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Packets handling in UdpSocket is now more robust

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git-svn-id: https://sfml.svn.sourceforge.net/svnroot/sfml/branches/sfml2@1490 4e206d99-4929-0410-ac5d-dfc041789085
This commit is contained in:
LaurentGom 2010-04-05 14:06:37 +00:00
parent 507f467390
commit 41f09975ab
3 changed files with 76 additions and 84 deletions
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23
include/SFML/Network/UdpSocket.hpp
View File

@ -44,6 +44,14 @@ class SFML_API UdpSocket : public Socket
{
public :
////////////////////////////////////////////////////////////
// Constants
////////////////////////////////////////////////////////////
enum
{
MaxDatagramSize = 65507 ///< The maximum number of bytes that can be sent in a single UDP datagram
};
////////////////////////////////////////////////////////////
/// \brief Default constructor
///
@ -96,6 +104,10 @@ public :
////////////////////////////////////////////////////////////
/// \brief Send raw data to a remote peer
///
/// Make sure that \a size is not greater than
/// UdpSocket::MaxDatagramSize, otherwise this function will
/// fail and no data will be sent.
///
/// \param data Pointer to the sequence of bytes to send
/// \param size Number of bytes to send
/// \param remoteAddress Address of the receiver
@ -113,6 +125,10 @@ public :
///
/// In blocking mode, this function will wait until some
/// bytes are actually received.
/// Be careful to use a buffer which is large enough for
/// the data that you intend to receive, if it is too small
/// then an error will be returned and *all* the data will
/// be lost.
///
/// \param data Pointer to the array to fill with the received bytes
/// \param size Maximum number of bytes that can be received
@ -130,6 +146,11 @@ public :
////////////////////////////////////////////////////////////
/// \brief Send a formatted packet of data to a remote peer
///
/// Unlike the other version of Send, this function can accept
/// data sizes greater than UdpSocket::MaxDatagramSize.
/// If necessary, the data will be split and sent in multiple
/// datagrams.
///
/// \param packet Packet to send
/// \param remoteAddress Address of the receiver
/// \param remotePort Port of the receiver to send the data to
@ -146,6 +167,8 @@ public :
///
/// In blocking mode, this function will wait until the whole packet
/// has been received.
/// Warning: this functon doesn't properly handle mixed data
/// received from multiple peers.
///
/// \param packet Packet to fill with the received data
/// \param remoteAddress Address of the peer that sent the data

14
src/SFML/Network/TcpSocket.cpp
View File

@ -208,7 +208,7 @@ Socket::Status TcpSocket::Send(const char* data, std::size_t size)
// Check the parameters
if (!data || (size == 0))
{
Err() << "Cannot send data over the network (invalid parameters)" << std::endl;
Err() << "Cannot send data over the network (no data to send)" << std::endl;
return Error;
}
@ -221,7 +221,7 @@ Socket::Status TcpSocket::Send(const char* data, std::size_t size)
sent = send(GetHandle(), data + length, sizeToSend - length, 0);
// Check for errors
if (sent <= 0)
if (sent < 0)
return priv::SocketImpl::GetErrorStatus();
}
@ -235,10 +235,10 @@ Socket::Status TcpSocket::Receive(char* data, std::size_t size, std::size_t& rec
// First clear the variables to fill
received = 0;
// Check the parameters
if (!data || (size == 0))
// Check the destination buffer
if (!data)
{
Err() << "Cannot receive data from the network (invalid parameters)" << std::endl;
Err() << "Cannot receive data from the network (the destination buffer is invalid)" << std::endl;
return Error;
}
@ -265,6 +265,10 @@ Socket::Status TcpSocket::Receive(char* data, std::size_t size, std::size_t& rec
////////////////////////////////////////////////////////////
Socket::Status TcpSocket::Send(Packet& packet)
{
// TCP is a stream protocol, it doesn't preserve messages boundaries.
// This means that we have to send the packet size first, so that the
// receiver knows the actual end of the packet in the data stream.
// Get the data to send from the packet
std::size_t size = 0;
const char* data = packet.OnSend(size);

115
src/SFML/Network/UdpSocket.cpp
View File

@ -95,28 +95,23 @@ Socket::Status UdpSocket::Send(const char* data, std::size_t size, const IpAddre
// Create the internal socket if it doesn't exist
Create();
// Check the parameters
if (!data || (size == 0))
// Make sure that all the data will fit in one datagram
if (size > MaxDatagramSize)
{
Err() << "Cannot send data over the network (invalid parameters)" << std::endl;
Err() << "Cannot send data over the network "
<< "(the number of bytes to send is greater than sf::UdpSocket::MaxDatagramSize)" << std::endl;
return Error;
}
// Build the target address
sockaddr_in address = priv::SocketImpl::CreateAddress(remoteAddress.ToInteger(), remotePort);
// Loop until every byte has been sent
int sent = 0;
int sizeToSend = static_cast<int>(size);
for (int length = 0; length < sizeToSend; length += sent)
{
// Send a chunk of data
sent = sendto(GetHandle(), data + length, sizeToSend - length, 0, reinterpret_cast<sockaddr*>(&address), sizeof(address));
// Send the data (unlike TCP, all the data is always sent in one call)
int sent = sendto(GetHandle(), data, size, 0, reinterpret_cast<sockaddr*>(&address), sizeof(address));
// Check for errors
if (sent <= 0)
if (sent < 0)
return priv::SocketImpl::GetErrorStatus();
}
return Done;
}
@ -130,10 +125,10 @@ Socket::Status UdpSocket::Receive(char* data, std::size_t size, std::size_t& rec
remoteAddress = IpAddress();
remotePort = 0;
// Check the parameters
if (!data || (size == 0))
// Check the destination buffer
if (!data)
{
Err() << "Cannot receive data from the network (invalid parameters)" << std::endl;
Err() << "Cannot receive data from the network (the destination buffer is invalid)" << std::endl;
return Error;
}
@ -145,7 +140,7 @@ Socket::Status UdpSocket::Receive(char* data, std::size_t size, std::size_t& rec
int sizeReceived = recvfrom(GetHandle(), data, static_cast<int>(size), 0, reinterpret_cast<sockaddr*>(&address), &addressSize);
// Check for errors
if (sizeReceived <= 0)
if (sizeReceived < 0)
return priv::SocketImpl::GetErrorStatus();
// Fill the sender informations
@ -160,28 +155,30 @@ Socket::Status UdpSocket::Receive(char* data, std::size_t size, std::size_t& rec
////////////////////////////////////////////////////////////
Socket::Status UdpSocket::Send(Packet& packet, const IpAddress& remoteAddress, unsigned short remotePort)
{
// As the UDP protocol preserves datagrams boundaries, we don't have to
// send the packet size first (it would even be a potential source of bug, if
// that size arrives corrupted), but we must split the packet into multiple
// pieces if data size is greater than the maximum datagram size.
// Get the data to send from the packet
std::size_t size = 0;
const char* data = packet.OnSend(size);
// First send the packet size
Uint32 packetSize = htonl(static_cast<unsigned long>(size));
Status status = Send(reinterpret_cast<const char*>(&packetSize), sizeof(packetSize), remoteAddress, remotePort);
// Make sure that the size was properly sent
// If size is greater than MaxDatagramSize, the data must be split into multiple datagrams
while (size >= MaxDatagramSize)
{
Status status = Send(data, MaxDatagramSize, remoteAddress, remotePort);
if (status != Done)
return status;
// Finally send the packet data
if (packetSize > 0)
{
data += MaxDatagramSize;
size -= MaxDatagramSize;
}
// It is important to send a final datagram with a size < MaxDatagramSize,
// even if it is zero, to mark the end of the packet
return Send(data, size, remoteAddress, remotePort);
}
else
{
return Done;
}
}
////////////////////////////////////////////////////////////
@ -192,60 +189,28 @@ Socket::Status UdpSocket::Receive(Packet& packet, IpAddress& remoteAddress, unsi
remoteAddress = IpAddress();
remotePort = 0;
// We start by getting the size of the incoming packet
Uint32 packetSize = 0;
// Receive datagrams
std::size_t received = 0;
if (myPendingPacket.SizeReceived < sizeof(myPendingPacket.Size))
do
{
// Loop until we've received the entire size of the packet
// (even a 4 bytes variable may be received in more than one call)
while (myPendingPacket.SizeReceived < sizeof(myPendingPacket.Size))
{
char* data = reinterpret_cast<char*>(&myPendingPacket.Size) + myPendingPacket.SizeReceived;
std::size_t size = sizeof(myPendingPacket.Size) - myPendingPacket.SizeReceived;
Status status = Receive(data, size, received, remoteAddress, remotePort);
myPendingPacket.SizeReceived += received;
// Make room in the data buffer for a new datagram
std::size_t size = myPendingPacket.Data.size();
myPendingPacket.Data.resize(size + MaxDatagramSize);
char* data = &myPendingPacket.Data[0] + size;
// Receive the datagram
Status status = Receive(data, MaxDatagramSize, received, remoteAddress, remotePort);
// Check for errors
if (status != Done)
return status;
}
// The packet size has been fully received
packetSize = ntohl(myPendingPacket.Size);
}
else
{
// The packet size has already been received in a previous call
packetSize = ntohl(myPendingPacket.Size);
}
// Use another address instance for receiving the packet data,
// chunks of data coming from a different sender will be discarded (and lost...)
IpAddress currentSender;
unsigned short currentPort;
// Loop until we receive all the packet data
char buffer[1024];
while (myPendingPacket.Data.size() < packetSize)
{
// Receive a chunk of data
std::size_t sizeToGet = std::min(static_cast<std::size_t>(packetSize - myPendingPacket.Data.size()), sizeof(buffer));
Status status = Receive(buffer, sizeToGet, received, currentSender, currentPort);
if (status != Done)
return status;
// Append it into the packet
if ((currentSender == remoteAddress) && (currentPort == remotePort) && (received > 0))
{
myPendingPacket.Data.resize(myPendingPacket.Data.size() + received);
char* begin = &myPendingPacket.Data[0] + myPendingPacket.Data.size() - received;
memcpy(begin, buffer, received);
}
}
while (received == MaxDatagramSize);
// We have received all the packet data: we can copy it to the user packet
if (!myPendingPacket.Data.empty())
packet.OnReceive(&myPendingPacket.Data[0], myPendingPacket.Data.size());
std::size_t actualSize = myPendingPacket.Data.size() - MaxDatagramSize + received;
if (actualSize > 0)
packet.OnReceive(&myPendingPacket.Data[0], actualSize);
// Clear the pending packet data
myPendingPacket = PendingPacket();