AdGuardHome/internal/dnsforward/dialcontext.go

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package dnsforward
import (
"context"
"fmt"
"net"
"time"
"github.com/AdguardTeam/golibs/errors"
"github.com/AdguardTeam/golibs/log"
)
// DialContext is an [aghnet.DialContextFunc] that uses s to resolve hostnames.
func (s *Server) DialContext(ctx context.Context, network, addr string) (conn net.Conn, err error) {
log.Debug("dnsforward: dialing %q for network %q", addr, network)
host, port, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
dialer := &net.Dialer{
// TODO(a.garipov): Consider making configurable.
Timeout: time.Minute * 5,
}
if net.ParseIP(host) != nil {
return dialer.DialContext(ctx, network, addr)
}
addrs, err := s.Resolve(host)
if err != nil {
return nil, fmt.Errorf("resolving %q: %w", host, err)
}
log.Debug("dnsforward: resolving %q: %v", host, addrs)
if len(addrs) == 0 {
return nil, fmt.Errorf("no addresses for host %q", host)
}
var dialErrs []error
for _, a := range addrs {
addr = net.JoinHostPort(a.String(), port)
conn, err = dialer.DialContext(ctx, network, addr)
if err != nil {
dialErrs = append(dialErrs, err)
continue
}
return conn, err
}
// TODO(a.garipov): Use errors.Join in Go 1.20.
return nil, errors.List(fmt.Sprintf("dialing %q", addr), dialErrs...)
}