/** 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;
if (peerCount > ENET_PROTOCOL_MAXIMUM_PEER_ID)
return NULL;
host -> peers = (ENetPeer *) enet_malloc (peerCount * sizeof (ENetPeer));
memset (host -> peers, 0, 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;
}
/** 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.
@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 ||
channelID >= peer -> channelCount)
return -1;
fragmentLength = peer -> mtu - sizeof (ENetProtocolHeader) - sizeof (ENetProtocolSendFragment);
if (packet -> dataLength > fragmentLength)
{
enet_uint16 startSequenceNumber = ENET_HOST_TO_NET_16 (channel -> outgoingReliableSequenceNumber + 1);
enet_uint32 fragmentCount = ENET_HOST_TO_NET_32 ((packet -> dataLength + fragmentLength - 1) / fragmentLength),
fragmentNumber,
fragmentOffset;
ENetList fragments;
ENetOutgoingCommand * fragment;
enet_list_clear (& fragments);
for (fragmentNumber = 0,
fragmentOffset = 0;
fragmentOffset < packet -> dataLength;
++ fragmentNumber,
fragmentOffset += fragmentLength)
{
if (packet -> dataLength - fragmentOffset < fragmentLength)
fragmentLength = packet -> dataLength - fragmentOffset;
fragment = (ENetOutgoingCommand *) enet_malloc (sizeof (ENetOutgoingCommand));
if (fragment == NULL)
{
while (! enet_list_empty (& fragments))
{
fragment = (ENetOutgoingCommand *) enet_list_remove (enet_list_begin (& fragments));
enet_free (fragment);
}
return -1;
}
fragment -> fragmentOffset = fragmentOffset;
fragment -> fragmentLength = fragmentLength;
fragment -> packet = packet;
fragment -> command.header.command = ENET_PROTOCOL_COMMAND_SEND_FRAGMENT | ENET_PROTOCOL_COMMAND_FLAG_ACKNOWLEDGE;
fragment -> command.header.channelID = channelID;
fragment -> command.sendFragment.startSequenceNumber = startSequenceNumber;
fragment -> command.sendFragment.dataLength = ENET_HOST_TO_NET_16 (fragmentLength);
fragment -> command.sendFragment.fragmentCount = fragmentCount;
fragment -> command.sendFragment.fragmentNumber = ENET_HOST_TO_NET_32 (fragmentNumber);
fragment -> command.sendFragment.totalLength = ENET_HOST_TO_NET_32 (packet -> dataLength);
fragment -> command.sendFragment.fragmentOffset = ENET_NET_TO_HOST_32 (fragmentOffset);
enet_list_insert (enet_list_end (& fragments), fragment);
}
packet -> referenceCount += fragmentNumber;
while (! enet_list_empty (& fragments))
{
fragment = (ENetOutgoingCommand *) enet_list_remove (enet_list_begin (& fragments));
enet_peer_setup_outgoing_command (peer, fragment);
}
return 0;
}
command.header.channelID = channelID;
if (packet -> flags & ENET_PACKET_FLAG_RELIABLE)
{
command.header.command = ENET_PROTOCOL_COMMAND_SEND_RELIABLE | ENET_PROTOCOL_COMMAND_FLAG_ACKNOWLEDGE;
command.sendReliable.dataLength = ENET_HOST_TO_NET_16 (packet -> dataLength);
}
else
if (packet -> flags & ENET_PACKET_FLAG_UNSEQUENCED)
{
command.header.command = ENET_PROTOCOL_COMMAND_SEND_UNSEQUENCED | ENET_PROTOCOL_COMMAND_FLAG_UNSEQUENCED;
command.sendUnsequenced.unsequencedGroup = ENET_HOST_TO_NET_16 (peer -> outgoingUnsequencedGroup + 1);
command.sendUnsequenced.dataLength = ENET_HOST_TO_NET_16 (packet -> dataLength);
}
else
if (channel -> outgoingUnreliableSequenceNumber >= 0xFFFF)
{
command.header.command = ENET_PROTOCOL_COMMAND_SEND_RELIABLE | ENET_PROTOCOL_COMMAND_FLAG_ACKNOWLEDGE;
command.sendReliable.dataLength = ENET_HOST_TO_NET_16 (packet -> dataLength);
}
else
{
command.header.command = ENET_PROTOCOL_COMMAND_SEND_UNRELIABLE;
command.sendUnreliable.unreliableSequenceNumber = ENET_HOST_TO_NET_16 (channel -> outgoingUnreliableSequenceNumber + 1);
command.sendUnreliable.dataLength = ENET_HOST_TO_NET_16 (packet -> dataLength);
}
if (enet_peer_queue_outgoing_command (peer, & command, packet, 0, packet -> dataLength) == NULL)
return -1;
return 0;
}
static ENetPeer *
enet_protocol_handle_connect (ENetHost * host, const ENetProtocolHeader * header, const ENetProtocol * command)
{
enet_uint16 mtu;
enet_uint32 windowSize;
ENetChannel * channel;
size_t channelCount;
ENetPeer * currentPeer;
ENetProtocol verifyCommand;
if (command -> header.commandLength < sizeof (ENetProtocolConnect))
return NULL;
channelCount = ENET_NET_TO_HOST_32 (command -> connect.channelCount);
if (channelCount < ENET_PROTOCOL_MINIMUM_CHANNEL_COUNT ||
channelCount > ENET_PROTOCOL_MAXIMUM_CHANNEL_COUNT)
return NULL;
for (currentPeer = host -> peers;
currentPeer < & host -> peers [host -> peerCount];
++ currentPeer)
{
if (currentPeer -> state != ENET_PEER_STATE_DISCONNECTED &&
currentPeer -> address.host == host -> receivedAddress.host &&
currentPeer -> address.port == host -> receivedAddress.port &&
currentPeer -> challenge == header -> challenge)
return NULL;
}
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_ACKNOWLEDGING_CONNECT;
currentPeer -> challenge = header -> challenge;
currentPeer -> address = host -> receivedAddress;
currentPeer -> outgoingPeerID = ENET_NET_TO_HOST_16 (command -> connect.outgoingPeerID);
currentPeer -> incomingBandwidth = ENET_NET_TO_HOST_32 (command -> connect.incomingBandwidth);
currentPeer -> outgoingBandwidth = ENET_NET_TO_HOST_32 (command -> connect.outgoingBandwidth);
currentPeer -> packetThrottleInterval = ENET_NET_TO_HOST_32 (command -> connect.packetThrottleInterval);
currentPeer -> packetThrottleAcceleration = ENET_NET_TO_HOST_32 (command -> connect.packetThrottleAcceleration);
currentPeer -> packetThrottleDeceleration = ENET_NET_TO_HOST_32 (command -> connect.packetThrottleDeceleration);
currentPeer -> channels = (ENetChannel *) enet_malloc (channelCount * sizeof (ENetChannel));
currentPeer -> channelCount = channelCount;
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);
}
mtu = ENET_NET_TO_HOST_16 (command -> connect.mtu);
if (mtu < ENET_PROTOCOL_MINIMUM_MTU)
mtu = ENET_PROTOCOL_MINIMUM_MTU;
else
if (mtu > ENET_PROTOCOL_MAXIMUM_MTU)
mtu = ENET_PROTOCOL_MAXIMUM_MTU;
currentPeer -> mtu = mtu;
if (host -> outgoingBandwidth == 0 &&
currentPeer -> incomingBandwidth == 0)
currentPeer -> windowSize = ENET_PROTOCOL_MAXIMUM_WINDOW_SIZE;
else
currentPeer -> windowSize = (ENET_MIN (host -> outgoingBandwidth, currentPeer -> incomingBandwidth) /
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;
if (host -> incomingBandwidth == 0)
windowSize = ENET_PROTOCOL_MAXIMUM_WINDOW_SIZE;
else
windowSize = (host -> incomingBandwidth / ENET_PEER_WINDOW_SIZE_SCALE) *
ENET_PROTOCOL_MINIMUM_WINDOW_SIZE;
if (windowSize > ENET_NET_TO_HOST_32 (command -> connect.windowSize))
windowSize = ENET_NET_TO_HOST_32 (command -> connect.windowSize);
if (windowSize < ENET_PROTOCOL_MINIMUM_WINDOW_SIZE)
windowSize = ENET_PROTOCOL_MINIMUM_WINDOW_SIZE;
else
if (windowSize > ENET_PROTOCOL_MAXIMUM_WINDOW_SIZE)
windowSize = ENET_PROTOCOL_MAXIMUM_WINDOW_SIZE;
verifyCommand.header.command = ENET_PROTOCOL_COMMAND_VERIFY_CONNECT;
verifyCommand.header.channelID = 0xFF;
verifyCommand.header.flags = ENET_PROTOCOL_FLAG_ACKNOWLEDGE;
verifyCommand.header.commandLength = sizeof (ENetProtocolVerifyConnect);
verifyCommand.verifyConnect.outgoingPeerID = ENET_HOST_TO_NET_16 (currentPeer -> incomingPeerID);
verifyCommand.verifyConnect.mtu = ENET_HOST_TO_NET_16 (currentPeer -> mtu);
verifyCommand.verifyConnect.windowSize = ENET_HOST_TO_NET_32 (windowSize);
verifyCommand.verifyConnect.channelCount = ENET_HOST_TO_NET_32 (channelCount);
verifyCommand.verifyConnect.incomingBandwidth = ENET_HOST_TO_NET_32 (host -> incomingBandwidth);
verifyCommand.verifyConnect.outgoingBandwidth = ENET_HOST_TO_NET_32 (host -> outgoingBandwidth);
verifyCommand.verifyConnect.packetThrottleInterval = ENET_HOST_TO_NET_32 (currentPeer -> packetThrottleInterval);
verifyCommand.verifyConnect.packetThrottleAcceleration = ENET_HOST_TO_NET_32 (currentPeer -> packetThrottleAcceleration);
verifyCommand.verifyConnect.packetThrottleDeceleration = ENET_HOST_TO_NET_32 (currentPeer -> packetThrottleDeceleration);
enet_peer_queue_outgoing_command (currentPeer, & verifyCommand, NULL, 0, 0);
return currentPeer;
}
