zcash: move goroutine spawn to caller rather than callback

zcash/client.go

@@ -4,9 +4,12 @@ import (
 	"log"
 	"net"
 	"os"
+	"runtime"
+	"strconv"
 	"sync"
 	"time"
 
+	"github.com/btcsuite/btcd/addrmgr"
 	"github.com/btcsuite/btcd/peer"
 	"github.com/btcsuite/btcd/wire"
 
@@ -51,6 +54,9 @@ type Seeder struct {
 
 	// The set of known addresses
 	addrBook *AddressBook
+
+	// The queue of incoming potential addresses
+	addrQueue chan *wire.NetAddress
 }
 
 func NewSeeder(network network.Network) (*Seeder, error) {
@@ -68,6 +74,7 @@ func NewSeeder(network network.Network) (*Seeder, error) {
 		pendingPeers:     NewPeerMap(),
 		livePeers:        NewPeerMap(),
 		addrBook:         NewAddressBook(),
+		addrQueue:        make(chan *wire.NetAddress),
 	}
 
 	newSeeder.config.Listeners.OnVerAck = newSeeder.onVerAck
@@ -96,6 +103,7 @@ func newTestSeeder(network network.Network) (*Seeder, error) {
 		pendingPeers:     NewPeerMap(),
 		livePeers:        NewPeerMap(),
 		addrBook:         NewAddressBook(),
+		addrQueue:        make(chan *wire.NetAddress),
 	}
 
 	newSeeder.config.Listeners.OnVerAck = newSeeder.onVerAck
@@ -260,13 +268,78 @@ func (s *Seeder) DisconnectAllPeers() {
 	})
 }
 
-// RequestAddresses sends a request for more addresses to every peer we're connected to.
+// RequestAddresses sends a request for more addresses to every peer we're connected to,
+// then checks to make sure the addresses that come back are usable before adding them to
+// the address book.
 func (s *Seeder) RequestAddresses() {
 	s.livePeers.Range(func(key PeerKey, p *peer.Peer) bool {
 		s.logger.Printf("Requesting addresses from peer %s", p.Addr())
 		p.QueueMessage(wire.NewMsgGetAddr(), nil)
 		return true
 	})
+
+	// There's a sync concern: if this is called repeatedly you could end up broadcasting
+	// GetAddr messages to briefly live trial connections without meaning to. It's
+	// meant to be run on a timer that takes longer to fire than it takes to check addresses.
+
+	for i := 0; i < runtime.NumCPU()*2; i++ {
+		go func() {
+			var na *wire.NetAddress
+			for {
+				select {
+				case next := <-s.addrQueue:
+					// Pull the next address off the queue
+					na = next
+				case <-time.After(1 * time.Second):
+					// Or die if there wasn't one
+					return
+				}
+
+				// Note that AllowSelfConns is only exposed in a fork of btcd
+				// pending https://github.com/btcsuite/btcd/pull/1481, which
+				// is why the module `replace`s btcd.
+				if !addrmgr.IsRoutable(na) && !s.config.AllowSelfConns {
+					s.logger.Printf("Got bad addr %s:%d from peer %s", na.IP, na.Port, "<placeholder>")
+					// TODO blacklist peers who give us crap addresses
+					//s.DisconnectAndBlacklist(peerKeyFromPeer(p))
+					continue
+				}
+
+				potentialPeer := peerKeyFromNA(na)
+
+				if s.addrBook.IsKnown(potentialPeer) {
+					s.logger.Printf("Already knew about %s:%d", na.IP, na.Port)
+					continue
+				}
+
+				if s.addrBook.IsBlacklisted(potentialPeer) {
+					s.logger.Printf("Previously blacklisted %s:%d", na.IP, na.Port)
+					continue
+				}
+
+				portString := strconv.Itoa(int(na.Port))
+				err := s.Connect(na.IP.String(), portString)
+
+				if err != nil {
+					if err == ErrRepeatConnection {
+						//s.logger.Printf("Got duplicate peer %s:%d.", na.IP, na.Port)
+						continue
+					}
+
+					// Blacklist the potential peer. We might try to connect again later,
+					// since we assume IsRoutable filtered out the truly wrong ones.
+					s.logger.Printf("Got unusable peer %s:%d. Error: %s", na.IP, na.Port, err)
+					s.addrBook.Blacklist(potentialPeer)
+					continue
+				}
+
+				s.DisconnectPeer(potentialPeer)
+
+				s.logger.Printf("Successfully learned about %s:%d.", na.IP, na.Port)
+				s.addrBook.Add(potentialPeer)
+			}
+		}()
+	}
 }
 
 // WaitForAddresses waits for n addresses to be confirmed and available in the address book.
@@ -285,5 +358,3 @@ func (s *Seeder) WaitForAddresses(n int, timeout time.Duration) error {
 func (s *Seeder) Ready() bool {
 	return s.WaitForAddresses(minimumReadyAddresses, 1*time.Millisecond) == nil
 }
-
-//func (s *Seeder) Addresses(count int) []

zcash/client_callbacks.go

@@ -1,11 +1,6 @@
 package zcash
 
 import (
-	"runtime"
-	"strconv"
-	"time"
-
-	"github.com/btcsuite/btcd/addrmgr"
 	"github.com/btcsuite/btcd/peer"
 	"github.com/btcsuite/btcd/wire"
 )
@@ -54,67 +49,9 @@ func (s *Seeder) onAddr(p *peer.Peer, msg *wire.MsgAddr) {
 
 	s.logger.Printf("Got %d addrs from peer %s", len(msg.AddrList), p.Addr())
 
-	queue := make(chan *wire.NetAddress, len(msg.AddrList))
+	//queue := make(chan *wire.NetAddress, len(msg.AddrList))
 
 	for _, na := range msg.AddrList {
-		queue <- na
-	}
-
-	for i := 0; i < runtime.NumCPU()*2; i++ {
-		go func() {
-			var na *wire.NetAddress
-			for {
-				select {
-				case next := <-queue:
-					// Pull the next address off the queue
-					na = next
-				case <-time.After(1 * time.Second):
-					// Or die if there wasn't one
-					return
-				}
-
-				// Note that AllowSelfConns is only exposed in a fork of btcd
-				// pending https://github.com/btcsuite/btcd/pull/1481, which
-				// is why the module `replace`s btcd.
-				if !addrmgr.IsRoutable(na) && !s.config.AllowSelfConns {
-					s.logger.Printf("Got bad addr %s:%d from peer %s", na.IP, na.Port, p.Addr())
-					s.DisconnectAndBlacklist(peerKeyFromPeer(p))
-					continue
-				}
-
-				potentialPeer := peerKeyFromNA(na)
-
-				if s.addrBook.IsKnown(potentialPeer) {
-					s.logger.Printf("Already knew about %s:%d", na.IP, na.Port)
-					continue
-				}
-
-				if s.addrBook.IsBlacklisted(potentialPeer) {
-					s.logger.Printf("Previously blacklisted %s:%d", na.IP, na.Port)
-					continue
-				}
-
-				portString := strconv.Itoa(int(na.Port))
-				err := s.Connect(na.IP.String(), portString)
-
-				if err != nil {
-					if err == ErrRepeatConnection {
-						s.logger.Printf("Got duplicate peer %s:%d from peer %s. Error: %s", na.IP, na.Port, p.Addr(), err)
-						continue
-					}
-
-					// Blacklist the potential peer. We might try to connect again later,
-					// since we assume IsRoutable filtered out the truly wrong ones.
-					s.logger.Printf("Got unusable peer %s:%d from peer %s. Error: %s", na.IP, na.Port, p.Addr(), err)
-					s.addrBook.Blacklist(potentialPeer)
-					continue
-				}
-
-				s.DisconnectPeer(potentialPeer)
-
-				s.logger.Printf("Successfully learned about %s:%d from %s.", na.IP, na.Port, p.Addr())
-				s.addrBook.Add(potentialPeer)
-			}
-		}()
+		s.addrQueue <- na
 	}
 }