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Merge pull request #58520 from porridge/fix-connreset

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Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Make IsConnectionReset work with more error implementations.

**What this PR does / why we need it**:
This fixes the code to correctly navigate error hierarchy, and actually
work.

**Which issue(s) this PR fixes**
An improvement for #55860

**Special notes for your reviewer**:

Integration-testing this code is somewhat hard. What I did to reproduce this
condition reliably was:

1. use iptables to let the TCP handshake packets through but reject
payload-carrying packets with:
```
sudo iptables -t raw -I PREROUTING -d localhost --protocol tcp --dport 443  -j NOTRACK
sudo iptables -t filter -I INPUT -d localhost --protocol tcp --dport 443 -m string --algo bm --string http  -j REJECT --reject-with tcp-reset
```
2. start a dummy server with: `nc -l -4 localhost 443`
3. make the client issue a GET on localhost:443

Then I added instrumentation to the place in k8s.io/client-go/rest/request.go
which calls this code, to discover the actual error hierarchy.

I think another way to test this would be to run a dummy server which would
listen() on a socket, accept() and then close() the incoming connection
straight away.

**Release note**:
```release-note
Correctly handle transient connection reset errors on GET requests from client library.
```
This commit is contained in:
Kubernetes Submit Queue 2018-01-20 05:37:25 -08:00 committed by GitHub
commit c9c6901303
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1 changed files with 12 additions and 2 deletions
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14
staging/src/k8s.io/apimachinery/pkg/util/net/util.go
View File

@ -18,6 +18,8 @@ package net
import (
"net"
"net/url"
"os"
"reflect"
"syscall"
)
@ -38,8 +40,16 @@ func IPNetEqual(ipnet1, ipnet2 *net.IPNet) bool {
// Returns if the given err is "connection reset by peer" error.
func IsConnectionReset(err error) bool {
opErr, ok := err.(*net.OpError)
if ok && opErr.Err.Error() == syscall.ECONNRESET.Error() {
if urlErr, ok := err.(*url.Error); ok {
err = urlErr.Err
}
if opErr, ok := err.(*net.OpError); ok {
err = opErr.Err
}
if osErr, ok := err.(*os.SyscallError); ok {
err = osErr.Err
}
if errno, ok := err.(syscall.Errno); ok && errno == syscall.ECONNRESET {
return true
}
return false