toss in gateway-monitor

Dockerfile

@@ -2,4 +2,7 @@ FROM debian:bullseye-slim
 RUN apt update && apt -y --no-install-recommends install \
     iproute2 && \
     rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
+WORKDIR /usr/src/app
+COPY ./gateway-monitor.sh ./
 CMD ["/usr/src/app/gateways-monitor.sh"]

README.md

 # gateways-monitor
 
+## Variable and source
+
+`/usr/src/app/route-plans`: `ROUTE_PLANS`

gateway-monitor.sh

+#!/bin/bash
+
+# ROUTE_PLANS
+source /usr/src/app/route-plans
+
+while read dst others
+do
+    if [[ "$dst" == "10.198.0."* ]] && [[ "$others" == *"proto babel"* ]]
+    then
+        # 读 babeld 路由
+        declare -A routes
+        while read -r dst others
+        do
+            routes["$dst"]="$others"
+        done < <( ip route show proto babel root 10.198.0.0/24 )
+
+        # 取最优路由并写进系统路由表
+        # 这个循环内所有 echo 的东西都会打给 iproute2。打调试信息要用 stderr
+        for table in "${!ROUTE_PLANS[@]}"; do
+            best_dev=
+            best_metric=65535
+            for dst in ${ROUTE_PLANS["$table"]}
+            do
+                if [[ -v "routes[$dst]" ]]
+                then
+                    # 只需要 dev 和 metric，其余的丢弃，目前的体系全都是 L3 口，仅用 dev 就可以路由
+                    # 这里假设了 dev 和 metric 的位置。babeld 生成的路由表是符合这个规律的
+                    read _ _ _ dev _ metric _ <<< ${routes[$dst]}
+                    if (( metric < best_metric )); then
+                        best_metric="$metric"
+                        best_dev="$dev"
+                    fi
+                fi
+            done
+            if [ -z "$best_dev" ]
+            then
+                echo "route flush table $table"
+            else
+                echo "route replace default dev $best_dev table $table"
+            fi
+        done # | ip -batch -
+    fi
+done < <( ip monitor route )