/* nsapi_dns.cpp
* Original work Copyright (c) 2013 Henry Leinen (henry[dot]leinen [at] online [dot] de)
* Modified work Copyright (c) 2015 ARM Limited
* SPDX-License-Identifier: Apache-2.0
*
* 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.
*/
/* Declare __STDC_LIMIT_MACROS so stdint.h defines INT32_MAX when using C++ */
#define __STDC_LIMIT_MACROS
#include "netsocket/nsapi_dns.h"
#include "netsocket/UDPSocket.h"
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include "events/mbed_shared_queues.h"
#include "events/EventQueue.h"
#include "netsocket/OnboardNetworkStack.h"
#include "rtos/Kernel.h"
#include "rtos/Mutex.h"
#include "SingletonPtr.h"
using namespace std::chrono;
using rtos::Kernel::Clock;
#define CLASS_IN 1
#define RR_A 1
#define RR_AAAA 28
// DNS options
#define DNS_BUFFER_SIZE 512
#define DNS_SERVERS_SIZE 5
#define DNS_RESPONSE_MIN_SIZE 12
#define DNS_STACK_SERVERS_NUM 5
#define DNS_QUERY_QUEUE_SIZE 5
#define DNS_HOST_NAME_MAX_LEN 255
#define DNS_TIMER_TIMEOUT 100
#if !defined(MIN)
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#endif
struct DNS_CACHE {
nsapi_addr_t *address;
char *host;
Clock::time_point expires; /*!< time to live in milliseconds */
Clock::time_point accessed; /*!< last accessed */
uint8_t count; /*!< number of IP addresses */
};
struct SOCKET_CB_DATA {
NetworkStack::call_in_callback_cb_t call_in_cb;
NetworkStack *stack;
};
enum dns_state {
DNS_CREATED, /*!< created, not yet making query to network */
DNS_INITIATED, /*!< making query to network */
DNS_CANCELLED /*!< cancelled, callback will not be called */
};
struct DNS_QUERY {
intptr_t unique_id;
nsapi_error_t status;
NetworkStack *stack;
char *host;
const char *interface_name;
NetworkStack::hostbyname_cb_t callback;
NetworkStack::call_in_callback_cb_t call_in_cb;
nsapi_size_t addr_count;
nsapi_version_t version;
UDPSocket *socket;
SOCKET_CB_DATA *socket_cb_data;
nsapi_addr_t *addrs;
duration<uint32_t> ttl;
uint32_t total_timeout;
uint32_t socket_timeout;
uint16_t dns_message_id;
uint8_t dns_server;
uint8_t retries;
uint8_t total_attempts;
uint8_t send_success;
uint8_t count;
dns_state state;
};
static void nsapi_dns_cache_add(const char *host, nsapi_addr_t *address, duration<uint32_t> ttl, uint8_t count);
static nsapi_size_or_error_t nsapi_dns_cache_find(const char *host, nsapi_version_t version, nsapi_addr_t *address);
static void nsapi_dns_cache_reset();
static nsapi_error_t nsapi_dns_get_server_addr(NetworkStack *stack, uint8_t *index, uint8_t *total_attempts, uint8_t *send_success, SocketAddress *dns_addr, const char *interface_name);
static void nsapi_dns_query_async_create(void *ptr);
static nsapi_error_t nsapi_dns_query_async_delete(intptr_t unique_id);
static void nsapi_dns_query_async_send(void *ptr);
static void nsapi_dns_query_async_timeout(void);
static void nsapi_dns_query_async_resp(DNS_QUERY *query, nsapi_error_t status, SocketAddress *address);
static void nsapi_dns_query_async_socket_callback(void *ptr);
static void nsapi_dns_query_async_socket_callback_handle(NetworkStack *stack);
static void nsapi_dns_query_async_response(void *ptr);
static void nsapi_dns_query_async_initiate_next(void);
// *INDENT-OFF*
static nsapi_addr_t dns_servers[DNS_SERVERS_SIZE] = {
{NSAPI_IPv4, {8, 8, 8, 8}}, // Google
{NSAPI_IPv6, {0x20,0x01, 0x48,0x60, 0x48,0x60, 0,0, // Google
0,0, 0,0, 0,0, 0x88,0x88}},
{NSAPI_IPv4, {209, 244, 0, 3}}, // Level 3
{NSAPI_IPv4, {84, 200, 69, 80}}, // DNS.WATCH
{NSAPI_IPv6, {0x20,0x01, 0x16,0x08, 0,0x10, 0,0x25, // DNS.WATCH
0,0, 0,0, 0x1c,0x04, 0xb1,0x2f}},
};
// *INDENT-ON*
#if (MBED_CONF_NSAPI_DNS_CACHE_SIZE > 0)
static DNS_CACHE *dns_cache[MBED_CONF_NSAPI_DNS_CACHE_SIZE];
// Protects cache shared between blocking and asynchronous calls
static SingletonPtr<rtos::Mutex> dns_cache_mutex;
#endif
static uint16_t dns_message_id = 1;
static intptr_t dns_unique_id = 1;
static DNS_QUERY *dns_query_queue[DNS_QUERY_QUEUE_SIZE];
// Protects from several threads running asynchronous DNS
static SingletonPtr<rtos::Mutex> dns_mutex;
static SingletonPtr<NetworkStack::call_in_callback_cb_t> dns_call_in;
static bool dns_timer_running = false;
// DNS server configuration
extern "C" nsapi_error_t nsapi_dns_add_server(nsapi_addr_t addr, const char *interface_name)
{
// check if addr was already added
for (int i = 0; i < DNS_SERVERS_SIZE; i++) {
if (memcmp(&addr, &dns_servers[i], sizeof(nsapi_addr_t)) == 0) {
return NSAPI_ERROR_OK;
}
}
memmove(&dns_servers[1], &dns_servers[0],
(DNS_SERVERS_SIZE - 1)*sizeof(nsapi_addr_t));
dns_servers[0] = addr;
return NSAPI_ERROR_OK;
}
// DNS packet parsing
static void dns_append_byte(uint8_t **p, uint8_t byte)
{
*(*p)++ = byte;
}
static void dns_append_word(uint8_t **p, uint16_t word)
{
dns_append_byte(p, 0xff & (word >> 8));
dns_append_byte(p, 0xff & (word >> 0));
}
static void dns_append_name(uint8_t **p, const char *name, uint8_t len)
{
dns_append_byte(p, len);
memcpy(*p, name, len);
*p += len;
}
static uint8_t dns_scan_byte(const uint8_t **p)
{
return *(*p)++;
}
static uint16_t dns_scan_word(const uint8_t **p)
{
uint16_t a = dns_scan_byte(p);
uint16_t b = dns_scan_byte(p);
return (a << 8) | b;
}
static uint32_t dns_scan_word32(const uint8_t **p)
{
uint32_t value = dns_scan_byte(p) << 24;
value |= dns_scan_byte(p) << 16;
value |= dns_scan_byte(p) << 8;
value |= dns_scan_byte(p);
return value;
}
static int dns_append_question(uint8_t *ptr, uint16_t id, const char *host, nsapi_version_t version)
{
uint8_t *s_ptr = ptr;
uint8_t **p = &ptr;
// fill the header
dns_append_word(p, id); // id = 1
dns_append_word(p, 0x0100); // flags = recursion required
dns_append_word(p, 1); // qdcount = 1
dns_append_word(p, 0); // ancount = 0
dns_append_word(p, 0); // nscount = 0
dns_append_word(p, 0); // arcount = 0
// fill out the question names
while (host[0]) {
size_t label_len = strcspn(host, ".");
dns_append_name(p, host, label_len);
host += label_len + (host[label_len] == '.');
}
dns_append_byte(p, 0);
// fill out question footer
if (version != NSAPI_IPv6) {
dns_append_word(p, RR_A); // qtype = ipv4
} else {
dns_append_word(p, RR_AAAA); // qtype = ipv6
}
dns_append_word(p, CLASS_IN);
return *p - s_ptr;
}
static int dns_scan_response(const uint8_t *ptr, uint16_t exp_id, duration<uint32_t> *ttl, nsapi_addr_t *addr, unsigned addr_count)
{
const uint8_t **p = &ptr;
// scan header
uint16_t id = dns_scan_word(p);
uint16_t flags = dns_scan_word(p);
bool qr = 0x1 & (flags >> 15);
uint8_t opcode = 0xf & (flags >> 11);
uint8_t rcode = 0xf & (flags >> 0);
uint16_t qdcount = dns_scan_word(p); // qdcount
uint16_t ancount = dns_scan_word(p); // ancount
dns_scan_word(p); // nscount
dns_scan_word(p); // arcount
// verify header is response to query
if (!(id == exp_id && qr && opcode == 0)) {
return -1;
}
if (rcode != 0) {
return 0;
}
// skip questions
for (int i = 0; i < qdcount; i++) {
while (true) {
uint8_t len = dns_scan_byte(p);
if (len == 0) {
break;
}
*p += len;
}
dns_scan_word(p); // qtype
dns_scan_word(p); // qclass
}
// scan each response
unsigned count = 0;
for (int i = 0; i < ancount && count < addr_count; i++) {
while (true) {
uint8_t len = dns_scan_byte(p);
if (len == 0) {
break;
} else if (len & 0xc0) { // this is link
dns_scan_byte(p);
break;
}
*p += len;
}
uint16_t rtype = dns_scan_word(p); // rtype
uint16_t rclass = dns_scan_word(p); // rclass
uint32_t ttl_val = dns_scan_word32(p); // ttl
uint16_t rdlength = dns_scan_word(p); // rdlength
if (i == 0) {
// Is interested only on first address that is stored to cache
if (ttl_val > INT32_MAX) {
ttl_val = INT32_MAX;
}
*ttl = duration<uint32_t>(ttl_val);
}
if (rtype == RR_A && rclass == CLASS_IN && rdlength == NSAPI_IPv4_BYTES) {
// accept A record
addr->version = NSAPI_IPv4;
for (int i = 0; i < NSAPI_IPv4_BYTES; i++) {
addr->bytes[i] = dns_scan_byte(p);
}
addr += 1;
count += 1;
} else if (rtype == RR_AAAA && rclass == CLASS_IN && rdlength == NSAPI_IPv6_BYTES) {
// accept AAAA record
addr->version = NSAPI_IPv6;
for (int i = 0; i < NSAPI_IPv6_BYTES; i++) {
addr->bytes[i] = dns_scan_byte(p);
}
addr += 1;
count += 1;
} else {
// skip unrecognized records
*p += rdlength;
}
}
return count;
}
static void nsapi_dns_cache_add(const char *host, nsapi_addr_t *address, duration<uint32_t> ttl, uint8_t count)
{
#if (MBED_CONF_NSAPI_DNS_CACHE_SIZE > 0)
// RFC 1034: if TTL is zero, entry is not added to cache
if (ttl == ttl.zero()) {
return;
}
// Checks if already cached
if (nsapi_dns_cache_find(host, address->version, NULL) == NSAPI_ERROR_OK) {
return;
}
dns_cache_mutex->lock();
int index = -1;
Clock::time_point accessed = Clock::time_point::max();
// Finds free or last accessed entry
for (int i = 0; i < MBED_CONF_NSAPI_DNS_CACHE_SIZE; i++) {
if (!dns_cache[i]) {
index = i;
break;
} else if (dns_cache[i]->accessed <= accessed) {
accessed = dns_cache[i]->accessed;
index = i;
}
}
if (index < 0) {
dns_cache_mutex->unlock();
return;
}
// Allocates in case entry is free, otherwise reuses
if (!dns_cache[index]) {
dns_cache[index] = new (std::nothrow) DNS_CACHE;
} else {
delete dns_cache[index]->host;
delete dns_cache[index]->address;
}
if (dns_cache[index]) {
dns_cache[index]->address = new (std::nothrow) nsapi_addr_t[count];
for (int i = 0; i < count; i++) {
dns_cache[index]->address[i] = address[i];
}
dns_cache[index]->count = count;
dns_cache[index]->host = new (std::nothrow) char[strlen(host) + 1];
strcpy(dns_cache[index]->host, host);
auto now = Clock::now();
dns_cache[index]->expires = now + ttl;
dns_cache[index]->accessed = now;
}
dns_cache_mutex->unlock();
#endif
}
static nsapi_size_or_error_t nsapi_dns_cache_find(const char *host, nsapi_version_t version, nsapi_addr_t *address)
{
nsapi_error_t ret_val = NSAPI_ERROR_NO_ADDRESS;
#if (MBED_CONF_NSAPI_DNS_CACHE_SIZE > 0)
dns_cache_mutex->lock();
for (int i = 0; i < MBED_CONF_NSAPI_DNS_CACHE_SIZE; i++) {
if (dns_cache[i]) {
auto now = Clock::now();
// Checks all entries for expired entries
if (now > dns_cache[i]->expires) {
delete dns_cache[i]->host;
delete dns_cache[i]->address;
delete dns_cache[i];
dns_cache[i] = NULL;
} else if ((version == NSAPI_UNSPEC || version == dns_cache[i]->address[0].version) && //only first IP address version check, others have the same version
strcmp(dns_cache[i]->host, host) == 0) {
if (address) {
ret_val = 0;
for (int count = 0; count < dns_cache[i]->count; count++) {
address[count] = dns_cache[i]->address[count];
ret_val++;
}
}
dns_cache[i]->accessed = now;
}
}
}
dns_cache_mutex->unlock();
#endif
return ret_val;
}
static void nsapi_dns_cache_reset()
{
#if (MBED_CONF_NSAPI_DNS_CACHE_SIZE > 0)
dns_cache_mutex->lock();
for (int i = 0; i < MBED_CONF_NSAPI_DNS_CACHE_SIZE; i++) {
if (dns_cache[i]) {
delete[] dns_cache[i]->host;
dns_cache[i]->host = NULL;
delete[] dns_cache[i]->address;
delete dns_cache[i];
dns_cache[i] = NULL;
}
}
dns_cache_mutex->unlock();
#endif
}
static nsapi_error_t nsapi_dns_get_server_addr(NetworkStack *stack, uint8_t *index, uint8_t *total_attempts, uint8_t *send_success, SocketAddress *dns_addr, const char *interface_name)
{
bool dns_addr_set = false;
if (*total_attempts == 0) {
return NSAPI_ERROR_NO_ADDRESS;
}
if (*index >= DNS_SERVERS_SIZE + DNS_STACK_SERVERS_NUM) {
// If there are total attempts left and send to has been successful at least once on this round
if (*total_attempts && *send_success) {
*index = 0;
*send_success = 0;
} else {
return NSAPI_ERROR_NO_ADDRESS;
}
}
if (*index < DNS_STACK_SERVERS_NUM) {
nsapi_error_t ret = stack->get_dns_server(*index, dns_addr, interface_name);
if (ret < 0) {
*index = DNS_STACK_SERVERS_NUM;
} else {
dns_addr_set = true;
}
}
if (!dns_addr_set) {
dns_addr->set_addr(dns_servers[*index - DNS_STACK_SERVERS_NUM]);
}
dns_addr->set_port(53);
return NSAPI_ERROR_OK;
}
// core query function
static nsapi_size_or_error_t nsapi_dns_query_multiple(NetworkStack *stack, const char *host,
nsapi_addr_t *addr, unsigned addr_count, const char *interface_name, nsapi_version_t version)
{
// check for valid host name
int host_len = host ? strlen(host) : 0;
if (host_len > DNS_HOST_NAME_MAX_LEN || host_len == 0) {
return NSAPI_ERROR_PARAMETER;
}
// check cache
nsapi_addr *tmp = new (std::nothrow) nsapi_addr_t [MBED_CONF_NSAPI_DNS_ADDRESSES_LIMIT];
int cached = nsapi_dns_cache_find(host, version, tmp);
if (cached > 0) {
unsigned int us_cached = cached;
for (unsigned int i = 0; i < MIN(us_cached, addr_count); i++) {
addr[i] = tmp[i];
}
delete [] tmp;
return MIN(us_cached, addr_count);
}
delete [] tmp;
// create a udp socket
UDPSocket socket;
int err = socket.open(stack);
if (err) {
return err;
}
socket.set_timeout(MBED_CONF_NSAPI_DNS_RESPONSE_WAIT_TIME);
if (interface_name != NULL) {
socket.setsockopt(NSAPI_SOCKET, NSAPI_BIND_TO_DEVICE, interface_name, NSAPI_INTERFACE_NAME_MAX_SIZE);
}
// create network packet
uint8_t *const packet = (uint8_t *)malloc(DNS_BUFFER_SIZE);
if (!packet) {
return NSAPI_ERROR_NO_MEMORY;
}
nsapi_size_or_error_t result = NSAPI_ERROR_DNS_FAILURE;
uint8_t retries = MBED_CONF_NSAPI_DNS_RETRIES;
uint8_t index = 0;
uint8_t total_attempts = MBED_CONF_NSAPI_DNS_TOTAL_ATTEMPTS;
uint8_t send_success = 0;
// check against each dns server
while (true) {
SocketAddress dns_addr;
err = nsapi_dns_get_server_addr(stack, &index, &total_attempts, &send_success, &dns_addr, interface_name);
if (err != NSAPI_ERROR_OK) {
break;
}
if (version != NSAPI_UNSPEC && (dns_addr.get_ip_version() != version)) {
retries = MBED_CONF_NSAPI_DNS_RETRIES;
index++;
continue;
}
// send the question
int len = dns_append_question(packet, 1, host, dns_addr.get_ip_version());
err = socket.sendto(dns_addr, packet, len);
// send may fail for various reasons, including wrong address type - move on
if (err < 0) {
// goes to next dns server
retries = MBED_CONF_NSAPI_DNS_RETRIES;
index++;
continue;
}
send_success++;
if (total_attempts) {
total_attempts--;
}
// recv the response
err = socket.recvfrom(NULL, packet, DNS_BUFFER_SIZE);
if (err == NSAPI_ERROR_WOULD_BLOCK) {
if (retries) {
// retries
retries--;
} else {
// goes to next dns server
retries = MBED_CONF_NSAPI_DNS_RETRIES;
index++;
}
continue;
} else if (err < 0) {
result = err;
break;
}
const uint8_t *response = packet;
duration<uint32_t> ttl;
int resp = dns_scan_response(response, 1, &ttl, addr, addr_count);
if (resp > 0) {
nsapi_dns_cache_add(host, addr, ttl, resp);
result = resp;
} else if (resp < 0) {
continue;
}
/* The DNS response is final, no need to check other servers */
break;
}
// clean up packet
free(packet);
// clean up udp
err = socket.close();
if (err) {
return err;
}
// return result
return result;
}
// convenience functions for other forms of queries
extern "C" nsapi_size_or_error_t nsapi_dns_query_multiple(nsapi_stack_t *stack, const char *host,
nsapi_addr_t *addr, nsapi_size_t addr_count, const char *interface_name, nsapi_version_t version)
{
NetworkStack *nstack = nsapi_create_stack(stack);
return nsapi_dns_query_multiple(nstack, host, addr, addr_count, interface_name, version);
}
nsapi_size_or_error_t nsapi_dns_query_multiple(NetworkStack *stack, const char *host,
SocketAddress *addresses, nsapi_size_t addr_count, const char *interface_name, nsapi_version_t version)
{
nsapi_addr_t *addrs = new (std::nothrow) nsapi_addr_t[addr_count];
if (!addrs) {
return NSAPI_ERROR_NO_MEMORY;
}
nsapi_size_or_error_t result = nsapi_dns_query_multiple(stack, host, addrs, addr_count, interface_name, version);
if (result > 0) {
for (int i = 0; i < result; i++) {
addresses[i].set_addr(addrs[i]);
}
}
delete[] addrs;
return result;
}
extern "C" nsapi_error_t nsapi_dns_query(nsapi_stack_t *stack, const char *host,
nsapi_addr_t *addr, nsapi_version_t version)
{
NetworkStack *nstack = nsapi_create_stack(stack);
nsapi_size_or_error_t result = nsapi_dns_query_multiple(nstack, host, addr, 1, NULL, version);
return (nsapi_error_t)((result > 0) ? 0 : result);
}
nsapi_error_t nsapi_dns_query(NetworkStack *stack, const char *host,
SocketAddress *address, nsapi_version_t version)
{
nsapi_addr_t addr;
nsapi_size_or_error_t result = nsapi_dns_query_multiple(stack, host, &addr, 1, NULL, version);
address->set_addr(addr);
return (nsapi_error_t)((result > 0) ? 0 : result);
}
nsapi_error_t nsapi_dns_query(NetworkStack *stack, const char *host,
SocketAddress *address, const char *interface_name, nsapi_version_t version)
{
nsapi_addr_t addr;
nsapi_size_or_error_t result = nsapi_dns_query_multiple(stack, host, &addr, 1, interface_name, version);
address->set_addr(addr);
return (nsapi_error_t)((result > 0) ? 0 : result);
}
nsapi_value_or_error_t nsapi_dns_query_async(NetworkStack *stack, const char *host,
NetworkStack::hostbyname_cb_t callback,
NetworkStack::call_in_callback_cb_t call_in_cb,
nsapi_version_t version)
{
return nsapi_dns_query_multiple_async(stack, host, callback, 0, call_in_cb, NULL, version);
}
nsapi_value_or_error_t nsapi_dns_query_async(NetworkStack *stack, const char *host,
NetworkStack::hostbyname_cb_t callback,
NetworkStack::call_in_callback_cb_t call_in_cb,
const char *interface_name, nsapi_version_t version)
{
return nsapi_dns_query_multiple_async(stack, host, callback, 0, call_in_cb, interface_name, version);
}
void nsapi_dns_call_in_set(NetworkStack::call_in_callback_cb_t callback)
{
*dns_call_in.get() = callback;
}
void nsapi_dns_reset()
{
nsapi_dns_cache_reset();
dns_message_id = 1;
dns_unique_id = 1;
}
nsapi_error_t nsapi_dns_call_in(NetworkStack::call_in_callback_cb_t cb, int delay, mbed::Callback<void()> func)
{
if (*dns_call_in.get()) {
dns_call_in->call(delay, func);
} else {
return cb(delay, func);
}
return NSAPI_ERROR_OK;
}
nsapi_value_or_error_t nsapi_dns_query_multiple_async(NetworkStack *stack, const char *host,
NetworkStack::hostbyname_cb_t callback, nsapi_size_t addr_count,
NetworkStack::call_in_callback_cb_t call_in_cb,
const char *interface_name, nsapi_version_t version)
{
dns_mutex->lock();
if (!stack) {
return NSAPI_ERROR_PARAMETER;
}
// check for valid host name
int host_len = host ? strlen(host) : 0;
if (host_len > DNS_HOST_NAME_MAX_LEN || host_len == 0) {
dns_mutex->unlock();
return NSAPI_ERROR_PARAMETER;
}
nsapi_addr *address = new (std::nothrow) nsapi_addr_t [MBED_CONF_NSAPI_DNS_ADDRESSES_LIMIT];
int cached = nsapi_dns_cache_find(host, version, address);
if (!addr_count) {
if (cached > 0) {
SocketAddress addr(*address);
dns_mutex->unlock();
callback(1, &addr);
delete[] address;
return NSAPI_ERROR_OK;
}
} else {
if (cached > 0) {
SocketAddress *addr = new (std::nothrow) SocketAddress [cached];
for (int i = 0; i < cached; i++) {
addr[i].set_addr(address[i]);
}
dns_mutex->unlock();
callback(cached, addr);
delete[] address;
delete[] addr;
return cached;
}
}
delete[] address;
int index = -1;
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (!dns_query_queue[i]) {
index = i;
break;
}
}
if (index < 0) {
dns_mutex->unlock();
return NSAPI_ERROR_NO_MEMORY;
}
DNS_QUERY *query = new (std::nothrow) DNS_QUERY;
if (!query) {
dns_mutex->unlock();
return NSAPI_ERROR_NO_MEMORY;
}
query->host = new (std::nothrow) char[host_len + 1];
if (!query->host) {
delete query;
dns_mutex->unlock();
return NSAPI_ERROR_NO_MEMORY;
}
strcpy(query->host, host);
query->status = NSAPI_ERROR_TIMEOUT;
query->callback = callback;
query->call_in_cb = call_in_cb;
query->stack = stack;
query->addr_count = addr_count;
query->version = version;
query->socket = NULL;
query->socket_cb_data = NULL;
query->addrs = NULL;
query->dns_server = 0;
query->retries = MBED_CONF_NSAPI_DNS_RETRIES + 1;
query->total_attempts = MBED_CONF_NSAPI_DNS_TOTAL_ATTEMPTS;
query->send_success = 0;
query->dns_message_id = 0;
query->socket_timeout = 0;
query->total_timeout = MBED_CONF_NSAPI_DNS_TOTAL_ATTEMPTS * MBED_CONF_NSAPI_DNS_RESPONSE_WAIT_TIME + 500;
query->count = 0;
query->state = DNS_CREATED;
query->interface_name = interface_name;
query->unique_id = dns_unique_id++;
if (query->unique_id > 0x7FFF) {
query->unique_id = 1;
}
int ongoing_queries = 0;
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (dns_query_queue[i]) {
if (!query->socket && dns_query_queue[i]->socket && dns_query_queue[i]->stack == query->stack) {
query->socket = dns_query_queue[i]->socket;
query->socket_cb_data = dns_query_queue[i]->socket_cb_data;
}
ongoing_queries++;
}
}
dns_query_queue[index] = query;
// Add some overhead based on number of ongoing queries
query->total_timeout += ongoing_queries * 500;
if (!dns_timer_running) {
if (nsapi_dns_call_in(query->call_in_cb, DNS_TIMER_TIMEOUT, mbed::callback(nsapi_dns_query_async_timeout)) != NSAPI_ERROR_OK) {
delete[] query->host;
delete query;
dns_query_queue[index] = NULL;
dns_mutex->unlock();
return NSAPI_ERROR_NO_MEMORY;
}
dns_timer_running = true;
}
// Initiates query
nsapi_dns_query_async_initiate_next();
dns_mutex->unlock();
return query->unique_id;
}
static void nsapi_dns_query_async_initiate_next(void)
{
intptr_t id = INTPTR_MAX;
DNS_QUERY *query = NULL;
// Trigger next query to start, find one that has been on queue longest
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (dns_query_queue[i]) {
if (dns_query_queue[i]->state == DNS_CREATED) {
if (dns_query_queue[i]->unique_id <= id) {
query = dns_query_queue[i];
id = dns_query_queue[i]->unique_id;
}
// If some query is already ongoing do not trigger
} else if (dns_query_queue[i]->state == DNS_INITIATED) {
query = NULL;
break;
}
}
}
if (query) {
query->state = DNS_INITIATED;
nsapi_dns_call_in(query->call_in_cb, 0, mbed::callback(nsapi_dns_query_async_create, reinterpret_cast<void *>(query->unique_id)));
}
}
static void nsapi_dns_query_async_timeout(void)
{
dns_mutex->lock();
DNS_QUERY *query = NULL;
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (dns_query_queue[i]) {
if (dns_query_queue[i]->state == DNS_CANCELLED) {
// Delete cancelled
nsapi_dns_query_async_delete(dns_query_queue[i]->unique_id);
nsapi_dns_query_async_initiate_next();
continue;
}
if (dns_query_queue[i]->total_timeout > DNS_TIMER_TIMEOUT) {
dns_query_queue[i]->total_timeout -= DNS_TIMER_TIMEOUT;
} else {
// If does not already have response, fails
if (dns_query_queue[i]->status == NSAPI_ERROR_TIMEOUT) {
dns_query_queue[i]->socket_timeout = 0;
nsapi_dns_call_in(dns_query_queue[i]->call_in_cb, 0, mbed::callback(nsapi_dns_query_async_response, reinterpret_cast<void *>(dns_query_queue[i]->unique_id)));
}
}
if (dns_query_queue[i]->socket_timeout > 0) {
if (dns_query_queue[i]->socket_timeout > DNS_TIMER_TIMEOUT) {
dns_query_queue[i]->socket_timeout -= DNS_TIMER_TIMEOUT;
} else {
// Retries
dns_query_queue[i]->socket_timeout = 0;
nsapi_dns_call_in(dns_query_queue[i]->call_in_cb, 0,
mbed::callback(nsapi_dns_query_async_send, reinterpret_cast<void *>(dns_query_queue[i]->unique_id)));
}
}
if (!query) {
query = dns_query_queue[i];
}
}
}
// Starts timer again
if (query) {
nsapi_dns_call_in(query->call_in_cb, DNS_TIMER_TIMEOUT, mbed::callback(nsapi_dns_query_async_timeout));
} else {
dns_timer_running = false;
}
dns_mutex->unlock();
}
nsapi_error_t nsapi_dns_query_async_cancel(nsapi_size_or_error_t id)
{
dns_mutex->lock();
DNS_QUERY *query = NULL;
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (dns_query_queue[i] && dns_query_queue[i]->unique_id == id) {
query = dns_query_queue[i];
break;
}
}
if (!query || query->state == DNS_CANCELLED) {
dns_mutex->unlock();
return NSAPI_ERROR_PARAMETER;
}
// Mark the query as cancelled, deleted by timer handler
query->state = DNS_CANCELLED;
// Do not call callback
query->callback = 0;
dns_mutex->unlock();
return NSAPI_ERROR_OK;
}
static void nsapi_dns_query_async_create(void *ptr)
{
dns_mutex->lock();
intptr_t unique_id = reinterpret_cast<intptr_t>(ptr);
DNS_QUERY *query = NULL;
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (dns_query_queue[i] && dns_query_queue[i]->unique_id == unique_id) {
query = dns_query_queue[i];
break;
}
}
if (!query || query->state == DNS_CANCELLED) {
// Cancel has been called
dns_mutex->unlock();
return;
}
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (dns_query_queue[i] && dns_query_queue[i] != query) {
if (!query->socket && dns_query_queue[i]->socket && dns_query_queue[i]->stack == query->stack) {
query->socket = dns_query_queue[i]->socket;
query->socket_cb_data = dns_query_queue[i]->socket_cb_data;
}
}
}
UDPSocket *socket;
if (query->socket) {
socket = query->socket;
} else {
socket = new (std::nothrow) UDPSocket;
if (!socket) {
nsapi_dns_query_async_resp(query, NSAPI_ERROR_NO_MEMORY, NULL);
return;
}
int err = socket->open(query->stack);
if (err) {
delete socket;
nsapi_dns_query_async_resp(query, err, NULL);
return;
}
socket->set_timeout(0);
if (query->interface_name != NULL) {
socket->setsockopt(NSAPI_SOCKET, NSAPI_BIND_TO_DEVICE, query->interface_name, NSAPI_INTERFACE_NAME_MAX_SIZE);
}
if (!query->socket_cb_data) {
query->socket_cb_data = new (std::nothrow) SOCKET_CB_DATA;
if (!query->socket_cb_data) {
delete socket;
nsapi_dns_query_async_resp(query, NSAPI_ERROR_NO_MEMORY, NULL);
return;
}
}
query->socket_cb_data->call_in_cb = query->call_in_cb;
query->socket_cb_data->stack = query->stack;
socket->sigio(mbed::callback(nsapi_dns_query_async_socket_callback, query->socket_cb_data));
query->socket = socket;
}
dns_mutex->unlock();
nsapi_dns_query_async_send(reinterpret_cast<void *>(query->unique_id));
}
static nsapi_error_t nsapi_dns_query_async_delete(intptr_t unique_id)
{
int index = -1;
DNS_QUERY *query = NULL;
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (dns_query_queue[i] && dns_query_queue[i]->unique_id == unique_id) {
query = dns_query_queue[i];
index = i;
break;
}
}
if (!query) {
return NSAPI_ERROR_PARAMETER;
}
bool close_socket = true;
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (dns_query_queue[i] && dns_query_queue[i] != query && dns_query_queue[i]->socket &&
dns_query_queue[i]->stack == query->stack) {
close_socket = false;
}
}
if (close_socket && query->socket) {
query->socket->close();
delete query->socket;
delete query->socket_cb_data;
}
if (query->addrs) {
delete[] query->addrs;
}
delete[] query->host;
delete query;
dns_query_queue[index] = NULL;
return NSAPI_ERROR_OK;
}
static void nsapi_dns_query_async_resp(DNS_QUERY *query, nsapi_error_t status, SocketAddress *address)
{
NetworkStack::hostbyname_cb_t callback = query->callback;
nsapi_dns_query_async_delete(query->unique_id);
nsapi_dns_query_async_initiate_next();
dns_mutex->unlock();
if (callback) {
callback(status, address);
}
}
static void nsapi_dns_query_async_send(void *ptr)
{
dns_mutex->lock();
intptr_t unique_id = reinterpret_cast<intptr_t>(ptr);
DNS_QUERY *query = NULL;
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (dns_query_queue[i] && dns_query_queue[i]->unique_id == unique_id) {
query = dns_query_queue[i];
break;
}
}
if (!query || query->state != DNS_INITIATED) {
// Cancel has been called
dns_mutex->unlock();
return;
}
if (query->retries) {
query->retries--;
} else {
query->dns_server++;
query->retries = MBED_CONF_NSAPI_DNS_RETRIES;
}
query->dns_message_id = dns_message_id++;
if (dns_message_id == 0) {
dns_message_id = 1;
}
// create network packet
uint8_t *packet = (uint8_t *)malloc(DNS_BUFFER_SIZE);
if (!packet) {
nsapi_dns_query_async_resp(query, NSAPI_ERROR_NO_MEMORY, NULL);
return;
}
while (true) {
SocketAddress dns_addr;
nsapi_size_or_error_t err = nsapi_dns_get_server_addr(query->stack, &(query->dns_server), &(query->total_attempts), &(query->send_success), &dns_addr, query->interface_name);
if (err != NSAPI_ERROR_OK) {
nsapi_dns_query_async_resp(query, NSAPI_ERROR_TIMEOUT, NULL);
free(packet);
return;
}
if (query->version != NSAPI_UNSPEC && dns_addr.get_ip_version() != query->version) {
query->dns_server++;
continue;
}
// send the question
int len = dns_append_question(packet, query->dns_message_id, query->host, dns_addr.get_ip_version());
err = query->socket->sendto(dns_addr, packet, len);
if (err < 0) {
if (err == NSAPI_ERROR_WOULD_BLOCK) {
nsapi_dns_call_in(query->call_in_cb, DNS_TIMER_TIMEOUT, mbed::callback(nsapi_dns_query_async_send, ptr));
free(packet);
dns_mutex->unlock();
return; // Timeout handler will retry the connection if possible
} else {
query->dns_server++;
}
} else {
break;
}
}
query->send_success++;
if (query->total_attempts) {
query->total_attempts--;
}
free(packet);
query->socket_timeout = MBED_CONF_NSAPI_DNS_RESPONSE_WAIT_TIME;
dns_mutex->unlock();
}
static void nsapi_dns_query_async_socket_callback(void *ptr)
{
SOCKET_CB_DATA *cb_data = static_cast<SOCKET_CB_DATA *>(ptr);
if (cb_data) {
nsapi_dns_call_in(cb_data->call_in_cb, 0, mbed::callback(nsapi_dns_query_async_socket_callback_handle, cb_data->stack));
}
}
static void nsapi_dns_query_async_socket_callback_handle(NetworkStack *stack)
{
UDPSocket *socket = NULL;
dns_mutex->lock();
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (dns_query_queue[i] && dns_query_queue[i]->stack == stack) {
socket = dns_query_queue[i]->socket;
break;
}
}
if (socket) {
// create network packet
uint8_t *packet = (uint8_t *)malloc(DNS_BUFFER_SIZE);
if (!packet) {
dns_mutex->unlock();
return;
}
while (true) {
// recv the response
nsapi_size_or_error_t size = socket->recvfrom(NULL, packet, DNS_BUFFER_SIZE);
if (size < DNS_RESPONSE_MIN_SIZE) {
break;
}
// gets id from response to associate with correct query
uint16_t id = (packet[0] << 8) | packet[1];
DNS_QUERY *query = NULL;
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (dns_query_queue[i] && dns_query_queue[i]->dns_message_id == id) {
query = dns_query_queue[i];
break;
}
}
if (!query || query->state != DNS_INITIATED) {
continue;
}
int requested_count = 1;
if (query->addr_count > 1) {
requested_count = query->addr_count;
}
query->addrs = new (std::nothrow) nsapi_addr_t[requested_count];
int resp = dns_scan_response(packet, id, &(query->ttl), query->addrs, requested_count);
// Ignore invalid responses
if (resp < 0) {
delete[] query->addrs;
query->addrs = 0;
} else {
query->count = resp;
query->status = NSAPI_ERROR_DNS_FAILURE; // Used in case failure, otherwise ok
query->socket_timeout = 0;
nsapi_dns_call_in(query->call_in_cb, 0, mbed::callback(nsapi_dns_query_async_response, reinterpret_cast<void *>(query->unique_id)));
}
}
free(packet);
}
dns_mutex->unlock();
}
static void nsapi_dns_query_async_response(void *ptr)
{
dns_mutex->lock();
intptr_t unique_id = reinterpret_cast<intptr_t>(ptr);
DNS_QUERY *query = NULL;
for (int i = 0; i < DNS_QUERY_QUEUE_SIZE; i++) {
if (dns_query_queue[i] && dns_query_queue[i]->unique_id == unique_id) {
query = dns_query_queue[i];
break;
}
}
if (query && query->state == DNS_INITIATED) {
SocketAddress *addresses = NULL;
nsapi_error_t status = query->status;
if (query->count > 0) {
addresses = new (std::nothrow) SocketAddress[query->count];
for (int i = 0; i < query->count; i++) {
addresses[i].set_addr(query->addrs[i]);
}
// Adds address to cache
nsapi_dns_cache_add(query->host, &(query->addrs[0]), query->ttl, query->count);
status = query->count;
}
nsapi_dns_query_async_resp(query, status, addresses);
delete[] addresses;
} else {
dns_mutex->unlock();
}
}
