1#! /usr/bin/env python
2# RFC 7348 - Virtual eXtensible Local Area Network (VXLAN):
3# A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
4# http://tools.ietf.org/html/rfc7348
5# https://www.ietf.org/id/draft-ietf-nvo3-vxlan-gpe-02.txt
6#
7# VXLAN Group Policy Option:
8# http://tools.ietf.org/html/draft-smith-vxlan-group-policy-00
9
10from scapy.packet import Packet, bind_layers
11from scapy.layers.l2 import Ether
12from scapy.layers.inet import IP, UDP
13from scapy.layers.inet6 import IPv6
14from scapy.fields import FlagsField, XByteField, ThreeBytesField, \
15    ConditionalField, ShortField, ByteEnumField, X3BytesField
16
17_GP_FLAGS = ["R", "R", "R", "A", "R", "R", "D", "R"]
18
19
20class VXLAN(Packet):
21    name = "VXLAN"
22
23    fields_desc = [
24        FlagsField("flags", 0x8, 8,
25                   ['OAM', 'R', 'NextProtocol', 'Instance',
26                    'V1', 'V2', 'R', 'G']),
27        ConditionalField(
28            ShortField("reserved0", 0),
29            lambda pkt: pkt.flags.NextProtocol,
30        ),
31        ConditionalField(
32            ByteEnumField('NextProtocol', 0,
33                          {0: 'NotDefined',
34                           1: 'IPv4',
35                           2: 'IPv6',
36                           3: 'Ethernet',
37                           4: 'NSH'}),
38            lambda pkt: pkt.flags.NextProtocol,
39        ),
40        ConditionalField(
41            ThreeBytesField("reserved1", 0),
42            lambda pkt: (not pkt.flags.G) and (not pkt.flags.NextProtocol),
43        ),
44        ConditionalField(
45            FlagsField("gpflags", 0, 8, _GP_FLAGS),
46            lambda pkt: pkt.flags.G,
47        ),
48        ConditionalField(
49            ShortField("gpid", 0),
50            lambda pkt: pkt.flags.G,
51        ),
52        X3BytesField("vni", 0),
53        XByteField("reserved2", 0),
54    ]
55
56    # Use default linux implementation port
57    overload_fields = {
58        UDP: {'dport': 8472},
59    }
60
61    def mysummary(self):
62        if self.flags.G:
63            return self.sprintf("VXLAN (vni=%VXLAN.vni% gpid=%VXLAN.gpid%)")
64        else:
65            return self.sprintf("VXLAN (vni=%VXLAN.vni%)")
66
67bind_layers(UDP, VXLAN, dport=4789)  # RFC standard vxlan port
68bind_layers(UDP, VXLAN, dport=4790)  # RFC standard vxlan-gpe port
69bind_layers(UDP, VXLAN, dport=6633)  # New IANA assigned port for use with NSH
70bind_layers(UDP, VXLAN, dport=8472)  # Linux implementation port
71bind_layers(UDP, VXLAN, sport=4789)
72bind_layers(UDP, VXLAN, sport=4790)
73bind_layers(UDP, VXLAN, sport=6633)
74bind_layers(UDP, VXLAN, sport=8472)
75# By default, set both ports to the RFC standard
76bind_layers(UDP, VXLAN, sport=4789, dport=4789)
77
78bind_layers(VXLAN, Ether)
79bind_layers(VXLAN, IP, NextProtocol=1)
80bind_layers(VXLAN, IPv6, NextProtocol=2)
81bind_layers(VXLAN, Ether, flags=4, NextProtocol=0)
82bind_layers(VXLAN, IP, flags=4, NextProtocol=1)
83bind_layers(VXLAN, IPv6, flags=4, NextProtocol=2)
84bind_layers(VXLAN, Ether, flags=4, NextProtocol=3)
85