Initial commit

meta-google/recipes-google/networking/files/gbmc-ip-monitor.sh

@@ -0,0 +1,145 @@
+#!/bin/bash
+# shellcheck disable=SC2034
+# shellcheck disable=SC2317
+# Copyright 2021 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# A list of functions which get executed for each netlink event received.
+# These are configured by the files included below.
+GBMC_IP_MONITOR_HOOKS=()
+
+# Load configurations from a known location in the filesystem to populate
+# hooks that are executed after each event.
+shopt -s nullglob
+for conf in /usr/share/gbmc-ip-monitor/*.sh; do
+  # shellcheck source=/dev/null
+  source "$conf"
+done
+
+gbmc_ip_monitor_run_hooks() {
+  local hook
+  for hook in "${GBMC_IP_MONITOR_HOOKS[@]}"; do
+    "$hook" || continue
+  done
+}
+
+gbmc_ip_monitor_generate_init() {
+  ip link | sed 's,^[^ ],[LINK]\0,'
+  local intf=
+  local line
+  while read -r line; do
+    [[ "$line" =~ ^([0-9]+:[[:space:]][^:]+) ]] && intf="${BASH_REMATCH[1]}"
+    [[ "$line" =~ ^[[:space:]]*inet ]] && echo "[ADDR]$intf $line"
+  done < <(ip addr)
+  ip -4 route | sed 's,^,[ROUTE],'
+  ip -6 route | sed 's,^,[ROUTE],'
+  echo '[INIT]'
+}
+
+GBMC_IP_MONITOR_DEFER_OUTSTANDING=
+gbmc_ip_monitor_defer_() {
+  sleep 1
+  printf '[DEFER]\n' >&"$GBMC_IP_MONITOR_DEFER"
+}
+gbmc_ip_monitor_defer() {
+  [ -z "$GBMC_IP_MONITOR_DEFER_OUTSTANDING" ] || return 0
+  gbmc_ip_monitor_defer_ &
+  GBMC_IP_MONITOR_DEFER_OUTSTANDING=1
+}
+
+gbmc_ip_monitor_parse_line() {
+  local line="$1"
+  if [[ "$line" == '[INIT]'* ]]; then
+    change=init
+    echo "Initialized" >&2
+  elif [[ "$line" == '[ADDR]'* ]]; then
+    change=addr
+    action=add
+    pfx_re='^\[ADDR\](Deleted )?[0-9]+:[[:space:]]*'
+    intf_re='([^ ]+)[[:space:]]+'
+    fam_re='([^ ]+)[[:space:]]+'
+    addr_re='([^/]+)/[0-9]+[[:space:]]+'
+    metric_re='(metric[[:space:]]+[^ ]+[[:space:]]+)?'
+    brd_re='(brd[[:space:]]+[^ ]+[[:space:]]+)?'
+    scope_re='scope[[:space:]]+([^ ]+)[[:space:]]*(.*)'
+    combined_re="${pfx_re}${intf_re}${fam_re}${addr_re}${metric_re}${brd_re}${scope_re}"
+    if ! [[ "$line" =~ ${combined_re} ]]; then
+      echo "Failed to parse addr: $line" >&2
+      return 1
+    fi
+    if [ -n "${BASH_REMATCH[1]}" ]; then
+      action=del
+    fi
+    intf="${BASH_REMATCH[2]}"
+    fam="${BASH_REMATCH[3]}"
+    ip="${BASH_REMATCH[4]}"
+    scope="${BASH_REMATCH[7]}"
+    flags="${BASH_REMATCH[8]}"
+  elif [[ "$line" == '[ROUTE]'* ]]; then
+    line="${line#[ROUTE]}"
+    change=route
+    action=add
+    if ! [[ "$line" =~ ^\[ROUTE\](Deleted )?(.*)$ ]]; then
+      echo "Failed to parse link: $line" >&2
+      return 1
+    fi
+    if [ -n "${BASH_REMATCH[1]}" ]; then
+      action=del
+    fi
+    route="${BASH_REMATCH[2]}"
+  elif [[ "$line" == '[LINK]'* ]]; then
+    change='link'
+    action=add
+    pfx_re='^\[LINK\](Deleted )?[0-9]+:[[:space:]]*'
+    intf_re='([^:]+):[[:space:]]+'
+    if ! [[ "$line" =~ ${pfx_re}${intf_re} ]]; then
+      echo "Failed to parse link: $line" >&2
+      return 1
+    fi
+    if [ -n "${BASH_REMATCH[1]}" ]; then
+      action=del
+    fi
+    intf="${BASH_REMATCH[2]}"
+    read -ra data || return
+    mac="${data[1]}"
+  elif [[ "$line" == '[DEFER]'* ]]; then
+    GBMC_IP_MONITOR_DEFER_OUTSTANDING=
+    change=defer
+  else
+    return 2
+  fi
+}
+
+return 0 2>/dev/null
+
+cleanup() {
+  local st="$?"
+  trap - HUP INT QUIT ABRT TERM EXIT
+  jobs -l -p | xargs -r kill || true
+  exit "$st"
+}
+trap cleanup HUP INT QUIT ABRT TERM EXIT
+
+FIFODIR="$(mktemp -d)"
+mkfifo "$FIFODIR"/fifo
+exec {GBMC_IP_MONITOR_DEFER}<>"$FIFODIR"/fifo
+rm -rf "$FIFODIR"
+
+while read -r line; do
+  gbmc_ip_monitor_parse_line "$line" || continue
+  gbmc_ip_monitor_run_hooks || continue
+  if [ "$change" = 'init' ]; then
+    systemd-notify --ready
+  fi
+done < <(gbmc_ip_monitor_generate_init; ip monitor link addr route label & cat <&"$GBMC_IP_MONITOR_DEFER")