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dhcpd: support to handle DECLINE & RELEASE msg

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This commit is contained in:
nadoo 2021-06-07 19:14:58 +08:00
parent 3092d857ff
commit 41fee381d0
6 changed files with 83 additions and 45 deletions
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3
config/glider.conf.example
View File

@ -233,6 +233,9 @@ dnsminttl=0
# size of CACHE
dnscachesize=4096
# show query log of dns cache
dnscachelog=True
# custom records
dnsrecord=www.example.com/1.2.3.4
dnsrecord=www.example.com/2606:2800:220:1:248:1893:25c8:1946

29
dns/client.go
View File

@ -109,13 +109,19 @@ func (c *Client) handleAnswer(respBytes []byte, clientAddr, dnsServer, network,
}
ips, ttl := c.extractAnswer(resp)
if ttl == 0 { // we got a null result
ttl = 600
if ttl > c.config.MaxTTL {
ttl = c.config.MaxTTL
} else if ttl < c.config.MinTTL {
ttl = c.config.MinTTL
}
if ttl <= 0 { // we got a null result
ttl = 1800
}
c.cache.Set(qKey(resp.Question), valCopy(respBytes), ttl)
log.F("[dns] %s <-> %s(%s) via %s, type: %d, %s: %s",
clientAddr, dnsServer, network, dialerAddr, resp.Question.QTYPE, resp.Question.QNAME, strings.Join(ips, ","))
log.F("[dns] %s <-> %s(%s) via %s, %s/%d: %d %s",
clientAddr, dnsServer, network, dialerAddr, resp.Question.QNAME, resp.Question.QTYPE, ttl, strings.Join(ips, ","))
return nil
}
@ -137,12 +143,6 @@ func (c *Client) extractAnswer(resp *Message) ([]string, int) {
}
}
if ttl > c.config.MaxTTL {
ttl = c.config.MaxTTL
} else if ttl < c.config.MinTTL {
ttl = c.config.MinTTL
}
return ips, ttl
}
@ -277,7 +277,7 @@ func (c *Client) AddHandler(h AnswerHandler) {
func (c *Client) AddRecord(record string) error {
r := strings.Split(record, "/")
domain, ip := r[0], r[1]
m, err := c.MakeResponse(domain, ip)
m, err := c.MakeResponse(domain, ip, uint32(c.config.MaxTTL))
if err != nil {
return err
}
@ -296,10 +296,11 @@ func (c *Client) AddRecord(record string) error {
}
// MakeResponse makes a dns response message for the given domain and ip address.
func (c *Client) MakeResponse(domain string, ip string) (*Message, error) {
// Note: you should make sure ttl > 0.
func (c *Client) MakeResponse(domain, ip string, ttl uint32) (*Message, error) {
ipb := net.ParseIP(ip)
if ipb == nil {
return nil, errors.New("GenResponse: invalid ip format")
return nil, errors.New("MakeResponse: invalid ip format")
}
var rdata []byte
@ -316,7 +317,7 @@ func (c *Client) MakeResponse(domain string, ip string) (*Message, error) {
m := NewMessage(0, Response)
m.SetQuestion(NewQuestion(qtype, domain))
rr := &RR{NAME: domain, TYPE: qtype, CLASS: ClassINET,
TTL: uint32(c.config.MinTTL), RDLENGTH: rdlen, RDATA: rdata}
TTL: ttl, RDLENGTH: rdlen, RDATA: rdata}
m.AddAnswer(rr)
return m, nil

1
go.mod
View File

@ -19,6 +19,7 @@ require (
github.com/xtaci/kcp-go/v5 v5.6.1
golang.org/x/crypto v0.0.0-20210513164829-c07d793c2f9a
golang.org/x/net v0.0.0-20210525063256-abc453219eb5 // indirect
golang.org/x/sys v0.0.0-20210603125802-9665404d3644 // indirect
)
// Replace dependency modules with local developing copy

5
go.sum
View File

@ -154,8 +154,11 @@ golang.org/x/sys v0.0.0-20201009025420-dfb3f7c4e634/go.mod h1:h1NjWce9XRLGQEsW7w
golang.org/x/sys v0.0.0-20201101102859-da207088b7d1/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20210525143221-35b2ab0089ea h1:+WiDlPBBaO+h9vPNZi8uJ3k4BkKQB7Iow3aqwHVA5hI=
golang.org/x/sys v0.0.0-20210525143221-35b2ab0089ea/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20210601080250-7ecdf8ef093b h1:qh4f65QIVFjq9eBURLEYWqaEXmOyqdUyiBSgaXWccWk=
golang.org/x/sys v0.0.0-20210601080250-7ecdf8ef093b/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20210603125802-9665404d3644 h1:CA1DEQ4NdKphKeL70tvsWNdT5oFh1lOjihRcEDROi0I=
golang.org/x/sys v0.0.0-20210603125802-9665404d3644/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1 h1:v+OssWQX+hTHEmOBgwxdZxK4zHq3yOs8F9J7mk0PY8E=
golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

12
service/dhcpd/dhcpd.go
View File

@ -67,14 +67,22 @@ func handleDHCP(serverIP net.IP, mask net.IPMask, pool *Pool) server4.Handler {
switch mt := m.MessageType(); mt {
case dhcpv4.MessageTypeDiscover:
replyType = dhcpv4.MessageTypeOffer
case dhcpv4.MessageTypeRequest:
case dhcpv4.MessageTypeRequest, dhcpv4.MessageTypeInform:
replyType = dhcpv4.MessageTypeAck
case dhcpv4.MessageTypeRelease:
pool.ReleaseIP(m.ClientHWAddr)
log.F("[dpcpd] %v released ip %v", m.ClientHWAddr, m.ClientIPAddr)
return
case dhcpv4.MessageTypeDecline:
pool.ReleaseIP(m.ClientHWAddr)
log.F("[dpcpd] received decline message from %v", m.ClientHWAddr)
return
default:
log.F("[dpcpd] can't handle type %v", mt)
return
}
replyIp, err := pool.AssignIP(m.ClientHWAddr)
replyIp, err := pool.LeaseIP(m.ClientHWAddr)
if err != nil {
log.F("[dpcpd] can not assign IP, error %s", err)
return

78
service/dhcpd/pool.go
View File

@ -5,12 +5,21 @@ import (
"errors"
"math/rand"
"net"
"sync"
"time"
)
// Pool is a dhcp pool.
type Pool struct {
items []*item
mutex sync.RWMutex
lease time.Duration
}
type item struct {
ip net.IP
mac net.HardwareAddr
expire time.Time
}
// NewPool returns a new dhcp ip pool.
@ -26,15 +35,32 @@ func NewPool(lease time.Duration, start, end net.IP) (*Pool, error) {
items := make([]*item, 0, e-s+1)
for n := s; n <= e; n++ {
items = append(items, &item{lease: lease, ip: num2ip(n)})
items = append(items, &item{ip: num2ip(n)})
}
rand.Seed(time.Now().Unix())
return &Pool{items: items}, nil
p := &Pool{items: items, lease: lease}
go func() {
for now := range time.Tick(time.Second) {
p.mutex.Lock()
for i := 0; i < len(items); i++ {
if !items[i].expire.IsZero() && now.After(items[i].expire) {
items[i].mac = nil
items[i].expire = time.Time{}
}
}
p.mutex.Unlock()
}
}()
return p, nil
}
// AssignIP assigns an ip to mac from dhco pool.
func (p *Pool) AssignIP(mac net.HardwareAddr) (net.IP, error) {
var ip net.IP
// LeaseIP leases an ip to mac from dhcp pool.
func (p *Pool) LeaseIP(mac net.HardwareAddr) (net.IP, error) {
p.mutex.Lock()
defer p.mutex.Unlock()
for _, item := range p.items {
if bytes.Equal(mac, item.mac) {
return item.ip, nil
@ -43,39 +69,35 @@ func (p *Pool) AssignIP(mac net.HardwareAddr) (net.IP, error) {
idx := rand.Intn(len(p.items))
for _, item := range p.items[idx:] {
if ip = item.take(mac); ip != nil {
return ip, nil
if item.mac == nil {
item.mac = mac
item.expire = time.Now().Add(p.lease)
return item.ip, nil
}
}
for _, item := range p.items {
if ip = item.take(mac); ip != nil {
return ip, nil
if item.mac == nil {
item.mac = mac
item.expire = time.Now().Add(p.lease)
return item.ip, nil
}
}
return nil, errors.New("no more ip can be assigned")
return nil, errors.New("no more ip can be leased")
}
type item struct {
taken bool
ip net.IP
lease time.Duration
mac net.HardwareAddr
}
// ReleaseIP releases ip from pool according to the given mac.
func (p *Pool) ReleaseIP(mac net.HardwareAddr) {
p.mutex.Lock()
defer p.mutex.Unlock()
func (i *item) take(addr net.HardwareAddr) net.IP {
if !i.taken {
i.taken = true
go func() {
timer := time.NewTimer(i.lease)
<-timer.C
i.mac = nil
i.taken = false
}()
i.mac = addr
return i.ip
for _, item := range p.items {
if bytes.Equal(mac, item.mac) {
item.mac = nil
item.expire = time.Time{}
}
}
return nil
}
func ip2num(ip net.IP) uint32 {