lib/dpif-provider.h

   1 /*
   2  * Copyright (c) 2009, 2010, 2011 Nicira Networks.
   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     /* Performs periodic work needed by dpifs of this class, if any is
  73      * necessary. */
  74     void (*run)(void);
  75
  76     /* Arranges for poll_block() to wake up if the "run" member function needs
  77      * to be called. */
  78     void (*wait)(void);
  79
  80     /* Enumerates the names of all known created datapaths, if possible, into
  81      * 'all_dps'.  The caller has already initialized 'all_dps' and other dpif
  82      * classes might already have added names to it.
  83      *
  84      * This is used by the vswitch at startup, so that it can delete any
  85      * datapaths that are not configured.
  86      *
  87      * Some kinds of datapaths might not be practically enumerable, in which
  88      * case this function may be a null pointer. */
  89     int (*enumerate)(struct svec *all_dps);
  90
  91     /* Attempts to open an existing dpif called 'name', if 'create' is false,
  92      * or to open an existing dpif or create a new one, if 'create' is true.
  93      *
  94      * 'dpif_class' is the class of dpif to open.
  95      *
  96      * If successful, stores a pointer to the new dpif in '*dpifp', which must
  97      * have class 'dpif_class'.  On failure there are no requirements on what
  98      * is stored in '*dpifp'. */
  99     int (*open)(const struct dpif_class *dpif_class,
 100                 const char *name, bool create, struct dpif **dpifp);
 101
 102     /* Closes 'dpif' and frees associated memory. */
 103     void (*close)(struct dpif *dpif);
 104
 105     /* Attempts to destroy the dpif underlying 'dpif'.
 106      *
 107      * If successful, 'dpif' will not be used again except as an argument for
 108      * the 'close' member function. */
 109     int (*destroy)(struct dpif *dpif);
 110
 111     /* Retrieves statistics for 'dpif' into 'stats'. */
 112     int (*get_stats)(const struct dpif *dpif, struct odp_stats *stats);
 113
 114     /* Retrieves 'dpif''s current treatment of IP fragments into '*drop_frags':
 115      * true indicates that fragments are dropped, false indicates that
 116      * fragments are treated in the same way as other IP packets (except that
 117      * the L4 header cannot be read). */
 118     int (*get_drop_frags)(const struct dpif *dpif, bool *drop_frags);
 119
 120     /* Changes 'dpif''s treatment of IP fragments to 'drop_frags', whose
 121      * meaning is the same as for the get_drop_frags member function. */
 122     int (*set_drop_frags)(struct dpif *dpif, bool drop_frags);
 123
 124     /* Adds 'netdev' as a new port in 'dpif'.  If successful, sets '*port_no'
 125      * to the new port's port number. */
 126     int (*port_add)(struct dpif *dpif, struct netdev *netdev,
 127                     uint16_t *port_no);
 128
 129     /* Removes port numbered 'port_no' from 'dpif'. */
 130     int (*port_del)(struct dpif *dpif, uint16_t port_no);
 131
 132     /* Queries 'dpif' for a port with the given 'port_no' or 'devname'.  Stores
 133      * information about the port into '*port' if successful.
 134      *
 135      * The caller takes ownership of data in 'port' and must free it with
 136      * dpif_port_destroy() when it is no longer needed. */
 137     int (*port_query_by_number)(const struct dpif *dpif, uint16_t port_no,
 138                                 struct dpif_port *port);
 139     int (*port_query_by_name)(const struct dpif *dpif, const char *devname,
 140                               struct dpif_port *port);
 141
 142     /* Returns one greater than the largest port number accepted in flow
 143      * actions. */
 144     int (*get_max_ports)(const struct dpif *dpif);
 145
 146     /* Attempts to begin dumping the ports in a dpif.  On success, returns 0
 147      * and initializes '*statep' with any data needed for iteration.  On
 148      * failure, returns a positive errno value. */
 149     int (*port_dump_start)(const struct dpif *dpif, void **statep);
 150
 151     /* Attempts to retrieve another port from 'dpif' for 'state', which was
 152      * initialized by a successful call to the 'port_dump_start' function for
 153      * 'dpif'.  On success, stores a new dpif_port into 'port' and returns 0.
 154      * Returns EOF if the end of the port table has been reached, or a positive
 155      * errno value on error.  This function will not be called again once it
 156      * returns nonzero once for a given iteration (but the 'port_dump_done'
 157      * function will be called afterward).
 158      *
 159      * The dpif provider retains ownership of the data stored in 'port'.  It
 160      * must remain valid until at least the next call to 'port_dump_next' or
 161      * 'port_dump_done' for 'state'. */
 162     int (*port_dump_next)(const struct dpif *dpif, void *state,
 163                           struct dpif_port *port);
 164
 165     /* Releases resources from 'dpif' for 'state', which was initialized by a
 166      * successful call to the 'port_dump_start' function for 'dpif'.  */
 167     int (*port_dump_done)(const struct dpif *dpif, void *state);
 168
 169     /* Polls for changes in the set of ports in 'dpif'.  If the set of ports in
 170      * 'dpif' has changed, then this function should do one of the
 171      * following:
 172      *
 173      * - Preferably: store the name of the device that was added to or deleted
 174      *   from 'dpif' in '*devnamep' and return 0.  The caller is responsible
 175      *   for freeing '*devnamep' (with free()) when it no longer needs it.
 176      *
 177      * - Alternatively: return ENOBUFS, without indicating the device that was
 178      *   added or deleted.
 179      *
 180      * Occasional 'false positives', in which the function returns 0 while
 181      * indicating a device that was not actually added or deleted or returns
 182      * ENOBUFS without any change, are acceptable.
 183      *
 184      * If the set of ports in 'dpif' has not changed, returns EAGAIN.  May also
 185      * return other positive errno values to indicate that something has gone
 186      * wrong. */
 187     int (*port_poll)(const struct dpif *dpif, char **devnamep);
 188
 189     /* Arranges for the poll loop to wake up when 'port_poll' will return a
 190      * value other than EAGAIN. */
 191     void (*port_poll_wait)(const struct dpif *dpif);
 192
 193     /* Queries 'dpif' for a flow entry.  The flow is specified by the Netlink
 194      * attributes with types ODP_KEY_ATTR_* in the 'key_len' bytes starting at
 195      * 'key'.
 196      *
 197      * Returns 0 if successful.  If no flow matches, returns ENOENT.  On other
 198      * failure, returns a positive errno value.
 199      *
 200      * If 'actionsp' is nonnull, then on success '*actionsp' must be set to an
 201      * ofpbuf owned by the caller that contains the Netlink attributes for the
 202      * flow's actions.  The caller must free the ofpbuf (with ofpbuf_delete())
 203      * when it is no longer needed.
 204      *
 205      * If 'stats' is nonnull, then on success it must be updated with the
 206      * flow's statistics. */
 207     int (*flow_get)(const struct dpif *dpif,
 208                     const struct nlattr *key, size_t key_len,
 209                     struct ofpbuf **actionsp, struct dpif_flow_stats *stats);
 210
 211     /* Adds or modifies a flow in 'dpif'.  The flow is specified by the Netlink
 212      * attributes with types ODP_KEY_ATTR_* in the 'key_len' bytes starting at
 213      * 'key'.  The associated actions are specified by the Netlink attributes
 214      * with types ODPAT_* in the 'actions_len' bytes starting at 'actions'.
 215      *
 216      * - If the flow's key does not exist in 'dpif', then the flow will be
 217      *   added if 'flags' includes DPIF_FP_CREATE.  Otherwise the operation
 218      *   will fail with ENOENT.
 219      *
 220      *   If the operation succeeds, then 'stats', if nonnull, must be zeroed.
 221      *
 222      * - If the flow's key does exist in 'dpif', then the flow's actions will
 223      *   be updated if 'flags' includes DPIF_FP_MODIFY.  Otherwise the
 224      *   operation will fail with EEXIST.  If the flow's actions are updated,
 225      *   then its statistics will be zeroed if 'flags' includes
 226      *   DPIF_FP_ZERO_STATS, and left as-is otherwise.
 227      *
 228      *   If the operation succeeds, then 'stats', if nonnull, must be set to
 229      *   the flow's statistics before the update.
 230      */
 231     int (*flow_put)(struct dpif *dpif, enum dpif_flow_put_flags flags,
 232                     const struct nlattr *key, size_t key_len,
 233                     const struct nlattr *actions, size_t actions_len,
 234                     struct dpif_flow_stats *stats);
 235
 236     /* Deletes a flow from 'dpif' and returns 0, or returns ENOENT if 'dpif'
 237      * does not contain such a flow.  The flow is specified by the Netlink
 238      * attributes with types ODP_KEY_ATTR_* in the 'key_len' bytes starting at
 239      * 'key'.
 240      *
 241      * If the operation succeeds, then 'stats', if nonnull, must be set to the
 242      * flow's statistics before its deletion. */
 243     int (*flow_del)(struct dpif *dpif,
 244                     const struct nlattr *key, size_t key_len,
 245                     struct dpif_flow_stats *stats);
 246
 247     /* Deletes all flows from 'dpif' and clears all of its queues of received
 248      * packets. */
 249     int (*flow_flush)(struct dpif *dpif);
 250
 251     /* Attempts to begin dumping the flows in a dpif.  On success, returns 0
 252      * and initializes '*statep' with any data needed for iteration.  On
 253      * failure, returns a positive errno value. */
 254     int (*flow_dump_start)(const struct dpif *dpif, void **statep);
 255
 256     /* Attempts to retrieve another flow from 'dpif' for 'state', which was
 257      * initialized by a successful call to the 'flow_dump_start' function for
 258      * 'dpif'.  On success, updates the output parameters as described below
 259      * and returns 0.  Returns EOF if the end of the flow table has been
 260      * reached, or a positive errno value on error.  This function will not be
 261      * called again once it returns nonzero within a given iteration (but the
 262      * 'flow_dump_done' function will be called afterward).
 263      *
 264      * On success, if 'key' and 'key_len' are nonnull then '*key' and
 265      * '*key_len' must be set to Netlink attributes with types ODP_KEY_ATTR_*
 266      * representing the dumped flow's key.  If 'actions' and 'actions_len' are
 267      * nonnull then they should be set to Netlink attributes with types ODPAT_*
 268      * representing the dumped flow's actions.  If 'stats' is nonnull then it
 269      * should be set to the dumped flow's statistics.
 270      *
 271      * All of the returned data is owned by 'dpif', not by the caller, and the
 272      * caller must not modify or free it.  'dpif' must guarantee that it
 273      * remains accessible and unchanging until at least the next call to
 274      * 'flow_dump_next' or 'flow_dump_done' for 'state'. */
 275     int (*flow_dump_next)(const struct dpif *dpif, void *state,
 276                           const struct nlattr **key, size_t *key_len,
 277                           const struct nlattr **actions, size_t *actions_len,
 278                           const struct dpif_flow_stats **stats);
 279
 280     /* Releases resources from 'dpif' for 'state', which was initialized by a
 281      * successful call to the 'flow_dump_start' function for 'dpif'.  */
 282     int (*flow_dump_done)(const struct dpif *dpif, void *state);
 283
 284     /* Performs the 'actions_len' bytes of actions in 'actions' on the Ethernet
 285      * frame specified in 'packet'. */
 286     int (*execute)(struct dpif *dpif, const struct nlattr *actions,
 287                    size_t actions_len, const struct ofpbuf *packet);
 288
 289     /* Retrieves 'dpif''s "listen mask" into '*listen_mask'.  A 1-bit of value
 290      * 2**X set in '*listen_mask' indicates that 'dpif' will receive messages
 291      * of the type (from "enum dpif_upcall_type") with value X when its 'recv'
 292      * function is called. */
 293     int (*recv_get_mask)(const struct dpif *dpif, int *listen_mask);
 294
 295     /* Sets 'dpif''s "listen mask" to 'listen_mask'.  A 1-bit of value 2**X set
 296      * in '*listen_mask' requests that 'dpif' will receive messages of the type
 297      * (from "enum dpif_upcall_type") with value X when its 'recv' function is
 298      * called. */
 299     int (*recv_set_mask)(struct dpif *dpif, int listen_mask);
 300
 301     /* Retrieves 'dpif''s sFlow sampling probability into '*probability'.
 302      * Return value is 0 or a positive errno value.  EOPNOTSUPP indicates that
 303      * the datapath does not support sFlow, as does a null pointer.
 304      *
 305      * '*probability' is expressed as the number of packets out of UINT_MAX to
 306      * sample, e.g. probability/UINT_MAX is the probability of sampling a given
 307      * packet. */
 308     int (*get_sflow_probability)(const struct dpif *dpif,
 309                                  uint32_t *probability);
 310
 311     /* Sets 'dpif''s sFlow sampling probability to 'probability'.  Return value
 312      * is 0 or a positive errno value.  EOPNOTSUPP indicates that the datapath
 313      * does not support sFlow, as does a null pointer.
 314      *
 315      * 'probability' is expressed as the number of packets out of UINT_MAX to
 316      * sample, e.g. probability/UINT_MAX is the probability of sampling a given
 317      * packet. */
 318     int (*set_sflow_probability)(struct dpif *dpif, uint32_t probability);
 319
 320     /* Translates OpenFlow queue ID 'queue_id' (in host byte order) into a
 321      * priority value for use in the ODPAT_SET_PRIORITY action in
 322      * '*priority'. */
 323     int (*queue_to_priority)(const struct dpif *dpif, uint32_t queue_id,
 324                              uint32_t *priority);
 325
 326     /* Polls for an upcall from 'dpif'.  If successful, stores the upcall into
 327      * '*upcall'.  Only upcalls of the types selected with the set_listen_mask
 328      * member function should be received.
 329      *
 330      * The caller takes ownership of the data that 'upcall' points to.
 331      * 'upcall->key' and 'upcall->actions' (if nonnull) point into data owned
 332      * by 'upcall->packet', so their memory cannot be freed separately.  (This
 333      * is hardly a great way to do things but it works out OK for the dpif
 334      * providers that exist so far.)
 335      *
 336      * For greatest efficiency, 'upcall->packet' should have at least
 337      * offsetof(struct ofp_packet_in, data) bytes of headroom.
 338      *
 339      * This function must not block.  If no upcall is pending when it is
 340      * called, it should return EAGAIN without blocking. */
 341     int (*recv)(struct dpif *dpif, struct dpif_upcall *upcall);
 342
 343     /* Arranges for the poll loop to wake up when 'dpif' has a message queued
 344      * to be received with the recv member function. */
 345     void (*recv_wait)(struct dpif *dpif);
 346
 347     /* Throws away any queued upcalls that 'dpif' currently has ready to
 348      * return. */
 349     void (*recv_purge)(struct dpif *dpif);
 350 };
 351
 352 extern const struct dpif_class dpif_linux_class;
 353 extern const struct dpif_class dpif_netdev_class;
 354
 355 #ifdef  __cplusplus
 356 }
 357 #endif
 358
 359 #endif /* dpif-provider.h */