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package nsagent
import (
"encoding/json"
"fmt"
"io"
"net"
"os"
"os/signal"
"sort"
"github.com/rootless-containers/bypass4netns/pkg/bypass4netns/nsagent/types"
"github.com/sirupsen/logrus"
"golang.org/x/sys/unix"
)
func Main() error {
w := os.Stdout
if err := inspect(w); err != nil {
return err
}
sigCh := make(chan os.Signal, 1)
signal.Notify(sigCh, unix.SIGHUP, unix.SIGTERM, unix.SIGINT)
for sig := range sigCh {
switch sig {
case unix.SIGHUP:
if err := inspect(w); err != nil {
return err
}
case unix.SIGTERM, unix.SIGINT:
return nil
}
}
return nil
}
func inspect(w io.Writer) error {
var msg types.Message
interfaces, err := net.Interfaces()
if err != nil {
return fmt.Errorf("failed to enumerate the network interfaces: %w", err)
}
for _, intf := range interfaces {
addrs, err := intf.Addrs()
if err != nil {
logrus.Warnf("Failed to get the addresses of the network interface %q: %v", intf.Name, err)
continue
}
entry := types.Interface{
Name: intf.Name,
}
for _, addr := range addrs {
if ipNet, ok := addr.(*net.IPNet); ok {
entry.CIDRs = append(entry.CIDRs, ipNet.String())
}
}
sort.Strings(entry.CIDRs)
msg.Interfaces = append(msg.Interfaces, entry)
}
sort.Slice(msg.Interfaces, func(i, j int) bool {
return msg.Interfaces[i].Name < msg.Interfaces[j].Name
})
b, err := json.Marshal(msg)
if err != nil {
return err
}
b = append(b, []byte("\n")...)
_, err = w.Write(b)
return err
}
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