/
stream_dialer.go
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/
stream_dialer.go
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// Copyright 2024 Jigsaw Operations LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package dns
import (
"context"
"errors"
"fmt"
"net/netip"
"github.com/Jigsaw-Code/outline-sdk/transport"
"golang.org/x/net/dns/dnsmessage"
)
func resolveIP(ctx context.Context, resolver Resolver, rrType dnsmessage.Type, hostname string) ([]netip.Addr, error) {
ips := []netip.Addr{}
q, err := NewQuestion(hostname, rrType)
if err != nil {
return nil, err
}
response, err := resolver.Query(ctx, *q)
if err != nil {
return nil, err
}
if response.RCode != dnsmessage.RCodeSuccess {
return nil, fmt.Errorf("got %v (%d)", response.RCode.String(), response.RCode)
}
for _, answer := range response.Answers {
if answer.Header.Type != rrType {
continue
}
if rr, ok := answer.Body.(*dnsmessage.AResource); ok {
ips = append(ips, netip.AddrFrom4(rr.A))
}
if rr, ok := answer.Body.(*dnsmessage.AAAAResource); ok {
ips = append(ips, netip.AddrFrom16(rr.AAAA))
}
}
return ips, nil
}
// NewStreamDialer creates a [transport.StreamDialer] that uses Happy Eyeballs v2 to establish a connection.
// It uses resolver to map host names to IP addresses, and the given dialer to attempt connections.
func NewStreamDialer(resolver Resolver, dialer transport.StreamDialer) (transport.StreamDialer, error) {
if resolver == nil {
return nil, errors.New("resolver must not be nil")
}
if dialer == nil {
return nil, errors.New("dialer must not be nil")
}
return &transport.HappyEyeballsStreamDialer{
Dialer: dialer,
Resolve: transport.NewParallelHappyEyeballsResolveFunc(
func(ctx context.Context, hostname string) ([]netip.Addr, error) {
return resolveIP(ctx, resolver, dnsmessage.TypeAAAA, hostname)
},
func(ctx context.Context, hostname string) ([]netip.Addr, error) {
return resolveIP(ctx, resolver, dnsmessage.TypeA, hostname)
},
),
}, nil
}