import external_packages
import random
import string
import struct
import socket       
import json
import yaml
import binascii
import base64


from scapy.all import *



class CTRexPacketBuildException(Exception):
    """
    This is the general Packet Building error exception class.
    """
    def __init__(self, code, message):
        self.code = code
        self.message = message

    def __str__(self):
        return self.__repr__()

    def __repr__(self):
        return u"[errcode:%r] %r" % (self.code, self.message)

################################################################################################

def ipv4_str_to_num (ipv4_buffer):

    assert(type(ipv4_buffer)==str);
    assert(len(ipv4_buffer)==4);
    res=0;
    shift=24
    for i in ipv4_buffer:
       res = res + (ord(i)<<shift);
       shift =shift -8
    return res



def is_valid_ipv4(ip_addr):
    """
    return buffer in network order 
    """
    if  type(ip_addr)==str and len(ip_addr) == 4:
        return ip_addr

    if  type(ip_addr)==int :
        ip_addr = socket.inet_ntoa(struct.pack("!I", ip_addr)) 

    try:
        return socket.inet_pton(socket.AF_INET, ip_addr)
    except AttributeError:  # no inet_pton here, sorry
        return socket.inet_aton(ip_addr)
    except socket.error:  # not a valid address
        raise CTRexPacketBuildException(-10,"not valid ipv4 format");


class CTRexScriptsBase(object):
    """
    VM Script base class 
    """
    def clone (self):
        return copy.deepcopy(self)


class CTRexScFieldRangeBase(CTRexScriptsBase):

    FILED_TYPES = ["inc","dec","rand"]  

    def __init__(self, field_name,
                       field_type
                            ):
        super(CTRexScFieldRangeBase, self).__init__()
        self.field_name =field_name
        self.field_type =field_type
        if not self.field_type in CTRexScFieldRangeBase.FILED_TYPES :
            raise CTRexPacketBuildException(-12,"field type should be in [inc,dec,rand] ");


class CTRexScFieldRangeValue(CTRexScFieldRangeBase):
    """
    range of field value
    """
    def __init__(self, field_name, 
                       field_type,
                       min_val,
                       max_val
                           ):
        super(CTRexScFieldRangeValue, self).__init__(field_name,field_type)
        self.min_val =min_val;
        self.max_val =max_val;
        if min_val > max_val:
            raise CTRexPacketBuildException(-12,"min is greater than max ");
        if min_val == max_val:
            raise CTRexPacketBuildException(-13,"min value is equal to max value, you can't use this type of range ");


class CTRexScIpv4SimpleRange(CTRexScFieldRangeBase):
    """
    range of ipv4 ip
    """
    def __init__(self, field_name,field_type,min_ip, max_ip):
        super(CTRexScIpv4SimpleRange, self).__init__(field_name,field_type)
        self.min_ip = min_ip
        self.max_ip = max_ip
        mmin=ipv4_str_to_num (is_valid_ipv4(min_ip))
        mmax=ipv4_str_to_num (is_valid_ipv4(max_ip))
        if  mmin > mmax :
            raise CTRexPacketBuildException(-11,"CTRexScIpv4SimpleRange m_min ip is bigger than max ");


class CTRexScIpv4TupleGen(CTRexScriptsBase):
    """
    range tuple 
    """
    FLAGS_ULIMIT_FLOWS =1

    def __init__(self, min_ipv4, max_ipv4,num_flows=100000,min_port=1025,max_port=65535,flags=0):
        super(CTRexScIpv4TupleGen, self).__init__()
        self.min_ip = min_ipv4
        self.max_ip = max_ipv4
        mmin=ipv4_str_to_num (is_valid_ipv4(min_ipv4))
        mmax=ipv4_str_to_num (is_valid_ipv4(max_ipv4))
        if  mmin > mmax :
            raise CTRexPacketBuildException(-11,"CTRexScIpv4SimpleRange m_min ip is bigger than max ");

        self.num_flows=num_flows;

        self.min_port =min_port
        self.max_port =max_port
        self.flags =   flags


class CTRexScTrimPacketSize(CTRexScriptsBase):
    """
    trim packet size. field type is CTRexScFieldRangeBase.FILED_TYPES = ["inc","dec","rand"]  
    """
    def __init__(self,field_type="rand",min_pkt_size=None, max_pkt_size=None):
        super(CTRexScTrimPacketSize, self).__init__()
        self.field_type = field_type
        self.min_pkt_size = min_pkt_size
        self.max_pkt_size = max_pkt_size
        if max_pkt_size != None and min_pkt_size !=None :
            if min_pkt_size == max_pkt_size:
                raise CTRexPacketBuildException(-11,"CTRexScTrimPacketSize min_pkt_size is the same as max_pkt_size ");

            if min_pkt_size > max_pkt_size:
                raise CTRexPacketBuildException(-11,"CTRexScTrimPacketSize min_pkt_size is bigger than max_pkt_size ");

class CTRexScRaw(CTRexScriptsBase):
    """
    raw instructions 
    """
    def __init__(self,list_of_commands=None):
        super(CTRexScRaw, self).__init__()
        if list_of_commands==None:
            self.commands =[]
        else:
            self.commands = list_of_commands

    def add_cmd (self,cmd):
        self.commands.append(cmd)



################################################################################################
# VM raw instructions 
################################################################################################

class CTRexVmInsBase(object):
    """
    instruction base
    """
    def __init__(self,ins_type):
        self.type = ins_type
        assert(type(ins_type)==str);

class CTRexVmInsFixIpv4(CTRexVmInsBase):
    def __init__(self,offset):
        super(CTRexVmInsFixIpv4, self).__init__("fix_checksum_ipv4")
        self.offset = offset
        assert(type(offset)==int);


class CTRexVmInsFlowVar(CTRexVmInsBase):
    #TBD add more validation tests

    OPERATIONS =["inc", "dec", "random"]
    VALID_SIZES =[1,2,4,8]

    def __init__(self,fv_name,size,op,init_val,min_val,max_val):
        super(CTRexVmInsFlowVar, self).__init__("flow_var")
        self.name =fv_name;
        assert(type(fv_name)==str);
        self.size =size
        self.op =op
        self.init_val=init_val
        assert(type(init_val)==int);
        self.min_val=min_val
        assert(type(min_val)==int);
        self.max_val=max_val
        assert(type(max_val)==int);

class CTRexVmInsWrFlowVar(CTRexVmInsBase):
    def __init__(self,fv_name,pkt_offset,add_val=0,is_big=True):
        super(CTRexVmInsWrFlowVar, self).__init__("write_flow_var")
        self.name =fv_name
        assert(type(fv_name)==str);
        self.pkt_offset =pkt_offset
        assert(type(pkt_offset)==int);
        self.add_val =add_val
        assert(type(add_val)==int);
        self.is_big =is_big;
        assert(type(is_big)==bool);

class CTRexVmInsTrimPktSize(CTRexVmInsBase):
    def __init__(self,fv_name):
        super(CTRexVmInsTrimPktSize, self).__init__("trim_pkt_size")
        self.fv_name =fv_name
        assert(type(fv_name)==str);

class CTRexVmInsTupleGen(CTRexVmInsBase):
    def __init__(self,fv_name,ip_min,ip_max,port_min,port_max,limit_flows,flags=0):
        super(CTRexVmInsTupleGen, self).__init__("tuple_flow_var")
        self.name =fv_name
        assert(type(fv_name)==str);
        self.ip_min = ip_min;
        self.ip_max = ip_max;
        self.port_min = port_min;
        self.port_max = port_max;
        self.limit_flows = limit_flows;
        self.flags       =flags;


################################################################################################
# 
class CTRexVmEngine(object):

       def __init__(self):
            """
            inlcude list of instruction
            """
            super(CTRexVmEngine, self).__init__()
            self.ins=[]
            self.split_by_var = ''

       # return as json 
       def get_json (self):
           inst_array = [];
           # dump it as dict
           for obj in self.ins:
               inst_array.append(obj.__dict__);

           return {'instructions': inst_array, 'split_by_var': self.split_by_var}

       def add_ins (self,ins):
           #assert issubclass(ins, CTRexVmInsBase)
           self.ins.append(ins);

       def dump (self):
           cnt=0;
           for obj in self.ins:
               print "ins",cnt
               cnt = cnt +1
               print obj.__dict__

       def dump_bjson (self):
          print json.dumps(self.get_json(), sort_keys=True, indent=4)

       def dump_as_yaml (self):
          print yaml.dump(self.get_json(), default_flow_style=False)



################################################################################################

class CTRexScapyPktUtl(object):

    def __init__(self,scapy_pkt):
        self.pkt = scapy_pkt

    def pkt_iter (self):
        p=self.pkt;
        while True:
            yield p
            p=p.payload
            if p ==None or isinstance(p,NoPayload):
                break;

    def get_list_iter (self):
        l=list(self.pkt_iter())
        return l


    def get_pkt_layers (self):
        """
        return string 'IP:UDP:TCP'
        """
        l=self.get_list_iter ();
        l1=map(lambda p: p.name,l );
        return ":".join(l1);

    def _layer_offset(self,name,cnt=0):
        """
        return offset of layer e.g 'IP',1 will return offfset of layer ip:1 
        """
        save_cnt=cnt
        for pkt in self.pkt_iter ():
            if pkt.name == name:
                if cnt==0:
                    return (pkt, pkt.offset)
                else:
                    cnt=cnt -1

        raise CTRexPacketBuildException(-11,("no layer %s-%d" % (name,save_cnt)));


    def layer_offset(self,name,cnt=0):
        """
        return offset of layer e.g 'IP',1 will return offfset of layer ip:1 
        """
        save_cnt=cnt
        for pkt in self.pkt_iter ():
            if pkt.name == name:
                if cnt==0:
                    return pkt.offset
                else:
                    cnt=cnt -1

        raise CTRexPacketBuildException(-11,("no layer %s-%d" % (name,save_cnt)));

    def get_field_offet(self,layer,layer_cnt,field_name):
        """
        return offset of layer e.g 'IP',1 will return offfset of layer ip:1 
        """
        t=self._layer_offset(layer,layer_cnt);
        l_offset=t[1];
        layer_pkt=t[0]

        #layer_pkt.dump_fields_offsets ()

        for f in layer_pkt.fields_desc:
            if f.name == field_name:
                return (l_offset+f.offset,f.get_size_bytes ());

        raise CTRexPacketBuildException(-11,("no layer %s-%d." % (name,save_cnt,field_name)));

    def  get_layer_offet_by_str(self,layer_des):
        """
        return layer offset by string  

       :parameters:

        IP:0
        IP:1
        return offset


        """
        l1=layer_des.split(":")
        layer=""
        layer_cnt=0;

        if len(l1)==1:
            layer=l1[0];
        else:
            layer=l1[0];
            layer_cnt=int(l1[1]);

        return self.layer_offset(layer,layer_cnt)



    def  get_field_offet_by_str(self,field_des):
        """
        return field_des (offset,size) layer:cnt.field 
        for example 
        802|1Q.vlan get 802.1Q->valn replace | with .
        IP.src
        IP:0.src  (first IP.src like IP.src)
        for example IP:1.src  for internal IP

        return (offset, size) as tuple 


        """

        s=field_des.split(".");
        if len(s)!=2:
            raise CTRexPacketBuildException(-11,("field desription should be layer:cnt.field e.g IP.src or IP:1.src "));


        layer_ex = s[0].replace("|",".")
        field = s[1]

        l1=layer_ex.split(":")
        layer=""
        layer_cnt=0;

        if len(l1)==1:
            layer=l1[0];
        else:
            layer=l1[0];
            layer_cnt=int(l1[1]);

        return self.get_field_offet(layer,layer_cnt,field)

    def has_IPv4 (self):
        return self.pkt.has_layer("IP");

    def has_IPv6 (self):
        return self.pkt.has_layer("IPv6");

    def has_UDP (self):
        return self.pkt.has_layer("UDP");

################################################################################################

class CTRexVmDescBase(object):
    """
    instruction base
    """
    def __init__(self):
       pass;

    def get_obj (self):
        return self;

    def get_json (self):
        return self.get_obj().__dict__

    def dump_bjson (self):
       print json.dumps(self.get_json(), sort_keys=True, indent=4)

    def dump_as_yaml (self):
       print yaml.dump(self.get_json(), default_flow_style=False)


    def get_var_name(self):
        '''
          virtual function return the varible name if exists
        ''' 
        return None

    def compile(self,parent): 
        '''
          virtual function to take parent than has function name_to_offset
        ''' 
        pass;


def valid_fv_size (size):
    if not (size in CTRexVmInsFlowVar.VALID_SIZES):
        raise CTRexPacketBuildException(-11,("flow var has not valid size %d ") % size  );

def valid_fv_ops (op):
    if not (op in CTRexVmInsFlowVar.OPERATIONS):
        raise CTRexPacketBuildException(-11,("flow var does not have a valid op %s ") % op  );

def convert_val (val):
    if type(val) == int:
        return val
    else:
        if type(val) == str:
          return ipv4_str_to_num (is_valid_ipv4(val))
        else:
            raise CTRexPacketBuildException(-11,("init val not valid %s ") % val  );


class CTRexVmDescFlowVar(CTRexVmDescBase):
    def __init__(self,name,init_val=0,min_val=0,max_val=255,size=4,op="inc"):
        super(CTRexVmDescFlowVar, self).__init__()
        self.name = name;
        assert(type(name)==str);
        self.size =size
        valid_fv_size(size)
        self.op =op
        valid_fv_ops (op)
        self.init_val = convert_val (init_val)
        self.min_val  = convert_val (min_val);
        self.max_val  = convert_val (max_val)

        if self.min_val > self.max_val :
            raise CTRexPacketBuildException(-11,("max %d is lower than min %d ") % (self.max_val,self.min_val)  );

    def get_obj (self):
        return CTRexVmInsFlowVar(self.name,self.size,self.op,self.init_val,self.min_val,self.max_val);

    def get_var_name(self):
        return self.name


class CTRexVmDescFixIpv4(CTRexVmDescBase):
    def __init__(self,offset):
        super(CTRexVmDescFixIpv4, self).__init__()
        self.offset = offset; # could be a name of offset 

    def get_obj (self):
        return CTRexVmInsFixIpv4(self.offset);

    def compile(self,parent): 
        if type(self.offset)==str:
            self.offset = parent._pkt_layer_offset(self.offset);

class CTRexVmDescWrFlowVar(CTRexVmDescBase):
    def __init__(self,fv_name,pkt_offset,offset_fixup=0,add_val=0,is_big=True):
        super(CTRexVmDescWrFlowVar, self).__init__()
        self.name =fv_name
        assert(type(fv_name)==str);
        self.offset_fixup =offset_fixup
        assert(type(offset_fixup)==int);
        self.pkt_offset =pkt_offset
        self.add_val =add_val
        assert(type(add_val)==int);
        self.is_big =is_big;
        assert(type(is_big)==bool);

    def get_obj (self):
            return  CTRexVmInsWrFlowVar(self.name,self.pkt_offset+self.offset_fixup,self.add_val,self.is_big)

    def compile(self,parent): 
        if type(self.pkt_offset)==str:
            t=parent._name_to_offset(self.pkt_offset)
            self.pkt_offset = t[0]


################################################################################################


class CScapyTRexPktBuilder(object):

    """
    This class defines the TRex API of building a packet using dpkt package.
    Using this class the user can also define how TRex will handle the packet by specifying the VM setting.
    """
    def __init__(self):
        """
        Instantiate a CTRexPktBuilder object

        :parameters:
             None

        """
        super(CScapyTRexPktBuilder, self).__init__()
        self._pkt = None # scapy packet 
        self.vm_scripts = [] # list of high level instructions
        self.vm_low_level = None
        self.metadata=""

    def get_vm_data(self):
        """
        Dumps the instructions 

        :parameters:
            None

        :return:
            + json object of instructions

        """

        return self.vm_low_level.get_json () 

    def dump_pkt(self):
        """
        Dumps the packet as a decimal array of bytes (each item x gets value between 0-255)

        :parameters:
            None

        :return:
            + packet representation as array of bytes

        :raises:
            + :exc:`CTRexPktBuilder.EmptyPacketError`, in case packet is empty.

        """

        assert(self.pkt);

        return {"binary": base64.b64encode(str(self.pkt)),
                "meta": self.metadata}


    def add_command (self,script):
        self.vm_scripts.append(script.clone());

    def dump_scripts (self):
        self.vm_low_level.dump_as_yaml ()

    def set_packet (self,pkt):
        """
        Scapy packet   Ether()/IP(src="16.0.0.1",dst="48.0.0.1")/UDP(dport=12,sport=1025)/IP()/"A"*10
        """
        self.pkt =pkt;


    def compile (self):
        self.vm_low_level=CTRexVmEngine()
        assert(self.pkt);
        self.pkt.build();

        
        for sc in self.vm_scripts:
            if isinstance(sc, CTRexScRaw):
                self._compile_raw (sc)

        #for obj in self.vm_scripts:
        #    # tuple gen script 
        #    if isinstance(obj, CTRexScIpv4TupleGen)
        #        self._add_tuple_gen(tuple_gen)

    ####################################################
    # private 

    def _compile_raw (self,obj):

        # make sure we have varibles once 
        vars={};
        for desc in obj.commands:
            print desc.__dict__
            var_name =  desc.get_var_name()
            print var_name
            if var_name :
                if vars.has_key(var_name):
                    raise CTRexPacketBuildException(-11,("varible %s define twice ") % (var_name)  );
                else:
                    vars[var_name]=1
            desc.compile(self);

        for desc in obj.commands:
            self.vm_low_level.add_ins(desc.get_obj());


    def _pkt_layer_offset (self,layer_name):
        assert(self.pkt != None);
        p_utl=CTRexScapyPktUtl(self.pkt);
        return p_utl.get_layer_offet_by_str(layer_name)

    def _name_to_offset(self,field_name):
        assert(self.pkt != None);
        p_utl=CTRexScapyPktUtl(self.pkt);
        return p_utl.get_field_offet_by_str(field_name)

    def  _add_tuple_gen(self,tuple_gen):

        pass;