From e5875001247e6a6ac4f474157a51a8c54f94ae49 Mon Sep 17 00:00:00 2001
From: Hans Bolinder Received Set a network namespace for the socket. The This option uses the Linux specific syscall
+
+ The virtual machine also needs elevated privileges either
+ running as superuser or (for Linux) having the capability
+ The Received A function that may be useful is A function that may be useful is Parses an ip_address() and returns an IPv4 or IPv6 address string. Sets one or more options for a socket. The following options
are available: If the value is
+setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp
+
+ Note also that the filesystem containing the virtual machine
+ executable (
-1> inet_parse:address("192.168.42.2").
+1> inet:parse_address("192.168.42.2").
{ok,{192,168,42,2}}
-2> inet_parse:address("FFFF::192.168.42.2").
+2> inet:parse_address("FFFF::192.168.42.2").
{ok,{65535,0,0,0,0,0,49320,10754}}
--
cgit v1.2.3
From e547c997a4e516d3474e577bd4747e249303a7c7 Mon Sep 17 00:00:00 2001
From: Fredrik Gustafsson
If the value is
When using
If the value is an integer
When using
Note that
Note that
+ The same as
+
+ Returns a list of all address/port number pairs for the other end
+ of a socket's association
+ This function can return multiple addresses for multihomed
+ sockets such as SCTP sockets. For other sockets it does the
+ same as
+ Note that the
Returns the local address and port number for a socket.
+ The same as
+
+ Returns a list of all local address/port number pairs for a socket
+ for the given association
+ This function can return multiple addresses for multihomed
+ sockets such as SCTP sockets. For other sockets it does the
+ same as
+ Note that the
Returns the address and port for the other end of a - connection.
++ Returns the address and port for the other end of a + connection. +
+
+ Note that for SCTP sockets this function only returns
+ one of the socket's peer addresses. The function
+
- The same as
-
This function can return multiple addresses for multihomed
- sockets such as SCTP sockets. For other sockets it does the
- same as
- Note that the Returns the local address and port number for a socket.
+ Note that for SCTP sockets this function only returns
+ one of the socket addresses. The function
+
- The same as
-
This function can return multiple addresses for multihomed
- sockets such as SCTP sockets. For other sockets it does the
- same as
- Note that the
Average packet size deviation in bytes received sent from the socket.
+Average packet size deviation in bytes sent from the socket.
Returns the state of the Inet configuration database in +
Returns the state of the Inet configuration database in form of a list of recorded configuration parameters. (See the ERTS User's Guide, Inet configuration, for more information). Only parameters with other than default values are returned.
@@ -258,8 +258,8 @@ fe80::204:acff:fe17:bf38Gets one or more options for a socket.
- See
Gets one or more options for a socket.
+ See
The number of elements in the returned
Asking for and inspecting raw socket options require low level information about the current operating system and TCP @@ -306,7 +306,7 @@ fe80::204:acff:fe17:bf38 value to be a 32 bit integer. We could use the following code to retrieve the value:
+ get_tcpi_sacked(Sock) ->
{ok,[{raw,_,_,Info}]} = inet:getopts(Sock,[{raw,6,11,92}]),
<<_:28/binary,TcpiSacked:32/native,_/binary>> = Info,
TcpiSacked.]]>
@@ -408,7 +408,7 @@ fe80::204:acff:fe17:bf38
Parses an IPv6 address string and returns an ip6_address(). +
Parses an IPv6 address string and returns an ip6_address(). Does not accept IPv4 adresses.
Determines the size of the user-level software buffer used by
- the driver. Not to be confused with
The size of the user-level software buffer used by
+ the driver. Not to be confused with
Gives the size of the receive buffer to use for - the socket.
+The minimum size of the receive buffer to use for
+ the socket. You are encouraged to use
+
Gives the size of the send buffer to use for the socket.
+The minimum size of the send buffer to use for the socket.
+ You are encouraged to use
+
Sets the SO_PRIORITY socket level option on platforms where - this is implemented. The behaviour and allowed range varies on - different systems. The option is ignored on platforms where the +
Sets the SO_PRIORITY socket level option on platforms where + this is implemented. The behaviour and allowed range varies on + different systems. The option is ignored on platforms where the option is not implemented. Use with caution.
Sets IP_TOS IP level options on platforms where this is - implemented. The behaviour and allowed range varies on different - systems. The option is ignored on platforms where the option is +
Sets IP_TOS IP level options on platforms where this is + implemented. The behaviour and allowed range varies on different + systems. The option is ignored on platforms where the option is not implemented. Use with caution.
Average size of packets in bytes received to the socket.
+Average size of packets in bytes received by the socket.
Number of packets received to the socket.
+Number of packets received by the socket.
Average packet size deviation in bytes received to the socket.
+Average packet size deviation in bytes received by the socket.
The size of the largest packet in bytes received to the socket.
+The size of the largest packet in bytes received by the socket.
Number of bytes received to the socket.
+Number of bytes received by the socket.
When this option is set to
Setting this option to
A connected socket returned from
+
The minimum size of the send buffer to use for the socket.
--
cgit v1.2.3
From 0098eed847516cc6760d961421c83527816e35ae Mon Sep 17 00:00:00 2001
From: Rory Byrne
A connected socket returned from
Sets the line delimiting character for line oriented protocols
+ (
Set the protocol-defined priority for all packets to be sent
--
cgit v1.2.3
From 02aca536aec93edd799d67615e47bdb7b5babf4a Mon Sep 17 00:00:00 2001
From: Hans Bolinder See
Do not rely too much on the order of
The Parses an ip_address() and returns an IPv4 or IPv6 address string. Parses an Parses an IPv4 address string and returns an ip4_address().
+ Parses an IPv4 address string and returns an Parses an IPv4 address string containing four fields, i.e not shortened, and returns an ip4_address(). Parses an IPv4 address string containing four fields, i.e not shortened, and returns an Parses an IPv6 address string and returns an ip6_address().
+ Parses an IPv6 address string and returns an Parses an IPv6 address string and returns an ip6_address().
- Does not accept IPv4 adresses. Parses an IPv6 address string and returns an Parses an IPv4 or IPv6 address string and returns an ip4_address() or ip6_address(). Accepts a shortened IPv4 address string. Parses an IPv4 or IPv6 address string and returns an Parses an IPv4 or IPv6 address string and returns an ip4_address() or ip6_address(). Does not accept a shortened IPv4 address string. Parses an IPv4 or IPv6 address string and returns an
+ Example:
setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp
- Note also that the filesystem containing the virtual machine
+ Note also that the filesystem containing the virtual machine
executable ( Provides access to TCP/IP protocols. See also ERTS User's Guide, Inet configuration for more
- information on how to configure an Erlang runtime system for IP
- communication. Two Kernel configuration parameters affect the behaviour of all
- sockets opened on an Erlang node:
- This module provides access to TCP/IP protocols. See also
+ The following two When Using the Kernel configuration parameters mentioned above, one
- can set default options for all TCP sockets on a node. This should
- be used with care, but options like Using the Note that the default option Notice that default option Addresses as inputs to functions can be either a string or a
- tuple. For instance, the IP address 150.236.20.73 can be passed to
- IPv4 address examples:
+
+
$ erl -sname test -kernel \
inet_default_connect_options '[{delay_send,true}]' \
inet_default_listen_options '[{delay_send,true}]'
-
IPv4 address examples:
Address ip_address()
------- ------------
127.0.0.1 {127,0,0,1}
192.168.42.2 {192,168,42,2}
- IPv6 address examples:
+IPv6 address examples:
Address ip_address()
------- ------------
@@ -77,7 +81,9 @@ FFFF::192.168.42.2
{16#3ffe,16#b80,16#1f8d,16#2,16#204,16#acff,16#fe17,16#bf38}
fe80::204:acff:fe17:bf38
{16#fe80,0,0,0,0,16#204,16#acff,16#fe17,16#bf38}
- A function that may be useful is
Function
+
1> inet:parse_address("192.168.42.2"). {ok,{192,168,42,2}} @@ -89,9 +95,12 @@ fe80::204:acff:fe17:bf38- +The record is defined in the Kernel include file "inet.hrl". - Add the following directive to the module:
--include_lib("kernel/include/inet.hrl").
The record is defined in the
+Kernel include file +"inet.hrl" .Add the following directive to the module:
++-include_lib("kernel/include/inet.hrl").
+@@ -110,17 +119,20 @@ fe80::204:acff:fe17:bf38 - An atom which is named from the Posix error codes - used in Unix, and in the runtime libraries of most - C compilers. See +
+ An atom that is named from the POSIX error codes used in Unix, + and in the runtime libraries of most C compilers. See section
POSIX Error Codes .socket() -+
- See gen_tcp(3) - andgen_udp(3) .+
See + + and + gen_tcp:type-socket . + gen_udp:type-socket @@ -131,443 +143,415 @@ fe80::204:acff:fe17:bf38 + - Close a socket of any type +Close a socket of any type. Closes a socket of any type.
- +- Return a list of IP configuration parameters ++ Return a descriptive string for an error reason. - Returns the state of the Inet configuration database in - form of a list of recorded configuration parameters. (See the - ERTS User's Guide, Inet configuration, for more information). - Only parameters with other than default values are returned.
+Returns a diagnostic error string. For possible POSIX values and + corresponding strings, see section +
POSIX Error Codes .- +- Return a descriptive string for an error reason ++ Return a list of IP configuration parameters. - Returns a diagnostic error string. See the section below - for possible Posix values and the corresponding - strings.
+Returns the state of the
Inet configuration database in + form of a list of recorded configuration parameters. For more + information, seeERTS User's Guide: + Inet Configuration . + Only parameters with other than default values are returned.+ - Return the IP-address for a host +Return the IP address for a host. - Returns the IP-address for
+as a tuple of - integers. Host can be an IP-address, a single hostname - or a fully qualified hostname. Host Returns the IP address for
as a tuple of + integers. Host can be an IP address, a single + hostname, or a fully qualified hostname. Host + - Return the IP-addresses for a host +Return the IP addresses for a host. - Returns a list of all IP-addresses for
+. - Host can be an IP-address, a single hostname or a fully - qualified hostname. Host Returns a list of all IP addresses for
. + Host can be an IP address, a single hostname, or + a fully qualified hostname. Host + - Return a hostent record for the host with the given address +Return a hostent record for the host with the specified + address. - +Returns a
-hostent record given an address.Returns a
hostent record for the host with the specified + address.+ - Return a hostent record for the host with the given name +Return a hostent record for the host with the specified name. + - Returns a
+hostent record given a hostname.Returns a
hostent record for the host with the specified + hostname.+ - Return a hostent record for the host with the given name +Return a hostent record for the host with the specified name. + - Returns a
+hostent record given a hostname, restricted - to the given address family.Returns a
hostent record for the host with the specified + name, restricted to the specified address family.- Return the local hostname +Return the local hostname. - Returns the local hostname. Will never fail.
+Returns the local hostname. Never fails.
- Return a list of interfaces and their addresses -- +- Returns a list of 2-tuples containing interface names and the - interface's addresses.
-is a Unicode string. - Ifname is hardware dependent, e.g on Ethernet interfaces - it is the 6-byte Ethernet address (MAC address (EUI-48 address)). - Hwaddr - The
-{addr, ,Addr }{netmask,_} and{broadaddr,_} - tuples are repeated in the result list iff the interface has multiple - addresses. If you come across an interface that has - multiple{flag,_} or{hwaddr,_} tuples you have - a really strange interface or possibly a bug in this function. - The{flag,_} tuple is mandatory, all other optional. -- Do not rely too much on the order of
-atoms or - Flag tuples. There are some rules, though: Ifopt -
-- - Immediately after
-{addr,_} follows{netmask,_} -- - Immediately thereafter follows
-{broadaddr,_} if - thebroadcast flag is not set and the -pointtopoint flag is set. -- - Any
-{netmask,_} ,{broadaddr,_} or -{dstaddr,_} tuples that follow an{addr,_} - tuple concerns that address. -- The
-{hwaddr,_} tuple is not returned on Solaris since the - hardware address historically belongs to the link layer and only - the superuser can read such addresses. -- On Windows, the data is fetched from quite different OS API - functions, so the
-and Netmask - values may be calculated, just as some Broadaddr values. - You have been warned. Report flagrant bugs. - Flag Return a list of interfaces and their addresses. ++ Returns a list of 2-tuples containing interface names and the + interface addresses.
+is a Unicode string. + Ifname is hardware dependent, for example, on + Ethernet interfaces + it is the 6-byte Ethernet address (MAC address (EUI-48 address)). Hwaddr The tuples
+{addr, ,Addr }{netmask,_} , and +{broadaddr,_} are repeated in the result list if the interface + has multiple addresses. If you come across an interface with + multiple{flag,_} or{hwaddr,_} tuples, you have + a strange interface or possibly a bug in this function. The tuple +{flag,_} is mandatory, all others are optional.Do not rely too much on the order of
+atoms + or Flag tuples. There are however some rules: Ifopt +
+- +
Immediately after +
{addr,_} follows{netmask,_} .- +
Immediately thereafter follows
{broadaddr,_} if flag +broadcast is not set and flag +pointtopoint is set.- +
Any
{netmask,_} ,{broadaddr,_} , or +{dstaddr,_} tuples that follow an{addr,_} + tuple concerns that address.The tuple
+{hwaddr,_} is not returned on Solaris, as the + hardware address historically belongs to the link layer and only + the superuser can read such addresses.+ +On Windows, the data is fetched from different OS API functions, + so the
+and Netmask + values can be calculated, just as some Broadaddr + values. Report flagrant bugs. Flag - Get one or more options for a socket +Get one or more options for a socket. - Gets one or more options for a socket. - See
-setopts/2 - for a list of available options.The number of elements in the returned
+ OptionValues Gets one or more options for a socket. For a list of available + options, see +
+. setopts/2 The number of elements in the returned +
-list does not necessarily correspond to the number of options asked for. If the operating system fails to support an option, - it is simply left out in the returned list. An error tuple is only - returned when getting options for the socket is impossible - (i.e. the socket is closed or the buffer size in a raw request + it is left out in the returned list. An error tuple is returned + only when getting options for the socket is impossible (that is, + the socket is closed or the buffer size in a raw request is too large). This behavior is kept for backward compatibility reasons. OptionValues A raw option request
RawOptReq = {raw, Protocol, OptionNum, ValueSpec} can be used to get information about +A raw option request +
-RawOptReq = {raw, Protocol, OptionNum, ValueSpec} + can be used to get information about socket options not (explicitly) supported by the emulator. The - use of raw socket options makes the code non portable, but + use of raw socket options makes the code non-portable, but allows the Erlang programmer to take advantage of unusual features present on the current platform.The
RawOptReq consists of the tagraw followed - by the protocol level, the option number and either a binary +-
RawOptReq consists of tagraw followed + by the protocol level, the option number, and either a binary or the size, in bytes, of the - buffer in which the option value is to be stored. A binary - should be used when the underlyinggetsockopt requires - input - in the argument field, in which case the size of the binary - should correspond to the required buffer + buffer in which the option value is to be stored. A binary is to be + used when the underlyinggetsockopt requires input + in the argument field. In this case, the binary size + is to correspond to the required buffer size of the return value. The supplied values in aRawOptReq - correspond to the second, third and fourth/fifth parameters to the + correspond to the second, third, and fourth/fifth parameters to thegetsockopt call in the C socket API. The value stored - in the buffer is returned as a binaryValueBin + in the buffer is returned as a binaryValueBin , where all values are coded in the native endianess.Asking for and inspecting raw socket options require low - level information about the current operating system and TCP - stack.
-As an example, consider a Linux machine where the -
+TCP_INFO option could be used to collect TCP statistics - for a socket. Lets say we're interested in the -tcpi_sacked field of thestruct tcp_info - filled in when asking forTCP_INFO . To - be able to access this information, we need to know both the - numeric value of the protocol levelIPPROTO_TCP , the - numeric value of the optionTCP_INFO , the size of the -struct tcp_info and the size and offset of - the specific field. By inspecting the headers or writing a small C - program, we foundIPPROTO_TCP to be 6, -TCP_INFO to be 11, the structure size to be 92 (bytes), - the offset oftcpi_sacked to be 28 bytes and the actual - value to be a 32 bit integer. We could use the following - code to retrieve the value:Asking for and inspecting raw socket options require low-level + information about the current operating system and TCP stack.
+Example:
+Consider a Linux machine where option +
+TCP_INFO can be used to collect TCP statistics + for a socket. Assume you are interested in field +tcpi_sacked ofstruct tcp_info + filled in when asking forTCP_INFO . To be able to access + this information, you need to know the following:+
+- The numeric value of protocol level
+IPPROTO_TCP - The numeric value of option
+TCP_INFO - The size of
+struct tcp_info - The size and offset of the specific field
+By inspecting the headers or writing a small C program, it is found + that
IPPROTO_TCP is 6,TCP_INFO is 11, the structure + size is 92 (bytes), the offset oftcpi_sacked is 28 bytes, + and the value is a 32-bit integer. The following code can be used + to retrieve the value:- {ok,[{raw,_,_,Info}]} = inet:getopts(Sock,[{raw,6,11,92}]), - <<_:28/binary,TcpiSacked:32/native,_/binary>> = Info, - TcpiSacked.]]>
-Preferably, you would check the machine type, the OS - and the kernel version prior to executing anything similar to the - code above.
+get_tcpi_sacked(Sock) -> + {ok,[{raw,_,_,Info}]} = inet:getopts(Sock,[{raw,6,11,92}]), + <<_:28/binary,TcpiSacked:32/native,_/binary>> = Info, + TcpiSacked.]]> +Preferably, you would check the machine type, the operating system, + and the
Kernel version before executing anything similar to + this code.+ - Get one or more statistic options for a socket +Get one or more statistic options for a socket. Gets one or more statistic options for a socket.
- --
getstat( is equivalent to -Socket )getstat( .Socket , [recv_avg, recv_cnt, recv_dvi, - recv_max, recv_oct, send_avg, send_cnt, send_dvi, send_max, - send_oct])The following options are available:
++
getstat( is equivalent to +Socket )getstat( .Socket , [recv_avg, recv_cnt, recv_dvi, + recv_max, recv_oct, send_avg, send_cnt, send_dvi, send_max, + send_oct])The following options are available:
- - recv_avg - -
-Average size of packets in bytes received by the socket.
-- recv_cnt - +
+ recv_avg - +
+Average size of packets, in bytes, received by the socket.
++ recv_cnt - -
Number of packets received by the socket.
-- recv_dvi - -
-Average packet size deviation in bytes received by the socket.
-- recv_max - -
-The size of the largest packet in bytes received by the socket.
-- recv_oct - +
++ recv_dvi - +
+Average packet size deviation, in bytes, received by the socket.
++ recv_max - +
+Size of the largest packet, in bytes, received by the socket.
++ recv_oct - - -
Number of bytes received by the socket.
-- send_avg - -
-Average size of packets in bytes sent from the socket.
-- send_cnt - +
++ send_avg - +
+Average size of packets, in bytes, sent from the socket.
++ send_cnt - -
Number of packets sent from the socket.
-- send_dvi - -
-Average packet size deviation in bytes sent from the socket.
-- send_max - -
-The size of the largest packet in bytes sent from the socket.
-- send_oct - +
++ send_dvi - +
+Average packet size deviation, in bytes, sent from the socket.
++ send_max - +
+Size of the largest packet, in bytes, sent from the socket.
++ send_oct - +
Number of bytes sent from the socket.
-+ + - Convert IPv6 / IPV4 adress to ascii +Convert IPv6/IPV4 address to ASCII. ++ +Parses an +
++ and returns an IPv4 or IPv6 address string. ip_address() + ++ Parse an IPv4 or IPv6 address. - Parses an
+ip_address() and returns an IPv4 or IPv6 address string.Parses an IPv4 or IPv6 address string and returns an +
or + ip4_address() . + Accepts a shortened IPv4 address string. ip6_address() + - Parse an IPv4 address +Parse an IPv4 address. - Parses an IPv4 address string and returns an
+ip4_address() . - Accepts a shortened IPv4 shortened address string.Parses an IPv4 address string and returns an +
. + Accepts a shortened IPv4 address string. ip4_address() + Parse an IPv4 address strict. - Parses an IPv4 address string containing four fields, i.e not shortened, and returns an
+ip4_address() .Parses an IPv4 address string containing four fields, that is, + not shortened, and returns an +
. + ip4_address() + - Parse an IPv6 address +Parse an IPv6 address. - Parses an IPv6 address string and returns an
+ip6_address() . - If an IPv4 address string is passed, an IPv4-mapped IPv6 address is returned.Parses an IPv6 address string and returns an +
. + If an IPv4 address string is specified, an IPv4-mapped IPv6 address + is returned. ip6_address() - Parse an IPv6 address strict. - -Parses an IPv6 address string and returns an
-ip6_address() . - Does not accept IPv4 adresses.- +- Parse an IPv4 or IPv6 address. -- Parses an IPv4 or IPv6 address string and returns an
+ip4_address() orip6_address() . Accepts a shortened IPv4 address string.Parses an IPv6 address string and returns an +
. + Does not accept IPv4 addresses. ip6_address() + Parse an IPv4 or IPv6 address strict. - Parses an IPv4 or IPv6 address string and returns an
+ip4_address() orip6_address() . Does not accept a shortened IPv4 address string.Parses an IPv4 or IPv6 address string and returns an +
or + ip4_address() . + Does not accept a shortened IPv4 address string. ip6_address() + - Return the address and port for the other end of a connection +Return the address and port for the other end of a connection. + - - Returns the address and port for the other end of a - connection. -
-- Note that for SCTP sockets this function only returns - one of the socket's peer addresses. The function -
+peernames/1,2 - returns all. -Returns the address and port for the other end of a connection.
+Notice that for SCTP sockets, this function returns only + one of the peer addresses of the socket. Function +
+ returns all. peernames/1,2 + - - Return all address/port numbers for the other end of a connection - +Return all address/port numbers for the other end of a + connection. - - Equivalent to +
Equivalent to
+. - Note that this function's behaviour for an SCTP + peernames( Socket , 0)Notice that the behavior of this function for an SCTP one-to-many style socket is not defined by the -
+SCTP Sockets API Extensions . -SCTP Sockets API Extensions .+ - - Return all address/port numbers for the other end of a connection - +Return all address/port numbers for the other end of a + connection. - - Returns a list of all address/port number pairs for the other end - of a socket's association
-. - Assoc - This function can return multiple addresses for multihomed - sockets such as SCTP sockets. For other sockets it - returns a one element list. -
-- Note that the
parameter is by the + Assoc Returns a list of all address/port number pairs for the other end + of an association
+of a socket. Assoc This function can return multiple addresses for multihomed + sockets, such as SCTP sockets. For other sockets it + returns a one-element list.
+Notice that parameter
+ one-to-one style sockets. What the special valueis by the Assoc SCTP Sockets API Extensions defined to be ignored for - one-to-one style sockets. What the special value0 - means hence its behaviour for one-to-many style sockets - is unfortunately not defined. -0 + means, hence its behavior for one-to-many style sockets, + is unfortunately undefined.- - Return the local port number for a socket +Return the local port number for a socket. Returns the local port number for a socket.
- -- Return the local address and port number for a socket -- -Returns the local address and port number for a socket.
-- Note that for SCTP sockets this function only returns - one of the socket addresses. The function -
-socknames/1,2 - returns all. -- -- Return all local address/port numbers for a socket -- -- Equivalent to -
-. - socknames( Socket , 0)- +- Return all local address/port numbers for a socket -- -- Returns a list of all local address/port number pairs for a socket - for the given association
-. - Assoc - This function can return multiple addresses for multihomed - sockets such as SCTP sockets. For other sockets it - returns a one element list. -
-- Note that the
-parameter is by the - Assoc SCTP Sockets API Extensions - defined to be ignored for one-to-one style sockets. - For one-to-many style sockets the special value0 - is defined to mean that the returned addresses shall be - without regard to any particular association. - How different SCTP implementations interprets this varies somewhat. -- Set one or more options for a socket +Set one or more options for a socket. - Sets one or more options for a socket. The following options - are available:
+Sets one or more options for a socket.
+The following options are available:
{active, true | false | once | N} - - -
If the value is
+true , which is the default, - everything received from the socket will be sent as - messages to the receiving process. If the value is -false (passive mode), the process must explicitly - receive incoming data by calling + everything received from the socket is sent as + messages to the receiving process.If the value is
false (passive mode), the process must + explicitly receive incoming data by calling, - gen_tcp:recv/2,3 + gen_udp:recv/2,3 , or gen_udp:recv/2,3 (depending on the type of socket). gen_sctp:recv/1,2 If the value is
+ one data message from the socket is sent + to the process. To receive one more message, +once ({active, once} ), - one data message from the socket will be sent - to the process. To receive one more message, -setopts/2 must be called again with the -{active, once} option.setopts/2 must be called again with option +{active, once} .If the value is an integer
N in the range -32768 to 32767 (inclusive), the value is added to the socket's count of data messages sent to the controlling process. A socket's default - message count is 0. If a negative value is specified and its - magnitude is equal to or greater than the socket's current - message count, the socket's message count is set to 0. Once - the socket's message count reaches 0, either due to sending + message count is0 . If a negative value is specified, and + its magnitude is equal to or greater than the socket's current + message count, the socket's message count is set to0 . + Once the socket's message count reaches0 , either because + of sending received data messages to the process or by being explicitly set, the process is then notified by a special message, specific to the type of socket, that the socket has entered passive @@ -575,339 +559,298 @@ fe80::204:acff:fe17:bf38 messagessetopts/2 must be called again to set the socket back into an active mode.When using
-{active, once} or{active, N} , the - socket changes behaviour automatically when data is received. - This can sometimes be confusing in combination with - connection-oriented sockets (i.e.gen_tcp ) as a socket - with{active, false} behaviour reports closing + socket changes behavior automatically when data is received. + This can be confusing in combination with connection-oriented + sockets (that is,gen_tcp ), as a socket + with{active, false} behavior reports closing differently than a socket with{active, true} - behaviour. To make programming easier, a socket where - the peer closed and this was detected while in -{active, false} mode, will still generate the - message + behavior. To simplify programming, a socket where + the peer closed, and this is detected while in +{active, false} mode, still generates message{tcp_closed,Socket} when set to{active, once} , -{active, true} or{active, N} mode. It is therefore - safe to assume that the message -{tcp_closed,Socket} , possibly followed by socket - port termination (depending on theexit_on_close - option) will eventually appear when a socket changes +{active, true} , or{active, N} mode. + It is therefore safe to assume that message +{tcp_closed,Socket} , possibly followed by socket port + termination (depending on optionexit_on_close ) + eventually appears when a socket changes back and forth between{active, true} and{active, false} mode. However, - when peer closing is detected is all up to the + when peer closing is detected it is all up to the underlying TCP/IP stack and protocol.Note that
{active, true} mode provides no flow - control; a fast sender could easily overflow the - receiver with incoming messages. The same is true of -{active, N} mode while the message count is greater - than zero. Use active mode only if +Notice that
+{active, true} mode provides no flow + control; a fast sender can easily overflow the + receiver with incoming messages. The same is true for +{active, N} mode, while the message count is greater + than zero.Use active mode only if your high-level protocol provides its own flow control - (for instance, acknowledging received messages) or the + (for example, acknowledging received messages) or the amount of data exchanged is small.
{active, false} - mode, use of the{active, once} mode or{active, N} + mode, use of the{active, once} mode, or{active, N} mode with values ofN appropriate for the application - provides flow control; the other side will not be able send + provides flow control. The other side cannot send faster than the receiver can read.+ {broadcast, Boolean} (UDP sockets){broadcast, Boolean} (UDP sockets)- -
+Enable/disable permission to send broadcasts.
-+ Enables/disables permission to send broadcasts.
++ + {buffer, Size} - +
- -The size of the user-level software buffer used by + the driver. Not to be confused with options
sndbuf + andrecbuf , which correspond to the +Kernel socket buffers. It is recommended + to haveval(buffer) >= max(val(sndbuf),val(recbuf)) to + avoid performance issues because of unnecessary copying. +val(buffer) is automatically set to the above + maximum when valuessndbuf orrecbuf are set. + However, as the sizes set forsndbuf andrecbuf + usually become larger, you are encouraged to use ++ to analyze the behavior of your operating system. getopts/2 - {buffer, Size} - -
-The size of the user-level software buffer used by - the driver. Not to be confused with
-sndbuf - andrecbuf options which correspond to - the kernel socket buffers. It is recommended - to haveval(buffer) >= max(val(sndbuf),val(recbuf)) to - avoid performance issues due to unnecessary copying. - In fact, theval(buffer) is automatically set to - the above maximum whensndbuf orrecbuf values are set. - However, since the actual sizes set forsndbuf andrecbuf - usually becomes larger, you are encouraged to use -- to analyze the behavior of your operating system. inet:getopts/2 {delay_send, Boolean} - +
Normally, when an Erlang process sends to a socket, - the driver will try to immediately send the data. If that - fails, the driver will use any means available to queue + the driver tries to send the data immediately. If that + fails, the driver uses any means available to queue up the message to be sent whenever the operating system says it can handle it. Setting
+ real property of the socket. The option is + implementation-specific. Defaults to{delay_send, true} - will make all messages queue up. This makes - the messages actually sent onto the network be larger but - fewer. The option actually affects the scheduling of send + makes all messages queue up. The messages sent + to the network are then larger but fewer. + The option affects the scheduling of send requests versus Erlang processes instead of changing any - real property of the socket. Needless to say it is an - implementation specific option. Default isfalse .false . ++ {deliver, port | term} - +
- -When
{active, true} , data is delivered on the form +port :{S, {data, [H1,..Hsz | Data]}} or +term :{tcp, S, [H1..Hsz | Data]} .- {deliver, port | term} - -
When
-{active, true} delivers data on the forms -port :{S, {data, [H1,..Hsz | Data]}} or -term :{tcp, S, [H1..Hsz | Data]} . -{dontroute, Boolean} - -
-Enable/disable routing bypass for outgoing messages.
+Enables/disables routing bypass for outgoing messages.
{exit_on_close, Boolean} - -
-By default this option is set to
+true .This option is set to
true by default.The only reason to set it to
+ to continue sending data to the socket after a close is + detected, for example, if the peer uses +false is if you want - to continue sending data to the socket after a close has - been detected, for instance if the peer has used -gen_tcp:shutdown/2 - to shutdown the write side.+ to shut down the write side. gen_tcp:shutdown/2 {header, Size} - -
-This option is only meaningful if the
binary - option was specified when the socket was created. If - theheader option is specified, the first +This option is only meaningful if option
binary + was specified when the socket was created. If option +header is specified, the firstSize number bytes of data received from the socket - will be elements of a list, and the rest of the data will - be a binary given as the tail of the same list. If for - exampleSize == 2 , the data received will match + are elements of a list, and the remaining data is + a binary specified as the tail of the same list. For example, + ifSize == 2 , the data received matches[Byte1,Byte2|Binary] .{high_msgq_watermark, Size} - -
-The socket message queue will be set into a busy - state when the amount of data queued on the message - queue reaches this limit. Note that this limit only - concerns data that have not yet reached the ERTS internal - socket implementation. Default value used is 8 kB.
-Senders of data to the socket will be suspended if - either the socket message queue is busy, or the socket - itself is busy.
-For more information see the
-low_msgq_watermark , -high_watermark , andlow_watermark options.Note that distribution sockets will disable the use of -
+high_msgq_watermark andlow_msgq_watermark , - and will instead use the -distribution - buffer busy limit which is a similar feature.The socket message queue is set to a busy + state when the amount of data on the message + queue reaches this limit. Notice that this limit only + concerns data that has not yet reached the
+ERTS internal + socket implementation. Defaults to 8 kB.Senders of data to the socket are suspended if + either the socket message queue is busy or the socket + itself is busy.
+For more information, see options
+low_msgq_watermark , +high_watermark , andlow_watermark .Notice that distribution sockets disable the use of +
high_msgq_watermark andlow_msgq_watermark . + Instead use the +distribution buffer busy limit , + which is a similar feature.{high_watermark, Size} (TCP/IP sockets)- -
-The socket will be set into a busy state when the amount - of data queued internally by the ERTS socket implementation - reaches this limit. Default value used is 8 kB.
-Senders of data to the socket will be suspended if - either the socket message queue is busy, or the socket - itself is busy.
-For more information see the
+low_watermark , -high_msgq_watermark , andlow_msqg_watermark - options.The socket is set to a busy state when the amount + of data queued internally by the
+ERTS socket implementation + reaches this limit. Defaults to 8 kB.Senders of data to the socket are suspended if + either the socket message queue is busy or the socket + itself is busy.
+For more information, see options
low_watermark , +high_msgq_watermark , andlow_msqg_watermark .{ipv6_v6only, Boolean} - -
-- Restricts the socket to only use IPv6, prohibiting any +
Restricts the socket to use only IPv6, prohibiting any IPv4 connections. This is only applicable for - IPv6 sockets (option
-inet6 ). -- On most platforms this option has to be set on the socket - before associating it to an address. Therefore it is only - reasonable to give it when creating the socket and not - to use it when calling the function - (
-setopts/2 ) - containing this description. -- The behaviour of a socket with this socket option set to -
+true is becoming the only portable one. The original + IPv6 sockets (optioninet6 ).On most platforms this option must be set on the socket + before associating it to an address. It is therefore only + reasonable to specify it when creating the socket and not + to use it when calling function + (
+) + containing this description. setopts/2 The behavior of a socket with this option set to +
-true is the only portable one. The original idea when IPv6 was new of using IPv6 for all traffic is now not recommended by FreeBSD (you can use{ipv6_v6only,false} to override the recommended system default value), - forbidden by OpenBSD (the supported GENERIC kernel) - and impossible on Windows (that has separate + forbidden by OpenBSD (the supported GENERIC kernel), + and impossible on Windows (which has separate IPv4 and IPv6 protocol stacks). Most Linux distros still have a system default value offalse . - This policy shift among operating systems towards - separating IPv6 from IPv4 traffic has evolved since + This policy shift among operating systems to + separate IPv6 from IPv4 traffic has evolved, as it gradually proved hard and complicated to get - a dual stack implementation correct and secure. -- On some platforms the only allowed value for this option - is
-true , e.g. OpenBSD and Windows. Trying to set - this option tofalse when creating the socket - will in this case fail. -- Setting this option on platforms where it does not exist - is ignored and getting this option with -
-getopts/2 - returns no value i.e the returned list will not contain an -{ipv6_v6only,_} tuple. On Windows the option acually - does not exist, but it is emulated as being a - read-only option with the valuetrue . -- So it boils down to that setting this option to
+true - when creating a socket will never fail except possibly - (at the time of this writing) on a platform where you + a dual stack implementation correct and secure.On some platforms, the only allowed value for this option + is
+true , for example, OpenBSD and Windows. Trying to set + this option tofalse , when creating the socket, fails + in this case.Setting this option on platforms where it does not exist + is ignored. Getting this option with +
++ returns no value, that is, the returned list does not contain an + getopts/2 {ipv6_v6only,_} tuple. On Windows, the option + does not exist, but it is emulated as a + read-only option with valuetrue .Therefore, setting this option to
-true + when creating a socket never fails, except possibly on a + platform where you have customized the kernel to only allowfalse , - which might be doable (but weird) on e.g. OpenBSD. -- If you read back the option value using -
+ which can be doable (but awkward) on, for example, OpenBSD. +getopts/2 - and get no value the option does not exist in the host OS - and all bets are off regarding the behaviour of both - an IPv6 and an IPv4 socket listening on the same port - as well as for an IPv6 socket getting IPv4 traffic. -If you read back the option value using +
+ and get no value, the option does not exist in the host + operating system. The behavior of both an IPv6 and an IPv4 + socket listening on the same port, and for an IPv6 socket + getting IPv4 traffic is then no longer predictable. getopts/2 {keepalive, Boolean} (TCP/IP sockets)- +
Enables/disables periodic transmission on a connected - socket, when no other data is being exchanged. If + socket when no other data is exchanged. If the other end does not respond, the connection is - considered broken and an error message will be sent to - the controlling process. Default disabled.
-+ considered broken and an error message is sent to + the controlling process. Defaults to disabled . ++ + {linger, {true|false, Seconds}} - +
- -Determines the time-out, in seconds, for flushing unsent data + in the
close/1 socket call. If the first component of + the value tuple isfalse , the second is ignored. This + means thatclose/1 returns immediately, not waiting + for data to be flushed. Otherwise, the second component is + the flushing time-out, in seconds.- {linger, {true|false, Seconds}} - -
-Determines the timeout in seconds for flushing unsent data in the -
-close/1 socket call. If the 1st component of the value - tuple isfalse , the 2nd one is ignored, which means that -close/1 returns immediately not waiting - for data to be flushed. Otherwise, the 2nd component is - the flushing time-out in seconds.{low_msgq_watermark, Size} - -
If the socket message queue is in a busy state, the - socket message queue will be set in a not busy state when - the amount of data queued in the message queue falls - below this limit. Note that this limit only concerns data - that have not yet reached the ERTS internal socket - implementation. Default value used is 4 kB.
-Senders that have been suspended due to either a - busy message queue or a busy socket, will be resumed - when neither the socket message queue, nor the socket - are busy.
-For more information see the
-high_msgq_watermark , -high_watermark , andlow_watermark options.Note that distribution sockets will disable the use of -
+ socket message queue is set in a not busy state when + the amount of data queued in the message queue falls + below this limit. Notice that this limit only concerns data + that has not yet reached thehigh_msgq_watermark andlow_msgq_watermark , - and will instead use the -distribution - buffer busy limit which is a similar feature.ERTS internal socket + implementation. Defaults to 4 kB. +Senders that are suspended because of either a + busy message queue or a busy socket are resumed + when the socket message queue and the socket + are not busy.
+For more information, see options
+high_msgq_watermark , +high_watermark , andlow_watermark .Notice that distribution sockets disable the use of +
high_msgq_watermark andlow_msgq_watermark . + Instead they use the +distribution + buffer busy limit , which is a similar feature.{low_watermark, Size} (TCP/IP sockets)- -
- -If the socket is in a busy state, the socket will - be set in a not busy state when the amount of data - queued internally by the ERTS socket implementation - falls below this limit. Default value used is 4 kB.
-Senders that have been suspended due to either a - busy message queue or a busy socket, will be resumed - when neither the socket message queue, nor the socket - are busy.
-For more information see the
+high_watermark , -high_msgq_watermark , andlow_msgq_watermark - options.If the socket is in a busy state, the socket is + set in a not busy state when the amount of data + queued internally by the
+ERTS socket implementation + falls below this limit. Defaults to 4 kB.Senders that are suspended because of a + busy message queue or a busy socket are resumed + when the socket message queue and the socket are not busy.
+For more information, see options
high_watermark , +high_msgq_watermark , andlow_msgq_watermark .+ {mode, Mode :: binary | list} {mode, Mode :: binary | list} - -
- +Received
-Packet is delivered as defined by Mode.Received
+Packet is delivered as defined byMode . +
Set a network namespace for the socket. The
This option uses the Linux specific syscall
-
- The virtual machine also needs elevated privileges either
- running as superuser or (for Linux) having the capability
-
-setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp
-
- Note also that the filesystem containing the virtual machine
- executable (
The
Sets a network namespace for the socket. Parameter
+
This option uses the Linux-specific syscall
+
The virtual machine also needs elevated privileges, either
+ running as superuser or (for Linux) having capability
+
Example:
+
+setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp
+ Notice that the filesystem containing the virtual machine
+ executable (
Emulator flag
Received
Received
Received
Received
If
If
Defines the type of packets to use for a socket. - The following values are valid:
+ Possible values:Packets consist of a header specifying the number of bytes in the packet, followed by that number of bytes. - The length of header can be one, two, or four bytes; + The header length can be one, two, or four bytes, and containing an unsigned integer in big-endian byte order. - Each send operation will generate the header, and the header - will be stripped off on each receive operation.
-In current implementation the 4-byte header is limited to 2Gb.
+ Each send operation generates the header, and the header + is stripped off on each receive operation. +The 4-byte header is limited to 2Gb.
These packet types only have effect on receiving.
When sending a packet, it is the responsibility of
the application to supply a correct header. On
- receiving, however, there will be one message sent to
+ receiving, however, one message is sent to
the controlling process for each complete packet
received, and, similarly, each call to
The meanings of the packet types are as follows:
-
-
-
-
-
-
-
The meanings of the packet types are as follows:
+The Hypertext Transfer Protocol. The packets
are returned with the format according to
These two types are often not needed as the socket will
- automatically switch from
These two types are often not needed, as the socket
+ automatically switches from
Sets the max allowed length of the packet body. If +
Sets the maximum allowed length of the packet body. If the packet header indicates that the length of the packet - is longer than the max allowed length, the packet is - considered invalid. The same happens if the packet header - is too big for the socket receive buffer.
-For line oriented protocols (
For line-oriented protocols (
Sets the line delimiting character for line oriented protocols
- (
Sets the line delimiting character for line-oriented protocols
+ (
Sets the protocol-defined priority for all packets to be sent + on this socket.
+See below.
Set the protocol-defined priority for all packets to be sent - on this socket.
-See below.
-Sets the max number of UDP packets to read without +
Sets the maximum number of UDP packets to read without
intervention from the socket when data is available.
When this many packets have been read and delivered
to the destination process, new packets are not read
until a new notification of available data has arrived.
- The default is 5, and if this parameter is set too
- high the system can become unresponsive due to
+ Defaults to
The minimum size of the receive buffer to use for
the socket. You are encouraged to use
-
Only allowed for connection oriented sockets.
+Only allowed for connection-oriented sockets.
Specifies a longest time to wait for a send operation to
be accepted by the underlying TCP stack. When the limit is
- exceeded, the send operation will return
-
Only allowed for connection oriented sockets.
+Only allowed for connection-oriented sockets.
Used together with
When this option is set to
When this option is set to
Setting this option to
Setting this option to
A connected socket returned from
-
The minimum size of the send buffer to use for the socket.
- You are encouraged to use
-
Sets the SO_PRIORITY socket level option on platforms where - this is implemented. The behaviour and allowed range varies on - different systems. The option is ignored on platforms where the - option is not implemented. Use with caution.
+Sets the
Sets IP_TOS IP level options on platforms where this is - implemented. The behaviour and allowed range varies on different - systems. The option is ignored on platforms where the option is - not implemented. Use with caution.
+Sets
In addition to the options mentioned above, raw +
In addition to these options, raw
option specifications can be used. The raw options are
- specified as a tuple of arity four, beginning with the tag
-
Using raw socket options require detailed knowledge about +
Using raw socket options requires detailed knowledge about the current operating system and TCP stack.
-As an example of the usage of raw options, consider a Linux
- system where you want to set the
Example:
+This example concerns the use of raw options. Consider a Linux
+ system where you want to set option
>}]),]]>
+inet:setopts(Sock,[{raw,6,8,<<30:32/native>>}]),]]>
As many options are silently discarded by the stack if they - are given out of range, it could be a good idea to check that - a raw option really got accepted. This code places the value - in the variable TcpLinger2:
+ are specified out of range; it can be a good idea to check that + a raw option is accepted. The following code places the value + in variable>}]}=inet:getopts(Sock,[{raw,6,8,4}]),]]>
- Code such as the examples above is inherently non portable,
- even different versions of the same OS on the same platform
- may respond differently to this kind of option
+{ok,[{raw,6,8,< Code such as these examples is inherently non-portable,
+ even different versions of the same OS on the same platform
+ can respond differently to this kind of option
manipulation. Use with care. Note that the default options for TCP/IP sockets can be
- changed with the Kernel configuration parameters mentioned in
- the beginning of this document. Notice that the default options for TCP/IP sockets can be
+ changed with the Returns the local address and port number for a socket. Notice that for SCTP sockets this function returns only
+ one of the socket addresses. Function
+ Equivalent to
+ Returns a list of all local address/port number pairs for a socket
+ for the specified association This function can return multiple addresses for multihomed
+ sockets, such as SCTP sockets. For other sockets it
+ returns a one-element list. Notice that parameter See
Returns a If resolver option
+ This address family only works on Unix-like systems.
+
+
+ A
+ Other addresses are possible, for example Linux implements
+ "Abstract Addresses". See the documentation for
+ Unix Domain Sockets on your system,
+ normally
+ In most API functions where you can use
+ this address family the port number must be
+ Addresses besides
+
-
--
cgit v1.2.3
From 348227049f0183854adea2d71d9555fda0ed19c8 Mon Sep 17 00:00:00 2001
From: Hans Bolinder