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 */ 58 void Init(void); 59 60 /** 61 * Sends the query to the upstream. 62 * 63 * @param[in] aTxn A pointer to the OpenThread upstream DNS query transaction. 64 * @param[in] aQuery A pointer to a message for the payload of the DNS query. 65 * 66 */ 67 void Query(otPlatDnsUpstreamQuery *aTxn, const otMessage *aQuery); 68 69 /** 70 * Cancels a upstream DNS query transaction. 71 * 72 * @param[in] aTxn A pointer to the OpenThread upstream DNS query transaction. 73 * 74 */ 75 void Cancel(otPlatDnsUpstreamQuery *aTxn); 76 77 /** 78 * Updates the file descriptor sets with file descriptors used by the radio driver. 79 * 80 * @param[in,out] aContext The mainloop context. 81 * 82 */ 83 void UpdateFdSet(otSysMainloopContext &aContext); 84 85 /** 86 * Handles the result of select. 87 * 88 * @param[in] aContext The mainloop context. 89 * 90 */ 91 void Process(const otSysMainloopContext &aContext); 92 93 private: 94 static constexpr uint64_t kDnsServerListNullCacheTimeoutMs = 1 * 60 * 1000; // 1 minute 95 static constexpr uint64_t kDnsServerListCacheTimeoutMs = 10 * 60 * 1000; // 10 minutes 96 97 struct Transaction 98 { 99 otPlatDnsUpstreamQuery *mThreadTxn; 100 int mUdpFd; 101 }; 102 103 Transaction *GetTransaction(int aFd); 104 Transaction *GetTransaction(otPlatDnsUpstreamQuery *aThreadTxn); 105 Transaction *AllocateTransaction(otPlatDnsUpstreamQuery *aThreadTxn); 106 107 void ForwardResponse(Transaction *aTxn); 108 void CloseTransaction(Transaction *aTxn); 109 void FinishTransaction(int aFd); 110 void TryRefreshDnsServerList(void); 111 void LoadDnsServerListFromConf(void); 112 113 int mUpstreamDnsServerCount = 0; 114 in_addr_t mUpstreamDnsServerList[kMaxUpstreamServerCount]; 115 uint64_t mUpstreamDnsServerListFreshness = 0; 116 117 Transaction mUpstreamTransaction[kMaxUpstreamTransactionCount]; 118 }; 119 120 } // namespace Posix 121 } // namespace ot 122 123 #endif // OPENTHREAD_CONFIG_DNS_UPSTREAM_QUERY_ENABLE 124 125 #endif // OT_POSIX_PLATFORM_RESOLVER_HPP_ 126