type !=
+	     clib_net_to_host_u16 (ETHERNET_ARP_HARDWARE_TYPE_ethernet)
+	     ? ETHERNET_ARP_ERROR_l2_type_not_ethernet : error0);
+	  error0 =
+	    (arp0->l3_type !=
+	     clib_net_to_host_u16 (ETHERNET_TYPE_IP4) ?
+	     ETHERNET_ARP_ERROR_l3_type_not_ip4 : error0);
+
+	  sw_if_index0 = vnet_buffer (p0)->sw_if_index[VLIB_RX];
+
+	  if (error0)
+	    goto drop;
+
+	  /* Trash ARP packets whose ARP-level source addresses do not
+	     match, or if requester address is mcast */
+	  if (PREDICT_FALSE
+	      (!ethernet_mac_address_equal (eth0->src_address,
+					    arp0->ip4_over_ethernet[0].
+					    mac.bytes))
+	      || ethernet_address_cast (arp0->ip4_over_ethernet[0].mac.bytes))
+	    {
+	      /* VRRP virtual MAC may be different to SMAC in ARP reply */
+	      if (!ethernet_mac_address_equal
+		  (arp0->ip4_over_ethernet[0].mac.bytes, vrrp_prefix))
+		{
+		  error0 = ETHERNET_ARP_ERROR_l2_address_mismatch;
+		  goto drop;
+		}
+	    }
+	  if (PREDICT_FALSE
+	      (ip4_address_is_multicast (&arp0->ip4_over_ethernet[0].ip4)))
+	    {
+	      error0 = ETHERNET_ARP_ERROR_l3_src_address_not_local;
+	      goto drop;
+	    }
+
+	  /* Check if anyone want ARP request events for L2 BDs */
+	  l2_arp_term_publish_v4_dp (sw_if_index0,
+				     &arp0->ip4_over_ethernet[0]);
+
+	  /* lookup BD mac_by_ip4 hash table for MAC entry */
+	  ip0 = arp0->ip4_over_ethernet[1].ip4.as_u32;
+	  bd_index0 = vnet_buffer (p0)->l2.bd_index;
+	  if (PREDICT_FALSE ((bd_index0 != last_bd_index)
+			     || (last_bd_index == (u16) ~ 0)))
+	    {
+	      last_bd_index = bd_index0;
+	      last_bd_config = vec_elt_at_index (l2im->bd_configs, bd_index0);
+	    }
+	  macp0 = (u8 *) hash_get (last_bd_config->mac_by_ip4, ip0);
+
+	  if (PREDICT_FALSE (!macp0))
+	    goto next_l2_feature;	/* MAC not found */
+	  if (PREDICT_FALSE (arp0->ip4_over_ethernet[0].ip4.as_u32 ==
+			     arp0->ip4_over_ethernet[1].ip4.as_u32))
+	    goto next_l2_feature;	/* GARP */
+
+	  /* MAC found, send ARP reply -
+	     Convert ARP request packet to ARP reply */
+	  arp0->opcode = clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply);
+	  arp0->ip4_over_ethernet[1] = arp0->ip4_over_ethernet[0];
+	  arp0->ip4_over_ethernet[0].ip4.as_u32 = ip0;
+	  mac_address_from_bytes (&arp0->ip4_over_ethernet[0].mac, macp0);
+	  clib_memcpy_fast (eth0->dst_address, eth0->src_address, 6);
+	  clib_memcpy_fast (eth0->src_address, macp0, 6);
+	  n_replies_sent += 1;
+
+	output_response:
+	  /* For BVI, need to use l2-fwd node to send ARP reply as
+	     l2-output node cannot output packet to BVI properly */
+	  cfg0 = vec_elt_at_index (l2im->configs, sw_if_index0);
+	  if (PREDICT_FALSE (cfg0->bvi))
+	    {
+	      vnet_buffer (p0)->l2.feature_bitmap |= L2INPUT_FEAT_FWD;
+	      vnet_buffer (p0)->sw_if_index[VLIB_RX] = 0;
+	      goto next_l2_feature;
+	    }
+
+	  /* Send ARP/ND reply back out input interface through l2-output */
+	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
+	  next0 = ARP_TERM_NEXT_L2_OUTPUT;
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					   to_next, n_left_to_next, pi0,
+					   next0);
+	  continue;
+
+	check_ip6_nd:
+	  /* IP6 ND event notification or solicitation handling to generate
+	     local response instead of flooding */
+	  iph0 = (ip6_header_t *) l3h0;
+	  if (PREDICT_FALSE (ethertype0 == ETHERNET_TYPE_IP6 &&
+			     iph0->protocol == IP_PROTOCOL_ICMP6 &&
+			     !ip6_address_is_unspecified
+			     (&iph0->src_address)))
+	    {
+	      sw_if_index0 = vnet_buffer (p0)->sw_if_index[VLIB_RX];
+	      if (vnet_ip6_nd_term
+		  (vm, node, p0, eth0, iph0, sw_if_index0,
+		   vnet_buffer (p0)->l2.bd_index))
+		goto output_response;
+	    }
+
+	next_l2_feature:
+	  {
+	    next0 = vnet_l2_feature_next (p0, arp_term_next_node_index,
+					  L2INPUT_FEAT_ARP_TERM);
+	    vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					     to_next, n_left_to_next,
+					     pi0, next0);
+	    continue;
+	  }
+
+	drop:
+	  if (0 == arp0->ip4_over_ethernet[0].ip4.as_u32 ||
+	      (arp0->ip4_over_ethernet[0].ip4.as_u32 ==
+	       arp0->ip4_over_ethernet[1].ip4.as_u32))
+	    {
+	      error0 = ETHERNET_ARP_ERROR_gratuitous_arp;
+	    }
+	  next0 = ARP_TERM_NEXT_DROP;
+	  p0->error = node->errors[error0];
+
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					   to_next, n_left_to_next, pi0,
+					   next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  vlib_error_count (vm, node->node_index,
+		    ETHERNET_ARP_ERROR_replies_sent, n_replies_sent);
+  return frame->n_vectors;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (arp_term_l2bd_node, static) = {
+  .function = arp_term_l2bd,
+  .name = "arp-term-l2bd",
+  .vector_size = sizeof (u32),
+  .n_errors = ETHERNET_ARP_N_ERROR,
+  .error_strings = ethernet_arp_error_strings,
+  .n_next_nodes = ARP_TERM_N_NEXT,
+  .next_nodes = {
+    [ARP_TERM_NEXT_L2_OUTPUT] = "l2-output",
+    [ARP_TERM_NEXT_DROP] = "error-drop",
+  },
+  .format_buffer = format_ethernet_arp_header,
+  .format_trace = format_arp_term_input_trace,
+};
+/* *INDENT-ON* */
+
+clib_error_t *
+arp_term_init (vlib_main_t * vm)
+{
+  // Initialize the feature next-node indexes
+  feat_bitmap_init_next_nodes (vm,
+			       arp_term_l2bd_node.index,
+			       L2INPUT_N_FEAT,
+			       l2input_get_feat_names (),
+			       arp_term_next_node_index);
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (arp_term_init);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */