/
dialwithdns.go
144 lines (137 loc) · 3.18 KB
/
dialwithdns.go
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// Copyright (c) 2016-present Cloud <cloud@txthinking.com>
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of version 3 of the GNU General Public
// License as published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package dialwithdns
import (
"errors"
"net"
"strconv"
"strings"
"github.com/txthinking/brook"
"github.com/txthinking/socks5"
)
type DialWithDNS struct {
DNSClient *brook.DNSClient
DOHClient *brook.DOHClient
Prefer string
}
func NewDialWithDNS(dns, prefer string) (*DialWithDNS, error) {
if prefer != "A" && prefer != "AAAA" {
return nil, errors.New("Invalid prefer")
}
if !strings.HasPrefix(dns, "https://") {
return &DialWithDNS{DNSClient: &brook.DNSClient{Server: dns}, Prefer: prefer}, nil
}
dc, err := brook.NewDOHClient(dns)
if err != nil {
return nil, err
}
return &DialWithDNS{DOHClient: dc, Prefer: prefer}, nil
}
func (p *DialWithDNS) IP(domain string) (net.IP, error) {
if p.Prefer == "A" {
if p.DNSClient != nil {
ip, err := p.DNSClient.A(domain)
if err != nil {
return nil, err
}
if ip != nil {
return ip, nil
}
ip, err = p.DNSClient.AAAA(domain)
if err != nil {
return nil, err
}
if ip != nil {
return ip, nil
}
return nil, errors.New("Can not resolve " + domain)
}
if p.DOHClient != nil {
ip, err := p.DOHClient.A(domain)
if err != nil {
return nil, err
}
if ip != nil {
return ip, nil
}
ip, err = p.DOHClient.AAAA(domain)
if err != nil {
return nil, err
}
if ip != nil {
return ip, nil
}
return nil, errors.New("Can not resolve " + domain)
}
}
if p.DNSClient != nil {
ip, err := p.DNSClient.AAAA(domain)
if err != nil {
return nil, err
}
if ip != nil {
return ip, nil
}
ip, err = p.DNSClient.A(domain)
if err != nil {
return nil, err
}
if ip != nil {
return ip, nil
}
return nil, errors.New("Can not resolve " + domain)
}
if p.DOHClient != nil {
ip, err := p.DOHClient.AAAA(domain)
if err != nil {
return nil, err
}
if ip != nil {
return ip, nil
}
ip, err = p.DOHClient.A(domain)
if err != nil {
return nil, err
}
if ip != nil {
return ip, nil
}
return nil, errors.New("Can not resolve " + domain)
}
return nil, errors.New("Can not resolve " + domain)
}
func (p *DialWithDNS) TouchBrook() {
brook.Resolve = func(network string, addr string) (net.Addr, error) {
h, p1, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
port, err := strconv.Atoi(p1)
if err != nil {
return nil, err
}
ip := net.ParseIP(h)
if ip == nil {
ip, err = p.IP(h)
if err != nil {
return nil, err
}
}
if network == "tcp" {
return &net.TCPAddr{IP: ip, Port: port}, nil
}
return &net.UDPAddr{IP: ip, Port: port}, nil
}
socks5.Resolve = brook.Resolve
}