getnetent,
getnetbyaddr,
getnetbyname,
setnetent,
endnetent —
get network entry
#include
<netdb.h>
struct netent *
getnetent(
void);
struct netent *
getnetbyname(
const
char *name);
struct netent *
getnetbyaddr(
in_addr_t
net,
int
type);
void
setnetent(
int
stayopen);
void
endnetent(
void);
The
getnetbyname() and
getnetbyaddr() functions return a pointer
to an object with the following structure:
struct netent {
char *n_name; /* official name of net */
char **n_aliases; /* alias list */
int n_addrtype; /* net number type */
in_addr_t n_net; /* net number */
};
The members of this structure are:
-
-
- n_name
- The official name of the network.
-
-
- n_aliases
- A null-terminated list of alternate names for the network.
-
-
- n_addrtype
- The type of the network number returned; it is always
AF_INET.
-
-
- n_net
- The network number. Network numbers are returned in machine byte
order.
On
OpenBSD, these legacy functions perform a lookup in a
similar fashion as
gethostbyname(3) and
gethostbyaddr(3),
respectively. On other systems, they may use a separate network database file,
/etc/networks.
In contrast to
gethostbyaddr(3), the
net argument is expected in machine byte
order.
The
setnetent(),
getnetent(), and
endnetent() functions are deprecated and no
longer have any effect. They could be used in the past to iterate over entries
in the former file
/etc/networks.
The
getnetbyaddr() and
getnetbyname() functions return
NULL if the requested entry is not found.
The
getnetent() function always returns
NULL.
- /etc/hosts
- The local host and network name database.
getaddrinfo(3),
gethostbyname(3),
getnameinfo(3),
resolver(3),
hosts(5)
These functions conform to
IEEE Std 1003.1-2008
(“POSIX.1”).
The
getnetent(),
getnetbyaddr(),
getnetbyname(),
setnetent(), and
endnetent() functions appeared in
4.2BSD.
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 functions
overwrite it. Only Internet network numbers are currently understood.
Expecting network numbers to fit in no more than 32 bits is naive.
![[OpenBSD]](/openbsd.gif){kind=small}