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More changes for Austrian meters, untested

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This commit is contained in:
Gunnar Skjold
2021-12-06 10:47:08 +01:00
parent 178f603937
commit 2107ca50e4
2 changed files with 114 additions and 38 deletions
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47
src/ams/hdlc.cpp
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@@ -16,18 +16,21 @@ void mbus_hexdump(const uint8_t* buf, int len) {
}
int HDLC_validate(const uint8_t* d, int length, HDLCConfig* config, CosemDateTime* timestamp) {
HDLCHeader* h = (HDLCHeader*) d;
// Length field (11 lsb of format)
int len = (ntohs(h->format) & 0x7FF) + 2;
if(len > length)
if(length < 10)
return HDLC_FRAME_INCOMPLETE;
int len;
int headersize = 3;
int footersize = 1;
HDLCHeader* h = (HDLCHeader*) d;
uint8_t* ptr = (uint8_t*) &h[1];
// Frame format type 3
if((h->format & 0xF0) == 0xA0) {
// Length field (11 lsb of format)
len = (ntohs(h->format) & 0x7FF) + 2;
if(len > length)
return HDLC_FRAME_INCOMPLETE;
HDLCFooter* f = (HDLCFooter*) (d + len - sizeof *f);
footersize = sizeof *f;
@@ -64,16 +67,11 @@ int HDLC_validate(const uint8_t* d, int length, HDLCConfig* config, CosemDateTim
ptr += sizeof *t3;
} else if((h->format & 0xF0) == 0x00) {
MbusFooter* f = (MbusFooter*) (d + len - sizeof *f);
footersize = sizeof *f;
// First and last byte should be MBUS_HAN_TAG
if(h->flag != MBUS_START || f->flag != MBUS_END)
// First byte should be start byte
if(h->flag != MBUS_START)
return HDLC_BOUNDRY_FLAG_MISSING;
// TODO: Verify FCS with crc8, not 16
//if(ntohs(f->fcs) != crc16_x25(d + 1, len - sizeof *f - 1))
// return HDLC_FCS_ERROR;
// TODO: Check that the two next bytes are identical
// Ignore: Flag + Control field + Address
ptr += 3;
@@ -112,6 +110,11 @@ int HDLC_validate(const uint8_t* d, int length, HDLCConfig* config, CosemDateTim
return ptr-d;
} else if(((*ptr) & 0xFF) == 0xDB) {
if(length < headersize + 18)
return HDLC_FRAME_INCOMPLETE;
uint8_t preheadersize = headersize;
ptr++;
// Encrypted APDU
// http://www.weigu.lu/tutorials/sensors2bus/04_encryption/index.html
@@ -127,15 +130,23 @@ int HDLC_validate(const uint8_t* d, int length, HDLCConfig* config, CosemDateTim
ptr += systemTitleLength;
if(((*ptr) & 0xFF) == 0x81) {
ptr++;
len = *ptr;
// 1-byte payload length
ptr++;
} else if(((*ptr) & 0xFF) == 0x82) {
ptr++;
headersize++;
// 2-byte payload length
ptr += 2;
headersize += 2;
HDLCHeader* h = (HDLCHeader*) d;
// Length field (11 lsb of format)
len = (ntohs(h->format) & 0xFFFF);
ptr += 3;
headersize += 3;
}
len += preheadersize;
if(len > length)
return HDLC_FRAME_INCOMPLETE;
// TODO: FCS
memcpy(config->additional_authenticated_data, ptr, 1);