feat: guestOS docker config (#3)

microagent-network-up.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+wait_for_primary_interface() {
+  local attempt=0
+  while [ "$attempt" -lt 100 ]; do
+    local iface
+    iface="$(find /sys/class/net -mindepth 1 -maxdepth 1 -printf '%f\n' | grep -v '^lo$' | head -n1 || true)"
+    if [ -n "$iface" ]; then
+      printf '%s\n' "$iface"
+      return 0
+    fi
+    attempt=$((attempt + 1))
+    sleep 0.1
+  done
+  return 1
+}
+
+u32_to_ipv4() {
+  local value="$1"
+  printf '%d.%d.%d.%d' \
+    $(((value >> 24) & 255)) \
+    $(((value >> 16) & 255)) \
+    $(((value >> 8) & 255)) \
+    $((value & 255))
+}
+
+primary_iface="$(wait_for_primary_interface)"
+mac="$(cat "/sys/class/net/${primary_iface}/address")"
+IFS=':' read -r mac0 mac1 mac2 mac3 mac4 mac5 <<<"$mac"
+
+guest_u32=$((((16#${mac2}) << 24) | ((16#${mac3}) << 16) | ((16#${mac4}) << 8) | (16#${mac5})))
+gateway_u32=$((guest_u32 - 1))
+
+guest_ip="$(u32_to_ipv4 "$guest_u32")"
+gateway_ip="$(u32_to_ipv4 "$gateway_u32")"
+
+ip link set dev lo up
+ip link set dev "$primary_iface" up
+ip addr replace "${guest_ip}/30" dev "$primary_iface"
+ip route replace default via "$gateway_ip" dev "$primary_iface"
+
+if [ -w /etc/resolv.conf ]; then
+  cat >/etc/resolv.conf <<'EOF'
+nameserver 1.1.1.1
+nameserver 8.8.8.8
+EOF
+fi