address_families - socket address families (domains)

Description

The domain argument of the socket(2) specifies a communication domain; this selects the protocol family which will be used for communication. These families are defined in <sys/socket.h>. The formats currently understood by the Linux kernel include: AF_UNIXAF_LOCAL Local communication. For further information, see unix(7). AF_INET IPv4 Internet protocols. For further information, see ip(7). AF_AX25 Amateur radio AX.25 protocol. For further information, see ax25(4). AF_IPX IPX - Novell protocols. AF_APPLETALK AppleTalk For further information, see ddp(7). AF_NETROM AX.25 packet layer protocol. For further information, see netrom(4), ThePacketRadioProtocolsandLinux and the AX.25, NET/ROM, and ROSEnetworkprogramming chapters of the LinuxAmateurRadioAX.25HOWTO. AF_BRIDGE Can't be used for creating sockets; mostly used for bridge links in rtnetlink(7) protocol commands. AF_ATMPVC Access to raw ATM Permanent Virtual Circuits (PVCs). For further information, see the ATMonLinuxHOWTO. AF_X25 ITU-T X.25 / ISO/IEC 8208 protocol. For further information, see x25(7). AF_INET6 IPv6 Internet protocols. For further information, see ipv6(7). AF_ROSE RATS (Radio Amateur Telecommunications Society). Open Systems environment (ROSE) AX.25 packet layer protocol. For further information, see the resources listed for AF_NETROM. AF_DECnet DECet protocol sockets. See Documentation/networking/decnet.txt in the Linux kernel source tree for details. AF_NETBEUI Reserved for "802.2LLC project"; never used. AF_SECURITY This was a short-lived (between Linux 2.1.30 and 2.1.99pre2) protocol family for firewall upcalls. AF_KEY Key management protocol, originally developed for usage with IPsec (since Linux 2.1.38). This has no relation to keyctl(2) and the in-kernel key storage facility. See RFC 2367 PF_KEYKeyManagementAPI,Version2 for details. AF_NETLINK Kernel user interface device. For further information, see netlink(7). AF_PACKET Low-level packet interface. For further information, see packet(7). AF_ECONET Acorn Econet protocol (removed in Linux 3.5). See the Econet documentation for details. AF_ATMSVC Access to ATM Switched Virtual Circuits (SVCs) See the ATMonLinuxHOWTO for details. AF_RDS Reliable Datagram Sockets (RDS) protocol (since Linux 2.6.30). RDS over RDMA has no relation to AF_SMC or AF_XDP. For further information, see rds(7), rds-rdma(7), and Documentation/networking/rds.txt in the Linux kernel source tree. AF_IRDA Socket interface over IrDA (moved to staging in Linux 4.14, removed in Linux 4.17). For further information, see irda(7). AF_PPPOX Generic PPP transport layer, for setting up L2 tunnels (L2TP and PPPoE). See Documentation/networking/l2tp.txt in the Linux kernel source tree for details. AF_WANPIPE Legacy protocol for wide area network (WAN) connectivity that was used by Sangoma WAN cards (called "WANPIPE"); removed in Linux 2.6.21. AF_LLC Logical link control (IEEE 802.2 LLC) protocol, upper part of data link layer of ISO/OSI networking protocol stack (since Linux 2.4); has no relation to AF_PACKET. See chapter 13.5.3.LogicalLinkControl in UnderstandingLinuxKernelInternals (O'Reilly Media, 2006) and IEEEStandardsforLocalAreaNetworks:LogicalLinkControl (The Institute of Electronics and Electronics Engineers, Inc., New York, New York, 1985) for details. See also some historical notes regarding its development. AF_IB InfiniBand native addressing (since Linux 3.11). AF_MPLS Multiprotocol Label Switching (since Linux 4.1); mostly used for configuring MPLS routing via netlink(7), as it doesn't expose ability to create sockets to user space. AF_CAN Controller Area Network automotive bus protocol (since Linux 2.6.25). See Documentation/networking/can.rst in the Linux kernel source tree for details. AF_TIPC TIPC, "cluster domain sockets" protocol (since Linux 2.6.16). See TIPCProgrammer'sGuide and the protocol description for details. AF_BLUETOOTH Bluetooth low-level socket protocol (since Linux 3.11). See BluetoothManagementAPIoverview and AnIntroductiontoBluetoothProgramming by Albert Huang for details. AF_IUCV IUCV (inter-user communication vehicle) z/VM protocol for hypervisor-guest interaction (since Linux 2.6.21); has no relation to AF_VSOCK and/or AF_SMC See IUCVprotocoloverview for details. AF_RXRPC Rx, Andrew File System remote procedure call protocol (since Linux 2.6.22). See Documentation/networking/rxrpc.txt in the Linux kernel source tree for details. AF_ISDN New "modular ISDN" driver interface protocol (since Linux 2.6.27). See the mISDN wiki for details. AF_PHONET Nokia cellular modem IPC/RPC interface (since Linux 2.6.31). See Documentation/networking/phonet.txt in the Linux kernel source tree for details. AF_IEEE802154 IEEE 802.15.4 WPAN (wireless personal area network) raw packet protocol (since Linux 2.6.31). See Documentation/networking/ieee802154.txt in the Linux kernel source tree for details. AF_CAIF Ericsson's Communication CPU to Application CPU interface (CAIF) protocol (since Linux 2.6.36). See Documentation/networking/caif/Linux-CAIF.txt in the Linux kernel source tree for details. AF_ALG Interface to kernel crypto API (since Linux 2.6.38). See Documentation/crypto/userspace-if.rst in the Linux kernel source tree for details. AF_VSOCK VMWare VSockets protocol for hypervisor-guest interaction (since Linux 3.9); has no relation to AF_IUCV and AF_SMC. For further information, see vsock(7). AF_KCM KCM (kernel connection multiplexer) interface (since Linux 4.6). See Documentation/networking/kcm.txt in the Linux kernel source tree for details. AF_QIPCRTR Qualcomm IPC router interface protocol (since Linux 4.7). AF_SMC SMC-R (shared memory communications over RDMA) protocol (since Linux 4.11), and SMC-D (shared memory communications, direct memory access) protocol for intra-node z/VM quest interaction (since Linux 4.19); has no relation to AF_RDS, AF_IUCV or AF_VSOCK. See RFC 7609 IBM'sSharedMemoryCommunicationsoverRDMA(SMC-R)Protocol for details regarding SMC-R. See SMC-DReferenceInformation for details regarding SMC-D. AF_XDP XDP (express data path) interface (since Linux 4.18). See Documentation/networking/af_xdp.rst in the Linux kernel source tree for details.