AdGuardHome/internal/dhcpd/http_unix.go

733 lines
19 KiB
Go

//go:build darwin || freebsd || linux || openbsd
package dhcpd
import (
"encoding/json"
"fmt"
"io"
"net"
"net/http"
"net/netip"
"os"
"time"
"github.com/AdguardTeam/AdGuardHome/internal/aghalg"
"github.com/AdguardTeam/AdGuardHome/internal/aghhttp"
"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
"github.com/AdguardTeam/AdGuardHome/internal/dhcpsvc"
"github.com/AdguardTeam/golibs/errors"
"github.com/AdguardTeam/golibs/log"
"github.com/AdguardTeam/golibs/netutil"
"golang.org/x/exp/slices"
)
type v4ServerConfJSON struct {
GatewayIP netip.Addr `json:"gateway_ip"`
SubnetMask netip.Addr `json:"subnet_mask"`
RangeStart netip.Addr `json:"range_start"`
RangeEnd netip.Addr `json:"range_end"`
LeaseDuration uint32 `json:"lease_duration"`
}
func (j *v4ServerConfJSON) toServerConf() *V4ServerConf {
if j == nil {
return &V4ServerConf{}
}
return &V4ServerConf{
GatewayIP: j.GatewayIP,
SubnetMask: j.SubnetMask,
RangeStart: j.RangeStart,
RangeEnd: j.RangeEnd,
LeaseDuration: j.LeaseDuration,
}
}
type v6ServerConfJSON struct {
RangeStart netip.Addr `json:"range_start"`
LeaseDuration uint32 `json:"lease_duration"`
}
func v6JSONToServerConf(j *v6ServerConfJSON) V6ServerConf {
if j == nil {
return V6ServerConf{}
}
return V6ServerConf{
RangeStart: j.RangeStart.AsSlice(),
LeaseDuration: j.LeaseDuration,
}
}
// dhcpStatusResponse is the response for /control/dhcp/status endpoint.
type dhcpStatusResponse struct {
IfaceName string `json:"interface_name"`
V4 V4ServerConf `json:"v4"`
V6 V6ServerConf `json:"v6"`
Leases []*leaseDynamic `json:"leases"`
StaticLeases []*leaseStatic `json:"static_leases"`
Enabled bool `json:"enabled"`
}
// leaseStatic is the JSON form of static DHCP lease.
type leaseStatic struct {
HWAddr string `json:"mac"`
IP netip.Addr `json:"ip"`
Hostname string `json:"hostname"`
}
// leasesToStatic converts list of leases to their JSON form.
func leasesToStatic(leases []*dhcpsvc.Lease) (static []*leaseStatic) {
static = make([]*leaseStatic, len(leases))
for i, l := range leases {
static[i] = &leaseStatic{
HWAddr: l.HWAddr.String(),
IP: l.IP,
Hostname: l.Hostname,
}
}
return static
}
// toLease converts leaseStatic to Lease or returns error.
func (l *leaseStatic) toLease() (lease *Lease, err error) {
addr, err := net.ParseMAC(l.HWAddr)
if err != nil {
return nil, fmt.Errorf("couldn't parse MAC address: %w", err)
}
return &Lease{
HWAddr: addr,
IP: l.IP,
Hostname: l.Hostname,
IsStatic: true,
}, nil
}
// leaseDynamic is the JSON form of dynamic DHCP lease.
type leaseDynamic struct {
HWAddr string `json:"mac"`
IP netip.Addr `json:"ip"`
Hostname string `json:"hostname"`
Expiry string `json:"expires"`
}
// leasesToDynamic converts list of leases to their JSON form.
func leasesToDynamic(leases []*dhcpsvc.Lease) (dynamic []*leaseDynamic) {
dynamic = make([]*leaseDynamic, len(leases))
for i, l := range leases {
dynamic[i] = &leaseDynamic{
HWAddr: l.HWAddr.String(),
IP: l.IP,
Hostname: l.Hostname,
// The front-end is waiting for RFC 3999 format of the time
// value.
//
// See https://github.com/AdguardTeam/AdGuardHome/issues/2692.
Expiry: l.Expiry.Format(time.RFC3339),
}
}
return dynamic
}
func (s *server) handleDHCPStatus(w http.ResponseWriter, r *http.Request) {
status := &dhcpStatusResponse{
Enabled: s.conf.Enabled,
IfaceName: s.conf.InterfaceName,
V4: V4ServerConf{},
V6: V6ServerConf{},
}
s.srv4.WriteDiskConfig4(&status.V4)
s.srv6.WriteDiskConfig6(&status.V6)
leases := s.Leases()
slices.SortFunc(leases, func(a, b *dhcpsvc.Lease) (res int) {
if a.IsStatic == b.IsStatic {
return 0
} else if a.IsStatic {
return -1
} else {
return 1
}
})
dynamicIdx := slices.IndexFunc(leases, func(l *dhcpsvc.Lease) (ok bool) {
return !l.IsStatic
})
if dynamicIdx == -1 {
dynamicIdx = len(leases)
}
status.Leases = leasesToDynamic(leases[dynamicIdx:])
status.StaticLeases = leasesToStatic(leases[:dynamicIdx])
aghhttp.WriteJSONResponseOK(w, r, status)
}
func (s *server) enableDHCP(ifaceName string) (code int, err error) {
var hasStaticIP bool
hasStaticIP, err = aghnet.IfaceHasStaticIP(ifaceName)
if err != nil {
if errors.Is(err, os.ErrPermission) {
// ErrPermission may happen here on Linux systems where AdGuard Home
// is installed using Snap. That doesn't necessarily mean that the
// machine doesn't have a static IP, so we can assume that it has
// and go on. If the machine doesn't, we'll get an error later.
//
// See https://github.com/AdguardTeam/AdGuardHome/issues/2667.
//
// TODO(a.garipov): I was thinking about moving this into
// IfaceHasStaticIP, but then we wouldn't be able to log it. Think
// about it more.
log.Info("error while checking static ip: %s; "+
"assuming machine has static ip and going on", err)
hasStaticIP = true
} else if errors.Is(err, aghnet.ErrNoStaticIPInfo) {
// Couldn't obtain a definitive answer. Assume static IP an go on.
log.Info("can't check for static ip; " +
"assuming machine has static ip and going on")
hasStaticIP = true
} else {
err = fmt.Errorf("checking static ip: %w", err)
return http.StatusInternalServerError, err
}
}
if !hasStaticIP {
err = aghnet.IfaceSetStaticIP(ifaceName)
if err != nil {
err = fmt.Errorf("setting static ip: %w", err)
return http.StatusInternalServerError, err
}
}
err = s.Start()
if err != nil {
return http.StatusBadRequest, fmt.Errorf("starting dhcp server: %w", err)
}
return 0, nil
}
type dhcpServerConfigJSON struct {
V4 *v4ServerConfJSON `json:"v4"`
V6 *v6ServerConfJSON `json:"v6"`
InterfaceName string `json:"interface_name"`
Enabled aghalg.NullBool `json:"enabled"`
}
func (s *server) handleDHCPSetConfigV4(
conf *dhcpServerConfigJSON,
) (srv DHCPServer, enabled bool, err error) {
if conf.V4 == nil {
return nil, false, nil
}
v4Conf := conf.V4.toServerConf()
v4Conf.Enabled = conf.Enabled == aghalg.NBTrue
if !v4Conf.RangeStart.IsValid() {
v4Conf.Enabled = false
}
v4Conf.InterfaceName = conf.InterfaceName
// Set the default values for the fields not configurable via web API.
c4 := &V4ServerConf{
notify: s.onNotify,
ICMPTimeout: s.conf.Conf4.ICMPTimeout,
Options: s.conf.Conf4.Options,
}
s.srv4.WriteDiskConfig4(c4)
v4Conf.notify = c4.notify
v4Conf.ICMPTimeout = c4.ICMPTimeout
v4Conf.Options = c4.Options
srv4, err := v4Create(v4Conf)
return srv4, srv4.enabled(), err
}
func (s *server) handleDHCPSetConfigV6(
conf *dhcpServerConfigJSON,
) (srv6 DHCPServer, enabled bool, err error) {
if conf.V6 == nil {
return nil, false, nil
}
v6Conf := v6JSONToServerConf(conf.V6)
v6Conf.Enabled = conf.Enabled == aghalg.NBTrue
if len(v6Conf.RangeStart) == 0 {
v6Conf.Enabled = false
}
// Don't overwrite the RA/SLAAC settings from the config file.
//
// TODO(a.garipov): Perhaps include them into the request to allow
// changing them from the HTTP API?
v6Conf.RASLAACOnly = s.conf.Conf6.RASLAACOnly
v6Conf.RAAllowSLAAC = s.conf.Conf6.RAAllowSLAAC
enabled = v6Conf.Enabled
v6Conf.InterfaceName = conf.InterfaceName
v6Conf.notify = s.onNotify
srv6, err = v6Create(v6Conf)
return srv6, enabled, err
}
// createServers returns DHCPv4 and DHCPv6 servers created from the provided
// configuration conf.
func (s *server) createServers(conf *dhcpServerConfigJSON) (srv4, srv6 DHCPServer, err error) {
srv4, v4Enabled, err := s.handleDHCPSetConfigV4(conf)
if err != nil {
return nil, nil, fmt.Errorf("bad dhcpv4 configuration: %w", err)
}
srv6, v6Enabled, err := s.handleDHCPSetConfigV6(conf)
if err != nil {
return nil, nil, fmt.Errorf("bad dhcpv6 configuration: %w", err)
}
if conf.Enabled == aghalg.NBTrue && !v4Enabled && !v6Enabled {
return nil, nil, fmt.Errorf("dhcpv4 or dhcpv6 configuration must be complete")
}
return srv4, srv6, nil
}
// handleDHCPSetConfig is the handler for the POST /control/dhcp/set_config
// HTTP API.
func (s *server) handleDHCPSetConfig(w http.ResponseWriter, r *http.Request) {
conf := &dhcpServerConfigJSON{}
conf.Enabled = aghalg.BoolToNullBool(s.conf.Enabled)
conf.InterfaceName = s.conf.InterfaceName
err := json.NewDecoder(r.Body).Decode(conf)
if err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "failed to parse new dhcp config json: %s", err)
return
}
srv4, srv6, err := s.createServers(conf)
if err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "%s", err)
return
}
err = s.Stop()
if err != nil {
aghhttp.Error(r, w, http.StatusInternalServerError, "stopping dhcp: %s", err)
return
}
s.setConfFromJSON(conf, srv4, srv6)
s.conf.ConfigModified()
err = s.dbLoad()
if err != nil {
aghhttp.Error(r, w, http.StatusInternalServerError, "loading leases db: %s", err)
return
}
if s.conf.Enabled {
var code int
code, err = s.enableDHCP(conf.InterfaceName)
if err != nil {
aghhttp.Error(r, w, code, "enabling dhcp: %s", err)
}
}
}
// setConfFromJSON sets configuration parameters in s from the new configuration
// decoded from JSON.
func (s *server) setConfFromJSON(conf *dhcpServerConfigJSON, srv4, srv6 DHCPServer) {
if conf.Enabled != aghalg.NBNull {
s.conf.Enabled = conf.Enabled == aghalg.NBTrue
}
if conf.InterfaceName != "" {
s.conf.InterfaceName = conf.InterfaceName
}
if srv4 != nil {
s.srv4 = srv4
}
if srv6 != nil {
s.srv6 = srv6
}
}
type netInterfaceJSON struct {
Name string `json:"name"`
HardwareAddr string `json:"hardware_address"`
Flags string `json:"flags"`
GatewayIP netip.Addr `json:"gateway_ip"`
Addrs4 []netip.Addr `json:"ipv4_addresses"`
Addrs6 []netip.Addr `json:"ipv6_addresses"`
}
// handleDHCPInterfaces is the handler for the GET /control/dhcp/interfaces
// HTTP API.
func (s *server) handleDHCPInterfaces(w http.ResponseWriter, r *http.Request) {
resp := map[string]*netInterfaceJSON{}
ifaces, err := net.Interfaces()
if err != nil {
aghhttp.Error(r, w, http.StatusInternalServerError, "Couldn't get interfaces: %s", err)
return
}
for _, iface := range ifaces {
if iface.Flags&net.FlagLoopback != 0 {
// It's a loopback, skip it.
continue
}
if iface.Flags&net.FlagBroadcast == 0 {
// This interface doesn't support broadcast, skip it.
continue
}
jsonIface, iErr := newNetInterfaceJSON(iface)
if iErr != nil {
aghhttp.Error(r, w, http.StatusInternalServerError, "%s", iErr)
return
}
if jsonIface != nil {
resp[iface.Name] = jsonIface
}
}
aghhttp.WriteJSONResponseOK(w, r, resp)
}
// newNetInterfaceJSON creates a JSON object from a [net.Interface] iface.
func newNetInterfaceJSON(iface net.Interface) (out *netInterfaceJSON, err error) {
addrs, err := iface.Addrs()
if err != nil {
return nil, fmt.Errorf(
"failed to get addresses for interface %s: %w",
iface.Name,
err,
)
}
out = &netInterfaceJSON{
Name: iface.Name,
HardwareAddr: iface.HardwareAddr.String(),
}
if iface.Flags != 0 {
out.Flags = iface.Flags.String()
}
// We don't want link-local addresses in JSON, so skip them.
for _, addr := range addrs {
ipNet, ok := addr.(*net.IPNet)
if !ok {
// Not an IPNet, should not happen.
return nil, fmt.Errorf("got iface.Addrs() element %[1]s that is not"+
" net.IPNet, it is %[1]T", addr)
}
// Ignore link-local.
//
// TODO(e.burkov): Try to listen DHCP on LLA as well.
if ipNet.IP.IsLinkLocalUnicast() {
continue
}
vAddr, iErr := netutil.IPToAddrNoMapped(ipNet.IP)
if iErr != nil {
// Not an IPNet, should not happen.
return nil, fmt.Errorf("failed to convert IP address %[1]s: %w", addr, iErr)
}
if vAddr.Is4() {
out.Addrs4 = append(out.Addrs4, vAddr)
} else {
out.Addrs6 = append(out.Addrs6, vAddr)
}
}
if len(out.Addrs4)+len(out.Addrs6) == 0 {
return nil, nil
}
out.GatewayIP = aghnet.GatewayIP(iface.Name)
return out, nil
}
// dhcpSearchOtherResult contains information about other DHCP server for
// specific network interface.
type dhcpSearchOtherResult struct {
Found string `json:"found,omitempty"`
Error string `json:"error,omitempty"`
}
// dhcpStaticIPStatus contains information about static IP address for DHCP
// server.
type dhcpStaticIPStatus struct {
Static string `json:"static"`
IP string `json:"ip,omitempty"`
Error string `json:"error,omitempty"`
}
// dhcpSearchV4Result contains information about DHCPv4 server for specific
// network interface.
type dhcpSearchV4Result struct {
OtherServer dhcpSearchOtherResult `json:"other_server"`
StaticIP dhcpStaticIPStatus `json:"static_ip"`
}
// dhcpSearchV6Result contains information about DHCPv6 server for specific
// network interface.
type dhcpSearchV6Result struct {
OtherServer dhcpSearchOtherResult `json:"other_server"`
}
// dhcpSearchResult is a response for /control/dhcp/find_active_dhcp endpoint.
type dhcpSearchResult struct {
V4 dhcpSearchV4Result `json:"v4"`
V6 dhcpSearchV6Result `json:"v6"`
}
// findActiveServerReq is the JSON structure for the request to find active DHCP
// servers.
type findActiveServerReq struct {
Interface string `json:"interface"`
}
// handleDHCPFindActiveServer performs the following tasks:
// 1. searches for another DHCP server in the network;
// 2. check if a static IP is configured for the network interface;
// 3. responds with the results.
func (s *server) handleDHCPFindActiveServer(w http.ResponseWriter, r *http.Request) {
if aghhttp.WriteTextPlainDeprecated(w, r) {
return
}
req := &findActiveServerReq{}
err := json.NewDecoder(r.Body).Decode(req)
if err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "reading req: %s", err)
return
}
ifaceName := req.Interface
if ifaceName == "" {
aghhttp.Error(r, w, http.StatusBadRequest, "empty interface name")
return
}
result := &dhcpSearchResult{
V4: dhcpSearchV4Result{
OtherServer: dhcpSearchOtherResult{
Found: "no",
},
StaticIP: dhcpStaticIPStatus{
Static: "yes",
},
},
V6: dhcpSearchV6Result{
OtherServer: dhcpSearchOtherResult{
Found: "no",
},
},
}
if isStaticIP, serr := aghnet.IfaceHasStaticIP(ifaceName); serr != nil {
result.V4.StaticIP.Static = "error"
result.V4.StaticIP.Error = serr.Error()
} else if !isStaticIP {
result.V4.StaticIP.Static = "no"
// TODO(e.burkov): The returned IP should only be of version 4.
result.V4.StaticIP.IP = aghnet.GetSubnet(ifaceName).String()
}
setOtherDHCPResult(ifaceName, result)
aghhttp.WriteJSONResponseOK(w, r, result)
}
// setOtherDHCPResult sets the results of the check for another DHCP server in
// result.
func setOtherDHCPResult(ifaceName string, result *dhcpSearchResult) {
found4, found6, err4, err6 := aghnet.CheckOtherDHCP(ifaceName)
if err4 != nil {
result.V4.OtherServer.Found = "error"
result.V4.OtherServer.Error = err4.Error()
} else if found4 {
result.V4.OtherServer.Found = "yes"
}
if err6 != nil {
result.V6.OtherServer.Found = "error"
result.V6.OtherServer.Error = err6.Error()
} else if found6 {
result.V6.OtherServer.Found = "yes"
}
}
// parseLease parses a lease from r. If there is no error returns DHCPServer
// and *Lease. r must be non-nil.
func (s *server) parseLease(r io.Reader) (srv DHCPServer, lease *Lease, err error) {
l := &leaseStatic{}
err = json.NewDecoder(r).Decode(l)
if err != nil {
return nil, nil, fmt.Errorf("decoding json: %w", err)
}
if !l.IP.IsValid() {
return nil, nil, errors.Error("invalid ip")
}
l.IP = l.IP.Unmap()
lease, err = l.toLease()
if err != nil {
return nil, nil, fmt.Errorf("parsing: %w", err)
}
if lease.IP.Is4() {
srv = s.srv4
} else {
srv = s.srv6
}
return srv, lease, nil
}
// handleDHCPAddStaticLease is the handler for the POST
// /control/dhcp/add_static_lease HTTP API.
func (s *server) handleDHCPAddStaticLease(w http.ResponseWriter, r *http.Request) {
srv, lease, err := s.parseLease(r.Body)
if err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "%s", err)
return
}
if err = srv.AddStaticLease(lease); err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "%s", err)
}
}
// handleDHCPRemoveStaticLease is the handler for the POST
// /control/dhcp/remove_static_lease HTTP API.
func (s *server) handleDHCPRemoveStaticLease(w http.ResponseWriter, r *http.Request) {
srv, lease, err := s.parseLease(r.Body)
if err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "%s", err)
return
}
if err = srv.RemoveStaticLease(lease); err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "%s", err)
}
}
// handleDHCPUpdateStaticLease is the handler for the POST
// /control/dhcp/update_static_lease HTTP API.
func (s *server) handleDHCPUpdateStaticLease(w http.ResponseWriter, r *http.Request) {
srv, lease, err := s.parseLease(r.Body)
if err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "%s", err)
return
}
if err = srv.UpdateStaticLease(lease); err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "%s", err)
}
}
func (s *server) handleReset(w http.ResponseWriter, r *http.Request) {
err := s.Stop()
if err != nil {
aghhttp.Error(r, w, http.StatusInternalServerError, "stopping dhcp: %s", err)
return
}
err = os.Remove(s.conf.dbFilePath)
if err != nil && !errors.Is(err, os.ErrNotExist) {
log.Error("dhcp: removing db: %s", err)
}
s.conf = &ServerConfig{
ConfigModified: s.conf.ConfigModified,
HTTPRegister: s.conf.HTTPRegister,
LocalDomainName: s.conf.LocalDomainName,
DataDir: s.conf.DataDir,
dbFilePath: s.conf.dbFilePath,
}
v4conf := &V4ServerConf{
LeaseDuration: DefaultDHCPLeaseTTL,
ICMPTimeout: DefaultDHCPTimeoutICMP,
notify: s.onNotify,
}
s.srv4, _ = v4Create(v4conf)
v6conf := V6ServerConf{
LeaseDuration: DefaultDHCPLeaseTTL,
notify: s.onNotify,
}
s.srv6, _ = v6Create(v6conf)
s.conf.ConfigModified()
}
func (s *server) handleResetLeases(w http.ResponseWriter, r *http.Request) {
err := s.resetLeases()
if err != nil {
msg := "resetting leases: %s"
aghhttp.Error(r, w, http.StatusInternalServerError, msg, err)
return
}
}
func (s *server) registerHandlers() {
if s.conf.HTTPRegister == nil {
return
}
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/update_static_lease", s.handleDHCPUpdateStaticLease)
s.conf.HTTPRegister(http.MethodPost, "/control/dhcp/reset", s.handleReset)
s.conf.HTTPRegister(http.MethodPost, "/control/dhcp/reset_leases", s.handleResetLeases)
}