Fix Geneve dissection (#3917)

* fix Geneve dissection

* Removed accidentally added local files and added unit test.

* Little enhancement of Geneve multiple options test

* Removed redundant line from gitignore

Author: inthefog

.gitignore

@@ -11,6 +11,7 @@ coverage.xml
 .ipynb_checkpoints
 .mypy_cache
 .vscode
+.DS_Store
 [.]venv/
 __pycache__/
 doc/scapy/_build

scapy/contrib/geneve.py

@@ -43,6 +43,9 @@ class GeneveOptions(Packet):
                    BitField("length", None, 5),
                    StrLenField('data', '', length_from=lambda x: x.length * 4)]
 
+    def extract_padding(self, s):
+        return "", s
+
     def post_build(self, p, pay):
         if self.length is None:
             tmp_len = len(self.data) // 4

test/contrib/geneve.uts

@@ -30,6 +30,16 @@ assert (s == b'\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x81\x00\x00\x01\
 p = Ether(s)
 assert GENEVE in p and Ether in p[GENEVE].payload and p[GENEVE].proto == 0x6558 and p[GeneveOptions].length == 1 and p[GeneveOptions].classid == 0x102 and p[GeneveOptions].type == 0x80
 
+= Build & dissect - GENEVE with multiple options
+
+s = raw(GENEVE(proto=0x0800,options=[GeneveOptions(classid=0x0102,type=0x1,data=b'\x00\x01\x00\x02'), GeneveOptions(classid=0x0102,type=0x2,data=b'\x00\x01\x00\x02')]))
+p = GENEVE(s)
+assert p.optionlen == 4
+assert len(p.options) == 2
+assert p.options[0].classid == 0x102 and p.options[0].type == 0x1
+assert p.options[1].classid == 0x102 and p.options[1].type == 0x2
+
+
 = Build & dissect - GENEVE encapsulates IPv4
 
 s = raw(IP()/UDP(sport=10000)/GENEVE()/IP())