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Round-trip time calculation based on Jacobson’s algorithm
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Fixes #26
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@nxrighthere
nxrighthere authored Nov 9, 2018
1 parent ad27538 commit e5f8bc0
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Showing 2 changed files with 35 additions and 24 deletions.
4 changes: 2 additions & 2 deletions Source/Managed/ENet.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -738,7 +738,7 @@ public static class Library {
public const uint timeoutLimit = 32;
public const uint timeoutMinimum = 5000;
public const uint timeoutMaximum = 30000;
public const uint version = (2 << 16) | (1 << 8) | (2);
public const uint version = (2 << 16) | (1 << 8) | (3);

public static bool Initialize() {
return Native.enet_initialize() == 0;
Expand Down Expand Up @@ -922,4 +922,4 @@ internal static class Native {
[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
internal static extern void enet_peer_reset(IntPtr peer);
}
}
}
55 changes: 33 additions & 22 deletions Source/Native/enet.h
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Original file line number Diff line number Diff line change
Expand Up @@ -35,7 +35,7 @@

#define ENET_VERSION_MAJOR 2
#define ENET_VERSION_MINOR 1
#define ENET_VERSION_PATCH 2
#define ENET_VERSION_PATCH 3
#define ENET_VERSION_CREATE(major, minor, patch) (((major) << 16) | ((minor) << 8) | (patch))
#define ENET_VERSION_GET_MAJOR(version) (((version) >> 16) & 0xFF)
#define ENET_VERSION_GET_MINOR(version) (((version) >> 8) & 0xFF)
Expand All @@ -45,10 +45,13 @@
#define ENET_TIME_OVERFLOW 86400000
#define ENET_TIME_LESS(a, b) ((a) - (b) >= ENET_TIME_OVERFLOW)
#define ENET_TIME_GREATER(a, b) ((b) - (a) >= ENET_TIME_OVERFLOW)
#define ENET_TIME_LESS_EQUAL(a, b) (! ENET_TIME_GREATER (a, b))
#define ENET_TIME_GREATER_EQUAL(a, b) (! ENET_TIME_LESS (a, b))
#define ENET_TIME_LESS_EQUAL(a, b) (! ENET_TIME_GREATER(a, b))
#define ENET_TIME_GREATER_EQUAL(a, b) (! ENET_TIME_LESS(a, b))
#define ENET_TIME_DIFFERENCE(a, b) ((a) - (b) >= ENET_TIME_OVERFLOW ? (b) - (a) : (a) - (b))

#define ENET_SRTT_INITIAL 1.0
#define ENET_SRTT_PARA_G 0.125

// =======================================================================//
// !
// ! System differences
Expand Down Expand Up @@ -200,9 +203,9 @@ extern "C" {
// =======================================================================//

typedef uint8_t enet_uint8;
typedef uint16_t enet_uint16;
typedef uint32_t enet_uint32;
typedef uint64_t enet_uint64;
typedef uint16_t enet_uint16;
typedef uint32_t enet_uint32;
typedef uint64_t enet_uint64;

typedef enet_uint32 ENetVersion;

Expand Down Expand Up @@ -448,7 +451,7 @@ extern "C" {
ENET_SOCKOPT_SNDTIMEO = 7,
ENET_SOCKOPT_ERROR = 8,
ENET_SOCKOPT_NODELAY = 9,
ENET_SOCKOPT_IPV6_V6ONLY = 10,
ENET_SOCKOPT_IPV6_V6ONLY = 10
} ENetSocketOption;

typedef enum _ENetSocketShutdown {
Expand All @@ -470,7 +473,7 @@ extern "C" {
ENET_PACKET_FLAG_UNSEQUENCED = (1 << 1),
ENET_PACKET_FLAG_NO_ALLOCATE = (1 << 2),
ENET_PACKET_FLAG_UNRELIABLE_FRAGMENT = (1 << 3),
ENET_PACKET_FLAG_SENT = (1 << 8),
ENET_PACKET_FLAG_SENT = (1 << 8)
} ENetPacketFlag;

typedef void (ENET_CALLBACK *ENetPacketFreeCallback) (void *);
Expand Down Expand Up @@ -611,6 +614,7 @@ extern "C" {
enet_uint32 timeoutLimit;
enet_uint32 timeoutMinimum;
enet_uint32 timeoutMaximum;
enet_uint32 smoothedRoundTripTime;
enet_uint32 lastRoundTripTime;
enet_uint32 lowestRoundTripTime;
enet_uint32 lastRoundTripTimeVariance;
Expand Down Expand Up @@ -684,7 +688,7 @@ extern "C" {
ENET_EVENT_TYPE_CONNECT = 1,
ENET_EVENT_TYPE_DISCONNECT = 2,
ENET_EVENT_TYPE_RECEIVE = 3,
ENET_EVENT_TYPE_DISCONNECT_TIMEOUT = 4,
ENET_EVENT_TYPE_DISCONNECT_TIMEOUT = 4
} ENetEventType;

typedef struct _ENetEvent {
Expand Down Expand Up @@ -2077,16 +2081,22 @@ extern "C" {
peer->earliestTimeout = 0;
roundTripTime = ENET_TIME_DIFFERENCE(host->serviceTime, receivedSentTime);

enet_peer_throttle(peer, roundTripTime);
if (peer->smoothedRoundTripTime == 0) {
peer->smoothedRoundTripTime = (enet_uint32)((1 - ENET_SRTT_PARA_G) * ENET_SRTT_INITIAL + ENET_SRTT_PARA_G * roundTripTime);
} else {
peer->smoothedRoundTripTime = (enet_uint32)((1 - ENET_SRTT_PARA_G) * peer->smoothedRoundTripTime + ENET_SRTT_PARA_G * roundTripTime);
}

enet_peer_throttle(peer, peer->smoothedRoundTripTime);

peer->roundTripTimeVariance -= peer->roundTripTimeVariance / 4;

if (roundTripTime >= peer->roundTripTime) {
peer->roundTripTime += (roundTripTime - peer->roundTripTime) / 8;
peer->roundTripTimeVariance += (roundTripTime - peer->roundTripTime) / 4;
if (peer->smoothedRoundTripTime >= peer->roundTripTime) {
peer->roundTripTime += (peer->smoothedRoundTripTime - peer->roundTripTime) / 8;
peer->roundTripTimeVariance += (peer->smoothedRoundTripTime - peer->roundTripTime) / 4;
} else {
peer->roundTripTime -= (peer->roundTripTime - roundTripTime) / 8;
peer->roundTripTimeVariance += (peer->roundTripTime - roundTripTime) / 4;
peer->roundTripTime -= (peer->roundTripTime - peer->smoothedRoundTripTime) / 8;
peer->roundTripTimeVariance += (peer->roundTripTime - peer->smoothedRoundTripTime) / 4;
}

if (peer->roundTripTime < peer->lowestRoundTripTime) {
Expand Down Expand Up @@ -2245,9 +2255,9 @@ extern "C" {

if (peer->state == ENET_PEER_STATE_DISCONNECTED ||
peer->state == ENET_PEER_STATE_ZOMBIE ||
((!in6_equal(host->receivedAddress.host , peer->address.host) ||
((!in6_equal(host->receivedAddress.host, peer->address.host) ||
host->receivedAddress.port != peer->address.port) &&
1 /* No broadcast in IPv6 - !in6_equal(peer->address.host , ENET_HOST_BROADCAST) */) ||
1 /* No broadcast in IPv6 - !in6_equal(peer->address.host, ENET_HOST_BROADCAST) */) ||
(peer->outgoingPeerID < ENET_PROTOCOL_MAXIMUM_PEER_ID &&
sessionID != peer->incomingSessionID)
) {
Expand Down Expand Up @@ -2881,12 +2891,12 @@ extern "C" {
#ifdef ENET_DEBUG
printf(
"peer %u: %f%%+-%f%% packet loss, %u+-%u ms round trip time, %f%% throttle, %u/%u outgoing, %u/%u incoming\n", currentPeer->incomingPeerID,
currentPeer->packetLoss / (float) ENET_PEER_PACKET_LOSS_SCALE,
currentPeer->packetLossVariance / (float) ENET_PEER_PACKET_LOSS_SCALE, currentPeer->roundTripTime, currentPeer->roundTripTimeVariance,
currentPeer->packetThrottle / (float) ENET_PEER_PACKET_THROTTLE_SCALE,
currentPeer->packetLoss / (float)ENET_PEER_PACKET_LOSS_SCALE,
currentPeer->packetLossVariance / (float)ENET_PEER_PACKET_LOSS_SCALE, currentPeer->roundTripTime, currentPeer->roundTripTimeVariance,
currentPeer->packetThrottle / (float)ENET_PEER_PACKET_THROTTLE_SCALE,
enet_list_size(&currentPeer->outgoingReliableCommands),
enet_list_size(&currentPeer->outgoingUnreliableCommands),
currentPeer->channels != NULL ? enet_list_size( &currentPeer->channels->incomingReliableCommands) : 0,
currentPeer->channels != NULL ? enet_list_size(&currentPeer->channels->incomingReliableCommands) : 0,
currentPeer->channels != NULL ? enet_list_size(&currentPeer->channels->incomingUnreliableCommands) : 0
);
#endif
Expand Down Expand Up @@ -3425,6 +3435,7 @@ extern "C" {
peer->timeoutLimit = ENET_PEER_TIMEOUT_LIMIT;
peer->timeoutMinimum = ENET_PEER_TIMEOUT_MINIMUM;
peer->timeoutMaximum = ENET_PEER_TIMEOUT_MAXIMUM;
peer->smoothedRoundTripTime = 0;
peer->lastRoundTripTime = ENET_PEER_DEFAULT_ROUND_TRIP_TIME;
peer->lowestRoundTripTime = ENET_PEER_DEFAULT_ROUND_TRIP_TIME;
peer->lastRoundTripTimeVariance = 0;
Expand Down Expand Up @@ -4544,7 +4555,7 @@ extern "C" {
}

enet_uint32 enet_peer_get_rtt(ENetPeer *peer) {
return peer->roundTripTime;
return peer->smoothedRoundTripTime;
}

enet_uint32 enet_peer_get_lastsendtime(ENetPeer *peer) {
Expand Down

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