378 lines
13 KiB
C++
378 lines
13 KiB
C++
#ifndef WEBSOCKETPROTOCOL_UWS_H
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#define WEBSOCKETPROTOCOL_UWS_H
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// we do need to include this for htobe64, should be moved from networking!
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#include "Networking.h"
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#include <cstring>
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#include <cstdlib>
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namespace uWS {
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enum OpCode : unsigned char {
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TEXT = 1,
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BINARY = 2,
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CLOSE = 8,
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PING = 9,
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PONG = 10
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};
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enum {
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CLIENT,
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SERVER
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};
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// 24 bytes perfectly
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template <bool isServer>
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struct WebSocketState {
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public:
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static const unsigned int SHORT_MESSAGE_HEADER = isServer ? 6 : 2;
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static const unsigned int MEDIUM_MESSAGE_HEADER = isServer ? 8 : 4;
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static const unsigned int LONG_MESSAGE_HEADER = isServer ? 14 : 10;
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// 16 bytes
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struct State {
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unsigned int wantsHead : 1;
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unsigned int spillLength : 4;
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int opStack : 2; // -1, 0, 1
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unsigned int lastFin : 1;
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// 15 bytes
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unsigned char spill[LONG_MESSAGE_HEADER - 1];
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OpCode opCode[2];
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State() {
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wantsHead = true;
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spillLength = 0;
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opStack = -1;
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lastFin = true;
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}
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} state;
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// 8 bytes
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unsigned int remainingBytes = 0;
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char mask[isServer ? 4 : 1];
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};
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template <const bool isServer, class Impl>
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class WIN32_EXPORT WebSocketProtocol {
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public:
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static const unsigned int SHORT_MESSAGE_HEADER = isServer ? 6 : 2;
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static const unsigned int MEDIUM_MESSAGE_HEADER = isServer ? 8 : 4;
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static const unsigned int LONG_MESSAGE_HEADER = isServer ? 14 : 10;
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private:
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static inline bool isFin(char *frame) {return *((unsigned char *) frame) & 128;}
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static inline unsigned char getOpCode(char *frame) {return *((unsigned char *) frame) & 15;}
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static inline unsigned char payloadLength(char *frame) {return ((unsigned char *) frame)[1] & 127;}
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static inline bool rsv23(char *frame) {return *((unsigned char *) frame) & 48;}
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static inline bool rsv1(char *frame) {return *((unsigned char *) frame) & 64;}
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static inline void unmaskImprecise(char *dst, char *src, char *mask, unsigned int length) {
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for (unsigned int n = (length >> 2) + 1; n; n--) {
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*(dst++) = *(src++) ^ mask[0];
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*(dst++) = *(src++) ^ mask[1];
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*(dst++) = *(src++) ^ mask[2];
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*(dst++) = *(src++) ^ mask[3];
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}
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}
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static inline void unmaskImpreciseCopyMask(char *dst, char *src, char *maskPtr, unsigned int length) {
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char mask[4] = {maskPtr[0], maskPtr[1], maskPtr[2], maskPtr[3]};
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unmaskImprecise(dst, src, mask, length);
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}
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static inline void rotateMask(unsigned int offset, char *mask) {
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char originalMask[4] = {mask[0], mask[1], mask[2], mask[3]};
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mask[(0 + offset) % 4] = originalMask[0];
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mask[(1 + offset) % 4] = originalMask[1];
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mask[(2 + offset) % 4] = originalMask[2];
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mask[(3 + offset) % 4] = originalMask[3];
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}
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static inline void unmaskInplace(char *data, char *stop, char *mask) {
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while (data < stop) {
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*(data++) ^= mask[0];
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*(data++) ^= mask[1];
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*(data++) ^= mask[2];
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*(data++) ^= mask[3];
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}
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}
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enum {
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SND_CONTINUATION = 1,
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SND_NO_FIN = 2,
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SND_COMPRESSED = 64
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};
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template <unsigned int MESSAGE_HEADER, typename T>
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static inline bool consumeMessage(T payLength, char *&src, unsigned int &length, WebSocketState<isServer> *wState) {
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if (getOpCode(src)) {
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if (wState->state.opStack == 1 || (!wState->state.lastFin && getOpCode(src) < 2)) {
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Impl::forceClose(wState);
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return true;
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}
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wState->state.opCode[++wState->state.opStack] = (OpCode) getOpCode(src);
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} else if (wState->state.opStack == -1) {
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Impl::forceClose(wState);
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return true;
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}
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wState->state.lastFin = isFin(src);
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if (Impl::refusePayloadLength(payLength, wState)) {
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Impl::forceClose(wState);
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return true;
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}
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if (payLength + MESSAGE_HEADER <= length) {
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if (isServer) {
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unmaskImpreciseCopyMask(src + MESSAGE_HEADER - 4, src + MESSAGE_HEADER, src + MESSAGE_HEADER - 4, payLength);
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if (Impl::handleFragment(src + MESSAGE_HEADER - 4, payLength, 0, wState->state.opCode[wState->state.opStack], isFin(src), wState)) {
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return true;
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}
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} else {
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if (Impl::handleFragment(src + MESSAGE_HEADER, payLength, 0, wState->state.opCode[wState->state.opStack], isFin(src), wState)) {
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return true;
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}
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}
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if (isFin(src)) {
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wState->state.opStack--;
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}
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src += payLength + MESSAGE_HEADER;
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length -= payLength + MESSAGE_HEADER;
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wState->state.spillLength = 0;
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return false;
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} else {
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wState->state.spillLength = 0;
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wState->state.wantsHead = false;
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wState->remainingBytes = payLength - length + MESSAGE_HEADER;
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bool fin = isFin(src);
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if (isServer) {
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memcpy(wState->mask, src + MESSAGE_HEADER - 4, 4);
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unmaskImprecise(src, src + MESSAGE_HEADER, wState->mask, length - MESSAGE_HEADER);
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rotateMask(4 - (length - MESSAGE_HEADER) % 4, wState->mask);
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} else {
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src += MESSAGE_HEADER;
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}
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Impl::handleFragment(src, length - MESSAGE_HEADER, wState->remainingBytes, wState->state.opCode[wState->state.opStack], fin, wState);
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return true;
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}
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}
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static inline bool consumeContinuation(char *&src, unsigned int &length, WebSocketState<isServer> *wState) {
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if (wState->remainingBytes <= length) {
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if (isServer) {
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int n = wState->remainingBytes >> 2;
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unmaskInplace(src, src + n * 4, wState->mask);
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for (int i = 0, s = wState->remainingBytes % 4; i < s; i++) {
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src[n * 4 + i] ^= wState->mask[i];
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}
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}
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if (Impl::handleFragment(src, wState->remainingBytes, 0, wState->state.opCode[wState->state.opStack], wState->state.lastFin, wState)) {
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return false;
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}
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if (wState->state.lastFin) {
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wState->state.opStack--;
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}
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src += wState->remainingBytes;
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length -= wState->remainingBytes;
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wState->state.wantsHead = true;
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return true;
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} else {
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if (isServer) {
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unmaskInplace(src, src + ((length >> 2) + 1) * 4, wState->mask);
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}
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wState->remainingBytes -= length;
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if (Impl::handleFragment(src, length, wState->remainingBytes, wState->state.opCode[wState->state.opStack], wState->state.lastFin, wState)) {
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return false;
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}
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if (isServer && length % 4) {
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rotateMask(4 - (length % 4), wState->mask);
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}
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return false;
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}
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}
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public:
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WebSocketProtocol() {
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}
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// Based on utf8_check.c by Markus Kuhn, 2005
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// https://www.cl.cam.ac.uk/~mgk25/ucs/utf8_check.c
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// Optimized for predominantly 7-bit content by Alex Hultman, 2016
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// Licensed as Zlib, like the rest of this project
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static bool isValidUtf8(unsigned char *s, size_t length)
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{
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for (unsigned char *e = s + length; s != e; ) {
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if (s + 4 <= e && ((*(uint32_t *) s) & 0x80808080) == 0) {
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s += 4;
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} else {
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while (!(*s & 0x80)) {
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if (++s == e) {
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return true;
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}
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}
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if ((s[0] & 0x60) == 0x40) {
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if (s + 1 >= e || (s[1] & 0xc0) != 0x80 || (s[0] & 0xfe) == 0xc0) {
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return false;
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}
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s += 2;
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} else if ((s[0] & 0xf0) == 0xe0) {
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if (s + 2 >= e || (s[1] & 0xc0) != 0x80 || (s[2] & 0xc0) != 0x80 ||
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(s[0] == 0xe0 && (s[1] & 0xe0) == 0x80) || (s[0] == 0xed && (s[1] & 0xe0) == 0xa0)) {
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return false;
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}
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s += 3;
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} else if ((s[0] & 0xf8) == 0xf0) {
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if (s + 3 >= e || (s[1] & 0xc0) != 0x80 || (s[2] & 0xc0) != 0x80 || (s[3] & 0xc0) != 0x80 ||
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(s[0] == 0xf0 && (s[1] & 0xf0) == 0x80) || (s[0] == 0xf4 && s[1] > 0x8f) || s[0] > 0xf4) {
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return false;
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}
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s += 4;
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} else {
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return false;
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}
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}
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}
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return true;
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}
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struct CloseFrame {
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uint16_t code;
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char *message;
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size_t length;
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};
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static inline CloseFrame parseClosePayload(char *src, size_t length) {
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CloseFrame cf = {};
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if (length >= 2) {
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memcpy(&cf.code, src, 2);
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cf = {ntohs(cf.code), src + 2, length - 2};
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if (cf.code < 1000 || cf.code > 4999 || (cf.code > 1011 && cf.code < 4000) ||
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(cf.code >= 1004 && cf.code <= 1006) || !isValidUtf8((unsigned char *) cf.message, cf.length)) {
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return {};
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}
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}
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return cf;
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}
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static inline size_t formatClosePayload(char *dst, uint16_t code, const char *message, size_t length) {
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if (code) {
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code = htons(code);
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memcpy(dst, &code, 2);
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memcpy(dst + 2, message, length);
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return length + 2;
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}
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return 0;
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}
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static inline size_t formatMessage(char *dst, const char *src, size_t length, OpCode opCode, size_t reportedLength, bool compressed) {
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size_t messageLength;
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size_t headerLength;
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if (reportedLength < 126) {
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headerLength = 2;
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dst[1] = reportedLength;
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} else if (reportedLength <= UINT16_MAX) {
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headerLength = 4;
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dst[1] = 126;
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*((uint16_t *) &dst[2]) = htons(reportedLength);
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} else {
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headerLength = 10;
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dst[1] = 127;
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*((uint64_t *) &dst[2]) = htobe64(reportedLength);
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}
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int flags = 0;
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dst[0] = (flags & SND_NO_FIN ? 0 : 128) | (compressed ? SND_COMPRESSED : 0);
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if (!(flags & SND_CONTINUATION)) {
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dst[0] |= opCode;
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}
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char mask[4];
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if (!isServer) {
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dst[1] |= 0x80;
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uint32_t random = rand();
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memcpy(mask, &random, 4);
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memcpy(dst + headerLength, &random, 4);
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headerLength += 4;
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}
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messageLength = headerLength + length;
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memcpy(dst + headerLength, src, length);
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if (!isServer) {
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// overwrites up to 3 bytes outside of the given buffer!
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//WebSocketProtocol<isServer>::unmaskInplace(dst + headerLength, dst + headerLength + length, mask);
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// this is not optimal
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char *start = dst + headerLength;
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char *stop = start + length;
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int i = 0;
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while (start != stop) {
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(*start++) ^= mask[i++ % 4];
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}
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}
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return messageLength;
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}
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static inline void consume(char *src, unsigned int length, WebSocketState<isServer> *wState) {
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if (wState->state.spillLength) {
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src -= wState->state.spillLength;
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length += wState->state.spillLength;
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memcpy(src, wState->state.spill, wState->state.spillLength);
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}
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if (wState->state.wantsHead) {
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parseNext:
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while (length >= SHORT_MESSAGE_HEADER) {
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// invalid reserved bits / invalid opcodes / invalid control frames / set compressed frame
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if ((rsv1(src) && !Impl::setCompressed(wState)) || rsv23(src) || (getOpCode(src) > 2 && getOpCode(src) < 8) ||
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getOpCode(src) > 10 || (getOpCode(src) > 2 && (!isFin(src) || payloadLength(src) > 125))) {
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Impl::forceClose(wState);
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return;
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}
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if (payloadLength(src) < 126) {
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if (consumeMessage<SHORT_MESSAGE_HEADER, uint8_t>(payloadLength(src), src, length, wState)) {
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return;
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}
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} else if (payloadLength(src) == 126) {
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if (length < MEDIUM_MESSAGE_HEADER) {
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break;
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} else if(consumeMessage<MEDIUM_MESSAGE_HEADER, uint16_t>(ntohs(*(uint16_t *) &src[2]), src, length, wState)) {
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return;
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}
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} else if (length < LONG_MESSAGE_HEADER) {
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break;
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} else if (consumeMessage<LONG_MESSAGE_HEADER, uint64_t>(be64toh(*(uint64_t *) &src[2]), src, length, wState)) {
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return;
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}
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}
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if (length) {
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memcpy(wState->state.spill, src, length);
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wState->state.spillLength = length;
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}
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} else if (consumeContinuation(src, length, wState)) {
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goto parseNext;
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}
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}
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static const int CONSUME_POST_PADDING = 4;
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static const int CONSUME_PRE_PADDING = LONG_MESSAGE_HEADER - 1;
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};
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}
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#endif // WEBSOCKETPROTOCOL_UWS_H
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