lib/netdev-provider.h

   1 /*
   2  * Copyright (c) 2009 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 #include "netdev.h"
  24 #include "list.h"
  25
  26 /* A network device (e.g. an Ethernet device).
  27  *
  28  * This structure should be treated as opaque by network device
  29  * implementations. */
  30 struct netdev {
  31     const struct netdev_class *class;
  32     char *name;                      /* e.g. "eth0" */
  33     enum netdev_flags save_flags;    /* Initial device flags. */
  34     enum netdev_flags changed_flags; /* Flags that we changed. */
  35     struct list node;                /* Element in global list. */
  36 };
  37
  38 void netdev_init(struct netdev *, const char *name,
  39                  const struct netdev_class *);
  40 static inline void netdev_assert_class(const struct netdev *netdev,
  41                                        const struct netdev_class *class)
  42 {
  43     assert(netdev->class == class);
  44 }
  45
  46 /* A network device notifier.
  47  *
  48  * Network device implementations should use netdev_notifier_init() to
  49  * initialize this structure, but they may freely read its members after
  50  * initialization. */
  51 struct netdev_notifier {
  52     struct netdev *netdev;
  53     void (*cb)(struct netdev_notifier *);
  54     void *aux;
  55 };
  56 void netdev_notifier_init(struct netdev_notifier *, struct netdev *,
  57                           void (*cb)(struct netdev_notifier *), void *aux);
  58
  59 /* Network device class structure, to be defined by each implementation of a
  60  * network device.
  61  *
  62  * These functions return 0 if successful or a positive errno value on failure,
  63  * except where otherwise noted. */
  64 struct netdev_class {
  65     /* Prefix for names of netdevs in this class, e.g. "ndunix:".
  66      *
  67      * One netdev class may have the empty string "" as its prefix, in which
  68      * case that netdev class is associated with netdev names that do not
  69      * contain a colon. */
  70     const char *prefix;
  71
  72     /* Class name, for use in error messages. */
  73     const char *name;
  74
  75     /* Called only once, at program startup.  Returning an error from this
  76      * function will prevent any network device in this class from being
  77      * opened.
  78      *
  79      * This function may be set to null if a network device class needs no
  80      * initialization at program startup. */
  81     int (*init)(void);
  82
  83     /* Performs periodic work needed by netdevs of this class.  May be null if
  84      * no periodic work is necessary. */
  85     void (*run)(void);
  86
  87     /* Arranges for poll_block() to wake up if the "run" member function needs
  88      * to be called.  May be null if nothing is needed here. */
  89     void (*wait)(void);
  90
  91     /* Attempts to open a network device.  On success, sets '*netdevp' to the
  92      * new network device.  'name' is the full network device name provided by
  93      * the user.  This name is useful for error messages but must not be
  94      * modified.
  95      *
  96      * 'suffix' is a copy of 'name' following the netdev's 'prefix'.
  97      *
  98      * 'ethertype' may be a 16-bit Ethernet protocol value in host byte order
  99      * to capture frames of that type received on the device.  It may also be
 100      * one of the 'enum netdev_pseudo_ethertype' values to receive frames in
 101      * one of those categories. */
 102     int (*open)(const char *name, char *suffix, int ethertype,
 103                 struct netdev **netdevp);
 104
 105     /* Closes 'netdev'. */
 106     void (*close)(struct netdev *netdev);
 107
 108     /* Enumerates the names of all network devices of this class.
 109      *
 110      * The caller has already initialized 'all_names' and might already have
 111      * added some names to it.  This function should not disturb any existing
 112      * names in 'all_names'.
 113      *
 114      * If this netdev class does not support enumeration, this may be a null
 115      * pointer. */
 116     int (*enumerate)(struct svec *all_names);
 117
 118     /* Attempts to receive a packet from 'netdev' into the 'size' bytes in
 119      * 'buffer'.  If successful, returns the number of bytes in the received
 120      * packet, otherwise a negative errno value.  Returns -EAGAIN immediately
 121      * if no packet is ready to be received. */
 122     int (*recv)(struct netdev *netdev, void *buffer, size_t size);
 123
 124     /* Registers with the poll loop to wake up from the next call to
 125      * poll_block() when a packet is ready to be received with netdev_recv() on
 126      * 'netdev'. */
 127     void (*recv_wait)(struct netdev *netdev);
 128
 129     /* Discards all packets waiting to be received from 'netdev'. */
 130     int (*drain)(struct netdev *netdev);
 131
 132     /* Sends the 'size'-byte packet in 'buffer' on 'netdev'.  Returns 0 if
 133      * successful, otherwise a positive errno value.  Returns EAGAIN without
 134      * blocking if the packet cannot be queued immediately.  Returns EMSGSIZE
 135      * if a partial packet was transmitted or if the packet is too big or too
 136      * small to transmit on the device.
 137      *
 138      * The caller retains ownership of 'buffer' in all cases.
 139      *
 140      * The network device is expected to maintain a packet transmission queue,
 141      * so that the caller does not ordinarily have to do additional queuing of
 142      * packets. */
 143     int (*send)(struct netdev *netdev, const void *buffer, size_t size);
 144
 145     /* Registers with the poll loop to wake up from the next call to
 146      * poll_block() when the packet transmission queue for 'netdev' has
 147      * sufficient room to transmit a packet with netdev_send().
 148      *
 149      * The network device is expected to maintain a packet transmission queue,
 150      * so that the caller does not ordinarily have to do additional queuing of
 151      * packets.  Thus, this function is unlikely to ever be useful. */
 152     void (*send_wait)(struct netdev *netdev);
 153
 154     /* Sets 'netdev''s Ethernet address to 'mac' */
 155     int (*set_etheraddr)(struct netdev *netdev, const uint8_t mac[6]);
 156
 157     /* Retrieves 'netdev''s Ethernet address into 'mac'. */
 158     int (*get_etheraddr)(const struct netdev *netdev, uint8_t mac[6]);
 159
 160     /* Retrieves 'netdev''s MTU into '*mtup'.
 161      *
 162      * The MTU is the maximum size of transmitted (and received) packets, in
 163      * bytes, not including the hardware header; thus, this is typically 1500
 164      * bytes for Ethernet devices.*/
 165     int (*get_mtu)(const struct netdev *, int *mtup);
 166
 167     /* Sets 'carrier' to true if carrier is active (link light is on) on
 168      * 'netdev'. */
 169     int (*get_carrier)(const struct netdev *netdev, bool *carrier);
 170
 171     /* Retrieves current device stats for 'netdev' into 'stats'.
 172      *
 173      * A network device that supports some statistics but not others, it should
 174      * set the values of the unsupported statistics to all-1-bits
 175      * (UINT64_MAX). */
 176     int (*get_stats)(const struct netdev *netdev, struct netdev_stats *stats);
 177
 178     /* Stores the features supported by 'netdev' into each of '*current',
 179      * '*advertised', '*supported', and '*peer'.  Each value is a bitmap of
 180      * "enum ofp_port_features" bits, in host byte order. */
 181     int (*get_features)(struct netdev *netdev,
 182                         uint32_t *current, uint32_t *advertised,
 183                         uint32_t *supported, uint32_t *peer);
 184
 185     /* Set the features advertised by 'netdev' to 'advertise', which is a
 186      * bitmap of "enum ofp_port_features" bits, in host byte order.
 187      *
 188      * This function may be set to null for a network device that does not
 189      * support configuring advertisements. */
 190     int (*set_advertisements)(struct netdev *, uint32_t advertise);
 191
 192     /* If 'netdev' is a VLAN network device (e.g. one created with vconfig(8)),
 193      * sets '*vlan_vid' to the VLAN VID associated with that device and returns
 194      * 0.
 195      *
 196      * Returns ENOENT if 'netdev_name' is the name of a network device that is
 197      * not a VLAN device.
 198      *
 199      * This function should be set to null if it doesn't make any sense for
 200      * your network device (it probably doesn't). */
 201     int (*get_vlan_vid)(const struct netdev *netdev, int *vlan_vid);
 202
 203     /* Attempts to set input rate limiting (policing) policy, such that up to
 204      * 'kbits_rate' kbps of traffic is accepted, with a maximum accumulative
 205      * burst size of 'kbits' kb.
 206      *
 207      * This function may be set to null if policing is not supported. */
 208     int (*set_policing)(struct netdev *netdev, unsigned int kbits_rate,
 209                         unsigned int kbits_burst);
 210
 211     /* If 'netdev' has an assigned IPv4 address, sets '*address' to that
 212      * address and '*netmask' to the associated netmask.
 213      *
 214      * The following error values have well-defined meanings:
 215      *
 216      *   - EADDRNOTAVAIL: 'netdev' has no assigned IPv4 address.
 217      *
 218      *   - EOPNOTSUPP: No IPv4 network stack attached to 'netdev'.
 219      *
 220      * This function may be set to null if it would always return EOPNOTSUPP
 221      * anyhow. */
 222     int (*get_in4)(const struct netdev *netdev, struct in_addr *address,
 223                    struct in_addr *netmask);
 224
 225     /* Assigns 'addr' as 'netdev''s IPv4 address and 'mask' as its netmask.  If
 226      * 'addr' is INADDR_ANY, 'netdev''s IPv4 address is cleared.
 227      *
 228      * This function may be set to null if it would always return EOPNOTSUPP
 229      * anyhow. */
 230     int (*set_in4)(struct netdev *, struct in_addr addr, struct in_addr mask);
 231
 232     /* If 'netdev' has an assigned IPv6 address, sets '*in6' to that address.
 233      *
 234      * The following error values have well-defined meanings:
 235      *
 236      *   - EADDRNOTAVAIL: 'netdev' has no assigned IPv6 address.
 237      *
 238      *   - EOPNOTSUPP: No IPv6 network stack attached to 'netdev'.
 239      *
 240      * This function may be set to null if it would always return EOPNOTSUPP
 241      * anyhow. */
 242     int (*get_in6)(const struct netdev *netdev, struct in6_addr *in6);
 243
 244     /* Adds 'router' as a default IP gateway for the TCP/IP stack that
 245      * corresponds to 'netdev'.
 246      *
 247      * This function may be set to null if it would always return EOPNOTSUPP
 248      * anyhow. */
 249     int (*add_router)(struct netdev *netdev, struct in_addr router);
 250
 251     /* Looks up the next hop for 'host'.  If succesful, stores the next hop
 252      * gateway's address (0 if 'host' is on a directly connected network) in
 253      * '*next_hop' and a copy of the name of the device to reach 'host' in
 254      * '*netdev_name', and returns 0.  The caller is responsible for freeing
 255      * '*netdev_name' (by calling free()).
 256      *
 257      * This function may be set to null if it would always return EOPNOTSUPP
 258      * anyhow. */
 259     int (*get_next_hop)(const struct in_addr *host, struct in_addr *next_hop,
 260                         char **netdev_name);
 261
 262     /* Looks up the ARP table entry for 'ip' on 'netdev' and stores the
 263      * corresponding MAC address in 'mac'.  A return value of ENXIO, in
 264      * particular, indicates that there is no ARP table entry for 'ip' on
 265      * 'netdev'.
 266      *
 267      * This function may be set to null if it would always return EOPNOTSUPP
 268      * anyhow. */
 269     int (*arp_lookup)(const struct netdev *, uint32_t ip, uint8_t mac[6]);
 270
 271     /* Retrieves the current set of flags on 'netdev' into '*old_flags'.  Then,
 272      * turns off the flags that are set to 1 in 'off' and turns on the flags
 273      * that are set to 1 in 'on'.  (No bit will be set to 1 in both 'off' and
 274      * 'on'; that is, off & on == 0.)
 275      *
 276      * This function may be invoked from a signal handler.  Therefore, it
 277      * should not do anything that is not signal-safe (such as logging). */
 278     int (*update_flags)(struct netdev *netdev, enum netdev_flags off,
 279                         enum netdev_flags on, enum netdev_flags *old_flags);
 280
 281     /* Arranges for 'cb' to be called whenever one of the attributes of
 282      * 'netdev' changes and sets '*notifierp' to a newly created
 283      * netdev_notifier that represents this arrangement.  The created notifier
 284      * will have its 'netdev', 'cb', and 'aux' members set to the values of the
 285      * corresponding parameters. */
 286     int (*poll_add)(struct netdev *netdev,
 287                     void (*cb)(struct netdev_notifier *), void *aux,
 288                     struct netdev_notifier **notifierp);
 289
 290     /* Cancels poll notification for 'notifier'. */
 291     void (*poll_remove)(struct netdev_notifier *notifier);
 292 };
 293
 294 extern const struct netdev_class netdev_linux_class;
 295 extern const struct netdev_class netdev_tap_class;
 296
 297 #endif /* netdev.h */