Network Interface

Overview

The network interface is a nexus that ties the network device drivers and the upper part of the network stack together. All the sent and received data is transferred via a network interface. The network interfaces cannot be created at runtime. A special linker section will contain information about them and that section is populated at linking time.

Network interfaces are created by NET_DEVICE_INIT() macro. For Ethernet network, a macro called ETH_NET_DEVICE_INIT() should be used instead as it will create VLAN interfaces automatically if CONFIG_NET_VLAN is enabled. These macros are typically used in network device driver source code.

The network interface can be turned ON by calling net_if_up() and OFF by calling net_if_down(). When the device is powered ON, the network interface is also turned ON by default.

The network interfaces can be referenced either by a struct net_if * pointer or by a network interface index. The network interface can be resolved from its index by calling net_if_get_by_index() and from interface pointer by calling net_if_get_by_iface().

The IP address for network devices must be set for them to be connectable. In a typical dynamic network environment, IP addresses are set automatically by DHCPv4, for example. If needed though, the application can set a device’s IP address manually. See the API documentation below for functions such as net_if_ipv4_addr_add() that do that.

The net_if_get_default() returns a default network interface. What this default interface means can be configured via options like CONFIG_NET_DEFAULT_IF_FIRST and CONFIG_NET_DEFAULT_IF_ETHERNET. See Kconfig file subsys/net/ip/Kconfig what options are available for selecting the default network interface.

The transmitted and received network packets can be classified via a network packet priority. This is typically done in Ethernet networks when virtual LANs (VLANs) are used. Higher priority packets can be sent or received earlier than lower priority packets. The traffic class setup can be configured by CONFIG_NET_TC_TX_COUNT and CONFIG_NET_TC_RX_COUNT options.

If the CONFIG_NET_PROMISCUOUS_MODE is enabled and if the underlying network technology supports promiscuous mode, then it is possible to receive all the network packets that the network device driver is able to receive. See Promiscuous Mode API for more details.

Network interface state management

Zephyr distinguishes between two interface states: administrative state and operational state, as described in RFC 2863. The administrative state indicate whether an interface is turned ON or OFF. This state is represented by NET_IF_UP flag and is controlled by the application. It can be changed by calling net_if_up() or net_if_down() functions. Network drivers or L2 implementations should not change administrative state on their own.

Bringing an interface up however not always means that the interface is ready to transmit packets. Because of that, operational state, which represents the internal interface status, was implemented. The operational state is updated whenever one of the following conditions take place:

  • The interface is brought up/down by the application (administrative state changes).

  • The interface is notified by the driver/L2 that PHY status has changed.

  • The interface is notified by the driver/L2 that it joined/left a network.

The PHY status is represented with NET_IF_LOWER_UP flag and can be changed with net_if_carrier_on() and net_if_carrier_off(). By default, the flag is set on a newly initialized interface. An example of an event that changes the carrier state is Ethernet cable being plugged in or out.

The network association status is represented with NET_IF_DORMANT flag and can be changed with net_if_dormant_on() and net_if_dormant_off(). By default, the flag is cleared on a newly initialized interface. An example of an event that changes the dormant state is a Wi-Fi driver successfully connecting to an access point. In this scenario, driver should set the dormant state to ON during initialization, and once it detects that it connected to a Wi-Fi network, the dormant state should be set to OFF.

The operational state of an interface is updated as follows:

Only after an interface enters NET_IF_OPER_UP state the NET_IF_RUNNING flag is set on the interface indicating that the interface is ready to be used by the application.

API Reference

group net_if

Network Interface abstraction layer.

Defines

NET_DEVICE_INIT(dev_id, name, init_fn, pm, data, config, prio, api, l2, l2_ctx_type, mtu)

Create a network interface and bind it to network device.

Parameters

  • dev_id – Network device id.

  • name – The name this instance of the driver exposes to the system.

  • init_fn – Address to the init function of the driver.

  • pm – Reference to struct pm_device associated with the device. (optional).

  • data – Pointer to the device’s private data.

  • config – The address to the structure containing the configuration information for this instance of the driver.

  • prio – The initialization level at which configuration occurs.

  • api – Provides an initial pointer to the API function struct used by the driver. Can be NULL.

  • l2 – Network L2 layer for this network interface.

  • l2_ctx_type – Type of L2 context data.

  • mtu – Maximum transfer unit in bytes for this network interface.

NET_DEVICE_DT_DEFINE(node_id, init_fn, pm, data, config, prio, api, l2, l2_ctx_type, mtu)

Like NET_DEVICE_INIT but taking metadata from a devicetree node. Create a network interface and bind it to network device.

Parameters

  • node_id – The devicetree node identifier.

  • init_fn – Address to the init function of the driver.

  • pm – Reference to struct pm_device associated with the device. (optional).

  • data – Pointer to the device’s private data.

  • config – The address to the structure containing the configuration information for this instance of the driver.

  • prio – The initialization level at which configuration occurs.

  • api – Provides an initial pointer to the API function struct used by the driver. Can be NULL.

  • l2 – Network L2 layer for this network interface.

  • l2_ctx_type – Type of L2 context data.

  • mtu – Maximum transfer unit in bytes for this network interface.

NET_DEVICE_DT_INST_DEFINE(inst, ...)

Like NET_DEVICE_DT_DEFINE for an instance of a DT_DRV_COMPAT compatible.

Parameters

  • inst – instance number. This is replaced by DT_DRV_COMPAT(inst) in the call to NET_DEVICE_DT_DEFINE.

  • ... – other parameters as expected by NET_DEVICE_DT_DEFINE.

NET_DEVICE_INIT_INSTANCE(dev_id, name, instance, init_fn, pm, data, config, prio, api, l2, l2_ctx_type, mtu)

Create multiple network interfaces and bind them to network device. If your network device needs more than one instance of a network interface, use this macro below and provide a different instance suffix each time (0, 1, 2, … or a, b, c … whatever works for you)

Parameters

  • dev_id – Network device id.

  • name – The name this instance of the driver exposes to the system.

  • instance – Instance identifier.

  • init_fn – Address to the init function of the driver.

  • pm – Reference to struct pm_device associated with the device. (optional).

  • data – Pointer to the device’s private data.

  • config – The address to the structure containing the configuration information for this instance of the driver.

  • prio – The initialization level at which configuration occurs.

  • api – Provides an initial pointer to the API function struct used by the driver. Can be NULL.

  • l2 – Network L2 layer for this network interface.

  • l2_ctx_type – Type of L2 context data.

  • mtu – Maximum transfer unit in bytes for this network interface.

NET_DEVICE_DT_DEFINE_INSTANCE(node_id, instance, init_fn, pm, data, config, prio, api, l2, l2_ctx_type, mtu)

Like NET_DEVICE_OFFLOAD_INIT but taking metadata from a devicetree. Create multiple network interfaces and bind them to network device. If your network device needs more than one instance of a network interface, use this macro below and provide a different instance suffix each time (0, 1, 2, … or a, b, c … whatever works for you)

Parameters

  • node_id – The devicetree node identifier.

  • instance – Instance identifier.

  • init_fn – Address to the init function of the driver.

  • pm – Reference to struct pm_device associated with the device. (optional).

  • data – Pointer to the device’s private data.

  • config – The address to the structure containing the configuration information for this instance of the driver.

  • prio – The initialization level at which configuration occurs.

  • api – Provides an initial pointer to the API function struct used by the driver. Can be NULL.

  • l2 – Network L2 layer for this network interface.

  • l2_ctx_type – Type of L2 context data.

  • mtu – Maximum transfer unit in bytes for this network interface.

NET_DEVICE_DT_INST_DEFINE_INSTANCE(inst, ...)

Like NET_DEVICE_DT_DEFINE_INSTANCE for an instance of a DT_DRV_COMPAT compatible.

Parameters

  • inst – instance number. This is replaced by DT_DRV_COMPAT(inst) in the call to NET_DEVICE_DT_DEFINE_INSTANCE.

  • ... – other parameters as expected by NET_DEVICE_DT_DEFINE_INSTANCE.

NET_DEVICE_OFFLOAD_INIT(dev_id, name, init_fn, pm, data, config, prio, api, mtu)

Create a offloaded network interface and bind it to network device. The offloaded network interface is implemented by a device vendor HAL or similar.

Parameters

  • dev_id – Network device id.

  • name – The name this instance of the driver exposes to the system.

  • init_fn – Address to the init function of the driver.

  • pm – Reference to struct pm_device associated with the device. (optional).

  • data – Pointer to the device’s private data.

  • config – The address to the structure containing the configuration information for this instance of the driver.

  • prio – The initialization level at which configuration occurs.

  • api – Provides an initial pointer to the API function struct used by the driver. Can be NULL.

  • mtu – Maximum transfer unit in bytes for this network interface.

NET_DEVICE_DT_OFFLOAD_DEFINE(node_id, init_fn, pm, data, config, prio, api, mtu)

Like NET_DEVICE_OFFLOAD_INIT but taking metadata from a devicetree node. Create a offloaded network interface and bind it to network device. The offloaded network interface is implemented by a device vendor HAL or similar.

Parameters

  • node_id – The devicetree node identifier.

  • init_fn – Address to the init function of the driver.

  • pm – Reference to struct pm_device associated with the device. (optional).

  • data – Pointer to the device’s private data.

  • config – The address to the structure containing the configuration information for this instance of the driver.

  • prio – The initialization level at which configuration occurs.

  • api – Provides an initial pointer to the API function struct used by the driver. Can be NULL.

  • mtu – Maximum transfer unit in bytes for this network interface.

NET_DEVICE_DT_INST_OFFLOAD_DEFINE(inst, ...)

Like NET_DEVICE_DT_OFFLOAD_DEFINE for an instance of a DT_DRV_COMPAT compatible.

Parameters

  • inst – instance number. This is replaced by DT_DRV_COMPAT(inst) in the call to NET_DEVICE_DT_OFFLOAD_DEFINE.

  • ... – other parameters as expected by NET_DEVICE_DT_OFFLOAD_DEFINE.

Typedefs

typedef int (*net_socket_create_t)(int, int, int)

A function prototype to create an offloaded socket. The prototype is compatible with socket() function.

typedef void (*net_if_mcast_callback_t)(struct net_if *iface, const struct net_addr *addr, bool is_joined)

Define callback that is called whenever IPv6 multicast address group is joined or left.

Param iface

A pointer to a struct net_if to which the multicast address is attached.

Param addr

IP multicast address.

Param is_joined

True if the address is joined, false if left.

Define callback that is called after a network packet has been sent.

Param iface

A pointer to a struct net_if to which the the net_pkt was sent to.

Param dst

Link layer address of the destination where the network packet was sent.

Param status

Send status, 0 is ok, < 0 error.

typedef void (*net_if_cb_t)(struct net_if *iface, void *user_data)

Callback used while iterating over network interfaces.

Param iface

Pointer to current network interface

Param user_data

A valid pointer to user data or NULL

Enums

enum net_if_flag

Network interface flags.

Values:

enumerator NET_IF_UP

Interface is admin up.

enumerator NET_IF_POINTOPOINT

Interface is pointopoint

enumerator NET_IF_PROMISC

Interface is in promiscuous mode

enumerator NET_IF_NO_AUTO_START

Do not start the interface immediately after initialization. This requires that either the device driver or some other entity will need to manually take the interface up when needed. For example for Ethernet this will happen when the driver calls the net_eth_carrier_on() function.

enumerator NET_IF_SUSPENDED

Power management specific: interface is being suspended

enumerator NET_IF_FORWARD_MULTICASTS

Flag defines if received multicasts of other interface are forwarded on this interface. This activates multicast routing / forwarding for this interface.

enumerator NET_IF_IPV4

Interface supports IPv4

enumerator NET_IF_IPV6

Interface supports IPv6

enumerator NET_IF_RUNNING

Interface up and running (ready to receive and transmit).

enumerator NET_IF_LOWER_UP

Driver signals L1 is up.

enumerator NET_IF_DORMANT

Driver signals dormant.

enum net_if_oper_state

Network interface operational status (RFC 2863).

Values:

enumerator NET_IF_OPER_UNKNOWN
enumerator NET_IF_OPER_NOTPRESENT
enumerator NET_IF_OPER_DOWN
enumerator NET_IF_OPER_LOWERLAYERDOWN
enumerator NET_IF_OPER_TESTING
enumerator NET_IF_OPER_DORMANT
enumerator NET_IF_OPER_UP

Functions

static inline void net_if_flag_set(struct net_if *iface, enum net_if_flag value)

Set a value in network interface flags.

Parameters

  • iface – Pointer to network interface

  • value – Flag value

static inline bool net_if_flag_test_and_set(struct net_if *iface, enum net_if_flag value)

Test and set a value in network interface flags.

Parameters

  • iface – Pointer to network interface

  • value – Flag value

Returns

true if the bit was set, false if it wasn’t.

static inline void net_if_flag_clear(struct net_if *iface, enum net_if_flag value)

Clear a value in network interface flags.

Parameters

  • iface – Pointer to network interface

  • value – Flag value

static inline bool net_if_flag_test_and_clear(struct net_if *iface, enum net_if_flag value)

Test and clear a value in network interface flags.

Parameters

  • iface – Pointer to network interface

  • value – Flag value

Returns

true if the bit was set, false if it wasn’t.

static inline bool net_if_flag_is_set(struct net_if *iface, enum net_if_flag value)

Check if a value in network interface flags is set.

Parameters

  • iface – Pointer to network interface

  • value – Flag value

Returns

True if the value is set, false otherwise

static inline enum net_if_oper_state net_if_oper_state_set(struct net_if *iface, enum net_if_oper_state oper_state)

Set an operational state on an interface.

Parameters

  • iface – Pointer to network interface

  • oper_state – Operational state to set

Returns

The new operational state of an interface

static inline enum net_if_oper_state net_if_oper_state(struct net_if *iface)

Get an operational state of an interface.

Parameters

  • iface – Pointer to network interface

Returns

Operational state of an interface

enum net_verdict net_if_send_data(struct net_if *iface, struct net_pkt *pkt)

Send a packet through a net iface.

return verdict about the packet

Parameters

  • iface – Pointer to a network interface structure

  • pkt – Pointer to a net packet to send

static inline const struct net_l2 *net_if_l2(struct net_if *iface)

Get a pointer to the interface L2.

Parameters

  • iface – a valid pointer to a network interface structure

Returns

a pointer to the iface L2

enum net_verdict net_if_recv_data(struct net_if *iface, struct net_pkt *pkt)

Input a packet through a net iface.

Parameters

  • iface – Pointer to a network interface structure

  • pkt – Pointer to a net packet to input

Returns

verdict about the packet

static inline void *net_if_l2_data(struct net_if *iface)

Get a pointer to the interface L2 private data.

Parameters

  • iface – a valid pointer to a network interface structure

Returns

a pointer to the iface L2 data

static inline const struct device *net_if_get_device(struct net_if *iface)

Get an network interface’s device.

Parameters

  • iface – Pointer to a network interface structure

Returns

a pointer to the device driver instance

void net_if_queue_tx(struct net_if *iface, struct net_pkt *pkt)

Queue a packet to the net interface TX queue.

Parameters

  • iface – Pointer to a network interface structure

  • pkt – Pointer to a net packet to queue

static inline bool net_if_is_ip_offloaded(struct net_if *iface)

Return the IP offload status.

Parameters

  • iface – Network interface

Returns

True if IP offloading is active, false otherwise.

static inline struct net_offload *net_if_offload(struct net_if *iface)

Return the IP offload plugin.

Parameters

  • iface – Network interface

Returns

NULL if there is no offload plugin defined, valid pointer otherwise

static inline bool net_if_is_socket_offloaded(struct net_if *iface)

Return the socket offload status.

Parameters

  • iface – Network interface

Returns

True if socket offloading is active, false otherwise.

static inline void net_if_socket_offload_set(struct net_if *iface, net_socket_create_t socket_offload)

Set the function to create an offloaded socket.

Parameters

  • iface – Network interface

  • socket_offload – A function to create an offloaded socket

static inline net_socket_create_t net_if_socket_offload(struct net_if *iface)

Return the function to create an offloaded socket.

Parameters

  • iface – Network interface

Returns

NULL if the interface is not socket offloaded, valid pointer otherwise

Get an network interface’s link address.

Parameters

  • iface – Pointer to a network interface structure

Returns

a pointer to the network link address

static inline struct net_if_config *net_if_get_config(struct net_if *iface)

Return network configuration for this network interface.

Parameters

  • iface – Pointer to a network interface structure

Returns

Pointer to configuration

static inline void net_if_start_dad(struct net_if *iface)

Start duplicate address detection procedure.

Parameters

  • iface – Pointer to a network interface structure

void net_if_start_rs(struct net_if *iface)

Start neighbor discovery and send router solicitation message.

Parameters

  • iface – Pointer to a network interface structure

static inline void net_if_stop_rs(struct net_if *iface)

Stop neighbor discovery.

Parameters

  • iface – Pointer to a network interface structure

Set a network interface’s link address.

Parameters

  • iface – Pointer to a network interface structure

  • addr – A pointer to a uint8_t buffer representing the address. The buffer must remain valid throughout interface lifetime.

  • len – length of the address buffer

  • type – network bearer type of this link address

Returns

0 on success

static inline uint16_t net_if_get_mtu(struct net_if *iface)

Get an network interface’s MTU.

Parameters

  • iface – Pointer to a network interface structure

Returns

the MTU

static inline void net_if_set_mtu(struct net_if *iface, uint16_t mtu)

Set an network interface’s MTU.

Parameters

  • iface – Pointer to a network interface structure

  • mtu – New MTU, note that we store only 16 bit mtu value.

static inline void net_if_addr_set_lf(struct net_if_addr *ifaddr, bool is_infinite)

Set the infinite status of the network interface address.

Parameters

  • ifaddr – IP address for network interface

  • is_infinite – Infinite status

Get an interface according to link layer address.

Parameters

  • ll_addr – Link layer address.

Returns

Network interface or NULL if not found.

struct net_if *net_if_lookup_by_dev(const struct device *dev)

Find an interface from it’s related device.

Parameters

  • dev – A valid struct device pointer to relate with an interface

Returns

a valid struct net_if pointer on success, NULL otherwise

static inline struct net_if_config *net_if_config_get(struct net_if *iface)

Get network interface IP config.

Parameters

  • iface – Interface to use.

Returns

NULL if not found or pointer to correct config settings.

void net_if_router_rm(struct net_if_router *router)

Remove a router from the system.

Parameters

  • router – Pointer to existing router

void net_if_set_default(struct net_if *iface)

Set the default network interface.

Parameters

  • iface – New default interface, or NULL to revert to the one set by Kconfig.

struct net_if *net_if_get_default(void)

Get the default network interface.

Returns

Default interface or NULL if no interfaces are configured.

struct net_if *net_if_get_first_by_type(const struct net_l2 *l2)

Get the first network interface according to its type.

Parameters

  • l2 – Layer 2 type of the network interface.

Returns

First network interface of a given type or NULL if no such interfaces was found.

struct net_if *net_if_get_first_up(void)

Get the first network interface which is up.

Returns

First network interface which is up or NULL if all interfaces are down.

int net_if_config_ipv6_get(struct net_if *iface, struct net_if_ipv6 **ipv6)

Allocate network interface IPv6 config.

This function will allocate new IPv6 config.

Parameters

  • iface – Interface to use.

  • ipv6 – Pointer to allocated IPv6 struct is returned to caller.

Returns

0 if ok, <0 if error

int net_if_config_ipv6_put(struct net_if *iface)

Release network interface IPv6 config.

Parameters

  • iface – Interface to use.

Returns

0 if ok, <0 if error

struct net_if_addr *net_if_ipv6_addr_lookup(const struct in6_addr *addr, struct net_if **iface)

Check if this IPv6 address belongs to one of the interfaces.

Parameters

  • addr – IPv6 address

  • iface – Pointer to interface is returned

Returns

Pointer to interface address, NULL if not found.

struct net_if_addr *net_if_ipv6_addr_lookup_by_iface(struct net_if *iface, struct in6_addr *addr)

Check if this IPv6 address belongs to this specific interfaces.

Parameters

  • iface – Network interface

  • addr – IPv6 address

Returns

Pointer to interface address, NULL if not found.

int net_if_ipv6_addr_lookup_by_index(const struct in6_addr *addr)

Check if this IPv6 address belongs to one of the interface indices.

Parameters

  • addr – IPv6 address

Returns

>0 if address was found in given network interface index, all other values mean address was not found

struct net_if_addr *net_if_ipv6_addr_add(struct net_if *iface, struct in6_addr *addr, enum net_addr_type addr_type, uint32_t vlifetime)

Add a IPv6 address to an interface.

Parameters

  • iface – Network interface

  • addr – IPv6 address

  • addr_type – IPv6 address type

  • vlifetime – Validity time for this address

Returns

Pointer to interface address, NULL if cannot be added

bool net_if_ipv6_addr_add_by_index(int index, struct in6_addr *addr, enum net_addr_type addr_type, uint32_t vlifetime)

Add a IPv6 address to an interface by index.

Parameters

  • index – Network interface index

  • addr – IPv6 address

  • addr_type – IPv6 address type

  • vlifetime – Validity time for this address

Returns

True if ok, false if address could not be added

void net_if_ipv6_addr_update_lifetime(struct net_if_addr *ifaddr, uint32_t vlifetime)

Update validity lifetime time of an IPv6 address.

Parameters

  • ifaddr – Network IPv6 address

  • vlifetime – Validity time for this address

bool net_if_ipv6_addr_rm(struct net_if *iface, const struct in6_addr *addr)

Remove an IPv6 address from an interface.

Parameters

  • iface – Network interface

  • addr – IPv6 address

Returns

True if successfully removed, false otherwise

bool net_if_ipv6_addr_rm_by_index(int index, const struct in6_addr *addr)

Remove an IPv6 address from an interface by index.

Parameters

  • index – Network interface index

  • addr – IPv6 address

Returns

True if successfully removed, false otherwise

struct net_if_mcast_addr *net_if_ipv6_maddr_add(struct net_if *iface, const struct in6_addr *addr)

Add a IPv6 multicast address to an interface.

Parameters

  • iface – Network interface

  • addr – IPv6 multicast address

Returns

Pointer to interface multicast address, NULL if cannot be added

bool net_if_ipv6_maddr_rm(struct net_if *iface, const struct in6_addr *addr)

Remove an IPv6 multicast address from an interface.

Parameters

  • iface – Network interface

  • addr – IPv6 multicast address

Returns

True if successfully removed, false otherwise

struct net_if_mcast_addr *net_if_ipv6_maddr_lookup(const struct in6_addr *addr, struct net_if **iface)

Check if this IPv6 multicast address belongs to a specific interface or one of the interfaces.

Parameters

  • addr – IPv6 address

  • iface – If *iface is null, then pointer to interface is returned, otherwise the *iface value needs to be matched.

Returns

Pointer to interface multicast address, NULL if not found.

void net_if_mcast_mon_register(struct net_if_mcast_monitor *mon, struct net_if *iface, net_if_mcast_callback_t cb)

Register a multicast monitor.

Parameters

  • mon – Monitor handle. This is a pointer to a monitor storage structure which should be allocated by caller, but does not need to be initialized.

  • iface – Network interface

  • cb – Monitor callback

void net_if_mcast_mon_unregister(struct net_if_mcast_monitor *mon)

Unregister a multicast monitor.

Parameters

  • mon – Monitor handle

void net_if_mcast_monitor(struct net_if *iface, const struct net_addr *addr, bool is_joined)

Call registered multicast monitors.

Parameters

  • iface – Network interface

  • addr – Multicast address

  • is_joined – Is this multicast address joined (true) or not (false)

void net_if_ipv6_maddr_join(struct net_if_mcast_addr *addr)

Mark a given multicast address to be joined.

Parameters

  • addr – IPv6 multicast address

static inline bool net_if_ipv6_maddr_is_joined(struct net_if_mcast_addr *addr)

Check if given multicast address is joined or not.

Parameters

  • addr – IPv6 multicast address

Returns

True if address is joined, False otherwise.

void net_if_ipv6_maddr_leave(struct net_if_mcast_addr *addr)

Mark a given multicast address to be left.

Parameters

  • addr – IPv6 multicast address

struct net_if_ipv6_prefix *net_if_ipv6_prefix_get(struct net_if *iface, struct in6_addr *addr)

Return prefix that corresponds to this IPv6 address.

Parameters

  • iface – Network interface

  • addr – IPv6 address

Returns

Pointer to prefix, NULL if not found.

struct net_if_ipv6_prefix *net_if_ipv6_prefix_lookup(struct net_if *iface, struct in6_addr *addr, uint8_t len)

Check if this IPv6 prefix belongs to this interface.

Parameters

  • iface – Network interface

  • addr – IPv6 address

  • len – Prefix length

Returns

Pointer to prefix, NULL if not found.

struct net_if_ipv6_prefix *net_if_ipv6_prefix_add(struct net_if *iface, struct in6_addr *prefix, uint8_t len, uint32_t lifetime)

Add a IPv6 prefix to an network interface.

Parameters

  • iface – Network interface

  • prefix – IPv6 address

  • len – Prefix length

  • lifetime – Prefix lifetime in seconds

Returns

Pointer to prefix, NULL if the prefix was not added.

bool net_if_ipv6_prefix_rm(struct net_if *iface, struct in6_addr *addr, uint8_t len)

Remove an IPv6 prefix from an interface.

Parameters

  • iface – Network interface

  • addr – IPv6 prefix address

  • len – Prefix length

Returns

True if successfully removed, false otherwise

static inline void net_if_ipv6_prefix_set_lf(struct net_if_ipv6_prefix *prefix, bool is_infinite)

Set the infinite status of the prefix.

Parameters

  • prefix – IPv6 address

  • is_infinite – Infinite status

void net_if_ipv6_prefix_set_timer(struct net_if_ipv6_prefix *prefix, uint32_t lifetime)

Set the prefix lifetime timer.

Parameters

  • prefix – IPv6 address

  • lifetime – Prefix lifetime in seconds

void net_if_ipv6_prefix_unset_timer(struct net_if_ipv6_prefix *prefix)

Unset the prefix lifetime timer.

Parameters

  • prefix – IPv6 address

Check if this IPv6 address is part of the subnet of our network interface.

Parameters

  • iface – Network interface. This is returned to the caller. The iface can be NULL in which case we check all the interfaces.

  • addr – IPv6 address

Returns

True if address is part of our subnet, false otherwise

static inline struct in6_addr *net_if_router_ipv6(struct net_if_router *router)

Get the IPv6 address of the given router.

Parameters

  • router – a network router

Returns

pointer to the IPv6 address, or NULL if none

struct net_if_router *net_if_ipv6_router_lookup(struct net_if *iface, struct in6_addr *addr)

Check if IPv6 address is one of the routers configured in the system.

Parameters

  • iface – Network interface

  • addr – IPv6 address

Returns

Pointer to router information, NULL if cannot be found

struct net_if_router *net_if_ipv6_router_find_default(struct net_if *iface, struct in6_addr *addr)

Find default router for this IPv6 address.

Parameters

  • iface – Network interface. This can be NULL in which case we go through all the network interfaces to find a suitable router.

  • addr – IPv6 address

Returns

Pointer to router information, NULL if cannot be found

void net_if_ipv6_router_update_lifetime(struct net_if_router *router, uint16_t lifetime)

Update validity lifetime time of a router.

Parameters

  • router – Network IPv6 address

  • lifetime – Lifetime of this router.

struct net_if_router *net_if_ipv6_router_add(struct net_if *iface, struct in6_addr *addr, uint16_t router_lifetime)

Add IPv6 router to the system.

Parameters

  • iface – Network interface

  • addr – IPv6 address

  • router_lifetime – Lifetime of the router

Returns

Pointer to router information, NULL if could not be added

bool net_if_ipv6_router_rm(struct net_if_router *router)

Remove IPv6 router from the system.

Parameters

  • router – Router information.

Returns

True if successfully removed, false otherwise

uint8_t net_if_ipv6_get_hop_limit(struct net_if *iface)

Get IPv6 hop limit specified for a given interface. This is the default value but can be overridden by the user.

Parameters

  • iface – Network interface

Returns

Hop limit

void net_ipv6_set_hop_limit(struct net_if *iface, uint8_t hop_limit)

Set the default IPv6 hop limit of a given interface.

Parameters

  • iface – Network interface

  • hop_limit – New hop limit

static inline void net_if_ipv6_set_base_reachable_time(struct net_if *iface, uint32_t reachable_time)

Set IPv6 reachable time for a given interface.

Parameters

  • iface – Network interface

  • reachable_time – New reachable time

static inline uint32_t net_if_ipv6_get_reachable_time(struct net_if *iface)

Get IPv6 reachable timeout specified for a given interface.

Parameters

  • iface – Network interface

Returns

Reachable timeout

uint32_t net_if_ipv6_calc_reachable_time(struct net_if_ipv6 *ipv6)

Calculate next reachable time value for IPv6 reachable time.

Parameters

  • ipv6 – IPv6 address configuration

Returns

Reachable time

static inline void net_if_ipv6_set_reachable_time(struct net_if_ipv6 *ipv6)

Set IPv6 reachable time for a given interface. This requires that base reachable time is set for the interface.

Parameters

  • ipv6 – IPv6 address configuration

static inline void net_if_ipv6_set_retrans_timer(struct net_if *iface, uint32_t retrans_timer)

Set IPv6 retransmit timer for a given interface.

Parameters

  • iface – Network interface

  • retrans_timer – New retransmit timer

static inline uint32_t net_if_ipv6_get_retrans_timer(struct net_if *iface)

Get IPv6 retransmit timer specified for a given interface.

Parameters

  • iface – Network interface

Returns

Retransmit timer

static inline const struct in6_addr *net_if_ipv6_select_src_addr(struct net_if *iface, const struct in6_addr *dst)

Get a IPv6 source address that should be used when sending network data to destination.

Parameters

  • iface – Interface that was used when packet was received. If the interface is not known, then NULL can be given.

  • dst – IPv6 destination address

Returns

Pointer to IPv6 address to use, NULL if no IPv6 address could be found.

static inline struct net_if *net_if_ipv6_select_src_iface(const struct in6_addr *dst)

Get a network interface that should be used when sending IPv6 network data to destination.

Parameters

  • dst – IPv6 destination address

Returns

Pointer to network interface to use, NULL if no suitable interface could be found.

struct in6_addr *net_if_ipv6_get_ll(struct net_if *iface, enum net_addr_state addr_state)

Get a IPv6 link local address in a given state.

Parameters

  • iface – Interface to use. Must be a valid pointer to an interface.

  • addr_state – IPv6 address state (preferred, tentative, deprecated)

Returns

Pointer to link local IPv6 address, NULL if no proper IPv6 address could be found.

struct in6_addr *net_if_ipv6_get_ll_addr(enum net_addr_state state, struct net_if **iface)

Return link local IPv6 address from the first interface that has a link local address matching give state.

Parameters

  • state – IPv6 address state (ANY, TENTATIVE, PREFERRED, DEPRECATED)

  • iface – Pointer to interface is returned

Returns

Pointer to IPv6 address, NULL if not found.

void net_if_ipv6_dad_failed(struct net_if *iface, const struct in6_addr *addr)

Stop IPv6 Duplicate Address Detection (DAD) procedure if we find out that our IPv6 address is already in use.

Parameters

  • iface – Interface where the DAD was running.

  • addr – IPv6 address that failed DAD

struct in6_addr *net_if_ipv6_get_global_addr(enum net_addr_state state, struct net_if **iface)

Return global IPv6 address from the first interface that has a global IPv6 address matching the given state.

Parameters

  • state – IPv6 address state (ANY, TENTATIVE, PREFERRED, DEPRECATED)

  • iface – Caller can give an interface to check. If iface is set to NULL, then all the interfaces are checked. Pointer to interface where the IPv6 address is defined is returned to the caller.

Returns

Pointer to IPv6 address, NULL if not found.

int net_if_config_ipv4_get(struct net_if *iface, struct net_if_ipv4 **ipv4)

Allocate network interface IPv4 config.

This function will allocate new IPv4 config.

Parameters

  • iface – Interface to use.

  • ipv4 – Pointer to allocated IPv4 struct is returned to caller.

Returns

0 if ok, <0 if error

int net_if_config_ipv4_put(struct net_if *iface)

Release network interface IPv4 config.

Parameters

  • iface – Interface to use.

Returns

0 if ok, <0 if error

uint8_t net_if_ipv4_get_ttl(struct net_if *iface)

Get IPv4 time-to-live value specified for a given interface.

Parameters

  • iface – Network interface

Returns

Time-to-live

void net_if_ipv4_set_ttl(struct net_if *iface, uint8_t ttl)

Set IPv4 time-to-live value specified to a given interface.

Parameters

  • iface – Network interface

  • ttl – Time-to-live value

struct net_if_addr *net_if_ipv4_addr_lookup(const struct in_addr *addr, struct net_if **iface)

Check if this IPv4 address belongs to one of the interfaces.

Parameters

  • addr – IPv4 address

  • iface – Interface is returned

Returns

Pointer to interface address, NULL if not found.

struct net_if_addr *net_if_ipv4_addr_add(struct net_if *iface, struct in_addr *addr, enum net_addr_type addr_type, uint32_t vlifetime)

Add a IPv4 address to an interface.

Parameters

  • iface – Network interface

  • addr – IPv4 address

  • addr_type – IPv4 address type

  • vlifetime – Validity time for this address

Returns

Pointer to interface address, NULL if cannot be added

bool net_if_ipv4_addr_rm(struct net_if *iface, const struct in_addr *addr)

Remove a IPv4 address from an interface.

Parameters

  • iface – Network interface

  • addr – IPv4 address

Returns

True if successfully removed, false otherwise

int net_if_ipv4_addr_lookup_by_index(const struct in_addr *addr)

Check if this IPv4 address belongs to one of the interface indices.

Parameters

  • addr – IPv4 address

Returns

>0 if address was found in given network interface index, all other values mean address was not found

bool net_if_ipv4_addr_add_by_index(int index, struct in_addr *addr, enum net_addr_type addr_type, uint32_t vlifetime)

Add a IPv4 address to an interface by network interface index.

Parameters

  • index – Network interface index

  • addr – IPv4 address

  • addr_type – IPv4 address type

  • vlifetime – Validity time for this address

Returns

True if ok, false if the address could not be added

bool net_if_ipv4_addr_rm_by_index(int index, const struct in_addr *addr)

Remove a IPv4 address from an interface by interface index.

Parameters

  • index – Network interface index

  • addr – IPv4 address

Returns

True if successfully removed, false otherwise

struct net_if_mcast_addr *net_if_ipv4_maddr_add(struct net_if *iface, const struct in_addr *addr)

Add a IPv4 multicast address to an interface.

Parameters

  • iface – Network interface

  • addr – IPv4 multicast address

Returns

Pointer to interface multicast address, NULL if cannot be added

bool net_if_ipv4_maddr_rm(struct net_if *iface, const struct in_addr *addr)

Remove an IPv4 multicast address from an interface.

Parameters

  • iface – Network interface

  • addr – IPv4 multicast address

Returns

True if successfully removed, false otherwise

struct net_if_mcast_addr *net_if_ipv4_maddr_lookup(const struct in_addr *addr, struct net_if **iface)

Check if this IPv4 multicast address belongs to a specific interface or one of the interfaces.

Parameters

  • addr – IPv4 address

  • iface – If *iface is null, then pointer to interface is returned, otherwise the *iface value needs to be matched.

Returns

Pointer to interface multicast address, NULL if not found.

void net_if_ipv4_maddr_join(struct net_if_mcast_addr *addr)

Mark a given multicast address to be joined.

Parameters

  • addr – IPv4 multicast address

static inline bool net_if_ipv4_maddr_is_joined(struct net_if_mcast_addr *addr)

Check if given multicast address is joined or not.

Parameters

  • addr – IPv4 multicast address

Returns

True if address is joined, False otherwise.

void net_if_ipv4_maddr_leave(struct net_if_mcast_addr *addr)

Mark a given multicast address to be left.

Parameters

  • addr – IPv4 multicast address

static inline struct in_addr *net_if_router_ipv4(struct net_if_router *router)

Get the IPv4 address of the given router.

Parameters

  • router – a network router

Returns

pointer to the IPv4 address, or NULL if none

struct net_if_router *net_if_ipv4_router_lookup(struct net_if *iface, struct in_addr *addr)

Check if IPv4 address is one of the routers configured in the system.

Parameters

  • iface – Network interface

  • addr – IPv4 address

Returns

Pointer to router information, NULL if cannot be found

struct net_if_router *net_if_ipv4_router_find_default(struct net_if *iface, struct in_addr *addr)

Find default router for this IPv4 address.

Parameters

  • iface – Network interface. This can be NULL in which case we go through all the network interfaces to find a suitable router.

  • addr – IPv4 address

Returns

Pointer to router information, NULL if cannot be found

struct net_if_router *net_if_ipv4_router_add(struct net_if *iface, struct in_addr *addr, bool is_default, uint16_t router_lifetime)

Add IPv4 router to the system.

Parameters

  • iface – Network interface

  • addr – IPv4 address

  • is_default – Is this router the default one

  • router_lifetime – Lifetime of the router

Returns

Pointer to router information, NULL if could not be added

bool net_if_ipv4_router_rm(struct net_if_router *router)

Remove IPv4 router from the system.

Parameters

  • router – Router information.

Returns

True if successfully removed, false otherwise

bool net_if_ipv4_addr_mask_cmp(struct net_if *iface, const struct in_addr *addr)

Check if the given IPv4 address belongs to local subnet.

Parameters

  • iface – Interface to use. Must be a valid pointer to an interface.

  • addr – IPv4 address

Returns

True if address is part of local subnet, false otherwise.

bool net_if_ipv4_is_addr_bcast(struct net_if *iface, const struct in_addr *addr)

Check if the given IPv4 address is a broadcast address.

Parameters

  • iface – Interface to use. Must be a valid pointer to an interface.

  • addr – IPv4 address, this should be in network byte order

Returns

True if address is a broadcast address, false otherwise.

static inline struct net_if *net_if_ipv4_select_src_iface(const struct in_addr *dst)

Get a network interface that should be used when sending IPv4 network data to destination.

Parameters

  • dst – IPv4 destination address

Returns

Pointer to network interface to use, NULL if no suitable interface could be found.

static inline const struct in_addr *net_if_ipv4_select_src_addr(struct net_if *iface, const struct in_addr *dst)

Get a IPv4 source address that should be used when sending network data to destination.

Parameters

  • iface – Interface to use when sending the packet. If the interface is not known, then NULL can be given.

  • dst – IPv4 destination address

Returns

Pointer to IPv4 address to use, NULL if no IPv4 address could be found.

struct in_addr *net_if_ipv4_get_ll(struct net_if *iface, enum net_addr_state addr_state)

Get a IPv4 link local address in a given state.

Parameters

  • iface – Interface to use. Must be a valid pointer to an interface.

  • addr_state – IPv4 address state (preferred, tentative, deprecated)

Returns

Pointer to link local IPv4 address, NULL if no proper IPv4 address could be found.

struct in_addr *net_if_ipv4_get_global_addr(struct net_if *iface, enum net_addr_state addr_state)

Get a IPv4 global address in a given state.

Parameters

  • iface – Interface to use. Must be a valid pointer to an interface.

  • addr_state – IPv4 address state (preferred, tentative, deprecated)

Returns

Pointer to link local IPv4 address, NULL if no proper IPv4 address could be found.

void net_if_ipv4_set_netmask(struct net_if *iface, const struct in_addr *netmask)

Set IPv4 netmask for an interface.

Parameters

  • iface – Interface to use.

  • netmask – IPv4 netmask

bool net_if_ipv4_set_netmask_by_index(int index, const struct in_addr *netmask)

Set IPv4 netmask for an interface index.

Parameters

  • index – Network interface index

  • netmask – IPv4 netmask

Returns

True if netmask was added, false otherwise.

void net_if_ipv4_set_gw(struct net_if *iface, const struct in_addr *gw)

Set IPv4 gateway for an interface.

Parameters

  • iface – Interface to use.

  • gw – IPv4 address of an gateway

bool net_if_ipv4_set_gw_by_index(int index, const struct in_addr *gw)

Set IPv4 gateway for an interface index.

Parameters

  • index – Network interface index

  • gw – IPv4 address of an gateway

Returns

True if gateway was added, false otherwise.

struct net_if *net_if_select_src_iface(const struct sockaddr *dst)

Get a network interface that should be used when sending IPv6 or IPv4 network data to destination.

Parameters

  • dst – IPv6 or IPv4 destination address

Returns

Pointer to network interface to use. Note that the function will return the default network interface if the best network interface is not found.

Register a link callback.

Parameters

  • link – Caller specified handler for the callback.

  • cb – Callback to register.

Unregister a link callback.

Parameters

  • link – Caller specified handler for the callback.

Call a link callback function.

Parameters

  • iface – Network interface.

  • lladdr – Destination link layer address

  • status – 0 is ok, < 0 error

bool net_if_need_calc_rx_checksum(struct net_if *iface)

Check if received network packet checksum calculation can be avoided or not. For example many ethernet devices support network packet offloading in which case the IP stack does not need to calculate the checksum.

Parameters

  • iface – Network interface

Returns

True if checksum needs to be calculated, false otherwise.

bool net_if_need_calc_tx_checksum(struct net_if *iface)

Check if network packet checksum calculation can be avoided or not when sending the packet. For example many ethernet devices support network packet offloading in which case the IP stack does not need to calculate the checksum.

Parameters

  • iface – Network interface

Returns

True if checksum needs to be calculated, false otherwise.

struct net_if *net_if_get_by_index(int index)

Get interface according to index.

This is a syscall only to provide access to the object for purposes of assigning permissions.

Parameters

  • index – Interface index

Returns

Pointer to interface or NULL if not found.

int net_if_get_by_iface(struct net_if *iface)

Get interface index according to pointer.

Parameters

  • iface – Pointer to network interface

Returns

Interface index

void net_if_foreach(net_if_cb_t cb, void *user_data)

Go through all the network interfaces and call callback for each interface.

Parameters

  • cb – User-supplied callback function to call

  • user_data – User specified data

int net_if_up(struct net_if *iface)

Bring interface up.

Parameters

  • iface – Pointer to network interface

Returns

0 on success

static inline bool net_if_is_up(struct net_if *iface)

Check if interface is is up and running.

Parameters

  • iface – Pointer to network interface

Returns

True if interface is up, False if it is down.

int net_if_down(struct net_if *iface)

Bring interface down.

Parameters

  • iface – Pointer to network interface

Returns

0 on success

static inline bool net_if_is_admin_up(struct net_if *iface)

Check if interface was brought up by the administrator.

Parameters

  • iface – Pointer to network interface

Returns

True if interface is admin up, false otherwise.

void net_if_carrier_on(struct net_if *iface)

Underlying network device has detected the carrier (cable connected).

The function should be used by the respective network device driver or L2 implementation to update its state on a network interface.

Parameters

  • iface – Pointer to network interface

void net_if_carrier_off(struct net_if *iface)

Underlying network device has lost the carrier (cable disconnected).

The function should be used by the respective network device driver or L2 implementation to update its state on a network interface.

Parameters

  • iface – Pointer to network interface

static inline bool net_if_is_carrier_ok(struct net_if *iface)

Check if carrier is present on network device.

Parameters

  • iface – Pointer to network interface

Returns

True if carrier is present, false otherwise.

void net_if_dormant_on(struct net_if *iface)

Mark interface as dormant. Dormant state indicates that the interface is not ready to pass packets yet, but is waiting for some event (for example Wi-Fi network association).

The function should be used by the respective network device driver or L2 implementation to update its state on a network interface.

Parameters

  • iface – Pointer to network interface

void net_if_dormant_off(struct net_if *iface)

Mark interface as not dormant.

The function should be used by the respective network device driver or L2 implementation to update its state on a network interface.

Parameters

  • iface – Pointer to network interface

static inline bool net_if_is_dormant(struct net_if *iface)

Check if the interface is dormant.

Parameters

  • iface – Pointer to network interface

Returns

True if interface is dormant, false otherwise.

int net_if_set_promisc(struct net_if *iface)

Set network interface into promiscuous mode.

Note that not all network technologies will support this.

Parameters

  • iface – Pointer to network interface

Returns

0 on success, <0 if error

void net_if_unset_promisc(struct net_if *iface)

Set network interface into normal mode.

Parameters

  • iface – Pointer to network interface

bool net_if_is_promisc(struct net_if *iface)

Check if promiscuous mode is set or not.

Parameters

  • iface – Pointer to network interface

Returns

True if interface is in promisc mode, False if interface is not in in promiscuous mode.

static inline bool net_if_are_pending_tx_packets(struct net_if *iface)

Check if there are any pending TX network data for a given network interface.

Parameters

  • iface – Pointer to network interface

Returns

True if there are pending TX network packets for this network interface, False otherwise.

struct net_if_addr
#include <net_if.h>

Network Interface unicast IP addresses.

Stores the unicast IP addresses assigned to this network interface.

Public Members

struct net_addr address

IP address

enum net_addr_type addr_type

How the IP address was set

enum net_addr_state addr_state

What is the current state of the address

uint8_t is_infinite

Is the IP address valid forever

uint8_t is_used

Is this IP address used or not

uint8_t is_mesh_local

Is this IP address usage limited to the subnet (mesh) or not

struct net_if_mcast_addr
#include <net_if.h>

Network Interface multicast IP addresses.

Stores the multicast IP addresses assigned to this network interface.

Public Members

struct net_addr address

IP address

uint8_t is_used

Is this multicast IP address used or not

uint8_t is_joined

Did we join to this group

struct net_if_ipv6_prefix
#include <net_if.h>

Network Interface IPv6 prefixes.

Stores the multicast IP addresses assigned to this network interface.

Public Members

struct net_timeout lifetime

Prefix lifetime

struct in6_addr prefix

IPv6 prefix

struct net_if *iface

Backpointer to network interface where this prefix is used

uint8_t len

Prefix length

uint8_t is_infinite

Is the IP prefix valid forever

uint8_t is_used

Is this prefix used or not

struct net_if_router
#include <net_if.h>

Information about routers in the system.

Stores the router information.

Public Members

sys_snode_t node

Slist lifetime timer node

struct net_addr address

IP address

struct net_if *iface

Network interface the router is connected to

uint32_t life_start

Router life timer start

uint16_t lifetime

Router lifetime

uint8_t is_used

Is this router used or not

uint8_t is_default

Is default router

uint8_t is_infinite

Is the router valid forever

struct net_if_ipv6
#include <net_if.h>

Public Members

struct net_if_addr unicast[NET_IF_MAX_IPV6_ADDR]

Unicast IP addresses

struct net_if_mcast_addr mcast[NET_IF_MAX_IPV6_MADDR]

Multicast IP addresses

struct net_if_ipv6_prefix prefix[NET_IF_MAX_IPV6_PREFIX]

Prefixes

uint32_t base_reachable_time

Default reachable time (RFC 4861, page 52)

uint32_t reachable_time

Reachable time (RFC 4861, page 20)

uint32_t retrans_timer

Retransmit timer (RFC 4861, page 52)

uint8_t hop_limit

IPv6 hop limit

struct net_if_ipv4
#include <net_if.h>

Public Members

struct net_if_addr unicast[NET_IF_MAX_IPV4_ADDR]

Unicast IP addresses

struct net_if_mcast_addr mcast[NET_IF_MAX_IPV4_MADDR]

Multicast IP addresses

struct in_addr gw

Gateway

struct in_addr netmask

Netmask

uint8_t ttl

IPv4 time-to-live

struct net_if_ip
#include <net_if.h>

Network interface IP address configuration.

struct net_if_config
#include <net_if.h>

IP and other configuration related data for network interface.

struct net_traffic_class
#include <net_if.h>

Network traffic class.

Traffic classes are used when sending or receiving data that is classified with different priorities. So some traffic can be marked as high priority and it will be sent or received first. Each network packet that is transmitted or received goes through a fifo to a thread that will transmit it.

Public Members

struct k_fifo fifo

Fifo for handling this Tx or Rx packet

struct k_thread handler

Traffic class handler thread

k_thread_stack_t *stack

Stack for this handler

struct net_if_dev
#include <net_if.h>

Network Interface Device structure.

Used to handle a network interface on top of a device driver instance. There can be many net_if_dev instance against the same device.

Such interface is mainly to be used by the link layer, but is also tight to a network context: it then makes the relation with a network context and the network device.

Because of the strong relationship between a device driver and such network interface, each net_if_dev should be instantiated by

Public Members

const struct device *dev

The actually device driver instance the net_if is related to

const struct net_l2 *const l2

Interface’s L2 layer

void *l2_data

Interface’s private L2 data pointer

The hardware link address

uint16_t mtu

The hardware MTU

enum net_if_oper_state oper_state

RFC 2863 operational status

struct net_if
#include <net_if.h>

Network Interface structure.

Used to handle a network interface on top of a net_if_dev instance. There can be many net_if instance against the same net_if_dev instance.

Public Members

struct net_if_dev *if_dev

The net_if_dev instance the net_if is related to

struct net_if_config config

Network interface instance configuration

struct net_if_mcast_monitor
#include <net_if.h>

Multicast monitor handler struct.

Stores the multicast callback information. Caller must make sure that the variable pointed by this is valid during the lifetime of registration. Typically this means that the variable cannot be allocated from stack.

Public Members

sys_snode_t node

Node information for the slist.

struct net_if *iface

Network interface

net_if_mcast_callback_t cb

Multicast callback

#include <net_if.h>

Link callback handler struct.

Stores the link callback information. Caller must make sure that the variable pointed by this is valid during the lifetime of registration. Typically this means that the variable cannot be allocated from stack.

Public Members

Node information for the slist.

Link callback