Be a bit more verbose in circuit test reports to more clearly track current and upstream hop in graph traversal history.

controller/SqliteNetworkController.cpp

@@ -1881,7 +1881,7 @@ void SqliteNetworkController::_circuitTestCallback(ZT_Node *node,ZT_CircuitTest
 	Utils::snprintf(tmp,sizeof(tmp),ZT_PATH_SEPARATOR_S"%.16llx_%.16llx",test->timestamp,test->testId);
 	reportSavePath.append(tmp);
 	OSUtils::mkdir(reportSavePath);
-	Utils::snprintf(tmp,sizeof(tmp),ZT_PATH_SEPARATOR_S"%.10llx",report->address);
+	Utils::snprintf(tmp,sizeof(tmp),ZT_PATH_SEPARATOR_S"%.10llx_%.10llx",report->upstream,report->current);
 	reportSavePath.append(tmp);
 
 	{
@@ -1891,7 +1891,8 @@ void SqliteNetworkController::_circuitTestCallback(ZT_Node *node,ZT_CircuitTest
 			return;
 		fseek(f,0,SEEK_END);
 		fprintf(f,"%s{\n"
-			"\t\"address\": \"%.10llx\","ZT_EOL_S
+			"\t\"current\": \"%.10llx\","ZT_EOL_S
+			"\t\"upstream\": \"%.10llx\","ZT_EOL_S
 			"\t\"testId\": \"%.16llx\","ZT_EOL_S
 			"\t\"timestamp\": %llu,"ZT_EOL_S
 			"\t\"receivedTimestamp\": %llu,"ZT_EOL_S
@@ -1911,7 +1912,8 @@ void SqliteNetworkController::_circuitTestCallback(ZT_Node *node,ZT_CircuitTest
 			"\t\"receivedFromRemoteAddress\": \"%s\""ZT_EOL_S
 			"}",
 			((ftell(f) > 0) ? ",\n" : ""),
-			(unsigned long long)report->address,
+			(unsigned long long)report->current,
+			(unsigned long long)report->upstream,
 			(unsigned long long)test->testId,
 			(unsigned long long)report->timestamp,
 			(unsigned long long)now,

include/ZeroTierOne.h

@@ -733,9 +733,14 @@ typedef struct {
  */
 typedef struct {
 	/**
-	 * Sender of report
+	 * Sender of report (current hop)
 	 */
-	uint64_t address;
+	uint64_t current;
+
+	/**
+	 * Previous hop
+	 */
+	uint64_t upstream;
 
 	/**
 	 * 64-bit test ID

node/IncomingPacket.cpp

@@ -993,6 +993,7 @@ bool IncomingPacket::_doCIRCUIT_TEST(const RuntimeEnvironment *RR,const SharedPt
 			outp.append((uint16_t)0); // error code, currently unused
 			outp.append((uint64_t)0); // flags, currently unused
 			outp.append((uint64_t)packetId());
+			peer->address().appendTo(outp);
 			outp.append((uint8_t)hops());
 			_localAddress.serialize(outp);
 			_remoteAddress.serialize(outp);
@@ -1039,13 +1040,14 @@ bool IncomingPacket::_doCIRCUIT_TEST_REPORT(const RuntimeEnvironment *RR,const S
 		ZT_CircuitTestReport report;
 		memset(&report,0,sizeof(report));
 
-		report.address = peer->address().toInt();
+		report.current = peer->address().toInt();
+		report.upstream = Address(field(ZT_PACKET_IDX_PAYLOAD + 52,ZT_ADDRESS_LENGTH),ZT_ADDRESS_LENGTH).toInt();
 		report.testId = at<uint64_t>(ZT_PACKET_IDX_PAYLOAD + 8);
 		report.timestamp = at<uint64_t>(ZT_PACKET_IDX_PAYLOAD);
 		report.remoteTimestamp = at<uint64_t>(ZT_PACKET_IDX_PAYLOAD + 16);
 		report.sourcePacketId = at<uint64_t>(ZT_PACKET_IDX_PAYLOAD + 44);
 		report.flags = at<uint64_t>(ZT_PACKET_IDX_PAYLOAD + 36);
-		report.sourcePacketHopCount = (*this)[ZT_PACKET_IDX_PAYLOAD + 52];
+		report.sourcePacketHopCount = (*this)[ZT_PACKET_IDX_PAYLOAD + 57]; // end of fixed length headers: 58
 		report.errorCode = at<uint16_t>(ZT_PACKET_IDX_PAYLOAD + 34);
 		report.vendor = (enum ZT_Vendor)((*this)[ZT_PACKET_IDX_PAYLOAD + 24]);
 		report.protocolVersion = (*this)[ZT_PACKET_IDX_PAYLOAD + 25];
@@ -1055,10 +1057,10 @@ bool IncomingPacket::_doCIRCUIT_TEST_REPORT(const RuntimeEnvironment *RR,const S
 		report.platform = (enum ZT_Platform)at<uint16_t>(ZT_PACKET_IDX_PAYLOAD + 30);
 		report.architecture = (enum ZT_Architecture)at<uint16_t>(ZT_PACKET_IDX_PAYLOAD + 32);
 
-		const unsigned int receivedOnLocalAddressLen = reinterpret_cast<InetAddress *>(&(report.receivedOnLocalAddress))->deserialize(*this,ZT_PACKET_IDX_PAYLOAD + 53);
-		const unsigned int receivedFromRemoteAddressLen = reinterpret_cast<InetAddress *>(&(report.receivedFromRemoteAddress))->deserialize(*this,ZT_PACKET_IDX_PAYLOAD + 53 + receivedOnLocalAddressLen);
+		const unsigned int receivedOnLocalAddressLen = reinterpret_cast<InetAddress *>(&(report.receivedOnLocalAddress))->deserialize(*this,ZT_PACKET_IDX_PAYLOAD + 58);
+		const unsigned int receivedFromRemoteAddressLen = reinterpret_cast<InetAddress *>(&(report.receivedFromRemoteAddress))->deserialize(*this,ZT_PACKET_IDX_PAYLOAD + 58 + receivedOnLocalAddressLen);
 
-		unsigned int nhptr = ZT_PACKET_IDX_PAYLOAD + 53 + receivedOnLocalAddressLen + receivedFromRemoteAddressLen;
+		unsigned int nhptr = ZT_PACKET_IDX_PAYLOAD + 58 + receivedOnLocalAddressLen + receivedFromRemoteAddressLen;
 		nhptr += at<uint16_t>(nhptr) + 2; // add "additional field" length, which right now will be zero
 
 		report.nextHopCount = (*this)[nhptr++];

node/Packet.hpp

@@ -1031,6 +1031,7 @@ public:
 		 *   <[2] 16-bit error code (set to 0, currently unused)>
 		 *   <[8] 64-bit report flags (set to 0, currently unused)>
 		 *   <[8] 64-bit source packet ID>
+		 *   <[5] upstream ZeroTier address from which test was received>
 		 *   <[1] 8-bit source packet hop count (ZeroTier hop count)>
 		 *   <[...] local wire address on which packet was received>
 		 *   <[...] remote wire address from which packet was received>