You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
227 lines
5.4 KiB
227 lines
5.4 KiB
package p2p
|
|
|
|
import (
|
|
"net"
|
|
"strings"
|
|
"sync"
|
|
)
|
|
|
|
// IPeerSet has a (immutable) subset of the methods of PeerSet.
|
|
type IPeerSet interface {
|
|
Has(key string) bool
|
|
Get(key string) *Peer
|
|
List() []*Peer
|
|
Size() int
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
|
|
var (
|
|
maxPeersPerIPRange = [4]int{11, 7, 5, 3} // ...
|
|
)
|
|
|
|
// PeerSet is a special structure for keeping a table of peers.
|
|
// Iteration over the peers is super fast and thread-safe.
|
|
// We also track how many peers per IP range and avoid too many
|
|
type PeerSet struct {
|
|
mtx sync.Mutex
|
|
lookup map[string]*peerSetItem
|
|
list []*Peer
|
|
connectedIPs *nestedCounter
|
|
}
|
|
|
|
type peerSetItem struct {
|
|
peer *Peer
|
|
index int
|
|
}
|
|
|
|
func NewPeerSet() *PeerSet {
|
|
return &PeerSet{
|
|
lookup: make(map[string]*peerSetItem),
|
|
list: make([]*Peer, 0, 256),
|
|
connectedIPs: NewNestedCounter(),
|
|
}
|
|
}
|
|
|
|
// Returns false if peer with key (uuid) is already in set
|
|
// or if we have too many peers from the peer's IP range
|
|
func (ps *PeerSet) Add(peer *Peer) error {
|
|
ps.mtx.Lock()
|
|
defer ps.mtx.Unlock()
|
|
if ps.lookup[peer.Key] != nil {
|
|
return ErrSwitchDuplicatePeer
|
|
}
|
|
|
|
// ensure we havent maxed out connections for the peer's IP range yet
|
|
// and update the IP range counters
|
|
if !ps.incrIPRangeCounts(peer.Host) {
|
|
return ErrSwitchMaxPeersPerIPRange
|
|
}
|
|
|
|
index := len(ps.list)
|
|
// Appending is safe even with other goroutines
|
|
// iterating over the ps.list slice.
|
|
ps.list = append(ps.list, peer)
|
|
ps.lookup[peer.Key] = &peerSetItem{peer, index}
|
|
return nil
|
|
}
|
|
|
|
func (ps *PeerSet) Has(peerKey string) bool {
|
|
ps.mtx.Lock()
|
|
defer ps.mtx.Unlock()
|
|
_, ok := ps.lookup[peerKey]
|
|
return ok
|
|
}
|
|
|
|
func (ps *PeerSet) Get(peerKey string) *Peer {
|
|
ps.mtx.Lock()
|
|
defer ps.mtx.Unlock()
|
|
item, ok := ps.lookup[peerKey]
|
|
if ok {
|
|
return item.peer
|
|
} else {
|
|
return nil
|
|
}
|
|
}
|
|
|
|
func (ps *PeerSet) Remove(peer *Peer) {
|
|
ps.mtx.Lock()
|
|
defer ps.mtx.Unlock()
|
|
item := ps.lookup[peer.Key]
|
|
if item == nil {
|
|
return
|
|
}
|
|
|
|
// update the IP range counters
|
|
ps.decrIPRangeCounts(peer.Host)
|
|
|
|
index := item.index
|
|
// Copy the list but without the last element.
|
|
// (we must copy because we're mutating the list)
|
|
newList := make([]*Peer, len(ps.list)-1)
|
|
copy(newList, ps.list)
|
|
// If it's the last peer, that's an easy special case.
|
|
if index == len(ps.list)-1 {
|
|
ps.list = newList
|
|
delete(ps.lookup, peer.Key)
|
|
return
|
|
}
|
|
|
|
// Move the last item from ps.list to "index" in list.
|
|
lastPeer := ps.list[len(ps.list)-1]
|
|
lastPeerKey := lastPeer.Key
|
|
lastPeerItem := ps.lookup[lastPeerKey]
|
|
newList[index] = lastPeer
|
|
lastPeerItem.index = index
|
|
ps.list = newList
|
|
delete(ps.lookup, peer.Key)
|
|
|
|
}
|
|
|
|
func (ps *PeerSet) Size() int {
|
|
ps.mtx.Lock()
|
|
defer ps.mtx.Unlock()
|
|
return len(ps.list)
|
|
}
|
|
|
|
// threadsafe list of peers.
|
|
func (ps *PeerSet) List() []*Peer {
|
|
ps.mtx.Lock()
|
|
defer ps.mtx.Unlock()
|
|
return ps.list
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// track the number of IPs we're connected to for each IP address range
|
|
|
|
// forms an IP address hierarchy tree with counts
|
|
// the struct itself is not thread safe and should always only be accessed with the ps.mtx locked
|
|
type nestedCounter struct {
|
|
count int
|
|
children map[string]*nestedCounter
|
|
}
|
|
|
|
func NewNestedCounter() *nestedCounter {
|
|
nc := new(nestedCounter)
|
|
nc.children = make(map[string]*nestedCounter)
|
|
return nc
|
|
}
|
|
|
|
// Check if we have too many IPs in the IP range of the incoming connection
|
|
// Thread safe
|
|
func (ps *PeerSet) HasMaxForIPRange(conn net.Conn) (ok bool) {
|
|
ps.mtx.Lock()
|
|
defer ps.mtx.Unlock()
|
|
ip, _, _ := net.SplitHostPort(conn.RemoteAddr().String())
|
|
ipBytes := strings.Split(ip, ".")
|
|
|
|
c := ps.connectedIPs
|
|
for i, ipByte := range ipBytes {
|
|
if c, ok = c.children[ipByte]; !ok {
|
|
return false
|
|
}
|
|
if maxPeersPerIPRange[i] <= c.count {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
// Increments counts for this address' IP range
|
|
// Returns false if we already have enough connections
|
|
// Not thread safe (only called by ps.Add())
|
|
func (ps *PeerSet) incrIPRangeCounts(address string) bool {
|
|
addrParts := strings.Split(address, ".")
|
|
|
|
c := ps.connectedIPs
|
|
return incrNestedCounters(c, addrParts, 0)
|
|
}
|
|
|
|
// Recursively descend the IP hierarchy, checking if we have
|
|
// max peers for each range and incrementing if not.
|
|
// Returns false if incr failed because max peers reached for some range counter.
|
|
func incrNestedCounters(c *nestedCounter, ipBytes []string, index int) bool {
|
|
ipByte := ipBytes[index]
|
|
child := c.children[ipByte]
|
|
if child == nil {
|
|
child = NewNestedCounter()
|
|
c.children[ipByte] = child
|
|
}
|
|
if index+1 < len(ipBytes) {
|
|
if !incrNestedCounters(child, ipBytes, index+1) {
|
|
return false
|
|
}
|
|
}
|
|
if maxPeersPerIPRange[index] <= child.count {
|
|
return false
|
|
} else {
|
|
child.count += 1
|
|
return true
|
|
}
|
|
}
|
|
|
|
// Decrement counts for this address' IP range
|
|
func (ps *PeerSet) decrIPRangeCounts(address string) {
|
|
addrParts := strings.Split(address, ".")
|
|
|
|
c := ps.connectedIPs
|
|
decrNestedCounters(c, addrParts, 0)
|
|
}
|
|
|
|
// Recursively descend the IP hierarchy, decrementing by one.
|
|
// If the counter is zero, deletes the child.
|
|
func decrNestedCounters(c *nestedCounter, ipBytes []string, index int) {
|
|
ipByte := ipBytes[index]
|
|
child := c.children[ipByte]
|
|
if child == nil {
|
|
log.Error("p2p/peer_set decrNestedCounters encountered a missing child counter")
|
|
return
|
|
}
|
|
if index+1 < len(ipBytes) {
|
|
decrNestedCounters(child, ipBytes, index+1)
|
|
}
|
|
child.count -= 1
|
|
if child.count <= 0 {
|
|
delete(c.children, ipByte)
|
|
}
|
|
}
|