From e4a8a2ed651bd745b03bb11073c06c0a559fbeb0 Mon Sep 17 00:00:00 2001
From: Jeromy <jeromyj@gmail.com>
Date: Sun, 7 Dec 2014 20:54:31 +0000
Subject: [PATCH] same block cant be sent twice to a peer within a certain time
 period

---
 exchange/bitswap/strategy/ledger.go   | 4 ++--
 exchange/bitswap/strategy/strategy.go | 9 ++++++---
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/exchange/bitswap/strategy/ledger.go b/exchange/bitswap/strategy/ledger.go
index 525b6af56..84e92d035 100644
--- a/exchange/bitswap/strategy/ledger.go
+++ b/exchange/bitswap/strategy/ledger.go
@@ -16,7 +16,7 @@ func newLedger(p peer.Peer, strategy strategyFunc) *ledger {
 		wantList:   keySet{},
 		Strategy:   strategy,
 		Partner:    p,
-		sentToPeer: make(map[u.Key]struct{}),
+		sentToPeer: make(map[u.Key]time.Time),
 	}
 }
 
@@ -43,7 +43,7 @@ type ledger struct {
 
 	// sentToPeer is a set of keys to ensure we dont send duplicate blocks
 	// to a given peer
-	sentToPeer map[u.Key]struct{}
+	sentToPeer map[u.Key]time.Time
 
 	Strategy strategyFunc
 }
diff --git a/exchange/bitswap/strategy/strategy.go b/exchange/bitswap/strategy/strategy.go
index af1c35848..fe7414caa 100644
--- a/exchange/bitswap/strategy/strategy.go
+++ b/exchange/bitswap/strategy/strategy.go
@@ -10,6 +10,8 @@ import (
 	u "github.com/jbenet/go-ipfs/util"
 )
 
+const resendTimeoutPeriod = time.Minute
+
 var log = u.Logger("strategy")
 
 // TODO niceness should be on a per-peer basis. Use-case: Certain peers are
@@ -66,8 +68,9 @@ func (s *strategist) ShouldSendBlockToPeer(k u.Key, p peer.Peer) bool {
 
 	ledger := s.ledger(p)
 
-	// Dont resend blocks
-	if _, ok := ledger.sentToPeer[k]; ok {
+	// Dont resend blocks within a certain time period
+	t, ok := ledger.sentToPeer[k]
+	if ok && t.Add(resendTimeoutPeriod).After(time.Now()) {
 		return false
 	}
 
@@ -79,7 +82,7 @@ func (s *strategist) BlockSentToPeer(k u.Key, p peer.Peer) {
 	defer s.lock.Unlock()
 
 	ledger := s.ledger(p)
-	ledger.sentToPeer[k] = struct{}{}
+	ledger.sentToPeer[k] = time.Now()
 }
 
 func (s *strategist) Seed(int64) {