"sync"
"github.com/anacrolix/dht/v2/krpc"
+
pp "github.com/anacrolix/torrent/peer_protocol"
)
// represents a single connection (t=pexAdd) or disconnection (t=pexDrop) event
type pexEvent struct {
t pexEventType
- addr net.Addr
+ addr PeerRemoteAddr
f pp.PexPeerFlags
+ next *pexEvent // event feed list
}
// facilitates efficient de-duplication while generating PEX messages
type addrKey string
// Returns the key to use to identify a given addr in the factory.
-func (me *pexMsgFactory) addrKey(addr net.Addr) addrKey {
+func (me *pexMsgFactory) addrKey(addr PeerRemoteAddr) addrKey {
return addrKey(addr.String())
}
-func addrEqual(a, b *krpc.NodeAddr) bool {
- return a.IP.Equal(b.IP) && a.Port == b.Port
-}
-
-func addrIndex(v []krpc.NodeAddr, a *krpc.NodeAddr) int {
- for i := range v {
- if addrEqual(&v[i], a) {
- return i
- }
- }
- return -1
-}
-
// Returns whether the entry was added (we can check if we're cancelling out another entry and so
// won't hit the limit consuming this event).
func (me *pexMsgFactory) add(e pexEvent) {
switch {
case addr.IP.To4() != nil:
if _, ok := me.dropped[key]; ok {
- if i := addrIndex(m.Dropped.NodeAddrs(), &addr); i >= 0 {
+ if i := m.Dropped.Index(addr); i >= 0 {
m.Dropped = append(m.Dropped[:i], m.Dropped[i+1:]...)
}
delete(me.dropped, key)
m.AddedFlags = append(m.AddedFlags, e.f)
case len(addr.IP) == net.IPv6len:
if _, ok := me.dropped[key]; ok {
- if i := addrIndex(m.Dropped6.NodeAddrs(), &addr); i >= 0 {
+ if i := m.Dropped6.Index(addr); i >= 0 {
m.Dropped6 = append(m.Dropped6[:i], m.Dropped6[i+1:]...)
}
delete(me.dropped, key)
switch {
case addr.IP.To4() != nil:
if _, ok := me.added[key]; ok {
- if i := addrIndex(m.Added.NodeAddrs(), &addr); i >= 0 {
+ if i := m.Added.Index(addr); i >= 0 {
m.Added = append(m.Added[:i], m.Added[i+1:]...)
m.AddedFlags = append(m.AddedFlags[:i], m.AddedFlags[i+1:]...)
}
m.Dropped = append(m.Dropped, addr)
case len(addr.IP) == net.IPv6len:
if _, ok := me.added[key]; ok {
- if i := addrIndex(m.Added6.NodeAddrs(), &addr); i >= 0 {
+ if i := m.Added6.Index(addr); i >= 0 {
m.Added6 = append(m.Added6[:i], m.Added6[i+1:]...)
m.Added6Flags = append(m.Added6Flags[:i], m.Added6Flags[i+1:]...)
}
me.dropped[key] = struct{}{}
}
-func (me *pexMsgFactory) addEvent(event pexEvent) {
+func (me *pexMsgFactory) append(event pexEvent) {
switch event.t {
case pexAdd:
me.add(event)
}
}
-func (me *pexMsgFactory) PexMsg() pp.PexMsg {
- return me.msg
+func (me *pexMsgFactory) PexMsg() *pp.PexMsg {
+ return &me.msg
}
// Convert an arbitrary torrent peer Addr into one that can be represented by the compact addr
// format.
-func nodeAddr(addr net.Addr) (_ krpc.NodeAddr, ok bool) {
- ipport, ok := tryIpPortFromNetAddr(addr)
- if !ok {
- return
- }
- return krpc.NodeAddr{IP: shortestIP(ipport.IP), Port: ipport.Port}, true
-}
-
-// mainly for the krpc marshallers
-func shortestIP(ip net.IP) net.IP {
- if ip4 := ip.To4(); ip4 != nil {
- return ip4
- }
- return ip
+func nodeAddr(addr PeerRemoteAddr) (krpc.NodeAddr, bool) {
+ ipport, _ := tryIpPortFromNetAddr(addr)
+ ok := ipport.IP != nil
+ return krpc.NodeAddr{IP: ipport.IP, Port: ipport.Port}, ok
}
// Per-torrent PEX state
type pexState struct {
- ev []pexEvent // event feed, append-only
- hold []pexEvent // delayed drops
- nc int // net number of alive conns
- initCache pexMsgFactory // last generated initial message
- initSeq int // number of events which went into initCache
- initLock sync.RWMutex // serialise access to initCache and initSeq
+ sync.RWMutex
+ tail *pexEvent // event feed list
+ hold []pexEvent // delayed drops
+ nc int // net number of alive conns
+ msg0 pexMsgFactory // initial message
}
// Reset wipes the state clean, releasing resources. Called from Torrent.Close().
func (s *pexState) Reset() {
- s.ev = nil
+ s.Lock()
+ defer s.Unlock()
+ s.tail = nil
s.hold = nil
s.nc = 0
- s.initLock.Lock()
- s.initCache = pexMsgFactory{}
- s.initSeq = 0
- s.initLock.Unlock()
+ s.msg0 = pexMsgFactory{}
+}
+
+func (s *pexState) append(e *pexEvent) {
+ if s.tail != nil {
+ s.tail.next = e
+ }
+ s.tail = e
+ s.msg0.append(*e)
}
func (s *pexState) Add(c *PeerConn) {
+ s.Lock()
+ defer s.Unlock()
s.nc++
if s.nc >= pexTargAdded {
- s.ev = append(s.ev, s.hold...)
+ for _, e := range s.hold {
+ ne := e
+ s.append(&ne)
+ }
s.hold = s.hold[:0]
}
e := c.pexEvent(pexAdd)
- s.ev = append(s.ev, e)
c.pex.Listed = true
+ s.append(&e)
}
func (s *pexState) Drop(c *PeerConn) {
// skip connections which were not previously Added
return
}
+ s.Lock()
+ defer s.Unlock()
e := c.pexEvent(pexDrop)
s.nc--
if s.nc < pexTargAdded && len(s.hold) < pexMaxHold {
s.hold = append(s.hold, e)
} else {
- s.ev = append(s.ev, e)
+ s.append(&e)
}
}
-// Generate a PEX message based on the event feed. Also returns an index to pass to the subsequent
-// calls, producing incremental deltas.
-func (s *pexState) Genmsg(start int) (pp.PexMsg, int) {
- if start == 0 {
- return s.genmsg0()
+// Generate a PEX message based on the event feed.
+// Also returns a pointer to pass to the subsequent calls
+// to produce incremental deltas.
+func (s *pexState) Genmsg(start *pexEvent) (pp.PexMsg, *pexEvent) {
+ s.RLock()
+ defer s.RUnlock()
+ if start == nil {
+ return *s.msg0.PexMsg(), s.tail
}
-
- var factory pexMsgFactory
- n := start
- for _, e := range s.ev[start:] {
- if start > 0 && factory.DeltaLen() >= pexMaxDelta {
+ var msg pexMsgFactory
+ last := start
+ for e := start.next; e != nil; e = e.next {
+ if msg.DeltaLen() >= pexMaxDelta {
break
}
- factory.addEvent(e)
- n++
+ msg.append(*e)
+ last = e
}
- return factory.PexMsg(), n
+ return *msg.PexMsg(), last
}
-func (s *pexState) genmsg0() (pp.PexMsg, int) {
- s.initLock.Lock()
- for _, e := range s.ev[s.initSeq:] {
- s.initCache.addEvent(e)
- s.initSeq++
+// The same as Genmsg but just counts up the distinct events that haven't been sent.
+func (s *pexState) numPending(start *pexEvent) (num int) {
+ s.RLock()
+ defer s.RUnlock()
+ if start == nil {
+ return s.msg0.PexMsg().Len()
+ }
+ for e := start.next; e != nil; e = e.next {
+ num++
}
- s.initLock.Unlock()
- s.initLock.RLock()
- n := s.initSeq
- msg := s.initCache.PexMsg()
- s.initLock.RUnlock()
- return msg, n
+ return
}