Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

[WIP] Class B fixes #481

Open
wants to merge 3 commits into
base: master
Choose a base branch
from
Open

[WIP] Class B fixes #481

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
2226826
Fix mac cmd size retrieval
sualko Oct 21, 2019
9ed48ca
Set class B flag if pingable
sualko Oct 21, 2019
b7bee3f
Fix beacon frequence in europe
sualko Oct 22, 2019
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 4 additions & 1 deletion src/lmic/lmic.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -711,7 +711,7 @@ static CONST_TABLE(u1_t, macCmdSize)[] = {
static u1_t getMacCmdSize(u1_t macCmd) {
if (macCmd < 2)
return 0;
if (macCmd >= LENOF_TABLE(macCmdSize) - 2)
if ((macCmd - 2) >= LENOF_TABLE(macCmdSize))
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Ugh. Sorry about this one.

Copy link
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

No problem, but I'm wondering why 0 is returned in the error case, because in scan_mac_cmds I see no check except for line 887, which doesn't do what the comment says.

https://github.com/sualko/arduino-lmic/blob/cabf6fbcd4390fcc42102a47c0323b7dafc6723a/src/lmic/lmic.c#L887

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yes, that's a bug too -- no test cases for bad mac commands, even in certification.

Should be if (cmdlen == 0 || cmdlen >> olen - oidx).

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This was fixed in 06b53c7, merged in #555 (and possibly before that, but that's the most recent change).

return 0;
return TABLE_GET_U1(macCmdSize, macCmd - 2);
}
Expand Down Expand Up @@ -1889,6 +1889,9 @@ static bit_t buildDataFrame (void) {
LMIC.frame[OFF_DAT_HDR] = HDR_FTYPE_DAUP | HDR_MAJOR_V1;
LMIC.frame[OFF_DAT_FCT] = (LMIC.dnConf | LMIC.adrEnabled
| (sendAdrAckReq() ? FCT_ADRACKReq : 0)
#if !defined(DISABLE_PING)
| ((LMIC.opmode & OP_PINGABLE) ? FCT_CLASSB : 0)
Copy link
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@terrillmoore I think LMIC.opmode & OP_PINGABLE is the wrong check, because this is true after LMIC_setPingable is called, but this doesn't mean that the periodic read has started (e.g. the device has no beacon received yet). Is OP_TRACK the right mask?

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I guess. The spec is not clear about this at all. Here's the relevant text (starting at line 1147, page 43, spec 1.0.3

The end-device application requests the LoRaWAN layer 1147 to switch to Class B mode. The LoRaWAN layer in the end-device searches for a beacon and returns either a BEACON_LOCKED service primitive to the application if a network beacon was found and locked or a BEACON_NOT_FOUND service primitive. To accelerate the beacon discovery the LoRaWAN layer MAY use the “DeviceTimeReq” MAC command.

Once in Class B mode, the MAC layer sets to 1 the Class B bit of the FCTRL field of every uplink frame transmitted.

From context, it does appear possible that they mean the device has to be locked to the beacon. So I think it makes sense to change to OP_TRACK, as that bit is set exactly when EV_BEACON_FOUND is reported.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Fixing as part of #208 major update.

#endif // ndef DISABLE_PING
| (end-OFF_DAT_OPTS));
os_wlsbf4(LMIC.frame+OFF_DAT_ADDR, LMIC.devaddr);

Expand Down
2 changes: 1 addition & 1 deletion src/lmic/lmic_eu868.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -236,7 +236,7 @@ ostime_t LMICeu868_nextTx(ostime_t now) {
#if !defined(DISABLE_BEACONS)
void LMICeu868_setBcnRxParams(void) {
LMIC.dataLen = 0;
LMIC.freq = LMIC.channelFreq[LMIC.bcnChnl] & ~(u4_t)3;
LMIC.freq = FREQ_BCN;
Copy link
Member

@terrillmoore terrillmoore Oct 22, 2019 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

We need to implement MCMD_BeaconFreqReq at some point. When we do that, the FREQ_BCN can be overridden; so we need to get this from a data structure (eventually). We can introduce a new class B data structure to hold the beacon frequency and other eacon params.

BTW: we should remove CHNL_BCN altogether from lorabase.h; it should not be used to index LMIC.channels[], because those entries in LMIC.channels[] are used for other things and can't be safely used for the classB beacon.

Since we already have LMIC.ping.*, we could possibly add it there, or simply add LMIC.beacon.freq etc.

For the US, AU, and eventually CN470, we must deal with channel-roaming beacons; for that , we have to use LMIC.bcnChnl, but that is all done in the regional file. LMIC.bcnChnl can be moved into the "US-like" area of LMIC.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added first stage (static beacon frequency) for AS923, EU868, IN866 and KR920 as part of major changes for #208.

LMIC.rps = setIh(setNocrc(dndr2rps((dr_t)DR_BCN), 1), LEN_BCN);
}
#endif // !DISABLE_BEACONS
Expand Down