From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:20129 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756202Ab0HILvb (ORCPT ); Mon, 9 Aug 2010 07:51:31 -0400 From: David Howells Subject: [PATCH] NFS: Use kernel DNS resolver To: torvalds@osdl.org, akpm@linux-foundation.org Cc: linux-nfs@vger.kernel.org, smfrench@gmail.com, linux-kernel@vger.kernel.org, Bryan Schumaker , Trond Myklebust , David Howells Date: Mon, 09 Aug 2010 12:50:46 +0100 Message-ID: <20100809115046.1461.7584.stgit@warthog.procyon.org.uk> Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 From: Bryan Schumaker 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 Acked-by: Trond Myklebust Signed-off-by: David Howells --- fs/nfs/Kconfig | 16 ++++++++++++++++ fs/nfs/dns_resolve.c | 24 ++++++++++++++++++++++++ fs/nfs/dns_resolve.h | 12 ++++++++++++ 3 files changed, 52 insertions(+), 0 deletions(-) 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 +#include + +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 #include #include @@ -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);