VPP-1027: DNS name resolver

This patch is a plausible first-cut, suitable for initial testing by
vcl (host stack client library).

Main features;
- recursive name resolution
- multiple ip4/ip6 name servers
- cache size limit enforcement
  - currently limited to 65K
- ttl / aging
- static mapping support
- show / clear / debug CLI commands

Binary APIs provided for the following:
- add/delete name servers
- enable/disable the name cache
- resolve a name

To Do list:
- Respond to ip4/ip6 client DNS requests (vs. binary API requests)
- Perf / scale tuning
  - map pending transaction ids to pool indices, so the cache
    can (greatly) exceed 65K entries
- Security improvements
  - Use unpredictable dns transaction IDs, related to previous item
  - Make sure that response-packet src ip addresses match the server
- Add binary APIs
  - deliver raw response data to clients
  - control recursive name resolution
- Documentation

Change-Id: I48c373d5c05d7108ccd814d4055caf8c75ca10b7
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 43 insertions, 1 deletions

diff --git a/src/vpp/api/custom_dump.c b/src/vpp/api/custom_dump.c
index 3abf4cdd298..46ce0b2659c 100644
--- a/src/vpp/api/custom_dump.c
+++ b/src/vpp/api/custom_dump.c
@@ -3127,6 +3127,16 @@ static void *vl_api_lldp_config_t_print
   s = format (s, "system_name %s ", mp->system_name);
   s = format (s, "tx_hold %d ", ntohl (mp->tx_hold));
   s = format (s, "tx_interval %d ", ntohl (mp->tx_interval));
+  FINISH;
+}
+
+static void *vl_api_dns_enable_disable_t_print
+  (vl_api_dns_enable_disable_t * mp, void *handle)
+{
+  u8 *s;
+
+  s = format (0, "SCRIPT: dns_enable_disable ");
+  s = format (s, "%s ", mp->enable ? "enable" : "disable");
 
   FINISH;
 }
@@ -3160,6 +3170,35 @@ static void *vl_api_sw_interface_set_lldp_t_print
   FINISH;
 }
 
+static void *vl_api_dns_name_server_add_del_t_print
+  (vl_api_dns_name_server_add_del_t * mp, void *handle)
+{
+  u8 *s;
+
+  s = format (0, "SCRIPT: dns_name_server_add_del ");
+  if (mp->is_ip6)
+    s = format (s, "%U ", format_ip6_address,
+		(ip6_address_t *) mp->server_address);
+  else
+    s = format (s, "%U ", format_ip4_address,
+		(ip4_address_t *) mp->server_address);
+
+  if (mp->is_add == 0)
+    s = format (s, "del ");
+
+  FINISH;
+}
+
+static void *vl_api_dns_resolve_name_t_print
+  (vl_api_dns_resolve_name_t * mp, void *handle)
+{
+  u8 *s;
+
+  s = format (0, "SCRIPT: dns_resolve_name ");
+  s = format (s, "%s ", mp->name);
+  FINISH;
+}
+
 #define foreach_custom_print_no_arg_function                            \
 _(lisp_eid_table_vni_dump)                                              \
 _(lisp_map_resolver_dump)                                               \
@@ -3352,7 +3391,10 @@ _(P2P_ETHERNET_DEL, p2p_ethernet_del)					\
 _(TCP_CONFIGURE_SRC_ADDRESSES, tcp_configure_src_addresses)		\
 _(APP_NAMESPACE_ADD_DEL, app_namespace_add_del)                         \
 _(LLDP_CONFIG, lldp_config)                                             \
-_(SW_INTERFACE_SET_LLDP, sw_interface_set_lldp)
+_(SW_INTERFACE_SET_LLDP, sw_interface_set_lldp)				\
+_(DNS_ENABLE_DISABLE, dns_enable_disable)                               \
+_(DNS_NAME_SERVER_ADD_DEL, dns_name_server_add_del)                     \
+_(DNS_RESOLVE_NAME, dns_resolve_name)
   void
 vl_msg_api_custom_dump_configure (api_main_t * am)
 {