网络编程01

Socket address

1.AF_UNIX: string
2.AF_INET: tuple(host,port)
3.AF_INET6:tuple(host,port,flowinfo,scopeid)

Socket 传输类型

1.socket.SOCK_STREAM
2.socket.SOCK_DGRAM
3.socket.SOCK_RAW

协议类型

1.MSG_*
2.SOL_*
3.IPPROTO_*
4.IPPORT_*
5.INADDR_*
6.IP_*
7.IPV6_*
8.EAI_*
9.AI_*
10.NI_*
11.TCP_*

传输层相关常用的函数

1.socket.socket(socket_family,socket_type,prtocol)
2.socket.bind(address)
3.socket.listen(backlog)#backlog是等候队列的数量
4.socket.accept()#return (socket,address)
5.socket.connect(address)
6.socket.connect_ex(address)#出错时返回错误代码
7.socket.recv(bufsize[,flags])
    返回tcp数据，bufsize是最大返回值
    flags参照[Unix](http://www.sbras.ru/cgi-bin/www/unix_help/unix-man?recv+2)
8.socket.send(string[,flags])#发送tcp数据 return 发送的字节
9.socket.send(string[,flags])#持续的发送string中的数据直到完成或者出现错误，none无错误返回值
10.socket.recvfrom(bufsize[,flags])#从UDP返回数据
11.socket.sendto(string,address)
12.socket.sendto(string,flags,address)#发送UDP数据

其他常用的函数

1.socket.getpeername()#Return the remote address to which the socket is connected.
2.socket.getsockname()#Return the socket’s own address
3.socket.getsockopt(level,optname[,buflen])
    
4.socket.setsockopt(level,opname,value)#设置socket参数
    #文档说see the optional built-in module struct for a way to encode C structures as strings
5.socket.close()

TCP/IP 小例子IP包解析（Python 2.7+Linux）

类型定义

class IP_pk(object):
    def __init__(self,list):
        self.version=binary_move(list[0],1,4,8)
        self.hlen=binary_move(list[0],5,8,8)*4
        self.tos=list[1]
        self.tolen=list[2]
        self.identify=list[3]
        self.flags=binary_move(list[4],1,4,16)
        self.fragmentoffset=binary_move(list[4],5,16,16)
        self.ttl=list[5]
        self.protocol=list[6]
        self.checksum=list[7]
        self.sourip=list[8]
        self.destip=list[9]

    def show(self):
        re = str()
        re = re + "Version:" + str(self.version)+"\r\n"
        re = re + "HeaderLength:" + str(self.hlen)+"\r\n"
        re = re + "totallengh:" + str(self.tolen)+"\r\n"
        re = re + "identify:" + str(self.identify)+"\r\n"
        re = re + "flags:" + flags_translate(self.flags)+"\r\n"
        re = re + "Fragment Offset" + str(self.fragmentoffset)+"\r\n"
        re = re + "TTL:" + str(self.ttl)+"\r\n"
        re = re + "Protocol:" + protocol_traslate(self.protocol) + "(" + str(self.protocol) + ")"+"\r\n"
        re = re + "checksum:" + hex(self.checksum) + "(" + str(self.checksum) + ")"+"\r\n"
        re = re + "sourip:" + socket.inet_ntoa(struct.pack("!I", self.sourip))+"\r\n"
        re = re + "destip:" + socket.inet_ntoa(struct.pack("!I", self.destip))+"\r\n"
        return re

class TCP_header(object):
    def __init__(self,list):
        self.src=list[0]
        self.dst=list[1]
        self.sequence=list[2]
        self.ack=list[3]
        self.dataoffset=binary_move(list[4],1,4,16)*4
        self.reserved=binary_move(list[4],5,10,16)
        self.control=binary_move(list[4],11,16,16)
        self.windowsize=list[5]
        self.checksum=list[6]
        self.urgentpointer=list[7]
    def show(self):
        re = str()
        re = "Source Port:" + str(self.src) + "\r\n"
        re = re + "Destination Port:" + str(self.dst) + "\r\n"
        re = re + "Sequece Number:" + str(hex(self.sequence)) + "\r\n"
        re = re + "ACK Number:" + str(hex(self.ack)) + "\r\n"
        re = re + "Data Offest:" + str(self.dataoffset) + "\r\n"
        re = re + "Reserved:" + bin(self.reserved) + "\r\n"
        re = re + "Control:" + tcp_control(self.control) + "\r\n"
        re = re + "Windows size:" + hex(self.windowsize) + "\r\n"
        re = re + "Checksum:" + hex(self.checksum) + "\r\n"
        re = re + "Urgent Pointer:"+str(self.urgentpointer)+"\r\n"
        return re

class UDP_header(object):
    def __init__(self,list):
        self.soreport=list[0]
        self.destport=list[1]
        self.checksum=list[2]
        self.tolen=list[3]
    def show(self):
        re = str()
        re="Source Port:"+str(self.soreport)+"\r\n"
        re = re + "Dest Port:" + str(self.destport) + "\r\n"
        re = re + "Checksum:" + str(self.checksum) + "\r\n"
        re = re + "Tolength:" + str(self.tolen)+"\r\n"
        return re

解析函数

def tcp_anly(ip_pk,ordata):
    re=str()
    re= "=====================Translate Protocol=====================\r\n"
    #将传入的ordata按照tcp头部解析
    tcp_header = TCP_header(struct.unpack("!2H2I4H", ordata[ip_pk.hlen:ip_pk.hlen + 20]))
    re = re + tcp_header.show()
    #解析tcp选项部分
    if tcp_header.dataoffset > 20:
        tcp_options_length = tcp_header.dataoffset - 20
        start = ip_pk.hlen + 20
        one=struct.unpack("!1B",ordata[start:start+1])
        start=start+1
        while one[0]!=0 :
            if one[0]==1:
                pass;
            if one[0]==2:
                two=struct.unpack("!1B",ordata[start:start+1])
                start = start + 1
                if two==4:
                    re=re+"MSS:"+str(bin(struct.unpack("!1H",ordata[start:start+2])))+"\r\n"
                    start=start+2
            if one[0] == 3:
                two = struct.unpack("!1B", ordata[start:start + 1])
                start = start + 1
                if two[0] == 3:
                    re = re + "Window Move Number:" + str("".join(map(bin,struct.unpack("!1B", ordata[start:start + 1])))) + "\r\n"
                    start = start + 1
            if one[0] == 8:
                two = struct.unpack("!1B", ordata[start:start + 1])
                start = start + 1
                if two[0] == 10:
                    re = re + "Timestamp:" + str(str(struct.unpack("!1I", ordata[start:start + 4])[0])) + "\r\n"
                    start = start + 4
                    re = re + "Timestam reply:" + str(str(struct.unpack("!1I", ordata[start:start + 4])[0])) + "\r\n"
                    start = start +4
            #print start
            if start>=ip_pk.hlen+tcp_header.dataoffset:
                break;
            one=struct.unpack("!1B",ordata[start:start+1])
            start=start+1
    re = re + "=====================Data Part==========================="+"\r\n"
    #应用层协议部分
    datastart = tcp_header.dataoffset + ip_pk.hlen
    if datastart != 0:
        datapart = struct.unpack("!" + str(ip_pk.tolen - datastart) + "c", ordata[datastart:ip_pk.tolen])
        re = re + "".join(datapart)+"\r\n"
    return re

def udp_anly(ip_pk,ordata):
    re = str()
    re = "=====================Translate Protocol=====================\r\n"
    data=struct.unpack("!4H",ordata[ip_pk.hlen:ip_pk.hlen+8])
    udp_header=UDP_header(data)
    re = re + udp_header.show()
    re = re + "=====================Data Part===========================" + "\r\n"
    datastart = ip_pk.hlen+8
    #print datastart, ip_pk.tolen
    if datastart != 0:
        datapart = struct.unpack("!" + str(ip_pk.tolen - datastart) + "c", ordata[datastart:ip_pk.tolen])
        re = re + "".join(datapart)+"\r\n"
    return re

中间函数

def tcpget(logpath="tcplog.txt"):
    f=open(logpath,"w")
    #通过socket函数创建一个SOCK_RAW,TCP的socket对象
    s=socket.socket(socket.AF_INET,socket.SOCK_RAW,socket.IPPROTO_TCP)
    #报文解析
    while True:
        ordata=s.recv(65535);
        #通过struct包中函数对接收到的数据进行网络-->本机字节的转换
        data=struct.unpack("!2B3H2B1H2I",ordata[0:20])
        #解析ip首部
        ip_pk=IP_pk(data[0:20])
        f.write("=====================NetWork Protocol=====================\r\n")
        f.write(ip_pk.show())
        #解析ip选项字段
        ip_options_length=ip_pk.hlen-20
        if ip_options_length!=0:
            choosepart=struct.unpack("!"+str(ip_options_length)+"c",ordata[20:ip_pk.hlen])
            f.write("choosepart:" + "".join(choosepart))
        #调用tcp_anly函数对余下的数据进行tcp解析
        f.write(tcp_anly(ip_pk,ordata))
        f.flush()
    f.close()

def udpget(logpath="udplog.txt"):
    f = open(logpath, "w")
    #通过socket函数创建一个SOCK_RAW,UDP的socket对象
    #说明同上
    s=socket.socket(socket.AF_INET,socket.SOCK_RAW,socket.IPPROTO_UDP)
    while True:
        ordata,address=s.recvfrom(65535);
        print len(ordata)
        data=struct.unpack("!2B3H2B1H2I",ordata[0:20])
        ip_pk=IP_pk(data[0:20])
        f.write("=====================NetWork Protocol=====================\r\n")
        f.write(ip_pk.show())
        ip_options_length=ip_pk.hlen-20
        if ip_options_length!=0:
            choosepart=struct.unpack("!"+str(ip_options_length)+"c",ordata[20:ip_pk.hlen])
            f.write("  choosepart:"+"".join(choosepart))

        f.write(udp_anly(ip_pk,ordata))
        f.flush()
    f.close()

遇到的问题：

1.Errno 10013：端口占用
2.listen(que_count)不要忘了参数