| """ |
| OpenFlow Test Framework |
| |
| Controller class |
| |
| Provide the interface to the control channel to the switch under test. |
| |
| Class inherits from thread so as to run in background allowing |
| asynchronous callbacks (if needed, not required). Also supports |
| polling. |
| |
| The controller thread maintains a queue. Incoming messages that |
| are not handled by a callback function are placed in this queue for |
| poll calls. |
| |
| Callbacks and polling support specifying the message type |
| |
| @todo Support transaction semantics via xid |
| @todo Set up reasonable logging facility |
| @todo Support select and listen on an administrative socket (or |
| use a timeout to support clean shutdown). |
| |
| Currently only one connection is accepted during the life of |
| the controller. There seems |
| to be no clean way to interrupt an accept call. Using select that also listens |
| on an administrative socket and can shut down the socket might work. |
| |
| """ |
| |
| from oft_config import * |
| import os |
| import socket |
| import time |
| from threading import Thread |
| from threading import Lock |
| from threading import Condition |
| from message import * |
| from parse import * |
| from ofutils import * |
| |
| class Controller(Thread): |
| """ |
| Class abstracting the control interface to the switch. |
| |
| For receiving messages, two mechanism will be implemented. First, |
| query the interface with poll. Second, register to have a |
| function called by message type. The callback is passed the |
| message type as well as the raw packet (or message object) |
| |
| One of the main purposes of this object is to translate between network |
| and host byte order. 'Above' this object, things should be in host |
| byte order. |
| |
| @todo Consider using SocketServer for listening socket |
| @todo Test transaction code |
| |
| @var rcv_size The receive size to use for receive calls |
| @var max_pkts The max size of the receive queue |
| @var keep_alive If true, listen for echo requests and respond w/ |
| echo replies |
| @var host The host to use for connect |
| @var port The port to connect on |
| @var packets_total Total number of packets received |
| @var packets_expired Number of packets popped from queue as queue full |
| @var packets_handled Number of packets handled by something |
| @var dbg_state Debug indication of state |
| """ |
| |
| def __init__(self, max_pkts=1024): |
| Thread.__init__(self) |
| # Socket related |
| self.rcv_size = RCV_SIZE_DEFAULT |
| self.listen_socket = None |
| self.switch_socket = None |
| self.switch_addr = None |
| |
| # Counters |
| self.socket_errors = 0 |
| self.parse_errors = 0 |
| self.packets_total = 0 |
| self.packets_expired = 0 |
| self.packets_handled = 0 |
| |
| # State |
| self.connected = False |
| self.packets = [] |
| self.sync = Lock() |
| self.handlers = {} |
| self.keep_alive = False |
| |
| # Settings |
| self.max_pkts = max_pkts |
| self.passive = True |
| self.host = controller_host |
| self.port = controller_port |
| self.dbg_state = "init" |
| # self.debug_level = DEBUG_VERBOSE |
| self.debug_level = debug_level_default |
| |
| # Transaction variables |
| # xid_cv: Condition variable (semaphore) for transaction |
| # xid: Transaction ID being waited on |
| # xid_response: Transaction response message |
| self.xid_cv = Condition() |
| self.xid = None |
| self.xid_response = None |
| |
| def dbg(self, level, string): |
| debug_log("CTRL", self.debug_level, level, string) |
| |
| def run(self): |
| """ |
| Activity function for class |
| |
| Assumes connection to switch already exists. Listens on |
| switch_socket for messages until an error (or zero len pkt) |
| occurs. |
| |
| When there is a message on the socket, check for handlers; queue the |
| packet if no one handles the packet. |
| |
| See note for controller describing the limitation of a single |
| connection for now. |
| """ |
| |
| if not self.switch_socket: |
| self.dbg(DEBUG_ERROR, |
| "Error in controller thread, no switch socket") |
| self.shutdown() |
| return |
| |
| # Read and process packets from socket connected to switch |
| while 1: |
| try: |
| pkt = self.switch_socket.recv(self.rcv_size) |
| except socket.error: |
| self.dbg(DEBUG_ERROR, "Controller socket read error") |
| self.socket_errors += 1 |
| break |
| |
| if len(pkt) == 0: |
| # Considered an error; usually means switch has disconnected |
| self.dbg(DEBUG_INFO, "length 0 pkt in") |
| self.socket_errors += 1 |
| break |
| |
| if not self.connected: |
| break |
| |
| (handled, msg) = self._pkt_handler_check(pkt) |
| if handled: |
| self.packets_handled += 1 |
| continue |
| |
| # Not handled, enqueue |
| self.sync.acquire() |
| if len(self.packets) >= self.max_pkts: |
| self.packets.pop(0) |
| self.packets_expired += 1 |
| self.packets.append((msg, pkt)) |
| self.packets_total += 1 |
| self.sync.release() |
| |
| self.shutdown() |
| |
| def connect(self, send_hello=True): |
| """ |
| Connect to a switch and start this thread |
| |
| Create the listening socket, accept and block until a |
| connection is made to the switch. Then start the local |
| thread and return. Parameters to the call are take from |
| member variables. |
| |
| @param send_hello If True, send the initial hello packet on connection |
| @return Boolean where True indicates success |
| |
| If already connected, returns True |
| If the listen socket does not exist, will create it |
| """ |
| |
| self.dbg_state = "connecting" |
| self.dbg(DEBUG_INFO, "open ctl host: >" + str(self.host) + "< port " + |
| str(self.port)) |
| # Create the listening socket |
| if not self.listen_socket: |
| self.listen_socket = socket.socket(socket.AF_INET, |
| socket.SOCK_STREAM) |
| self.listen_socket.setsockopt(socket.SOL_SOCKET, |
| socket.SO_REUSEADDR, 1) |
| self.listen_socket.bind((self.host, self.port)) |
| self.dbg_state = "listening" |
| self.listen_socket.listen(LISTEN_QUEUE_SIZE) |
| self.dbg_state = "accepting" |
| (self.switch_socket, self.switch_addr) = self.listen_socket.accept() |
| if not self.switch_socket: |
| self.socket_errors += 1 |
| self.dbg(DEBUG_WARN, "Failed on accept") |
| self.dbg_state = "error" |
| self.listen_socket.close() |
| return False |
| |
| self.connected = True |
| self.dbg_state = "connected" |
| self.dbg(DEBUG_INFO, "Got connection to " + str(self.switch_addr)) |
| |
| if send_hello: |
| h = hello() |
| self.message_send(h.pack()) |
| |
| # Start the background thread |
| self.start() |
| |
| return True |
| |
| def shutdown(self): |
| """ |
| Shutdown the controller closing all sockets |
| |
| @todo Might want to synchronize shutdown with self.sync... |
| """ |
| self.connected = False |
| self.dbg_state = "closed" |
| if self.switch_socket: |
| try: |
| self.switch_socket.shutdown(socket.SHUT_RDWR) |
| except: |
| self.dbg(DEBUG_INFO, "Ignoring switch soc shutdown error") |
| self.switch_socket = None |
| |
| if self.listen_socket: |
| try: |
| self.listen_socket.shutdown(socket.SHUT_RDWR) |
| except: |
| self.dbg(DEBUG_INFO, "Ignoring listen soc shutdown error") |
| self.listen_socket = None |
| |
| def _pkt_handler_check(self, pkt): |
| """ |
| Check for packet handling before being enqueued |
| |
| This includes checking for an ongoing transaction (see transact()) |
| an echo request in case keep_alive is true, followed by |
| registered message handlers. |
| @param pkt The raw packet (string) |
| @return (handled, msg) where handled is a boolean indicating |
| the message was handled; msg if None is the parsed message |
| """ |
| # Parse the header to get type |
| hdr = of_header_parse(pkt) |
| if not hdr: |
| self.dbg(DEBUG_INFO, "Could not parse header, pkt len", len(pkt)) |
| self.parse_errors += 1 |
| return (True, None) |
| # if self.debug_level <= DEBUG_VERBOSE: |
| # hdr.show() |
| |
| self.dbg(DEBUG_VERBOSE, "message: len %d. type %s. hdr.len %d" % |
| (len(pkt), ofp_type_map[hdr.type], hdr.length)) |
| msg = of_message_parse(pkt) |
| if not msg: |
| self.parse_errors += 1 |
| self.dbg(DEBUG_WARN, "Could not parse message") |
| return (True, None) |
| |
| # Check if transaction is waiting |
| self.xid_cv.acquire() |
| if self.xid: |
| if hdr.xid == self.xid: |
| self.xid_response = msg |
| self.xid_cv.notify() |
| self.xid_cv.release() |
| return (True, None) |
| self.xid_cv.release() |
| |
| # Check if keep alive is set; if so, respond to echo requests |
| if self.keep_alive: |
| if hdr.type == OFPT_ECHO_REQUEST: |
| rep = echo_reply() |
| rep.header.xid = hdr.xid |
| # Ignoring additional data |
| self.message_send(rep.pack()) |
| return (True, None) |
| |
| # Now check for message handlers; preference is given to |
| # handlers for a specific packet |
| handled = False |
| if hdr.type in self.handlers.keys(): |
| handled = self.handlers[hdr.type](self, msg, pkt) |
| if not handled and ("all" in self.handlers.keys()): |
| handled = self.handlers["all"](self, msg, pkt) |
| |
| return (handled, msg) |
| |
| def register(self, msg_type, handler): |
| """ |
| Register a callback to receive a specific message type. |
| |
| Only one handler may be registered for a given message type. |
| @param msg_type The type of message to receive. May be DEFAULT |
| for all non-handled packets. The special type, the string "all" |
| will send all packets to the handler. |
| @param handler The function to call when a message of the given |
| type is received. |
| """ |
| # Should check type is valid |
| if not handler and msg_type in self.handlers.keys(): |
| del self.handlers[msg_type] |
| return |
| self.handlers[msg_type] = handler |
| |
| def poll(self, exp_msg=None, timeout=None): |
| """ |
| Wait for the next OF message received from the switch. |
| |
| @param exp_msg If set, return only when this type of message |
| is received. |
| @param timeout Not yet supported |
| |
| @retval A pair (msg, pkt) where msg is a message object and pkt |
| the string representing the packet as received from the socket. |
| This allows additional parsing by the receiver if necessary. |
| |
| The data members in the message are in host endian order. |
| If an error occurs, None is returned |
| """ |
| |
| # For now do not support time out; |
| if timeout: |
| self.dbg(DEBUG_WARN, "Poll time out not supported") |
| |
| while len(self.packets) > 0: |
| self.sync.acquire() |
| (msg, pkt) = self.packets.pop(0) |
| self.sync.release() |
| if not exp_msg or (exp_msg and (msg.header.type == exp_msg)): |
| return msg, pkt |
| |
| return None, None |
| |
| def transact(self, msg, timeout=None, zero_xid=False): |
| """ |
| Run a message transaction with the switch |
| |
| Send the message in msg and wait for a reply with a matching |
| transaction id. Transactions have the highest priority in |
| received message handling. |
| |
| @param msg The message object to send; must not be a string |
| @param timeout The timeout in seconds (?) |
| @param zero_xid Normally, if the XID is 0 an XID will be generated |
| for the message. Set xero_xid to override this behavior |
| @return The matching message object or None if unsuccessful |
| |
| """ |
| |
| if not zero_xid and msg.header.xid == 0: |
| msg.header.xid = gen_xid() |
| |
| self.xid_cv.acquire() |
| if self.xid: |
| self.xid_cv.release() |
| self.dbg(DEBUG_ERROR, |
| "Can only run one transaction at a time") |
| return None |
| |
| self.xid = msg.header.xid |
| self.xid_response = None |
| self.message_send(msg.pack()) |
| self.xid_cv.wait(timeout) |
| msg = self.xid_response |
| self.xid_response = None |
| self.xid_cv.release() |
| return msg |
| |
| def message_send(self, msg): |
| """ |
| Send the message to the switch |
| |
| @param msg An OpenFlow message object to be forwarded to the switch. |
| |
| @return None on success |
| |
| """ |
| |
| if not self.switch_socket: |
| # Sending a string indicates the message is ready to go |
| self.dbg(DEBUG_INFO, "message_send: no socket") |
| return -1 |
| |
| if type(msg) != type(""): |
| # Sending a string indicates the message is ready to go |
| self.dbg(DEBUG_INFO, "message_send requires packet as string") |
| return -1 |
| |
| self.dbg(DEBUG_INFO, "Sending pkt of len " + str(len(msg))) |
| return self.switch_socket.sendall(msg) |
| |
| def __str__(self): |
| string = "Controller:\n" |
| string += " connected " + str(self.connected) + "\n" |
| string += " state " + self.dbg_state + "\n" |
| string += " switch_addr " + str(self.switch_addr) + "\n" |
| string += " pending pkts " + str(len(self.packets)) + "\n" |
| string += " total pkts " + str(self.packets_total) + "\n" |
| string += " expired pkts " + str(self.packets_expired) + "\n" |
| string += " handled pkts " + str(self.packets_handled) + "\n" |
| string += " parse errors " + str(self.parse_errors) + "\n" |
| string += " sock errrors " + str(self.socket_errors) + "\n" |
| string += " max pkts " + str(self.max_pkts) + "\n" |
| string += " host " + str(self.host) + "\n" |
| string += " port " + str(self.port) + "\n" |
| string += " keep_alive " + str(self.keep_alive) + "\n" |
| return string |
| |
| def show(self): |
| print str(self) |
| |
| def sample_handler(controller, msg, pkt): |
| """ |
| Sample message handler |
| |
| This is the prototype for functions registered with the controller |
| class for packet reception |
| |
| @param controller The controller calling the handler |
| @param msg The parsed message object |
| @param pkt The raw packet that was received on the socket. This is |
| in case the packet contains extra unparsed data. |
| @returns Boolean value indicating if the packet was handled. If |
| not handled, the packet is placed in the queue for pollers to received |
| """ |
| pass |