From 99561f2e472b910b33499371a0f8e3c12e9773b9 Mon Sep 17 00:00:00 2001
From: Orne Brocaar <info@brocaar.com>
Date: Mon, 9 Oct 2023 11:33:04 +0100
Subject: [PATCH] Reset uplink_adr_history in case of DR / TxPower / NbTrans
 change.

---
 api/proto/internal/internal.proto     |  4 ++++
 chirpstack/src/maccommand/link_adr.rs | 14 +++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/api/proto/internal/internal.proto b/api/proto/internal/internal.proto
index e3483e1b..a01466f1 100644
--- a/api/proto/internal/internal.proto
+++ b/api/proto/internal/internal.proto
@@ -106,6 +106,10 @@ message DeviceSession {
   DeviceSession pending_rejoin_device_session = 29;
 
   // Uplink history for ADR (last 20 uplink transmissions).
+  // This table is reset in case one of parameters has changed:
+  //   * DR
+  //   * TxPower
+  //   * NbTrans
   repeated UplinkAdrHistory uplink_adr_history = 30;
 
   // Mac-command error count.
diff --git a/chirpstack/src/maccommand/link_adr.rs b/chirpstack/src/maccommand/link_adr.rs
index 65c2bc71..cfacc499 100644
--- a/chirpstack/src/maccommand/link_adr.rs
+++ b/chirpstack/src/maccommand/link_adr.rs
@@ -53,7 +53,7 @@ pub fn handle(
     if ch_mask_ack && dr_ack && tx_power_ack {
         // The device acked all request (channel-mask, data-rate and power),
         // in this case we update the device-session with all the requested
-        // modifcations.
+        // modifications.
 
         // reset the error counter
         ds.mac_command_error_count
@@ -69,6 +69,14 @@ pub fn handle(
             )
             .context("Get enabled uplink-channels for LinkADRReq payloads")?;
 
+        // Reset the uplink ADR history table in case one of the TxPower, DR or NbTrans parameters have changed.
+        if ds.tx_power_index != link_adr_req.tx_power as u32
+            || ds.dr != link_adr_req.dr as u32
+            || ds.nb_trans != link_adr_req.redundancy.nb_rep as u32
+        {
+            ds.uplink_adr_history = vec![];
+        }
+
         ds.tx_power_index = link_adr_req.tx_power as u32;
         ds.dr = link_adr_req.dr as u32;
         ds.nb_trans = link_adr_req.redundancy.nb_rep as u32;
@@ -174,6 +182,9 @@ pub mod test {
                     .iter()
                     .cloned()
                     .collect(),
+                    uplink_adr_history: vec![internal::UplinkAdrHistory {
+                        ..Default::default()
+                    }],
                 ..Default::default()
             },
             link_adr_req: Some(lrwn::LinkADRReqPayload {
@@ -197,6 +208,7 @@ pub mod test {
                 nb_trans: 2,
                 dr: 5,
                 mac_command_error_count: HashMap::new(),
+                uplink_adr_history: vec![],
                 ..Default::default()
             },
             expected_error: None,