ref: 935b2d59612ac7945a17b8025848fe1e3c94fc1f
dir: /Engine/src/enet/host.c/
/**
@file host.c
@brief ENet host management functions
*/
#define ENET_BUILDING_LIB 1
#include "memory.h"
#include "enet.h"
/** @defgroup host ENet host functions
@{
*/
/** Creates a host for communicating to peers.
@param address the address at which other peers may connect to this host. If NULL, then no peers may connect to the host.
@param peerCount the maximum number of peers that should be allocated for the host.
@param incomingBandwidth downstream bandwidth of the host in bytes/second; if 0, ENet will assume unlimited bandwidth.
@param outgoingBandwidth upstream bandwidth of the host in bytes/second; if 0, ENet will assume unlimited bandwidth.
@returns the host on success and NULL on failure
@remarks ENet will strategically drop packets on specific sides of a connection between hosts
to ensure the host's bandwidth is not overwhelmed. The bandwidth parameters also determine
the window size of a connection which limits the amount of reliable packets that may be in transit
at any given time.
*/
ENetHost *
enet_host_create (const ENetAddress * address, size_t peerCount, enet_uint32 incomingBandwidth, enet_uint32 outgoingBandwidth)
{
ENetHost * host = (ENetHost *) enet_malloc (sizeof (ENetHost));
ENetPeer * currentPeer;
host -> peers = (ENetPeer *) enet_calloc (peerCount, sizeof (ENetPeer));
host -> socket = enet_socket_create (ENET_SOCKET_TYPE_DATAGRAM, address);
if (host -> socket == ENET_SOCKET_NULL)
{
enet_free (host -> peers);
enet_free (host);
return NULL;
}
if (address != NULL)
host -> address = * address;
host -> incomingBandwidth = incomingBandwidth;
host -> outgoingBandwidth = outgoingBandwidth;
host -> bandwidthThrottleEpoch = 0;
host -> recalculateBandwidthLimits = 0;
host -> mtu = ENET_HOST_DEFAULT_MTU;
host -> peerCount = peerCount;
host -> lastServicedPeer = host -> peers;
host -> commandCount = 0;
host -> bufferCount = 0;
host -> receivedAddress.host = ENET_HOST_ANY;
host -> receivedAddress.port = 0;
host -> receivedDataLength = 0;
for (currentPeer = host -> peers;
currentPeer < & host -> peers [host -> peerCount];
++ currentPeer)
{
currentPeer -> host = host;
currentPeer -> incomingPeerID = currentPeer - host -> peers;
currentPeer -> data = NULL;
enet_list_clear (& currentPeer -> acknowledgements);
enet_list_clear (& currentPeer -> sentReliableCommands);
enet_list_clear (& currentPeer -> sentUnreliableCommands);
enet_list_clear (& currentPeer -> outgoingReliableCommands);
enet_list_clear (& currentPeer -> outgoingUnreliableCommands);
enet_peer_reset (currentPeer);
}
return host;
}
/** Destroys the host and all resources associated with it.
@param host pointer to the host to destroy
*/
void
enet_host_destroy (ENetHost * host)
{
ENetPeer * currentPeer;
enet_socket_destroy (host -> socket);
for (currentPeer = host -> peers;
currentPeer < & host -> peers [host -> peerCount];
++ currentPeer)
{
enet_peer_reset (currentPeer);
}
enet_free (host -> peers);
enet_free (host);
}
/** Initiates a connection to a foreign host.
@param host host seeking the connection
@param address destination for the connection
@param channelCount number of channels to allocate
@returns a peer representing the foreign host on success, NULL on failure
@remarks The peer returned will have not completed the connection until enet_host_service()
notifies of an ENET_EVENT_TYPE_CONNECT event for the peer.
*/
ENetPeer *
enet_host_connect (ENetHost * host, const ENetAddress * address, size_t channelCount)
{
ENetPeer * currentPeer;
ENetChannel * channel;
ENetProtocol command;
if (channelCount < ENET_PROTOCOL_MINIMUM_CHANNEL_COUNT)
channelCount = ENET_PROTOCOL_MINIMUM_CHANNEL_COUNT;
else
if (channelCount > ENET_PROTOCOL_MAXIMUM_CHANNEL_COUNT)
channelCount = ENET_PROTOCOL_MAXIMUM_CHANNEL_COUNT;
for (currentPeer = host -> peers;
currentPeer < & host -> peers [host -> peerCount];
++ currentPeer)
{
if (currentPeer -> state == ENET_PEER_STATE_DISCONNECTED)
break;
}
if (currentPeer >= & host -> peers [host -> peerCount])
return NULL;
currentPeer -> state = ENET_PEER_STATE_CONNECTING;
currentPeer -> address = * address;
currentPeer -> channels = (ENetChannel *) enet_malloc (channelCount * sizeof (ENetChannel));
currentPeer -> channelCount = channelCount;
currentPeer -> challenge = (enet_uint32) rand ();
if (host -> outgoingBandwidth == 0)
currentPeer -> windowSize = ENET_PROTOCOL_MAXIMUM_WINDOW_SIZE;
else
currentPeer -> windowSize = (host -> outgoingBandwidth /
ENET_PEER_WINDOW_SIZE_SCALE) *
ENET_PROTOCOL_MINIMUM_WINDOW_SIZE;
if (currentPeer -> windowSize < ENET_PROTOCOL_MINIMUM_WINDOW_SIZE)
currentPeer -> windowSize = ENET_PROTOCOL_MINIMUM_WINDOW_SIZE;
else
if (currentPeer -> windowSize > ENET_PROTOCOL_MAXIMUM_WINDOW_SIZE)
currentPeer -> windowSize = ENET_PROTOCOL_MAXIMUM_WINDOW_SIZE;
for (channel = currentPeer -> channels;
channel < & currentPeer -> channels [channelCount];
++ channel)
{
channel -> outgoingReliableSequenceNumber = 0;
channel -> outgoingUnreliableSequenceNumber = 0;
channel -> incomingReliableSequenceNumber = 0;
channel -> incomingUnreliableSequenceNumber = 0;
enet_list_clear (& channel -> incomingReliableCommands);
enet_list_clear (& channel -> incomingUnreliableCommands);
}
command.header.command = ENET_PROTOCOL_COMMAND_CONNECT;
command.header.channelID = 0xFF;
command.header.flags = ENET_PROTOCOL_FLAG_ACKNOWLEDGE;
command.header.commandLength = sizeof (ENetProtocolConnect);
command.connect.outgoingPeerID = ENET_HOST_TO_NET_16 (currentPeer -> incomingPeerID);
command.connect.mtu = ENET_HOST_TO_NET_16 (currentPeer -> mtu);
command.connect.windowSize = ENET_HOST_TO_NET_32 (currentPeer -> windowSize);
command.connect.channelCount = ENET_HOST_TO_NET_32 (channelCount);
command.connect.incomingBandwidth = ENET_HOST_TO_NET_32 (host -> incomingBandwidth);
command.connect.outgoingBandwidth = ENET_HOST_TO_NET_32 (host -> outgoingBandwidth);
command.connect.packetThrottleInterval = ENET_HOST_TO_NET_32 (currentPeer -> packetThrottleInterval);
command.connect.packetThrottleAcceleration = ENET_HOST_TO_NET_32 (currentPeer -> packetThrottleAcceleration);
command.connect.packetThrottleDeceleration = ENET_HOST_TO_NET_32 (currentPeer -> packetThrottleDeceleration);
enet_peer_queue_outgoing_command (currentPeer, & command, NULL, 0, 0);
return currentPeer;
}
/** Queues a packet to be sent to all peers associated with the host.
@param host host on which to broadcast the packet
@param channelID channel on which to broadcast
@param packet packet to broadcast
*/
void
enet_host_broadcast (ENetHost * host, enet_uint8 channelID, ENetPacket * packet)
{
ENetPeer * currentPeer;
for (currentPeer = host -> peers;
currentPeer < & host -> peers [host -> peerCount];
++ currentPeer)
{
if (currentPeer -> state != ENET_PEER_STATE_CONNECTED)
continue;
enet_peer_send (currentPeer, channelID, packet);
}
if (packet -> referenceCount == 0)
enet_packet_destroy (packet);
}
/** Adjusts the bandwidth limits of a host.
@param host host to adjust
@param incomingBandwidth new incoming bandwidth
@param outgoingBandwidth new outgoing bandwidth
@remarks the incoming and outgoing bandwidth parameters are identical in function to those
specified in enet_host_create().
*/
void
enet_host_bandwidth_limit (ENetHost * host, enet_uint32 incomingBandwidth, enet_uint32 outgoingBandwidth)
{
host -> incomingBandwidth = incomingBandwidth;
host -> outgoingBandwidth = outgoingBandwidth;
host -> recalculateBandwidthLimits = 1;
}
void
enet_host_bandwidth_throttle (ENetHost * host)
{
enet_uint32 timeCurrent = enet_time_get (),
elapsedTime = timeCurrent - host -> bandwidthThrottleEpoch,
peersTotal = 0,
dataTotal = 0,
peersRemaining,
bandwidth,
throttle = 0,
bandwidthLimit = 0;
int needsAdjustment;
ENetPeer * peer;
ENetProtocol command;
if (elapsedTime < ENET_HOST_BANDWIDTH_THROTTLE_INTERVAL)
return;
for (peer = host -> peers;
peer < & host -> peers [host -> peerCount];
++ peer)
{
if (peer -> state != ENET_PEER_STATE_CONNECTED)
continue;
++ peersTotal;
dataTotal += peer -> outgoingDataTotal;
}
if (peersTotal == 0)
return;
peersRemaining = peersTotal;
needsAdjustment = 1;
if (host -> outgoingBandwidth == 0)
bandwidth = ~0;
else
bandwidth = (host -> outgoingBandwidth * elapsedTime) / 1000;
while (peersRemaining > 0 && needsAdjustment != 0)
{
needsAdjustment = 0;
if (dataTotal < bandwidth)
throttle = ENET_PEER_PACKET_THROTTLE_SCALE;
else
throttle = (bandwidth * ENET_PEER_PACKET_THROTTLE_SCALE) / dataTotal;
for (peer = host -> peers;
peer < & host -> peers [host -> peerCount];
++ peer)
{
enet_uint32 peerBandwidth;
if (peer -> state != ENET_PEER_STATE_CONNECTED ||
peer -> incomingBandwidth == 0 ||
peer -> outgoingBandwidthThrottleEpoch == timeCurrent)
continue;
peerBandwidth = (peer -> incomingBandwidth * elapsedTime) / 1000;
if ((throttle * peer -> outgoingDataTotal) / ENET_PEER_PACKET_THROTTLE_SCALE <= peerBandwidth)
continue;
peer -> packetThrottleLimit = (peerBandwidth *
ENET_PEER_PACKET_THROTTLE_SCALE) / peer -> outgoingDataTotal;
if (peer -> packetThrottleLimit == 0)
peer -> packetThrottleLimit = 1;
if (peer -> packetThrottle > peer -> packetThrottleLimit)
peer -> packetThrottle = peer -> packetThrottleLimit;
peer -> outgoingBandwidthThrottleEpoch = timeCurrent;
needsAdjustment = 1;
-- peersRemaining;
bandwidth -= peerBandwidth;
dataTotal -= peerBandwidth;
}
}
if (peersRemaining > 0)
for (peer = host -> peers;
peer < & host -> peers [host -> peerCount];
++ peer)
{
if (peer -> state != ENET_PEER_STATE_CONNECTED ||
peer -> outgoingBandwidthThrottleEpoch == timeCurrent)
continue;
peer -> packetThrottleLimit = throttle;
if (peer -> packetThrottle > peer -> packetThrottleLimit)
peer -> packetThrottle = peer -> packetThrottleLimit;
}
if (host -> recalculateBandwidthLimits)
{
host -> recalculateBandwidthLimits = 0;
peersRemaining = peersTotal;
bandwidth = host -> incomingBandwidth;
needsAdjustment = 1;
if (bandwidth == 0)
bandwidthLimit = 0;
else
while (peersRemaining > 0 && needsAdjustment != 0)
{
needsAdjustment = 0;
bandwidthLimit = bandwidth / peersRemaining;
for (peer = host -> peers;
peer < & host -> peers [host -> peerCount];
++ peer)
{
if (peer -> state != ENET_PEER_STATE_CONNECTED ||
peer -> incomingBandwidthThrottleEpoch == timeCurrent)
continue;
if (peer -> outgoingBandwidth > 0 &&
bandwidthLimit > peer -> outgoingBandwidth)
continue;
peer -> incomingBandwidthThrottleEpoch = timeCurrent;
needsAdjustment = 1;
-- peersRemaining;
bandwidth -= peer -> outgoingBandwidth;
}
}
for (peer = host -> peers;
peer < & host -> peers [host -> peerCount];
++ peer)
{
if (peer -> state != ENET_PEER_STATE_CONNECTED)
continue;
command.header.command = ENET_PROTOCOL_COMMAND_BANDWIDTH_LIMIT;
command.header.channelID = 0xFF;
command.header.flags = 0;
command.header.commandLength = sizeof (ENetProtocolBandwidthLimit);
command.bandwidthLimit.outgoingBandwidth = ENET_HOST_TO_NET_32 (host -> outgoingBandwidth);
if (peer -> incomingBandwidthThrottleEpoch == timeCurrent)
command.bandwidthLimit.incomingBandwidth = ENET_HOST_TO_NET_32 (peer -> outgoingBandwidth);
else
command.bandwidthLimit.incomingBandwidth = ENET_HOST_TO_NET_32 (bandwidthLimit);
enet_peer_queue_outgoing_command (peer, & command, NULL, 0, 0);
}
}
host -> bandwidthThrottleEpoch = timeCurrent;
for (peer = host -> peers;
peer < & host -> peers [host -> peerCount];
++ peer)
{
peer -> incomingDataTotal = 0;
peer -> outgoingDataTotal = 0;
}
}
/** @} */