[deliverable/linux.git] / fs / nfs / callback.c

/*
 * linux/fs/nfs/callback.c
 *
 * Copyright (C) 2004 Trond Myklebust
 *
 * NFSv4 callback handling
 */

#include <linux/completion.h>
#include <linux/ip.h>
#include <linux/module.h>
#include <linux/smp_lock.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/nfs_fs.h>
#include <linux/mutex.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/sunrpc/svcauth_gss.h>

#include <net/inet_sock.h>

#include "nfs4_fs.h"
#include "callback.h"
#include "internal.h"

#define NFSDBG_FACILITY NFSDBG_CALLBACK

struct nfs_callback_data {
	unsigned int users;
	struct svc_rqst *rqst;
	struct task_struct *task;
};

static struct nfs_callback_data nfs_callback_info;
static DEFINE_MUTEX(nfs_callback_mutex);
static struct svc_program nfs4_callback_program;

unsigned int nfs_callback_set_tcpport;
unsigned short nfs_callback_tcpport;
static const int nfs_set_port_min = 0;
static const int nfs_set_port_max = 65535;

/*
 * If the kernel has IPv6 support available, always listen for
 * both AF_INET and AF_INET6 requests.
 */
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
static const sa_family_t	nfs_callback_family = AF_INET6;
#else
static const sa_family_t	nfs_callback_family = AF_INET;
#endif

static int param_set_port(const char *val, struct kernel_param *kp)
{
	char *endp;
	int num = simple_strtol(val, &endp, 0);
	if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max)
		return -EINVAL;
	*((int *)kp->arg) = num;
	return 0;
}

module_param_call(callback_tcpport, param_set_port, param_get_int,
		 &nfs_callback_set_tcpport, 0644);

/*
 * This is the callback kernel thread.
 */
static int
nfs_callback_svc(void *vrqstp)
{
	int err, preverr = 0;
	struct svc_rqst *rqstp = vrqstp;

	set_freezable();

	/*
	 * FIXME: do we really need to run this under the BKL? If so, please
	 * add a comment about what it's intended to protect.
	 */
	lock_kernel();
	while (!kthread_should_stop()) {
		/*
		 * Listen for a request on the socket
		 */
		err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
		if (err == -EAGAIN || err == -EINTR) {
			preverr = err;
			continue;
		}
		if (err < 0) {
			if (err != preverr) {
				printk(KERN_WARNING "%s: unexpected error "
					"from svc_recv (%d)\n", __func__, err);
				preverr = err;
			}
			schedule_timeout_uninterruptible(HZ);
			continue;
		}
		preverr = err;
		svc_process(rqstp);
	}
	unlock_kernel();
	return 0;
}

/*
 * Bring up the callback thread if it is not already up.
 */
int nfs_callback_up(void)
{
	struct svc_serv *serv = NULL;
	int ret = 0;

	mutex_lock(&nfs_callback_mutex);
	if (nfs_callback_info.users++ || nfs_callback_info.task != NULL)
		goto out;
	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE,
				nfs_callback_family, NULL);
	ret = -ENOMEM;
	if (!serv)
		goto out_err;

	ret = svc_create_xprt(serv, "tcp", nfs_callback_set_tcpport,
			      SVC_SOCK_ANONYMOUS);
	if (ret <= 0)
		goto out_err;
	nfs_callback_tcpport = ret;
	dprintk("NFS: Callback listener port = %u (af %u)\n",
			nfs_callback_tcpport, nfs_callback_family);

	nfs_callback_info.rqst = svc_prepare_thread(serv, &serv->sv_pools[0]);
	if (IS_ERR(nfs_callback_info.rqst)) {
		ret = PTR_ERR(nfs_callback_info.rqst);
		nfs_callback_info.rqst = NULL;
		goto out_err;
	}

	svc_sock_update_bufs(serv);

	nfs_callback_info.task = kthread_run(nfs_callback_svc,
					     nfs_callback_info.rqst,
					     "nfsv4-svc");
	if (IS_ERR(nfs_callback_info.task)) {
		ret = PTR_ERR(nfs_callback_info.task);
		svc_exit_thread(nfs_callback_info.rqst);
		nfs_callback_info.rqst = NULL;
		nfs_callback_info.task = NULL;
		goto out_err;
	}
out:
	/*
	 * svc_create creates the svc_serv with sv_nrthreads == 1, and then
	 * svc_prepare_thread increments that. So we need to call svc_destroy
	 * on both success and failure so that the refcount is 1 when the
	 * thread exits.
	 */
	if (serv)
		svc_destroy(serv);
	mutex_unlock(&nfs_callback_mutex);
	return ret;
out_err:
	dprintk("NFS: Couldn't create callback socket or server thread; "
		"err = %d\n", ret);
	nfs_callback_info.users--;
	goto out;
}

/*
 * Kill the callback thread if it's no longer being used.
 */
void nfs_callback_down(void)
{
	mutex_lock(&nfs_callback_mutex);
	nfs_callback_info.users--;
	if (nfs_callback_info.users == 0 && nfs_callback_info.task != NULL) {
		kthread_stop(nfs_callback_info.task);
		svc_exit_thread(nfs_callback_info.rqst);
		nfs_callback_info.rqst = NULL;
		nfs_callback_info.task = NULL;
	}
	mutex_unlock(&nfs_callback_mutex);
}

static int check_gss_callback_principal(struct nfs_client *clp,
					struct svc_rqst *rqstp)
{
	struct rpc_clnt *r = clp->cl_rpcclient;
	char *p = svc_gss_principal(rqstp);

	/*
	 * It might just be a normal user principal, in which case
	 * userspace won't bother to tell us the name at all.
	 */
	if (p == NULL)
		return SVC_DENIED;

	/* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */

	if (memcmp(p, "nfs@", 4) != 0)
		return SVC_DENIED;
	p += 4;
	if (strcmp(p, r->cl_server) != 0)
		return SVC_DENIED;
	return SVC_OK;
}

static int nfs_callback_authenticate(struct svc_rqst *rqstp)
{
	struct nfs_client *clp;
	RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
	int ret = SVC_OK;

	/* Don't talk to strangers */
	clp = nfs_find_client(svc_addr(rqstp), 4);
	if (clp == NULL)
		return SVC_DROP;

	dprintk("%s: %s NFSv4 callback!\n", __func__,
			svc_print_addr(rqstp, buf, sizeof(buf)));

	switch (rqstp->rq_authop->flavour) {
		case RPC_AUTH_NULL:
			if (rqstp->rq_proc != CB_NULL)
				ret = SVC_DENIED;
			break;
		case RPC_AUTH_UNIX:
			break;
		case RPC_AUTH_GSS:
			ret = check_gss_callback_principal(clp, rqstp);
			break;
		default:
			ret = SVC_DENIED;
	}
	nfs_put_client(clp);
	return ret;
}

/*
 * Define NFS4 callback program
 */
static struct svc_version *nfs4_callback_version[] = {
	[1] = &nfs4_callback_version1,
};

static struct svc_stat nfs4_callback_stats;

static struct svc_program nfs4_callback_program = {
	.pg_prog = NFS4_CALLBACK,			/* RPC service number */
	.pg_nvers = ARRAY_SIZE(nfs4_callback_version),	/* Number of entries */
	.pg_vers = nfs4_callback_version,		/* version table */
	.pg_name = "NFSv4 callback",			/* service name */
	.pg_class = "nfs",				/* authentication class */
	.pg_stats = &nfs4_callback_stats,
	.pg_authenticate = nfs_callback_authenticate,
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/nfs/callback.c
	3	*
	4	* Copyright (C) 2004 Trond Myklebust
	5	*
	6	* NFSv4 callback handling
	7	*/
	8
1da177e4 LT	9	#include <linux/completion.h>
	10	#include <linux/ip.h>
	11	#include <linux/module.h>
	12	#include <linux/smp_lock.h>
	13	#include <linux/sunrpc/svc.h>
	14	#include <linux/sunrpc/svcsock.h>
	15	#include <linux/nfs_fs.h>
353ab6e9	16	#include <linux/mutex.h>
83144186	17	#include <linux/freezer.h>
a277e33c	18	#include <linux/kthread.h>
945b34a7	19	#include <linux/sunrpc/svcauth_gss.h>
14c85021 ACM	20
	21	#include <net/inet_sock.h>
	22
4ce79717	23	#include "nfs4_fs.h"
1da177e4	24	#include "callback.h"
24c8dbbb	25	#include "internal.h"
1da177e4 LT	26
	27	#define NFSDBG_FACILITY NFSDBG_CALLBACK
	28
	29	struct nfs_callback_data {
	30	unsigned int users;
5afc597c	31	struct svc_rqst *rqst;
a277e33c	32	struct task_struct *task;
1da177e4 LT	33	};
	34
	35	static struct nfs_callback_data nfs_callback_info;
353ab6e9	36	static DEFINE_MUTEX(nfs_callback_mutex);
1da177e4 LT	37	static struct svc_program nfs4_callback_program;
1da177e4 LT	38
a72b4422	39	unsigned int nfs_callback_set_tcpport;
1da177e4	40	unsigned short nfs_callback_tcpport;
7d4e2747 DH	41	static const int nfs_set_port_min = 0;
	42	static const int nfs_set_port_max = 65535;
	43
18de9735 CL	44	/*
	45	* If the kernel has IPv6 support available, always listen for
	46	* both AF_INET and AF_INET6 requests.
	47	*/
	48	#if defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE)
	49	static const sa_family_t nfs_callback_family = AF_INET6;
	50	#else
	51	static const sa_family_t nfs_callback_family = AF_INET;
	52	#endif
	53
7d4e2747 DH	54	static int param_set_port(const char val, struct kernel_param kp)
	55	{
	56	char *endp;
	57	int num = simple_strtol(val, &endp, 0);
	58	if (endp == val \|\| *endp \|\| num < nfs_set_port_min \|\| num > nfs_set_port_max)
	59	return -EINVAL;
	60	((int )kp->arg) = num;
	61	return 0;
	62	}
	63
	64	module_param_call(callback_tcpport, param_set_port, param_get_int,
	65	&nfs_callback_set_tcpport, 0644);
1da177e4 LT	66
	67	/*
	68	* This is the callback kernel thread.
	69	*/
a277e33c JL	70	static int
a277e33c JL	71	nfs_callback_svc(void *vrqstp)
1da177e4	72	{
06e02d66	73	int err, preverr = 0;
a277e33c	74	struct svc_rqst *rqstp = vrqstp;
1da177e4	75
83144186	76	set_freezable();
1da177e4	77
a277e33c JL	78	/*
	79	* FIXME: do we really need to run this under the BKL? If so, please
	80	* add a comment about what it's intended to protect.
	81	*/
	82	lock_kernel();
	83	while (!kthread_should_stop()) {
1da177e4 LT	84	/*
	85	* Listen for a request on the socket
	86	*/
6fb2b47f	87	err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
06e02d66 JL	88	if (err == -EAGAIN \|\| err == -EINTR) {
06e02d66 JL	89	preverr = err;
1da177e4	90	continue;
06e02d66	91	}
1da177e4	92	if (err < 0) {
06e02d66 JL	93	if (err != preverr) {
	94	printk(KERN_WARNING "%s: unexpected error "
	95	"from svc_recv (%d)\n", __func__, err);
	96	preverr = err;
	97	}
	98	schedule_timeout_uninterruptible(HZ);
	99	continue;
1da177e4	100	}
06e02d66	101	preverr = err;
6fb2b47f	102	svc_process(rqstp);
1da177e4	103	}
1da177e4	104	unlock_kernel();
a277e33c	105	return 0;
1da177e4 LT	106	}
	107
	108	/*
5afc597c	109	* Bring up the callback thread if it is not already up.
1da177e4 LT	110	*/
	111	int nfs_callback_up(void)
	112	{
8e60029f	113	struct svc_serv *serv = NULL;
1da177e4 LT	114	int ret = 0;
1da177e4 LT	115
353ab6e9	116	mutex_lock(&nfs_callback_mutex);
a277e33c	117	if (nfs_callback_info.users++ \|\| nfs_callback_info.task != NULL)
1da177e4	118	goto out;
e851db5b	119	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE,
18de9735	120	nfs_callback_family, NULL);
1da177e4 LT	121	ret = -ENOMEM;
	122	if (!serv)
	123	goto out_err;
482fb94e	124
d7c9f1ed TT	125	ret = svc_create_xprt(serv, "tcp", nfs_callback_set_tcpport,
d7c9f1ed TT	126	SVC_SOCK_ANONYMOUS);
482fb94e	127	if (ret <= 0)
8e60029f	128	goto out_err;
482fb94e	129	nfs_callback_tcpport = ret;
18de9735 CL	130	dprintk("NFS: Callback listener port = %u (af %u)\n",
18de9735 CL	131	nfs_callback_tcpport, nfs_callback_family);
482fb94e	132
5afc597c JL	133	nfs_callback_info.rqst = svc_prepare_thread(serv, &serv->sv_pools[0]);
	134	if (IS_ERR(nfs_callback_info.rqst)) {
	135	ret = PTR_ERR(nfs_callback_info.rqst);
	136	nfs_callback_info.rqst = NULL;
8e60029f	137	goto out_err;
a277e33c JL	138	}
	139
	140	svc_sock_update_bufs(serv);
a277e33c	141
5afc597c JL	142	nfs_callback_info.task = kthread_run(nfs_callback_svc,
5afc597c JL	143	nfs_callback_info.rqst,
a277e33c JL	144	"nfsv4-svc");
	145	if (IS_ERR(nfs_callback_info.task)) {
	146	ret = PTR_ERR(nfs_callback_info.task);
5afc597c JL	147	svc_exit_thread(nfs_callback_info.rqst);
5afc597c JL	148	nfs_callback_info.rqst = NULL;
a277e33c	149	nfs_callback_info.task = NULL;
a277e33c JL	150	goto out_err;
a277e33c JL	151	}
1da177e4	152	out:
8e60029f JL	153	/*
8e60029f JL	154	* svc_create creates the svc_serv with sv_nrthreads == 1, and then
a277e33c	155	* svc_prepare_thread increments that. So we need to call svc_destroy
8e60029f JL	156	* on both success and failure so that the refcount is 1 when the
	157	* thread exits.
	158	*/
	159	if (serv)
	160	svc_destroy(serv);
353ab6e9	161	mutex_unlock(&nfs_callback_mutex);
1da177e4	162	return ret;
8e60029f	163	out_err:
18de9735 CL	164	dprintk("NFS: Couldn't create callback socket or server thread; "
18de9735 CL	165	"err = %d\n", ret);
1da177e4 LT	166	nfs_callback_info.users--;
	167	goto out;
	168	}
	169
	170	/*
5afc597c	171	* Kill the callback thread if it's no longer being used.
1da177e4	172	*/
5ae1fbce	173	void nfs_callback_down(void)
1da177e4	174	{
353ab6e9	175	mutex_lock(&nfs_callback_mutex);
1dd761e9	176	nfs_callback_info.users--;
5afc597c	177	if (nfs_callback_info.users == 0 && nfs_callback_info.task != NULL) {
a277e33c	178	kthread_stop(nfs_callback_info.task);
5afc597c JL	179	svc_exit_thread(nfs_callback_info.rqst);
	180	nfs_callback_info.rqst = NULL;
	181	nfs_callback_info.task = NULL;
	182	}
353ab6e9	183	mutex_unlock(&nfs_callback_mutex);
1da177e4 LT	184	}
1da177e4 LT	185
945b34a7 OK	186	static int check_gss_callback_principal(struct nfs_client *clp,
	187	struct svc_rqst *rqstp)
	188	{
	189	struct rpc_clnt *r = clp->cl_rpcclient;
	190	char *p = svc_gss_principal(rqstp);
	191
	192	/*
	193	* It might just be a normal user principal, in which case
	194	* userspace won't bother to tell us the name at all.
	195	*/
	196	if (p == NULL)
	197	return SVC_DENIED;
	198
	199	/* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
	200
	201	if (memcmp(p, "nfs@", 4) != 0)
	202	return SVC_DENIED;
	203	p += 4;
	204	if (strcmp(p, r->cl_server) != 0)
	205	return SVC_DENIED;
	206	return SVC_OK;
	207	}
	208
1da177e4 LT	209	static int nfs_callback_authenticate(struct svc_rqst *rqstp)
1da177e4 LT	210	{
adfa6f98	211	struct nfs_client *clp;
5216a8e7	212	RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
945b34a7	213	int ret = SVC_OK;
1da177e4 LT	214
1da177e4 LT	215	/* Don't talk to strangers */
ff052645	216	clp = nfs_find_client(svc_addr(rqstp), 4);
1da177e4 LT	217	if (clp == NULL)
1da177e4 LT	218	return SVC_DROP;
ad06e4bd	219
3110ff80	220	dprintk("%s: %s NFSv4 callback!\n", __func__,
ad06e4bd	221	svc_print_addr(rqstp, buf, sizeof(buf)));
ad06e4bd	222
1da177e4 LT	223	switch (rqstp->rq_authop->flavour) {
	224	case RPC_AUTH_NULL:
	225	if (rqstp->rq_proc != CB_NULL)
945b34a7	226	ret = SVC_DENIED;
1da177e4 LT	227	break;
	228	case RPC_AUTH_UNIX:
	229	break;
	230	case RPC_AUTH_GSS:
945b34a7 OK	231	ret = check_gss_callback_principal(clp, rqstp);
945b34a7 OK	232	break;
1da177e4	233	default:
945b34a7	234	ret = SVC_DENIED;
1da177e4	235	}
945b34a7 OK	236	nfs_put_client(clp);
945b34a7 OK	237	return ret;
1da177e4 LT	238	}
	239
	240	/*
	241	* Define NFS4 callback program
	242	*/
1da177e4 LT	243	static struct svc_version *nfs4_callback_version[] = {
	244	[1] = &nfs4_callback_version1,
	245	};
	246
	247	static struct svc_stat nfs4_callback_stats;
	248
	249	static struct svc_program nfs4_callback_program = {
	250	.pg_prog = NFS4_CALLBACK, /* RPC service number */
	251	.pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
	252	.pg_vers = nfs4_callback_version, /* version table */
	253	.pg_name = "NFSv4 callback", /* service name */
	254	.pg_class = "nfs", /* authentication class */
	255	.pg_stats = &nfs4_callback_stats,
	256	.pg_authenticate = nfs_callback_authenticate,
	257	};