1 /* 2 * Copyright (c) 2023, The OpenThread Authors. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. Neither the name of the copyright holder nor the 13 * names of its contributors may be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #ifndef OT_POSIX_PLATFORM_RESOLVER_HPP_ 30 #define OT_POSIX_PLATFORM_RESOLVER_HPP_ 31 32 #include <openthread/openthread-system.h> 33 #include <openthread/platform/dns.h> 34 35 #include <arpa/inet.h> 36 #include <sys/select.h> 37 38 #include "logger.hpp" 39 40 #if OPENTHREAD_CONFIG_DNS_UPSTREAM_QUERY_ENABLE 41 42 namespace ot { 43 namespace Posix { 44 45 class Resolver : public Logger<Resolver> 46 { 47 public: 48 static const char kLogModuleName[]; ///< Module name used for logging. 49 50 constexpr static ssize_t kMaxDnsMessageSize = 512; 51 constexpr static ssize_t kMaxUpstreamTransactionCount = 16; 52 constexpr static ssize_t kMaxUpstreamServerCount = 3; 53 54 /** 55 * Initialize the upstream DNS resolver. 56 */ 57 void Init(void); 58 59 /** 60 * Sends the query to the upstream. 61 * 62 * @param[in] aTxn A pointer to the OpenThread upstream DNS query transaction. 63 * @param[in] aQuery A pointer to a message for the payload of the DNS query. 64 */ 65 void Query(otPlatDnsUpstreamQuery *aTxn, const otMessage *aQuery); 66 67 /** 68 * Cancels a upstream DNS query transaction. 69 * 70 * @param[in] aTxn A pointer to the OpenThread upstream DNS query transaction. 71 */ 72 void Cancel(otPlatDnsUpstreamQuery *aTxn); 73 74 /** 75 * Updates the file descriptor sets with file descriptors used by the radio driver. 76 * 77 * @param[in,out] aContext The mainloop context. 78 */ 79 void UpdateFdSet(otSysMainloopContext &aContext); 80 81 /** 82 * Handles the result of select. 83 * 84 * @param[in] aContext The mainloop context. 85 */ 86 void Process(const otSysMainloopContext &aContext); 87 88 /** 89 * Sets whether to retrieve upstream DNS servers from "resolv.conf". 90 * 91 * @param[in] aEnabled TRUE if enable retrieving upstream DNS servers from "resolv.conf", FALSE otherwise. 92 */ SetResolvConfEnabled(bool aEnabled)93 void SetResolvConfEnabled(bool aEnabled) { mIsResolvConfEnabled = aEnabled; } 94 95 /** 96 * Sets the upstream DNS servers. 97 * 98 * @param[in] aUpstreamDnsServers A pointer to the list of upstream DNS server addresses. Each address could be an 99 * IPv6 address or an IPv4-mapped IPv6 address. 100 * @param[in] aNumServers The number of upstream DNS servers. 101 */ 102 void SetUpstreamDnsServers(const otIp6Address *aUpstreamDnsServers, int aNumServers); 103 104 private: 105 static constexpr uint64_t kDnsServerListNullCacheTimeoutMs = 1 * 60 * 1000; // 1 minute 106 static constexpr uint64_t kDnsServerListCacheTimeoutMs = 10 * 60 * 1000; // 10 minutes 107 108 struct Transaction 109 { 110 otPlatDnsUpstreamQuery *mThreadTxn; 111 int mUdpFd; 112 }; 113 114 static int CreateUdpSocket(void); 115 116 Transaction *GetTransaction(int aFd); 117 Transaction *GetTransaction(otPlatDnsUpstreamQuery *aThreadTxn); 118 Transaction *AllocateTransaction(otPlatDnsUpstreamQuery *aThreadTxn); 119 120 void ForwardResponse(Transaction *aTxn); 121 void CloseTransaction(Transaction *aTxn); 122 void FinishTransaction(int aFd); 123 void TryRefreshDnsServerList(void); 124 void LoadDnsServerListFromConf(void); 125 126 bool mIsResolvConfEnabled = true; 127 int mUpstreamDnsServerCount = 0; 128 in_addr_t mUpstreamDnsServerList[kMaxUpstreamServerCount]; 129 uint64_t mUpstreamDnsServerListFreshness = 0; 130 131 Transaction mUpstreamTransaction[kMaxUpstreamTransactionCount]; 132 }; 133 134 } // namespace Posix 135 } // namespace ot 136 137 #endif // OPENTHREAD_CONFIG_DNS_UPSTREAM_QUERY_ENABLE 138 139 #endif // OT_POSIX_PLATFORM_RESOLVER_HPP_ 140