CMUX: Refactor the protocol decoder to multiple methods per cmux state

This commit is contained in:
David Cermak
2021-06-17 16:22:31 +02:00
parent 6e34954677
commit fb6029b66c
2 changed files with 192 additions and 110 deletions

View File

@ -91,11 +91,21 @@ void CMux::send_sabm(size_t i)
}
struct CMux::CMuxFrame {
uint8_t *ptr; /*!< pointer to the currently processing byte of the CMUX frame */
size_t len; /*!< length of available data in the current CMUX frame */
void advance(int size = 1)
{
ptr += size;
len -= size;
}
};
void CMux::data_available(uint8_t *data, size_t len)
{
if (data && type == 0xFF && len > 0 && dlci > 0) {
int virtual_term = dlci - 1;
if (virtual_term < max_terms && read_cb[virtual_term]) {
if (virtual_term < MAX_TERMINALS_NUM && read_cb[virtual_term]) {
// Post partial data (or defragment to post on CMUX footer)
#ifdef DEFRAGMENT_CMUX_PAYLOAD
if (payload_start == nullptr) {
@ -112,15 +122,126 @@ void CMux::data_available(uint8_t *data, size_t len)
sabm_ack = dlci;
} else if (data == nullptr) {
int virtual_term = dlci - 1;
if (virtual_term < max_terms && read_cb[virtual_term]) {
if (virtual_term < MAX_TERMINALS_NUM && read_cb[virtual_term]) {
#ifdef DEFRAGMENT_CMUX_PAYLOAD
read_cb[virtual_term](payload_start, total_payload_size);
#endif
}
}
}
bool CMux::on_init(CMuxFrame &frame)
{
if (frame.ptr[0] != SOF_MARKER) {
ESP_LOGW("CMUX", "Protocol mismatch: Missed leading SOF, recovering...");
state = cmux_state::RECOVER;
return true;
}
if (frame.len > 1 && frame.ptr[1] == SOF_MARKER) {
// empty frame
frame.advance();
return true;
}
state = cmux_state::HEADER;
frame.advance();
frame_header_offset = 1;
return true;
}
bool CMux::on_recovery(CMuxFrame &frame)
{
uint8_t *recover_ptr;
if (frame.ptr[0] == SOF_MARKER) {
// already init state
state = cmux_state::INIT;
return true;
}
recover_ptr = static_cast<uint8_t *>(memchr(frame.ptr, SOF_MARKER, frame.len));
if (recover_ptr && frame.len > recover_ptr - frame.ptr) {
frame.len -= (recover_ptr - frame.ptr);
frame.ptr = recover_ptr;
state = cmux_state::INIT;
ESP_LOGI("CMUX", "Protocol recovered");
if (frame.len > 1 && frame.ptr[1] == SOF_MARKER) {
// empty frame
frame.advance();
}
return true;
}
// marker not found, continue with recovery
return false;
}
bool CMux::on_header(CMuxFrame &frame)
{
if (frame.len > 0 && frame_header_offset == 1 && frame.ptr[0] == SOF_MARKER) {
// Previously trailing SOF interpreted as heading SOF, remove it and restart HEADER
frame.advance();
return true;
}
if (frame.len + frame_header_offset < 4) {
memcpy(frame_header + frame_header_offset, frame.ptr, frame.len);
frame_header_offset += frame.len;
return false; // need read more
}
size_t payload_offset = std::min(frame.len, 4 - frame_header_offset);
memcpy(frame_header + frame_header_offset, frame.ptr, payload_offset);
frame_header_offset += payload_offset;
dlci = frame_header[1] >> 2;
type = frame_header[2];
payload_len = (frame_header[3] >> 1);
frame.advance(payload_offset);
state = cmux_state::PAYLOAD;
return true;
}
bool CMux::on_payload(CMuxFrame &frame)
{
ESP_LOGD("CMUX", "Payload frame: dlci:%02x type:%02x payload:%d available:%d", dlci, type, payload_len, frame.len);
if (frame.len < payload_len) { // payload
state = cmux_state::PAYLOAD;
data_available(frame.ptr, frame.len); // partial read
payload_len -= frame.len;
return false;
} else { // complete
if (payload_len > 0) {
data_available(&frame.ptr[0], payload_len); // rest read
}
frame.advance((payload_len));
state = cmux_state::FOOTER;
payload_len = 0;
}
return true;
}
bool CMux::on_footer(CMuxFrame &frame)
{
size_t footer_offset = 0;
if (frame.len + frame_header_offset < 6) {
memcpy(frame_header + frame_header_offset, frame.ptr, frame.len);
frame_header_offset += frame.len;
return false; // need read more
} else {
footer_offset = std::min(frame.len, 6 - frame_header_offset);
memcpy(frame_header + frame_header_offset, frame.ptr, footer_offset);
if (frame_header[5] != SOF_MARKER) {
ESP_LOGW("CMUX", "Protocol mismatch: Missed trailing SOF, recovering...");
payload_start = nullptr;
total_payload_size = 0;
state = cmux_state::RECOVER;
return true;
}
frame.advance(footer_offset);
state = cmux_state::INIT;
frame_header_offset = 0;
data_available(nullptr, 0);
payload_start = nullptr;
total_payload_size = 0;
}
return true;
}
bool CMux::on_cmux(uint8_t *data, size_t actual_len)
{
if (!data) {
@ -138,113 +259,33 @@ bool CMux::on_cmux(uint8_t *data, size_t actual_len)
actual_len = term->read(data, buffer_size);
#endif
}
ESP_LOG_BUFFER_HEXDUMP("CMUX Received", data, actual_len, ESP_LOG_DEBUG);
uint8_t *frame = data;
uint8_t *recover_ptr;
auto available_len = actual_len;
size_t payload_offset = 0;
size_t footer_offset = 0;
while (available_len > 0) {
ESP_LOG_BUFFER_HEXDUMP("CMUX Received", data, actual_len, ESP_LOG_VERBOSE);
CMuxFrame frame = { .ptr = data, .len = actual_len };
while (frame.len > 0) {
switch (state) {
case cmux_state::RECOVER:
if (frame[0] == SOF_MARKER) {
// already init state
state = cmux_state::INIT;
break;
if (!on_recovery(frame)) {
return false;
}
recover_ptr = static_cast<uint8_t *>(memchr(frame, SOF_MARKER, available_len));
if (recover_ptr && available_len > recover_ptr - frame) {
available_len -= (recover_ptr - frame);
frame = recover_ptr;
state = cmux_state::INIT;
ESP_LOGI("CMUX", "Protocol recovered");
if (available_len > 1 && frame[1] == SOF_MARKER) {
// empty frame
available_len -= 1;
frame += 1;
}
break;
}
// marker not found, continue with recovery
return false;
break;
case cmux_state::INIT:
if (frame[0] != SOF_MARKER) {
ESP_LOGW("CMUX", "Protocol mismatch: Missed leading SOF, recovering...");
state = cmux_state::RECOVER;
break;
if (!on_init(frame)) {
return false;
}
if (available_len > 1 && frame[1] == SOF_MARKER) {
// empty frame
available_len -= 1;
frame += 1;
break;
}
state = cmux_state::HEADER;
available_len--;
frame_header_offset = 1;
frame++;
break;
case cmux_state::HEADER:
if (available_len > 0 && frame_header_offset == 1 && frame[0] == SOF_MARKER) {
// Previously trailing SOF interpreted as heading SOF, remove it and restart HEADER
available_len--;
frame++;
break;
if (!on_header(frame)) {
return false;
}
if (available_len + frame_header_offset < 4) {
memcpy(frame_header + frame_header_offset, frame, available_len);
frame_header_offset += available_len;
return false; // need read more
}
payload_offset = std::min(available_len, 4 - frame_header_offset);
memcpy(frame_header + frame_header_offset, frame, payload_offset);
frame_header_offset += payload_offset;
dlci = frame_header[1] >> 2;
type = frame_header[2];
payload_len = (frame_header[3] >> 1);
frame += payload_offset;
available_len -= payload_offset;
state = cmux_state::PAYLOAD;
break;
case cmux_state::PAYLOAD:
ESP_LOGD("CMUX", "Payload frame: dlci:%02x type:%02x payload:%d available:%d", dlci, type, payload_len, available_len);
if (available_len < payload_len) { // payload
state = cmux_state::PAYLOAD;
data_available(frame, available_len); // partial read
payload_len -= available_len;
if (!on_payload(frame)) {
return false;
} else { // complete
if (payload_len > 0) {
data_available(&frame[0], payload_len); // rest read
}
available_len -= payload_len;
frame += payload_len;
state = cmux_state::FOOTER;
payload_len = 0;
}
break;
case cmux_state::FOOTER:
if (available_len + frame_header_offset < 6) {
memcpy(frame_header + frame_header_offset, frame, available_len);
frame_header_offset += available_len;
return false; // need read more
} else {
footer_offset = std::min(available_len, 6 - frame_header_offset);
memcpy(frame_header + frame_header_offset, frame, footer_offset);
if (frame_header[5] != SOF_MARKER) {
ESP_LOGW("CMUX", "Protocol mismatch: Missed trailing SOF, recovering...");
payload_start = nullptr;
total_payload_size = 0;
state = cmux_state::RECOVER;
break;
}
frame += footer_offset;
available_len -= footer_offset;
state = cmux_state::INIT;
frame_header_offset = 0;
data_available(nullptr, 0);
payload_start = nullptr;
total_payload_size = 0;
if (!on_footer(frame)) {
return false;
}
break;
}
@ -313,7 +354,7 @@ int CMux::write(int virtual_term, uint8_t *data, size_t len)
void CMux::set_read_cb(int inst, std::function<bool(uint8_t *, size_t)> f)
{
if (inst < max_terms) {
if (inst < MAX_TERMINALS_NUM) {
read_cb[inst] = std::move(f);
}
}