package resolvers import ( "time" "github.com/miekg/dns" "github.com/mr-karan/doggo/pkg/models" "github.com/sirupsen/logrus" ) // Options represent a set of common options // to configure a Resolver. type Options struct { Logger *logrus.Logger Nameservers []models.Nameserver UseIPv4 bool UseIPv6 bool SearchList []string Ndots int Timeout time.Duration Strategy string InsecureSkipVerify bool TLSHostname string } // Resolver implements the configuration for a DNS // Client. Different types of providers can load // a DNS Resolver satisfying this interface. type Resolver interface { Lookup(dns.Question) (Response, error) } // Response represents a custom output format // for DNS queries. It wraps metadata about the DNS query // and the DNS Answer as well. type Response struct { Answers []Answer `json:"answers"` Authorities []Authority `json:"authorities"` Questions []Question `json:"questions"` } type Question struct { Name string `json:"name"` Type string `json:"type"` Class string `json:"class"` } type Answer struct { Name string `json:"name"` Type string `json:"type"` Class string `json:"class"` TTL string `json:"ttl"` Address string `json:"address"` Status string `json:"status"` RTT string `json:"rtt"` Nameserver string `json:"nameserver"` } type Authority struct { Name string `json:"name"` Type string `json:"type"` Class string `json:"class"` TTL string `json:"ttl"` MName string `json:"mname"` Status string `json:"status"` RTT string `json:"rtt"` Nameserver string `json:"nameserver"` } // LoadResolvers loads differently configured // resolvers based on a list of nameserver. func LoadResolvers(opts Options) ([]Resolver, error) { // For each nameserver, initialise the correct resolver. rslvrs := make([]Resolver, 0, len(opts.Nameservers)) for _, ns := range opts.Nameservers { if ns.Type == models.DOHResolver { opts.Logger.Debug("initiating DOH resolver") rslvr, err := NewDOHResolver(ns.Address, opts) if err != nil { return rslvrs, err } rslvrs = append(rslvrs, rslvr) } if ns.Type == models.DOTResolver { opts.Logger.Debug("initiating DOT resolver") rslvr, err := NewClassicResolver(ns.Address, ClassicResolverOpts{ UseTLS: true, UseTCP: true, }, opts) if err != nil { return rslvrs, err } rslvrs = append(rslvrs, rslvr) } if ns.Type == models.TCPResolver { opts.Logger.Debug("initiating TCP resolver") rslvr, err := NewClassicResolver(ns.Address, ClassicResolverOpts{ UseTLS: false, UseTCP: true, }, opts) if err != nil { return rslvrs, err } rslvrs = append(rslvrs, rslvr) } if ns.Type == models.UDPResolver { opts.Logger.Debug("initiating UDP resolver") rslvr, err := NewClassicResolver(ns.Address, ClassicResolverOpts{ UseTLS: false, UseTCP: false, }, opts) if err != nil { return rslvrs, err } rslvrs = append(rslvrs, rslvr) } if ns.Type == models.DNSCryptResolver { opts.Logger.Debug("initiating DNSCrypt resolver") rslvr, err := NewDNSCryptResolver(ns.Address, DNSCryptResolverOpts{ UseTCP: false, }, opts) if err != nil { return rslvrs, err } rslvrs = append(rslvrs, rslvr) } if ns.Type == models.DOQResolver { opts.Logger.Debug("initiating DOQ resolver") rslvr, err := NewDOQResolver(ns.Address, opts) if err != nil { return rslvrs, err } rslvrs = append(rslvrs, rslvr) } } return rslvrs, nil }