87 lines
2.4 KiB
Go
87 lines
2.4 KiB
Go
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package netxlite
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import (
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"context"
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"net"
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"time"
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)
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// Dialer establishes network connections.
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type Dialer interface {
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// DialContext behaves like net.Dialer.DialContext.
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DialContext(ctx context.Context, network, address string) (net.Conn, error)
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}
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// DefaultDialer is the Dialer we use by default.
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var DefaultDialer = &net.Dialer{
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Timeout: 15 * time.Second,
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KeepAlive: 15 * time.Second,
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}
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var _ Dialer = DefaultDialer
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// DialerResolver is a dialer that uses the configured Resolver to resolver a
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// domain name to IP addresses, and the configured Dialer to connect.
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type DialerResolver struct {
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// Dialer is the underlying Dialer.
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Dialer Dialer
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// Resolver is the underlying Resolver.
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Resolver Resolver
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}
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var _ Dialer = &DialerResolver{}
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// DialContext implements Dialer.DialContext.
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func (d *DialerResolver) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
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onlyhost, onlyport, err := net.SplitHostPort(address)
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if err != nil {
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return nil, err
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}
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var addrs []string
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addrs, err = d.lookupHost(ctx, onlyhost)
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if err != nil {
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return nil, err
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}
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// TODO(bassosimone): here we should be using multierror rather
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// than just calling ReduceErrors. We are not ready to do that
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// yet, though. To do that, we need first to modify nettests so
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// that we actually avoid dialing when measuring.
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var errorslist []error
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for _, addr := range addrs {
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target := net.JoinHostPort(addr, onlyport)
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conn, err := d.Dialer.DialContext(ctx, network, target)
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if err == nil {
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return conn, nil
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}
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errorslist = append(errorslist, err)
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}
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return nil, ReduceErrors(errorslist)
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}
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// lookupHost performs a domain name resolution.
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func (d *DialerResolver) lookupHost(ctx context.Context, hostname string) ([]string, error) {
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if net.ParseIP(hostname) != nil {
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return []string{hostname}, nil
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}
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return d.Resolver.LookupHost(ctx, hostname)
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}
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// DialerLogger is a Dialer with logging
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type DialerLogger struct {
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Dialer
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Logger Logger
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}
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var _ Dialer = &DialerLogger{}
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// DialContext implements Dialer.DialContext
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func (d *DialerLogger) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
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d.Logger.Debugf("dial %s/%s...", address, network)
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start := time.Now()
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conn, err := d.Dialer.DialContext(ctx, network, address)
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stop := time.Now()
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d.Logger.Debugf("dial %s/%s... %+v in %s", address, network, err, stop.Sub(start))
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return conn, err
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}
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