Re: [PATCH 5/8] SUNRPC: Use new rpcb_v4_register() interface in svc_register()

["J. Bruce Fields" <bfields@fieldses.org>]

On Mon, Jun 30, 2008 at 06:46:01PM -0400, Chuck Lever wrote:
> In order to advertise NFS-related services on IPv6 interfaces via
> rpcbind, the kernel RPC server implementation must use
> rpcb_v4_register() instead of rpcb_register().
> 
> Legacy support (register using portmapper/rpcbindv2) is still available.
> The new rpcbind version is not used unless enabled via a CONFIG option.

So a kernel built with CONFIG_SUNRPC_REGISTER_V4 will no longer support
old userspace?

--b.

> 
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
> 
>  net/sunrpc/svc.c |   73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 73 insertions(+), 0 deletions(-)
> 
> 
> diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
> index c31a1e4..13cca03 100644
> --- a/net/sunrpc/svc.c
> +++ b/net/sunrpc/svc.c
> @@ -749,6 +749,74 @@ svc_exit_thread(struct svc_rqst *rqstp)
>  }
>  EXPORT_SYMBOL(svc_exit_thread);
>  
> +#ifdef CONFIG_SUNRPC_REGISTER_V4
> +/*
> + * Registering kernel RPC services with rpcbind version 2 will work
> + * over either IPv4 or IPv6, since the Linux kernel always registers
> + * services for the "any" address.
> + *
> + * However, the local rpcbind daemon listens on either only AF_INET
> + * or AF_INET6 (never both).  When it listens on AF_INET6, an rpcbind
> + * version 2 registration will result in registering the service at
> + * IN6ADDR_ANY, even if the RPC service being registered is not
> + * IPv6-enabled.
> + *
> + * Rpcbind version 4 allows us to be a little more specific.  Kernel
> + * RPC services that don't yet support AF_INET6 can register
> + * themselves as IPv4-only with the local rpcbind daemon, even if the
> + * daemon is listening only on AF_INET6.
> + *
> + * And, registering IPv6-enabled kernel RPC services via AF_INET6
> + * verifies that the local user space rpcbind daemon is properly
> + * configured to support remote AF_INET6 rpcbind requests.
> + *
> + * An AF_INET6 registration request will fail if the local rpcbind
> + * daemon is not set up to listen on AF_INET6.  Likewise, we fail
> + * AF_INET6 registration requests if svc_register() is configured to
> + * support only rpcbind version 2.
> + */
> +static int __svc_register(const u32 program, const u32 version,
> +			  const sa_family_t family,
> +			  const unsigned short protocol,
> +			  const unsigned short port)
> +{
> +	struct sockaddr_in sin = {
> +		.sin_family		= AF_INET,
> +		.sin_addr.s_addr	= htonl(INADDR_ANY),
> +		.sin_port		= htons(port),
> +	};
> +	struct sockaddr_in6 sin6 = {
> +		.sin6_family		= AF_INET6,
> +		.sin6_addr		= IN6ADDR_ANY_INIT,
> +		.sin6_port		= htons(port),
> +	};
> +	struct sockaddr *sap;
> +	char *netid;
> +	int error, result;
> +
> +	switch (family) {
> +	case AF_INET:
> +		sap = (struct sockaddr *)&sin;
> +		netid = RPCBIND_NETID_TCP;
> +		if (protocol == IPPROTO_UDP)
> +			netid = RPCBIND_NETID_UDP;
> +		break;
> +	case AF_INET6:
> +		sap = (struct sockaddr *)&sin6;
> +		netid = RPCBIND_NETID_TCP6;
> +		if (protocol == IPPROTO_UDP)
> +			netid = RPCBIND_NETID_UDP6;
> +		break;
> +	default:
> +		return -EAFNOSUPPORT;
> +	}
> +
> +	error = rpcb_v4_register(program, version, sap, netid, &result);
> +	if (!result)
> +		error = -EACCES;
> +	return error;
> +}
> +#else
>  static int __svc_register(const u32 program, const u32 version,
>  			  sa_family_t family,
>  			  const unsigned short protocol,
> @@ -756,11 +824,15 @@ static int __svc_register(const u32 program, const u32 version,
>  {
>  	int error, result;
>  
> +	if (family != AF_INET)
> +		return -EAFNOSUPPORT;
> +
>  	error = rpcb_register(program, version, protocol, port, &result);
>  	if (!result)
>  		error = -EACCES;
>  	return error;
>  }
> +#endif
>  
>  /**
>   * svc_register - register an RPC service with the local portmapper
> @@ -768,6 +840,7 @@ static int __svc_register(const u32 program, const u32 version,
>   * @protocol: transport protocol number to advertise
>   * @port: port to advertise
>   *
> + * Service is registered for any address in serv's address family
>   */
>  int svc_register(const struct svc_serv *serv, const unsigned short protocol,
>  		 const unsigned short port)
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html