LuaSocket: UDP support

From ff0f488c97fe8b554b909a0057cebc4c860eac8f Mon Sep 17 00:00:00 2001 From: chai Date: Wed, 20 Oct 2021 13:40:34 +0800 Subject: +luasocket src --- ThirdParty/luasocket/doc/udp.html | 596 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 596 insertions(+) create mode 100644 ThirdParty/luasocket/doc/udp.html (limited to 'ThirdParty/luasocket/doc/udp.html') diff --git a/ThirdParty/luasocket/doc/udp.html b/ThirdParty/luasocket/doc/udp.html new file mode 100644 index 0000000..4618aad --- /dev/null +++ b/ThirdParty/luasocket/doc/udp.html @@ -0,0 +1,596 @@ + + + + + + +LuaSocket: UDP support + + + + + + + + + + + + +

UDP

+ + + +

+connected:close()
+unconnected:close() +

+ +

+Closes a UDP object. The internal socket +used by the object is closed and the local address to which the +object was bound is made available to other applications. No +further operations (except for further calls to the close +method) are allowed on a closed socket. +

+ +

+Note: It is important to close all used sockets +once they are not needed, since, in many systems, each socket uses +a file descriptor, which are limited system resources. +Garbage-collected objects are automatically closed before +destruction, though. +

+ + + +

+connected:getoption()
+unconnected:getoption() +

+ +

+Gets an option value from the UDP object. +See setoption for +description of the option names and values. +

+ +

Option is a string with the option name. +

'dontroute' +
'broadcast' +
'reuseaddr' +
'reuseport' +
'ip-multicast-loop' +
'ipv6-v6only' +
'ip-multicast-if' +
'ip-multicast-ttl' +
'ip-add-membership' +
'ip-drop-membership' +

+ +

+The method returns the option value in case of +success, or +nil followed by an error message otherwise. +

+ + + +

+connected:getpeername() +

+ +

+Retrieves information about the peer +associated with a connected UDP object. +

+ + +

+Returns a string with the IP address of the peer, the +port number that peer is using for the connection, +and a string with the family ("inet" or "inet6"). +In case of error, the method returns nil. +

+ +

+Note: It makes no sense to call this method on unconnected objects. +

+ + + +

+connected:getsockname()
+unconnected:getsockname() +

+ +

+Returns the local address information associated to the object. +

+ + +

+The method returns a string with local IP address, a number with +the local port, +and a string with the family ("inet" or "inet6"). +In case of error, the method returns nil. +

+ +

+Note: UDP sockets are not bound to any address +until the setsockname or the +sendto method is called for the +first time (in which case it is bound to an ephemeral port and the +wild-card address). +

+ + + +

+connected:settimeout(value)
+unconnected:settimeout(value) +

+ +

+Returns the current timeout value. +

+ + + + +

+connected:receive([size])
+unconnected:receive([size]) +

+ +

+Receives a datagram from the UDP object. If +the UDP object is connected, only datagrams coming from the peer +are accepted. Otherwise, the returned datagram can come from any +host. +

+ +

+The optional size parameter +specifies the maximum size of the datagram to be retrieved. If +there are more than size bytes available in the datagram, +the excess bytes are discarded. If there are less then +size bytes available in the current datagram, the +available bytes are returned. +If size is omitted, the +compile-time constant socket._DATAGRAMSIZE is used +(it defaults to 8192 bytes). Larger sizes will cause a +temporary buffer to be allocated for the operation. +

+ +

+In case of success, the method returns the +received datagram. In case of timeout, the method returns +nil followed by the string 'timeout'. +

+ + + +

+unconnected:receivefrom([size]) +

+ +

+Works exactly as the receive +method, except it returns the IP +address and port as extra return values (and is therefore slightly less +efficient). +

+ + + +

+connected:send(datagram) +

+ +

+Sends a datagram to the UDP peer of a connected object. +

+ +

+Datagram is a string with the datagram contents. +The maximum datagram size for UDP is 64K minus IP layer overhead. +However datagrams larger than the link layer packet size will be +fragmented, which may deteriorate performance and/or reliability. +

+ +

+If successful, the method returns 1. In case of +error, the method returns nil followed by an error message. +

+ +

+Note: In UDP, the send method never blocks +and the only way it can fail is if the underlying transport layer +refuses to send a message to the specified address (i.e. no +interface accepts the address). +

+ + + +

+unconnected:sendto(datagram, ip, port) +

+ +

+Sends a datagram to the specified IP address and port number. +

+ +

+Datagram is a string with the +datagram contents. +The maximum datagram size for UDP is 64K minus IP layer overhead. +However datagrams larger than the link layer packet size will be +fragmented, which may deteriorate performance and/or reliability. +Ip is the IP address of the recipient. +Host names are not allowed for performance reasons. + +Port is the port number at the recipient. +

+ +

+If successful, the method returns 1. In case of +error, the method returns nil followed by an error message. +

+ +

+ + + +

+connected:setoption(option [, value])
+unconnected:setoption(option [, value]) +

+ +

+Sets options for the UDP object. Options are +only needed by low-level or time-critical applications. You should +only modify an option if you are sure you need it.

Option is a string with the option +name, and value depends on the option being set: +

+ +

'dontroute': Indicates that outgoing +messages should bypass the standard routing facilities. +Receives a boolean value; +
'broadcast': Requests permission to send +broadcast datagrams on the socket. +Receives a boolean value; +
'reuseaddr': Indicates that the rules used in +validating addresses supplied in a bind() call +should allow reuse of local addresses. +Receives a boolean value; +
'reuseport': Allows completely duplicate +bindings by multiple processes if they all set +'reuseport' before binding the port. +Receives a boolean value; +
'ip-multicast-loop': +Specifies whether or not a copy of an outgoing multicast +datagram is delivered to the sending host as long as it is a +member of the multicast group. +Receives a boolean value; +
'ipv6-v6only': +Specifies whether to restrict inet6 sockets to +sending and receiving only IPv6 packets. +Receive a boolean value; +
'ip-multicast-if': +Sets the interface over which outgoing multicast datagrams +are sent. +Receives an IP address; +
'ip-multicast-ttl': +Sets the Time To Live in the IP header for outgoing +multicast datagrams. +Receives a number; +
'ip-add-membership': +Joins the multicast group specified. +Receives a table with fields +multiaddr and interface, each containing an +IP address; +
'ip-drop-membership': Leaves the multicast +group specified. +Receives a table with fields +multiaddr and interface, each containing an +IP address. +

+ +

+The method returns 1 in case of success, or +nil followed by an error message otherwise. +

+ +

+Note: The descriptions above come from the man pages. +

+ + + + +

+connected:setpeername('*')
+unconnected:setpeername(address, port) +

+ +

+Changes the peer of a UDP object. This +method turns an unconnected UDP object into a connected UDP +object or vice versa. +

+ +

+For connected objects, outgoing datagrams +will be sent to the specified peer, and datagrams received from +other peers will be discarded by the OS. Connected UDP objects must +use the send and +receive methods instead of +sendto and +receivefrom. +

+ +

+Address can be an IP address or a +host name. Port is the port number. If address is +'*' and the object is connected, the peer association is +removed and the object becomes an unconnected object again. In that +case, the port argument is ignored. +

+ +

+In case of error the method returns +nil followed by an error message. In case of success, the +method returns 1. +

+ +

+Note: Since the address of the peer does not have +to be passed to and from the OS, the use of connected UDP objects +is recommended when the same peer is used for several transmissions +and can result in up to 30% performance gains. +

+ +

+Note: Starting with LuaSocket 3.0, the host name resolution +depends on whether the socket was created by socket.udp or socket.udp6. Addresses from +the appropriate family are tried in succession until the +first success or until the last failure. +

+ + + +

+unconnected:setsockname(address, port) +

+ +

+Binds the UDP object to a local address. +

+ +

+Address can be an IP address or a +host name. If address is '*' the system binds to +all local interfaces using the constant INADDR_ANY. If +port is 0, the system chooses an ephemeral port. +

+ +

+If successful, the method returns 1. In case of +error, the method returns nil followed by an error +message. +

+ +

+Note: This method can only be called before any +datagram is sent through the UDP object, and only once. Otherwise, +the system automatically binds the object to all local interfaces +and chooses an ephemeral port as soon as the first datagram is +sent. After the local address is set, either automatically by the +system or explicitly by setsockname, it cannot be +changed. +

+ + + +

+connected:settimeout(value)
+unconnected:settimeout(value) +

+ +

+Changes the timeout values for the object. By default, the +receive and +receivefrom +operations are blocking. That is, any call to the methods will block +indefinitely, until data arrives. The settimeout function defines +a limit on the amount of time the functions can block. When a timeout is +set and the specified amount of time has elapsed, the affected methods +give up and fail with an error code. +

+ +

+The amount of time to wait is specified as +the value parameter, in seconds. The nil timeout +value allows operations to block indefinitely. Negative +timeout values have the same effect. +

+ +

+Note: In UDP, the send +and sendto methods never block (the +datagram is just passed to the OS and the call returns +immediately). Therefore, the settimeout method has no +effect on them. +

+ +

+Note: The old timeout method is +deprecated. The name has been changed for sake of uniformity, since +all other method names already contained verbs making their +imperative nature obvious. +

+ + + +

+socket.udp() +

+ +

+Creates and returns an unconnected UDP object. +Unconnected objects support the +sendto, +receive, +receivefrom, +getoption, +getsockname, +setoption, +settimeout, +setpeername, +setsockname, and +close. +The setpeername +is used to connect the object. +

+ +

+In case of success, a new unconnected UDP object +returned. In case of error, nil is returned, followed by +an error message. +

+ +

+Note: The choice between IPv4 and IPv6 happens during a call to +sendto, setpeername, or sockname, depending on the address +family obtained from the resolver. +

+ +

+Note: Before the choice between IPv4 and IPv6 happens, +the internal socket object is invalid and therefore setoption will fail. +

+ + + +

+socket.udp4() +

+ +

+Creates and returns an unconnected IPv4 UDP object. +Unconnected objects support the +sendto, +receive, +receivefrom, +getoption, +getsockname, +setoption, +settimeout, +setpeername, +setsockname, and +close. +The setpeername +is used to connect the object. +

+ +

+In case of success, a new unconnected UDP object +returned. In case of error, nil is returned, followed by +an error message. +

+ + + +

+socket.udp6() +

+ +

+Creates and returns an unconnected IPv6 UDP object. +Unconnected objects support the +sendto, +receive, +receivefrom, +getoption, +getsockname, +setoption, +settimeout, +setpeername, +setsockname, and +close. +The setpeername +is used to connect the object. +

+ +

+In case of success, a new unconnected UDP object +returned. In case of error, nil is returned, followed by +an error message. +

+ +

+Note: The TCP object returned will have the option +"ipv6-v6only" set to true. +

+ + + + + + + + + -- cgit v1.1-26-g67d0