Sock API

Provides a network API for applications and library.

About

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+---------------+
|  Application  |
+---------------+
        ^
        |
        v
      sock
        ^
        |
        v
+---------------+
| Network Stack |
+---------------+

This module provides a set of functions to establish connections or send and receive datagrams using different types of protocols. Together, they serve as an API that allows an application or library to connect to a network.

It was designed with the following priorities in mind

  1. No need for dynamic memory allocation
  2. User friendliness
  3. Simplicity
  4. Efficiency (at both front- and backend)
  5. Portability

Currently the following sock types are defined:

Note that there might be no relation between the different sock types. So casting e.g. sock_ip_t to sock_udp_t might not be as straight forward, as you think depending on the networking architecture.

How To Use

A RIOT application uses the functions provided by one or more of the sock type headers (for example sock/udp.h::sock_udp_t), regardless of the network stack it uses. The network stack used under the bonnet is specified by including the appropriate module (for example USEMODULE += gnrc_sock_udp for GNRC’s version of this API).

This allows for network stack agnostic code on the application layer. The application code to establish a connection is always the same, allowing the network stack underneath to be switched simply by changing the USEMODULE definitions in the application’s Makefile.

The actual code very much depends on the used sock type. Please refer to their documentation for specific examples.

Implementor Notes

Type definition

For simplicity and modularity this API doesn’t put any restriction on the actual implementation of the type. For example, one implementation might choose to have all sock types having a common base class or use the raw IP sock type to send e.g. UDP packets, while others will keep them completely separate from each other.

SOCK_HAS_IPV6

activate IPv6 support

SOCK_FLAGS_REUSE_EP

allow to reuse end point on bind 

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(0x0001)
SOCK_ADDR_ANY_NETIF

Special netif ID for “any interface”. 

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(0)

Use an equivalent defintion from PR #5511

SOCK_IPV4_EP_ANY

Address to bind to any IPv4 address. 

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{ .family = AF_INET, \
                                  .netif = SOCK_ADDR_ANY_NETIF }
SOCK_IPV6_EP_ANY

Address to bind to any IPv6 address. 

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{ .family = AF_INET6, \
                                  .netif = SOCK_ADDR_ANY_NETIF }
SOCK_NO_TIMEOUT

Special value meaning “wait forever” (don’t timeout) 

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(UINT32_MAX)
struct sock_ip_ep_t

Abstract IP end point and end point for a raw IP sock object.

int family

family of sock.h::sock_ip_ep_t::addr

See also

UNIX address families

uint8_t ipv6()

IPv6 address mode.

Note

only available if sock.h::SOCK_HAS_IPV6 is defined.

uint8_t ipv4()

IPv4 address mode.

uint32_t ipv4_u32

IPv4 address in network byte order

union sock_ip_ep_t::@198 addr

address

uint16_t netif

stack-specific network interface ID

port to common network interface identifiers in PR #5511.

Use sock.h::SOCK_ADDR_ANY_NETIF for any interface. For reception this is the local interface the message came over, for transmission, this is the local interface the message should be send over

struct _sock_tl_ep

Common IP-based transport layer end point.

int family

family of sock.h::sock_ip_ep_t::addr

See also

UNIX address families

uint8_t ipv6()

IPv6 address mode.

Note

only available if sock.h::SOCK_HAS_IPV6 is defined.

uint8_t ipv4()

IPv4 address mode.

uint32_t ipv4_u32

IPv4 address in network byte order

union _sock_tl_ep::@199 addr

address

uint16_t netif

stack-specific network interface ID

port to common network interface identifiers in PR #5511.

Use sock.h::SOCK_ADDR_ANY_NETIF for any interface. For reception this is the local interface the message came over, for transmission, this is the local interface the message should be send over

uint16_t port

transport layer port (in host byte order)