src/vnet/dns/resolver_process.c - fdio/vpp - Gitiles

 /*
  * Copyright (c) 2017 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 <vnet/dns/dns.h>
 #include <vlibapi/api.h>
 #include <vlibmemory/api.h>

 #include <vlib/vlib.h>
 #include <vnet/vnet.h>

 #include <vnet/vnet_msg_enum.h>

 #define vl_typedefs		/* define message structures */
 #include <vnet/vnet_all_api_h.h>
 #undef vl_typedefs

 #define vl_endianfun		/* define message structures */
 #include <vnet/vnet_all_api_h.h>
 #undef vl_endianfun

 /* instantiate all the print functions we know about */
 #define vl_print(handle, ...) vlib_cli_output (handle, __VA_ARGS__)
 #define vl_printfun
 #include <vnet/vnet_all_api_h.h>
 #undef vl_printfun

 #include <vlibapi/api_helper_macros.h>

 vlib_node_registration_t dns_resolver_node;

 extern int
 vnet_dns_response_to_reply (u8 * response,
 			    vl_api_dns_resolve_name_reply_t * rmp,
 			    u32 * min_ttlp);
 extern int
 vnet_dns_response_to_name (u8 * response,
 			   vl_api_dns_resolve_ip_reply_t * rmp,
 			   u32 * min_ttlp);

 static void
 resolve_event (dns_main_t * dm, f64 now, u8 * reply)
 {
   vlib_main_t *vm = dm->vlib_main;
   dns_pending_request_t *pr;
   dns_header_t *d;
   u32 pool_index;
   dns_cache_entry_t *ep;
   u32 min_ttl;
   u16 flags;
   u16 rcode;
   int i;
   int rv = 0;

   d = (dns_header_t *) reply;
   flags = clib_net_to_host_u16 (d->flags);
   rcode = flags & DNS_RCODE_MASK;

   /* $$$ u16 limits cache to 65K entries, fix later multiple dst ports */
   pool_index = clib_net_to_host_u16 (d->id);
   dns_cache_lock (dm);

   if (pool_is_free_index (dm->entries, pool_index))
     {
       vec_free (reply);
       vlib_node_increment_counter (vm, dns46_reply_node.index,
 				   DNS46_REPLY_ERROR_NO_ELT, 1);
       dns_cache_unlock (dm);
       return;
     }

   ep = pool_elt_at_index (dm->entries, pool_index);

   if (ep->dns_response)
     vec_free (ep->dns_response);

   /* Handle [sic] recursion AKA CNAME indirection */
   rv = vnet_dns_cname_indirection_nolock (dm, pool_index, reply);

   /* CNAME found, further resolution pending, we're done here */
   if (rv > 0)
     {
       dns_cache_unlock (dm);
       return;
     }
   /* Server backfire: refused to answer, or sent zero replies */
   if (rv < 0)
     {
       /* Try a different server */
       if (ep->server_af /* ip6 */ )
 	{
 	  if (0)
 	    clib_warning ("Server %U failed to resolve '%s'",
 			  format_ip6_address,
 			  dm->ip6_name_servers + ep->server_rotor, ep->name);
 	  /* Any more servers to try? */
 	  if (ep->server_fails > 1 || vec_len (dm->ip6_name_servers) <= 1)
 	    {
 	      /* No, tell the client to go away */
 	      goto reply;
 	    }
 	  ep->retry_count = 0;
 	  ep->server_rotor++;
 	  ep->server_fails++;
 	  if (ep->server_rotor >= vec_len (dm->ip6_name_servers))
 	    ep->server_rotor = 0;
 	  if (0)
 	    clib_warning ("Try server %U", format_ip6_address,
 			  dm->ip6_name_servers + ep->server_rotor);
 	  vnet_dns_send_dns6_request
 	    (dm, ep, dm->ip6_name_servers + ep->server_rotor);
 	}
       else
 	{
 	  if (0)
 	    clib_warning ("Server %U failed to resolve '%s'",
 			  format_ip4_address,
 			  dm->ip4_name_servers + ep->server_rotor, ep->name);

 	  if (ep->server_fails > 1 || vec_len (dm->ip4_name_servers) <= 1)
 	    {
 	      /* No, tell the client to go away */
 	      goto reply;
 	    }
 	  ep->retry_count = 0;
 	  ep->server_rotor++;
 	  ep->server_fails++;
 	  if (ep->server_rotor >= vec_len (dm->ip4_name_servers))
 	    ep->server_rotor = 0;
 	  if (0)
 	    clib_warning ("Try server %U", format_ip4_address,
 			  dm->ip4_name_servers + ep->server_rotor);
 	  vnet_dns_send_dns4_request
 	    (dm, ep, dm->ip4_name_servers + ep->server_rotor);
 	}
       dns_cache_unlock (dm);
       return;
     }

 reply:
   /* Save the response */
   ep->dns_response = reply;
   /* Pick some sensible default. */
   ep->expiration_time = now + 600.0;
   if (vec_len (ep->dns_response))
     ep->flags |= DNS_CACHE_ENTRY_FLAG_VALID;

   /* Most likely, send 1 message */
   for (i = 0; i < vec_len (ep->pending_requests); i++)
     {
       vl_api_registration_t *regp;

       pr = vec_elt_at_index (ep->pending_requests, i);

       switch (pr->request_type)
 	{
 	case DNS_API_PENDING_NAME_TO_IP:
 	  {
 	    vl_api_dns_resolve_name_reply_t *rmp;
 	    regp = vl_api_client_index_to_registration (pr->client_index);
 	    if (regp == 0)
 	      continue;

 	    rmp = vl_msg_api_alloc (sizeof (*rmp));
 	    rmp->_vl_msg_id =
 	      clib_host_to_net_u16 (VL_API_DNS_RESOLVE_NAME_REPLY);
 	    rmp->context = pr->client_context;
 	    min_ttl = ~0;
 	    rv = vnet_dns_response_to_reply (ep->dns_response, rmp, &min_ttl);
 	    if (min_ttl != ~0)
 	      ep->expiration_time = now + min_ttl;
 	    rmp->retval = clib_host_to_net_u32 (rv);
 	    vl_api_send_msg (regp, (u8 *) rmp);
 	  }
 	  break;

 	case DNS_API_PENDING_IP_TO_NAME:
 	  {
 	    vl_api_dns_resolve_ip_reply_t *rmp;

 	    regp = vl_api_client_index_to_registration (pr->client_index);
 	    if (regp == 0)
 	      continue;

 	    rmp = vl_msg_api_alloc (sizeof (*rmp));
 	    rmp->_vl_msg_id =
 	      clib_host_to_net_u16 (VL_API_DNS_RESOLVE_IP_REPLY);
 	    rmp->context = pr->client_context;
 	    min_ttl = ~0;
 	    rv = vnet_dns_response_to_name (ep->dns_response, rmp, &min_ttl);
 	    if (min_ttl != ~0)
 	      ep->expiration_time = now + min_ttl;
 	    rmp->retval = clib_host_to_net_u32 (rv);
 	    vl_api_send_msg (regp, (u8 *) rmp);
 	  }
 	  break;

 	case DNS_PEER_PENDING_IP_TO_NAME:
 	case DNS_PEER_PENDING_NAME_TO_IP:
 	  if (pr->is_ip6)
 	    vnet_send_dns6_reply (dm, pr, ep, 0 /* allocate a buffer */ );
 	  else
 	    vnet_send_dns4_reply (dm, pr, ep, 0 /* allocate a buffer */ );
 	  break;
 	default:
 	  clib_warning ("request type %d unknown", pr->request_type);
 	  break;
 	}
     }
   vec_free (ep->pending_requests);

   for (i = 0; i < vec_len (dm->unresolved_entries); i++)
     {
       if (dm->unresolved_entries[i] == pool_index)
 	{
 	  vec_delete (dm->unresolved_entries, 1, i);
 	  goto found;
 	}
     }
   clib_warning ("pool index %d AWOL from unresolved vector", pool_index);

 found:
   /* Deal with bogus names, server issues, etc. */
   switch (rcode)
     {
     default:
     case DNS_RCODE_NO_ERROR:
       break;

     case DNS_RCODE_SERVER_FAILURE:
     case DNS_RCODE_NOT_IMPLEMENTED:
     case DNS_RCODE_REFUSED:
       if (ep->server_af == 0)
 	clib_warning ("name server %U backfire",
 		      format_ip4_address,
 		      dm->ip4_name_servers + ep->server_rotor);
       else
 	clib_warning ("name server %U backfire",
 		      format_ip6_address,
 		      dm->ip6_name_servers + ep->server_rotor);
       /* FALLTHROUGH */
     case DNS_RCODE_NAME_ERROR:
     case DNS_RCODE_FORMAT_ERROR:
       /* remove trash from the cache... */
       vnet_dns_delete_entry_by_index_nolock (dm, ep - dm->entries);
       break;
     }

   dns_cache_unlock (dm);
   return;
 }

 static void
 retry_scan (dns_main_t * dm, f64 now)
 {
   int i;
   dns_cache_entry_t *ep;

   for (i = 0; i < vec_len (dm->unresolved_entries); i++)
     {
       dns_cache_lock (dm);
       ep = pool_elt_at_index (dm->entries, dm->unresolved_entries[i]);

       ASSERT ((ep->flags & DNS_CACHE_ENTRY_FLAG_VALID) == 0);
       vnet_send_dns_request (dm, ep);
       dns_cache_unlock (dm);
     }
 }

 static uword
 dns_resolver_process (vlib_main_t * vm,
 		      vlib_node_runtime_t * rt, vlib_frame_t * f)
 {
   dns_main_t *dm = &dns_main;
   f64 now;
   f64 timeout = 1000.0;
   uword *event_data = 0;
   uword event_type;
   int i;

   while (1)
     {
       vlib_process_wait_for_event_or_clock (vm, timeout);

       now = vlib_time_now (vm);

       event_type = vlib_process_get_events (vm, (uword **) & event_data);

       switch (event_type)
 	{
 	  /* Send one of these when a resolution is pending */
 	case DNS_RESOLVER_EVENT_PENDING:
 	  timeout = 2.0;
 	  break;

 	case DNS_RESOLVER_EVENT_RESOLVED:
 	  for (i = 0; i < vec_len (event_data); i++)
 	    resolve_event (dm, now, (u8 *) event_data[i]);
 	  break;

 	case ~0:		/* timeout */
 	  retry_scan (dm, now);
 	  break;
 	}
       vec_reset_length (event_data);

       /* No work? Back to slow timeout mode... */
       if (vec_len (dm->unresolved_entries) == 0)
 	timeout = 1000.0;
     }
   return 0;			/* or not */
 }

 /* *INDENT-OFF* */
 VLIB_REGISTER_NODE (dns_resolver_node) =
 {
   .function = dns_resolver_process,
   .type = VLIB_NODE_TYPE_PROCESS,
   .name = "dns-resolver-process",
 };
 /* *INDENT-ON* */


 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* Copyright (c) 2017 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 <vnet/dns/dns.h>
	#include <vlibapi/api.h>
	#include <vlibmemory/api.h>

	#include <vlib/vlib.h>
	#include <vnet/vnet.h>

	#include <vnet/vnet_msg_enum.h>

	#define vl_typedefs /* define message structures */
	#include <vnet/vnet_all_api_h.h>
	#undef vl_typedefs

	#define vl_endianfun /* define message structures */
	#include <vnet/vnet_all_api_h.h>
	#undef vl_endianfun

	/* instantiate all the print functions we know about */
	#define vl_print(handle, ...) vlib_cli_output (handle, __VA_ARGS__)
	#define vl_printfun
	#include <vnet/vnet_all_api_h.h>
	#undef vl_printfun

	#include <vlibapi/api_helper_macros.h>

	vlib_node_registration_t dns_resolver_node;

	extern int
	vnet_dns_response_to_reply (u8 * response,
	vl_api_dns_resolve_name_reply_t * rmp,
	u32 * min_ttlp);
	extern int
	vnet_dns_response_to_name (u8 * response,
	vl_api_dns_resolve_ip_reply_t * rmp,
	u32 * min_ttlp);

	static void
	resolve_event (dns_main_t * dm, f64 now, u8 * reply)
	{
	vlib_main_t *vm = dm->vlib_main;
	dns_pending_request_t *pr;
	dns_header_t *d;
	u32 pool_index;
	dns_cache_entry_t *ep;
	u32 min_ttl;
	u16 flags;
	u16 rcode;
	int i;
	int rv = 0;

	d = (dns_header_t *) reply;
	flags = clib_net_to_host_u16 (d->flags);
	rcode = flags & DNS_RCODE_MASK;

	/* $$$ u16 limits cache to 65K entries, fix later multiple dst ports */
	pool_index = clib_net_to_host_u16 (d->id);
	dns_cache_lock (dm);

	if (pool_is_free_index (dm->entries, pool_index))
	{
	vec_free (reply);
	vlib_node_increment_counter (vm, dns46_reply_node.index,
	DNS46_REPLY_ERROR_NO_ELT, 1);
	dns_cache_unlock (dm);
	return;
	}

	ep = pool_elt_at_index (dm->entries, pool_index);

	if (ep->dns_response)
	vec_free (ep->dns_response);

	/* Handle [sic] recursion AKA CNAME indirection */
	rv = vnet_dns_cname_indirection_nolock (dm, pool_index, reply);

	/* CNAME found, further resolution pending, we're done here */
	if (rv > 0)
	{
	dns_cache_unlock (dm);
	return;
	}
	/* Server backfire: refused to answer, or sent zero replies */
	if (rv < 0)
	{
	/* Try a different server */
	if (ep->server_af /* ip6 */ )
	{
	if (0)
	clib_warning ("Server %U failed to resolve '%s'",
	format_ip6_address,
	dm->ip6_name_servers + ep->server_rotor, ep->name);
	/* Any more servers to try? */
	if (ep->server_fails > 1 \|\| vec_len (dm->ip6_name_servers) <= 1)
	{
	/* No, tell the client to go away */
	goto reply;
	}
	ep->retry_count = 0;
	ep->server_rotor++;
	ep->server_fails++;
	if (ep->server_rotor >= vec_len (dm->ip6_name_servers))
	ep->server_rotor = 0;
	if (0)
	clib_warning ("Try server %U", format_ip6_address,
	dm->ip6_name_servers + ep->server_rotor);
	vnet_dns_send_dns6_request
	(dm, ep, dm->ip6_name_servers + ep->server_rotor);
	}
	else
	{
	if (0)
	clib_warning ("Server %U failed to resolve '%s'",
	format_ip4_address,
	dm->ip4_name_servers + ep->server_rotor, ep->name);

	if (ep->server_fails > 1 \|\| vec_len (dm->ip4_name_servers) <= 1)
	{
	/* No, tell the client to go away */
	goto reply;
	}
	ep->retry_count = 0;
	ep->server_rotor++;
	ep->server_fails++;
	if (ep->server_rotor >= vec_len (dm->ip4_name_servers))
	ep->server_rotor = 0;
	if (0)
	clib_warning ("Try server %U", format_ip4_address,
	dm->ip4_name_servers + ep->server_rotor);
	vnet_dns_send_dns4_request
	(dm, ep, dm->ip4_name_servers + ep->server_rotor);
	}
	dns_cache_unlock (dm);
	return;
	}

	reply:
	/* Save the response */
	ep->dns_response = reply;
	/* Pick some sensible default. */
	ep->expiration_time = now + 600.0;
	if (vec_len (ep->dns_response))
	ep->flags \|= DNS_CACHE_ENTRY_FLAG_VALID;

	/* Most likely, send 1 message */
	for (i = 0; i < vec_len (ep->pending_requests); i++)
	{
	vl_api_registration_t *regp;

	pr = vec_elt_at_index (ep->pending_requests, i);

	switch (pr->request_type)
	{
	case DNS_API_PENDING_NAME_TO_IP:
	{
	vl_api_dns_resolve_name_reply_t *rmp;
	regp = vl_api_client_index_to_registration (pr->client_index);
	if (regp == 0)
	continue;

	rmp = vl_msg_api_alloc (sizeof (*rmp));
	rmp->_vl_msg_id =
	clib_host_to_net_u16 (VL_API_DNS_RESOLVE_NAME_REPLY);
	rmp->context = pr->client_context;
	min_ttl = ~0;
	rv = vnet_dns_response_to_reply (ep->dns_response, rmp, &min_ttl);
	if (min_ttl != ~0)
	ep->expiration_time = now + min_ttl;
	rmp->retval = clib_host_to_net_u32 (rv);
	vl_api_send_msg (regp, (u8 *) rmp);
	}
	break;

	case DNS_API_PENDING_IP_TO_NAME:
	{
	vl_api_dns_resolve_ip_reply_t *rmp;

	regp = vl_api_client_index_to_registration (pr->client_index);
	if (regp == 0)
	continue;

	rmp = vl_msg_api_alloc (sizeof (*rmp));
	rmp->_vl_msg_id =
	clib_host_to_net_u16 (VL_API_DNS_RESOLVE_IP_REPLY);
	rmp->context = pr->client_context;
	min_ttl = ~0;
	rv = vnet_dns_response_to_name (ep->dns_response, rmp, &min_ttl);
	if (min_ttl != ~0)
	ep->expiration_time = now + min_ttl;
	rmp->retval = clib_host_to_net_u32 (rv);
	vl_api_send_msg (regp, (u8 *) rmp);
	}
	break;

	case DNS_PEER_PENDING_IP_TO_NAME:
	case DNS_PEER_PENDING_NAME_TO_IP:
	if (pr->is_ip6)
	vnet_send_dns6_reply (dm, pr, ep, 0 /* allocate a buffer */ );
	else
	vnet_send_dns4_reply (dm, pr, ep, 0 /* allocate a buffer */ );
	break;
	default:
	clib_warning ("request type %d unknown", pr->request_type);
	break;
	}
	}
	vec_free (ep->pending_requests);

	for (i = 0; i < vec_len (dm->unresolved_entries); i++)
	{
	if (dm->unresolved_entries[i] == pool_index)
	{
	vec_delete (dm->unresolved_entries, 1, i);
	goto found;
	}
	}
	clib_warning ("pool index %d AWOL from unresolved vector", pool_index);

	found:
	/* Deal with bogus names, server issues, etc. */
	switch (rcode)
	{
	default:
	case DNS_RCODE_NO_ERROR:
	break;

	case DNS_RCODE_SERVER_FAILURE:
	case DNS_RCODE_NOT_IMPLEMENTED:
	case DNS_RCODE_REFUSED:
	if (ep->server_af == 0)
	clib_warning ("name server %U backfire",
	format_ip4_address,
	dm->ip4_name_servers + ep->server_rotor);
	else
	clib_warning ("name server %U backfire",
	format_ip6_address,
	dm->ip6_name_servers + ep->server_rotor);
	/* FALLTHROUGH */
	case DNS_RCODE_NAME_ERROR:
	case DNS_RCODE_FORMAT_ERROR:
	/* remove trash from the cache... */
	vnet_dns_delete_entry_by_index_nolock (dm, ep - dm->entries);
	break;
	}

	dns_cache_unlock (dm);
	return;
	}

	static void
	retry_scan (dns_main_t * dm, f64 now)
	{
	int i;
	dns_cache_entry_t *ep;

	for (i = 0; i < vec_len (dm->unresolved_entries); i++)
	{
	dns_cache_lock (dm);
	ep = pool_elt_at_index (dm->entries, dm->unresolved_entries[i]);

	ASSERT ((ep->flags & DNS_CACHE_ENTRY_FLAG_VALID) == 0);
	vnet_send_dns_request (dm, ep);
	dns_cache_unlock (dm);
	}
	}

	static uword
	dns_resolver_process (vlib_main_t * vm,
	vlib_node_runtime_t * rt, vlib_frame_t * f)
	{
	dns_main_t *dm = &dns_main;
	f64 now;
	f64 timeout = 1000.0;
	uword *event_data = 0;
	uword event_type;
	int i;

	while (1)
	{
	vlib_process_wait_for_event_or_clock (vm, timeout);

	now = vlib_time_now (vm);

	event_type = vlib_process_get_events (vm, (uword **) & event_data);

	switch (event_type)
	{
	/* Send one of these when a resolution is pending */
	case DNS_RESOLVER_EVENT_PENDING:
	timeout = 2.0;
	break;

	case DNS_RESOLVER_EVENT_RESOLVED:
	for (i = 0; i < vec_len (event_data); i++)
	resolve_event (dm, now, (u8 *) event_data[i]);
	break;

	case ~0: /* timeout */
	retry_scan (dm, now);
	break;
	}
	vec_reset_length (event_data);

	/* No work? Back to slow timeout mode... */
	if (vec_len (dm->unresolved_entries) == 0)
	timeout = 1000.0;
	}
	return 0; /* or not */
	}

	/* INDENT-OFF */
	VLIB_REGISTER_NODE (dns_resolver_node) =
	{
	.function = dns_resolver_process,
	.type = VLIB_NODE_TYPE_PROCESS,
	.name = "dns-resolver-process",
	};
	/* INDENT-ON */


	/*
	* fd.io coding-style-patch-verification: ON
	*
	* Local Variables:
	* eval: (c-set-style "gnu")
	* End:
	*/