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/**
* @file
* DNS-SD APIs used by LWIP_HOOK_NETCONN_EXTERNAL_RESOLVE
*
* This implementation assumes the DNS-SD API implementation (most likely provided by
* mDNSResponder) is implemented in the same process space as LwIP and can directly
* invoke the callback for DNSServiceGetAddrInfo. This is the typical deployment in
* an embedded environment where as a traditional OS requires pumping the callback results
* through an IPC mechanism (see DNSServiceRefSockFD/DNSServiceProcessResult)
*
* @defgroup dnssd DNS-SD
* @ingroup dns
*/
/*
* Copyright (c) 2017 Joel Cunningham, Garmin International, Inc. <joel.cunningham@garmin.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Joel Cunningham <joel.cunningham@me.com>
*
*/
#include "lwip/opt.h"
#include "lwip/err.h"
#include "lwip/inet.h"
#include "lwip/sockets.h"
#include "lwip/sys.h"
#include "dnssd.h"
/* External headers */
#include <string.h>
#include <dns_sd.h>
/* This timeout should allow for multiple queries.
mDNSResponder has the following query timeline:
Query 1: time = 0s
Query 2: time = 1s
Query 3: time = 4s
*/
#define GETADDR_TIMEOUT_MS 5000
#define LOCAL_DOMAIN ".local"
/* Only consume .local hosts */
#ifndef CONSUME_LOCAL_ONLY
#define CONSUME_LOCAL_ONLY 1
#endif
struct addr_clbk_msg {
sys_sem_t sem;
struct sockaddr_storage addr;
err_t err;
};
static void addr_info_callback(DNSServiceRef ref, DNSServiceFlags flags, u32_t interface_index,
DNSServiceErrorType error_code, char const* hostname,
const struct sockaddr* address, u32_t ttl, void* context);
int
lwip_dnssd_gethostbyname(const char *name, ip_addr_t *addr, u8_t addrtype, err_t *err)
{
DNSServiceErrorType result;
DNSServiceRef ref;
struct addr_clbk_msg msg;
char *p;
/* @todo: use with IPv6 */
LWIP_UNUSED_ARG(addrtype);
#if CONSUME_LOCAL_ONLY
/* check if this is a .local host. If it is, then we consume the query */
p = strstr(name, LOCAL_DOMAIN);
if (p == NULL) {
return 0; /* not consumed */
}
p += (sizeof(LOCAL_DOMAIN) - 1);
/* check to make sure .local isn't a substring (only allow .local\0 or .local.\0) */
if ((*p != '.' && *p != '\0') ||
(*p == '.' && *(p + 1) != '\0')) {
return 0; /* not consumed */
}
#endif /* CONSUME_LOCAL_ONLY */
msg.err = sys_sem_new(&msg.sem, 0);
if (msg.err != ERR_OK) {
goto query_done;
}
msg.err = ERR_TIMEOUT;
result = DNSServiceGetAddrInfo(&ref, 0, 0, kDNSServiceProtocol_IPv4, name, addr_info_callback, &msg);
if (result == kDNSServiceErr_NoError) {
sys_arch_sem_wait(&msg.sem, GETADDR_TIMEOUT_MS);
DNSServiceRefDeallocate(ref);
/* We got a response */
if (msg.err == ERR_OK) {
struct sockaddr_in* addr_in = (struct sockaddr_in *)&msg.addr;
if (addr_in->sin_family == AF_INET) {
inet_addr_to_ip4addr(ip_2_ip4(addr), &addr_in->sin_addr);
} else {
/* @todo add IPv6 support */
msg.err = ERR_VAL;
}
}
}
sys_sem_free(&msg.sem);
/* Query has been consumed and is finished */
query_done:
*err = msg.err;
return 1;
}
static void
addr_info_callback(DNSServiceRef ref, DNSServiceFlags flags, u32_t interface_index,
DNSServiceErrorType error_code, char const* hostname,
const struct sockaddr* address, u32_t ttl, void* context)
{
struct addr_clbk_msg* msg = (struct addr_clbk_msg*)context;
struct sockaddr_in* addr_in = (struct sockaddr_in *)address;
LWIP_UNUSED_ARG(ref);
LWIP_UNUSED_ARG(flags);
LWIP_UNUSED_ARG(interface_index);
LWIP_UNUSED_ARG(hostname);
LWIP_UNUSED_ARG(ttl);
LWIP_UNUSED_ARG(context);
if ((error_code == kDNSServiceErr_NoError) &&
(addr_in->sin_family == AF_INET)) {
MEMCPY(&msg->addr, addr_in, sizeof(*addr_in));
msg->err = ERR_OK;
}
else {
/* @todo add IPv6 support */
msg->err = ERR_VAL;
}
sys_sem_signal(&msg->sem);
} /* addr_info_callback() */
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