/* $NetBSD: getnameinfo.c,v 1.8 2025/02/06 20:59:00 christos Exp $ */
/*
* Copyright (c) 2025 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Attaullah Ansari.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: getnameinfo.c,v 1.8 2025/02/06 20:59:00 christos Exp $");
#endif
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netatalk/at.h>
#include <sys/un.h>
#include <net/if_dl.h>
#include <arpa/inet.h>
#include <assert.h>
#include <err.h>
#include <errno.h>
#include <netdb.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "support.h"
/*
* getnameinfo: Resolve IP addresses and ports to hostnames and service names,
* similar to the getnameinfo function in the standard library.
*
* usage:
* getnameinfo [-46FHNnrSu] [-f family] [-p port] <IP-address>
*
* -4: Restrict lookup to IPv4 addresses only
* -6: Restrict lookup to IPv6 addresses only
* -F: Suppress the fully-qualified domain name (FQDN)
* -f: Specify address family to look up
* -H: Display only the hostname, omitting the service name
* -N: Display the numeric service name instead of the service name
* -n: Display the numeric host address instead of the hostname
* -p: Specify the port number to be used in the lookup
* -r: Ensure that the name is returned (error if no name is found)
* -S: Display only the service name, omitting the hostname
* -u: Use UDP instead of the default TCP
*/
static void usage(void) __dead;
static void print_result(bool, bool, char *, char *);
static in_port_t get_port(const char *);
static uint8_t get_family_from_address(const char *);
static uint8_t get_family(const char *);
static void parse_atalk(const char *, struct sockaddr_at *);
int
main(int argc, char **argv)
{
socklen_t hostlen = NI_MAXHOST, servlen = NI_MAXSERV, addrlen;
char hostname[NI_MAXHOST], service[NI_MAXSERV];
bool hostname_only = false, service_only = false;
uint8_t family = AF_UNSPEC;
int flags = 0;
char *address = NULL;
in_port_t port = 0;
struct sockaddr_storage addr_st;
struct sockaddr_in *addr_in;
struct sockaddr_in6 *addr_in6;
struct sockaddr_un *addr_un;
struct sockaddr_dl *addr_dl;
int ch;
int error;
setprogname(argv[0]);
while ((ch = getopt(argc, argv, "46Ff:HNnp:rSu")) != -1) {
switch (ch) {
case '4':
if (family != AF_UNSPEC)
goto opt46f;
family = AF_INET;
break;
case '6':
if (family != AF_UNSPEC)
goto opt46f;
family = AF_INET6;
break;
case 'r':
flags |= NI_NAMEREQD;
break;
case 'u':
flags |= NI_DGRAM;
break;
case 'f':
if (family != AF_UNSPEC)
goto opt46f;
family = get_family(optarg);
break;
case 'F':
flags |= NI_NOFQDN;
break;
case 'n':
flags |= NI_NUMERICHOST;
break;
case 'N':
flags |= NI_NUMERICSERV;
break;
case 'H':
if (service_only)
goto optHS;
hostname_only = true;
break;
case 'S':
if (hostname_only)
goto optHS;
service_only = true;
break;
case 'p':
port = get_port(optarg);
break;
case '?':
default:
usage();
}
}
argc -= optind;
argv += optind;
if (argc > 1) {
warnx("Too many addresses");
usage();
}
if (argc == 0 && (hostname_only ||
(!hostname_only && !service_only))) {
warnx("No IP address provided");
usage();
}
if (port == 0 && (service_only ||
(!hostname_only && !service_only))) {
warnx("No port number provided");
usage();
}
if (argc == 1) {
address = argv[0];
if (family == AF_UNSPEC)
family = get_family_from_address(address);
}
memset(&addr_st, 0, sizeof(addr_st));
switch (family) {
case AF_APPLETALK:
parse_atalk(address, (struct sockaddr_at *)&addr_st);
addrlen = sizeof(struct sockaddr_at *);
break;
case AF_INET:
addr_in = (struct sockaddr_in *)&addr_st;
addr_in->sin_family = family;
addr_in->sin_port = htons(port);
if (address == NULL) {
addr_in->sin_addr.s_addr = INADDR_ANY;
} else if (inet_pton(family, address, &addr_in->sin_addr)
== 0)
errx(EXIT_FAILURE, "Invalid IPv4 address: %s", address);
addrlen = sizeof(*addr_in);
break;
case AF_INET6:
addr_in6 = (struct sockaddr_in6 *)&addr_st;
addr_in6->sin6_family = family;
addr_in6->sin6_port = htons(port);
if (address == NULL) {
addr_in6->sin6_addr =
(struct in6_addr)IN6ADDR_ANY_INIT;
} else if (inet_pton(family, address, &addr_in6->sin6_addr)
== 0)
errx(EXIT_FAILURE, "Invalid IPv6 address: %s", address);
addrlen = sizeof(*addr_in6);
break;
case AF_LINK:
addr_dl = (struct sockaddr_dl *)&addr_st;
addr_dl->sdl_len = sizeof(addr_st);
link_addr(address, addr_dl);
addrlen = addr_dl->sdl_len;
break;
case AF_LOCAL:
addr_un = (struct sockaddr_un *)&addr_st;
addr_un->sun_family = family;
if (strlen(address) >= sizeof(addr_un->sun_path))
errx(EXIT_FAILURE, "Invalid AF_LOCAL address: %s",
address);
(void)strncpy(addr_un->sun_path, address,
sizeof(addr_un->sun_path));
addrlen = sizeof(*addr_un);
break;
default:
errx(EXIT_FAILURE, "Unsupported family %d", family);
}
if (hostname_only)
servlen = 0;
else if (service_only)
hostlen = 0;
error = getnameinfo((struct sockaddr *)&addr_st, addrlen,
hostname, hostlen, service, servlen, flags);
if (error)
errx(EXIT_FAILURE, "%s", gai_strerror(error));
print_result(hostname_only, service_only, hostname, service);
fflush(stdout);
return ferror(stdout) ? EXIT_FAILURE : EXIT_SUCCESS;
opt46f:
warnx("Options -4, -6, -f cannot be used together");
usage();
optHS:
warnx("Options -H and -S cannot be used together");
usage();
}
static void
parse_atalk(const char *address, struct sockaddr_at *addr_at)
{
int net, node, port;
if (sscanf(address, "%d:%d:%d", &net, &node, &port) != 3)
badat: errx(EXIT_FAILURE, "Invalid appletalk address: %s", address);
if (net < 0 || net > 0xFFFF || node < 0 || node > 0xFF ||
port < 0 || port > 0xFFFF)
goto badat;
addr_at->sat_family = AF_APPLETALK;
addr_at->sat_addr.s_net = htons((u_short)net);
addr_at->sat_addr.s_node = (u_char)node;
addr_at->sat_port = htons((u_short)port);
}
static uint8_t
get_family_from_address(const char *address)
{
struct in_addr ipv4_addr;
struct in6_addr ipv6_addr;
if (inet_pton(AF_INET, address, &ipv4_addr) == 1)
return AF_INET;
if (inet_pton(AF_INET6, address, &ipv6_addr) == 1)
return AF_INET6;
errx(EXIT_FAILURE, "Invalid addrsss %s", address);
}
static uint8_t
get_family(const char* str)
{
int fam;
if (!parse_af(str, &fam) || fam <= 0 || fam > 255)
errx(EXIT_FAILURE, "Invalid family %s", str);
return (int8_t)fam;
}
static in_port_t
get_port(const char *port_str)
{
int r;
const intmax_t port = strtoi(port_str, NULL, 0, 0, 65535, &r);
if (r)
errc(EXIT_FAILURE, r, "Invalid port number %s", port_str);
return (in_port_t)port;
}
static void
print_result(bool hostname_only, bool service_only,
char *hostname, char *service)
{
if (hostname_only)
printf("%s\n", hostname);
else if (service_only)
printf("%s\n", service);
else
printf("%s %s\n", hostname, service);
}
static void __dead
usage(void)
{
(void)fprintf(stderr, "Usage: %s", getprogname());
(void)fprintf(stderr, " [-46fHNnrSu] [-p port] [<IP-address>]\n");
exit(EXIT_FAILURE);
}
