1 2.. _tcp: 3 4:c:type:`uv_tcp_t` --- TCP handle 5================================= 6 7TCP handles are used to represent both TCP streams and servers. 8 9:c:type:`uv_tcp_t` is a 'subclass' of :c:type:`uv_stream_t`. 10 11 12Data types 13---------- 14 15.. c:type:: uv_tcp_t 16 17 TCP handle type. 18 19 20Public members 21^^^^^^^^^^^^^^ 22 23N/A 24 25.. seealso:: The :c:type:`uv_stream_t` members also apply. 26 27 28API 29--- 30 31.. c:function:: int uv_tcp_init(uv_loop_t* loop, uv_tcp_t* handle) 32 33 Initialize the handle. No socket is created as of yet. 34 35.. c:function:: int uv_tcp_init_ex(uv_loop_t* loop, uv_tcp_t* handle, unsigned int flags) 36 37 Initialize the handle with the specified flags. At the moment only the lower 8 bits 38 of the `flags` parameter are used as the socket domain. A socket will be created 39 for the given domain. If the specified domain is ``AF_UNSPEC`` no socket is created, 40 just like :c:func:`uv_tcp_init`. 41 42 .. versionadded:: 1.7.0 43 44.. c:function:: int uv_tcp_open(uv_tcp_t* handle, uv_os_sock_t sock) 45 46 Open an existing file descriptor or SOCKET as a TCP handle. 47 48 .. versionchanged:: 1.2.1 the file descriptor is set to non-blocking mode. 49 50 .. note:: 51 The passed file descriptor or SOCKET is not checked for its type, but 52 it's required that it represents a valid stream socket. 53 54.. c:function:: int uv_tcp_nodelay(uv_tcp_t* handle, int enable) 55 56 Enable `TCP_NODELAY`, which disables Nagle's algorithm. 57 58.. c:function:: int uv_tcp_keepalive(uv_tcp_t* handle, int enable, unsigned int delay) 59 60 Enable / disable TCP keep-alive. `delay` is the initial delay in seconds, 61 ignored when `enable` is zero. 62 63 After `delay` has been reached, 10 successive probes, each spaced 1 second 64 from the previous one, will still happen. If the connection is still lost 65 at the end of this procedure, then the handle is destroyed with a 66 ``UV_ETIMEDOUT`` error passed to the corresponding callback. 67 68.. c:function:: int uv_tcp_simultaneous_accepts(uv_tcp_t* handle, int enable) 69 70 Enable / disable simultaneous asynchronous accept requests that are 71 queued by the operating system when listening for new TCP connections. 72 73 This setting is used to tune a TCP server for the desired performance. 74 Having simultaneous accepts can significantly improve the rate of accepting 75 connections (which is why it is enabled by default) but may lead to uneven 76 load distribution in multi-process setups. 77 78.. c:function:: int uv_tcp_bind(uv_tcp_t* handle, const struct sockaddr* addr, unsigned int flags) 79 80 Bind the handle to an address and port. `addr` should point to an 81 initialized ``struct sockaddr_in`` or ``struct sockaddr_in6``. 82 83 When the port is already taken, you can expect to see an ``UV_EADDRINUSE`` 84 error from either :c:func:`uv_tcp_bind`, :c:func:`uv_listen` or 85 :c:func:`uv_tcp_connect`. That is, a successful call to this function does 86 not guarantee that the call to :c:func:`uv_listen` or :c:func:`uv_tcp_connect` 87 will succeed as well. 88 89 `flags` can contain ``UV_TCP_IPV6ONLY``, in which case dual-stack support 90 is disabled and only IPv6 is used. 91 92.. c:function:: int uv_tcp_getsockname(const uv_tcp_t* handle, struct sockaddr* name, int* namelen) 93 94 Get the current address to which the handle is bound. `name` must point to 95 a valid and big enough chunk of memory, ``struct sockaddr_storage`` is 96 recommended for IPv4 and IPv6 support. 97 98.. c:function:: int uv_tcp_getpeername(const uv_tcp_t* handle, struct sockaddr* name, int* namelen) 99 100 Get the address of the peer connected to the handle. `name` must point to 101 a valid and big enough chunk of memory, ``struct sockaddr_storage`` is 102 recommended for IPv4 and IPv6 support. 103 104.. c:function:: int uv_tcp_connect(uv_connect_t* req, uv_tcp_t* handle, const struct sockaddr* addr, uv_connect_cb cb) 105 106 Establish an IPv4 or IPv6 TCP connection. Provide an initialized TCP handle 107 and an uninitialized :c:type:`uv_connect_t`. `addr` should point to an 108 initialized ``struct sockaddr_in`` or ``struct sockaddr_in6``. 109 110 On Windows if the `addr` is initialized to point to an unspecified address 111 (``0.0.0.0`` or ``::``) it will be changed to point to ``localhost``. 112 This is done to match the behavior of Linux systems. 113 114 The callback is made when the connection has been established or when a 115 connection error happened. 116 117 .. versionchanged:: 1.19.0 added ``0.0.0.0`` and ``::`` to ``localhost`` 118 mapping 119 120.. seealso:: The :c:type:`uv_stream_t` API functions also apply. 121 122.. c:function:: int uv_tcp_close_reset(uv_tcp_t* handle, uv_close_cb close_cb) 123 124 Resets a TCP connection by sending a RST packet. This is accomplished by 125 setting the `SO_LINGER` socket option with a linger interval of zero and 126 then calling :c:func:`uv_close`. 127 Due to some platform inconsistencies, mixing of :c:func:`uv_shutdown` and 128 :c:func:`uv_tcp_close_reset` calls is not allowed. 129 130 .. versionadded:: 1.32.0 131