network enhanecment / refactor (#361)

* chore(network): improve connectivity check

* refactor(network): rewrite network and timesync component

* feat(display): show cloud connection status

* chore: change logging verbosity

* chore(websecure): update log message

* fix(ota): validate root certificate when downloading update

* feat(ui): add network settings tab

* fix(display): cloud connecting animation

* fix: golintci issues

* feat: add network settings tab

* feat(timesync): query servers in parallel

* refactor(network): move to internal/network package

* feat(timesync): add metrics

* refactor(log): move log to internal/logging package

* refactor(mdms): move mdns to internal/mdns package

* feat(developer): add pprof endpoint

* feat(logging): add a simple logging streaming endpoint

* fix(mdns): do not start mdns until network is up

* feat(network): allow users to update network settings from ui

* fix(network): handle errors when net.IPAddr is nil

* fix(mdns): scopedLogger SIGSEGV

* fix(dhcp): watch directory instead of file to catch fsnotify.Create event

* refactor(nbd): move platform-specific code to different files

* refactor(native): move platform-specific code to different files

* chore: fix linter issues

* chore(dev_deploy): allow to override PION_LOG_TRACE

internal/network/hostname.go

@@ -0,0 +1,137 @@
+package network
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"strings"
+	"sync"
+
+	"golang.org/x/net/idna"
+)
+
+const (
+	hostnamePath = "/etc/hostname"
+	hostsPath    = "/etc/hosts"
+)
+
+var (
+	hostnameLock sync.Mutex = sync.Mutex{}
+)
+
+func updateEtcHosts(hostname string, fqdn string) error {
+	// update /etc/hosts
+	hostsFile, err := os.OpenFile(hostsPath, os.O_RDWR|os.O_SYNC, os.ModeExclusive)
+	if err != nil {
+		return fmt.Errorf("failed to open %s: %w", hostsPath, err)
+	}
+	defer hostsFile.Close()
+
+	// read all lines
+	if _, err := hostsFile.Seek(0, io.SeekStart); err != nil {
+		return fmt.Errorf("failed to seek %s: %w", hostsPath, err)
+	}
+
+	lines, err := io.ReadAll(hostsFile)
+	if err != nil {
+		return fmt.Errorf("failed to read %s: %w", hostsPath, err)
+	}
+
+	newLines := []string{}
+	hostLine := fmt.Sprintf("127.0.1.1\t%s %s", hostname, fqdn)
+	hostLineExists := false
+
+	for _, line := range strings.Split(string(lines), "\n") {
+		if strings.HasPrefix(line, "127.0.1.1") {
+			hostLineExists = true
+			line = hostLine
+		}
+		newLines = append(newLines, line)
+	}
+
+	if !hostLineExists {
+		newLines = append(newLines, hostLine)
+	}
+
+	if err := hostsFile.Truncate(0); err != nil {
+		return fmt.Errorf("failed to truncate %s: %w", hostsPath, err)
+	}
+
+	if _, err := hostsFile.Seek(0, io.SeekStart); err != nil {
+		return fmt.Errorf("failed to seek %s: %w", hostsPath, err)
+	}
+
+	if _, err := hostsFile.Write([]byte(strings.Join(newLines, "\n"))); err != nil {
+		return fmt.Errorf("failed to write %s: %w", hostsPath, err)
+	}
+
+	return nil
+}
+
+func ToValidHostname(hostname string) string {
+	ascii, err := idna.Lookup.ToASCII(hostname)
+	if err != nil {
+		return ""
+	}
+	return ascii
+}
+
+func SetHostname(hostname string, fqdn string) error {
+	hostnameLock.Lock()
+	defer hostnameLock.Unlock()
+
+	hostname = ToValidHostname(strings.TrimSpace(hostname))
+	fqdn = ToValidHostname(strings.TrimSpace(fqdn))
+
+	if hostname == "" {
+		return fmt.Errorf("invalid hostname: %s", hostname)
+	}
+
+	if fqdn == "" {
+		fqdn = hostname
+	}
+
+	// update /etc/hostname
+	if err := os.WriteFile(hostnamePath, []byte(hostname), 0644); err != nil {
+		return fmt.Errorf("failed to write %s: %w", hostnamePath, err)
+	}
+
+	// update /etc/hosts
+	if err := updateEtcHosts(hostname, fqdn); err != nil {
+		return fmt.Errorf("failed to update /etc/hosts: %w", err)
+	}
+
+	// run hostname
+	if err := exec.Command("hostname", "-F", hostnamePath).Run(); err != nil {
+		return fmt.Errorf("failed to run hostname: %w", err)
+	}
+
+	return nil
+}
+
+func (s *NetworkInterfaceState) setHostnameIfNotSame() error {
+	hostname := s.GetHostname()
+	currentHostname, _ := os.Hostname()
+
+	fqdn := fmt.Sprintf("%s.%s", hostname, s.GetDomain())
+
+	if currentHostname == hostname && s.currentFqdn == fqdn && s.currentHostname == hostname {
+		return nil
+	}
+
+	scopedLogger := s.l.With().Str("hostname", hostname).Str("fqdn", fqdn).Logger()
+
+	err := SetHostname(hostname, fqdn)
+	if err != nil {
+		scopedLogger.Error().Err(err).Msg("failed to set hostname")
+		return err
+	}
+
+	s.currentHostname = hostname
+	s.currentFqdn = fqdn
+
+	scopedLogger.Info().Msg("hostname set")
+
+	return nil
+}