ref: 935b2d59612ac7945a17b8025848fe1e3c94fc1f
dir: /Engine/src/enet/peer.c/
/**
@file peer.c
@brief ENet peer management functions
*/
#define ENET_BUILDING_LIB 1
#include "memory.h"
#include "enet.h"
/** @defgroup peer ENet peer functions
@{
*/
/** Configures throttle parameter for a peer.
Unreliable packets are dropped by ENet in response to the varying conditions
of the Internet connection to the peer. The throttle represents a probability
that an unreliable packet should not be dropped and thus sent by ENet to the peer.
The lowest mean round trip time from the sending of a reliable packet to the
receipt of its acknowledgement is measured over an amount of time specified by
the interval parameter in milliseconds. If a measured round trip time happens to
be significantly less than the mean round trip time measured over the interval,
then the throttle probability is increased to allow more traffic by an amount
specified in the acceleration parameter, which is a ratio to the ENET_PEER_PACKET_THROTTLE_SCALE
constant. If a measured round trip time happens to be significantly greater than
the mean round trip time measured over the interval, then the throttle probability
is decreased to limit traffic by an amount specified in the deceleration parameter, which
is a ratio to the ENET_PEER_PACKET_THROTTLE_SCALE constant. When the throttle has
a value of ENET_PEER_PACKET_THROTTLE_SCALE, on unreliable packets are dropped by
ENet, and so 100% of all unreliable packets will be sent. When the throttle has a
value of 0, all unreliable packets are dropped by ENet, and so 0% of all unreliable
packets will be sent. Intermediate values for the throttle represent intermediate
probabilities between 0% and 100% of unreliable packets being sent. The bandwidth
limits of the local and foreign hosts are taken into account to determine a
sensible limit for the throttle probability above which it should not raise even in
the best of conditions.
@param peer peer to configure
@param interval interval, in milliseconds, over which to measure lowest mean RTT; the default value is ENET_PEER_PACKET_THROTTLE_INTERVAL.
@param acceleration rate at which to increase the throttle probability as mean RTT declines
@param deceleration rate at which to decrease the throttle probability as mean RTT increases
*/
void
enet_peer_throttle_configure (ENetPeer * peer, enet_uint32 interval, enet_uint32 acceleration, enet_uint32 deceleration)
{
ENetProtocol command;
peer -> packetThrottleInterval = interval;
peer -> packetThrottleAcceleration = acceleration;
peer -> packetThrottleDeceleration = deceleration;
command.header.command = ENET_PROTOCOL_COMMAND_THROTTLE_CONFIGURE;
command.header.channelID = 0xFF;
command.header.flags = 0;
command.header.commandLength = sizeof (ENetProtocolThrottleConfigure);
command.throttleConfigure.packetThrottleInterval = ENET_HOST_TO_NET_32 (interval);
command.throttleConfigure.packetThrottleAcceleration = ENET_HOST_TO_NET_32 (acceleration);
command.throttleConfigure.packetThrottleDeceleration = ENET_HOST_TO_NET_32 (deceleration);
enet_peer_queue_outgoing_command (peer, & command, NULL, 0, 0);
}
int
enet_peer_throttle (ENetPeer * peer, enet_uint32 rtt)
{
if (peer -> lastRoundTripTime <= peer -> lastRoundTripTimeVariance)
{
peer -> packetThrottle = peer -> packetThrottleLimit;
}
else
if (rtt < peer -> lastRoundTripTime)
{
peer -> packetThrottle += peer -> packetThrottleAcceleration;
if (peer -> packetThrottle > peer -> packetThrottleLimit)
peer -> packetThrottle = peer -> packetThrottleLimit;
return 1;
}
else
if (rtt > peer -> lastRoundTripTime + 2 * peer -> lastRoundTripTimeVariance)
{
if (peer -> packetThrottle > peer -> packetThrottleDeceleration)
peer -> packetThrottle -= peer -> packetThrottleDeceleration;
else
peer -> packetThrottle = 0;
return -1;
}
return 0;
}
/** Queues a packet to be sent.
@param peer destination for the packet
@param channelID channel on which to send
@param packet packet to send
@retval 0 on success
@retval < 0 on failure
*/
int
enet_peer_send (ENetPeer * peer, enet_uint8 channelID, ENetPacket * packet)
{
ENetChannel * channel = & peer -> channels [channelID];
ENetProtocol command;
size_t fragmentLength;
if (peer -> state != ENET_PEER_STATE_CONNECTED)
return -1;
fragmentLength = peer -> mtu - sizeof (ENetProtocolHeader) - sizeof (ENetProtocolSendFragment);
if (packet -> dataLength > fragmentLength)
{
enet_uint32 fragmentCount = ENET_HOST_TO_NET_32 ((packet -> dataLength + fragmentLength - 1) / fragmentLength),
startSequenceNumber = ENET_HOST_TO_NET_32 (channel -> outgoingReliableSequenceNumber + 1),
fragmentNumber,
fragmentOffset;
packet -> flags |= ENET_PACKET_FLAG_RELIABLE;
for (fragmentNumber = 0,
fragmentOffset = 0;
fragmentOffset < packet -> dataLength;
++ fragmentNumber,
fragmentOffset += fragmentLength)
{
command.header.command = ENET_PROTOCOL_COMMAND_SEND_FRAGMENT;
command.header.channelID = channelID;
command.header.flags = ENET_PROTOCOL_FLAG_ACKNOWLEDGE;
command.header.commandLength = sizeof (ENetProtocolSendFragment);
command.sendFragment.startSequenceNumber = startSequenceNumber;
command.sendFragment.fragmentCount = fragmentCount;
command.sendFragment.fragmentNumber = ENET_HOST_TO_NET_32 (fragmentNumber);
command.sendFragment.totalLength = ENET_HOST_TO_NET_32 (packet -> dataLength);
command.sendFragment.fragmentOffset = ENET_NET_TO_HOST_32 (fragmentOffset);
if (packet -> dataLength - fragmentOffset < fragmentLength)
fragmentLength = packet -> dataLength - fragmentOffset;
enet_peer_queue_outgoing_command (peer, & command, packet, fragmentOffset, fragmentLength);
}
return 0;
}
command.header.channelID = channelID;
if (packet -> flags & ENET_PACKET_FLAG_RELIABLE)
{
command.header.command = ENET_PROTOCOL_COMMAND_SEND_RELIABLE;
command.header.flags = ENET_PROTOCOL_FLAG_ACKNOWLEDGE;
command.header.commandLength = sizeof (ENetProtocolSendReliable);
}
else
{
command.header.command = ENET_PROTOCOL_COMMAND_SEND_UNRELIABLE;
command.header.flags = 0;
command.header.commandLength = sizeof (ENetProtocolSendUnreliable);
command.sendUnreliable.unreliableSequenceNumber = ENET_HOST_TO_NET_32 (channel -> outgoingUnreliableSequenceNumber + 1);
}
enet_peer_queue_outgoing_command (peer, & command, packet, 0, packet -> dataLength);
return 0;
}
/** Attempts to dequeue any incoming queued packet.
@param peer peer to dequeue packets from
@param channelID channel on which to receive
@returns a pointer to the packet, or NULL if there are no available incoming queued packets
*/
ENetPacket *
enet_peer_receive (ENetPeer * peer, enet_uint8 channelID)
{
ENetChannel * channel = & peer -> channels [channelID];
ENetIncomingCommand * incomingCommand = NULL;
ENetPacket * packet;
if (enet_list_empty (& channel -> incomingUnreliableCommands) == 0)
{
incomingCommand = (ENetIncomingCommand *) enet_list_front (& channel -> incomingUnreliableCommands);
if (incomingCommand -> reliableSequenceNumber > channel -> incomingReliableSequenceNumber)
incomingCommand = NULL;
else
channel -> incomingUnreliableSequenceNumber = incomingCommand -> unreliableSequenceNumber;
}
if (incomingCommand == NULL &&
enet_list_empty (& channel -> incomingReliableCommands) == 0)
{
do
{
incomingCommand = (ENetIncomingCommand *) enet_list_front (& channel -> incomingReliableCommands);
if (incomingCommand -> fragmentsRemaining > 0 ||
incomingCommand -> reliableSequenceNumber > channel -> incomingReliableSequenceNumber + 1)
return NULL;
if (incomingCommand -> reliableSequenceNumber <= channel -> incomingReliableSequenceNumber)
{
-- incomingCommand -> packet -> referenceCount;
if (incomingCommand -> packet -> referenceCount == 0)
enet_packet_destroy (incomingCommand -> packet);
if (incomingCommand -> fragments != NULL)
enet_free (incomingCommand -> fragments);
enet_list_remove (& incomingCommand -> incomingCommandList);
enet_free (incomingCommand);
incomingCommand = NULL;
}
} while (incomingCommand == NULL &&
enet_list_empty (& channel -> incomingReliableCommands) == 0);
if (incomingCommand == NULL)
return NULL;
channel -> incomingReliableSequenceNumber = incomingCommand -> reliableSequenceNumber;
if (incomingCommand -> fragmentCount > 0)
channel -> incomingReliableSequenceNumber += incomingCommand -> fragmentCount - 1;
}
if (incomingCommand == NULL)
return NULL;
enet_list_remove (& incomingCommand -> incomingCommandList);
packet = incomingCommand -> packet;
-- packet -> referenceCount;
if (incomingCommand -> fragments != NULL)
enet_free (incomingCommand -> fragments);
enet_free (incomingCommand);
return packet;
}
static void
enet_peer_reset_outgoing_commands (ENetList * queue)
{
ENetOutgoingCommand * outgoingCommand;
while (enet_list_empty (queue) == 0)
{
outgoingCommand = (ENetOutgoingCommand *) enet_list_remove (enet_list_begin (queue));
if (outgoingCommand -> packet != NULL)
{
-- outgoingCommand -> packet -> referenceCount;
if (outgoingCommand -> packet -> referenceCount == 0)
enet_packet_destroy (outgoingCommand -> packet);
}
enet_free (outgoingCommand);
}
}
static void
enet_peer_reset_incoming_commands (ENetList * queue)
{
ENetIncomingCommand * incomingCommand;
while (enet_list_empty (queue) == 0)
{
incomingCommand = (ENetIncomingCommand *) enet_list_remove (enet_list_begin (queue));
if (incomingCommand -> packet != NULL)
{
-- incomingCommand -> packet -> referenceCount;
if (incomingCommand -> packet -> referenceCount == 0)
enet_packet_destroy (incomingCommand -> packet);
}
enet_free (incomingCommand);
}
}
void
enet_peer_reset_queues (ENetPeer * peer)
{
ENetChannel * channel;
while (enet_list_empty (& peer -> acknowledgements) == 0)
enet_free (enet_list_remove (enet_list_begin (& peer -> acknowledgements)));
enet_peer_reset_outgoing_commands (& peer -> sentReliableCommands);
enet_peer_reset_outgoing_commands (& peer -> sentUnreliableCommands);
enet_peer_reset_outgoing_commands (& peer -> outgoingReliableCommands);
enet_peer_reset_outgoing_commands (& peer -> outgoingUnreliableCommands);
if (peer -> channels != NULL && peer -> channelCount > 0)
{
for (channel = peer -> channels;
channel < & peer -> channels [peer -> channelCount];
++ channel)
{
enet_peer_reset_incoming_commands (& channel -> incomingReliableCommands);
enet_peer_reset_incoming_commands (& channel -> incomingUnreliableCommands);
}
enet_free (peer -> channels);
}
peer -> channels = NULL;
peer -> channelCount = 0;
}
/** Forcefully disconnects a peer.
@param peer peer to forcefully disconnect
@remarks The foreign host represented by the peer is not notified of the disconnection and will timeout
on its connection to the local host.
*/
void
enet_peer_reset (ENetPeer * peer)
{
peer -> outgoingPeerID = 0xFFFF;
peer -> challenge = 0;
peer -> address.host = ENET_HOST_ANY;
peer -> address.port = 0;
peer -> state = ENET_PEER_STATE_DISCONNECTED;
peer -> incomingBandwidth = 0;
peer -> outgoingBandwidth = 0;
peer -> incomingBandwidthThrottleEpoch = 0;
peer -> outgoingBandwidthThrottleEpoch = 0;
peer -> incomingDataTotal = 0;
peer -> outgoingDataTotal = 0;
peer -> lastSendTime = 0;
peer -> lastReceiveTime = 0;
peer -> nextTimeout = 0;
peer -> packetLossEpoch = 0;
peer -> packetsSent = 0;
peer -> packetsLost = 0;
peer -> packetLoss = 0;
peer -> packetLossVariance = 0;
peer -> packetThrottle = ENET_PEER_DEFAULT_PACKET_THROTTLE;
peer -> packetThrottleLimit = ENET_PEER_PACKET_THROTTLE_SCALE;
peer -> packetThrottleCounter = 0;
peer -> packetThrottleEpoch = 0;
peer -> packetThrottleAcceleration = ENET_PEER_PACKET_THROTTLE_ACCELERATION;
peer -> packetThrottleDeceleration = ENET_PEER_PACKET_THROTTLE_DECELERATION;
peer -> packetThrottleInterval = ENET_PEER_PACKET_THROTTLE_INTERVAL;
peer -> lastRoundTripTime = ENET_PEER_DEFAULT_ROUND_TRIP_TIME;
peer -> lowestRoundTripTime = ENET_PEER_DEFAULT_ROUND_TRIP_TIME;
peer -> lastRoundTripTimeVariance = 0;
peer -> highestRoundTripTimeVariance = 0;
peer -> roundTripTime = ENET_PEER_DEFAULT_ROUND_TRIP_TIME;
peer -> roundTripTimeVariance = 0;
peer -> mtu = peer -> host -> mtu;
peer -> reliableDataInTransit = 0;
peer -> outgoingReliableSequenceNumber = 0;
peer -> windowSize = ENET_PROTOCOL_MAXIMUM_WINDOW_SIZE;
enet_peer_reset_queues (peer);
}
/** Sends a ping request to a peer.
@param peer destination for the ping request
@remarks ping requests factor into the mean round trip time as designated by the
roundTripTime field in the ENetPeer structure. Enet automatically pings all connected
peers at regular intervals, however, this function may be called to ensure more
frequent ping requests.
*/
void
enet_peer_ping (ENetPeer * peer)
{
ENetProtocol command;
if (peer -> state != ENET_PEER_STATE_CONNECTED)
return;
command.header.command = ENET_PROTOCOL_COMMAND_PING;
command.header.channelID = 0xFF;
command.header.flags = ENET_PROTOCOL_FLAG_ACKNOWLEDGE;
command.header.commandLength = sizeof (ENetProtocolPing);
enet_peer_queue_outgoing_command (peer, & command, NULL, 0, 0);
}
/** Force an immediate disconnection from a peer.
@param peer peer to disconnect
@remarks No ENET_EVENT_DISCONNECT event will be generated. The foreign peer is not
guarenteed to receive the disconnect notification, and is reset immediately upon
return from this function.
*/
void
enet_peer_disconnect_now (ENetPeer * peer)
{
ENetProtocol command;
if (peer -> state != ENET_PEER_STATE_DISCONNECTED)
return;
if (peer -> state != ENET_PEER_STATE_ZOMBIE &&
peer -> state != ENET_PEER_STATE_DISCONNECTING)
{
enet_peer_reset_queues (peer);
command.header.command = ENET_PROTOCOL_COMMAND_DISCONNECT;
command.header.channelID = 0xFF;
command.header.flags = 0;
command.header.commandLength = sizeof (ENetProtocolDisconnect);
enet_peer_queue_outgoing_command (peer, & command, NULL, 0, 0);
enet_host_flush (peer -> host);
}
enet_peer_reset (peer);
}
/** Request a disconnection from a peer.
@param peer peer to request a disconnection
@remarks An ENET_EVENT_DISCONNECT event will be generated by enet_host_service()
once the disconnection is complete.
*/
void
enet_peer_disconnect (ENetPeer * peer)
{
ENetProtocol command;
if (peer -> state == ENET_PEER_STATE_DISCONNECTING ||
peer -> state == ENET_PEER_STATE_DISCONNECTED ||
peer -> state == ENET_PEER_STATE_ZOMBIE)
return;
enet_peer_reset_queues (peer);
command.header.command = ENET_PROTOCOL_COMMAND_DISCONNECT;
command.header.channelID = 0xFF;
command.header.flags = 0;
command.header.commandLength = sizeof (ENetProtocolDisconnect);
if (peer -> state == ENET_PEER_STATE_CONNECTED)
command.header.flags |= ENET_PROTOCOL_FLAG_ACKNOWLEDGE;
enet_peer_queue_outgoing_command (peer, & command, NULL, 0, 0);
if (peer -> state == ENET_PEER_STATE_CONNECTED)
peer -> state = ENET_PEER_STATE_DISCONNECTING;
else
{
enet_host_flush (peer -> host);
enet_peer_reset (peer);
}
}
ENetAcknowledgement *
enet_peer_queue_acknowledgement (ENetPeer * peer, const ENetProtocol * command, enet_uint32 sentTime)
{
ENetAcknowledgement * acknowledgement;
peer -> outgoingDataTotal += sizeof (ENetProtocolAcknowledge);
acknowledgement = (ENetAcknowledgement *) enet_malloc (sizeof (ENetAcknowledgement));
acknowledgement -> sentTime = sentTime;
acknowledgement -> command = * command;
enet_list_insert (enet_list_end (& peer -> acknowledgements), acknowledgement);
return acknowledgement;
}
ENetOutgoingCommand *
enet_peer_queue_outgoing_command (ENetPeer * peer, const ENetProtocol * command, ENetPacket * packet, enet_uint32 offset, enet_uint16 length)
{
ENetChannel * channel = & peer -> channels [command -> header.channelID];
ENetOutgoingCommand * outgoingCommand;
peer -> outgoingDataTotal += command -> header.commandLength + length;
outgoingCommand = (ENetOutgoingCommand *) enet_malloc (sizeof (ENetOutgoingCommand));
if (command -> header.channelID == 0xFF)
{
++ peer -> outgoingReliableSequenceNumber;
outgoingCommand -> reliableSequenceNumber = peer -> outgoingReliableSequenceNumber;
outgoingCommand -> unreliableSequenceNumber = 0;
}
else
if (command -> header.flags & ENET_PROTOCOL_FLAG_ACKNOWLEDGE)
{
++ channel -> outgoingReliableSequenceNumber;
outgoingCommand -> reliableSequenceNumber = channel -> outgoingReliableSequenceNumber;
outgoingCommand -> unreliableSequenceNumber = 0;
}
else
{
++ channel -> outgoingUnreliableSequenceNumber;
outgoingCommand -> reliableSequenceNumber = channel -> outgoingReliableSequenceNumber;
outgoingCommand -> unreliableSequenceNumber = channel -> outgoingUnreliableSequenceNumber;
}
outgoingCommand -> sentTime = 0;
outgoingCommand -> roundTripTimeout = 0;
outgoingCommand -> roundTripTimeoutLimit = 0;
outgoingCommand -> fragmentOffset = offset;
outgoingCommand -> fragmentLength = length;
outgoingCommand -> packet = packet;
outgoingCommand -> command = * command;
outgoingCommand -> command.header.reliableSequenceNumber = ENET_HOST_TO_NET_32 (outgoingCommand -> reliableSequenceNumber);
if (packet != NULL)
++ packet -> referenceCount;
if (command -> header.flags & ENET_PROTOCOL_FLAG_ACKNOWLEDGE)
enet_list_insert (enet_list_end (& peer -> outgoingReliableCommands), outgoingCommand);
else
enet_list_insert (enet_list_end (& peer -> outgoingUnreliableCommands), outgoingCommand);
return outgoingCommand;
}
ENetIncomingCommand *
enet_peer_queue_incoming_command (ENetPeer * peer, const ENetProtocol * command, ENetPacket * packet, enet_uint32 fragmentCount)
{
ENetChannel * channel = & peer -> channels [command -> header.channelID];
enet_uint32 unreliableSequenceNumber = 0;
ENetIncomingCommand * incomingCommand;
ENetListIterator currentCommand;
if (command -> header.command == ENET_PROTOCOL_COMMAND_SEND_UNRELIABLE)
unreliableSequenceNumber = ENET_NET_TO_HOST_32 (command -> sendUnreliable.unreliableSequenceNumber);
if (unreliableSequenceNumber == 0)
{
for (currentCommand = enet_list_previous (enet_list_end (& channel -> incomingReliableCommands));
currentCommand != enet_list_end (& channel -> incomingReliableCommands);
currentCommand = enet_list_previous (currentCommand))
{
incomingCommand = (ENetIncomingCommand *) currentCommand;
if (incomingCommand -> reliableSequenceNumber <= command -> header.reliableSequenceNumber)
{
if (incomingCommand -> reliableSequenceNumber < command -> header.reliableSequenceNumber)
break;
goto freePacket;
}
}
}
else
{
if (command -> header.reliableSequenceNumber < channel -> incomingReliableSequenceNumber)
goto freePacket;
if (unreliableSequenceNumber <= channel -> incomingUnreliableSequenceNumber)
goto freePacket;
for (currentCommand = enet_list_previous (enet_list_end (& channel -> incomingUnreliableCommands));
currentCommand != enet_list_end (& channel -> incomingUnreliableCommands);
currentCommand = enet_list_previous (currentCommand))
{
incomingCommand = (ENetIncomingCommand *) currentCommand;
if (incomingCommand -> unreliableSequenceNumber <= unreliableSequenceNumber)
{
if (incomingCommand -> unreliableSequenceNumber < unreliableSequenceNumber)
break;
goto freePacket;
}
}
}
incomingCommand = (ENetIncomingCommand *) enet_malloc (sizeof (ENetIncomingCommand));
incomingCommand -> reliableSequenceNumber = command -> header.reliableSequenceNumber;
incomingCommand -> unreliableSequenceNumber = unreliableSequenceNumber;
incomingCommand -> command = * command;
incomingCommand -> fragmentCount = fragmentCount;
incomingCommand -> fragmentsRemaining = fragmentCount;
incomingCommand -> packet = packet;
if (fragmentCount > 0)
incomingCommand -> fragments = (enet_uint32 *) enet_calloc ((fragmentCount + 31) / 32, sizeof (enet_uint32));
else
incomingCommand -> fragments = NULL;
if (packet != NULL)
++ packet -> referenceCount;
enet_list_insert (enet_list_next (currentCommand), incomingCommand);
return incomingCommand;
freePacket:
if (packet != NULL)
{
if (packet -> referenceCount == 0)
enet_packet_destroy (packet);
}
return NULL;
}
/** @} */