/**************************************************************************** * libc/netdb/lib_dnscache.c * * Copyright (C) 2007, 2009, 2012, 2014-2017 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "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 * COPYRIGHT OWNER OR CONTRIBUTORS 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. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include "netdb/lib_dns.h" /**************************************************************************** * Private Data ****************************************************************************/ static sem_t g_dns_sem; /* Protects g_seqno and DNS cache */ static bool g_dns_initialized; /* DNS data structures initialized */ /**************************************************************************** * Public Data ****************************************************************************/ #if defined(CONFIG_NETDB_DNSSERVER_IPv6) && !defined(CONFIG_NETDB_RESOLVCONF) /* This is the default IPv6 DNS server address */ static const uint16_t g_ipv6_hostaddr[8] = { HTONS(CONFIG_NETDB_DNSSERVER_IPv6ADDR_1), HTONS(CONFIG_NETDB_DNSSERVER_IPv6ADDR_2), HTONS(CONFIG_NETDB_DNSSERVER_IPv6ADDR_3), HTONS(CONFIG_NETDB_DNSSERVER_IPv6ADDR_4), HTONS(CONFIG_NETDB_DNSSERVER_IPv6ADDR_5), HTONS(CONFIG_NETDB_DNSSERVER_IPv6ADDR_6), HTONS(CONFIG_NETDB_DNSSERVER_IPv6ADDR_7), HTONS(CONFIG_NETDB_DNSSERVER_IPv6ADDR_8) }; #endif /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: dns_initialize * * Description: * Make sure that the DNS client has been properly initialized for use. * ****************************************************************************/ bool dns_initialize(void) { /* Have DNS data structures been initialized? */ if (!g_dns_initialized) { (void)nxsem_init(&g_dns_sem, 0, 1); g_dns_initialized = true; } #ifndef CONFIG_NETDB_RESOLVCONF /* Has the DNS server IP address been assigned? */ if (!g_dns_address) { #if defined(CONFIG_NETDB_DNSSERVER_IPv4) struct sockaddr_in addr4; int ret; /* No, configure the default IPv4 DNS server address */ addr4.sin_family = AF_INET; addr4.sin_port = HTONS(DNS_DEFAULT_PORT); addr4.sin_addr.s_addr = HTONL(CONFIG_NETDB_DNSSERVER_IPv4ADDR); ret = dns_add_nameserver((FAR struct sockaddr *)&addr4, sizeof(struct sockaddr_in)); if (ret < 0) { return false; } #elif defined(CONFIG_NETDB_DNSSERVER_IPv6) struct sockaddr_in6 addr6; int ret; /* No, configure the default IPv6 DNS server address */ addr6.sin6_family = AF_INET6; addr6.sin6_port = HTONS(DNS_DEFAULT_PORT); memcpy(addr6.sin6_addr.s6_addr, g_ipv6_hostaddr, 16); ret = dns_add_nameserver((FAR struct sockaddr *)&addr6, sizeof(struct sockaddr_in6)); if (ret < 0) { return false; } #else /* Then we are not ready to perform DNS queries */ return false; #endif } #endif /* !CONFIG_NETDB_RESOLVCONF */ return true; } /**************************************************************************** * Name: dns_semtake * * Description: * Take the DNS semaphore, ignoring errors do to the receipt of signals. * ****************************************************************************/ void dns_semtake(void) { int errcode = 0; int ret; do { ret = _SEM_WAIT(&g_dns_sem); if (ret < 0) { errcode = SEM_ERRNO(ret); DEBUGASSERT(errcode == EINTR); } } while (ret < 0 && errcode == EINTR); } /**************************************************************************** * Name: dns_semgive * * Description: * Release the DNS semaphore * ****************************************************************************/ void dns_semgive(void) { DEBUGVERIFY(_SEM_POST(&g_dns_sem)); }