7fa2d06c4a
This allows connections to DoH servers using their stamp, and adds support for DNSCrypt servers by the way.
81 lines
2.2 KiB
Go
81 lines
2.2 KiB
Go
package resolvers
|
|
|
|
import (
|
|
"github.com/ameshkov/dnscrypt"
|
|
"github.com/miekg/dns"
|
|
"github.com/sirupsen/logrus"
|
|
)
|
|
|
|
// DNSCryptResolver represents the config options for setting up a Resolver.
|
|
type DNSCryptResolver struct {
|
|
client *dnscrypt.Client
|
|
serverInfo *dnscrypt.ServerInfo
|
|
server string
|
|
resolverOptions Options
|
|
}
|
|
|
|
// DNSCryptResolverOpts holds options for setting up a DNSCrypt resolver.
|
|
type DNSCryptResolverOpts struct {
|
|
IPv4Only bool
|
|
IPv6Only bool
|
|
UseTLS bool
|
|
UseTCP bool
|
|
}
|
|
|
|
// NewDNSCryptResolver accepts a list of nameservers and configures a DNS resolver.
|
|
func NewDNSCryptResolver(server string, dnscryptOpts DNSCryptResolverOpts, resolverOpts Options) (Resolver, error) {
|
|
net := "udp"
|
|
if dnscryptOpts.UseTCP {
|
|
net = "tcp"
|
|
}
|
|
client := &dnscrypt.Client{Proto: net, AdjustPayloadSize: true}
|
|
serverInfo, _, err := client.Dial(server)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return &DNSCryptResolver{
|
|
client: client,
|
|
serverInfo: serverInfo,
|
|
server: server,
|
|
resolverOptions: resolverOpts,
|
|
}, nil
|
|
}
|
|
|
|
// Lookup takes a dns.Question and sends them to DNS Server.
|
|
// It parses the Response from the server in a custom output format.
|
|
func (r *DNSCryptResolver) Lookup(question dns.Question) (Response, error) {
|
|
var (
|
|
rsp Response
|
|
messages = prepareMessages(question, r.resolverOptions.Ndots, r.resolverOptions.SearchList)
|
|
)
|
|
for _, msg := range messages {
|
|
r.resolverOptions.Logger.WithFields(logrus.Fields{
|
|
"domain": msg.Question[0].Name,
|
|
"ndots": r.resolverOptions.Ndots,
|
|
"nameserver": r.serverInfo.ProviderName,
|
|
}).Debug("Attempting to resolve")
|
|
in, rtt, err := r.client.Exchange(&msg, r.serverInfo)
|
|
if err != nil {
|
|
return rsp, err
|
|
}
|
|
// pack questions in output.
|
|
for _, q := range msg.Question {
|
|
ques := Question{
|
|
Name: q.Name,
|
|
Class: dns.ClassToString[q.Qclass],
|
|
Type: dns.TypeToString[q.Qtype],
|
|
}
|
|
rsp.Questions = append(rsp.Questions, ques)
|
|
}
|
|
// get the authorities and answers.
|
|
output := parseMessage(in, rtt, r.server)
|
|
rsp.Authorities = output.Authorities
|
|
rsp.Answers = output.Answers
|
|
|
|
if len(output.Answers) > 0 {
|
|
// stop iterating the searchlist.
|
|
break
|
|
}
|
|
}
|
|
return rsp, nil
|
|
}
|