| """ |
| OpenFlow message parsing functions |
| """ |
| |
| import logging |
| import message |
| import cstruct as ofp |
| |
| """ |
| of_message.py |
| Contains wrapper functions and classes for the of_message namespace |
| that are generated by hand. It includes the rest of the wrapper |
| function information into the of_message namespace |
| """ |
| |
| parse_logger = logging.getLogger("parse") |
| #parse_logger.setLevel(logging.DEBUG) |
| |
| # These message types are subclassed |
| msg_type_subclassed = [ |
| ofp.OFPT_STATS_REQUEST, |
| ofp.OFPT_STATS_REPLY, |
| ofp.OFPT_ERROR |
| ] |
| |
| # Maps from sub-types to classes |
| stats_reply_to_class_map = { |
| ofp.OFPST_DESC : message.desc_stats_reply, |
| ofp.OFPST_AGGREGATE : message.aggregate_stats_reply, |
| ofp.OFPST_FLOW : message.flow_stats_reply, |
| ofp.OFPST_TABLE : message.table_stats_reply, |
| ofp.OFPST_PORT : message.port_stats_reply, |
| ofp.OFPST_QUEUE : message.queue_stats_reply |
| } |
| |
| stats_request_to_class_map = { |
| ofp.OFPST_DESC : message.desc_stats_request, |
| ofp.OFPST_AGGREGATE : message.aggregate_stats_request, |
| ofp.OFPST_FLOW : message.flow_stats_request, |
| ofp.OFPST_TABLE : message.table_stats_request, |
| ofp.OFPST_PORT : message.port_stats_request, |
| ofp.OFPST_QUEUE : message.queue_stats_request |
| } |
| |
| error_to_class_map = { |
| ofp.OFPET_HELLO_FAILED : message.hello_failed_error_msg, |
| ofp.OFPET_BAD_REQUEST : message.bad_request_error_msg, |
| ofp.OFPET_BAD_ACTION : message.bad_action_error_msg, |
| ofp.OFPET_FLOW_MOD_FAILED : message.flow_mod_failed_error_msg, |
| ofp.OFPET_PORT_MOD_FAILED : message.port_mod_failed_error_msg, |
| ofp.OFPET_QUEUE_OP_FAILED : message.queue_op_failed_error_msg, |
| ofp.OFPET_TABLE_MOD_FAILED : message.table_mod_failed_error_msg, |
| ofp.OFPET_QUEUE_OP_FAILED : message.queue_op_failed_error_msg, |
| ofp.OFPET_SWITCH_CONFIG_FAILED : message.switch_config_failed_error_msg |
| } |
| |
| # Map from header type value to the underlieing message class |
| msg_type_to_class_map = { |
| ofp.OFPT_HELLO : message.hello, |
| ofp.OFPT_ERROR : message.error, |
| ofp.OFPT_ECHO_REQUEST : message.echo_request, |
| ofp.OFPT_ECHO_REPLY : message.echo_reply, |
| ofp.OFPT_EXPERIMENTER : message.experimenter, |
| ofp.OFPT_FEATURES_REQUEST : message.features_request, |
| ofp.OFPT_FEATURES_REPLY : message.features_reply, |
| ofp.OFPT_GET_CONFIG_REQUEST : message.get_config_request, |
| ofp.OFPT_GET_CONFIG_REPLY : message.get_config_reply, |
| ofp.OFPT_SET_CONFIG : message.set_config, |
| ofp.OFPT_PACKET_IN : message.packet_in, |
| ofp.OFPT_FLOW_REMOVED : message.flow_removed, |
| ofp.OFPT_PORT_STATUS : message.port_status, |
| ofp.OFPT_PACKET_OUT : message.packet_out, |
| ofp.OFPT_FLOW_MOD : message.flow_mod, |
| ofp.OFPT_PORT_MOD : message.port_mod, |
| ofp.OFPT_TABLE_MOD : message.table_mod, |
| ofp.OFPT_STATS_REQUEST : message.stats_request, |
| ofp.OFPT_STATS_REPLY : message.stats_reply, |
| ofp.OFPT_BARRIER_REQUEST : message.barrier_request, |
| ofp.OFPT_BARRIER_REPLY : message.barrier_reply, |
| ofp.OFPT_QUEUE_GET_CONFIG_REQUEST : message.queue_get_config_request, |
| ofp.OFPT_QUEUE_GET_CONFIG_REPLY : message.queue_get_config_reply, |
| } |
| |
| def _of_message_to_object(binary_string): |
| """ |
| Map a binary string to the corresponding class. |
| |
| Appropriately resolves subclasses |
| """ |
| hdr = ofp.ofp_header() |
| hdr.unpack(binary_string) |
| # FIXME: Add error detection |
| if not hdr.type in msg_type_subclassed: |
| return msg_type_to_class_map[hdr.type]() |
| if hdr.type == ofp.OFPT_STATS_REQUEST: |
| sub_hdr = ofp.ofp_stats_request() |
| sub_hdr.unpack(binary_string[ofp.OFP_HEADER_BYTES:]) |
| try: |
| obj = stats_request_to_class_map[sub_hdr.type]() |
| except LookupError: |
| obj = None |
| return obj |
| elif hdr.type == ofp.OFPT_STATS_REPLY: |
| sub_hdr = ofp.ofp_stats_reply() |
| sub_hdr.unpack(binary_string[ofp.OFP_HEADER_BYTES:]) |
| try: |
| obj = stats_reply_to_class_map[sub_hdr.type]() |
| except LookupError: |
| obj = None |
| return obj |
| elif hdr.type == ofp.OFPT_ERROR: |
| sub_hdr = ofp.ofp_error_msg() |
| sub_hdr.unpack(binary_string[ofp.OFP_HEADER_BYTES:]) |
| return error_to_class_map[sub_hdr.type]() |
| else: |
| parse_logger.error("Cannot parse pkt to message") |
| return None |
| |
| def of_message_parse(binary_string, raw=False): |
| """ |
| Parse an OpenFlow packet |
| |
| Parses a raw OpenFlow packet into a Python class, with class |
| members fully populated. |
| |
| @param binary_string The packet (string) to be parsed |
| @param raw If true, interpret the packet as an L2 packet. Not |
| yet supported. |
| @return An object of some message class or None if fails |
| Note that any data beyond that parsed is not returned |
| |
| """ |
| |
| if raw: |
| parse_logger.error("raw packet message parsing not supported") |
| return None |
| |
| obj = _of_message_to_object(binary_string) |
| if obj: |
| obj.unpack(binary_string) |
| return obj |
| |
| |
| def of_header_parse(binary_string, raw=False): |
| """ |
| Parse only the header from an OpenFlow packet |
| |
| Parses the header from a raw OpenFlow packet into a |
| an ofp_header Python class. |
| |
| @param binary_string The packet (string) to be parsed |
| @param raw If true, interpret the packet as an L2 packet. Not |
| yet supported. |
| @return An ofp_header object |
| |
| """ |
| |
| if raw: |
| parse_logger.error("raw packet message parsing not supported") |
| return None |
| |
| hdr = ofp.ofp_header() |
| hdr.unpack(binary_string) |
| |
| return hdr |
| |
| map_wc_field_to_match_member = { |
| 'OFPFW_DL_VLAN' : 'dl_vlan', |
| 'OFPFW_DL_SRC' : 'dl_src', |
| 'OFPFW_DL_DST' : 'dl_dst', |
| 'OFPFW_DL_TYPE' : 'dl_type', |
| 'OFPFW_NW_PROTO' : 'nw_proto', |
| 'OFPFW_TP_SRC' : 'tp_src', |
| 'OFPFW_TP_DST' : 'tp_dst', |
| 'OFPFW_NW_SRC_SHIFT' : 'nw_src_shift', |
| 'OFPFW_NW_SRC_BITS' : 'nw_src_bits', |
| 'OFPFW_NW_SRC_MASK' : 'nw_src_mask', |
| 'OFPFW_NW_SRC_ALL' : 'nw_src_all', |
| 'OFPFW_NW_DST_SHIFT' : 'nw_dst_shift', |
| 'OFPFW_NW_DST_BITS' : 'nw_dst_bits', |
| 'OFPFW_NW_DST_MASK' : 'nw_dst_mask', |
| 'OFPFW_NW_DST_ALL' : 'nw_dst_all', |
| 'OFPFW_DL_VLAN_PCP' : 'dl_vlan_pcp', |
| 'OFPFW_NW_TOS' : 'nw_tos' |
| } |
| |
| |
| def parse_mac(mac_str): |
| """ |
| Parse a MAC address |
| |
| Parse a MAC address ':' separated string of hex digits to an |
| array of integer values. '00:d0:05:5d:24:00' => [0, 208, 5, 93, 36, 0] |
| @param mac_str The string to convert |
| @return Array of 6 integer values |
| """ |
| return map(lambda val:eval("0x" + val), mac_str.split(":")) |
| |
| def parse_ip(ip_str): |
| """ |
| Parse an IP address |
| |
| Parse an IP address '.' separated string of decimal digits to an |
| host ordered integer. '172.24.74.77' => |
| @param ip_str The string to convert |
| @return Integer value |
| """ |
| array = map(lambda val:eval(val),ip_str.split(".")) |
| val = 0 |
| for a in array: |
| val <<= 8 |
| val += a |
| return val |
| |
| def packet_to_flow_match(packet): |
| """ |
| Create a flow match that matches packet with the given wildcards |
| |
| @param packet The packet to use as a flow template |
| @param pkt_format Currently only L2 is supported. Will indicate the |
| overall packet type for parsing |
| @return An ofp_match object if successful. None if format is not |
| recognized. The wildcards of the match will be cleared for the |
| values extracted from the packet. |
| |
| @todo check min length of packet |
| @todo Check if packet is other than L2 format |
| @todo Implement ICMP and ARP fields |
| """ |
| |
| return packet.parse() |