1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
/* Copyright (C) 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <netinet/ether.h>
#include <netinet/if_ether.h>
#include "../nss/nsswitch.h"
/* Because the `ethers' lookup does not fit so well in the scheme so
we define a dummy struct here which helps us to use the available
functions. */
struct etherent
{
const char *e_name;
struct ether_addr e_addr;
};
/* Type of the lookup function we need here. */
typedef int (*lookup_function) (const struct ether_addr *, struct etherent *,
char *, int);
int
ether_ntohost (char *hostname, const struct ether_addr *addr)
{
static service_user *startp = NULL;
static lookup_function start_fct;
service_user *nip;
lookup_function fct;
int no_more;
int result;
enum nss_status status = NSS_STATUS_UNAVAIL;
struct etherent etherent;
if (startp == NULL)
{
no_more = __nss_ethers_lookup (&nip, "getntohost_r", (void **) &fct);
if (no_more)
startp = (service_user *) -1;
else
{
startp = nip;
start_fct = fct;
}
}
else
{
fct = start_fct;
no_more = (nip = startp) == (service_user *) -1;
}
while (no_more == 0)
{
char buffer[1024];
status = (*fct) (addr, ðerent, buffer, sizeof buffer);
no_more = __nss_next (&nip, "getntohost_r", (void **) &fct, status, 0);
}
if (status == NSS_STATUS_SUCCESS)
/* XXX This is a potential cause of trouble because the size of
the HOSTNAME buffer is not known but the interface does not
provide this information. */
strcpy (hostname, etherent.e_name);
return status == NSS_STATUS_SUCCESS ? 0 : -1;
}
|
