131 lines
5.5 KiB
C
131 lines
5.5 KiB
C
/* libresolv interfaces for internal use across glibc.
|
|
Copyright (C) 2016-2022 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#ifndef _RESOLV_INTERNAL_H
|
|
#define _RESOLV_INTERNAL_H 1
|
|
|
|
#include <resolv.h>
|
|
#include <stdbool.h>
|
|
|
|
/* Resolver flags. Used for _flags in struct __res_state. */
|
|
#define RES_F_VC 0x00000001 /* Socket is TCP. */
|
|
#define RES_F_CONN 0x00000002 /* Socket is connected. */
|
|
#define RES_F_EDNS0ERR 0x00000004 /* EDNS0 caused errors. */
|
|
|
|
/* The structure HEADER is normally aligned on a word boundary. In
|
|
some code, we need to access this structure when it may be aligned
|
|
on a byte boundary. To avoid unaligned accesses, we need a typedef
|
|
with alignment one. This ensures the fields are accessed with byte
|
|
loads and stores. */
|
|
typedef HEADER __attribute__ ((__aligned__(1))) UHEADER;
|
|
|
|
/* Legacy function. This needs to be removed once all NSS modules
|
|
have been adjusted. */
|
|
static inline bool
|
|
res_use_inet6 (void)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
enum
|
|
{
|
|
/* The advertized EDNS buffer size. The value 1200 is derived
|
|
from the IPv6 minimum MTU (1280 bytes) minus some arbitrary
|
|
space for tunneling overhead. If the DNS server does not react
|
|
to ICMP Fragmentation Needed But DF Set messages, this should
|
|
avoid all UDP fragments on current networks. Avoiding UDP
|
|
fragments is desirable because it prevents fragmentation-based
|
|
spoofing attacks because the randomness in a DNS packet is
|
|
concentrated in the first fragment (with the headers) and does
|
|
not protect subsequent fragments. */
|
|
RESOLV_EDNS_BUFFER_SIZE = 1200,
|
|
};
|
|
|
|
struct resolv_context;
|
|
|
|
/* Internal function for implementing res_nmkquery and res_mkquery.
|
|
Also used by __res_context_query. */
|
|
int __res_context_mkquery (struct resolv_context *, int op, const char *dname,
|
|
int class, int type, const unsigned char *data,
|
|
unsigned char *buf, int buflen);
|
|
libc_hidden_proto (__res_context_mkquery)
|
|
|
|
/* Main resolver query function for use within glibc. */
|
|
int __res_context_search (struct resolv_context *, const char *, int, int,
|
|
unsigned char *, int, unsigned char **,
|
|
unsigned char **, int *, int *, int *);
|
|
libc_hidden_proto (__res_context_search)
|
|
|
|
/* Main resolver query function for use within glibc. */
|
|
int __res_context_query (struct resolv_context *, const char *, int, int,
|
|
unsigned char *, int, unsigned char **,
|
|
unsigned char **, int *, int *, int *);
|
|
libc_hidden_proto (__res_context_query)
|
|
|
|
/* Internal function used to implement the query and search
|
|
functions. */
|
|
int __res_context_send (struct resolv_context *, const unsigned char *, int,
|
|
const unsigned char *, int, unsigned char *,
|
|
int, unsigned char **, unsigned char **,
|
|
int *, int *, int *);
|
|
libc_hidden_proto (__res_context_send)
|
|
|
|
/* Return true if the query has been handled in RES_NOAAAA mode. For
|
|
that, RES_NOAAAA must be active, and the question type must be AAAA.
|
|
The caller is expected to return *RESULT as the return value. */
|
|
bool __res_handle_no_aaaa (struct resolv_context *ctx,
|
|
const unsigned char *buf, int buflen,
|
|
unsigned char *ans, int anssiz, int *result)
|
|
attribute_hidden;
|
|
|
|
/* Internal function similar to res_hostalias. */
|
|
const char *__res_context_hostalias (struct resolv_context *,
|
|
const char *, char *, size_t);
|
|
libc_hidden_proto (__res_context_hostalias);
|
|
|
|
/* Add an OPT record to a DNS query. */
|
|
int __res_nopt (struct resolv_context *, int n0,
|
|
unsigned char *buf, int buflen, int anslen);
|
|
libc_hidden_proto (__res_nopt)
|
|
|
|
/* Convert from presentation format (which usually means ASCII
|
|
printable) to network format (which is usually some kind of binary
|
|
format). The input is in the range [SRC, SRC + SRCLEN). The
|
|
output is written to DST (which has to be 4 or 16 bytes long,
|
|
depending on AF). Return 0 for invalid input, 1 for success, -1
|
|
for an invalid address family. */
|
|
int __inet_pton_length (int af, const char *src, size_t srclen, void *);
|
|
libc_hidden_proto (__inet_pton_length)
|
|
|
|
/* Called as part of the thread shutdown sequence. */
|
|
void __res_thread_freeres (void) attribute_hidden;
|
|
|
|
/* The Linux kernel does not enable all ICMP messages on a UDP socket
|
|
by default. A call this function enables full error reporting for
|
|
the socket FD. FAMILY must be AF_INET or AF_INET6. Returns 0 on
|
|
success, -1 on failure. */
|
|
int __res_enable_icmp (int family, int fd) attribute_hidden;
|
|
|
|
|
|
/* Returns the name server address for the indicated index. */
|
|
struct sockaddr *__res_get_nsaddr (res_state statp, unsigned int n);
|
|
libc_hidden_proto (__res_get_nsaddr)
|
|
|
|
|
|
#endif /* _RESOLV_INTERNAL_H */
|