From c2e8139c9f797baa46515af6d350c51823736cbb Mon Sep 17 00:00:00 2001 From: Bryan Schumaker <bjschuma@netapp.com> Date: Wed, 11 Aug 2010 09:37:53 +0100 Subject: 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: Bryan Schumaker <bjschuma@netapp.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com> --- fs/nfs/Kconfig | 16 ++++++++++++++++ fs/nfs/dns_resolve.c | 24 ++++++++++++++++++++++++ fs/nfs/dns_resolve.h | 12 ++++++++++++ 3 files changed, 52 insertions(+) (limited to 'fs/nfs') diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig index cc1bb33..c5bbdca 100644 --- a/fs/nfs/Kconfig +++ b/fs/nfs/Kconfig @@ -100,3 +100,19 @@ config NFS_FSCACHE help Say Y here if you want NFS data to be cached locally on disc through 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 diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c index 76fd235..dba50a5 100644 --- a/fs/nfs/dns_resolve.c +++ b/fs/nfs/dns_resolve.c @@ -6,6 +6,29 @@ * 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/string.h> #include <linux/kmod.h> @@ -346,3 +369,4 @@ void nfs_dns_resolver_destroy(void) nfs_cache_unregister(&nfs_dns_resolve); } +#endif diff --git a/fs/nfs/dns_resolve.h b/fs/nfs/dns_resolve.h index a3f0938..199bb55 100644 --- a/fs/nfs/dns_resolve.h +++ b/fs/nfs/dns_resolve.h @@ -6,8 +6,20 @@ #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 void nfs_dns_resolver_destroy(void); +#endif + extern ssize_t nfs_dns_resolve_name(char *name, size_t namelen, struct sockaddr *sa, size_t salen); -- cgit v1.1 From 3f43231230664c23f4a7513232171dcb6ce9f068 Mon Sep 17 00:00:00 2001 From: Steve French <sfrench@us.ibm.com> Date: Thu, 12 Aug 2010 18:16:45 +0000 Subject: [NFS] Set CONFIG_KEYS when CONFIG_NFS_USE_KERNEL_DNS is set Previous patch relied on DNS_RESOLVER setting CONFIG_KEYS but needs to be selected in NFS config when using the new DNS resolver Signed-off-by: Bryan Schumaker <bjschuma@netapp.com> CC: David Howells <dhowells@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com> --- fs/nfs/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/nfs') diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig index c5bbdca..26a510a 100644 --- a/fs/nfs/Kconfig +++ b/fs/nfs/Kconfig @@ -115,4 +115,5 @@ config NFS_USE_KERNEL_DNS bool depends on NFS_V4 && !NFS_USE_LEGACY_DNS select DNS_RESOLVER + select KEYS default y -- cgit v1.1