diff --git a/scapy/layers/ipsec.py b/scapy/layers/ipsec.py
-index f8c601fa..f566d288 100644
+index ae057ee1..d7a21e8b 100644
--- a/scapy/layers/ipsec.py
+++ b/scapy/layers/ipsec.py
-@@ -359,11 +359,8 @@ class CryptAlgo(object):
+@@ -56,6 +56,7 @@ from scapy.fields import ByteEnumField, ByteField, IntField, PacketField, \
+ ShortField, StrField, XIntField, XStrField, XStrLenField
+ from scapy.packet import Packet, bind_layers, Raw
+ from scapy.layers.inet import IP, UDP
++from scapy.contrib.mpls import MPLS
+ import scapy.modules.six as six
+ from scapy.modules.six.moves import range
+ from scapy.layers.inet6 import IPv6, IPv6ExtHdrHopByHop, IPv6ExtHdrDestOpt, \
+@@ -138,6 +139,7 @@ bind_layers(IP, ESP, proto=socket.IPPROTO_ESP)
+ bind_layers(IPv6, ESP, nh=socket.IPPROTO_ESP)
+ bind_layers(UDP, ESP, dport=4500) # NAT-Traversal encapsulation
+ bind_layers(UDP, ESP, sport=4500) # NAT-Traversal encapsulation
++bind_layers(UDP, ESP, dport=4545) # NAT-Traversal encapsulation - random port
+
+ ###############################################################################
+
+@@ -359,11 +361,8 @@ class CryptAlgo(object):
encryptor = cipher.encryptor()
if self.is_aead:
data = encryptor.update(data) + encryptor.finalize()
data += encryptor.tag[:self.icv_size]
else:
-@@ -401,12 +398,7 @@ class CryptAlgo(object):
+@@ -400,12 +399,7 @@ class CryptAlgo(object):
if self.is_aead:
# Tag value check is done during the finalize method
try:
data = decryptor.update(data) + decryptor.finalize()
except InvalidTag as err:
-@@ -545,7 +537,7 @@ class AuthAlgo(object):
+@@ -445,6 +439,7 @@ if algorithms:
+ CRYPT_ALGOS['AES-CTR'] = CryptAlgo('AES-CTR',
+ cipher=algorithms.AES,
+ mode=modes.CTR,
++ block_size=1,
+ iv_size=8,
+ salt_size=4,
+ format_mode_iv=_aes_ctr_format_mode_iv)
+@@ -452,6 +447,7 @@ if algorithms:
+ CRYPT_ALGOS['AES-GCM'] = CryptAlgo('AES-GCM',
+ cipher=algorithms.AES,
+ mode=modes.GCM,
++ block_size=1,
+ salt_size=4,
+ iv_size=8,
+ icv_size=16,
+@@ -460,6 +456,7 @@ if algorithms:
+ CRYPT_ALGOS['AES-CCM'] = CryptAlgo('AES-CCM',
+ cipher=algorithms.AES,
+ mode=modes.CCM,
++ block_size=1,
+ iv_size=8,
+ salt_size=3,
+ icv_size=16,
+@@ -544,7 +541,7 @@ class AuthAlgo(object):
else:
return self.mac(key, self.digestmod(), default_backend())
"""
Sign an IPsec (ESP or AH) packet with this algo.
-@@ -561,16 +553,20 @@ class AuthAlgo(object):
+@@ -560,16 +557,20 @@ class AuthAlgo(object):
if pkt.haslayer(ESP):
mac.update(raw(pkt[ESP]))
"""
Check that the integrity check value (icv) of a packet is valid.
-@@ -602,6 +598,8 @@ class AuthAlgo(object):
+@@ -600,6 +601,8 @@ class AuthAlgo(object):
clone = zero_mutable_fields(pkt.copy(), sending=False)
mac.update(raw(clone))
computed_icv = mac.finalize()[:self.icv_size]
# XXX: Cannot use mac.verify because the ICV can be truncated
-@@ -864,6 +862,23 @@ class SecurityAssociation(object):
+@@ -788,7 +791,7 @@ class SecurityAssociation(object):
+ This class is responsible of "encryption" and "decryption" of IPsec packets. # noqa: E501
+ """
+
+- SUPPORTED_PROTOS = (IP, IPv6)
++ SUPPORTED_PROTOS = (IP, IPv6, MPLS)
+
+ def __init__(self, proto, spi, seq_num=1, crypt_algo=None, crypt_key=None,
+ auth_algo=None, auth_key=None, tunnel_header=None, nat_t_header=None, esn_en=False, esn=0): # noqa: E501
+@@ -862,6 +865,23 @@ class SecurityAssociation(object):
raise TypeError('nat_t_header must be %s' % UDP.name)
self.nat_t_header = nat_t_header
def check_spi(self, pkt):
if pkt.spi != self.spi:
raise TypeError('packet spi=0x%x does not match the SA spi=0x%x' %
-@@ -877,7 +892,8 @@ class SecurityAssociation(object):
+@@ -875,7 +895,8 @@ class SecurityAssociation(object):
if len(iv) != self.crypt_algo.iv_size:
raise TypeError('iv length must be %s' % self.crypt_algo.iv_size) # noqa: E501
if self.tunnel_header:
tunnel = self.tunnel_header.copy()
-@@ -901,7 +917,7 @@ class SecurityAssociation(object):
+@@ -899,7 +920,7 @@ class SecurityAssociation(object):
esn_en=esn_en or self.esn_en,
esn=esn or self.esn)
if self.nat_t_header:
nat_t_header = self.nat_t_header.copy()
-@@ -928,7 +944,8 @@ class SecurityAssociation(object):
+@@ -926,7 +947,8 @@ class SecurityAssociation(object):
def _encrypt_ah(self, pkt, seq_num=None):
icv=b"\x00" * self.auth_algo.icv_size)
if self.tunnel_header:
-@@ -968,7 +985,8 @@ class SecurityAssociation(object):
+@@ -966,7 +988,8 @@ class SecurityAssociation(object):
else:
ip_header.plen = len(ip_header.payload) + len(ah) + len(payload)
# sequence number must always change, unless specified by the user
if seq_num is None:
-@@ -1005,11 +1023,12 @@ class SecurityAssociation(object):
+@@ -1003,11 +1026,12 @@ class SecurityAssociation(object):
def _decrypt_esp(self, pkt, verify=True, esn_en=None, esn=None):
esp = self.crypt_algo.decrypt(self, encrypted, self.crypt_key,
self.crypt_algo.icv_size or
-@@ -1050,9 +1069,10 @@ class SecurityAssociation(object):
+@@ -1048,9 +1072,10 @@ class SecurityAssociation(object):
def _decrypt_ah(self, pkt, verify=True):
ah = pkt[AH]
payload = ah.payload
-