60 lines
2.9 KiB
C
60 lines
2.9 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
|
|
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
|
|
╞══════════════════════════════════════════════════════════════════════════════╡
|
|
│ Copyright 2020 Justine Alexandra Roberts Tunney │
|
|
│ │
|
|
│ This program is free software; you can redistribute it and/or modify │
|
|
│ it under the terms of the GNU General Public License as published by │
|
|
│ the Free Software Foundation; version 2 of the License. │
|
|
│ │
|
|
│ This program 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 │
|
|
│ General Public License for more details. │
|
|
│ │
|
|
│ You should have received a copy of the GNU General Public License │
|
|
│ along with this program; if not, write to the Free Software │
|
|
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
|
|
│ 02110-1301 USA │
|
|
╚─────────────────────────────────────────────────────────────────────────────*/
|
|
#include "libc/dns/dns.h"
|
|
#include "libc/str/str.h"
|
|
#include "libc/sysv/errfuns.h"
|
|
|
|
/**
|
|
* Writes dotted hostname to DNS message wire.
|
|
*
|
|
* The wire format is basically a sequence of Pascal strings, for each
|
|
* label in the name. We only do enough validation to maintain protocol
|
|
* invariants.
|
|
*
|
|
* @param name is a dotted NUL-terminated hostname string
|
|
* @return bytes written (excluding NUL) or -1 w/ errno
|
|
*/
|
|
int pascalifydnsname(uint8_t *buf, size_t size, const char *name) {
|
|
size_t i, j, k, namelen;
|
|
if ((namelen = strlen(name)) > DNS_NAME_MAX) return enametoolong();
|
|
i = 0;
|
|
if (size || namelen) {
|
|
if (namelen + 1 > size) return enospc();
|
|
buf[0] = '\0';
|
|
j = 0;
|
|
for (;;) {
|
|
for (k = 0; name[j + k] && name[j + k] != '.'; ++k) {
|
|
buf[i + k + 1] = name[j + k];
|
|
}
|
|
if (k) {
|
|
if (k > DNS_LABEL_MAX) return enametoolong();
|
|
buf[i] = k;
|
|
i += k + 1;
|
|
}
|
|
j += k + 1;
|
|
if (!name[j - 1]) {
|
|
break;
|
|
}
|
|
}
|
|
buf[i] = '\0';
|
|
}
|
|
return i;
|
|
}
|