Class PacketList

scapy/plist.py:741–779

class PacketList(_PacketList[Packet],
                 BasePacketList[Packet],
                 _CanvasDumpExtended):
    def sr(self, multi=False, lookahead=None):
        # type: (bool, Optional[int]) -> Tuple[SndRcvList, PacketList]
        """
        Matches packets in the list

        :param multi: True if a packet can have multiple answers
        :param lookahead: Maximum number of packets between packet and answer.
                          If 0 or None, full remaining list is
                          scanned for answers
        :return: ( (matched couples), (unmatched packets) )
        """
        remain = self.res[:]
        sr = []  # type: List[QueryAnswer]
        i = 0
        if lookahead is None or lookahead == 0:
            lookahead = len(remain)
        while i < len(remain):
            s = remain[i]
            j = i
            while j < min(lookahead + i, len(remain) - 1):
                j += 1
                r = remain[j]
                if r.answers(s):
                    sr.append(QueryAnswer(s, r))
                    if multi:
                        remain[i]._answered = 1
                        remain[j]._answered = 2
                        continue
                    del remain[j]
                    del remain[i]
                    i -= 1
                    break
            i += 1
        if multi:
            remain = [x for x in remain if not hasattr(x, "_answered")]
        return SndRcvList(sr), PacketList(remain)


_PacketIterable = Union[