feat: implement ssh forwarding

internal/sshproxy/sshproxy.go

@@ -0,0 +1,37 @@
+package sshproxy
+
+type SSHProxy struct {
+	// internalPorts maps internal docker ssh ports to the corresponding external ssh ports
+	// that users use to ssh into workspaces
+	internalPorts map[int]int
+
+	connections map[int]*proxyConnection
+}
+
+func New() *SSHProxy {
+	return &SSHProxy{
+		internalPorts: map[int]int{},
+		connections:   map[int]*proxyConnection{},
+	}
+}
+
+func (p *SSHProxy) NewProxyEntryTo(toPort int) error {
+	c, err := newProxyConnection(toPort)
+	if err != nil {
+		return err
+	}
+
+	go c.start()
+
+	p.connections[toPort] = c
+	p.internalPorts[toPort] = c.externalPort
+
+	return nil
+}
+
+func (p *SSHProxy) FindExternalPort(internalPort int) int {
+	if port, ok := p.internalPorts[internalPort]; ok {
+		return port
+	}
+	return -1
+}