229 lines
6.4 KiB
Go
229 lines
6.4 KiB
Go
package zgrab2
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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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// TimeoutConnection wraps an existing net.Conn connection, overriding the Read/Write methods to use the configured timeouts
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type TimeoutConnection struct {
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net.Conn
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ctx context.Context
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Timeout time.Duration
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ReadTimeout time.Duration
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WriteTimeout time.Duration
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explicitReadDeadline bool
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explicitWriteDeadline bool
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explicitDeadline bool
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}
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// TimeoutConnection.Read calls Read() on the underlying connection, using any configured deadlines
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func (c *TimeoutConnection) Read(b []byte) (n int, err error) {
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if err := c.checkContext(); err != nil {
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return 0, err
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}
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if c.explicitReadDeadline || c.explicitDeadline {
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c.explicitReadDeadline = false
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c.explicitDeadline = false
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} else if readTimeout := c.getTimeout(c.ReadTimeout); readTimeout > 0 {
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if err = c.Conn.SetReadDeadline(time.Now().Add(readTimeout)); err != nil {
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return 0, err
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}
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}
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return c.Conn.Read(b)
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}
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// TimeoutConnection.Write calls Write() on the underlying connection, using any configured deadlines.
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func (c *TimeoutConnection) Write(b []byte) (n int, err error) {
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if err := c.checkContext(); err != nil {
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return 0, err
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}
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if c.explicitWriteDeadline || c.explicitDeadline {
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c.explicitWriteDeadline = false
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c.explicitDeadline = false
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} else if writeTimeout := c.getTimeout(c.WriteTimeout); writeTimeout > 0 {
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if err = c.Conn.SetWriteDeadline(time.Now().Add(writeTimeout)); err != nil {
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return 0, err
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}
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}
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return c.Conn.Write(b)
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}
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// SetReadDeadline sets an explicit ReadDeadline that will override the timeout
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// for one read. Use deadline = 0 to clear the deadline.
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func (c *TimeoutConnection) SetReadDeadline(deadline time.Time) error {
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if err := c.checkContext(); err != nil {
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return err
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}
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if !deadline.IsZero() {
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err := c.Conn.SetReadDeadline(deadline)
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if err != nil {
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return err
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}
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}
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c.explicitReadDeadline = !deadline.IsZero()
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return nil
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}
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// SetWriteDeadline sets an explicit WriteDeadline that will override the
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// WriteDeadline for one write. Use deadline = 0 to clear the deadline.
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func (c *TimeoutConnection) SetWriteDeadline(deadline time.Time) error {
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if err := c.checkContext(); err != nil {
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return err
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}
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if !deadline.IsZero() {
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err := c.Conn.SetWriteDeadline(deadline)
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if err != nil {
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return err
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}
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}
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c.explicitWriteDeadline = deadline.IsZero()
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return nil
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}
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// SetDeadline sets a read / write deadline that will override the deadline for
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// a single read/write. Use deadline = 0 to clear the deadline.
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func (c *TimeoutConnection) SetDeadline(deadline time.Time) error {
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if err := c.checkContext(); err != nil {
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return err
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}
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if !deadline.IsZero() {
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err := c.Conn.SetDeadline(deadline)
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if err != nil {
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return err
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}
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}
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c.explicitDeadline = deadline.IsZero()
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return nil
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}
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// GetTimeoutDialer returns a Dialer function that dials with the given timeout
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func GetTimeoutDialer(timeout time.Duration) func(string, string) (net.Conn, error) {
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return func(proto, target string) (net.Conn, error) {
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return DialTimeoutConnection(proto, target, timeout)
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}
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}
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// Close the underlying connection.
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func (c *TimeoutConnection) Close() error {
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return c.Conn.Close()
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}
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// Get the timeout for the given field, falling back to the global timeout.
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func (c *TimeoutConnection) getTimeout(field time.Duration) time.Duration {
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if field == 0 {
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return c.Timeout
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}
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return field
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}
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// Check if the context has been cancelled, and if so, return an error (either the context error, or
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// if the context error is nil, ErrTotalTimeout).
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func (c *TimeoutConnection) checkContext() error {
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if c.ctx == nil {
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return nil
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}
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select {
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case <-c.ctx.Done():
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if err := c.ctx.Err(); err != nil {
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return err
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} else {
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return ErrTotalTimeout
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}
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default:
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return nil
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}
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}
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// DialTimeoutConnection dials the target and returns a net.Conn that uses the configured timeouts for Read/Write operations.
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func DialTimeoutConnection(proto string, target string, timeout time.Duration) (net.Conn, error) {
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var conn net.Conn
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var err error
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if timeout > 0 {
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conn, err = net.DialTimeout(proto, target, timeout)
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} else {
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conn, err = net.Dial(proto, target)
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}
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if err != nil {
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if conn != nil {
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conn.Close()
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}
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return nil, err
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}
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ctx, _ := context.WithTimeout(context.Background(), timeout)
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return &TimeoutConnection{
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Conn: conn,
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Timeout: timeout,
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ReadTimeout: timeout,
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WriteTimeout: timeout,
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ctx: ctx,
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}, nil
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}
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// Dialer provides Dial and DialContext methods to get connections with the given timeout.
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type Dialer struct {
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// Timeout is the maximum time to wait for the entire session, after which any operations on the
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// connection will fail.
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Timeout time.Duration
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// ConnectTimeout is the maximum time to wait for a connection.
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ConnectTimeout time.Duration
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// ReadTimeout is the maximum time to wait for a Read
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ReadTimeout time.Duration
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// WriteTimeout is the maximum time to wait for a Write
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WriteTimeout time.Duration
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// Dialer is an auxiliary dialer used for DialContext (the result gets wrapped in a TimeoutConnection).
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Dialer *net.Dialer
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}
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func (d *Dialer) getTimeout(field time.Duration) time.Duration {
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if field == 0 {
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return d.Timeout
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}
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return field
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}
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// DialContext wraps the connection returned by net.Dialer.DialContext() with a TimeoutConnection.
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func (d *Dialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
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if d.Timeout != 0 {
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ctx, _ = context.WithTimeout(ctx, d.Timeout)
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}
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// ensure that our aux dialer is up-to-date; copied from http/transport.go
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d.Dialer.Timeout = d.getTimeout(d.ConnectTimeout)
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d.Dialer.KeepAlive = d.Timeout
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dialContext, cancelDial := context.WithTimeout(ctx, d.Dialer.Timeout)
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defer cancelDial()
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ret, err := d.Dialer.DialContext(dialContext, network, address)
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if err != nil {
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return nil, err
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}
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return &TimeoutConnection{
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ctx: ctx,
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Conn: ret,
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ReadTimeout: d.ReadTimeout,
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WriteTimeout: d.WriteTimeout,
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Timeout: d.Timeout,
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}, nil
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}
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// Dial returns a connection with the configured timeout.
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func (d *Dialer) Dial(proto string, target string) (net.Conn, error) {
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return DialTimeoutConnection(proto, target, d.Timeout)
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}
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// GetTimeoutConnectionDialer gets a Dialer that dials connections with the given timeout.
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func GetTimeoutConnectionDialer(timeout time.Duration) *Dialer {
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return &Dialer{
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Timeout: timeout,
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Dialer: &net.Dialer{
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Timeout: timeout,
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KeepAlive: timeout,
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DualStack: true,
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},
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}
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}
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