gethostbydns.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

				bp += nn;
				buflen -= nn;
			}

			bp += sizeof(align) - ((u_long)bp % sizeof(align));

			if (bp + n >= &hostbuf[sizeof hostbuf]) {
				dprintf("size (%d) too big\n", n);
				had_error++;
				continue;
			}
			if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
				if (!toobig++)
					dprintf("Too many addresses (%d)\n",
						MAXADDRS);
				cp += n;
				continue;
			}
			bcopy(cp, *hap++ = bp, n);
			bp += n;
			buflen -= n;
			cp += n;
			if (cp != erdata) {
				h_errno = NO_RECOVERY;
				return (NULL);
			}
			break;
		default:
			dprintf("Impossible condition (type=%d)\n", type);
			h_errno = NO_RECOVERY;
			return (NULL);
			/* BIND has abort() here, too risky on bad data */
		}
		if (!had_error)
			haveanswer++;
	}
	if (haveanswer) {
		*ap = NULL;
		*hap = NULL;
# if defined(RESOLVSORT)
		/*
		 * Note: we sort even if host can take only one address
		 * in its return structures - should give it the "best"
		 * address in that case, not some random one
		 */
		if (_res.nsort && haveanswer > 1 && qtype == T_A)
			addrsort(h_addr_ptrs, haveanswer);
# endif /*RESOLVSORT*/
		if (!host.h_name) {
			n = strlen(qname) + 1;	/* for the \0 */
			if (n > buflen || n >= MAXHOSTNAMELEN)
				goto no_recovery;
			strcpy(bp, qname);
			host.h_name = bp;
			bp += n;
			buflen -= n;
		}
		if (_res.options & RES_USE_INET6)
			_map_v4v6_hostent(&host, &bp, &buflen);
		h_errno = NETDB_SUCCESS;
		return (&host);
	}
 no_recovery:
	h_errno = NO_RECOVERY;
	return (NULL);
}

struct hostent *
__dns_getanswer(answer, anslen, qname, qtype)
	const char *answer;
	int anslen;
	const char *qname;
	int qtype;
{
	switch(qtype) {
	case T_AAAA:
		host.h_addrtype = AF_INET6;
		host.h_length = IN6ADDRSZ;
		break;
	case T_A:
	default:
		host.h_addrtype = AF_INET;
		host.h_length = INADDRSZ;
		break;
	}

	return(gethostanswer((const querybuf *)answer, anslen, qname, qtype));
}

struct hostent *
_gethostbydnsname(name, af)
	const char *name;
	int af;
{
	querybuf buf;
	register const char *cp;
	char *bp;
	int n, size, type, len;

	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
		h_errno = NETDB_INTERNAL;
		return (NULL);
	}

	switch (af) {
	case AF_INET:
		size = INADDRSZ;
		type = T_A;
		break;
	case AF_INET6:
		size = IN6ADDRSZ;
		type = T_AAAA;
		break;
	default:
		h_errno = NETDB_INTERNAL;
		errno = EAFNOSUPPORT;
		return (NULL);
	}

	host.h_addrtype = af;
	host.h_length = size;

	/*
	 * if there aren't any dots, it could be a user-level alias.
	 * this is also done in res_query() since we are not the only
	 * function that looks up host names.
	 */
	if (!strchr(name, '.') && (cp = __hostalias(name)))
		name = cp;

	/*
	 * disallow names consisting only of digits/dots, unless
	 * they end in a dot.
	 */
	if (isdigit((int)name[0]))
		for (cp = name;; ++cp) {
			if (!*cp) {
				if (*--cp == '.')
					break;
				/*
				 * All-numeric, no dot at the end.
				 * Fake up a hostent as if we'd actually
				 * done a lookup.
				 */
				if (inet_pton(af, name, host_addr) <= 0) {
					h_errno = HOST_NOT_FOUND;
					return (NULL);
				}
				strncpy(hostbuf, name, MAXDNAME);
				hostbuf[MAXDNAME] = '\0';
				bp = hostbuf + MAXDNAME;
				len = sizeof hostbuf - MAXDNAME;
				host.h_name = hostbuf;
				host.h_aliases = host_aliases;
				host_aliases[0] = NULL;
				h_addr_ptrs[0] = (char *)host_addr;
				h_addr_ptrs[1] = NULL;
				host.h_addr_list = h_addr_ptrs;
				if (_res.options & RES_USE_INET6)
					_map_v4v6_hostent(&host, &bp, &len);
				h_errno = NETDB_SUCCESS;
				return (&host);
			}
			if (!isdigit((int)*cp) && *cp != '.') 
				break;
		}
	if ((isxdigit((int)name[0]) && strchr(name, ':') != NULL) ||
	    name[0] == ':')
		for (cp = name;; ++cp) {
			if (!*cp) {
				if (*--cp == '.')
					break;
				/*
				 * All-IPv6-legal, no dot at the end.
				 * Fake up a hostent as if we'd actually
				 * done a lookup.
				 */
				if (inet_pton(af, name, host_addr) <= 0) {
					h_errno = HOST_NOT_FOUND;
					return (NULL);
				}
				strncpy(hostbuf, name, MAXDNAME);
				hostbuf[MAXDNAME] = '\0';
				bp = hostbuf + MAXDNAME;
				len = sizeof hostbuf - MAXDNAME;
				host.h_name = hostbuf;
				host.h_aliases = host_aliases;
				host_aliases[0] = NULL;
				h_addr_ptrs[0] = (char *)host_addr;
				h_addr_ptrs[1] = NULL;
				host.h_addr_list = h_addr_ptrs;
				h_errno = NETDB_SUCCESS;
				return (&host);
			}
			if (!isxdigit((int)*cp) && *cp != ':' && *cp != '.') 
				break;
		}

	if ((n = res_search(name, C_IN, type, buf.buf, sizeof(buf))) < 0) {
		dprintf("res_search failed (%d)\n", n);
		return (NULL);
	}
	return (gethostanswer(&buf, n, name, type));
}

struct hostent *
_gethostbydnsaddr(addr, len, af)
	const char *addr;	/* XXX should have been def'd as u_char! */
	int len, af;
{
	const u_char *uaddr = (const u_char *)addr;
	static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
	static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
	int n, size;
	querybuf buf;
	register struct hostent *hp;
	char qbuf[MAXDNAME+1], *qp;
#ifdef SUNSECURITY
	register struct hostent *rhp;
	char **haddr;
	u_long old_options;
	char hname2[MAXDNAME+1];
#endif /*SUNSECURITY*/
	
	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
		h_errno = NETDB_INTERNAL;
		return (NULL);
	}
	if (af == AF_INET6 && len == IN6ADDRSZ &&
	    (!bcmp(uaddr, mapped, sizeof mapped) ||
	     !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
		/* Unmap. */
		addr += sizeof mapped;
		uaddr += sizeof mapped;
		af = AF_INET;
		len = INADDRSZ;
	}
	switch (af) {
	case AF_INET:
		size = INADDRSZ;
		break;
	case AF_INET6:
		size = IN6ADDRSZ;
		break;
	default:
		errno = EAFNOSUPPORT;
		h_errno = NETDB_INTERNAL;
		return (NULL);
	}
	if (size != len) {
		errno = EINVAL;
		h_errno = NETDB_INTERNAL;
		return (NULL);
	}
	switch (af) {
	case AF_INET:
		(void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
			       (uaddr[3] & 0xff),
			       (uaddr[2] & 0xff),
			       (uaddr[1] & 0xff),
			       (uaddr[0] & 0xff));
		break;
	case AF_INET6:
		qp = qbuf;
		for (n = IN6ADDRSZ - 1; n >= 0; n--) {
			qp += SPRINTF((qp, "%x.%x.",
				       uaddr[n] & 0xf,
				       (uaddr[n] >> 4) & 0xf));
		}
		strcpy(qp, "ip6.int");
		break;
	default:
		abort();
	}
	n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
	if (n < 0) {
		dprintf("res_query failed (%d)\n", n);
		return (NULL);
	}
	if (!(hp = gethostanswer(&buf, n, qbuf, T_PTR)))
		return (NULL);	/* h_errno was set by gethostanswer() */
#ifdef SUNSECURITY
	if (af == AF_INET) {
	    /*
	     * turn off search as the name should be absolute,
	     * 'localhost' should be matched by defnames
	     */
	    strncpy(hname2, hp->h_name, MAXDNAME);
	    hname2[MAXDNAME] = '\0';
	    old_options = _res.options;
	    _res.options &= ~RES_DNSRCH;
	    _res.options |= RES_DEFNAMES;
	    if (!(rhp = gethostbyname(hname2))) {
		syslog(LOG_NOTICE|LOG_AUTH,
		       "gethostbyaddr: No A record for %s (verifying [%s])",
		       hname2, inet_ntoa(*((struct in_addr *)addr)));
		_res.options = old_options;
		h_errno = HOST_NOT_FOUND;
		return (NULL);
	    }
	    _res.options = old_options;
	    for (haddr = rhp->h_addr_list; *haddr; haddr++)
		if (!memcmp(*haddr, addr, INADDRSZ))
			break;
	    if (!*haddr) {
		syslog(LOG_NOTICE|LOG_AUTH,
		       "gethostbyaddr: A record of %s != PTR record [%s]",
		       hname2, inet_ntoa(*((struct in_addr *)addr)));
		h_errno = HOST_NOT_FOUND;
		return (NULL);
	    }
	}
#endif /*SUNSECURITY*/
	hp->h_addrtype = af;
	hp->h_length = len;
	bcopy(addr, host_addr, len);
	h_addr_ptrs[0] = (char *)host_addr;
	h_addr_ptrs[1] = NULL;
	if (af == AF_INET && (_res.options & RES_USE_INET6)) {
		_map_v4v6_address((char*)host_addr, (char*)host_addr);
		hp->h_addrtype = AF_INET6;
		hp->h_length = IN6ADDRSZ;
	}
	h_errno = NETDB_SUCCESS;
	return (hp);
}

#ifdef RESOLVSORT
static void
addrsort(ap, num)
	char **ap;
	int num;
{
	int i, j;
	char **p;
	short aval[MAXADDRS];
	int needsort = 0;

	p = ap;
	for (i = 0; i < num; i++, p++) {
	    for (j = 0 ; (unsigned)j < _res.nsort; j++)
		if (_res.sort_list[j].addr.s_addr == 
		    (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
			break;
	    aval[i] = j;
	    if (needsort == 0 && i > 0 && j < aval[i-1])
		needsort = i;
	}
	if (!needsort)
	    return;

	while (needsort < num) {
	    for (j = needsort - 1; j >= 0; j--) {
		if (aval[j] > aval[j+1]) {
		    char *hp;

		    i = aval[j];
		    aval[j] = aval[j+1];
		    aval[j+1] = i;

		    hp = ap[j];
		    ap[j] = ap[j+1];
		    ap[j+1] = hp;

		} else
		    break;
	    }
	    needsort++;
	}
}
#endif
void
_sethostdnsent(stayopen)
	int stayopen;
{
	if ((_res.options & RES_INIT) == 0 && res_init() == -1)
		return;
	if (stayopen)
		_res.options |= RES_STAYOPEN | RES_USEVC;
}

void
_endhostdnsent()
{
	_res.options &= ~(RES_STAYOPEN | RES_USEVC);
	res_close();
}