netconfig(SFF)

Synopsis

#include <netconfig.h>

Description

The netconfig database and the routines that access it (see getnetconfig(SLIB)) are part of the Network Selection component. The Network Selection component also includes the environment variable NETPATH and a group of routines that access the netconfig database using NETPATH components as links to the netconfig entries. NETPATH is described in sh(C); the NETPATH access routines are discussed in getnetpath(SLIB).

Files

/etc/netconfig

/usr/include/netconfig.h

Usage

netconfig database fields

``network ID''

A string used to uniquely identify a network. The string consists of non-null characters, and has a length of at least 1. No maximum length is specified. This namespace is locally significant and the local system administrator is the naming authority. Note that all network IDs on a system must be unique.

``semantics''

A string identifying the semantics of the network (that is, the set of services it supports) by identifying the service interface it provides. The ``semantics'' field is mandatory. The following semantics are recognized.

tpi_clts

Transport Provider Interface, connectionless

tpi_cots

Transport Provider Interface, connection oriented

tpi_cots_ord

Transport Provider Interface, connection oriented, supports orderly release.

tpi_raw

Transport Provider Interface, raw

``flag''

This field records certain boolean attributes of networks. ``flag'' contains a string composed of a combination of characters, each of which indicates the value of the corresponding attribute. If the character is present, the attribute is true. If the character is absent, the attribute is false. A dash (-) indicates that none of the attributes is present. Two characters are currently recognized:

v

Visible (default) network. Used when the environment variable NETPATH is unset.

b

Enable RPC broadcast. The network will accept broadcasts. If this flag is not set, then broadcasts will not be allowed on the network. The flag must be set for UDP networks, otherwise some applications which need to broadcast will fail. Note that connection oriented transports do not support broadcasts.

``protocol family''

The ``protocol family'' (see also the ``protocol name'' field below) is provided for protocol-specific applications.

The ``protocol family'' field contains a string that identifies a protocol family. This string follows the same rules as those for the ``network ID'' field. A dash in this field indicates that no protocol family identifier applies: that is, the network is experimental. The following are examples:

loopback

Loopback (local to host).

inet

Internetwork: for example, UDP, TCP

implink

ARPANET IMP addresses

pup

PUP protocols: for example, BSP

chaos

MIT CHAOS protocols

ns

XEROX NS protocols

nbs

NBS protocols

ecma

European Computer Manufacturers Association

datakit

DATAKIT protocols

ccitt

CCITT protocols: for example, X.25

sna

IBM SNA

decnet

DECNET

dli

Direct data link interface

lat

LAT

hylink

NSC Hyperchannel

appletalk

Apple Talk

nit

Network Interface Tap

ieee802

IEEE 802.2; also ISO 8802

osi

Umbrella for all families used by OSI (for example, protosw lookup)

x25

CCITT X.25 in particular

osinet

AFI = 47, IDI = 4

gosip

U.S. Government OSI

``protocol name''

The ``protocol name'' field contains a string that identifies a protocol. This string follows the same rules as those for the ``network ID'' field. The following protocol names are recognized. A dash indicates that none of the names listed below applies:

tcp

Transmission Control Protocol

udp

User Datagram Protocol

icmp

Internet Control Message Protocol

``network device''

The ``network device'' is the full pathname of the device used to connect to the transport provider. Typically, this device will be in the /dev directory. This field must have an entry.

``directory lookup libraries''

These libraries support a directory service (that is, a name-to-address mapping service) for the network. This service is implemented by the name-to-address mapping feature. If a network is not provided with such a library, the netdir(SLIB) feature will not work. A dash in this field indicates the absence of any lookup libraries, in which case name-to-address mapping for the network is non-functional. This field consists of a comma-separated list of full pathnames to dynamically linked libraries. Commas may be embedded as ``\,''; backslashes as ``\\''.

netconfig structure members

char * nc_netid

Network ID, including NULL terminator

unsigned long nc_semantics

Semantics

unsigned long nc_flag

Flags

char * nc_protofmly

Protocol family

char * nc_proto

Protocol name

char * nc_device

Full pathname of the network device

unsigned long nc_nlookups

Number of directory lookup libraries

char ** nc_lookups

Full pathnames of the directory lookup libraries

unsigned long nc_unused[9]

Reserved for future expansion (not advertised at user level)

NC_TPI_CLTS

NC_TPI_COTS

NC_TPI_COTS_ORD

NC_TPI_RAW

The nc_flag variable is a bitfield. The NC_VISIBLE bit, corresponding to the attribute identified above, is currently recognized. NC_NOFLAG indicates the absence of any attributes.

References