fixing some race conditions

peer/peer.go

@@ -3,6 +3,7 @@ package peer
 import (
 	"encoding/hex"
 	"time"
+	"sync"
 
 	u "github.com/jbenet/go-ipfs/util"
 	ma "github.com/jbenet/go-multiaddr"
@@ -31,7 +32,9 @@ type Map map[u.Key]*Peer
 type Peer struct {
 	ID        ID
 	Addresses []*ma.Multiaddr
-	Distance time.Duration
+
+	distance time.Duration
+	distLock sync.RWMutex
 }
 
 // Key returns the ID as a Key (string) for maps.
@@ -60,3 +63,13 @@ func (p *Peer) NetAddress(n string) *ma.Multiaddr {
 	}
 	return nil
 }
+
+func (p *Peer) GetDistance() time.Duration {
+	return p.distance
+}
+
+func (p *Peer) SetDistance(dist time.Duration) {
+	p.distLock.Lock()
+	p.distance = dist
+	p.distLock.Unlock()
+}

routing/dht/dht.go

@@ -186,6 +186,7 @@ func (dht *IpfsDHT) handleMessages() {
 
 		case err := <-dht.network.Chan.Errors:
 			u.DErr("dht err: %s", err)
+			panic(err)
 		case <-dht.shutdown:
 			checkTimeouts.Stop()
 			return

routing/dht/routing.go

@@ -48,6 +48,8 @@ func (s *IpfsDHT) PutValue(key u.Key, value []byte) error {
 }
 
 // GetValue searches for the value corresponding to given Key.
+// If the search does not succeed, a multiaddr string of a closer peer is
+// returned along with util.ErrSearchIncomplete
 func (s *IpfsDHT) GetValue(key u.Key, timeout time.Duration) ([]byte, error) {
 	var p *peer.Peer
 	p = s.routes.NearestPeer(convertKey(key))
@@ -77,7 +79,11 @@ func (s *IpfsDHT) GetValue(key u.Key, timeout time.Duration) ([]byte, error) {
 		if err != nil {
 			return nil,err
 		}
-		return pmes_out.GetValue(), nil
+		if pmes_out.GetSuccess() {
+			return pmes_out.GetValue(), nil
+		} else {
+			return pmes_out.GetValue(), u.ErrSearchIncomplete
+		}
 	}
 }
 
@@ -225,7 +231,7 @@ func (dht *IpfsDHT) Ping(p *peer.Peer, timeout time.Duration) error {
 	select {
 	case <-response_chan:
 		roundtrip := time.Since(before)
-		p.Distance = roundtrip //TODO: This isnt threadsafe
+		p.SetDistance(roundtrip)
 		u.POut("Ping took %s.", roundtrip.String())
 		return nil
 	case <-tout:

routing/dht/table.go

@@ -3,8 +3,10 @@ package dht
 import (
 	"container/list"
 	"sort"
+	"sync"
 
 	peer "github.com/jbenet/go-ipfs/peer"
+	u "github.com/jbenet/go-ipfs/util"
 )
 
 // RoutingTable defines the routing table.
@@ -13,6 +15,9 @@ type RoutingTable struct {
 	// ID of the local peer
 	local ID
 
+	// Blanket lock, refine later for better performance
+	tabLock sync.RWMutex
+
 	// kBuckets define all the fingers to other nodes.
 	Buckets []*Bucket
 	bucketsize int
@@ -29,6 +34,8 @@ func NewRoutingTable(bucketsize int, local_id ID) *RoutingTable {
 // Update adds or moves the given peer to the front of its respective bucket
 // If a peer gets removed from a bucket, it is returned
 func (rt *RoutingTable) Update(p *peer.Peer) *peer.Peer {
+	rt.tabLock.Lock()
+	defer rt.tabLock.Unlock()
 	peer_id := convertPeerID(p.ID)
 	cpl := xor(peer_id, rt.local).commonPrefixLen()
 
@@ -88,7 +95,11 @@ func (p peerSorterArr) Less(a, b int) bool {
 //
 
 func copyPeersFromList(target ID, peerArr peerSorterArr, peerList *list.List) peerSorterArr {
-	for e := peerList.Front(); e != nil; e = e.Next() {
+	if peerList == nil {
+		return peerSorterArr{}
+	}
+	e := peerList.Front()
+	for ; e != nil; {
 		p := e.Value.(*peer.Peer)
 		p_id := convertPeerID(p.ID)
 		pd := peerDistance{
@@ -96,6 +107,11 @@ func copyPeersFromList(target ID, peerArr peerSorterArr, peerList *list.List) pe
 			distance: xor(target, p_id),
 		}
 		peerArr = append(peerArr, &pd)
+		if e != nil {
+			u.POut("list element was nil.")
+			return peerArr
+		}
+		e = e.Next()
 	}
 	return peerArr
 }
@@ -112,6 +128,8 @@ func (rt *RoutingTable) NearestPeer(id ID) *peer.Peer {
 
 // Returns a list of the 'count' closest peers to the given ID
 func (rt *RoutingTable) NearestPeers(id ID, count int) []*peer.Peer {
+	rt.tabLock.RLock()
+	defer rt.tabLock.RUnlock()
 	cpl := xor(id, rt.local).commonPrefixLen()
 
 	// Get bucket at cpl index or last bucket