forked from Silverfish/proton-bridge
133 lines
3.7 KiB
Go
133 lines
3.7 KiB
Go
// Copyright (c) 2021 Proton Technologies AG
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//
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// This file is part of ProtonMail Bridge.
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//
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// ProtonMail Bridge is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// ProtonMail Bridge is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with ProtonMail Bridge. If not, see <https://www.gnu.org/licenses/>.
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package serverutil
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import (
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"time"
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"github.com/ProtonMail/proton-bridge/internal/events"
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"github.com/ProtonMail/proton-bridge/pkg/listener"
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"github.com/ProtonMail/proton-bridge/pkg/ports"
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"github.com/sirupsen/logrus"
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)
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// Server which can handle disconnected users and lost internet connection.
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type Server interface {
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HandlePanic()
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DisconnectUser(string)
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ListenRetryAndServe(int, time.Duration)
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Close()
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Port() int
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IsRunning() bool
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}
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func monitorDisconnectedUsers(s Server, l listener.Listener) {
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ch := make(chan string)
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l.Add(events.CloseConnectionEvent, ch)
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for address := range ch {
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s.DisconnectUser(address)
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}
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}
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func redirectInternetEventsToOneChannel(l listener.Listener) (isInternetOn chan bool) {
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on := make(chan string)
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l.Add(events.InternetOnEvent, on)
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off := make(chan string)
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l.Add(events.InternetOffEvent, off)
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// Redirect two channels into one. When select was used the algorithm
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// first read all on channels and then read all off channels.
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isInternetOn = make(chan bool, 20)
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go func() {
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for {
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logrus.WithField("try", <-on).Trace("Internet ON")
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isInternetOn <- true
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}
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}()
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go func() {
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for {
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logrus.WithField("try", <-off).Trace("Internet OFF")
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isInternetOn <- false
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}
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}()
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return
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}
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const (
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recheckPortAfter = 50 * time.Millisecond
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stopPortChecksAfter = 15 * time.Second
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retryListenerAfter = 5 * time.Second
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)
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func monitorInternetConnection(s Server, l listener.Listener) {
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isInternetOn := redirectInternetEventsToOneChannel(l)
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for {
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var expectedIsPortFree bool
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if <-isInternetOn {
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if s.IsRunning() {
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continue
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}
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go func() {
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defer s.HandlePanic()
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// We had issues on Mac that from time to time something
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// blocked our port for a bit after we closed IMAP server
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// due to connection issues.
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// Restart always helped, so we do retry to not bother user.
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s.ListenRetryAndServe(10, retryListenerAfter)
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}()
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expectedIsPortFree = false
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} else {
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if !s.IsRunning() {
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continue
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}
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s.Close()
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expectedIsPortFree = true
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}
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start := time.Now()
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for {
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isPortFree := ports.IsPortFree(s.Port())
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logrus.
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WithField("port", s.Port()).
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WithField("isFree", isPortFree).
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WithField("wantToBeFree", expectedIsPortFree).
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Trace("Check port")
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if isPortFree == expectedIsPortFree {
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break
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}
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// Safety stop if something went wrong.
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if time.Since(start) > stopPortChecksAfter {
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logrus.WithField("expectedIsPortFree", expectedIsPortFree).Warn("Server start/stop check timeouted")
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break
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}
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time.Sleep(recheckPortAfter)
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}
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}
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}
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// ListenAndServe starts the server and keeps it on based on internet
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// availability. It also monitors and disconnect users if requested.
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func ListenAndServe(s Server, l listener.Listener) {
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go monitorDisconnectedUsers(s, l)
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go monitorInternetConnection(s, l)
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// When starting the Bridge, we don't want to retry to notify user
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// quickly about the issue. Very probably retry will not help anyway.
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s.ListenRetryAndServe(0, 0)
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}
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