Path: blob/main/crates/wasi-http/wit/deps/sockets/tcp.wit
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@since(version = 0.2.0)
interface tcp {
@since(version = 0.2.0)
use wasi:io/[email protected].{input-stream, output-stream};
@since(version = 0.2.0)
use wasi:io/[email protected].{pollable};
@since(version = 0.2.0)
use wasi:clocks/[email protected].{duration};
@since(version = 0.2.0)
use network.{network, error-code, ip-socket-address, ip-address-family};
@since(version = 0.2.0)
enum shutdown-type {
/// Similar to `SHUT_RD` in POSIX.
receive,
/// Similar to `SHUT_WR` in POSIX.
send,
/// Similar to `SHUT_RDWR` in POSIX.
both,
}
/// A TCP socket resource.
///
/// The socket can be in one of the following states:
/// - `unbound`
/// - `bind-in-progress`
/// - `bound` (See note below)
/// - `listen-in-progress`
/// - `listening`
/// - `connect-in-progress`
/// - `connected`
/// - `closed`
/// See <https://github.com/WebAssembly/wasi-sockets/blob/main/TcpSocketOperationalSemantics.md>
/// for more information.
///
/// Note: Except where explicitly mentioned, whenever this documentation uses
/// the term "bound" without backticks it actually means: in the `bound` state *or higher*.
/// (i.e. `bound`, `listen-in-progress`, `listening`, `connect-in-progress` or `connected`)
///
/// In addition to the general error codes documented on the
/// `network::error-code` type, TCP socket methods may always return
/// `error(invalid-state)` when in the `closed` state.
@since(version = 0.2.0)
resource tcp-socket {
/// Bind the socket to a specific network on the provided IP address and port.
///
/// If the IP address is zero (`0.0.0.0` in IPv4, `::` in IPv6), it is left to the implementation to decide which
/// network interface(s) to bind to.
/// If the TCP/UDP port is zero, the socket will be bound to a random free port.
///
/// Bind can be attempted multiple times on the same socket, even with
/// different arguments on each iteration. But never concurrently and
/// only as long as the previous bind failed. Once a bind succeeds, the
/// binding can't be changed anymore.
///
/// # Typical errors
/// - `invalid-argument`: The `local-address` has the wrong address family. (EAFNOSUPPORT, EFAULT on Windows)
/// - `invalid-argument`: `local-address` is not a unicast address. (EINVAL)
/// - `invalid-argument`: `local-address` is an IPv4-mapped IPv6 address. (EINVAL)
/// - `invalid-state`: The socket is already bound. (EINVAL)
/// - `address-in-use`: No ephemeral ports available. (EADDRINUSE, ENOBUFS on Windows)
/// - `address-in-use`: Address is already in use. (EADDRINUSE)
/// - `address-not-bindable`: `local-address` is not an address that the `network` can bind to. (EADDRNOTAVAIL)
/// - `not-in-progress`: A `bind` operation is not in progress.
/// - `would-block`: Can't finish the operation, it is still in progress. (EWOULDBLOCK, EAGAIN)
///
/// # Implementors note
/// When binding to a non-zero port, this bind operation shouldn't be affected by the TIME_WAIT
/// state of a recently closed socket on the same local address. In practice this means that the SO_REUSEADDR
/// socket option should be set implicitly on all platforms, except on Windows where this is the default behavior
/// and SO_REUSEADDR performs something different entirely.
///
/// Unlike in POSIX, in WASI the bind operation is async. This enables
/// interactive WASI hosts to inject permission prompts. Runtimes that
/// don't want to make use of this ability can simply call the native
/// `bind` as part of either `start-bind` or `finish-bind`.
///
/// # References
/// - <https://pubs.opengroup.org/onlinepubs/9699919799/functions/bind.html>
/// - <https://man7.org/linux/man-pages/man2/bind.2.html>
/// - <https://learn.microsoft.com/en-us/windows/win32/api/winsock/nf-winsock-bind>
/// - <https://man.freebsd.org/cgi/man.cgi?query=bind&sektion=2&format=html>
@since(version = 0.2.0)
start-bind: func(network: borrow<network>, local-address: ip-socket-address) -> result<_, error-code>;
@since(version = 0.2.0)
finish-bind: func() -> result<_, error-code>;
/// Connect to a remote endpoint.
///
/// On success:
/// - the socket is transitioned into the `connected` state.
/// - a pair of streams is returned that can be used to read & write to the connection
///
/// After a failed connection attempt, the socket will be in the `closed`
/// state and the only valid action left is to `drop` the socket. A single
/// socket can not be used to connect more than once.
///
/// # Typical errors
/// - `invalid-argument`: The `remote-address` has the wrong address family. (EAFNOSUPPORT)
/// - `invalid-argument`: `remote-address` is not a unicast address. (EINVAL, ENETUNREACH on Linux, EAFNOSUPPORT on MacOS)
/// - `invalid-argument`: `remote-address` is an IPv4-mapped IPv6 address. (EINVAL, EADDRNOTAVAIL on Illumos)
/// - `invalid-argument`: The IP address in `remote-address` is set to INADDR_ANY (`0.0.0.0` / `::`). (EADDRNOTAVAIL on Windows)
/// - `invalid-argument`: The port in `remote-address` is set to 0. (EADDRNOTAVAIL on Windows)
/// - `invalid-argument`: The socket is already attached to a different network. The `network` passed to `connect` must be identical to the one passed to `bind`.
/// - `invalid-state`: The socket is already in the `connected` state. (EISCONN)
/// - `invalid-state`: The socket is already in the `listening` state. (EOPNOTSUPP, EINVAL on Windows)
/// - `timeout`: Connection timed out. (ETIMEDOUT)
/// - `connection-refused`: The connection was forcefully rejected. (ECONNREFUSED)
/// - `connection-reset`: The connection was reset. (ECONNRESET)
/// - `connection-aborted`: The connection was aborted. (ECONNABORTED)
/// - `remote-unreachable`: The remote address is not reachable. (EHOSTUNREACH, EHOSTDOWN, ENETUNREACH, ENETDOWN, ENONET)
/// - `address-in-use`: Tried to perform an implicit bind, but there were no ephemeral ports available. (EADDRINUSE, EADDRNOTAVAIL on Linux, EAGAIN on BSD)
/// - `not-in-progress`: A connect operation is not in progress.
/// - `would-block`: Can't finish the operation, it is still in progress. (EWOULDBLOCK, EAGAIN)
///
/// # Implementors note
/// The POSIX equivalent of `start-connect` is the regular `connect` syscall.
/// Because all WASI sockets are non-blocking this is expected to return
/// EINPROGRESS, which should be translated to `ok()` in WASI.
///
/// The POSIX equivalent of `finish-connect` is a `poll` for event `POLLOUT`
/// with a timeout of 0 on the socket descriptor. Followed by a check for
/// the `SO_ERROR` socket option, in case the poll signaled readiness.
///
/// # References
/// - <https://pubs.opengroup.org/onlinepubs/9699919799/functions/connect.html>
/// - <https://man7.org/linux/man-pages/man2/connect.2.html>
/// - <https://learn.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-connect>
/// - <https://man.freebsd.org/cgi/man.cgi?connect>
@since(version = 0.2.0)
start-connect: func(network: borrow<network>, remote-address: ip-socket-address) -> result<_, error-code>;
@since(version = 0.2.0)
finish-connect: func() -> result<tuple<input-stream, output-stream>, error-code>;
/// Start listening for new connections.
///
/// Transitions the socket into the `listening` state.
///
/// Unlike POSIX, the socket must already be explicitly bound.
///
/// # Typical errors
/// - `invalid-state`: The socket is not bound to any local address. (EDESTADDRREQ)
/// - `invalid-state`: The socket is already in the `connected` state. (EISCONN, EINVAL on BSD)
/// - `invalid-state`: The socket is already in the `listening` state.
/// - `address-in-use`: Tried to perform an implicit bind, but there were no ephemeral ports available. (EADDRINUSE)
/// - `not-in-progress`: A listen operation is not in progress.
/// - `would-block`: Can't finish the operation, it is still in progress. (EWOULDBLOCK, EAGAIN)
///
/// # Implementors note
/// Unlike in POSIX, in WASI the listen operation is async. This enables
/// interactive WASI hosts to inject permission prompts. Runtimes that
/// don't want to make use of this ability can simply call the native
/// `listen` as part of either `start-listen` or `finish-listen`.
///
/// # References
/// - <https://pubs.opengroup.org/onlinepubs/9699919799/functions/listen.html>
/// - <https://man7.org/linux/man-pages/man2/listen.2.html>
/// - <https://learn.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-listen>
/// - <https://man.freebsd.org/cgi/man.cgi?query=listen&sektion=2>
@since(version = 0.2.0)
start-listen: func() -> result<_, error-code>;
@since(version = 0.2.0)
finish-listen: func() -> result<_, error-code>;
/// Accept a new client socket.
///
/// The returned socket is bound and in the `connected` state. The following properties are inherited from the listener socket:
/// - `address-family`
/// - `keep-alive-enabled`
/// - `keep-alive-idle-time`
/// - `keep-alive-interval`
/// - `keep-alive-count`
/// - `hop-limit`
/// - `receive-buffer-size`
/// - `send-buffer-size`
///
/// On success, this function returns the newly accepted client socket along with
/// a pair of streams that can be used to read & write to the connection.
///
/// # Typical errors
/// - `invalid-state`: Socket is not in the `listening` state. (EINVAL)
/// - `would-block`: No pending connections at the moment. (EWOULDBLOCK, EAGAIN)
/// - `connection-aborted`: An incoming connection was pending, but was terminated by the client before this listener could accept it. (ECONNABORTED)
/// - `new-socket-limit`: The new socket resource could not be created because of a system limit. (EMFILE, ENFILE)
///
/// # References
/// - <https://pubs.opengroup.org/onlinepubs/9699919799/functions/accept.html>
/// - <https://man7.org/linux/man-pages/man2/accept.2.html>
/// - <https://learn.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-accept>
/// - <https://man.freebsd.org/cgi/man.cgi?query=accept&sektion=2>
@since(version = 0.2.0)
accept: func() -> result<tuple<tcp-socket, input-stream, output-stream>, error-code>;
/// Get the bound local address.
///
/// POSIX mentions:
/// > If the socket has not been bound to a local name, the value
/// > stored in the object pointed to by `address` is unspecified.
///
/// WASI is stricter and requires `local-address` to return `invalid-state` when the socket hasn't been bound yet.
///
/// # Typical errors
/// - `invalid-state`: The socket is not bound to any local address.
///
/// # References
/// - <https://pubs.opengroup.org/onlinepubs/9699919799/functions/getsockname.html>
/// - <https://man7.org/linux/man-pages/man2/getsockname.2.html>
/// - <https://learn.microsoft.com/en-us/windows/win32/api/winsock/nf-winsock-getsockname>
/// - <https://man.freebsd.org/cgi/man.cgi?getsockname>
@since(version = 0.2.0)
local-address: func() -> result<ip-socket-address, error-code>;
/// Get the remote address.
///
/// # Typical errors
/// - `invalid-state`: The socket is not connected to a remote address. (ENOTCONN)
///
/// # References
/// - <https://pubs.opengroup.org/onlinepubs/9699919799/functions/getpeername.html>
/// - <https://man7.org/linux/man-pages/man2/getpeername.2.html>
/// - <https://learn.microsoft.com/en-us/windows/win32/api/winsock/nf-winsock-getpeername>
/// - <https://man.freebsd.org/cgi/man.cgi?query=getpeername&sektion=2&n=1>
@since(version = 0.2.0)
remote-address: func() -> result<ip-socket-address, error-code>;
/// Whether the socket is in the `listening` state.
///
/// Equivalent to the SO_ACCEPTCONN socket option.
@since(version = 0.2.0)
is-listening: func() -> bool;
/// Whether this is a IPv4 or IPv6 socket.
///
/// Equivalent to the SO_DOMAIN socket option.
@since(version = 0.2.0)
address-family: func() -> ip-address-family;
/// Hints the desired listen queue size. Implementations are free to ignore this.
///
/// If the provided value is 0, an `invalid-argument` error is returned.
/// Any other value will never cause an error, but it might be silently clamped and/or rounded.
///
/// # Typical errors
/// - `not-supported`: (set) The platform does not support changing the backlog size after the initial listen.
/// - `invalid-argument`: (set) The provided value was 0.
/// - `invalid-state`: (set) The socket is in the `connect-in-progress` or `connected` state.
@since(version = 0.2.0)
set-listen-backlog-size: func(value: u64) -> result<_, error-code>;
/// Enables or disables keepalive.
///
/// The keepalive behavior can be adjusted using:
/// - `keep-alive-idle-time`
/// - `keep-alive-interval`
/// - `keep-alive-count`
/// These properties can be configured while `keep-alive-enabled` is false, but only come into effect when `keep-alive-enabled` is true.
///
/// Equivalent to the SO_KEEPALIVE socket option.
@since(version = 0.2.0)
keep-alive-enabled: func() -> result<bool, error-code>;
@since(version = 0.2.0)
set-keep-alive-enabled: func(value: bool) -> result<_, error-code>;
/// Amount of time the connection has to be idle before TCP starts sending keepalive packets.
///
/// If the provided value is 0, an `invalid-argument` error is returned.
/// Any other value will never cause an error, but it might be silently clamped and/or rounded.
/// I.e. after setting a value, reading the same setting back may return a different value.
///
/// Equivalent to the TCP_KEEPIDLE socket option. (TCP_KEEPALIVE on MacOS)
///
/// # Typical errors
/// - `invalid-argument`: (set) The provided value was 0.
@since(version = 0.2.0)
keep-alive-idle-time: func() -> result<duration, error-code>;
@since(version = 0.2.0)
set-keep-alive-idle-time: func(value: duration) -> result<_, error-code>;
/// The time between keepalive packets.
///
/// If the provided value is 0, an `invalid-argument` error is returned.
/// Any other value will never cause an error, but it might be silently clamped and/or rounded.
/// I.e. after setting a value, reading the same setting back may return a different value.
///
/// Equivalent to the TCP_KEEPINTVL socket option.
///
/// # Typical errors
/// - `invalid-argument`: (set) The provided value was 0.
@since(version = 0.2.0)
keep-alive-interval: func() -> result<duration, error-code>;
@since(version = 0.2.0)
set-keep-alive-interval: func(value: duration) -> result<_, error-code>;
/// The maximum amount of keepalive packets TCP should send before aborting the connection.
///
/// If the provided value is 0, an `invalid-argument` error is returned.
/// Any other value will never cause an error, but it might be silently clamped and/or rounded.
/// I.e. after setting a value, reading the same setting back may return a different value.
///
/// Equivalent to the TCP_KEEPCNT socket option.
///
/// # Typical errors
/// - `invalid-argument`: (set) The provided value was 0.
@since(version = 0.2.0)
keep-alive-count: func() -> result<u32, error-code>;
@since(version = 0.2.0)
set-keep-alive-count: func(value: u32) -> result<_, error-code>;
/// Equivalent to the IP_TTL & IPV6_UNICAST_HOPS socket options.
///
/// If the provided value is 0, an `invalid-argument` error is returned.
///
/// # Typical errors
/// - `invalid-argument`: (set) The TTL value must be 1 or higher.
@since(version = 0.2.0)
hop-limit: func() -> result<u8, error-code>;
@since(version = 0.2.0)
set-hop-limit: func(value: u8) -> result<_, error-code>;
/// The kernel buffer space reserved for sends/receives on this socket.
///
/// If the provided value is 0, an `invalid-argument` error is returned.
/// Any other value will never cause an error, but it might be silently clamped and/or rounded.
/// I.e. after setting a value, reading the same setting back may return a different value.
///
/// Equivalent to the SO_RCVBUF and SO_SNDBUF socket options.
///
/// # Typical errors
/// - `invalid-argument`: (set) The provided value was 0.
@since(version = 0.2.0)
receive-buffer-size: func() -> result<u64, error-code>;
@since(version = 0.2.0)
set-receive-buffer-size: func(value: u64) -> result<_, error-code>;
@since(version = 0.2.0)
send-buffer-size: func() -> result<u64, error-code>;
@since(version = 0.2.0)
set-send-buffer-size: func(value: u64) -> result<_, error-code>;
/// Create a `pollable` which can be used to poll for, or block on,
/// completion of any of the asynchronous operations of this socket.
///
/// When `finish-bind`, `finish-listen`, `finish-connect` or `accept`
/// return `error(would-block)`, this pollable can be used to wait for
/// their success or failure, after which the method can be retried.
///
/// The pollable is not limited to the async operation that happens to be
/// in progress at the time of calling `subscribe` (if any). Theoretically,
/// `subscribe` only has to be called once per socket and can then be
/// (re)used for the remainder of the socket's lifetime.
///
/// See <https://github.com/WebAssembly/wasi-sockets/blob/main/TcpSocketOperationalSemantics.md#pollable-readiness>
/// for more information.
///
/// Note: this function is here for WASI 0.2 only.
/// It's planned to be removed when `future` is natively supported in Preview3.
@since(version = 0.2.0)
subscribe: func() -> pollable;
/// Initiate a graceful shutdown.
///
/// - `receive`: The socket is not expecting to receive any data from
/// the peer. The `input-stream` associated with this socket will be
/// closed. Any data still in the receive queue at time of calling
/// this method will be discarded.
/// - `send`: The socket has no more data to send to the peer. The `output-stream`
/// associated with this socket will be closed and a FIN packet will be sent.
/// - `both`: Same effect as `receive` & `send` combined.
///
/// This function is idempotent; shutting down a direction more than once
/// has no effect and returns `ok`.
///
/// The shutdown function does not close (drop) the socket.
///
/// # Typical errors
/// - `invalid-state`: The socket is not in the `connected` state. (ENOTCONN)
///
/// # References
/// - <https://pubs.opengroup.org/onlinepubs/9699919799/functions/shutdown.html>
/// - <https://man7.org/linux/man-pages/man2/shutdown.2.html>
/// - <https://learn.microsoft.com/en-us/windows/win32/api/winsock/nf-winsock-shutdown>
/// - <https://man.freebsd.org/cgi/man.cgi?query=shutdown&sektion=2>
@since(version = 0.2.0)
shutdown: func(shutdown-type: shutdown-type) -> result<_, error-code>;
}
}