For packets with a path set; auto try again if no echo was heard. High Availability Link for Overwhelmed Meshes - Project HALO. Stop the flood

[mikecarper]

This PR adds direct-retry behavior for direct-path traffic when an expected forward echo is not overheard, with link-quality gating that can be configured (5db is the default). So if the SF is 7 then we can expect that -7.5db is the limit; if the link is below -2.5db then this will not try again as the odds of success is low. For busy repeaters this value can be increased to 10 or so; so the retry logic only triggers if the SNR is +2.5 or better. Default value is off. neighbor list is checked first with optional fallback to recently heard repeater prefixes. wait uses 4 times the packet-time equivalent with minimum floor of 200ms

Starts the retry wait window after actual TX complete. Cancels pending retry when a valid forward echo is received.

Covers direct retry target selection for:
- PATH, REQ, RESPONSE, TXT_MSG, ANON_REQ
- ACK
- MULTIPART packets carrying ACK payloads
- TRACE (with existing downstream-hop guard)

Added to the CLI :
- get/set direct.retry.heard on|off
- get/set direct.retry.margin <db>

[mikecarper]

https://analyzer.letsmesh.net/packets?packet_id=671326411

DEBUG: 00:24:20 - 24/4/2026 U direct retry armed (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:24:21 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:24:21 - 24/4/2026 U direct retry resent (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:24:21 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=300)
DEBUG: 00:24:21 - 24/4/2026 U direct retry canceled_echo (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:24:21 - 24/4/2026 U direct retry good (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:24:21 - 24/4/2026 U direct retry armed (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:24:22 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:24:22 - 24/4/2026 U direct retry canceled_echo (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:24:22 - 24/4/2026 U direct retry good (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:24:22 - 24/4/2026 U direct retry armed (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:24:22 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:24:23 - 24/4/2026 U direct retry canceled_echo (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:24:23 - 24/4/2026 U direct retry good (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:24:23 - 24/4/2026 U direct retry armed (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:24:23 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:24:23 - 24/4/2026 U direct retry canceled_echo (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:24:23 - 24/4/2026 U direct retry good (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:24:23 - 24/4/2026 U direct retry armed (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:24:24 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:24:24 - 24/4/2026 U direct retry canceled_echo (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:24:24 - 24/4/2026 U direct retry good (type=9, route=D, payload_len=31, delay=0)

DEBUG: 00:27:55 - 24/4/2026 U direct retry armed (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:27:55 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:27:55 - 24/4/2026 U direct retry canceled_echo (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:27:55 - 24/4/2026 U direct retry good (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:27:55 - 24/4/2026 U direct retry armed (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:27:55 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:27:56 - 24/4/2026 U direct retry canceled_echo (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:27:56 - 24/4/2026 U direct retry good (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:27:56 - 24/4/2026 U direct retry armed (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:27:56 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:27:56 - 24/4/2026 U direct retry resent (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:27:56 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=300)
DEBUG: 00:27:56 - 24/4/2026 U direct retry canceled_echo (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:27:56 - 24/4/2026 U direct retry good (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:27:56 - 24/4/2026 U direct retry armed (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:27:57 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:27:57 - 24/4/2026 U direct retry canceled_echo (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:27:57 - 24/4/2026 U direct retry good (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:27:57 - 24/4/2026 U direct retry armed (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:27:57 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=200)
DEBUG: 00:27:58 - 24/4/2026 U direct retry resent (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:27:58 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=300)
DEBUG: 00:27:58 - 24/4/2026 U direct retry resent (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:27:58 - 24/4/2026 U direct retry queued (type=9, route=D, payload_len=31, delay=400)
DEBUG: 00:27:59 - 24/4/2026 U direct retry canceled_echo (type=9, route=D, payload_len=31, delay=0)
DEBUG: 00:27:59 - 24/4/2026 U direct retry good (type=9, route=D, payload_len=31, delay=0)

This seems to be working

[mikecarper]

G2 Repeater.zip
V4 Repeater.zip

To monitor as meshdebug is set in these 2 firmware builds

in one window
picocom -b 115200 /dev/ttyACM0 --imap lfcrlf --logfile /tmp/mesh.log
in another window

tail -F /tmp/mesh.log | rg --line-buffered "direct retry"

31 hop trace ping pong to one of the more busy repeaters in the area
https://analyzer.letsmesh.net/packets?packet_id=676770803

[mikecarper]

https://github.com/Brent-A/mcsim seems to show this helps; better than showing it hurts.

DM Test

Result 1 (count test: count=1 vs count=6)

• 30 paired seeds, 180s each.
• off: sent 1277, delivered 150, acked 38
• on: sent 1278, delivered 153, acked 39
• Delta: +3 delivered (+2.00%), +1 acked
• Per-seed: better in 1, worse in 0, equal in 29

Result 2 (explicit enable/disable by margin: margin=40 vs margin=0, both count=6)

• 30 paired seeds, 180s each.
• off: sent 1277, delivered 152, acked 38
• on: sent 1278, delivered 153, acked 39
• Delta: +1 delivered (+0.66%), +1 acked