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improve USB protocol decoding

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This commit is contained in:
Jan Käberich 2022-10-28 00:14:24 +02:00
parent 87429c076f
commit 658e8252b1
2 changed files with 28 additions and 9 deletions
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19
Software/VNA_embedded/Application/Communication/Protocol.cpp
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@ -52,22 +52,23 @@ uint16_t Protocol::DecodeBuffer(uint8_t *buf, uint16_t len, PacketInfo *info) {
}
/* Evaluate frame size */
uint16_t length = *(uint16_t*) &data[1];
if(len < length) {
uint16_t length = data[1] | ((uint16_t) data[2] << 8);
if(length > sizeof(PacketInfo) * 2 || length < 8) {
// larger than twice the maximum expected packet size or too small, probably an error, ignore
info->type = PacketType::None;
return 1;
}
if(len < length) {
/* The frame payload has not been completely received */
info->type = PacketType::None;
return data - buf;
}
if(length > sizeof(PacketInfo) * 2) {
// larger than twice the maximum expected packet size, probably an error, ignore
info->type = PacketType::None;
return 1;
}
/* The complete frame has been received, check checksum */
auto type = (PacketType) data[3];
uint32_t crc = *(uint32_t*) &data[length - 4];
uint32_t crc = (uint32_t) data[length-4] | ((uint32_t) data[length-3] << 8) | ((uint32_t) data[length-2] << 16) | ((uint32_t) data[length-1] << 24);
if(type != PacketType::VNADatapoint) {
uint32_t compare = CRC32(0, data, length - 4);
if(crc != compare) {