Socket

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 Socket.new, there are several methods of socket creation for most cases.

TCP client socket: Socket.tcp, TCPSocket.open
TCP server socket: Socket.tcp_server_loop, TCPServer.open
UNIX client socket: Socket.unix, UNIXSocket.open
UNIX server socket: Socket.unix_server_loop, UNIXServer.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_ALG: Interface to kernel crypto API
AF_APPLETALK: AppleTalk protocol
AF_ATM: Asynchronous Transfer Mode
AF_AX25: AX.25 protocol
AF_BLUETOOTH: Bluetooth low-level socket protocol
AF_CAN: Controller Area Network automotive bus 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_DECnet: DECnet protocol
AF_DLI: DEC Direct Data Link Interface protocol
AF_E164: CCITT (ITU-T) E.164 recommendation
AF_ECMA: European Computer Manufacturers protocols
AF_HYLINK: NSC Hyperchannel protocol
AF_IB: InfiniBand native addressing
AF_IMPLINK: 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_KCM: KCM (kernel connection multiplexor) interface
AF_KEY: Key management protocol, originally developed for usage with IPsec
AF_LAT: Local Area Transport protocol
AF_LINK: Link layer interface
AF_LLC: Logical link control (IEEE 802.2 LLC) protocol
AF_LOCAL: Host-internal protocols
AF_MAX: Maximum address family for this platform
AF_MPLS: Multiprotocol Label Switching
AF_NATM: Native ATM access
AF_NDRV: Network driver raw access
AF_NETBIOS: NetBIOS
AF_NETGRAPH: Netgraph sockets
AF_NETLINK: Kernel user interface device
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_PPPOX: Generic PPP transport layer, for setting up L2 tunnels (L2TP and PPPoE)
AF_PUP: PARC Universal Packet protocol
AF_RDS: Reliable Datagram Sockets (RDS) protocol
AF_ROUTE: Internal routing protocol
AF_SIP: Simple Internet Protocol
AF_SNA: IBM SNA protocol
AF_SYSTEM
AF_TIPC: TIPC, “cluster domain sockets” protocol
AF_UNIX: UNIX sockets
AF_UNSPEC: Unspecified protocol, any supported address family
AF_VSOCK: VSOCK (originally “VMWare VSockets”) protocol for hypervisor-guest communication
AF_XDP: XDP (express data path) interface
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_ALG: Interface to kernel crypto API
PF_APPLETALK: AppleTalk protocol
PF_ATM: Asynchronous Transfer Mode
PF_AX25: AX.25 protocol
PF_BLUETOOTH: Bluetooth low-level socket protocol
PF_CAN: Controller Area Network automotive bus 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_DECnet: DECnet protocol
PF_DLI: DEC Direct Data Link Interface protocol
PF_ECMA: European Computer Manufacturers protocols
PF_HYLINK: NSC Hyperchannel protocol
PF_IB: InfiniBand native addressing
PF_IMPLINK: 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_KCM: KCM (kernel connection multiplexor) interface
PF_KEY: Key management protocol, originally developed for usage with IPsec
PF_LAT: Local Area Transport protocol
PF_LINK: Link layer interface
PF_LLC: Logical link control (IEEE 802.2 LLC) protocol
PF_LOCAL: Host-internal protocols
PF_MAX: Maximum address family for this platform
PF_MPLS: Multiprotocol Label Switching
PF_NATM: Native ATM access
PF_NDRV: Network driver raw access
PF_NETBIOS: NetBIOS
PF_NETGRAPH: Netgraph sockets
PF_NETLINK: Kernel user interface device
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_PPPOX: Generic PPP transport layer, for setting up L2 tunnels (L2TP and PPPoE)
PF_PUP: PARC Universal Packet protocol
PF_RDS: Reliable Datagram Sockets (RDS) protocol
PF_ROUTE: Internal routing protocol
PF_RTIP
PF_SIP: Simple Internet Protocol
PF_SNA: IBM SNA protocol
PF_SYSTEM
PF_TIPC: TIPC, “cluster domain sockets” protocol
PF_UNIX: UNIX sockets
PF_UNSPEC: Unspecified protocol, any supported address family
PF_VSOCK: VSOCK (originally “VMWare VSockets”) protocol for hypervisor-guest communication
PF_XDP: XDP (express data path) interface
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_CLOEXEC: Set the close-on-exec (FD_CLOEXEC) flag on the new file descriptor.
SOCK_DGRAM: A datagram socket provides connectionless, unreliable messaging
SOCK_NONBLOCK: Set the O_NONBLOCK file status flag on the open file description (see open(2)) referred to by the new file descriptor.
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: 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) click to toggle 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 socket/lib/socket.rb, line 800
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 click to toggle source

Obtains address information for nodename:servname.

Note that Addrinfo.getaddrinfo provides the same functionality in an object oriented style.

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 the 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 _)
{
    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 click to toggle source

Use Addrinfo#getnameinfo instead. This method is deprecated for the following reasons:

Uncommon address representation: 4/16-bytes binary string to represent IPv4/IPv6 address.
gethostbyaddr() may take a long time and it may block other threads. (GVL cannot be released since gethostbyname() is not thread safe.)
This method uses gethostbyname() function already removed from POSIX.

This method obtains the host information for address.

p Socket.gethostbyaddr([221,186,184,68].pack("CCCC"))
#=> ["carbon.ruby-lang.org", [], 2, "\xDD\xBA\xB8D"]

p Socket.gethostbyaddr([127,0,0,1].pack("CCCC"))
["localhost", [], 2, "\x7F\x00\x00\x01"]
p Socket.gethostbyaddr(([0]*15+[1]).pack("C"*16))
#=> ["localhost", ["ip6-localhost", "ip6-loopback"], 10,
     "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01"]

 
               static VALUE
sock_s_gethostbyaddr(int argc, VALUE *argv, VALUE _)
{
    VALUE addr, family;
    struct hostent *h;
    char **pch;
    VALUE ary, names;
    int t = AF_INET;

    rb_warn("Socket.gethostbyaddr is deprecated; use Addrinfo#getnameinfo instead.");

    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] click to toggle source

Use Addrinfo.getaddrinfo instead. This method is deprecated for the following reasons:

The 3rd element of the result is the address family of the first address. The address families of the rest of the addresses are not returned.
Uncommon address representation: 4/16-bytes binary string to represent IPv4/IPv6 address.
gethostbyname() may take a long time and it may block other threads. (GVL cannot be released since gethostbyname() is not thread safe.)
This method uses gethostbyname() function already removed from POSIX.

This method 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)
{
    rb_warn("Socket.gethostbyname is deprecated; use Addrinfo.getaddrinfo instead.");
    struct rb_addrinfo *res =
        rsock_addrinfo(host, Qnil, AF_UNSPEC, SOCK_STREAM, AI_CANONNAME);
    return rsock_make_hostent(host, res, sock_sockaddr);
}

gethostname => hostname click to toggle 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 Socket.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, ...] click to toggle 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] click to toggle source

Obtains name information for sockaddr.

sockaddr should be one of follows.

packed sockaddr string such as Socket.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 _)
{
    VALUE sa, af = Qnil, host = Qnil, port = Qnil, flags, tmp;
    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));
        }
        hints.ai_socktype = (fl & NI_DGRAM) ? SOCK_DGRAM : SOCK_STREAM;
        /* af */
        hints.ai_family = NIL_P(af) ? PF_UNSPEC : rsock_family_arg(af);
        res = rsock_getaddrinfo(host, port, &hints, 0);
        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_name:
    saved_errno = errno;
    if (res) rb_freeaddrinfo(res);
    errno = saved_errno;
    rsock_raise_socket_error("getnameinfo", error);

    UNREACHABLE_RETURN(Qnil);
}

getservbyname(service_name) => port_number click to toggle 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 _)
{
    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 click to toggle 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 _)
{
    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_str_new2(sp->s_name);
}

ip_address_list => array click to toggle 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 click to toggle 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 click to toggle 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);

    return addr;
}

pack_sockaddr_un(path) => sockaddr click to toggle 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));

    return addr;
}

pair(domain, type, protocol) => [socket1, socket2] click to toggle 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 click to toggle 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);

    return addr;
}

sockaddr_un(path) => sockaddr click to toggle 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));

    return addr;
}

socketpair(domain, type, protocol) => [socket1, socket2] click to toggle 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| ... } click to toggle 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.
:resolv_timeout: specify the name resolution 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 socket/lib/socket.rb, line 623
def self.tcp(host, port, local_host = nil, local_port = nil, connect_timeout: nil, resolv_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, timeout: resolv_timeout) {|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) click to toggle 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. Socket.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 socket/lib/socket.rb, line 856
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) click to toggle 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 socket/lib/socket.rb, line 756
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| ... } click to toggle 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 socket/lib/socket.rb, line 1026
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| ... } click to toggle source

Run UDP/IP server loop on the given sockets.

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

It calls the block for each message received.

 
               # File socket/lib/socket.rb, line 999
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| ... } click to toggle 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.

Socket.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 socket/lib/socket.rb, line 972
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) click to toggle 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 socket/lib/socket.rb, line 884
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
  }
  ip_list.uniq!(&:to_sockaddr)

  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) click to toggle 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 socket/lib/socket.rb, line 1076
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) click to toggle 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 socket/lib/socket.rb, line 1163
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) click to toggle 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 socket/lib/socket.rb, line 1106
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] click to toggle 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));
    return rb_assoc_new(INT2NUM(ntohs(sockaddr->sin_port)), host);
}

unpack_sockaddr_un(sockaddr) => path click to toggle 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));
    return path;
}

Public Instance Methods

accept => [client_socket, client_addrinfo] click to toggle 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 server)
{
    union_sockaddr buffer;
    socklen_t length = (socklen_t)sizeof(buffer);

    VALUE peer = rsock_s_accept(rb_cSocket, server, &buffer.addr, &length);

    return rb_assoc_new(peer, rsock_io_socket_addrinfo(peer, &buffer.addr, length));
}

accept_nonblock([options]) => [client_socket, client_addrinfo] click to toggle 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 Socket#accept for the exceptions that may be thrown if the call to accept_nonblock fails.

Socket#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¶ ↑

Socket#accept

 
               # File socket/lib/socket.rb, line 592
def accept_nonblock(exception: true)
  __accept_nonblock(exception)
end

bind(local_sockaddr) => 0 click to toggle 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 click to toggle 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 timed 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 timed 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, NULL);
    if (n < 0) {
        rsock_sys_fail_raddrinfo_or_sockaddr("connect(2)", addr, rai);
    }

    return INT2FIX(n);
}

connect_nonblock(remote_sockaddr, [options]) => 0 click to toggle 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 Socket#connect for the exceptions that may be thrown if the call to connect_nonblock fails.

Socket#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 socket/lib/socket.rb, line 1213
def connect_nonblock(addr, exception: true)
  __connect_nonblock(addr, exception)
end

ipv6only!() click to toggle source

enable the socket option IPV6_V6ONLY if IPV6_V6ONLY is available.

 
               # File socket/lib/socket.rb, line 463
def ipv6only!
  if defined? Socket::IPV6_V6ONLY
    self.setsockopt(:IPV6, :V6ONLY, 1)
  end
end

listen( int ) => 0 click to toggle 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] click to toggle 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] click to toggle 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, Socket#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 Socket#recvfrom for the exceptions that may be thrown if the call to recvfrom_nonblock fails.

Socket#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¶ ↑

Socket#recvfrom

 
               # File socket/lib/socket.rb, line 535
def recvfrom_nonblock(len, flag = 0, str = nil, exception: true)
  __recvfrom_nonblock(len, flag, str, exception)
end

sysaccept => [client_socket_fd, client_addrinfo] click to toggle 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 Socket#accept for the exceptions that may be thrown if the call to sysaccept fails.

See¶ ↑

Socket#accept

 
               static VALUE
sock_sysaccept(VALUE server)
{
    union_sockaddr buffer;
    socklen_t length = (socklen_t)sizeof(buffer);

    VALUE peer = rsock_s_accept(0, server, &buffer.addr, &length);

    return rb_assoc_new(peer, rsock_io_socket_addrinfo(peer, &buffer.addr, length));
}

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