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 struct ct_dpif_tuple;
  79
  80 /* Datapath interface class structure, to be defined by each implementation of
  81  * a datapath interface.
  82  *
  83  * These functions return 0 if successful or a positive errno value on failure,
  84  * except where otherwise noted.
  85  *
  86  * These functions are expected to execute synchronously, that is, to block as
  87  * necessary to obtain a result.  Thus, they may not return EAGAIN or
  88  * EWOULDBLOCK or EINPROGRESS.  We may relax this requirement in the future if
  89  * and when we encounter performance problems. */
  90 struct dpif_class {
  91     /* Type of dpif in this class, e.g. "system", "netdev", etc.
  92      *
  93      * One of the providers should supply a "system" type, since this is
  94      * the type assumed if no type is specified when opening a dpif. */
  95     const char *type;
  96
  97     /* Called when the dpif provider is registered, typically at program
  98      * startup.  Returning an error from this function will prevent any
  99      * datapath with this class from being created.
 100      *
 101      * This function may be set to null if a datapath class needs no
 102      * initialization at registration time. */
 103     int (*init)(void);
 104
 105     /* Enumerates the names of all known created datapaths (of class
 106      * 'dpif_class'), if possible, into 'all_dps'.  The caller has already
 107      * initialized 'all_dps' and other dpif classes might already have added
 108      * names to it.
 109      *
 110      * This is used by the vswitch at startup, so that it can delete any
 111      * datapaths that are not configured.
 112      *
 113      * Some kinds of datapaths might not be practically enumerable, in which
 114      * case this function may be a null pointer. */
 115     int (*enumerate)(struct sset *all_dps, const struct dpif_class *dpif_class);
 116
 117     /* Returns the type to pass to netdev_open() when a dpif of class
 118      * 'dpif_class' has a port of type 'type', for a few special cases
 119      * when a netdev type differs from a port type.  For example, when
 120      * using the userspace datapath, a port of type "internal" needs to
 121      * be opened as "tap".
 122      *
 123      * Returns either 'type' itself or a string literal, which must not
 124      * be freed. */
 125     const char *(*port_open_type)(const struct dpif_class *dpif_class,
 126                                   const char *type);
 127
 128     /* Attempts to open an existing dpif called 'name', if 'create' is false,
 129      * or to open an existing dpif or create a new one, if 'create' is true.
 130      *
 131      * 'dpif_class' is the class of dpif to open.
 132      *
 133      * If successful, stores a pointer to the new dpif in '*dpifp', which must
 134      * have class 'dpif_class'.  On failure there are no requirements on what
 135      * is stored in '*dpifp'. */
 136     int (*open)(const struct dpif_class *dpif_class,
 137                 const char *name, bool create, struct dpif **dpifp);
 138
 139     /* Closes 'dpif' and frees associated memory. */
 140     void (*close)(struct dpif *dpif);
 141
 142     /* Attempts to destroy the dpif underlying 'dpif'.
 143      *
 144      * If successful, 'dpif' will not be used again except as an argument for
 145      * the 'close' member function. */
 146     int (*destroy)(struct dpif *dpif);
 147
 148     /* Performs periodic work needed by 'dpif', if any is necessary.
 149      * Returns true if need to revalidate. */
 150     bool (*run)(struct dpif *dpif);
 151
 152     /* Arranges for poll_block() to wake up if the "run" member function needs
 153      * to be called for 'dpif'. */
 154     void (*wait)(struct dpif *dpif);
 155
 156     /* Retrieves statistics for 'dpif' into 'stats'. */
 157     int (*get_stats)(const struct dpif *dpif, struct dpif_dp_stats *stats);
 158
 159     /* Adds 'netdev' as a new port in 'dpif'.  If '*port_no' is not
 160      * ODPP_NONE, attempts to use that as the port's port number.
 161      *
 162      * If port is successfully added, sets '*port_no' to the new port's
 163      * port number.  Returns EBUSY if caller attempted to choose a port
 164      * number, and it was in use. */
 165     int (*port_add)(struct dpif *dpif, struct netdev *netdev,
 166                     odp_port_t *port_no);
 167
 168     /* Removes port numbered 'port_no' from 'dpif'. */
 169     int (*port_del)(struct dpif *dpif, odp_port_t port_no);
 170
 171     /* Refreshes configuration of 'dpif's port. The implementation might
 172      * postpone applying the changes until run() is called. */
 173     int (*port_set_config)(struct dpif *dpif, odp_port_t port_no,
 174                            const struct smap *cfg);
 175
 176     /* Queries 'dpif' for a port with the given 'port_no' or 'devname'.
 177      * If 'port' is not null, stores information about the port into
 178      * '*port' if successful.
 179      *
 180      * If the port doesn't exist, the provider must return ENODEV.  Other
 181      * error numbers means that something wrong happened and will be
 182      * treated differently by upper layers.
 183      *
 184      * If 'port' is not null, the caller takes ownership of data in
 185      * 'port' and must free it with dpif_port_destroy() when it is no
 186      * longer needed. */
 187     int (*port_query_by_number)(const struct dpif *dpif, odp_port_t port_no,
 188                                 struct dpif_port *port);
 189     int (*port_query_by_name)(const struct dpif *dpif, const char *devname,
 190                               struct dpif_port *port);
 191
 192     /* Returns the Netlink PID value to supply in OVS_ACTION_ATTR_USERSPACE
 193      * actions as the OVS_USERSPACE_ATTR_PID attribute's value, for use in
 194      * flows whose packets arrived on port 'port_no'.  In the case where the
 195      * provider allocates multiple Netlink PIDs to a single port, it may use
 196      * 'hash' to spread load among them.  The caller need not use a particular
 197      * hash function; a 5-tuple hash is suitable.
 198      *
 199      * (The datapath implementation might use some different hash function for
 200      * distributing packets received via flow misses among PIDs.  This means
 201      * that packets received via flow misses might be reordered relative to
 202      * packets received via userspace actions.  This is not ordinarily a
 203      * problem.)
 204      *
 205      * A 'port_no' of UINT32_MAX should be treated as a special case.  The
 206      * implementation should return a reserved PID, not allocated to any port,
 207      * that the client may use for special purposes.
 208      *
 209      * The return value only needs to be meaningful when DPIF_UC_ACTION has
 210      * been enabled in the 'dpif''s listen mask, and it is allowed to change
 211      * when DPIF_UC_ACTION is disabled and then re-enabled.
 212      *
 213      * A dpif provider that doesn't have meaningful Netlink PIDs can use NULL
 214      * for this function.  This is equivalent to always returning 0. */
 215     uint32_t (*port_get_pid)(const struct dpif *dpif, odp_port_t port_no,
 216                              uint32_t hash);
 217
 218     /* Attempts to begin dumping the ports in a dpif.  On success, returns 0
 219      * and initializes '*statep' with any data needed for iteration.  On
 220      * failure, returns a positive errno value. */
 221     int (*port_dump_start)(const struct dpif *dpif, void **statep);
 222
 223     /* Attempts to retrieve another port from 'dpif' for 'state', which was
 224      * initialized by a successful call to the 'port_dump_start' function for
 225      * 'dpif'.  On success, stores a new dpif_port into 'port' and returns 0.
 226      * Returns EOF if the end of the port table has been reached, or a positive
 227      * errno value on error.  This function will not be called again once it
 228      * returns nonzero once for a given iteration (but the 'port_dump_done'
 229      * function will be called afterward).
 230      *
 231      * The dpif provider retains ownership of the data stored in 'port'.  It
 232      * must remain valid until at least the next call to 'port_dump_next' or
 233      * 'port_dump_done' for 'state'. */
 234     int (*port_dump_next)(const struct dpif *dpif, void *state,
 235                           struct dpif_port *port);
 236
 237     /* Releases resources from 'dpif' for 'state', which was initialized by a
 238      * successful call to the 'port_dump_start' function for 'dpif'.  */
 239     int (*port_dump_done)(const struct dpif *dpif, void *state);
 240
 241     /* Polls for changes in the set of ports in 'dpif'.  If the set of ports in
 242      * 'dpif' has changed, then this function should do one of the
 243      * following:
 244      *
 245      * - Preferably: store the name of the device that was added to or deleted
 246      *   from 'dpif' in '*devnamep' and return 0.  The caller is responsible
 247      *   for freeing '*devnamep' (with free()) when it no longer needs it.
 248      *
 249      * - Alternatively: return ENOBUFS, without indicating the device that was
 250      *   added or deleted.
 251      *
 252      * Occasional 'false positives', in which the function returns 0 while
 253      * indicating a device that was not actually added or deleted or returns
 254      * ENOBUFS without any change, are acceptable.
 255      *
 256      * If the set of ports in 'dpif' has not changed, returns EAGAIN.  May also
 257      * return other positive errno values to indicate that something has gone
 258      * wrong. */
 259     int (*port_poll)(const struct dpif *dpif, char **devnamep);
 260
 261     /* Arranges for the poll loop to wake up when 'port_poll' will return a
 262      * value other than EAGAIN. */
 263     void (*port_poll_wait)(const struct dpif *dpif);
 264
 265     /* Deletes all flows from 'dpif' and clears all of its queues of received
 266      * packets. */
 267     int (*flow_flush)(struct dpif *dpif);
 268
 269     /* Flow dumping interface.
 270      *
 271      * This is the back-end for the flow dumping interface described in
 272      * dpif.h.  Please read the comments there first, because this code
 273      * closely follows it.
 274      *
 275      * 'flow_dump_create' and 'flow_dump_thread_create' must always return an
 276      * initialized and usable data structure and defer error return until
 277      * flow_dump_destroy().  This hasn't been a problem for the dpifs that
 278      * exist so far.
 279      *
 280      * 'flow_dump_create' and 'flow_dump_thread_create' must initialize the
 281      * structures that they return with dpif_flow_dump_init() and
 282      * dpif_flow_dump_thread_init(), respectively.
 283      *
 284      * If 'terse' is true, then only UID and statistics will
 285      * be returned in the dump. Otherwise, all fields will be returned.
 286      *
 287      * If 'type' isn't null, dumps only the flows of the given type. */
 288     struct dpif_flow_dump *(*flow_dump_create)(const struct dpif *dpif,
 289                                                bool terse, char *type);
 290     int (*flow_dump_destroy)(struct dpif_flow_dump *dump);
 291
 292     struct dpif_flow_dump_thread *(*flow_dump_thread_create)(
 293         struct dpif_flow_dump *dump);
 294     void (*flow_dump_thread_destroy)(struct dpif_flow_dump_thread *thread);
 295
 296     int (*flow_dump_next)(struct dpif_flow_dump_thread *thread,
 297                           struct dpif_flow *flows, int max_flows);
 298
 299     /* Executes each of the 'n_ops' operations in 'ops' on 'dpif', in the order
 300      * in which they are specified, placing each operation's results in the
 301      * "output" members documented in comments and the 'error' member of each
 302      * dpif_op. */
 303     void (*operate)(struct dpif *dpif, struct dpif_op **ops, size_t n_ops);
 304
 305     /* Enables or disables receiving packets with dpif_recv() for 'dpif'.
 306      * Turning packet receive off and then back on is allowed to change Netlink
 307      * PID assignments (see ->port_get_pid()).  The client is responsible for
 308      * updating flows as necessary if it does this. */
 309     int (*recv_set)(struct dpif *dpif, bool enable);
 310
 311     /* Refreshes the poll loops and Netlink sockets associated to each port,
 312      * when the number of upcall handlers (upcall receiving thread) is changed
 313      * to 'n_handlers' and receiving packets for 'dpif' is enabled by
 314      * recv_set().
 315      *
 316      * Since multiple upcall handlers can read upcalls simultaneously from
 317      * 'dpif', each port can have multiple Netlink sockets, one per upcall
 318      * handler.  So, handlers_set() is responsible for the following tasks:
 319      *
 320      *    When receiving upcall is enabled, extends or creates the
 321      *    configuration to support:
 322      *
 323      *        - 'n_handlers' Netlink sockets for each port.
 324      *
 325      *        - 'n_handlers' poll loops, one for each upcall handler.
 326      *
 327      *        - registering the Netlink sockets for the same upcall handler to
 328      *          the corresponding poll loop.
 329      * */
 330     int (*handlers_set)(struct dpif *dpif, uint32_t n_handlers);
 331
 332     /* Pass custom configuration options to the datapath.  The implementation
 333      * might postpone applying the changes until run() is called. */
 334     int (*set_config)(struct dpif *dpif, const struct smap *other_config);
 335
 336     /* Translates OpenFlow queue ID 'queue_id' (in host byte order) into a
 337      * priority value used for setting packet priority. */
 338     int (*queue_to_priority)(const struct dpif *dpif, uint32_t queue_id,
 339                              uint32_t *priority);
 340
 341     /* Polls for an upcall from 'dpif' for an upcall handler.  Since there
 342      * can be multiple poll loops (see ->handlers_set()), 'handler_id' is
 343      * needed as index to identify the corresponding poll loop.  If
 344      * successful, stores the upcall into '*upcall', using 'buf' for
 345      * storage.  Should only be called if 'recv_set' has been used to enable
 346      * receiving packets from 'dpif'.
 347      *
 348      * The implementation should point 'upcall->key' and 'upcall->userdata'
 349      * (if any) into data in the caller-provided 'buf'.  The implementation may
 350      * also use 'buf' for storing the data of 'upcall->packet'.  If necessary
 351      * to make room, the implementation may reallocate the data in 'buf'.
 352      *
 353      * The caller owns the data of 'upcall->packet' and may modify it.  If
 354      * packet's headroom is exhausted as it is manipulated, 'upcall->packet'
 355      * will be reallocated.  This requires the data of 'upcall->packet' to be
 356      * released with ofpbuf_uninit() before 'upcall' is destroyed.  However,
 357      * when an error is returned, the 'upcall->packet' may be uninitialized
 358      * and should not be released.
 359      *
 360      * This function must not block.  If no upcall is pending when it is
 361      * called, it should return EAGAIN without blocking. */
 362     int (*recv)(struct dpif *dpif, uint32_t handler_id,
 363                 struct dpif_upcall *upcall, struct ofpbuf *buf);
 364
 365     /* Arranges for the poll loop for an upcall handler to wake up when 'dpif'
 366      * has a message queued to be received with the recv member functions.
 367      * Since there can be multiple poll loops (see ->handlers_set()),
 368      * 'handler_id' is needed as index to identify the corresponding poll loop.
 369      * */
 370     void (*recv_wait)(struct dpif *dpif, uint32_t handler_id);
 371
 372     /* Throws away any queued upcalls that 'dpif' currently has ready to
 373      * return. */
 374     void (*recv_purge)(struct dpif *dpif);
 375
 376     /* When 'dpif' is about to purge the datapath, the higher layer may want
 377      * to be notified so that it could try reacting accordingly (e.g. grabbing
 378      * all flow stats before they are gone).
 379      *
 380      * Registers an upcall callback function with 'dpif'.  This is only used
 381      * if 'dpif' needs to notify the purging of datapath.  'aux' is passed to
 382      * the callback on invocation. */
 383     void (*register_dp_purge_cb)(struct dpif *, dp_purge_callback *, void *aux);
 384
 385     /* For datapaths that run in userspace (i.e. dpif-netdev), threads polling
 386      * for incoming packets can directly call upcall functions instead of
 387      * offloading packet processing to separate handler threads. Datapaths
 388      * that directly call upcall functions should use the functions below to
 389      * to register an upcall function and enable / disable upcalls.
 390      *
 391      * Registers an upcall callback function with 'dpif'. This is only used
 392      * if 'dpif' directly executes upcall functions. 'aux' is passed to the
 393      * callback on invocation. */
 394     void (*register_upcall_cb)(struct dpif *, upcall_callback *, void *aux);
 395
 396     /* Enables upcalls if 'dpif' directly executes upcall functions. */
 397     void (*enable_upcall)(struct dpif *);
 398
 399     /* Disables upcalls if 'dpif' directly executes upcall functions. */
 400     void (*disable_upcall)(struct dpif *);
 401
 402     /* Get datapath version. Caller is responsible for freeing the string
 403      * returned.  */
 404     char *(*get_datapath_version)(void);
 405
 406     /* Conntrack entry dumping interface.
 407      *
 408      * These functions are used by ct-dpif.c to provide a datapath-agnostic
 409      * dumping interface to the connection trackers provided by the
 410      * datapaths.
 411      *
 412      * ct_dump_start() should put in '*state' a pointer to a newly allocated
 413      * stucture that will be passed by the caller to ct_dump_next() and
 414      * ct_dump_done(). If 'zone' is not NULL, only the entries in '*zone'
 415      * should be dumped.
 416      *
 417      * ct_dump_next() should fill 'entry' with information from a connection
 418      * and prepare to dump the next one on a subsequest invocation.
 419      *
 420      * ct_dump_done() should perform any cleanup necessary (including
 421      * deallocating the 'state' structure, if applicable). */
 422     int (*ct_dump_start)(struct dpif *, struct ct_dpif_dump_state **state,
 423                          const uint16_t *zone, int *);
 424     int (*ct_dump_next)(struct dpif *, struct ct_dpif_dump_state *state,
 425                         struct ct_dpif_entry *entry);
 426     int (*ct_dump_done)(struct dpif *, struct ct_dpif_dump_state *state);
 427
 428     /* Flushes the connection tracking tables.  The arguments have the
 429      * following behavior:
 430      *
 431      *   - If both 'zone' and 'tuple' are NULL, flush all the conntrack
 432      *     entries.
 433      *   - If 'zone' is not NULL, and 'tuple' is NULL, flush all the
 434      *     conntrack entries in '*zone'.
 435      *   - If 'tuple' is not NULL, flush the conntrack entry specified by
 436      *     'tuple' in '*zone'. If 'zone' is NULL, use the default zone
 437      *     (zone 0). */
 438     int (*ct_flush)(struct dpif *, const uint16_t *zone,
 439                     const struct ct_dpif_tuple *tuple);
 440     /* Set max connections allowed. */
 441     int (*ct_set_maxconns)(struct dpif *, uint32_t maxconns);
 442     /* Get max connections allowed. */
 443     int (*ct_get_maxconns)(struct dpif *, uint32_t *maxconns);
 444     /* Get number of connections tracked. */
 445     int (*ct_get_nconns)(struct dpif *, uint32_t *nconns);
 446
 447     /* Meters */
 448
 449     /* Queries 'dpif' for supported meter features.
 450      * NULL pointer means no meter features are supported. */
 451     void (*meter_get_features)(const struct dpif *,
 452                                struct ofputil_meter_features *);
 453
 454     /* Adds or modifies 'meter' in 'dpif'.   If '*meter_id' is UINT32_MAX,
 455      * adds a new meter, otherwise modifies an existing meter.
 456      *
 457      * If meter is successfully added, sets '*meter_id' to the new meter's
 458      * meter id selected by 'dpif'. */
 459     int (*meter_set)(struct dpif *, ofproto_meter_id *meter_id,
 460                      struct ofputil_meter_config *);
 461
 462     /* Queries 'dpif' for meter stats with the given 'meter_id'.  Stores
 463      * maximum of 'n_bands' meter statistics, returning the number of band
 464      * stats returned in 'stats->n_bands' if successful. */
 465     int (*meter_get)(const struct dpif *, ofproto_meter_id meter_id,
 466                      struct ofputil_meter_stats *, uint16_t n_bands);
 467
 468     /* Removes meter 'meter_id' from 'dpif'. Stores meter and band statistics
 469      * (for maximum of 'n_bands', returning the number of band stats returned
 470      * in 'stats->n_bands' if successful.  'stats' may be passed in as NULL if
 471      * no stats are needed, in which case 'n_bands' must be passed in as
 472      * zero. */
 473     int (*meter_del)(struct dpif *, ofproto_meter_id meter_id,
 474                      struct ofputil_meter_stats *, uint16_t n_bands);
 475 };
 476
 477 extern const struct dpif_class dpif_netlink_class;
 478 extern const struct dpif_class dpif_netdev_class;
 479
 480 #ifdef  __cplusplus
 481 }
 482 #endif
 483
 484 #endif /* dpif-provider.h */