AdGuardHome/internal/dhcpd/config.go

244 lines
7.4 KiB
Go

package dhcpd
import (
"fmt"
"net"
"net/netip"
"time"
"github.com/AdguardTeam/AdGuardHome/internal/aghhttp"
"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
"github.com/AdguardTeam/golibs/errors"
)
// ServerConfig is the configuration for the DHCP server. The order of YAML
// fields is important, since the YAML configuration file follows it.
type ServerConfig struct {
// Called when the configuration is changed by HTTP request
ConfigModified func() `yaml:"-"`
// Register an HTTP handler
HTTPRegister aghhttp.RegisterFunc `yaml:"-"`
Enabled bool `yaml:"enabled"`
InterfaceName string `yaml:"interface_name"`
// LocalDomainName is the domain name used for DHCP hosts. For example, a
// DHCP client with the hostname "myhost" can be addressed as "myhost.lan"
// when LocalDomainName is "lan".
//
// TODO(e.burkov): Probably, remove this field. See the TODO on
// [Interface.Enabled].
LocalDomainName string `yaml:"local_domain_name"`
Conf4 V4ServerConf `yaml:"dhcpv4"`
Conf6 V6ServerConf `yaml:"dhcpv6"`
// WorkDir is used to store DHCP leases.
//
// Deprecated: Remove it when migration of DHCP leases will not be needed.
WorkDir string `yaml:"-"`
// DataDir is used to store DHCP leases.
DataDir string `yaml:"-"`
// dbFilePath is the path to the file with stored DHCP leases.
dbFilePath string `yaml:"-"`
}
// DHCPServer - DHCP server interface
type DHCPServer interface {
// ResetLeases resets leases.
ResetLeases(leases []*Lease) (err error)
// GetLeases returns deep clones of the current leases.
GetLeases(flags GetLeasesFlags) (leases []*Lease)
// AddStaticLease - add a static lease
AddStaticLease(l *Lease) (err error)
// RemoveStaticLease - remove a static lease
RemoveStaticLease(l *Lease) (err error)
// FindMACbyIP returns a MAC address by the IP address of its lease, if
// there is one.
FindMACbyIP(ip netip.Addr) (mac net.HardwareAddr)
// HostByIP returns a hostname by the IP address of its lease, if there is
// one.
HostByIP(ip netip.Addr) (host string)
// IPByHost returns an IP address by the hostname of its lease, if there is
// one.
IPByHost(host string) (ip netip.Addr)
// WriteDiskConfig4 - copy disk configuration
WriteDiskConfig4(c *V4ServerConf)
// WriteDiskConfig6 - copy disk configuration
WriteDiskConfig6(c *V6ServerConf)
// Start - start server
Start() (err error)
// Stop - stop server
Stop() (err error)
getLeasesRef() []*Lease
}
// V4ServerConf - server configuration
type V4ServerConf struct {
Enabled bool `yaml:"-" json:"-"`
InterfaceName string `yaml:"-" json:"-"`
GatewayIP netip.Addr `yaml:"gateway_ip" json:"gateway_ip"`
SubnetMask netip.Addr `yaml:"subnet_mask" json:"subnet_mask"`
// broadcastIP is the broadcasting address pre-calculated from the
// configured gateway IP and subnet mask.
broadcastIP netip.Addr
// The first & the last IP address for dynamic leases
// Bytes [0..2] of the last allowed IP address must match the first IP
RangeStart netip.Addr `yaml:"range_start" json:"range_start"`
RangeEnd netip.Addr `yaml:"range_end" json:"range_end"`
LeaseDuration uint32 `yaml:"lease_duration" json:"lease_duration"` // in seconds
// IP conflict detector: time (ms) to wait for ICMP reply
// 0: disable
ICMPTimeout uint32 `yaml:"icmp_timeout_msec" json:"-"`
// Custom Options.
//
// Option with arbitrary hexadecimal data:
// DEC_CODE hex HEX_DATA
// where DEC_CODE is a decimal DHCPv4 option code in range [1..255]
//
// Option with IP data (only 1 IP is supported):
// DEC_CODE ip IP_ADDR
Options []string `yaml:"options" json:"-"`
ipRange *ipRange
leaseTime time.Duration // the time during which a dynamic lease is considered valid
dnsIPAddrs []netip.Addr // IPv4 addresses to return to DHCP clients as DNS server addresses
// subnet contains the DHCP server's subnet. The IP is the IP of the
// gateway.
subnet netip.Prefix
// notify is a way to signal to other components that leases have been
// changed. notify must be called outside of locked sections, since the
// clients might want to get the new data.
//
// TODO(a.garipov): This is utter madness and must be refactored. It just
// begs for deadlock bugs and other nastiness.
notify func(uint32)
}
// errNilConfig is an error returned by validation method if the config is nil.
const errNilConfig errors.Error = "nil config"
// ensureV4 returns an unmapped version of ip. An error is returned if the
// passed ip is not an IPv4.
func ensureV4(ip netip.Addr, kind string) (ip4 netip.Addr, err error) {
ip4 = ip.Unmap()
if !ip4.IsValid() || !ip4.Is4() {
return netip.Addr{}, fmt.Errorf("%v is not an IPv4 %s", ip, kind)
}
return ip4, nil
}
// Validate returns an error if c is not a valid configuration.
//
// TODO(e.burkov): Don't set the config fields when the server itself will stop
// containing the config.
func (c *V4ServerConf) Validate() (err error) {
defer func() { err = errors.Annotate(err, "dhcpv4: %w") }()
if c == nil {
return errNilConfig
}
gatewayIP, err := ensureV4(c.GatewayIP, "address")
if err != nil {
// Don't wrap the error since it's informative enough as is and there is
// an annotation deferred already.
return err
}
subnetMask, err := ensureV4(c.SubnetMask, "subnet mask")
if err != nil {
// Don't wrap the error since it's informative enough as is and there is
// an annotation deferred already.
return err
}
maskLen, _ := net.IPMask(subnetMask.AsSlice()).Size()
c.subnet = netip.PrefixFrom(gatewayIP, maskLen)
c.broadcastIP = aghnet.BroadcastFromPref(c.subnet)
rangeStart, err := ensureV4(c.RangeStart, "address")
if err != nil {
// Don't wrap the error since it's informative enough as is and there is
// an annotation deferred already.
return err
}
rangeEnd, err := ensureV4(c.RangeEnd, "address")
if err != nil {
// Don't wrap the error since it's informative enough as is and there is
// an annotation deferred already.
return err
}
c.ipRange, err = newIPRange(rangeStart.AsSlice(), rangeEnd.AsSlice())
if err != nil {
// Don't wrap the error since it's informative enough as is and there is
// an annotation deferred already.
return err
}
if c.ipRange.contains(gatewayIP.AsSlice()) {
return fmt.Errorf("gateway ip %v in the ip range: %v-%v",
gatewayIP,
c.RangeStart,
c.RangeEnd,
)
}
if !c.subnet.Contains(rangeStart) {
return fmt.Errorf("range start %v is outside network %v",
c.RangeStart,
c.subnet,
)
}
if !c.subnet.Contains(rangeEnd) {
return fmt.Errorf("range end %v is outside network %v",
c.RangeEnd,
c.subnet,
)
}
return nil
}
// V6ServerConf - server configuration
type V6ServerConf struct {
Enabled bool `yaml:"-" json:"-"`
InterfaceName string `yaml:"-" json:"-"`
// The first IP address for dynamic leases
// The last allowed IP address ends with 0xff byte
RangeStart net.IP `yaml:"range_start" json:"range_start"`
LeaseDuration uint32 `yaml:"lease_duration" json:"lease_duration"` // in seconds
RASLAACOnly bool `yaml:"ra_slaac_only" json:"-"` // send ICMPv6.RA packets without MO flags
RAAllowSLAAC bool `yaml:"ra_allow_slaac" json:"-"` // send ICMPv6.RA packets with MO flags
ipStart net.IP // starting IP address for dynamic leases
leaseTime time.Duration // the time during which a dynamic lease is considered valid
dnsIPAddrs []net.IP // IPv6 addresses to return to DHCP clients as DNS server addresses
// Server calls this function when leases data changes
notify func(uint32)
}