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/* $Id$ */
/*
* This file is part of OpenTTD.
* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file packet.cpp Basic functions to create, fill and read packets.
*/
#ifdef ENABLE_NETWORK
#include "../../stdafx.h"
#include "../../string_func.h"
#include "packet.h"
/**
* Create a packet that is used to read from a network socket
* @param cs the socket handler associated with the socket we are reading from
*/
Packet::Packet(NetworkSocketHandler *cs)
{
assert(cs != NULL);
this->cs = cs;
this->next = NULL;
this->pos = 0; // We start reading from here
this->size = 0;
}
/**
* Creates a packet to send
* @param type of the packet to send
*/
Packet::Packet(PacketType type)
{
this->cs = NULL;
this->next = NULL;
/* Skip the size so we can write that in before sending the packet */
this->pos = 0;
this->size = sizeof(PacketSize);
this->buffer[this->size++] = type;
}
/**
* Writes the packet size from the raw packet from packet->size
*/
void Packet::PrepareToSend()
{
assert(this->cs == NULL && this->next == NULL);
this->buffer[0] = GB(this->size, 0, 8);
this->buffer[1] = GB(this->size, 8, 8);
this->pos = 0; // We start reading from here
}
/**
* The next couple of functions make sure we can send
* uint8, uint16, uint32 and uint64 endian-safe
* over the network. The least significant bytes are
* sent first.
*
* So 0x01234567 would be sent as 67 45 23 01.
*
* A bool is sent as a uint8 where zero means false
* and non-zero means true.
*/
void Packet::Send_bool(bool data)
{
this->Send_uint8(data ? 1 : 0);
}
void Packet::Send_uint8(uint8 data)
{
assert(this->size < sizeof(this->buffer) - sizeof(data));
this->buffer[this->size++] = data;
}
void Packet::Send_uint16(uint16 data)
{
assert(this->size < sizeof(this->buffer) - sizeof(data));
this->buffer[this->size++] = GB(data, 0, 8);
this->buffer[this->size++] = GB(data, 8, 8);
}
void Packet::Send_uint32(uint32 data)
{
assert(this->size < sizeof(this->buffer) - 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);
}
void Packet::Send_uint64(uint64 data)
{
assert(this->size < sizeof(this->buffer) - 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);
}
/**
* Sends a string over the network. It sends out
* the string + '\0'. No size-byte or something.
* @param data the string to send
*/
void Packet::Send_string(const char *data)
{
assert(data != NULL);
/* The <= *is* valid due to the fact that we are comparing sizes and not the index. */
assert(this->size + strlen(data) + 1 <= sizeof(this->buffer));
while ((this->buffer[this->size++] = *data++) != '\0') {}
}
/**
* Receiving commands
* Again, the next couple of functions are endian-safe
* see the comment before Send_bool for more info.
*/
/** Is it safe to read from the packet, i.e. didn't we run over the buffer ? */
bool Packet::CanReadFromPacket(uint bytes_to_read)
{
/* Don't allow reading from a quit client/client who send bad data */
if (this->cs->HasClientQuit()) return false;
/* Check if variable is within packet-size */
if (this->pos + bytes_to_read > this->size) {
this->cs->NetworkSocketHandler::CloseConnection();
return false;
}
return true;
}
/**
* Reads the packet size from the raw packet and stores it in the packet->size
*/
void Packet::ReadRawPacketSize()
{
assert(this->cs != NULL && this->next == NULL);
this->size = (PacketSize)this->buffer[0];
this->size += (PacketSize)this->buffer[1] << 8;
}
/**
* Prepares the packet so it can be read
*/
void Packet::PrepareToRead()
{
this->ReadRawPacketSize();
/* Put the position on the right place */
this->pos = sizeof(PacketSize);
}
bool Packet::Recv_bool()
{
return this->Recv_uint8() != 0;
}
uint8 Packet::Recv_uint8()
{
uint8 n;
if (!this->CanReadFromPacket(sizeof(n))) return 0;
n = this->buffer[this->pos++];
return n;
}
uint16 Packet::Recv_uint16()
{
uint16 n;
if (!this->CanReadFromPacket(sizeof(n))) return 0;
n = (uint16)this->buffer[this->pos++];
n += (uint16)this->buffer[this->pos++] << 8;
return n;
}
uint32 Packet::Recv_uint32()
{
uint32 n;
if (!this->CanReadFromPacket(sizeof(n))) return 0;
n = (uint32)this->buffer[this->pos++];
n += (uint32)this->buffer[this->pos++] << 8;
n += (uint32)this->buffer[this->pos++] << 16;
n += (uint32)this->buffer[this->pos++] << 24;
return n;
}
uint64 Packet::Recv_uint64()
{
uint64 n;
if (!this->CanReadFromPacket(sizeof(n))) return 0;
n = (uint64)this->buffer[this->pos++];
n += (uint64)this->buffer[this->pos++] << 8;
n += (uint64)this->buffer[this->pos++] << 16;
n += (uint64)this->buffer[this->pos++] << 24;
n += (uint64)this->buffer[this->pos++] << 32;
n += (uint64)this->buffer[this->pos++] << 40;
n += (uint64)this->buffer[this->pos++] << 48;
n += (uint64)this->buffer[this->pos++] << 56;
return n;
}
/** Reads a string till it finds a '\0' in the stream */
void Packet::Recv_string(char *buffer, size_t size, bool allow_newlines)
{
PacketSize pos;
char *bufp = buffer;
const char *last = buffer + size - 1;
/* Don't allow reading from a closed socket */
if (cs->HasClientQuit()) return;
pos = this->pos;
while (--size > 0 && pos < this->size && (*buffer++ = this->buffer[pos++]) != '\0') {}
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++;
pos++;
}
this->pos = pos;
str_validate(bufp, last, allow_newlines);
}
#endif /* ENABLE_NETWORK */
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