sock_bind()

Binds a socket to a specific address.

Description

The sock_bind() function is used to bind a socket to a specific address. This function is similar to the bind function in POSIX, which is used to associate a specific address with a socket.

In POSIX, the bind function is typically used with sockets that use the PF_INET address family, which corresponds to IPv4 addresses. Similarly, in the WASI context, sock_bind() uses the PF_INET address family to bind the socket.

Binding a socket to a specific address allows the socket to receive incoming connections or send data from the specified address. It restricts the socket to operate on a specific network interface and port.

Syntax

  ;;; Note: This is similar to `bind` in POSIX using PF_INET
  ;;; Bind a socket
  (@interface func (export "sock_bind")
    ;;; File descriptor of the socket to be bind
    (param $fd $fd)
    ;;; Address to bind the socket to
    (param $addr (@witx const_pointer $addr_port))
    (result $error (expected (error $errno)))
  )

Parameters

• ctx: A mutable reference to the function environment.
• sock: The file descriptor of the socket to bind.
• addr: A WebAssembly pointer to the address to bind the socket to.

Return Value

The function returns an Errno value indicating the outcome of the operation. If the operation is successful, Errno::Success is returned. If an error occurs, an appropriate Errno value is returned.

Notes

• The sock_bind() function is used to associate a specific address with a socket.
• The behavior and limitations of the sock_bind() function may vary depending on the specific runtime environment and underlying networking implementation. It is important to consult the documentation or specifications of the specific environment to understand its behavior in that context.
• In POSIX, the bind function can be used with different address families and protocols, such as IPv6 (PF_INET6) and Unix domain sockets (PF_UNIX). However, in the current context of WASI, the sock_bind() function specifically uses the PF_INET address family to bind the socket.
• The addr parameter should contain the IP address and port number to which the socket will be bound.

Sock Address In Layout

For information on valid sin_family values refer to the documentation on sock_open()

IPv4

interface sockaddr_in {
  sin_family: i16;
  sin_port:   i16;
  sin_addr:   i8[4]; // IPv4 address, i.e. 124.456.789.012
  sin_zero:   i8[8]; // padding for size compatibility with sockaddr
}

IPv6

interface sockaddr_in6 {
  sin6_family:   i16;
  sin6_port:     i16;
  sin6_flowinfo: i32;
  sin6_addr:     i16[8];
  sin6_scope_id: i32;
}

IPC

interface sockaddr_un {
  sun_family: i16;
  sun_path:   i8[108];
}