383 lines
11 KiB
C
383 lines
11 KiB
C
/* $Id$ */
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/* Copyright 2005 by Dominick Meglio
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*
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* Permission to use, copy, modify, and distribute this
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* software and its documentation for any purpose and without
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* fee is hereby granted, provided that the above copyright
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* notice appear in all copies and that both that copyright
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* notice and this permission notice appear in supporting
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* documentation, and that the name of M.I.T. not be used in
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* advertising or publicity pertaining to distribution of the
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* software without specific, written prior permission.
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* M.I.T. makes no representations about the suitability of
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* this software for any purpose. It is provided "as is"
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* without express or implied warranty.
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*/
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#include "setup.h"
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#include <sys/types.h>
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#include <ctype.h>
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#if defined(WIN32) && !defined(WATT32)
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#include "nameser.h"
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#else
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <netdb.h>
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#include <arpa/inet.h>
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#include <arpa/nameser.h>
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#ifdef HAVE_ARPA_NAMESER_COMPAT_H
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#include <arpa/nameser_compat.h>
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#endif
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#endif
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#ifdef HAVE_NET_IF_H
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#include <net/if.h>
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#endif
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "ares.h"
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#include "ares_private.h"
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#include "ares_ipv6.h"
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#include "inet_ntop.h"
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#ifdef WATT32
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#undef WIN32
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#endif
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struct nameinfo_query {
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ares_nameinfo_callback callback;
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void *arg;
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union {
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struct sockaddr_in addr4;
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struct sockaddr_in6 addr6;
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} addr;
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int family;
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int flags;
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};
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#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
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#define IPBUFSIZ 40+IF_NAMESIZE
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#else
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#define IPBUFSIZ 40
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#endif
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static void nameinfo_callback(void *arg, int status, struct hostent *host);
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static char *lookup_service(unsigned short port, int flags,
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char *buf, size_t buflen);
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#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
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static void append_scopeid(struct sockaddr_in6 *addr6, unsigned int scopeid,
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char *buf, size_t buflen);
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#endif
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static char *ares_striendstr(const char *s1, const char *s2);
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void ares_getnameinfo(ares_channel channel, const struct sockaddr *sa, socklen_t salen,
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int flags, ares_nameinfo_callback callback, void *arg)
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{
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struct sockaddr_in *addr = NULL;
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struct sockaddr_in6 *addr6 = NULL;
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struct nameinfo_query *niquery;
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/* Verify the buffer size */
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if (salen == sizeof(struct sockaddr_in))
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addr = (struct sockaddr_in *)sa;
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else if (salen == sizeof(struct sockaddr_in6))
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addr6 = (struct sockaddr_in6 *)sa;
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else
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{
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callback(arg, ARES_ENOTIMP, NULL, NULL);
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return;
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}
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/* If neither, assume they want a host */
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if (!(flags & ARES_NI_LOOKUPSERVICE) && !(flags & ARES_NI_LOOKUPHOST))
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flags |= ARES_NI_LOOKUPHOST;
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/* All they want is a service, no need for DNS */
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if ((flags & ARES_NI_LOOKUPSERVICE) && !(flags & ARES_NI_LOOKUPHOST))
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{
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char buf[33], *service;
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unsigned int port = 0;
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if (salen == sizeof(struct sockaddr_in))
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port = addr->sin_port;
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else
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port = addr6->sin6_port;
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service = lookup_service(port, flags, buf, sizeof(buf));
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callback(arg, ARES_SUCCESS, NULL, service);
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return;
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}
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/* They want a host lookup */
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if ((flags & ARES_NI_LOOKUPHOST))
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{
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/* A numeric host can be handled without DNS */
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if ((flags & ARES_NI_NUMERICHOST))
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{
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unsigned int port = 0;
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char ipbuf[IPBUFSIZ];
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char srvbuf[33];
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char *service = NULL;
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ipbuf[0] = 0;
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/* Specifying not to lookup a host, but then saying a host
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* is required has to be illegal.
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*/
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if (flags & ARES_NI_NAMEREQD)
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{
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callback(arg, ARES_EBADFLAGS, NULL, NULL);
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return;
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}
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if (salen == sizeof(struct sockaddr_in6))
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{
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ares_inet_ntop(AF_INET6, &addr6->sin6_addr, ipbuf, IPBUFSIZ);
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port = addr6->sin6_port;
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/* If the system supports scope IDs, use it */
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#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
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append_scopeid(addr6, flags, ipbuf, sizeof(ipbuf));
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#endif
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}
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else
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{
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ares_inet_ntop(AF_INET, &addr->sin_addr, ipbuf, IPBUFSIZ);
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port = addr->sin_port;
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}
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/* They also want a service */
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if (flags & ARES_NI_LOOKUPSERVICE)
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service = lookup_service(port, flags, srvbuf, sizeof(srvbuf));
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callback(arg, ARES_SUCCESS, ipbuf, service);
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return;
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}
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/* This is where a DNS lookup becomes necessary */
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else
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{
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niquery = malloc(sizeof(struct nameinfo_query));
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if (!niquery)
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{
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callback(arg, ARES_ENOMEM, NULL, NULL);
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return;
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}
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niquery->callback = callback;
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niquery->arg = arg;
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niquery->flags = flags;
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if (sa->sa_family == AF_INET)
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{
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niquery->family = AF_INET;
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memcpy(&niquery->addr.addr4, addr, sizeof(addr));
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ares_gethostbyaddr(channel, &addr->sin_addr, sizeof(struct in_addr), AF_INET,
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nameinfo_callback, niquery);
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}
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else
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{
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niquery->family = AF_INET6;
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memcpy(&niquery->addr.addr6, addr6, sizeof(addr6));
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ares_gethostbyaddr(channel, &addr6->sin6_addr, sizeof(struct in6_addr), AF_INET6,
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nameinfo_callback, niquery);
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}
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}
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}
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}
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static void nameinfo_callback(void *arg, int status, struct hostent *host)
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{
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struct nameinfo_query *niquery = (struct nameinfo_query *) arg;
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char srvbuf[33];
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char *service = NULL;
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if (status == ARES_SUCCESS)
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{
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/* They want a service too */
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if (niquery->flags & ARES_NI_LOOKUPSERVICE)
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{
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if (niquery->family == AF_INET)
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service = lookup_service(niquery->addr.addr4.sin_port,
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niquery->flags, srvbuf, sizeof(srvbuf));
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else
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service = lookup_service(niquery->addr.addr6.sin6_port,
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niquery->flags, srvbuf, sizeof(srvbuf));
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}
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/* NOFQDN means we have to strip off the domain name portion.
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We do this by determining our own domain name, then searching the string
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for this domain name and removing it.
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*/
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if (niquery->flags & ARES_NI_NOFQDN)
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{
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char buf[255];
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char *domain;
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gethostname(buf, 255);
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if ((domain = strchr(buf, '.')))
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{
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char *end = ares_striendstr(host->h_name, domain);
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if (end)
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*end = 0;
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}
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}
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niquery->callback(niquery->arg, ARES_SUCCESS, host->h_name, service);
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return;
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}
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/* We couldn't find the host, but it's OK, we can use the IP */
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else if (status == ARES_ENOTFOUND && !(niquery->flags & ARES_NI_NAMEREQD))
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{
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char ipbuf[IPBUFSIZ];
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if (niquery->family == AF_INET)
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ares_inet_ntop(AF_INET, &niquery->addr.addr4.sin_addr, ipbuf, IPBUFSIZ);
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else
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{
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ares_inet_ntop(AF_INET6, &niquery->addr.addr6.sin6_addr, ipbuf, IPBUFSIZ);
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#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
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append_scopeid(&niquery->addr.addr6, niquery->flags, ipbuf, sizeof(ipbuf));
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#endif
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}
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/* They want a service too */
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if (niquery->flags & ARES_NI_LOOKUPSERVICE)
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{
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if (niquery->family == AF_INET)
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service = lookup_service(niquery->addr.addr4.sin_port,
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niquery->flags, srvbuf, sizeof(srvbuf));
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else
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service = lookup_service(niquery->addr.addr6.sin6_port,
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niquery->flags, srvbuf, sizeof(srvbuf));
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}
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niquery->callback(niquery->arg, ARES_SUCCESS, ipbuf, service);
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return;
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}
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niquery->callback(niquery->arg, status, NULL, NULL);
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free(niquery);
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}
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static char *lookup_service(unsigned short port, int flags,
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char *buf, size_t buflen)
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{
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const char *proto;
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struct servent *sep;
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#ifdef HAVE_GETSERVBYPORT_R
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struct servent se;
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#endif
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char tmpbuf[4096];
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if (port)
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{
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if (flags & ARES_NI_NUMERICSERV)
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sep = NULL;
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else
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{
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if (flags & ARES_NI_UDP)
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proto = "udp";
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else if (flags & ARES_NI_SCTP)
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proto = "sctp";
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else if (flags & ARES_NI_DCCP)
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proto = "dccp";
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else
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proto = "tcp";
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#ifdef HAVE_GETSERVBYPORT_R
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sep = &se;
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memset(tmpbuf, 0, sizeof(tmpbuf));
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#if GETSERVBYPORT_R_ARGS == 6
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if (getservbyport_r(port, proto, &se, (void *)tmpbuf, sizeof(tmpbuf), &sep) != 0)
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sep = NULL;
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#elif GETSERVBYPORT_R_ARGS == 5
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sep = getservbyport_r(port, proto, &se, (void *)tmpbuf, sizeof(tmpbuf));
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#elif GETSERVBYPORT_R_ARGS == 4
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if (getservbyport_r(port, proto, &se, (void *)tmpbuf) != 0)
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sep = NULL;
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#else
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/* Lets just hope the OS uses TLS! */
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sep = getservbyport(port, proto);
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#endif
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#else
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/* Lets just hope the OS uses TLS! */
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sep = getservbyport(port, proto);
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#endif
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}
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if (sep && sep->s_name)
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/* get service name */
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strcpy(tmpbuf, sep->s_name);
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else
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/* get port as a string */
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sprintf(tmpbuf, "%u", ntohs(port));
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if (strlen(tmpbuf) < buflen)
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/* return it if buffer big enough */
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strcpy(buf, tmpbuf);
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else
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/* avoid reusing previous one */
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buf[0] = '\0';
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return buf;
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}
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buf[0] = '\0';
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return NULL;
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}
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#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
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static void append_scopeid(struct sockaddr_in6 *addr6, unsigned int flags,
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char *buf, size_t buflen)
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{
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char fmt_u[] = "%u";
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char fmt_lu[] = "%lu";
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char tmpbuf[IF_NAMESIZE + 2];
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size_t bufl;
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char *fmt = (sizeof(addr6->sin6_scope_id) > sizeof(unsigned int))?fmt_lu:fmt_u;
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tmpbuf[0] = '%';
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#ifdef HAVE_IF_INDEXTONAME
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if ((flags & ARES_NI_NUMERICSCOPE) ||
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(!IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr)
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&& !IN6_IS_ADDR_MC_LINKLOCAL(&addr6->sin6_addr)))
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{
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sprintf(&tmpbuf[1], fmt, addr6->sin6_scope_id);
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}
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else
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{
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if (if_indextoname(addr6->sin6_scope_id, &tmpbuf[1]) == NULL)
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sprintf(&tmpbuf[1], fmt, addr6->sin6_scope_id);
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}
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#else
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sprintf(&tmpbuf[1], fmt, addr6->sin6_scope_id);
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(void) flags;
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#endif
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tmpbuf[IF_NAMESIZE + 1] = '\0';
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bufl = strlen(buf);
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if(bufl + strlen(tmpbuf) < buflen)
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/* only append the scopeid string if it fits in the target buffer */
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strcpy(&buf[bufl], tmpbuf);
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}
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#endif
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/* Determines if s1 ends with the string in s2 (case-insensitive) */
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static char *ares_striendstr(const char *s1, const char *s2)
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{
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const char *c1, *c2, *c1_begin;
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size_t s1_len = strlen(s1), s2_len = strlen(s2);
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/* If the substr is longer than the full str, it can't match */
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if (s2_len > s1_len)
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return NULL;
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/* Jump to the end of s1 minus the length of s2 */
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c1_begin = s1+s1_len-s2_len;
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c1 = (const char *)c1_begin;
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c2 = s2;
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while (c2 < s2+s2_len)
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{
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if (tolower(*c1) != tolower(*c2))
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return NULL;
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else
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{
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c1++;
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c2++;
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}
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}
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if (c2 == c1 && c2 == NULL)
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return (char *)c1_begin;
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return NULL;
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}
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