-
Notifications
You must be signed in to change notification settings - Fork 241
/
connmanager.go
271 lines (242 loc) · 7.08 KB
/
connmanager.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
package mailservers
import (
"sync"
"time"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/status-im/status-go/eth-node/types"
)
const (
peerEventsBuffer = 10 // sufficient buffer to avoid blocking a p2p feed.
whisperEventsBuffer = 20 // sufficient buffer to avod blocking a eventSub envelopes feed.
)
// PeerAdderRemover is an interface for adding or removing peers.
type PeerAdderRemover interface {
AddPeer(node *enode.Node)
RemovePeer(node *enode.Node)
}
// PeerEventsSubscriber interface to subscribe for p2p.PeerEvent's.
type PeerEventsSubscriber interface {
SubscribeEvents(chan *p2p.PeerEvent) event.Subscription
}
// EnvelopeEventSubscriber interface to subscribe for types.EnvelopeEvent's.
type EnvelopeEventSubscriber interface {
SubscribeEnvelopeEvents(chan<- types.EnvelopeEvent) types.Subscription
}
type p2pServer interface {
PeerAdderRemover
PeerEventsSubscriber
}
// NewConnectionManager creates an instance of ConnectionManager.
func NewConnectionManager(server p2pServer, eventSub EnvelopeEventSubscriber, target, maxFailures int, timeout time.Duration) *ConnectionManager {
return &ConnectionManager{
server: server,
eventSub: eventSub,
connectedTarget: target,
maxFailures: maxFailures,
notifications: make(chan []*enode.Node),
timeoutWaitAdded: timeout,
}
}
// ConnectionManager manages keeps target of peers connected.
type ConnectionManager struct {
wg sync.WaitGroup
quit chan struct{}
server p2pServer
eventSub EnvelopeEventSubscriber
notifications chan []*enode.Node
connectedTarget int
timeoutWaitAdded time.Duration
maxFailures int
}
// Notify sends a non-blocking notification about new nodes.
func (ps *ConnectionManager) Notify(nodes []*enode.Node) {
ps.wg.Add(1)
go func() {
select {
case ps.notifications <- nodes:
case <-ps.quit:
}
ps.wg.Done()
}()
}
// Start subscribes to a p2p server and handles new peers and state updates for those peers.
func (ps *ConnectionManager) Start() {
ps.quit = make(chan struct{})
ps.wg.Add(1)
go func() {
state := newInternalState(ps.server, ps.connectedTarget, ps.timeoutWaitAdded)
events := make(chan *p2p.PeerEvent, peerEventsBuffer)
sub := ps.server.SubscribeEvents(events)
whisperEvents := make(chan types.EnvelopeEvent, whisperEventsBuffer)
whisperSub := ps.eventSub.SubscribeEnvelopeEvents(whisperEvents)
requests := map[types.Hash]struct{}{}
failuresPerServer := map[types.EnodeID]int{}
defer sub.Unsubscribe()
defer whisperSub.Unsubscribe()
defer ps.wg.Done()
for {
select {
case <-ps.quit:
return
case err := <-sub.Err():
log.Error("retry after error subscribing to p2p events", "error", err)
return
case err := <-whisperSub.Err():
log.Error("retry after error suscribing to eventSub events", "error", err)
return
case newNodes := <-ps.notifications:
state.processReplacement(newNodes, events)
case ev := <-events:
processPeerEvent(state, ev)
case ev := <-whisperEvents:
// TODO treat failed requests the same way as expired
switch ev.Event {
case types.EventMailServerRequestSent:
requests[ev.Hash] = struct{}{}
case types.EventMailServerRequestCompleted:
// reset failures count on first success
failuresPerServer[ev.Peer] = 0
delete(requests, ev.Hash)
case types.EventMailServerRequestExpired:
_, exist := requests[ev.Hash]
if !exist {
continue
}
failuresPerServer[ev.Peer]++
log.Debug("request to a mail server expired, disconnect a peer", "address", ev.Peer)
if failuresPerServer[ev.Peer] >= ps.maxFailures {
state.nodeDisconnected(ev.Peer)
}
}
}
}
}()
}
// Stop gracefully closes all background goroutines and waits until they finish.
func (ps *ConnectionManager) Stop() {
if ps.quit == nil {
return
}
select {
case <-ps.quit:
return
default:
}
close(ps.quit)
ps.wg.Wait()
ps.quit = nil
}
func (state *internalState) processReplacement(newNodes []*enode.Node, events <-chan *p2p.PeerEvent) {
replacement := map[types.EnodeID]*enode.Node{}
for _, n := range newNodes {
replacement[types.EnodeID(n.ID())] = n
}
state.replaceNodes(replacement)
if state.ReachedTarget() {
log.Debug("already connected with required target", "target", state.target)
return
}
if state.timeout != 0 {
log.Debug("waiting defined timeout to establish connections",
"timeout", state.timeout, "target", state.target)
timer := time.NewTimer(state.timeout)
waitForConnections(state, timer.C, events)
timer.Stop()
}
}
func newInternalState(srv PeerAdderRemover, target int, timeout time.Duration) *internalState {
return &internalState{
options: options{target: target, timeout: timeout},
srv: srv,
connected: map[types.EnodeID]struct{}{},
currentNodes: map[types.EnodeID]*enode.Node{},
}
}
type options struct {
target int
timeout time.Duration
}
type internalState struct {
options
srv PeerAdderRemover
connected map[types.EnodeID]struct{}
currentNodes map[types.EnodeID]*enode.Node
}
func (state *internalState) ReachedTarget() bool {
return len(state.connected) >= state.target
}
func (state *internalState) replaceNodes(new map[types.EnodeID]*enode.Node) {
for nid, n := range state.currentNodes {
if _, exist := new[nid]; !exist {
delete(state.connected, nid)
state.srv.RemovePeer(n)
}
}
if !state.ReachedTarget() {
for _, n := range new {
state.srv.AddPeer(n)
}
}
state.currentNodes = new
}
func (state *internalState) nodeAdded(peer types.EnodeID) {
n, exist := state.currentNodes[peer]
if !exist {
return
}
if state.ReachedTarget() {
state.srv.RemovePeer(n)
} else {
state.connected[types.EnodeID(n.ID())] = struct{}{}
}
}
func (state *internalState) nodeDisconnected(peer types.EnodeID) {
n, exist := state.currentNodes[peer] // unrelated event
if !exist {
return
}
_, exist = state.connected[peer] // check if already disconnected
if !exist {
return
}
if len(state.currentNodes) == 1 { // keep node connected if we don't have another choice
return
}
state.srv.RemovePeer(n) // remove peer permanently, otherwise p2p.Server will try to reconnect
delete(state.connected, peer)
if !state.ReachedTarget() { // try to connect with any other selected (but not connected) node
for nid, n := range state.currentNodes {
_, exist := state.connected[nid]
if exist || peer == nid {
continue
}
state.srv.AddPeer(n)
}
}
}
func processPeerEvent(state *internalState, ev *p2p.PeerEvent) {
switch ev.Type {
case p2p.PeerEventTypeAdd:
log.Debug("connected to a mailserver", "address", ev.Peer)
state.nodeAdded(types.EnodeID(ev.Peer))
case p2p.PeerEventTypeDrop:
log.Debug("mailserver disconnected", "address", ev.Peer)
state.nodeDisconnected(types.EnodeID(ev.Peer))
}
}
func waitForConnections(state *internalState, timeout <-chan time.Time, events <-chan *p2p.PeerEvent) {
for {
select {
case ev := <-events:
processPeerEvent(state, ev)
if state.ReachedTarget() {
return
}
case <-timeout:
return
}
}
}