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 /* Datapath interface class structure, to be defined by each implementation of
  77  * a datapath interface.
  78  *
  79  * These functions return 0 if successful or a positive errno value on failure,
  80  * except where otherwise noted.
  81  *
  82  * These functions are expected to execute synchronously, that is, to block as
  83  * necessary to obtain a result.  Thus, they may not return EAGAIN or
  84  * EWOULDBLOCK or EINPROGRESS.  We may relax this requirement in the future if
  85  * and when we encounter performance problems. */
  86 struct dpif_class {
  87     /* Type of dpif in this class, e.g. "system", "netdev", etc.
  88      *
  89      * One of the providers should supply a "system" type, since this is
  90      * the type assumed if no type is specified when opening a dpif. */
  91     const char *type;
  92
  93     /* Called when the dpif provider is registered, typically at program
  94      * startup.  Returning an error from this function will prevent any
  95      * datapath with this class from being created.
  96      *
  97      * This function may be set to null if a datapath class needs no
  98      * initialization at registration time. */
  99     int (*init)(void);
 100
 101     /* Enumerates the names of all known created datapaths (of class
 102      * 'dpif_class'), if possible, into 'all_dps'.  The caller has already
 103      * initialized 'all_dps' and other dpif classes might already have added
 104      * names to it.
 105      *
 106      * This is used by the vswitch at startup, so that it can delete any
 107      * datapaths that are not configured.
 108      *
 109      * Some kinds of datapaths might not be practically enumerable, in which
 110      * case this function may be a null pointer. */
 111     int (*enumerate)(struct sset *all_dps, const struct dpif_class *dpif_class);
 112
 113     /* Returns the type to pass to netdev_open() when a dpif of class
 114      * 'dpif_class' has a port of type 'type', for a few special cases
 115      * when a netdev type differs from a port type.  For example, when
 116      * using the userspace datapath, a port of type "internal" needs to
 117      * be opened as "tap".
 118      *
 119      * Returns either 'type' itself or a string literal, which must not
 120      * be freed. */
 121     const char *(*port_open_type)(const struct dpif_class *dpif_class,
 122                                   const char *type);
 123
 124     /* Attempts to open an existing dpif called 'name', if 'create' is false,
 125      * or to open an existing dpif or create a new one, if 'create' is true.
 126      *
 127      * 'dpif_class' is the class of dpif to open.
 128      *
 129      * If successful, stores a pointer to the new dpif in '*dpifp', which must
 130      * have class 'dpif_class'.  On failure there are no requirements on what
 131      * is stored in '*dpifp'. */
 132     int (*open)(const struct dpif_class *dpif_class,
 133                 const char *name, bool create, struct dpif **dpifp);
 134
 135     /* Closes 'dpif' and frees associated memory. */
 136     void (*close)(struct dpif *dpif);
 137
 138     /* Attempts to destroy the dpif underlying 'dpif'.
 139      *
 140      * If successful, 'dpif' will not be used again except as an argument for
 141      * the 'close' member function. */
 142     int (*destroy)(struct dpif *dpif);
 143
 144     /* Performs periodic work needed by 'dpif', if any is necessary.
 145      * Returns true if need to revalidate. */
 146     bool (*run)(struct dpif *dpif);
 147
 148     /* Arranges for poll_block() to wake up if the "run" member function needs
 149      * to be called for 'dpif'. */
 150     void (*wait)(struct dpif *dpif);
 151
 152     /* Retrieves statistics for 'dpif' into 'stats'. */
 153     int (*get_stats)(const struct dpif *dpif, struct dpif_dp_stats *stats);
 154
 155     /* Adds 'netdev' as a new port in 'dpif'.  If '*port_no' is not
 156      * UINT32_MAX, attempts to use that as the port's port number.
 157      *
 158      * If port is successfully added, sets '*port_no' to the new port's
 159      * port number.  Returns EBUSY if caller attempted to choose a port
 160      * number, and it was in use. */
 161     int (*port_add)(struct dpif *dpif, struct netdev *netdev,
 162                     odp_port_t *port_no);
 163
 164     /* Removes port numbered 'port_no' from 'dpif'. */
 165     int (*port_del)(struct dpif *dpif, odp_port_t port_no);
 166
 167     /* Queries 'dpif' for a port with the given 'port_no' or 'devname'.
 168      * If 'port' is not null, stores information about the port into
 169      * '*port' if successful.
 170      *
 171      * If 'port' is not null, the caller takes ownership of data in
 172      * 'port' and must free it with dpif_port_destroy() when it is no
 173      * longer needed. */
 174     int (*port_query_by_number)(const struct dpif *dpif, odp_port_t port_no,
 175                                 struct dpif_port *port);
 176     int (*port_query_by_name)(const struct dpif *dpif, const char *devname,
 177                               struct dpif_port *port);
 178
 179     /* Returns the Netlink PID value to supply in OVS_ACTION_ATTR_USERSPACE
 180      * actions as the OVS_USERSPACE_ATTR_PID attribute's value, for use in
 181      * flows whose packets arrived on port 'port_no'.  In the case where the
 182      * provider allocates multiple Netlink PIDs to a single port, it may use
 183      * 'hash' to spread load among them.  The caller need not use a particular
 184      * hash function; a 5-tuple hash is suitable.
 185      *
 186      * (The datapath implementation might use some different hash function for
 187      * distributing packets received via flow misses among PIDs.  This means
 188      * that packets received via flow misses might be reordered relative to
 189      * packets received via userspace actions.  This is not ordinarily a
 190      * problem.)
 191      *
 192      * A 'port_no' of UINT32_MAX should be treated as a special case.  The
 193      * implementation should return a reserved PID, not allocated to any port,
 194      * that the client may use for special purposes.
 195      *
 196      * The return value only needs to be meaningful when DPIF_UC_ACTION has
 197      * been enabled in the 'dpif''s listen mask, and it is allowed to change
 198      * when DPIF_UC_ACTION is disabled and then re-enabled.
 199      *
 200      * A dpif provider that doesn't have meaningful Netlink PIDs can use NULL
 201      * for this function.  This is equivalent to always returning 0. */
 202     uint32_t (*port_get_pid)(const struct dpif *dpif, odp_port_t port_no,
 203                              uint32_t hash);
 204
 205     /* Attempts to begin dumping the ports in a dpif.  On success, returns 0
 206      * and initializes '*statep' with any data needed for iteration.  On
 207      * failure, returns a positive errno value. */
 208     int (*port_dump_start)(const struct dpif *dpif, void **statep);
 209
 210     /* Attempts to retrieve another port from 'dpif' for 'state', which was
 211      * initialized by a successful call to the 'port_dump_start' function for
 212      * 'dpif'.  On success, stores a new dpif_port into 'port' and returns 0.
 213      * Returns EOF if the end of the port table has been reached, or a positive
 214      * errno value on error.  This function will not be called again once it
 215      * returns nonzero once for a given iteration (but the 'port_dump_done'
 216      * function will be called afterward).
 217      *
 218      * The dpif provider retains ownership of the data stored in 'port'.  It
 219      * must remain valid until at least the next call to 'port_dump_next' or
 220      * 'port_dump_done' for 'state'. */
 221     int (*port_dump_next)(const struct dpif *dpif, void *state,
 222                           struct dpif_port *port);
 223
 224     /* Releases resources from 'dpif' for 'state', which was initialized by a
 225      * successful call to the 'port_dump_start' function for 'dpif'.  */
 226     int (*port_dump_done)(const struct dpif *dpif, void *state);
 227
 228     /* Polls for changes in the set of ports in 'dpif'.  If the set of ports in
 229      * 'dpif' has changed, then this function should do one of the
 230      * following:
 231      *
 232      * - Preferably: store the name of the device that was added to or deleted
 233      *   from 'dpif' in '*devnamep' and return 0.  The caller is responsible
 234      *   for freeing '*devnamep' (with free()) when it no longer needs it.
 235      *
 236      * - Alternatively: return ENOBUFS, without indicating the device that was
 237      *   added or deleted.
 238      *
 239      * Occasional 'false positives', in which the function returns 0 while
 240      * indicating a device that was not actually added or deleted or returns
 241      * ENOBUFS without any change, are acceptable.
 242      *
 243      * If the set of ports in 'dpif' has not changed, returns EAGAIN.  May also
 244      * return other positive errno values to indicate that something has gone
 245      * wrong. */
 246     int (*port_poll)(const struct dpif *dpif, char **devnamep);
 247
 248     /* Arranges for the poll loop to wake up when 'port_poll' will return a
 249      * value other than EAGAIN. */
 250     void (*port_poll_wait)(const struct dpif *dpif);
 251
 252     /* Deletes all flows from 'dpif' and clears all of its queues of received
 253      * packets. */
 254     int (*flow_flush)(struct dpif *dpif);
 255
 256     /* Flow dumping interface.
 257      *
 258      * This is the back-end for the flow dumping interface described in
 259      * dpif.h.  Please read the comments there first, because this code
 260      * closely follows it.
 261      *
 262      * 'flow_dump_create' and 'flow_dump_thread_create' must always return an
 263      * initialized and usable data structure and defer error return until
 264      * flow_dump_destroy().  This hasn't been a problem for the dpifs that
 265      * exist so far.
 266      *
 267      * 'flow_dump_create' and 'flow_dump_thread_create' must initialize the
 268      * structures that they return with dpif_flow_dump_init() and
 269      * dpif_flow_dump_thread_init(), respectively.
 270      *
 271      * If 'terse' is true, then only UID and statistics will
 272      * be returned in the dump. Otherwise, all fields will be returned. */
 273     struct dpif_flow_dump *(*flow_dump_create)(const struct dpif *dpif,
 274                                                bool terse);
 275     int (*flow_dump_destroy)(struct dpif_flow_dump *dump);
 276
 277     struct dpif_flow_dump_thread *(*flow_dump_thread_create)(
 278         struct dpif_flow_dump *dump);
 279     void (*flow_dump_thread_destroy)(struct dpif_flow_dump_thread *thread);
 280
 281     int (*flow_dump_next)(struct dpif_flow_dump_thread *thread,
 282                           struct dpif_flow *flows, int max_flows);
 283
 284     /* Executes each of the 'n_ops' operations in 'ops' on 'dpif', in the order
 285      * in which they are specified, placing each operation's results in the
 286      * "output" members documented in comments and the 'error' member of each
 287      * dpif_op. */
 288     void (*operate)(struct dpif *dpif, struct dpif_op **ops, size_t n_ops);
 289
 290     /* Enables or disables receiving packets with dpif_recv() for 'dpif'.
 291      * Turning packet receive off and then back on is allowed to change Netlink
 292      * PID assignments (see ->port_get_pid()).  The client is responsible for
 293      * updating flows as necessary if it does this. */
 294     int (*recv_set)(struct dpif *dpif, bool enable);
 295
 296     /* Refreshes the poll loops and Netlink sockets associated to each port,
 297      * when the number of upcall handlers (upcall receiving thread) is changed
 298      * to 'n_handlers' and receiving packets for 'dpif' is enabled by
 299      * recv_set().
 300      *
 301      * Since multiple upcall handlers can read upcalls simultaneously from
 302      * 'dpif', each port can have multiple Netlink sockets, one per upcall
 303      * handler.  So, handlers_set() is responsible for the following tasks:
 304      *
 305      *    When receiving upcall is enabled, extends or creates the
 306      *    configuration to support:
 307      *
 308      *        - 'n_handlers' Netlink sockets for each port.
 309      *
 310      *        - 'n_handlers' poll loops, one for each upcall handler.
 311      *
 312      *        - registering the Netlink sockets for the same upcall handler to
 313      *          the corresponding poll loop.
 314      * */
 315     int (*handlers_set)(struct dpif *dpif, uint32_t n_handlers);
 316
 317     /* If 'dpif' creates its own I/O polling threads, refreshes poll threads
 318      * configuration.  'n_rxqs' configures the number of rx_queues, which
 319      * are distributed among threads.  'cmask' configures the cpu mask
 320      * for setting the polling threads' cpu affinity. */
 321     int (*poll_threads_set)(struct dpif *dpif, unsigned int n_rxqs,
 322                             const char *cmask);
 323
 324     /* Translates OpenFlow queue ID 'queue_id' (in host byte order) into a
 325      * priority value used for setting packet priority. */
 326     int (*queue_to_priority)(const struct dpif *dpif, uint32_t queue_id,
 327                              uint32_t *priority);
 328
 329     /* Polls for an upcall from 'dpif' for an upcall handler.  Since there
 330      * can be multiple poll loops (see ->handlers_set()), 'handler_id' is
 331      * needed as index to identify the corresponding poll loop.  If
 332      * successful, stores the upcall into '*upcall', using 'buf' for
 333      * storage.  Should only be called if 'recv_set' has been used to enable
 334      * receiving packets from 'dpif'.
 335      *
 336      * The implementation should point 'upcall->key' and 'upcall->userdata'
 337      * (if any) into data in the caller-provided 'buf'.  The implementation may
 338      * also use 'buf' for storing the data of 'upcall->packet'.  If necessary
 339      * to make room, the implementation may reallocate the data in 'buf'.
 340      *
 341      * The caller owns the data of 'upcall->packet' and may modify it.  If
 342      * packet's headroom is exhausted as it is manipulated, 'upcall->packet'
 343      * will be reallocated.  This requires the data of 'upcall->packet' to be
 344      * released with ofpbuf_uninit() before 'upcall' is destroyed.  However,
 345      * when an error is returned, the 'upcall->packet' may be uninitialized
 346      * and should not be released.
 347      *
 348      * This function must not block.  If no upcall is pending when it is
 349      * called, it should return EAGAIN without blocking. */
 350     int (*recv)(struct dpif *dpif, uint32_t handler_id,
 351                 struct dpif_upcall *upcall, struct ofpbuf *buf);
 352
 353     /* Arranges for the poll loop for an upcall handler to wake up when 'dpif'
 354      * has a message queued to be received with the recv member functions.
 355      * Since there can be multiple poll loops (see ->handlers_set()),
 356      * 'handler_id' is needed as index to identify the corresponding poll loop.
 357      * */
 358     void (*recv_wait)(struct dpif *dpif, uint32_t handler_id);
 359
 360     /* Throws away any queued upcalls that 'dpif' currently has ready to
 361      * return. */
 362     void (*recv_purge)(struct dpif *dpif);
 363
 364     /* When 'dpif' is about to purge the datapath, the higher layer may want
 365      * to be notified so that it could try reacting accordingly (e.g. grabbing
 366      * all flow stats before they are gone).
 367      *
 368      * Registers an upcall callback function with 'dpif'.  This is only used
 369      * if 'dpif' needs to notify the purging of datapath.  'aux' is passed to
 370      * the callback on invocation. */
 371     void (*register_dp_purge_cb)(struct dpif *, dp_purge_callback *, void *aux);
 372
 373     /* For datapaths that run in userspace (i.e. dpif-netdev), threads polling
 374      * for incoming packets can directly call upcall functions instead of
 375      * offloading packet processing to separate handler threads. Datapaths
 376      * that directly call upcall functions should use the functions below to
 377      * to register an upcall function and enable / disable upcalls.
 378      *
 379      * Registers an upcall callback function with 'dpif'. This is only used
 380      * if 'dpif' directly executes upcall functions. 'aux' is passed to the
 381      * callback on invocation. */
 382     void (*register_upcall_cb)(struct dpif *, upcall_callback *, void *aux);
 383
 384     /* Enables upcalls if 'dpif' directly executes upcall functions. */
 385     void (*enable_upcall)(struct dpif *);
 386
 387     /* Disables upcalls if 'dpif' directly executes upcall functions. */
 388     void (*disable_upcall)(struct dpif *);
 389
 390     /* Get datapath version. Caller is responsible for freeing the string
 391      * returned.  */
 392     char *(*get_datapath_version)(void);
 393 };
 394
 395 extern const struct dpif_class dpif_netlink_class;
 396 extern const struct dpif_class dpif_netdev_class;
 397
 398 #ifdef  __cplusplus
 399 }
 400 #endif
 401
 402 #endif /* dpif-provider.h */