mirror of
https://github.com/netbirdio/go-netroute.git
synced 2026-05-22 17:11:07 -07:00
give up on not-reinventing the linux wheel
This commit is contained in:
Will Scott
@@ -0,0 +1,150 @@
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// Copyright 2012 Google, Inc. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the LICENSE file in the root of the source
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// tree.
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// Originally found in
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// https://github.com/google/gopacket/blob/master/routing/routing.go
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// * Route selection modified to choose most selective route
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// to break ties when route priority is insufficient.
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package netroute
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import (
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"bytes"
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"errors"
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"fmt"
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"net"
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"strings"
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)
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// Pulled from http://man7.org/linux/man-pages/man7/rtnetlink.7.html
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// See the section on RTM_NEWROUTE, specifically 'struct rtmsg'.
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type routeInfoInMemory struct {
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Family byte
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DstLen byte
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SrcLen byte
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TOS byte
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Table byte
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Protocol byte
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Scope byte
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Type byte
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Flags uint32
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}
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// rtInfo contains information on a single route.
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type rtInfo struct {
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Src, Dst *net.IPNet
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Gateway, PrefSrc net.IP
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// We currently ignore the InputIface.
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InputIface, OutputIface uint32
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Priority uint32
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}
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// routeSlice implements sort.Interface to sort routes by Priority.
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type routeSlice []*rtInfo
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func (r routeSlice) Len() int {
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return len(r)
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}
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func (r routeSlice) Less(i, j int) bool {
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return r[i].Priority < r[j].Priority
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}
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func (r routeSlice) Swap(i, j int) {
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r[i], r[j] = r[j], r[i]
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}
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type router struct {
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ifaces []net.Interface
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addrs []ipAddrs
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v4, v6 routeSlice
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}
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func (r *router) String() string {
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strs := []string{"ROUTER", "--- V4 ---"}
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for _, route := range r.v4 {
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strs = append(strs, fmt.Sprintf("%+v", *route))
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}
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strs = append(strs, "--- V6 ---")
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for _, route := range r.v6 {
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strs = append(strs, fmt.Sprintf("%+v", *route))
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}
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return strings.Join(strs, "\n")
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}
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type ipAddrs struct {
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v4, v6 net.IP
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}
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func (r *router) Route(dst net.IP) (iface *net.Interface, gateway, preferredSrc net.IP, err error) {
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return r.RouteWithSrc(nil, nil, dst)
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}
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func (r *router) RouteWithSrc(input net.HardwareAddr, src, dst net.IP) (iface *net.Interface, gateway, preferredSrc net.IP, err error) {
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var ifaceIndex int
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switch {
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case dst.To4() != nil:
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ifaceIndex, gateway, preferredSrc, err = r.route(r.v4, input, src, dst)
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case dst.To16() != nil:
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ifaceIndex, gateway, preferredSrc, err = r.route(r.v6, input, src, dst)
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default:
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err = errors.New("IP is not valid as IPv4 or IPv6")
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return
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}
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if err != nil {
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return
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}
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// Interfaces are 1-indexed, but we store them in a 0-indexed array.
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ifaceIndex--
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iface = &r.ifaces[ifaceIndex]
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if preferredSrc == nil {
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switch {
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case dst.To4() != nil:
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preferredSrc = r.addrs[ifaceIndex].v4
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case dst.To16() != nil:
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preferredSrc = r.addrs[ifaceIndex].v6
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}
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}
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return
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}
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func (r *router) route(routes routeSlice, input net.HardwareAddr, src, dst net.IP) (iface int, gateway, preferredSrc net.IP, err error) {
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var inputIndex uint32
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if input != nil {
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for i, iface := range r.ifaces {
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if bytes.Equal(input, iface.HardwareAddr) {
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// Convert from zero- to one-indexed.
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inputIndex = uint32(i + 1)
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break
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}
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}
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}
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var mostSpecificRt *rtInfo
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for _, rt := range routes {
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if rt.InputIface != 0 && rt.InputIface != inputIndex {
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continue
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}
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if src != nil && rt.Src != nil && !rt.Src.Contains(src) {
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continue
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}
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if rt.Dst != nil && !rt.Dst.Contains(dst) {
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continue
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}
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if mostSpecificRt != nil {
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candSpec, _ := rt.Dst.Mask.Size()
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if curSpec, _ := mostSpecificRt.Dst.Mask.Size(); candSpec < curSpec {
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continue
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}
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}
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mostSpecificRt = rt
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}
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if mostSpecificRt != nil {
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return int(mostSpecificRt.OutputIface), mostSpecificRt.Gateway, mostSpecificRt.PrefSrc, nil
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}
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err = fmt.Errorf("no route found for %v", dst)
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return
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}
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+2
-138
@@ -6,158 +6,22 @@
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// +build darwin dragonfly freebsd netbsd openbsd
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// This is a copy of
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// This is a BSD import for the routing structure initially found in
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// https://github.com/google/gopacket/blob/master/routing/routing.go
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// but with RIB parsing following the route format described in
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//RIB parsing follows the BSD route format described in
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// https://github.com/freebsd/freebsd/blob/master/sys/net/route.h
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package netroute
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import (
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"bytes"
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"errors"
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"fmt"
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"net"
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"sort"
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"strings"
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"syscall"
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"github.com/google/gopacket/routing"
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"golang.org/x/net/route"
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)
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// Pulled from http://man7.org/linux/man-pages/man7/rtnetlink.7.html
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// See the section on RTM_NEWROUTE, specifically 'struct rtmsg'.
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type routeInfoInMemory struct {
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Family byte
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DstLen byte
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SrcLen byte
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TOS byte
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Table byte
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Protocol byte
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Scope byte
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Type byte
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Flags uint32
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}
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// rtInfo contains information on a single route.
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type rtInfo struct {
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Src, Dst *net.IPNet
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Gateway, PrefSrc net.IP
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// We currently ignore the InputIface.
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InputIface, OutputIface uint32
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Priority uint32
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}
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// routeSlice implements sort.Interface to sort routes by Priority.
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type routeSlice []*rtInfo
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func (r routeSlice) Len() int {
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return len(r)
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}
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func (r routeSlice) Less(i, j int) bool {
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return r[i].Priority < r[j].Priority
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}
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func (r routeSlice) Swap(i, j int) {
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r[i], r[j] = r[j], r[i]
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}
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type router struct {
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ifaces []net.Interface
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addrs []ipAddrs
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v4, v6 routeSlice
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}
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func (r *router) String() string {
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strs := []string{"ROUTER", "--- V4 ---"}
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for _, route := range r.v4 {
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strs = append(strs, fmt.Sprintf("%+v", *route))
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}
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strs = append(strs, "--- V6 ---")
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for _, route := range r.v6 {
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strs = append(strs, fmt.Sprintf("%+v", *route))
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}
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return strings.Join(strs, "\n")
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}
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type ipAddrs struct {
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v4, v6 net.IP
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}
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func (r *router) Route(dst net.IP) (iface *net.Interface, gateway, preferredSrc net.IP, err error) {
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return r.RouteWithSrc(nil, nil, dst)
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}
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func (r *router) RouteWithSrc(input net.HardwareAddr, src, dst net.IP) (iface *net.Interface, gateway, preferredSrc net.IP, err error) {
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var ifaceIndex int
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switch {
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case dst.To4() != nil:
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ifaceIndex, gateway, preferredSrc, err = r.route(r.v4, input, src, dst)
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case dst.To16() != nil:
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ifaceIndex, gateway, preferredSrc, err = r.route(r.v6, input, src, dst)
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default:
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err = errors.New("IP is not valid as IPv4 or IPv6")
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return
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}
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if err != nil {
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return
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}
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// Interfaces are 1-indexed, but we store them in a 0-indexed array.
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ifaceIndex--
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iface = &r.ifaces[ifaceIndex]
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if preferredSrc == nil {
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switch {
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case dst.To4() != nil:
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preferredSrc = r.addrs[ifaceIndex].v4
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case dst.To16() != nil:
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preferredSrc = r.addrs[ifaceIndex].v6
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}
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}
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return
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}
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func (r *router) route(routes routeSlice, input net.HardwareAddr, src, dst net.IP) (iface int, gateway, preferredSrc net.IP, err error) {
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var inputIndex uint32
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if input != nil {
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for i, iface := range r.ifaces {
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if bytes.Equal(input, iface.HardwareAddr) {
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// Convert from zero- to one-indexed.
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inputIndex = uint32(i + 1)
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break
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}
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}
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}
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var mostSpecificRt *rtInfo
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for _, rt := range routes {
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if rt.InputIface != 0 && rt.InputIface != inputIndex {
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continue
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}
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if src != nil && rt.Src != nil && !rt.Src.Contains(src) {
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continue
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}
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if rt.Dst != nil && !rt.Dst.Contains(dst) {
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continue
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}
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if mostSpecificRt != nil {
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candSpec, _ := rt.Dst.Mask.Size()
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if curSpec, _ := mostSpecificRt.Dst.Mask.Size(); candSpec < curSpec {
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continue
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}
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}
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mostSpecificRt = rt
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}
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if mostSpecificRt != nil {
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return int(mostSpecificRt.OutputIface), mostSpecificRt.Gateway, mostSpecificRt.PrefSrc, nil
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}
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err = fmt.Errorf("no route found for %v", dst)
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return
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}
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// Begin modifications
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func toIPAddr(a route.Addr) (net.IP, error) {
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switch t := a.(type) {
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case *route.Inet4Addr:
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+98
-18
@@ -1,33 +1,113 @@
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// Copyright 2012 Google, Inc. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the LICENSE file in the root of the source
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// tree.
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// +build linux
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// Generate a local routing table structure following the code at
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// https://github.com/google/gopacket/blob/master/routing/routing.go
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package netroute
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import (
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"fmt"
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"net"
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"sort"
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"syscall"
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"unsafe"
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"github.com/google/gopacket/routing"
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)
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type router struct {
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routing.Router
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}
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func (r *router) Route(dst net.IP) (iface *net.Interface, gateway, preferredSrc net.IP, err error) {
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return r.RouteWithSrc(nil, nil, dst)
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}
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func (r *router) RouteWithSrc(input net.HardwareAddr, src, dst net.IP) (iface *net.Interface, gateway, preferredSrc net.IP, err error) {
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iface, gateway, preferredSrc, err = r.Router.RouteWithSrc(input, src, dst)
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if dst.Equal(preferredSrc) {
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gateway = nil
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}
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return iface, gateway, preferredSrc, err
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}
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func New() (routing.Router, error) {
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r, err := routing.New()
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rtr := &router{}
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tab, err := syscall.NetlinkRIB(syscall.RTM_GETROUTE, syscall.AF_UNSPEC)
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if err != nil {
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return nil, err
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}
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return &router{r}, nil
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msgs, err := syscall.ParseNetlinkMessage(tab)
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if err != nil {
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return nil, err
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}
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loop:
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for _, m := range msgs {
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switch m.Header.Type {
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case syscall.NLMSG_DONE:
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break loop
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case syscall.RTM_NEWROUTE:
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rt := (*routeInfoInMemory)(unsafe.Pointer(&m.Data[0]))
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routeInfo := rtInfo{}
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attrs, err := syscall.ParseNetlinkRouteAttr(&m)
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if err != nil {
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return nil, err
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}
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switch rt.Family {
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case syscall.AF_INET:
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rtr.v4 = append(rtr.v4, &routeInfo)
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case syscall.AF_INET6:
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rtr.v6 = append(rtr.v6, &routeInfo)
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default:
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continue loop
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}
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for _, attr := range attrs {
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switch attr.Attr.Type {
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case syscall.RTA_DST:
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routeInfo.Dst = &net.IPNet{
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IP: net.IP(attr.Value),
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Mask: net.CIDRMask(int(rt.DstLen), len(attr.Value)*8),
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}
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case syscall.RTA_SRC:
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routeInfo.Src = &net.IPNet{
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IP: net.IP(attr.Value),
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Mask: net.CIDRMask(int(rt.SrcLen), len(attr.Value)*8),
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}
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case syscall.RTA_GATEWAY:
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routeInfo.Gateway = net.IP(attr.Value)
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case syscall.RTA_PREFSRC:
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routeInfo.PrefSrc = net.IP(attr.Value)
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case syscall.RTA_IIF:
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routeInfo.InputIface = *(*uint32)(unsafe.Pointer(&attr.Value[0]))
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case syscall.RTA_OIF:
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routeInfo.OutputIface = *(*uint32)(unsafe.Pointer(&attr.Value[0]))
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case syscall.RTA_PRIORITY:
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routeInfo.Priority = *(*uint32)(unsafe.Pointer(&attr.Value[0]))
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}
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}
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}
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}
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sort.Sort(rtr.v4)
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sort.Sort(rtr.v6)
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ifaces, err := net.Interfaces()
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if err != nil {
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return nil, err
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}
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for i, iface := range ifaces {
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if i != iface.Index-1 {
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return nil, fmt.Errorf("out of order iface %d = %v", i, iface)
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}
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rtr.ifaces = append(rtr.ifaces, iface)
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var addrs ipAddrs
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ifaceAddrs, err := iface.Addrs()
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if err != nil {
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return nil, err
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}
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for _, addr := range ifaceAddrs {
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if inet, ok := addr.(*net.IPNet); ok {
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// Go has a nasty habit of giving you IPv4s as ::ffff:1.2.3.4 instead of 1.2.3.4.
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// We want to use mapped v4 addresses as v4 preferred addresses, never as v6
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// preferred addresses.
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if v4 := inet.IP.To4(); v4 != nil {
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if addrs.v4 == nil {
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addrs.v4 = v4
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}
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} else if addrs.v6 == nil {
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addrs.v6 = inet.IP
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}
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}
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}
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rtr.addrs = append(rtr.addrs, addrs)
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}
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return rtr, nil
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}
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+1
-5
@@ -1,7 +1,6 @@
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package netroute
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import (
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"fmt"
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"net"
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"strings"
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"testing"
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@@ -31,20 +30,17 @@ func TestRoute(t *testing.T) {
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if strings.HasPrefix(addr.Network(), "ip") {
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_, ipn, _ := net.ParseCIDR(addr.String())
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if ipn.IP.To4() == nil && !ipn.IP.IsInterfaceLocalMulticast() && !ipn.IP.IsLinkLocalUnicast() && !ipn.IP.IsLinkLocalMulticast() {
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fmt.Printf("See IPv6 Interface: %v\n", addr)
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hasV6 = true
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break
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}
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}
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}
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iface, gw, src, err := r.Route(localAddr)
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_, gw, src, err := r.Route(localAddr)
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if err != nil {
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t.Fatal(err)
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}
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if gw != nil || !src.Equal(localAddr) {
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fmt.Printf("iface for localhost is %v\n", iface)
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fmt.Printf("when routing to %v, saw %v\n", localAddr, src)
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t.Fatalf("Did not expect gateway to localhost: %v", gw)
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}
|
||||
|
||||
|
||||
Reference in New Issue
Block a user