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Class: Socket::AncillaryData

Relationships & Source Files
Inherits: Object
Defined in: ext/socket/ancdata.c

Overview

AncillaryData represents the ancillary data (control information) used by sendmsg and recvmsg system call. It contains socket #family, control message (cmsg) #level, cmsg #type and cmsg #data.

Class Method Summary

Instance Method Summary

Constructor Details

.new(family, cmsg_level, cmsg_type, cmsg_data) ⇒ AncillaryData

family should be an integer, a string or a symbol.

  • AF_INET, “AF_INET”, “INET”, :AF_INET, :INET

  • AF_UNIX, “AF_UNIX”, “UNIX”, :AF_UNIX, :UNIX

  • etc.

cmsg_level should be an integer, a string or a symbol.

cmsg_type should be an integer, a string or a symbol. If a string/symbol is specified, it is interpreted depend on cmsg_level.

cmsg_data should be a string.

p Socket::AncillaryData.new(:INET, :TCP, :NODELAY, "")
#=> #<Socket::AncillaryData: INET TCP NODELAY "">

p Socket::AncillaryData.new(:INET6, :IPV6, :PKTINFO, "")
#=> #<Socket::AncillaryData: INET6 IPV6 PKTINFO "">

Class Method Details

.int(family, cmsg_level, cmsg_type, integer) ⇒ AncillaryData

Creates a new AncillaryData object which contains a int as data.

The size and endian is dependent on the host.

require 'socket'

p Socket::AncillaryData.int(:UNIX, :SOCKET, :RIGHTS, STDERR.fileno)
#=> #<Socket::AncillaryData: UNIX SOCKET RIGHTS 2>

.ip_pktinfo(addr, ifindex) ⇒ ancdata .ip_pktinfo(addr, ifindex, spec_dst) ⇒ ancdata

Returns new ancillary data for IP_PKTINFO.

If spec_dst is not given, addr is used.

IP_PKTINFO is not standard.

Supported platform: GNU/Linux

addr = Addrinfo.ip("127.0.0.1")
ifindex = 0
spec_dst = Addrinfo.ip("127.0.0.1")
p Socket::AncillaryData.ip_pktinfo(addr, ifindex, spec_dst)
#=> #<Socket::AncillaryData: INET IP PKTINFO 127.0.0.1 ifindex:0 spec_dst:127.0.0.1>

.ipv6_pktinfo(addr, ifindex) ⇒ ancdata

Returns new ancillary data for IPV6_PKTINFO.

IPV6_PKTINFO is defined by RFC 3542.

addr = Addrinfo.ip("::1")
ifindex = 0
p Socket::AncillaryData.ipv6_pktinfo(addr, ifindex)
#=> #<Socket::AncillaryData: INET6 IPV6 PKTINFO ::1 ifindex:0>

.unix_rights(io1, io2, ...) ⇒ AncillaryData

Creates a new AncillaryData object which contains file descriptors as data.

p Socket::AncillaryData.unix_rights(STDERR)
#=> #<Socket::AncillaryData: UNIX SOCKET RIGHTS 2>

Instance Method Details

#cmsg_is?(level, type) ⇒ Boolean

tests the level and type of ancillarydata.

ancdata = Socket::AncillaryData.new(:INET6, :IPV6, :PKTINFO, "")
ancdata.cmsg_is?(Socket::IPPROTO_IPV6, Socket::IPV6_PKTINFO) #=> true
ancdata.cmsg_is?(:IPV6, :PKTINFO)       #=> true
ancdata.cmsg_is?(:IP, :PKTINFO)         #=> false
ancdata.cmsg_is?(:SOCKET, :RIGHTS)      #=> false

#data ⇒ String

returns the cmsg data as a string.

p Socket::AncillaryData.new(:INET6, :IPV6, :PKTINFO, "").data
#=> ""

#family ⇒ Integer

returns the socket family as an integer.

p Socket::AncillaryData.new(:INET6, :IPV6, :PKTINFO, "").family
#=> 10

#inspect ⇒ String

returns a string which shows ancillarydata in human-readable form.

p Socket::AncillaryData.new(:INET6, :IPV6, :PKTINFO, "").inspect
#=> "#<Socket::AncillaryData: INET6 IPV6 PKTINFO \"\">"

#int ⇒ Integer

Returns the data in ancillarydata as an int.

The size and endian is dependent on the host.

ancdata = Socket::AncillaryData.int(:UNIX, :SOCKET, :RIGHTS, STDERR.fileno)
p ancdata.int #=> 2

#ip_pktinfo ⇒ Array, ...

Extracts addr, ifindex and spec_dst from IP_PKTINFO ancillary data.

IP_PKTINFO is not standard.

Supported platform: GNU/Linux

addr = Addrinfo.ip("127.0.0.1")
ifindex = 0
spec_dest = Addrinfo.ip("127.0.0.1")
ancdata = Socket::AncillaryData.ip_pktinfo(addr, ifindex, spec_dest)
p ancdata.ip_pktinfo
#=> [#<Addrinfo: 127.0.0.1>, 0, #<Addrinfo: 127.0.0.1>]

#ipv6_pktinfo ⇒ Array, ifindex

Extracts addr and ifindex from IPV6_PKTINFO ancillary data.

IPV6_PKTINFO is defined by RFC 3542.

addr = Addrinfo.ip("::1")
ifindex = 0
ancdata = Socket::AncillaryData.ipv6_pktinfo(addr, ifindex)
p ancdata.ipv6_pktinfo #=> [#<Addrinfo: ::1>, 0]

#ipv6_pktinfo_addr ⇒ addr

Extracts addr from IPV6_PKTINFO ancillary data.

IPV6_PKTINFO is defined by RFC 3542.

addr = Addrinfo.ip("::1")
ifindex = 0
ancdata = Socket::AncillaryData.ipv6_pktinfo(addr, ifindex)
p ancdata.ipv6_pktinfo_addr #=> #<Addrinfo: ::1>

#ipv6_pktinfo_ifindex ⇒ addr

Extracts ifindex from IPV6_PKTINFO ancillary data.

IPV6_PKTINFO is defined by RFC 3542.

addr = Addrinfo.ip("::1")
ifindex = 0
ancdata = Socket::AncillaryData.ipv6_pktinfo(addr, ifindex)
p ancdata.ipv6_pktinfo_ifindex #=> 0

#level ⇒ Integer

returns the cmsg level as an integer.

p Socket::AncillaryData.new(:INET6, :IPV6, :PKTINFO, "").level
#=> 41

#timestamp ⇒ Time

returns the timestamp as a time object.

ancillarydata should be one of following type:

  • SOL_SOCKET/SCM_TIMESTAMP (microsecond) GNU/Linux, FreeBSD, NetBSD, OpenBSD, Solaris, MacOS X

  • SOL_SOCKET/SCM_TIMESTAMPNS (nanosecond) GNU/Linux

  • SOL_SOCKET/SCM_BINTIME (2**(-64) second) FreeBSD

    Addrinfo.udp(“127.0.0.1”, 0).bind {|s1|

    Addrinfo.udp("127.0.0.1", 0).bind {|s2|
  s1.setsockopt(:SOCKET, :TIMESTAMP, true)
  s2.send "a", 0, s1.local_address
  ctl = s1.recvmsg.last
  p ctl    #=> #<Socket::AncillaryData: INET SOCKET TIMESTAMP 2009-02-24 17:35:46.775581>
  t = ctl.timestamp
  p t      #=> 2009-02-24 17:35:46 +0900
  p t.usec #=> 775581
  p t.nsec #=> 775581000
}

    }

#type ⇒ Integer

returns the cmsg type as an integer.

p Socket::AncillaryData.new(:INET6, :IPV6, :PKTINFO, "").type
#=> 2

#unix_rights ⇒ array-of-IOs?

returns the array of ::IO objects for SCM_RIGHTS control message in UNIX domain socket.

The class of the ::IO objects in the array is ::IO or ::Socket.

The array is attached to ancillarydata when it is instantiated. For example, BasicSocket#recvmsg attach the array when receives a SCM_RIGHTS control message and :scm_rights=>true option is given.

# recvmsg needs :scm_rights=>true for unix_rights
s1, s2 = UNIXSocket.pair
p s1                                         #=> #<UNIXSocket:fd 3>
s1.sendmsg "stdin and a socket", 0, nil, Socket::AncillaryData.unix_rights(STDIN, s1)
_, _, _, ctl = s2.recvmsg(:scm_rights=>true)
p ctl                                        #=> #<Socket::AncillaryData: UNIX SOCKET RIGHTS 6 7>
p ctl.unix_rights                            #=> [#<IO:fd 6>, #<Socket:fd 7>]
p File.identical?(STDIN, ctl.unix_rights[0]) #=> true
p File.identical?(s1, ctl.unix_rights[1])    #=> true

# If :scm_rights=>true is not given, unix_rights returns nil
s1, s2 = UNIXSocket.pair
s1.sendmsg "stdin and a socket", 0, nil, Socket::AncillaryData.unix_rights(STDIN, s1)
_, _, _, ctl = s2.recvmsg
p ctl #=> #<Socket::AncillaryData: UNIX SOCKET RIGHTS 6 7>
p ctl.unix_rights #=> nil