582 lines
15 KiB
Go
582 lines
15 KiB
Go
package dhcpd
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import (
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"encoding/json"
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"errors"
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"fmt"
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"io/ioutil"
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"net"
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"net/http"
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"os"
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"strings"
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"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
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"github.com/AdguardTeam/golibs/log"
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)
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func httpError(r *http.Request, w http.ResponseWriter, code int, format string, args ...interface{}) {
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text := fmt.Sprintf(format, args...)
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log.Info("DHCP: %s %s: %s", r.Method, r.URL, text)
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http.Error(w, text, code)
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}
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type v4ServerConfJSON struct {
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GatewayIP net.IP `json:"gateway_ip"`
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SubnetMask net.IP `json:"subnet_mask"`
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RangeStart net.IP `json:"range_start"`
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RangeEnd net.IP `json:"range_end"`
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LeaseDuration uint32 `json:"lease_duration"`
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}
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func v4JSONToServerConf(j *v4ServerConfJSON) V4ServerConf {
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if j == nil {
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return V4ServerConf{}
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}
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return V4ServerConf{
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GatewayIP: j.GatewayIP,
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SubnetMask: j.SubnetMask,
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RangeStart: j.RangeStart,
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RangeEnd: j.RangeEnd,
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LeaseDuration: j.LeaseDuration,
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}
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}
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type v6ServerConfJSON struct {
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RangeStart net.IP `json:"range_start"`
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LeaseDuration uint32 `json:"lease_duration"`
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}
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func v6JSONToServerConf(j *v6ServerConfJSON) V6ServerConf {
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if j == nil {
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return V6ServerConf{}
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}
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return V6ServerConf{
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RangeStart: j.RangeStart,
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LeaseDuration: j.LeaseDuration,
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}
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}
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// dhcpStatusResponse is the response for /control/dhcp/status endpoint.
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type dhcpStatusResponse struct {
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Enabled bool `json:"enabled"`
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IfaceName string `json:"interface_name"`
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V4 V4ServerConf `json:"v4"`
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V6 V6ServerConf `json:"v6"`
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Leases []Lease `json:"leases"`
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StaticLeases []Lease `json:"static_leases"`
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}
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func (s *Server) handleDHCPStatus(w http.ResponseWriter, r *http.Request) {
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status := &dhcpStatusResponse{
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Enabled: s.conf.Enabled,
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IfaceName: s.conf.InterfaceName,
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V4: V4ServerConf{},
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V6: V6ServerConf{},
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}
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s.srv4.WriteDiskConfig4(&status.V4)
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s.srv6.WriteDiskConfig6(&status.V6)
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status.Leases = s.Leases(LeasesDynamic)
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status.StaticLeases = s.Leases(LeasesStatic)
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w.Header().Set("Content-Type", "application/json")
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err := json.NewEncoder(w).Encode(status)
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if err != nil {
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httpError(r, w, http.StatusInternalServerError, "Unable to marshal DHCP status json: %s", err)
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return
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}
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}
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func (s *Server) enableDHCP(ifaceName string) (code int, err error) {
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var hasStaticIP bool
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hasStaticIP, err = aghnet.IfaceHasStaticIP(ifaceName)
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if err != nil {
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if errors.Is(err, os.ErrPermission) {
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// ErrPermission may happen here on Linux systems where
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// AdGuard Home is installed using Snap. That doesn't
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// necessarily mean that the machine doesn't have
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// a static IP, so we can assume that it has and go on.
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// If the machine doesn't, we'll get an error later.
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//
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// See https://github.com/AdguardTeam/AdGuardHome/issues/2667.
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//
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// TODO(a.garipov): I was thinking about moving this
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// into IfaceHasStaticIP, but then we wouldn't be able
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// to log it. Think about it more.
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log.Info("error while checking static ip: %s; "+
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"assuming machine has static ip and going on", err)
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hasStaticIP = true
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} else if errors.Is(err, aghnet.ErrNoStaticIPInfo) {
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// Couldn't obtain a definitive answer. Assume static
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// IP an go on.
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log.Info("can't check for static ip; " +
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"assuming machine has static ip and going on")
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hasStaticIP = true
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} else {
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err = fmt.Errorf("checking static ip: %w", err)
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return http.StatusInternalServerError, err
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}
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}
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if !hasStaticIP {
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err = aghnet.IfaceSetStaticIP(ifaceName)
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if err != nil {
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err = fmt.Errorf("setting static ip: %w", err)
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return http.StatusInternalServerError, err
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}
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}
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err = s.Start()
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if err != nil {
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return http.StatusBadRequest, fmt.Errorf("starting dhcp server: %w", err)
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}
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return 0, nil
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}
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type dhcpServerConfigJSON struct {
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V4 *v4ServerConfJSON `json:"v4"`
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V6 *v6ServerConfJSON `json:"v6"`
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InterfaceName string `json:"interface_name"`
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Enabled nullBool `json:"enabled"`
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}
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func (s *Server) handleDHCPSetConfig(w http.ResponseWriter, r *http.Request) {
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conf := dhcpServerConfigJSON{}
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conf.Enabled = boolToNullBool(s.conf.Enabled)
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conf.InterfaceName = s.conf.InterfaceName
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err := json.NewDecoder(r.Body).Decode(&conf)
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if err != nil {
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httpError(r, w, http.StatusBadRequest,
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"failed to parse new dhcp config json: %s", err)
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return
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}
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var s4 DHCPServer
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var s6 DHCPServer
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v4Enabled := false
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v6Enabled := false
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if conf.V4 != nil {
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v4Conf := v4JSONToServerConf(conf.V4)
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v4Conf.Enabled = conf.Enabled == nbTrue
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if len(v4Conf.RangeStart) == 0 {
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v4Conf.Enabled = false
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}
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v4Enabled = v4Conf.Enabled
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v4Conf.InterfaceName = conf.InterfaceName
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c4 := V4ServerConf{}
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s.srv4.WriteDiskConfig4(&c4)
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v4Conf.notify = c4.notify
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v4Conf.ICMPTimeout = c4.ICMPTimeout
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s4, err = v4Create(v4Conf)
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if err != nil {
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httpError(r, w, http.StatusBadRequest,
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"invalid dhcpv4 configuration: %s", err)
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return
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}
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}
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if conf.V6 != nil {
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v6Conf := v6JSONToServerConf(conf.V6)
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v6Conf.Enabled = conf.Enabled == nbTrue
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if len(v6Conf.RangeStart) == 0 {
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v6Conf.Enabled = false
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}
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// Don't overwrite the RA/SLAAC settings from the config file.
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//
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// TODO(a.garipov): Perhaps include them into the request to
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// allow changing them from the HTTP API?
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v6Conf.RASLAACOnly = s.conf.Conf6.RASLAACOnly
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v6Conf.RAAllowSLAAC = s.conf.Conf6.RAAllowSLAAC
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v6Enabled = v6Conf.Enabled
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v6Conf.InterfaceName = conf.InterfaceName
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v6Conf.notify = s.onNotify
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s6, err = v6Create(v6Conf)
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if err != nil {
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httpError(r, w, http.StatusBadRequest,
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"invalid dhcpv6 configuration: %s", err)
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return
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}
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}
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if conf.Enabled == nbTrue && !v4Enabled && !v6Enabled {
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httpError(r, w, http.StatusBadRequest,
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"dhcpv4 or dhcpv6 configuration must be complete")
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return
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}
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s.Stop()
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if conf.Enabled != nbNull {
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s.conf.Enabled = conf.Enabled == nbTrue
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}
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if conf.InterfaceName != "" {
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s.conf.InterfaceName = conf.InterfaceName
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}
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if s4 != nil {
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s.srv4 = s4
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}
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if s6 != nil {
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s.srv6 = s6
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}
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s.conf.ConfigModified()
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s.dbLoad()
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if s.conf.Enabled {
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var code int
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code, err = s.enableDHCP(conf.InterfaceName)
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if err != nil {
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httpError(r, w, code, "enabling dhcp: %s", err)
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return
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}
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}
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}
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type netInterfaceJSON struct {
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Name string `json:"name"`
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GatewayIP net.IP `json:"gateway_ip"`
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HardwareAddr string `json:"hardware_address"`
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Addrs4 []net.IP `json:"ipv4_addresses"`
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Addrs6 []net.IP `json:"ipv6_addresses"`
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Flags string `json:"flags"`
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}
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func (s *Server) handleDHCPInterfaces(w http.ResponseWriter, r *http.Request) {
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response := map[string]netInterfaceJSON{}
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ifaces, err := net.Interfaces()
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if err != nil {
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httpError(r, w, http.StatusInternalServerError, "Couldn't get interfaces: %s", err)
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return
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}
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for _, iface := range ifaces {
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if iface.Flags&net.FlagLoopback != 0 {
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// it's a loopback, skip it
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continue
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}
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if iface.Flags&net.FlagBroadcast == 0 {
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// this interface doesn't support broadcast, skip it
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continue
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}
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var addrs []net.Addr
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addrs, err = iface.Addrs()
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if err != nil {
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httpError(r, w, http.StatusInternalServerError, "Failed to get addresses for interface %s: %s", iface.Name, err)
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return
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}
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jsonIface := netInterfaceJSON{
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Name: iface.Name,
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HardwareAddr: iface.HardwareAddr.String(),
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}
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if iface.Flags != 0 {
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jsonIface.Flags = iface.Flags.String()
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}
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// we don't want link-local addresses in json, so skip them
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for _, addr := range addrs {
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ipnet, ok := addr.(*net.IPNet)
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if !ok {
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// not an IPNet, should not happen
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httpError(r, w, http.StatusInternalServerError, "SHOULD NOT HAPPEN: got iface.Addrs() element %s that is not net.IPNet, it is %T", addr, addr)
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return
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}
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// ignore link-local
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if ipnet.IP.IsLinkLocalUnicast() {
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continue
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}
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if ipnet.IP.To4() != nil {
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jsonIface.Addrs4 = append(jsonIface.Addrs4, ipnet.IP)
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} else {
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jsonIface.Addrs6 = append(jsonIface.Addrs6, ipnet.IP)
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}
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}
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if len(jsonIface.Addrs4)+len(jsonIface.Addrs6) != 0 {
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jsonIface.GatewayIP = aghnet.GatewayIP(iface.Name)
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response[iface.Name] = jsonIface
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}
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}
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err = json.NewEncoder(w).Encode(response)
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if err != nil {
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httpError(r, w, http.StatusInternalServerError, "Failed to marshal json with available interfaces: %s", err)
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return
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}
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}
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// dhcpSearchOtherResult contains information about other DHCP server for
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// specific network interface.
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type dhcpSearchOtherResult struct {
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Found string `json:"found,omitempty"`
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Error string `json:"error,omitempty"`
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}
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// dhcpStaticIPStatus contains information about static IP address for DHCP
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// server.
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type dhcpStaticIPStatus struct {
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Static string `json:"static"`
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IP string `json:"ip,omitempty"`
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Error string `json:"error,omitempty"`
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}
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// dhcpSearchV4Result contains information about DHCPv4 server for specific
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// network interface.
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type dhcpSearchV4Result struct {
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OtherServer dhcpSearchOtherResult `json:"other_server"`
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StaticIP dhcpStaticIPStatus `json:"static_ip"`
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}
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// dhcpSearchV6Result contains information about DHCPv6 server for specific
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// network interface.
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type dhcpSearchV6Result struct {
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OtherServer dhcpSearchOtherResult `json:"other_server"`
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}
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// dhcpSearchResult is a response for /control/dhcp/find_active_dhcp endpoint.
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type dhcpSearchResult struct {
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V4 dhcpSearchV4Result `json:"v4"`
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V6 dhcpSearchV6Result `json:"v6"`
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}
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// Perform the following tasks:
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// . Search for another DHCP server running
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// . Check if a static IP is configured for the network interface
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// Respond with results
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func (s *Server) handleDHCPFindActiveServer(w http.ResponseWriter, r *http.Request) {
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// This use of ReadAll is safe, because request's body is now limited.
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body, err := ioutil.ReadAll(r.Body)
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if err != nil {
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msg := fmt.Sprintf("failed to read request body: %s", err)
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log.Error(msg)
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http.Error(w, msg, http.StatusBadRequest)
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return
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}
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interfaceName := strings.TrimSpace(string(body))
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if interfaceName == "" {
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msg := "empty interface name specified"
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log.Error(msg)
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http.Error(w, msg, http.StatusBadRequest)
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return
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}
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result := dhcpSearchResult{
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V4: dhcpSearchV4Result{
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OtherServer: dhcpSearchOtherResult{},
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StaticIP: dhcpStaticIPStatus{},
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},
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V6: dhcpSearchV6Result{
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OtherServer: dhcpSearchOtherResult{},
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},
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}
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found4, err4 := CheckIfOtherDHCPServersPresentV4(interfaceName)
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isStaticIP, err := aghnet.IfaceHasStaticIP(interfaceName)
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if err != nil {
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result.V4.StaticIP.Static = "error"
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result.V4.StaticIP.Error = err.Error()
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} else if !isStaticIP {
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result.V4.StaticIP.Static = "no"
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result.V4.StaticIP.IP = aghnet.GetSubnet(interfaceName).String()
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}
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if found4 {
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result.V4.OtherServer.Found = "yes"
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} else if err4 != nil {
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result.V4.OtherServer.Found = "error"
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result.V4.OtherServer.Error = err4.Error()
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}
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found6, err6 := CheckIfOtherDHCPServersPresentV6(interfaceName)
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if found6 {
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result.V6.OtherServer.Found = "yes"
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} else if err6 != nil {
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result.V6.OtherServer.Found = "error"
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result.V6.OtherServer.Error = err6.Error()
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}
|
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w.Header().Set("Content-Type", "application/json")
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err = json.NewEncoder(w).Encode(result)
|
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if err != nil {
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httpError(r, w, http.StatusInternalServerError, "Failed to marshal DHCP found json: %s", err)
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return
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}
|
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}
|
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|
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func (s *Server) handleDHCPAddStaticLease(w http.ResponseWriter, r *http.Request) {
|
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lj := Lease{}
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err := json.NewDecoder(r.Body).Decode(&lj)
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if err != nil {
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httpError(r, w, http.StatusBadRequest, "json.Decode: %s", err)
|
|
|
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return
|
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}
|
|
|
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if lj.IP == nil {
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httpError(r, w, http.StatusBadRequest, "invalid IP")
|
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|
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return
|
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}
|
|
|
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ip4 := lj.IP.To4()
|
|
|
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if ip4 == nil {
|
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lj.IP = lj.IP.To16()
|
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|
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err = s.srv6.AddStaticLease(lj)
|
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if err != nil {
|
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httpError(r, w, http.StatusBadRequest, "%s", err)
|
|
}
|
|
|
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return
|
|
}
|
|
|
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lj.IP = ip4
|
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err = s.srv4.AddStaticLease(lj)
|
|
if err != nil {
|
|
httpError(r, w, http.StatusBadRequest, "%s", err)
|
|
|
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return
|
|
}
|
|
}
|
|
|
|
func (s *Server) handleDHCPRemoveStaticLease(w http.ResponseWriter, r *http.Request) {
|
|
lj := Lease{}
|
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err := json.NewDecoder(r.Body).Decode(&lj)
|
|
if err != nil {
|
|
httpError(r, w, http.StatusBadRequest, "json.Decode: %s", err)
|
|
|
|
return
|
|
}
|
|
|
|
if lj.IP == nil {
|
|
httpError(r, w, http.StatusBadRequest, "invalid IP")
|
|
|
|
return
|
|
}
|
|
|
|
ip4 := lj.IP.To4()
|
|
|
|
if ip4 == nil {
|
|
lj.IP = lj.IP.To16()
|
|
|
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err = s.srv6.RemoveStaticLease(lj)
|
|
if err != nil {
|
|
httpError(r, w, http.StatusBadRequest, "%s", err)
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
lj.IP = ip4
|
|
err = s.srv4.RemoveStaticLease(lj)
|
|
if err != nil {
|
|
httpError(r, w, http.StatusBadRequest, "%s", err)
|
|
|
|
return
|
|
}
|
|
}
|
|
|
|
func (s *Server) handleReset(w http.ResponseWriter, r *http.Request) {
|
|
s.Stop()
|
|
|
|
err := os.Remove(s.conf.DBFilePath)
|
|
if err != nil && !errors.Is(err, os.ErrNotExist) {
|
|
log.Error("dhcp: removing %q: %s", s.conf.DBFilePath, err)
|
|
}
|
|
|
|
oldconf := s.conf
|
|
s.conf = ServerConfig{}
|
|
s.conf.WorkDir = oldconf.WorkDir
|
|
s.conf.HTTPRegister = oldconf.HTTPRegister
|
|
s.conf.ConfigModified = oldconf.ConfigModified
|
|
s.conf.DBFilePath = oldconf.DBFilePath
|
|
|
|
v4conf := V4ServerConf{}
|
|
v4conf.ICMPTimeout = 1000
|
|
v4conf.notify = s.onNotify
|
|
s.srv4, _ = v4Create(v4conf)
|
|
|
|
v6conf := V6ServerConf{}
|
|
v6conf.notify = s.onNotify
|
|
s.srv6, _ = v6Create(v6conf)
|
|
|
|
s.conf.ConfigModified()
|
|
}
|
|
|
|
func (s *Server) registerHandlers() {
|
|
s.conf.HTTPRegister(http.MethodGet, "/control/dhcp/status", s.handleDHCPStatus)
|
|
s.conf.HTTPRegister(http.MethodGet, "/control/dhcp/interfaces", s.handleDHCPInterfaces)
|
|
s.conf.HTTPRegister(http.MethodPost, "/control/dhcp/set_config", s.handleDHCPSetConfig)
|
|
s.conf.HTTPRegister(http.MethodPost, "/control/dhcp/find_active_dhcp", s.handleDHCPFindActiveServer)
|
|
s.conf.HTTPRegister(http.MethodPost, "/control/dhcp/add_static_lease", s.handleDHCPAddStaticLease)
|
|
s.conf.HTTPRegister(http.MethodPost, "/control/dhcp/remove_static_lease", s.handleDHCPRemoveStaticLease)
|
|
s.conf.HTTPRegister(http.MethodPost, "/control/dhcp/reset", s.handleReset)
|
|
}
|
|
|
|
// jsonError is a generic JSON error response.
|
|
//
|
|
// TODO(a.garipov): Merge together with the implementations in .../home and
|
|
// other packages after refactoring the web handler registering.
|
|
type jsonError struct {
|
|
// Message is the error message, an opaque string.
|
|
Message string `json:"message"`
|
|
}
|
|
|
|
// notImplemented returns a handler that replies to any request with an HTTP 501
|
|
// Not Implemented status and a JSON error with the provided message msg.
|
|
//
|
|
// TODO(a.garipov): Either take the logger from the server after we've
|
|
// refactored logging or make this not a method of *Server.
|
|
func (s *Server) notImplemented(msg string) (f func(http.ResponseWriter, *http.Request)) {
|
|
return func(w http.ResponseWriter, _ *http.Request) {
|
|
w.Header().Set("Content-Type", "application/json")
|
|
w.WriteHeader(http.StatusNotImplemented)
|
|
|
|
err := json.NewEncoder(w).Encode(&jsonError{
|
|
Message: msg,
|
|
})
|
|
if err != nil {
|
|
log.Debug("writing 501 json response: %s", err)
|
|
}
|
|
}
|
|
}
|
|
|
|
func (s *Server) registerNotImplementedHandlers() {
|
|
h := s.notImplemented("dhcp is not supported on windows")
|
|
|
|
s.conf.HTTPRegister(http.MethodGet, "/control/dhcp/status", h)
|
|
s.conf.HTTPRegister(http.MethodGet, "/control/dhcp/interfaces", h)
|
|
s.conf.HTTPRegister(http.MethodPost, "/control/dhcp/set_config", h)
|
|
s.conf.HTTPRegister(http.MethodPost, "/control/dhcp/find_active_dhcp", h)
|
|
s.conf.HTTPRegister(http.MethodPost, "/control/dhcp/add_static_lease", h)
|
|
s.conf.HTTPRegister(http.MethodPost, "/control/dhcp/remove_static_lease", h)
|
|
s.conf.HTTPRegister(http.MethodPost, "/control/dhcp/reset", h)
|
|
}
|