This adds two new configuration options: // The number of connections at which we stop trying to connect to more // devices, zero meaning no limit. Does not affect incoming connections. ConnectionLimitEnough int // The maximum number of connections which we will allow in total, zero // meaning no limit. Affects incoming connections and prevents // attempting outgoing connections. ConnectionLimitMax int These can be used to limit the number of concurrent connections in various ways.
244 lines
5.9 KiB
Go
244 lines
5.9 KiB
Go
// Copyright (C) 2016 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at https://mozilla.org/MPL/2.0/.
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package connections
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import (
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"context"
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"crypto/tls"
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"fmt"
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"io"
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"net"
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"net/url"
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"time"
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"github.com/syncthing/syncthing/lib/config"
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"github.com/syncthing/syncthing/lib/nat"
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"github.com/syncthing/syncthing/lib/protocol"
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"github.com/syncthing/syncthing/lib/stats"
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"github.com/thejerf/suture/v4"
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)
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type tlsConn interface {
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io.ReadWriteCloser
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ConnectionState() tls.ConnectionState
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RemoteAddr() net.Addr
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SetDeadline(time.Time) error
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SetWriteDeadline(time.Time) error
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LocalAddr() net.Addr
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}
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// internalConn is the raw TLS connection plus some metadata on where it
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// came from (type, priority).
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type internalConn struct {
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tlsConn
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connType connType
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priority int
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establishedAt time.Time
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}
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type connType int
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const (
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connTypeRelayClient connType = iota
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connTypeRelayServer
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connTypeTCPClient
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connTypeTCPServer
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connTypeQUICClient
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connTypeQUICServer
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)
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func (t connType) String() string {
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switch t {
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case connTypeRelayClient:
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return "relay-client"
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case connTypeRelayServer:
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return "relay-server"
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case connTypeTCPClient:
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return "tcp-client"
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case connTypeTCPServer:
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return "tcp-server"
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case connTypeQUICClient:
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return "quic-client"
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case connTypeQUICServer:
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return "quic-server"
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default:
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return "unknown-type"
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}
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}
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func (t connType) Transport() string {
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switch t {
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case connTypeRelayClient, connTypeRelayServer:
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return "relay"
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case connTypeTCPClient, connTypeTCPServer:
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return "tcp"
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case connTypeQUICClient, connTypeQUICServer:
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return "quic"
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default:
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return "unknown"
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}
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}
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func newInternalConn(tc tlsConn, connType connType, priority int) internalConn {
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return internalConn{
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tlsConn: tc,
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connType: connType,
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priority: priority,
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establishedAt: time.Now(),
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}
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}
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func (c internalConn) Close() error {
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// *tls.Conn.Close() does more than it says on the tin. Specifically, it
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// sends a TLS alert message, which might block forever if the
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// connection is dead and we don't have a deadline set.
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_ = c.SetWriteDeadline(time.Now().Add(250 * time.Millisecond))
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return c.tlsConn.Close()
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}
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func (c internalConn) Type() string {
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return c.connType.String()
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}
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func (c internalConn) Priority() int {
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return c.priority
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}
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func (c internalConn) Crypto() string {
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cs := c.ConnectionState()
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return fmt.Sprintf("%s-%s", tlsVersionNames[cs.Version], tlsCipherSuiteNames[cs.CipherSuite])
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}
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func (c internalConn) Transport() string {
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transport := c.connType.Transport()
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host, _, err := net.SplitHostPort(c.LocalAddr().String())
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if err != nil {
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return transport
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}
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ip := net.ParseIP(host)
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if ip == nil {
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return transport
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}
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if ip.To4() != nil {
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return transport + "4"
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}
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return transport + "6"
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}
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func (c internalConn) EstablishedAt() time.Time {
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return c.establishedAt
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}
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func (c internalConn) String() string {
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return fmt.Sprintf("%s-%s/%s/%s", c.LocalAddr(), c.RemoteAddr(), c.Type(), c.Crypto())
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}
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type dialerFactory interface {
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New(config.OptionsConfiguration, *tls.Config) genericDialer
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Priority() int
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AlwaysWAN() bool
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Valid(config.Configuration) error
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String() string
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}
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type commonDialer struct {
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trafficClass int
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reconnectInterval time.Duration
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tlsCfg *tls.Config
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}
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func (d *commonDialer) RedialFrequency() time.Duration {
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return d.reconnectInterval
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}
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type genericDialer interface {
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Dial(context.Context, protocol.DeviceID, *url.URL) (internalConn, error)
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RedialFrequency() time.Duration
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}
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type listenerFactory interface {
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New(*url.URL, config.Wrapper, *tls.Config, chan internalConn, *nat.Service) genericListener
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Valid(config.Configuration) error
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}
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type ListenerAddresses struct {
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URI *url.URL
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WANAddresses []*url.URL
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LANAddresses []*url.URL
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}
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type genericListener interface {
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suture.Service
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URI() *url.URL
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// A given address can potentially be mutated by the listener.
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// For example we bind to tcp://0.0.0.0, but that for example might return
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// tcp://gateway1.ip and tcp://gateway2.ip as WAN addresses due to there
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// being multiple gateways, and us managing to get a UPnP mapping on both
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// and tcp://192.168.0.1 and tcp://10.0.0.1 due to there being multiple
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// network interfaces. (The later case for LAN addresses is made up just
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// to provide an example)
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WANAddresses() []*url.URL
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LANAddresses() []*url.URL
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Error() error
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OnAddressesChanged(func(ListenerAddresses))
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String() string
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Factory() listenerFactory
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NATType() string
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}
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type Model interface {
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protocol.Model
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AddConnection(conn protocol.Connection, hello protocol.Hello)
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NumConnections() int
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Connection(remoteID protocol.DeviceID) (protocol.Connection, bool)
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OnHello(protocol.DeviceID, net.Addr, protocol.Hello) error
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GetHello(protocol.DeviceID) protocol.HelloIntf
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DeviceStatistics() (map[protocol.DeviceID]stats.DeviceStatistics, error)
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}
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type onAddressesChangedNotifier struct {
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callbacks []func(ListenerAddresses)
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}
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func (o *onAddressesChangedNotifier) OnAddressesChanged(callback func(ListenerAddresses)) {
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o.callbacks = append(o.callbacks, callback)
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}
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func (o *onAddressesChangedNotifier) notifyAddressesChanged(l genericListener) {
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o.notifyAddresses(ListenerAddresses{
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URI: l.URI(),
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WANAddresses: l.WANAddresses(),
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LANAddresses: l.LANAddresses(),
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})
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}
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func (o *onAddressesChangedNotifier) clearAddresses(l genericListener) {
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o.notifyAddresses(ListenerAddresses{
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URI: l.URI(),
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})
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}
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func (o *onAddressesChangedNotifier) notifyAddresses(l ListenerAddresses) {
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for _, callback := range o.callbacks {
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callback(l)
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}
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}
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type dialTarget struct {
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addr string
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dialer genericDialer
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priority int
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uri *url.URL
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deviceID protocol.DeviceID
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}
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func (t dialTarget) Dial(ctx context.Context) (internalConn, error) {
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l.Debugln("dialing", t.deviceID, t.uri, "prio", t.priority)
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return t.dialer.Dial(ctx, t.deviceID, t.uri)
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}
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