mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-09 23:00:07 +00:00
75 lines
2.2 KiB
C
75 lines
2.2 KiB
C
/* Simple DNS record parser without textual name decoding.
|
|
Copyright (C) 2022-2024 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/>. */
|
|
|
|
#include <arpa/nameser.h>
|
|
#include <errno.h>
|
|
#include <stdbool.h>
|
|
#include <string.h>
|
|
|
|
bool
|
|
__ns_rr_cursor_next (struct ns_rr_cursor *c, struct ns_rr_wire *rr)
|
|
{
|
|
rr->rdata = NULL;
|
|
|
|
/* Extract the record owner name. */
|
|
int consumed = __ns_name_unpack (c->begin, c->end, c->current,
|
|
rr->rname, sizeof (rr->rname));
|
|
if (consumed < 0)
|
|
{
|
|
memset (rr, 0, sizeof (*rr));
|
|
__set_errno (EMSGSIZE);
|
|
return false;
|
|
}
|
|
c->current += consumed;
|
|
|
|
/* Extract the metadata. */
|
|
struct
|
|
{
|
|
uint16_t rtype;
|
|
uint16_t rclass;
|
|
uint32_t ttl;
|
|
uint16_t rdlength;
|
|
} __attribute__ ((packed)) metadata;
|
|
_Static_assert (sizeof (metadata) == 10, "sizeof metadata");
|
|
if (c->end - c->current < sizeof (metadata))
|
|
{
|
|
memset (rr, 0, sizeof (*rr));
|
|
__set_errno (EMSGSIZE);
|
|
return false;
|
|
}
|
|
memcpy (&metadata, c->current, sizeof (metadata));
|
|
c->current += sizeof (metadata);
|
|
/* Endianness conversion. */
|
|
rr->rtype = ntohs (metadata.rtype);
|
|
rr->rclass = ntohs (metadata.rclass);
|
|
rr->ttl = ntohl (metadata.ttl);
|
|
rr->rdlength = ntohs (metadata.rdlength);
|
|
|
|
/* Extract record data. */
|
|
if (c->end - c->current < rr->rdlength)
|
|
{
|
|
memset (rr, 0, sizeof (*rr));
|
|
__set_errno (EMSGSIZE);
|
|
return false;
|
|
}
|
|
rr->rdata = c->current;
|
|
c->current += rr->rdlength;
|
|
|
|
return true;
|
|
}
|