lib/dpif-provider.h

   1 /*
   2  * Copyright (c) 2009, 2010, 2011, 2012 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 <assert.h>
  26 #include "openflow/openflow.h"
  27 #include "dpif.h"
  28 #include "util.h"
  29
  30 #ifdef  __cplusplus
  31 extern "C" {
  32 #endif
  33
  34 /* Open vSwitch datapath interface.
  35  *
  36  * This structure should be treated as opaque by dpif implementations. */
  37 struct dpif {
  38     const struct dpif_class *dpif_class;
  39     char *base_name;
  40     char *full_name;
  41     uint8_t netflow_engine_type;
  42     uint8_t netflow_engine_id;
  43 };
  44
  45 void dpif_init(struct dpif *, const struct dpif_class *, const char *name,
  46                uint8_t netflow_engine_type, uint8_t netflow_engine_id);
  47 void dpif_uninit(struct dpif *dpif, bool close);
  48
  49 static inline void dpif_assert_class(const struct dpif *dpif,
  50                                      const struct dpif_class *dpif_class)
  51 {
  52     assert(dpif->dpif_class == dpif_class);
  53 }
  54
  55 /* Datapath interface class structure, to be defined by each implementation of
  56  * a datapath interface.
  57  *
  58  * These functions return 0 if successful or a positive errno value on failure,
  59  * except where otherwise noted.
  60  *
  61  * These functions are expected to execute synchronously, that is, to block as
  62  * necessary to obtain a result.  Thus, they may not return EAGAIN or
  63  * EWOULDBLOCK or EINPROGRESS.  We may relax this requirement in the future if
  64  * and when we encounter performance problems. */
  65 struct dpif_class {
  66     /* Type of dpif in this class, e.g. "system", "netdev", etc.
  67      *
  68      * One of the providers should supply a "system" type, since this is
  69      * the type assumed if no type is specified when opening a dpif. */
  70     const char *type;
  71
  72     /* Enumerates the names of all known created datapaths, if possible, into
  73      * 'all_dps'.  The caller has already initialized 'all_dps' and other dpif
  74      * classes might already have added names to it.
  75      *
  76      * This is used by the vswitch at startup, so that it can delete any
  77      * datapaths that are not configured.
  78      *
  79      * Some kinds of datapaths might not be practically enumerable, in which
  80      * case this function may be a null pointer. */
  81     int (*enumerate)(struct sset *all_dps);
  82
  83     /* Attempts to open an existing dpif called 'name', if 'create' is false,
  84      * or to open an existing dpif or create a new one, if 'create' is true.
  85      *
  86      * 'dpif_class' is the class of dpif to open.
  87      *
  88      * If successful, stores a pointer to the new dpif in '*dpifp', which must
  89      * have class 'dpif_class'.  On failure there are no requirements on what
  90      * is stored in '*dpifp'. */
  91     int (*open)(const struct dpif_class *dpif_class,
  92                 const char *name, bool create, struct dpif **dpifp);
  93
  94     /* Closes 'dpif' and frees associated memory. */
  95     void (*close)(struct dpif *dpif);
  96
  97     /* Attempts to destroy the dpif underlying 'dpif'.
  98      *
  99      * If successful, 'dpif' will not be used again except as an argument for
 100      * the 'close' member function. */
 101     int (*destroy)(struct dpif *dpif);
 102
 103     /* Performs periodic work needed by 'dpif', if any is necessary. */
 104     void (*run)(struct dpif *dpif);
 105
 106     /* Arranges for poll_block() to wake up if the "run" member function needs
 107      * to be called for 'dpif'. */
 108     void (*wait)(struct dpif *dpif);
 109
 110     /* Retrieves statistics for 'dpif' into 'stats'. */
 111     int (*get_stats)(const struct dpif *dpif, struct dpif_dp_stats *stats);
 112
 113     /* Adds 'netdev' as a new port in 'dpif'.  If '*port_no' is not
 114      * UINT16_MAX, attempts to use that as the port's port number.
 115      *
 116      * If port is successfully added, sets '*port_no' to the new port's
 117      * port number.  Returns EBUSY if caller attempted to choose a port
 118      * number, and it was in use. */
 119     int (*port_add)(struct dpif *dpif, struct netdev *netdev,
 120                     uint16_t *port_no);
 121
 122     /* Removes port numbered 'port_no' from 'dpif'. */
 123     int (*port_del)(struct dpif *dpif, uint16_t port_no);
 124
 125     /* Queries 'dpif' for a port with the given 'port_no' or 'devname'.  Stores
 126      * information about the port into '*port' if successful.
 127      *
 128      * The caller takes ownership of data in 'port' and must free it with
 129      * dpif_port_destroy() when it is no longer needed. */
 130     int (*port_query_by_number)(const struct dpif *dpif, uint16_t port_no,
 131                                 struct dpif_port *port);
 132     int (*port_query_by_name)(const struct dpif *dpif, const char *devname,
 133                               struct dpif_port *port);
 134
 135     /* Returns one greater than the largest port number accepted in flow
 136      * actions. */
 137     int (*get_max_ports)(const struct dpif *dpif);
 138
 139     /* Returns the Netlink PID value to supply in OVS_ACTION_ATTR_USERSPACE
 140      * actions as the OVS_USERSPACE_ATTR_PID attribute's value, for use in
 141      * flows whose packets arrived on port 'port_no'.
 142      *
 143      * A 'port_no' of UINT16_MAX should be treated as a special case.  The
 144      * implementation should return a reserved PID, not allocated to any port,
 145      * that the client may use for special purposes.
 146      *
 147      * The return value only needs to be meaningful when DPIF_UC_ACTION has
 148      * been enabled in the 'dpif''s listen mask, and it is allowed to change
 149      * when DPIF_UC_ACTION is disabled and then re-enabled.
 150      *
 151      * A dpif provider that doesn't have meaningful Netlink PIDs can use NULL
 152      * for this function.  This is equivalent to always returning 0. */
 153     uint32_t (*port_get_pid)(const struct dpif *dpif, uint16_t port_no);
 154
 155     /* Attempts to begin dumping the ports in a dpif.  On success, returns 0
 156      * and initializes '*statep' with any data needed for iteration.  On
 157      * failure, returns a positive errno value. */
 158     int (*port_dump_start)(const struct dpif *dpif, void **statep);
 159
 160     /* Attempts to retrieve another port from 'dpif' for 'state', which was
 161      * initialized by a successful call to the 'port_dump_start' function for
 162      * 'dpif'.  On success, stores a new dpif_port into 'port' and returns 0.
 163      * Returns EOF if the end of the port table has been reached, or a positive
 164      * errno value on error.  This function will not be called again once it
 165      * returns nonzero once for a given iteration (but the 'port_dump_done'
 166      * function will be called afterward).
 167      *
 168      * The dpif provider retains ownership of the data stored in 'port'.  It
 169      * must remain valid until at least the next call to 'port_dump_next' or
 170      * 'port_dump_done' for 'state'. */
 171     int (*port_dump_next)(const struct dpif *dpif, void *state,
 172                           struct dpif_port *port);
 173
 174     /* Releases resources from 'dpif' for 'state', which was initialized by a
 175      * successful call to the 'port_dump_start' function for 'dpif'.  */
 176     int (*port_dump_done)(const struct dpif *dpif, void *state);
 177
 178     /* Polls for changes in the set of ports in 'dpif'.  If the set of ports in
 179      * 'dpif' has changed, then this function should do one of the
 180      * following:
 181      *
 182      * - Preferably: store the name of the device that was added to or deleted
 183      *   from 'dpif' in '*devnamep' and return 0.  The caller is responsible
 184      *   for freeing '*devnamep' (with free()) when it no longer needs it.
 185      *
 186      * - Alternatively: return ENOBUFS, without indicating the device that was
 187      *   added or deleted.
 188      *
 189      * Occasional 'false positives', in which the function returns 0 while
 190      * indicating a device that was not actually added or deleted or returns
 191      * ENOBUFS without any change, are acceptable.
 192      *
 193      * If the set of ports in 'dpif' has not changed, returns EAGAIN.  May also
 194      * return other positive errno values to indicate that something has gone
 195      * wrong. */
 196     int (*port_poll)(const struct dpif *dpif, char **devnamep);
 197
 198     /* Arranges for the poll loop to wake up when 'port_poll' will return a
 199      * value other than EAGAIN. */
 200     void (*port_poll_wait)(const struct dpif *dpif);
 201
 202     /* Queries 'dpif' for a flow entry.  The flow is specified by the Netlink
 203      * attributes with types OVS_KEY_ATTR_* in the 'key_len' bytes starting at
 204      * 'key'.
 205      *
 206      * Returns 0 if successful.  If no flow matches, returns ENOENT.  On other
 207      * failure, returns a positive errno value.
 208      *
 209      * If 'actionsp' is nonnull, then on success '*actionsp' must be set to an
 210      * ofpbuf owned by the caller that contains the Netlink attributes for the
 211      * flow's actions.  The caller must free the ofpbuf (with ofpbuf_delete())
 212      * when it is no longer needed.
 213      *
 214      * If 'stats' is nonnull, then on success it must be updated with the
 215      * flow's statistics. */
 216     int (*flow_get)(const struct dpif *dpif,
 217                     const struct nlattr *key, size_t key_len,
 218                     struct ofpbuf **actionsp, struct dpif_flow_stats *stats);
 219
 220     /* Adds or modifies a flow in 'dpif'.  The flow is specified by the Netlink
 221      * attributes with types OVS_KEY_ATTR_* in the 'put->key_len' bytes
 222      * starting at 'put->key'.  The associated actions are specified by the
 223      * Netlink attributes with types OVS_ACTION_ATTR_* in the
 224      * 'put->actions_len' bytes starting at 'put->actions'.
 225      *
 226      * - If the flow's key does not exist in 'dpif', then the flow will be
 227      *   added if 'put->flags' includes DPIF_FP_CREATE.  Otherwise the
 228      *   operation will fail with ENOENT.
 229      *
 230      *   If the operation succeeds, then 'put->stats', if nonnull, must be
 231      *   zeroed.
 232      *
 233      * - If the flow's key does exist in 'dpif', then the flow's actions will
 234      *   be updated if 'put->flags' includes DPIF_FP_MODIFY.  Otherwise the
 235      *   operation will fail with EEXIST.  If the flow's actions are updated,
 236      *   then its statistics will be zeroed if 'put->flags' includes
 237      *   DPIF_FP_ZERO_STATS, and left as-is otherwise.
 238      *
 239      *   If the operation succeeds, then 'put->stats', if nonnull, must be set
 240      *   to the flow's statistics before the update.
 241      */
 242     int (*flow_put)(struct dpif *dpif, const struct dpif_flow_put *put);
 243
 244     /* Deletes a flow from 'dpif' and returns 0, or returns ENOENT if 'dpif'
 245      * does not contain such a flow.  The flow is specified by the Netlink
 246      * attributes with types OVS_KEY_ATTR_* in the 'del->key_len' bytes
 247      * starting at 'del->key'.
 248      *
 249      * If the operation succeeds, then 'del->stats', if nonnull, must be set to
 250      * the flow's statistics before its deletion. */
 251     int (*flow_del)(struct dpif *dpif, const struct dpif_flow_del *del);
 252
 253     /* Deletes all flows from 'dpif' and clears all of its queues of received
 254      * packets. */
 255     int (*flow_flush)(struct dpif *dpif);
 256
 257     /* Attempts to begin dumping the flows in a dpif.  On success, returns 0
 258      * and initializes '*statep' with any data needed for iteration.  On
 259      * failure, returns a positive errno value. */
 260     int (*flow_dump_start)(const struct dpif *dpif, void **statep);
 261
 262     /* Attempts to retrieve another flow from 'dpif' for 'state', which was
 263      * initialized by a successful call to the 'flow_dump_start' function for
 264      * 'dpif'.  On success, updates the output parameters as described below
 265      * and returns 0.  Returns EOF if the end of the flow table has been
 266      * reached, or a positive errno value on error.  This function will not be
 267      * called again once it returns nonzero within a given iteration (but the
 268      * 'flow_dump_done' function will be called afterward).
 269      *
 270      * On success, if 'key' and 'key_len' are nonnull then '*key' and
 271      * '*key_len' must be set to Netlink attributes with types OVS_KEY_ATTR_*
 272      * representing the dumped flow's key.  If 'actions' and 'actions_len' are
 273      * nonnull then they should be set to Netlink attributes with types
 274      * OVS_ACTION_ATTR_* representing the dumped flow's actions.  If 'stats'
 275      * is nonnull then it should be set to the dumped flow's statistics.
 276      *
 277      * All of the returned data is owned by 'dpif', not by the caller, and the
 278      * caller must not modify or free it.  'dpif' must guarantee that it
 279      * remains accessible and unchanging until at least the next call to
 280      * 'flow_dump_next' or 'flow_dump_done' for 'state'. */
 281     int (*flow_dump_next)(const struct dpif *dpif, void *state,
 282                           const struct nlattr **key, size_t *key_len,
 283                           const struct nlattr **actions, size_t *actions_len,
 284                           const struct dpif_flow_stats **stats);
 285
 286     /* Releases resources from 'dpif' for 'state', which was initialized by a
 287      * successful call to the 'flow_dump_start' function for 'dpif'.  */
 288     int (*flow_dump_done)(const struct dpif *dpif, void *state);
 289
 290     /* Performs the 'execute->actions_len' bytes of actions in
 291      * 'execute->actions' on the Ethernet frame specified in 'execute->packet'
 292      * taken from the flow specified in the 'execute->key_len' bytes of
 293      * 'execute->key'.  ('execute->key' is mostly redundant with
 294      * 'execute->packet', but it contains some metadata that cannot be
 295      * recovered from 'execute->packet', such as tunnel and in_port.) */
 296     int (*execute)(struct dpif *dpif, const struct dpif_execute *execute);
 297
 298     /* Executes each of the 'n_ops' operations in 'ops' on 'dpif', in the order
 299      * in which they are specified, placing each operation's results in the
 300      * "output" members documented in comments.
 301      *
 302      * This function is optional.  It is only worthwhile to implement it if
 303      * 'dpif' can perform operations in batch faster than individually. */
 304     void (*operate)(struct dpif *dpif, struct dpif_op **ops, size_t n_ops);
 305
 306     /* Enables or disables receiving packets with dpif_recv() for 'dpif'.
 307      * Turning packet receive off and then back on is allowed to change Netlink
 308      * PID assignments (see ->port_get_pid()).  The client is responsible for
 309      * updating flows as necessary if it does this. */
 310     int (*recv_set)(struct dpif *dpif, bool enable);
 311
 312     /* Translates OpenFlow queue ID 'queue_id' (in host byte order) into a
 313      * priority value used for setting packet priority. */
 314     int (*queue_to_priority)(const struct dpif *dpif, uint32_t queue_id,
 315                              uint32_t *priority);
 316
 317     /* Polls for an upcall from 'dpif'.  If successful, stores the upcall into
 318      * '*upcall', using 'buf' for storage.  Should only be called if 'recv_set'
 319      * has been used to enable receiving packets from 'dpif'.
 320      *
 321      * The implementation should point 'upcall->packet' and 'upcall->key' into
 322      * data in the caller-provided 'buf'.  If necessary to make room, the
 323      * implementation may expand the data in 'buf'.  (This is hardly a great
 324      * way to do things but it works out OK for the dpif providers that exist
 325      * so far.)
 326      *
 327      * This function must not block.  If no upcall is pending when it is
 328      * called, it should return EAGAIN without blocking. */
 329     int (*recv)(struct dpif *dpif, struct dpif_upcall *upcall,
 330                 struct ofpbuf *buf);
 331
 332     /* Arranges for the poll loop to wake up when 'dpif' has a message queued
 333      * to be received with the recv member function. */
 334     void (*recv_wait)(struct dpif *dpif);
 335
 336     /* Throws away any queued upcalls that 'dpif' currently has ready to
 337      * return. */
 338     void (*recv_purge)(struct dpif *dpif);
 339 };
 340
 341 extern const struct dpif_class dpif_linux_class;
 342 extern const struct dpif_class dpif_netdev_class;
 343
 344 #ifdef  __cplusplus
 345 }
 346 #endif
 347
 348 #endif /* dpif-provider.h */