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Fix DHCPv4 options encoding #22

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Merged
mosajjal merged 2 commits into from
Jul 27, 2023
Merged

Fix DHCPv4 options encoding #22

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7c36ea3
Add DHCPv4 no options test
aibor Jul 26, 2023
29bbec8
Fix DHCPv4 options encoding
aibor Apr 26, 2023
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18 changes: 18 additions & 0 deletions layers/dhcp_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,24 @@ func TestDHCPv4EncodeRequest(t *testing.T) {
testDHCPEqual(t, dhcp, dhcp2)
}

func TestDHCPv4EncodeRequestNoOptions(t *testing.T) {
dhcp := &DHCPv4{Operation: DHCPOpRequest, HardwareType: LinkTypeEthernet, Xid: 0x12345678,
ClientIP: net.IP{0, 0, 0, 0}, YourClientIP: net.IP{0, 0, 0, 0}, NextServerIP: net.IP{0, 0, 0, 0}, RelayAgentIP: net.IP{0, 0, 0, 0},
ClientHWAddr: net.HardwareAddr{0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc},
ServerName: make([]byte, 64), File: make([]byte, 128)}

buf := gopacket.NewSerializeBuffer()
opts := gopacket.SerializeOptions{FixLengths: true}
err := gopacket.SerializeLayers(buf, opts, dhcp)
if err != nil {
t.Fatal(err)
}

p2 := gopacket.NewPacket(buf.Bytes(), LayerTypeDHCPv4, testDecodeOptions)
dhcp2 := p2.Layer(LayerTypeDHCPv4).(*DHCPv4)
testDHCPEqual(t, dhcp, dhcp2)
}

func TestDHCPv4EncodeResponse(t *testing.T) {
dhcp := &DHCPv4{Operation: DHCPOpReply, HardwareType: LinkTypeEthernet, Xid: 0x12345678,
ClientIP: net.IP{0, 0, 0, 0}, YourClientIP: net.IP{192, 168, 0, 123}, NextServerIP: net.IP{192, 168, 0, 1}, RelayAgentIP: net.IP{0, 0, 0, 0},
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10 changes: 5 additions & 5 deletions layers/dhcpv4.go
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Original file line number Diff line number Diff line change
Expand Up @@ -222,8 +222,8 @@ func (d *DHCPv4) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.Serialize
copy(data[108:236], d.File)
binary.BigEndian.PutUint32(data[236:240], DHCPMagic)

offset := 240
if len(d.Options) > 0 {
offset := 240
for _, o := range d.Options {
if err := o.encode(data[offset:]); err != nil {
return err
Expand All @@ -235,10 +235,10 @@ func (d *DHCPv4) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.Serialize
offset += 2 + len(o.Data)
}
}
optend := NewDHCPOption(DHCPOptEnd, nil)
if err := optend.encode(data[offset:]); err != nil {
return err
}
}
optend := NewDHCPOption(DHCPOptEnd, nil)
if err := optend.encode(data[offset:]); err != nil {
return err
}
return nil
}
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