462 lines
11 KiB
Go
462 lines
11 KiB
Go
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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/exec"
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"runtime"
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"strings"
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"time"
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"github.com/AdguardTeam/golibs/file"
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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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// []Lease -> JSON
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func convertLeases(inputLeases []Lease, includeExpires bool) []map[string]string {
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leases := []map[string]string{}
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for _, l := range inputLeases {
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lease := map[string]string{
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"mac": l.HWAddr.String(),
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"ip": l.IP.String(),
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"hostname": l.Hostname,
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}
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if includeExpires {
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lease["expires"] = l.Expiry.Format(time.RFC3339)
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}
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leases = append(leases, lease)
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}
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return leases
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}
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func (s *Server) handleDHCPStatus(w http.ResponseWriter, r *http.Request) {
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leases := convertLeases(s.Leases(), true)
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staticLeases := convertLeases(s.StaticLeases(), false)
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status := map[string]interface{}{
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"config": s.conf,
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"leases": leases,
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"static_leases": staticLeases,
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}
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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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type staticLeaseJSON struct {
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HWAddr string `json:"mac"`
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IP string `json:"ip"`
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Hostname string `json:"hostname"`
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}
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type dhcpServerConfigJSON struct {
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ServerConfig `json:",inline"`
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StaticLeases []staticLeaseJSON `json:"static_leases"`
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}
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func (s *Server) handleDHCPSetConfig(w http.ResponseWriter, r *http.Request) {
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newconfig := dhcpServerConfigJSON{}
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err := json.NewDecoder(r.Body).Decode(&newconfig)
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if err != nil {
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httpError(r, w, http.StatusBadRequest, "Failed to parse new DHCP config json: %s", err)
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return
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}
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err = s.CheckConfig(newconfig.ServerConfig)
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if err != nil {
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httpError(r, w, http.StatusBadRequest, "Invalid DHCP configuration: %s", err)
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return
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}
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err = s.Stop()
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if err != nil {
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log.Error("failed to stop the DHCP server: %s", err)
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}
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err = s.Init(newconfig.ServerConfig)
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if err != nil {
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httpError(r, w, http.StatusBadRequest, "Invalid DHCP configuration: %s", err)
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return
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}
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s.conf.ConfigModified()
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if newconfig.Enabled {
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staticIP, err := hasStaticIP(newconfig.InterfaceName)
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if !staticIP && err == nil {
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err = setStaticIP(newconfig.InterfaceName)
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if err != nil {
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httpError(r, w, http.StatusInternalServerError, "Failed to configure static IP: %s", err)
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return
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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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httpError(r, w, http.StatusBadRequest, "Failed to start DHCP server: %s", err)
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return
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}
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}
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}
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type netInterface struct {
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Name string `json:"name"`
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MTU int `json:"mtu"`
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HardwareAddr string `json:"hardware_address"`
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Addresses []string `json:"ip_addresses"`
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Flags string `json:"flags"`
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}
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// getValidNetInterfaces returns interfaces that are eligible for DNS and/or DHCP
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// invalid interface is a ppp interface or the one that doesn't allow broadcasts
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func getValidNetInterfaces() ([]net.Interface, error) {
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ifaces, err := net.Interfaces()
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if err != nil {
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return nil, fmt.Errorf("Couldn't get list of interfaces: %s", err)
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}
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netIfaces := []net.Interface{}
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for i := range ifaces {
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if ifaces[i].Flags&net.FlagPointToPoint != 0 {
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// this interface is ppp, we're not interested in this one
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continue
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}
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iface := ifaces[i]
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netIfaces = append(netIfaces, iface)
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}
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return netIfaces, nil
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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]interface{}{}
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ifaces, err := getValidNetInterfaces()
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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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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 := netInterface{
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Name: iface.Name,
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MTU: iface.MTU,
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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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jsonIface.Addresses = append(jsonIface.Addresses, ipnet.IP.String())
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}
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if len(jsonIface.Addresses) != 0 {
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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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// 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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body, err := ioutil.ReadAll(r.Body)
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if err != nil {
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errorText := fmt.Sprintf("failed to read request body: %s", err)
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log.Error(errorText)
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http.Error(w, errorText, 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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errorText := fmt.Sprintf("empty interface name specified")
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log.Error(errorText)
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http.Error(w, errorText, http.StatusBadRequest)
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return
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}
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found, err := CheckIfOtherDHCPServersPresent(interfaceName)
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othSrv := map[string]interface{}{}
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foundVal := "no"
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if found {
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foundVal = "yes"
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} else if err != nil {
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foundVal = "error"
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othSrv["error"] = err.Error()
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}
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othSrv["found"] = foundVal
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staticIP := map[string]interface{}{}
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isStaticIP, err := hasStaticIP(interfaceName)
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staticIPStatus := "yes"
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if err != nil {
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staticIPStatus = "error"
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staticIP["error"] = err.Error()
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} else if !isStaticIP {
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staticIPStatus = "no"
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staticIP["ip"] = getFullIP(interfaceName)
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}
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staticIP["static"] = staticIPStatus
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result := map[string]interface{}{}
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result["other_server"] = othSrv
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result["static_ip"] = staticIP
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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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// Check if network interface has a static IP configured
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func hasStaticIP(ifaceName string) (bool, error) {
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if runtime.GOOS == "windows" {
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return false, errors.New("Can't detect static IP: not supported on Windows")
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}
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body, err := ioutil.ReadFile("/etc/dhcpcd.conf")
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if err != nil {
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return false, err
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}
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lines := strings.Split(string(body), "\n")
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nameLine := fmt.Sprintf("interface %s", ifaceName)
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withinInterfaceCtx := false
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for _, line := range lines {
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line = strings.TrimSpace(line)
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if withinInterfaceCtx && len(line) == 0 {
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// an empty line resets our state
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withinInterfaceCtx = false
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}
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if len(line) == 0 || line[0] == '#' {
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continue
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}
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line = strings.TrimSpace(line)
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if !withinInterfaceCtx {
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if line == nameLine {
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// we found our interface
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withinInterfaceCtx = true
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}
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} else {
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if strings.HasPrefix(line, "interface ") {
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// we found another interface - reset our state
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withinInterfaceCtx = false
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continue
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}
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if strings.HasPrefix(line, "static ip_address=") {
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return true, nil
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}
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}
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}
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return false, nil
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}
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// Get IP address with netmask
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func getFullIP(ifaceName string) string {
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cmd := exec.Command("ip", "-oneline", "-family", "inet", "address", "show", ifaceName)
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log.Tracef("executing %s %v", cmd.Path, cmd.Args)
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d, err := cmd.Output()
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if err != nil || cmd.ProcessState.ExitCode() != 0 {
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return ""
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}
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fields := strings.Fields(string(d))
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if len(fields) < 4 {
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return ""
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}
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_, _, err = net.ParseCIDR(fields[3])
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if err != nil {
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return ""
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}
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return fields[3]
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}
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// Get gateway IP address
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func getGatewayIP(ifaceName string) string {
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cmd := exec.Command("ip", "route", "show", "dev", ifaceName)
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log.Tracef("executing %s %v", cmd.Path, cmd.Args)
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d, err := cmd.Output()
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if err != nil || cmd.ProcessState.ExitCode() != 0 {
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return ""
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}
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fields := strings.Fields(string(d))
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if len(fields) < 3 || fields[0] != "default" {
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return ""
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}
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ip := net.ParseIP(fields[2])
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if ip == nil {
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return ""
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}
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return fields[2]
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}
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// Set a static IP for network interface
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func setStaticIP(ifaceName string) error {
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ip := getFullIP(ifaceName)
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if len(ip) == 0 {
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return errors.New("Can't get IP address")
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}
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body, err := ioutil.ReadFile("/etc/dhcpcd.conf")
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if err != nil {
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return err
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}
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ip4, _, err := net.ParseCIDR(ip)
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if err != nil {
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return err
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}
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add := fmt.Sprintf("\ninterface %s\nstatic ip_address=%s\n",
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ifaceName, ip)
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body = append(body, []byte(add)...)
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gatewayIP := getGatewayIP(ifaceName)
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if len(gatewayIP) != 0 {
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add = fmt.Sprintf("static routers=%s\n",
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gatewayIP)
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body = append(body, []byte(add)...)
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}
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add = fmt.Sprintf("static domain_name_servers=%s\n\n",
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ip4)
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body = append(body, []byte(add)...)
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err = file.SafeWrite("/etc/dhcpcd.conf", body)
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if err != nil {
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return err
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}
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return nil
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}
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||
|
|
func (s *Server) handleDHCPAddStaticLease(w http.ResponseWriter, r *http.Request) {
|
||
|
|
|
||
|
|
lj := staticLeaseJSON{}
|
||
|
|
err := json.NewDecoder(r.Body).Decode(&lj)
|
||
|
|
if err != nil {
|
||
|
|
httpError(r, w, http.StatusBadRequest, "json.Decode: %s", err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
ip, _ := parseIPv4(lj.IP)
|
||
|
|
if ip == nil {
|
||
|
|
httpError(r, w, http.StatusBadRequest, "invalid IP")
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
mac, _ := net.ParseMAC(lj.HWAddr)
|
||
|
|
|
||
|
|
lease := Lease{
|
||
|
|
IP: ip,
|
||
|
|
HWAddr: mac,
|
||
|
|
Hostname: lj.Hostname,
|
||
|
|
}
|
||
|
|
err = s.AddStaticLease(lease)
|
||
|
|
if err != nil {
|
||
|
|
httpError(r, w, http.StatusBadRequest, "%s", err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (s *Server) handleDHCPRemoveStaticLease(w http.ResponseWriter, r *http.Request) {
|
||
|
|
|
||
|
|
lj := staticLeaseJSON{}
|
||
|
|
err := json.NewDecoder(r.Body).Decode(&lj)
|
||
|
|
if err != nil {
|
||
|
|
httpError(r, w, http.StatusBadRequest, "json.Decode: %s", err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
ip, _ := parseIPv4(lj.IP)
|
||
|
|
if ip == nil {
|
||
|
|
httpError(r, w, http.StatusBadRequest, "invalid IP")
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
mac, _ := net.ParseMAC(lj.HWAddr)
|
||
|
|
|
||
|
|
lease := Lease{
|
||
|
|
IP: ip,
|
||
|
|
HWAddr: mac,
|
||
|
|
Hostname: lj.Hostname,
|
||
|
|
}
|
||
|
|
err = s.RemoveStaticLease(lease)
|
||
|
|
if err != nil {
|
||
|
|
httpError(r, w, http.StatusBadRequest, "%s", err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (s *Server) registerHandlers() {
|
||
|
|
s.conf.HTTPRegister("GET", "/control/dhcp/status", s.handleDHCPStatus)
|
||
|
|
s.conf.HTTPRegister("GET", "/control/dhcp/interfaces", s.handleDHCPInterfaces)
|
||
|
|
s.conf.HTTPRegister("POST", "/control/dhcp/set_config", s.handleDHCPSetConfig)
|
||
|
|
s.conf.HTTPRegister("POST", "/control/dhcp/find_active_dhcp", s.handleDHCPFindActiveServer)
|
||
|
|
s.conf.HTTPRegister("POST", "/control/dhcp/add_static_lease", s.handleDHCPAddStaticLease)
|
||
|
|
s.conf.HTTPRegister("POST", "/control/dhcp/remove_static_lease", s.handleDHCPRemoveStaticLease)
|
||
|
|
}
|