diff options
Diffstat (limited to 'peer.c')
| -rw-r--r-- | peer.c | 644 |
1 files changed, 644 insertions, 0 deletions
@@ -0,0 +1,644 @@ +/** + @file peer.c + @brief ENet peer management functions +*/ +#define ENET_BUILDING_LIB 1 +#include "enet/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 = ENET_PROTOCOL_FLAG_ACKNOWLEDGE; + 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 || + channelID >= peer -> channelCount) + 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 + if (packet -> flags & ENET_PACKET_FLAG_UNSEQUENCED) + { + command.header.command = ENET_PROTOCOL_COMMAND_SEND_UNSEQUENCED; + command.header.flags = ENET_PROTOCOL_FLAG_UNSEQUENCED; + command.header.commandLength = sizeof (ENetProtocolSendUnsequenced); + command.sendUnsequenced.unsequencedGroup = ENET_HOST_TO_NET_32 (peer -> outgoingUnsequencedGroup + 1); + } + 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 -> unreliableSequenceNumber > 0) + { + 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; + peer -> incomingUnsequencedGroup = 0; + peer -> outgoingUnsequencedGroup = 0; + + memset (peer -> unsequencedWindow, 0, sizeof (peer -> unsequencedWindow)); + + 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 = ENET_PROTOCOL_FLAG_UNSEQUENCED; + 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 = ENET_PROTOCOL_FLAG_UNSEQUENCED; + 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 + if (command -> header.flags & ENET_PROTOCOL_FLAG_UNSEQUENCED) + { + 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; + + switch (command -> header.command) + { + case ENET_PROTOCOL_COMMAND_SEND_RELIABLE: + 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; + } + } + break; + + case ENET_PROTOCOL_COMMAND_SEND_UNRELIABLE: + unreliableSequenceNumber = ENET_NET_TO_HOST_32 (command -> sendUnreliable.unreliableSequenceNumber); + + 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; + } + } + break; + + case ENET_PROTOCOL_COMMAND_SEND_UNSEQUENCED: + currentCommand = enet_list_end (& channel -> incomingUnreliableCommands); + break; + + default: + 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; + incomingCommand -> fragments = NULL; + + if (fragmentCount > 0) + { + incomingCommand -> fragments = (enet_uint32 *) enet_malloc ((fragmentCount + 31) / 32 * sizeof (enet_uint32)); + memset (incomingCommand -> fragments, 0, (fragmentCount + 31) / 32 * sizeof (enet_uint32)); + } + + 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; +} + +/** @} */ |