use "collections"
use @pony_os_listen_udp[AsioEventID](owner: AsioEventNotify,
host: Pointer[U8] tag, service: Pointer[U8] tag)
use @pony_os_listen_udp4[AsioEventID](owner: AsioEventNotify,
host: Pointer[U8] tag, service: Pointer[U8] tag)
use @pony_os_listen_udp6[AsioEventID](owner: AsioEventNotify,
host: Pointer[U8] tag, service: Pointer[U8] tag)
use @pony_os_sendto[U8](fd: U32, buffer: Pointer[U8] tag,
size: USize, to: NetAddress tag, count_out: Pointer[USize])
use @pony_os_recvfrom[U8](event: AsioEventID, buffer: Pointer[U8] tag,
size: USize, from: NetAddress tag, count_out: Pointer[USize])
use @pony_os_multicast_join[None](fd: U32, group: Pointer[U8] tag,
to: Pointer[U8] tag)
use @pony_os_multicast_leave[None](fd: U32, group: Pointer[U8] tag,
to: Pointer[U8] tag)
use @pony_os_multicast_interface[None](fd: U32, from: Pointer[U8] tag)
actor UDPSocket is AsioEventNotify
"""
Creates a UDP socket that can be used for sending and receiving UDP messages.
The following examples create:
* an echo server that listens for connections and returns whatever message it
receives
* a client that connects to the server, sends a message, and prints the
message it receives in response
The server is implemented like this:
```pony
use "net"
class MyUDPNotify is UDPNotify
fun ref received(
sock: UDPSocket ref,
data: Array[U8] iso,
from: NetAddress)
=>
sock.write(consume data, from)
fun ref not_listening(sock: UDPSocket ref) =>
None
actor Main
new create(env: Env) =>
UDPSocket(UDPAuth(env.root),
MyUDPNotify, "", "8989")
```
The client is implemented like this:
```pony
use "net"
class MyUDPNotify is UDPNotify
let _out: OutStream
let _destination: NetAddress
new create(
out: OutStream,
destination: NetAddress)
=>
_out = out
_destination = destination
fun ref listening(sock: UDPSocket ref) =>
sock.write("hello world", _destination)
fun ref received(
sock: UDPSocket ref,
data: Array[U8] iso,
from: NetAddress)
=>
_out.print("GOT:" + String.from_array(consume data))
sock.dispose()
fun ref not_listening(sock: UDPSocket ref) =>
None
actor Main
new create(env: Env) =>
try
let destination =
DNS.ip4(DNSAuth(env.root), "localhost", "8989")(0)?
UDPSocket(UDPAuth(env.root),
recover MyUDPNotify(env.out, consume destination) end)
end
```
"""
var _notify: UDPNotify
var _fd: U32
var _event: AsioEventID
var _readable: Bool = false
var _closed: Bool = false
var _packet_size: USize
var _read_buf: Array[U8] iso
embed _ip: NetAddress = NetAddress
new create(
auth: UDPAuth,
notify: UDPNotify iso,
host: String = "",
service: String = "0",
size: USize = 1024)
=>
"""
Listens for datagrams. The address family is whichever the resolver
returns first for `host`/`service`, so it depends on the environment;
use `ip4` or `ip6` to pin a specific family.
`size` is the read buffer size in bytes (default 1024) and therefore the
maximum datagram length delivered to `UDPNotify.received`; a larger datagram
is truncated to `size` and the excess is silently discarded (see
`UDPNotify.received`). A `size` of 0 is raised to 1, so an empty delivery to
`received` always means an empty datagram, never a dropped one.
"""
_notify = consume notify
_event =
@pony_os_listen_udp(this, host.cstring(), service.cstring())
_fd = @pony_asio_event_fd(_event)
@pony_os_sockname(_fd, _ip)
_packet_size = size.max(1)
_read_buf = recover Array[U8] .> undefined(_packet_size) end
_notify_listening()
new ip4(
auth: UDPAuth,
notify: UDPNotify iso,
host: String = "",
service: String = "0",
size: USize = 1024)
=>
"""
Listens for IPv4 datagrams.
`size` is the read buffer size in bytes (default 1024) and therefore the
maximum datagram length delivered to `UDPNotify.received`; a larger datagram
is truncated to `size` and the excess is silently discarded (see
`UDPNotify.received`). A `size` of 0 is raised to 1, so an empty delivery to
`received` always means an empty datagram, never a dropped one.
"""
_notify = consume notify
_event =
@pony_os_listen_udp4(this, host.cstring(), service.cstring())
_fd = @pony_asio_event_fd(_event)
@pony_os_sockname(_fd, _ip)
_packet_size = size.max(1)
_read_buf = recover Array[U8] .> undefined(_packet_size) end
_notify_listening()
new ip6(
auth: UDPAuth,
notify: UDPNotify iso,
host: String = "",
service: String = "0",
size: USize = 1024)
=>
"""
Listens for IPv6 datagrams.
`size` is the read buffer size in bytes (default 1024) and therefore the
maximum datagram length delivered to `UDPNotify.received`; a larger datagram
is truncated to `size` and the excess is silently discarded (see
`UDPNotify.received`). A `size` of 0 is raised to 1, so an empty delivery to
`received` always means an empty datagram, never a dropped one.
"""
_notify = consume notify
_event =
@pony_os_listen_udp6(this, host.cstring(), service.cstring())
_fd = @pony_asio_event_fd(_event)
@pony_os_sockname(_fd, _ip)
_packet_size = size.max(1)
_read_buf = recover Array[U8] .> undefined(_packet_size) end
_notify_listening()
be write(data: ByteSeq, to: NetAddress) =>
"""
Write a single sequence of bytes.
"""
_write(data, to)
be writev(data: ByteSeqIter, to: NetAddress) =>
"""
Write a sequence of byte sequences. Each `ByteSeq` in `data` is sent
as a separate UDP datagram; this method does not combine them into a
single packet.
Note that this differs from the POSIX `writev` system call, which
for record-based protocols like UDP would produce a single datagram.
If you need a single datagram, concatenate the data yourself and call
`write`.
"""
for bytes in data.values() do
_write(bytes, to)
end
be set_notify(notify: UDPNotify iso) =>
"""
Change the notifier.
"""
_notify = consume notify
be set_broadcast(state: Bool) =>
"""
Enable or disable broadcasting from this socket. This sets the
`SO_BROADCAST` socket option, a sender-side permission to send to
IPv4 broadcast addresses (see `DNS.broadcast_ip4`).
On an IPv6 socket this is a no-op: IPv6 has no broadcast. Sending to
a multicast address such as the all-nodes group (see
`DNS.broadcast_ip6`) requires no permission; to receive traffic for
a multicast group, use `multicast_join`.
The default constructor binds whichever address family the resolver
returns first, so construct the socket with `ip4` if you need
broadcast; otherwise `set_broadcast` may silently be a no-op.
"""
if not _closed then
if _ip.ip4() then
set_so_broadcast(state)
end
end
be set_multicast_interface(from: String = "") =>
"""
By default, the OS will choose which address is used to send packets bound
for multicast addresses. This can be used to force a specific interface.
For an IPv4 interface, pass the interface's IPv4 address. For an IPv6
interface, the interface is taken from the scope id of the resolved
address, so only a scoped address such as `"fe80::1%eth0"` selects an
interface; a plain IPv6 address does not.
Calling with an empty string currently has no effect.
"""
if not _closed then
@pony_os_multicast_interface(_fd, from.cstring())
end
be set_multicast_loopback(loopback: Bool) =>
"""
By default, packets sent to a multicast address will be received by the
sending system if it has subscribed to that address. Disabling loopback
prevents this.
"""
if not _closed then
set_ip_multicast_loop(loopback)
end
be set_multicast_ttl(ttl: U8) =>
"""
Set the TTL for multicast sends. Defaults to 1.
"""
if not _closed then
set_ip_multicast_ttl(ttl)
end
be multicast_join(group: String, to: String = "") =>
"""
Add a multicast group. This can be limited to packets arriving on a
specific interface.
"""
if not _closed then
@pony_os_multicast_join(_fd, group.cstring(), to.cstring())
end
be multicast_leave(group: String, to: String = "") =>
"""
Drop a multicast group. This can be limited to packets arriving on a
specific interface. No attempt is made to check that this socket has
previously added this group.
"""
if not _closed then
@pony_os_multicast_leave(_fd, group.cstring(), to.cstring())
end
be dispose() =>
"""
Stop listening.
"""
if not _closed then
_close()
end
fun local_address(): NetAddress =>
"""
Return the bound IP address.
"""
_ip
be _event_notify(event: AsioEventID, flags: U32, arg: U32) =>
"""
When we are readable, we accept new connections until none remain.
"""
if event isnt _event then
return
end
if not _closed then
if AsioEvent.errored(flags) then
_close()
return
end
if AsioEvent.readable(flags) then
_readable = true
_pending_reads()
end
end
if AsioEvent.disposable(flags) then
@pony_asio_event_destroy(_event)
_event = AsioEvent.none()
end
be _read_again() =>
"""
Resume reading.
"""
if not _closed then
_pending_reads()
end
fun ref _pending_reads() =>
"""
Read while data is available, guessing the next packet length as we go.
Once about 4 kb of read work accumulates, send ourself a resume message and
stop reading, to avoid starving other actors. A zero-byte datagram counts
as 1 byte of work so a flood of empty datagrams cannot loop here forever.
"""
try
var sum: USize = 0
while _readable do
let size = _packet_size
let data = _read_buf = recover Array[U8] .> undefined(size) end
let from = recover NetAddress end
var count: USize = 0
match \exhaustive\ _SocketResultDecoder(
@pony_os_recvfrom(_event, data.cpointer(), data.space(),
from, addressof count))
| _SocketResultOk =>
data.truncate(count)
_notify.received(this, consume data, consume from)
// An empty datagram is delivered as OK with count 0; charge it 1
// byte so a flood still advances the read budget and yields.
sum = sum + count.max(1)
if sum > (1 << 12) then
_read_again()
return
end
| _SocketResultRetry =>
_readable = false
return
| _SocketResultError => error
end
end
else
_close()
end
fun ref _write(data: ByteSeq, to: NetAddress) =>
"""
Write the datagram to the socket.
"""
if not _closed then
// `count` (bytes sent on Ok) is discarded: UDP is unreliable, so we
// don't track partial-send progress. The local is required by the FFI
// shape. `_SocketResultRetry` (EWOULDBLOCK/EAGAIN) silently drops the
// datagram on every platform. A send Error closes the socket.
var count: USize = 0
match \exhaustive\ _SocketResultDecoder(
@pony_os_sendto(_fd, data.cpointer(), data.size(), to,
addressof count))
| _SocketResultOk => None
| _SocketResultRetry => None
| _SocketResultError => _close()
end
end
fun ref _notify_listening() =>
"""
Inform the notifier that we're listening.
"""
if _fd != -1 then
_notify.listening(this)
else
_notify.not_listening(this)
end
fun ref _close() =>
"""
Inform the notifier that we've closed.
"""
// Unsubscribe immediately. On Windows this issues a ProcessSocketNotifications
// REMOVE; the backend closes the fd and disposes the event once the REMOVE
// is seen. The `is_null` guard tolerates a failed listen (issue #5474),
// which leaves a null event.
if not _event.is_null() then
@pony_asio_event_unsubscribe(_event)
_readable = false
end
_closed = true
if _fd != -1 then
_notify.closed(this)
// POSIX closes the fd here; on Windows the readiness backend owns the
// close (when it sees the deferred REMOVE from the unsubscribe above).
ifdef not windows then
@pony_os_socket_close(_fd)
end
_fd = -1
end
fun ref getsockopt(level: I32, option_name: I32, option_max_size: USize = 4): (U32, Array[U8] iso^) =>
"""
General wrapper for UDP sockets to the `getsockopt(2)` system call.
The caller must provide an array that is pre-allocated to be
at least as large as the largest data structure that the kernel
may return for the requested option.
In case of system call success, this function returns the 2-tuple:
1. The integer `0`.
2. An `Array[U8]` of data returned by the system call's `void *`
4th argument. Its size is specified by the kernel via the
system call's `sockopt_len_t *` 5th argument.
In case of system call failure, this function returns the 2-tuple:
1. The value of `errno`.
2. An undefined value that must be ignored.
Usage example:
```pony
// listening() is a callback function for class UDPNotify
fun ref listening(sock: UDPSocket ref) =>
match sock.getsockopt(OSSockOpt.sol_socket(), OSSockOpt.so_rcvbuf(), 4)
| (0, let gbytes: Array[U8] iso) =>
try
let br = Reader.create().>append(consume gbytes)
ifdef littleendian then
let buffer_size = br.u32_le()?
else
let buffer_size = br.u32_be()?
end
end
| (let errno: U32, _) =>
// System call failed
end
```
"""
_OSSocket.getsockopt(_fd, level, option_name, option_max_size)
fun ref getsockopt_u32(level: I32, option_name: I32): (U32, U32) =>
"""
Wrapper for UDP sockets to the `getsockopt(2)` system call where
the kernel's returned option value is a C `uint32_t` type / Pony
type `U32`.
In case of system call success, this function returns the 2-tuple:
1. The integer `0`.
2. The `*option_value` returned by the kernel converted to a Pony `U32`.
In case of system call failure, this function returns the 2-tuple:
1. The value of `errno`.
2. An undefined value that must be ignored.
"""
_OSSocket.getsockopt_u32(_fd, level, option_name)
fun ref setsockopt(level: I32, option_name: I32, option: Array[U8]): U32 =>
"""
General wrapper for UDP sockets to the `setsockopt(2)` system call.
The caller is responsible for the correct size and byte contents of
the `option` array for the requested `level` and `option_name`,
including using the appropriate CPU endian byte order.
This function returns `0` on success, else the value of `errno` on
failure.
Usage example:
```pony
// listening() is a callback function for class UDPNotify
fun ref listening(sock: UDPSocket ref) =>
let sb = Writer
sb.u32_le(7744) // Our desired socket buffer size
let sbytes = Array[U8]
for bs in sb.done().values() do
sbytes.append(bs)
end
match sock.setsockopt(OSSockOpt.sol_socket(), OSSockOpt.so_rcvbuf(), sbytes)
| 0 =>
// System call was successful
| let errno: U32 =>
// System call failed
end
```
"""
_OSSocket.setsockopt(_fd, level, option_name, option)
fun ref setsockopt_u32(level: I32, option_name: I32, option: U32): U32 =>
"""
Wrapper for UDP sockets to the `setsockopt(2)` system call where
the kernel expects an option value of a C `uint32_t` type / Pony
type `U32`.
This function returns `0` on success, else the value of `errno` on
failure.
"""
_OSSocket.setsockopt_u32(_fd, level, option_name, option)
fun ref get_so_error(): (U32, U32) =>
"""
Wrapper for the FFI call `getsockopt(fd, SOL_SOCKET, SO_ERROR, ...)`
"""
_OSSocket.get_so_error(_fd)
fun ref get_so_rcvbuf(): (U32, U32) =>
"""
Wrapper for the FFI call `getsockopt(fd, SOL_SOCKET, SO_RCVBUF, ...)`
"""
_OSSocket.get_so_rcvbuf(_fd)
fun ref get_so_sndbuf(): (U32, U32) =>
"""
Wrapper for the FFI call `getsockopt(fd, SOL_SOCKET, SO_SNDBUF, ...)`
"""
_OSSocket.get_so_sndbuf(_fd)
fun ref set_ip_multicast_loop(loopback: Bool): U32 =>
"""
Wrapper for the FFI call `setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, ...)`
"""
var word: Array[U8] ref =
_OSSocket.u32_to_bytes4(if loopback then 1 else 0 end)
_OSSocket.setsockopt(_fd, OSSockOpt.ipproto_ip(), OSSockOpt.ip_multicast_loop(), word)
fun ref set_ip_multicast_ttl(ttl: U8): U32 =>
"""
Wrapper for the FFI call `setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, ...)`
"""
var word: Array[U8] ref = _OSSocket.u32_to_bytes4(ttl.u32())
_OSSocket.setsockopt(_fd, OSSockOpt.ipproto_ip(), OSSockOpt.ip_multicast_ttl(), word)
fun ref set_so_broadcast(state: Bool): U32 =>
"""
Wrapper for the FFI call `setsockopt(fd, SOL_SOCKET, SO_BROADCAST, ...)`
"""
var word: Array[U8] ref =
_OSSocket.u32_to_bytes4(if state then 1 else 0 end)
_OSSocket.setsockopt(_fd, OSSockOpt.sol_socket(), OSSockOpt.so_broadcast(), word)
fun ref set_so_rcvbuf(bufsize: U32): U32 =>
"""
Wrapper for the FFI call `setsockopt(fd, SOL_SOCKET, SO_RCVBUF, ...)`
"""
_OSSocket.set_so_rcvbuf(_fd, bufsize)
fun ref set_so_sndbuf(bufsize: U32): U32 =>
"""
Wrapper for the FFI call `setsockopt(fd, SOL_SOCKET, SO_SNDBUF, ...)`
"""
_OSSocket.set_so_sndbuf(_fd, bufsize)