cosmopolitan/libc/dns/getaddrinfo.c

93 lines
4.2 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/bits/safemacros.internal.h"
#include "libc/calls/calls.h"
#include "libc/dns/dns.h"
#include "libc/dns/hoststxt.h"
#include "libc/dns/resolvconf.h"
#include "libc/fmt/conv.h"
#include "libc/mem/mem.h"
#include "libc/sock/sock.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/af.h"
#include "libc/sysv/consts/ai.h"
#include "libc/sysv/consts/eai.h"
#include "libc/sysv/consts/inaddr.h"
#include "libc/sysv/errfuns.h"
/**
* Resolves address for internet name.
*
* @param name is either an ip string or a utf-8 hostname
* @param service is the port number as a string
* @param hints may be passed to specialize behavior (optional)
* @param res receives a pointer that must be freed with freeaddrinfo(),
* and won't be modified if -1 is returned
* @return 0 on success or EAI_xxx value
*/
int getaddrinfo(const char *name, const char *service,
const struct addrinfo *hints, struct addrinfo **res) {
int rc, port;
const char *canon;
struct addrinfo *ai;
port = 0;
if (!name && !service) return EAI_NONAME;
if (service && (port = parseport(service)) == -1) return EAI_NONAME;
if (!name && (hints->ai_flags & AI_CANONNAME)) return EAI_BADFLAGS;
if (!(ai = newaddrinfo(port))) return EAI_MEMORY;
if (service) ai->ai_addr4->sin_port = htons(port);
if (hints) {
ai->ai_socktype = hints->ai_socktype;
ai->ai_protocol = hints->ai_protocol;
}
if (!name) {
ai->ai_addr4->sin_addr.s_addr =
(hints && (hints->ai_flags & AI_PASSIVE) == AI_PASSIVE)
? INADDR_ANY
: INADDR_LOOPBACK;
return 0;
}
if (inet_pton(AF_INET, name, &ai->ai_addr4->sin_addr.s_addr) == 1) {
*res = ai;
return 0;
} else if (hints && (hints->ai_flags & AI_NUMERICHOST) == AI_NUMERICHOST) {
freeaddrinfo(ai);
return EAI_NONAME;
} else if (resolvehoststxt(gethoststxt(), AF_INET, name, ai->ai_addr,
sizeof(ai->ai_addr4), &canon) > 0) {
memcpy(ai->ai_canonname, canon, min(strlen(canon), DNS_NAME_MAX) + 1);
*res = ai;
return 0;
} else {
rc = resolvedns(getresolvconf(), AF_INET, name, ai->ai_addr,
sizeof(ai->ai_addr4));
if (rc > 0) {
*res = ai;
return 0;
}
freeaddrinfo(ai);
if (rc == 0) {
return EAI_NONAME;
} else {
return EAI_SYSTEM;
}
}
}