121 lines
2.0 KiB
Go
121 lines
2.0 KiB
Go
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package tunnel
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import (
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"crypto/tls"
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"fmt"
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"net"
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"sync"
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"time"
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"git.xeserv.us/xena/route/lib/tunnel/proto"
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"github.com/cenkalti/backoff"
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)
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// async is a helper function to convert a blocking function to a function
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// returning an error. Useful for plugging function closures into select and co
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func async(fn func() error) <-chan error {
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errChan := make(chan error, 0)
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go func() {
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select {
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case errChan <- fn():
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default:
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}
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close(errChan)
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}()
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return errChan
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}
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type expBackoff struct {
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mu sync.Mutex
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bk *backoff.ExponentialBackOff
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}
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func newForeverBackoff() *expBackoff {
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eb := &expBackoff{
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bk: backoff.NewExponentialBackOff(),
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}
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eb.bk.MaxElapsedTime = 0 // never stops
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return eb
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}
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func (eb *expBackoff) NextBackOff() time.Duration {
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eb.mu.Lock()
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defer eb.mu.Unlock()
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return eb.bk.NextBackOff()
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}
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func (eb *expBackoff) Reset() {
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eb.mu.Lock()
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eb.bk.Reset()
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eb.mu.Unlock()
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}
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type callbacks struct {
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mu sync.Mutex
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name string
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funcs map[string]func() error
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}
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func newCallbacks(name string) *callbacks {
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return &callbacks{
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name: name,
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funcs: make(map[string]func() error),
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}
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}
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func (c *callbacks) add(identifier string, fn func() error) {
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c.mu.Lock()
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c.funcs[identifier] = fn
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c.mu.Unlock()
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}
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func (c *callbacks) pop(identifier string) (func() error, error) {
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c.mu.Lock()
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defer c.mu.Unlock()
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fn, ok := c.funcs[identifier]
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if !ok {
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return nil, nil // nop
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}
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delete(c.funcs, identifier)
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if fn == nil {
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return nil, fmt.Errorf("nil callback set for %q client", identifier)
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}
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return fn, nil
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}
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func (c *callbacks) call(identifier string) error {
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fn, err := c.pop(identifier)
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if err != nil {
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return err
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}
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if fn == nil {
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return nil // nop
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}
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return fn()
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}
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// Returns server control url as a string. Reads scheme and remote address from connection.
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func controlURL(conn net.Conn) string {
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return fmt.Sprint(scheme(conn), "://", conn.RemoteAddr(), proto.ControlPath)
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}
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func scheme(conn net.Conn) (scheme string) {
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switch conn.(type) {
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case *tls.Conn:
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scheme = "https"
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default:
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scheme = "http"
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}
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return
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}
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