136 lines
3.7 KiB
Go
136 lines
3.7 KiB
Go
package dhcpsvc
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import (
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"fmt"
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"net/netip"
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"time"
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"github.com/AdguardTeam/golibs/log"
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"github.com/google/gopacket/layers"
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"golang.org/x/exp/slices"
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)
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// IPv6Config is the interface-specific configuration for DHCPv6.
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type IPv6Config struct {
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// RangeStart is the first address in the range to assign to DHCP clients.
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RangeStart netip.Addr
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// Options is the list of DHCP options to send to DHCP clients. The options
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// with zero length are treated as deletions of the corresponding options,
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// either implicit or explicit.
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Options layers.DHCPv6Options
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// LeaseDuration is the TTL of a DHCP lease.
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LeaseDuration time.Duration
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// RASlaacOnly defines whether the DHCP clients should only use SLAAC for
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// address assignment.
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RASLAACOnly bool
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// RAAllowSlaac defines whether the DHCP clients may use SLAAC for address
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// assignment.
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RAAllowSLAAC bool
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// Enabled is the state of the DHCPv6 service, whether it is enabled or not
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// on the specific interface.
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Enabled bool
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}
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// validate returns an error in conf if any.
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func (conf *IPv6Config) validate() (err error) {
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switch {
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case conf == nil:
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return errNilConfig
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case !conf.Enabled:
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return nil
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case !conf.RangeStart.Is6():
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return fmt.Errorf("range start %s should be a valid ipv6", conf.RangeStart)
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case conf.LeaseDuration <= 0:
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return fmt.Errorf("lease duration %s must be positive", conf.LeaseDuration)
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default:
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return nil
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}
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}
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// iface6 is a DHCP interface for IPv6 address family.
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//
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// TODO(e.burkov): Add options.
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type iface6 struct {
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// rangeStart is the first IP address in the range.
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rangeStart netip.Addr
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// name is the name of the interface.
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name string
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// implicitOpts are the DHCPv6 options listed in RFC 8415 (and others) and
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// initialized with default values. It must not have intersections with
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// explicitOpts.
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implicitOpts layers.DHCPv6Options
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// explicitOpts are the user-configured options. It must not have
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// intersections with implicitOpts.
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explicitOpts layers.DHCPv6Options
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// leaseTTL is the time-to-live of dynamic leases on this interface.
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leaseTTL time.Duration
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// raSLAACOnly defines if DHCP should send ICMPv6.RA packets without MO
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// flags.
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raSLAACOnly bool
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// raAllowSLAAC defines if DHCP should send ICMPv6.RA packets with MO flags.
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raAllowSLAAC bool
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}
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// newIface6 creates a new DHCP interface for IPv6 address family with the given
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// configuration.
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//
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// TODO(e.burkov): Validate properly.
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func newIface6(name string, conf *IPv6Config) (i *iface6) {
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if !conf.Enabled {
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return nil
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}
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i = &iface6{
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name: name,
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rangeStart: conf.RangeStart,
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leaseTTL: conf.LeaseDuration,
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raSLAACOnly: conf.RASLAACOnly,
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raAllowSLAAC: conf.RAAllowSLAAC,
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}
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i.implicitOpts, i.explicitOpts = conf.options()
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return i
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}
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// options returns the implicit and explicit options for the interface. The two
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// lists are disjoint and the implicit options are initialized with default
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// values.
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//
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// TODO(e.burkov): Add implicit options according to RFC.
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func (conf *IPv6Config) options() (implicit, explicit layers.DHCPv6Options) {
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// Set default values of host configuration parameters listed in RFC 8415.
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implicit = layers.DHCPv6Options{}
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slices.SortFunc(implicit, compareV6OptionCodes)
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// Set values for explicitly configured options.
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for _, exp := range conf.Options {
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i, found := slices.BinarySearchFunc(implicit, exp, compareV6OptionCodes)
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if found {
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implicit = slices.Delete(implicit, i, i+1)
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}
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explicit = append(explicit, exp)
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}
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log.Debug("dhcpsvc: v6: implicit options: %s", implicit)
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log.Debug("dhcpsvc: v6: explicit options: %s", explicit)
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return implicit, explicit
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}
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// compareV6OptionCodes compares option codes of a and b.
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func compareV6OptionCodes(a, b layers.DHCPv6Option) (res int) {
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return int(a.Code) - int(b.Code)
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}
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