From 5537680e54c8d47a45dc9b8c638de5b80fd92b64 Mon Sep 17 00:00:00 2001
From: Kevin Schoedel <67607049+kpschoedel@users.noreply.github.com>
Date: Fri, 9 Jul 2021 10:45:28 -0400
Subject: [PATCH] Fix PacketBuffer allocation size when using LwIP (#8226)

#### Problem

LwIP `pbuf_alloc()` was called with a size including the `struct pbuf`
header, but expects the size to exclude that.

#### Change overview

Call `pbuf_alloc()` with the correct size.

This imports a fragment of https://github.com/openweave/openweave-core/pull/608

#### Testing

Added `PacketBuffer::kMaxSizeWithoutReserve` to the cases checked
by `PacketBufferTest::CheckNew()`.
---
 src/system/SystemPacketBuffer.cpp           | 2 +-
 src/system/tests/TestSystemPacketBuffer.cpp | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/system/SystemPacketBuffer.cpp b/src/system/SystemPacketBuffer.cpp
index 076410d39af4f6..4cc91b5dff326e 100644
--- a/src/system/SystemPacketBuffer.cpp
+++ b/src/system/SystemPacketBuffer.cpp
@@ -466,7 +466,7 @@ PacketBufferHandle PacketBufferHandle::New(size_t aAvailableSize, uint16_t aRese
 #if CHIP_SYSTEM_PACKETBUFFER_STORE == CHIP_SYSTEM_PACKETBUFFER_STORE_LWIP_POOL ||                                                  \
     CHIP_SYSTEM_PACKETBUFFER_STORE == CHIP_SYSTEM_PACKETBUFFER_STORE_LWIP_CUSTOM
 
-    lPacket = static_cast<PacketBuffer *>(pbuf_alloc(PBUF_RAW, static_cast<uint16_t>(lBlockSize), PBUF_POOL));
+    lPacket = static_cast<PacketBuffer *>(pbuf_alloc(PBUF_RAW, static_cast<uint16_t>(lAllocSize), PBUF_POOL));
 
     SYSTEM_STATS_UPDATE_LWIP_PBUF_COUNTS();
 
diff --git a/src/system/tests/TestSystemPacketBuffer.cpp b/src/system/tests/TestSystemPacketBuffer.cpp
index e2c199c34f966f..aaa35b214ac463 100644
--- a/src/system/tests/TestSystemPacketBuffer.cpp
+++ b/src/system/tests/TestSystemPacketBuffer.cpp
@@ -191,7 +191,7 @@ class PacketBufferTest
     std::vector<PacketBufferHandle> handles;
 };
 
-const uint16_t sTestReservedSizes[] = { 0, 10, 128, 1536, PacketBufferTest::kBlockSize };
+const uint16_t sTestReservedSizes[] = { 0, 10, 128, 1536, PacketBuffer::kMaxSizeWithoutReserve, PacketBufferTest::kBlockSize };
 const uint16_t sTestLengths[]       = { 0, 1, 10, 128, PacketBufferTest::kBlockSize, UINT16_MAX };
 
 PacketBufferTest::TestContext sContext = {