dnsapi: Add DNS message parsing routines from BIND.

dlls/dnsapi/Makefile.in

@@ -10,6 +10,8 @@ EXTRALIBS = $(LIBUNICODE) @RESOLVLIBS@
 C_SRCS = \
 	main.c \
 	name.c \
+	ns_name.c \
+	ns_parse.c \
 	query.c \
 	record.c
 

dlls/dnsapi/dnsapi.h

@@ -137,3 +137,8 @@ static inline LPSTR dns_strdup_ua( const char *src )
     }
     return dst;
 }
+
+int dns_ns_initparse( const u_char *, int, ns_msg * );
+int dns_ns_parserr( ns_msg *, ns_sect, int, ns_rr * );
+int dns_ns_name_skip( const u_char **, const u_char * );
+int dns_ns_name_uncompress( const u_char *, const u_char *, const u_char *, char *, size_t );

dlls/dnsapi/ns_parse.c

+/*
+ * Copyright (c) 1996,1999 by Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ */
+
+#include "config.h"
+
+#include <sys/types.h>
+
+#ifdef HAVE_NETINET_IN_H
+# include <netinet/in.h>
+#endif
+#ifdef HAVE_ARPA_NAMESER_H
+# include <arpa/nameser.h>
+#endif
+
+#include <errno.h>
+#ifdef HAVE_RESOLV_H
+# include <resolv.h>
+#endif
+#include <string.h>
+
+/* Forward. */
+
+static void	setsection(ns_msg *msg, ns_sect sect);
+
+/* Macros. */
+
+#define RETERR(err) do { return (-1); } while (0)
+
+/* Public. */
+
+/* These need to be in the same order as the nres.h:ns_flag enum. */
+struct _ns_flagdata _ns_flagdata[16] = {
+	{ 0x8000, 15 },		/* qr. */
+	{ 0x7800, 11 },		/* opcode. */
+	{ 0x0400, 10 },		/* aa. */
+	{ 0x0200, 9 },		/* tc. */
+	{ 0x0100, 8 },		/* rd. */
+	{ 0x0080, 7 },		/* ra. */
+	{ 0x0040, 6 },		/* z. */
+	{ 0x0020, 5 },		/* ad. */
+	{ 0x0010, 4 },		/* cd. */
+	{ 0x000f, 0 },		/* rcode. */
+	{ 0x0000, 0 },		/* expansion (1/6). */
+	{ 0x0000, 0 },		/* expansion (2/6). */
+	{ 0x0000, 0 },		/* expansion (3/6). */
+	{ 0x0000, 0 },		/* expansion (4/6). */
+	{ 0x0000, 0 },		/* expansion (5/6). */
+	{ 0x0000, 0 },		/* expansion (6/6). */
+};
+
+int
+ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
+	const u_char *optr = ptr;
+
+	for ((void)NULL; count > 0; count--) {
+		int b, rdlength;
+
+		b = dn_skipname(ptr, eom);
+		if (b < 0)
+			RETERR(EMSGSIZE);
+		ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
+		if (section != ns_s_qd) {
+			if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
+				RETERR(EMSGSIZE);
+			ptr += NS_INT32SZ/*TTL*/;
+			NS_GET16(rdlength, ptr);
+			ptr += rdlength/*RData*/;
+		}
+	}
+	if (ptr > eom)
+		RETERR(EMSGSIZE);
+	return (ptr - optr);
+}
+
+int
+dns_ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
+	const u_char *eom = msg + msglen;
+	int i;
+
+	memset(handle, 0x5e, sizeof *handle);
+	handle->_msg = msg;
+	handle->_eom = eom;
+	if (msg + NS_INT16SZ > eom)
+		RETERR(EMSGSIZE);
+	NS_GET16(handle->_id, msg);
+	if (msg + NS_INT16SZ > eom)
+		RETERR(EMSGSIZE);
+	NS_GET16(handle->_flags, msg);
+	for (i = 0; i < ns_s_max; i++) {
+		if (msg + NS_INT16SZ > eom)
+			RETERR(EMSGSIZE);
+		NS_GET16(handle->_counts[i], msg);
+	}
+	for (i = 0; i < ns_s_max; i++)
+		if (handle->_counts[i] == 0)
+			handle->_sections[i] = NULL;
+		else {
+			int b = ns_skiprr(msg, eom, (ns_sect)i,
+					  handle->_counts[i]);
+
+			if (b < 0)
+				return (-1);
+			handle->_sections[i] = msg;
+			msg += b;
+		}
+	if (msg != eom)
+		RETERR(EMSGSIZE);
+	setsection(handle, ns_s_max);
+	return (0);
+}
+
+int
+dns_ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
+	int b;
+
+	/* Make section right. */
+	if (section < 0 || section >= ns_s_max)
+		RETERR(ENODEV);
+	if (section != handle->_sect)
+		setsection(handle, section);
+
+	/* Make rrnum right. */
+	if (rrnum == -1)
+		rrnum = handle->_rrnum;
+	if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
+		RETERR(ENODEV);
+	if (rrnum < handle->_rrnum)
+		setsection(handle, section);
+	if (rrnum > handle->_rrnum) {
+		b = ns_skiprr(handle->_ptr, handle->_eom, section,
+			      rrnum - handle->_rrnum);
+
+		if (b < 0)
+			return (-1);
+		handle->_ptr += b;
+		handle->_rrnum = rrnum;
+	}
+
+	/* Do the parse. */
+	b = dn_expand(handle->_msg, handle->_eom,
+		      handle->_ptr, rr->name, NS_MAXDNAME);
+	if (b < 0)
+		return (-1);
+	handle->_ptr += b;
+	if (handle->_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
+		RETERR(EMSGSIZE);
+	NS_GET16(rr->type, handle->_ptr);
+	NS_GET16(rr->rr_class, handle->_ptr);
+	if (section == ns_s_qd) {
+		rr->ttl = 0;
+		rr->rdlength = 0;
+		rr->rdata = NULL;
+	} else {
+		if (handle->_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
+			RETERR(EMSGSIZE);
+		NS_GET32(rr->ttl, handle->_ptr);
+		NS_GET16(rr->rdlength, handle->_ptr);
+		if (handle->_ptr + rr->rdlength > handle->_eom)
+			RETERR(EMSGSIZE);
+		rr->rdata = handle->_ptr;
+		handle->_ptr += rr->rdlength;
+	}
+	if (++handle->_rrnum > handle->_counts[(int)section])
+		setsection(handle, (ns_sect)((int)section + 1));
+
+	/* All done. */
+	return (0);
+}
+
+/* Private. */
+
+static void
+setsection(ns_msg *msg, ns_sect sect) {
+	msg->_sect = sect;
+	if (sect == ns_s_max) {
+		msg->_rrnum = -1;
+		msg->_ptr = NULL;
+	} else {
+		msg->_rrnum = 0;
+		msg->_ptr = msg->_sections[(int)sect];
+	}
+}