112 lines
3.0 KiB
Go
112 lines
3.0 KiB
Go
package prox5
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import (
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"context"
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"fmt"
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"net"
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"strings"
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"sync/atomic"
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"time"
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"git.tcp.direct/kayos/socks"
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"git.tcp.direct/kayos/prox5/internal/pools"
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)
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// DialContext is a simple stub adapter to implement a net.Dialer.
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func (pe *ProxyEngine) DialContext(ctx context.Context, network, addr string) (net.Conn, error) {
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return pe.MysteryDialer(ctx, network, addr)
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}
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// Dial is a simple stub adapter to implement a net.Dialer.
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func (pe *ProxyEngine) Dial(network, addr string) (net.Conn, error) {
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return pe.MysteryDialer(context.Background(), network, addr)
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}
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// DialTimeout is a simple stub adapter to implement a net.Dialer with a timeout.
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func (pe *ProxyEngine) DialTimeout(network, addr string, timeout time.Duration) (net.Conn, error) {
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ctx, cancel := context.WithDeadline(context.Background(), time.Now().Add(timeout))
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go func() { // this is a goroutine that calls cancel() upon the deadline expiring to avoid context leaks
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<-ctx.Done()
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cancel()
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}()
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return pe.MysteryDialer(ctx, network, addr)
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}
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func (pe *ProxyEngine) addTimeout(socksString string) string {
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tout := pools.CopABuffer.Get().(*strings.Builder)
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tout.WriteString(socksString)
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tout.WriteString("?timeout=")
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tout.WriteString(pe.GetServerTimeoutStr())
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tout.WriteRune('s')
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socksString = tout.String()
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pools.DiscardBuffer(tout)
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return socksString
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}
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func (pe *ProxyEngine) popSockAndLockIt(ctx context.Context) (*Proxy, error) {
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sock := pe.GetAnySOCKS(false)
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socksString := sock.String()
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select {
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case <-ctx.Done():
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return nil, fmt.Errorf("context done: %w", ctx.Err())
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default:
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if atomic.CompareAndSwapUint32(&sock.lock, stateUnlocked, stateLocked) {
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pe.msgGotLock(socksString)
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return sock, nil
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}
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select {
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case pe.Pending <- sock:
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pe.msgCantGetLock(socksString, true)
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return nil, nil
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default:
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pe.msgCantGetLock(socksString, false)
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return nil, nil
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}
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}
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}
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// MysteryDialer is a dialer function that will use a different proxy for every request.
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func (pe *ProxyEngine) MysteryDialer(ctx context.Context, network, addr string) (net.Conn, error) {
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// pull down proxies from channel until we get a proxy good enough for our spoiled asses
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var count = 0
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for {
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max := pe.GetDialerBailout()
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if count > max {
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return nil, fmt.Errorf("giving up after %d tries", max)
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}
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if err := ctx.Err(); err != nil {
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return nil, fmt.Errorf("context error: %w", err)
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}
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var sock *Proxy
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for {
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var err error
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sock, err = pe.popSockAndLockIt(ctx)
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if err != nil {
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return nil, err
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}
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if sock != nil {
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break
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}
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}
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socksString := sock.String()
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var ok bool
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if sock, ok = pe.dispenseMiddleware(sock); !ok {
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atomic.StoreUint32(&sock.lock, stateUnlocked)
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pe.msgFailedMiddleware(socksString)
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continue
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}
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pe.msgTry(socksString)
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atomic.StoreUint32(&sock.lock, stateUnlocked)
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dialSocks := socks.Dial(socksString)
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conn, err := dialSocks(network, addr)
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if err != nil {
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count++
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pe.msgUnableToReach(socksString, addr, err)
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continue
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}
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pe.msgUsingProxy(socksString)
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return conn, nil
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}
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}
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