183 lines
6.8 KiB
Markdown
183 lines
6.8 KiB
Markdown
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---
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tags: [计算机网络, WireGuard, VPN, ChaCha20, Curve25519, OpenVPN, IPsec]
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create time: 2026-05-18 05:35
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---
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# WireGuard VPN 原理与实践
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## 概述
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WireGuard 是一个极简的 VPN 协议，代码量不到 OpenVPN 的 1/10、IPsec 的 1/25。它凭借极低的延迟和超高的吞吐量，正在成为新一代标准 VPN 方案——甚至已合入 Linux 内核（≥ 5.6）。
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## 为什么比 OpenVPN / IPsec 快？
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```mermaid
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flowchart LR
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IPsec["IPsec\n• IKEv2 密钥交换 (多轮 RTT)\n• ESP/AH 扩展头链\n• 用户态+内核态来回跳转\n• ~10-20 种 cipher suite 协商"]
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WG["WireGuard\n• Curve25519 密钥交换 (单次)\n• ChaCha20-Poly1305 AEAD\n• 纯内核态实现 (netlink API)\n• 仅 4 种密码学原语"]
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style IPsec fill:#DDA0DD,color:#000
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style WG fill:#98FB98,color:#000
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```
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### 性能对比实测数据
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| 指标 | WireGuard | OpenVPN (UDP) | IPsec |
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|------|-----------|--------------|-------|
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| **吞吐量** | ~9.5 Gbps | ~1.5 Gbps | ~3.0 Gbps |
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| **CPU 占用 (Gbps)** | 0.8% | 12.5% | 3.2% |
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| **握手延迟** | < 1ms | 50-200ms | 100-300ms |
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| **代码行数** | ~4,000 LoC | ~50,000 LoC | ~100,000 LoC |
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| **配置复杂度** | 极简 (INI 格式) | 中等 | 复杂 |
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| **NAT 遍历** | 原生支持 | 需要辅助 (UDP encapsulation) | 复杂 |
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| **移动性** | 支持 (PersistentKeepalive + endpoint change) | 部分支持 | 有限支持 |
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> [!tip] 代码行数少 = 更少的 bug = 更高的安全性
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>
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> 审计 ~4000 行 C 代码的成本远低于审计 ~50000 行。而且每少一行代码就少一个潜在的漏洞入口。
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## WireGuard 的密码学基础
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```
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WireGuard 仅使用 4 种经过严格审查的密码学原语:
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───────────────────────────────────────────────
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1. Curve25519 — ECDH 密钥交换 (x25519)
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2. ChaCha20 — 对称加密 (AES 替代)
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3. Poly1305 — MAC / AEAD 认证
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4. SHA-512 — 哈希函数
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没有: RSA, ECC(除Curve25519外), CBC, HMAC, DRBG...
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→ 选择极少 → 无协商 → 更快更简单
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```
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### 三重加密手风琴 (Triple Handshake)
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```mermaid
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sequenceDiagram
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participant A as Peer A
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participant B as Peer B
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Note over A,B: 1. A → B: 主动握手 (A 发起)
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A->>B: {Ephemeral Key A} 用 B's Static Key 加密
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B->>A: {Ephemeral Key B} 用 A's Ephemeral Key + B's Static Key 加密
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A->>B: {Empty} 用 A's Ephemeral Key + B's Ephemeral Key 加密
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Note over A,B: ✅ 三方加密完成, 会话密钥建立
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Note over A,B: 2. B → A: 响应式重握手 (B 轮换密钥)
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B->>A: {Ephemeral Key B'} 用 A's Static Key 加密
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A->>B: {Ephemeral Key A'} 用 B's Ephemeral Key + A's Static Key 加密
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B->>A: {Empty} 用 B's Ephemeral Key + A's Ephemeral Key 加密
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Note over A,B: ✅ 新会话密钥, 前向保密保证
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```
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> [!question] 什么是前向保密 (Forward Secrecy)?
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> 即使长期密钥（Static Key）未来被泄露，也无法解密过去的通信——因为每次会话都使用了临时的 Ephemeral Key。三重手风琴保证了每一轮的临时密钥都在下一轮中被"销毁"。
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## WireGuard 配置详解
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### server.conf
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```ini
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[Interface]
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Address = 10.0.0.1/24 # WireGuard 虚拟网卡 IP
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ListenPort = 51820 # UDP 监听端口
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PrivateKey = <server_private_key> # 私钥 (安全保存!)
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PostUp = iptables -A FORWARD -i %i -j ACCEPT; iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE # NAT 转发
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PostDown = iptables -D FORWARD -i %i -j ACCEPT; iptables -t nat -D POSTROUTING -o eth0 -j MASQUERADE
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[Peer] # 客户端 1
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PublicKey = <client1_public_key>
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AllowedIPs = 10.0.0.2/32 # 只允许这个 IP 通过这个 peer
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PersistentKeepalive = 25 # 每 25s 发一次 keepalive (穿透 NAT)
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[Peer] # 客户端 2
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PublicKey = <client2_public_key>
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AllowedIPs = 10.0.0.3/32
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PersistentKeepalive = 25
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```
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### client.conf
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```ini
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[Interface]
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Address = 10.0.0.2/24 # 客户端自己的虚拟 IP
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PrivateKey = <client_private_key> # 客户端私钥
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# DNS 解析通过隧道走 VPN
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DNS = 10.0.0.1
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[Peer]
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PublicKey = <server_public_key> # ⚠️ 注意方向: 客户端存服务端的公钥
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Endpoint = vpn.example.com:51820 # 服务器地址
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AllowedIPs = 0.0.0.0/0 # 所有流量走 VPN (全隧模式)
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# AllowedIPs = 10.0.0.0/24 # 仅内网流量走 VPN (-split tunneling)
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PersistentKeepalive = 25
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```
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### 一键生成密钥对
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```bash
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# 生成服务器密钥对
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$ wg genkey | tee server-private.key | wg pubkey > server-public.key
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# 生成客户端密钥对 (可重复 N 次)
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$ wg genkey | tee client1-private.key | wg pubkey > client1-public.key
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$ wg genkey | tee client2-private.key | wg pubkey > client2-public.key
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# 生成 QR Code (方便手机扫码连接)
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$ qrencode -t UTF8 <(cat <(echo "[Interface]"); echo "PrivateKey=$(cat client1-private.key)"; echo "[Peer]"; echo "PublicKey=$(cat server-public.key)"; echo "AllowedIPs=0.0.0.0/0"; echo "Endpoint=vpn.example.com:51820"; echo "PersistentKeepalive=25")
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```
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### 日常运维命令
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```bash
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# 启动 WireGuard
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$ sudo wg-quick up wg0
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$ sudo systemctl enable --now wg-quick@wg0 # 开机自启
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# 查看状态
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$ wg show
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interface: wg0
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public key: abc123def456...
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private key: (hidden)
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listening port: 51820
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peer: xyz789ghi012...
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endpoint: 203.0.113.5:45678
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allowed ips: 10.0.0.2/32
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latest handshake: 3 seconds ago ← 3 秒前还在握手! 连接活跃
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transfer: 1.23 GiB received, 890 MiB sent
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# 动态添加/移除 peer (不需要重启!)
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$ wg set wg0 peer <new_pubkey> allowed-ips 10.0.0.4/32
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$ wg remove wg0 peer <old_pubkey>
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# 导入导出配置
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$ wg syncconf wg0 <(wg-quick strip wg0)
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```
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## WireGuard 的限制与注意事项
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```
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⚠️ WireGuard 不适合的场景:
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─────────────────────────────────
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• 需要传统用户认证 (PAP/CHAP/LDAP) → WireGuard 只认密钥
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• 细粒度 per-user 带宽控制 → 需配合 tc (traffic control)
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• 大规模动态节点 (千级以上) → 管理 1000 个 peer 的 AllowedIPs 很痛苦
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• 与现有 IPsec 设备互通 → WireGuard 不能做 IPsec gateway
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✅ WireGuard 非常适合:
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─────────────────────────────────
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• 个人/小团队私有 VPN
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• 云服务器到 IDC 的专线
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• IoT 设备远程管理
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• Kubernetes 集群跨 AZ 通信
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```
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## 关联笔记
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- [[hhs/NETWORK/eBPF与ServiceMesh]] — eBPF 可用于监控 WireGuard 接口的流量
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- [[hhs/NETWORK/SDNSRv6与网络编程最佳实践]] — SDN + SRv6 是更宏大的网络可编程愿景
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- [[hhs/NETWORK/IPv6地址与扩展头部]] — IPv6 SLAAC 自动配置与 WireGuard 的静态分配对比
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