packet.py 文件源码

def parse(self):
        """
        Update the headers in self.match based on self.data 

        Parses the relevant header features out of the packet, using
        the table outlined in the OF1.1 spec, Figure 4
        """
        self.bytes = len(self.data)
        self.match.in_port = self.in_port
        self.match.type = ofp.OFPMT_STANDARD
        self.match.length = ofp.OFPMT_STANDARD_LENGTH
        self.match.wildcards = 0
        self.match.nw_dst_mask = 0
        self.match.nw_dst_mask = 0
        self.match.dl_dst_mask = [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
        self.match.dl_src_mask = [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
        self.mpls_tag_offset = None
        self.ip_header_offset = None

        idx = 0
        try:
            idx = self._parse_l2(idx)

            if self.match.dl_type == ETHERTYPE_IP:
                self.ip_header_offset = idx 
                idx = self._parse_ip(idx)
                if self.match.nw_proto in [ socket.IPPROTO_TCP,
                                            socket.IPPROTO_UDP,
                                            socket.IPPROTO_ICMP]:
                    self.tcp_header_offset = idx
                    if self.match.nw_proto != socket.IPPROTO_ICMP:
                        idx = self._parse_l4(idx)
                    else:
                        idx = self._parse_icmp(idx)
            elif self.match.dl_type == ETHERTYPE_ARP:
                self._parse_arp(idx)
        except (parse_error), e:
            self.logger.warn("Giving up on parsing packet, got %s" % 
                             (str(e)))
            return None
        return self.match