Move the vnet cdp protocol implementation to a plugin

Add a binary API and debug cli to enable/disable cdp. cdp is disabled
by default.

Change-Id: I307c7e38dfda38e36ff3325f65de7036c34d89b1
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 504 insertions, 0 deletions

diff --git a/src/plugins/cdp/cdp_input.c b/src/plugins/cdp/cdp_input.c
new file mode 100644
index 00000000000..fa993b84def
--- /dev/null
+++ b/src/plugins/cdp/cdp_input.c
@@ -0,0 +1,504 @@
+/*
+ * Copyright (c) 2011-2016 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 <cdp/cdp.h>
+
+cdp_main_t cdp_main;
+
+#define DEBUG_TLV_DUMP 0	/* 1=> dump TLV's to stdout while processing them */
+
+/*
+ * ported from an unspecified Cisco cdp implementation.
+ * Compute / return in HOST byte order. 0 => good checksum.
+ */
+u16
+cdp_checksum (void *p, int count)
+{
+  u32 sum;
+  u16 i, *data;
+
+  data = p;
+  sum = 0;
+  while (count > 1)
+    {
+      sum += ntohs (*data);
+      data++;
+      count -= 2;
+    }
+
+  if (count > 0)
+    sum += *(char *) data;
+
+  while (sum >> 16)
+    {
+      sum = (sum & 0xFFFF) + (sum >> 16);
+    }
+
+  i = (i16) sum;
+  return (~i);
+}
+
+/* TLV handler table */
+typedef struct
+{
+  char *name;
+  u32 tlv_id;
+  void *format;
+  void *process;
+} tlv_handler_t;
+
+static tlv_handler_t tlv_handlers[];
+
+/* Display a generic TLV as a set of hex bytes */
+static u8 *
+format_generic_tlv (u8 * s, va_list * va)
+{
+  cdp_tlv_t *t = va_arg (*va, cdp_tlv_t *);
+  tlv_handler_t *h = &tlv_handlers[t->t];
+
+  s = format (s, "%s(%d): %U\n", h->name,
+	      t->t, format_hex_bytes, t->v, t->l - sizeof (*t));
+  return s;
+}
+
+/* Ignore / skip a TLV we don't support */
+static cdp_error_t
+process_generic_tlv (cdp_main_t * cm, cdp_neighbor_t * n, cdp_tlv_t * t)
+{
+#if DEBUG_TLV_DUMP > 0
+  fformat (stdout, "%U", format_generic_tlv, t);
+#endif
+
+  return CDP_ERROR_NONE;
+}
+
+/* print a text tlv */
+static u8 *
+format_text_tlv (u8 * s, va_list * va)
+{
+  cdp_tlv_t *t = va_arg (*va, cdp_tlv_t *);
+  tlv_handler_t *h = &tlv_handlers[t->t];
+  int i;
+
+  s = format (s, "%s(%d): ", h->name, t->t);
+
+  for (i = 0; i < (t->l - sizeof (*t)); i++)
+    vec_add1 (s, t->v[i]);
+
+  vec_add1 (s, '\n');
+  return s;
+}
+
+#if DEBUG_TLV_DUMP == 0
+/* gcc warning be gone */
+CLIB_UNUSED (static cdp_error_t
+	     process_text_tlv (cdp_main_t * cm, cdp_neighbor_t * n,
+			       cdp_tlv_t * t));
+#endif
+
+/* process / skip a generic text TLV that we don't support */
+static cdp_error_t
+process_text_tlv (cdp_main_t * cm, cdp_neighbor_t * n, cdp_tlv_t * t)
+{
+#if DEBUG_TLV_DUMP > 0
+  fformat (stdout, "%U\n", format_text_tlv, t);
+#endif
+
+  return CDP_ERROR_NONE;
+}
+
+/* per-TLV format function definitions */
+#define format_unused_tlv format_generic_tlv
+#define format_device_name_tlv format_text_tlv
+#define format_address_tlv format_generic_tlv
+#define format_port_id_tlv format_text_tlv
+#define format_capabilities_tlv format_generic_tlv
+#define format_version_tlv format_text_tlv
+#define format_platform_tlv format_text_tlv
+#define format_ipprefix_tlv format_generic_tlv
+#define format_hello_tlv format_generic_tlv
+#define format_vtp_domain_tlv format_generic_tlv
+#define format_native_vlan_tlv format_generic_tlv
+#define format_duplex_tlv format_generic_tlv
+#define format_appl_vlan_tlv format_generic_tlv
+#define format_trigger_tlv format_generic_tlv
+#define format_power_tlv format_generic_tlv
+#define format_mtu_tlv format_generic_tlv
+#define format_trust_tlv format_generic_tlv
+#define format_cos_tlv format_generic_tlv
+#define format_sysname_tlv format_generic_tlv
+#define format_sysobject_tlv format_generic_tlv
+#define format_mgmt_addr_tlv format_generic_tlv
+#define format_physical_loc_tlv format_generic_tlv
+#define format_mgmt_addr2_tlv format_generic_tlv
+#define format_power_requested_tlv format_generic_tlv
+#define format_power_available_tlv format_generic_tlv
+#define format_port_unidirectional_tlv format_generic_tlv
+#define format_unknown_28_tlv format_generic_tlv
+#define format_energywise_tlv format_generic_tlv
+#define format_unknown_30_tlv format_generic_tlv
+#define format_spare_poe_tlv format_generic_tlv
+
+/* tlv ID=0 is a mistake */
+static cdp_error_t
+process_unused_tlv (cdp_main_t * cm, cdp_neighbor_t * n, cdp_tlv_t * t)
+{
+  return CDP_ERROR_BAD_TLV;
+}
+
+/* list of text TLV's that we snapshoot */
+#define foreach_text_to_struct_tlv              \
+_(device_name,DEBUG_TLV_DUMP)                   \
+_(version,DEBUG_TLV_DUMP)                       \
+_(platform,DEBUG_TLV_DUMP)                      \
+_(port_id,DEBUG_TLV_DUMP)
+
+#define _(z,dbg)                                                        \
+static                                                                  \
+cdp_error_t process_##z##_tlv (cdp_main_t *cm, cdp_neighbor_t *n,       \
+                                  cdp_tlv_t *t)                         \
+{                                                                       \
+    int i;                                                              \
+    if (dbg)                                                            \
+       fformat(stdout, "%U\n", format_text_tlv, t);                     \
+                                                                        \
+    if (n->z)                                                           \
+        _vec_len(n->z) = 0;                                             \
+                                                                        \
+    for (i = 0; i < (t->l - sizeof (*t)); i++)                          \
+        vec_add1(n->z, t->v[i]);                                        \
+                                                                        \
+    vec_add1(n->z, 0);                                                  \
+                                                                        \
+    return CDP_ERROR_NONE;                                              \
+}
+
+foreach_text_to_struct_tlv
+#undef _
+#define process_address_tlv process_generic_tlv
+#define process_capabilities_tlv process_generic_tlv
+#define process_ipprefix_tlv process_generic_tlv
+#define process_hello_tlv process_generic_tlv
+#define process_vtp_domain_tlv process_generic_tlv
+#define process_native_vlan_tlv process_generic_tlv
+#define process_duplex_tlv process_generic_tlv
+#define process_appl_vlan_tlv process_generic_tlv
+#define process_trigger_tlv process_generic_tlv
+#define process_power_tlv process_generic_tlv
+#define process_mtu_tlv process_generic_tlv
+#define process_trust_tlv process_generic_tlv
+#define process_cos_tlv process_generic_tlv
+#define process_sysname_tlv process_generic_tlv
+#define process_sysobject_tlv process_generic_tlv
+#define process_mgmt_addr_tlv process_generic_tlv
+#define process_physical_loc_tlv process_generic_tlv
+#define process_mgmt_addr2_tlv process_generic_tlv
+#define process_power_requested_tlv process_generic_tlv
+#define process_power_available_tlv process_generic_tlv
+#define process_port_unidirectional_tlv process_generic_tlv
+#define process_unknown_28_tlv process_generic_tlv
+#define process_energywise_tlv process_generic_tlv
+#define process_unknown_30_tlv process_generic_tlv
+#define process_spare_poe_tlv process_generic_tlv
+static tlv_handler_t tlv_handlers[] = {
+#define _(a) {#a, CDP_TLV_##a, format_##a##_tlv, process_##a##_tlv},
+  foreach_cdp_tlv_type
+#undef _
+};
+
+#if DEBUG_TLV_DUMP == 0
+CLIB_UNUSED (static u8 * format_cdp_hdr (u8 * s, va_list * va));
+#endif
+
+static u8 *
+format_cdp_hdr (u8 * s, va_list * va)
+{
+  cdp_hdr_t *h = va_arg (*va, cdp_hdr_t *);
+
+  s = format (s, "version %d, ttl %d(secs), cksum 0x%04x\n",
+	      h->version, h->ttl, h->checksum);
+  return s;
+}
+
+static cdp_error_t
+process_cdp_hdr (cdp_main_t * cm, cdp_neighbor_t * n, cdp_hdr_t * h)
+{
+#if DEBUG_TLV_DUMP > 0
+  fformat (stdout, "%U", format_cdp_hdr, h);
+#endif
+
+  if (h->version != 1 && h->version != 2)
+    return CDP_ERROR_PROTOCOL_VERSION;
+
+  n->ttl_in_seconds = h->ttl;
+
+  return CDP_ERROR_NONE;
+}
+
+/* scan a cdp packet; header, then tlv's */
+static int
+cdp_packet_scan (cdp_main_t * cm, cdp_neighbor_t * n)
+{
+  u8 *cur = n->last_rx_pkt;
+  cdp_hdr_t *h;
+  cdp_tlv_t *tlv;
+  cdp_error_t e = CDP_ERROR_NONE;
+  tlv_handler_t *handler;
+  cdp_error_t (*fp) (cdp_main_t *, cdp_neighbor_t *, cdp_tlv_t *);
+  u16 computed_checksum;
+
+  computed_checksum = cdp_checksum (cur, vec_len (cur));
+
+  if (computed_checksum)
+    return CDP_ERROR_CHECKSUM;
+
+  h = (cdp_hdr_t *) cur;
+
+  e = process_cdp_hdr (cm, n, h);
+  if (e)
+    return e;
+
+  cur = (u8 *) (h + 1);
+
+  while (cur < n->last_rx_pkt + vec_len (n->last_rx_pkt) - 1)
+    {
+      tlv = (cdp_tlv_t *) cur;
+      tlv->t = ntohs (tlv->t);
+      tlv->l = ntohs (tlv->l);
+      if (tlv->t >= ARRAY_LEN (tlv_handlers))
+	return CDP_ERROR_BAD_TLV;
+      handler = &tlv_handlers[tlv->t];
+      fp = handler->process;
+      e = (*fp) (cm, n, tlv);
+      if (e)
+	return e;
+      /* tlv length includes (t, l) */
+      cur += tlv->l;
+    }
+
+  return CDP_ERROR_NONE;
+}
+
+/*
+ * cdp input routine
+ */
+cdp_error_t
+cdp_input (vlib_main_t * vm, vlib_buffer_t * b0, u32 bi0)
+{
+  cdp_main_t *cm = &cdp_main;
+  cdp_neighbor_t *n;
+  uword *p, nbytes;
+  cdp_error_t e;
+  uword last_packet_signature;
+
+  /* find or create a neighbor pool entry for the (sw) interface
+     upon which we received this pkt */
+  p = hash_get (cm->neighbor_by_sw_if_index,
+		vnet_buffer (b0)->sw_if_index[VLIB_RX]);
+
+  if (p == 0)
+    {
+      pool_get (cm->neighbors, n);
+      memset (n, 0, sizeof (*n));
+      n->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+      n->packet_template_index = (u8) ~ 0;
+      hash_set (cm->neighbor_by_sw_if_index, n->sw_if_index,
+		n - cm->neighbors);
+    }
+  else
+    {
+      n = pool_elt_at_index (cm->neighbors, p[0]);
+    }
+
+  /*
+   * typical clib idiom. Don't repeatedly allocate and free
+   * the per-neighbor rx buffer. Reset its apparent length to zero
+   * and reuse it.
+   */
+
+  if (n->last_rx_pkt)
+    _vec_len (n->last_rx_pkt) = 0;
+
+  /* cdp disabled on this interface, we're done */
+  if (n->disabled)
+    return CDP_ERROR_DISABLED;
+
+  /*
+   * Make sure the per-neighbor rx buffer is big enough to hold
+   * the data we're about to copy
+   */
+  vec_validate (n->last_rx_pkt, vlib_buffer_length_in_chain (vm, b0) - 1);
+
+  /*
+   * Coalesce / copy e the buffer chain into the per-neighbor
+   * rx buffer
+   */
+  nbytes = vlib_buffer_contents (vm, bi0, n->last_rx_pkt);
+  ASSERT (nbytes <= vec_len (n->last_rx_pkt));
+
+  /*
+   * Compute Jenkins hash of the new packet, decide if we need to
+   * actually parse through the TLV's. CDP packets are all identical,
+   * so unless we time out the peer, we don't need to process the packet.
+   */
+  last_packet_signature =
+    hash_memory (n->last_rx_pkt, vec_len (n->last_rx_pkt), 0xd00b);
+
+  if (n->last_packet_signature_valid &&
+      n->last_packet_signature == last_packet_signature)
+    {
+      e = CDP_ERROR_CACHE_HIT;
+    }
+  else
+    {
+      /* Actually scan the packet */
+      e = cdp_packet_scan (cm, n);
+      n->last_packet_signature_valid = 1;
+      n->last_packet_signature = last_packet_signature;
+    }
+
+  if (e == CDP_ERROR_NONE)
+    {
+      n->last_heard = vlib_time_now (vm);
+    }
+
+  return e;
+}
+
+/*
+ * setup neighbor hash table
+ */
+static clib_error_t *
+cdp_input_init (vlib_main_t * vm)
+{
+  clib_error_t *error;
+  cdp_main_t *cm = &cdp_main;
+  void vnet_cdp_node_reference (void);
+
+  vnet_cdp_node_reference ();
+
+  if ((error = vlib_call_init_function (vm, cdp_periodic_init)))
+    return error;
+
+  cm->vlib_main = vm;
+  cm->vnet_main = vnet_get_main ();
+  cm->neighbor_by_sw_if_index = hash_create (0, sizeof (uword));
+
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (cdp_input_init);
+
+
+static u8 *
+format_cdp_neighbors (u8 * s, va_list * va)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
+  cdp_main_t *cm = va_arg (*va, cdp_main_t *);
+  vnet_main_t *vnm = &vnet_main;
+  cdp_neighbor_t *n;
+  vnet_hw_interface_t *hw;
+
+  s = format (s,
+	      "%=25s %=15s %=25s %=10s\n",
+	      "Our Port", "Peer System", "Peer Port", "Last Heard");
+
+  /* *INDENT-OFF* */
+  pool_foreach (n, cm->neighbors,
+  ({
+    hw = vnet_get_sup_hw_interface (vnm, n->sw_if_index);
+
+    if (n->disabled == 0)
+      s = format (s, "%=25s %=15s %=25s %=10.1f\n",
+                  hw->name, n->device_name, n->port_id,
+                  n->last_heard);
+  }));
+  /* *INDENT-ON* */
+  return s;
+}
+
+static clib_error_t *
+show_cdp (vlib_main_t * vm,
+	  unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  cdp_main_t *cm = &cdp_main;
+
+  if (cm->enabled == 0)
+    vlib_cli_output (vm, "CDP is not enabled...");
+  else
+    vlib_cli_output (vm, "%U\n", format_cdp_neighbors, vm, cm);
+
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (show_cdp_command, static) = {
+  .path = "show cdp",
+  .short_help = "Show cdp command",
+  .function = show_cdp,
+};
+/* *INDENT-ON* */
+
+
+/*
+ * packet trace format function, very similar to
+ * cdp_packet_scan except that we call the per TLV format
+ * functions instead of the per TLV processing functions
+ */
+u8 *
+cdp_input_format_trace (u8 * s, va_list * args)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+  cdp_input_trace_t *t = va_arg (*args, cdp_input_trace_t *);
+  u8 *cur;
+  cdp_hdr_t *h;
+  cdp_tlv_t *tlv;
+  tlv_handler_t *handler;
+  u8 *(*fp) (cdp_tlv_t *);
+
+  cur = t->data;
+
+  h = (cdp_hdr_t *) cur;
+  s = format (s, "%U", format_cdp_hdr, h);
+
+  cur = (u8 *) (h + 1);
+
+  while (cur < t->data + t->len)
+    {
+      tlv = (cdp_tlv_t *) cur;
+      tlv->t = ntohs (tlv->t);
+      tlv->l = ntohs (tlv->l);
+      if (tlv->t >= ARRAY_LEN (tlv_handlers))
+	{
+	  s = format (s, "BAD_TLV\n");
+	  break;
+	}
+      handler = &tlv_handlers[tlv->t];
+      fp = handler->format;
+      s = format (s, "  %U", fp, tlv);
+      /* tlv length includes (t, l) */
+      cur += tlv->l;
+    }
+
+  return s;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */