feat: implement VPN platform management and real protocol services

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Logan.Li committed 2026-07-22 21:49:13 +08:00
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// Package service 提供协议实现共用的运行时工具函数
package service
import (
"bytes"
"crypto/rand"
"encoding/base64"
"encoding/json"
"fmt"
"net"
"os"
"os/exec"
"path/filepath"
"strconv"
"strings"
"syscall"
"time"
"vpn-platform/backend/internal/core"
"vpn-platform/backend/internal/model"
"vpn-platform/backend/internal/store"
)
// BaseDir 实例配置与运行时根目录(可通过 VPN_DATA_DIR 覆盖)
func BaseDir() string {
if v := os.Getenv("VPN_DATA_DIR"); v != "" {
return v
}
exe, _ := os.Executable()
if exe != "" {
return filepath.Join(filepath.Dir(exe), "data")
}
return "data"
}
// InstanceDir 专线实例目录
func InstanceDir(t *model.Tunnel) string {
return filepath.Join(BaseDir(), "instances", fmt.Sprintf("%d-%s", t.ID, t.Protocol))
}
// LookBin 检测系统依赖二进制
func LookBin(names ...string) (string, bool) {
for _, n := range names {
if p, err := exec.LookPath(n); err == nil {
return p, true
}
}
return "", false
}
// Run 执行命令并返回输出
func Run(name string, args ...string) (string, error) {
cmd := exec.Command(name, args...)
var out, errOut bytes.Buffer
cmd.Stdout = &out
cmd.Stderr = &errOut
if err := cmd.Run(); err != nil {
return out.String(), fmt.Errorf("%s %s 执行失败: %v %s", name, strings.Join(args, " "), err, errOut.String())
}
return out.String(), nil
}
// RequireRoot rejects service operations that need kernel networking privileges.
// Starting the web process as an unprivileged account must never be reported as
// a running VPN service merely because configuration generation succeeded.
func RequireRoot(component string) error {
if os.Geteuid() != 0 {
return fmt.Errorf("无法启动 %s:需要 root 权限以管理内核网络、IPSec SA 和防火墙规则", component)
}
return nil
}
// RequireIPv4Forwarding verifies the kernel prerequisite for forwarding traffic
// between a VPN address pool and the LAN/Internet.
func RequireIPv4Forwarding(component string) error {
sysctl, ok := LookBin("sysctl")
if !ok {
return fmt.Errorf("无法启动 %s:未检测到 sysctl,无法确认 net.ipv4.ip_forward", component)
}
out, err := Run(sysctl, "-n", "net.ipv4.ip_forward")
if err != nil || strings.TrimSpace(out) != "1" {
return fmt.Errorf("无法启动 %s:请先执行 sysctl -w net.ipv4.ip_forward=1", component)
}
return nil
}
// RequireUDPPortAvailable checks a port before handing it to a daemon. This is
// deliberately a real bind check instead of parsing process output, so it also
// catches listeners started outside this platform.
func RequireUDPPortAvailable(port int, component string) error {
conn, err := net.ListenUDP("udp4", &net.UDPAddr{Port: port})
if err != nil {
return fmt.Errorf("无法启动 %s:UDP %d 已被其他服务占用: %w", component, port, err)
}
return conn.Close()
}
// DefaultRouteInterface returns the interface used for IPv4 Internet egress.
// It is used only when a VPN configuration does not explicitly set one.
func DefaultRouteInterface() (string, error) {
ip, ok := LookBin("ip")
if !ok {
return "", fmt.Errorf("未检测到 iproute2 的 ip 命令,无法确定 NAT 出口接口")
}
out, err := Run(ip, "-4", "route", "show", "default")
if err != nil {
return "", err
}
fields := strings.Fields(out)
for i := 0; i+1 < len(fields); i++ {
if fields[i] == "dev" {
return fields[i+1], nil
}
}
return "", fmt.Errorf("未找到 IPv4 默认路由,无法确定 NAT 出口接口")
}
// StartDaemon 以守护方式启动进程并记录 PID
func StartDaemon(t *model.Tunnel, name string, args ...string) error {
if err := os.MkdirAll(InstanceDir(t), 0o700); err != nil {
return err
}
logFile, err := os.OpenFile(filepath.Join(InstanceDir(t), "instance.log"), os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0o600)
if err != nil {
return err
}
cmd := exec.Command(name, args...)
cmd.Stdout = logFile
cmd.Stderr = logFile
cmd.Dir = InstanceDir(t)
if err := cmd.Start(); err != nil {
logFile.Close()
return err
}
pid := cmd.Process.Pid
_ = os.WriteFile(PidFile(t), []byte(strconv.Itoa(pid)), 0o600)
go func() { _ = cmd.Wait(); logFile.Close() }()
return nil
}
// PidFile 实例 PID 文件
func PidFile(t *model.Tunnel) string {
return filepath.Join(InstanceDir(t), "instance.pid")
}
// ReadPid 读取实例 PID 并校验存活
func ReadPid(t *model.Tunnel) (int, bool) {
raw, err := os.ReadFile(PidFile(t))
if err != nil {
return 0, false
}
pid, err := strconv.Atoi(strings.TrimSpace(string(raw)))
if err != nil || pid <= 0 {
return 0, false
}
proc, err := os.FindProcess(pid)
if err != nil {
return 0, false
}
// signal 0 检测进程存活
if err := proc.Signal(syscall.Signal(0)); err != nil {
return pid, false
}
return pid, true
}
// KillPid 停止实例进程
func KillPid(t *model.Tunnel) error {
pid, alive := ReadPid(t)
if !alive {
return nil
}
proc, err := os.FindProcess(pid)
if err != nil {
return nil
}
_ = proc.Kill()
_, _ = proc.Wait()
_ = os.Remove(PidFile(t))
return nil
}
// WriteConfig 写入实例配置文件(0600 权限)
func WriteConfig(t *model.Tunnel, name, content string) (string, error) {
if err := os.MkdirAll(InstanceDir(t), 0o700); err != nil {
return "", err
}
p := filepath.Join(InstanceDir(t), name)
if err := os.WriteFile(p, []byte(content), 0o600); err != nil {
return "", err
}
return p, nil
}
// RandomSecret 生成适合配置文件与 API 凭据使用的不可预测随机值。
func RandomSecret(bytesLen int) (string, error) {
raw := make([]byte, bytesLen)
if _, err := rand.Read(raw); err != nil {
return "", err
}
return base64.RawURLEncoding.EncodeToString(raw), nil
}
// RemoveInstance 清理隧道的专属配置、日志与 PID 文件。
func RemoveInstance(t *model.Tunnel) error {
return os.RemoveAll(InstanceDir(t))
}
// Str / StrOr / Num / Bool 从配置 map 中安全取值
func Str(cfg map[string]interface{}, key string) string {
if v, ok := cfg[key]; ok {
if s, ok := v.(string); ok {
return s
}
}
return ""
}
func StrOr(cfg map[string]interface{}, key, def string) string {
if s := Str(cfg, key); s != "" {
return s
}
return def
}
func Num(cfg map[string]interface{}, key string, def float64) float64 {
if v, ok := cfg[key]; ok {
switch n := v.(type) {
case float64:
return n
case int:
return float64(n)
case string:
if f, err := strconv.ParseFloat(n, 64); err == nil {
return f
}
}
}
return def
}
func Bool(cfg map[string]interface{}, key string, def bool) bool {
if v, ok := cfg[key]; ok {
if b, ok := v.(bool); ok {
return b
}
}
return def
}
// MustValidate 公共校验:配置必须是合法 JSON 对象
func MustValidate(cfg map[string]interface{}, required ...string) error {
for _, k := range required {
if Str(cfg, k) == "" && Num(cfg, k, 0) == 0 {
return fmt.Errorf("缺少必填参数: %s", k)
}
}
return nil
}
// ConfigJSON 序列化配置
func ConfigJSON(cfg map[string]interface{}) string {
raw, _ := json.Marshal(cfg)
return string(raw)
}
// NowStatus 构造状态对象
func NowStatus(running bool, state, detail string) core.Status {
return core.Status{Running: running, State: state, Detail: detail, UpdatedAt: time.Now().Unix()}
}
// MergeSecrets 从 cfg 中提取敏感字段,返回 (脱敏后的公开配置, 敏感配置)
func MergeSecrets(cfg map[string]interface{}, secretKeys ...string) (public map[string]interface{}, secrets map[string]interface{}) {
public = map[string]interface{}{}
secrets = map[string]interface{}{}
for k, v := range cfg {
isSecret := false
for _, sk := range secretKeys {
if k == sk {
isSecret = true
break
}
}
if isSecret {
secrets[k] = v
} else {
public[k] = v
}
}
return
}
// SaveTunnelConfig 将公开配置与加密密钥写回数据库
func SaveTunnelConfig(t *model.Tunnel, public, secrets map[string]interface{}) error {
t.Config = ConfigJSON(public)
if len(secrets) > 0 {
raw, _ := json.Marshal(secrets)
enc, err := store.EncryptSecret(string(raw))
if err != nil {
return err
}
t.Secrets = enc
}
return store.DB.Save(t).Error
}