From fd5f484ef720792a5e19c664dac42e71d96f22cf Mon Sep 17 00:00:00 2001
From: guillaumemichel <guillaume@michel.id>
Date: Wed, 29 Jan 2025 17:58:48 +0100
Subject: [PATCH] bitswap: filter interests

---
 .../sessioninterestmanager.go                 | 23 +++++++++++++++++++
 .../internal/sessionmanager/sessionmanager.go |  5 ++++
 2 files changed, 28 insertions(+)

diff --git a/bitswap/client/internal/sessioninterestmanager/sessioninterestmanager.go b/bitswap/client/internal/sessioninterestmanager/sessioninterestmanager.go
index e8c27937c..702c5ee27 100644
--- a/bitswap/client/internal/sessioninterestmanager/sessioninterestmanager.go
+++ b/bitswap/client/internal/sessioninterestmanager/sessioninterestmanager.go
@@ -177,3 +177,26 @@ func (sim *SessionInterestManager) InterestedSessions(keySets ...[]cid.Cid) []ui
 	}
 	return ses
 }
+
+// Filters only the keys that are wanted by at least one session
+func (sim *SessionInterestManager) FilterInterests(keySets ...[]cid.Cid) [][]cid.Cid {
+	sim.lk.RLock()
+	defer sim.lk.RUnlock()
+
+	result := make([][]cid.Cid, len(keySets))
+	// For each set of keys
+	for i, ks := range keySets {
+		// The set of keys that at least one session is interested in
+		wanted := make([]cid.Cid, 0, len(ks))
+
+		// For each key in the set
+		for _, c := range ks {
+			// If there are any sessions interested in this key
+			if _, ok := sim.wants[c]; ok {
+				wanted = append(wanted, c)
+			}
+		}
+		result[i] = wanted
+	}
+	return result
+}
diff --git a/bitswap/client/internal/sessionmanager/sessionmanager.go b/bitswap/client/internal/sessionmanager/sessionmanager.go
index 80eac9f2f..de9f6fb40 100644
--- a/bitswap/client/internal/sessionmanager/sessionmanager.go
+++ b/bitswap/client/internal/sessionmanager/sessionmanager.go
@@ -154,6 +154,11 @@ func (sm *SessionManager) GetNextSessionID() uint64 {
 
 // ReceiveFrom is called when a new message is received
 func (sm *SessionManager) ReceiveFrom(ctx context.Context, p peer.ID, blks []cid.Cid, haves []cid.Cid, dontHaves []cid.Cid) {
+	// Keep only the keys that at least one session is interested in
+	keys := sm.sessionInterestManager.FilterInterests(blks, haves, dontHaves)
+	blks = keys[0]
+	haves = keys[1]
+	dontHaves = keys[2]
 	// Record block presence for HAVE / DONT_HAVE
 	sm.blockPresenceManager.ReceiveFrom(p, haves, dontHaves)