63 lines
1.4 KiB
Go
63 lines
1.4 KiB
Go
package main
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import (
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"bytes"
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"fmt"
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"log"
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"os"
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"golang.org/x/crypto/ssh"
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)
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const (
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sshKeyPathEnvVarName = "SSH_KEY"
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setupOpenWRTDNSFlagName = "setup-openwrt-dns"
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setupOpenWRTNewDNSFlagName = "new-dns"
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openWRTUser = "root"
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openWRTHost = "192.168.1.1:22" // Using IP because assuming DNS is down
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)
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var (
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sshKeyPath, _ = os.LookupEnv(sshKeyPathEnvVarName)
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)
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// SetOpenWRTDNS ssh-es into `host` and sets `dns` as it's primary dns for dnsmasq
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func SetOpenWRTDNS(privateKey []byte, dns string) (string, error) {
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signer, err := ssh.ParsePrivateKey(privateKey)
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if err != nil {
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log.Fatalf("unable to parse private key: %v", err)
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}
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config := &ssh.ClientConfig{
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User: openWRTUser,
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Auth: []ssh.AuthMethod{
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ssh.PublicKeys(signer),
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},
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HostKeyCallback: ssh.InsecureIgnoreHostKey(),
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}
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client, err := ssh.Dial("tcp", openWRTHost, config)
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if err != nil {
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log.Fatal("Failed to dial: ", err)
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}
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defer client.Close()
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session, err := client.NewSession()
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if err != nil {
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log.Fatal("Failed to create session: ", err)
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}
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defer session.Close()
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cmd := openwrtDNSUpdateCmd(dns)
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var b bytes.Buffer
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session.Stdout = &b
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if err := session.Run(cmd); err != nil {
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log.Fatal("Failed to run: " + err.Error())
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}
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fmt.Println(b.String())
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return "", nil
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}
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func openwrtDNSUpdateCmd(newDNS string) string {
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return fmt.Sprintf("sed -i \"s/\\slist server.*/ list server '%s'/\" /etc/config/dhcp && /etc/init.d/dnsmasq reload", newDNS)
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}
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