[mirror_ubuntu-zesty-kernel.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/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>
#if defined(CONFIG_NFS_V4_1)
#include <linux/sunrpc/bc_xprt.h>
#endif

#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_serv *serv;
	struct svc_rqst *rqst;
	struct task_struct *task;
};

static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
static DEFINE_MUTEX(nfs_callback_mutex);
static struct svc_program nfs4_callback_program;

unsigned int nfs_callback_set_tcpport;
unsigned short nfs_callback_tcpport;
unsigned short nfs_callback_tcpport6;
#define NFS_CALLBACK_MAXPORTNR (65535U)

static int param_set_portnr(const char *val, const struct kernel_param *kp)
{
	unsigned long num;
	int ret;

	if (!val)
		return -EINVAL;
	ret = strict_strtoul(val, 0, &num);
	if (ret == -EINVAL || num > NFS_CALLBACK_MAXPORTNR)
		return -EINVAL;
	*((unsigned int *)kp->arg) = num;
	return 0;
}
static struct kernel_param_ops param_ops_portnr = {
	.set = param_set_portnr,
	.get = param_get_uint,
};
#define param_check_portnr(name, p) __param_check(name, p, unsigned int);

module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);

/*
 * This is the NFSv4 callback kernel thread.
 */
static int
nfs4_callback_svc(void *vrqstp)
{
	int err, preverr = 0;
	struct svc_rqst *rqstp = vrqstp;

	set_freezable();

	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);
	}
	return 0;
}

/*
 * Prepare to bring up the NFSv4 callback service
 */
struct svc_rqst *
nfs4_callback_up(struct svc_serv *serv)
{
	int ret;

	ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET,
				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, PF_INET);

	ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET6,
				nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	if (ret > 0) {
		nfs_callback_tcpport6 = ret;
		dprintk("NFS: Callback listener port = %u (af %u)\n",
				nfs_callback_tcpport6, PF_INET6);
	} else if (ret == -EAFNOSUPPORT)
		ret = 0;
	else
		goto out_err;

	return svc_prepare_thread(serv, &serv->sv_pools[0]);

out_err:
	if (ret == 0)
		ret = -ENOMEM;
	return ERR_PTR(ret);
}

#if defined(CONFIG_NFS_V4_1)
/*
 * The callback service for NFSv4.1 callbacks
 */
static int
nfs41_callback_svc(void *vrqstp)
{
	struct svc_rqst *rqstp = vrqstp;
	struct svc_serv *serv = rqstp->rq_server;
	struct rpc_rqst *req;
	int error;
	DEFINE_WAIT(wq);

	set_freezable();

	while (!kthread_should_stop()) {
		prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
		spin_lock_bh(&serv->sv_cb_lock);
		if (!list_empty(&serv->sv_cb_list)) {
			req = list_first_entry(&serv->sv_cb_list,
					struct rpc_rqst, rq_bc_list);
			list_del(&req->rq_bc_list);
			spin_unlock_bh(&serv->sv_cb_lock);
			dprintk("Invoking bc_svc_process()\n");
			error = bc_svc_process(serv, req, rqstp);
			dprintk("bc_svc_process() returned w/ error code= %d\n",
				error);
		} else {
			spin_unlock_bh(&serv->sv_cb_lock);
			schedule();
		}
		finish_wait(&serv->sv_cb_waitq, &wq);
	}
	return 0;
}

/*
 * Bring up the NFSv4.1 callback service
 */
struct svc_rqst *
nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
{
	struct svc_xprt *bc_xprt;
	struct svc_rqst *rqstp = ERR_PTR(-ENOMEM);

	dprintk("--> %s\n", __func__);
	/* Create a svc_sock for the service */
	bc_xprt = svc_sock_create(serv, xprt->prot);
	if (!bc_xprt)
		goto out;

	/*
	 * Save the svc_serv in the transport so that it can
	 * be referenced when the session backchannel is initialized
	 */
	serv->bc_xprt = bc_xprt;
	xprt->bc_serv = serv;

	INIT_LIST_HEAD(&serv->sv_cb_list);
	spin_lock_init(&serv->sv_cb_lock);
	init_waitqueue_head(&serv->sv_cb_waitq);
	rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]);
	if (IS_ERR(rqstp))
		svc_sock_destroy(bc_xprt);
out:
	dprintk("--> %s return %p\n", __func__, rqstp);
	return rqstp;
}

static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
		struct svc_serv *serv, struct rpc_xprt *xprt,
		struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
{
	if (minorversion) {
		*rqstpp = nfs41_callback_up(serv, xprt);
		*callback_svc = nfs41_callback_svc;
	}
	return minorversion;
}

static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
		struct nfs_callback_data *cb_info)
{
	if (minorversion)
		xprt->bc_serv = cb_info->serv;
}
#else
static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
		struct svc_serv *serv, struct rpc_xprt *xprt,
		struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
{
	return 0;
}

static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
		struct nfs_callback_data *cb_info)
{
}
#endif /* CONFIG_NFS_V4_1 */

/*
 * Bring up the callback thread if it is not already up.
 */
int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
{
	struct svc_serv *serv = NULL;
	struct svc_rqst *rqstp;
	int (*callback_svc)(void *vrqstp);
	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	char svc_name[12];
	int ret = 0;
	int minorversion_setup;

	mutex_lock(&nfs_callback_mutex);
	if (cb_info->users++ || cb_info->task != NULL) {
		nfs_callback_bc_serv(minorversion, xprt, cb_info);
		goto out;
	}
	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
	if (!serv) {
		ret = -ENOMEM;
		goto out_err;
	}

	minorversion_setup =  nfs_minorversion_callback_svc_setup(minorversion,
					serv, xprt, &rqstp, &callback_svc);
	if (!minorversion_setup) {
		/* v4.0 callback setup */
		rqstp = nfs4_callback_up(serv);
		callback_svc = nfs4_callback_svc;
	}

	if (IS_ERR(rqstp)) {
		ret = PTR_ERR(rqstp);
		goto out_err;
	}

	svc_sock_update_bufs(serv);

	sprintf(svc_name, "nfsv4.%u-svc", minorversion);
	cb_info->serv = serv;
	cb_info->rqst = rqstp;
	cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
	if (IS_ERR(cb_info->task)) {
		ret = PTR_ERR(cb_info->task);
		svc_exit_thread(cb_info->rqst);
		cb_info->rqst = NULL;
		cb_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);
	cb_info->users--;
	goto out;
}

/*
 * Kill the callback thread if it's no longer being used.
 */
void nfs_callback_down(int minorversion)
{
	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];

	mutex_lock(&nfs_callback_mutex);
	cb_info->users--;
	if (cb_info->users == 0 && cb_info->task != NULL) {
		kthread_stop(cb_info->task);
		svc_exit_thread(cb_info->rqst);
		cb_info->serv = NULL;
		cb_info->rqst = NULL;
		cb_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,
	[4] = &nfs4_callback_version4,
};

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>
1da177e4 LT	12	#include <linux/sunrpc/svc.h>
	13	#include <linux/sunrpc/svcsock.h>
	14	#include <linux/nfs_fs.h>
353ab6e9	15	#include <linux/mutex.h>
83144186	16	#include <linux/freezer.h>
a277e33c	17	#include <linux/kthread.h>
945b34a7	18	#include <linux/sunrpc/svcauth_gss.h>
a43cde94 RL	19	#if defined(CONFIG_NFS_V4_1)
	20	#include <linux/sunrpc/bc_xprt.h>
	21	#endif
14c85021 ACM	22
	23	#include <net/inet_sock.h>
	24
4ce79717	25	#include "nfs4_fs.h"
1da177e4	26	#include "callback.h"
24c8dbbb	27	#include "internal.h"
1da177e4 LT	28
	29	#define NFSDBG_FACILITY NFSDBG_CALLBACK
	30
	31	struct nfs_callback_data {
	32	unsigned int users;
a43cde94	33	struct svc_serv *serv;
5afc597c	34	struct svc_rqst *rqst;
a277e33c	35	struct task_struct *task;
1da177e4 LT	36	};
1da177e4 LT	37
e82dc22d	38	static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
353ab6e9	39	static DEFINE_MUTEX(nfs_callback_mutex);
1da177e4 LT	40	static struct svc_program nfs4_callback_program;
1da177e4 LT	41
a72b4422	42	unsigned int nfs_callback_set_tcpport;
1da177e4	43	unsigned short nfs_callback_tcpport;
f738f517	44	unsigned short nfs_callback_tcpport6;
c140aa91	45	#define NFS_CALLBACK_MAXPORTNR (65535U)
7d4e2747	46
9bbb9e5a	47	static int param_set_portnr(const char val, const struct kernel_param kp)
7d4e2747	48	{
c140aa91 TM	49	unsigned long num;
	50	int ret;
	51
	52	if (!val)
	53	return -EINVAL;
	54	ret = strict_strtoul(val, 0, &num);
	55	if (ret == -EINVAL \|\| num > NFS_CALLBACK_MAXPORTNR)
7d4e2747	56	return -EINVAL;
c140aa91	57	((unsigned int )kp->arg) = num;
7d4e2747 DH	58	return 0;
7d4e2747 DH	59	}
9bbb9e5a RR	60	static struct kernel_param_ops param_ops_portnr = {
	61	.set = param_set_portnr,
	62	.get = param_get_uint,
	63	};
c140aa91 TM	64	#define param_check_portnr(name, p) __param_check(name, p, unsigned int);
	65
	66	module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
1da177e4 LT	67
1da177e4 LT	68	/*
e82dc22d	69	* This is the NFSv4 callback kernel thread.
1da177e4	70	*/
a277e33c	71	static int
71468513	72	nfs4_callback_svc(void *vrqstp)
1da177e4	73	{
06e02d66	74	int err, preverr = 0;
a277e33c	75	struct svc_rqst *rqstp = vrqstp;
1da177e4	76
83144186	77	set_freezable();
1da177e4	78
a277e33c	79	while (!kthread_should_stop()) {
1da177e4 LT	80	/*
	81	* Listen for a request on the socket
	82	*/
6fb2b47f	83	err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
06e02d66 JL	84	if (err == -EAGAIN \|\| err == -EINTR) {
06e02d66 JL	85	preverr = err;
1da177e4	86	continue;
06e02d66	87	}
1da177e4	88	if (err < 0) {
06e02d66 JL	89	if (err != preverr) {
	90	printk(KERN_WARNING "%s: unexpected error "
	91	"from svc_recv (%d)\n", __func__, err);
	92	preverr = err;
	93	}
	94	schedule_timeout_uninterruptible(HZ);
	95	continue;
1da177e4	96	}
06e02d66	97	preverr = err;
6fb2b47f	98	svc_process(rqstp);
1da177e4	99	}
a277e33c	100	return 0;
1da177e4 LT	101	}
	102
	103	/*
71468513	104	* Prepare to bring up the NFSv4 callback service
1da177e4	105	*/
71468513 BH	106	struct svc_rqst *
71468513 BH	107	nfs4_callback_up(struct svc_serv *serv)
1da177e4	108	{
71468513	109	int ret;
482fb94e	110
fc5d00b0	111	ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET,
9652ada3	112	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
482fb94e	113	if (ret <= 0)
8e60029f	114	goto out_err;
482fb94e	115	nfs_callback_tcpport = ret;
18de9735	116	dprintk("NFS: Callback listener port = %u (af %u)\n",
26298caa	117	nfs_callback_tcpport, PF_INET);
482fb94e	118
fc5d00b0	119	ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET6,
f738f517 CL	120	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	121	if (ret > 0) {
	122	nfs_callback_tcpport6 = ret;
	123	dprintk("NFS: Callback listener port = %u (af %u)\n",
	124	nfs_callback_tcpport6, PF_INET6);
18fc3164 CL	125	} else if (ret == -EAFNOSUPPORT)
	126	ret = 0;
	127	else
f738f517	128	goto out_err;
f738f517	129
71468513 BH	130	return svc_prepare_thread(serv, &serv->sv_pools[0]);
	131
	132	out_err:
	133	if (ret == 0)
	134	ret = -ENOMEM;
	135	return ERR_PTR(ret);
	136	}
	137
a43cde94 RL	138	#if defined(CONFIG_NFS_V4_1)
	139	/*
	140	* The callback service for NFSv4.1 callbacks
	141	*/
	142	static int
	143	nfs41_callback_svc(void *vrqstp)
	144	{
	145	struct svc_rqst *rqstp = vrqstp;
	146	struct svc_serv *serv = rqstp->rq_server;
	147	struct rpc_rqst *req;
	148	int error;
	149	DEFINE_WAIT(wq);
	150
	151	set_freezable();
	152
a43cde94 RL	153	while (!kthread_should_stop()) {
	154	prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
	155	spin_lock_bh(&serv->sv_cb_lock);
	156	if (!list_empty(&serv->sv_cb_list)) {
	157	req = list_first_entry(&serv->sv_cb_list,
	158	struct rpc_rqst, rq_bc_list);
	159	list_del(&req->rq_bc_list);
	160	spin_unlock_bh(&serv->sv_cb_lock);
	161	dprintk("Invoking bc_svc_process()\n");
	162	error = bc_svc_process(serv, req, rqstp);
	163	dprintk("bc_svc_process() returned w/ error code= %d\n",
	164	error);
	165	} else {
	166	spin_unlock_bh(&serv->sv_cb_lock);
	167	schedule();
	168	}
	169	finish_wait(&serv->sv_cb_waitq, &wq);
	170	}
a43cde94 RL	171	return 0;
	172	}
	173
	174	/*
	175	* Bring up the NFSv4.1 callback service
	176	*/
	177	struct svc_rqst *
	178	nfs41_callback_up(struct svc_serv serv, struct rpc_xprt xprt)
	179	{
8f975242 BH	180	struct svc_xprt *bc_xprt;
	181	struct svc_rqst *rqstp = ERR_PTR(-ENOMEM);
	182
	183	dprintk("--> %s\n", __func__);
	184	/* Create a svc_sock for the service */
	185	bc_xprt = svc_sock_create(serv, xprt->prot);
	186	if (!bc_xprt)
	187	goto out;
	188
a43cde94 RL	189	/*
	190	* Save the svc_serv in the transport so that it can
	191	* be referenced when the session backchannel is initialized
	192	*/
8f975242	193	serv->bc_xprt = bc_xprt;
a43cde94 RL	194	xprt->bc_serv = serv;
	195
	196	INIT_LIST_HEAD(&serv->sv_cb_list);
	197	spin_lock_init(&serv->sv_cb_lock);
	198	init_waitqueue_head(&serv->sv_cb_waitq);
8f975242 BH	199	rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]);
	200	if (IS_ERR(rqstp))
	201	svc_sock_destroy(bc_xprt);
	202	out:
	203	dprintk("--> %s return %p\n", __func__, rqstp);
	204	return rqstp;
a43cde94 RL	205	}
	206
	207	static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
	208	struct svc_serv serv, struct rpc_xprt xprt,
	209	struct svc_rqst rqstpp, int (callback_svc)(void *vrqstp))
	210	{
	211	if (minorversion) {
	212	*rqstpp = nfs41_callback_up(serv, xprt);
	213	*callback_svc = nfs41_callback_svc;
	214	}
	215	return minorversion;
	216	}
	217
	218	static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
	219	struct nfs_callback_data *cb_info)
	220	{
	221	if (minorversion)
	222	xprt->bc_serv = cb_info->serv;
	223	}
	224	#else
	225	static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
	226	struct svc_serv serv, struct rpc_xprt xprt,
	227	struct svc_rqst rqstpp, int (callback_svc)(void *vrqstp))
	228	{
	229	return 0;
	230	}
	231
	232	static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
	233	struct nfs_callback_data *cb_info)
	234	{
	235	}
	236	#endif /* CONFIG_NFS_V4_1 */
	237
71468513 BH	238	/*
	239	* Bring up the callback thread if it is not already up.
	240	*/
	241	int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
	242	{
	243	struct svc_serv *serv = NULL;
	244	struct svc_rqst *rqstp;
	245	int (callback_svc)(void vrqstp);
e82dc22d	246	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
71468513 BH	247	char svc_name[12];
71468513 BH	248	int ret = 0;
a43cde94	249	int minorversion_setup;
71468513 BH	250
71468513 BH	251	mutex_lock(&nfs_callback_mutex);
e82dc22d AA	252	if (cb_info->users++ \|\| cb_info->task != NULL) {
e82dc22d AA	253	nfs_callback_bc_serv(minorversion, xprt, cb_info);
71468513	254	goto out;
a43cde94	255	}
71468513 BH	256	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
	257	if (!serv) {
	258	ret = -ENOMEM;
	259	goto out_err;
	260	}
	261
a43cde94 RL	262	minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion,
	263	serv, xprt, &rqstp, &callback_svc);
	264	if (!minorversion_setup) {
	265	/* v4.0 callback setup */
71468513 BH	266	rqstp = nfs4_callback_up(serv);
71468513 BH	267	callback_svc = nfs4_callback_svc;
71468513 BH	268	}
	269
	270	if (IS_ERR(rqstp)) {
	271	ret = PTR_ERR(rqstp);
8e60029f	272	goto out_err;
a277e33c JL	273	}
	274
	275	svc_sock_update_bufs(serv);
a277e33c	276
71468513	277	sprintf(svc_name, "nfsv4.%u-svc", minorversion);
e82dc22d AA	278	cb_info->serv = serv;
	279	cb_info->rqst = rqstp;
	280	cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
	281	if (IS_ERR(cb_info->task)) {
	282	ret = PTR_ERR(cb_info->task);
	283	svc_exit_thread(cb_info->rqst);
	284	cb_info->rqst = NULL;
	285	cb_info->task = NULL;
a277e33c JL	286	goto out_err;
a277e33c JL	287	}
1da177e4	288	out:
8e60029f JL	289	/*
8e60029f JL	290	* svc_create creates the svc_serv with sv_nrthreads == 1, and then
a277e33c	291	* svc_prepare_thread increments that. So we need to call svc_destroy
8e60029f JL	292	* on both success and failure so that the refcount is 1 when the
	293	* thread exits.
	294	*/
	295	if (serv)
	296	svc_destroy(serv);
353ab6e9	297	mutex_unlock(&nfs_callback_mutex);
1da177e4	298	return ret;
8e60029f	299	out_err:
18de9735 CL	300	dprintk("NFS: Couldn't create callback socket or server thread; "
18de9735 CL	301	"err = %d\n", ret);
e82dc22d	302	cb_info->users--;
1da177e4 LT	303	goto out;
	304	}
	305
	306	/*
5afc597c	307	* Kill the callback thread if it's no longer being used.
1da177e4	308	*/
e82dc22d	309	void nfs_callback_down(int minorversion)
1da177e4	310	{
e82dc22d AA	311	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
e82dc22d AA	312
353ab6e9	313	mutex_lock(&nfs_callback_mutex);
e82dc22d AA	314	cb_info->users--;
	315	if (cb_info->users == 0 && cb_info->task != NULL) {
	316	kthread_stop(cb_info->task);
	317	svc_exit_thread(cb_info->rqst);
	318	cb_info->serv = NULL;
	319	cb_info->rqst = NULL;
	320	cb_info->task = NULL;
5afc597c	321	}
353ab6e9	322	mutex_unlock(&nfs_callback_mutex);
1da177e4 LT	323	}
1da177e4 LT	324
945b34a7 OK	325	static int check_gss_callback_principal(struct nfs_client *clp,
	326	struct svc_rqst *rqstp)
	327	{
	328	struct rpc_clnt *r = clp->cl_rpcclient;
	329	char *p = svc_gss_principal(rqstp);
	330
	331	/*
	332	* It might just be a normal user principal, in which case
	333	* userspace won't bother to tell us the name at all.
	334	*/
	335	if (p == NULL)
	336	return SVC_DENIED;
	337
	338	/* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
	339
	340	if (memcmp(p, "nfs@", 4) != 0)
	341	return SVC_DENIED;
	342	p += 4;
	343	if (strcmp(p, r->cl_server) != 0)
	344	return SVC_DENIED;
	345	return SVC_OK;
	346	}
	347
1da177e4 LT	348	static int nfs_callback_authenticate(struct svc_rqst *rqstp)
1da177e4 LT	349	{
adfa6f98	350	struct nfs_client *clp;
5216a8e7	351	RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
945b34a7	352	int ret = SVC_OK;
1da177e4 LT	353
1da177e4 LT	354	/* Don't talk to strangers */
ff052645	355	clp = nfs_find_client(svc_addr(rqstp), 4);
1da177e4 LT	356	if (clp == NULL)
1da177e4 LT	357	return SVC_DROP;
ad06e4bd	358
3110ff80	359	dprintk("%s: %s NFSv4 callback!\n", __func__,
ad06e4bd	360	svc_print_addr(rqstp, buf, sizeof(buf)));
ad06e4bd	361
1da177e4 LT	362	switch (rqstp->rq_authop->flavour) {
	363	case RPC_AUTH_NULL:
	364	if (rqstp->rq_proc != CB_NULL)
945b34a7	365	ret = SVC_DENIED;
1da177e4 LT	366	break;
	367	case RPC_AUTH_UNIX:
	368	break;
	369	case RPC_AUTH_GSS:
945b34a7 OK	370	ret = check_gss_callback_principal(clp, rqstp);
945b34a7 OK	371	break;
1da177e4	372	default:
945b34a7	373	ret = SVC_DENIED;
1da177e4	374	}
945b34a7 OK	375	nfs_put_client(clp);
945b34a7 OK	376	return ret;
1da177e4 LT	377	}
	378
	379	/*
	380	* Define NFS4 callback program
	381	*/
1da177e4 LT	382	static struct svc_version *nfs4_callback_version[] = {
1da177e4 LT	383	[1] = &nfs4_callback_version1,
07bccc2d	384	[4] = &nfs4_callback_version4,
1da177e4 LT	385	};
	386
	387	static struct svc_stat nfs4_callback_stats;
	388
	389	static struct svc_program nfs4_callback_program = {
	390	.pg_prog = NFS4_CALLBACK, /* RPC service number */
	391	.pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
	392	.pg_vers = nfs4_callback_version, /* version table */
	393	.pg_name = "NFSv4 callback", /* service name */
	394	.pg_class = "nfs", /* authentication class */
	395	.pg_stats = &nfs4_callback_stats,
	396	.pg_authenticate = nfs_callback_authenticate,
	397	};