lib/dpif-provider.h

   1 /*
   2  * Copyright (c) 2009, 2010 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. */
  22
  23 #include <assert.h>
  24 #include "dpif.h"
  25
  26 /* Open vSwitch datapath interface.
  27  *
  28  * This structure should be treated as opaque by dpif implementations. */
  29 struct dpif {
  30     const struct dpif_class *class;
  31     char *base_name;
  32     char *full_name;
  33     uint8_t netflow_engine_type;
  34     uint8_t netflow_engine_id;
  35 };
  36
  37 void dpif_init(struct dpif *, const struct dpif_class *, const char *name,
  38                uint8_t netflow_engine_type, uint8_t netflow_engine_id);
  39 static inline void dpif_assert_class(const struct dpif *dpif,
  40                                      const struct dpif_class *class)
  41 {
  42     assert(dpif->class == class);
  43 }
  44
  45 /* Datapath interface class structure, to be defined by each implementation of
  46  * a datapath interface.
  47  *
  48  * These functions return 0 if successful or a positive errno value on failure,
  49  * except where otherwise noted.
  50  *
  51  * These functions are expected to execute synchronously, that is, to block as
  52  * necessary to obtain a result.  Thus, they may not return EAGAIN or
  53  * EWOULDBLOCK or EINPROGRESS.  We may relax this requirement in the future if
  54  * and when we encounter performance problems. */
  55 struct dpif_class {
  56     /* Type of dpif in this class, e.g. "system", "netdev", etc.
  57      *
  58      * One of the providers should supply a "system" type, since this is
  59      * the type assumed if no type is specified when opening a dpif. */
  60     const char *type;
  61
  62     /* Performs periodic work needed by dpifs of this class, if any is
  63      * necessary. */
  64     void (*run)(void);
  65
  66     /* Arranges for poll_block() to wake up if the "run" member function needs
  67      * to be called. */
  68     void (*wait)(void);
  69
  70     /* Enumerates the names of all known created datapaths, if possible, into
  71      * 'all_dps'.  The caller has already initialized 'all_dps' and other dpif
  72      * classes might already have added names to it.
  73      *
  74      * This is used by the vswitch at startup, so that it can delete any
  75      * datapaths that are not configured.
  76      *
  77      * Some kinds of datapaths might not be practically enumerable, in which
  78      * case this function may be a null pointer. */
  79     int (*enumerate)(struct svec *all_dps);
  80
  81     /* Attempts to open an existing dpif called 'name', if 'create' is false,
  82      * or to open an existing dpif or create a new one, if 'create' is true.
  83      * 'type' corresponds to the 'type' field used in the dpif_class
  84      * structure.
  85      *
  86      * If successful, stores a pointer to the new dpif in '*dpifp'.  On failure
  87      * there are no requirements on what is stored in '*dpifp'. */
  88     int (*open)(const char *name, const char *type, bool create,
  89                 struct dpif **dpifp);
  90
  91     /* Closes 'dpif' and frees associated memory. */
  92     void (*close)(struct dpif *dpif);
  93
  94     /* Enumerates all names that may be used to open 'dpif' into 'all_names'.
  95      * The Linux datapath, for example, supports opening a datapath both by
  96      * number, e.g. "dp0", and by the name of the datapath's local port.  For
  97      * some datapaths, this might be an infinite set (e.g. in a file name,
  98      * slashes may be duplicated any number of times), in which case only the
  99      * names most likely to be used should be enumerated.
 100      *
 101      * The caller has already initialized 'all_names' and might already have
 102      * added some names to it.  This function should not disturb any existing
 103      * names in 'all_names'.
 104      *
 105      * If a datapath class does not support multiple names for a datapath, this
 106      * function may be a null pointer.
 107      *
 108      * This is used by the vswitch at startup, */
 109     int (*get_all_names)(const struct dpif *dpif, struct svec *all_names);
 110
 111     /* Attempts to destroy the dpif underlying 'dpif'.
 112      *
 113      * If successful, 'dpif' will not be used again except as an argument for
 114      * the 'close' member function. */
 115     int (*delete)(struct dpif *dpif);
 116
 117     /* Retrieves statistics for 'dpif' into 'stats'. */
 118     int (*get_stats)(const struct dpif *dpif, struct odp_stats *stats);
 119
 120     /* Retrieves 'dpif''s current treatment of IP fragments into '*drop_frags':
 121      * true indicates that fragments are dropped, false indicates that
 122      * fragments are treated in the same way as other IP packets (except that
 123      * the L4 header cannot be read). */
 124     int (*get_drop_frags)(const struct dpif *dpif, bool *drop_frags);
 125
 126     /* Changes 'dpif''s treatment of IP fragments to 'drop_frags', whose
 127      * meaning is the same as for the get_drop_frags member function. */
 128     int (*set_drop_frags)(struct dpif *dpif, bool drop_frags);
 129
 130     /* Creates a new port in 'dpif' connected to network device 'devname'.
 131      * 'flags' is a set of ODP_PORT_* flags.  If successful, sets '*port_no'
 132      * to the new port's port number. */
 133     int (*port_add)(struct dpif *dpif, const char *devname, uint16_t flags,
 134                     uint16_t *port_no);
 135
 136     /* Removes port numbered 'port_no' from 'dpif'. */
 137     int (*port_del)(struct dpif *dpif, uint16_t port_no);
 138
 139     /* Queries 'dpif' for a port with the given 'port_no' or 'devname'.  Stores
 140      * information about the port into '*port' if successful. */
 141     int (*port_query_by_number)(const struct dpif *dpif, uint16_t port_no,
 142                                 struct odp_port *port);
 143     int (*port_query_by_name)(const struct dpif *dpif, const char *devname,
 144                               struct odp_port *port);
 145
 146     /* Stores in 'ports' information about up to 'n' ports attached to 'dpif',
 147      * in no particular order.  Returns the number of ports attached to 'dpif'
 148      * (not the number stored), if successful, otherwise a negative errno
 149      * value. */
 150     int (*port_list)(const struct dpif *dpif, struct odp_port *ports, int n);
 151
 152     /* Polls for changes in the set of ports in 'dpif'.  If the set of ports in
 153      * 'dpif' has changed, then this function should do one of the
 154      * following:
 155      *
 156      * - Preferably: store the name of the device that was added to or deleted
 157      *   from 'dpif' in '*devnamep' and return 0.  The caller is responsible
 158      *   for freeing '*devnamep' (with free()) when it no longer needs it.
 159      *
 160      * - Alternatively: return ENOBUFS, without indicating the device that was
 161      *   added or deleted.
 162      *
 163      * Occasional 'false positives', in which the function returns 0 while
 164      * indicating a device that was not actually added or deleted or returns
 165      * ENOBUFS without any change, are acceptable.
 166      *
 167      * If the set of ports in 'dpif' has not changed, returns EAGAIN.  May also
 168      * return other positive errno values to indicate that something has gone
 169      * wrong. */
 170     int (*port_poll)(const struct dpif *dpif, char **devnamep);
 171
 172     /* Arranges for the poll loop to wake up when 'port_poll' will return a
 173      * value other than EAGAIN. */
 174     void (*port_poll_wait)(const struct dpif *dpif);
 175
 176     /* Stores in 'ports' the port numbers of up to 'n' ports that belong to
 177      * 'group' in 'dpif'.  Returns the number of ports in 'group' (not the
 178      * number stored), if successful, otherwise a negative errno value. */
 179     int (*port_group_get)(const struct dpif *dpif, int group,
 180                           uint16_t ports[], int n);
 181
 182     /* Changes port group 'group' in 'dpif' to consist of the 'n' ports whose
 183      * numbers are given in 'ports'.
 184      *
 185      * Use the get_stats member function to obtain the number of supported port
 186      * groups. */
 187     int (*port_group_set)(struct dpif *dpif, int group,
 188                           const uint16_t ports[], int n);
 189
 190     /* For each flow 'flow' in the 'n' flows in 'flows':
 191      *
 192      * - If a flow matching 'flow->key' exists in 'dpif':
 193      *
 194      *     Stores 0 into 'flow->stats.error' and stores statistics for the flow
 195      *     into 'flow->stats'.
 196      *
 197      *     If 'flow->n_actions' is zero, then 'flow->actions' is ignored.  If
 198      *     'flow->n_actions' is nonzero, then 'flow->actions' should point to
 199      *     an array of the specified number of actions.  At most that many of
 200      *     the flow's actions will be copied into that array.
 201      *     'flow->n_actions' will be updated to the number of actions actually
 202      *     present in the flow, which may be greater than the number stored if
 203      *     the flow has more actions than space available in the array.
 204      *
 205      * - Flow-specific errors are indicated by a positive errno value in
 206      *   'flow->stats.error'.  In particular, ENOENT indicates that no flow
 207      *   matching 'flow->key' exists in 'dpif'.  When an error value is stored,
 208      *   the contents of 'flow->key' are preserved but other members of 'flow'
 209      *   should be treated as indeterminate.
 210      *
 211      * Returns 0 if all 'n' flows in 'flows' were updated (whether they were
 212      * individually successful or not is indicated by 'flow->stats.error',
 213      * however).  Returns a positive errno value if an error that prevented
 214      * this update occurred, in which the caller must not depend on any
 215      * elements in 'flows' being updated or not updated.
 216      */
 217     int (*flow_get)(const struct dpif *dpif, struct odp_flow flows[], int n);
 218
 219     /* Adds or modifies a flow in 'dpif' as specified in 'put':
 220      *
 221      * - If the flow specified in 'put->flow' does not exist in 'dpif', then
 222      *   behavior depends on whether ODPPF_CREATE is specified in 'put->flags':
 223      *   if it is, the flow will be added, otherwise the operation will fail
 224      *   with ENOENT.
 225      *
 226      * - Otherwise, the flow specified in 'put->flow' does exist in 'dpif'.
 227      *   Behavior in this case depends on whether ODPPF_MODIFY is specified in
 228      *   'put->flags': if it is, the flow's actions will be updated, otherwise
 229      *   the operation will fail with EEXIST.  If the flow's actions are
 230      *   updated, then its statistics will be zeroed if ODPPF_ZERO_STATS is set
 231      *   in 'put->flags', left as-is otherwise.
 232      */
 233     int (*flow_put)(struct dpif *dpif, struct odp_flow_put *put);
 234
 235     /* Deletes a flow matching 'flow->key' from 'dpif' or returns ENOENT if
 236      * 'dpif' does not contain such a flow.
 237      *
 238      * If successful, updates 'flow->stats', 'flow->n_actions', and
 239      * 'flow->actions' as described in more detail under the flow_get member
 240      * function below. */
 241     int (*flow_del)(struct dpif *dpif, struct odp_flow *flow);
 242
 243     /* Deletes all flows from 'dpif' and clears all of its queues of received
 244      * packets. */
 245     int (*flow_flush)(struct dpif *dpif);
 246
 247     /* Stores up to 'n' flows in 'dpif' into 'flows', updating their statistics
 248      * and actions as described under the flow_get member function.  If
 249      * successful, returns the number of flows actually present in 'dpif',
 250      * which might be greater than the number stored (if 'dpif' has more than
 251      * 'n' flows).  On failure, returns a negative errno value. */
 252     int (*flow_list)(const struct dpif *dpif, struct odp_flow flows[], int n);
 253
 254     /* Performs the 'n_actions' actions in 'actions' on the Ethernet frame
 255      * specified in 'packet'.
 256      *
 257      * Pretends that the frame was originally received on the port numbered
 258      * 'in_port'.  This affects only ODPAT_OUTPUT_GROUP actions, which will not
 259      * send a packet out their input port.  Specify the number of an unused
 260      * port (e.g. UINT16_MAX is currently always unused) to avoid this
 261      * behavior. */
 262     int (*execute)(struct dpif *dpif, uint16_t in_port,
 263                    const union odp_action actions[], int n_actions,
 264                    const struct ofpbuf *packet);
 265
 266     /* Retrieves 'dpif''s "listen mask" into '*listen_mask'.  Each ODPL_* bit
 267      * set in '*listen_mask' indicates the 'dpif' will receive messages of the
 268      * corresponding type when it calls the recv member function. */
 269     int (*recv_get_mask)(const struct dpif *dpif, int *listen_mask);
 270
 271     /* Sets 'dpif''s "listen mask" to 'listen_mask'.  Each ODPL_* bit set in
 272      * 'listen_mask' indicates the 'dpif' will receive messages of the
 273      * corresponding type when it calls the recv member function. */
 274     int (*recv_set_mask)(struct dpif *dpif, int listen_mask);
 275
 276     /* Attempts to receive a message from 'dpif'.  If successful, stores the
 277      * message into '*packetp'.  The message, if one is received, must begin
 278      * with 'struct odp_msg' as a header.  Only messages of the types selected
 279      * with the set_listen_mask member function should be received.
 280      *
 281      * This function must not block.  If no message is ready to be received
 282      * when it is called, it should return EAGAIN without blocking. */
 283     int (*recv)(struct dpif *dpif, struct ofpbuf **packetp);
 284
 285     /* Arranges for the poll loop to wake up when 'dpif' has a message queued
 286      * to be received with the recv member function. */
 287     void (*recv_wait)(struct dpif *dpif);
 288 };
 289
 290 extern const struct dpif_class dpif_linux_class;
 291 extern const struct dpif_class dpif_netdev_class;
 292
 293 #endif /* dpif-provider.h */