## This file is part of Scapy
## See http://www.secdev.org/projects/scapy for more informations
## Copyright (C) Philippe Biondi <phil@secdev.org>
## This program is published under a GPLv2 license

"""
Clone of queso OS fingerprinting
"""

from scapy.data import KnowledgeBase
from scapy.config import conf
from scapy.layers.inet import IP,TCP
from scapy.error import warning
from scapy.volatile import RandInt
from scapy.sendrecv import sr
#from 

conf.queso_base ="/etc/queso.conf"


#################
## Queso stuff ##
#################


def quesoTCPflags(flags):
    if flags == "-":
        return "-"
    flv = "FSRPAUXY"
    v = 0
    for i in flags:
        v |= 2**flv.index(i)
    return "%x" % v

class QuesoKnowledgeBase(KnowledgeBase):
    def lazy_init(self):
        try:
            f = open(self.filename)
        except IOError:
            return
        self.base = {}
        p = None
        try:
            for l in f:
                l = l.strip()
                if not l or l[0] == ';':
                    continue
                if l[0] == '*':
                    if p is not None:
                        p[""] = name
                    name = l[1:].strip()
                    p = self.base
                    continue
                if l[0] not in list("0123456"):
                    continue
                res = l[2:].split()
                res[-1] = quesoTCPflags(res[-1])
                res = " ".join(res)
                if res not in p:
                    p[res] = {}
                p = p[res]
            if p is not None:
                p[""] = name
        except:
            self.base = None
            warning("Can't load queso base [%s]", self.filename)
        f.close()
            
        
queso_kdb = QuesoKnowledgeBase(conf.queso_base)

    
def queso_sig(target, dport=80, timeout=3):
    p = queso_kdb.get_base()
    ret = []
    for flags in ["S", "SA", "F", "FA", "SF", "P", "SEC"]:
        ans, unans = sr(IP(dst=target)/TCP(dport=dport,flags=flags,seq=RandInt()),
                        timeout=timeout, verbose=0)
        if len(ans) == 0:
            rs = "- - - -"
        else:
            s,r = ans[0]
            rs = "%i" % (r.seq != 0)
            if not r.ack:
                r += " 0"
            elif r.ack-s.seq > 666:
                rs += " R" % 0
            else:
                rs += " +%i" % (r.ack-s.seq)
            rs += " %X" % r.window
            rs += " %x" % r.payload.flags
        ret.append(rs)
    return ret
            
def queso_search(sig):
    p = queso_kdb.get_base()
    sig.reverse()
    ret = []
    try:
        while sig:
            s = sig.pop()
            p = p[s]
            if "" in p:
                ret.append(p[""])
    except KeyError:
        pass
    return ret
        

@conf.commands.register
def queso(*args,**kargs):
    """Queso OS fingerprinting
queso(target, dport=80, timeout=3)"""
    return queso_search(queso_sig(*args, **kargs))


