Configure IP address, NTP, SSH

- Build userspace (Buildroot) in Thumb2 mode
- Set MAC address from EEPROM on boot
- Load SSH host key from SD card
- Enable DHCP
- Configure NTP (using DHCP if possible)

os/11_build_buildroot.sh

@@ -2,7 +2,7 @@
 
 set -e
 
-BUILDROOT_DIR="buildroot-2023.02.8"
+. script_env
 
 make -C "$BUILDROOT_DIR" distclean
 
@@ -10,4 +10,3 @@ cp -a config/buildroot_puzzlefw_defconfig "$BUILDROOT_DIR/.config"
 make -C "$BUILDROOT_DIR" olddefconfig
 make -C "$BUILDROOT_DIR"
 
-ln -sf "$BUILDROOT_DIR" buildroot

os/22_prepare_sdcard.sh

@@ -28,3 +28,8 @@ cp -a "$BUILDROOT_DIR/output/images/rootfs.cpio.uboot" "$SDCARD_DIR"
 # Wrap U-Boot script in image file
 $MKIMAGE -A arm -T script -d config/uboot_script.txt "$SDCARD_DIR/boot.scr"
 
+# Create SSH host key for embedded system
+if [ ! -f "$SDCARD_DIR/dropbear_ed25519_host_key" ]; then
+    dropbearkey -t ed25519 -f "$SDCARD_DIR/dropbear_ed25519_host_key"
+fi
+

os/buildroot_overlay/etc/chrony.conf

@@ -0,0 +1,3 @@
+include /etc/chrony_dhcp.conf
+pool pool.ntp.org iburst
+makestep 0.1 3

os/buildroot_overlay/etc/init.d/S03set_ethaddr.sh

@@ -0,0 +1,44 @@
+#!/bin/sh
+#
+# Set Ethernet MAC address based on EEPROM settings.
+#
+
+start() {
+
+    # Read "ethaddr" variable from U-Boot environment in EEPROM.
+    #
+    # Environment starts at address 0x1800 and is 1024 bytes long.
+    # The environment consists of "key=value" pairs, separated by 0x00 bytes.
+    #
+    ethaddr_pair="$( dd if=/sys/bus/i2c/devices/0-0050/eeprom bs=1k skip=6 count=1 status=none | tr '\000' '\n' | grep ^ethaddr= )"
+
+    if [ -z "${ethaddr_pair}" ]; then
+        echo "ERROR: ethaddr not found in EEPROM enviroment" >&2
+        exit 1
+    fi
+
+    ethaddr="${ethaddr_pair#ethaddr=}"
+
+    # Check that ethaddr variable is well-formed.
+    if [ -n "${ethaddr##[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]}" ]; then
+        echo "ERROR: Invalid ethaddr found in EEPROM enviroment" >&2
+        exit 1
+    fi
+
+    echo "Setting MAC address ${ethaddr}"
+
+    # Configure MAC address
+    ip link set dev eth0 addr ${ethaddr}
+}
+
+case "$1" in
+  start)
+    start
+    ;;
+  stop|restart|reload)
+    ;;
+  *)
+    echo "Usage: $0 start"
+    exit 1
+esac
+

os/buildroot_overlay/etc/init.d/S10prepare_dropbear.sh

@@ -0,0 +1,44 @@
+#!/bin/sh
+#
+# Load SSH host key from SD card.
+#
+
+start() {
+
+    # If host key exists, do nothing.
+    [ -f /etc/dropbear/dropbear_ed25519_host_key ] && return
+
+    # If /etc/dropbear is a symlink, delete it.
+    [ -L /etc/dropbear ] && rm /etc/dropbear
+
+    # Create directory /etc/dropbear if it does not exist.
+    mkdir -p /etc/dropbear
+
+    # Try to copy SSH host key from SD card.
+    mkdir -p /mnt/tmp_sdcard
+    mount -t vfat -o fmask=0177 -r /dev/mmcblk0p1 /mnt/tmp_sdcard
+
+    if ! cp -p /mnt/tmp_sdcard/dropbear_ed25519_host_key /etc/dropbear ; then
+        echo "WARNING: Failed to load SSH host key from SD card" >&2
+        umount /mnt/tmp_sdcard
+        rmdir /mnt/tmp_sdcard
+        exit 1
+    fi
+
+    umount /mnt/tmp_sdcard
+    rmdir /mnt/tmp_sdcard
+
+    chmod 0600 /etc/dropbear/dropbear_ed25519_host_key
+}
+
+case "$1" in
+  start)
+    start
+    ;;
+  stop|restart|reload)
+    ;;
+  *)
+    echo "Usage: $0 start"
+    exit 1
+esac
+

os/buildroot_overlay/etc/network/interfaces

@@ -0,0 +1,6 @@
+
+auto lo
+iface lo inet loopback
+
+auto eth0
+iface eth0 inet dhcp

os/buildroot_overlay/usr/share/udhcpc/default.script.d/ntp_chrony.script

@@ -0,0 +1,29 @@
+#!/bin/sh
+#
+# Configure chrony to use NTP server advertised by DHCP server.
+#
+
+configure_ntp() {
+
+    # Do nothing if the DHCP server does not advertise any NTP server.
+    [ -z "$ntpsrv" ] && return
+
+    # Write config snippet with NTP servers.
+    for srv in $ntpsrv ; do
+        echo "server $srv iburst"
+    done > /etc/chrony_dhcp.conf.new
+
+    # Compare to currently configured NTP servers.
+    if ! diff -q /etc/chrony_dhcp.conf /etc/chrony_dhcp.conf.new >/dev/null ; then
+        # Update configuration and restart Chrony.
+        mv /etc/chrony_dhcp.conf.new /etc/chrony_dhcp.conf
+        /etc/init.d/S49chrony reload
+    fi
+}
+
+case "$1" in
+    renew|bound)
+        configure_ntp
+        ;;
+esac
+

os/config/buildroot_puzzlefw_defconfig

@@ -2,18 +2,24 @@ BR2_arm=y
 BR2_cortex_a9=y
 BR2_ARM_ENABLE_NEON=y
 BR2_ARM_ENABLE_VFP=y
+BR2_ARM_INSTRUCTIONS_THUMB2=y
 BR2_TOOLCHAIN_BUILDROOT_UCLIBC=y
 BR2_TOOLCHAIN_BUILDROOT_WCHAR=y
 BR2_BINUTILS_VERSION_2_39_X=y
 BR2_GCC_VERSION_12_X=y
 BR2_TOOLCHAIN_BUILDROOT_CXX=y
 BR2_TARGET_GENERIC_HOSTNAME="pitaya"
+BR2_TARGET_GENERIC_ISSUE="Welcome to Red Pitaya PuzzleFW"
 BR2_TARGET_GENERIC_ROOT_PASSWD="root"
+BR2_ROOTFS_OVERLAY="../buildroot_overlay"
 BR2_PACKAGE_XZ=y
 BR2_PACKAGE_ZIP=y
 BR2_PACKAGE_MEMSTAT=y
 BR2_PACKAGE_STRACE=y
 BR2_PACKAGE_TINYMEMBENCH=y
+BR2_PACKAGE_DOSFSTOOLS=y
+BR2_PACKAGE_DOSFSTOOLS_FSCK_FAT=y
+BR2_PACKAGE_DOSFSTOOLS_MKFS_FAT=y
 BR2_PACKAGE_E2FSPROGS=y
 BR2_PACKAGE_LIBUIO=y
 BR2_PACKAGE_LSUIO=y
@@ -46,6 +52,7 @@ BR2_PACKAGE_NGINX=y
 # BR2_PACKAGE_NGINX_HTTP_UPSTREAM_KEEPALIVE_MODULE is not set
 # BR2_PACKAGE_NGINX_HTTP_UPSTREAM_RANDOM_MODULE is not set
 # BR2_PACKAGE_NGINX_HTTP_UPSTREAM_ZONE_MODULE is not set
+BR2_PACKAGE_PHYTOOL=y
 # BR2_PACKAGE_URANDOM_SCRIPTS is not set
 BR2_PACKAGE_XXHASH=y
 BR2_PACKAGE_ATOP=y