2 * Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
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:
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
17 #ifndef NETDEV_PROVIDER_H
18 #define NETDEV_PROVIDER_H 1
20 /* Generic interface to network devices. */
31 /* A network device (e.g. an Ethernet device).
33 * Network device implementations may read these members but should not modify
36 /* The following do not change during the lifetime of a struct netdev. */
37 char *name; /* Name of network device. */
38 const struct netdev_class *netdev_class; /* Functions to control
41 /* The following are protected by 'netdev_mutex' (internal to netdev.c). */
42 int ref_cnt; /* Times this devices was opened. */
43 struct shash_node *node; /* Pointer to element in global map. */
44 struct list saved_flags_list; /* Contains "struct netdev_saved_flags". */
47 const char *netdev_get_type(const struct netdev *);
48 const struct netdev_class *netdev_get_class(const struct netdev *);
49 const char *netdev_get_name(const struct netdev *);
50 struct netdev *netdev_from_name(const char *name);
51 void netdev_get_devices(const struct netdev_class *,
52 struct shash *device_list);
54 /* A data structure for capturing packets received by a network device.
56 * Network device implementations may read these members but should not modify
59 * None of these members change during the lifetime of a struct netdev_rx. */
61 struct netdev *netdev; /* Owns a reference to the netdev. */
64 struct netdev *netdev_rx_get_netdev(const struct netdev_rx *);
66 /* Network device class structure, to be defined by each implementation of a
69 * These functions return 0 if successful or a positive errno value on failure,
70 * except where otherwise noted.
76 * These functions work primarily with two different kinds of data structures:
78 * - "struct netdev", which represents a network device.
80 * - "struct netdev_rx", which represents a handle for capturing packets
81 * received on a network device
83 * Each of these data structures contains all of the implementation-independent
84 * generic state for the respective concept, called the "base" state. None of
85 * them contains any extra space for implementations to use. Instead, each
86 * implementation is expected to declare its own data structure that contains
87 * an instance of the generic data structure plus additional
88 * implementation-specific members, called the "derived" state. The
89 * implementation can use casts or (preferably) the CONTAINER_OF macro to
90 * obtain access to derived state given only a pointer to the embedded generic
97 * Four stylized functions accompany each of these data structures:
99 * "alloc" "construct" "destruct" "dealloc"
100 * ------------ ---------------- --------------- --------------
101 * netdev ->alloc ->construct ->destruct ->dealloc
102 * netdev_rx ->rx_alloc ->rx_construct ->rx_destruct ->rx_dealloc
104 * Any instance of a given data structure goes through the following life
107 * 1. The client calls the "alloc" function to obtain raw memory. If "alloc"
108 * fails, skip all the other steps.
110 * 2. The client initializes all of the data structure's base state. If this
111 * fails, skip to step 7.
113 * 3. The client calls the "construct" function. The implementation
114 * initializes derived state. It may refer to the already-initialized
115 * base state. If "construct" fails, skip to step 6.
117 * 4. The data structure is now initialized and in use.
119 * 5. When the data structure is no longer needed, the client calls the
120 * "destruct" function. The implementation uninitializes derived state.
121 * The base state has not been uninitialized yet, so the implementation
122 * may still refer to it.
124 * 6. The client uninitializes all of the data structure's base state.
126 * 7. The client calls the "dealloc" to free the raw memory. The
127 * implementation must not refer to base or derived state in the data
128 * structure, because it has already been uninitialized.
130 * Each "alloc" function allocates and returns a new instance of the respective
131 * data structure. The "alloc" function is not given any information about the
132 * use of the new data structure, so it cannot perform much initialization.
133 * Its purpose is just to ensure that the new data structure has enough room
134 * for base and derived state. It may return a null pointer if memory is not
135 * available, in which case none of the other functions is called.
137 * Each "construct" function initializes derived state in its respective data
138 * structure. When "construct" is called, all of the base state has already
139 * been initialized, so the "construct" function may refer to it. The
140 * "construct" function is allowed to fail, in which case the client calls the
141 * "dealloc" function (but not the "destruct" function).
143 * Each "destruct" function uninitializes and frees derived state in its
144 * respective data structure. When "destruct" is called, the base state has
145 * not yet been uninitialized, so the "destruct" function may refer to it. The
146 * "destruct" function is not allowed to fail.
148 * Each "dealloc" function frees raw memory that was allocated by the the
149 * "alloc" function. The memory's base and derived members might not have ever
150 * been initialized (but if "construct" returned successfully, then it has been
151 * "destruct"ed already). The "dealloc" function is not allowed to fail. */
152 struct netdev_class {
153 /* Type of netdevs in this class, e.g. "system", "tap", "gre", etc.
155 * One of the providers should supply a "system" type, since this is
156 * the type assumed if no type is specified when opening a netdev.
157 * The "system" type corresponds to an existing network device on
161 /* ## ------------------- ## */
162 /* ## Top-Level Functions ## */
163 /* ## ------------------- ## */
165 /* Called when the netdev provider is registered, typically at program
166 * startup. Returning an error from this function will prevent any network
167 * device in this class from being opened.
169 * This function may be set to null if a network device class needs no
170 * initialization at registration time. */
173 /* Performs periodic work needed by netdevs of this class. May be null if
174 * no periodic work is necessary. */
177 /* Arranges for poll_block() to wake up if the "run" member function needs
178 * to be called. Implementations are additionally required to wake
179 * whenever something changes in any of its netdevs which would cause their
180 * ->change_seq() function to change its result. May be null if nothing is
184 /* ## ---------------- ## */
185 /* ## netdev Functions ## */
186 /* ## ---------------- ## */
188 /* Life-cycle functions for a netdev. See the large comment above on
189 * struct netdev_class. */
190 struct netdev *(*alloc)(void);
191 int (*construct)(struct netdev *);
192 void (*destruct)(struct netdev *);
193 void (*dealloc)(struct netdev *);
195 /* Fetches the device 'netdev''s configuration, storing it in 'args'.
196 * The caller owns 'args' and pre-initializes it to an empty smap.
198 * If this netdev class does not have any configuration options, this may
199 * be a null pointer. */
200 int (*get_config)(const struct netdev *netdev, struct smap *args);
202 /* Changes the device 'netdev''s configuration to 'args'.
204 * If this netdev class does not support configuration, this may be a null
206 int (*set_config)(struct netdev *netdev, const struct smap *args);
208 /* Returns the tunnel configuration of 'netdev'. If 'netdev' is
209 * not a tunnel, returns null.
211 * If this function would always return null, it may be null instead. */
212 const struct netdev_tunnel_config *
213 (*get_tunnel_config)(const struct netdev *netdev);
215 /* Sends the 'size'-byte packet in 'buffer' on 'netdev'. Returns 0 if
216 * successful, otherwise a positive errno value. Returns EAGAIN without
217 * blocking if the packet cannot be queued immediately. Returns EMSGSIZE
218 * if a partial packet was transmitted or if the packet is too big or too
219 * small to transmit on the device.
221 * The caller retains ownership of 'buffer' in all cases.
223 * The network device is expected to maintain a packet transmission queue,
224 * so that the caller does not ordinarily have to do additional queuing of
227 * May return EOPNOTSUPP if a network device does not implement packet
228 * transmission through this interface. This function may be set to null
229 * if it would always return EOPNOTSUPP anyhow. (This will prevent the
230 * network device from being usefully used by the netdev-based "userspace
231 * datapath". It will also prevent the OVS implementation of bonding from
232 * working properly over 'netdev'.) */
233 int (*send)(struct netdev *netdev, const void *buffer, size_t size);
235 /* Registers with the poll loop to wake up from the next call to
236 * poll_block() when the packet transmission queue for 'netdev' has
237 * sufficient room to transmit a packet with netdev_send().
239 * The network device is expected to maintain a packet transmission queue,
240 * so that the caller does not ordinarily have to do additional queuing of
241 * packets. Thus, this function is unlikely to ever be useful.
243 * May be null if not needed, such as for a network device that does not
244 * implement packet transmission through the 'send' member function. */
245 void (*send_wait)(struct netdev *netdev);
247 /* Sets 'netdev''s Ethernet address to 'mac' */
248 int (*set_etheraddr)(struct netdev *netdev, const uint8_t mac[6]);
250 /* Retrieves 'netdev''s Ethernet address into 'mac'.
252 * This address will be advertised as 'netdev''s MAC address through the
253 * OpenFlow protocol, among other uses. */
254 int (*get_etheraddr)(const struct netdev *netdev, uint8_t mac[6]);
256 /* Retrieves 'netdev''s MTU into '*mtup'.
258 * The MTU is the maximum size of transmitted (and received) packets, in
259 * bytes, not including the hardware header; thus, this is typically 1500
260 * bytes for Ethernet devices.
262 * If 'netdev' does not have an MTU (e.g. as some tunnels do not), then
263 * this function should return EOPNOTSUPP. This function may be set to
264 * null if it would always return EOPNOTSUPP. */
265 int (*get_mtu)(const struct netdev *netdev, int *mtup);
267 /* Sets 'netdev''s MTU to 'mtu'.
269 * If 'netdev' does not have an MTU (e.g. as some tunnels do not), then
270 * this function should return EOPNOTSUPP. This function may be set to
271 * null if it would always return EOPNOTSUPP. */
272 int (*set_mtu)(const struct netdev *netdev, int mtu);
274 /* Returns the ifindex of 'netdev', if successful, as a positive number.
275 * On failure, returns a negative errno value.
277 * The desired semantics of the ifindex value are a combination of those
278 * specified by POSIX for if_nametoindex() and by SNMP for ifIndex. An
279 * ifindex value should be unique within a host and remain stable at least
280 * until reboot. SNMP says an ifindex "ranges between 1 and the value of
281 * ifNumber" but many systems do not follow this rule anyhow.
283 * This function may be set to null if it would always return -EOPNOTSUPP.
285 int (*get_ifindex)(const struct netdev *netdev);
287 /* Sets 'carrier' to true if carrier is active (link light is on) on
290 * May be null if device does not provide carrier status (will be always
291 * up as long as device is up).
293 int (*get_carrier)(const struct netdev *netdev, bool *carrier);
295 /* Returns the number of times 'netdev''s carrier has changed since being
298 * If null, callers will assume the number of carrier resets is zero. */
299 long long int (*get_carrier_resets)(const struct netdev *netdev);
301 /* Forces ->get_carrier() to poll 'netdev''s MII registers for link status
302 * instead of checking 'netdev''s carrier. 'netdev''s MII registers will
303 * be polled once ever 'interval' milliseconds. If 'netdev' does not
304 * support MII, another method may be used as a fallback. If 'interval' is
305 * less than or equal to zero, reverts ->get_carrier() to its normal
308 * Most network devices won't support this feature and will set this
309 * function pointer to NULL, which is equivalent to returning EOPNOTSUPP.
311 int (*set_miimon_interval)(struct netdev *netdev, long long int interval);
313 /* Retrieves current device stats for 'netdev' into 'stats'.
315 * A network device that supports some statistics but not others, it should
316 * set the values of the unsupported statistics to all-1-bits
318 int (*get_stats)(const struct netdev *netdev, struct netdev_stats *);
320 /* Sets the device stats for 'netdev' to 'stats'.
322 * Most network devices won't support this feature and will set this
323 * function pointer to NULL, which is equivalent to returning EOPNOTSUPP.
325 * Some network devices might only allow setting their stats to 0. */
326 int (*set_stats)(struct netdev *netdev, const struct netdev_stats *);
328 /* Stores the features supported by 'netdev' into each of '*current',
329 * '*advertised', '*supported', and '*peer'. Each value is a bitmap of
332 * This function may be set to null if it would always return EOPNOTSUPP.
334 int (*get_features)(const struct netdev *netdev,
335 enum netdev_features *current,
336 enum netdev_features *advertised,
337 enum netdev_features *supported,
338 enum netdev_features *peer);
340 /* Set the features advertised by 'netdev' to 'advertise', which is a
341 * set of NETDEV_F_* bits.
343 * This function may be set to null for a network device that does not
344 * support configuring advertisements. */
345 int (*set_advertisements)(struct netdev *netdev,
346 enum netdev_features advertise);
348 /* Attempts to set input rate limiting (policing) policy, such that up to
349 * 'kbits_rate' kbps of traffic is accepted, with a maximum accumulative
350 * burst size of 'kbits' kb.
352 * This function may be set to null if policing is not supported. */
353 int (*set_policing)(struct netdev *netdev, unsigned int kbits_rate,
354 unsigned int kbits_burst);
356 /* Adds to 'types' all of the forms of QoS supported by 'netdev', or leaves
357 * it empty if 'netdev' does not support QoS. Any names added to 'types'
358 * should be documented as valid for the "type" column in the "QoS" table
359 * in vswitchd/vswitch.xml (which is built as ovs-vswitchd.conf.db(8)).
361 * Every network device must support disabling QoS with a type of "", but
362 * this function must not add "" to 'types'.
364 * The caller is responsible for initializing 'types' (e.g. with
365 * sset_init()) before calling this function. The caller retains ownership
368 * May be NULL if 'netdev' does not support QoS at all. */
369 int (*get_qos_types)(const struct netdev *netdev, struct sset *types);
371 /* Queries 'netdev' for its capabilities regarding the specified 'type' of
372 * QoS. On success, initializes 'caps' with the QoS capabilities.
374 * Should return EOPNOTSUPP if 'netdev' does not support 'type'. May be
375 * NULL if 'netdev' does not support QoS at all. */
376 int (*get_qos_capabilities)(const struct netdev *netdev,
378 struct netdev_qos_capabilities *caps);
380 /* Queries 'netdev' about its currently configured form of QoS. If
381 * successful, stores the name of the current form of QoS into '*typep'
382 * and any details of configuration as string key-value pairs in
385 * A '*typep' of "" indicates that QoS is currently disabled on 'netdev'.
387 * The caller initializes 'details' before calling this function. The
388 * caller takes ownership of the string key-values pairs added to
391 * The netdev retains ownership of '*typep'.
393 * '*typep' will be one of the types returned by netdev_get_qos_types() for
394 * 'netdev'. The contents of 'details' should be documented as valid for
395 * '*typep' in the "other_config" column in the "QoS" table in
396 * vswitchd/vswitch.xml (which is built as ovs-vswitchd.conf.db(8)).
398 * May be NULL if 'netdev' does not support QoS at all. */
399 int (*get_qos)(const struct netdev *netdev,
400 const char **typep, struct smap *details);
402 /* Attempts to reconfigure QoS on 'netdev', changing the form of QoS to
403 * 'type' with details of configuration from 'details'.
405 * On error, the previous QoS configuration is retained.
407 * When this function changes the type of QoS (not just 'details'), this
408 * also resets all queue configuration for 'netdev' to their defaults
409 * (which depend on the specific type of QoS). Otherwise, the queue
410 * configuration for 'netdev' is unchanged.
412 * 'type' should be "" (to disable QoS) or one of the types returned by
413 * netdev_get_qos_types() for 'netdev'. The contents of 'details' should
414 * be documented as valid for the given 'type' in the "other_config" column
415 * in the "QoS" table in vswitchd/vswitch.xml (which is built as
416 * ovs-vswitchd.conf.db(8)).
418 * May be NULL if 'netdev' does not support QoS at all. */
419 int (*set_qos)(struct netdev *netdev,
420 const char *type, const struct smap *details);
422 /* Queries 'netdev' for information about the queue numbered 'queue_id'.
423 * If successful, adds that information as string key-value pairs to
424 * 'details'. Returns 0 if successful, otherwise a positive errno value.
426 * Should return EINVAL if 'queue_id' is greater than or equal to the
427 * number of supported queues (as reported in the 'n_queues' member of
428 * struct netdev_qos_capabilities by 'get_qos_capabilities').
430 * The caller initializes 'details' before calling this function. The
431 * caller takes ownership of the string key-values pairs added to
434 * The returned contents of 'details' should be documented as valid for the
435 * given 'type' in the "other_config" column in the "Queue" table in
436 * vswitchd/vswitch.xml (which is built as ovs-vswitchd.conf.db(8)).
438 int (*get_queue)(const struct netdev *netdev,
439 unsigned int queue_id, struct smap *details);
441 /* Configures the queue numbered 'queue_id' on 'netdev' with the key-value
442 * string pairs in 'details'. The contents of 'details' should be
443 * documented as valid for the given 'type' in the "other_config" column in
444 * the "Queue" table in vswitchd/vswitch.xml (which is built as
445 * ovs-vswitchd.conf.db(8)). Returns 0 if successful, otherwise a positive
446 * errno value. On failure, the given queue's configuration should be
449 * Should return EINVAL if 'queue_id' is greater than or equal to the
450 * number of supported queues (as reported in the 'n_queues' member of
451 * struct netdev_qos_capabilities by 'get_qos_capabilities'), or if
452 * 'details' is invalid for the type of queue.
454 * This function does not modify 'details', and the caller retains
457 * May be NULL if 'netdev' does not support QoS at all. */
458 int (*set_queue)(struct netdev *netdev,
459 unsigned int queue_id, const struct smap *details);
461 /* Attempts to delete the queue numbered 'queue_id' from 'netdev'.
463 * Should return EINVAL if 'queue_id' is greater than or equal to the
464 * number of supported queues (as reported in the 'n_queues' member of
465 * struct netdev_qos_capabilities by 'get_qos_capabilities'). Should
466 * return EOPNOTSUPP if 'queue_id' is valid but may not be deleted (e.g. if
467 * 'netdev' has a fixed set of queues with the current QoS mode).
469 * May be NULL if 'netdev' does not support QoS at all, or if all of its
470 * QoS modes have fixed sets of queues. */
471 int (*delete_queue)(struct netdev *netdev, unsigned int queue_id);
473 /* Obtains statistics about 'queue_id' on 'netdev'. Fills 'stats' with the
474 * queue's statistics. May set individual members of 'stats' to all-1-bits
475 * if the statistic is unavailable.
477 * May be NULL if 'netdev' does not support QoS at all. */
478 int (*get_queue_stats)(const struct netdev *netdev, unsigned int queue_id,
479 struct netdev_queue_stats *stats);
481 /* Attempts to begin dumping the queues in 'netdev'. On success, returns 0
482 * and initializes '*statep' with any data needed for iteration. On
483 * failure, returns a positive errno value.
485 * May be NULL if 'netdev' does not support QoS at all. */
486 int (*queue_dump_start)(const struct netdev *netdev, void **statep);
488 /* Attempts to retrieve another queue from 'netdev' for 'state', which was
489 * initialized by a successful call to the 'queue_dump_start' function for
490 * 'netdev'. On success, stores a queue ID into '*queue_id' and fills
491 * 'details' with the configuration of the queue with that ID. Returns EOF
492 * if the last queue has been dumped, or a positive errno value on error.
493 * This function will not be called again once it returns nonzero once for
494 * a given iteration (but the 'queue_dump_done' function will be called
497 * The caller initializes and clears 'details' before calling this
498 * function. The caller takes ownership of the string key-values pairs
499 * added to 'details'.
501 * The returned contents of 'details' should be documented as valid for the
502 * given 'type' in the "other_config" column in the "Queue" table in
503 * vswitchd/vswitch.xml (which is built as ovs-vswitchd.conf.db(8)).
505 * May be NULL if 'netdev' does not support QoS at all. */
506 int (*queue_dump_next)(const struct netdev *netdev, void *state,
507 unsigned int *queue_id, struct smap *details);
509 /* Releases resources from 'netdev' for 'state', which was initialized by a
510 * successful call to the 'queue_dump_start' function for 'netdev'.
512 * May be NULL if 'netdev' does not support QoS at all. */
513 int (*queue_dump_done)(const struct netdev *netdev, void *state);
515 /* Iterates over all of 'netdev''s queues, calling 'cb' with the queue's
516 * ID, its statistics, and the 'aux' specified by the caller. The order of
517 * iteration is unspecified, but (when successful) each queue must be
518 * visited exactly once.
520 * 'cb' will not modify or free the statistics passed in. */
521 int (*dump_queue_stats)(const struct netdev *netdev,
522 void (*cb)(unsigned int queue_id,
523 struct netdev_queue_stats *,
527 /* If 'netdev' has an assigned IPv4 address, sets '*address' to that
528 * address and '*netmask' to the associated netmask.
530 * The following error values have well-defined meanings:
532 * - EADDRNOTAVAIL: 'netdev' has no assigned IPv4 address.
534 * - EOPNOTSUPP: No IPv4 network stack attached to 'netdev'.
536 * This function may be set to null if it would always return EOPNOTSUPP
538 int (*get_in4)(const struct netdev *netdev, struct in_addr *address,
539 struct in_addr *netmask);
541 /* Assigns 'addr' as 'netdev''s IPv4 address and 'mask' as its netmask. If
542 * 'addr' is INADDR_ANY, 'netdev''s IPv4 address is cleared.
544 * This function may be set to null if it would always return EOPNOTSUPP
546 int (*set_in4)(struct netdev *netdev, struct in_addr addr,
547 struct in_addr mask);
549 /* If 'netdev' has an assigned IPv6 address, sets '*in6' to that address.
551 * The following error values have well-defined meanings:
553 * - EADDRNOTAVAIL: 'netdev' has no assigned IPv6 address.
555 * - EOPNOTSUPP: No IPv6 network stack attached to 'netdev'.
557 * This function may be set to null if it would always return EOPNOTSUPP
559 int (*get_in6)(const struct netdev *netdev, struct in6_addr *in6);
561 /* Adds 'router' as a default IP gateway for the TCP/IP stack that
562 * corresponds to 'netdev'.
564 * This function may be set to null if it would always return EOPNOTSUPP
566 int (*add_router)(struct netdev *netdev, struct in_addr router);
568 /* Looks up the next hop for 'host'. If successful, stores the next hop
569 * gateway's address (0 if 'host' is on a directly connected network) in
570 * '*next_hop' and a copy of the name of the device to reach 'host' in
571 * '*netdev_name', and returns 0. The caller is responsible for freeing
572 * '*netdev_name' (by calling free()).
574 * This function may be set to null if it would always return EOPNOTSUPP
576 int (*get_next_hop)(const struct in_addr *host, struct in_addr *next_hop,
579 /* Retrieves driver information of the device.
581 * Populates 'smap' with key-value pairs representing the status of the
582 * device. 'smap' is a set of key-value string pairs representing netdev
583 * type specific information. For more information see
584 * ovs-vswitchd.conf.db(5).
586 * The caller is responsible for destroying 'smap' and its data.
588 * This function may be set to null if it would always return EOPNOTSUPP
590 int (*get_status)(const struct netdev *netdev, struct smap *smap);
592 /* Looks up the ARP table entry for 'ip' on 'netdev' and stores the
593 * corresponding MAC address in 'mac'. A return value of ENXIO, in
594 * particular, indicates that there is no ARP table entry for 'ip' on
597 * This function may be set to null if it would always return EOPNOTSUPP
599 int (*arp_lookup)(const struct netdev *netdev, ovs_be32 ip,
602 /* Retrieves the current set of flags on 'netdev' into '*old_flags'. Then,
603 * turns off the flags that are set to 1 in 'off' and turns on the flags
604 * that are set to 1 in 'on'. (No bit will be set to 1 in both 'off' and
605 * 'on'; that is, off & on == 0.)
607 * This function may be invoked from a signal handler. Therefore, it
608 * should not do anything that is not signal-safe (such as logging). */
609 int (*update_flags)(struct netdev *netdev, enum netdev_flags off,
610 enum netdev_flags on, enum netdev_flags *old_flags);
612 /* Returns a sequence number which indicates changes in one of 'netdev''s
613 * properties. The returned sequence number must be nonzero so that
614 * callers have a value which they may use as a reset when tracking
617 * Minimally, the returned sequence number is required to change whenever
618 * 'netdev''s flags, features, ethernet address, or carrier changes. The
619 * returned sequence number is allowed to change even when 'netdev' doesn't
620 * change, although implementations should try to avoid this. */
621 unsigned int (*change_seq)(const struct netdev *netdev);
623 /* ## ------------------- ## */
624 /* ## netdev_rx Functions ## */
625 /* ## ------------------- ## */
627 /* If a particular netdev class does not support receiving packets, all these
628 * function pointers must be NULL. */
630 /* Life-cycle functions for a netdev_rx. See the large comment above on
631 * struct netdev_class. */
632 struct netdev_rx *(*rx_alloc)(void);
633 int (*rx_construct)(struct netdev_rx *);
634 void (*rx_destruct)(struct netdev_rx *);
635 void (*rx_dealloc)(struct netdev_rx *);
637 /* Attempts to receive a packet from 'rx' into the 'size' bytes in
638 * 'buffer'. If successful, returns the number of bytes in the received
639 * packet, otherwise a negative errno value. Returns -EAGAIN immediately
640 * if no packet is ready to be received.
642 * Must return -EMSGSIZE, and discard the packet, if the received packet
643 * is longer than 'size' bytes.
645 * Specify NULL if this */
646 int (*rx_recv)(struct netdev_rx *rx, void *buffer, size_t size);
648 /* Registers with the poll loop to wake up from the next call to
649 * poll_block() when a packet is ready to be received with netdev_rx_recv()
651 void (*rx_wait)(struct netdev_rx *rx);
653 /* Discards all packets waiting to be received from 'rx'. */
654 int (*rx_drain)(struct netdev_rx *rx);
657 int netdev_register_provider(const struct netdev_class *);
658 int netdev_unregister_provider(const char *type);
660 extern const struct netdev_class netdev_linux_class;
661 extern const struct netdev_class netdev_internal_class;
662 extern const struct netdev_class netdev_tap_class;
663 #if defined(__FreeBSD__) || defined(__NetBSD__)
664 extern const struct netdev_class netdev_bsd_class;
667 extern const struct netdev_class netdev_tunnel_class;
668 extern const struct netdev_class netdev_pltap_class;
674 #endif /* netdev.h */