io\_uring\_prep\_cmd\_sock(3) liburing Manual io\_uring\_prep\_cmd\_sock(3) # [NAME](#NAME) io\_uring\_prep\_cmd\_sock - prepare a command request for a socket # [SYNOPSIS](#SYNOPSIS) ``` #include ``` ``` void io_uring_prep_cmd_sock(struct io_uring_sqe *sqe, int cmd_op, int fd, int level, int optname, void *optval, int optlen); ``` # [DESCRIPTION](#DESCRIPTION) The [**io\_uring\_prep\_cmd\_sock**(3)](/man/os/liburing/io_uring_prep_cmd_sock.3) function prepares an cmd request for a socket. The submission queue entry *sqe* is setup to use the socket file descriptor pointed to by *fd* to start an command operation defined by *cmd\_op.* This is a generic function, and each command has their own individual *level, optname, optval* values. The optlen defines the size pointed by *optval.* # [Available commands](#Available_commands) [**SOCKET\_URING\_OP\_SIOCINQ**](#SOCKET_URING_OP_SIOCINQ) Returns the amount of queued unread data in the receive buffer. The socket must not be in LISTEN state, otherwise an error **-EINVAL** is returned in the CQE *res* field. The following arguments are not used for this command *level, optname, optval* and *optlen.* Negative return value means an error. For more information about this command, please check **[unix(7)](/man/os/liburing/unix.7).** Available since 6.7. [**SOCKET\_URING\_OP\_SIOCOUTQ**](#SOCKET_URING_OP_SIOCOUTQ) Returns the amount of unsent data in the socket send queue. The socket must not be in LISTEN state, otherwise an error **-EINVAL** is returned in the CQE *res.* field. The following arguments are not used for this command *level, optname, optval* and *optlen.* Negative return value means an error. For more information about this command, please check **[unix(7)](/man/os/liburing/unix.7).** [**SOCKET\_URING\_OP\_GETSOCKOPT**](#SOCKET_URING_OP_GETSOCKOPT) Command to get options for the socket referred to by the socket file descriptor *fd.* The arguments are similar to the [**getsockopt(2)**](/man/os/liburing/getsockopt.2) system call. The **SOCKET\_URING\_OP\_GETSOCKOPT** command is limited to **SOL\_SOCKET** *level.* Differently from the [**getsockopt(2)**](/man/os/liburing/getsockopt.2) system call, the updated *optlen* value is returned in the CQE *res* field, on success. On failure, the CQE *res* contains a negative error number. [**SOCKET\_URING\_OP\_SETSOCKOPT**](#SOCKET_URING_OP_SETSOCKOPT) Command to set options for the socket referred to by the socket file descriptor *fd.* The arguments are similar to the [**setsockopt(2)**](/man/os/liburing/setsockopt.2) system call. Available since 6.7. [**SOCKET\_URING\_OP\_TX\_TIMESTAMP**](#SOCKET_URING_OP_TX_TIMESTAMP) Retrieve transmit timestamps from the socket's error queue. This provides an alternative to the traditional [**recvmsg(2)**](/man/os/liburing/recvmsg.2) error queue interface for obtaining TX timestamps. The command operates in a polled multishot mode: io\_uring will poll the socket and keep posting timestamps as CQEs until the request is cancelled or fails. The ring must be created with **IORING\_SETUP\_CQE32** or **IORING\_SETUP\_CQE\_MIXED** to provide space for the timestamp data. The socket must first be configured for timestamping via [**setsockopt(2)**](/man/os/liburing/setsockopt.2) with **SO\_TIMESTAMPING** at the **SOL\_SOCKET** level, specifying the desired timestamp types (e.g. **SOF\_TIMESTAMPING\_TX\_SOFTWARE**, **SOF\_TIMESTAMPING\_TX\_SCHED**, **SOF\_TIMESTAMPING\_TX\_ACK**) along with **SOF\_TIMESTAMPING\_SOFTWARE** and **SOF\_TIMESTAMPING\_OPT\_TSONLY**. The following arguments are not used for this command: *level, optname, optval* and *optlen.* Each timestamp is delivered as a CQE with **IORING\_CQE\_F\_MORE** set in *cqe->flags* to indicate more timestamps may follow. The *cqe->res* field contains the timestamp key (*tskey*), which corresponds to the byte offset (for TCP) or packet count (for UDP). The timestamp type (*SCM\_TSTAMP\_SCHED*, *SCM\_TSTAMP\_SND* or *SCM\_TSTAMP\_ACK*) is stored in the upper bits of *cqe->flags* at offset **IORING\_TIMESTAMP\_TYPE\_SHIFT**. If the timestamp is a hardware timestamp, the **IORING\_CQE\_F\_TSTAMP\_HW** flag is set. The actual timestamp value is stored in the extended CQE area as a **struct io\_timespec** (with 64-bit *tv\_sec* and *tv\_nsec* fields), accessible at *(cqe + 1)*. The final CQE will not have **IORING\_CQE\_F\_MORE** set, and its *cqe->res* will contain 0 on success or a negative error code on failure. Available since 6.17. [**SOCKET\_URING\_OP\_GETSOCKNAME**](#SOCKET_URING_OP_GETSOCKNAME) Returns the current address to which the socket is bound. The result is stored in the buffer pointed to by *optval,* which should be a pointer to a *struct sockaddr* (or appropriate variant). The *optlen* argument specifies the size of the buffer. On success, the CQE *res* field contains the actual size of the socket address. If the buffer is too small, the result is truncated. This is the io\_uring equivalent of [**getsockname**(2)](/man/os/liburing/getsockname.2). Available since 6.19. # [NOTES](#NOTES) The memory block pointed by *optval* needs to be valid/live until the CQE returns. # [RETURN VALUE](#RETURN_VALUE) Dependent on the command. # [ERRORS](#ERRORS) The CQE *res* field will contain the result of the operation. # [SEE ALSO](#SEE_ALSO) [**io\_uring\_get\_sqe**(3)](/man/os/liburing/io_uring_get_sqe.3), [**io\_uring\_submit**(3)](/man/os/liburing/io_uring_submit.3), [**io\_uring\_register**(2)](/man/os/liburing/io_uring_register.2), [**unix**(7)](/man/os/liburing/unix.7) July 27, 2023 liburing-2.5 --- Document: io_uring_prep_cmd_sock(3) from liburing 2.15-r4 (Chainguard OS) Source: https://github.com/axboe/liburing.git