[INET6] add the PREF64 ND option (#4105)

Author: evverx

scapy/layers/inet6.py

@@ -1720,6 +1720,7 @@ def extract_padding(self, s):
                   26: "ICMPv6NDOptEFA",
                   31: "ICMPv6NDOptDNSSL",
                   37: "ICMPv6NDOptCaptivePortal",
+                  38: "ICMPv6NDOptPREF64",
                   }
 
 icmp6ndraprefs = {0: "Medium (default)",
@@ -2087,6 +2088,28 @@ class ICMPv6NDOptCaptivePortal(_ICMPv6NDGuessPayload, Packet):  # RFC 8910
     def mysummary(self):
         return self.sprintf("%name% %URI%")
 
+
+class _PREF64(IP6Field):
+    def addfield(self, pkt, s, val):
+        return s + self.i2m(pkt, val)[:12]
+
+    def getfield(self, pkt, s):
+        return s[12:], self.m2i(pkt, s[:12] + b"\x00" * 4)
+
+
+class ICMPv6NDOptPREF64(_ICMPv6NDGuessPayload, Packet):  # RFC 8781
+    name = "ICMPv6 Neighbor Discovery Option - PREF64 Option"
+    fields_desc = [ByteField("type", 38),
+                   ByteField("len", 2),
+                   BitField("scaledlifetime", 0, 13),
+                   BitEnumField("plc", 0, 3,
+                                ["/96", "/64", "/56", "/48", "/40", "/32"]),
+                   _PREF64("prefix", "::")]
+
+    def mysummary(self):
+        plc = self.sprintf("%plc%") if self.plc < 6 else f"[invalid PLC({self.plc})]"
+        return self.sprintf("%name% %prefix%") + plc
+
 # End of ICMPv6 Neighbor Discovery Options.
 
 

test/scapy/layers/inet6.uts

@@ -1250,6 +1250,32 @@ a=ICMPv6NDOptEFA(b'\x1a\x01\x00\x00\x00\x00\x00\x00')
 a.type==26 and a.len==1 and a.res == 0
 
 
+############
+############
++ ICMPv6NDOptPREF64 Class Test
+
+= ICMPv6NDOptPREF64 - Basic Instantiation
+raw(ICMPv6NDOptPREF64()) == b'\x26\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
+
+= ICMPv6NDOptPREF64 - Basic Dissection
+p = ICMPv6NDOptPREF64(b'\x26\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+assert p.type == 38 and p.len == 2 and p.scaledlifetime == 0 and p.plc == 0 and p.prefix == '::'
+
+= ICMPv6NDOptPREF64 - Instantiation/Dissection with specific values
+p = ICMPv6NDOptPREF64(scaledlifetime=225, plc='/64', prefix='2003:da8:1::')
+assert raw(p) == b'\x26\x02\x07\x09\x20\x03\x0d\xa8\x00\x01\x00\x00\x00\x00\x00\x00'
+
+p = ICMPv6NDOptPREF64(raw(p))
+assert p.type == 38 and p.len == 2 and p.scaledlifetime == 225 and p.plc == 1 and p.prefix == '2003:da8:1::'
+
+p = ICMPv6NDOptPREF64(raw(p) + b'\x00\x00\x00\x00')
+assert Raw in p and len(p[Raw]) == 4
+
+= ICMPv6NDOptPREF64 - Summary Output
+ICMPv6NDOptPREF64(prefix='12:34:56::', plc='/32').mysummary() == "ICMPv6 Neighbor Discovery Option - PREF64 Option 12:34:56::/32"
+ICMPv6NDOptPREF64(prefix='12:34:56::', plc=6).mysummary() == "ICMPv6 Neighbor Discovery Option - PREF64 Option 12:34:56::[invalid PLC(6)]"
+
+
 ############
 ############
 + Test Node Information Query - ICMPv6NIQueryNOOP