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Fix mishandling of PACKET_SERVER_MAP_BEGIN queuing at server

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This could result in broken packet framing in the TCP stream
This commit is contained in:
Jonathan G Rennison
2021-05-21 00:58:24 +01:00
parent 7c706923f8
commit 7677d2d01a
3 changed files with 25 additions and 18 deletions
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23
src/network/network_server.cpp
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@@ -63,7 +63,7 @@ struct PacketWriter : SaveFilter {
std::unique_ptr<Packet> current; ///< The packet we're currently writing to.
size_t total_size; ///< Total size of the compressed savegame.
std::vector<std::unique_ptr<Packet>> packets; ///< Packet queue of the savegame; send these "slowly" to the client.
std::vector<std::unique_ptr<Packet>> prepend_packets; ///< Packet queue of the savegame; send these "slowly" to the client.
std::unique_ptr<Packet> map_size_packet; ///< Map size packet, fast tracked to the client
std::mutex mutex; ///< Mutex for making threaded saving safe.
std::condition_variable exit_sig; ///< Signal for threaded destruction of this packet writer.
@@ -85,7 +85,7 @@ struct PacketWriter : SaveFilter {
/* This must all wait until the Destroy function is called. */
this->packets.clear();
this->prepend_packets.clear();
this->map_size_packet.reset();
this->current.reset();
}
@@ -125,8 +125,9 @@ struct PacketWriter : SaveFilter {
{
std::lock_guard<std::mutex> lock(this->mutex);
for (auto &p : this->prepend_packets) {
socket->SendPrependPacket(std::move(p));
if (this->map_size_packet) {
/* Don't queue the PACKET_SERVER_MAP_SIZE before the corresponding PACKET_SERVER_MAP_BEGIN */
socket->SendPrependPacket(std::move(this->map_size_packet), PACKET_SERVER_MAP_BEGIN);
}
bool last_packet = false;
for (auto &p : this->packets) {
@@ -134,7 +135,6 @@ struct PacketWriter : SaveFilter {
socket->SendPacket(std::move(p));
}
this->prepend_packets.clear();
this->packets.clear();
return last_packet;
@@ -148,14 +148,6 @@ struct PacketWriter : SaveFilter {
this->packets.push_back(std::move(this->current));
}
/** Prepend the current packet to the queue. */
void PrependQueue()
{
if (this->current == nullptr) return;
this->prepend_packets.push_back(std::move(this->current));
}
void Write(byte *buf, size_t size) override
{
/* We want to abort the saving when the socket is closed. */
@@ -194,9 +186,8 @@ struct PacketWriter : SaveFilter {
this->AppendQueue();
/* Fast-track the size to the client. */
this->current.reset(new Packet(PACKET_SERVER_MAP_SIZE, SHRT_MAX));
this->current->Send_uint32((uint32)this->total_size);
this->PrependQueue();
this->map_size_packet.reset(new Packet(PACKET_SERVER_MAP_SIZE, SHRT_MAX));
this->map_size_packet->Send_uint32((uint32)this->total_size);
}
};