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Don't use DF18 when updating the known-Mode-S-address set.

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DF18 transponders don't necessarily do Mode S, so we shouldn't assume
that Mode S messages from that address are valid merely because we
heard a DF18. If it really is Mode S equipped, we should hear a
DF11 at some point.
This commit is contained in:
Oliver Jowett 2019-01-21 20:11:12 +00:00
parent 9c124b3f2b
commit c05aea65a4
1 changed files with 4 additions and 4 deletions
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8
mode_s.c
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@ -681,12 +681,12 @@ int decodeModesMessage(struct modesMessage *mm, unsigned char *msg)
mm->airground = AG_UNCERTAIN;
}
if (!mm->correctedbits && (mm->msgtype == 17 || mm->msgtype == 18 || (mm->msgtype == 11 && mm->IID == 0))) {
// No CRC errors seen, and either it was an DF17/18 extended squitter
if (!mm->correctedbits && (mm->msgtype == 17 || (mm->msgtype == 11 && mm->IID == 0))) {
// No CRC errors seen, and either it was an DF17 extended squitter
// or a DF11 acquisition squitter with II = 0. We probably have the right address.
// We wait until here to do this as we may have needed to decode an ES to note
// the type of address in DF18 messages.
// Don't do this for DF18, as a DF18 transmitter doesn't necessarily have a
// Mode S transponder.
// NB this is the only place that adds addresses!
icaoFilterAdd(mm->addr);