Add resilient dual-radio network failover

2026-07-31 20:24:34 +02:00
parent 0a0dae144c
commit 6940cfb3a8
19 changed files with 857 additions and 11 deletions
@@ -0,0 +1,94 @@
+#!/usr/bin/env bash
+set -Eeuo pipefail
+
+CONFIG_FILE="/etc/pi-car-companion/companion.env"
+HOTSPOT_CONNECTION="pi-car-hotspot"
+HOTSPOT_INTERFACE="wlan0"
+UPSTREAM_INTERFACE="wlan1"
+HOTSPOT_ADDRESS="10.42.0.1/24"
+HOTSPOT_SSID="${1:-MG4-Companion}"
+
+if [[ ${EUID} -ne 0 ]]; then
+  exec sudo -- "$0" "$@"
+fi
+if [[ ! -f "${CONFIG_FILE}" ]]; then
+  echo "Pi Car Companion is not installed. Run install.sh first." >&2
+  exit 1
+fi
+if [[ ! "${HOTSPOT_SSID}" =~ ^[[:alnum:]_.-]{1,32}$ ]]; then
+  echo "The hotspot SSID must contain 1-32 letters, numbers, dots, hyphens, or underscores." >&2
+  exit 1
+fi
+if [[ "$(nmcli --get-values GENERAL.STATE device show "${UPSTREAM_INTERFACE}" 2>/dev/null || true)" != 100* ]]; then
+  echo "${UPSTREAM_INTERFACE} must be connected to a saved upstream network before failover is enabled." >&2
+  echo "Connect it first with: sudo nmcli --ask device wifi connect '<SSID>' ifname ${UPSTREAM_INTERFACE} name upstream-home" >&2
+  exit 1
+fi
+
+read -r -s -p "Password for ${HOTSPOT_SSID} (8-63 characters): " hotspot_password
+echo
+if (( ${#hotspot_password} < 8 || ${#hotspot_password} > 63 )) || [[ ! "${hotspot_password}" =~ ^[[:alnum:]_.-]+$ ]]; then
+  echo "The hotspot password must contain 8-63 letters, numbers, dots, hyphens, or underscores." >&2
+  exit 1
+fi
+
+hotspot_file="/etc/NetworkManager/system-connections/${HOTSPOT_CONNECTION}.nmconnection"
+hotspot_uuid="$(uuidgen)"
+temporary_file="$(mktemp)"
+trap 'rm -f -- "${temporary_file}"' EXIT
+cat > "${temporary_file}" <<EOF
+[connection]
+id=${HOTSPOT_CONNECTION}
+uuid=${hotspot_uuid}
+type=wifi
+interface-name=${HOTSPOT_INTERFACE}
+autoconnect=false
+
+[wifi]
+band=bg
+mode=ap
+ssid=${HOTSPOT_SSID}
+
+[wifi-security]
+key-mgmt=wpa-psk
+psk=${hotspot_password}
+
+[ipv4]
+address1=${HOTSPOT_ADDRESS}
+method=shared
+
+[ipv6]
+method=disabled
+EOF
+if nmcli --get-values NAME connection show | grep -Fxq "${HOTSPOT_CONNECTION}"; then
+  nmcli connection delete "${HOTSPOT_CONNECTION}"
+fi
+install -m 0600 -o root -g root "${temporary_file}" "${hotspot_file}"
+nmcli connection load "${hotspot_file}"
+hotspot_password=""
+
+set_env() {
+  local key="$1"
+  local value="$2"
+  if grep -q "^${key}=" "${CONFIG_FILE}"; then
+    sed -i "s|^${key}=.*|${key}=${value}|" "${CONFIG_FILE}"
+  else
+    printf '%s=%s\n' "${key}" "${value}" >> "${CONFIG_FILE}"
+  fi
+}
+
+set_env NETWORK_MANAGER_ENABLED true
+set_env NETWORK_HOTSPOT_INTERFACE "${HOTSPOT_INTERFACE}"
+set_env NETWORK_UPSTREAM_INTERFACE "${UPSTREAM_INTERFACE}"
+set_env NETWORK_HOTSPOT_CONNECTION "${HOTSPOT_CONNECTION}"
+set_env NETWORK_PROBE_TIMEOUT_SECONDS 60
+set_env NETWORK_STABILITY_SECONDS 10
+set_env NETWORK_POLL_SECONDS 5
+
+systemctl enable --now pi-car-companion-network.service
+systemctl restart pi-car-companion.service
+
+upstream_address="$(nmcli --get-values IP4.ADDRESS device show "${UPSTREAM_INTERFACE}" | head -n 1)"
+echo "Network failover is enabled."
+echo "The dashboard will remain reachable through ${UPSTREAM_INTERFACE} at ${upstream_address:-its current address}."
+echo "The car hotspot is ${HOTSPOT_SSID} and its dashboard address is http://10.42.0.1:8787."