mirror of
https://github.com/espressif/esp-protocols.git
synced 2025-07-17 12:32:14 +02:00
CMUX: Refactor the protocol decoder to multiple methods per cmux state
This commit is contained in:
David Cermak
@ -55,33 +55,74 @@ class CMuxInstance;
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class CMux {
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public:
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explicit CMux(std::unique_ptr<Terminal> t, std::unique_ptr<uint8_t[]> b, size_t buff_size):
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term(std::move(t)), buffer_size(buff_size), buffer(std::move(b)), payload_start(nullptr), total_payload_size(0) {}
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term(std::move(t)), payload_start(nullptr), total_payload_size(0), buffer_size(buff_size), buffer(std::move(b)) {}
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~CMux() = default;
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/**
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* @brief Initializes CMux protocol
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* @return true on success
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*/
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[[nodiscard]] bool init();
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/**
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* @brief Sets read callback for the appropriate terminal
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* @param inst Index of the terminal
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* @param f function pointer
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*/
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void set_read_cb(int inst, std::function<bool(uint8_t *data, size_t len)> f);
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/**
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* @brief Writes to the appropriate terminal
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* @param i Index of the terminal
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* @param data Data to write
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* @param len Data length to write
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* @return The actual written length
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*/
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int write(int i, uint8_t *data, size_t len);
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private:
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std::function<bool(uint8_t *data, size_t len)> read_cb[max_terms];
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void data_available(uint8_t *data, size_t len);
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void send_sabm(size_t i);
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std::unique_ptr<Terminal> term;
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cmux_state state;
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static uint8_t fcs_crc(const uint8_t frame[6]); /*!< Utility to calculate FCS CRC */
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void data_available(uint8_t *data, size_t len); /*!< Called when valid data available */
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void send_sabm(size_t i); /*!< Sending initial SABM */
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bool on_cmux(uint8_t *data, size_t len); /*!< Called from terminal layer when raw CMUX protocol data available */
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struct CMuxFrame; /*!< Forward declare the Frame struct, used in protocol decoders */
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/**
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* These methods serve different states of the CMUX protocols
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* @param frame Currently available cmux frame (basically data, size, methods)
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* @return - true if the state processed successfully
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* - false if more data needed to process the current state
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*/
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bool on_recovery(CMuxFrame &frame);
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bool on_init(CMuxFrame &frame);
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bool on_header(CMuxFrame &frame);
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bool on_payload(CMuxFrame &frame);
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bool on_footer(CMuxFrame &frame);
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std::function<bool(uint8_t *data, size_t len)> read_cb[MAX_TERMINALS_NUM]; /*!< Function pointers to read callbacks */
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std::unique_ptr<Terminal> term; /*!< The original terminal */
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cmux_state state; /*!< CMux protocol state */
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/**
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* CMux control fields and offsets
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*/
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uint8_t dlci;
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uint8_t type;
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size_t payload_len;
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uint8_t frame_header[6];
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size_t frame_header_offset;
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size_t buffer_size;
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std::unique_ptr<uint8_t[]> buffer;
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bool on_cmux(uint8_t *data, size_t len);
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static uint8_t fcs_crc(const uint8_t frame[6]);
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Lock lock;
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int instance;
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int sabm_ack;
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uint8_t *payload_start;
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size_t total_payload_size;
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int instance;
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int sabm_ack;
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/**
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* Processing buffer size and pointer
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*/
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size_t buffer_size;
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std::unique_ptr<uint8_t[]> buffer;
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Lock lock;
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};
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/**
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@ -91,11 +91,21 @@ void CMux::send_sabm(size_t i)
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}
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struct CMux::CMuxFrame {
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uint8_t *ptr; /*!< pointer to the currently processing byte of the CMUX frame */
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size_t len; /*!< length of available data in the current CMUX frame */
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void advance(int size = 1)
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{
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ptr += size;
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len -= size;
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}
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};
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void CMux::data_available(uint8_t *data, size_t len)
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{
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if (data && type == 0xFF && len > 0 && dlci > 0) {
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int virtual_term = dlci - 1;
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if (virtual_term < max_terms && read_cb[virtual_term]) {
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if (virtual_term < MAX_TERMINALS_NUM && read_cb[virtual_term]) {
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// Post partial data (or defragment to post on CMUX footer)
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#ifdef DEFRAGMENT_CMUX_PAYLOAD
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if (payload_start == nullptr) {
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@ -112,15 +122,126 @@ void CMux::data_available(uint8_t *data, size_t len)
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sabm_ack = dlci;
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} else if (data == nullptr) {
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int virtual_term = dlci - 1;
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if (virtual_term < max_terms && read_cb[virtual_term]) {
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if (virtual_term < MAX_TERMINALS_NUM && read_cb[virtual_term]) {
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#ifdef DEFRAGMENT_CMUX_PAYLOAD
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read_cb[virtual_term](payload_start, total_payload_size);
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#endif
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}
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}
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}
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bool CMux::on_init(CMuxFrame &frame)
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{
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if (frame.ptr[0] != SOF_MARKER) {
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ESP_LOGW("CMUX", "Protocol mismatch: Missed leading SOF, recovering...");
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state = cmux_state::RECOVER;
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return true;
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}
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if (frame.len > 1 && frame.ptr[1] == SOF_MARKER) {
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// empty frame
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frame.advance();
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return true;
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}
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state = cmux_state::HEADER;
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frame.advance();
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frame_header_offset = 1;
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return true;
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}
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bool CMux::on_recovery(CMuxFrame &frame)
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{
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uint8_t *recover_ptr;
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if (frame.ptr[0] == SOF_MARKER) {
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// already init state
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state = cmux_state::INIT;
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return true;
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}
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recover_ptr = static_cast<uint8_t *>(memchr(frame.ptr, SOF_MARKER, frame.len));
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if (recover_ptr && frame.len > recover_ptr - frame.ptr) {
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frame.len -= (recover_ptr - frame.ptr);
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frame.ptr = recover_ptr;
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state = cmux_state::INIT;
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ESP_LOGI("CMUX", "Protocol recovered");
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if (frame.len > 1 && frame.ptr[1] == SOF_MARKER) {
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// empty frame
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frame.advance();
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}
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return true;
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}
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// marker not found, continue with recovery
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return false;
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}
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bool CMux::on_header(CMuxFrame &frame)
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{
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if (frame.len > 0 && frame_header_offset == 1 && frame.ptr[0] == SOF_MARKER) {
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// Previously trailing SOF interpreted as heading SOF, remove it and restart HEADER
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frame.advance();
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return true;
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}
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if (frame.len + frame_header_offset < 4) {
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memcpy(frame_header + frame_header_offset, frame.ptr, frame.len);
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frame_header_offset += frame.len;
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return false; // need read more
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}
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size_t payload_offset = std::min(frame.len, 4 - frame_header_offset);
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memcpy(frame_header + frame_header_offset, frame.ptr, payload_offset);
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frame_header_offset += payload_offset;
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dlci = frame_header[1] >> 2;
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type = frame_header[2];
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payload_len = (frame_header[3] >> 1);
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frame.advance(payload_offset);
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state = cmux_state::PAYLOAD;
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return true;
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}
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bool CMux::on_payload(CMuxFrame &frame)
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{
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ESP_LOGD("CMUX", "Payload frame: dlci:%02x type:%02x payload:%d available:%d", dlci, type, payload_len, frame.len);
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if (frame.len < payload_len) { // payload
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state = cmux_state::PAYLOAD;
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data_available(frame.ptr, frame.len); // partial read
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payload_len -= frame.len;
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return false;
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} else { // complete
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if (payload_len > 0) {
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data_available(&frame.ptr[0], payload_len); // rest read
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}
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frame.advance((payload_len));
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state = cmux_state::FOOTER;
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payload_len = 0;
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}
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return true;
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}
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bool CMux::on_footer(CMuxFrame &frame)
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{
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size_t footer_offset = 0;
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if (frame.len + frame_header_offset < 6) {
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memcpy(frame_header + frame_header_offset, frame.ptr, frame.len);
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frame_header_offset += frame.len;
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return false; // need read more
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} else {
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footer_offset = std::min(frame.len, 6 - frame_header_offset);
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memcpy(frame_header + frame_header_offset, frame.ptr, footer_offset);
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if (frame_header[5] != SOF_MARKER) {
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ESP_LOGW("CMUX", "Protocol mismatch: Missed trailing SOF, recovering...");
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payload_start = nullptr;
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total_payload_size = 0;
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state = cmux_state::RECOVER;
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return true;
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}
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frame.advance(footer_offset);
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state = cmux_state::INIT;
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frame_header_offset = 0;
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data_available(nullptr, 0);
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payload_start = nullptr;
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total_payload_size = 0;
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}
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return true;
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}
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bool CMux::on_cmux(uint8_t *data, size_t actual_len)
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{
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if (!data) {
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@ -138,113 +259,33 @@ bool CMux::on_cmux(uint8_t *data, size_t actual_len)
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actual_len = term->read(data, buffer_size);
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#endif
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}
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ESP_LOG_BUFFER_HEXDUMP("CMUX Received", data, actual_len, ESP_LOG_DEBUG);
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uint8_t *frame = data;
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uint8_t *recover_ptr;
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auto available_len = actual_len;
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size_t payload_offset = 0;
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size_t footer_offset = 0;
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while (available_len > 0) {
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ESP_LOG_BUFFER_HEXDUMP("CMUX Received", data, actual_len, ESP_LOG_VERBOSE);
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CMuxFrame frame = { .ptr = data, .len = actual_len };
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while (frame.len > 0) {
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switch (state) {
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case cmux_state::RECOVER:
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if (frame[0] == SOF_MARKER) {
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// already init state
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state = cmux_state::INIT;
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break;
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if (!on_recovery(frame)) {
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return false;
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}
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recover_ptr = static_cast<uint8_t *>(memchr(frame, SOF_MARKER, available_len));
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if (recover_ptr && available_len > recover_ptr - frame) {
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available_len -= (recover_ptr - frame);
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frame = recover_ptr;
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state = cmux_state::INIT;
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ESP_LOGI("CMUX", "Protocol recovered");
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if (available_len > 1 && frame[1] == SOF_MARKER) {
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// empty frame
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available_len -= 1;
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frame += 1;
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}
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break;
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}
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// marker not found, continue with recovery
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return false;
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break;
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case cmux_state::INIT:
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if (frame[0] != SOF_MARKER) {
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ESP_LOGW("CMUX", "Protocol mismatch: Missed leading SOF, recovering...");
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state = cmux_state::RECOVER;
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break;
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if (!on_init(frame)) {
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return false;
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}
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if (available_len > 1 && frame[1] == SOF_MARKER) {
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// empty frame
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available_len -= 1;
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frame += 1;
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break;
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}
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state = cmux_state::HEADER;
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available_len--;
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frame_header_offset = 1;
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frame++;
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break;
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case cmux_state::HEADER:
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if (available_len > 0 && frame_header_offset == 1 && frame[0] == SOF_MARKER) {
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// Previously trailing SOF interpreted as heading SOF, remove it and restart HEADER
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available_len--;
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frame++;
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break;
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if (!on_header(frame)) {
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return false;
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}
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if (available_len + frame_header_offset < 4) {
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memcpy(frame_header + frame_header_offset, frame, available_len);
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frame_header_offset += available_len;
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return false; // need read more
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}
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payload_offset = std::min(available_len, 4 - frame_header_offset);
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memcpy(frame_header + frame_header_offset, frame, payload_offset);
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frame_header_offset += payload_offset;
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dlci = frame_header[1] >> 2;
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type = frame_header[2];
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payload_len = (frame_header[3] >> 1);
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frame += payload_offset;
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available_len -= payload_offset;
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state = cmux_state::PAYLOAD;
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break;
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case cmux_state::PAYLOAD:
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ESP_LOGD("CMUX", "Payload frame: dlci:%02x type:%02x payload:%d available:%d", dlci, type, payload_len, available_len);
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if (available_len < payload_len) { // payload
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state = cmux_state::PAYLOAD;
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data_available(frame, available_len); // partial read
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payload_len -= available_len;
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if (!on_payload(frame)) {
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return false;
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} else { // complete
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if (payload_len > 0) {
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data_available(&frame[0], payload_len); // rest read
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}
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available_len -= payload_len;
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frame += payload_len;
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state = cmux_state::FOOTER;
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payload_len = 0;
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}
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break;
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case cmux_state::FOOTER:
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if (available_len + frame_header_offset < 6) {
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memcpy(frame_header + frame_header_offset, frame, available_len);
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frame_header_offset += available_len;
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return false; // need read more
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} else {
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footer_offset = std::min(available_len, 6 - frame_header_offset);
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memcpy(frame_header + frame_header_offset, frame, footer_offset);
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if (frame_header[5] != SOF_MARKER) {
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ESP_LOGW("CMUX", "Protocol mismatch: Missed trailing SOF, recovering...");
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payload_start = nullptr;
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total_payload_size = 0;
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state = cmux_state::RECOVER;
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break;
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}
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frame += footer_offset;
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available_len -= footer_offset;
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state = cmux_state::INIT;
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frame_header_offset = 0;
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data_available(nullptr, 0);
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payload_start = nullptr;
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total_payload_size = 0;
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if (!on_footer(frame)) {
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return false;
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}
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break;
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}
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@ -313,7 +354,7 @@ int CMux::write(int virtual_term, uint8_t *data, size_t len)
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void CMux::set_read_cb(int inst, std::function<bool(uint8_t *, size_t)> f)
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{
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if (inst < max_terms) {
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if (inst < MAX_TERMINALS_NUM) {
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read_cb[inst] = std::move(f);
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}
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}
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