Pull request: all: imp dhcp host normalization, validation
Updates #2952. Squashed commit of the following: commit 45afcab5d33c1ec8176c0ad05423288c8770b772 Author: Ainar Garipov <A.Garipov@AdGuard.COM> Date: Tue Apr 20 15:02:34 2021 +0300 all: imp docs commit d844ce1e2bb0b92a892119161774ec95f3e59711 Author: Ainar Garipov <A.Garipov@AdGuard.COM> Date: Tue Apr 20 14:57:49 2021 +0300 all: more code imp commit eef08cb69015ead0ffaef866e12a2c6556786d37 Author: Ainar Garipov <A.Garipov@AdGuard.COM> Date: Tue Apr 20 14:52:33 2021 +0300 all: imp code, docs commit 20748f20ab9fcc410b11daf0e23eaf156dcdc7cd Author: Ainar Garipov <A.Garipov@AdGuard.COM> Date: Tue Apr 20 14:30:57 2021 +0300 all: imp dhcp host normalization, validation
This commit is contained in:
Ainar Garipov
parent
cd9eb3b3e4
commit
71030bafd8
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@ -15,6 +15,7 @@ and this project adheres to
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### Added
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- Hostname uniqueness validation in the DHCP server ([#2952]).
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- Hostname generating for DHCP clients which don't provide their own ([#2723]).
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- New flag `--no-etc-hosts` to disable client domain name lookups in the
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operating system's /etc/hosts files ([#1947]).
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@ -0,0 +1,71 @@
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package aghstrings
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// unit is a convenient alias for struct{}
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type unit = struct{}
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// Set is a set of strings.
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type Set struct {
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m map[string]unit
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}
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// NewSet returns a new string set containing strs.
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func NewSet(strs ...string) (set *Set) {
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set = &Set{
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m: make(map[string]unit, len(strs)),
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}
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for _, s := range strs {
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set.Add(s)
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}
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return set
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}
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// Add adds s to the set. Add panics if the set is a nil set, just like a nil
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// map does.
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func (set *Set) Add(s string) {
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set.m[s] = unit{}
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}
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// Del deletes s from the set. Calling Del on a nil set has no effect, just
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// like delete on an empty map doesn't.
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func (set *Set) Del(s string) {
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if set != nil {
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delete(set.m, s)
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}
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}
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// Has returns true if s is in the set. Calling Has on a nil set returns false,
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// just like indexing on an empty map does.
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func (set *Set) Has(s string) (ok bool) {
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if set != nil {
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_, ok = set.m[s]
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}
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return ok
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}
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// Len returns the length of the set. A nil set has a length of zero, just like
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// an empty map.
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func (set *Set) Len() (n int) {
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if set == nil {
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return 0
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}
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return len(set.m)
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}
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// Values returns all values in the set. The order of the values is undefined.
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// Values returns nil if the set is nil.
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func (set *Set) Values() (strs []string) {
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if set == nil {
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return nil
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}
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strs = make([]string, 0, len(set.m))
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for s := range set.m {
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strs = append(strs, s)
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}
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return strs
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}
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@ -0,0 +1,56 @@
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package aghstrings
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import (
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"testing"
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"github.com/stretchr/testify/assert"
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)
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func TestSet(t *testing.T) {
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const s = "a"
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t.Run("nil", func(t *testing.T) {
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var set *Set
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assert.NotPanics(t, func() {
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set.Del(s)
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})
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assert.NotPanics(t, func() {
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assert.False(t, set.Has(s))
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})
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assert.NotPanics(t, func() {
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assert.Equal(t, 0, set.Len())
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})
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assert.NotPanics(t, func() {
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assert.Nil(t, set.Values())
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})
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assert.Panics(t, func() {
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set.Add(s)
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})
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})
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t.Run("non_nil", func(t *testing.T) {
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set := NewSet()
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assert.Equal(t, 0, set.Len())
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ok := set.Has(s)
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assert.False(t, ok)
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set.Add(s)
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ok = set.Has(s)
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assert.True(t, ok)
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assert.Equal(t, []string{s}, set.Values())
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set.Del(s)
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ok = set.Has(s)
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assert.False(t, ok)
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set = NewSet(s)
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assert.Equal(t, 1, set.Len())
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})
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}
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@ -110,3 +110,8 @@ func (r *ipRange) offset(ip net.IP) (offset uint64, ok bool) {
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// construction.
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return offsetInt.Uint64(), true
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}
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// String implements the fmt.Stringer interface for *ipRange.
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func (r *ipRange) String() (s string) {
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return fmt.Sprintf("%s-%s", r.start, r.end)
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}
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@ -64,9 +64,12 @@ type V4ServerConf struct {
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leaseTime time.Duration // the time during which a dynamic lease is considered valid
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dnsIPAddrs []net.IP // IPv4 addresses to return to DHCP clients as DNS server addresses
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routerIP net.IP // value for Option Router
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subnetMask net.IPMask // value for Option SubnetMask
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options []dhcpOption
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// subnet contains the DHCP server's subnet. The IP is the IP of the
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// gateway.
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subnet *net.IPNet
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options []dhcpOption
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// notify is a way to signal to other components that leases have
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// change. notify must be called outside of locked sections, since the
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@ -12,6 +12,7 @@ import (
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"github.com/AdguardTeam/AdGuardHome/internal/agherr"
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"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
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"github.com/AdguardTeam/AdGuardHome/internal/aghstrings"
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"github.com/AdguardTeam/golibs/log"
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"github.com/go-ping/ping"
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"github.com/insomniacslk/dhcp/dhcpv4"
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@ -29,6 +30,9 @@ type v4Server struct {
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// leased.
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leasedOffsets *bitSet
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// leaseHosts is the set of all hostnames of all known DHCP clients.
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leaseHosts *aghstrings.Set
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// leases contains all dynamic and static leases.
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leases []*Lease
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@ -49,22 +53,16 @@ func (s *v4Server) WriteDiskConfig6(c *V6ServerConf) {
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func (s *v4Server) ResetLeases(leases []*Lease) {
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s.leases = nil
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r := s.conf.ipRange
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for _, l := range leases {
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if !l.IsStatic() && !r.contains(l.IP) {
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log.Debug(
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"dhcpv4: skipping lease %s (%s): not within current ip range",
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l.IP,
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l.HWAddr,
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)
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continue
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}
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err := s.addLease(l)
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if err != nil {
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// TODO(a.garipov): Better error handling.
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log.Error("dhcpv4: adding a lease for %s (%s): %s", l.IP, l.HWAddr, err)
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log.Error(
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"dhcpv4: reset: re-adding a lease for %s (%s): %s",
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l.IP,
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l.HWAddr,
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err,
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)
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continue
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}
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@ -174,17 +172,14 @@ func (s *v4Server) rmLeaseByIndex(i int) {
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l := s.leases[i]
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s.leases = append(s.leases[:i], s.leases[i+1:]...)
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n = len(s.leases)
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if n > 0 {
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s.leases = s.leases[:n-1]
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}
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r := s.conf.ipRange
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offset, ok := r.offset(l.IP)
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if ok {
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s.leasedOffsets.set(offset, false)
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}
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s.leaseHosts.Del(l.Hostname)
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log.Debug("dhcpv4: removed lease %s (%s)", l.IP, l.HWAddr)
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}
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@ -220,13 +215,8 @@ func (s *v4Server) rmDynamicLease(lease *Lease) (err error) {
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}
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func (s *v4Server) addStaticLease(l *Lease) (err error) {
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subnet := &net.IPNet{
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IP: s.conf.routerIP,
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Mask: s.conf.subnetMask,
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}
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if !subnet.Contains(l.IP) {
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return fmt.Errorf("subnet %s does not contain the ip %q", subnet, l.IP)
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if sn := s.conf.subnet; !sn.Contains(l.IP) {
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return fmt.Errorf("subnet %s does not contain the ip %q", sn, l.IP)
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}
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s.leases = append(s.leases, l)
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@ -237,6 +227,8 @@ func (s *v4Server) addStaticLease(l *Lease) (err error) {
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s.leasedOffsets.set(offset, true)
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}
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s.leaseHosts.Add(l.Hostname)
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return nil
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}
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@ -248,6 +240,7 @@ func (s *v4Server) addDynamicLease(l *Lease) (err error) {
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}
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s.leases = append(s.leases, l)
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s.leaseHosts.Add(l.Hostname)
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s.leasedOffsets.set(offset, true)
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return nil
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@ -255,6 +248,11 @@ func (s *v4Server) addDynamicLease(l *Lease) (err error) {
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// addLease adds a dynamic or static lease.
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func (s *v4Server) addLease(l *Lease) (err error) {
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err = s.validateLease(l)
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if err != nil {
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return err
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}
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if l.IsStatic() {
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return s.addStaticLease(l)
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}
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@ -291,13 +289,13 @@ func (s *v4Server) AddStaticLease(l Lease) (err error) {
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return fmt.Errorf("invalid ip %q, only ipv4 is supported", l.IP)
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}
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err = aghnet.ValidateHardwareAddress(l.HWAddr)
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if err != nil {
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return fmt.Errorf("validating lease: %w", err)
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}
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l.Expiry = time.Unix(leaseExpireStatic, 0)
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l.Hostname, err = normalizeHostname(l.Hostname)
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if err != nil {
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return err
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}
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// Perform the following actions in an anonymous function to make sure
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// that the lock gets unlocked before the notification step.
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func() {
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@ -564,7 +562,8 @@ func normalizeHostname(name string) (norm string, err error) {
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return "", nil
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}
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parts := strings.FieldsFunc(name, func(c rune) (ok bool) {
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norm = strings.ToLower(name)
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parts := strings.FieldsFunc(norm, func(c rune) (ok bool) {
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return c != '.' && !aghnet.IsValidHostOuterRune(c)
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})
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@ -580,19 +579,50 @@ func normalizeHostname(name string) (norm string, err error) {
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// validateHostname validates a hostname sent by the client.
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func (s *v4Server) validateHostname(name string) (err error) {
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defer agherr.Annotate("validating hostname: %s", &err)
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if name == "" {
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return nil
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}
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err = aghnet.ValidateDomainName(name)
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if err != nil {
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return fmt.Errorf("validating hostname: %w", err)
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return err
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}
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// TODO(a.garipov): Add client hostname uniqueness validation either
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// here or into method processRequest. This is not as easy as it might
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// look like, because the process of adding and releasing a lease is
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// currently non-straightforward.
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if s.leaseHosts.Has(name) {
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return agherr.Error("hostname exists")
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}
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return nil
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}
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// validateLease returns an error if the lease is invalid.
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func (s *v4Server) validateLease(l *Lease) (err error) {
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defer agherr.Annotate("validating lease: %s", &err)
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if l == nil {
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return agherr.Error("lease is nil")
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}
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err = aghnet.ValidateHardwareAddress(l.HWAddr)
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if err != nil {
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return err
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}
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err = s.validateHostname(l.Hostname)
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if err != nil {
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return err
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}
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if sn := s.conf.subnet; !sn.Contains(l.IP) {
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return fmt.Errorf("subnet %s does not contain the ip %q", sn, l.IP)
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}
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r := s.conf.ipRange
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if !l.IsStatic() && !r.contains(l.IP) {
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return fmt.Errorf("dynamic lease range %s does not contain the ip %q", r, l.IP)
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}
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return nil
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}
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@ -655,15 +685,27 @@ func (s *v4Server) processRequest(req, resp *dhcpv4.DHCPv4) (lease *Lease, ok bo
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// Go on and assign a hostname made from the IP.
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}
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if hostname != "" && cliHostname != hostname {
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log.Debug("dhcpv4: normalized hostname %q into %q", cliHostname, hostname)
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}
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if hostname != "" {
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if cliHostname != hostname {
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log.Debug(
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"dhcpv4: normalized hostname %q into %q",
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cliHostname,
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hostname,
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)
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}
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err = s.validateHostname(hostname)
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if err != nil {
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log.Error("dhcpv4: validating hostname for %s: %s", mac, err)
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if lease.Hostname != hostname {
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// Either a new lease or an old lease with a new
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// hostname, so validate.
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err = s.validateHostname(hostname)
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if err != nil {
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log.Error("dhcpv4: validating %s: %s", mac, err)
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// Go on and assign a hostname made from the IP.
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// Go on and assign a hostname made from
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// the IP below.
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hostname = ""
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}
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}
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}
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if hostname == "" {
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@ -726,8 +768,8 @@ func (s *v4Server) process(req, resp *dhcpv4.DHCPv4) int {
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copy(resp.YourIPAddr, l.IP)
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resp.UpdateOption(dhcpv4.OptIPAddressLeaseTime(s.conf.leaseTime))
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resp.UpdateOption(dhcpv4.OptRouter(s.conf.routerIP))
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resp.UpdateOption(dhcpv4.OptSubnetMask(s.conf.subnetMask))
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resp.UpdateOption(dhcpv4.OptRouter(s.conf.subnet.IP))
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resp.UpdateOption(dhcpv4.OptSubnetMask(s.conf.subnet.Mask))
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resp.UpdateOption(dhcpv4.OptDNS(s.conf.dnsIPAddrs...))
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for _, opt := range s.conf.options {
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|
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@ -855,6 +897,7 @@ func (s *v4Server) Stop() {
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func v4Create(conf V4ServerConf) (srv DHCPServer, err error) {
|
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s := &v4Server{}
|
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s.conf = conf
|
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s.leaseHosts = aghstrings.NewSet()
|
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|
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// TODO(a.garipov): Don't use a disabled server in other places or just
|
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// use an interface.
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|
|
@ -862,7 +905,8 @@ func v4Create(conf V4ServerConf) (srv DHCPServer, err error) {
|
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return s, nil
|
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}
|
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|
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s.conf.routerIP, err = tryTo4(s.conf.GatewayIP)
|
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var routerIP net.IP
|
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routerIP, err = tryTo4(s.conf.GatewayIP)
|
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if err != nil {
|
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return s, fmt.Errorf("dhcpv4: %w", err)
|
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}
|
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|
|
@ -870,8 +914,14 @@ func v4Create(conf V4ServerConf) (srv DHCPServer, err error) {
|
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if s.conf.SubnetMask == nil {
|
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return s, fmt.Errorf("dhcpv4: invalid subnet mask: %v", s.conf.SubnetMask)
|
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}
|
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s.conf.subnetMask = make([]byte, 4)
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copy(s.conf.subnetMask, s.conf.SubnetMask.To4())
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|
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subnetMask := make([]byte, 4)
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copy(subnetMask, s.conf.SubnetMask.To4())
|
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|
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s.conf.subnet = &net.IPNet{
|
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IP: routerIP,
|
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Mask: subnetMask,
|
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}
|
||||
|
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s.conf.ipRange, err = newIPRange(conf.RangeStart, conf.RangeEnd)
|
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if err != nil {
|
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|
|
|
|||
|
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@ -157,7 +157,7 @@ func TestV4StaticLease_Get(t *testing.T) {
|
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assert.True(t, l.IP.Equal(resp.YourIPAddr))
|
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assert.True(t, s.conf.GatewayIP.Equal(resp.Router()[0]))
|
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assert.True(t, s.conf.GatewayIP.Equal(resp.ServerIdentifier()))
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assert.Equal(t, s.conf.subnetMask, resp.SubnetMask())
|
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assert.Equal(t, s.conf.subnet.Mask, resp.SubnetMask())
|
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assert.Equal(t, s.conf.leaseTime.Seconds(), resp.IPAddressLeaseTime(-1).Seconds())
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})
|
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|
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|
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@ -179,7 +179,7 @@ func TestV4StaticLease_Get(t *testing.T) {
|
|||
assert.True(t, l.IP.Equal(resp.YourIPAddr))
|
||||
assert.True(t, s.conf.GatewayIP.Equal(resp.Router()[0]))
|
||||
assert.True(t, s.conf.GatewayIP.Equal(resp.ServerIdentifier()))
|
||||
assert.Equal(t, s.conf.subnetMask, resp.SubnetMask())
|
||||
assert.Equal(t, s.conf.subnet.Mask, resp.SubnetMask())
|
||||
assert.Equal(t, s.conf.leaseTime.Seconds(), resp.IPAddressLeaseTime(-1).Seconds())
|
||||
})
|
||||
|
||||
|
|
@ -246,7 +246,7 @@ func TestV4DynamicLease_Get(t *testing.T) {
|
|||
|
||||
assert.Equal(t, s.conf.GatewayIP, router[0])
|
||||
|
||||
assert.Equal(t, s.conf.subnetMask, resp.SubnetMask())
|
||||
assert.Equal(t, s.conf.subnet.Mask, resp.SubnetMask())
|
||||
assert.Equal(t, s.conf.leaseTime.Seconds(), resp.IPAddressLeaseTime(-1).Seconds())
|
||||
assert.Equal(t, []byte("012"), resp.Options[uint8(dhcpv4.OptionFQDN)])
|
||||
|
||||
|
|
@ -271,7 +271,7 @@ func TestV4DynamicLease_Get(t *testing.T) {
|
|||
assert.True(t, s.conf.RangeStart.Equal(resp.YourIPAddr))
|
||||
assert.True(t, s.conf.GatewayIP.Equal(resp.Router()[0]))
|
||||
assert.True(t, s.conf.GatewayIP.Equal(resp.ServerIdentifier()))
|
||||
assert.Equal(t, s.conf.subnetMask, resp.SubnetMask())
|
||||
assert.Equal(t, s.conf.subnet.Mask, resp.SubnetMask())
|
||||
assert.Equal(t, s.conf.leaseTime.Seconds(), resp.IPAddressLeaseTime(-1).Seconds())
|
||||
})
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue