udp

stable

UDP socket plugin for sending and receiving datagrams. Provides a UdpSocket class with full control over binding, timeouts, broadcast, TTL, and blocking mode.

use plugin udp::{UdpSocket, send_to, recv, …}

13 functions Networking

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Functions (13)

UdpSocket Creates a UDP socket and binds it to the given address.
send_to Sends data as a string to the specified remote addr.
recv Blocks until a datagram arrives and returns a table with data (string) and addr (source address string).
local_addr Returns the local address the socket is bound to, e.g.
set_nonblocking Switches the socket between blocking (default) and non-blocking mode.
set_broadcast Enables or disables the SO_BROADCAST socket option, required before sending to broadcast addresses like 255.255.255.255.
set_read_timeout Sets a read timeout in milliseconds.
set_write_timeout Sets a write timeout in milliseconds.
connect Associates a default remote address with the socket.
send Sends data to the address previously set with connect.
peek Reads up to buf_size bytes without removing the datagram from the queue.
set_ttl Sets the IP Time-To-Live (hop count) for outgoing packets.
ttl Returns the current IP TTL value set on the socket.

UdpSocket(bind_addr) → handle

Creates a UDP socket and binds it to the given address.

Creates a UDP socket and binds it to the given address. Use "0.0.0.0:0" to bind to any available port, or specify a port like "0.0.0.0:9000".

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:9000")
print("Listening on {sock.local_addr()}")

send_to(socket, data, addr) → int

Sends data as a string to the specified remote addr.

Sends data as a string to the specified remote addr. Returns the number of bytes sent.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
let sent = sock.send_to("hello", "127.0.0.1:9000")
print("Sent {sent} bytes")

recv(socket, buf_size) → table

Blocks until a datagram arrives and returns a table with data (string) and addr (source address string).

Blocks until a datagram arrives and returns a table with data (string) and addr (source address string). The buf_size argument sets the maximum number of bytes to read.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:9000")
let msg = sock.recv(1024)
print("From {msg["addr"]}: {msg["data"]}")

local_addr(socket) → string

Returns the local address the socket is bound to, e.g.

Returns the local address the socket is bound to, e.g. "0.0.0.0:9000".

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
print(sock.local_addr())

set_nonblocking(socket, nonblocking) → nil

Switches the socket between blocking (default) and non-blocking mode.

Switches the socket between blocking (default) and non-blocking mode. In non-blocking mode, recv returns immediately if no data is available.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:9000")
sock.set_nonblocking(true)

set_broadcast(socket, broadcast) → nil

Enables or disables the SO_BROADCAST socket option, required before sending to broadcast addresses like 255.255.255.255.

Enables or disables the SO_BROADCAST socket option, required before sending to broadcast addresses like 255.255.255.255.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
sock.set_broadcast(true)
sock.send_to("ping", "255.255.255.255:9001")

set_read_timeout(socket, timeout_ms) → nil

Sets a read timeout in milliseconds.

Sets a read timeout in milliseconds. Pass 0 or a negative value to remove the timeout (blocking forever). After the timeout elapses, recv will return an error.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:9000")
sock.set_read_timeout(5000)

set_write_timeout(socket, timeout_ms) → nil

Sets a write timeout in milliseconds.

Sets a write timeout in milliseconds. Pass 0 or a negative value to clear the timeout.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
sock.set_write_timeout(3000)

connect(socket, addr) → nil

Associates a default remote address with the socket.

Associates a default remote address with the socket. After calling this, you can use send and recv without specifying an address each time.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
sock.connect("127.0.0.1:9000")
sock.send("ping")

send(socket, data) → int

Sends data to the address previously set with connect.

Sends data to the address previously set with connect. Returns the number of bytes sent.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
sock.connect("127.0.0.1:9000")
let n = sock.send("hello world")
print("Sent {n} bytes")

peek(socket, buf_size) → table

Reads up to buf_size bytes without removing the datagram from the queue.

Reads up to buf_size bytes without removing the datagram from the queue. Returns the same #{"data": ..., "addr": ...} table as recv.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:9000")
let preview = sock.peek(64)
print("Peek from {preview["addr"]}: {preview["data"]}")

set_ttl(socket, ttl) → nil

Sets the IP Time-To-Live (hop count) for outgoing packets.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
sock.set_ttl(64)

ttl(socket) → int

Returns the current IP TTL value set on the socket.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
print("TTL: {sock.ttl()}")

View source code