capture tap0 with tcpdump in the m33mu freertos echo job

Author: gasbytes

.github/workflows/stm32h563-m33mu-freertos.yml

@@ -17,3 +17,14 @@ jobs:
 
       - name: Run m33mu + DHCP + TCP echo FreeRTOS test
         run: /bin/bash tools/scripts/run-m33mu-ci-in-container.sh stm32h563-m33mu-freertos stm32h563_m33mu_echo_freertos
+
+      - name: Upload tap0 capture + board logs (DEBUG)
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: m33mu-echo-debug
+          path: |
+            /tmp/echo.pcap
+            /tmp/m33mu.log
+            /tmp/echo.log
+          if-no-files-found: warn

tools/scripts/run-m33mu-ci-in-container.sh

@@ -410,6 +410,8 @@ job_echo_freertos() {
   echo "==> Running stm32h563_m33mu_echo_freertos"
   trap cleanup_runtime EXIT
   setup_tap_and_dnsmasq
+  tcpdump -i tap0 -nn -s0 -U -w /tmp/echo.pcap > /tmp/tcpdump.log 2>&1 &
+  printf '%s\n' "$!" > /tmp/tcpdump.pid
   start_m33mu 180 --quit-on-faults
   local ip
   ip="$(wait_for_lease 90)"