1 /* 2 * nghttp2 - HTTP/2 C Library 3 * 4 * Copyright (c) 2016 Tatsuhiro Tsujikawa 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining 7 * a copy of this software and associated documentation files (the 8 * "Software"), to deal in the Software without restriction, including 9 * without limitation the rights to use, copy, modify, merge, publish, 10 * distribute, sublicense, and/or sell copies of the Software, and to 11 * permit persons to whom the Software is furnished to do so, subject to 12 * the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be 15 * included in all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 19 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 20 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 21 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 22 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 23 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 24 */ 25 #ifndef SHRPX_DUAL_DNS_RESOLVER_H 26 #define SHRPX_DUAL_DNS_RESOLVER_H 27 28 #include "shrpx.h" 29 30 #include <ev.h> 31 32 #include "shrpx_dns_resolver.h" 33 34 using namespace nghttp2; 35 36 namespace shrpx { 37 38 // DualDNSResolver performs name resolution for both A and AAAA 39 // records at the same time. The first successful return (or if we 40 // have both successful results, prefer to AAAA) is chosen. This is 41 // wrapper around 2 DNSResolver inside. resolve(), get_status(), and 42 // how CompleteCb is called have the same semantics with DNSResolver. 43 class DualDNSResolver { 44 public: 45 // |family| controls IP version preference. If |family| == 46 // AF_UNSPEC, bot A and AAAA lookups are performed. If |family| == 47 // AF_INET, only A lookup is performed. If |family| == AF_INET6, 48 // only AAAA lookup is performed. 49 DualDNSResolver(struct ev_loop *loop, int family); 50 51 // Resolves |host|. |host| must be NULL-terminated string. 52 int resolve(const StringRef &host); 53 CompleteCb get_complete_cb() const; 54 void set_complete_cb(CompleteCb cb); 55 DNSResolverStatus get_status(Address *result) const; 56 57 private: 58 // IP version preference. 59 int family_; 60 // For A record 61 DNSResolver resolv4_; 62 // For AAAA record 63 DNSResolver resolv6_; 64 CompleteCb complete_cb_; 65 }; 66 67 } // namespace shrpx 68 69 #endif // SHRPX_DUAL_DNS_RESOLVER_H 70