47276bdb28
Formatting the code with https://github.com/mvdan/gofumpt Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
98 lines
2.5 KiB
Go
98 lines
2.5 KiB
Go
package main
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import (
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"io"
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"log"
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"net"
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"sync"
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"github.com/ishidawataru/sctp"
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)
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// SCTPProxy is a proxy for SCTP connections. It implements the Proxy interface to
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// handle SCTP traffic forwarding between the frontend and backend addresses.
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type SCTPProxy struct {
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listener *sctp.SCTPListener
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frontendAddr *sctp.SCTPAddr
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backendAddr *sctp.SCTPAddr
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}
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// NewSCTPProxy creates a new SCTPProxy.
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func NewSCTPProxy(frontendAddr, backendAddr *sctp.SCTPAddr) (*SCTPProxy, error) {
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// detect version of hostIP to bind only to correct version
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ipVersion := ipv4
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if frontendAddr.IPAddrs[0].IP.To4() == nil {
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ipVersion = ipv6
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}
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listener, err := sctp.ListenSCTP("sctp"+string(ipVersion), frontendAddr)
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if err != nil {
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return nil, err
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}
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// If the port in frontendAddr was 0 then ListenSCTP will have a picked
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// a port to listen on, hence the call to Addr to get that actual port:
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return &SCTPProxy{
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listener: listener,
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frontendAddr: listener.Addr().(*sctp.SCTPAddr),
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backendAddr: backendAddr,
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}, nil
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}
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func (proxy *SCTPProxy) clientLoop(client *sctp.SCTPConn, quit chan bool) {
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backend, err := sctp.DialSCTP("sctp", nil, proxy.backendAddr)
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if err != nil {
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log.Printf("Can't forward traffic to backend sctp/%v: %s\n", proxy.backendAddr, err)
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client.Close()
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return
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}
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clientC := sctp.NewSCTPSndRcvInfoWrappedConn(client)
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backendC := sctp.NewSCTPSndRcvInfoWrappedConn(backend)
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var wg sync.WaitGroup
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broker := func(to, from net.Conn) {
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io.Copy(to, from)
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from.Close()
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to.Close()
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wg.Done()
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}
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wg.Add(2)
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go broker(clientC, backendC)
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go broker(backendC, clientC)
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finish := make(chan struct{})
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go func() {
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wg.Wait()
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close(finish)
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}()
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select {
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case <-quit:
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case <-finish:
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}
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clientC.Close()
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backendC.Close()
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<-finish
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}
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// Run starts forwarding the traffic using SCTP.
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func (proxy *SCTPProxy) Run() {
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quit := make(chan bool)
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defer close(quit)
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for {
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client, err := proxy.listener.Accept()
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if err != nil {
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log.Printf("Stopping proxy on sctp/%v for sctp/%v (%s)", proxy.frontendAddr, proxy.backendAddr, err)
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return
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}
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go proxy.clientLoop(client.(*sctp.SCTPConn), quit)
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}
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}
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// Close stops forwarding the traffic.
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func (proxy *SCTPProxy) Close() { proxy.listener.Close() }
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// FrontendAddr returns the SCTP address on which the proxy is listening.
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func (proxy *SCTPProxy) FrontendAddr() net.Addr { return proxy.frontendAddr }
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// BackendAddr returns the SCTP proxied address.
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func (proxy *SCTPProxy) BackendAddr() net.Addr { return proxy.backendAddr }
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