From 5a4fab25066e77dec48bb8cac11799edce8be67f Mon Sep 17 00:00:00 2001
From: geeksville <kevinh@geeksville.com>
Date: Fri, 1 May 2020 08:51:53 -0700
Subject: [PATCH] start msg sequence numbers with a random number each boot

---
 docs/software/nrf52-TODO.md  |  3 ++-
 src/esp32/main-esp32.cpp     |  2 ++
 src/mesh/MeshService.cpp     | 10 ++++++++--
 src/nrf52/main-nrf52.cpp     |  1 +
 src/rf95/RadioLibInterface.h |  2 +-
 5 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/docs/software/nrf52-TODO.md b/docs/software/nrf52-TODO.md
index 323aa1e0e..17cf83652 100644
--- a/docs/software/nrf52-TODO.md
+++ b/docs/software/nrf52-TODO.md
@@ -5,7 +5,6 @@
 Minimum items needed to make sure hardware is good.
 
 - add a hard fault handler
-- at boot we are starting our message IDs at 1, rather we should start them at a random number. also, seed random based on timer. this could be the cause of our first message not seen bug. 
 - use "variants" to get all gpio bindings
 - plug in correct variants for the real board
 - Use the PMU driver on real hardware
@@ -57,6 +56,7 @@ Needed to be fully functional at least at the same level of the ESP32 boards. At
 - currently using soft device SD140, is that ideal?
 - turn on the watchdog timer, require servicing from key application threads
 - install a hardfault handler for null ptrs (if one isn't already installed)
+- nrf52setup should call randomSeed(tbd)
 
 ## Things to do 'someday'
 
@@ -97,6 +97,7 @@ Nice ideas worth considering someday...
 - DONE track rxbad, rxgood, txgood
 - DONE neg 7 error code from receive
 - DONE remove unused sx1262 lib from github
+- at boot we are starting our message IDs at 1, rather we should start them at a random number. also, seed random based on timer. this could be the cause of our first message not seen bug.
 
 ```
 
diff --git a/src/esp32/main-esp32.cpp b/src/esp32/main-esp32.cpp
index b15d60732..48af9b998 100644
--- a/src/esp32/main-esp32.cpp
+++ b/src/esp32/main-esp32.cpp
@@ -164,6 +164,8 @@ void axp192Init()
 
 void esp32Setup()
 {
+    randomSeed(esp_random()); // ESP docs say this is fairly random
+
 #ifdef AXP192_SLAVE_ADDRESS
     axp192Init();
 #endif
diff --git a/src/mesh/MeshService.cpp b/src/mesh/MeshService.cpp
index d0e693ada..873d17eca 100644
--- a/src/mesh/MeshService.cpp
+++ b/src/mesh/MeshService.cpp
@@ -61,8 +61,14 @@ static Periodic sendOwnerPeriod(sendOwnerCb);
 // FIXME, move this someplace better
 PacketId generatePacketId()
 {
-    static uint32_t i __attribute__((
-        section(".noinit"))); // We try to keep this in noinit so that hopefully it keeps increasing even across reboots
+    static uint32_t i; // Note: trying to keep this in noinit didn't help for working across reboots
+    static bool didInit = false;
+
+    if (!didInit) {
+        didInit = true;
+        i = random(0, NUM_PACKET_ID +
+                          1); // pick a random initial sequence number at boot (to prevent repeated reboots always starting at 0)
+    }
 
     i++;
     return (i % NUM_PACKET_ID) + 1; // return number between 1 and 255
diff --git a/src/nrf52/main-nrf52.cpp b/src/nrf52/main-nrf52.cpp
index 255b80101..0fe2c8d96 100644
--- a/src/nrf52/main-nrf52.cpp
+++ b/src/nrf52/main-nrf52.cpp
@@ -67,4 +67,5 @@ void nrf52Setup()
 {
     // Not yet on board
     // pmu.init();
+    DEBUG_MSG("FIXME, need to call randomSeed on nrf52!\n");
 }
\ No newline at end of file
diff --git a/src/rf95/RadioLibInterface.h b/src/rf95/RadioLibInterface.h
index bf5e20f7c..1e42aedb0 100644
--- a/src/rf95/RadioLibInterface.h
+++ b/src/rf95/RadioLibInterface.h
@@ -101,7 +101,7 @@ class RadioLibInterface : public RadioInterface
     void applyModemConfig();
 
     /** Could we send right now (i.e. either not actively receiving or transmitting)? */
-    virtual bool canSendImmediately();
+    bool canSendImmediately();
 
     /** are we actively receiving a packet (only called during receiving state) */
     virtual bool isActivelyReceiving() = 0;