[PATCH 09/13] nss_dns: Remove remnants of IPv6 address mapping
Siddhesh Poyarekar
siddhesh@gotplt.org
Mon Aug 22 22:05:17 GMT 2022
On 2022-08-10 05:30, Florian Weimer via Libc-alpha wrote:
> res_use_inet6 always returns false since commit 3f8b44be0a658266adff5
> ("resolv: Remove support for RES_USE_INET6 and the inet6 option").
> ---
> resolv/README | 3 --
> resolv/mapv4v6addr.h | 69 --------------------------------
> resolv/mapv4v6hostent.h | 84 ---------------------------------------
> resolv/nss_dns/dns-host.c | 54 +++++--------------------
> 4 files changed, 9 insertions(+), 201 deletions(-)
> delete mode 100644 resolv/mapv4v6addr.h
> delete mode 100644 resolv/mapv4v6hostent.h
LGTM.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
>
> diff --git a/resolv/README b/resolv/README
> index 514e9bb617..2146bc3b27 100644
> --- a/resolv/README
> +++ b/resolv/README
> @@ -146,6 +146,3 @@ res_libc.c is home-brewn, although parts of it are taken from res_data.c.
>
> res_hconf.c and res_hconf.h were contributed by David Mosberger, and
> do not come from BIND.
> -
> -The files gethnamaddr.c, mapv4v6addr.h and mapv4v6hostent.h are
> -leftovers from BIND 4.9.7.
> diff --git a/resolv/mapv4v6addr.h b/resolv/mapv4v6addr.h
> deleted file mode 100644
> index 7f85f7d5e3..0000000000
> --- a/resolv/mapv4v6addr.h
> +++ /dev/null
> @@ -1,69 +0,0 @@
> -/*
> - * ++Copyright++ 1985, 1988, 1993
> - * -
> - * Copyright (c) 1985, 1988, 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.
> - * -
> - * --Copyright--
> - */
> -
> -#include <string.h>
> -#include <arpa/nameser.h>
> -
> -static void
> -map_v4v6_address (const char *src, char *dst)
> -{
> - u_char *p = (u_char *) dst;
> - int i;
> -
> - /* Move the IPv4 part to the right position. */
> - memcpy (dst + 12, src, INADDRSZ);
> -
> - /* Mark this ipv6 addr as a mapped ipv4. */
> - for (i = 0; i < 10; i++)
> - *p++ = 0x00;
> - *p++ = 0xff;
> - *p = 0xff;
> -}
> diff --git a/resolv/mapv4v6hostent.h b/resolv/mapv4v6hostent.h
> deleted file mode 100644
> index c11038adf3..0000000000
> --- a/resolv/mapv4v6hostent.h
> +++ /dev/null
> @@ -1,84 +0,0 @@
> -/*
> - * ++Copyright++ 1985, 1988, 1993
> - * -
> - * Copyright (c) 1985, 1988, 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.
> - * -
> - * --Copyright--
> - */
> -
> -#include <arpa/nameser.h>
> -#include <sys/socket.h>
> -
> -typedef union {
> - int32_t al;
> - char ac;
> -} align;
> -
> -static int
> -map_v4v6_hostent (struct hostent *hp, char **bpp, int *lenp)
> -{
> - char **ap;
> -
> - if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
> - return 0;
> - hp->h_addrtype = AF_INET6;
> - hp->h_length = IN6ADDRSZ;
> - for (ap = hp->h_addr_list; *ap; ap++)
> - {
> - int i = sizeof (align) - ((u_long) *bpp % sizeof (align));
> -
> - if (*lenp < (i + IN6ADDRSZ))
> - /* Out of memory. */
> - return 1;
> - *bpp += i;
> - *lenp -= i;
> - map_v4v6_address (*ap, *bpp);
> - *ap = *bpp;
> - *bpp += IN6ADDRSZ;
> - *lenp -= IN6ADDRSZ;
> - }
> - return 0;
> -}
> diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c
> index cd26399b7e..8e38583e15 100644
> --- a/resolv/nss_dns/dns-host.c
> +++ b/resolv/nss_dns/dns-host.c
> @@ -87,10 +87,6 @@
> #include <resolv/resolv-internal.h>
> #include <resolv/resolv_context.h>
>
> -/* Get implementations of some internal functions. */
> -#include <resolv/mapv4v6addr.h>
> -#include <resolv/mapv4v6hostent.h>
> -
> #define RESOLVSORT
>
> #if PACKETSZ > 65536
> @@ -116,7 +112,7 @@ static enum nss_status getanswer_r (struct resolv_context *ctx,
> const char *qname, int qtype,
> struct hostent *result, char *buffer,
> size_t buflen, int *errnop, int *h_errnop,
> - int map, int32_t *ttlp, char **canonp);
> + int32_t *ttlp, char **canonp);
> static enum nss_status getanswer_ptr (unsigned char *packet, size_t packetlen,
> struct alloc_buffer *abuf,
> char **hnamep, int *errnop,
> @@ -197,7 +193,6 @@ gethostbyname3_context (struct resolv_context *ctx,
> char tmp[NS_MAXDNAME];
> int size, type, n;
> const char *cp;
> - int map = 0;
> int olderr = errno;
> enum nss_status status;
>
> @@ -258,32 +253,12 @@ gethostbyname3_context (struct resolv_context *ctx,
> *errnop = EAGAIN;
> else
> __set_errno (olderr);
> -
> - /* If we are looking for an IPv6 address and mapping is enabled
> - by having the RES_USE_INET6 bit in _res.options set, we try
> - another lookup. */
> - if (af == AF_INET6 && res_use_inet6 ())
> - n = __res_context_search (ctx, name, C_IN, T_A, host_buffer.buf->buf,
> - host_buffer.buf != orig_host_buffer
> - ? MAXPACKET : 1024, &host_buffer.ptr,
> - NULL, NULL, NULL, NULL);
> -
> - if (n < 0)
> - {
> - if (host_buffer.buf != orig_host_buffer)
> - free (host_buffer.buf);
> - return status;
> - }
> -
> - map = 1;
> -
> - result->h_addrtype = AF_INET;
> - result->h_length = INADDRSZ;
> }
> + else
> + status = getanswer_r
> + (ctx, host_buffer.buf, n, name, type, result, buffer, buflen,
> + errnop, h_errnop, ttlp, canonp);
>
> - status = getanswer_r
> - (ctx, host_buffer.buf, n, name, type, result, buffer, buflen,
> - errnop, h_errnop, map, ttlp, canonp);
> if (host_buffer.buf != orig_host_buffer)
> free (host_buffer.buf);
> return status;
> @@ -329,13 +304,8 @@ _nss_dns_gethostbyname_r (const char *name, struct hostent *result,
> *h_errnop = NETDB_INTERNAL;
> return NSS_STATUS_UNAVAIL;
> }
> - status = NSS_STATUS_NOTFOUND;
> - if (res_use_inet6 ())
> - status = gethostbyname3_context (ctx, name, AF_INET6, result, buffer,
> - buflen, errnop, h_errnop, NULL, NULL);
> - if (status == NSS_STATUS_NOTFOUND)
> - status = gethostbyname3_context (ctx, name, AF_INET, result, buffer,
> - buflen, errnop, h_errnop, NULL, NULL);
> + status = gethostbyname3_context (ctx, name, AF_INET, result, buffer,
> + buflen, errnop, h_errnop, NULL, NULL);
> __resolv_context_put (ctx);
> return status;
> }
> @@ -648,7 +618,7 @@ static enum nss_status
> getanswer_r (struct resolv_context *ctx,
> const querybuf *answer, int anslen, const char *qname, int qtype,
> struct hostent *result, char *buffer, size_t buflen,
> - int *errnop, int *h_errnop, int map, int32_t *ttlp, char **canonp)
> + int *errnop, int *h_errnop, int32_t *ttlp, char **canonp)
> {
> struct host_data
> {
> @@ -664,7 +634,6 @@ getanswer_r (struct resolv_context *ctx,
> char *bp, **ap, **hap;
> char tbuf[MAXDNAME];
> u_char packtmp[NS_MAXCDNAME];
> - int have_to_map = 0;
> uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct host_data);
> buffer += pad;
> buflen = buflen > pad ? buflen - pad : 0;
> @@ -845,9 +814,7 @@ getanswer_r (struct resolv_context *ctx,
> continue;
> }
>
> - if (type == T_A && qtype == T_AAAA && map)
> - have_to_map = 1;
> - else if (__glibc_unlikely (type != qtype))
> + if (__glibc_unlikely (type != qtype))
> {
> cp += n;
> continue; /* XXX - had_error++ ? */
> @@ -944,9 +911,6 @@ getanswer_r (struct resolv_context *ctx,
> linebuflen -= n;
> }
>
> - if (have_to_map)
> - if (map_v4v6_hostent (result, &bp, &linebuflen))
> - goto too_small;
> *h_errnop = NETDB_SUCCESS;
> return NSS_STATUS_SUCCESS;
> }
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