diff --git a/scapy/layers/inet.py b/scapy/layers/inet.py
index 4450df188b68a10f12d7003e1dd4f44960485e0f..e38a0990db288f52d90f3cbfd7d4e601b71d8513 100644
--- a/scapy/layers/inet.py
+++ b/scapy/layers/inet.py
@@ -475,6 +475,33 @@ class IP(Packet, IPTools):
lst.append(q)
return lst
+def in4_chksum(proto, u, p):
+ """
+ As Specified in RFC 2460 - 8.1 Upper-Layer Checksums
+
+ Performs IPv4 Upper Layer checksum computation. Provided parameters are:
+ - 'proto' : value of upper layer protocol
+ - 'u' : IP upper layer instance
+ - 'p' : the payload of the upper layer provided as a string
+ """
+ if not isinstance(u, IP):
+ warning("No IP underlayer to compute checksum. Leaving null.")
+ return 0
+ if u.len is not None:
+ if u.ihl is None:
+ olen = sum(len(x) for x in u.options)
+ ihl = 5 + olen / 4 + (1 if olen % 4 else 0)
+ else:
+ ihl = u.ihl
+ ln = u.len - 4 * ihl
+ else:
+ ln = len(p)
+ psdhdr = struct.pack("!4s4sHH",
+ inet_aton(u.src),
+ inet_aton(u.dst),
+ proto,
+ ln)
+ return checksum(psdhdr+p)
class TCP(Packet):
name = "TCP"
@@ -497,21 +524,7 @@ class TCP(Packet):
p = p[:12]+chr((dataofs << 4) | ord(p[12])&0x0f)+p[13:]
if self.chksum is None:
if isinstance(self.underlayer, IP):
- if self.underlayer.len is not None:
- if self.underlayer.ihl is None:
- olen = sum(len(x) for x in self.underlayer.options)
- ihl = 5 + olen / 4 + (1 if olen % 4 else 0)
- else:
- ihl = self.underlayer.ihl
- ln = self.underlayer.len - 4 * ihl
- else:
- ln = len(p)
- psdhdr = struct.pack("!4s4sHH",
- inet_aton(self.underlayer.src),
- inet_aton(self.underlayer.dst),
- self.underlayer.proto,
- ln)
- ck=checksum(psdhdr+p)
+ ck = in4_chksum(socket.IPPROTO_TCP, self.underlayer, p)
p = p[:16]+struct.pack("!H", ck)+p[18:]
elif conf.ipv6_enabled and isinstance(self.underlayer, scapy.layers.inet6.IPv6) or isinstance(self.underlayer, scapy.layers.inet6._IPv6ExtHdr):
ck = scapy.layers.inet6.in6_chksum(socket.IPPROTO_TCP, self.underlayer, p)
@@ -576,21 +589,7 @@ class UDP(Packet):
p = p[:4]+struct.pack("!H",l)+p[6:]
if self.chksum is None:
if isinstance(self.underlayer, IP):
- if self.underlayer.len is not None:
- if self.underlayer.ihl is None:
- olen = sum(len(x) for x in self.underlayer.options)
- ihl = 5 + olen / 4 + (1 if olen % 4 else 0)
- else:
- ihl = self.underlayer.ihl
- ln = self.underlayer.len - 4 * ihl
- else:
- ln = len(p)
- psdhdr = struct.pack("!4s4sHH",
- inet_aton(self.underlayer.src),
- inet_aton(self.underlayer.dst),
- self.underlayer.proto,
- ln)
- ck = checksum(psdhdr+p)
+ ck = in4_chksum(socket.IPPROTO_UDP, self.underlayer, p)
# According to RFC768 if the result checksum is 0, it should be set to 0xFFFF
if ck == 0:
ck = 0xFFFF
diff --git a/scapy/layers/inet6.py b/scapy/layers/inet6.py
index 5c25420ed8b3f9816a5b8599dfdb14650a700c24..e7e73cc48aff8a724a0a9593cbe8d1ed304b8a8c 100644
--- a/scapy/layers/inet6.py
+++ b/scapy/layers/inet6.py
@@ -292,6 +292,7 @@ ipv6nh = { 0:"Hop-by-Hop Option Header",
58:"ICMPv6",
59:"No Next Header",
60:"Destination Option Header",
+ 112:"VRRP",
132:"SCTP",
135:"Mobility Header"}
@@ -643,8 +644,9 @@ class PseudoIPv6(Packet): # IPv6 Pseudo-header for checksum computation
def in6_chksum(nh, u, p):
"""
- Performs IPv6 Upper Layer checksum computation. Provided parameters are:
+ As Specified in RFC 2460 - 8.1 Upper-Layer Checksums
+ Performs IPv6 Upper Layer checksum computation. Provided parameters are:
- 'nh' : value of upper layer protocol
- 'u' : upper layer instance (TCP, UDP, ICMPv6*, ). Instance must be
provided with all under layers (IPv6 and all extension headers,
diff --git a/scapy/layers/vrrp.py b/scapy/layers/vrrp.py
index f874b352ab8c2ef6a2e03e4d303acd5a23af8e6c..bd50e45b23bb1b226862f04c0a76e49b7a4db5ff 100644
--- a/scapy/layers/vrrp.py
+++ b/scapy/layers/vrrp.py
@@ -10,15 +10,17 @@ VRRP (Virtual Router Redundancy Protocol).
from scapy.packet import *
from scapy.fields import *
-from scapy.layers.inet import IP
+from scapy.layers.inet import *
+from scapy.layers.inet6 import *
+from scapy.error import warning
IPPROTO_VRRP=112
# RFC 3768 - Virtual Router Redundancy Protocol (VRRP)
class VRRP(Packet):
fields_desc = [
- BitField("version" , 2, 4),
- BitField("type" , 1, 4),
+ BitField("version", 2, 4),
+ BitField("type", 1, 4),
ByteField("vrid", 1),
ByteField("priority", 100),
FieldLenField("ipcount", None, count_of="addrlist", fmt="B"),
@@ -36,4 +38,51 @@ class VRRP(Packet):
p = p[:6]+chr(ck>>8)+chr(ck&0xff)+p[8:]
return p
+ @classmethod
+ def dispatch_hook(cls, _pkt=None, *args, **kargs):
+ if _pkt and len(_pkt) >= 9:
+ ver_n_type = ord(_pkt[0])
+ if ver_n_type >= 48 and ver_n_type <= 57: # Version == 3
+ return VRRPv3
+ return VRRP
+
+
+# RFC 5798 - Virtual Router Redundancy Protocol (VRRP) Version 3
+class VRRPv3(Packet):
+ fields_desc = [
+ BitField("version", 3, 4),
+ BitField("type", 1, 4),
+ ByteField("vrid", 1),
+ ByteField("priority", 100),
+ FieldLenField("ipcount", None, count_of="addrlist", fmt="B"),
+ BitField("res", 0, 4),
+ BitField("adv", 100, 12),
+ XShortField("chksum", None),
+ # FIXME: addrlist should also allow IPv6 addresses :/
+ FieldListField("addrlist", [], IPField("", "0.0.0.0"),
+ count_from = lambda pkt: pkt.ipcount)]
+
+ def post_build(self, p, pay):
+ if self.chksum is None:
+ if isinstance(self.underlayer, IP):
+ ck = in4_chksum(112, self.underlayer, p)
+ elif isinstance(self.underlayer, IPv6):
+ ck = in6_chksum(112, self.underlayer, p)
+ else:
+ warning("No IP(v6) layer to compute checksum on VRRP. Leaving null")
+ ck = 0
+ p = p[:6]+chr(ck>>8)+chr(ck&0xff)+p[8:]
+ return p
+
+ @classmethod
+ def dispatch_hook(cls, _pkt=None, *args, **kargs):
+ if _pkt and len(_pkt) >= 16:
+ ver_n_type = ord(_pkt[0])
+ if ver_n_type < 48 or ver_n_type > 57: # Version != 3
+ return VRRP
+ return VRRPv3
+
+# IPv6 is supported only on VRRPv3
bind_layers( IP, VRRP, proto=IPPROTO_VRRP)
+bind_layers( IP, VRRPv3, proto=IPPROTO_VRRP)
+bind_layers( IPv6, VRRPv3, nh=IPPROTO_VRRP)