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Commit c2e8139c authored by Bryan Schumaker's avatar Bryan Schumaker Committed by Steve French
Browse files

NFS: Use kernel DNS resolver [ver #2] 



Use the kernel DNS resolver to translate hostnames to IP addresses.  Create a
new config option to choose between the legacy DNS resolver and the new
resolver.

Signed-off-by: default avatarBryan Schumaker <bjschuma@netapp.com>
Acked-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent 3694b91a

fs/nfs/Kconfig

+16 −0
Original line number Original line Diff line number Diff line
@@ -100,3 +100,19 @@ config NFS_FSCACHE 
	help

	help

	  Say Y here if you want NFS data to be cached locally on disc through

	  Say Y here if you want NFS data to be cached locally on disc through

	  the general filesystem cache manager

	  the general filesystem cache manager



config NFS_USE_LEGACY_DNS

	bool "Use the legacy NFS DNS resolver"

	depends on NFS_V4

	help

	  The kernel now provides a method for translating a host name into an

	  IP address.  Select Y here if you would rather use your own DNS

	  resolver script.



	  If unsure, say N



config NFS_USE_KERNEL_DNS

	bool

	depends on NFS_V4 && !NFS_USE_LEGACY_DNS

	select DNS_RESOLVER

	default y

fs/nfs/dns_resolve.c

+24 −0
Original line number Original line Diff line number Diff line
@@ -6,6 +6,29 @@ 
 * Resolves DNS hostnames into valid ip addresses

 * Resolves DNS hostnames into valid ip addresses

 */

 */





#ifdef CONFIG_NFS_USE_KERNEL_DNS



#include <linux/sunrpc/clnt.h>

#include <linux/dns_resolver.h>



ssize_t nfs_dns_resolve_name(char *name, size_t namelen,

		struct sockaddr *sa, size_t salen)

{

	ssize_t ret;

	char *ip_addr = NULL;

	int ip_len;



	ip_len = dns_query(NULL, name, namelen, NULL, &ip_addr, NULL);

	if (ip_len > 0)

		ret = rpc_pton(ip_addr, ip_len, sa, salen);

	else

		ret = -ESRCH;

	kfree(ip_addr);

	return ret;

}



#else



#include <linux/hash.h>

#include <linux/hash.h>

#include <linux/string.h>

#include <linux/string.h>

#include <linux/kmod.h>

#include <linux/kmod.h>
@@ -346,3 +369,4 @@ void nfs_dns_resolver_destroy(void) 
	nfs_cache_unregister(&nfs_dns_resolve);

	nfs_cache_unregister(&nfs_dns_resolve);

}

}





#endif

fs/nfs/dns_resolve.h

+12 −0
Original line number Original line Diff line number Diff line
@@ -6,8 +6,20 @@ 




#define NFS_DNS_HOSTNAME_MAXLEN	(128)

#define NFS_DNS_HOSTNAME_MAXLEN	(128)







#ifdef CONFIG_NFS_USE_KERNEL_DNS

static inline int nfs_dns_resolver_init(void)

{

	return 0;

}



static inline void nfs_dns_resolver_destroy(void)

{}

#else

extern int nfs_dns_resolver_init(void);

extern int nfs_dns_resolver_init(void);

extern void nfs_dns_resolver_destroy(void);

extern void nfs_dns_resolver_destroy(void);

#endif



extern ssize_t nfs_dns_resolve_name(char *name, size_t namelen,

extern ssize_t nfs_dns_resolve_name(char *name, size_t namelen,

		struct sockaddr *sa, size_t salen);

		struct sockaddr *sa, size_t salen);