AdGuardHome/dhcp.go

461 lines
10 KiB
Go

package main
import (
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"net"
"net/http"
"os/exec"
"runtime"
"strings"
"time"
"github.com/AdguardTeam/AdGuardHome/dhcpd"
"github.com/AdguardTeam/golibs/file"
"github.com/AdguardTeam/golibs/log"
"github.com/joomcode/errorx"
)
var dhcpServer = dhcpd.Server{}
// []dhcpd.Lease -> JSON
func convertLeases(inputLeases []dhcpd.Lease, includeExpires bool) []map[string]string {
leases := []map[string]string{}
for _, l := range inputLeases {
lease := map[string]string{
"mac": l.HWAddr.String(),
"ip": l.IP.String(),
"hostname": l.Hostname,
}
if includeExpires {
lease["expires"] = l.Expiry.Format(time.RFC3339)
}
leases = append(leases, lease)
}
return leases
}
func handleDHCPStatus(w http.ResponseWriter, r *http.Request) {
log.Tracef("%s %v", r.Method, r.URL)
leases := convertLeases(dhcpServer.Leases(), true)
staticLeases := convertLeases(dhcpServer.StaticLeases(), false)
status := map[string]interface{}{
"config": config.DHCP,
"leases": leases,
"static_leases": staticLeases,
}
w.Header().Set("Content-Type", "application/json")
err := json.NewEncoder(w).Encode(status)
if err != nil {
httpError(w, http.StatusInternalServerError, "Unable to marshal DHCP status json: %s", err)
return
}
}
type leaseJSON struct {
HWAddr string `json:"mac"`
IP string `json:"ip"`
Hostname string `json:"hostname"`
}
type dhcpServerConfigJSON struct {
dhcpd.ServerConfig `json:",inline"`
StaticLeases []leaseJSON `json:"static_leases"`
}
func handleDHCPSetConfig(w http.ResponseWriter, r *http.Request) {
log.Tracef("%s %v", r.Method, r.URL)
newconfig := dhcpServerConfigJSON{}
err := json.NewDecoder(r.Body).Decode(&newconfig)
if err != nil {
httpError(w, http.StatusBadRequest, "Failed to parse new DHCP config json: %s", err)
return
}
err = dhcpServer.CheckConfig(newconfig.ServerConfig)
if err != nil {
httpError(w, http.StatusBadRequest, "Invalid DHCP configuration: %s", err)
return
}
err = dhcpServer.Stop()
if err != nil {
log.Error("failed to stop the DHCP server: %s", err)
}
err = dhcpServer.Init(newconfig.ServerConfig)
if err != nil {
httpError(w, http.StatusBadRequest, "Invalid DHCP configuration: %s", err)
return
}
if newconfig.Enabled {
staticIP, err := hasStaticIP(newconfig.InterfaceName)
if !staticIP && err == nil {
err = setStaticIP(newconfig.InterfaceName)
if err != nil {
httpError(w, http.StatusInternalServerError, "Failed to configure static IP: %s", err)
return
}
}
err = dhcpServer.Start()
if err != nil {
httpError(w, http.StatusBadRequest, "Failed to start DHCP server: %s", err)
return
}
}
config.DHCP = newconfig.ServerConfig
httpUpdateConfigReloadDNSReturnOK(w, r)
}
func handleDHCPInterfaces(w http.ResponseWriter, r *http.Request) {
log.Tracef("%s %v", r.Method, r.URL)
response := map[string]interface{}{}
ifaces, err := getValidNetInterfaces()
if err != nil {
httpError(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
}
addrs, err := iface.Addrs()
if err != nil {
httpError(w, http.StatusInternalServerError, "Failed to get addresses for interface %s: %s", iface.Name, err)
return
}
jsonIface := netInterface{
Name: iface.Name,
MTU: iface.MTU,
HardwareAddr: iface.HardwareAddr.String(),
}
if iface.Flags != 0 {
jsonIface.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
httpError(w, http.StatusInternalServerError, "SHOULD NOT HAPPEN: got iface.Addrs() element %s that is not net.IPNet, it is %T", addr, addr)
return
}
// ignore link-local
if ipnet.IP.IsLinkLocalUnicast() {
continue
}
jsonIface.Addresses = append(jsonIface.Addresses, ipnet.IP.String())
}
if len(jsonIface.Addresses) != 0 {
response[iface.Name] = jsonIface
}
}
err = json.NewEncoder(w).Encode(response)
if err != nil {
httpError(w, http.StatusInternalServerError, "Failed to marshal json with available interfaces: %s", err)
return
}
}
// Perform the following tasks:
// . Search for another DHCP server running
// . Check if a static IP is configured for the network interface
// Respond with results
func handleDHCPFindActiveServer(w http.ResponseWriter, r *http.Request) {
log.Tracef("%s %v", r.Method, r.URL)
body, err := ioutil.ReadAll(r.Body)
if err != nil {
errorText := fmt.Sprintf("failed to read request body: %s", err)
log.Error(errorText)
http.Error(w, errorText, http.StatusBadRequest)
return
}
interfaceName := strings.TrimSpace(string(body))
if interfaceName == "" {
errorText := fmt.Sprintf("empty interface name specified")
log.Error(errorText)
http.Error(w, errorText, http.StatusBadRequest)
return
}
found, err := dhcpd.CheckIfOtherDHCPServersPresent(interfaceName)
othSrv := map[string]interface{}{}
foundVal := "no"
if found {
foundVal = "yes"
} else if err != nil {
foundVal = "error"
othSrv["error"] = err.Error()
}
othSrv["found"] = foundVal
staticIP := map[string]interface{}{}
isStaticIP, err := hasStaticIP(interfaceName)
staticIPStatus := "yes"
if err != nil {
staticIPStatus = "error"
staticIP["error"] = err.Error()
} else if !isStaticIP {
staticIPStatus = "no"
staticIP["ip"] = getFullIP(interfaceName)
}
staticIP["static"] = staticIPStatus
result := map[string]interface{}{}
result["other_server"] = othSrv
result["static_ip"] = staticIP
w.Header().Set("Content-Type", "application/json")
err = json.NewEncoder(w).Encode(result)
if err != nil {
httpError(w, http.StatusInternalServerError, "Failed to marshal DHCP found json: %s", err)
return
}
}
// Check if network interface has a static IP configured
func hasStaticIP(ifaceName string) (bool, error) {
if runtime.GOOS == "windows" {
return false, errors.New("Can't detect static IP: not supported on Windows")
}
body, err := ioutil.ReadFile("/etc/dhcpcd.conf")
if err != nil {
return false, err
}
lines := strings.Split(string(body), "\n")
nameLine := fmt.Sprintf("interface %s", ifaceName)
withinInterfaceCtx := false
for _, line := range lines {
line = strings.TrimSpace(line)
if withinInterfaceCtx && len(line) == 0 {
// an empty line resets our state
withinInterfaceCtx = false
}
if len(line) == 0 || line[0] == '#' {
continue
}
line = strings.TrimSpace(line)
if !withinInterfaceCtx {
if line == nameLine {
// we found our interface
withinInterfaceCtx = true
}
} else {
if strings.HasPrefix(line, "interface ") {
// we found another interface - reset our state
withinInterfaceCtx = false
continue
}
if strings.HasPrefix(line, "static ip_address=") {
return true, nil
}
}
}
return false, nil
}
// Get IP address with netmask
func getFullIP(ifaceName string) string {
cmd := exec.Command("ip", "-oneline", "-family", "inet", "address", "show", ifaceName)
log.Tracef("executing %s %v", cmd.Path, cmd.Args)
d, err := cmd.Output()
if err != nil || cmd.ProcessState.ExitCode() != 0 {
return ""
}
fields := strings.Fields(string(d))
if len(fields) < 4 {
return ""
}
_, _, err = net.ParseCIDR(fields[3])
if err != nil {
return ""
}
return fields[3]
}
// Get gateway IP address
func getGatewayIP(ifaceName string) string {
cmd := exec.Command("ip", "route", "show", "dev", ifaceName)
log.Tracef("executing %s %v", cmd.Path, cmd.Args)
d, err := cmd.Output()
if err != nil || cmd.ProcessState.ExitCode() != 0 {
return ""
}
fields := strings.Fields(string(d))
if len(fields) < 3 || fields[0] != "default" {
return ""
}
ip := net.ParseIP(fields[2])
if ip == nil {
return ""
}
return fields[2]
}
// Set a static IP for network interface
func setStaticIP(ifaceName string) error {
ip := getFullIP(ifaceName)
if len(ip) == 0 {
return errors.New("Can't get IP address")
}
body, err := ioutil.ReadFile("/etc/dhcpcd.conf")
if err != nil {
return err
}
ip4, _, err := net.ParseCIDR(ip)
if err != nil {
return err
}
add := fmt.Sprintf("\ninterface %s\nstatic ip_address=%s\n",
ifaceName, ip)
body = append(body, []byte(add)...)
gatewayIP := getGatewayIP(ifaceName)
if len(gatewayIP) != 0 {
add = fmt.Sprintf("static routers=%s\n",
gatewayIP)
body = append(body, []byte(add)...)
}
add = fmt.Sprintf("static domain_name_servers=%s\n\n",
ip4)
body = append(body, []byte(add)...)
err = file.SafeWrite("/etc/dhcpcd.conf", body)
if err != nil {
return err
}
return nil
}
func handleDHCPAddStaticLease(w http.ResponseWriter, r *http.Request) {
log.Tracef("%s %v", r.Method, r.URL)
lj := leaseJSON{}
err := json.NewDecoder(r.Body).Decode(&lj)
if err != nil {
httpError(w, http.StatusBadRequest, "json.Decode: %s", err)
return
}
ip := parseIPv4(lj.IP)
if ip == nil {
httpError(w, http.StatusBadRequest, "invalid IP")
return
}
mac, _ := net.ParseMAC(lj.HWAddr)
lease := dhcpd.Lease{
IP: ip,
HWAddr: mac,
Hostname: lj.Hostname,
}
err = dhcpServer.AddStaticLease(lease)
if err != nil {
httpError(w, http.StatusBadRequest, "%s", err)
return
}
returnOK(w)
}
func handleDHCPRemoveStaticLease(w http.ResponseWriter, r *http.Request) {
log.Tracef("%s %v", r.Method, r.URL)
lj := leaseJSON{}
err := json.NewDecoder(r.Body).Decode(&lj)
if err != nil {
httpError(w, http.StatusBadRequest, "json.Decode: %s", err)
return
}
ip := parseIPv4(lj.IP)
if ip == nil {
httpError(w, http.StatusBadRequest, "invalid IP")
return
}
mac, _ := net.ParseMAC(lj.HWAddr)
lease := dhcpd.Lease{
IP: ip,
HWAddr: mac,
Hostname: lj.Hostname,
}
err = dhcpServer.RemoveStaticLease(lease)
if err != nil {
httpError(w, http.StatusBadRequest, "%s", err)
return
}
returnOK(w)
}
func startDHCPServer() error {
if !config.DHCP.Enabled {
// not enabled, don't do anything
return nil
}
err := dhcpServer.Init(config.DHCP)
if err != nil {
return errorx.Decorate(err, "Couldn't init DHCP server")
}
err = dhcpServer.Start()
if err != nil {
return errorx.Decorate(err, "Couldn't start DHCP server")
}
return nil
}
func stopDHCPServer() error {
if !config.DHCP.Enabled {
return nil
}
err := dhcpServer.Stop()
if err != nil {
return errorx.Decorate(err, "Couldn't stop DHCP server")
}
return nil
}