networking interface http

net.go

package net

import (
	"errors"
	"net"
	"strings"
	"time"
)

// 给定网卡名称，获取该网卡出口链接
func GetConnByName(name, network, address string) (conn net.Conn, err error) {
	intf, err := net.InterfaceByName(name)
	if err != nil {
		return nil, err
	}

	addrs, err := intf.Addrs()
	if err != nil {
		return nil, err
	}

	if len(addrs) < 2 {
		return nil, errors.New("not addrs")
	}

	addr := strings.Split(addrs[1].String(), "/")[0]

	ipAddr, err := net.ResolveTCPAddr("tcp", addr+":0")
	if err != nil {
		return
	}

	dialer := net.Dialer{
		Timeout:   time.Second * 10,
		LocalAddr: ipAddr,
		KeepAlive: time.Second * 60,
	}

	return dialer.Dial(network, address)
}

net_test.go

package net

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

// 测试出口网卡是否为选定的网卡外网IP
func TestConnByInterface(t *testing.T) {
	client := new(http.Client)
	client.Transport = &http.Transport{
		Dial: func(network, addr string) (net.Conn, error) {
			return GetConnByName("ppp0", network, addr)
		},
	}

	resp, err := client.Get("http://ip.chinaz.com/getip.aspx")
	if err != nil {
		t.Fatal(err)
	}

	data, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		t.Fatal(err)
	}

	fmt.Println(string(data))
}