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tannewttannewt
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Split listdir entries across two packets
when the MTU of the BLE connection is smaller than the 28 bytes of the header. (The smallest possible MTU is 20.) Fixes adafruit#5511
1 parent a8b69f2 commit bf0bef9

2 files changed

Lines changed: 26 additions & 8 deletions

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‎ports/nrf/common-hal/_bleio/PacketBuffer.c‎

Lines changed: 6 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -356,9 +356,12 @@ mp_int_t common_hal_bleio_packet_buffer_write(bleio_packet_buffer_obj_t *self, c
356356
if (self->conn_handle == BLE_CONN_HANDLE_INVALID) {
357357
return -1;
358358
}
359-
uint16_t outgoing_packet_length = common_hal_bleio_packet_buffer_get_outgoing_packet_length(self);
359+
mp_int_t outgoing_packet_length = common_hal_bleio_packet_buffer_get_outgoing_packet_length(self);
360+
if (outgoing_packet_length < 0) {
361+
return -1;
362+
}
360363

361-
uint16_t total_len = len + header_len;
364+
mp_int_t total_len = len + header_len;
362365
if (total_len > outgoing_packet_length) {
363366
// Supplied data will not fit in a single BLE packet.
364367
mp_raise_ValueError_varg(translate("Total data to write is larger than %q"), MP_QSTR_outgoing_packet_length);
@@ -369,7 +372,7 @@ mp_int_t common_hal_bleio_packet_buffer_write(bleio_packet_buffer_obj_t *self, c
369372
}
370373
outgoing_packet_length = MIN(outgoing_packet_length, self->max_packet_size);
371374

372-
if (len + self->pending_size > outgoing_packet_length) {
375+
if (len + self->pending_size > (size_t)outgoing_packet_length) {
373376
// No room to append len bytes to packet. Wait until we get a free buffer,
374377
// and keep checking that we haven't been disconnected.
375378
while (self->pending_size != 0 &&

‎supervisor/shared/bluetooth/file_transfer.c‎

Lines changed: 20 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -525,18 +525,33 @@ STATIC uint8_t _process_mkdir(const uint8_t *raw_buf, size_t command_len) {
525525
return ANY_COMMAND;
526526
}
527527

528+
STATIC void send_listdir_entry_header(const struct listdir_entry *entry, mp_int_t max_packet_size) {
529+
mp_int_t response_size = sizeof(struct listdir_entry);
530+
if (max_packet_size >= response_size) {
531+
common_hal_bleio_packet_buffer_write(&_transfer_packet_buffer, (const uint8_t *)entry, response_size, NULL, 0);
532+
return;
533+
}
534+
// Split into 16 + 12 size packets to fit into 20 byte minimum packet size.
535+
common_hal_bleio_packet_buffer_write(&_transfer_packet_buffer, (const uint8_t *)entry, 16, NULL, 0);
536+
common_hal_bleio_packet_buffer_write(&_transfer_packet_buffer, ((const uint8_t *)entry) + 16, response_size - 16, NULL, 0);
537+
}
538+
528539
STATIC uint8_t _process_listdir(uint8_t *raw_buf, size_t command_len) {
529540
const struct listdir_command *command = (struct listdir_command *)raw_buf;
530541
struct listdir_entry *entry = (struct listdir_entry *)raw_buf;
531542
size_t header_size = sizeof(struct listdir_command);
532-
size_t response_size = sizeof(struct listdir_entry);
543+
mp_int_t max_packet_size = common_hal_bleio_packet_buffer_get_outgoing_packet_length(&_transfer_packet_buffer);
544+
if (max_packet_size < 0) {
545+
// -1 means we're disconnected
546+
return ANY_COMMAND;
547+
}
533548
// We reuse the command buffer so that we can produce long packets without
534549
// making the stack large.
535550
if (command->path_length > (COMMAND_SIZE - header_size - 1)) { // -1 for the null we'll write
536551
// TODO: throw away any more packets of path.
537552
entry->command = LISTDIR_ENTRY;
538553
entry->status = STATUS_ERROR;
539-
common_hal_bleio_packet_buffer_write(&_transfer_packet_buffer, (const uint8_t *)entry, response_size, NULL, 0);
554+
send_listdir_entry_header(entry, max_packet_size);
540555
return ANY_COMMAND;
541556
}
542557
// We need to receive another packet to have the full path.
@@ -560,7 +575,7 @@ STATIC uint8_t _process_listdir(uint8_t *raw_buf, size_t command_len) {
560575

561576
if (res != FR_OK) {
562577
entry->status = STATUS_ERROR_NO_FILE;
563-
common_hal_bleio_packet_buffer_write(&_transfer_packet_buffer, (const uint8_t *)entry, response_size, NULL, 0);
578+
send_listdir_entry_header(entry, max_packet_size);
564579
return ANY_COMMAND;
565580
}
566581
FILINFO file_info;
@@ -594,7 +609,7 @@ STATIC uint8_t _process_listdir(uint8_t *raw_buf, size_t command_len) {
594609

595610
size_t name_length = strlen(file_info.fname);
596611
entry->path_length = name_length;
597-
common_hal_bleio_packet_buffer_write(&_transfer_packet_buffer, (const uint8_t *)entry, response_size, NULL, 0);
612+
send_listdir_entry_header(entry, max_packet_size);
598613
size_t fn_offset = 0;
599614
while (fn_offset < name_length) {
600615
size_t fn_size = MIN(name_length - fn_offset, 4);
@@ -607,7 +622,7 @@ STATIC uint8_t _process_listdir(uint8_t *raw_buf, size_t command_len) {
607622
entry->entry_number = entry->entry_count;
608623
entry->flags = 0;
609624
entry->file_size = 0;
610-
common_hal_bleio_packet_buffer_write(&_transfer_packet_buffer, (const uint8_t *)entry, response_size, NULL, 0);
625+
send_listdir_entry_header(entry, max_packet_size);
611626
return ANY_COMMAND;
612627
}
613628

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