Files
@ r26736:7ad626023660
Branch filter:
Location: cpp/openttd-patchpack/source/src/network/core/packet.cpp
r26736:7ad626023660
12.8 KiB
text/x-c
Update: Translations from eints
luxembourgish: 3 changes by phreeze83
hebrew: 125 changes by haimlm
luxembourgish: 3 changes by phreeze83
hebrew: 125 changes by haimlm
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 | /*
* 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.
*/
#include "../../stdafx.h"
#include "../../string_func.h"
#include "packet.h"
#include "../../safeguards.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.
* @param limit The maximum size of packets to accept.
* @param initial_read_size The initial amount of data to transfer from the socket into the
* packet. This defaults to just the required bytes to determine the
* packet's size. That default is the wanted for streams such as TCP
* as you do not want to read data of the next packet yet. For UDP
* you need to read the whole packet at once otherwise you might
* 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 limit, size_t initial_read_size) : next(nullptr), pos(0), limit(limit)
{
assert(cs != nullptr);
this->cs = cs;
this->buffer.resize(initial_read_size);
}
/**
* Creates a packet to send
* @param type The type of the packet to send
* @param limit The maximum number of bytes the packet may have. Default is COMPAT_MTU.
* Be careful of compatibility with older clients/servers when changing
* the limit as it might break things if the other side is not expecting
* much larger packets than what they support.
*/
Packet::Packet(PacketType type, size_t limit) : next(nullptr), pos(0), limit(limit), cs(nullptr)
{
/* 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);
}
/**
* Add the given Packet to the end of the queue of packets.
* @param queue The pointer to the begin of the queue.
* @param packet The packet to append to the queue.
*/
/* static */ void Packet::AddToQueue(Packet **queue, Packet *packet)
{
while (*queue != nullptr) queue = &(*queue)->next;
*queue = packet;
}
/**
* Pop the packet from the begin of the queue and set the
* begin of the queue to the second element in the queue.
* @param queue The pointer to the begin of the queue.
* @return The Packet that used to be a the begin of the queue.
*/
/* static */ Packet *Packet::PopFromQueue(Packet **queue)
{
Packet *p = *queue;
*queue = p->next;
p->next = nullptr;
return p;
}
/**
* Writes the packet size from the raw packet from packet->size
*/
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->pos = 0; // We start reading from here
this->buffer.shrink_to_fit();
}
/**
* Is it safe to write to the packet, i.e. didn't we run over the buffer?
* @param bytes_to_write The amount of bytes we want to try to write.
* @return True iff the given amount of bytes can be written to the packet.
*/
bool Packet::CanWriteToPacket(size_t bytes_to_write)
{
return this->Size() + bytes_to_write <= this->limit;
}
/*
* 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.
*/
/**
* Package a boolean in the packet.
* @param data The data to send.
*/
void Packet::Send_bool(bool data)
{
this->Send_uint8(data ? 1 : 0);
}
/**
* Package a 8 bits integer in the packet.
* @param data The data to send.
*/
void Packet::Send_uint8(uint8 data)
{
assert(this->CanWriteToPacket(sizeof(data)));
this->buffer.emplace_back(data);
}
/**
* Package a 16 bits integer in the packet.
* @param data The data to send.
*/
void Packet::Send_uint16(uint16 data)
{
assert(this->CanWriteToPacket(sizeof(data)));
this->buffer.emplace_back(GB(data, 0, 8));
this->buffer.emplace_back(GB(data, 8, 8));
}
/**
* Package a 32 bits integer in the packet.
* @param data The data to send.
*/
void Packet::Send_uint32(uint32 data)
{
assert(this->CanWriteToPacket(sizeof(data)));
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));
}
/**
* Package a 64 bits integer in the packet.
* @param data The data to send.
*/
void Packet::Send_uint64(uint64 data)
{
assert(this->CanWriteToPacket(sizeof(data)));
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));
}
/**
* 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 std::string_view data)
{
assert(this->CanWriteToPacket(data.size() + 1));
this->buffer.insert(this->buffer.end(), data.begin(), data.end());
this->buffer.emplace_back('\0');
}
/**
* Copy a sized byte buffer into the packet.
* @param data The data to send.
*/
void Packet::Send_buffer(const std::vector<byte> &data)
{
assert(this->CanWriteToPacket(sizeof(uint16) + data.size()));
this->Send_uint16((uint16)data.size());
this->buffer.insert(this->buffer.end(), data.begin(), data.end());
}
/**
* Send as many of the bytes as possible in the packet. This can mean
* that it is possible that not all bytes are sent. To cope with this
* the function returns the amount of bytes that were actually sent.
* @param begin The begin of the buffer to send.
* @param end The end of the buffer to send.
* @return The number of bytes that were added to this packet.
*/
size_t Packet::Send_bytes(const byte *begin, const byte *end)
{
size_t amount = std::min<size_t>(end - begin, this->limit - this->Size());
this->buffer.insert(this->buffer.end(), begin, begin + amount);
return amount;
}
/*
* 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?
* In case \c close_connection is true, the connection will be closed when one would
* overrun the buffer. When it is false, the connection remains untouched.
* @param bytes_to_read The amount of bytes we want to try to read.
* @param close_connection Whether to close the connection if one cannot read that amount.
* @return True if that is safe, otherwise false.
*/
bool Packet::CanReadFromPacket(size_t bytes_to_read, bool close_connection)
{
/* 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()) {
if (close_connection) this->cs->NetworkSocketHandler::MarkClosed();
return false;
}
return true;
}
/**
* Check whether the packet, given the position of the "write" pointer, has read
* enough of the packet to contain its size.
* @return True iff there is enough data in the packet to contain the packet's size.
*/
bool Packet::HasPacketSizeData() const
{
return this->pos >= sizeof(PacketSize);
}
/**
* Get the number of bytes in the packet.
* When sending a packet this is the size of the data up to that moment.
* When receiving a packet (before PrepareToRead) this is the allocated size for the data to be read.
* When reading a packet (after PrepareToRead) this is the full size of the packet.
* @return The packet's size.
*/
size_t Packet::Size() const
{
return this->buffer.size();
}
/**
* Reads the packet size from the raw packet and stores it in the packet->size
* @return True iff the packet size seems plausible.
*/
bool Packet::ParsePacketSize()
{
assert(this->cs != nullptr && this->next == nullptr);
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 (size < sizeof(PacketSize) + sizeof(PacketType) || size > this->limit) return false;
this->buffer.resize(size);
this->pos = sizeof(PacketSize);
return true;
}
/**
* Prepares the packet so it can be read
*/
void Packet::PrepareToRead()
{
/* Put the position on the right place */
this->pos = sizeof(PacketSize);
}
/**
* Get the \c PacketType from this packet.
* @return The packet type.
*/
PacketType Packet::GetPacketType() const
{
assert(this->Size() >= sizeof(PacketSize) + sizeof(PacketType));
return static_cast<PacketType>(buffer[sizeof(PacketSize)]);
}
/**
* Read a boolean from the packet.
* @return The read data.
*/
bool Packet::Recv_bool()
{
return this->Recv_uint8() != 0;
}
/**
* Read a 8 bits integer from the packet.
* @return The read data.
*/
uint8 Packet::Recv_uint8()
{
uint8 n;
if (!this->CanReadFromPacket(sizeof(n), true)) return 0;
n = this->buffer[this->pos++];
return n;
}
/**
* Read a 16 bits integer from the packet.
* @return The read data.
*/
uint16 Packet::Recv_uint16()
{
uint16 n;
if (!this->CanReadFromPacket(sizeof(n), true)) return 0;
n = (uint16)this->buffer[this->pos++];
n += (uint16)this->buffer[this->pos++] << 8;
return n;
}
/**
* Read a 32 bits integer from the packet.
* @return The read data.
*/
uint32 Packet::Recv_uint32()
{
uint32 n;
if (!this->CanReadFromPacket(sizeof(n), true)) 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;
}
/**
* Read a 64 bits integer from the packet.
* @return The read data.
*/
uint64 Packet::Recv_uint64()
{
uint64 n;
if (!this->CanReadFromPacket(sizeof(n), true)) 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;
}
/**
* Extract a sized byte buffer from the packet.
* @return The extracted buffer.
*/
std::vector<byte> Packet::Recv_buffer()
{
uint16 size = this->Recv_uint16();
if (size == 0 || !this->CanReadFromPacket(size, true)) return {};
std::vector<byte> data;
while (size-- > 0) {
data.push_back(this->buffer[this->pos++]);
}
return data;
}
/**
* Reads characters (bytes) from the packet until it finds a '\0', or reaches a
* maximum of \c length characters.
* When the '\0' has not been reached in the first \c length read characters,
* more characters are read from the packet until '\0' has been reached. However,
* these characters will not end up in the returned string.
* The length of the returned string will be at most \c length - 1 characters.
* @param length The maximum length of the string including '\0'.
* @param settings The string validation settings.
* @return The validated string.
*/
std::string Packet::Recv_string(size_t length, StringValidationSettings settings)
{
assert(length > 1);
/* Both loops with Recv_uint8 terminate when reading past the end of the
* packet as Recv_uint8 then closes the connection and returns 0. */
std::string str;
char character;
while (--length > 0 && (character = this->Recv_uint8()) != '\0') str.push_back(character);
if (length == 0) {
/* The string in the packet was longer. Read until the termination. */
while (this->Recv_uint8() != '\0') {}
}
return StrMakeValid(str, settings);
}
/**
* Get the amount of bytes that are still available for the Transfer functions.
* @return The number of bytes that still have to be transfered.
*/
size_t Packet::RemainingBytesToTransfer() const
{
return this->Size() - this->pos;
}
|