如何在轉到 IP 地址中綁定 http.Client

Question

我有一台帶有多個 NIC 的客戶端機器，如何將 Go 中的 http.Client 綁定到某個 NIC 或某個 SRC IP 地址？

假設您有一些非常基本的 http 客戶端代碼，如下所示：

package main

import (
    "net/http"
)

func main() {
    webclient := &http.Client{}
    req, _ := http.NewRequest("GET", "http://www.google.com", nil)
    httpResponse, _ := webclient.Do(req)
    defer httpResponse.Body.Close()
}

有沒有辦法綁定到某個網卡或IP？

Answer 1

與此問題類似，您需要設置http.Client.Transport字段。 將其設置為net.Transport的實例允許您指定要使用的net.Dialer 。 net.Dialer然后允許您指定本地地址以建立連接。

例子：

localAddr, err := net.ResolveIPAddr("ip", "<my local address>")
if err != nil {
  panic(err)
}

// You also need to do this to make it work and not give you a 
// "mismatched local address type ip"
// This will make the ResolveIPAddr a TCPAddr without needing to 
// say what SRC port number to use.
localTCPAddr := net.TCPAddr{
    IP: localAddr.IP,
}


webclient := &http.Client{
    Transport: &http.Transport{
        Proxy: http.ProxyFromEnvironment,
        DialContext: (&net.Dialer{
            LocalAddr: &localTCPAddr,
            Timeout:   30 * time.Second,
            KeepAlive: 30 * time.Second,
            DualStack: true,
        }).DialContext,
        MaxIdleConns:          100,
        IdleConnTimeout:       90 * time.Second,
        TLSHandshakeTimeout:   10 * time.Second,
        ExpectContinueTimeout: 1 * time.Second,
    },
}

Answer 2

這是一個完整的示例，其中包含了 Tim 的答案。 我還打破了所有嵌套的部分，以便於閱讀和學習。

package main

import (
    "fmt"
    "io/ioutil"
    "net"
    "net/http"
    "time"
)

func main() {
    localAddr, err := net.ResolveIPAddr("ip", "10.128.64.219")
    if err != nil {
        panic(err)
    }

    localTCPAddr := net.TCPAddr{
        IP: localAddr.IP,
    }

    d := net.Dialer{
        LocalAddr: &localTCPAddr,
        Timeout:   30 * time.Second,
        KeepAlive: 30 * time.Second,
    }

    tr := &http.Transport{
        Proxy:               http.ProxyFromEnvironment,
        Dial:                d.Dial,
        TLSHandshakeTimeout: 10 * time.Second,
    }

    webclient := &http.Client{Transport: tr}

    // Use NewRequest so we can change the UserAgent string in the header
    req, err := http.NewRequest("GET", "http://www.google.com:80", nil)
    if err != nil {
        panic(err)
    }

    res, err := webclient.Do(req)
    if err != nil {
        panic(err)
    }

    fmt.Println("DEBUG", res)
    defer res.Body.Close()

    content, err := ioutil.ReadAll(res.Body)
    if err != nil {
        panic(err)
    }
    fmt.Printf("%s", string(content))
}