444 lines
15 KiB
C++
444 lines
15 KiB
C++
/*
|
|
* Authored by Alex Hultman, 2018-2019.
|
|
* Intellectual property of third-party.
|
|
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#ifndef UWS_WEBSOCKETPROTOCOL_H
|
|
#define UWS_WEBSOCKETPROTOCOL_H
|
|
|
|
#include <cstdint>
|
|
#include <cstring>
|
|
#include <cstdlib>
|
|
|
|
namespace uWS {
|
|
|
|
enum OpCode : unsigned char {
|
|
TEXT = 1,
|
|
BINARY = 2,
|
|
CLOSE = 8,
|
|
PING = 9,
|
|
PONG = 10
|
|
};
|
|
|
|
enum {
|
|
CLIENT,
|
|
SERVER
|
|
};
|
|
|
|
// 24 bytes perfectly
|
|
template <bool isServer>
|
|
struct WebSocketState {
|
|
public:
|
|
static const unsigned int SHORT_MESSAGE_HEADER = isServer ? 6 : 2;
|
|
static const unsigned int MEDIUM_MESSAGE_HEADER = isServer ? 8 : 4;
|
|
static const unsigned int LONG_MESSAGE_HEADER = isServer ? 14 : 10;
|
|
|
|
// 16 bytes
|
|
struct State {
|
|
unsigned int wantsHead : 1;
|
|
unsigned int spillLength : 4;
|
|
int opStack : 2; // -1, 0, 1
|
|
unsigned int lastFin : 1;
|
|
|
|
// 15 bytes
|
|
unsigned char spill[LONG_MESSAGE_HEADER - 1];
|
|
OpCode opCode[2];
|
|
|
|
State() {
|
|
wantsHead = true;
|
|
spillLength = 0;
|
|
opStack = -1;
|
|
lastFin = true;
|
|
}
|
|
|
|
} state;
|
|
|
|
// 8 bytes
|
|
unsigned int remainingBytes = 0;
|
|
char mask[isServer ? 4 : 1];
|
|
};
|
|
|
|
namespace protocol {
|
|
|
|
template <typename T>
|
|
T bit_cast(char *c) {
|
|
T val;
|
|
memcpy(&val, c, sizeof(T));
|
|
return val;
|
|
}
|
|
|
|
/* Byte swap for little-endian systems */
|
|
template <typename T>
|
|
T cond_byte_swap(T value) {
|
|
uint32_t endian_test = 1;
|
|
if (*((char *)&endian_test)) {
|
|
union {
|
|
T i;
|
|
uint8_t b[sizeof(T)];
|
|
} src = { value }, dst;
|
|
|
|
for (unsigned int i = 0; i < sizeof(value); i++) {
|
|
dst.b[i] = src.b[sizeof(value) - 1 - i];
|
|
}
|
|
|
|
return dst.i;
|
|
}
|
|
return value;
|
|
}
|
|
|
|
// Based on utf8_check.c by Markus Kuhn, 2005
|
|
// https://www.cl.cam.ac.uk/~mgk25/ucs/utf8_check.c
|
|
// Optimized for predominantly 7-bit content by Alex Hultman, 2016
|
|
// Licensed as Zlib, like the rest of this project
|
|
static bool isValidUtf8(unsigned char *s, size_t length)
|
|
{
|
|
for (unsigned char *e = s + length; s != e; ) {
|
|
if (s + 4 <= e) {
|
|
uint32_t tmp;
|
|
memcpy(&tmp, s, 4);
|
|
if ((tmp & 0x80808080) == 0) {
|
|
s += 4;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
while (!(*s & 0x80)) {
|
|
if (++s == e) {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
if ((s[0] & 0x60) == 0x40) {
|
|
if (s + 1 >= e || (s[1] & 0xc0) != 0x80 || (s[0] & 0xfe) == 0xc0) {
|
|
return false;
|
|
}
|
|
s += 2;
|
|
} else if ((s[0] & 0xf0) == 0xe0) {
|
|
if (s + 2 >= e || (s[1] & 0xc0) != 0x80 || (s[2] & 0xc0) != 0x80 ||
|
|
(s[0] == 0xe0 && (s[1] & 0xe0) == 0x80) || (s[0] == 0xed && (s[1] & 0xe0) == 0xa0)) {
|
|
return false;
|
|
}
|
|
s += 3;
|
|
} else if ((s[0] & 0xf8) == 0xf0) {
|
|
if (s + 3 >= e || (s[1] & 0xc0) != 0x80 || (s[2] & 0xc0) != 0x80 || (s[3] & 0xc0) != 0x80 ||
|
|
(s[0] == 0xf0 && (s[1] & 0xf0) == 0x80) || (s[0] == 0xf4 && s[1] > 0x8f) || s[0] > 0xf4) {
|
|
return false;
|
|
}
|
|
s += 4;
|
|
} else {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
struct CloseFrame {
|
|
uint16_t code;
|
|
char *message;
|
|
size_t length;
|
|
};
|
|
|
|
static inline CloseFrame parseClosePayload(char *src, size_t length) {
|
|
CloseFrame cf = {};
|
|
if (length >= 2) {
|
|
memcpy(&cf.code, src, 2);
|
|
cf = {cond_byte_swap<uint16_t>(cf.code), src + 2, length - 2};
|
|
if (cf.code < 1000 || cf.code > 4999 || (cf.code > 1011 && cf.code < 4000) ||
|
|
(cf.code >= 1004 && cf.code <= 1006) || !isValidUtf8((unsigned char *) cf.message, cf.length)) {
|
|
return {};
|
|
}
|
|
}
|
|
return cf;
|
|
}
|
|
|
|
static inline size_t formatClosePayload(char *dst, uint16_t code, const char *message, size_t length) {
|
|
if (code) {
|
|
code = cond_byte_swap<uint16_t>(code);
|
|
memcpy(dst, &code, 2);
|
|
/* It is invalid to pass nullptr to memcpy, even though length is 0 */
|
|
if (message) {
|
|
memcpy(dst + 2, message, length);
|
|
}
|
|
return length + 2;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static inline size_t messageFrameSize(size_t messageSize) {
|
|
if (messageSize < 126) {
|
|
return 2 + messageSize;
|
|
} else if (messageSize <= UINT16_MAX) {
|
|
return 4 + messageSize;
|
|
}
|
|
return 10 + messageSize;
|
|
}
|
|
|
|
enum {
|
|
SND_CONTINUATION = 1,
|
|
SND_NO_FIN = 2,
|
|
SND_COMPRESSED = 64
|
|
};
|
|
|
|
template <bool isServer>
|
|
static inline size_t formatMessage(char *dst, const char *src, size_t length, OpCode opCode, size_t reportedLength, bool compressed) {
|
|
size_t messageLength;
|
|
size_t headerLength;
|
|
if (reportedLength < 126) {
|
|
headerLength = 2;
|
|
dst[1] = (char) reportedLength;
|
|
} else if (reportedLength <= UINT16_MAX) {
|
|
headerLength = 4;
|
|
dst[1] = 126;
|
|
uint16_t tmp = cond_byte_swap<uint16_t>((uint16_t) reportedLength);
|
|
memcpy(&dst[2], &tmp, sizeof(uint16_t));
|
|
} else {
|
|
headerLength = 10;
|
|
dst[1] = 127;
|
|
uint64_t tmp = cond_byte_swap<uint64_t>((uint64_t) reportedLength);
|
|
memcpy(&dst[2], &tmp, sizeof(uint64_t));
|
|
}
|
|
|
|
int flags = 0;
|
|
dst[0] = (char) ((flags & SND_NO_FIN ? 0 : 128) | (compressed ? SND_COMPRESSED : 0));
|
|
if (!(flags & SND_CONTINUATION)) {
|
|
dst[0] |= (char) opCode;
|
|
}
|
|
|
|
char mask[4];
|
|
if (!isServer) {
|
|
dst[1] |= 0x80;
|
|
uint32_t random = rand();
|
|
memcpy(mask, &random, 4);
|
|
memcpy(dst + headerLength, &random, 4);
|
|
headerLength += 4;
|
|
}
|
|
|
|
messageLength = headerLength + length;
|
|
memcpy(dst + headerLength, src, length);
|
|
|
|
if (!isServer) {
|
|
|
|
// overwrites up to 3 bytes outside of the given buffer!
|
|
//WebSocketProtocol<isServer>::unmaskInplace(dst + headerLength, dst + headerLength + length, mask);
|
|
|
|
// this is not optimal
|
|
char *start = dst + headerLength;
|
|
char *stop = start + length;
|
|
int i = 0;
|
|
while (start != stop) {
|
|
(*start++) ^= mask[i++ % 4];
|
|
}
|
|
}
|
|
return messageLength;
|
|
}
|
|
|
|
}
|
|
|
|
// essentially this is only a parser
|
|
template <const bool isServer, typename Impl>
|
|
struct WIN32_EXPORT WebSocketProtocol {
|
|
public:
|
|
static const unsigned int SHORT_MESSAGE_HEADER = isServer ? 6 : 2;
|
|
static const unsigned int MEDIUM_MESSAGE_HEADER = isServer ? 8 : 4;
|
|
static const unsigned int LONG_MESSAGE_HEADER = isServer ? 14 : 10;
|
|
|
|
protected:
|
|
static inline bool isFin(char *frame) {return *((unsigned char *) frame) & 128;}
|
|
static inline unsigned char getOpCode(char *frame) {return *((unsigned char *) frame) & 15;}
|
|
static inline unsigned char payloadLength(char *frame) {return ((unsigned char *) frame)[1] & 127;}
|
|
static inline bool rsv23(char *frame) {return *((unsigned char *) frame) & 48;}
|
|
static inline bool rsv1(char *frame) {return *((unsigned char *) frame) & 64;}
|
|
|
|
static inline void unmaskImprecise(char *dst, char *src, char *mask, unsigned int length) {
|
|
for (unsigned int n = (length >> 2) + 1; n; n--) {
|
|
*(dst++) = *(src++) ^ mask[0];
|
|
*(dst++) = *(src++) ^ mask[1];
|
|
*(dst++) = *(src++) ^ mask[2];
|
|
*(dst++) = *(src++) ^ mask[3];
|
|
}
|
|
}
|
|
|
|
static inline void unmaskImpreciseCopyMask(char *dst, char *src, char *maskPtr, unsigned int length) {
|
|
char mask[4] = {maskPtr[0], maskPtr[1], maskPtr[2], maskPtr[3]};
|
|
unmaskImprecise(dst, src, mask, length);
|
|
}
|
|
|
|
static inline void rotateMask(unsigned int offset, char *mask) {
|
|
char originalMask[4] = {mask[0], mask[1], mask[2], mask[3]};
|
|
mask[(0 + offset) % 4] = originalMask[0];
|
|
mask[(1 + offset) % 4] = originalMask[1];
|
|
mask[(2 + offset) % 4] = originalMask[2];
|
|
mask[(3 + offset) % 4] = originalMask[3];
|
|
}
|
|
|
|
static inline void unmaskInplace(char *data, char *stop, char *mask) {
|
|
while (data < stop) {
|
|
*(data++) ^= mask[0];
|
|
*(data++) ^= mask[1];
|
|
*(data++) ^= mask[2];
|
|
*(data++) ^= mask[3];
|
|
}
|
|
}
|
|
|
|
template <unsigned int MESSAGE_HEADER, typename T>
|
|
static inline bool consumeMessage(T payLength, char *&src, unsigned int &length, WebSocketState<isServer> *wState, void *user) {
|
|
if (getOpCode(src)) {
|
|
if (wState->state.opStack == 1 || (!wState->state.lastFin && getOpCode(src) < 2)) {
|
|
Impl::forceClose(wState, user);
|
|
return true;
|
|
}
|
|
wState->state.opCode[++wState->state.opStack] = (OpCode) getOpCode(src);
|
|
} else if (wState->state.opStack == -1) {
|
|
Impl::forceClose(wState, user);
|
|
return true;
|
|
}
|
|
wState->state.lastFin = isFin(src);
|
|
|
|
if (Impl::refusePayloadLength(payLength, wState, user)) {
|
|
Impl::forceClose(wState, user);
|
|
return true;
|
|
}
|
|
|
|
if (payLength + MESSAGE_HEADER <= length) {
|
|
if (isServer) {
|
|
unmaskImpreciseCopyMask(src + MESSAGE_HEADER - 4, src + MESSAGE_HEADER, src + MESSAGE_HEADER - 4, (unsigned int) payLength);
|
|
if (Impl::handleFragment(src + MESSAGE_HEADER - 4, payLength, 0, wState->state.opCode[wState->state.opStack], isFin(src), wState, user)) {
|
|
return true;
|
|
}
|
|
} else {
|
|
if (Impl::handleFragment(src + MESSAGE_HEADER, payLength, 0, wState->state.opCode[wState->state.opStack], isFin(src), wState, user)) {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
if (isFin(src)) {
|
|
wState->state.opStack--;
|
|
}
|
|
|
|
src += payLength + MESSAGE_HEADER;
|
|
length -= (unsigned int) (payLength + MESSAGE_HEADER);
|
|
wState->state.spillLength = 0;
|
|
return false;
|
|
} else {
|
|
wState->state.spillLength = 0;
|
|
wState->state.wantsHead = false;
|
|
wState->remainingBytes = (unsigned int) (payLength - length + MESSAGE_HEADER);
|
|
bool fin = isFin(src);
|
|
if (isServer) {
|
|
memcpy(wState->mask, src + MESSAGE_HEADER - 4, 4);
|
|
unmaskImprecise(src, src + MESSAGE_HEADER, wState->mask, length - MESSAGE_HEADER);
|
|
rotateMask(4 - (length - MESSAGE_HEADER) % 4, wState->mask);
|
|
} else {
|
|
src += MESSAGE_HEADER;
|
|
}
|
|
Impl::handleFragment(src, length - MESSAGE_HEADER, wState->remainingBytes, wState->state.opCode[wState->state.opStack], fin, wState, user);
|
|
return true;
|
|
}
|
|
}
|
|
|
|
static inline bool consumeContinuation(char *&src, unsigned int &length, WebSocketState<isServer> *wState, void *user) {
|
|
if (wState->remainingBytes <= length) {
|
|
if (isServer) {
|
|
int n = wState->remainingBytes >> 2;
|
|
unmaskInplace(src, src + n * 4, wState->mask);
|
|
for (int i = 0, s = wState->remainingBytes % 4; i < s; i++) {
|
|
src[n * 4 + i] ^= wState->mask[i];
|
|
}
|
|
}
|
|
|
|
if (Impl::handleFragment(src, wState->remainingBytes, 0, wState->state.opCode[wState->state.opStack], wState->state.lastFin, wState, user)) {
|
|
return false;
|
|
}
|
|
|
|
if (wState->state.lastFin) {
|
|
wState->state.opStack--;
|
|
}
|
|
|
|
src += wState->remainingBytes;
|
|
length -= wState->remainingBytes;
|
|
wState->state.wantsHead = true;
|
|
return true;
|
|
} else {
|
|
if (isServer) {
|
|
unmaskInplace(src, src + ((length >> 2) + 1) * 4, wState->mask);
|
|
}
|
|
|
|
wState->remainingBytes -= length;
|
|
if (Impl::handleFragment(src, length, wState->remainingBytes, wState->state.opCode[wState->state.opStack], wState->state.lastFin, wState, user)) {
|
|
return false;
|
|
}
|
|
|
|
if (isServer && length % 4) {
|
|
rotateMask(4 - (length % 4), wState->mask);
|
|
}
|
|
return false;
|
|
}
|
|
}
|
|
|
|
public:
|
|
WebSocketProtocol() {
|
|
|
|
}
|
|
|
|
static inline void consume(char *src, unsigned int length, WebSocketState<isServer> *wState, void *user) {
|
|
if (wState->state.spillLength) {
|
|
src -= wState->state.spillLength;
|
|
length += wState->state.spillLength;
|
|
memcpy(src, wState->state.spill, wState->state.spillLength);
|
|
}
|
|
if (wState->state.wantsHead) {
|
|
parseNext:
|
|
while (length >= SHORT_MESSAGE_HEADER) {
|
|
|
|
// invalid reserved bits / invalid opcodes / invalid control frames / set compressed frame
|
|
if ((rsv1(src) && !Impl::setCompressed(wState, user)) || rsv23(src) || (getOpCode(src) > 2 && getOpCode(src) < 8) ||
|
|
getOpCode(src) > 10 || (getOpCode(src) > 2 && (!isFin(src) || payloadLength(src) > 125))) {
|
|
Impl::forceClose(wState, user);
|
|
return;
|
|
}
|
|
|
|
if (payloadLength(src) < 126) {
|
|
if (consumeMessage<SHORT_MESSAGE_HEADER, uint8_t>(payloadLength(src), src, length, wState, user)) {
|
|
return;
|
|
}
|
|
} else if (payloadLength(src) == 126) {
|
|
if (length < MEDIUM_MESSAGE_HEADER) {
|
|
break;
|
|
} else if(consumeMessage<MEDIUM_MESSAGE_HEADER, uint16_t>(protocol::cond_byte_swap<uint16_t>(protocol::bit_cast<uint16_t>(src + 2)), src, length, wState, user)) {
|
|
return;
|
|
}
|
|
} else if (length < LONG_MESSAGE_HEADER) {
|
|
break;
|
|
} else if (consumeMessage<LONG_MESSAGE_HEADER, uint64_t>(protocol::cond_byte_swap<uint64_t>(protocol::bit_cast<uint64_t>(src + 2)), src, length, wState, user)) {
|
|
return;
|
|
}
|
|
}
|
|
if (length) {
|
|
memcpy(wState->state.spill, src, length);
|
|
wState->state.spillLength = length & 0xf;
|
|
}
|
|
} else if (consumeContinuation(src, length, wState, user)) {
|
|
goto parseNext;
|
|
}
|
|
}
|
|
|
|
static const int CONSUME_POST_PADDING = 4;
|
|
static const int CONSUME_PRE_PADDING = LONG_MESSAGE_HEADER - 1;
|
|
};
|
|
|
|
}
|
|
|
|
#endif // UWS_WEBSOCKETPROTOCOL_H
|