From ea9255e972dd335c0498cbd9d71f8bf645c1e829 Mon Sep 17 00:00:00 2001
From: Boris Zbarsky <bzbarsky@apple.com>
Date: Sat, 25 Feb 2023 18:20:05 -0500
Subject: [PATCH] Address review comments.

---
 src/inet/BasicPacketFilters.h             | 14 +++++++++-----
 src/inet/tests/TestBasicPacketFilters.cpp |  2 +-
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/inet/BasicPacketFilters.h b/src/inet/BasicPacketFilters.h
index aabaf286581ec8..08f0b3fba1b5ec 100644
--- a/src/inet/BasicPacketFilters.h
+++ b/src/inet/BasicPacketFilters.h
@@ -42,7 +42,7 @@ class DropIfTooManyQueuedPacketsFilter : public chip::Inet::EndpointQueueFilter
      *
      * @param maxAllowedQueuedPackets - max number of pending-in-queue not yet processed predicate-matching packets
      */
-    DropIfTooManyQueuedPacketsFilter(int maxAllowedQueuedPackets) : mMaxAllowedQueuedPackets(maxAllowedQueuedPackets) {}
+    DropIfTooManyQueuedPacketsFilter(size_t maxAllowedQueuedPackets) : mMaxAllowedQueuedPackets(maxAllowedQueuedPackets) {}
 
     /**
      * @brief Set the predicate to use for filtering
@@ -68,7 +68,7 @@ class DropIfTooManyQueuedPacketsFilter : public chip::Inet::EndpointQueueFilter
      *
      * @param maxAllowedQueuedPackets - number of packets currently pending allowed.
      */
-    void SetMaxQueuedPacketsLimit(int maxAllowedQueuedPackets) { mMaxAllowedQueuedPackets.store(maxAllowedQueuedPackets); }
+    void SetMaxQueuedPacketsLimit(size_t maxAllowedQueuedPackets) { mMaxAllowedQueuedPackets.store(maxAllowedQueuedPackets); }
 
     /**
      * @return the total number of packets dropped so far by the filter
@@ -158,8 +158,12 @@ class DropIfTooManyQueuedPacketsFilter : public chip::Inet::EndpointQueueFilter
             return FilterOutcome::kAllowPacket;
         }
 
+        // If we ever go negative, we have mismatch ingress/egress filter via predicate and
+        // device may eventually starve.
+        VerifyOrDie(mNumQueuedPackets != 0);
+
         --mNumQueuedPackets;
-        int numQueuedPackets = mNumQueuedPackets.load();
+        size_t numQueuedPackets = mNumQueuedPackets.load();
         if (numQueuedPackets == 0)
         {
             OnLastMatchDequeued(endpoint, pktInfo, pktPayload);
@@ -176,8 +180,8 @@ class DropIfTooManyQueuedPacketsFilter : public chip::Inet::EndpointQueueFilter
 protected:
     PacketMatchPredicateFunc mPredicate = nullptr;
     void * mContext                     = nullptr;
-    std::atomic_int mNumQueuedPackets{ 0 };
-    std::atomic_int mMaxAllowedQueuedPackets{ 0 };
+    std::atomic_size_t mNumQueuedPackets{ 0 };
+    std::atomic_size_t mMaxAllowedQueuedPackets{ 0 };
     std::atomic_size_t mNumDroppedPackets{ 0u };
 };
 
diff --git a/src/inet/tests/TestBasicPacketFilters.cpp b/src/inet/tests/TestBasicPacketFilters.cpp
index c9df12d41043b2..ef07cab057eb89 100644
--- a/src/inet/tests/TestBasicPacketFilters.cpp
+++ b/src/inet/tests/TestBasicPacketFilters.cpp
@@ -38,7 +38,7 @@ using namespace chip::Inet;
 class DropIfTooManyQueuedPacketsHarness : public DropIfTooManyQueuedPacketsFilter
 {
 public:
-    DropIfTooManyQueuedPacketsHarness(int maxAllowedQueuedPackets) : DropIfTooManyQueuedPacketsFilter(maxAllowedQueuedPackets) {}
+    DropIfTooManyQueuedPacketsHarness(size_t maxAllowedQueuedPackets) : DropIfTooManyQueuedPacketsFilter(maxAllowedQueuedPackets) {}
 
     void OnDropped(const void * endpoint, const IPPacketInfo & pktInfo,
                    const chip::System::PacketBufferHandle & pktPayload) override