lib/dpif-provider.h

   1 /*
   2  * Copyright (c) 2009, 2010, 2011, 2012, 2013 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 /* Datapath interface class structure, to be defined by each implementation of
  55  * a datapath interface.
  56  *
  57  * These functions return 0 if successful or a positive errno value on failure,
  58  * except where otherwise noted.
  59  *
  60  * These functions are expected to execute synchronously, that is, to block as
  61  * necessary to obtain a result.  Thus, they may not return EAGAIN or
  62  * EWOULDBLOCK or EINPROGRESS.  We may relax this requirement in the future if
  63  * and when we encounter performance problems. */
  64 struct dpif_class {
  65     /* Type of dpif in this class, e.g. "system", "netdev", etc.
  66      *
  67      * One of the providers should supply a "system" type, since this is
  68      * the type assumed if no type is specified when opening a dpif. */
  69     const char *type;
  70
  71     /* Enumerates the names of all known created datapaths, if possible, into
  72      * 'all_dps'.  The caller has already initialized 'all_dps' and other dpif
  73      * classes might already have added names to it.
  74      *
  75      * This is used by the vswitch at startup, so that it can delete any
  76      * datapaths that are not configured.
  77      *
  78      * Some kinds of datapaths might not be practically enumerable, in which
  79      * case this function may be a null pointer. */
  80     int (*enumerate)(struct sset *all_dps);
  81
  82     /* Returns the type to pass to netdev_open() when a dpif of class
  83      * 'dpif_class' has a port of type 'type', for a few special cases
  84      * when a netdev type differs from a port type.  For example, when
  85      * using the userspace datapath, a port of type "internal" needs to
  86      * be opened as "tap".
  87      *
  88      * Returns either 'type' itself or a string literal, which must not
  89      * be freed. */
  90     const char *(*port_open_type)(const struct dpif_class *dpif_class,
  91                                   const char *type);
  92
  93     /* Attempts to open an existing dpif called 'name', if 'create' is false,
  94      * or to open an existing dpif or create a new one, if 'create' is true.
  95      *
  96      * 'dpif_class' is the class of dpif to open.
  97      *
  98      * If successful, stores a pointer to the new dpif in '*dpifp', which must
  99      * have class 'dpif_class'.  On failure there are no requirements on what
 100      * is stored in '*dpifp'. */
 101     int (*open)(const struct dpif_class *dpif_class,
 102                 const char *name, bool create, struct dpif **dpifp);
 103
 104     /* Closes 'dpif' and frees associated memory. */
 105     void (*close)(struct dpif *dpif);
 106
 107     /* Attempts to destroy the dpif underlying 'dpif'.
 108      *
 109      * If successful, 'dpif' will not be used again except as an argument for
 110      * the 'close' member function. */
 111     int (*destroy)(struct dpif *dpif);
 112
 113     /* Performs periodic work needed by 'dpif', if any is necessary. */
 114     void (*run)(struct dpif *dpif);
 115
 116     /* Arranges for poll_block() to wake up if the "run" member function needs
 117      * to be called for 'dpif'. */
 118     void (*wait)(struct dpif *dpif);
 119
 120     /* Retrieves statistics for 'dpif' into 'stats'. */
 121     int (*get_stats)(const struct dpif *dpif, struct dpif_dp_stats *stats);
 122
 123     /* Adds 'netdev' as a new port in 'dpif'.  If '*port_no' is not
 124      * UINT32_MAX, attempts to use that as the port's port number.
 125      *
 126      * If port is successfully added, sets '*port_no' to the new port's
 127      * port number.  Returns EBUSY if caller attempted to choose a port
 128      * number, and it was in use. */
 129     int (*port_add)(struct dpif *dpif, struct netdev *netdev,
 130                     odp_port_t *port_no);
 131
 132     /* Removes port numbered 'port_no' from 'dpif'. */
 133     int (*port_del)(struct dpif *dpif, odp_port_t port_no);
 134
 135     /* Queries 'dpif' for a port with the given 'port_no' or 'devname'.
 136      * If 'port' is not null, stores information about the port into
 137      * '*port' if successful.
 138      *
 139      * If 'port' is not null, the caller takes ownership of data in
 140      * 'port' and must free it with dpif_port_destroy() when it is no
 141      * longer needed. */
 142     int (*port_query_by_number)(const struct dpif *dpif, odp_port_t port_no,
 143                                 struct dpif_port *port);
 144     int (*port_query_by_name)(const struct dpif *dpif, const char *devname,
 145                               struct dpif_port *port);
 146
 147     /* Returns the Netlink PID value to supply in OVS_ACTION_ATTR_USERSPACE
 148      * actions as the OVS_USERSPACE_ATTR_PID attribute's value, for use in
 149      * flows whose packets arrived on port 'port_no'.
 150      *
 151      * A 'port_no' of UINT32_MAX should be treated as a special case.  The
 152      * implementation should return a reserved PID, not allocated to any port,
 153      * that the client may use for special purposes.
 154      *
 155      * The return value only needs to be meaningful when DPIF_UC_ACTION has
 156      * been enabled in the 'dpif''s listen mask, and it is allowed to change
 157      * when DPIF_UC_ACTION is disabled and then re-enabled.
 158      *
 159      * A dpif provider that doesn't have meaningful Netlink PIDs can use NULL
 160      * for this function.  This is equivalent to always returning 0. */
 161     uint32_t (*port_get_pid)(const struct dpif *dpif, odp_port_t port_no);
 162
 163     /* Attempts to begin dumping the ports in a dpif.  On success, returns 0
 164      * and initializes '*statep' with any data needed for iteration.  On
 165      * failure, returns a positive errno value. */
 166     int (*port_dump_start)(const struct dpif *dpif, void **statep);
 167
 168     /* Attempts to retrieve another port from 'dpif' for 'state', which was
 169      * initialized by a successful call to the 'port_dump_start' function for
 170      * 'dpif'.  On success, stores a new dpif_port into 'port' and returns 0.
 171      * Returns EOF if the end of the port table has been reached, or a positive
 172      * errno value on error.  This function will not be called again once it
 173      * returns nonzero once for a given iteration (but the 'port_dump_done'
 174      * function will be called afterward).
 175      *
 176      * The dpif provider retains ownership of the data stored in 'port'.  It
 177      * must remain valid until at least the next call to 'port_dump_next' or
 178      * 'port_dump_done' for 'state'. */
 179     int (*port_dump_next)(const struct dpif *dpif, void *state,
 180                           struct dpif_port *port);
 181
 182     /* Releases resources from 'dpif' for 'state', which was initialized by a
 183      * successful call to the 'port_dump_start' function for 'dpif'.  */
 184     int (*port_dump_done)(const struct dpif *dpif, void *state);
 185
 186     /* Polls for changes in the set of ports in 'dpif'.  If the set of ports in
 187      * 'dpif' has changed, then this function should do one of the
 188      * following:
 189      *
 190      * - Preferably: store the name of the device that was added to or deleted
 191      *   from 'dpif' in '*devnamep' and return 0.  The caller is responsible
 192      *   for freeing '*devnamep' (with free()) when it no longer needs it.
 193      *
 194      * - Alternatively: return ENOBUFS, without indicating the device that was
 195      *   added or deleted.
 196      *
 197      * Occasional 'false positives', in which the function returns 0 while
 198      * indicating a device that was not actually added or deleted or returns
 199      * ENOBUFS without any change, are acceptable.
 200      *
 201      * If the set of ports in 'dpif' has not changed, returns EAGAIN.  May also
 202      * return other positive errno values to indicate that something has gone
 203      * wrong. */
 204     int (*port_poll)(const struct dpif *dpif, char **devnamep);
 205
 206     /* Arranges for the poll loop to wake up when 'port_poll' will return a
 207      * value other than EAGAIN. */
 208     void (*port_poll_wait)(const struct dpif *dpif);
 209
 210     /* Queries 'dpif' for a flow entry.  The flow is specified by the Netlink
 211      * attributes with types OVS_KEY_ATTR_* in the 'key_len' bytes starting at
 212      * 'key'.
 213      *
 214      * Returns 0 if successful.  If no flow matches, returns ENOENT.  On other
 215      * failure, returns a positive errno value.
 216      *
 217      * If 'actionsp' is nonnull, then on success '*actionsp' must be set to an
 218      * ofpbuf owned by the caller that contains the Netlink attributes for the
 219      * flow's actions.  The caller must free the ofpbuf (with ofpbuf_delete())
 220      * when it is no longer needed.
 221      *
 222      * If 'stats' is nonnull, then on success it must be updated with the
 223      * flow's statistics. */
 224     int (*flow_get)(const struct dpif *dpif,
 225                     const struct nlattr *key, size_t key_len,
 226                     struct ofpbuf **actionsp, struct dpif_flow_stats *stats);
 227
 228     /* Adds or modifies a flow in 'dpif'.  The flow is specified by the Netlink
 229      * attributes with types OVS_KEY_ATTR_* in the 'put->key_len' bytes
 230      * starting at 'put->key'.  The associated actions are specified by the
 231      * Netlink attributes with types OVS_ACTION_ATTR_* in the
 232      * 'put->actions_len' bytes starting at 'put->actions'.
 233      *
 234      * - If the flow's key does not exist in 'dpif', then the flow will be
 235      *   added if 'put->flags' includes DPIF_FP_CREATE.  Otherwise the
 236      *   operation will fail with ENOENT.
 237      *
 238      *   If the operation succeeds, then 'put->stats', if nonnull, must be
 239      *   zeroed.
 240      *
 241      * - If the flow's key does exist in 'dpif', then the flow's actions will
 242      *   be updated if 'put->flags' includes DPIF_FP_MODIFY.  Otherwise the
 243      *   operation will fail with EEXIST.  If the flow's actions are updated,
 244      *   then its statistics will be zeroed if 'put->flags' includes
 245      *   DPIF_FP_ZERO_STATS, and left as-is otherwise.
 246      *
 247      *   If the operation succeeds, then 'put->stats', if nonnull, must be set
 248      *   to the flow's statistics before the update.
 249      */
 250     int (*flow_put)(struct dpif *dpif, const struct dpif_flow_put *put);
 251
 252     /* Deletes a flow from 'dpif' and returns 0, or returns ENOENT if 'dpif'
 253      * does not contain such a flow.  The flow is specified by the Netlink
 254      * attributes with types OVS_KEY_ATTR_* in the 'del->key_len' bytes
 255      * starting at 'del->key'.
 256      *
 257      * If the operation succeeds, then 'del->stats', if nonnull, must be set to
 258      * the flow's statistics before its deletion. */
 259     int (*flow_del)(struct dpif *dpif, const struct dpif_flow_del *del);
 260
 261     /* Deletes all flows from 'dpif' and clears all of its queues of received
 262      * packets. */
 263     int (*flow_flush)(struct dpif *dpif);
 264
 265     /* Attempts to begin dumping the flows in a dpif.  On success, returns 0
 266      * and initializes '*statep' with any data needed for iteration.  On
 267      * failure, returns a positive errno value. */
 268     int (*flow_dump_start)(const struct dpif *dpif, void **statep);
 269
 270     /* Attempts to retrieve another flow from 'dpif' for 'state', which was
 271      * initialized by a successful call to the 'flow_dump_start' function for
 272      * 'dpif'.  On success, updates the output parameters as described below
 273      * and returns 0.  Returns EOF if the end of the flow table has been
 274      * reached, or a positive errno value on error.  This function will not be
 275      * called again once it returns nonzero within a given iteration (but the
 276      * 'flow_dump_done' function will be called afterward).
 277      *
 278      * On success:
 279      *
 280      *     - If 'key' and 'key_len' are nonnull, then '*key' and '*key_len'
 281      *       must be set to Netlink attributes with types OVS_KEY_ATTR_*
 282      *       representing the dumped flow's key.
 283      *
 284      *     - If 'mask' and 'mask_len' are nonnull then '*mask' and '*mask_len'
 285      *       must be set to Netlink attributes with types of OVS_KEY_ATTR_*
 286      *       representing the dumped flow's mask.
 287      *
 288      *     - If 'actions' and 'actions_len' are nonnull then they should be set
 289      *       to Netlink attributes with types OVS_ACTION_ATTR_* representing
 290      *       the dumped flow's actions.
 291      *
 292      *     - If 'stats' is nonnull then it should be set to the dumped flow's
 293      *       statistics.
 294      *
 295      * All of the returned data is owned by 'dpif', not by the caller, and the
 296      * caller must not modify or free it.  'dpif' must guarantee that it
 297      * remains accessible and unchanging until at least the next call to
 298      * 'flow_dump_next' or 'flow_dump_done' for 'state'. */
 299     int (*flow_dump_next)(const struct dpif *dpif, void *state,
 300                           const struct nlattr **key, size_t *key_len,
 301                           const struct nlattr **mask, size_t *mask_len,
 302                           const struct nlattr **actions, size_t *actions_len,
 303                           const struct dpif_flow_stats **stats);
 304
 305     /* Releases resources from 'dpif' for 'state', which was initialized by a
 306      * successful call to the 'flow_dump_start' function for 'dpif'.  */
 307     int (*flow_dump_done)(const struct dpif *dpif, void *state);
 308
 309     /* Performs the 'execute->actions_len' bytes of actions in
 310      * 'execute->actions' on the Ethernet frame in 'execute->packet'
 311      * and on the packet metadata in 'execute->md'.
 312      * May modify both packet and metadata. */
 313     int (*execute)(struct dpif *dpif, struct dpif_execute *execute);
 314
 315     /* Executes each of the 'n_ops' operations in 'ops' on 'dpif', in the order
 316      * in which they are specified, placing each operation's results in the
 317      * "output" members documented in comments.
 318      *
 319      * This function is optional.  It is only worthwhile to implement it if
 320      * 'dpif' can perform operations in batch faster than individually. */
 321     void (*operate)(struct dpif *dpif, struct dpif_op **ops, size_t n_ops);
 322
 323     /* Enables or disables receiving packets with dpif_recv() for 'dpif'.
 324      * Turning packet receive off and then back on is allowed to change Netlink
 325      * PID assignments (see ->port_get_pid()).  The client is responsible for
 326      * updating flows as necessary if it does this. */
 327     int (*recv_set)(struct dpif *dpif, bool enable);
 328
 329     /* Translates OpenFlow queue ID 'queue_id' (in host byte order) into a
 330      * priority value used for setting packet priority. */
 331     int (*queue_to_priority)(const struct dpif *dpif, uint32_t queue_id,
 332                              uint32_t *priority);
 333
 334     /* Polls for an upcall from 'dpif'.  If successful, stores the upcall into
 335      * '*upcall', using 'buf' for storage.  Should only be called if 'recv_set'
 336      * has been used to enable receiving packets from 'dpif'.
 337      *
 338      * The implementation should point 'upcall->key' and 'upcall->userdata'
 339      * (if any) into data in the caller-provided 'buf'.  The implementation may
 340      * also use 'buf' for storing the data of 'upcall->packet'.  If necessary
 341      * to make room, the implementation may reallocate the data in 'buf'.
 342      *
 343      * The caller owns the data of 'upcall->packet' and may modify it.  If
 344      * packet's headroom is exhausted as it is manipulated, 'upcall->packet'
 345      * will be reallocated.  This requires the data of 'upcall->packet' to be
 346      * released with ofpbuf_uninit() before 'upcall' is destroyed.  However,
 347      * when an error is returned, the 'upcall->packet' may be uninitialized
 348      * and should not be released.
 349      *
 350      * This function must not block.  If no upcall is pending when it is
 351      * called, it should return EAGAIN without blocking. */
 352     int (*recv)(struct dpif *dpif, struct dpif_upcall *upcall,
 353                 struct ofpbuf *buf);
 354
 355     /* Arranges for the poll loop to wake up when 'dpif' has a message queued
 356      * to be received with the recv member function. */
 357     void (*recv_wait)(struct dpif *dpif);
 358
 359     /* Throws away any queued upcalls that 'dpif' currently has ready to
 360      * return. */
 361     void (*recv_purge)(struct dpif *dpif);
 362 };
 363
 364 extern const struct dpif_class dpif_linux_class;
 365 extern const struct dpif_class dpif_netdev_class;
 366
 367 #ifdef  __cplusplus
 368 }
 369 #endif
 370
 371 #endif /* dpif-provider.h */