resolv: Move res_queriesmatch to its own file and into libc

And reformat it to GNU style.

The treatment of this function matches res_nameinquery, for the
reasons stated there.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

include/resolv.h

@@ -54,7 +54,6 @@ libresolv_hidden_proto (__p_type)
 libresolv_hidden_proto (__loc_ntoa)
 libresolv_hidden_proto (__fp_nquery)
 libresolv_hidden_proto (__fp_query)
-libresolv_hidden_proto (__res_queriesmatch)
 libresolv_hidden_proto (__b64_ntop)
 libresolv_hidden_proto (__dn_count_labels)
 
@@ -68,6 +67,8 @@ extern __typeof (res_hnok) __libc_res_hnok;
 libc_hidden_proto (__libc_res_hnok)
 extern __typeof (__res_nameinquery) __libc_res_nameinquery;
 libc_hidden_proto (__libc_res_nameinquery)
+extern __typeof (__res_queriesmatch) __libc_res_queriesmatch;
+libc_hidden_proto (__libc_res_queriesmatch)
 
 # endif /* _RESOLV_H_ && !_ISOMAC */
 #endif

resolv/Makefile

@@ -53,6 +53,7 @@ routines := \
   res_init \
   res_libc \
   res_nameinquery \
+  res_queriesmatch \
   res_randomid \
   resolv_conf \
   resolv_context \

resolv/Versions

@@ -77,6 +77,7 @@ libc {
     __libc_res_dnok;
     __libc_res_hnok;
     __libc_res_nameinquery;
+    __libc_res_queriesmatch;
     __ns_name_compress;
     __ns_name_ntop;
     __ns_name_pack;

resolv/res_queriesmatch.c

@@ -0,0 +1,129 @@
+/* Check if two DNS packets contain the same query.
+   Copyright (C) 2016-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ * Copyright (c) 1985, 1989, 1993
+ *    The Regents of the University of California.  All rights reserved.
+ *
+ * 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.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+ */
+
+/*
+ * Portions Copyright (c) 1993 by Digital Equipment Corporation.
+ *
+ * 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, and that
+ * the name of Digital Equipment Corporation not be used in advertising or
+ * publicity pertaining to distribution of the document or software without
+ * specific, written prior permission.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
+ * CORPORATION 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.
+ */
+
+/*
+ * Portions 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 <resolv.h>
+
+/* Author: paul vixie, 29may94.  */
+int
+__libc_res_queriesmatch (const unsigned char *buf1, const unsigned char *eom1,
+                         const unsigned char *buf2, const unsigned char *eom2)
+{
+  if (eom1 - buf1 < HFIXEDSZ || eom2 - buf2 < HFIXEDSZ)
+    return -1;
+
+  /* Only header section present in replies to dynamic update
+     packets.  */
+  if ((((HEADER *) buf1)->opcode == ns_o_update) &&
+      (((HEADER *) buf2)->opcode == ns_o_update))
+    return 1;
+
+  /* Note that we initially do not convert QDCOUNT to the host byte
+     order.  We can compare it with the second buffer's QDCOUNT
+     value without doing this.  */
+  int qdcount = ((HEADER *) buf1)->qdcount;
+  if (qdcount != ((HEADER *) buf2)->qdcount)
+    return 0;
+
+  qdcount = htons (qdcount);
+  const unsigned char *cp = buf1 + HFIXEDSZ;
+
+  while (qdcount-- > 0)
+    {
+      char tname[MAXDNAME+1];
+      int n, ttype, tclass;
+
+      n = __libc_dn_expand (buf1, eom1, cp, tname, sizeof tname);
+      if (n < 0)
+        return -1;
+      cp += n;
+      if (eom1 - cp < 4)
+        return -1;
+      NS_GET16 (ttype, cp);
+      NS_GET16 (tclass, cp);
+      if (!__libc_res_nameinquery (tname, ttype, tclass, buf2, eom2))
+        return 0;
+    }
+  return 1;
+}
+libc_hidden_def (__libc_res_queriesmatch)

resolv/res_send.c

@@ -248,61 +248,6 @@ mask_ad_bit (struct resolv_context *ctx, void *buf)
     ((HEADER *) buf)->ad = 0;
 }
 
-/* int
- * res_queriesmatch(buf1, eom1, buf2, eom2)
- *	is there a 1:1 mapping of (name,type,class)
- *	in (buf1,eom1) and (buf2,eom2)?
- * returns:
- *	-1 : format error
- *	0  : not a 1:1 mapping
- *	>0 : is a 1:1 mapping
- * author:
- *	paul vixie, 29may94
- */
-int
-res_queriesmatch(const u_char *buf1, const u_char *eom1,
-		 const u_char *buf2, const u_char *eom2)
-{
-	if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
-		return (-1);
-
-	/*
-	 * Only header section present in replies to
-	 * dynamic update packets.
-	 */
-	if ((((HEADER *)buf1)->opcode == ns_o_update) &&
-	    (((HEADER *)buf2)->opcode == ns_o_update))
-		return (1);
-
-	/* Note that we initially do not convert QDCOUNT to the host byte
-	   order.  We can compare it with the second buffer's QDCOUNT
-	   value without doing this.  */
-	int qdcount = ((HEADER*)buf1)->qdcount;
-	if (qdcount != ((HEADER*)buf2)->qdcount)
-		return (0);
-
-	qdcount = htons (qdcount);
-	const u_char *cp = buf1 + HFIXEDSZ;
-
-	while (qdcount-- > 0) {
-		char tname[MAXDNAME+1];
-		int n, ttype, tclass;
-
-		n = __libc_dn_expand (buf1, eom1, cp, tname, sizeof tname);
-		if (n < 0)
-			return (-1);
-		cp += n;
-		if (cp + 2 * INT16SZ > eom1)
-			return (-1);
-		NS_GET16(ttype, cp);
-		NS_GET16(tclass, cp);
-		if (!__libc_res_nameinquery (tname, ttype, tclass, buf2, eom2))
-			return (0);
-	}
-	return (1);
-}
-libresolv_hidden_def (res_queriesmatch)
-
 int
 __res_context_send (struct resolv_context *ctx,
 		    const unsigned char *buf, int buflen,
@@ -1239,13 +1184,15 @@ send_dg(res_state statp,
 		int matching_query = 0; /* Default to no matching query.  */
 		if (!recvresp1
 		    && anhp->id == hp->id
-		    && res_queriesmatch (buf, buf + buflen,
+		    && __libc_res_queriesmatch (buf, buf + buflen,
-					 *thisansp, *thisansp + *thisanssizp))
+						*thisansp,
+						*thisansp + *thisanssizp))
 		  matching_query = 1;
 		if (!recvresp2
 		    && anhp->id == hp2->id
-		    && res_queriesmatch (buf2, buf2 + buflen2,
+		    && __libc_res_queriesmatch (buf2, buf2 + buflen2,
-					 *thisansp, *thisansp + *thisanssizp))
+						*thisansp,
+						*thisansp + *thisanssizp))
 		  matching_query = 2;
 		if (matching_query == 0)
 		  /* Spurious UDP packet.  Drop it and continue

resolv/resolv-deprecated.c

@@ -47,3 +47,10 @@ res_nameinquery (const char *name, int type, int class,
 {
   return __libc_res_nameinquery (name, type, class, buf, eom);
 }
+
+int
+res_queriesmatch (const unsigned char *buf1, const unsigned char *eom1,
+                  const unsigned char *buf2, const unsigned char *eom2)
+{
+  return __libc_res_queriesmatch (buf1, eom1, buf2, eom2);
+}