Networking Databases

This section describes procedures which convert internet addresses and query various network databases. Care should be taken when using the database routines since they are not reentrant.

primitive: inet-aton address

Converts a string containing an Internet host address in the traditional dotted decimal notation into an integer.

(inet-aton "127.0.0.1") => 2130706433

primitive: inet-ntoa number

Converts an integer Internet host address into a string with the traditional dotted decimal representation.

(inet-ntoa 2130706433) => "127.0.0.1"

primitive: inet-netof address

Returns the network number part of the given integer Internet address.

(inet-netof 2130706433) => 127

primitive: inet-lnaof address

Returns the local-address-with-network part of the given Internet address.

(inet-lnaof 2130706433) => 1

primitive: inet-makeaddr net lna

Makes an Internet host address by combining the network number net with the local-address-within-network number lna.

(inet-makeaddr 127 1) => 2130706433

A host object is a structure that represents what is known about a network host, and is the usual way of representing a system's network identity inside software. The hostent functions accept a host object and return some information about that host's presence on the network.

procedure: hostent:name host

The "official" hostname for host.

procedure: hostent:aliases host

A list of aliases for host.

procedure: hostent:addrtype host

The host address type. For hosts with Internet addresses, this will return AF_INET.

procedure: hostent:length host

The length of each address for host, in bytes.

procedure: hostent:addr-list host

The list of network addresses associated with host.

The gethost functions are used to find a particular host's entry in the host database.

primitive: gethost [host]

procedure: gethostbyname hostname

procedure: gethostbyaddr address

Look up a host by name or address, and return a host object. The gethost procedure will accept either a string name or an integer address; if given no arguments, it behaves like gethostent (see below).

The following three procedures may be used to step through the host database from beginning to end. [FIXME: document the `sethost' variant of `sethostent'.]

procedure: sethostent

Initialize an internal stream from which host objects may be read. This procedure must be called before any calls to gethostent, and may also be called afterward to reset the host entry stream.

procedure: gethostent

Return the next host object from the host database, or #f if there are no more hosts to be found (or an error has been encountered). This procedure may not be used before sethostent has been called.

procedure: endhostent

Close the stream used by gethostent. The return value is unspecified.

The netent functions accept an object representing a network and return a selected component.

procedure: netent:name net

The "official" network name.

procedure: netent:aliases net

A list of aliases for the network.

procedure: netent:addrtype net

The type of the network number. Currently, this returns only AF_INET.

procedure: netent:net net

The network number.

The getnet procedures look up a particular network in the network database. Each returns a network object that describes the network's technical nature.

primitive: getnet [net]

procedure: getnetbyname net-name

procedure: getnetbyaddr net-number

Look up a network by name or net number in the network database. The net-name argument must be a string, and the net-number argument must be an integer. getnet will accept either type of argument, behaving like getnetent (see below) if no arguments are given.

[FIXME: document the `setnet' variant of `setnetent'.]

procedure: setnetent

Initializes a stream used by getnetent to read from the network database. The next use of getnetent will return the first entry. The return value is unspecified.

procedure: getnetent

Return the next entry from the network database.

procedure: endnetent

Close the stream used by getnetent. The return value is unspecified.

The protoent procedures accept an object representing a protocol and return a selected component.

procedure: protoent:name protocol

The "official" protocol name.

procedure: protoent:aliases protocol

A list of aliases for the protocol.

procedure: protoent:proto protocol

The protocol number.

The getproto procedures look up a particular network protocol and return a protocol object.

primitive: getproto [protocol]

procedure: getprotobyname name

procedure: getprotobynumber number

Look up a network protocol by name or by number. getprotobyname takes a string argument, and getprotobynumber takes an integer argument. getproto will accept either type, behaving like getprotoent (see below) if no arguments are supplied.

[FIXME: document the `setproto' variant of `setprotoent'.]

procedure: setprotoent

Initializes a stream used by getprotoent to read from the protocol database. The next use of getprotoent will return the first entry. The return value is unspecified.

procedure: getprotoent

Return the next entry from the protocol database.

procedure: endprotoent

Close the stream used by getprotoent. The return value is unspecified.

The servent procedures accept a service object and return some information about that service.

procedure: servent:name serv

The "official" name of the network service.

procedure: servent:aliases serv

A list of aliases for the network service.

procedure: servent:port serv

The Internet port used by the service.

procedure: servent:proto serv

The protocol used by the service. A service may be listed many times in the database under different protocol names.

The getserv procedures look up a network service and return a service object which describes the names and network ports conventionally assigned to the service.

primitive: getserv [name protocol]

procedure: getservbyname name protocol

procedure: getservbyport port protocol

Look up a network service by name or by service number, and return a network service object. The protocol argument specifies the name of the desired protocol; if the protocol found in the network service database does not match this name, a system error is signalled.

The getserv procedure will take either a service name or number as its first argument; if given no arguments, it behaves like getservent (see below).

[FIXME: document the `setserv' variant of `setservent'.]

procedure: setservent

Initializes a stream used by getservent to read from the services database. The next use of getservent will return the first entry. The return value is unspecified.

procedure: getservent

Return the next entry from the services database.

procedure: endservent

Close the stream used by getservent. The return value is unspecified.

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