res_findzonecut.c

DHCP服务器源码

			    ns_rr_class(rr) != class)
				continue;
			t = ns_rr_name(rr);
			switch (sect) {
			case ns_s_an:
				if (ns_samedomain(dname, t) == 0) {
					DPRINTF(("get_soa: %s'%s', '%s') == 0",
						 "ns_samedomain(", dname, t));
					return ISC_R_NOTZONE;
				}
				break;
			case ns_s_ns:
				if (ns_samename(dname, t) == 1 ||
				    ns_samedomain(dname, t) == 0) {
					DPRINTF(("get_soa: %smain('%s', '%s')",
						 "ns_samename() || !ns_samedo",
						 dname, t));
					return ISC_R_NOTZONE;
				}
				break;
			default:
				abort();
			}
			if (strlen(t) + 1 > zsize) {
				DPRINTF(("get_soa: zname(%d) too small (%d)",
					 zsize, strlen(t) + 1));
				return ISC_R_NOSPACE;
			}
			strcpy(zname, t);
			rdata = ns_rr_rdata(rr);
			rdlen = ns_rr_rdlen(rr);
			if (ns_name_uncompress((u_char *)resp,
					       ns_msg_end(msg), rdata,
					       mname, msize) < 0) {
				DPRINTF(("get_soa: %s failed",
					 "ns_name_uncompress"));
				return ISC_R_NOMEMORY;
			}
			rcode = save_ns(statp, &msg,
					ns_s_ns, zname, class, nsrrsp);
			if (rcode != ISC_R_SUCCESS) {
				DPRINTF(("get_soa: save_ns failed"));
				return rcode;
			}
			return ISC_R_SUCCESS;
		}

		/* If we're out of labels, then not even "." has an SOA! */
		if (*dname == '\0')
			break;

		/* Find label-terminating "."; top of loop will skip it. */
		while (*dname != '.') {
			if (*dname == '\\')
				if (*++dname == '\0') {
					return ISC_R_NOSPACE;
				}
			dname++;
		}
	}
	DPRINTF(("get_soa: out of labels"));
	return ISC_R_DESTADDRREQ;
}

static isc_result_t
get_ns(res_state statp, const char *zname, ns_class class, rrset_ns *nsrrsp) {
	double resp[NS_PACKETSZ / sizeof (double)];
	ns_msg msg;
	int n;
	isc_result_t rcode;

	/* Go and get the NS RRs for this zone. */
	rcode = do_query(statp, zname, class, ns_t_ns, resp, &msg, &n);
	if (rcode != ISC_R_SUCCESS) {
		DPRINTF(("get_ns: do_query('zname', %s) failed (%d)",
			 zname, p_class(class), rcode));
		return rcode;
	}

	/* Remember the NS RRs and associated A RRs that came back. */
	rcode = save_ns(statp, &msg, ns_s_an, zname, class, nsrrsp);
	if (rcode != ISC_R_SUCCESS) {
		DPRINTF(("get_ns save_ns('%s', %s) failed",
			 zname, p_class(class)));
		return rcode;
	}

	return ISC_R_SUCCESS;
}

static isc_result_t
get_glue(res_state statp, ns_class class, rrset_ns *nsrrsp) {
	rr_ns *nsrr, *nsrr_n;

	/* Go and get the A RRs for each empty NS RR on our list. */
	for (nsrr = ISC_LIST_HEAD(*nsrrsp); nsrr != NULL; nsrr = nsrr_n) {
		double resp[NS_PACKETSZ / sizeof (double)];
		ns_msg msg;
		int n;
		isc_result_t rcode;

		nsrr_n = ISC_LIST_NEXT(nsrr, link);

		if (ISC_LIST_EMPTY(nsrr->addrs)) {
			rcode = do_query(statp, nsrr->name, class, ns_t_a,
					 resp, &msg, &n);
			if (rcode != ISC_R_SUCCESS) {
			    DPRINTF(("get_glue: do_query('%s', %s') failed",
				     nsrr->name, p_class(class)));
			    return rcode;
			}
			if (n > 0) {
				DPRINTF((
			"get_glue: do_query('%s', %s') CNAME or DNAME found",
					 nsrr->name, p_class(class)));
			}
			rcode = save_a(statp, &msg, ns_s_an, nsrr->name, class,
				       &nsrr->addrs);
			if (rcode != ISC_R_SUCCESS) {
				DPRINTF(("get_glue: save_r('%s', %s) failed",
					 nsrr->name, p_class(class)));
				return rcode;
			}
			/* If it's still empty, it's just chaff. */
			if (ISC_LIST_EMPTY(nsrr->addrs)) {
				DPRINTF(("get_glue: removing empty '%s' NS",
					 nsrr->name));
				free_nsrr(nsrrsp, nsrr);
			}
		}
	}
	return ISC_R_SUCCESS;
}

static isc_result_t
save_ns(res_state statp, ns_msg *msg, ns_sect sect,
	const char *owner, ns_class class,
	rrset_ns *nsrrsp)
{
	int i;
	isc_result_t rcode;

	for (i = 0; i < ns_msg_count(*msg, sect); i++) {
		char tname[MAXDNAME];
		const u_char *rdata;
		rr_ns *nsrr;
		ns_rr rr;
		int rdlen;

		rcode = ns_parserr(msg, sect, i, &rr);
		if (rcode != ISC_R_SUCCESS) {
			DPRINTF(("save_ns: ns_parserr(%s, %d) failed",
				 p_section(sect, ns_o_query), i));
			return rcode;
		}
		if (ns_rr_type(rr) != ns_t_ns ||
		    ns_rr_class(rr) != class ||
		    ns_samename(ns_rr_name(rr), owner) != 1)
			continue;
		nsrr = find_ns(nsrrsp, ns_rr_name(rr));
		if (nsrr == NULL) {
			nsrr = malloc(sizeof *nsrr);
			if (nsrr == NULL) {
				DPRINTF(("save_ns: malloc failed"));
				return ISC_R_NOMEMORY;
			}
			rdata = ns_rr_rdata(rr);
			rdlen = ns_rr_rdlen(rr);
			if (ns_name_uncompress(ns_msg_base(*msg),
					       ns_msg_end(*msg), rdata,
					       tname, sizeof tname) < 0) {
				DPRINTF(("save_ns: ns_name_uncompress failed"));
				free(nsrr);
				return ISC_R_NOMEMORY;
			}
			nsrr->name = strdup(tname);
			if (nsrr->name == NULL) {
				DPRINTF(("save_ns: strdup failed"));
				free(nsrr);
				return ISC_R_NOMEMORY;
			}
			ISC_LIST_INIT(nsrr->addrs);
			ISC_LIST_APPEND(*nsrrsp, nsrr, link);
		}
		rcode = save_a(statp, msg, ns_s_ar,
			       nsrr->name, class, &nsrr->addrs);
		if (rcode != ISC_R_SUCCESS) {
			DPRINTF(("save_ns: save_r('%s', %s) failed",
				 nsrr->name, p_class(class)));
			return rcode;
		}
	}
	return ISC_R_SUCCESS;
}

static isc_result_t
save_a(res_state statp, ns_msg *msg, ns_sect sect,
       const char *owner, ns_class class,
       rrset_a *arrsp)
{
	int i;
	isc_result_t rcode;

	for (i = 0; i < ns_msg_count(*msg, sect); i++) {
		ns_rr rr;
		rr_a *arr;

		rcode = ns_parserr(msg, sect, i, &rr);
		if (rcode != ISC_R_SUCCESS) {
			DPRINTF(("save_a: ns_parserr(%s, %d) failed",
				 p_section(sect, ns_o_query), i));
			return rcode;
		}
		if (ns_rr_type(rr) != ns_t_a ||
		    ns_rr_class(rr) != class ||
		    ns_samename(ns_rr_name(rr), owner) != 1 ||
		    ns_rr_rdlen(rr) != NS_INADDRSZ)
			continue;
		arr = malloc(sizeof *arr);
		if (arr == NULL) {
			DPRINTF(("save_a: malloc failed"));
			return ISC_R_NOMEMORY;
		}
		memcpy(&arr->addr, ns_rr_rdata(rr), NS_INADDRSZ);
		ISC_LIST_APPEND(*arrsp, arr, link);
	}
	return ISC_R_SUCCESS;
}

static void
free_nsrrset(rrset_ns *nsrrsp) {
	rr_ns *nsrr;

	while ((nsrr = ISC_LIST_HEAD(*nsrrsp)) != NULL)
		free_nsrr(nsrrsp, nsrr);
}

static void
free_nsrr(rrset_ns *nsrrsp, rr_ns *nsrr) {
	rr_a *arr;

	while ((arr = ISC_LIST_HEAD(nsrr->addrs)) != NULL) {
		ISC_LIST_UNLINK(nsrr->addrs, arr, link);
		free(arr);
	}
	free((char *)nsrr->name);
	ISC_LIST_UNLINK(*nsrrsp, nsrr, link);
	free(nsrr);
}

static rr_ns *
find_ns(rrset_ns *nsrrsp, const char *dname) {
	rr_ns *nsrr;

	for (nsrr = ISC_LIST_HEAD(*nsrrsp);
	     nsrr != NULL; nsrr = ISC_LIST_NEXT(nsrr, link))
		if (ns_samename(nsrr->name, dname) == 1)
			return (nsrr);
	return (NULL);
}

static isc_result_t
do_query(res_state statp, const char *dname, ns_class class, ns_type qtype,
	 double *resp, ns_msg *msg, int *alias_count)
{
	double req[NS_PACKETSZ / sizeof (double)];
	int i;
	unsigned n;
	isc_result_t status;

	status = res_nmkquery(statp, ns_o_query, dname, class, qtype,
			      NULL, 0, NULL, req, NS_PACKETSZ, &n);
	if (status != ISC_R_SUCCESS) {
		DPRINTF(("do_query: res_nmkquery failed"));
		return status;
	}
	status = res_nsend(statp, req, n, resp, NS_PACKETSZ, &n);
	if (status != ISC_R_SUCCESS) {
		DPRINTF(("do_query: res_nsend failed"));
		return status;
	}
	if (n == 0) {
		DPRINTF(("do_query: res_nsend returned 0"));
		return ISC_R_NOTFOUND;
	}
	if (ns_initparse((u_char *)resp, n, msg) < 0) {
		DPRINTF(("do_query: ns_initparse failed"));
		return ISC_R_NOSPACE;
	}
	n = 0;
	for (i = 0; i < ns_msg_count(*msg, ns_s_an); i++) {
		ns_rr rr;

		status = ns_parserr(msg, ns_s_an, i, &rr);
		if (status != ISC_R_SUCCESS) {
			DPRINTF(("do_query: ns_parserr failed"));
			return status;
		}
		n += (ns_rr_class(rr) == class &&
		      (ns_rr_type(rr) == ns_t_cname ||
		       ns_rr_type(rr) == ns_t_dname));
	}
	if (alias_count)
		*alias_count = n;
	return ISC_R_SUCCESS;
}