新增 check_ipv6_precedence_warning 函数以检查 IPv6 优先级配置并发出警告

1.sh

@@ -174,6 +174,48 @@ detect_cn_network() {
   return 1
 }
 
+check_ipv6_precedence_warning() {
+  local gai_conf=/etc/gai.conf
+  local ipv6_check_url="https://api64.ipify.org"
+  local has_external_ipv6=false
+
+  # Force an IPv6-only request so an IPv4 connection cannot count as success.
+  if command -v curl >/dev/null 2>&1; then
+    if curl -6 --noproxy '*' -fsS --connect-timeout 3 --max-time 5 \
+      "$ipv6_check_url" >/dev/null 2>&1; then
+      has_external_ipv6=true
+    fi
+  elif command -v wget >/dev/null 2>&1; then
+    if wget -6 -q -T 5 -O /dev/null "$ipv6_check_url" >/dev/null 2>&1; then
+      has_external_ipv6=true
+    fi
+  fi
+
+  [ "$has_external_ipv6" = true ] && return 0
+  [ -r "$gai_conf" ] || return 0
+
+  # Warn only when the matching rule exists in a commented form and is not
+  # overridden by an active copy of the same rule.
+  if awk '
+    {
+      line = $0
+      sub(/^[[:space:]]*/, "", line)
+      is_comment = (line ~ /^#/)
+      sub(/^#[[:space:]]*/, "", line)
+      if (line ~ /^precedence[[:space:]]+::ffff:0:0\/96[[:space:]]+100([[:space:]]|$)/) {
+        if (is_comment) {
+          commented = 1
+        } else {
+          active = 1
+        }
+      }
+    }
+    END { exit !(commented && !active) }
+  ' "$gai_conf"; then
+    print_yellow "警告：本机没有外网 IPv6，且 /etc/gai.conf 中 precedence ::ffff:0:0/96 100 仍处于注释状态。"
+  fi
+}
+
 check_container_runtime() {
   if [ -x "$(command -v podman)" ]; then
     echo "检测到 Podman 已安装，跳过 Docker 相关配置"
@@ -332,5 +374,6 @@ install_docker
 # start_watchtower
 # install_zram
 sysctl_config
+check_ipv6_precedence_warning
 
 # source <(curl -fsSL scripts.oo1.dev/nezha-v1.sh)