1/* libresolv interfaces for internal use across glibc.
2 Copyright (C) 2016-2017 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#ifndef _RESOLV_INTERNAL_H
20#define _RESOLV_INTERNAL_H 1
21
22#include <resolv.h>
23#include <stdbool.h>
24
25/* Internal version of RES_USE_INET6 which does not trigger a
26 deprecation warning. */
27#define DEPRECATED_RES_USE_INET6 0x00002000
28
29static inline bool
30res_use_inet6 (void)
31{
32 return _res.options & DEPRECATED_RES_USE_INET6;
33}
34
35enum
36 {
37 /* The advertized EDNS buffer size. The value 1200 is derived
38 from the IPv6 minimum MTU (1280 bytes) minus some arbitrary
39 space for tunneling overhead. If the DNS server does not react
40 to ICMP Fragmentation Needed But DF Set messages, this should
41 avoid all UDP fragments on current networks. Avoiding UDP
42 fragments is desirable because it prevents fragmentation-based
43 spoofing attacks because the randomness in a DNS packet is
44 concentrated in the first fragment (with the headers) and does
45 not protect subsequent fragments. */
46 RESOLV_EDNS_BUFFER_SIZE = 1200,
47 };
48
49/* Add an OPT record to a DNS query. */
50int __res_nopt (res_state, int n0, unsigned char *buf, int buflen,
51 int anslen) attribute_hidden;
52
53/* Convert from presentation format (which usually means ASCII
54 printable) to network format (which is usually some kind of binary
55 format). The input is in the range [SRC, SRC + SRCLEN). The
56 output is written to DST (which has to be 4 or 16 bytes long,
57 depending on AF). Return 0 for invalid input, 1 for success, -1
58 for an invalid address family. */
59int __inet_pton_length (int af, const char *src, size_t srclen, void *);
60libc_hidden_proto (__inet_pton_length)
61
62#endif /* _RESOLV_INTERNAL_H */
63