/
socket.cr
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socket.cr
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require "c/arpa/inet"
require "c/netdb"
require "c/netinet/in"
require "c/netinet/tcp"
require "c/sys/socket"
require "c/sys/un"
require "io/evented"
class Socket < IO
include IO::Buffered
include IO::Evented
class Error < Exception
end
enum Type
STREAM = LibC::SOCK_STREAM
DGRAM = LibC::SOCK_DGRAM
RAW = LibC::SOCK_RAW
SEQPACKET = LibC::SOCK_SEQPACKET
end
enum Protocol
IP = LibC::IPPROTO_IP
TCP = LibC::IPPROTO_TCP
UDP = LibC::IPPROTO_UDP
RAW = LibC::IPPROTO_RAW
ICMP = LibC::IPPROTO_ICMP
end
enum Family : LibC::SaFamilyT
UNSPEC = LibC::AF_UNSPEC
UNIX = LibC::AF_UNIX
INET = LibC::AF_INET
INET6 = LibC::AF_INET6
end
# :nodoc:
SOMAXCONN = 128
getter fd : Int32
@closed : Bool
getter family : Family
getter type : Type
getter protocol : Protocol
# Creates a TCP socket. Consider using `TCPSocket` or `TCPServer` unless you
# need full control over the socket.
def self.tcp(family : Family, blocking = false)
new(family, Type::STREAM, Protocol::TCP, blocking)
end
# Creates an UDP socket. Consider using `UDPSocket` unless you need full
# control over the socket.
def self.udp(family : Family, blocking = false)
new(family, Type::DGRAM, Protocol::UDP, blocking)
end
# Creates an UNIX socket. Consider using `UNIXSocket` or `UNIXServer` unless
# you need full control over the socket.
def self.unix(type : Type = Type::STREAM, blocking = false)
new(Family::UNIX, type, blocking: blocking)
end
def initialize(@family, @type, @protocol = Protocol::IP, blocking = false)
@closed = false
fd = LibC.socket(family, type, protocol)
raise Errno.new("failed to create socket:") if fd == -1
init_close_on_exec(fd)
@fd = fd
self.sync = true
unless blocking
self.blocking = false
end
end
# Creates a Socket from an existing socket file descriptor.
def initialize(@fd : Int32, @family, @type, @protocol = Protocol::IP, blocking = false)
@closed = false
init_close_on_exec(@fd)
self.sync = true
unless blocking
self.blocking = false
end
end
# Forces opened sockets to be closed on `exec(2)`. Only for platforms that don't
# support `SOCK_CLOEXEC` (e.g., Darwin).
protected def init_close_on_exec(fd : Int32)
{% unless LibC.has_constant?(:SOCK_CLOEXEC) %}
LibC.fcntl(fd, LibC::F_SETFD, LibC::FD_CLOEXEC)
{% end %}
end
# Connects the socket to a remote host:port.
#
# ```
# require "socket"
#
# sock = Socket.tcp(Socket::Family::INET)
# sock.connect "crystal-lang.org", 80
# ```
def connect(host : String, port : Int, connect_timeout = nil)
Addrinfo.resolve(host, port, @family, @type, @protocol) do |addrinfo|
connect(addrinfo, timeout: connect_timeout) { |error| error }
end
end
# Connects the socket to a remote address. Raises if the connection failed.
#
# ```
# require "socket"
#
# sock = Socket.unix
# sock.connect Socket::UNIXAddress.new("/tmp/service.sock")
# ```
def connect(addr, timeout = nil) : Nil
connect(addr, timeout) { |error| raise error }
end
# Tries to connect to a remote address. Yields an `IO::Timeout` or an
# `Errno` error if the connection failed.
def connect(addr, timeout = nil)
timeout = timeout.seconds unless timeout.is_a? Time::Span | Nil
loop do
if LibC.connect(fd, addr, addr.size) == 0
return
end
case Errno.value
when Errno::EISCONN
return
when Errno::EINPROGRESS, Errno::EALREADY
wait_writable(timeout: timeout) do |error|
return yield IO::Timeout.new("connect timed out")
end
else
return yield Errno.new("connect")
end
end
end
# Binds the socket to a local address.
#
# ```
# require "socket"
#
# sock = Socket.tcp(Socket::Family::INET)
# sock.bind "localhost", 1234
# ```
def bind(host : String, port : Int)
Addrinfo.resolve(host, port, @family, @type, @protocol) do |addrinfo|
bind(addrinfo) { |errno| errno }
end
end
# Binds the socket on *port* to all local interfaces.
#
# ```
# require "socket"
#
# sock = Socket.tcp(Socket::Family::INET6)
# sock.bind 1234
# ```
def bind(port : Int)
Addrinfo.resolve("::", port, @family, @type, @protocol) do |addrinfo|
bind(addrinfo) { |errno| errno }
end
end
# Binds the socket to a local address.
#
# ```
# require "socket"
#
# sock = Socket.udp(Socket::Family::INET)
# sock.bind Socket::IPAddress.new("192.168.1.25", 80)
# ```
def bind(addr)
bind(addr) { |errno| raise errno }
end
# Tries to bind the socket to a local address.
# Yields an `Errno` if the binding failed.
def bind(addr)
unless LibC.bind(fd, addr, addr.size) == 0
yield Errno.new("bind")
end
end
# Tells the previously bound socket to listen for incoming connections.
def listen(backlog : Int = SOMAXCONN)
listen(backlog) { |errno| raise errno }
end
# Tries to listen for connections on the previously bound socket.
# Yields an `Errno` on failure.
def listen(backlog : Int = SOMAXCONN)
unless LibC.listen(fd, backlog) == 0
yield Errno.new("listen")
end
end
# Accepts an incoming connection.
#
# Returns the client socket. Raises an `IO::Error` (closed stream) exception
# if the server is closed after invoking this method.
#
# ```
# require "socket"
#
# server = TCPServer.new(2202)
# socket = server.accept
# socket.puts Time.utc
# socket.close
# ```
def accept : Socket
accept? || raise IO::Error.new("Closed stream")
end
# Accepts an incoming connection.
#
# Returns the client `Socket` or `nil` if the server is closed after invoking
# this method.
#
# ```
# require "socket"
#
# server = TCPServer.new(2202)
# if socket = server.accept?
# socket.puts Time.utc
# socket.close
# end
# ```
def accept?
if client_fd = accept_impl
sock = Socket.new(client_fd, family, type, protocol, blocking)
sock.sync = sync?
sock
end
end
protected def accept_impl
loop do
client_fd = LibC.accept(fd, nil, nil)
if client_fd == -1
if closed?
return
elsif Errno.value == Errno::EAGAIN
wait_readable
else
raise Errno.new("accept")
end
else
return client_fd
end
end
end
# Sends a message to a previously connected remote address.
#
# ```
# require "socket"
#
# sock = Socket.udp(Socket::Family::INET)
# sock.connect("example.com", 2000)
# sock.send("text message")
#
# sock = Socket.unix(Socket::Type::DGRAM)
# sock.connect Socket::UNIXAddress.new("/tmp/service.sock")
# sock.send(Bytes[0])
# ```
def send(message) : Int32
evented_send(message.to_slice, "Error sending datagram") do |slice|
LibC.send(fd, slice.to_unsafe.as(Void*), slice.size, 0)
end
end
# Sends a message to the specified remote address.
#
# ```
# require "socket"
#
# server = Socket::IPAddress.new("10.0.3.1", 2022)
# sock = Socket.udp(Socket::Family::INET)
# sock.connect("example.com", 2000)
# sock.send("text query", to: server)
# ```
def send(message, to addr : Address) : Int32
slice = message.to_slice
bytes_sent = LibC.sendto(fd, slice.to_unsafe.as(Void*), slice.size, 0, addr, addr.size)
raise Errno.new("Error sending datagram to #{addr}") if bytes_sent == -1
# to_i32 is fine because string/slice sizes are an Int32
bytes_sent.to_i32
end
# Receives a text message from the previously bound address.
#
# ```
# require "socket"
#
# server = Socket.udp(Socket::Family::INET)
# server.bind("localhost", 1234)
#
# message, client_addr = server.receive
# ```
def receive(max_message_size = 512) : {String, Address}
address = nil
message = String.new(max_message_size) do |buffer|
bytes_read, sockaddr, addrlen = recvfrom(Slice.new(buffer, max_message_size))
address = Address.from(sockaddr, addrlen)
{bytes_read, 0}
end
{message, address.not_nil!}
end
# Receives a binary message from the previously bound address.
#
# ```
# require "socket"
#
# server = Socket.udp(Socket::Family::INET)
# server.bind("localhost", 1234)
#
# message = Bytes.new(32)
# bytes_read, client_addr = server.receive(message)
# ```
def receive(message : Bytes) : {Int32, Address}
bytes_read, sockaddr, addrlen = recvfrom(message)
{bytes_read, Address.from(sockaddr, addrlen)}
end
protected def recvfrom(bytes)
sockaddr = Pointer(LibC::SockaddrStorage).malloc.as(LibC::Sockaddr*)
addrlen = LibC::SocklenT.new(sizeof(LibC::SockaddrStorage))
bytes_read = evented_read(bytes, "Error receiving datagram") do |slice|
LibC.recvfrom(fd, slice.to_unsafe.as(Void*), slice.size, 0, sockaddr, pointerof(addrlen))
end
{bytes_read, sockaddr, addrlen}
end
# Calls `shutdown(2)` with `SHUT_RD`
def close_read
shutdown LibC::SHUT_RD
end
# Calls `shutdown(2)` with `SHUT_WR`
def close_write
shutdown LibC::SHUT_WR
end
private def shutdown(how)
if LibC.shutdown(@fd, how) != 0
raise Errno.new("shutdown #{how}")
end
end
def inspect(io : IO) : Nil
io << "#<#{self.class}:fd #{@fd}>"
end
def send_buffer_size
getsockopt LibC::SO_SNDBUF, 0
end
def send_buffer_size=(val : Int32)
setsockopt LibC::SO_SNDBUF, val
val
end
def recv_buffer_size
getsockopt LibC::SO_RCVBUF, 0
end
def recv_buffer_size=(val : Int32)
setsockopt LibC::SO_RCVBUF, val
val
end
def reuse_address?
getsockopt_bool LibC::SO_REUSEADDR
end
def reuse_address=(val : Bool)
setsockopt_bool LibC::SO_REUSEADDR, val
end
def reuse_port?
ret = getsockopt(LibC::SO_REUSEPORT, 0) do |errno|
# If SO_REUSEPORT is not supported, the return value should be `false`
if errno.errno == Errno::ENOPROTOOPT
return false
else
raise errno
end
end
ret != 0
end
def reuse_port=(val : Bool)
setsockopt_bool LibC::SO_REUSEPORT, val
end
def broadcast?
getsockopt_bool LibC::SO_BROADCAST
end
def broadcast=(val : Bool)
setsockopt_bool LibC::SO_BROADCAST, val
end
def keepalive?
getsockopt_bool LibC::SO_KEEPALIVE
end
def keepalive=(val : Bool)
setsockopt_bool LibC::SO_KEEPALIVE, val
end
def linger
v = LibC::Linger.new
ret = getsockopt LibC::SO_LINGER, v
ret.l_onoff == 0 ? nil : ret.l_linger
end
# WARNING: The behavior of `SO_LINGER` is platform specific.
# Bad things may happen especially with nonblocking sockets.
# See [Cross-Platform Testing of SO_LINGER by Nybek](https://www.nybek.com/blog/2015/04/29/so_linger-on-non-blocking-sockets/)
# for more information.
#
# * `nil`: disable `SO_LINGER`
# * `Int`: enable `SO_LINGER` and set timeout to `Int` seconds
# * `0`: abort on close (socket buffer is discarded and RST sent to peer). Depends on platform and whether `shutdown()` was called first.
# * `>=1`: abort after `Int` seconds on close. Linux and Cygwin may block on close.
def linger=(val : Int?)
v = LibC::Linger.new
case val
when Int
v.l_onoff = 1
v.l_linger = val
when nil
v.l_onoff = 0
end
setsockopt LibC::SO_LINGER, v
val
end
# Returns the modified *optval*.
def getsockopt(optname, optval, level = LibC::SOL_SOCKET)
getsockopt(optname, optval, level) { |errno| raise errno }
end
protected def getsockopt(optname, optval, level = LibC::SOL_SOCKET)
optsize = LibC::SocklenT.new(sizeof(typeof(optval)))
ret = LibC.getsockopt(fd, level, optname, (pointerof(optval).as(Void*)), pointerof(optsize))
yield Errno.new("getsockopt") if ret == -1
optval
end
# NOTE: *optval* is restricted to `Int32` until sizeof works on variables.
def setsockopt(optname, optval, level = LibC::SOL_SOCKET)
optsize = LibC::SocklenT.new(sizeof(typeof(optval)))
ret = LibC.setsockopt(fd, level, optname, (pointerof(optval).as(Void*)), optsize)
raise Errno.new("setsockopt") if ret == -1
ret
end
private def getsockopt_bool(optname, level = LibC::SOL_SOCKET)
ret = getsockopt optname, 0, level
ret != 0
end
private def setsockopt_bool(optname, optval : Bool, level = LibC::SOL_SOCKET)
v = optval ? 1 : 0
ret = setsockopt optname, v, level
optval
end
# Returns `true` if the string represents a valid IPv4 or IPv6 address.
def self.ip?(string : String)
addr = LibC::In6Addr.new
ptr = pointerof(addr).as(Void*)
LibC.inet_pton(LibC::AF_INET, string, ptr) > 0 || LibC.inet_pton(LibC::AF_INET6, string, ptr) > 0
end
def blocking
fcntl(LibC::F_GETFL) & LibC::O_NONBLOCK == 0
end
def blocking=(value)
flags = fcntl(LibC::F_GETFL)
if value
flags &= ~LibC::O_NONBLOCK
else
flags |= LibC::O_NONBLOCK
end
fcntl(LibC::F_SETFL, flags)
end
def close_on_exec?
flags = fcntl(LibC::F_GETFD)
(flags & LibC::FD_CLOEXEC) == LibC::FD_CLOEXEC
end
def close_on_exec=(arg : Bool)
fcntl(LibC::F_SETFD, arg ? LibC::FD_CLOEXEC : 0)
arg
end
def self.fcntl(fd, cmd, arg = 0)
r = LibC.fcntl fd, cmd, arg
raise Errno.new("fcntl() failed") if r == -1
r
end
def fcntl(cmd, arg = 0)
self.class.fcntl @fd, cmd, arg
end
def finalize
return if closed?
close rescue nil
end
def closed?
@closed
end
def tty?
LibC.isatty(fd) == 1
end
private def unbuffered_read(slice : Bytes)
evented_read(slice, "Error reading socket") do
LibC.recv(@fd, slice, slice.size, 0).to_i32
end
end
private def unbuffered_write(slice : Bytes)
evented_write(slice, "Error writing to socket") do |slice|
LibC.send(@fd, slice, slice.size, 0)
end
end
private def unbuffered_rewind
raise IO::Error.new("Can't rewind")
end
private def unbuffered_close
return if @closed
err = nil
if LibC.close(@fd) != 0
case Errno.value
when Errno::EINTR, Errno::EINPROGRESS
# ignore
else
err = Errno.new("Error closing socket")
end
end
@closed = true
evented_close
raise err if err
end
private def unbuffered_flush
# Nothing
end
end
require "./socket/*"