From 5d3695b2f986b83bde389761d9f115325f08ebdb Mon Sep 17 00:00:00 2001
From: Sagar Dhawan <sagar_dhawan@apple.com>
Date: Thu, 22 Jul 2021 14:49:10 -0700
Subject: [PATCH] [Darwin] Fix incorrect Thread panID generation (#8562)

* [Darwin] Fix incorrect Thread panID generation

* Fix restyled issue

Co-authored-by: Boris Zbarsky <bzbarsky@apple.com>
---
 .../CHIP/CHIPThreadOperationalDataset.h       |  6 ++++
 .../CHIP/CHIPThreadOperationalDataset.mm      | 35 ++++++++++++++++++-
 .../CHIPThreadOperationalDatasetTests.mm      |  9 +++++
 3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/src/darwin/Framework/CHIP/CHIPThreadOperationalDataset.h b/src/darwin/Framework/CHIP/CHIPThreadOperationalDataset.h
index fab019eb169c98..a3e5de59cadcf4 100644
--- a/src/darwin/Framework/CHIP/CHIPThreadOperationalDataset.h
+++ b/src/darwin/Framework/CHIP/CHIPThreadOperationalDataset.h
@@ -73,6 +73,12 @@ extern size_t const CHIPSizeThreadPSKc;
                                      channel:(uint16_t)channel
                                        panID:(NSData *)panID;
 
+/**
+ *  Create a Thread Operational Dataset object with a RCP formatted active operational dataset.
+ *  This initializer will return nil if the input data cannot be parsed correctly
+ */
+- (nullable instancetype)initWithData:(NSData *)data;
+
 /**
  * Get the underlying data that represents the Thread Active Operational Dataset
  */
diff --git a/src/darwin/Framework/CHIP/CHIPThreadOperationalDataset.mm b/src/darwin/Framework/CHIP/CHIPThreadOperationalDataset.mm
index b48dcb0dc647bb..0f48e2ed37ce42 100644
--- a/src/darwin/Framework/CHIP/CHIPThreadOperationalDataset.mm
+++ b/src/darwin/Framework/CHIP/CHIPThreadOperationalDataset.mm
@@ -96,7 +96,8 @@ - (BOOL)_populateCppOperationalDataset
     if (valuePtr == nullptr) {
         return NO;
     }
-    _cppThreadOperationalDataset.SetPanId(*valuePtr);
+    // The underlying CPP class assumes Big Endianness for the panID
+    _cppThreadOperationalDataset.SetPanId(CFSwapInt16HostToBig(*valuePtr));
 
     return YES;
 }
@@ -110,6 +111,38 @@ - (BOOL)_checkDataLength:(NSData *)data expectedLength:(size_t)expectedLength
     return YES;
 }
 
+- (nullable instancetype)initWithData:(NSData *)data
+{
+    chip::ByteSpan span = chip::ByteSpan((uint8_t *) data.bytes, data.length);
+    auto dataset = chip::Thread::OperationalDataset();
+    CHIP_ERROR error = dataset.Init(span);
+    if (error != CHIP_NO_ERROR) {
+        CHIP_LOG_ERROR("Failed to parse data, cannot construct Operational Dataset. %d", error);
+        return nil;
+    }
+    // len+1 for null termination
+    char networkName[CHIPSizeThreadNetworkName + 1];
+    uint8_t pskc[CHIPSizeThreadPSKc];
+    uint8_t extendedPANID[CHIPSizeThreadExtendedPanId];
+    uint8_t masterKey[CHIPSizeThreadMasterKey];
+    uint16_t panID;
+    uint16_t channel;
+    dataset.GetNetworkName(networkName);
+    dataset.GetExtendedPanId(extendedPANID);
+    dataset.GetMasterKey(masterKey);
+    dataset.GetPSKc(pskc);
+    dataset.GetPanId(panID);
+    dataset.GetChannel(channel);
+    panID = CFSwapInt16BigToHost(panID);
+
+    return [self initWithNetworkName:[NSString stringWithUTF8String:networkName]
+                       extendedPANID:[NSData dataWithBytes:extendedPANID length:CHIPSizeThreadExtendedPanId]
+                           masterKey:[NSData dataWithBytes:masterKey length:CHIPSizeThreadMasterKey]
+                                PSKc:[NSData dataWithBytes:pskc length:CHIPSizeThreadPSKc]
+                             channel:channel
+                               panID:[NSData dataWithBytes:&panID length:sizeof(uint16_t)]];
+}
+
 - (NSData *)asData
 {
     chip::ByteSpan span = _cppThreadOperationalDataset.AsByteSpan();
diff --git a/src/darwin/Framework/CHIPTests/CHIPThreadOperationalDatasetTests.mm b/src/darwin/Framework/CHIPTests/CHIPThreadOperationalDatasetTests.mm
index 1f1b2390308a64..614dd319e1731d 100644
--- a/src/darwin/Framework/CHIPTests/CHIPThreadOperationalDatasetTests.mm
+++ b/src/darwin/Framework/CHIPTests/CHIPThreadOperationalDatasetTests.mm
@@ -46,6 +46,15 @@ - (void)testThreadOperationalDataset
     XCTAssertNotNil(dataset);
     NSData * data = [dataset asData];
     XCTAssertNotNil(data);
+
+    CHIPThreadOperationalDataset * reconstructed = [[CHIPThreadOperationalDataset alloc] initWithData:data];
+    XCTAssertNotNil(reconstructed);
+    XCTAssertEqualObjects(reconstructed.networkName, dataset.networkName);
+    XCTAssertEqualObjects(reconstructed.panID, dataset.panID);
+    XCTAssertEqualObjects(reconstructed.masterKey, dataset.masterKey);
+    XCTAssertEqualObjects(reconstructed.PSKc, dataset.PSKc);
+    XCTAssertEqualObjects(reconstructed.extendedPANID, dataset.extendedPANID);
+    XCTAssertEqual(reconstructed.channel, dataset.channel);
 }
 
 - (void)testThreadOperationalDatasetInvalid