mirror of
https://github.com/k3s-io/kubernetes.git
synced 2025-10-28 20:30:09 +00:00
128 lines
3.2 KiB
Go
128 lines
3.2 KiB
Go
/*
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Copyright 2019 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package connect
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import (
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"fmt"
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"net"
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"os"
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"syscall"
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"time"
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"github.com/ishidawataru/sctp"
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"github.com/spf13/cobra"
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)
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// CmdConnect is used by agnhost Cobra.
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var CmdConnect = &cobra.Command{
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Use: "connect [host:port]",
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Short: "Attempts a TCP or SCTP connection and returns useful errors",
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Long: `Tries to open a TCP or SCTP connection to the given host and port. On error it prints an error message prefixed with a specific fixed string that test cases can check for:
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* UNKNOWN - Generic/unknown (non-network) error (eg, bad arguments)
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* TIMEOUT - The connection attempt timed out
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* DNS - An error in DNS resolution
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* REFUSED - Connection refused
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* OTHER - Other networking error (eg, "no route to host")`,
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Args: cobra.ExactArgs(1),
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Run: main,
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}
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var timeout time.Duration
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var protocol string
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func init() {
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CmdConnect.Flags().DurationVar(&timeout, "timeout", time.Duration(0), "Maximum time before returning an error")
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CmdConnect.Flags().StringVar(&protocol, "protocol", "tcp", "The protocol to use to perform the connection, can be tcp or sctp")
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}
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func main(cmd *cobra.Command, args []string) {
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dest := args[0]
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switch protocol {
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case "", "tcp":
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connectTCP(dest, timeout)
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case "sctp":
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connectSCTP(dest, timeout)
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default:
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fmt.Fprint(os.Stderr, "Unsupported protocol\n", protocol)
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os.Exit(1)
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}
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}
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func connectTCP(dest string, timeout time.Duration) {
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// Redundantly parse and resolve the destination so we can return the correct
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// errors if there's a problem.
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if _, _, err := net.SplitHostPort(dest); err != nil {
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fmt.Fprintf(os.Stderr, "UNKNOWN: %v\n", err)
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os.Exit(1)
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}
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if _, err := net.ResolveTCPAddr("tcp", dest); err != nil {
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fmt.Fprintf(os.Stderr, "DNS: %v\n", err)
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os.Exit(1)
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}
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conn, err := net.DialTimeout("tcp", dest, timeout)
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if err == nil {
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conn.Close()
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os.Exit(0)
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}
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if opErr, ok := err.(*net.OpError); ok {
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if opErr.Timeout() {
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fmt.Fprintf(os.Stderr, "TIMEOUT\n")
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os.Exit(1)
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} else if syscallErr, ok := opErr.Err.(*os.SyscallError); ok {
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if syscallErr.Err == syscall.ECONNREFUSED {
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fmt.Fprintf(os.Stderr, "REFUSED\n")
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os.Exit(1)
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}
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}
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}
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fmt.Fprintf(os.Stderr, "OTHER: %v\n", err)
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os.Exit(1)
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}
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func connectSCTP(dest string, timeout time.Duration) {
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addr, err := sctp.ResolveSCTPAddr("sctp", dest)
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if err != nil {
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fmt.Fprintf(os.Stderr, "DNS: %v\n", err)
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os.Exit(1)
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}
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timeoutCh := time.After(timeout)
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errCh := make(chan (error))
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go func() {
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conn, err := sctp.DialSCTP("sctp", nil, addr)
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if err == nil {
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conn.Close()
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}
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errCh <- err
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}()
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select {
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case err := <-errCh:
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if err != nil {
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fmt.Fprintf(os.Stderr, "OTHER: %v\n", err)
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os.Exit(1)
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}
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case <-timeoutCh:
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fmt.Fprint(os.Stderr, "TIMEOUT\n")
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os.Exit(1)
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}
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}
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