#!/usr/bin/env bash
# ============================================================================
# MAX BBR — BBR 拥塞控制启用 + 网络参数优化
# 原创脚本，自动检测内核支持、启用 BBR、优化 TCP/IP 参数
#
# 风险等级: 🟡 修改系统配置 — 修改 sysctl 参数
# 用法: bash <(curl -fsSL https://dl.unvmax.com/linux/scripts/max-tools/max-bbr.sh)
# ============================================================================

set -e

R='\033[1;31m' G='\033[1;32m' Y='\033[1;33m' B='\033[1;34m'
C='\033[1;36m' M='\033[1;35m' W='\033[1;37m' N='\033[0m'
GR='\033[90m'

echo -e "${B}┌─────────────────────────────────────────────┐${N}"
echo -e "${B}│${N}  ${G}MAX BBR 启用 + 网络参数优化${N}  ${GR}(修改配置)${N}"
echo -e "${B}└─────────────────────────────────────────────┘${N}"
echo

# ── 检测内核版本 ──
kernel=$(uname -r)
echo -e "  ${C}内核版本:${N} ${W}$kernel${N}"

# 检查 BBR 模块是否可用
if modprobe tcp_bbr 2>/dev/null; then
    echo -e "  ${G}✔ tcp_bbr 内核模块可用${N}"
elif lsmod | grep -q tcp_bbr; then
    echo -e "  ${G}✔ tcp_bbr 模块已加载${N}"
else
    echo -e "  ${R}✘ tcp_bbr 模块不可用${N}"
    echo -e "  ${Y}  当前内核可能不支持 BBR，建议升级内核至 4.9+${N}"
    echo -e "  ${Y}  尝试: apt install linux-image-$(uname -r | cut -d. -f1-2)-amd64${N}"
    exit 1
fi

# 检查当前拥塞控制算法
current_cc=$(sysctl -n net.ipv4.tcp_congestion_control 2>/dev/null || echo "unknown")
current_qdisc=$(sysctl -n net.core.default_qdisc 2>/dev/null || echo "unknown")
echo -e "  ${C}当前拥塞控制:${N} ${Y}$current_cc${N}"
echo -e "  ${C}当前队列算法:${N} ${Y}$current_qdisc${N}"
echo

# ── 功能菜单 ──
echo -e "  ${M}请选择操作:${N}"
echo -e "    ${C}1${N}) ${G}启用 BBR + 全面网络优化${N}  ${GR}(推荐)${N}"
echo -e "    ${C}2${N}) ${G}仅启用 BBR${N}  ${GR}(不修改其他网络参数)${N}"
echo -e "    ${C}3${N}) ${Y}查看当前 BBR 状态${N}  ${GR}(只读)${N}"
echo -e "    ${C}4${N}) ${R}关闭 BBR，恢复默认${N}  ${GR}(cubic + pfifo_fast)${N}"
echo -e "    ${C}q${N}) 退出"
echo
read -r -p "$(echo -e "  ${C}选择 (1-4/q): ${N}")" choice

apply_sysctl() {
    local key="$1" val="$2"
    # 写入 /etc/sysctl.d/ 避免直接改 /etc/sysctl.conf
    local confd="/etc/sysctl.d"
    if [ ! -d "$confd" ]; then confd="/etc/sysctl.d"; mkdir -p "$confd" 2>/dev/null || true; fi
    local file="$confd/90-max-bbr.conf"
    # 如果文件已存在且有该 key，用 sed 替换；否则追加
    if grep -q "^$key" "$file" 2>/dev/null; then
        sed -i "s|^$key.*|$key = $val|" "$file"
    else
        echo "$key = $val" >> "$file"
    fi
    sysctl -w "$key=$val" >/dev/null 2>&1 || true
}

case "$choice" in
    1)
        echo -e "\n  ${Y}应用 BBR + 全面网络参数优化...${N}\n"
        
        # 确保 sysctl.d 目录存在
        mkdir -p /etc/sysctl.d 2>/dev/null || true
        
        # BBR 核心设置
        apply_sysctl "net.core.default_qdisc" "fq"
        apply_sysctl "net.ipv4.tcp_congestion_control" "bbr"
        
        # TCP 缓冲区优化 (单位: bytes)
        apply_sysctl "net.core.rmem_default" "262144"       # 默认读缓冲 256KB
        apply_sysctl "net.core.wmem_default" "262144"       # 默认写缓冲 256KB
        apply_sysctl "net.core.rmem_max" "16777216"         # 最大读缓冲 16MB
        apply_sysctl "net.core.wmem_max" "16777216"         # 最大写缓冲 16MB
        apply_sysctl "net.ipv4.tcp_rmem" "4096 131072 16777216"   # TCP 读缓冲: min default max
        apply_sysctl "net.ipv4.tcp_wmem" "4096 65536 16777216"    # TCP 写缓冲: min default max
        
        # TCP 连接优化
        apply_sysctl "net.ipv4.tcp_fastopen" "3"                   # 启用 TFO (client+server)
        apply_sysctl "net.ipv4.tcp_slow_start_after_idle" "0"      # 空闲后不重置 cwnd
        apply_sysctl "net.ipv4.tcp_mtu_probing" "1"                # 启用 MTU 探测
        apply_sysctl "net.ipv4.tcp_sack" "1"                       # 选择性确认
        apply_sysctl "net.ipv4.tcp_window_scaling" "1"             # 窗口缩放
        
        # 连接 backlog 优化
        apply_sysctl "net.core.somaxconn" "65535"                  # 最大连接队列
        apply_sysctl "net.ipv4.tcp_max_syn_backlog" "65535"        # SYN 队列
        apply_sysctl "net.core.netdev_max_backlog" "65535"         # 网卡队列
        
        # 保活与超时 (适合服务器)
        apply_sysctl "net.ipv4.tcp_keepalive_time" "600"           # 保活间隔 10min
        apply_sysctl "net.ipv4.tcp_keepalive_intvl" "30"           # 保活重试间隔
        apply_sysctl "net.ipv4.tcp_keepalive_probes" "3"           # 保活探测次数
        apply_sysctl "net.ipv4.tcp_fin_timeout" "15"               # FIN 超时
        apply_sysctl "net.ipv4.tcp_tw_reuse" "1"                   # 复用 TIME_WAIT
        
        echo -e "\n  ${G}✔ 配置已写入 /etc/sysctl.d/90-max-bbr.conf${N}"
        echo -e "  ${G}✔ BBR + 网络优化已生效${N}"
        ;;
    2)
        echo -e "\n  ${Y}仅启用 BBR...${N}\n"
        mkdir -p /etc/sysctl.d 2>/dev/null || true
        apply_sysctl "net.core.default_qdisc" "fq"
        apply_sysctl "net.ipv4.tcp_congestion_control" "bbr"
        echo -e "\n  ${G}✔ BBR 已启用${N}"
        ;;
    3)
        echo -e "\n  ${M}BBR 状态检查${N}"
        echo -e "  ${GR}───${N}"
        echo -e "  ${C}当前拥塞控制:${N}  ${W}$(sysctl -n net.ipv4.tcp_congestion_control 2>/dev/null)${N}"
        echo -e "  ${C}当前队列算法:${N}   ${W}$(sysctl -n net.core.default_qdisc 2>/dev/null)${N}"
        
        # 验证 BBR 是否加载
        if lsmod | grep -q tcp_bbr; then
            echo -e "  ${C}BBR 模块:${N}       ${G}已加载${N}"
        else
            echo -e "  ${C}BBR 模块:${N}       ${Y}未加载${N}"
        fi
        
        # 显示可用拥塞控制算法
        available=$(sysctl -n net.ipv4.tcp_available_congestion_control 2>/dev/null)
        echo -e "  ${C}可用算法:${N}       ${GR}$available${N}"
        
        # 检查 sysctl.d 配置
        for f in /etc/sysctl.d/*.conf /etc/sysctl.conf; do
            [ -f "$f" ] && grep -q "tcp_congestion_control\|default_qdisc" "$f" 2>/dev/null && \
                echo -e "  ${C}配置来源:${N}       ${GR}$f${N}"
        done
        ;;
    4)
        echo -e "\n  ${Y}恢复默认拥塞控制 (cubic + pfifo_fast)...${N}\n"
        apply_sysctl "net.core.default_qdisc" "pfifo_fast"
        apply_sysctl "net.ipv4.tcp_congestion_control" "cubic"
        
        # 移除其他 BBR 相关优化（恢复默认缓冲区）
        local confd="/etc/sysctl.d"
        [ ! -d "$confd" ] && confd="/etc/sysctl.d"
        local file="$confd/90-max-bbr.conf"
        if [ -f "$file" ]; then
            # 备份原配置
            cp "$file" "${file}.bak.$(date +%Y%m%d%H%M%S)" 2>/dev/null || true
            rm -f "$file"
            echo -e "  ${G}✔ 已移除 $file${N}"
        fi
        echo -e "\n  ${G}✔ 已恢复默认拥塞控制算法${N}"
        echo -e "  ${Y}⚠ 建议重启或手动检查 sysctl 配置${N}"
        ;;
    q|Q)
        echo -e "  ${GR}退出${N}"
        exit 0
        ;;
    *)
        echo -e "  ${R}无效选择${N}"
        exit 1
        ;;
esac

# 验证最终状态
echo
echo -e "  ${M}验证结果:${N}"
sysctl net.ipv4.tcp_congestion_control net.core.default_qdisc 2>/dev/null | while read -r line; do
    echo -e "  ${G}✔${N} ${GR}$line${N}"
done

echo
echo -e "${GR}👉 网络诊断: max-netstat.sh | HTTP 测试: max-httpdiag.sh | 实时 Ping: max-pingmon.sh${N}"
echo -e "${GR}👉 一键执行: bash <(curl -fsSL https://dl.unvmax.com/linux/scripts/max-tools/max-bbr.sh)${N}"