vpp - Vector Packet Processing

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author	Dave Barach <dave@barachs.net>	2020-06-22 10:02:25 -0400
committer	Florin Coras <florin.coras@gmail.com>	2020-06-23 15:35:14 +0000
commit	b30b9549acaa0ffd4c94c2c50d0756416f9b58ee (patch)
tree	6aa6a41861d1a8383002da298235a992064fd85d /docs/gettingstarted/developers
parent	cc7209469601a29d0284c50716d876f685868c4b (diff)

vlib: debug CLI macro expander, part deux

Deal with circular macro definitions instead of crashing due to stack overflow. Separate macro tables, per CLI session Add documentation to the Sphinx docs Type: improvement Signed-off-by: Dave Barach <dave@barachs.net> Change-Id: I55fc9152bd37ad0c15fa3959f38b07b63100e634

Diffstat (limited to 'docs/gettingstarted/developers')

-rw-r--r--

docs/gettingstarted/developers/vlib.md

1 files changed, 48 insertions, 0 deletions

#! /usr/bin/env python # http://trac.secdev.org/scapy/ticket/162 # scapy.contrib.description = BGP # scapy.contrib.status = loads from scapy.packet import * from scapy.fields import * from scapy.layers.inet import TCP class BGPIPField(Field): """Represents how bgp dose an ip prefix in (length, prefix)""" def mask2iplen(self,mask): """turn the mask into the length in bytes of the ip field""" return (mask + 7) // 8 def h2i(self, pkt, h): """human x.x.x.x/y to internal""" ip,mask = re.split( '/', h) return int(mask), ip def i2h( self, pkt, i): mask, ip = i return ip + '/' + str( mask ) def i2repr( self, pkt, i): """make it look nice""" return self.i2h(pkt,i) def i2len(self, pkt, i): """rely on integer division""" mask, ip = i return self.mask2iplen(mask) + 1 def i2m(self, pkt, i): """internal (ip as bytes, mask as int) to machine""" mask, ip = i ip = inet_aton( ip ) return struct.pack(">B",mask) + ip[:self.mask2iplen(mask)] def addfield(self, pkt, s, val): return s+self.i2m(pkt, val) def getfield(self, pkt, s): l = self.mask2iplen( struct.unpack(">B",s[0])[0] ) + 1 return s[l:], self.m2i(pkt,s[:l]) def m2i(self,pkt,m): mask = struct.unpack(">B",m[0])[0] ip = "".join( [ m[i + 1] if i < self.mask2iplen(mask) else '\x00' for i in range(4)] ) return (mask,inet_ntoa(ip)) class BGPHeader(Packet): """The first part of any BGP packet""" name = "BGP header" fields_desc = [ XBitField("marker",0xffffffffffffffffffffffffffffffff, 0x80 ), ShortField("len", None), ByteEnumField("type", 4, {0:"none", 1:"open",2:"update",3:"notification",4:"keep_alive"}), ] def post_build(self, p, pay): if self.len is None and pay: l = len(p) + len(pay) p = p[:16]+struct.pack("!H", l)+p[18:] return p+pay class BGPOptionalParameter(Packet): """Format of optional Parameter for BGP Open""" name = "BGP Optional Parameters" fields_desc = [ ByteField("type", 2), ByteField("len", None), StrLenField("value", "", length_from = lambda x: x.len), ] def post_build(self,p,pay): if self.len is None: l = len(p) - 2 # 2 is length without value p = p[:1]+struct.pack("!B", l)+p[2:] return p+pay def extract_padding(self, p): """any thing after this packet is extracted is padding""" return "",p class BGPOpen(Packet): """ Opens a new BGP session""" name = "BGP Open Header" fields_desc = [ ByteField("version", 4), ShortField("AS", 0), ShortField("hold_time", 0), IPField("bgp_id","0.0.0.0"), ByteField("opt_parm_len", None), PacketListField("opt_parm",[], BGPOptionalParameter, length_from=lambda p:p.opt_parm_len), ] def post_build(self, p, pay): if self.opt_parm_len is None: l = len(p) - 10 # 10 is regular length with no additional options p = p[:9] + struct.pack("!B",l) +p[10:] return p+pay class BGPAuthenticationData(Packet): name = "BGP Authentication Data" fields_desc = [ ByteField("AuthenticationCode", 0), ByteField("FormMeaning", 0), FieldLenField("Algorithm", 0), ] class BGPPathAttribute(Packet): "the attribute of total path" name = "BGP Attribute fields" fields_desc = [ FlagsField("flags", 0x40, 8, ["NA0","NA1","NA2","NA3","Extended-Length","Partial","Transitive","Optional"]), #Extened leght may not work ByteEnumField("type", 1, {1:"ORIGIN", 2:"AS_PATH", 3:"NEXT_HOP", 4:"MULTI_EXIT_DISC", 5:"LOCAL_PREF", 6:"ATOMIC_AGGREGATE", 7:"AGGREGATOR"}), ByteField("attr_len", None), StrLenField("value", "", length_from = lambda p: p.attr_len), ] def post_build(self, p, pay): if self.attr_len is None: l = len(p) - 3 # 3 is regular length with no additional options p = p[:2] + struct.pack("!B",l) +p[3:] return p+pay def extract_padding(self, p): """any thing after this packet is extracted is padding""" return "",p class BGPUpdate(Packet): """Update the routes WithdrawnRoutes = UnfeasiableRoutes""" name = "BGP Update fields" fields_desc = [ ShortField("withdrawn_len", None), FieldListField("withdrawn",[], BGPIPField("","0.0.0.0/0"), length_from=lambda p:p.withdrawn_len), ShortField("tp_len", None), PacketListField("total_path", [], BGPPathAttribute, length_from = lambda p: p.tp_len), FieldListField("nlri",[], BGPIPField("","0.0.0.0/0"), length_from=lambda p:p.underlayer.len - 23 - p.tp_len - p.withdrawn_len), # len should be BGPHeader.len ] def post_build(self,p,pay): wl = self.withdrawn_len subpacklen = lambda p: len ( str( p )) subfieldlen = lambda p: BGPIPField("", "0.0.0.0/0").i2len(self, p ) if wl is None: wl = sum ( map ( subfieldlen , self.withdrawn)) p = p[:0]+struct.pack("!H", wl)+p[2:] if self.tp_len is None: l = sum ( map ( subpacklen , self.total_path)) p = p[:2+wl]+struct.pack("!H", l)+p[4+wl:] return p+pay class BGPNotification(Packet): name = "BGP Notification fields" fields_desc = [ ByteEnumField("ErrorCode",0,{1:"Message Header Error",2:"OPEN Message Error",3:"UPDATE Messsage Error",4:"Hold Timer Expired",5:"Finite State Machine",6:"Cease"}), ByteEnumField("ErrorSubCode",0,{1:"MessageHeader",2:"OPENMessage",3:"UPDATEMessage"}), LongField("Data", 0), ] class BGPErrorSubcodes(Packet): name = "BGP Error Subcodes" Fields_desc = [ ByteEnumField("MessageHeader",0,{1:"Connection Not Synchronized",2:"Bad Message Length",3:"Bad Messsage Type"}), ByteEnumField("OPENMessage",0,{1:"Unsupported Version Number",2:"Bad Peer AS",3:"Bad BGP Identifier",4:"Unsupported Optional Parameter",5:"Authentication Failure",6:"Unacceptable Hold Time"}), ByteEnumField("UPDATEMessage",0,{1:"Malformed Attribute List",2:"Unrecognized Well-Known Attribute",3:"Missing Well-Known Attribute",4:"Attribute Flags Error",5:"Attribute Length Error",6:"Invalid ORIGIN Attribute",7:"AS Routing Loop",8:"Invalid NEXT_HOP Attribute",9:"Optional Attribute Error",10:"Invalid Network Field",11:"Malformed AS_PATH"}), ] bind_layers( TCP, BGPHeader, dport=179) bind_layers( TCP, BGPHeader, sport=179) bind_layers( BGPHeader, BGPOpen, type=1) bind_layers( BGPHeader, BGPUpdate, type=2) bind_layers( BGPHeader, BGPHeader, type=4) if __name__ == "__main__": interact(mydict=globals(), mybanner="BGP addon .05")


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