64 lines
1.4 KiB
Go
64 lines
1.4 KiB
Go
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// Binary dhcp4 obtains a DHCPv4 lease, persists its contents to
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// /perm/dhcp4/wire/lease.json and notifies netconfigd.
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package main
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import (
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"encoding/json"
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"flag"
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"fmt"
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"io/ioutil"
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"log"
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"net"
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"os"
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"path/filepath"
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"syscall"
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"time"
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"router7/internal/dhcp4"
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"router7/internal/notify"
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)
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func logic() error {
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const configPath = "/perm/dhcp4/wire/lease.json"
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if err := os.MkdirAll(filepath.Dir(configPath), 0755); err != nil {
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return err
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}
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iface, err := net.InterfaceByName("uplink0")
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if err != nil {
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return err
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}
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c := dhcp4.Client{
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Interface: iface,
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}
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for c.ObtainOrRenew() {
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if err := c.Err(); err != nil {
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log.Printf("Temporary error: %v", err)
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continue
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}
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// TODO: use a logger which writes to /dev/console
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log.Printf("lease: %+v", c.Config())
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ioutil.WriteFile("/dev/console", []byte(fmt.Sprintf("lease: %+v\n", c.Config())), 0600)
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b, err := json.Marshal(c.Config())
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if err != nil {
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return err
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}
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if err := ioutil.WriteFile(configPath, b, 0644); err != nil {
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return err
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}
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if err := notify.Process("/user/netconfi", syscall.SIGUSR1); err != nil {
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log.Printf("notifying netconfig: %v", err)
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ioutil.WriteFile("/dev/console", []byte(fmt.Sprintf("notifying netconfigd: %+v\n", err)), 0600)
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}
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time.Sleep(time.Until(c.Config().RenewAfter))
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}
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return c.Err() // permanent error
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}
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func main() {
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// TODO: drop privileges, run as separate uid?
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flag.Parse()
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if err := logic(); err != nil {
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log.Fatal(err)
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}
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}
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