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/*
* 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);
static void
resolve_event (dns_main_t * dm, f64 now, u8 * reply)
{
vlib_main_t *vm = dm->vlib_main;
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;
/* $$$ u16 limits cache to 65K entries, fix later multiple dst ports */
pool_index = clib_net_to_host_u16 (d->id);
dns_cache_lock (dm);
if (pool_is_free_index (dm->entries, pool_index))
{
vec_free (reply);
vlib_node_increment_counter (vm, dns46_reply_node.index,
DNS46_REPLY_ERROR_NO_ELT, 1);
dns_cache_unlock (dm);
return;
}
ep = pool_elt_at_index (dm->entries, pool_index);
if (ep->dns_response)
vec_free (ep->dns_response);
/* Handle [sic] recursion AKA CNAME indirection */
if (vnet_dns_cname_indirection_nolock (dm, ep, reply))
{
dns_cache_unlock (dm);
return;
}
/* Save the response */
ep->dns_response = reply;
/* Pick some sensible default. */
ep->expiration_time = now + 600.0;
if (vec_len (ep->dns_response))
ep->flags |= DNS_CACHE_ENTRY_FLAG_VALID;
/* Most likely, send 1 message */
for (i = 0; i < vec_len (ep->api_clients_to_notify); i++)
{
vl_api_registration_t *regp;
vl_api_dns_resolve_name_reply_t *rmp;
regp = vl_api_client_index_to_registration
(ep->api_clients_to_notify[i]);
if (regp == 0)
continue;
rmp = vl_msg_api_alloc (sizeof (*rmp) + vec_len (ep->dns_response));
rmp->_vl_msg_id = clib_host_to_net_u16 (VL_API_DNS_RESOLVE_NAME_REPLY);
rmp->context = ep->api_client_contexts[i];
min_ttl = ~0;
rv = vnet_dns_response_to_reply (ep->dns_response, rmp, &min_ttl);
if (min_ttl != ~0)
ep->expiration_time = now + min_ttl;
rmp->retval = clib_host_to_net_u32 (rv);
vl_msg_api_send (regp, (u8 *) rmp);
}
vec_free (ep->api_clients_to_notify);
vec_free (ep->api_client_contexts);
/* $$$ Add ip4/ip6 reply code */
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:
*/
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