X-Git-Url: https://gerrit.fd.io/r/gitweb?p=csit.git;a=blobdiff_plain;f=resources%2Flibraries%2Fpython%2FPacketVerifier.py;h=78c367013564c77815b8538443b6ee21f7a06fa7;hp=566ea95c254187e7d83809658b6a8d71b8bd84bb;hb=c478afc5aec0161cc66e837c1ab919542b68ebbc;hpb=28bd0048f4ebc05c2706b13baf9ae63cedd58a64

diff --git a/resources/libraries/python/PacketVerifier.py b/resources/libraries/python/PacketVerifier.py
index 566ea95c25..78c3670135 100644
--- a/resources/libraries/python/PacketVerifier.py
+++ b/resources/libraries/python/PacketVerifier.py
@@ -63,20 +63,20 @@
 """
 
 
+import os
 import socket
 import select
-import os
-import time
-from multiprocessing import Queue, Process
+
 from scapy.all import ETH_P_IP, ETH_P_IPV6, ETH_P_ALL, ETH_P_ARP
 from scapy.all import Ether, ARP, Packet
 from scapy.layers.inet6 import IPv6
 
 __all__ = ['RxQueue', 'TxQueue', 'Interface', 'create_gratuitous_arp_request',
-           'auto_pad']
+           'auto_pad', 'checksum_equal']
 
 # TODO: http://stackoverflow.com/questions/320232/ensuring-subprocesses-are-dead-on-exiting-python-program
 
+
 class PacketVerifier(object):
     """Base class for TX and RX queue objects for packet verifier."""
     def __init__(self, interface_name):
@@ -95,10 +95,10 @@ def extract_one_packet(buf):
     Takes string as input and looks for first whole packet in it.
     If it finds one, it returns substring from the buf parameter.
 
-    :param buf: string representation of incoming packet buffer.
-    :type buf: string
+    :param buf: String representation of incoming packet buffer.
+    :type buf: str
     :return: String representation of first packet in buf.
-    :rtype: string
+    :rtype: str
     """
     pkt_len = 0
 
@@ -178,9 +178,9 @@ def packet_reader(interface_name, queue):
     This function is meant to be run in separate subprocess and is in tight
     loop reading raw packets from interface passed as parameter.
 
-    :param interace_name: Name of interface to read packets from.
+    :param interface_name: Name of interface to read packets from.
     :param queue: Queue in which this function will push incoming packets.
-    :type interface_name: string
+    :type interface_name: str
     :type queue: multiprocessing.Queue
     :return: None
     """
@@ -199,19 +199,11 @@ class RxQueue(PacketVerifier):
     function to access them.
 
     :param interface_name: Which interface to bind to.
-    :type interface_name: string
+    :type interface_name: str
     """
-
     def __init__(self, interface_name):
         PacketVerifier.__init__(self, interface_name)
 
-        #self._queue = Queue()
-        #self._proc = Process(target=packet_reader, args=(interface_name,
-        #                                                 self._queue))
-        #self._proc.daemon = True
-        #self._proc.start()
-        #time.sleep(2)
-
     def recv(self, timeout=3, ignore=None):
         """Read next received packet.
 
@@ -220,18 +212,19 @@ class RxQueue(PacketVerifier):
         arrives in given timeout queue.Empty exception will be risen.
 
         :param timeout: How many seconds to wait for next packet.
+        :param ignore: Packet list that should be ignored.
         :type timeout: int
+        :type ignore: list
 
         :return: Ether() initialized object from packet data.
         :rtype: scapy.Ether
         """
-
-        #pkt = self._queue.get(True, timeout=timeout)
         (rlist, _, _) = select.select([self._sock], [], [], timeout)
         if self._sock not in rlist:
             return None
 
         pkt = self._sock.recv(0x7fff)
+        pkt_pad = auto_pad(pkt)
         print 'Received packet on {0} of len {1}'.format(self._ifname, len(pkt))
         Ether(pkt).show2()
         print
@@ -241,7 +234,7 @@ class RxQueue(PacketVerifier):
                 # Auto pad all packets in ignore list
                 ignore[i] = auto_pad(ig_pkt)
             for ig_pkt in ignore:
-                if ig_pkt == pkt:
+                if ig_pkt == pkt_pad:
                     # Found the packet in ignore list, get another one
                     # TODO: subtract timeout - time_spent in here
                     ignore.remove(ig_pkt)
@@ -256,7 +249,7 @@ class TxQueue(PacketVerifier):
     This object is used to send packets over RAW socket on a interface.
 
     :param interface_name: Which interface to send packets from.
-    :type interface_name: string
+    :type interface_name: str
     """
     def __init__(self, interface_name):
         PacketVerifier.__init__(self, interface_name)
@@ -290,13 +283,9 @@ class Interface(object):
     def recv_pkt(self, timeout=3):
         return self.rxq.recv(timeout, self.sent_packets)
 
-    def close(self):
-        #self.rxq._proc.terminate()
-        pass
-
 
 def create_gratuitous_arp_request(src_mac, src_ip):
-    """Creates scapy representation of gratuitous ARP request"""
+    """Creates scapy representation of gratuitous ARP request."""
     return (Ether(src=src_mac, dst='ff:ff:ff:ff:ff:ff') /
             ARP(psrc=src_ip, hwsrc=src_mac, pdst=src_ip))
 
@@ -308,3 +297,25 @@ def auto_pad(packet):
         padded += ('\0' * (60 - len(padded)))
     return padded
 
+
+def checksum_equal(chksum1, chksum2):
+    """Compares two checksums in one's complement notation.
+
+    Checksums to be compared are calculated as 16 bit one's complement of the
+    one's complement sum of 16 bit words of some buffer.
+    In one's complement notation 0x0000 (positive zero) and 0xFFFF
+    (negative zero) are equivalent.
+
+    :param chksum1: First checksum.
+    :param chksum2: Second checksum.
+    :type chksum1: uint16
+    :type chksum2: uint16
+
+    :return: True if checksums are equivalent, False otherwise.
+    :rtype: boolean
+    """
+    if chksum1 == 0xFFFF:
+        chksum1 = 0
+    if chksum2 == 0xFFFF:
+        chksum2 = 0
+    return chksum1 == chksum2