meta-google: gbmc-ip-monitor: Add package
Add a daemon that monitors all link / addr / route changes on a system,
and runs a set of installed hooks to perform customized behavior when
these changes occur.
Change-Id: Id2a6b7dc2534ebae1beca7135528a6e1e4eada57
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/meta-google/recipes-google/networking/files/gbmc-ip-monitor.sh b/meta-google/recipes-google/networking/files/gbmc-ip-monitor.sh
new file mode 100755
index 0000000..baeff9a
--- /dev/null
+++ b/meta-google/recipes-google/networking/files/gbmc-ip-monitor.sh
@@ -0,0 +1,122 @@
+#!/bin/bash
+# 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
+ source "$conf"
+done
+
+gbmc_ip_monitor_run_hooks() {
+ local hook
+ for hook in "${GBMC_IP_MONITOR_HOOKS[@]}"; do
+ "$hook" || continue
+ done
+}
+
+gbmc_ip_monitor_generate_init() {
+ ip link | sed 's,^[^ ],[LINK]\0,'
+ local intf=
+ local line
+ while read line; do
+ [[ "$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_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:]]+(brd[[:space:]]+[^ ]+[[:space:]]+)?'
+ scope_re='scope[[:space:]]+([^ ]+)[[:space:]]*(.*)'
+ combined_re="${pfx_re}${intf_re}${fam_re}${addr_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[6]}"
+ flags="${BASH_REMATCH[7]}"
+ elif [[ "$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="${BASH_REMATCH[2]}"
+ read line || break
+ data=($line)
+ mac="${data[1]}"
+ else
+ return 2
+ fi
+}
+
+cleanup() {
+ local st="$?"
+ trap - HUP INT QUIT ABRT TERM EXIT
+ jobs -l -p | xargs -r kill || true
+ exit $st
+}
+trap cleanup HUP INT QUIT ABRT TERM EXIT
+
+return 0 2>/dev/null
+
+while read line; do
+ gbmc_ip_monitor_parse_line || continue
+ gbmc_ip_monitor_run_hooks || continue
+ if [ "$change" = 'init' ]; then
+ systemd-notify --ready
+ fi
+done < <(gbmc_ip_monitor_generate_init; exec ip monitor link addr route label)