Skip to content

Commit

Permalink
Codechange: use std::vector instead of a fixed size array for Packets
Browse files Browse the repository at this point in the history
  • Loading branch information
@rubidium42
rubidium42 committed Apr 22, 2021
1 parent 477ce73 commit 6e187cb
Show file tree
Hide file tree
Showing 2 changed files with 44 additions and 70 deletions.
98 changes: 39 additions & 59 deletions src/network/core/packet.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,39 +27,23 @@
* loose some the data of the packet, so there you pass the maximum
* size for the packet you expect from the network.
*/
Packet::Packet(NetworkSocketHandler *cs, size_t initial_read_size)
Packet::Packet(NetworkSocketHandler *cs, size_t initial_read_size) : next(nullptr), pos(0)
{
assert(cs != nullptr);

this->cs = cs;
this->next = nullptr;
this->pos = 0; // We start reading from here
this->size = static_cast<int>(initial_read_size);
this->buffer = MallocT<byte>(SEND_MTU);
this->cs = cs;
this->buffer.resize(initial_read_size);
}

/**
* Creates a packet to send
* @param type of the packet to send
*/
Packet::Packet(PacketType type)
Packet::Packet(PacketType type) : next(nullptr), pos(0), cs(nullptr)
{
this->cs = nullptr;
this->next = nullptr;

/* Skip the size so we can write that in before sending the packet */
this->pos = 0;
this->size = sizeof(PacketSize);
this->buffer = MallocT<byte>(SEND_MTU);
this->buffer[this->size++] = type;
}

/**
* Free the buffer of this packet.
*/
Packet::~Packet()
{
free(this->buffer);
/* Allocate space for the the size so we can write that in just before sending the packet. */
this->Send_uint16(0);
this->Send_uint8(type);
}

/**
Expand Down Expand Up @@ -95,15 +79,11 @@ void Packet::PrepareToSend()
{
assert(this->cs == nullptr && this->next == nullptr);

this->buffer[0] = GB(this->size, 0, 8);
this->buffer[1] = GB(this->size, 8, 8);
this->buffer[0] = GB(this->Size(), 0, 8);
this->buffer[1] = GB(this->Size(), 8, 8);

this->pos = 0; // We start reading from here

/* Reallocate the packet as in 99+% of the times we send at most 25 bytes and
* keeping the other 1400+ bytes wastes memory, especially when someone tries
* to do a denial of service attack! */
this->buffer = ReallocT(this->buffer, this->size);
this->buffer.shrink_to_fit();
}

/**
Expand All @@ -113,7 +93,7 @@ void Packet::PrepareToSend()
*/
bool Packet::CanWriteToPacket(size_t bytes_to_write)
{
return this->size + bytes_to_write < SEND_MTU;
return this->Size() + bytes_to_write < SEND_MTU;
}

/*
Expand Down Expand Up @@ -144,7 +124,7 @@ void Packet::Send_bool(bool data)
void Packet::Send_uint8(uint8 data)
{
assert(this->CanWriteToPacket(sizeof(data)));
this->buffer[this->size++] = data;
this->buffer.emplace_back(data);
}

/**
Expand All @@ -154,8 +134,8 @@ void Packet::Send_uint8(uint8 data)
void Packet::Send_uint16(uint16 data)
{
assert(this->CanWriteToPacket(sizeof(data)));
this->buffer[this->size++] = GB(data, 0, 8);
this->buffer[this->size++] = GB(data, 8, 8);
this->buffer.emplace_back(GB(data, 0, 8));
this->buffer.emplace_back(GB(data, 8, 8));
}

/**
Expand All @@ -165,10 +145,10 @@ void Packet::Send_uint16(uint16 data)
void Packet::Send_uint32(uint32 data)
{
assert(this->CanWriteToPacket(sizeof(data)));
this->buffer[this->size++] = GB(data, 0, 8);
this->buffer[this->size++] = GB(data, 8, 8);
this->buffer[this->size++] = GB(data, 16, 8);
this->buffer[this->size++] = GB(data, 24, 8);
this->buffer.emplace_back(GB(data, 0, 8));
this->buffer.emplace_back(GB(data, 8, 8));
this->buffer.emplace_back(GB(data, 16, 8));
this->buffer.emplace_back(GB(data, 24, 8));
}

/**
Expand All @@ -178,14 +158,14 @@ void Packet::Send_uint32(uint32 data)
void Packet::Send_uint64(uint64 data)
{
assert(this->CanWriteToPacket(sizeof(data)));
this->buffer[this->size++] = GB(data, 0, 8);
this->buffer[this->size++] = GB(data, 8, 8);
this->buffer[this->size++] = GB(data, 16, 8);
this->buffer[this->size++] = GB(data, 24, 8);
this->buffer[this->size++] = GB(data, 32, 8);
this->buffer[this->size++] = GB(data, 40, 8);
this->buffer[this->size++] = GB(data, 48, 8);
this->buffer[this->size++] = GB(data, 56, 8);
this->buffer.emplace_back(GB(data, 0, 8));
this->buffer.emplace_back(GB(data, 8, 8));
this->buffer.emplace_back(GB(data, 16, 8));
this->buffer.emplace_back(GB(data, 24, 8));
this->buffer.emplace_back(GB(data, 32, 8));
this->buffer.emplace_back(GB(data, 40, 8));
this->buffer.emplace_back(GB(data, 48, 8));
this->buffer.emplace_back(GB(data, 56, 8));
}

/**
Expand All @@ -198,7 +178,7 @@ void Packet::Send_string(const char *data)
assert(data != nullptr);
/* Length of the string + 1 for the '\0' termination. */
assert(this->CanWriteToPacket(strlen(data) + 1));
while ((this->buffer[this->size++] = *data++) != '\0') {}
while (this->buffer.emplace_back(*data++) != '\0') {}
}

/**
Expand All @@ -211,9 +191,8 @@ void Packet::Send_string(const char *data)
*/
size_t Packet::Send_bytes(const byte *begin, const byte *end)
{
size_t amount = std::min<size_t>(end - begin, SEND_MTU - this->size);
memcpy(this->buffer + this->size, begin, amount);
this->size += static_cast<PacketSize>(amount);
size_t amount = std::min<size_t>(end - begin, SEND_MTU - this->Size());
this->buffer.insert(this->buffer.end(), begin, begin + amount);
return amount;
}

Expand All @@ -238,7 +217,7 @@ bool Packet::CanReadFromPacket(size_t bytes_to_read, bool close_connection)
if (this->cs->HasClientQuit()) return false;

/* Check if variable is within packet-size */
if (this->pos + bytes_to_read > this->size) {
if (this->pos + bytes_to_read > this->Size()) {
if (close_connection) this->cs->NetworkSocketHandler::CloseConnection();
return false;
}
Expand All @@ -265,7 +244,7 @@ bool Packet::HasPacketSizeData() const
*/
size_t Packet::Size() const
{
return this->size;
return this->buffer.size();
}

/**
Expand All @@ -275,14 +254,15 @@ size_t Packet::Size() const
bool Packet::ParsePacketSize()
{
assert(this->cs != nullptr && this->next == nullptr);
this->size = (PacketSize)this->buffer[0];
this->size += (PacketSize)this->buffer[1] << 8;
size_t size = (size_t)this->buffer[0];
size += (size_t)this->buffer[1] << 8;

/* If the size of the packet is less than the bytes required for the size and type of
* the packet, or more than the allowed limit, then something is wrong with the packet.
* In those cases the packet can generally be regarded as containing garbage data. */
if (this->size < sizeof(PacketSize) + sizeof(PacketType) || this->size > SEND_MTU) return false;
if (size < sizeof(PacketSize) + sizeof(PacketType) || size > SEND_MTU) return false;

this->buffer.resize(size);
this->pos = sizeof(PacketSize);
return true;
}
Expand Down Expand Up @@ -398,13 +378,13 @@ void Packet::Recv_string(char *buffer, size_t size, StringValidationSettings set
if (cs->HasClientQuit()) return;

pos = this->pos;
while (--size > 0 && pos < this->size && (*buffer++ = this->buffer[pos++]) != '\0') {}
while (--size > 0 && pos < this->Size() && (*buffer++ = this->buffer[pos++]) != '\0') {}

if (size == 0 || pos == this->size) {
if (size == 0 || pos == this->Size()) {
*buffer = '\0';
/* If size was sooner to zero then the string in the stream
* skip till the \0, so than packet can be read out correctly for the rest */
while (pos < this->size && this->buffer[pos] != '\0') pos++;
while (pos < this->Size() && this->buffer[pos] != '\0') pos++;
pos++;
}
this->pos = pos;
Expand All @@ -418,5 +398,5 @@ void Packet::Recv_string(char *buffer, size_t size, StringValidationSettings set
*/
size_t Packet::RemainingBytesToTransfer() const
{
return this->size - this->pos;
return this->Size() - this->pos;
}
16 changes: 5 additions & 11 deletions src/network/core/packet.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -43,23 +43,17 @@ struct Packet {
private:
/** The next packet. Used for queueing packets before sending. */
Packet *next;
/**
* The size of the whole packet for received packets. For packets
* that will be sent, the value is filled in just before the
* actual transmission.
*/
PacketSize size;
/** The current read/write position in the packet */
PacketSize pos;
/** The buffer of this packet, of basically variable length up to SEND_MTU. */
byte *buffer;
/** The buffer of this packet. */
std::vector<byte> buffer;

/** Socket we're associated with. */
NetworkSocketHandler *cs;

public:
Packet(NetworkSocketHandler *cs, size_t initial_read_size = sizeof(PacketSize));
Packet(PacketType type);
~Packet();

static void AddToQueue(Packet **queue, Packet *packet);
static Packet *PopFromQueue(Packet **queue);
Expand Down Expand Up @@ -116,7 +110,7 @@ struct Packet {
if (amount == 0) return 0;

/* Making buffer a char means casting a lot in the Recv/Send functions. */
const char *output_buffer = reinterpret_cast<const char*>(this->buffer + this->pos);
const char *output_buffer = reinterpret_cast<const char*>(this->buffer.data() + this->pos);
ssize_t bytes = transfer_function(destination, output_buffer, static_cast<A>(amount), std::forward<Args>(args)...);
if (bytes > 0) this->pos += bytes;
return bytes;
Expand Down Expand Up @@ -179,7 +173,7 @@ struct Packet {
if (amount == 0) return 0;

/* Making buffer a char means casting a lot in the Recv/Send functions. */
char *input_buffer = reinterpret_cast<char*>(this->buffer + this->pos);
char *input_buffer = reinterpret_cast<char*>(this->buffer.data() + this->pos);
ssize_t bytes = transfer_function(source, input_buffer, static_cast<A>(amount), std::forward<Args>(args)...);
if (bytes > 0) this->pos += bytes;
return bytes;
Expand Down

0 comments on commit 6e187cb

Please sign in to comment.