Sockets

Sockets. More...

Modules
	Socket Types
	Socket types.

Data Structures
struct	socket_t
	Socket structure. More...

Enumerations
enum	socket_state_t {   SOCKET_NEW ,   SOCKET_BOUND ,   SOCKET_LISTENING ,   SOCKET_CONNECTING ,   SOCKET_CONNECTED ,   SOCKET_CLOSING ,   SOCKET_CLOSED ,   SOCKET_STATE_AMOUNT }
	Socket states. More...

Functions
socket_t *	socket_new (socket_family_t *family, socket_type_t type, path_flags_t flags)
	Create a new socket.
uint64_t	socket_start_transition (socket_t *sock, socket_state_t state)
	Starts a socket state transition.
void	socket_continue_transition (socket_t *sock, socket_state_t state)
	Without releasing the socket mutex, start a transition to a new target state.
void	socket_end_transition (socket_t *sock, uint64_t result)
	Ends a socket state transition.

Detailed Description

Sockets.

Sockets are exposed in the /net directory. Sockets provide communication endpoints for networking.

Creating Sockets

Sockets are created by opening a factory located in each socket families directory. For example, to create a local seqpacket socket, open the /net/local/seqpacket/ file which gives you a handle that when read returns the socket's ID, which corresponds to the path /net/<family_name>/<socket_id>/, for example /net/local/1234/, which stores the files used to interact with the socket.

Using Sockets

Sockets are interacted with using the following files located in their directory.

accept

The /net/<family_name>/<socket_id>/accept file can be opened on a listening socket to accept incoming connections. Working in an similiar way to the POSIX accept() function, the returned file descriptor represents the new connection.

If opened with :nonblock and there are no incoming connections, the open will fail with EAGAIN, otherwise it will block until a connection is available.

ctl

The /net/<family_name>/<socket_id>/ctl file is used to send "commands" to the socket. Here is a list of supported commands:

• bind <address>: Binds the socket to the specified address. (POSIX bind() function)
• listen <backlog>: Puts the socket into listening mode with the specified backlog length. (POSIX listen() function)
• connect <address>: Connects the socket to the specified address. (POSIX connect() function)

data

The /net/<family_name>/<socket_id>/data file is used to send and retrieve data using the socket. Writing to this file sends data, reading from it receives data. (POSIX send() and recv() functions)

If opened with :nonblock, read and write operations will fail with EAGAIN if no data is available or there is no buffer space available, respectively, otherwise they will block, waiting for data or buffer space.

Enumeration Type Documentation

socket_state_t

enum socket_state_t

Socket states.

Enumerator
SOCKET_NEW
SOCKET_BOUND
SOCKET_LISTENING
SOCKET_CONNECTING
SOCKET_CONNECTED
SOCKET_CLOSING
SOCKET_CLOSED
SOCKET_STATE_AMOUNT

Definition at line 64 of file socket.h.

Function Documentation

socket_continue_transition()

void socket_continue_transition	(	socket_t *	sock,
		socket_state_t	state
	)

Without releasing the socket mutex, start a transition to a new target state.

Parameters

sock	Pointer to the socket.
state	Target state.

Definition at line 519 of file socket.c.

References assert, socket_t::currentState, socket_t::nextState, and socket_can_transition().

Referenced by socket_accept_open(), and socket_ctl_connect().

socket_end_transition()

void socket_end_transition	(	socket_t *	sock,
		uint64_t	result
	)

Ends a socket state transition.

Parameters

sock	Pointer to the socket.
result	Result of the transition, if ERR the transition failed.

Definition at line 528 of file socket.c.

References socket_t::currentState, ERR, socket_t::mutex, socket_t::nextState, and rwmutex_write_release().

Referenced by socket_accept_open(), socket_ctl_bind(), socket_ctl_connect(), and socket_ctl_listen().

socket_new()

socket_t * socket_new	(	socket_family_t *	family,
		socket_type_t	type,
		path_flags_t	flags
	)

Create a new socket.

There is no socket_free() function, instead use DEREF() to free the socket.

Parameters

family	Pointer to the socket family.
type	Socket type.
flags	Path flags.

Returns

On success, pointer to the new socket. On failure, NULL and errno is set.

Definition at line 359 of file socket.c.

References socket_t::acceptFile, acceptOps, atomic_fetch_add, calloc(), socket_t::ctlFile, socket_t::currentState, socket_t::dataFile, dataOps, socket_family_ops_t::deinit, DEREF, EINVAL, ENOMEM, ERR, errno, socket_t::family, socket_t::flags, free(), socket_t::id, socket_family_ops_t::init, inodeOps, mount, socket_t::mutex, socket_family_t::newId, socket_t::nextState, NULL, socket_family_t::ops, PATH_EMPTY, path_put(), superblock_t::private, socket_t::private, socket_t::ref, REF, ref_init(), mount_t::root, rwmutex_deinit(), rwmutex_init(), sched_process(), snprintf(), socket_family_get_dir(), socket_free(), SOCKET_NEW, mount_t::superblock, superblockOps, sysfs_file_new(), sysfs_mount_new(), and socket_t::type.

Referenced by socket_accept_open(), and socket_factory_open().

socket_start_transition()

uint64_t socket_start_transition	(	socket_t *	sock,
		socket_state_t	state
	)

Starts a socket state transition.

Parameters

sock	Pointer to the socket.
state	Target state.

Returns

On success, 0. On failure, ERR and errno is set.

Definition at line 491 of file socket.c.

References socket_t::currentState, EINVAL, ERR, errno, socket_t::mutex, socket_t::nextState, NULL, rwmutex_write_acquire(), rwmutex_write_release(), and socket_can_transition().

Referenced by socket_accept_open(), socket_ctl_bind(), socket_ctl_connect(), and socket_ctl_listen().