getnetbyaddr(3) - NetBSD Manual Pages

Command:
Section:
Arch:
Collection:
>>>
GETNETENT(3)            NetBSD Library Functions Manual           GETNETENT(3)


NAME

     getnetent, getnetbyaddr, getnetbyname, setnetent, endnetent -- get net-
     work entry


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <netdb.h>

     struct netent *
     getnetent();

     struct netent *
     getnetbyname(const char *name);

     struct netent *
     getnetbyaddr(uint32_t net, int type);

     void
     setnetent(int stayopen);

     void
     endnetent(void);


DESCRIPTION

     The getnetent(), getnetbyname(), and getnetbyaddr() functions each return
     a pointer to an object with the following structure containing the bro-
     ken-out fields of a line in the network data base as described in
     networks(5).

           struct  netent {
                   char            *n_name;        /* official name of net */
                   char            **n_aliases;    /* alias list */
                   int             n_addrtype;     /* net number type */
                   uint32_t        n_net;          /* net number */
           };

     The members of this structure are:

     n_name      The official name of the network.

     n_aliases   A zero terminated list of alternative names for the network.

     n_addrtype  The type of the network number returned; currently only
                 AF_INET.

     n_net       The network number.  Network numbers are returned in host
                 byte order.

     The getnetent() function reads the next line of the file, opening the
     file if necessary.

     The setnetent() function opens and rewinds the file.  If the stayopen
     flag is non-zero, the net data base will not be closed after each call to
     getnetbyname() or getnetbyaddr().

     The endnetent() function closes the file.

     The getnetbyname() and getnetbyaddr() functions sequentially search from
     the beginning of the file until a matching net name or net address and
     type is found, or until EOF is encountered.  Network numbers are supplied
     in host byte order.


FILES

     /etc/networks


RETURN VALUES

     Null pointer (NULL) returned on EOF or error.


SEE ALSO

     networks(5), nsswitch.conf(5)


HISTORY

     The getnetent(), getnetbyaddr(), getnetbyname(), setnetent(), and
     endnetent() functions appeared in 4.2BSD.


BUGS

     The data space used by these functions is static; if future use requires
     the data, it should be copied before any subsequent calls to these func-
     tions overwrite it.  Only Internet network numbers are currently under-
     stood.  Expecting network numbers to fit in no more than 32 bits is prob-
     ably naive.

NetBSD 10.1                    February 21, 2018                   NetBSD 10.1