lib/netdev-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 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
  28 #ifdef  __cplusplus
  29 extern "C" {
  30 #endif
  31
  32 struct arg {
  33     char *key;
  34     char *value;
  35 };
  36
  37 /* A network device (e.g. an Ethernet device).
  38  *
  39  * This structure should be treated as opaque by network device
  40  * implementations. */
  41 struct netdev_dev {
  42     char *name;                         /* Name of network device. */
  43     const struct netdev_class *netdev_class; /* Functions to control
  44                                                 this device. */
  45     int ref_cnt;                        /* Times this devices was opened. */
  46     struct shash_node *node;            /* Pointer to element in global map. */
  47     struct arg *args;                   /* Argument list from last config. */
  48     int n_args;                         /* Number of arguments in 'args'. */
  49 };
  50
  51 void netdev_dev_init(struct netdev_dev *, const char *name,
  52                      const struct netdev_class *);
  53 void netdev_dev_uninit(struct netdev_dev *, bool destroy);
  54 const char *netdev_dev_get_type(const struct netdev_dev *);
  55 const struct netdev_class *netdev_dev_get_class(const struct netdev_dev *);
  56 const char *netdev_dev_get_name(const struct netdev_dev *);
  57 struct netdev_dev *netdev_dev_from_name(const char *name);
  58 void netdev_dev_get_devices(const struct netdev_class *,
  59                             struct shash *device_list);
  60
  61 static inline void netdev_dev_assert_class(const struct netdev_dev *netdev_dev,
  62                                            const struct netdev_class *class_)
  63 {
  64     assert(netdev_dev->netdev_class == class_);
  65 }
  66
  67 /* A instance of an open network device.
  68  *
  69  * This structure should be treated as opaque by network device
  70  * implementations. */
  71 struct netdev {
  72     struct netdev_dev *netdev_dev;   /* Parent netdev_dev. */
  73     struct list node;                /* Element in global list. */
  74
  75     enum netdev_flags save_flags;    /* Initial device flags. */
  76     enum netdev_flags changed_flags; /* Flags that we changed. */
  77 };
  78
  79 void netdev_init(struct netdev *, struct netdev_dev *);
  80 void netdev_uninit(struct netdev *, bool close);
  81 struct netdev_dev *netdev_get_dev(const struct netdev *);
  82
  83 static inline void netdev_assert_class(const struct netdev *netdev,
  84                                        const struct netdev_class *netdev_class)
  85 {
  86     netdev_dev_assert_class(netdev_get_dev(netdev), netdev_class);
  87 }
  88
  89 /* A network device notifier.
  90  *
  91  * Network device implementations should use netdev_notifier_init() to
  92  * initialize this structure, but they may freely read its members after
  93  * initialization. */
  94 struct netdev_notifier {
  95     struct netdev *netdev;
  96     void (*cb)(struct netdev_notifier *);
  97     void *aux;
  98 };
  99 void netdev_notifier_init(struct netdev_notifier *, struct netdev *,
 100                           void (*cb)(struct netdev_notifier *), void *aux);
 101
 102 /* Network device class structure, to be defined by each implementation of a
 103  * network device.
 104  *
 105  * These functions return 0 if successful or a positive errno value on failure,
 106  * except where otherwise noted. */
 107 struct netdev_class {
 108     /* Type of netdevs in this class, e.g. "system", "tap", "gre", etc.
 109      *
 110      * One of the providers should supply a "system" type, since this is
 111      * the type assumed if no type is specified when opening a netdev.
 112      * The "system" type corresponds to an existing network device on
 113      * the system. */
 114     const char *type;
 115
 116     /* Called when the netdev provider is registered, typically at program
 117      * startup.  Returning an error from this function will prevent any network
 118      * device in this class from being opened.
 119      *
 120      * This function may be set to null if a network device class needs no
 121      * initialization at registration time. */
 122     int (*init)(void);
 123
 124     /* Performs periodic work needed by netdevs of this class.  May be null if
 125      * no periodic work is necessary. */
 126     void (*run)(void);
 127
 128     /* Arranges for poll_block() to wake up if the "run" member function needs
 129      * to be called.  May be null if nothing is needed here. */
 130     void (*wait)(void);
 131
 132     /* Attempts to create a network device of 'type' with 'name'.
 133      * 'type' corresponds to the 'type' field used in the netdev_class
 134      * structure. On success sets 'netdev_devp' to the newly created device. */
 135     int (*create)(const char *name, const char *type, const struct shash *args,
 136                   struct netdev_dev **netdev_devp);
 137
 138     /* Destroys 'netdev_dev'.
 139      *
 140      * Netdev devices maintain a reference count that is incremented on
 141      * netdev_open() and decremented on netdev_close().  If 'netdev_dev'
 142      * has a non-zero reference count, then this function will not be
 143      * called. */
 144     void (*destroy)(struct netdev_dev *netdev_dev);
 145
 146     /* Reconfigures the device 'netdev_dev' with 'args'.
 147      *
 148      * If this netdev class does not support reconfiguring a netdev
 149      * device, this may be a null pointer.
 150      */
 151     int (*reconfigure)(struct netdev_dev *netdev_dev, const struct shash *args);
 152
 153     /* Attempts to open a network device.  On success, sets 'netdevp'
 154      * to the new network device.
 155      *
 156      * 'ethertype' may be a 16-bit Ethernet protocol value in host byte order
 157      * to capture frames of that type received on the device.  It may also be
 158      * one of the 'enum netdev_pseudo_ethertype' values to receive frames in
 159      * one of those categories. */
 160     int (*open)(struct netdev_dev *netdev_dev, int ethertype,
 161                 struct netdev **netdevp);
 162
 163     /* Closes 'netdev'. */
 164     void (*close)(struct netdev *netdev);
 165
 166     /* Enumerates the names of all network devices of this class.
 167      *
 168      * The caller has already initialized 'all_names' and might already have
 169      * added some names to it.  This function should not disturb any existing
 170      * names in 'all_names'.
 171      *
 172      * If this netdev class does not support enumeration, this may be a null
 173      * pointer. */
 174     int (*enumerate)(struct svec *all_names);
 175
 176     /* Attempts to receive a packet from 'netdev' into the 'size' bytes in
 177      * 'buffer'.  If successful, returns the number of bytes in the received
 178      * packet, otherwise a negative errno value.  Returns -EAGAIN immediately
 179      * if no packet is ready to be received.
 180      *
 181      * May return -EOPNOTSUPP if a network device does not implement packet
 182      * reception through this interface.  This function may be set to null if
 183      * it would always return -EOPNOTSUPP anyhow.  (This will disable the OVS
 184      * integrated DHCP client and OpenFlow controller discovery, and prevent
 185      * the network device from being usefully used by the netdev-based
 186      * "userspace datapath".) */
 187     int (*recv)(struct netdev *netdev, void *buffer, size_t size);
 188
 189     /* Registers with the poll loop to wake up from the next call to
 190      * poll_block() when a packet is ready to be received with netdev_recv() on
 191      * 'netdev'.
 192      *
 193      * May be null if not needed, such as for a network device that does not
 194      * implement packet reception through the 'recv' member function. */
 195     void (*recv_wait)(struct netdev *netdev);
 196
 197     /* Discards all packets waiting to be received from 'netdev'.
 198      *
 199      * May be null if not needed, such as for a network device that does not
 200      * implement packet reception through the 'recv' member function. */
 201     int (*drain)(struct netdev *netdev);
 202
 203     /* Sends the 'size'-byte packet in 'buffer' on 'netdev'.  Returns 0 if
 204      * successful, otherwise a positive errno value.  Returns EAGAIN without
 205      * blocking if the packet cannot be queued immediately.  Returns EMSGSIZE
 206      * if a partial packet was transmitted or if the packet is too big or too
 207      * small to transmit on the device.
 208      *
 209      * The caller retains ownership of 'buffer' in all cases.
 210      *
 211      * The network device is expected to maintain a packet transmission queue,
 212      * so that the caller does not ordinarily have to do additional queuing of
 213      * packets.
 214      *
 215      * May return EOPNOTSUPP if a network device does not implement packet
 216      * transmission through this interface.  This function may be set to null
 217      * if it would always return EOPNOTSUPP anyhow.  (This will disable the OVS
 218      * integrated DHCP client and OpenFlow controller discovery, and prevent
 219      * the network device from being usefully used by the netdev-based
 220      * "userspace datapath".) */
 221     int (*send)(struct netdev *netdev, const void *buffer, size_t size);
 222
 223     /* Registers with the poll loop to wake up from the next call to
 224      * poll_block() when the packet transmission queue for 'netdev' has
 225      * sufficient room to transmit a packet with netdev_send().
 226      *
 227      * The network device is expected to maintain a packet transmission queue,
 228      * so that the caller does not ordinarily have to do additional queuing of
 229      * packets.  Thus, this function is unlikely to ever be useful.
 230      *
 231      * May be null if not needed, such as for a network device that does not
 232      * implement packet transmission through the 'send' member function. */
 233     void (*send_wait)(struct netdev *netdev);
 234
 235     /* Sets 'netdev''s Ethernet address to 'mac' */
 236     int (*set_etheraddr)(struct netdev *netdev, const uint8_t mac[6]);
 237
 238     /* Retrieves 'netdev''s Ethernet address into 'mac'. */
 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     int (*get_mtu)(const struct netdev *netdev, int *mtup);
 247
 248     /* Returns the ifindex of 'netdev', if successful, as a positive number.
 249      * On failure, returns a negative errno value.
 250      *
 251      * The desired semantics of the ifindex value are a combination of those
 252      * specified by POSIX for if_nametoindex() and by SNMP for ifIndex.  An
 253      * ifindex value should be unique within a host and remain stable at least
 254      * until reboot.  SNMP says an ifindex "ranges between 1 and the value of
 255      * ifNumber" but many systems do not follow this rule anyhow. */
 256     int (*get_ifindex)(const struct netdev *netdev);
 257
 258     /* Sets 'carrier' to true if carrier is active (link light is on) on
 259      * 'netdev'. */
 260     int (*get_carrier)(const struct netdev *netdev, bool *carrier);
 261
 262     /* Retrieves current device stats for 'netdev' into 'stats'.
 263      *
 264      * A network device that supports some statistics but not others, it should
 265      * set the values of the unsupported statistics to all-1-bits
 266      * (UINT64_MAX). */
 267     int (*get_stats)(const struct netdev *netdev, struct netdev_stats *);
 268
 269     /* Stores the features supported by 'netdev' into each of '*current',
 270      * '*advertised', '*supported', and '*peer'.  Each value is a bitmap of
 271      * "enum ofp_port_features" bits, in host byte order. */
 272     int (*get_features)(struct netdev *netdev,
 273                         uint32_t *current, uint32_t *advertised,
 274                         uint32_t *supported, uint32_t *peer);
 275
 276     /* Set the features advertised by 'netdev' to 'advertise', which is a
 277      * bitmap of "enum ofp_port_features" bits, in host byte order.
 278      *
 279      * This function may be set to null for a network device that does not
 280      * support configuring advertisements. */
 281     int (*set_advertisements)(struct netdev *netdev, uint32_t advertise);
 282
 283     /* If 'netdev' is a VLAN network device (e.g. one created with vconfig(8)),
 284      * sets '*vlan_vid' to the VLAN VID associated with that device and returns
 285      * 0.
 286      *
 287      * Returns ENOENT if 'netdev' is a network device that is not a
 288      * VLAN device.
 289      *
 290      * This function should be set to null if it doesn't make any sense for
 291      * your network device (it probably doesn't). */
 292     int (*get_vlan_vid)(const struct netdev *netdev, int *vlan_vid);
 293
 294     /* Attempts to set input rate limiting (policing) policy, such that up to
 295      * 'kbits_rate' kbps of traffic is accepted, with a maximum accumulative
 296      * burst size of 'kbits' kb.
 297      *
 298      * This function may be set to null if policing is not supported. */
 299     int (*set_policing)(struct netdev *netdev, unsigned int kbits_rate,
 300                         unsigned int kbits_burst);
 301
 302     /* If 'netdev' has an assigned IPv4 address, sets '*address' to that
 303      * address and '*netmask' to the associated netmask.
 304      *
 305      * The following error values have well-defined meanings:
 306      *
 307      *   - EADDRNOTAVAIL: 'netdev' has no assigned IPv4 address.
 308      *
 309      *   - EOPNOTSUPP: No IPv4 network stack attached to 'netdev'.
 310      *
 311      * This function may be set to null if it would always return EOPNOTSUPP
 312      * anyhow. */
 313     int (*get_in4)(const struct netdev *netdev, struct in_addr *address,
 314                    struct in_addr *netmask);
 315
 316     /* Assigns 'addr' as 'netdev''s IPv4 address and 'mask' as its netmask.  If
 317      * 'addr' is INADDR_ANY, 'netdev''s IPv4 address is cleared.
 318      *
 319      * This function may be set to null if it would always return EOPNOTSUPP
 320      * anyhow. */
 321     int (*set_in4)(struct netdev *netdev, struct in_addr addr,
 322                    struct in_addr mask);
 323
 324     /* If 'netdev' has an assigned IPv6 address, sets '*in6' to that address.
 325      *
 326      * The following error values have well-defined meanings:
 327      *
 328      *   - EADDRNOTAVAIL: 'netdev' has no assigned IPv6 address.
 329      *
 330      *   - EOPNOTSUPP: No IPv6 network stack attached to 'netdev'.
 331      *
 332      * This function may be set to null if it would always return EOPNOTSUPP
 333      * anyhow. */
 334     int (*get_in6)(const struct netdev *netdev, struct in6_addr *in6);
 335
 336     /* Adds 'router' as a default IP gateway for the TCP/IP stack that
 337      * corresponds to 'netdev'.
 338      *
 339      * This function may be set to null if it would always return EOPNOTSUPP
 340      * anyhow. */
 341     int (*add_router)(struct netdev *netdev, struct in_addr router);
 342
 343     /* Looks up the next hop for 'host'.  If succesful, stores the next hop
 344      * gateway's address (0 if 'host' is on a directly connected network) in
 345      * '*next_hop' and a copy of the name of the device to reach 'host' in
 346      * '*netdev_name', and returns 0.  The caller is responsible for freeing
 347      * '*netdev_name' (by calling free()).
 348      *
 349      * This function may be set to null if it would always return EOPNOTSUPP
 350      * anyhow. */
 351     int (*get_next_hop)(const struct in_addr *host, struct in_addr *next_hop,
 352                         char **netdev_name);
 353
 354     /* Looks up the ARP table entry for 'ip' on 'netdev' and stores the
 355      * corresponding MAC address in 'mac'.  A return value of ENXIO, in
 356      * particular, indicates that there is no ARP table entry for 'ip' on
 357      * 'netdev'.
 358      *
 359      * This function may be set to null if it would always return EOPNOTSUPP
 360      * anyhow. */
 361     int (*arp_lookup)(const struct netdev *netdev, uint32_t ip, uint8_t mac[6]);
 362
 363     /* Retrieves the current set of flags on 'netdev' into '*old_flags'.
 364      * Then, turns off the flags that are set to 1 in 'off' and turns on the
 365      * flags that are set to 1 in 'on'.  (No bit will be set to 1 in both 'off'
 366      * and 'on'; that is, off & on == 0.)
 367      *
 368      * This function may be invoked from a signal handler.  Therefore, it
 369      * should not do anything that is not signal-safe (such as logging). */
 370     int (*update_flags)(struct netdev *netdev, enum netdev_flags off,
 371                         enum netdev_flags on, enum netdev_flags *old_flags);
 372
 373     /* Arranges for 'cb' to be called whenever one of the attributes of
 374      * 'netdev' changes and sets '*notifierp' to a newly created
 375      * netdev_notifier that represents this arrangement.  The created notifier
 376      * will have its 'netdev', 'cb', and 'aux' members set to the values of the
 377      * corresponding parameters. */
 378     int (*poll_add)(struct netdev *netdev,
 379                     void (*cb)(struct netdev_notifier *notifier), void *aux,
 380                     struct netdev_notifier **notifierp);
 381
 382     /* Cancels poll notification for 'notifier'. */
 383     void (*poll_remove)(struct netdev_notifier *notifier);
 384 };
 385
 386 extern const struct netdev_class netdev_linux_class;
 387 extern const struct netdev_class netdev_tap_class;
 388 extern const struct netdev_class netdev_gre_class;
 389 extern const struct netdev_class netdev_patch_class;
 390
 391 #ifdef  __cplusplus
 392 }
 393 #endif
 394
 395 #endif /* netdev.h */