feat: add plugin

README.md

@@ -19,3 +19,14 @@ tls.Client(terasu.NewConn(conn), &tls.Config{
     ServerName: host,
 }).Handshake()
 ```
+
+## Custom Plugin (Linux Only)
+
+Custom plugin code is located in the `ext/custom` directory. You can write and build your own plugin.
+
+1. Write your plugin code in the `ext/custom` directory
+2. Build the plugin:
+
+```bash
+GOOS=linux go build -o terasu.plugin.so -buildmode=plugin -ldflags="-s -w" -trimpath ./ext/custom
+```

cmd/main.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"strings"
 
+	_ "github.com/fumiama/terasu/ext"
 	"github.com/fumiama/terasu/http2"
 	"github.com/sirupsen/logrus"
 )

conn_test.go

@@ -5,17 +5,16 @@ import (
 	"io"
 	"net"
 	"net/http"
-	"net/netip"
 	"testing"
+
+	"github.com/fumiama/terasu/dialer"
 )
 
 func TestHTTPDialDifferentFragLen(t *testing.T) {
 	cli := http.Client{
 		Transport: &http.Transport{
 			DialTLS: func(network, addr string) (net.Conn, error) {
-				conn, err := net.DialTCP("tcp", nil, net.TCPAddrFromAddrPort(
-					netip.MustParseAddrPort("52.222.136.117:443"),
-				))
+				conn, err := dialer.DefaultDialer.Dial("tcp", "3.164.110.114:443")
 				if err != nil {
 					return nil, err
 				}
@@ -57,9 +56,7 @@ func TestHTTPDialTLS13(t *testing.T) {
 	cli := http.Client{
 		Transport: &http.Transport{
 			DialTLS: func(network, addr string) (net.Conn, error) {
-				conn, err := net.DialTCP("tcp", nil, net.TCPAddrFromAddrPort(
-					netip.MustParseAddrPort("52.222.136.117:443"),
-				))
+				conn, err := dialer.DefaultDialer.Dial("tcp", "3.164.110.114:443")
 				if err != nil {
 					return nil, err
 				}
@@ -97,9 +94,7 @@ func TestHTTPDialTLS12(t *testing.T) {
 	cli := http.Client{
 		Transport: &http.Transport{
 			DialTLS: func(network, addr string) (net.Conn, error) {
-				conn, err := net.DialTCP("tcp", nil, net.TCPAddrFromAddrPort(
-					netip.MustParseAddrPort("52.222.136.117:443"),
-				))
+				conn, err := dialer.DefaultDialer.Dial("tcp", "3.164.110.114:443")
 				if err != nil {
 					return nil, err
 				}

dialer/dialer.go

@@ -0,0 +1,22 @@
+package dialer
+
+import (
+	"net"
+	"syscall"
+	"time"
+)
+
+// DefaultDialer is the default dialer used for establishing TCP connections
+var DefaultDialer = net.Dialer{
+	Timeout: 4 * time.Second,
+}
+
+// SetDefaultTimeout sets the default timeout for all HTTP2 client connections
+func SetDefaultTimeout(t time.Duration) {
+	DefaultDialer.Timeout = t
+}
+
+// SetDefaultControl sets control of the default dailer
+func SetDefaultControl(c func(network string, address string, c syscall.RawConn) error) {
+	DefaultDialer.Control = c
+}

dns/dns.go

@@ -13,6 +13,8 @@ import (
 	"time"
 
 	"github.com/fumiama/terasu"
+	"github.com/fumiama/terasu/dialer"
+	"github.com/fumiama/terasu/doh"
 	"github.com/fumiama/terasu/ip"
 	"github.com/sirupsen/logrus"
 )
@@ -24,15 +26,6 @@ var (
 	ErrSuccess = errors.New("success")
 )
 
-var dnsDialer = net.Dialer{
-	Timeout: time.Second * 4,
-}
-
-// SetTimeout ...
-func SetTimeout(t time.Duration) {
-	dnsDialer.Timeout = t
-}
-
 type dnsstat struct {
 	addr string
 	en   bool
@@ -173,9 +166,9 @@ func (ds *List) lookupHostDoH(ctx context.Context, host string) (hosts []string,
 			if !addr.enabled() || !addr.ishttps() { // disabled or is not DoH
 				continue
 			}
-			jr, err := lookupdoh(ctx, addr.addr, host)
+			jr, err := doh.LookupDoH(ctx, addr.addr, host)
 			if err == nil {
-				hosts = jr.hosts()
+				hosts = jr.Hosts()
 				if len(hosts) > 0 {
 					// this is a successful server, keep it
 					addr.keepit()
@@ -203,11 +196,11 @@ func (ds *List) lookupHostDoH(ctx context.Context, host string) (hosts []string,
 }
 
 // DialContext ...
-func (ds *List) DialContext(ctx context.Context, dialer *net.Dialer) (tlsConn *tls.Conn, err error) {
+func (ds *List) DialContext(ctx context.Context, d *net.Dialer) (tlsConn *tls.Conn, err error) {
 	err = ErrNoDNSAvailable
 
-	if dialer == nil {
-		dialer = &dnsDialer
+	if d == nil {
+		d = &dialer.DefaultDialer
 	}
 
 	ds.RLock()
@@ -220,16 +213,16 @@ func (ds *List) DialContext(ctx context.Context, dialer *net.Dialer) (tlsConn *t
 				continue
 			}
 			logrus.Debugln("[terasu.dns] -> dial", host, addr)
-			if dialer.Timeout != 0 {
+			if d.Timeout != 0 {
 				var cancel context.CancelFunc
-				ctx, cancel = context.WithTimeout(context.Background(), dialer.Timeout)
+				ctx, cancel = context.WithTimeout(context.Background(), d.Timeout)
 				defer cancel()
-			} else if !dialer.Deadline.IsZero() {
+			} else if !d.Deadline.IsZero() {
 				var cancel context.CancelFunc
-				ctx, cancel = context.WithDeadline(context.Background(), dialer.Deadline)
+				ctx, cancel = context.WithDeadline(context.Background(), d.Deadline)
 				defer cancel()
 			}
-			conn, err = dialer.DialContext(ctx, "tcp", addr.addr)
+			conn, err = d.DialContext(ctx, "tcp", addr.addr)
 			if err != nil {
 				logrus.Debugln("[terasu.dns] -- dial tcp", host, addr, "err:", err)
 				if !errors.Is(err, context.Canceled) &&
@@ -247,13 +240,13 @@ func (ds *List) DialContext(ctx context.Context, dialer *net.Dialer) (tlsConn *t
 				NextProtos: []string{"dns"},
 			})
 			// re-init ctx due to deadline settings in tcp dial
-			if dialer.Timeout != 0 {
+			if d.Timeout != 0 {
 				var cancel context.CancelFunc
-				ctx, cancel = context.WithTimeout(context.Background(), dialer.Timeout)
+				ctx, cancel = context.WithTimeout(context.Background(), d.Timeout)
 				defer cancel()
-			} else if !dialer.Deadline.IsZero() {
+			} else if !d.Deadline.IsZero() {
 				var cancel context.CancelFunc
-				ctx, cancel = context.WithDeadline(context.Background(), dialer.Deadline)
+				ctx, cancel = context.WithDeadline(context.Background(), d.Deadline)
 				defer cancel()
 			}
 			err = tlsConn.HandshakeContext(ctx)

dns/dns_test.go

@@ -4,11 +4,11 @@ import (
 	"context"
 	"crypto/tls"
 	"fmt"
-	"net"
 	"testing"
 	"time"
 
 	"github.com/fumiama/terasu"
+	"github.com/fumiama/terasu/dialer"
 	"github.com/fumiama/terasu/ip"
 )
 
@@ -110,7 +110,7 @@ func (ds *List) test() {
 				continue
 			}
 			fmt.Println("dial:", host, addr.addr)
-			conn, err := net.Dial("tcp", addr.addr)
+			conn, err := dialer.DefaultDialer.Dial("tcp", addr.addr)
 			if err != nil {
 				continue
 			}

dns/tls.go

@@ -0,0 +1,19 @@
+package dns
+
+import (
+	"context"
+	"crypto/tls"
+	"net"
+
+	mtls "github.com/fumiama/terasu/tls"
+)
+
+// DialTLSContext fills http.Transport method with terasu and DNS
+func DialTLSContext(ctx context.Context, network, addr string) (net.Conn, error) {
+	return DialTLSContextWithConfig(ctx, network, addr, nil)
+}
+
+// DialTLSContextWithConfig fills http2.Transport method with terasu and DNS
+func DialTLSContextWithConfig(ctx context.Context, network, addr string, cfg *tls.Config) (net.Conn, error) {
+	return mtls.DialTLSContextCL(ctx, network, addr, cfg, nil)
+}

doh/doh.go

@@ -1,11 +1,9 @@
-package dns
+package doh
 
 import (
 	"context"
-	"crypto/tls"
 	"encoding/json"
 	"errors"
-	"net"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -13,26 +11,22 @@ import (
 
 	"golang.org/x/net/http2"
 
-	"github.com/fumiama/terasu"
 	"github.com/fumiama/terasu/ip"
+	"github.com/fumiama/terasu/tls"
 )
 
-var (
-	// ErrEmptyHostAddress ...
-	ErrEmptyHostAddress = errors.New("empty host addr")
-)
-
-type recordType uint16
+// RecordType ...
+type RecordType uint16
 
 const (
-	recordTypeNone recordType = 0
-	recordTypeA    recordType = 1
-	recordTypeAAAA recordType = 28
+	RecordTypeNone RecordType = 0  // RecordTypeNone ...
+	RecordTypeA    RecordType = 1  // RecordTypeA IPv4
+	RecordTypeAAAA RecordType = 28 // RecordTypeAAAA IPv6
 )
 
-// dohjsonresponse represents the JSON response structure for DNS over HTTPS (DoH) queries.
+// Response represents the JSON response structure for DNS over HTTPS (DoH) queries.
 // It contains DNS query results and metadata about the response.
-type dohjsonresponse struct {
+type Response struct {
 	// Status indicates the DNS query status code (0 = NOERROR, etc.)
 	Status uint32
 	// TC indicates whether the response was truncated (true if truncated)
@@ -50,14 +44,14 @@ type dohjsonresponse struct {
 		// Name is the domain name being queried
 		Name string `json:"name"`
 		// Type is the DNS record type being requested (A, AAAA, etc.)
-		Type recordType `json:"type"`
+		Type RecordType `json:"type"`
 	}
 	// Answer contains the DNS response answer section with resource records
 	Answer []struct {
 		// Name is the domain name for this resource record
 		Name string `json:"name"`
 		// Type is the DNS record type (A, AAAA, etc.)
-		Type recordType `json:"type"`
+		Type RecordType `json:"type"`
 		// TTL is the time-to-live value for this resource record in seconds
 		TTL uint16
 		// Data is the textual representation of the resource record data
@@ -69,13 +63,13 @@ type dohjsonresponse struct {
 	Comment string
 }
 
-func (jr *dohjsonresponse) hosts() []string {
+func (jr *Response) Hosts() []string {
 	if len(jr.Answer) == 0 {
 		return nil
 	}
 	hosts := make([]string, 0, len(jr.Answer))
 	for _, ans := range jr.Answer {
-		if ans.Type == recordTypeA || ans.Type == recordTypeAAAA {
+		if ans.Type == RecordTypeA || ans.Type == RecordTypeAAAA {
 			hosts = append(hosts, ans.Data)
 		}
 	}
@@ -84,70 +78,29 @@ func (jr *dohjsonresponse) hosts() []string {
 
 var trsHTTP2ClientWithSystemDNS = http.Client{
 	Transport: &http2.Transport{
-		DialTLSContext: func(ctx context.Context, network, addr string, cfg *tls.Config) (net.Conn, error) {
-			host, port, err := net.SplitHostPort(addr)
-			if err != nil {
-				return nil, err
-			}
-			addrs := lookupTable.Get(host)
-			if len(addrs) == 0 {
-				addrs, err = net.DefaultResolver.LookupHost(ctx, host)
-				if err != nil {
-					return nil, err
-				}
-				lookupTable.Set(host, addrs)
-			}
-			if len(addr) == 0 {
-				return nil, ErrEmptyHostAddress
-			}
-			var conn net.Conn
-			var tlsConn *tls.Conn
-			for _, a := range addrs {
-				conn, err = dnsDialer.DialContext(ctx, network, net.JoinHostPort(a, port))
-				if err != nil {
-					continue
-				}
-				tlsConn = tls.Client(terasu.NewConn(conn), cfg)
-				err = tlsConn.HandshakeContext(ctx)
-				if err == nil {
-					break
-				}
-				_ = tlsConn.Close()
-				tlsConn = nil
-				conn, err = dnsDialer.DialContext(ctx, network, net.JoinHostPort(a, port))
-				if err != nil {
-					continue
-				}
-				tlsConn = tls.Client(terasu.NewConn(conn), cfg)
-				err = tlsConn.HandshakeContext(ctx)
-				if err == nil {
-					break
-				}
-				_ = tlsConn.Close()
-				tlsConn = nil
-			}
-			return tlsConn, err
-		},
+		DialTLSContext: tls.DialTLSContextWithConfigAndSystemResolver,
 	},
 }
 
-func lookupdoh(ctx context.Context, server, u string) (jr dohjsonresponse, err error) {
-	jr, err = lookupdohwithtype(ctx, server, u, preferreddohtype())
+// LookupDoH lookup uname's ip from server
+func LookupDoH(ctx context.Context, server, name string) (jr Response, err error) {
+	jr, err = LookupDoHWithType(ctx, server, name, prefertyp())
 	if err == nil {
 		return
 	}
 	if ip.IsIPv6Available {
-		jr, err = lookupdohwithtype(ctx, server, u, recordTypeA)
+		jr, err = LookupDoHWithType(ctx, server, name, RecordTypeA)
 	}
 	return
 }
 
-func lookupdohwithtype(ctx context.Context, server, u string, typ recordType) (jr dohjsonresponse, err error) {
+// LookupDoHWithType ...
+func LookupDoHWithType(ctx context.Context, server, name string, typ RecordType) (jr Response, err error) {
 	sb := strings.Builder{}
 	sb.WriteString(server)
 	sb.WriteString("?name=")
-	sb.WriteString(url.QueryEscape(u))
-	if typ != recordTypeNone {
+	sb.WriteString(url.QueryEscape(name))
+	if typ != RecordTypeNone {
 		sb.WriteString("&type=")
 		sb.WriteString(strconv.Itoa(int(typ)))
 	}
@@ -171,9 +124,9 @@ func lookupdohwithtype(ctx context.Context, server, u string, typ recordType) (j
 	return
 }
 
-func preferreddohtype() recordType {
+func prefertyp() RecordType {
 	if ip.IsIPv6Available {
-		return recordTypeAAAA
+		return RecordTypeAAAA
 	}
-	return recordTypeA
+	return RecordTypeA
 }

ext/custom/.gitignore

@@ -0,0 +1,2 @@
+*
+!.gitignore

ext/init.go

@@ -0,0 +1,24 @@
+package ext
+
+import (
+	"os"
+	"plugin"
+
+	"github.com/sirupsen/logrus"
+)
+
+const (
+	TRSPluginFile = "./terasu.plugin.so"
+)
+
+func init() {
+	if _, err := os.Stat(TRSPluginFile); err != nil {
+		return
+	}
+	_, err := plugin.Open(TRSPluginFile)
+	if err != nil {
+		logrus.Warnln("[terasu.plugin] load", TRSPluginFile, "err:", err)
+		logrus.Warnln("[terasu.plugin] hint: ensure the main binary and plugin are built with identical flags (e.g. both use -trimpath -ldflags=\"-s -w\"), and avoid using 'go run'")
+		return
+	}
+}

http/http.go

@@ -2,106 +2,19 @@
 package http
 
 import (
-	"context"
-	"crypto/tls"
-	"errors"
 	"io"
-	"net"
 	"net/http"
 	"net/url"
 	"time"
 
-	"github.com/fumiama/terasu"
 	"github.com/fumiama/terasu/dns"
 )
 
-var (
-	// ErrNoTLSConnection is returned when a TLS connection cannot be established.
-	ErrNoTLSConnection = errors.New("no tls connection")
-	// ErrEmptyHostAddress is returned when the host address is empty.
-	ErrEmptyHostAddress = errors.New("empty host addr")
-)
-
-// defaultDialer is the default dialer used for connecting to hosts.
-var defaultDialer = net.Dialer{
-	Timeout: 10 * time.Second,
-}
-
-// SetDefaultClientTimeout sets the default timeout for the client's dialer.
-func SetDefaultClientTimeout(t time.Duration) {
-	defaultDialer.Timeout = t
-}
-
 // DefaultClient is the default HTTP client with custom transport settings, including DNS resolution and TLS handling.
 var DefaultClient = http.Client{
 	Transport: &http.Transport{
-		Proxy: http.ProxyFromEnvironment,
-		DialTLSContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
-			host, port, err := net.SplitHostPort(addr)
-			if err != nil {
-				return nil, err
-			}
-			addrs, err := dns.LookupHost(ctx, host)
-			if err != nil {
-				return nil, err
-			}
-			if len(addrs) == 0 {
-				return nil, ErrEmptyHostAddress
-			}
-			var conn net.Conn
-			var tlsConn *tls.Conn
-			for _, a := range addrs {
-				// Apply timeout if set, otherwise use deadline
-				if defaultDialer.Timeout != 0 {
-					var cancel context.CancelFunc
-					ctx, cancel = context.WithTimeout(context.Background(), defaultDialer.Timeout)
-					defer cancel()
-				} else if !defaultDialer.Deadline.IsZero() {
-					var cancel context.CancelFunc
-					ctx, cancel = context.WithDeadline(context.Background(), defaultDialer.Deadline)
-					defer cancel()
-				}
-				conn, err = defaultDialer.DialContext(ctx, network, net.JoinHostPort(a, port))
-				if err != nil {
-					continue
-				}
-				tlsConn = tls.Client(terasu.NewConn(conn), &tls.Config{
-					ServerName: host,
-					MinVersion: tls.VersionTLS12,
-				})
-				// Re-initialize context due to potential deadline changes from TCP dial
-				if defaultDialer.Timeout != 0 {
-					var cancel context.CancelFunc
-					ctx, cancel = context.WithTimeout(context.Background(), defaultDialer.Timeout)
-					defer cancel()
-				} else if !defaultDialer.Deadline.IsZero() {
-					var cancel context.CancelFunc
-					ctx, cancel = context.WithDeadline(context.Background(), defaultDialer.Deadline)
-					defer cancel()
-				}
-				err = tlsConn.HandshakeContext(ctx)
-				if err == nil {
-					break
-				}
-				_ = tlsConn.Close()
-				tlsConn = nil
-				conn, err = defaultDialer.DialContext(ctx, network, net.JoinHostPort(a, port))
-				if err != nil {
-					continue
-				}
-				tlsConn = tls.Client(terasu.NewConn(conn), &tls.Config{
-					ServerName: host,
-					MinVersion: tls.VersionTLS12,
-				})
-				err = tlsConn.HandshakeContext(ctx)
-				if err == nil {
-					break
-				}
-				_ = tlsConn.Close()
-				tlsConn = nil
-			}
-			return tlsConn, err
-		},
+		Proxy:                 http.ProxyFromEnvironment,
+		DialTLSContext:        dns.DialTLSContext,
 		ForceAttemptHTTP2:     true,
 		MaxIdleConns:          100,
 		IdleConnTimeout:       90 * time.Second,

http2/http.go

@@ -2,96 +2,18 @@
 package http2
 
 import (
-	"context"
-	"crypto/tls"
-	"errors"
 	"io"
-	"net"
 	"net/http"
 	"net/url"
-	"time"
 
-	"golang.org/x/net/http2"
-
-	"github.com/fumiama/terasu"
 	"github.com/fumiama/terasu/dns"
+	"golang.org/x/net/http2"
 )
 
-// ErrEmptyHostAddress is returned when DNS lookup for a host returns no addresses
-var ErrEmptyHostAddress = errors.New("empty host addr")
-
-// defaultDialer is the default dialer used for establishing TCP connections
-var defaultDialer = net.Dialer{
-	Timeout: 10 * time.Second,
-}
-
-// SetDefaultClientTimeout sets the default timeout for all HTTP2 client connections
-func SetDefaultClientTimeout(t time.Duration) {
-	defaultDialer.Timeout = t
-}
-
 // DefaultClient is the default HTTP2 client that supports HTTP/2 and DNS resolution
 var DefaultClient = http.Client{
 	Transport: &http2.Transport{
-		DialTLSContext: func(ctx context.Context, network, addr string, cfg *tls.Config) (net.Conn, error) {
-			host, port, err := net.SplitHostPort(addr)
-			if err != nil {
-				return nil, err
-			}
-			addrs, err := dns.LookupHost(ctx, host)
-			if err != nil {
-				return nil, err
-			}
-			if len(addrs) == 0 {
-				return nil, ErrEmptyHostAddress
-			}
-			var conn net.Conn
-			var tlsConn *tls.Conn
-			for _, a := range addrs {
-				if defaultDialer.Timeout != 0 {
-					var cancel context.CancelFunc
-					ctx, cancel = context.WithTimeout(context.Background(), defaultDialer.Timeout)
-					defer cancel()
-				} else if !defaultDialer.Deadline.IsZero() {
-					var cancel context.CancelFunc
-					ctx, cancel = context.WithDeadline(context.Background(), defaultDialer.Deadline)
-					defer cancel()
-				}
-				conn, err = defaultDialer.DialContext(ctx, network, net.JoinHostPort(a, port))
-				if err != nil {
-					continue
-				}
-				tlsConn = tls.Client(terasu.NewConn(conn), cfg)
-				// re-init ctx due to deadline settings in tcp dial
-				if defaultDialer.Timeout != 0 {
-					var cancel context.CancelFunc
-					ctx, cancel = context.WithTimeout(context.Background(), defaultDialer.Timeout)
-					defer cancel()
-				} else if !defaultDialer.Deadline.IsZero() {
-					var cancel context.CancelFunc
-					ctx, cancel = context.WithDeadline(context.Background(), defaultDialer.Deadline)
-					defer cancel()
-				}
-				err = tlsConn.HandshakeContext(ctx)
-				if err == nil {
-					break
-				}
-				_ = tlsConn.Close()
-				tlsConn = nil
-				conn, err = defaultDialer.DialContext(ctx, network, net.JoinHostPort(a, port))
-				if err != nil {
-					continue
-				}
-				tlsConn = tls.Client(terasu.NewConn(conn), cfg)
-				err = tlsConn.HandshakeContext(ctx)
-				if err == nil {
-					break
-				}
-				_ = tlsConn.Close()
-				tlsConn = nil
-			}
-			return tlsConn, err
-		},
+		DialTLSContext: dns.DialTLSContextWithConfig,
 	},
 }
 

http3/http.go

@@ -13,9 +13,9 @@ import (
 	"net/http"
 	"net/netip"
 	"net/url"
-	"time"
 
 	base14 "github.com/fumiama/go-base16384"
+	"github.com/fumiama/terasu/dialer"
 	"github.com/fumiama/terasu/dns"
 	"github.com/quic-go/quic-go"
 	"github.com/quic-go/quic-go/http3"
@@ -24,16 +24,6 @@ import (
 // ErrEmptyHostAddress is returned when DNS lookup for a host returns no addresses
 var ErrEmptyHostAddress = errors.New("empty host addr")
 
-// defaultDialer is the default dialer used for establishing TCP connections
-var defaultDialer = net.Dialer{
-	Timeout: 10 * time.Second,
-}
-
-// SetDefaultClientTimeout sets the default timeout for all HTTP2 client connections
-func SetDefaultClientTimeout(t time.Duration) {
-	defaultDialer.Timeout = t
-}
-
 // DefaultClient is the default HTTP2 client that supports HTTP/2 and DNS resolution
 var DefaultClient = http.Client{
 	Transport: &http3.Transport{
@@ -52,13 +42,13 @@ var DefaultClient = http.Client{
 			var conn net.Conn
 			var qConn quic.EarlyConnection
 			for _, a := range addrs {
-				if defaultDialer.Timeout != 0 {
+				if dialer.DefaultDialer.Timeout != 0 {
 					var cancel context.CancelFunc
-					ctx, cancel = context.WithTimeout(context.Background(), defaultDialer.Timeout)
+					ctx, cancel = context.WithTimeout(context.Background(), dialer.DefaultDialer.Timeout)
 					defer cancel()
-				} else if !defaultDialer.Deadline.IsZero() {
+				} else if !dialer.DefaultDialer.Deadline.IsZero() {
 					var cancel context.CancelFunc
-					ctx, cancel = context.WithDeadline(context.Background(), defaultDialer.Deadline)
+					ctx, cancel = context.WithDeadline(context.Background(), dialer.DefaultDialer.Deadline)
 					defer cancel()
 				}
 				conn, err = net.ListenUDP("udp", nil)
@@ -76,13 +66,13 @@ var DefaultClient = http.Client{
 				_ = e.Close()
 				_, _ = ucon.WriteToUDP(w.Bytes(), raddr)
 				// re-init ctx due to deadline settings in tcp dial
-				if defaultDialer.Timeout != 0 {
+				if dialer.DefaultDialer.Timeout != 0 {
 					var cancel context.CancelFunc
-					ctx, cancel = context.WithTimeout(context.Background(), defaultDialer.Timeout)
+					ctx, cancel = context.WithTimeout(context.Background(), dialer.DefaultDialer.Timeout)
 					defer cancel()
-				} else if !defaultDialer.Deadline.IsZero() {
+				} else if !dialer.DefaultDialer.Deadline.IsZero() {
 					var cancel context.CancelFunc
-					ctx, cancel = context.WithDeadline(context.Background(), defaultDialer.Deadline)
+					ctx, cancel = context.WithDeadline(context.Background(), dialer.DefaultDialer.Deadline)
 					defer cancel()
 				}
 				qConn, err = quic.DialEarly(ctx, ucon, raddr, tlsCfg, cfg)

tls/dial.go

@@ -0,0 +1,94 @@
+package tls
+
+import (
+	"context"
+	"crypto/tls"
+	"errors"
+	"net"
+
+	"github.com/fumiama/terasu"
+	"github.com/fumiama/terasu/dialer"
+)
+
+// ErrEmptyHostAddress is returned when DNS lookup for a host returns no addresses
+var ErrEmptyHostAddress = errors.New("empty host addr")
+
+// DialTLSContextWithConfigAndSystemResolver fills http2.Transport method with terasu and system DNS
+func DialTLSContextWithConfigAndSystemResolver(ctx context.Context, network, addr string, cfg *tls.Config) (net.Conn, error) {
+	return DialTLSContextCL(ctx, network, addr, cfg, nil)
+}
+
+// DialTLSContextCL fills http2.Transport method with terasu
+func DialTLSContextCL(
+	ctx context.Context, network, addr string,
+	cfg *tls.Config, lookup func(ctx context.Context, host string,
+	) (addrs []string, err error)) (net.Conn, error) {
+	host, port, err := net.SplitHostPort(addr)
+	if err != nil {
+		return nil, err
+	}
+	var addrs []string
+	if lookup != nil {
+		addrs, err = lookup(ctx, host)
+	} else {
+		addrs, err = net.DefaultResolver.LookupHost(ctx, host)
+	}
+	if err != nil {
+		return nil, err
+	}
+	if len(addrs) == 0 {
+		return nil, ErrEmptyHostAddress
+	}
+	if cfg == nil {
+		cfg = &tls.Config{
+			ServerName: host,
+			MinVersion: tls.VersionTLS12,
+		}
+	}
+	var conn net.Conn
+	var tlsConn *tls.Conn
+	for _, a := range addrs {
+		if dialer.DefaultDialer.Timeout != 0 {
+			var cancel context.CancelFunc
+			ctx, cancel = context.WithTimeout(context.Background(), dialer.DefaultDialer.Timeout)
+			defer cancel()
+		} else if !dialer.DefaultDialer.Deadline.IsZero() {
+			var cancel context.CancelFunc
+			ctx, cancel = context.WithDeadline(context.Background(), dialer.DefaultDialer.Deadline)
+			defer cancel()
+		}
+		conn, err = dialer.DefaultDialer.DialContext(ctx, network, net.JoinHostPort(a, port))
+		if err != nil {
+			continue
+		}
+		tlsConn = tls.Client(terasu.NewConn(conn), cfg)
+		// re-init ctx due to deadline settings in tcp dial
+		if dialer.DefaultDialer.Timeout != 0 {
+			var cancel context.CancelFunc
+			ctx, cancel = context.WithTimeout(context.Background(), dialer.DefaultDialer.Timeout)
+			defer cancel()
+		} else if !dialer.DefaultDialer.Deadline.IsZero() {
+			var cancel context.CancelFunc
+			ctx, cancel = context.WithDeadline(context.Background(), dialer.DefaultDialer.Deadline)
+			defer cancel()
+		}
+		err = tlsConn.HandshakeContext(ctx)
+		if err == nil {
+			break
+		}
+		_ = tlsConn.Close()
+		tlsConn = nil
+		conn, err = dialer.DefaultDialer.DialContext(ctx, network, net.JoinHostPort(a, port))
+		if err != nil {
+			continue
+		}
+		tlsConn = tls.Client(terasu.NewConn(conn), cfg)
+		err = tlsConn.HandshakeContext(ctx)
+		if err == nil {
+			break
+		}
+		_ = tlsConn.Close()
+		tlsConn = nil
+	}
+	return tlsConn, err
+}