kubernetes/test/images/regression-issue-74839/main.go
2021-08-20 10:42:09 +02:00

153 lines
3.4 KiB
Go

/*
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.
*/
package main
import (
"fmt"
"log"
"net"
"os"
"strings"
"time"
netutils "k8s.io/utils/net"
)
// TCP port to listen
const port = 9000
func main() {
ips := getIPs()
if len(ips) == 0 {
panic("No valid IP found")
}
// 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:%d", "0.0.0.0", port)
// 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)
}
for {
conn, err := listener.Accept()
if err != nil {
panic(err)
}
go func(conn net.Conn) {
// Close the connection after 10 secs
time.Sleep(10 * time.Second)
conn.Close()
}(conn)
}
}
func probe(ip string) {
log.Printf("probing %v", ip)
ipAddr, err := net.ResolveIPAddr("ip:tcp", ip)
if err != nil {
panic(err)
}
conn, err := net.ListenIP("ip:tcp", ipAddr)
if err != nil {
panic(err)
}
pending := make(map[string]uint32)
var buffer [4096]byte
for {
n, addr, err := conn.ReadFrom(buffer[:])
if err != nil {
log.Printf("conn.ReadFrom() error: %v", err)
continue
}
pkt := &tcpPacket{}
data, err := pkt.decode(buffer[:n])
if err != nil {
log.Printf("tcp packet parse error: %v", err)
continue
}
if pkt.DestPort != 9000 {
continue
}
log.Printf("tcp packet: %+v, flag: %v, data: %v, addr: %v", pkt, pkt.FlagString(), data, addr)
if pkt.Flags&SYN != 0 {
pending[addr.String()] = pkt.Seq + 1
continue
}
if pkt.Flags&RST != 0 {
log.Println("ERROR: RST received")
}
if pkt.Flags&ACK != 0 {
if seq, ok := pending[addr.String()]; ok {
log.Println("connection established")
delete(pending, addr.String())
badPkt := &tcpPacket{
SrcPort: pkt.DestPort,
DestPort: pkt.SrcPort,
Ack: seq,
Seq: pkt.Ack - 100000, // Bad: seq out-of-window
Flags: (5 << 12) | PSH | ACK, // Offset and Flags oooo000F FFFFFFFF (o:offset, F:flags)
WindowSize: pkt.WindowSize,
}
data := []byte("boom!!!")
remoteIP := netutils.ParseIPSloppy(addr.String())
localIP := netutils.ParseIPSloppy(conn.LocalAddr().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")
}
}
}
}
}
// 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, netutils.ParseIPSloppy(ip))
}
} else if podIP != "" {
ips = append(ips, netutils.ParseIPSloppy(podIP))
}
return ips
}