Files
UnrealEngine/Engine/Source/Runtime/Networking/Public/Common/UdpSocketBuilder.h
2025-05-18 13:04:45 +08:00

449 lines
12 KiB
C++

// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
#include "CoreMinimal.h"
#include "Misc/OutputDeviceRedirector.h"
#include "Sockets.h"
#include "SocketSubsystem.h"
#include "Interfaces/IPv4/IPv4Address.h"
#include "Interfaces/IPv4/IPv4Endpoint.h"
class Error;
/**
* Implements a fluent builder for UDP sockets.
*/
class FUdpSocketBuilder
{
public:
/**
* Creates and initializes a new instance.
*
* @param InDescription Debug description for the socket.
*/
FUdpSocketBuilder(const FString& InDescription)
: AllowBroadcast(false)
, Blocking(false)
, Bound(false)
, BoundEndpoint(FIPv4Address::Any, 0)
, Description(InDescription)
, MulticastInterface(FIPv4Address::Any)
, MulticastLoopback(false)
, MulticastTtl(1)
, ReceiveBufferSize(0)
, Reusable(false)
, SendBufferSize(0)
{ }
public:
/**
* Sets socket operations to be blocking.
*
* @return This instance (for method chaining).
* @see AsNonBlocking, AsReusable
*/
FUdpSocketBuilder& AsBlocking()
{
Blocking = true;
return *this;
}
/**
* Sets socket operations to be non-blocking.
*
* @return This instance (for method chaining).
* @see AsBlocking, AsReusable
*/
FUdpSocketBuilder& AsNonBlocking()
{
Blocking = false;
return *this;
}
/**
* Makes the bound address reusable by other sockets.
*
* @return This instance (for method chaining).
* @see AsBlocking, AsNonBlocking
*/
FUdpSocketBuilder& AsReusable()
{
Reusable = true;
return *this;
}
/**
* Sets the local address to bind the socket to.
*
* Unless specified in a subsequent call to BoundToPort(), a random
* port number will be assigned by the underlying provider.
*
* @param Address The IP address to bind the socket to.
* @return This instance (for method chaining).
* @see BoundToEndpoint, BoundToPort
*/
FUdpSocketBuilder& BoundToAddress(const FIPv4Address& Address)
{
BoundEndpoint = FIPv4Endpoint(Address, BoundEndpoint.Port);
Bound = true;
return *this;
}
/**
* Sets the local endpoint to bind the socket to.
*
* @param Endpoint The IP endpoint to bind the socket to.
* @return This instance (for method chaining).
* @see BoundToAddress, BoundToPort
*/
FUdpSocketBuilder& BoundToEndpoint(const FIPv4Endpoint& Endpoint)
{
BoundEndpoint = Endpoint;
Bound = true;
return *this;
}
/**
* Sets the local port to bind the socket to.
*
* Unless specified in a subsequent call to BoundToAddress(), the local
* address will be determined automatically by the underlying provider.
*
* @param Port The local port number to bind the socket to.
* @return This instance (for method chaining).
* @see BoundToAddress
*/
FUdpSocketBuilder& BoundToPort(uint16 Port)
{
BoundEndpoint = FIPv4Endpoint(BoundEndpoint.Address, Port);
Bound = true;
return *this;
}
/**
* Joins the socket to the specified multicast group.
*
* @param GroupAddress The IP address of the multicast group to join.
* @return This instance (for method chaining).
* @see WithMulticastLoopback, WithMulticastTtl
*/
FUdpSocketBuilder& JoinedToGroup(const FIPv4Address& GroupAddress)
{
return JoinedToGroup(GroupAddress, FIPv4Address::Any);
}
/**
* Joins the socket to the specified multicast group.
*
* @param GroupAddress The IP address of the multicast group to join.
* @param InterfaceAddress The IP address of the interface to join the multicast group on.
* @return This instance (for method chaining).
* @see WithMulticastLoopback, WithMulticastTtl
*/
FUdpSocketBuilder& JoinedToGroup(const FIPv4Address& GroupAddress, const FIPv4Address& InterfaceAddress)
{
JoinedGroups.Add({ GroupAddress, InterfaceAddress });
return *this;
}
/**
* Enables broadcasting.
*
* @return This instance (for method chaining).
*/
FUdpSocketBuilder& WithBroadcast()
{
AllowBroadcast = true;
return *this;
}
/**
* Enables multicast loopback.
*
* @param AllowLoopback Whether to allow multicast loopback.
* @param TimeToLive The time to live.
* @return This instance (for method chaining).
* @see JoinedToGroup, WithMulticastTtl
*/
FUdpSocketBuilder& WithMulticastLoopback()
{
MulticastLoopback = true;
return *this;
}
/**
* Sets the multicast time-to-live.
*
* @param TimeToLive The time to live.
* @return This instance (for method chaining).
* @see JoinedToGroup, WithMulticastLoopback
*/
FUdpSocketBuilder& WithMulticastTtl(uint8 TimeToLive)
{
MulticastTtl = TimeToLive;
return *this;
}
/**
* Sets the multicast outgoing interface.
*
* @param InterfaceAddress The interface to use to send multicast datagrams.
* @return This instance (for method chaining).
* @see JoinedToGroup, WithMulticastLoopback
*/
FUdpSocketBuilder& WithMulticastInterface(const FIPv4Address& InterfaceAddress)
{
MulticastInterface = InterfaceAddress;
return *this;
}
/**
* Specifies the desired size of the receive buffer in bytes (0 = default).
*
* The socket creation will not fail if the desired size cannot be set or
* if the actual size is less than the desired size.
*
* @param SizeInBytes The size of the buffer.
* @return This instance (for method chaining).
* @see WithSendBufferSize
*/
FUdpSocketBuilder& WithReceiveBufferSize(int32 SizeInBytes)
{
ReceiveBufferSize = SizeInBytes;
return *this;
}
/**
* Specifies the desired size of the send buffer in bytes (0 = default).
*
* The socket creation will not fail if the desired size cannot be set or
* if the actual size is less than the desired size.
*
* @param SizeInBytes The size of the buffer.
* @return This instance (for method chaining).
* @see WithReceiveBufferSize
*/
FUdpSocketBuilder& WithSendBufferSize(int32 SizeInBytes)
{
SendBufferSize = SizeInBytes;
return *this;
}
public:
/**
* Implicit conversion operator that builds the socket as configured.
*
* @return The built socket.
*/
operator FSocket*() const
{
return Build();
}
/**
* Builds the socket as configured.
*
* @return The built socket.
*/
FSocket* Build() const
{
// load socket subsystem
ISocketSubsystem* SocketSubsystem = ISocketSubsystem::Get(PLATFORM_SOCKETSUBSYSTEM);
if (SocketSubsystem == nullptr)
{
GLog->Log(TEXT("FUdpSocketBuilder: Failed to load socket subsystem"));
return nullptr;
}
// create socket
TSharedRef<FInternetAddr> RemoteAddr = BoundEndpoint.ToInternetAddr();
FSocket* Socket = SocketSubsystem->CreateSocket(NAME_DGram, *Description, RemoteAddr->GetProtocolType());
if (Socket == nullptr)
{
GLog->Logf(TEXT("FUdpSocketBuilder: Failed to create socket %s"), *Description);
return nullptr;
}
// configure socket
if (!Socket->SetNonBlocking(!Blocking) ||
!Socket->SetReuseAddr(Reusable) ||
!Socket->SetBroadcast(AllowBroadcast) ||
!Socket->SetRecvErr())
{
const ESocketErrors SocketError = SocketSubsystem->GetLastErrorCode();
GLog->Logf(TEXT("FUdpSocketBuilder: Failed to configure %s (blocking: %i, reusable: %i, broadcast: %i). Error code %d."),
*Description, Blocking, Reusable, AllowBroadcast, int32(SocketError));
SocketSubsystem->DestroySocket(Socket);
return nullptr;
}
// bind socket
if (Bound && !Socket->Bind(*RemoteAddr))
{
const ESocketErrors SocketError = SocketSubsystem->GetLastErrorCode();
GLog->Logf(TEXT("FUdpSocketBuilder: Failed to bind %s to %s. Error code %d."),
*Description, *BoundEndpoint.ToString(), int32(SocketError));
SocketSubsystem->DestroySocket(Socket);
return nullptr;
}
// configure multicast
if (!Socket->SetMulticastLoopback(MulticastLoopback) || !Socket->SetMulticastTtl(MulticastTtl))
{
const ESocketErrors SocketError = SocketSubsystem->GetLastErrorCode();
GLog->Logf(TEXT("FUdpSocketBuilder: Failed to configure multicast for %s (loopback: %i, ttl: %i). Error code %d."),
*Description, MulticastLoopback, MulticastTtl, int32(SocketError));
SocketSubsystem->DestroySocket(Socket);
return nullptr;
}
// join multicast groups
TSharedRef<FInternetAddr> MulticastAddress = SocketSubsystem->CreateInternetAddr(RemoteAddr->GetProtocolType());
MulticastAddress->SetBroadcastAddress();
TSharedPtr<FInternetAddr> AddressToUse = nullptr;
for (const auto& Group : JoinedGroups)
{
// The Socket code no longer has the multicast address hack handled anymore, as such, we need to properly determine the address ourselves.
if (Group.GroupAddress.IsSessionFrontendMulticast() && MulticastAddress->GetProtocolType() != FNetworkProtocolTypes::IPv4)
{
// This will use the address protocol that we figured out earlier.
AddressToUse = MulticastAddress;
}
else
{
// Otherwise, we'll use the address we use all the time.
AddressToUse = FIPv4Endpoint(Group.GroupAddress, 0).ToInternetAddr();
}
if (!Socket->JoinMulticastGroup(*AddressToUse, *FIPv4Endpoint(Group.InterfaceAddress, 0).ToInternetAddr()))
{
const ESocketErrors SocketError = SocketSubsystem->GetLastErrorCode();
GLog->Logf(TEXT("FUdpSocketBuilder: Failed to subscribe %s to multicast group %s on interface %s. Error code %d."),
*Description, *Group.GroupAddress.ToString(), *Group.InterfaceAddress.ToString(), int32(SocketError));
SocketSubsystem->DestroySocket(Socket);
return nullptr;
}
}
// set multicast outgoing interface
if (MulticastInterface != FIPv4Address::Any)
{
if (!Socket->SetMulticastInterface(*FIPv4Endpoint(MulticastInterface, 0).ToInternetAddr()))
{
const ESocketErrors SocketError = SocketSubsystem->GetLastErrorCode();
GLog->Logf(TEXT("FUdpSocketBuilder: Failed to set multicast outgoing interface for %s to %s. Error code %d."),
*Description, *MulticastInterface.ToString(), int32(SocketError));
SocketSubsystem->DestroySocket(Socket);
return nullptr;
}
}
// set buffer sizes
{
int32 OutNewSize;
if (ReceiveBufferSize > 0)
{
if (!Socket->SetReceiveBufferSize(ReceiveBufferSize, OutNewSize))
{
const ESocketErrors SocketError = SocketSubsystem->GetLastErrorCode();
GLog->Logf(TEXT("FUdpSocketBuilder: Warning - could not set receive buffer size to %d for %s. Error code %d."),
ReceiveBufferSize, *Description, int32(SocketError));
}
}
if (SendBufferSize > 0)
{
if (!Socket->SetSendBufferSize(SendBufferSize, OutNewSize))
{
const ESocketErrors SocketError = SocketSubsystem->GetLastErrorCode();
GLog->Logf(TEXT("FUdpSocketBuilder: Warning - could not set send buffer size to %d for %s. Error code %d."),
SendBufferSize, *Description, int32(SocketError));
}
}
}
return Socket;
}
private:
/** Holds a flag indicating whether broadcasts will be enabled. */
bool AllowBroadcast;
/** Holds a flag indicating whether socket operations are blocking. */
bool Blocking;
/** Holds a flag indicating whether the socket should be bound. */
bool Bound;
/** Holds the IP address (and port) that the socket will be bound to. */
FIPv4Endpoint BoundEndpoint;
/** Holds the socket's debug description text. */
FString Description;
/** Holds the IP address of the interface to use for outgoing multicast datagrams. */
FIPv4Address MulticastInterface;
/** Holds the list of joined multicast groups. */
struct FMulticastGroup
{
FIPv4Address GroupAddress;
FIPv4Address InterfaceAddress;
};
TArray<FMulticastGroup> JoinedGroups;
/** Holds a flag indicating whether multicast loopback will be enabled. */
bool MulticastLoopback;
/** Holds the multicast time to live. */
uint8 MulticastTtl;
/** The desired size of the receive buffer in bytes (0 = default). */
int32 ReceiveBufferSize;
/** Holds a flag indicating whether the bound address can be reused by other sockets. */
bool Reusable;
/** The desired size of the send buffer in bytes (0 = default). */
int32 SendBufferSize;
};