test

scripts/rd-network-impairment.sh

@@ -0,0 +1,85 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+usage() {
+  echo "Usage: $0 apply <interface> <wan|constrained|harsh>"
+  echo "       $0 status <interface>"
+  echo "       $0 clear <interface>"
+  echo
+  echo "Profiles:"
+  echo "  wan          20 mbit, 40 ms ± 10 ms, 0.5% loss"
+  echo "  constrained   8 mbit, 80 ms ± 25 ms, 2.0% loss"
+  echo "  harsh         3 mbit, 150 ms ± 50 ms, 5.0% loss"
+}
+
+if [[ $# -lt 2 ]]; then
+  usage
+  exit 2
+fi
+
+command_name=$1
+interface_name=$2
+
+if [[ ! $interface_name =~ ^[a-zA-Z0-9_.:-]+$ ]] || [[ ! -d "/sys/class/net/$interface_name" ]]; then
+  echo "Unknown or invalid network interface: $interface_name" >&2
+  exit 2
+fi
+
+if [[ $interface_name == "lo" && ${OVERLORD_NETEM_ALLOW_LOOPBACK:-0} != "1" ]]; then
+  echo "Refusing to modify loopback without OVERLORD_NETEM_ALLOW_LOOPBACK=1" >&2
+  exit 2
+fi
+
+if ! command -v tc >/dev/null 2>&1; then
+  echo "tc was not found. Install the iproute2 package." >&2
+  exit 1
+fi
+
+case $command_name in
+  status)
+    tc qdisc show dev "$interface_name"
+    ;;
+  clear)
+    if [[ ${EUID:-$(id -u)} -ne 0 ]]; then
+      echo "clear requires root (run with sudo)." >&2
+      exit 1
+    fi
+    tc qdisc del dev "$interface_name" root 2>/dev/null || true
+    echo "Cleared network impairment from $interface_name"
+    ;;
+  apply)
+    if [[ $# -ne 3 ]]; then
+      usage
+      exit 2
+    fi
+    if [[ ${EUID:-$(id -u)} -ne 0 ]]; then
+      echo "apply requires root (run with sudo)." >&2
+      exit 1
+    fi
+    profile_name=$3
+    case $profile_name in
+      wan)
+        rate=20mbit; delay=40ms; jitter=10ms; loss=0.5%
+        ;;
+      constrained)
+        rate=8mbit; delay=80ms; jitter=25ms; loss=2%
+        ;;
+      harsh)
+        rate=3mbit; delay=150ms; jitter=50ms; loss=5%
+        ;;
+      *)
+        echo "Unknown impairment profile: $profile_name" >&2
+        usage
+        exit 2
+        ;;
+    esac
+    tc qdisc replace dev "$interface_name" root netem \
+      delay "$delay" "$jitter" distribution normal loss random "$loss" rate "$rate"
+    echo "Applied $profile_name impairment to $interface_name"
+    tc qdisc show dev "$interface_name"
+    ;;
+  *)
+    usage
+    exit 2
+    ;;
+esac