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 :c:func:`uv_listen` or :c:func:`uv_tcp_connect`. That is, 85 a successful call to this function does not guarantee that the call 86 to :c:func:`uv_listen` or :c:func:`uv_tcp_connect` will succeed as well. 87 88 `flags` can contain ``UV_TCP_IPV6ONLY``, in which case dual-stack support 89 is disabled and only IPv6 is used. 90 91.. c:function:: int uv_tcp_getsockname(const uv_tcp_t* handle, struct sockaddr* name, int* namelen) 92 93 Get the current address to which the handle is bound. `name` must point to 94 a valid and big enough chunk of memory, ``struct sockaddr_storage`` is 95 recommended for IPv4 and IPv6 support. 96 97.. c:function:: int uv_tcp_getpeername(const uv_tcp_t* handle, struct sockaddr* name, int* namelen) 98 99 Get the address of the peer connected to the handle. `name` must point to 100 a valid and big enough chunk of memory, ``struct sockaddr_storage`` is 101 recommended for IPv4 and IPv6 support. 102 103.. c:function:: int uv_tcp_connect(uv_connect_t* req, uv_tcp_t* handle, const struct sockaddr* addr, uv_connect_cb cb) 104 105 Establish an IPv4 or IPv6 TCP connection. Provide an initialized TCP handle 106 and an uninitialized :c:type:`uv_connect_t`. `addr` should point to an 107 initialized ``struct sockaddr_in`` or ``struct sockaddr_in6``. 108 109 On Windows if the `addr` is initialized to point to an unspecified address 110 (``0.0.0.0`` or ``::``) it will be changed to point to ``localhost``. 111 This is done to match the behavior of Linux systems. 112 113 The callback is made when the connection has been established or when a 114 connection error happened. 115 116 .. versionchanged:: 1.19.0 added ``0.0.0.0`` and ``::`` to ``localhost`` 117 mapping 118 119.. seealso:: The :c:type:`uv_stream_t` API functions also apply. 120 121.. c:function:: int uv_tcp_close_reset(uv_tcp_t* handle, uv_close_cb close_cb) 122 123 Resets a TCP connection by sending a RST packet. This is accomplished by 124 setting the `SO_LINGER` socket option with a linger interval of zero and 125 then calling :c:func:`uv_close`. 126 Due to some platform inconsistencies, mixing of :c:func:`uv_shutdown` and 127 :c:func:`uv_tcp_close_reset` calls is not allowed. 128 129 .. versionadded:: 1.32.0 130 131.. c:function:: int uv_socketpair(int type, int protocol, uv_os_sock_t socket_vector[2], int flags0, int flags1) 132 133 Create a pair of connected sockets with the specified properties. 134 The resulting handles can be passed to `uv_tcp_open`, used with `uv_spawn`, 135 or for any other purpose. 136 137 Valid values for `flags0` and `flags1` are: 138 139 - UV_NONBLOCK_PIPE: Opens the specified socket handle for `OVERLAPPED` 140 or `FIONBIO`/`O_NONBLOCK` I/O usage. 141 This is recommended for handles that will be used by libuv, 142 and not usually recommended otherwise. 143 144 Equivalent to :man:`socketpair(2)` with a domain of AF_UNIX. 145 146 .. versionadded:: 1.41.0 147