Merge pull request #95328 from aojea/conntrack_invalid

add ipv6 support to the image issue-74839
This commit is contained in:
Kubernetes Prow Robot 2020-10-22 22:16:16 -07:00 committed by GitHub
commit 82cc713b13
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GPG Key ID: 4AEE18F83AFDEB23
6 changed files with 174 additions and 34 deletions

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@ -1,4 +1,4 @@
load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library", "go_test")
go_library(
name = "go_default_library",
@ -29,3 +29,9 @@ filegroup(
tags = ["automanaged"],
visibility = ["//visibility:public"],
)
go_test(
name = "go_default_test",
srcs = ["tcp_test.go"],
embed = [":go_default_library"],
)

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@ -1,2 +1,3 @@
approvers:
- anfernee
- aojea

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@ -1 +1 @@
1.1
1.2

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@ -17,20 +17,33 @@ limitations under the License.
package main
import (
"fmt"
"log"
"net"
"os"
"strings"
"time"
)
// TCP port to listen
const port = 9000
func main() {
ip := getIP().String()
log.Printf("external ip: %v", ip)
ips := getIPs()
if len(ips) == 0 {
panic("No valid IP found")
}
go probe(ip)
// listen TCP packets to inject the out of order TCP packets
for _, ip := range ips {
log.Printf("external ip: %v", ip.String())
go probe(ip.String())
}
log.Printf("listen on %v:9000", "0.0.0.0")
log.Printf("listen on %v:%d", "0.0.0.0", port)
listener, err := net.Listen("tcp", "0.0.0.0:9000")
// open a server listening to establish the TCP connections
listener, err := net.Listen("tcp", fmt.Sprintf("0.0.0.0:%d", port))
if err != nil {
panic(err)
}
@ -42,6 +55,7 @@ func main() {
}
go func(conn net.Conn) {
// Close the connection after 10 secs
time.Sleep(10 * time.Second)
conn.Close()
}(conn)
@ -51,12 +65,12 @@ func main() {
func probe(ip string) {
log.Printf("probing %v", ip)
ipAddr, err := net.ResolveIPAddr("ip4:tcp", ip)
ipAddr, err := net.ResolveIPAddr("ip:tcp", ip)
if err != nil {
panic(err)
}
conn, err := net.ListenIP("ip4:tcp", ipAddr)
conn, err := net.ListenIP("ip:tcp", ipAddr)
if err != nil {
panic(err)
}
@ -89,7 +103,7 @@ func probe(ip string) {
continue
}
if pkt.Flags&RST != 0 {
panic("RST received")
log.Println("ERROR: RST received")
}
if pkt.Flags&ACK != 0 {
if seq, ok := pending[addr.String()]; ok {
@ -111,20 +125,26 @@ func probe(ip string) {
_, err := conn.WriteTo(badPkt.encode(localIP, remoteIP, data[:]), addr)
if err != nil {
log.Printf("conn.WriteTo() error: %v", err)
} else {
log.Println("boom packet injected")
}
}
}
}
}
func getIP() net.IP {
conn, err := net.Dial("udp", "8.8.8.8:53")
if err != nil {
log.Fatal(err)
// getIPs gets the IPs from the downward API
// we don't have to validate the IPs because
// they are validated previously by kubernetes/CNI
func getIPs() []net.IP {
var ips []net.IP
podIP, podIPs := os.Getenv("POD_IP"), os.Getenv("POD_IPS")
if podIPs != "" {
for _, ip := range strings.Split(podIPs, ",") {
ips = append(ips, net.ParseIP(ip))
}
} else if podIP != "" {
ips = append(ips, net.ParseIP(podIP))
}
defer conn.Close()
localAddr := conn.LocalAddr().(*net.UDPAddr)
return localAddr.IP
return ips
}

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@ -31,6 +31,10 @@ const (
)
const (
// Control Bits. 6 bits.
// 00 01 02 03 04 05
// U A P R S F
// FIN is a TCP flag
FIN uint16 = 1 << iota
// SYN is a TCP flag
@ -52,11 +56,16 @@ const (
)
type tcpPacket struct {
SrcPort uint16 // 0
DestPort uint16 // 2
Seq uint32 // 4
Ack uint32 // 8
Flags uint16 // 13
SrcPort uint16 // 0
DestPort uint16 // 2
Seq uint32 // 4
Ack uint32 // 8
// Flags bytes includes
// Data Offset. 4 bits.
// reserved. 3 bits. (must be zero)
// ECN, Explicit Congestion Notification. 3 bits.
// Control Bits (Real flags). 6 bits.
Flags uint16 // 12
WindowSize uint16 // 14
Checksum uint16 // 16
UrgentPtr uint16 // 18
@ -133,16 +142,29 @@ func (t *tcpPacket) encode(src, dest net.IP, data []byte) []byte {
func checksumTCP(src, dest net.IP, tcpHeader, data []byte) uint16 {
log.Printf("calling checksumTCP: %v %v %v %v", src, dest, tcpHeader, data)
chk := &tcpChecksumer{}
chk := &tcpChecksummer{}
// Encode pseudoheader.
chk.add(src.To4())
chk.add(dest.To4())
if src.To4() != nil {
// IPv4 [ src (4) | dst (4) | rsv (1) | proto (1) | tcp length (2) ] ... | tcp header | data
chk.add(src.To4())
chk.add(dest.To4())
pseudoHeader := make([]byte, 4)
pseudoHeader[1] = tcpProtoNum
binary.BigEndian.PutUint16(pseudoHeader[2:], uint16(len(data)+len(tcpHeader)))
chk.add(pseudoHeader)
} else {
// https://tools.ietf.org/html/rfc2460 IPv6
// IPv6 [ src (16) | dst (16) | payload length (4) | Zero (3) | NH/proto (1) ] ... | tcp header | data
chk.add(src.To16())
chk.add(dest.To16())
pseudoHeader := make([]byte, 8)
binary.BigEndian.PutUint32(pseudoHeader, uint32(len(data)+len(tcpHeader)))
pseudoHeader[7] = tcpProtoNum
chk.add(pseudoHeader)
}
var pseudoHeader [4]byte
pseudoHeader[1] = tcpProtoNum
binary.BigEndian.PutUint16(pseudoHeader[2:], uint16(len(data)+len(tcpHeader)))
chk.add(pseudoHeader[:])
chk.add(tcpHeader)
chk.add(data)
@ -151,13 +173,13 @@ func checksumTCP(src, dest net.IP, tcpHeader, data []byte) uint16 {
return chk.finalize()
}
type tcpChecksumer struct {
type tcpChecksummer struct {
sum uint32
oddByte byte
length int
}
func (c *tcpChecksumer) finalize() uint16 {
func (c *tcpChecksummer) finalize() uint16 {
ret := c.sum
if c.length%2 > 0 {
ret += uint32(c.oddByte)
@ -171,7 +193,7 @@ func (c *tcpChecksumer) finalize() uint16 {
return ^uint16(ret)
}
func (c *tcpChecksumer) add(data []byte) {
func (c *tcpChecksummer) add(data []byte) {
if len(data) == 0 {
return
}

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@ -0,0 +1,91 @@
/*
Copyright 2019 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
// Partially copied from https://github.com/bowei/lighthouse/blob/master/pkg/probe/tcp_test.go
package main
import (
"testing"
)
func TestTCPChecksummer(t *testing.T) {
t.Parallel()
for _, tc := range []struct {
desc string
data [][]byte
want uint16
}{
{
desc: "empty",
data: [][]byte{},
want: 0xffff,
},
{
desc: "1 byte",
data: [][]byte{{0x55}},
want: 0xffaa,
},
{
desc: "2 bytes",
data: [][]byte{{0x55, 0x88}},
want: 0x77aa,
},
{
desc: "3 bytes",
data: [][]byte{{0x55, 0x88, 0x99}},
want: 0x7711,
},
{
desc: "3 bytes / 1 at a time",
data: [][]byte{{0x55}, {0x88}, {0x99}},
want: 0x7711,
},
{
desc: "3 bytes / 2 1",
data: [][]byte{{0x55, 0x88}, {0x99}},
want: 0x7711,
},
{
desc: "simple packet",
data: [][]byte{
{
0x7f, 0x00, 0x00, 0x01, // 127.0.0.1
0x7f, 0x00, 0x00, 0x01, // 127.0.0.1
0x00, 0x06, // TCP proto 6
0x00, 0x14, // Size = 20 bytes
0x00, 0x50, 0x1f, 0x90, 0x00,
0x00, 0x00, 0x01, 0x00, 0x00,
0x00, 0x00, 0x50, 0x02, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00,
},
},
want: 0xff91,
},
} {
t.Run(tc.desc, func(t *testing.T) {
c := &tcpChecksummer{}
for _, b := range tc.data {
c.add(b)
}
got := c.finalize()
if got != tc.want {
t.Errorf("c.finalize() = %x, want %x; bytes: %v", got, tc.want, tc.data)
}
})
}
}