Reduce the size of FabricInfo by reordering some members. (#28278)
* Reduce the size of FabricInfo by reordering some members.
On 32-bit systems this changes the size from 152 bytes to 144 bytes.
On 64-bit systems this changes the size from 168 bytes to 152 bytes.
* Address review comment.
* Remove static asserts, because offsetof is not happy on FabricInfo.
diff --git a/src/credentials/FabricTable.h b/src/credentials/FabricTable.h
index 60cd54d..2610298 100644
--- a/src/credentials/FabricTable.h
+++ b/src/credentials/FabricTable.h
@@ -220,18 +220,27 @@
return TLV::EstimateStructOverhead(sizeof(uint16_t), Crypto::P256SerializedKeypair::Capacity());
}
- NodeId mNodeId = kUndefinedNodeId;
- FabricId mFabricId = kUndefinedFabricId;
- FabricIndex mFabricIndex = kUndefinedFabricIndex;
+ NodeId mNodeId = kUndefinedNodeId;
+ FabricId mFabricId = kUndefinedFabricId;
// We cache the compressed fabric id since it's used so often and costly to get.
CompressedFabricId mCompressedFabricId = kUndefinedCompressedFabricId;
// We cache the root public key since it's used so often and costly to get.
Crypto::P256PublicKey mRootPublicKey;
- VendorId mVendorId = VendorId::NotSpecified;
+ // mFabricLabel is 33 bytes, so ends on a 1 mod 4 byte boundary.
char mFabricLabel[kFabricLabelMaxLengthInBytes + 1] = { '\0' };
- mutable Crypto::P256Keypair * mOperationalKey = nullptr;
- bool mHasExternallyOwnedOperationalKey = false;
+
+ // mFabricIndex, mVendorId, mHasExternallyOwnedOperationalKey are 4 bytes
+ // and do not end up with any padding if they come after the 33-byte
+ // mFabricLabel, so end on a 1 mod 4 byte boundary.
+ FabricIndex mFabricIndex = kUndefinedFabricIndex;
+ VendorId mVendorId = VendorId::NotSpecified;
+ bool mHasExternallyOwnedOperationalKey = false;
+
+ // 3 bytes of padding here, since mOperationalKey needs to be void*-aligned,
+ // so has to be at a 0 mod 4 byte location.
+
+ mutable Crypto::P256Keypair * mOperationalKey = nullptr;
CHIP_ERROR CommitToStorage(PersistentStorageDelegate * storage) const;
CHIP_ERROR LoadFromStorage(PersistentStorageDelegate * storage, FabricIndex newFabricIndex, const ByteSpan & rcac,
