lib/dpif-provider.h

   1 /*
   2  * Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef DPIF_PROVIDER_H
  18 #define DPIF_PROVIDER_H 1
  19
  20 /* Provider interface to dpifs, which provide an interface to an Open vSwitch
  21  * datapath.  A datapath is a collection of physical or virtual ports that are
  22  * exposed over OpenFlow as a single switch.  Datapaths and the collections of
  23  * ports that they contain may be fixed or dynamic. */
  24
  25 #include "openflow/openflow.h"
  26 #include "dpif.h"
  27 #include "util.h"
  28
  29 #ifdef  __cplusplus
  30 extern "C" {
  31 #endif
  32
  33 /* Open vSwitch datapath interface.
  34  *
  35  * This structure should be treated as opaque by dpif implementations. */
  36 struct dpif {
  37     const struct dpif_class *dpif_class;
  38     char *base_name;
  39     char *full_name;
  40     uint8_t netflow_engine_type;
  41     uint8_t netflow_engine_id;
  42 };
  43
  44 void dpif_init(struct dpif *, const struct dpif_class *, const char *name,
  45                uint8_t netflow_engine_type, uint8_t netflow_engine_id);
  46 void dpif_uninit(struct dpif *dpif, bool close);
  47
  48 static inline void dpif_assert_class(const struct dpif *dpif,
  49                                      const struct dpif_class *dpif_class)
  50 {
  51     ovs_assert(dpif->dpif_class == dpif_class);
  52 }
  53
  54 struct dpif_flow_dump {
  55     struct dpif *dpif;
  56     bool terse;         /* If true, key/mask/actions may be omitted. */
  57 };
  58
  59 static inline void
  60 dpif_flow_dump_init(struct dpif_flow_dump *dump, const struct dpif *dpif)
  61 {
  62     dump->dpif = CONST_CAST(struct dpif *, dpif);
  63 }
  64
  65 struct dpif_flow_dump_thread {
  66     struct dpif *dpif;
  67 };
  68
  69 static inline void
  70 dpif_flow_dump_thread_init(struct dpif_flow_dump_thread *thread,
  71                            struct dpif_flow_dump *dump)
  72 {
  73     thread->dpif = dump->dpif;
  74 }
  75
  76 struct ct_dpif_dump_state;
  77 struct ct_dpif_entry;
  78
  79 /* Datapath interface class structure, to be defined by each implementation of
  80  * a datapath interface.
  81  *
  82  * These functions return 0 if successful or a positive errno value on failure,
  83  * except where otherwise noted.
  84  *
  85  * These functions are expected to execute synchronously, that is, to block as
  86  * necessary to obtain a result.  Thus, they may not return EAGAIN or
  87  * EWOULDBLOCK or EINPROGRESS.  We may relax this requirement in the future if
  88  * and when we encounter performance problems. */
  89 struct dpif_class {
  90     /* Type of dpif in this class, e.g. "system", "netdev", etc.
  91      *
  92      * One of the providers should supply a "system" type, since this is
  93      * the type assumed if no type is specified when opening a dpif. */
  94     const char *type;
  95
  96     /* Called when the dpif provider is registered, typically at program
  97      * startup.  Returning an error from this function will prevent any
  98      * datapath with this class from being created.
  99      *
 100      * This function may be set to null if a datapath class needs no
 101      * initialization at registration time. */
 102     int (*init)(void);
 103
 104     /* Enumerates the names of all known created datapaths (of class
 105      * 'dpif_class'), if possible, into 'all_dps'.  The caller has already
 106      * initialized 'all_dps' and other dpif classes might already have added
 107      * names to it.
 108      *
 109      * This is used by the vswitch at startup, so that it can delete any
 110      * datapaths that are not configured.
 111      *
 112      * Some kinds of datapaths might not be practically enumerable, in which
 113      * case this function may be a null pointer. */
 114     int (*enumerate)(struct sset *all_dps, const struct dpif_class *dpif_class);
 115
 116     /* Returns the type to pass to netdev_open() when a dpif of class
 117      * 'dpif_class' has a port of type 'type', for a few special cases
 118      * when a netdev type differs from a port type.  For example, when
 119      * using the userspace datapath, a port of type "internal" needs to
 120      * be opened as "tap".
 121      *
 122      * Returns either 'type' itself or a string literal, which must not
 123      * be freed. */
 124     const char *(*port_open_type)(const struct dpif_class *dpif_class,
 125                                   const char *type);
 126
 127     /* Attempts to open an existing dpif called 'name', if 'create' is false,
 128      * or to open an existing dpif or create a new one, if 'create' is true.
 129      *
 130      * 'dpif_class' is the class of dpif to open.
 131      *
 132      * If successful, stores a pointer to the new dpif in '*dpifp', which must
 133      * have class 'dpif_class'.  On failure there are no requirements on what
 134      * is stored in '*dpifp'. */
 135     int (*open)(const struct dpif_class *dpif_class,
 136                 const char *name, bool create, struct dpif **dpifp);
 137
 138     /* Closes 'dpif' and frees associated memory. */
 139     void (*close)(struct dpif *dpif);
 140
 141     /* Attempts to destroy the dpif underlying 'dpif'.
 142      *
 143      * If successful, 'dpif' will not be used again except as an argument for
 144      * the 'close' member function. */
 145     int (*destroy)(struct dpif *dpif);
 146
 147     /* Performs periodic work needed by 'dpif', if any is necessary.
 148      * Returns true if need to revalidate. */
 149     bool (*run)(struct dpif *dpif);
 150
 151     /* Arranges for poll_block() to wake up if the "run" member function needs
 152      * to be called for 'dpif'. */
 153     void (*wait)(struct dpif *dpif);
 154
 155     /* Retrieves statistics for 'dpif' into 'stats'. */
 156     int (*get_stats)(const struct dpif *dpif, struct dpif_dp_stats *stats);
 157
 158     /* Adds 'netdev' as a new port in 'dpif'.  If '*port_no' is not
 159      * ODPP_NONE, attempts to use that as the port's port number.
 160      *
 161      * If port is successfully added, sets '*port_no' to the new port's
 162      * port number.  Returns EBUSY if caller attempted to choose a port
 163      * number, and it was in use. */
 164     int (*port_add)(struct dpif *dpif, struct netdev *netdev,
 165                     odp_port_t *port_no);
 166
 167     /* Removes port numbered 'port_no' from 'dpif'. */
 168     int (*port_del)(struct dpif *dpif, odp_port_t port_no);
 169
 170     /* Refreshes configuration of 'dpif's port. The implementation might
 171      * postpone applying the changes until run() is called. */
 172     int (*port_set_config)(struct dpif *dpif, odp_port_t port_no,
 173                            const struct smap *cfg);
 174
 175     /* Queries 'dpif' for a port with the given 'port_no' or 'devname'.
 176      * If 'port' is not null, stores information about the port into
 177      * '*port' if successful.
 178      *
 179      * If the port doesn't exist, the provider must return ENODEV.  Other
 180      * error numbers means that something wrong happened and will be
 181      * treated differently by upper layers.
 182      *
 183      * If 'port' is not null, the caller takes ownership of data in
 184      * 'port' and must free it with dpif_port_destroy() when it is no
 185      * longer needed. */
 186     int (*port_query_by_number)(const struct dpif *dpif, odp_port_t port_no,
 187                                 struct dpif_port *port);
 188     int (*port_query_by_name)(const struct dpif *dpif, const char *devname,
 189                               struct dpif_port *port);
 190
 191     /* Returns the Netlink PID value to supply in OVS_ACTION_ATTR_USERSPACE
 192      * actions as the OVS_USERSPACE_ATTR_PID attribute's value, for use in
 193      * flows whose packets arrived on port 'port_no'.  In the case where the
 194      * provider allocates multiple Netlink PIDs to a single port, it may use
 195      * 'hash' to spread load among them.  The caller need not use a particular
 196      * hash function; a 5-tuple hash is suitable.
 197      *
 198      * (The datapath implementation might use some different hash function for
 199      * distributing packets received via flow misses among PIDs.  This means
 200      * that packets received via flow misses might be reordered relative to
 201      * packets received via userspace actions.  This is not ordinarily a
 202      * problem.)
 203      *
 204      * A 'port_no' of UINT32_MAX should be treated as a special case.  The
 205      * implementation should return a reserved PID, not allocated to any port,
 206      * that the client may use for special purposes.
 207      *
 208      * The return value only needs to be meaningful when DPIF_UC_ACTION has
 209      * been enabled in the 'dpif''s listen mask, and it is allowed to change
 210      * when DPIF_UC_ACTION is disabled and then re-enabled.
 211      *
 212      * A dpif provider that doesn't have meaningful Netlink PIDs can use NULL
 213      * for this function.  This is equivalent to always returning 0. */
 214     uint32_t (*port_get_pid)(const struct dpif *dpif, odp_port_t port_no,
 215                              uint32_t hash);
 216
 217     /* Attempts to begin dumping the ports in a dpif.  On success, returns 0
 218      * and initializes '*statep' with any data needed for iteration.  On
 219      * failure, returns a positive errno value. */
 220     int (*port_dump_start)(const struct dpif *dpif, void **statep);
 221
 222     /* Attempts to retrieve another port from 'dpif' for 'state', which was
 223      * initialized by a successful call to the 'port_dump_start' function for
 224      * 'dpif'.  On success, stores a new dpif_port into 'port' and returns 0.
 225      * Returns EOF if the end of the port table has been reached, or a positive
 226      * errno value on error.  This function will not be called again once it
 227      * returns nonzero once for a given iteration (but the 'port_dump_done'
 228      * function will be called afterward).
 229      *
 230      * The dpif provider retains ownership of the data stored in 'port'.  It
 231      * must remain valid until at least the next call to 'port_dump_next' or
 232      * 'port_dump_done' for 'state'. */
 233     int (*port_dump_next)(const struct dpif *dpif, void *state,
 234                           struct dpif_port *port);
 235
 236     /* Releases resources from 'dpif' for 'state', which was initialized by a
 237      * successful call to the 'port_dump_start' function for 'dpif'.  */
 238     int (*port_dump_done)(const struct dpif *dpif, void *state);
 239
 240     /* Polls for changes in the set of ports in 'dpif'.  If the set of ports in
 241      * 'dpif' has changed, then this function should do one of the
 242      * following:
 243      *
 244      * - Preferably: store the name of the device that was added to or deleted
 245      *   from 'dpif' in '*devnamep' and return 0.  The caller is responsible
 246      *   for freeing '*devnamep' (with free()) when it no longer needs it.
 247      *
 248      * - Alternatively: return ENOBUFS, without indicating the device that was
 249      *   added or deleted.
 250      *
 251      * Occasional 'false positives', in which the function returns 0 while
 252      * indicating a device that was not actually added or deleted or returns
 253      * ENOBUFS without any change, are acceptable.
 254      *
 255      * If the set of ports in 'dpif' has not changed, returns EAGAIN.  May also
 256      * return other positive errno values to indicate that something has gone
 257      * wrong. */
 258     int (*port_poll)(const struct dpif *dpif, char **devnamep);
 259
 260     /* Arranges for the poll loop to wake up when 'port_poll' will return a
 261      * value other than EAGAIN. */
 262     void (*port_poll_wait)(const struct dpif *dpif);
 263
 264     /* Deletes all flows from 'dpif' and clears all of its queues of received
 265      * packets. */
 266     int (*flow_flush)(struct dpif *dpif);
 267
 268     /* Flow dumping interface.
 269      *
 270      * This is the back-end for the flow dumping interface described in
 271      * dpif.h.  Please read the comments there first, because this code
 272      * closely follows it.
 273      *
 274      * 'flow_dump_create' and 'flow_dump_thread_create' must always return an
 275      * initialized and usable data structure and defer error return until
 276      * flow_dump_destroy().  This hasn't been a problem for the dpifs that
 277      * exist so far.
 278      *
 279      * 'flow_dump_create' and 'flow_dump_thread_create' must initialize the
 280      * structures that they return with dpif_flow_dump_init() and
 281      * dpif_flow_dump_thread_init(), respectively.
 282      *
 283      * If 'terse' is true, then only UID and statistics will
 284      * be returned in the dump. Otherwise, all fields will be returned. */
 285     struct dpif_flow_dump *(*flow_dump_create)(const struct dpif *dpif,
 286                                                bool terse);
 287     int (*flow_dump_destroy)(struct dpif_flow_dump *dump);
 288
 289     struct dpif_flow_dump_thread *(*flow_dump_thread_create)(
 290         struct dpif_flow_dump *dump);
 291     void (*flow_dump_thread_destroy)(struct dpif_flow_dump_thread *thread);
 292
 293     int (*flow_dump_next)(struct dpif_flow_dump_thread *thread,
 294                           struct dpif_flow *flows, int max_flows);
 295
 296     /* Executes each of the 'n_ops' operations in 'ops' on 'dpif', in the order
 297      * in which they are specified, placing each operation's results in the
 298      * "output" members documented in comments and the 'error' member of each
 299      * dpif_op. */
 300     void (*operate)(struct dpif *dpif, struct dpif_op **ops, size_t n_ops);
 301
 302     /* Enables or disables receiving packets with dpif_recv() for 'dpif'.
 303      * Turning packet receive off and then back on is allowed to change Netlink
 304      * PID assignments (see ->port_get_pid()).  The client is responsible for
 305      * updating flows as necessary if it does this. */
 306     int (*recv_set)(struct dpif *dpif, bool enable);
 307
 308     /* Refreshes the poll loops and Netlink sockets associated to each port,
 309      * when the number of upcall handlers (upcall receiving thread) is changed
 310      * to 'n_handlers' and receiving packets for 'dpif' is enabled by
 311      * recv_set().
 312      *
 313      * Since multiple upcall handlers can read upcalls simultaneously from
 314      * 'dpif', each port can have multiple Netlink sockets, one per upcall
 315      * handler.  So, handlers_set() is responsible for the following tasks:
 316      *
 317      *    When receiving upcall is enabled, extends or creates the
 318      *    configuration to support:
 319      *
 320      *        - 'n_handlers' Netlink sockets for each port.
 321      *
 322      *        - 'n_handlers' poll loops, one for each upcall handler.
 323      *
 324      *        - registering the Netlink sockets for the same upcall handler to
 325      *          the corresponding poll loop.
 326      * */
 327     int (*handlers_set)(struct dpif *dpif, uint32_t n_handlers);
 328
 329     /* If 'dpif' creates its own I/O polling threads, refreshes poll threads
 330      * configuration.  'cmask' configures the cpu mask for setting the polling
 331      * threads' cpu affinity.  The implementation might postpone applying the
 332      * changes until run() is called. */
 333     int (*poll_threads_set)(struct dpif *dpif, const char *cmask);
 334
 335     /* Translates OpenFlow queue ID 'queue_id' (in host byte order) into a
 336      * priority value used for setting packet priority. */
 337     int (*queue_to_priority)(const struct dpif *dpif, uint32_t queue_id,
 338                              uint32_t *priority);
 339
 340     /* Polls for an upcall from 'dpif' for an upcall handler.  Since there
 341      * can be multiple poll loops (see ->handlers_set()), 'handler_id' is
 342      * needed as index to identify the corresponding poll loop.  If
 343      * successful, stores the upcall into '*upcall', using 'buf' for
 344      * storage.  Should only be called if 'recv_set' has been used to enable
 345      * receiving packets from 'dpif'.
 346      *
 347      * The implementation should point 'upcall->key' and 'upcall->userdata'
 348      * (if any) into data in the caller-provided 'buf'.  The implementation may
 349      * also use 'buf' for storing the data of 'upcall->packet'.  If necessary
 350      * to make room, the implementation may reallocate the data in 'buf'.
 351      *
 352      * The caller owns the data of 'upcall->packet' and may modify it.  If
 353      * packet's headroom is exhausted as it is manipulated, 'upcall->packet'
 354      * will be reallocated.  This requires the data of 'upcall->packet' to be
 355      * released with ofpbuf_uninit() before 'upcall' is destroyed.  However,
 356      * when an error is returned, the 'upcall->packet' may be uninitialized
 357      * and should not be released.
 358      *
 359      * This function must not block.  If no upcall is pending when it is
 360      * called, it should return EAGAIN without blocking. */
 361     int (*recv)(struct dpif *dpif, uint32_t handler_id,
 362                 struct dpif_upcall *upcall, struct ofpbuf *buf);
 363
 364     /* Arranges for the poll loop for an upcall handler to wake up when 'dpif'
 365      * has a message queued to be received with the recv member functions.
 366      * Since there can be multiple poll loops (see ->handlers_set()),
 367      * 'handler_id' is needed as index to identify the corresponding poll loop.
 368      * */
 369     void (*recv_wait)(struct dpif *dpif, uint32_t handler_id);
 370
 371     /* Throws away any queued upcalls that 'dpif' currently has ready to
 372      * return. */
 373     void (*recv_purge)(struct dpif *dpif);
 374
 375     /* When 'dpif' is about to purge the datapath, the higher layer may want
 376      * to be notified so that it could try reacting accordingly (e.g. grabbing
 377      * all flow stats before they are gone).
 378      *
 379      * Registers an upcall callback function with 'dpif'.  This is only used
 380      * if 'dpif' needs to notify the purging of datapath.  'aux' is passed to
 381      * the callback on invocation. */
 382     void (*register_dp_purge_cb)(struct dpif *, dp_purge_callback *, void *aux);
 383
 384     /* For datapaths that run in userspace (i.e. dpif-netdev), threads polling
 385      * for incoming packets can directly call upcall functions instead of
 386      * offloading packet processing to separate handler threads. Datapaths
 387      * that directly call upcall functions should use the functions below to
 388      * to register an upcall function and enable / disable upcalls.
 389      *
 390      * Registers an upcall callback function with 'dpif'. This is only used
 391      * if 'dpif' directly executes upcall functions. 'aux' is passed to the
 392      * callback on invocation. */
 393     void (*register_upcall_cb)(struct dpif *, upcall_callback *, void *aux);
 394
 395     /* Enables upcalls if 'dpif' directly executes upcall functions. */
 396     void (*enable_upcall)(struct dpif *);
 397
 398     /* Disables upcalls if 'dpif' directly executes upcall functions. */
 399     void (*disable_upcall)(struct dpif *);
 400
 401     /* Get datapath version. Caller is responsible for freeing the string
 402      * returned.  */
 403     char *(*get_datapath_version)(void);
 404
 405     /* Conntrack entry dumping interface.
 406      *
 407      * These functions are used by ct-dpif.c to provide a datapath-agnostic
 408      * dumping interface to the connection trackers provided by the
 409      * datapaths.
 410      *
 411      * ct_dump_start() should put in '*state' a pointer to a newly allocated
 412      * stucture that will be passed by the caller to ct_dump_next() and
 413      * ct_dump_done(). If 'zone' is not NULL, only the entries in '*zone'
 414      * should be dumped.
 415      *
 416      * ct_dump_next() should fill 'entry' with information from a connection
 417      * and prepare to dump the next one on a subsequest invocation.
 418      *
 419      * ct_dump_done() should perform any cleanup necessary (including
 420      * deallocating the 'state' structure, if applicable). */
 421     int (*ct_dump_start)(struct dpif *, struct ct_dpif_dump_state **state,
 422                          const uint16_t *zone);
 423     int (*ct_dump_next)(struct dpif *, struct ct_dpif_dump_state *state,
 424                         struct ct_dpif_entry *entry);
 425     int (*ct_dump_done)(struct dpif *, struct ct_dpif_dump_state *state);
 426
 427     /* Flushes the connection tracking tables. If 'zone' is not NULL,
 428      * only deletes connections in '*zone'. */
 429     int (*ct_flush)(struct dpif *, const uint16_t *zone);
 430 };
 431
 432 extern const struct dpif_class dpif_netlink_class;
 433 extern const struct dpif_class dpif_netdev_class;
 434
 435 #ifdef  __cplusplus
 436 }
 437 #endif
 438
 439 #endif /* dpif-provider.h */