nss_dns: Remove RES_USE_INET6 handling

Message ID 87ef4ys1oj.fsf@oldenburg2.str.redhat.com
State New
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Series
  • nss_dns: Remove RES_USE_INET6 handling
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Commit Message

Florian Weimer May 16, 2019, 6:18 p.m.
Since commit 3f8b44be0a658266adff5ece1e4bc3ce097a5dbe ("resolv:
Remove support for RES_USE_INET6 and the inet6 option"),
res_use_inet6 () always evaluates to false.

2019-05-16  Florian Weimer  <fweimer@redhat.com>

	* resolv/nss_dns/dns-host.c (gethostbyname3_context): Do not
	perform IPv6 lookup.
	(_nss_dns_gethostbyname_r): Do not request IPv4 address mapping
	from gethostbyname3_context.

Comments

Florian Weimer May 17, 2019, 9:11 a.m. | #1
* Florian Weimer:

> Since commit 3f8b44be0a658266adff5ece1e4bc3ce097a5dbe ("resolv:

> Remove support for RES_USE_INET6 and the inet6 option"),

> res_use_inet6 () always evaluates to false.

>

> 2019-05-16  Florian Weimer  <fweimer@redhat.com>

>

> 	* resolv/nss_dns/dns-host.c (gethostbyname3_context): Do not

> 	perform IPv6 lookup.

> 	(_nss_dns_gethostbyname_r): Do not request IPv4 address mapping

> 	from gethostbyname3_context.


I forgot to update the ChangeLog entry after making further cleanups:

2019-05-17  Florian Weimer  <fweimer@redhat.com>

	* resolv/nss_dns/dns-host.c (gethostbyname3_context): Do not
	perform IPv6 lookup.  Adjust getanswer_r call.
	(_nss_dns_gethostbyname_r): Do not request IPv4 address mapping
	from gethostbyname3_context.
	(_nss_dns_gethostbyaddr2_r): Adjust getanswer_r call.
	(getanswer_r): Remove map argument.  Do not perform address
	mapping.

Florian

> diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c

> index 9c40051aff..40c23dfe00 100644

> --- a/resolv/nss_dns/dns-host.c

> +++ b/resolv/nss_dns/dns-host.c

> @@ -85,10 +85,6 @@

>  #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

> @@ -114,7 +110,7 @@ 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 gaih_getanswer (const querybuf *answer1, int anslen1,

>  				       const querybuf *answer2, int anslen2,

> @@ -182,7 +178,6 @@ 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;

>  

> @@ -244,31 +239,14 @@ gethostbyname3_context (struct resolv_context *ctx,

>        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;

> +      if (host_buffer.buf != orig_host_buffer)

> +	free (host_buffer.buf);

> +      return status;

>      }

>  

>    status = getanswer_r

>      (ctx, host_buffer.buf, n, name, type, result, buffer, buflen,

> -     errnop, h_errnop, map, ttlp, canonp);

> +     errnop, h_errnop, ttlp, canonp);

>    if (host_buffer.buf != orig_host_buffer)

>      free (host_buffer.buf);

>    return status;

> @@ -314,13 +292,8 @@ _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;

>  }

> @@ -547,7 +520,7 @@ _nss_dns_gethostbyaddr2_r (const void *addr, socklen_t len, int af,

>  

>    status = getanswer_r

>      (ctx, host_buffer.buf, n, qbuf, T_PTR, result, buffer, buflen,

> -     errnop, h_errnop, 0 /* XXX */, ttlp, NULL);

> +     errnop, h_errnop, ttlp, NULL);

>    if (host_buffer.buf != orig_host_buffer)

>      free (host_buffer.buf);

>    if (status != NSS_STATUS_SUCCESS)

> @@ -627,7 +600,7 @@ 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

>    {

> @@ -645,7 +618,6 @@ getanswer_r (struct resolv_context *ctx,

>    const char *tname;

>    int (*name_ok) (const char *);

>    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;

> @@ -870,9 +842,7 @@ 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++ ? */

> @@ -995,9 +965,6 @@ 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;

>      }

Patch

diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c
index 9c40051aff..40c23dfe00 100644
--- a/resolv/nss_dns/dns-host.c
+++ b/resolv/nss_dns/dns-host.c
@@ -85,10 +85,6 @@ 
 #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
@@ -114,7 +110,7 @@  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 gaih_getanswer (const querybuf *answer1, int anslen1,
 				       const querybuf *answer2, int anslen2,
@@ -182,7 +178,6 @@  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;
 
@@ -244,31 +239,14 @@  gethostbyname3_context (struct resolv_context *ctx,
       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;
+      if (host_buffer.buf != orig_host_buffer)
+	free (host_buffer.buf);
+      return status;
     }
 
   status = getanswer_r
     (ctx, host_buffer.buf, n, name, type, result, buffer, buflen,
-     errnop, h_errnop, map, ttlp, canonp);
+     errnop, h_errnop, ttlp, canonp);
   if (host_buffer.buf != orig_host_buffer)
     free (host_buffer.buf);
   return status;
@@ -314,13 +292,8 @@  _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;
 }
@@ -547,7 +520,7 @@  _nss_dns_gethostbyaddr2_r (const void *addr, socklen_t len, int af,
 
   status = getanswer_r
     (ctx, host_buffer.buf, n, qbuf, T_PTR, result, buffer, buflen,
-     errnop, h_errnop, 0 /* XXX */, ttlp, NULL);
+     errnop, h_errnop, ttlp, NULL);
   if (host_buffer.buf != orig_host_buffer)
     free (host_buffer.buf);
   if (status != NSS_STATUS_SUCCESS)
@@ -627,7 +600,7 @@  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
   {
@@ -645,7 +618,6 @@  getanswer_r (struct resolv_context *ctx,
   const char *tname;
   int (*name_ok) (const char *);
   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;
@@ -870,9 +842,7 @@  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++ ? */
@@ -995,9 +965,6 @@  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;
     }