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