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# NOTE: This patch copied from https://github.com/secdev/scapy
# commit 3e6900776698cd5472c5405294414d5b672a3f18
#
diff --git a/scapy/layers/ppp.py b/scapy/layers/ppp.py
index b5cd42b4..e0f4c593 100644
--- a/scapy/layers/ppp.py
+++ b/scapy/layers/ppp.py
@@ -292,6 +292,14 @@ class _PPPProtoField(EnumField):
See RFC 1661 section 2
<https://tools.ietf.org/html/rfc1661#section-2>
+
+ The generated proto field is two bytes when not specified, or when specified
+ as an integer or a string:
+ PPP()
+ PPP(proto=0x21)
+ PPP(proto="Internet Protocol version 4")
+ To explicitly forge a one byte proto field, use the bytes representation:
+ PPP(proto=b'\x21')
"""
def getfield(self, pkt, s):
if ord(s[:1]) & 0x01:
@@ -304,12 +312,18 @@ class _PPPProtoField(EnumField):
return super(_PPPProtoField, self).getfield(pkt, s)
def addfield(self, pkt, s, val):
- if val < 0x100:
- self.fmt = "!B"
- self.sz = 1
+ if isinstance(val, bytes):
+ if len(val) == 1:
+ fmt, sz = "!B", 1
+ elif len(val) == 2:
+ fmt, sz = "!H", 2
+ else:
+ raise TypeError('Invalid length for PPP proto')
+ val = struct.Struct(fmt).unpack(val)[0]
else:
- self.fmt = "!H"
- self.sz = 2
+ fmt, sz = "!H", 2
+ self.fmt = fmt
+ self.sz = sz
self.struct = struct.Struct(self.fmt)
return super(_PPPProtoField, self).addfield(pkt, s, val)
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