mirror of
https://github.com/v2fly/v2ray-core.git
synced 2024-12-22 18:17:52 -05:00
329 lines
6.5 KiB
Go
329 lines
6.5 KiB
Go
package dns
|
|
|
|
import (
|
|
"context"
|
|
"sync"
|
|
"sync/atomic"
|
|
"time"
|
|
|
|
"github.com/miekg/dns"
|
|
|
|
"v2ray.com/core/common"
|
|
"v2ray.com/core/common/buf"
|
|
"v2ray.com/core/common/net"
|
|
"v2ray.com/core/common/session"
|
|
"v2ray.com/core/common/signal/pubsub"
|
|
"v2ray.com/core/common/task"
|
|
"v2ray.com/core/features/routing"
|
|
"v2ray.com/core/transport/internet/udp"
|
|
)
|
|
|
|
var (
|
|
multiQuestionDNS = map[net.Address]bool{
|
|
net.IPAddress([]byte{8, 8, 8, 8}): true,
|
|
net.IPAddress([]byte{8, 8, 4, 4}): true,
|
|
net.IPAddress([]byte{9, 9, 9, 9}): true,
|
|
}
|
|
)
|
|
|
|
type IPRecord struct {
|
|
IP net.IP
|
|
Expire time.Time
|
|
}
|
|
|
|
type pendingRequest struct {
|
|
domain string
|
|
expire time.Time
|
|
}
|
|
|
|
type ClassicNameServer struct {
|
|
sync.RWMutex
|
|
address net.Destination
|
|
ips map[string][]IPRecord
|
|
requests map[uint16]pendingRequest
|
|
pub *pubsub.Service
|
|
udpServer *udp.Dispatcher
|
|
cleanup *task.Periodic
|
|
reqID uint32
|
|
clientIP net.IP
|
|
}
|
|
|
|
func NewClassicNameServer(address net.Destination, dispatcher routing.Dispatcher, clientIP net.IP) *ClassicNameServer {
|
|
s := &ClassicNameServer{
|
|
address: address,
|
|
ips: make(map[string][]IPRecord),
|
|
requests: make(map[uint16]pendingRequest),
|
|
clientIP: clientIP,
|
|
pub: pubsub.NewService(),
|
|
}
|
|
s.cleanup = &task.Periodic{
|
|
Interval: time.Minute,
|
|
Execute: s.Cleanup,
|
|
}
|
|
s.udpServer = udp.NewDispatcher(dispatcher, s.HandleResponse)
|
|
return s
|
|
}
|
|
|
|
func (s *ClassicNameServer) Cleanup() error {
|
|
now := time.Now()
|
|
s.Lock()
|
|
defer s.Unlock()
|
|
|
|
if len(s.ips) == 0 && len(s.requests) == 0 {
|
|
return newError("nothing to do. stopping...")
|
|
}
|
|
|
|
for domain, ips := range s.ips {
|
|
newIPs := make([]IPRecord, 0, len(ips))
|
|
for _, ip := range ips {
|
|
if ip.Expire.After(now) {
|
|
newIPs = append(newIPs, ip)
|
|
}
|
|
}
|
|
if len(newIPs) == 0 {
|
|
delete(s.ips, domain)
|
|
} else if len(newIPs) < len(ips) {
|
|
s.ips[domain] = newIPs
|
|
}
|
|
}
|
|
|
|
if len(s.ips) == 0 {
|
|
s.ips = make(map[string][]IPRecord)
|
|
}
|
|
|
|
for id, req := range s.requests {
|
|
if req.expire.Before(now) {
|
|
delete(s.requests, id)
|
|
}
|
|
}
|
|
|
|
if len(s.requests) == 0 {
|
|
s.requests = make(map[uint16]pendingRequest)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (s *ClassicNameServer) HandleResponse(ctx context.Context, payload *buf.Buffer) {
|
|
msg := new(dns.Msg)
|
|
err := msg.Unpack(payload.Bytes())
|
|
if err == dns.ErrTruncated {
|
|
newError("truncated message received. DNS server should still work. If you see anything abnormal, please submit an issue to v2ray-core.").AtWarning().WriteToLog()
|
|
} else if err != nil {
|
|
newError("failed to parse DNS response").Base(err).AtWarning().WriteToLog()
|
|
return
|
|
}
|
|
|
|
id := msg.Id
|
|
s.Lock()
|
|
req, f := s.requests[id]
|
|
if f {
|
|
delete(s.requests, id)
|
|
}
|
|
s.Unlock()
|
|
|
|
if !f {
|
|
return
|
|
}
|
|
|
|
domain := req.domain
|
|
ips := make([]IPRecord, 0, 16)
|
|
|
|
now := time.Now()
|
|
for _, rr := range msg.Answer {
|
|
var ip net.IP
|
|
ttl := rr.Header().Ttl
|
|
switch rr := rr.(type) {
|
|
case *dns.A:
|
|
ip = rr.A
|
|
case *dns.AAAA:
|
|
ip = rr.AAAA
|
|
}
|
|
if ttl == 0 {
|
|
ttl = 600
|
|
}
|
|
if len(ip) > 0 {
|
|
ips = append(ips, IPRecord{
|
|
IP: ip,
|
|
Expire: now.Add(time.Second * time.Duration(ttl)),
|
|
})
|
|
}
|
|
}
|
|
|
|
if len(domain) > 0 && len(ips) > 0 {
|
|
s.updateIP(domain, ips)
|
|
}
|
|
}
|
|
|
|
func (s *ClassicNameServer) updateIP(domain string, ips []IPRecord) {
|
|
s.Lock()
|
|
|
|
newError("updating IP records for domain:", domain).AtDebug().WriteToLog()
|
|
now := time.Now()
|
|
eips := s.ips[domain]
|
|
for _, ip := range eips {
|
|
if ip.Expire.After(now) {
|
|
ips = append(ips, ip)
|
|
}
|
|
}
|
|
s.ips[domain] = ips
|
|
s.pub.Publish(domain, nil)
|
|
|
|
s.Unlock()
|
|
common.Must(s.cleanup.Start())
|
|
}
|
|
|
|
func (s *ClassicNameServer) getMsgOptions() *dns.OPT {
|
|
if len(s.clientIP) == 0 {
|
|
return nil
|
|
}
|
|
|
|
o := new(dns.OPT)
|
|
o.Hdr.Name = "."
|
|
o.Hdr.Rrtype = dns.TypeOPT
|
|
o.SetUDPSize(1350)
|
|
|
|
e := new(dns.EDNS0_SUBNET)
|
|
e.Code = dns.EDNS0SUBNET
|
|
if len(s.clientIP) == 4 {
|
|
e.Family = 1 // 1 for IPv4 source address, 2 for IPv6
|
|
e.SourceNetmask = 24 // 32 for IPV4, 128 for IPv6
|
|
} else {
|
|
e.Family = 2
|
|
e.SourceNetmask = 96
|
|
}
|
|
|
|
e.SourceScope = 0
|
|
e.Address = s.clientIP
|
|
o.Option = append(o.Option, e)
|
|
|
|
return o
|
|
}
|
|
|
|
func (s *ClassicNameServer) addPendingRequest(domain string) uint16 {
|
|
id := uint16(atomic.AddUint32(&s.reqID, 1))
|
|
s.Lock()
|
|
defer s.Unlock()
|
|
|
|
s.requests[id] = pendingRequest{
|
|
domain: domain,
|
|
expire: time.Now().Add(time.Second * 8),
|
|
}
|
|
|
|
return id
|
|
}
|
|
|
|
func (s *ClassicNameServer) buildMsgs(domain string) []*dns.Msg {
|
|
allowMulti := multiQuestionDNS[s.address.Address]
|
|
|
|
qA := dns.Question{
|
|
Name: domain,
|
|
Qtype: dns.TypeA,
|
|
Qclass: dns.ClassINET,
|
|
}
|
|
|
|
qAAAA := dns.Question{
|
|
Name: domain,
|
|
Qtype: dns.TypeAAAA,
|
|
Qclass: dns.ClassINET,
|
|
}
|
|
|
|
var msgs []*dns.Msg
|
|
|
|
{
|
|
msg := new(dns.Msg)
|
|
msg.Id = s.addPendingRequest(domain)
|
|
msg.RecursionDesired = true
|
|
msg.Question = []dns.Question{qA}
|
|
if allowMulti {
|
|
msg.Question = append(msg.Question, qAAAA)
|
|
}
|
|
if opt := s.getMsgOptions(); opt != nil {
|
|
msg.Extra = append(msg.Extra, opt)
|
|
}
|
|
msgs = append(msgs, msg)
|
|
}
|
|
|
|
if !allowMulti {
|
|
msg := new(dns.Msg)
|
|
msg.Id = s.addPendingRequest(domain)
|
|
msg.RecursionDesired = true
|
|
msg.Question = []dns.Question{qAAAA}
|
|
if opt := s.getMsgOptions(); opt != nil {
|
|
msg.Extra = append(msg.Extra, opt)
|
|
}
|
|
msgs = append(msgs, msg)
|
|
}
|
|
|
|
return msgs
|
|
}
|
|
|
|
func msgToBuffer(msg *dns.Msg) (*buf.Buffer, error) {
|
|
buffer := buf.New()
|
|
rawBytes := buffer.Extend(buf.Size)
|
|
packed, err := msg.PackBuffer(rawBytes)
|
|
if err != nil {
|
|
buffer.Release()
|
|
return nil, err
|
|
}
|
|
buffer.Resize(0, int32(len(packed)))
|
|
return buffer, nil
|
|
}
|
|
|
|
func (s *ClassicNameServer) sendQuery(ctx context.Context, domain string) {
|
|
newError("querying DNS for: ", domain).AtDebug().WriteToLog(session.ExportIDToError(ctx))
|
|
|
|
msgs := s.buildMsgs(domain)
|
|
|
|
for _, msg := range msgs {
|
|
b, err := msgToBuffer(msg)
|
|
common.Must(err)
|
|
s.udpServer.Dispatch(context.Background(), s.address, b)
|
|
}
|
|
}
|
|
|
|
func (s *ClassicNameServer) findIPsForDomain(domain string) []net.IP {
|
|
s.RLock()
|
|
records, found := s.ips[domain]
|
|
s.RUnlock()
|
|
|
|
if found && len(records) > 0 {
|
|
var ips []net.IP
|
|
now := time.Now()
|
|
for _, rec := range records {
|
|
if rec.Expire.After(now) {
|
|
ips = append(ips, rec.IP)
|
|
}
|
|
}
|
|
return ips
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (s *ClassicNameServer) QueryIP(ctx context.Context, domain string) ([]net.IP, error) {
|
|
fqdn := dns.Fqdn(domain)
|
|
|
|
ips := s.findIPsForDomain(fqdn)
|
|
if len(ips) > 0 {
|
|
return ips, nil
|
|
}
|
|
|
|
sub := s.pub.Subscribe(fqdn)
|
|
defer sub.Close()
|
|
|
|
s.sendQuery(ctx, fqdn)
|
|
|
|
for {
|
|
ips := s.findIPsForDomain(fqdn)
|
|
if len(ips) > 0 {
|
|
return ips, nil
|
|
}
|
|
|
|
select {
|
|
case <-ctx.Done():
|
|
return nil, ctx.Err()
|
|
case <-sub.Wait():
|
|
}
|
|
}
|
|
}
|