Go 本机私有IPv4地址获取代码

通过以下代码获取本机私有IPv4地址

方一：

package main

import (
    "net"
    "fmt"
)

func main(){
    addrs,_ := GetPrivateIPv4()
    for _,addr :=range addrs {
        println(addr.String())
    }

}

// privateBlocks contains non-forwardable address blocks which are used
// for private networks. RFC 6890 provides an overview of special
// address blocks.
var privateBlocks = []*net.IPNet{
    parseCIDR("10.0.0.0/8"),     // RFC 1918 IPv4 private network address
    parseCIDR("100.64.0.0/10"),  // RFC 6598 IPv4 shared address space
    parseCIDR("127.0.0.0/8"),    // RFC 1122 IPv4 loopback address
    parseCIDR("169.254.0.0/16"), // RFC 3927 IPv4 link local address
    parseCIDR("172.16.0.0/12"),  // RFC 1918 IPv4 private network address
    parseCIDR("192.0.0.0/24"),   // RFC 6890 IPv4 IANA address
    parseCIDR("192.0.2.0/24"),   // RFC 5737 IPv4 documentation address
    parseCIDR("192.168.0.0/16"), // RFC 1918 IPv4 private network address
    parseCIDR("::1/128"),        // RFC 1884 IPv6 loopback address
    parseCIDR("fe80::/10"),      // RFC 4291 IPv6 link local addresses
    parseCIDR("fc00::/7"),       // RFC 4193 IPv6 unique local addresses
    parseCIDR("fec0::/10"),      // RFC 1884 IPv6 site-local addresses
    parseCIDR("2001:db8::/32"),  // RFC 3849 IPv6 documentation address
}


func parseCIDR(s string) *net.IPNet {
    _, block, err := net.ParseCIDR(s)
    if err != nil {
        panic(fmt.Sprintf("Bad CIDR %s: %s", s, err))
    }
    return block
}

func GetPrivateIPv4() ([]*net.IPAddr, error) {
    addresses, err := activeInterfaceAddresses()
    if err != nil {
        return nil, fmt.Errorf("Failed to get interface addresses: %v", err)
    }

    var addrs []*net.IPAddr
    for _, rawAddr := range addresses {
        var ip net.IP
        switch addr := rawAddr.(type) {
        case *net.IPAddr:
            ip = addr.IP
        case *net.IPNet:
            ip = addr.IP
        default:
            continue
        }
        if ip.To4() == nil {
            continue
        }

        if !isPrivate(ip) {
            continue
        }
        addrs = append(addrs, &net.IPAddr{IP: ip})
    }
    return addrs, nil
}

// Returns addresses from interfaces that is up
func activeInterfaceAddresses() ([]net.Addr, error) {
    var upAddrs []net.Addr
    var loAddrs []net.Addr

    interfaces, err := net.Interfaces()
    if err != nil {
        return nil, fmt.Errorf("Failed to get interfaces: %v", err)
    }

    for _, iface := range interfaces {
        // Require interface to be up
        if iface.Flags&net.FlagUp == 0 {
            continue
        }

        addresses, err := iface.Addrs()
        if err != nil {
            return nil, fmt.Errorf("Failed to get interface addresses: %v", err)
        }

        if iface.Flags&net.FlagLoopback != 0 {
            loAddrs = append(loAddrs, addresses...)
            continue
        }

        upAddrs = append(upAddrs, addresses...)
    }

    if len(upAddrs) == 0 {
        return loAddrs, nil
    }

    return upAddrs, nil
}

func isPrivate(ip net.IP) bool {
    for _, priv := range privateBlocks {
        if priv.Contains(ip) {
            return true
        }
    }
    return false
}

方二：

func GetNoLoopbackAddr() string {
    ifaces, err := net.Interfaces()
    if err != nil {
        panic(err)
    }
    for _, iface := range ifaces {
        if (iface.Flags&net.FlagUp == net.FlagUp) && (iface.Flags&net.FlagLoopback != net.FlagLoopback) && (iface.Flags&net.FlagPointToPoint != net.FlagPointToPoint) {
            addrs, err := iface.Addrs()
            if err != nil {
                panic(err)
            }
            for _, addr := range addrs {

                if ipAddr, ok := addr.(*net.IPNet); ok {
                    ipV4 := ipAddr.IP.To4()
                    if ipV4 != nil {
                        return ipV4.String()
                    }
                }

                if ipAddr, ok := addr.(*net.IPAddr); ok {
                    ipV4 := ipAddr.IP.To4()
                    if ipV4 != nil {
                        return ipV4.String()
                    }
                }
            }
        }
    }
    return ""
}