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class Socket

Parent:
BasicSocket

Class Socket provides access to the underlying operating system socket implementations. It can be used to provide more operating system specific functionality than the protocol-specific socket classes.

The constants defined under Socket::Constants are also defined under Socket. For example, Socket::AF_INET is usable as well as Socket::Constants::AF_INET. See Socket::Constants for the list of constants.

What's a socket?

Sockets are endpoints of a bidirectional communication channel. Sockets can communicate within a process, between processes on the same machine or between different machines. There are many types of socket: TCPSocket, UDPSocket or UNIXSocket for example.

Sockets have their own vocabulary:

domain: The family of protocols:

type: The type of communications between the two endpoints, typically

protocol: Typically zero. This may be used to identify a variant of a protocol.

hostname: The identifier of a network interface:

  • a string (hostname, IPv4 or IPv6 address or broadcast which specifies a broadcast address)

  • a zero-length string which specifies INADDR_ANY

  • an integer (interpreted as binary address in host byte order).

Quick start

Many of the classes, such as TCPSocket, UDPSocket or UNIXSocket, ease the use of sockets comparatively to the equivalent C programming interface.

Let's create an internet socket using the IPv4 protocol in a C-like manner:

require 'socket'

s = Socket.new Socket::AF_INET, Socket::SOCK_STREAM
s.connect Socket.pack_sockaddr_in(80, 'example.com')

You could also use the TCPSocket class:

s = TCPSocket.new 'example.com', 80

A simple server might look like this:

require 'socket'

server = TCPServer.new 2000 # Server bound to port 2000

loop do
  client = server.accept    # Wait for a client to connect
  client.puts "Hello !"
  client.puts "Time is #{Time.now}"
  client.close
end

A simple client may look like this:

require 'socket'

s = TCPSocket.new 'localhost', 2000

while line = s.gets # Read lines from socket
  puts line         # and print them
end

s.close             # close socket when done

Exception Handling

Ruby's Socket implementation raises exceptions based on the error generated by the system dependent implementation. This is why the methods are documented in a way that isolate Unix-based system exceptions from Windows based exceptions. If more information on a particular exception is needed, please refer to the Unix manual pages or the Windows WinSock reference.

Convenience methods

Although the general way to create socket is ::new, there are several methods of socket creation for most cases.

TCP client socket

::tcp, IO.open

TCP server socket

::tcp_server_loop, IO.open

UNIX client socket

::unix, IO.open

UNIX server socket

::unix_server_loop, IO.open

Documentation by

  • Zach Dennis

  • Sam Roberts

  • Programming Ruby from The Pragmatic Bookshelf.

Much material in this documentation is taken with permission from Programming Ruby from The Pragmatic Bookshelf.

Constants

AF_APPLETALK

AppleTalk protocol

AF_ATM

Asynchronous Transfer Mode

AF_AX25

AX.25 protocol

AF_CCITT

CCITT (now ITU-T) protocols

AF_CHAOS

MIT CHAOS protocols

AF_CNT

Computer Network Technology

AF_COIP

Connection-oriented IP

AF_DATAKIT

Datakit protocol

AF_DEC

DECnet protocol

AF_DLI

DEC Direct Data Link Interface protocol

AF_E164

CCITT (ITU-T) E.164 recommendation

AF_ECMA

European Computer Manufacturers protocols

NSC Hyperchannel protocol

ARPANET IMP protocol

AF_INET

IPv4 protocol

AF_INET6

IPv6 protocol

AF_IPX

IPX protocol

AF_ISDN

Integrated Services Digital Network

AF_ISO

ISO Open Systems Interconnection protocols

AF_LAT

Local Area Transport protocol

Link layer interface

AF_LOCAL

Host-internal protocols

AF_MAX

Maximum address family for this platform

AF_NATM

Native ATM access

AF_NDRV

Network driver raw access

AF_NETBIOS

NetBIOS

AF_NETGRAPH

Netgraph sockets

AF_NS

XEROX NS protocols

AF_OSI

ISO Open Systems Interconnection protocols

AF_PACKET

Direct link-layer access

AF_PPP

Point-to-Point Protocol

AF_PUP

PARC Universal Packet protocol

AF_ROUTE

Internal routing protocol

AF_SIP

Simple Internet Protocol

AF_SNA

IBM SNA protocol

AF_SYSTEM
AF_UNIX

UNIX sockets

AF_UNSPEC

Unspecified protocol, any supported address family

AI_ADDRCONFIG

Accept only if any address is assigned

AI_ALL

Allow all addresses

AI_CANONNAME

Fill in the canonical name

AI_DEFAULT

Default flags for getaddrinfo

AI_MASK

Valid flag mask for getaddrinfo (not for application use)

AI_NUMERICHOST

Prevent host name resolution

AI_NUMERICSERV

Prevent service name resolution

AI_PASSIVE

Get address to use with bind()

AI_V4MAPPED

Accept IPv4-mapped IPv6 addresses

AI_V4MAPPED_CFG

Accept IPv4 mapped addresses if the kernel supports it

EAI_ADDRFAMILY

Address family for hostname not supported

EAI_AGAIN

Temporary failure in name resolution

EAI_BADFLAGS

Invalid flags

EAI_BADHINTS

Invalid value for hints

EAI_FAIL

Non-recoverable failure in name resolution

EAI_FAMILY

Address family not supported

EAI_MAX

Maximum error code from getaddrinfo

EAI_MEMORY

Memory allocation failure

EAI_NODATA

No address associated with hostname

EAI_NONAME

Hostname nor servname, or not known

EAI_OVERFLOW

Argument buffer overflow

EAI_PROTOCOL

Resolved protocol is unknown

EAI_SERVICE

Servname not supported for socket type

EAI_SOCKTYPE

Socket type not supported

EAI_SYSTEM

System error returned in errno

IFF_802_1Q_VLAN

802.1Q VLAN device

IFF_ALLMULTI

receive all multicast packets

IFF_ALTPHYS

use alternate physical connection

IFF_AUTOMEDIA

auto media select active

IFF_BONDING

bonding master or slave

IFF_BRIDGE_PORT

device used as bridge port

IFF_BROADCAST

broadcast address valid

IFF_CANTCHANGE

flags not changeable

IFF_CANTCONFIG

unconfigurable using ioctl(2)

IFF_DEBUG

turn on debugging

IFF_DISABLE_NETPOLL

disable netpoll at run-time

IFF_DONT_BRIDGE

disallow bridging this ether dev

IFF_DORMANT

driver signals dormant

IFF_DRV_OACTIVE

tx hardware queue is full

IFF_DRV_RUNNING

resources allocated

IFF_DYING

interface is winding down

IFF_DYNAMIC

dialup device with changing addresses

IFF_EBRIDGE

ethernet bridging device

IFF_ECHO

echo sent packets

IFF_ISATAP

ISATAP interface (RFC4214)

IFF_LINK0

per link layer defined bit 0

IFF_LINK1

per link layer defined bit 1

IFF_LINK2

per link layer defined bit 2

IFF_LIVE_ADDR_CHANGE

hardware address change when it's running

IFF_LOOPBACK

loopback net

IFF_LOWER_UP

driver signals L1 up

IFF_MACVLAN_PORT

device used as macvlan port

IFF_MASTER

master of a load balancer

IFF_MASTER_8023AD

bonding master, 802.3ad.

IFF_MASTER_ALB

bonding master, balance-alb.

IFF_MASTER_ARPMON

bonding master, ARP mon in use

IFF_MONITOR

user-requested monitor mode

IFF_MULTICAST

supports multicast

IFF_NOARP

no address resolution protocol

IFF_NOTRAILERS

avoid use of trailers

IFF_OACTIVE

transmission in progress

IFF_OVS_DATAPATH

device used as Open vSwitch datapath port

IFF_POINTOPOINT

point-to-point link

IFF_PORTSEL

can set media type

IFF_PPROMISC

user-requested promisc mode

IFF_PROMISC

receive all packets

IFF_RENAMING

interface is being renamed

IFF_ROUTE

routing entry installed

IFF_RUNNING

resources allocated

IFF_SIMPLEX

can't hear own transmissions

IFF_SLAVE

slave of a load balancer

IFF_SLAVE_INACTIVE

bonding slave not the curr. active

IFF_SLAVE_NEEDARP

need ARPs for validation

IFF_SMART

interface manages own routes

IFF_STATICARP

static ARP

IFF_SUPP_NOFCS

sending custom FCS

IFF_TEAM_PORT

used as team port

IFF_TX_SKB_SHARING

sharing skbs on transmit

IFF_UNICAST_FLT

unicast filtering

IFF_UP

interface is up

IFF_VOLATILE

volatile flags

IFF_WAN_HDLC

WAN HDLC device

IFF_XMIT_DST_RELEASE

dev_hard_start_xmit() is allowed to release skb->dst

IFNAMSIZ

Maximum interface name size

IF_NAMESIZE

Maximum interface name size

INADDR_ALLHOSTS_GROUP

Multicast group for all systems on this subset

INADDR_ANY

A socket bound to INADDR_ANY receives packets from all interfaces and sends from the default IP address

INADDR_BROADCAST

The network broadcast address

INADDR_LOOPBACK

The loopback address

INADDR_MAX_LOCAL_GROUP

The last local network multicast group

INADDR_NONE

A bitmask for matching no valid IP address

INADDR_UNSPEC_GROUP

The reserved multicast group

INET6_ADDRSTRLEN

Maximum length of an IPv6 address string

INET_ADDRSTRLEN

Maximum length of an IPv4 address string

IPPORT_RESERVED

Default minimum address for bind or connect

IPPORT_USERRESERVED

Default maximum address for bind or connect

IPPROTO_AH

IP6 auth header

IPPROTO_BIP
IPPROTO_DSTOPTS

IP6 destination option

IPPROTO_EGP

Exterior Gateway Protocol

IPPROTO_EON

ISO cnlp

IPPROTO_ESP

IP6 Encapsulated Security Payload

IPPROTO_FRAGMENT

IP6 fragmentation header

IPPROTO_GGP

Gateway to Gateway Protocol

IPPROTO_HELLO

“hello” routing protocol

IPPROTO_HOPOPTS

IP6 hop-by-hop options

IPPROTO_ICMP

Control message protocol

IPPROTO_ICMPV6

ICMP6

IPPROTO_IDP

XNS IDP

IPPROTO_IGMP

Group Management Protocol

IPPROTO_IP

Dummy protocol for IP

IPPROTO_IPV6

IP6 header

IPPROTO_MAX

Maximum IPPROTO constant

IPPROTO_ND

Sun net disk protocol

IPPROTO_NONE

IP6 no next header

IPPROTO_PUP

PARC Universal Packet protocol

IPPROTO_RAW

Raw IP packet

IPPROTO_ROUTING

IP6 routing header

IPPROTO_TCP

TCP

IPPROTO_TP

ISO transport protocol class 4

IPPROTO_UDP

UDP

IPPROTO_XTP

Xpress Transport Protocol

IPV6_CHECKSUM

Checksum offset for raw sockets

IPV6_DONTFRAG

Don't fragment packets

IPV6_DSTOPTS

Destination option

IPV6_HOPLIMIT

Hop limit

IPV6_HOPOPTS

Hop-by-hop option

IPV6_JOIN_GROUP

Join a group membership

IPV6_LEAVE_GROUP

Leave a group membership

IPV6_MULTICAST_HOPS

IP6 multicast hops

IPV6_MULTICAST_IF

IP6 multicast interface

IPV6_MULTICAST_LOOP

IP6 multicast loopback

IPV6_NEXTHOP

Next hop address

IPV6_PATHMTU

Retrieve current path MTU

IPV6_PKTINFO

Receive packet information with datagram

IPV6_RECVDSTOPTS

Receive all IP6 options for response

IPV6_RECVHOPLIMIT

Receive hop limit with datagram

IPV6_RECVHOPOPTS

Receive hop-by-hop options

IPV6_RECVPATHMTU

Receive current path MTU with datagram

IPV6_RECVPKTINFO

Receive destination IP address and incoming interface

IPV6_RECVRTHDR

Receive routing header

IPV6_RECVTCLASS

Receive traffic class

IPV6_RTHDR

Allows removal of sticky routing headers

IPV6_RTHDRDSTOPTS

Allows removal of sticky destination options header

IPV6_RTHDR_TYPE_0

Routing header type 0

IPV6_TCLASS

Specify the traffic class

IPV6_UNICAST_HOPS

IP6 unicast hops

IPV6_USE_MIN_MTU

Use the minimum MTU size

IPV6_V6ONLY

Only bind IPv6 with a wildcard bind

IPX_TYPE
IP_ADD_MEMBERSHIP

Add a multicast group membership

IP_ADD_SOURCE_MEMBERSHIP

Add a multicast group membership

IP_BLOCK_SOURCE

Block IPv4 multicast packets with a give source address

IP_DEFAULT_MULTICAST_LOOP

Default multicast loopback

IP_DEFAULT_MULTICAST_TTL

Default multicast TTL

IP_DONTFRAG

Don't fragment packets

IP_DROP_MEMBERSHIP

Drop a multicast group membership

IP_DROP_SOURCE_MEMBERSHIP

Drop a multicast group membership

IP_FREEBIND

Allow binding to nonexistent IP addresses

IP_HDRINCL

Header is included with data

IP_IPSEC_POLICY

IPsec security policy

IP_MAX_MEMBERSHIPS

Maximum number multicast groups a socket can join

IP_MINTTL

Minimum TTL allowed for received packets

IP_MSFILTER

Multicast source filtering

IP_MTU

The Maximum Transmission Unit of the socket

IP_MTU_DISCOVER

Path MTU discovery

IP_MULTICAST_IF

IP multicast interface

IP_MULTICAST_LOOP

IP multicast loopback

IP_MULTICAST_TTL

IP multicast TTL

IP_ONESBCAST

Force outgoing broadcast datagrams to have the undirected broadcast address

IP_OPTIONS

IP options to be included in packets

IP_PASSSEC

Retrieve security context with datagram

IP_PKTINFO

Receive packet information with datagrams

IP_PKTOPTIONS

Receive packet options with datagrams

IP_PMTUDISC_DO

Always send DF frames

IP_PMTUDISC_DONT

Never send DF frames

IP_PMTUDISC_WANT

Use per-route hints

IP_PORTRANGE

Set the port range for sockets with unspecified port numbers

IP_RECVDSTADDR

Receive IP destination address with datagram

IP_RECVERR

Enable extended reliable error message passing

IP_RECVIF

Receive interface information with datagrams

IP_RECVOPTS

Receive all IP options with datagram

IP_RECVRETOPTS

Receive all IP options for response

IP_RECVSLLA

Receive link-layer address with datagrams

IP_RECVTOS

Receive TOS with incoming packets

IP_RECVTTL

Receive IP TTL with datagrams

IP_RETOPTS

IP options to be included in datagrams

IP_ROUTER_ALERT

Notify transit routers to more closely examine the contents of an IP packet

IP_SENDSRCADDR

Source address for outgoing UDP datagrams

IP_TOS

IP type-of-service

IP_TRANSPARENT

Transparent proxy

IP_TTL

IP time-to-live

IP_UNBLOCK_SOURCE

Unblock IPv4 multicast packets with a give source address

IP_XFRM_POLICY
LOCAL_CONNWAIT

Connect blocks until accepted

LOCAL_CREDS

Pass credentials to receiver

LOCAL_PEERCRED

Retrieve peer credentials

MCAST_BLOCK_SOURCE

Block multicast packets from this source

MCAST_EXCLUDE

Exclusive multicast source filter

MCAST_INCLUDE

Inclusive multicast source filter

MCAST_JOIN_GROUP

Join a multicast group

MCAST_JOIN_SOURCE_GROUP

Join a multicast source group

MCAST_LEAVE_GROUP

Leave a multicast group

MCAST_LEAVE_SOURCE_GROUP

Leave a multicast source group

MCAST_MSFILTER

Multicast source filtering

MCAST_UNBLOCK_SOURCE

Unblock multicast packets from this source

MSG_COMPAT

End of record

MSG_CONFIRM

Confirm path validity

MSG_CTRUNC

Control data lost before delivery

MSG_DONTROUTE

Send without using the routing tables

MSG_DONTWAIT

This message should be non-blocking

MSG_EOF

Data completes connection

MSG_EOR

Data completes record

MSG_ERRQUEUE

Fetch message from error queue

MSG_FASTOPEN

Reduce step of the handshake process

MSG_FIN
MSG_FLUSH

Start of a hold sequence. Dumps to so_temp

MSG_HAVEMORE

Data ready to be read

MSG_HOLD

Hold fragment in so_temp

MSG_MORE

Sender will send more

MSG_NOSIGNAL

Do not generate SIGPIPE

MSG_OOB

Process out-of-band data

MSG_PEEK

Peek at incoming message

MSG_PROXY

Wait for full request

MSG_RCVMORE

Data remains in the current packet

MSG_RST
MSG_SEND

Send the packet in so_temp

MSG_SYN
MSG_TRUNC

Data discarded before delivery

MSG_WAITALL

Wait for full request or error

NI_DGRAM

The service specified is a datagram service (looks up UDP ports)

NI_MAXHOST

Maximum length of a hostname

NI_MAXSERV

Maximum length of a service name

NI_NAMEREQD

A name is required

NI_NOFQDN

An FQDN is not required for local hosts, return only the local part

NI_NUMERICHOST

Return a numeric address

NI_NUMERICSERV

Return the service name as a digit string

PF_APPLETALK

AppleTalk protocol

PF_ATM

Asynchronous Transfer Mode

PF_AX25

AX.25 protocol

PF_CCITT

CCITT (now ITU-T) protocols

PF_CHAOS

MIT CHAOS protocols

PF_CNT

Computer Network Technology

PF_COIP

Connection-oriented IP

PF_DATAKIT

Datakit protocol

PF_DEC

DECnet protocol

PF_DLI

DEC Direct Data Link Interface protocol

PF_ECMA

European Computer Manufacturers protocols

NSC Hyperchannel protocol

ARPANET IMP protocol

PF_INET

IPv4 protocol

PF_INET6

IPv6 protocol

PF_IPX

IPX protocol

PF_ISDN

Integrated Services Digital Network

PF_ISO

ISO Open Systems Interconnection protocols

PF_KEY
PF_LAT

Local Area Transport protocol

Link layer interface

PF_LOCAL

Host-internal protocols

PF_MAX

Maximum address family for this platform

PF_NATM

Native ATM access

PF_NDRV

Network driver raw access

PF_NETBIOS

NetBIOS

PF_NETGRAPH

Netgraph sockets

PF_NS

XEROX NS protocols

PF_OSI

ISO Open Systems Interconnection protocols

PF_PACKET

Direct link-layer access

PF_PIP
PF_PPP

Point-to-Point Protocol

PF_PUP

PARC Universal Packet protocol

PF_ROUTE

Internal routing protocol

PF_RTIP
PF_SIP

Simple Internet Protocol

PF_SNA

IBM SNA protocol

PF_SYSTEM
PF_UNIX

UNIX sockets

PF_UNSPEC

Unspecified protocol, any supported address family

PF_XTP

eXpress Transfer Protocol

SCM_BINTIME

Timestamp (bintime)

SCM_CREDENTIALS

The sender's credentials

SCM_CREDS

Process credentials

SCM_RIGHTS

Access rights

SCM_TIMESTAMP

Timestamp (timeval)

SCM_TIMESTAMPING

Timestamp (timespec list) (Linux 2.6.30)

SCM_TIMESTAMPNS

Timespec (timespec)

SCM_UCRED

User credentials

SCM_WIFI_STATUS

Wifi status (Linux 3.3)

SHUT_RD

Shut down the reading side of the socket

SHUT_RDWR

Shut down the both sides of the socket

SHUT_WR

Shut down the writing side of the socket

SOCK_DGRAM

A datagram socket provides connectionless, unreliable messaging

SOCK_PACKET

Device-level packet access

SOCK_RAW

A raw socket provides low-level access for direct access or implementing network protocols

SOCK_RDM

A reliable datagram socket provides reliable delivery of messages

SOCK_SEQPACKET

A sequential packet socket provides sequenced, reliable two-way connection for datagrams

SOCK_STREAM

A stream socket provides a sequenced, reliable two-way connection for a byte stream

SOL_ATALK

AppleTalk socket options

SOL_AX25

AX.25 socket options

SOL_IP

IP socket options

SOL_IPX

IPX socket options

SOL_SOCKET

Socket-level options

SOL_TCP

TCP socket options

SOL_UDP

UDP socket options

SOMAXCONN

Maximum connection requests that may be queued for a socket

SOPRI_BACKGROUND

Background socket priority

SOPRI_INTERACTIVE

Interactive socket priority

SOPRI_NORMAL

Normal socket priority

SO_ACCEPTCONN

Socket has had listen() called on it

SO_ACCEPTFILTER

There is an accept filter

SO_ALLZONES

Bypass zone boundaries

SO_ATTACH_FILTER

Attach an accept filter

SO_BINDTODEVICE

Only send packets from the given interface

SO_BINTIME

Receive timestamp with datagrams (bintime)

SO_BPF_EXTENSIONS

Query supported BPF extensions (Linux 3.14)

SO_BROADCAST

Permit sending of broadcast messages

SO_BUSY_POLL

Set the threshold in microseconds for low latency polling (Linux 3.11)

SO_DEBUG

Debug info recording

SO_DETACH_FILTER

Detach an accept filter

SO_DOMAIN

Domain given for socket() (Linux 2.6.32)

SO_DONTROUTE

Use interface addresses

SO_DONTTRUNC

Retain unread data

SO_ERROR

Get and clear the error status

SO_GET_FILTER

Obtain filter set by SO_ATTACH_FILTER (Linux 3.8)

SO_KEEPALIVE

Keep connections alive

SO_LINGER

Linger on close if data is present

SO_LOCK_FILTER

Lock the filter attached to a socket (Linux 3.9)

SO_MAC_EXEMPT

Mandatory Access Control exemption for unlabeled peers

SO_MARK

Set the mark for mark-based routing (Linux 2.6.25)

SO_MAX_PACING_RATE

Cap the rate computed by transport layer. [bytes per second] (Linux 3.13)

SO_NKE

Install socket-level Network Kernel Extension

SO_NOFCS

Set netns of a socket (Linux 3.4)

SO_NOSIGPIPE

Don't SIGPIPE on EPIPE

SO_NO_CHECK

Disable checksums

SO_NREAD

Get first packet byte count

SO_OOBINLINE

Leave received out-of-band data in-line

SO_PASSCRED

Receive SCM_CREDENTIALS messages

SO_PASSSEC

Toggle security context passing (Linux 2.6.18)

SO_PEEK_OFF

Set the peek offset (Linux 3.4)

SO_PEERCRED

The credentials of the foreign process connected to this socket

SO_PEERNAME

Name of the connecting user

SO_PEERSEC

Obtain the security credentials (Linux 2.6.2)

SO_PRIORITY

The protocol-defined priority for all packets on this socket

SO_PROTOCOL

Protocol given for socket() (Linux 2.6.32)

SO_RCVBUF

Receive buffer size

SO_RCVBUFFORCE

Receive buffer size without rmem_max limit (Linux 2.6.14)

SO_RCVLOWAT

Receive low-water mark

SO_RCVTIMEO

Receive timeout

SO_RECVUCRED

Receive user credentials with datagram

SO_REUSEADDR

Allow local address reuse

SO_REUSEPORT

Allow local address and port reuse

SO_RXQ_OVFL

Toggle cmsg for number of packets dropped (Linux 2.6.33)

SO_SECURITY_AUTHENTICATION
SO_SECURITY_ENCRYPTION_NETWORK
SO_SECURITY_ENCRYPTION_TRANSPORT
SO_SELECT_ERR_QUEUE

Make select() detect socket error queue with errorfds (Linux 3.10)

SO_SNDBUF

Send buffer size

SO_SNDBUFFORCE

Send buffer size without wmem_max limit (Linux 2.6.14)

SO_SNDLOWAT

Send low-water mark

SO_SNDTIMEO

Send timeout

SO_TIMESTAMP

Receive timestamp with datagrams (timeval)

SO_TIMESTAMPING

Time stamping of incoming and outgoing packets (Linux 2.6.30)

SO_TIMESTAMPNS

Receive nanosecond timestamp with datagrams (timespec)

SO_TYPE

Get the socket type

SO_USELOOPBACK

Bypass hardware when possible

SO_WANTMORE

Give a hint when more data is ready

SO_WANTOOBFLAG

OOB data is wanted in MSG_FLAG on receive

SO_WIFI_STATUS

Toggle cmsg for wifi status (Linux 3.3)

TCP_CONGESTION

TCP congestion control algorithm (Linux 2.6.13, glibc 2.6)

TCP Cookie Transactions (Linux 2.6.33, glibc 2.18)

TCP_CORK

Don't send partial frames (Linux 2.2, glibc 2.2)

TCP_DEFER_ACCEPT

Don't notify a listening socket until data is ready (Linux 2.4, glibc 2.2)

TCP_FASTOPEN

Reduce step of the handshake process (Linux 3.7, glibc 2.18)

TCP_INFO

Retrieve information about this socket (Linux 2.4, glibc 2.2)

TCP_KEEPCNT

Maximum number of keepalive probes allowed before dropping a connection (Linux 2.4, glibc 2.2)

TCP_KEEPIDLE

Idle time before keepalive probes are sent (Linux 2.4, glibc 2.2)

TCP_KEEPINTVL

Time between keepalive probes (Linux 2.4, glibc 2.2)

TCP_LINGER2

Lifetime of orphaned FIN_WAIT2 sockets (Linux 2.4, glibc 2.2)

TCP_MAXSEG

Set maximum segment size

TCP_MD5SIG

Use MD5 digests (RFC2385, Linux 2.6.20, glibc 2.7)

TCP_NODELAY

Don't delay sending to coalesce packets

TCP_NOOPT

Don't use TCP options

TCP_NOPUSH

Don't push the last block of write

TCP_QUEUE_SEQ

Sequence of a queue for repair mode (Linux 3.5, glibc 2.18)

TCP_QUICKACK

Enable quickack mode (Linux 2.4.4, glibc 2.3)

TCP_REPAIR

Repair mode (Linux 3.5, glibc 2.18)

TCP_REPAIR_OPTIONS

Options for repair mode (Linux 3.5, glibc 2.18)

TCP_REPAIR_QUEUE

Queue for repair mode (Linux 3.5, glibc 2.18)

TCP_SYNCNT

Number of SYN retransmits before a connection is dropped (Linux 2.4, glibc 2.2)

TCP_THIN_DUPACK

Duplicated acknowledgments handling for thin-streams (Linux 2.6.34, glibc 2.18)

TCP_THIN_LINEAR_TIMEOUTS

Linear timeouts for thin-streams (Linux 2.6.34, glibc 2.18)

TCP_TIMESTAMP

TCP timestamp (Linux 3.9, glibc 2.18)

TCP_USER_TIMEOUT

Max timeout before a TCP connection is aborted (Linux 2.6.37, glibc 2.18)

TCP_WINDOW_CLAMP

Clamp the size of the advertised window (Linux 2.4, glibc 2.2)

UDP_CORK

Don't send partial frames (Linux 2.5.44, glibc 2.11)

Public Class Methods

accept_loop(*sockets) { |socket, client_addrinfo| ... } Show source

yield socket and client address for each a connection accepted via given sockets.

The arguments are a list of sockets. The individual argument should be a socket or an array of sockets.

This method yields the block sequentially. It means that the next connection is not accepted until the block returns. So concurrent mechanism, thread for example, should be used to service multiple clients at a time.

# File ext/socket/lib/socket.rb, line 784
def self.accept_loop(*sockets) # :yield: socket, client_addrinfo
  sockets.flatten!(1)
  if sockets.empty?
    raise ArgumentError, "no sockets"
  end
  loop {
    readable, _, _ = IO.select(sockets)
    readable.each {|r|
      sock, addr = r.accept_nonblock(exception: false)
      next if sock == :wait_readable
      yield sock, addr
    }
  }
end
getaddrinfo(nodename, servname[, family[, socktype[, protocol[, flags[, reverse_lookup]]]]]) → array Show source

Obtains address information for nodename:servname.

family should be an address family such as: :INET, :INET6, etc.

socktype should be a socket type such as: :STREAM, :DGRAM, :RAW, etc.

protocol should be a protocol defined in the family, and defaults to 0 for the family.

flags should be bitwise OR of Socket::AI_* constants.

Socket.getaddrinfo("www.ruby-lang.org", "http", nil, :STREAM)
#=> [["AF_INET", 80, "carbon.ruby-lang.org", "221.186.184.68", 2, 1, 6]] # PF_INET/SOCK_STREAM/IPPROTO_TCP

Socket.getaddrinfo("localhost", nil)
#=> [["AF_INET", 0, "localhost", "127.0.0.1", 2, 1, 6],  # PF_INET/SOCK_STREAM/IPPROTO_TCP
#    ["AF_INET", 0, "localhost", "127.0.0.1", 2, 2, 17], # PF_INET/SOCK_DGRAM/IPPROTO_UDP
#    ["AF_INET", 0, "localhost", "127.0.0.1", 2, 3, 0]]  # PF_INET/SOCK_RAW/IPPROTO_IP

reverse_lookup directs the form of the third element, and has to be one of below. If reverse_lookup is omitted, the default value is nil.

+true+, +:hostname+:  hostname is obtained from numeric address using reverse lookup, which may take a time.
+false+, +:numeric+:  hostname is same as numeric address.
+nil+:              obey to the current +do_not_reverse_lookup+ flag.

If Addrinfo object is preferred, use Addrinfo.getaddrinfo.

static VALUE
sock_s_getaddrinfo(int argc, VALUE *argv)
{
    VALUE host, port, family, socktype, protocol, flags, ret, revlookup;
    struct addrinfo hints;
    struct rb_addrinfo *res;
    int norevlookup;

    rb_scan_args(argc, argv, "25", &host, &port, &family, &socktype, &protocol, &flags, &revlookup);

    MEMZERO(&hints, struct addrinfo, 1);
    hints.ai_family = NIL_P(family) ? PF_UNSPEC : rsock_family_arg(family);

    if (!NIL_P(socktype)) {
        hints.ai_socktype = rsock_socktype_arg(socktype);
    }
    if (!NIL_P(protocol)) {
        hints.ai_protocol = NUM2INT(protocol);
    }
    if (!NIL_P(flags)) {
        hints.ai_flags = NUM2INT(flags);
    }
    if (NIL_P(revlookup) || !rsock_revlookup_flag(revlookup, &norevlookup)) {
        norevlookup = rsock_do_not_reverse_lookup;
    }
    res = rsock_getaddrinfo(host, port, &hints, 0);

    ret = make_addrinfo(res, norevlookup);
    rb_freeaddrinfo(res);
    return ret;
}
gethostbyaddr(address_string [, address_family]) → hostent Show source

Obtains the host information for address.

p Socket.gethostbyaddr([221,186,184,68].pack("CCCC"))
#=> ["carbon.ruby-lang.org", [], 2, "\xDD\xBA\xB8D"]
static VALUE
sock_s_gethostbyaddr(int argc, VALUE *argv)
{
    VALUE addr, family;
    struct hostent *h;
    char **pch;
    VALUE ary, names;
    int t = AF_INET;

    rb_scan_args(argc, argv, "11", &addr, &family);
    StringValue(addr);
    if (!NIL_P(family)) {
        t = rsock_family_arg(family);
    }
#ifdef AF_INET6
    else if (RSTRING_LEN(addr) == 16) {
        t = AF_INET6;
    }
#endif
    h = gethostbyaddr(RSTRING_PTR(addr), RSTRING_SOCKLEN(addr), t);
    if (h == NULL) {
#ifdef HAVE_HSTRERROR
        extern int h_errno;
        rb_raise(rb_eSocket, "%s", (char*)hstrerror(h_errno));
#else
        rb_raise(rb_eSocket, "host not found");
#endif
    }
    ary = rb_ary_new();
    rb_ary_push(ary, rb_str_new2(h->h_name));
    names = rb_ary_new();
    rb_ary_push(ary, names);
    if (h->h_aliases != NULL) {
        for (pch = h->h_aliases; *pch; pch++) {
            rb_ary_push(names, rb_str_new2(*pch));
        }
    }
    rb_ary_push(ary, INT2NUM(h->h_addrtype));
#ifdef h_addr
    for (pch = h->h_addr_list; *pch; pch++) {
        rb_ary_push(ary, rb_str_new(*pch, h->h_length));
    }
#else
    rb_ary_push(ary, rb_str_new(h->h_addr, h->h_length));
#endif

    return ary;
}
gethostbyname(hostname) → [official_hostname, alias_hostnames, address_family, *address_list] Show source

Obtains the host information for hostname.

p Socket.gethostbyname("hal") #=> ["localhost", ["hal"], 2, "\x7F\x00\x00\x01"]
static VALUE
sock_s_gethostbyname(VALUE obj, VALUE host)
{
    struct rb_addrinfo *res =
        rsock_addrinfo(host, Qnil, AF_UNSPEC, SOCK_STREAM, AI_CANONNAME);
    return rsock_make_hostent(host, res, sock_sockaddr);
}
gethostname → hostname Show source

Returns the hostname.

p Socket.gethostname #=> "hal"

Note that it is not guaranteed to be able to convert to IP address using gethostbyname, getaddrinfo, etc. If you need local IP address, use ::ip_address_list.

static VALUE
sock_gethostname(VALUE obj)
{
#if defined(NI_MAXHOST)
#  define RUBY_MAX_HOST_NAME_LEN NI_MAXHOST
#elif defined(HOST_NAME_MAX)
#  define RUBY_MAX_HOST_NAME_LEN HOST_NAME_MAX
#else
#  define RUBY_MAX_HOST_NAME_LEN 1024
#endif

    long len = RUBY_MAX_HOST_NAME_LEN;
    VALUE name;

    name = rb_str_new(0, len);
    while (gethostname(RSTRING_PTR(name), len) < 0) {
        int e = errno;
        switch (e) {
          case ENAMETOOLONG:
#ifdef __linux__
          case EINVAL:
            /* glibc before version 2.1 uses EINVAL instead of ENAMETOOLONG */
#endif
            break;
          default:
            rb_syserr_fail(e, "gethostname(3)");
        }
        rb_str_modify_expand(name, len);
        len += len;
    }
    rb_str_resize(name, strlen(RSTRING_PTR(name)));
    return name;
}
getifaddrs → [ifaddr1, ...] Show source

Returns an array of interface addresses. An element of the array is an instance of Socket::Ifaddr.

This method can be used to find multicast-enabled interfaces:

pp Socket.getifaddrs.reject {|ifaddr|
  !ifaddr.addr.ip? || (ifaddr.flags & Socket::IFF_MULTICAST == 0)
}.map {|ifaddr| [ifaddr.name, ifaddr.ifindex, ifaddr.addr] }
#=> [["eth0", 2, #<Addrinfo: 221.186.184.67>],
#    ["eth0", 2, #<Addrinfo: fe80::216:3eff:fe95:88bb%eth0>]]

Example result on GNU/Linux:

pp Socket.getifaddrs
#=> [#<Socket::Ifaddr lo UP,LOOPBACK,RUNNING,0x10000 PACKET[protocol=0 lo hatype=772 HOST hwaddr=00:00:00:00:00:00]>,
#    #<Socket::Ifaddr eth0 UP,BROADCAST,RUNNING,MULTICAST,0x10000 PACKET[protocol=0 eth0 hatype=1 HOST hwaddr=00:16:3e:95:88:bb] broadcast=PACKET[protocol=0 eth0 hatype=1 HOST hwaddr=ff:ff:ff:ff:ff:ff]>,
#    #<Socket::Ifaddr sit0 NOARP PACKET[protocol=0 sit0 hatype=776 HOST hwaddr=00:00:00:00]>,
#    #<Socket::Ifaddr lo UP,LOOPBACK,RUNNING,0x10000 127.0.0.1 netmask=255.0.0.0>,
#    #<Socket::Ifaddr eth0 UP,BROADCAST,RUNNING,MULTICAST,0x10000 221.186.184.67 netmask=255.255.255.240 broadcast=221.186.184.79>,
#    #<Socket::Ifaddr lo UP,LOOPBACK,RUNNING,0x10000 ::1 netmask=ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff>,
#    #<Socket::Ifaddr eth0 UP,BROADCAST,RUNNING,MULTICAST,0x10000 fe80::216:3eff:fe95:88bb%eth0 netmask=ffff:ffff:ffff:ffff::>]

Example result on FreeBSD:

pp Socket.getifaddrs
#=> [#<Socket::Ifaddr usbus0 UP,0x10000 LINK[usbus0]>,
#    #<Socket::Ifaddr re0 UP,BROADCAST,RUNNING,MULTICAST,0x800 LINK[re0 3a:d0:40:9a:fe:e8]>,
#    #<Socket::Ifaddr re0 UP,BROADCAST,RUNNING,MULTICAST,0x800 10.250.10.18 netmask=255.255.255.? (7 bytes for 16 bytes sockaddr_in) broadcast=10.250.10.255>,
#    #<Socket::Ifaddr re0 UP,BROADCAST,RUNNING,MULTICAST,0x800 fe80:2::38d0:40ff:fe9a:fee8 netmask=ffff:ffff:ffff:ffff::>,
#    #<Socket::Ifaddr re0 UP,BROADCAST,RUNNING,MULTICAST,0x800 2001:2e8:408:10::12 netmask=UNSPEC>,
#    #<Socket::Ifaddr plip0 POINTOPOINT,MULTICAST,0x800 LINK[plip0]>,
#    #<Socket::Ifaddr lo0 UP,LOOPBACK,RUNNING,MULTICAST LINK[lo0]>,
#    #<Socket::Ifaddr lo0 UP,LOOPBACK,RUNNING,MULTICAST ::1 netmask=ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff>,
#    #<Socket::Ifaddr lo0 UP,LOOPBACK,RUNNING,MULTICAST fe80:4::1 netmask=ffff:ffff:ffff:ffff::>,
#    #<Socket::Ifaddr lo0 UP,LOOPBACK,RUNNING,MULTICAST 127.0.0.1 netmask=255.?.?.? (5 bytes for 16 bytes sockaddr_in)>]
static VALUE
socket_s_getifaddrs(VALUE self)
{
    return rsock_getifaddrs();
}
getnameinfo(sockaddr [, flags]) → [hostname, servicename] Show source

Obtains name information for sockaddr.

sockaddr should be one of follows.

  • packed sockaddr string such as ::sockaddr_in(80, “127.0.0.1”)

  • 3-elements array such as [“AF_INET”, 80, “127.0.0.1”]

  • 4-elements array such as [“AF_INET”, 80, ignored, “127.0.0.1”]

flags should be bitwise OR of Socket::NI_* constants.

Note: The last form is compatible with IPSocket#addr and IPSocket#peeraddr.

Socket.getnameinfo(Socket.sockaddr_in(80, "127.0.0.1"))       #=> ["localhost", "www"]
Socket.getnameinfo(["AF_INET", 80, "127.0.0.1"])              #=> ["localhost", "www"]
Socket.getnameinfo(["AF_INET", 80, "localhost", "127.0.0.1"]) #=> ["localhost", "www"]

If Addrinfo object is preferred, use Addrinfo#getnameinfo.

static VALUE
sock_s_getnameinfo(int argc, VALUE *argv)
{
    VALUE sa, af = Qnil, host = Qnil, port = Qnil, flags, tmp;
    char *hptr, *pptr;
    char hbuf[1024], pbuf[1024];
    int fl;
    struct rb_addrinfo *res = NULL;
    struct addrinfo hints, *r;
    int error, saved_errno;
    union_sockaddr ss;
    struct sockaddr *sap;
    socklen_t salen;

    sa = flags = Qnil;
    rb_scan_args(argc, argv, "11", &sa, &flags);

    fl = 0;
    if (!NIL_P(flags)) {
        fl = NUM2INT(flags);
    }
    tmp = rb_check_sockaddr_string_type(sa);
    if (!NIL_P(tmp)) {
        sa = tmp;
        if (sizeof(ss) < (size_t)RSTRING_LEN(sa)) {
            rb_raise(rb_eTypeError, "sockaddr length too big");
        }
        memcpy(&ss, RSTRING_PTR(sa), RSTRING_LEN(sa));
        if (!VALIDATE_SOCKLEN(&ss.addr, RSTRING_LEN(sa))) {
            rb_raise(rb_eTypeError, "sockaddr size differs - should not happen");
        }
        sap = &ss.addr;
        salen = RSTRING_SOCKLEN(sa);
        goto call_nameinfo;
    }
    tmp = rb_check_array_type(sa);
    if (!NIL_P(tmp)) {
        sa = tmp;
        MEMZERO(&hints, struct addrinfo, 1);
        if (RARRAY_LEN(sa) == 3) {
            af = RARRAY_AREF(sa, 0);
            port = RARRAY_AREF(sa, 1);
            host = RARRAY_AREF(sa, 2);
        }
        else if (RARRAY_LEN(sa) >= 4) {
            af = RARRAY_AREF(sa, 0);
            port = RARRAY_AREF(sa, 1);
            host = RARRAY_AREF(sa, 3);
            if (NIL_P(host)) {
                host = RARRAY_AREF(sa, 2);
            }
            else {
                /*
                 * 4th element holds numeric form, don't resolve.
                 * see rsock_ipaddr().
                 */
#ifdef AI_NUMERICHOST /* AIX 4.3.3 doesn't have AI_NUMERICHOST. */
                hints.ai_flags |= AI_NUMERICHOST;
#endif
            }
        }
        else {
            rb_raise(rb_eArgError, "array size should be 3 or 4, %ld given",
                     RARRAY_LEN(sa));
        }
        /* host */
        if (NIL_P(host)) {
            hptr = NULL;
        }
        else {
            strncpy(hbuf, StringValuePtr(host), sizeof(hbuf));
            hbuf[sizeof(hbuf) - 1] = '\0';
            hptr = hbuf;
        }
        /* port */
        if (NIL_P(port)) {
            strcpy(pbuf, "0");
            pptr = NULL;
        }
        else if (FIXNUM_P(port)) {
            snprintf(pbuf, sizeof(pbuf), "%ld", NUM2LONG(port));
            pptr = pbuf;
        }
        else {
            strncpy(pbuf, StringValuePtr(port), sizeof(pbuf));
            pbuf[sizeof(pbuf) - 1] = '\0';
            pptr = pbuf;
        }
        hints.ai_socktype = (fl & NI_DGRAM) ? SOCK_DGRAM : SOCK_STREAM;
        /* af */
        hints.ai_family = NIL_P(af) ? PF_UNSPEC : rsock_family_arg(af);
        error = rb_getaddrinfo(hptr, pptr, &hints, &res);
        if (error) goto error_exit_addr;
        sap = res->ai->ai_addr;
        salen = res->ai->ai_addrlen;
    }
    else {
        rb_raise(rb_eTypeError, "expecting String or Array");
    }

  call_nameinfo:
    error = rb_getnameinfo(sap, salen, hbuf, sizeof(hbuf),
                           pbuf, sizeof(pbuf), fl);
    if (error) goto error_exit_name;
    if (res) {
        for (r = res->ai->ai_next; r; r = r->ai_next) {
            char hbuf2[1024], pbuf2[1024];

            sap = r->ai_addr;
            salen = r->ai_addrlen;
            error = rb_getnameinfo(sap, salen, hbuf2, sizeof(hbuf2),
                                   pbuf2, sizeof(pbuf2), fl);
            if (error) goto error_exit_name;
            if (strcmp(hbuf, hbuf2) != 0|| strcmp(pbuf, pbuf2) != 0) {
                rb_freeaddrinfo(res);
                rb_raise(rb_eSocket, "sockaddr resolved to multiple nodename");
            }
        }
        rb_freeaddrinfo(res);
    }
    return rb_assoc_new(rb_str_new2(hbuf), rb_str_new2(pbuf));

  error_exit_addr:
    saved_errno = errno;
    if (res) rb_freeaddrinfo(res);
    errno = saved_errno;
    rsock_raise_socket_error("getaddrinfo", error);

  error_exit_name:
    saved_errno = errno;
    if (res) rb_freeaddrinfo(res);
    errno = saved_errno;
    rsock_raise_socket_error("getnameinfo", error);

    UNREACHABLE;
}
getservbyname(service_name) → port_number Show source
getservbyname(service_name, protocol_name) → port_number

Obtains the port number for service_name.

If protocol_name is not given, “tcp” is assumed.

Socket.getservbyname("smtp")          #=> 25
Socket.getservbyname("shell")         #=> 514
Socket.getservbyname("syslog", "udp") #=> 514
static VALUE
sock_s_getservbyname(int argc, VALUE *argv)
{
    VALUE service, proto;
    struct servent *sp;
    long port;
    const char *servicename, *protoname = "tcp";

    rb_scan_args(argc, argv, "11", &service, &proto);
    StringValue(service);
    if (!NIL_P(proto)) StringValue(proto);
    servicename = StringValueCStr(service);
    if (!NIL_P(proto)) protoname = StringValueCStr(proto);
    sp = getservbyname(servicename, protoname);
    if (sp) {
        port = ntohs(sp->s_port);
    }
    else {
        char *end;

        port = STRTOUL(servicename, &end, 0);
        if (*end != '\0') {
            rb_raise(rb_eSocket, "no such service %s/%s", servicename, protoname);
        }
    }
    return INT2FIX(port);
}
getservbyport(port [, protocol_name]) → service Show source

Obtains the port number for port.

If protocol_name is not given, “tcp” is assumed.

Socket.getservbyport(80)         #=> "www"
Socket.getservbyport(514, "tcp") #=> "shell"
Socket.getservbyport(514, "udp") #=> "syslog"
static VALUE
sock_s_getservbyport(int argc, VALUE *argv)
{
    VALUE port, proto;
    struct servent *sp;
    long portnum;
    const char *protoname = "tcp";

    rb_scan_args(argc, argv, "11", &port, &proto);
    portnum = NUM2LONG(port);
    if (portnum != (uint16_t)portnum) {
        const char *s = portnum > 0 ? "big" : "small";
        rb_raise(rb_eRangeError, "integer %ld too %s to convert into `int16_t'", portnum, s);
    }
    if (!NIL_P(proto)) protoname = StringValueCStr(proto);

    sp = getservbyport((int)htons((uint16_t)portnum), protoname);
    if (!sp) {
        rb_raise(rb_eSocket, "no such service for port %d/%s", (int)portnum, protoname);
    }
    return rb_tainted_str_new2(sp->s_name);
}
ip_address_list → array Show source

Returns local IP addresses as an array.

The array contains Addrinfo objects.

pp Socket.ip_address_list
#=> [#<Addrinfo: 127.0.0.1>,
     #<Addrinfo: 192.168.0.128>,
     #<Addrinfo: ::1>,
     ...]
static VALUE
socket_s_ip_address_list(VALUE self)
{
#if defined(HAVE_GETIFADDRS)
    struct ifaddrs *ifp = NULL;
    struct ifaddrs *p;
    int ret;
    VALUE list;

    ret = getifaddrs(&ifp);
    if (ret == -1) {
        rb_sys_fail("getifaddrs");
    }

    list = rb_ary_new();
    for (p = ifp; p; p = p->ifa_next) {
        if (p->ifa_addr != NULL && IS_IP_FAMILY(p->ifa_addr->sa_family)) {
            struct sockaddr *addr = p->ifa_addr;
#if defined(AF_INET6) && defined(__sun)
            /*
             * OpenIndiana SunOS 5.11 getifaddrs() returns IPv6 link local
             * address with sin6_scope_id == 0.
             * So fill it from the interface name (ifa_name).
             */
            struct sockaddr_in6 addr6;
            if (addr->sa_family == AF_INET6) {
                socklen_t len = (socklen_t)sizeof(struct sockaddr_in6);
                memcpy(&addr6, addr, len);
                addr = (struct sockaddr *)&addr6;
                if (IN6_IS_ADDR_LINKLOCAL(&addr6.sin6_addr) &&
                    addr6.sin6_scope_id == 0) {
                    unsigned int ifindex = if_nametoindex(p->ifa_name);
                    if (ifindex != 0) {
                        addr6.sin6_scope_id = ifindex;
                    }
                }
            }
#endif
            rb_ary_push(list, sockaddr_obj(addr, sockaddr_len(addr)));
        }
    }

    freeifaddrs(ifp);

    return list;
#elif defined(SIOCGLIFCONF) && defined(SIOCGLIFNUM) && !defined(__hpux)
    /* Solaris if_tcp(7P) */
    /* HP-UX has SIOCGLIFCONF too.  But it uses different struct */
    int fd = -1;
    int ret;
    struct lifnum ln;
    struct lifconf lc;
    const char *reason = NULL;
    int save_errno;
    int i;
    VALUE list = Qnil;

    lc.lifc_buf = NULL;

    fd = socket(AF_INET, SOCK_DGRAM, 0);
    if (fd == -1)
        rb_sys_fail("socket(2)");

    memset(&ln, 0, sizeof(ln));
    ln.lifn_family = AF_UNSPEC;

    ret = ioctl(fd, SIOCGLIFNUM, &ln);
    if (ret == -1) {
        reason = "SIOCGLIFNUM";
        goto finish;
    }

    memset(&lc, 0, sizeof(lc));
    lc.lifc_family = AF_UNSPEC;
    lc.lifc_flags = 0;
    lc.lifc_len = sizeof(struct lifreq) * ln.lifn_count;
    lc.lifc_req = xmalloc(lc.lifc_len);

    ret = ioctl(fd, SIOCGLIFCONF, &lc);
    if (ret == -1) {
        reason = "SIOCGLIFCONF";
        goto finish;
    }

    list = rb_ary_new();
    for (i = 0; i < ln.lifn_count; i++) {
        struct lifreq *req = &lc.lifc_req[i];
        if (IS_IP_FAMILY(req->lifr_addr.ss_family)) {
            if (req->lifr_addr.ss_family == AF_INET6 &&
                IN6_IS_ADDR_LINKLOCAL(&((struct sockaddr_in6 *)(&req->lifr_addr))->sin6_addr) &&
                ((struct sockaddr_in6 *)(&req->lifr_addr))->sin6_scope_id == 0) {
                struct lifreq req2;
                memcpy(req2.lifr_name, req->lifr_name, LIFNAMSIZ);
                ret = ioctl(fd, SIOCGLIFINDEX, &req2);
                if (ret == -1) {
                    reason = "SIOCGLIFINDEX";
                    goto finish;
                }
                ((struct sockaddr_in6 *)(&req->lifr_addr))->sin6_scope_id = req2.lifr_index;
            }
            rb_ary_push(list, sockaddr_obj((struct sockaddr *)&req->lifr_addr, req->lifr_addrlen));
        }
    }

  finish:
    save_errno = errno;
    if (lc.lifc_buf != NULL)
        xfree(lc.lifc_req);
    if (fd != -1)
        close(fd);
    errno = save_errno;

    if (reason)
        rb_syserr_fail(save_errno, reason);
    return list;

#elif defined(SIOCGIFCONF)
    int fd = -1;
    int ret;
#define EXTRA_SPACE ((int)(sizeof(struct ifconf) + sizeof(union_sockaddr)))
    char initbuf[4096+EXTRA_SPACE];
    char *buf = initbuf;
    int bufsize;
    struct ifconf conf;
    struct ifreq *req;
    VALUE list = Qnil;
    const char *reason = NULL;
    int save_errno;

    fd = socket(AF_INET, SOCK_DGRAM, 0);
    if (fd == -1)
        rb_sys_fail("socket(2)");

    bufsize = sizeof(initbuf);
    buf = initbuf;

  retry:
    conf.ifc_len = bufsize;
    conf.ifc_req = (struct ifreq *)buf;

    /* fprintf(stderr, "bufsize: %d\n", bufsize); */

    ret = ioctl(fd, SIOCGIFCONF, &conf);
    if (ret == -1) {
        reason = "SIOCGIFCONF";
        goto finish;
    }

    /* fprintf(stderr, "conf.ifc_len: %d\n", conf.ifc_len); */

    if (bufsize - EXTRA_SPACE < conf.ifc_len) {
        if (bufsize < conf.ifc_len) {
            /* NetBSD returns required size for all interfaces. */
            bufsize = conf.ifc_len + EXTRA_SPACE;
        }
        else {
            bufsize = bufsize << 1;
        }
        if (buf == initbuf)
            buf = NULL;
        buf = xrealloc(buf, bufsize);
        goto retry;
    }

    close(fd);
    fd = -1;

    list = rb_ary_new();
    req = conf.ifc_req;
    while ((char*)req < (char*)conf.ifc_req + conf.ifc_len) {
        struct sockaddr *addr = &req->ifr_addr;
        if (IS_IP_FAMILY(addr->sa_family)) {
            rb_ary_push(list, sockaddr_obj(addr, sockaddr_len(addr)));
        }
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
# ifndef _SIZEOF_ADDR_IFREQ
#  define _SIZEOF_ADDR_IFREQ(r) \
          (sizeof(struct ifreq) + \
           (sizeof(struct sockaddr) < (r).ifr_addr.sa_len ? \
            (r).ifr_addr.sa_len - sizeof(struct sockaddr) : \
            0))
# endif
        req = (struct ifreq *)((char*)req + _SIZEOF_ADDR_IFREQ(*req));
#else
        req = (struct ifreq *)((char*)req + sizeof(struct ifreq));
#endif
    }

  finish:

    save_errno = errno;
    if (buf != initbuf)
        xfree(buf);
    if (fd != -1)
        close(fd);
    errno = save_errno;

    if (reason)
        rb_syserr_fail(save_errno, reason);
    return list;

#undef EXTRA_SPACE
#elif defined(_WIN32)
    typedef struct ip_adapter_unicast_address_st {
        unsigned LONG_LONG dummy0;
        struct ip_adapter_unicast_address_st *Next;
        struct {
            struct sockaddr *lpSockaddr;
            int iSockaddrLength;
        } Address;
        int dummy1;
        int dummy2;
        int dummy3;
        long dummy4;
        long dummy5;
        long dummy6;
    } ip_adapter_unicast_address_t;
    typedef struct ip_adapter_anycast_address_st {
        unsigned LONG_LONG dummy0;
        struct ip_adapter_anycast_address_st *Next;
        struct {
            struct sockaddr *lpSockaddr;
            int iSockaddrLength;
        } Address;
    } ip_adapter_anycast_address_t;
    typedef struct ip_adapter_addresses_st {
        unsigned LONG_LONG dummy0;
        struct ip_adapter_addresses_st *Next;
        void *dummy1;
        ip_adapter_unicast_address_t *FirstUnicastAddress;
        ip_adapter_anycast_address_t *FirstAnycastAddress;
        void *dummy2;
        void *dummy3;
        void *dummy4;
        void *dummy5;
        void *dummy6;
        BYTE dummy7[8];
        DWORD dummy8;
        DWORD dummy9;
        DWORD dummy10;
        DWORD IfType;
        int OperStatus;
        DWORD dummy12;
        DWORD dummy13[16];
        void *dummy14;
    } ip_adapter_addresses_t;
    typedef ULONG (WINAPI *GetAdaptersAddresses_t)(ULONG, ULONG, PVOID, ip_adapter_addresses_t *, PULONG);
    HMODULE h;
    GetAdaptersAddresses_t pGetAdaptersAddresses;
    ULONG len;
    DWORD ret;
    ip_adapter_addresses_t *adapters;
    VALUE list;

    h = LoadLibrary("iphlpapi.dll");
    if (!h)
        rb_notimplement();
    pGetAdaptersAddresses = (GetAdaptersAddresses_t)GetProcAddress(h, "GetAdaptersAddresses");
    if (!pGetAdaptersAddresses) {
        FreeLibrary(h);
        rb_notimplement();
    }

    ret = pGetAdaptersAddresses(AF_UNSPEC, 0, NULL, NULL, &len);
    if (ret != ERROR_SUCCESS && ret != ERROR_BUFFER_OVERFLOW) {
        errno = rb_w32_map_errno(ret);
        FreeLibrary(h);
        rb_sys_fail("GetAdaptersAddresses");
    }
    adapters = (ip_adapter_addresses_t *)ALLOCA_N(BYTE, len);
    ret = pGetAdaptersAddresses(AF_UNSPEC, 0, NULL, adapters, &len);
    if (ret != ERROR_SUCCESS) {
        errno = rb_w32_map_errno(ret);
        FreeLibrary(h);
        rb_sys_fail("GetAdaptersAddresses");
    }

    list = rb_ary_new();
    for (; adapters; adapters = adapters->Next) {
        ip_adapter_unicast_address_t *uni;
        ip_adapter_anycast_address_t *any;
        if (adapters->OperStatus != 1) /* 1 means IfOperStatusUp */
            continue;
        for (uni = adapters->FirstUnicastAddress; uni; uni = uni->Next) {
#ifndef INET6
            if (uni->Address.lpSockaddr->sa_family == AF_INET)
#else
            if (IS_IP_FAMILY(uni->Address.lpSockaddr->sa_family))
#endif
                rb_ary_push(list, sockaddr_obj(uni->Address.lpSockaddr, uni->Address.iSockaddrLength));
        }
        for (any = adapters->FirstAnycastAddress; any; any = any->Next) {
#ifndef INET6
            if (any->Address.lpSockaddr->sa_family == AF_INET)
#else
            if (IS_IP_FAMILY(any->Address.lpSockaddr->sa_family))
#endif
                rb_ary_push(list, sockaddr_obj(any->Address.lpSockaddr, any->Address.iSockaddrLength));
        }
    }

    FreeLibrary(h);
    return list;
#endif
}
new(domain, socktype [, protocol]) → socket Show source

Creates a new socket object.

domain should be a communications domain such as: :INET, :INET6, :UNIX, etc.

socktype should be a socket type such as: :STREAM, :DGRAM, :RAW, etc.

protocol is optional and should be a protocol defined in the domain. If protocol is not given, 0 is used internally.

Socket.new(:INET, :STREAM) # TCP socket
Socket.new(:INET, :DGRAM)  # UDP socket
Socket.new(:UNIX, :STREAM) # UNIX stream socket
Socket.new(:UNIX, :DGRAM)  # UNIX datagram socket
static VALUE
sock_initialize(int argc, VALUE *argv, VALUE sock)
{
    VALUE domain, type, protocol;
    int fd;
    int d, t;

    rb_scan_args(argc, argv, "21", &domain, &type, &protocol);
    if (NIL_P(protocol))
        protocol = INT2FIX(0);

    setup_domain_and_type(domain, &d, type, &t);
    fd = rsock_socket(d, t, NUM2INT(protocol));
    if (fd < 0) rb_sys_fail("socket(2)");

    return rsock_init_sock(sock, fd);
}
pack_sockaddr_in(port, host) → sockaddr Show source

Packs port and host as an AF_INET/AF_INET6 sockaddr string.

Socket.sockaddr_in(80, "127.0.0.1")
#=> "\x02\x00\x00P\x7F\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00"

Socket.sockaddr_in(80, "::1")
#=> "\n\x00\x00P\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00"
static VALUE
sock_s_pack_sockaddr_in(VALUE self, VALUE port, VALUE host)
{
    struct rb_addrinfo *res = rsock_addrinfo(host, port, AF_UNSPEC, 0, 0);
    VALUE addr = rb_str_new((char*)res->ai->ai_addr, res->ai->ai_addrlen);

    rb_freeaddrinfo(res);
    OBJ_INFECT(addr, port);
    OBJ_INFECT(addr, host);

    return addr;
}
pack_sockaddr_un(path) → sockaddr Show source

Packs path as an AF_UNIX sockaddr string.

Socket.sockaddr_un("/tmp/sock") #=> "\x01\x00/tmp/sock\x00\x00..."
static VALUE
sock_s_pack_sockaddr_un(VALUE self, VALUE path)
{
    struct sockaddr_un sockaddr;
    VALUE addr;

    StringValue(path);
    INIT_SOCKADDR_UN(&sockaddr, sizeof(struct sockaddr_un));
    if (sizeof(sockaddr.sun_path) < (size_t)RSTRING_LEN(path)) {
        rb_raise(rb_eArgError, "too long unix socket path (%"PRIuSIZE" bytes given but %"PRIuSIZE" bytes max)",
            (size_t)RSTRING_LEN(path), sizeof(sockaddr.sun_path));
    }
    memcpy(sockaddr.sun_path, RSTRING_PTR(path), RSTRING_LEN(path));
    addr = rb_str_new((char*)&sockaddr, rsock_unix_sockaddr_len(path));
    OBJ_INFECT(addr, path);

    return addr;
}
pair(domain, type, protocol) → [socket1, socket2] Show source

Creates a pair of sockets connected each other.

domain should be a communications domain such as: :INET, :INET6, :UNIX, etc.

socktype should be a socket type such as: :STREAM, :DGRAM, :RAW, etc.

protocol should be a protocol defined in the domain, defaults to 0 for the domain.

s1, s2 = Socket.pair(:UNIX, :STREAM, 0)
s1.send "a", 0
s1.send "b", 0
s1.close
p s2.recv(10) #=> "ab"
p s2.recv(10) #=> ""
p s2.recv(10) #=> ""

s1, s2 = Socket.pair(:UNIX, :DGRAM, 0)
s1.send "a", 0
s1.send "b", 0
p s2.recv(10) #=> "a"
p s2.recv(10) #=> "b"
VALUE
rsock_sock_s_socketpair(int argc, VALUE *argv, VALUE klass)
{
    VALUE domain, type, protocol;
    int d, t, p, sp[2];
    int ret;
    VALUE s1, s2, r;

    rb_scan_args(argc, argv, "21", &domain, &type, &protocol);
    if (NIL_P(protocol))
        protocol = INT2FIX(0);

    setup_domain_and_type(domain, &d, type, &t);
    p = NUM2INT(protocol);
    ret = rsock_socketpair(d, t, p, sp);
    if (ret < 0) {
        rb_sys_fail("socketpair(2)");
    }

    s1 = rsock_init_sock(rb_obj_alloc(klass), sp[0]);
    s2 = rsock_init_sock(rb_obj_alloc(klass), sp[1]);
    r = rb_assoc_new(s1, s2);
    if (rb_block_given_p()) {
        return rb_ensure(pair_yield, r, io_close, s1);
    }
    return r;
}
sockaddr_in(port, host) → sockaddr Show source

Packs port and host as an AF_INET/AF_INET6 sockaddr string.

Socket.sockaddr_in(80, "127.0.0.1")
#=> "\x02\x00\x00P\x7F\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00"

Socket.sockaddr_in(80, "::1")
#=> "\n\x00\x00P\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00"
static VALUE
sock_s_pack_sockaddr_in(VALUE self, VALUE port, VALUE host)
{
    struct rb_addrinfo *res = rsock_addrinfo(host, port, AF_UNSPEC, 0, 0);
    VALUE addr = rb_str_new((char*)res->ai->ai_addr, res->ai->ai_addrlen);

    rb_freeaddrinfo(res);
    OBJ_INFECT(addr, port);
    OBJ_INFECT(addr, host);

    return addr;
}
sockaddr_un(path) → sockaddr Show source

Packs path as an AF_UNIX sockaddr string.

Socket.sockaddr_un("/tmp/sock") #=> "\x01\x00/tmp/sock\x00\x00..."
static VALUE
sock_s_pack_sockaddr_un(VALUE self, VALUE path)
{
    struct sockaddr_un sockaddr;
    VALUE addr;

    StringValue(path);
    INIT_SOCKADDR_UN(&sockaddr, sizeof(struct sockaddr_un));
    if (sizeof(sockaddr.sun_path) < (size_t)RSTRING_LEN(path)) {
        rb_raise(rb_eArgError, "too long unix socket path (%"PRIuSIZE" bytes given but %"PRIuSIZE" bytes max)",
            (size_t)RSTRING_LEN(path), sizeof(sockaddr.sun_path));
    }
    memcpy(sockaddr.sun_path, RSTRING_PTR(path), RSTRING_LEN(path));
    addr = rb_str_new((char*)&sockaddr, rsock_unix_sockaddr_len(path));
    OBJ_INFECT(addr, path);

    return addr;
}
socketpair(domain, type, protocol) → [socket1, socket2] Show source

Creates a pair of sockets connected each other.

domain should be a communications domain such as: :INET, :INET6, :UNIX, etc.

socktype should be a socket type such as: :STREAM, :DGRAM, :RAW, etc.

protocol should be a protocol defined in the domain, defaults to 0 for the domain.

s1, s2 = Socket.pair(:UNIX, :STREAM, 0)
s1.send "a", 0
s1.send "b", 0
s1.close
p s2.recv(10) #=> "ab"
p s2.recv(10) #=> ""
p s2.recv(10) #=> ""

s1, s2 = Socket.pair(:UNIX, :DGRAM, 0)
s1.send "a", 0
s1.send "b", 0
p s2.recv(10) #=> "a"
p s2.recv(10) #=> "b"
VALUE
rsock_sock_s_socketpair(int argc, VALUE *argv, VALUE klass)
{
    VALUE domain, type, protocol;
    int d, t, p, sp[2];
    int ret;
    VALUE s1, s2, r;

    rb_scan_args(argc, argv, "21", &domain, &type, &protocol);
    if (NIL_P(protocol))
        protocol = INT2FIX(0);

    setup_domain_and_type(domain, &d, type, &t);
    p = NUM2INT(protocol);
    ret = rsock_socketpair(d, t, p, sp);
    if (ret < 0) {
        rb_sys_fail("socketpair(2)");
    }

    s1 = rsock_init_sock(rb_obj_alloc(klass), sp[0]);
    s2 = rsock_init_sock(rb_obj_alloc(klass), sp[1]);
    r = rb_assoc_new(s1, s2);
    if (rb_block_given_p()) {
        return rb_ensure(pair_yield, r, io_close, s1);
    }
    return r;
}
tcp(host, port, local_host=nil, local_port=nil, [opts]) {|socket| ... } Show source
tcp(host, port, local_host=nil, local_port=nil, [opts])

creates a new socket object connected to host:port using TCP/IP.

If local_host:local_port is given, the socket is bound to it.

The optional last argument opts is options represented by a hash. opts may have following options:

:connect_timeout

specify the timeout in seconds.

If a block is given, the block is called with the socket. The value of the block is returned. The socket is closed when this method returns.

If no block is given, the socket is returned.

Socket.tcp("www.ruby-lang.org", 80) {|sock|
  sock.print "GET / HTTP/1.0\r\nHost: www.ruby-lang.org\r\n\r\n"
  sock.close_write
  puts sock.read
}
# File ext/socket/lib/socket.rb, line 607
def self.tcp(host, port, local_host = nil, local_port = nil, connect_timeout: nil) # :yield: socket
  last_error = nil
  ret = nil

  local_addr_list = nil
  if local_host != nil || local_port != nil
    local_addr_list = Addrinfo.getaddrinfo(local_host, local_port, nil, :STREAM, nil)
  end

  Addrinfo.foreach(host, port, nil, :STREAM) {|ai|
    if local_addr_list
      local_addr = local_addr_list.find {|local_ai| local_ai.afamily == ai.afamily }
      next unless local_addr
    else
      local_addr = nil
    end
    begin
      sock = local_addr ?
        ai.connect_from(local_addr, timeout: connect_timeout) :
        ai.connect(timeout: connect_timeout)
    rescue SystemCallError
      last_error = $!
      next
    end
    ret = sock
    break
  }
  unless ret
    if last_error
      raise last_error
    else
      raise SocketError, "no appropriate local address"
    end
  end
  if block_given?
    begin
      yield ret
    ensure
      ret.close
    end
  else
    ret
  end
end
tcp_server_loop(host=nil, port) { |socket, client_addrinfo| ... } Show source

creates a TCP/IP server on port and calls the block for each connection accepted. The block is called with a socket and a client_address as an Addrinfo object.

If host is specified, it is used with port to determine the server addresses.

The socket is not closed when the block returns. So application should close it explicitly.

This method calls the block sequentially. It means that the next connection is not accepted until the block returns. So concurrent mechanism, thread for example, should be used to service multiple clients at a time.

Note that Addrinfo.getaddrinfo is used to determine the server socket addresses. When Addrinfo.getaddrinfo returns two or more addresses, IPv4 and IPv6 address for example, all of them are used. ::tcp_server_loop succeeds if one socket can be used at least.

# Sequential echo server.
# It services only one client at a time.
Socket.tcp_server_loop(16807) {|sock, client_addrinfo|
  begin
    IO.copy_stream(sock, sock)
  ensure
    sock.close
  end
}

# Threaded echo server
# It services multiple clients at a time.
# Note that it may accept connections too much.
Socket.tcp_server_loop(16807) {|sock, client_addrinfo|
  Thread.new {
    begin
      IO.copy_stream(sock, sock)
    ensure
      sock.close
    end
  }
}
# File ext/socket/lib/socket.rb, line 840
def self.tcp_server_loop(host=nil, port, &b) # :yield: socket, client_addrinfo
  tcp_server_sockets(host, port) {|sockets|
    accept_loop(sockets, &b)
  }
end
tcp_server_sockets(host=nil, port) { |sockets| ... } Show source

creates TCP/IP server sockets for host and port. host is optional.

If no block given, it returns an array of listening sockets.

If a block is given, the block is called with the sockets. The value of the block is returned. The socket is closed when this method returns.

If port is 0, actual port number is chosen dynamically. However all sockets in the result has same port number.

# tcp_server_sockets returns two sockets.
sockets = Socket.tcp_server_sockets(1296)
p sockets #=> [#<Socket:fd 3>, #<Socket:fd 4>]

# The sockets contains IPv6 and IPv4 sockets.
sockets.each {|s| p s.local_address }
#=> #<Addrinfo: [::]:1296 TCP>
#   #<Addrinfo: 0.0.0.0:1296 TCP>

# IPv6 and IPv4 socket has same port number, 53114, even if it is chosen dynamically.
sockets = Socket.tcp_server_sockets(0)
sockets.each {|s| p s.local_address }
#=> #<Addrinfo: [::]:53114 TCP>
#   #<Addrinfo: 0.0.0.0:53114 TCP>

# The block is called with the sockets.
Socket.tcp_server_sockets(0) {|sockets|
  p sockets #=> [#<Socket:fd 3>, #<Socket:fd 4>]
}
# File ext/socket/lib/socket.rb, line 740
def self.tcp_server_sockets(host=nil, port)
  if port == 0
    sockets = tcp_server_sockets_port0(host)
  else
    last_error = nil
    sockets = []
    begin
      Addrinfo.foreach(host, port, nil, :STREAM, nil, Socket::AI_PASSIVE) {|ai|
        begin
          s = ai.listen
        rescue SystemCallError
          last_error = $!
          next
        end
        sockets << s
      }
      if sockets.empty?
        raise last_error
      end
    rescue Exception
      sockets.each(&:close)
      raise
    end
  end
  if block_given?
    begin
      yield sockets
    ensure
      sockets.each(&:close)
    end
  else
    sockets
  end
end
udp_server_loop(port) {|msg, msg_src| ... } Show source
udp_server_loop(host, port) {|msg, msg_src| ... }

creates a UDP/IP server on port and calls the block for each message arrived. The block is called with the message and its source information.

This method allocates sockets internally using port. If host is specified, it is used conjunction with port to determine the server addresses.

The msg is a string.

The msg_src is a Socket::UDPSource object. It is used for reply.

# UDP/IP echo server.
Socket.udp_server_loop(9261) {|msg, msg_src|
  msg_src.reply msg
}
# File ext/socket/lib/socket.rb, line 1009
def self.udp_server_loop(host=nil, port, &b) # :yield: message, message_source
  udp_server_sockets(host, port) {|sockets|
    udp_server_loop_on(sockets, &b)
  }
end
udp_server_loop_on(sockets) {|msg, msg_src| ... } Show source

Run UDP/IP server loop on the given sockets.

The return value of ::udp_server_sockets is appropriate for the argument.

It calls the block for each message received.

# File ext/socket/lib/socket.rb, line 982
def self.udp_server_loop_on(sockets, &b) # :yield: msg, msg_src
  loop {
    readable, _, _ = IO.select(sockets)
    udp_server_recv(readable, &b)
  }
end
udp_server_recv(sockets) {|msg, msg_src| ... } Show source

Receive UDP/IP packets from the given sockets. For each packet received, the block is called.

The block receives msg and msg_src. msg is a string which is the payload of the received packet. msg_src is a Socket::UDPSource object which is used for reply.

::udp_server_loop can be implemented using this method as follows.

udp_server_sockets(host, port) {|sockets|
  loop {
    readable, _, _ = IO.select(sockets)
    udp_server_recv(readable) {|msg, msg_src| ... }
  }
}
# File ext/socket/lib/socket.rb, line 955
def self.udp_server_recv(sockets)
  sockets.each {|r|
    msg, sender_addrinfo, _, *controls = r.recvmsg_nonblock(exception: false)
    next if msg == :wait_readable
    ai = r.local_address
    if ai.ipv6? and pktinfo = controls.find {|c| c.cmsg_is?(:IPV6, :PKTINFO) }
      ai = Addrinfo.udp(pktinfo.ipv6_pktinfo_addr.ip_address, ai.ip_port)
      yield msg, UDPSource.new(sender_addrinfo, ai) {|reply_msg|
        r.sendmsg reply_msg, 0, sender_addrinfo, pktinfo
      }
    else
      yield msg, UDPSource.new(sender_addrinfo, ai) {|reply_msg|
        r.send reply_msg, 0, sender_addrinfo
      }
    end
  }
end
udp_server_sockets([host, ] port) Show source

Creates UDP/IP sockets for a UDP server.

If no block given, it returns an array of sockets.

If a block is given, the block is called with the sockets. The value of the block is returned. The sockets are closed when this method returns.

If port is zero, some port is chosen. But the chosen port is used for the all sockets.

# UDP/IP echo server
Socket.udp_server_sockets(0) {|sockets|
  p sockets.first.local_address.ip_port     #=> 32963
  Socket.udp_server_loop_on(sockets) {|msg, msg_src|
    msg_src.reply msg
  }
}
# File ext/socket/lib/socket.rb, line 868
def self.udp_server_sockets(host=nil, port)
  last_error = nil
  sockets = []

  ipv6_recvpktinfo = nil
  if defined? Socket::AncillaryData
    if defined? Socket::IPV6_RECVPKTINFO # RFC 3542
      ipv6_recvpktinfo = Socket::IPV6_RECVPKTINFO
    elsif defined? Socket::IPV6_PKTINFO # RFC 2292
      ipv6_recvpktinfo = Socket::IPV6_PKTINFO
    end
  end

  local_addrs = Socket.ip_address_list

  ip_list = []
  Addrinfo.foreach(host, port, nil, :DGRAM, nil, Socket::AI_PASSIVE) {|ai|
    if ai.ipv4? && ai.ip_address == "0.0.0.0"
      local_addrs.each {|a|
        next unless a.ipv4?
        ip_list << Addrinfo.new(a.to_sockaddr, :INET, :DGRAM, 0);
      }
    elsif ai.ipv6? && ai.ip_address == "::" && !ipv6_recvpktinfo
      local_addrs.each {|a|
        next unless a.ipv6?
        ip_list << Addrinfo.new(a.to_sockaddr, :INET6, :DGRAM, 0);
      }
    else
      ip_list << ai
    end
  }

  if port == 0
    sockets = ip_sockets_port0(ip_list, false)
  else
    ip_list.each {|ip|
      ai = Addrinfo.udp(ip.ip_address, port)
      begin
        s = ai.bind
      rescue SystemCallError
        last_error = $!
        next
      end
      sockets << s
    }
    if sockets.empty?
      raise last_error
    end
  end

  sockets.each {|s|
    ai = s.local_address
    if ipv6_recvpktinfo && ai.ipv6? && ai.ip_address == "::"
      s.setsockopt(:IPV6, ipv6_recvpktinfo, 1)
    end
  }

  if block_given?
    begin
      yield sockets
    ensure
      sockets.each(&:close) if sockets
    end
  else
    sockets
  end
end
unix(path) { |socket| ... } Show source

creates a new socket connected to path using UNIX socket socket.

If a block is given, the block is called with the socket. The value of the block is returned. The socket is closed when this method returns.

If no block is given, the socket is returned.

# talk to /tmp/sock socket.
Socket.unix("/tmp/sock") {|sock|
  t = Thread.new { IO.copy_stream(sock, STDOUT) }
  IO.copy_stream(STDIN, sock)
  t.join
}
# File ext/socket/lib/socket.rb, line 1059
def self.unix(path) # :yield: socket
  addr = Addrinfo.unix(path)
  sock = addr.connect
  if block_given?
    begin
      yield sock
    ensure
      sock.close
    end
  else
    sock
  end
end
unix_server_loop(path) { |socket, client_addrinfo| ... } Show source

creates a UNIX socket server on path. It calls the block for each socket accepted.

If host is specified, it is used with port to determine the server ports.

The socket is not closed when the block returns. So application should close it.

This method deletes the socket file pointed by path at first if the file is a socket file and it is owned by the user of the application. This is safe only if the directory of path is not changed by a malicious user. So don't use /tmp/malicious-users-directory/socket. Note that /tmp/socket and /tmp/your-private-directory/socket is safe assuming that /tmp has sticky bit.

# Sequential echo server.
# It services only one client at a time.
Socket.unix_server_loop("/tmp/sock") {|sock, client_addrinfo|
  begin
    IO.copy_stream(sock, sock)
  ensure
    sock.close
  end
}
# File ext/socket/lib/socket.rb, line 1146
def self.unix_server_loop(path, &b) # :yield: socket, client_addrinfo
  unix_server_socket(path) {|serv|
    accept_loop(serv, &b)
  }
end
unix_server_socket(path) { |s| ... } Show source

creates a UNIX server socket on path

If no block given, it returns a listening socket.

If a block is given, it is called with the socket and the block value is returned. When the block exits, the socket is closed and the socket file is removed.

socket = Socket.unix_server_socket("/tmp/s")
p socket                  #=> #<Socket:fd 3>
p socket.local_address    #=> #<Addrinfo: /tmp/s SOCK_STREAM>

Socket.unix_server_socket("/tmp/sock") {|s|
  p s                     #=> #<Socket:fd 3>
  p s.local_address       #=> # #<Addrinfo: /tmp/sock SOCK_STREAM>
}
# File ext/socket/lib/socket.rb, line 1089
def self.unix_server_socket(path)
  unless unix_socket_abstract_name?(path)
    begin
      st = File.lstat(path)
    rescue Errno::ENOENT
    end
    if st&.socket? && st.owned?
      File.unlink path
    end
  end
  s = Addrinfo.unix(path).listen
  if block_given?
    begin
      yield s
    ensure
      s.close
      unless unix_socket_abstract_name?(path)
        File.unlink path
      end
    end
  else
    s
  end
end
unpack_sockaddr_in(sockaddr) → [port, ip_address] Show source

Unpacks sockaddr into port and ip_address.

sockaddr should be a string or an addrinfo for AF_INET/AF_INET6.

sockaddr = Socket.sockaddr_in(80, "127.0.0.1")
p sockaddr #=> "\x02\x00\x00P\x7F\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00"
p Socket.unpack_sockaddr_in(sockaddr) #=> [80, "127.0.0.1"]
static VALUE
sock_s_unpack_sockaddr_in(VALUE self, VALUE addr)
{
    struct sockaddr_in * sockaddr;
    VALUE host;

    sockaddr = (struct sockaddr_in*)SockAddrStringValuePtr(addr);
    if (RSTRING_LEN(addr) <
        (char*)&((struct sockaddr *)sockaddr)->sa_family +
        sizeof(((struct sockaddr *)sockaddr)->sa_family) -
        (char*)sockaddr)
        rb_raise(rb_eArgError, "too short sockaddr");
    if (((struct sockaddr *)sockaddr)->sa_family != AF_INET
#ifdef INET6
        && ((struct sockaddr *)sockaddr)->sa_family != AF_INET6
#endif
        ) {
#ifdef INET6
        rb_raise(rb_eArgError, "not an AF_INET/AF_INET6 sockaddr");
#else
        rb_raise(rb_eArgError, "not an AF_INET sockaddr");
#endif
    }
    host = rsock_make_ipaddr((struct sockaddr*)sockaddr, RSTRING_SOCKLEN(addr));
    OBJ_INFECT(host, addr);
    return rb_assoc_new(INT2NUM(ntohs(sockaddr->sin_port)), host);
}
unpack_sockaddr_un(sockaddr) → path Show source

Unpacks sockaddr into path.

sockaddr should be a string or an addrinfo for AF_UNIX.

sockaddr = Socket.sockaddr_un("/tmp/sock")
p Socket.unpack_sockaddr_un(sockaddr) #=> "/tmp/sock"
static VALUE
sock_s_unpack_sockaddr_un(VALUE self, VALUE addr)
{
    struct sockaddr_un * sockaddr;
    VALUE path;

    sockaddr = (struct sockaddr_un*)SockAddrStringValuePtr(addr);
    if (RSTRING_LEN(addr) <
        (char*)&((struct sockaddr *)sockaddr)->sa_family +
        sizeof(((struct sockaddr *)sockaddr)->sa_family) -
        (char*)sockaddr)
        rb_raise(rb_eArgError, "too short sockaddr");
    if (((struct sockaddr *)sockaddr)->sa_family != AF_UNIX) {
        rb_raise(rb_eArgError, "not an AF_UNIX sockaddr");
    }
    if (sizeof(struct sockaddr_un) < (size_t)RSTRING_LEN(addr)) {
        rb_raise(rb_eTypeError, "too long sockaddr_un - %ld longer than %d",
                 RSTRING_LEN(addr), (int)sizeof(struct sockaddr_un));
    }
    path = rsock_unixpath_str(sockaddr, RSTRING_SOCKLEN(addr));
    OBJ_INFECT(path, addr);
    return path;
}

Private Class Methods

unix_socket_abstract_name?(path) Show source
# File ext/socket/lib/socket.rb, line 1117
def unix_socket_abstract_name?(path)
  /linux/ =~ RUBY_PLATFORM && /\A(\0|\z)/ =~ path
end

Public Instance Methods

accept → [client_socket, client_addrinfo] Show source

Accepts a next connection. Returns a new Socket object and Addrinfo object.

serv = Socket.new(:INET, :STREAM, 0)
serv.listen(5)
c = Socket.new(:INET, :STREAM, 0)
c.connect(serv.connect_address)
p serv.accept #=> [#<Socket:fd 6>, #<Addrinfo: 127.0.0.1:48555 TCP>]
static VALUE
sock_accept(VALUE sock)
{
    rb_io_t *fptr;
    VALUE sock2;
    union_sockaddr buf;
    socklen_t len = (socklen_t)sizeof buf;

    GetOpenFile(sock, fptr);
    sock2 = rsock_s_accept(rb_cSocket,fptr->fd,&buf.addr,&len);

    return rb_assoc_new(sock2, rsock_io_socket_addrinfo(sock2, &buf.addr, len));
}
accept_nonblock([options]) → [client_socket, client_addrinfo] Show source

Accepts an incoming connection using accept(2) after O_NONBLOCK is set for the underlying file descriptor. It returns an array containing the accepted socket for the incoming connection, client_socket, and an Addrinfo, client_addrinfo.

Example

# In one script, start this first
require 'socket'
include Socket::Constants
socket = Socket.new(AF_INET, SOCK_STREAM, 0)
sockaddr = Socket.sockaddr_in(2200, 'localhost')
socket.bind(sockaddr)
socket.listen(5)
begin # emulate blocking accept
  client_socket, client_addrinfo = socket.accept_nonblock
rescue IO::WaitReadable, Errno::EINTR
  IO.select([socket])
  retry
end
puts "The client said, '#{client_socket.readline.chomp}'"
client_socket.puts "Hello from script one!"
socket.close

# In another script, start this second
require 'socket'
include Socket::Constants
socket = Socket.new(AF_INET, SOCK_STREAM, 0)
sockaddr = Socket.sockaddr_in(2200, 'localhost')
socket.connect(sockaddr)
socket.puts "Hello from script 2."
puts "The server said, '#{socket.readline.chomp}'"
socket.close

Refer to #accept for the exceptions that may be thrown if the call to accept_nonblock fails.

#accept_nonblock may raise any error corresponding to accept(2) failure, including Errno::EWOULDBLOCK.

If the exception is Errno::EWOULDBLOCK, Errno::EAGAIN, Errno::ECONNABORTED or Errno::EPROTO, it is extended by IO::WaitReadable. So IO::WaitReadable can be used to rescue the exceptions for retrying accept_nonblock.

By specifying a keyword argument exception to false, you can indicate that #accept_nonblock should not raise an IO::WaitReadable exception, but return the symbol :wait_readable instead.

See

# File ext/socket/lib/socket.rb, line 577
def accept_nonblock(exception: true)
  __accept_nonblock(exception)
end
bind(local_sockaddr) → 0 Show source

Binds to the given local address.

Parameter

  • local_sockaddr - the struct sockaddr contained in a string or an Addrinfo object

Example

require 'socket'

# use Addrinfo
socket = Socket.new(:INET, :STREAM, 0)
socket.bind(Addrinfo.tcp("127.0.0.1", 2222))
p socket.local_address #=> #<Addrinfo: 127.0.0.1:2222 TCP>

# use struct sockaddr
include Socket::Constants
socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' )
socket.bind( sockaddr )

Unix-based Exceptions

On unix-based based systems the following system exceptions may be raised if the call to bind fails:

  • Errno::EACCES - the specified sockaddr is protected and the current user does not have permission to bind to it

  • Errno::EADDRINUSE - the specified sockaddr is already in use

  • Errno::EADDRNOTAVAIL - the specified sockaddr is not available from the local machine

  • Errno::EAFNOSUPPORT - the specified sockaddr is not a valid address for the family of the calling socket

  • Errno::EBADF - the sockaddr specified is not a valid file descriptor

  • Errno::EFAULT - the sockaddr argument cannot be accessed

  • Errno::EINVAL - the socket is already bound to an address, and the protocol does not support binding to the new sockaddr or the socket has been shut down.

  • Errno::EINVAL - the address length is not a valid length for the address family

  • Errno::ENAMETOOLONG - the pathname resolved had a length which exceeded PATH_MAX

  • Errno::ENOBUFS - no buffer space is available

  • Errno::ENOSR - there were insufficient STREAMS resources available to complete the operation

  • Errno::ENOTSOCK - the socket does not refer to a socket

  • Errno::EOPNOTSUPP - the socket type of the socket does not support binding to an address

On unix-based based systems if the address family of the calling socket is Socket::AF_UNIX the follow exceptions may be raised if the call to bind fails:

  • Errno::EACCES - search permission is denied for a component of the prefix path or write access to the socket is denied

  • Errno::EDESTADDRREQ - the sockaddr argument is a null pointer

  • Errno::EISDIR - same as Errno::EDESTADDRREQ

  • Errno::EIO - an i/o error occurred

  • Errno::ELOOP - too many symbolic links were encountered in translating the pathname in sockaddr

  • Errno::ENAMETOOLLONG - a component of a pathname exceeded NAME_MAX characters, or an entire pathname exceeded PATH_MAX characters

  • Errno::ENOENT - a component of the pathname does not name an existing file or the pathname is an empty string

  • Errno::ENOTDIR - a component of the path prefix of the pathname in sockaddr is not a directory

  • Errno::EROFS - the name would reside on a read only filesystem

Windows Exceptions

On Windows systems the following system exceptions may be raised if the call to bind fails:

  • Errno::ENETDOWN– the network is down

  • Errno::EACCES - the attempt to connect the datagram socket to the broadcast address failed

  • Errno::EADDRINUSE - the socket's local address is already in use

  • Errno::EADDRNOTAVAIL - the specified address is not a valid address for this computer

  • Errno::EFAULT - the socket's internal address or address length parameter is too small or is not a valid part of the user space addressed

  • Errno::EINVAL - the socket is already bound to an address

  • Errno::ENOBUFS - no buffer space is available

  • Errno::ENOTSOCK - the socket argument does not refer to a socket

See

  • bind manual pages on unix-based systems

  • bind function in Microsoft's Winsock functions reference

static VALUE
sock_bind(VALUE sock, VALUE addr)
{
    VALUE rai;
    rb_io_t *fptr;

    SockAddrStringValueWithAddrinfo(addr, rai);
    GetOpenFile(sock, fptr);
    if (bind(fptr->fd, (struct sockaddr*)RSTRING_PTR(addr), RSTRING_SOCKLEN(addr)) < 0)
        rsock_sys_fail_raddrinfo_or_sockaddr("bind(2)", addr, rai);

    return INT2FIX(0);
}
connect(remote_sockaddr) → 0 Show source

Requests a connection to be made on the given remote_sockaddr. Returns 0 if successful, otherwise an exception is raised.

Parameter

  • remote_sockaddr - the struct sockaddr contained in a string or Addrinfo object

Example:

# Pull down Google's web page
require 'socket'
include Socket::Constants
socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
sockaddr = Socket.pack_sockaddr_in( 80, 'www.google.com' )
socket.connect( sockaddr )
socket.write( "GET / HTTP/1.0\r\n\r\n" )
results = socket.read

Unix-based Exceptions

On unix-based systems the following system exceptions may be raised if the call to connect fails:

  • Errno::EACCES - search permission is denied for a component of the prefix path or write access to the socket is denied

  • Errno::EADDRINUSE - the sockaddr is already in use

  • Errno::EADDRNOTAVAIL - the specified sockaddr is not available from the local machine

  • Errno::EAFNOSUPPORT - the specified sockaddr is not a valid address for the address family of the specified socket

  • Errno::EALREADY - a connection is already in progress for the specified socket

  • Errno::EBADF - the socket is not a valid file descriptor

  • Errno::ECONNREFUSED - the target sockaddr was not listening for connections refused the connection request

  • Errno::ECONNRESET - the remote host reset the connection request

  • Errno::EFAULT - the sockaddr cannot be accessed

  • Errno::EHOSTUNREACH - the destination host cannot be reached (probably because the host is down or a remote router cannot reach it)

  • Errno::EINPROGRESS - the O_NONBLOCK is set for the socket and the connection cannot be immediately established; the connection will be established asynchronously

  • Errno::EINTR - the attempt to establish the connection was interrupted by delivery of a signal that was caught; the connection will be established asynchronously

  • Errno::EISCONN - the specified socket is already connected

  • Errno::EINVAL - the address length used for the sockaddr is not a valid length for the address family or there is an invalid family in sockaddr

  • Errno::ENAMETOOLONG - the pathname resolved had a length which exceeded PATH_MAX

  • Errno::ENETDOWN - the local interface used to reach the destination is down

  • Errno::ENETUNREACH - no route to the network is present

  • Errno::ENOBUFS - no buffer space is available

  • Errno::ENOSR - there were insufficient STREAMS resources available to complete the operation

  • Errno::ENOTSOCK - the socket argument does not refer to a socket

  • Errno::EOPNOTSUPP - the calling socket is listening and cannot be connected

  • Errno::EPROTOTYPE - the sockaddr has a different type than the socket bound to the specified peer address

  • Errno::ETIMEDOUT - the attempt to connect time out before a connection was made.

On unix-based systems if the address family of the calling socket is AF_UNIX the follow exceptions may be raised if the call to connect fails:

  • Errno::EIO - an i/o error occurred while reading from or writing to the file system

  • Errno::ELOOP - too many symbolic links were encountered in translating the pathname in sockaddr

  • Errno::ENAMETOOLLONG - a component of a pathname exceeded NAME_MAX characters, or an entire pathname exceeded PATH_MAX characters

  • Errno::ENOENT - a component of the pathname does not name an existing file or the pathname is an empty string

  • Errno::ENOTDIR - a component of the path prefix of the pathname in sockaddr is not a directory

Windows Exceptions

On Windows systems the following system exceptions may be raised if the call to connect fails:

  • Errno::ENETDOWN - the network is down

  • Errno::EADDRINUSE - the socket's local address is already in use

  • Errno::EINTR - the socket was cancelled

  • Errno::EINPROGRESS - a blocking socket is in progress or the service provider is still processing a callback function. Or a nonblocking connect call is in progress on the socket.

  • Errno::EALREADY - see Errno::EINVAL

  • Errno::EADDRNOTAVAIL - the remote address is not a valid address, such as ADDR_ANY TODO check ADDRANY TO INADDR_ANY

  • Errno::EAFNOSUPPORT - addresses in the specified family cannot be used with with this socket

  • Errno::ECONNREFUSED - the target sockaddr was not listening for connections refused the connection request

  • Errno::EFAULT - the socket's internal address or address length parameter is too small or is not a valid part of the user space address

  • Errno::EINVAL - the socket is a listening socket

  • Errno::EISCONN - the socket is already connected

  • Errno::ENETUNREACH - the network cannot be reached from this host at this time

  • Errno::EHOSTUNREACH - no route to the network is present

  • Errno::ENOBUFS - no buffer space is available

  • Errno::ENOTSOCK - the socket argument does not refer to a socket

  • Errno::ETIMEDOUT - the attempt to connect time out before a connection was made.

  • Errno::EWOULDBLOCK - the socket is marked as nonblocking and the connection cannot be completed immediately

  • Errno::EACCES - the attempt to connect the datagram socket to the broadcast address failed

See

  • connect manual pages on unix-based systems

  • connect function in Microsoft's Winsock functions reference

static VALUE
sock_connect(VALUE sock, VALUE addr)
{
    VALUE rai;
    rb_io_t *fptr;
    int fd, n;

    SockAddrStringValueWithAddrinfo(addr, rai);
    addr = rb_str_new4(addr);
    GetOpenFile(sock, fptr);
    fd = fptr->fd;
    n = rsock_connect(fd, (struct sockaddr*)RSTRING_PTR(addr), RSTRING_SOCKLEN(addr), 0);
    if (n < 0) {
        rsock_sys_fail_raddrinfo_or_sockaddr("connect(2)", addr, rai);
    }

    return INT2FIX(n);
}
connect_nonblock(remote_sockaddr, [options]) → 0 Show source

Requests a connection to be made on the given remote_sockaddr after O_NONBLOCK is set for the underlying file descriptor. Returns 0 if successful, otherwise an exception is raised.

Parameter

# +remote_sockaddr+ - the +struct+ sockaddr contained in a string or Addrinfo object

Example:

# Pull down Google's web page
require 'socket'
include Socket::Constants
socket = Socket.new(AF_INET, SOCK_STREAM, 0)
sockaddr = Socket.sockaddr_in(80, 'www.google.com')
begin # emulate blocking connect
  socket.connect_nonblock(sockaddr)
rescue IO::WaitWritable
  IO.select(nil, [socket]) # wait 3-way handshake completion
  begin
    socket.connect_nonblock(sockaddr) # check connection failure
  rescue Errno::EISCONN
  end
end
socket.write("GET / HTTP/1.0\r\n\r\n")
results = socket.read

Refer to #connect for the exceptions that may be thrown if the call to connect_nonblock fails.

#connect_nonblock may raise any error corresponding to connect(2) failure, including Errno::EINPROGRESS.

If the exception is Errno::EINPROGRESS, it is extended by IO::WaitWritable. So IO::WaitWritable can be used to rescue the exceptions for retrying connect_nonblock.

By specifying a keyword argument exception to false, you can indicate that #connect_nonblock should not raise an IO::WaitWritable exception, but return the symbol :wait_writable instead.

See

# Socket#connect
# File ext/socket/lib/socket.rb, line 1196
def connect_nonblock(addr, exception: true)
  __connect_nonblock(addr, exception)
end
ipv6only!() Show source

enable the socket option IPV6_V6ONLY if IPV6_V6ONLY is available.

# File ext/socket/lib/socket.rb, line 448
def ipv6only!
  if defined? Socket::IPV6_V6ONLY
    self.setsockopt(:IPV6, :V6ONLY, 1)
  end
end
listen( int ) → 0 Show source

Listens for connections, using the specified int as the backlog. A call to listen only applies if the socket is of type SOCK_STREAM or SOCK_SEQPACKET.

Parameter

  • backlog - the maximum length of the queue for pending connections.

Example 1

require 'socket'
include Socket::Constants
socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' )
socket.bind( sockaddr )
socket.listen( 5 )

Example 2 (listening on an arbitrary port, unix-based systems only):

require 'socket'
include Socket::Constants
socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
socket.listen( 1 )

Unix-based Exceptions

On unix based systems the above will work because a new sockaddr struct is created on the address ADDR_ANY, for an arbitrary port number as handed off by the kernel. It will not work on Windows, because Windows requires that the socket is bound by calling bind before it can listen.

If the backlog amount exceeds the implementation-dependent maximum queue length, the implementation's maximum queue length will be used.

On unix-based based systems the following system exceptions may be raised if the call to listen fails:

  • Errno::EBADF - the socket argument is not a valid file descriptor

  • Errno::EDESTADDRREQ - the socket is not bound to a local address, and the protocol does not support listening on an unbound socket

  • Errno::EINVAL - the socket is already connected

  • Errno::ENOTSOCK - the socket argument does not refer to a socket

  • Errno::EOPNOTSUPP - the socket protocol does not support listen

  • Errno::EACCES - the calling process does not have appropriate privileges

  • Errno::EINVAL - the socket has been shut down

  • Errno::ENOBUFS - insufficient resources are available in the system to complete the call

Windows Exceptions

On Windows systems the following system exceptions may be raised if the call to listen fails:

  • Errno::ENETDOWN - the network is down

  • Errno::EADDRINUSE - the socket's local address is already in use. This usually occurs during the execution of bind but could be delayed if the call to bind was to a partially wildcard address (involving ADDR_ANY) and if a specific address needs to be committed at the time of the call to listen

  • Errno::EINPROGRESS - a Windows Sockets 1.1 call is in progress or the service provider is still processing a callback function

  • Errno::EINVAL - the socket has not been bound with a call to bind.

  • Errno::EISCONN - the socket is already connected

  • Errno::EMFILE - no more socket descriptors are available

  • Errno::ENOBUFS - no buffer space is available

  • Errno::ENOTSOC - socket is not a socket

  • Errno::EOPNOTSUPP - the referenced socket is not a type that supports the listen method

See

  • listen manual pages on unix-based systems

  • listen function in Microsoft's Winsock functions reference

VALUE
rsock_sock_listen(VALUE sock, VALUE log)
{
    rb_io_t *fptr;
    int backlog;

    backlog = NUM2INT(log);
    GetOpenFile(sock, fptr);
    if (listen(fptr->fd, backlog) < 0)
        rb_sys_fail("listen(2)");

    return INT2FIX(0);
}
recvfrom(maxlen) → [mesg, sender_addrinfo] Show source
recvfrom(maxlen, flags) → [mesg, sender_addrinfo]

Receives up to maxlen bytes from socket. flags is zero or more of the MSG_ options. The first element of the results, mesg, is the data received. The second element, sender_addrinfo, contains protocol-specific address information of the sender.

Parameters

  • maxlen - the maximum number of bytes to receive from the socket

  • flags - zero or more of the MSG_ options

Example

# In one file, start this first
require 'socket'
include Socket::Constants
socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' )
socket.bind( sockaddr )
socket.listen( 5 )
client, client_addrinfo = socket.accept
data = client.recvfrom( 20 )[0].chomp
puts "I only received 20 bytes '#{data}'"
sleep 1
socket.close

# In another file, start this second
require 'socket'
include Socket::Constants
socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' )
socket.connect( sockaddr )
socket.puts "Watch this get cut short!"
socket.close

Unix-based Exceptions

On unix-based based systems the following system exceptions may be raised if the call to recvfrom fails:

  • Errno::EAGAIN - the socket file descriptor is marked as O_NONBLOCK and no data is waiting to be received; or MSG_OOB is set and no out-of-band data is available and either the socket file descriptor is marked as O_NONBLOCK or the socket does not support blocking to wait for out-of-band-data

  • Errno::EWOULDBLOCK - see Errno::EAGAIN

  • Errno::EBADF - the socket is not a valid file descriptor

  • Errno::ECONNRESET - a connection was forcibly closed by a peer

  • Errno::EFAULT - the socket's internal buffer, address or address length cannot be accessed or written

  • Errno::EINTR - a signal interrupted recvfrom before any data was available

  • Errno::EINVAL - the MSG_OOB flag is set and no out-of-band data is available

  • Errno::EIO - an i/o error occurred while reading from or writing to the filesystem

  • Errno::ENOBUFS - insufficient resources were available in the system to perform the operation

  • Errno::ENOMEM - insufficient memory was available to fulfill the request

  • Errno::ENOSR - there were insufficient STREAMS resources available to complete the operation

  • Errno::ENOTCONN - a receive is attempted on a connection-mode socket that is not connected

  • Errno::ENOTSOCK - the socket does not refer to a socket

  • Errno::EOPNOTSUPP - the specified flags are not supported for this socket type

  • Errno::ETIMEDOUT - the connection timed out during connection establishment or due to a transmission timeout on an active connection

Windows Exceptions

On Windows systems the following system exceptions may be raised if the call to recvfrom fails:

  • Errno::ENETDOWN - the network is down

  • Errno::EFAULT - the internal buffer and from parameters on socket are not part of the user address space, or the internal fromlen parameter is too small to accommodate the peer address

  • Errno::EINTR - the (blocking) call was cancelled by an internal call to the WinSock function WSACancelBlockingCall

  • Errno::EINPROGRESS - a blocking Windows Sockets 1.1 call is in progress or the service provider is still processing a callback function

  • Errno::EINVAL - socket has not been bound with a call to bind, or an unknown flag was specified, or MSG_OOB was specified for a socket with SO_OOBINLINE enabled, or (for byte stream-style sockets only) the internal len parameter on socket was zero or negative

  • Errno::EISCONN - socket is already connected. The call to recvfrom is not permitted with a connected socket on a socket that is connection oriented or connectionless.

  • Errno::ENETRESET - the connection has been broken due to the keep-alive activity detecting a failure while the operation was in progress.

  • Errno::EOPNOTSUPP - MSG_OOB was specified, but socket is not stream-style such as type SOCK_STREAM. OOB data is not supported in the communication domain associated with socket, or socket is unidirectional and supports only send operations

  • Errno::ESHUTDOWN - socket has been shutdown. It is not possible to call recvfrom on a socket after shutdown has been invoked.

  • Errno::EWOULDBLOCK - socket is marked as nonblocking and a call to recvfrom would block.

  • Errno::EMSGSIZE - the message was too large to fit into the specified buffer and was truncated.

  • Errno::ETIMEDOUT - the connection has been dropped, because of a network failure or because the system on the other end went down without notice

  • Errno::ECONNRESET - the virtual circuit was reset by the remote side executing a hard or abortive close. The application should close the socket; it is no longer usable. On a UDP-datagram socket this error indicates a previous send operation resulted in an ICMP Port Unreachable message.

static VALUE
sock_recvfrom(int argc, VALUE *argv, VALUE sock)
{
    return rsock_s_recvfrom(sock, argc, argv, RECV_SOCKET);
}
recvfrom_nonblock(maxlen[, flags[, outbuf[, opts]]]) → [mesg, sender_addrinfo] Show source

Receives up to maxlen bytes from socket using recvfrom(2) after O_NONBLOCK is set for the underlying file descriptor. flags is zero or more of the MSG_ options. The first element of the results, mesg, is the data received. The second element, sender_addrinfo, contains protocol-specific address information of the sender.

When recvfrom(2) returns 0, #recvfrom_nonblock returns an empty string as data. The meaning depends on the socket: EOF on TCP, empty packet on UDP, etc.

Parameters

  • maxlen - the maximum number of bytes to receive from the socket

  • flags - zero or more of the MSG_ options

  • outbuf - destination String buffer

  • opts - keyword hash, supporting `exception: false`

Example

# In one file, start this first
require 'socket'
include Socket::Constants
socket = Socket.new(AF_INET, SOCK_STREAM, 0)
sockaddr = Socket.sockaddr_in(2200, 'localhost')
socket.bind(sockaddr)
socket.listen(5)
client, client_addrinfo = socket.accept
begin # emulate blocking recvfrom
  pair = client.recvfrom_nonblock(20)
rescue IO::WaitReadable
  IO.select([client])
  retry
end
data = pair[0].chomp
puts "I only received 20 bytes '#{data}'"
sleep 1
socket.close

# In another file, start this second
require 'socket'
include Socket::Constants
socket = Socket.new(AF_INET, SOCK_STREAM, 0)
sockaddr = Socket.sockaddr_in(2200, 'localhost')
socket.connect(sockaddr)
socket.puts "Watch this get cut short!"
socket.close

Refer to #recvfrom for the exceptions that may be thrown if the call to recvfrom_nonblock fails.

#recvfrom_nonblock may raise any error corresponding to recvfrom(2) failure, including Errno::EWOULDBLOCK.

If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN, it is extended by IO::WaitReadable. So IO::WaitReadable can be used to rescue the exceptions for retrying recvfrom_nonblock.

By specifying a keyword argument exception to false, you can indicate that #recvfrom_nonblock should not raise an IO::WaitReadable exception, but return the symbol :wait_readable instead.

See

# File ext/socket/lib/socket.rb, line 520
def recvfrom_nonblock(len, flag = 0, str = nil, exception: true)
  __recvfrom_nonblock(len, flag, str, exception)
end
sysaccept → [client_socket_fd, client_addrinfo] Show source

Accepts an incoming connection returning an array containing the (integer) file descriptor for the incoming connection, client_socket_fd, and an Addrinfo, client_addrinfo.

Example

# In one script, start this first
require 'socket'
include Socket::Constants
socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' )
socket.bind( sockaddr )
socket.listen( 5 )
client_fd, client_addrinfo = socket.sysaccept
client_socket = Socket.for_fd( client_fd )
puts "The client said, '#{client_socket.readline.chomp}'"
client_socket.puts "Hello from script one!"
socket.close

# In another script, start this second
require 'socket'
include Socket::Constants
socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' )
socket.connect( sockaddr )
socket.puts "Hello from script 2."
puts "The server said, '#{socket.readline.chomp}'"
socket.close

Refer to #accept for the exceptions that may be thrown if the call to sysaccept fails.

See

static VALUE
sock_sysaccept(VALUE sock)
{
    rb_io_t *fptr;
    VALUE sock2;
    union_sockaddr buf;
    socklen_t len = (socklen_t)sizeof buf;

    GetOpenFile(sock, fptr);
    sock2 = rsock_s_accept(0,fptr->fd,&buf.addr,&len);

    return rb_assoc_new(sock2, rsock_io_socket_addrinfo(sock2, &buf.addr, len));
}

Ruby Core © 1993–2017 Yukihiro Matsumoto
Licensed under the Ruby License.
Ruby Standard Library © contributors
Licensed under their own licenses.