lib/netdev-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 NETDEV_PROVIDER_H
  18 #define NETDEV_PROVIDER_H 1
  19
  20 /* Generic interface to network devices. */
  21
  22 #include <assert.h>
  23
  24 #include "netdev.h"
  25 #include "list.h"
  26 #include "shash.h"
  27 #include "smap.h"
  28
  29 #ifdef  __cplusplus
  30 extern "C" {
  31 #endif
  32
  33 /* A network device (e.g. an Ethernet device).
  34  *
  35  * This structure should be treated as opaque by network device
  36  * implementations. */
  37 struct netdev_dev {
  38     char *name;                         /* Name of network device. */
  39     const struct netdev_class *netdev_class; /* Functions to control
  40                                                 this device. */
  41     int ref_cnt;                        /* Times this devices was opened. */
  42     struct shash_node *node;            /* Pointer to element in global map. */
  43 };
  44
  45 void netdev_dev_init(struct netdev_dev *, const char *name,
  46                      const struct netdev_class *);
  47 void netdev_dev_uninit(struct netdev_dev *, bool destroy);
  48 const char *netdev_dev_get_type(const struct netdev_dev *);
  49 const struct netdev_class *netdev_dev_get_class(const struct netdev_dev *);
  50 const char *netdev_dev_get_name(const struct netdev_dev *);
  51 struct netdev_dev *netdev_dev_from_name(const char *name);
  52 void netdev_dev_get_devices(const struct netdev_class *,
  53                             struct shash *device_list);
  54
  55 static inline void netdev_dev_assert_class(const struct netdev_dev *netdev_dev,
  56                                            const struct netdev_class *class_)
  57 {
  58     assert(netdev_dev->netdev_class == class_);
  59 }
  60
  61 /* A instance of an open network device.
  62  *
  63  * This structure should be treated as opaque by network device
  64  * implementations. */
  65 struct netdev {
  66     struct netdev_dev *netdev_dev;   /* Parent netdev_dev. */
  67     struct list node;                /* Element in global list. */
  68
  69     enum netdev_flags save_flags;    /* Initial device flags. */
  70     enum netdev_flags changed_flags; /* Flags that we changed. */
  71 };
  72
  73 void netdev_init(struct netdev *, struct netdev_dev *);
  74 void netdev_uninit(struct netdev *, bool close);
  75 struct netdev_dev *netdev_get_dev(const struct netdev *);
  76
  77 static inline void netdev_assert_class(const struct netdev *netdev,
  78                                        const struct netdev_class *netdev_class)
  79 {
  80     netdev_dev_assert_class(netdev_get_dev(netdev), netdev_class);
  81 }
  82
  83 /* Network device class structure, to be defined by each implementation of a
  84  * network device.
  85  *
  86  * These functions return 0 if successful or a positive errno value on failure,
  87  * except where otherwise noted. */
  88 struct netdev_class {
  89     /* Type of netdevs in this class, e.g. "system", "tap", "gre", etc.
  90      *
  91      * One of the providers should supply a "system" type, since this is
  92      * the type assumed if no type is specified when opening a netdev.
  93      * The "system" type corresponds to an existing network device on
  94      * the system. */
  95     const char *type;
  96
  97     /* Called when the netdev provider is registered, typically at program
  98      * startup.  Returning an error from this function will prevent any network
  99      * device in this class from being opened.
 100      *
 101      * This function may be set to null if a network device class needs no
 102      * initialization at registration time. */
 103     int (*init)(void);
 104
 105     /* Performs periodic work needed by netdevs of this class.  May be null if
 106      * no periodic work is necessary. */
 107     void (*run)(void);
 108
 109     /* Arranges for poll_block() to wake up if the "run" member function needs
 110      * to be called.  Implementations are additionally required to wake
 111      * whenever something changes in any of its netdevs which would cause their
 112      * ->change_seq() function to change its result.  May be null if nothing is
 113      * needed here. */
 114     void (*wait)(void);
 115
 116     /* Attempts to create a network device named 'name' in 'netdev_class'.  On
 117      * success sets 'netdev_devp' to the newly created device. */
 118     int (*create)(const struct netdev_class *netdev_class, const char *name,
 119                   struct netdev_dev **netdev_devp);
 120
 121     /* Destroys 'netdev_dev'.
 122      *
 123      * Netdev devices maintain a reference count that is incremented on
 124      * netdev_open() and decremented on netdev_close().  If 'netdev_dev'
 125      * has a non-zero reference count, then this function will not be
 126      * called. */
 127     void (*destroy)(struct netdev_dev *netdev_dev);
 128
 129     /* Fetches the device 'netdev_dev''s configuration, storing it in 'args'.
 130      * The caller owns 'args' and pre-initializes it to an empty smap.
 131      *
 132      * If this netdev class does not have any configuration options, this may
 133      * be a null pointer. */
 134     int (*get_config)(struct netdev_dev *netdev_dev, struct smap *args);
 135
 136     /* Changes the device 'netdev_dev''s configuration to 'args'.
 137      *
 138      * If this netdev class does not support configuration, this may be a null
 139      * pointer. */
 140     int (*set_config)(struct netdev_dev *netdev_dev, const struct smap *args);
 141
 142     /* Returns the tunnel configuration of 'netdev_dev'.  If 'netdev_dev' is
 143      * not a tunnel, returns null.
 144      *
 145      * If this function would always return null, it may be null instead. */
 146     const struct netdev_tunnel_config *
 147         (*get_tunnel_config)(const struct netdev_dev *netdev_dev);
 148
 149     /* Attempts to open a network device.  On success, sets 'netdevp'
 150      * to the new network device. */
 151     int (*open)(struct netdev_dev *netdev_dev, struct netdev **netdevp);
 152
 153     /* Closes 'netdev'. */
 154     void (*close)(struct netdev *netdev);
 155 \f
 156 /* ## ----------------- ## */
 157 /* ## Receiving Packets ## */
 158 /* ## ----------------- ## */
 159
 160 /* The network provider interface is mostly used for inspecting and configuring
 161  * device "metadata", not for sending and receiving packets directly.  It may
 162  * be impractical to implement these functions on some operating systems and
 163  * hardware.  These functions may all be NULL in such cases.
 164  *
 165  * (However, the "dpif-netdev" implementation, which is the easiest way to
 166  * integrate Open vSwitch with a new operating system or hardware, does require
 167  * the ability to receive packets.) */
 168
 169     /* Attempts to set up 'netdev' for receiving packets with ->recv().
 170      * Returns 0 if successful, otherwise a positive errno value.  Return
 171      * EOPNOTSUPP to indicate that the network device does not implement packet
 172      * reception through this interface.  This function may be set to null if
 173      * it would always return EOPNOTSUPP anyhow.  (This will prevent the
 174      * network device from being usefully used by the netdev-based "userspace
 175      * datapath".)*/
 176     int (*listen)(struct netdev *netdev);
 177
 178     /* Attempts to receive a packet from 'netdev' into the 'size' bytes in
 179      * 'buffer'.  If successful, returns the number of bytes in the received
 180      * packet, otherwise a negative errno value.  Returns -EAGAIN immediately
 181      * if no packet is ready to be received.
 182      *
 183      * Returns -EMSGSIZE, and discards the packet, if the received packet is
 184      * longer than 'size' bytes.
 185      *
 186      * This function can only be expected to return a packet if ->listen() has
 187      * been called successfully.
 188      *
 189      * May be null if not needed, such as for a network device that does not
 190      * implement packet reception through the 'recv' member function. */
 191     int (*recv)(struct netdev *netdev, void *buffer, size_t size);
 192
 193     /* Registers with the poll loop to wake up from the next call to
 194      * poll_block() when a packet is ready to be received with netdev_recv() on
 195      * 'netdev'.
 196      *
 197      * May be null if not needed, such as for a network device that does not
 198      * implement packet reception through the 'recv' member function. */
 199     void (*recv_wait)(struct netdev *netdev);
 200
 201     /* Discards all packets waiting to be received from 'netdev'.
 202      *
 203      * May be null if not needed, such as for a network device that does not
 204      * implement packet reception through the 'recv' member function. */
 205     int (*drain)(struct netdev *netdev);
 206 \f
 207     /* Sends the 'size'-byte packet in 'buffer' on 'netdev'.  Returns 0 if
 208      * successful, otherwise a positive errno value.  Returns EAGAIN without
 209      * blocking if the packet cannot be queued immediately.  Returns EMSGSIZE
 210      * if a partial packet was transmitted or if the packet is too big or too
 211      * small to transmit on the device.
 212      *
 213      * The caller retains ownership of 'buffer' in all cases.
 214      *
 215      * The network device is expected to maintain a packet transmission queue,
 216      * so that the caller does not ordinarily have to do additional queuing of
 217      * packets.
 218      *
 219      * May return EOPNOTSUPP if a network device does not implement packet
 220      * transmission through this interface.  This function may be set to null
 221      * if it would always return EOPNOTSUPP anyhow.  (This will prevent the
 222      * network device from being usefully used by the netdev-based "userspace
 223      * datapath".  It will also prevent the OVS implementation of bonding from
 224      * working properly over 'netdev'.) */
 225     int (*send)(struct netdev *netdev, const void *buffer, size_t size);
 226
 227     /* Registers with the poll loop to wake up from the next call to
 228      * poll_block() when the packet transmission queue for 'netdev' has
 229      * sufficient room to transmit a packet with netdev_send().
 230      *
 231      * The network device is expected to maintain a packet transmission queue,
 232      * so that the caller does not ordinarily have to do additional queuing of
 233      * packets.  Thus, this function is unlikely to ever be useful.
 234      *
 235      * May be null if not needed, such as for a network device that does not
 236      * implement packet transmission through the 'send' member function. */
 237     void (*send_wait)(struct netdev *netdev);
 238
 239     /* Sets 'netdev''s Ethernet address to 'mac' */
 240     int (*set_etheraddr)(struct netdev *netdev, const uint8_t mac[6]);
 241
 242     /* Retrieves 'netdev''s Ethernet address into 'mac'.
 243      *
 244      * This address will be advertised as 'netdev''s MAC address through the
 245      * OpenFlow protocol, among other uses. */
 246     int (*get_etheraddr)(const struct netdev *netdev, uint8_t mac[6]);
 247
 248     /* Retrieves 'netdev''s MTU into '*mtup'.
 249      *
 250      * The MTU is the maximum size of transmitted (and received) packets, in
 251      * bytes, not including the hardware header; thus, this is typically 1500
 252      * bytes for Ethernet devices.
 253      *
 254      * If 'netdev' does not have an MTU (e.g. as some tunnels do not), then
 255      * this function should return EOPNOTSUPP.  This function may be set to
 256      * null if it would always return EOPNOTSUPP. */
 257     int (*get_mtu)(const struct netdev *netdev, int *mtup);
 258
 259     /* Sets 'netdev''s MTU to 'mtu'.
 260      *
 261      * If 'netdev' does not have an MTU (e.g. as some tunnels do not), then
 262      * this function should return EOPNOTSUPP.  This function may be set to
 263      * null if it would always return EOPNOTSUPP. */
 264     int (*set_mtu)(const struct netdev *netdev, int mtu);
 265
 266     /* Returns the ifindex of 'netdev', if successful, as a positive number.
 267      * On failure, returns a negative errno value.
 268      *
 269      * The desired semantics of the ifindex value are a combination of those
 270      * specified by POSIX for if_nametoindex() and by SNMP for ifIndex.  An
 271      * ifindex value should be unique within a host and remain stable at least
 272      * until reboot.  SNMP says an ifindex "ranges between 1 and the value of
 273      * ifNumber" but many systems do not follow this rule anyhow.
 274      *
 275      * This function may be set to null if it would always return -EOPNOTSUPP.
 276      */
 277     int (*get_ifindex)(const struct netdev *netdev);
 278
 279     /* Sets 'carrier' to true if carrier is active (link light is on) on
 280      * 'netdev'.
 281      *
 282      * May be null if device does not provide carrier status (will be always
 283      * up as long as device is up).
 284      */
 285     int (*get_carrier)(const struct netdev *netdev, bool *carrier);
 286
 287     /* Returns the number of times 'netdev''s carrier has changed since being
 288      * initialized.
 289      *
 290      * If null, callers will assume the number of carrier resets is zero. */
 291     long long int (*get_carrier_resets)(const struct netdev *netdev);
 292
 293     /* Forces ->get_carrier() to poll 'netdev''s MII registers for link status
 294      * instead of checking 'netdev''s carrier.  'netdev''s MII registers will
 295      * be polled once ever 'interval' milliseconds.  If 'netdev' does not
 296      * support MII, another method may be used as a fallback.  If 'interval' is
 297      * less than or equal to zero, reverts ->get_carrier() to its normal
 298      * behavior.
 299      *
 300      * Most network devices won't support this feature and will set this
 301      * function pointer to NULL, which is equivalent to returning EOPNOTSUPP.
 302      */
 303     int (*set_miimon_interval)(struct netdev *netdev, long long int interval);
 304
 305     /* Retrieves current device stats for 'netdev' into 'stats'.
 306      *
 307      * A network device that supports some statistics but not others, it should
 308      * set the values of the unsupported statistics to all-1-bits
 309      * (UINT64_MAX). */
 310     int (*get_stats)(const struct netdev *netdev, struct netdev_stats *);
 311
 312     /* Sets the device stats for 'netdev' to 'stats'.
 313      *
 314      * Most network devices won't support this feature and will set this
 315      * function pointer to NULL, which is equivalent to returning EOPNOTSUPP.
 316      *
 317      * Some network devices might only allow setting their stats to 0. */
 318     int (*set_stats)(struct netdev *netdev, const struct netdev_stats *);
 319
 320     /* Stores the features supported by 'netdev' into each of '*current',
 321      * '*advertised', '*supported', and '*peer'.  Each value is a bitmap of
 322      * NETDEV_F_* bits.
 323      *
 324      * This function may be set to null if it would always return EOPNOTSUPP.
 325      */
 326     int (*get_features)(const struct netdev *netdev,
 327                         enum netdev_features *current,
 328                         enum netdev_features *advertised,
 329                         enum netdev_features *supported,
 330                         enum netdev_features *peer);
 331
 332     /* Set the features advertised by 'netdev' to 'advertise', which is a
 333      * set of NETDEV_F_* bits.
 334      *
 335      * This function may be set to null for a network device that does not
 336      * support configuring advertisements. */
 337     int (*set_advertisements)(struct netdev *netdev,
 338                               enum netdev_features advertise);
 339
 340     /* Attempts to set input rate limiting (policing) policy, such that up to
 341      * 'kbits_rate' kbps of traffic is accepted, with a maximum accumulative
 342      * burst size of 'kbits' kb.
 343      *
 344      * This function may be set to null if policing is not supported. */
 345     int (*set_policing)(struct netdev *netdev, unsigned int kbits_rate,
 346                         unsigned int kbits_burst);
 347
 348     /* Adds to 'types' all of the forms of QoS supported by 'netdev', or leaves
 349      * it empty if 'netdev' does not support QoS.  Any names added to 'types'
 350      * should be documented as valid for the "type" column in the "QoS" table
 351      * in vswitchd/vswitch.xml (which is built as ovs-vswitchd.conf.db(8)).
 352      *
 353      * Every network device must support disabling QoS with a type of "", but
 354      * this function must not add "" to 'types'.
 355      *
 356      * The caller is responsible for initializing 'types' (e.g. with
 357      * sset_init()) before calling this function.  The caller retains ownership
 358      * of 'types'.
 359      *
 360      * May be NULL if 'netdev' does not support QoS at all. */
 361     int (*get_qos_types)(const struct netdev *netdev, struct sset *types);
 362
 363     /* Queries 'netdev' for its capabilities regarding the specified 'type' of
 364      * QoS.  On success, initializes 'caps' with the QoS capabilities.
 365      *
 366      * Should return EOPNOTSUPP if 'netdev' does not support 'type'.  May be
 367      * NULL if 'netdev' does not support QoS at all. */
 368     int (*get_qos_capabilities)(const struct netdev *netdev,
 369                                 const char *type,
 370                                 struct netdev_qos_capabilities *caps);
 371
 372     /* Queries 'netdev' about its currently configured form of QoS.  If
 373      * successful, stores the name of the current form of QoS into '*typep'
 374      * and any details of configuration as string key-value pairs in
 375      * 'details'.
 376      *
 377      * A '*typep' of "" indicates that QoS is currently disabled on 'netdev'.
 378      *
 379      * The caller initializes 'details' before calling this function.  The
 380      * caller takes ownership of the string key-values pairs added to
 381      * 'details'.
 382      *
 383      * The netdev retains ownership of '*typep'.
 384      *
 385      * '*typep' will be one of the types returned by netdev_get_qos_types() for
 386      * 'netdev'.  The contents of 'details' should be documented as valid for
 387      * '*typep' in the "other_config" column in the "QoS" table in
 388      * vswitchd/vswitch.xml (which is built as ovs-vswitchd.conf.db(8)).
 389      *
 390      * May be NULL if 'netdev' does not support QoS at all. */
 391     int (*get_qos)(const struct netdev *netdev,
 392                    const char **typep, struct smap *details);
 393
 394     /* Attempts to reconfigure QoS on 'netdev', changing the form of QoS to
 395      * 'type' with details of configuration from 'details'.
 396      *
 397      * On error, the previous QoS configuration is retained.
 398      *
 399      * When this function changes the type of QoS (not just 'details'), this
 400      * also resets all queue configuration for 'netdev' to their defaults
 401      * (which depend on the specific type of QoS).  Otherwise, the queue
 402      * configuration for 'netdev' is unchanged.
 403      *
 404      * 'type' should be "" (to disable QoS) or one of the types returned by
 405      * netdev_get_qos_types() for 'netdev'.  The contents of 'details' should
 406      * be documented as valid for the given 'type' in the "other_config" column
 407      * in the "QoS" table in vswitchd/vswitch.xml (which is built as
 408      * ovs-vswitchd.conf.db(8)).
 409      *
 410      * May be NULL if 'netdev' does not support QoS at all. */
 411     int (*set_qos)(struct netdev *netdev,
 412                    const char *type, const struct smap *details);
 413
 414     /* Queries 'netdev' for information about the queue numbered 'queue_id'.
 415      * If successful, adds that information as string key-value pairs to
 416      * 'details'.  Returns 0 if successful, otherwise a positive errno value.
 417      *
 418      * Should return EINVAL if 'queue_id' is greater than or equal to the
 419      * number of supported queues (as reported in the 'n_queues' member of
 420      * struct netdev_qos_capabilities by 'get_qos_capabilities').
 421      *
 422      * The caller initializes 'details' before calling this function.  The
 423      * caller takes ownership of the string key-values pairs added to
 424      * 'details'.
 425      *
 426      * The returned contents of 'details' should be documented as valid for the
 427      * given 'type' in the "other_config" column in the "Queue" table in
 428      * vswitchd/vswitch.xml (which is built as ovs-vswitchd.conf.db(8)).
 429      */
 430     int (*get_queue)(const struct netdev *netdev,
 431                      unsigned int queue_id, struct smap *details);
 432
 433     /* Configures the queue numbered 'queue_id' on 'netdev' with the key-value
 434      * string pairs in 'details'.  The contents of 'details' should be
 435      * documented as valid for the given 'type' in the "other_config" column in
 436      * the "Queue" table in vswitchd/vswitch.xml (which is built as
 437      * ovs-vswitchd.conf.db(8)).  Returns 0 if successful, otherwise a positive
 438      * errno value.  On failure, the given queue's configuration should be
 439      * unmodified.
 440      *
 441      * Should return EINVAL if 'queue_id' is greater than or equal to the
 442      * number of supported queues (as reported in the 'n_queues' member of
 443      * struct netdev_qos_capabilities by 'get_qos_capabilities'), or if
 444      * 'details' is invalid for the type of queue.
 445      *
 446      * This function does not modify 'details', and the caller retains
 447      * ownership of it.
 448      *
 449      * May be NULL if 'netdev' does not support QoS at all. */
 450     int (*set_queue)(struct netdev *netdev,
 451                      unsigned int queue_id, const struct smap *details);
 452
 453     /* Attempts to delete the queue numbered 'queue_id' from 'netdev'.
 454      *
 455      * Should return EINVAL if 'queue_id' is greater than or equal to the
 456      * number of supported queues (as reported in the 'n_queues' member of
 457      * struct netdev_qos_capabilities by 'get_qos_capabilities').  Should
 458      * return EOPNOTSUPP if 'queue_id' is valid but may not be deleted (e.g. if
 459      * 'netdev' has a fixed set of queues with the current QoS mode).
 460      *
 461      * May be NULL if 'netdev' does not support QoS at all, or if all of its
 462      * QoS modes have fixed sets of queues. */
 463     int (*delete_queue)(struct netdev *netdev, unsigned int queue_id);
 464
 465     /* Obtains statistics about 'queue_id' on 'netdev'.  Fills 'stats' with the
 466      * queue's statistics.  May set individual members of 'stats' to all-1-bits
 467      * if the statistic is unavailable.
 468      *
 469      * May be NULL if 'netdev' does not support QoS at all. */
 470     int (*get_queue_stats)(const struct netdev *netdev, unsigned int queue_id,
 471                            struct netdev_queue_stats *stats);
 472
 473     /* Iterates over all of 'netdev''s queues, calling 'cb' with the queue's
 474      * ID, its configuration, and the 'aux' specified by the caller.  The order
 475      * of iteration is unspecified, but (when successful) each queue is visited
 476      * exactly once.
 477      *
 478      * 'cb' will not modify or free the 'details' argument passed in.  It may
 479      * delete or modify the queue passed in as its 'queue_id' argument.  It may
 480      * modify but will not delete any other queue within 'netdev'.  If 'cb'
 481      * adds new queues, then ->dump_queues is allowed to visit some queues
 482      * twice or not at all.
 483      */
 484     int (*dump_queues)(const struct netdev *netdev,
 485                        void (*cb)(unsigned int queue_id,
 486                                   const struct smap *details,
 487                                   void *aux),
 488                        void *aux);
 489
 490     /* Iterates over all of 'netdev''s queues, calling 'cb' with the queue's
 491      * ID, its statistics, and the 'aux' specified by the caller.  The order of
 492      * iteration is unspecified, but (when successful) each queue must be
 493      * visited exactly once.
 494      *
 495      * 'cb' will not modify or free the statistics passed in. */
 496     int (*dump_queue_stats)(const struct netdev *netdev,
 497                             void (*cb)(unsigned int queue_id,
 498                                        struct netdev_queue_stats *,
 499                                        void *aux),
 500                             void *aux);
 501
 502     /* If 'netdev' has an assigned IPv4 address, sets '*address' to that
 503      * address and '*netmask' to the associated netmask.
 504      *
 505      * The following error values have well-defined meanings:
 506      *
 507      *   - EADDRNOTAVAIL: 'netdev' has no assigned IPv4 address.
 508      *
 509      *   - EOPNOTSUPP: No IPv4 network stack attached to 'netdev'.
 510      *
 511      * This function may be set to null if it would always return EOPNOTSUPP
 512      * anyhow. */
 513     int (*get_in4)(const struct netdev *netdev, struct in_addr *address,
 514                    struct in_addr *netmask);
 515
 516     /* Assigns 'addr' as 'netdev''s IPv4 address and 'mask' as its netmask.  If
 517      * 'addr' is INADDR_ANY, 'netdev''s IPv4 address is cleared.
 518      *
 519      * This function may be set to null if it would always return EOPNOTSUPP
 520      * anyhow. */
 521     int (*set_in4)(struct netdev *netdev, struct in_addr addr,
 522                    struct in_addr mask);
 523
 524     /* If 'netdev' has an assigned IPv6 address, sets '*in6' to that address.
 525      *
 526      * The following error values have well-defined meanings:
 527      *
 528      *   - EADDRNOTAVAIL: 'netdev' has no assigned IPv6 address.
 529      *
 530      *   - EOPNOTSUPP: No IPv6 network stack attached to 'netdev'.
 531      *
 532      * This function may be set to null if it would always return EOPNOTSUPP
 533      * anyhow. */
 534     int (*get_in6)(const struct netdev *netdev, struct in6_addr *in6);
 535
 536     /* Adds 'router' as a default IP gateway for the TCP/IP stack that
 537      * corresponds to 'netdev'.
 538      *
 539      * This function may be set to null if it would always return EOPNOTSUPP
 540      * anyhow. */
 541     int (*add_router)(struct netdev *netdev, struct in_addr router);
 542
 543     /* Looks up the next hop for 'host'.  If succesful, stores the next hop
 544      * gateway's address (0 if 'host' is on a directly connected network) in
 545      * '*next_hop' and a copy of the name of the device to reach 'host' in
 546      * '*netdev_name', and returns 0.  The caller is responsible for freeing
 547      * '*netdev_name' (by calling free()).
 548      *
 549      * This function may be set to null if it would always return EOPNOTSUPP
 550      * anyhow. */
 551     int (*get_next_hop)(const struct in_addr *host, struct in_addr *next_hop,
 552                         char **netdev_name);
 553
 554     /* Retrieves driver information of the device.
 555      *
 556      * Populates 'smap' with key-value pairs representing the status of the
 557      * device.  'smap' is a set of key-value string pairs representing netdev
 558      * type specific information.  For more information see
 559      * ovs-vswitchd.conf.db(5).
 560      *
 561      * The caller is responsible for destroying 'smap' and its data.
 562      *
 563      * This function may be set to null if it would always return EOPNOTSUPP
 564      * anyhow. */
 565     int (*get_status)(const struct netdev *netdev, struct smap *smap);
 566
 567     /* Looks up the ARP table entry for 'ip' on 'netdev' and stores the
 568      * corresponding MAC address in 'mac'.  A return value of ENXIO, in
 569      * particular, indicates that there is no ARP table entry for 'ip' on
 570      * 'netdev'.
 571      *
 572      * This function may be set to null if it would always return EOPNOTSUPP
 573      * anyhow. */
 574     int (*arp_lookup)(const struct netdev *netdev, ovs_be32 ip,
 575                       uint8_t mac[6]);
 576
 577     /* Retrieves the current set of flags on 'netdev' into '*old_flags'.
 578      * Then, turns off the flags that are set to 1 in 'off' and turns on the
 579      * flags that are set to 1 in 'on'.  (No bit will be set to 1 in both 'off'
 580      * and 'on'; that is, off & on == 0.)
 581      *
 582      * This function may be invoked from a signal handler.  Therefore, it
 583      * should not do anything that is not signal-safe (such as logging). */
 584     int (*update_flags)(struct netdev *netdev, enum netdev_flags off,
 585                         enum netdev_flags on, enum netdev_flags *old_flags);
 586
 587     /* Returns a sequence number which indicates changes in one of 'netdev''s
 588      * properties.  The returned sequence number must be nonzero so that
 589      * callers have a value which they may use as a reset when tracking
 590      * 'netdev'.
 591      *
 592      * Minimally, the returned sequence number is required to change whenever
 593      * 'netdev''s flags, features, ethernet address, or carrier changes.  The
 594      * returned sequence number is allowed to change even when 'netdev' doesn't
 595      * change, although implementations should try to avoid this. */
 596     unsigned int (*change_seq)(const struct netdev *netdev);
 597 };
 598
 599 int netdev_register_provider(const struct netdev_class *);
 600 int netdev_unregister_provider(const char *type);
 601 const struct netdev_class *netdev_lookup_provider(const char *type);
 602
 603 extern const struct netdev_class netdev_linux_class;
 604 extern const struct netdev_class netdev_internal_class;
 605 extern const struct netdev_class netdev_tap_class;
 606 #ifdef __FreeBSD__
 607 extern const struct netdev_class netdev_bsd_class;
 608 #endif
 609
 610 #ifdef  __cplusplus
 611 }
 612 #endif
 613
 614 #endif /* netdev.h */