Golang 连接 Kerberos 服务器：完整指南及代码示例

要在 Go 中连接 Kerberos 服务器，您需要使用 GSS-API（通用安全服务应用程序接口）库。以下是一个简单的示例代码，它使用 GSS-API 库连接 Kerberos 服务器：

package main

import (
    "fmt"
    "golang.org/x/net/ipv4"
    "gopkg.in/jcmturner/gokrb5.v7/client"
    "gopkg.in/jcmturner/gokrb5.v7/config"
    "gopkg.in/jcmturner/gokrb5.v7/credentials"
    "gopkg.in/jcmturner/gokrb5.v7/keytab"
    "gopkg.in/jcmturner/gokrb5.v7/types"
    "time"
)

func main() {
    // Load the Kerberos configuration file.
    cfg, _ := config.Load("/etc/krb5.conf")

    // Load the keytab file.
    kt, _ := keytab.Load("/etc/krb5.keytab")

    // Create a new client using the configuration and keytab.
    cl := client.NewWithKeytab("user@REALM.COM", "REALM.COM", kt)

    // Get a TGT (ticket-granting ticket) from the Kerberos server.
    err := cl.Login()
    if err != nil {
        fmt.Println("Failed to authenticate: ", err)
        return
    }

    // Use the TGT to get a service ticket for the desired service.
    spn := types.SPNEGOHTTP("example.com")
    tkt, err := cl.GetServiceTicket(spn)
    if err != nil {
        fmt.Println("Failed to get service ticket: ", err)
        return
    }

    // Connect to the service using the service ticket.
    conn, err := ipv4.Dial("tcp", "example.com:80")
    if err != nil {
        fmt.Println("Failed to connect to service: ", err)
        return
    }

    // Use the service ticket to authenticate the connection.
    err = conn.SetControlMessage(ipv4.FlagDst, true)
    if err != nil {
        fmt.Println("Failed to set control message: ", err)
        return
    }

    err = conn.SetTOS(0)
    if err != nil {
        fmt.Println("Failed to set TOS: ", err)
        return
    }

    err = conn.SetTTL(255)
    if err != nil {
        fmt.Println("Failed to set TTL: ", err)
        return
    }

    err = conn.SetSockOpt(ipv4.FlagTTL, 255)
    if err != nil {
        fmt.Println("Failed to set sockopt: ", err)
        return
    }

    err = conn.SetKeepAlive(true)
    if err != nil {
        fmt.Println("Failed to set keepalive: ", err)
        return
    }

    err = conn.SetKeepAlivePeriod(30 * time.Second)
    if err != nil {
        fmt.Println("Failed to set keepalive period: ", err)
        return
    }

    err = conn.SetDeadline(time.Now().Add(30 * time.Second))
    if err != nil {
        fmt.Println("Failed to set deadline: ", err)
        return
    }

    err = conn.Authenticate(tkt)
    if err != nil {
        fmt.Println("Failed to authenticate connection: ", err)
        return
    }

    // Use the connection to communicate with the service.
    _, err = conn.Write([]byte("GET / HTTP/1.0\r\n\r\n"))
    if err != nil {
        fmt.Println("Failed to write to connection: ", err)
        return
    }

    // ...

    conn.Close()
}

在上面的代码中，我们首先加载 Kerberos 配置文件和 keytab 文件，然后创建一个新的客户端对象。我们使用客户端对象来获取 TGT（票据授予票据）和服务票据。然后，我们使用服务票据来连接服务并进行身份验证。一旦连接完成，我们可以使用连接与服务进行通信。