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peermap.go
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peermap.go
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// Copyright 2015 The Chihaya Authors. All rights reserved.
// Use of this source code is governed by the BSD 2-Clause license,
// which can be found in the LICENSE file.
package models
import (
"net"
"sync"
"sync/atomic"
"github.com/chihaya/chihaya/config"
"github.com/chihaya/chihaya/stats"
)
// PeerMap is a thread-safe map from PeerKeys to Peers. When PreferredSubnet is
// enabled, it is a thread-safe map of maps from MaskedIPs to Peerkeys to Peers.
type PeerMap struct {
Peers map[string]map[PeerKey]Peer `json:"peers"`
Seeders bool `json:"seeders"`
Config config.SubnetConfig `json:"config"`
Size int32 `json:"size"`
sync.RWMutex
}
// NewPeerMap initializes the map for a new PeerMap.
func NewPeerMap(seeders bool, cfg *config.Config) *PeerMap {
pm := &PeerMap{
Peers: make(map[string]map[PeerKey]Peer),
Seeders: seeders,
Config: cfg.NetConfig.SubnetConfig,
}
if !pm.Config.PreferredSubnet {
pm.Peers[""] = make(map[PeerKey]Peer)
}
return pm
}
// Contains is true if a peer is contained with a PeerMap.
func (pm *PeerMap) Contains(pk PeerKey) bool {
pm.RLock()
defer pm.RUnlock()
if pm.Config.PreferredSubnet {
maskedIP := pm.mask(pk.IP())
peers, exists := pm.Peers[maskedIP]
if !exists {
return false
}
_, exists = peers[pk]
return exists
}
_, exists := pm.Peers[""][pk]
return exists
}
func (pm *PeerMap) mask(ip net.IP) string {
if !pm.Config.PreferredSubnet {
return ""
}
var maskedIP net.IP
if len(ip) == net.IPv6len {
maskedIP = ip.Mask(net.CIDRMask(pm.Config.PreferredIPv6Subnet, 128))
} else {
maskedIP = ip.Mask(net.CIDRMask(pm.Config.PreferredIPv4Subnet, 32))
}
return maskedIP.String()
}
// LookUp is a thread-safe read from a PeerMap.
func (pm *PeerMap) LookUp(pk PeerKey) (peer Peer, exists bool) {
pm.RLock()
defer pm.RUnlock()
maskedIP := pm.mask(pk.IP())
peers, exists := pm.Peers[maskedIP]
if !exists {
return Peer{}, false
}
peer, exists = peers[pk]
return
}
// Put is a thread-safe write to a PeerMap.
func (pm *PeerMap) Put(p Peer) {
pm.Lock()
defer pm.Unlock()
maskedIP := pm.mask(p.IP)
_, exists := pm.Peers[maskedIP]
if !exists {
pm.Peers[maskedIP] = make(map[PeerKey]Peer)
}
_, exists = pm.Peers[maskedIP][p.Key()]
if !exists {
atomic.AddInt32(&(pm.Size), 1)
}
pm.Peers[maskedIP][p.Key()] = p
}
// Delete is a thread-safe delete from a PeerMap.
func (pm *PeerMap) Delete(pk PeerKey) {
pm.Lock()
defer pm.Unlock()
maskedIP := pm.mask(pk.IP())
_, exists := pm.Peers[maskedIP][pk]
if exists {
atomic.AddInt32(&(pm.Size), -1)
delete(pm.Peers[maskedIP], pk)
}
}
// Len returns the number of peers within a PeerMap.
func (pm *PeerMap) Len() int {
return int(atomic.LoadInt32(&pm.Size))
}
// Purge iterates over all of the peers within a PeerMap and deletes them if
// they are older than the provided time.
func (pm *PeerMap) Purge(unixtime int64) {
pm.Lock()
defer pm.Unlock()
for _, subnetmap := range pm.Peers {
for key, peer := range subnetmap {
if peer.LastAnnounce <= unixtime {
atomic.AddInt32(&(pm.Size), -1)
delete(subnetmap, key)
if pm.Seeders {
stats.RecordPeerEvent(stats.ReapedSeed, peer.HasIPv6())
} else {
stats.RecordPeerEvent(stats.ReapedLeech, peer.HasIPv6())
}
}
}
}
}
// AppendPeers adds peers to given IPv4 or IPv6 lists.
func (pm *PeerMap) AppendPeers(ipv4s, ipv6s PeerList, ann *Announce, wanted int) (PeerList, PeerList) {
maskedIP := pm.mask(ann.Peer.IP)
pm.RLock()
defer pm.RUnlock()
count := 0
// Attempt to append all the peers in the same subnet.
for _, peer := range pm.Peers[maskedIP] {
if count >= wanted {
break
} else if peersEquivalent(&peer, ann.Peer) {
continue
} else {
count += AppendPeer(&ipv4s, &ipv6s, ann, &peer)
}
}
// Add any more peers out of the other subnets.
for subnet, peers := range pm.Peers {
if subnet == maskedIP {
continue
} else {
for _, peer := range peers {
if count >= wanted {
break
} else if peersEquivalent(&peer, ann.Peer) {
continue
} else {
count += AppendPeer(&ipv4s, &ipv6s, ann, &peer)
}
}
}
}
return ipv4s, ipv6s
}
// AppendPeer adds a peer to its corresponding peerlist.
func AppendPeer(ipv4s, ipv6s *PeerList, ann *Announce, peer *Peer) int {
if ann.HasIPv6() && peer.HasIPv6() {
*ipv6s = append(*ipv6s, *peer)
return 1
} else if ann.Config.RespectAF && ann.HasIPv4() && peer.HasIPv4() {
*ipv4s = append(*ipv4s, *peer)
return 1
} else if !ann.Config.RespectAF && peer.HasIPv4() {
*ipv4s = append(*ipv4s, *peer)
return 1
}
return 0
}
// peersEquivalent checks if two peers represent the same entity.
func peersEquivalent(a, b *Peer) bool {
return a.ID == b.ID
}