Re: [PATCH 23/30] resolv: Move res_queriesmatch to its own file and into libc

[Carlos O'Donell via Libc-alpha <libc-alpha@sourceware.org>]

On 7/8/21 11:06 AM, Florian Weimer via Libc-alpha wrote:
> And reformat it to GNU style.
> 
> The treatment of this function matches res_nameinquery, for the
> reasons stated there.

OK for glibc 2.34.

Tested without regression on x86_64 and i686.

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

> ---
>  include/resolv.h           |   3 +-
>  resolv/Makefile            |   1 +
>  resolv/Versions            |   1 +
>  resolv/res_queriesmatch.c  | 129 +++++++++++++++++++++++++++++++++++++
>  resolv/res_send.c          |  65 ++-----------------
>  resolv/resolv-deprecated.c |   7 ++
>  6 files changed, 146 insertions(+), 60 deletions(-)
>  create mode 100644 resolv/res_queriesmatch.c
> 
> diff --git a/include/resolv.h b/include/resolv.h
> index 4d328fe914..3590b6f496 100644
> --- a/include/resolv.h
> +++ b/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)

OK.

>  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)

OK.

>  
>  # endif /* _RESOLV_H_ && !_ISOMAC */
>  #endif
> diff --git a/resolv/Makefile b/resolv/Makefile
> index c4c59dcac0..83ba39cb52 100644
> --- a/resolv/Makefile
> +++ b/resolv/Makefile
> @@ -53,6 +53,7 @@ routines := \
>    res_init \
>    res_libc \
>    res_nameinquery \
> +  res_queriesmatch \

OK.

>    res_randomid \
>    resolv_conf \
>    resolv_context \
> diff --git a/resolv/zs b/resolv/Versions
> index f3482793dd..5bbda96230 100644
> --- a/resolv/Versions
> +++ b/resolv/Versions
> @@ -77,6 +77,7 @@ libc {
>      __libc_res_dnok;
>      __libc_res_hnok;
>      __libc_res_nameinquery;
> +    __libc_res_queriesmatch;

OK.

>      __ns_name_compress;
>      __ns_name_ntop;
>      __ns_name_pack;
> diff --git a/resolv/res_queriesmatch.c b/resolv/res_queriesmatch.c
> new file mode 100644
> index 0000000000..4b56d33193
> --- /dev/null
> +++ b/resolv/res_queriesmatch.c
> @@ -0,0 +1,129 @@
> +/* Check if two DNS packets contain the same query.

OK.

> +   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)

OK.

> +{
> +  if (eom1 - buf1 < HFIXEDSZ || eom2 - buf2 < HFIXEDSZ)
> +    return -1;

OK. Rewrite. Looks correct.

> +
> +  /* 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;

OK.

> +
> +  /* 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;

OK.

> +
> +  qdcount = htons (qdcount);
> +  const unsigned char *cp = buf1 + HFIXEDSZ;

OK.

> +
> +  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;

OK. Rewrite and expand. Looks correct.

> +      NS_GET16 (ttype, cp);
> +      NS_GET16 (tclass, cp);
> +      if (!__libc_res_nameinquery (tname, ttype, tclass, buf2, eom2))
> +        return 0;

OK.

> +    }
> +  return 1;
> +}
> +libc_hidden_def (__libc_res_queriesmatch)
> diff --git a/resolv/res_send.c b/resolv/res_send.c
> index a5a33e6f3b..b502ef5132 100644
> --- a/resolv/res_send.c
> +++ b/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)
> -

OK. Remove.

>  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,
> -					 *thisansp, *thisansp + *thisanssizp))
> +		    && __libc_res_queriesmatch (buf, buf + buflen,
> +						*thisansp,
> +						*thisansp + *thisanssizp))

OK.

>  		  matching_query = 1;
>  		if (!recvresp2
>  		    && anhp->id == hp2->id
> -		    && res_queriesmatch (buf2, buf2 + buflen2,
> -					 *thisansp, *thisansp + *thisanssizp))
> +		    && __libc_res_queriesmatch (buf2, buf2 + buflen2,
> +						*thisansp,
> +						*thisansp + *thisanssizp))

OK.

>  		  matching_query = 2;
>  		if (matching_query == 0)
>  		  /* Spurious UDP packet.  Drop it and continue
> diff --git a/resolv/resolv-deprecated.c b/resolv/resolv-deprecated.c
> index 0fe9e4fda6..a2953db963 100644
> --- a/resolv/resolv-deprecated.c
> +++ b/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);

OK. Add forwarder.

> +}
> 


-- 
Cheers,
Carlos.