[linux-block.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>
#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, 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 int param_get_portnr(char *buffer, struct kernel_param *kp)
{
	return param_get_uint(buffer, kp);
}
#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();

	/*
	 * 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;
}

/*
 * 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", 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);

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
	ret = svc_create_xprt(serv, "tcp", 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;
#endif	/* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */

	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();

	/*
	 * 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()) {
		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);
	}
	unlock_kernel();
	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,
};

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>
a43cde94 RL	20	#if defined(CONFIG_NFS_V4_1)
	21	#include <linux/sunrpc/bc_xprt.h>
	22	#endif
14c85021 ACM	23
	24	#include <net/inet_sock.h>
	25
4ce79717	26	#include "nfs4_fs.h"
1da177e4	27	#include "callback.h"
24c8dbbb	28	#include "internal.h"
1da177e4 LT	29
	30	#define NFSDBG_FACILITY NFSDBG_CALLBACK
	31
	32	struct nfs_callback_data {
	33	unsigned int users;
a43cde94	34	struct svc_serv *serv;
5afc597c	35	struct svc_rqst *rqst;
a277e33c	36	struct task_struct *task;
1da177e4 LT	37	};
1da177e4 LT	38
e82dc22d	39	static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
353ab6e9	40	static DEFINE_MUTEX(nfs_callback_mutex);
1da177e4 LT	41	static struct svc_program nfs4_callback_program;
1da177e4 LT	42
a72b4422	43	unsigned int nfs_callback_set_tcpport;
1da177e4	44	unsigned short nfs_callback_tcpport;
f738f517	45	unsigned short nfs_callback_tcpport6;
c140aa91	46	#define NFS_CALLBACK_MAXPORTNR (65535U)
7d4e2747	47
c140aa91	48	static int param_set_portnr(const char val, struct kernel_param kp)
7d4e2747	49	{
c140aa91 TM	50	unsigned long num;
	51	int ret;
	52
	53	if (!val)
	54	return -EINVAL;
	55	ret = strict_strtoul(val, 0, &num);
	56	if (ret == -EINVAL \|\| num > NFS_CALLBACK_MAXPORTNR)
7d4e2747	57	return -EINVAL;
c140aa91	58	((unsigned int )kp->arg) = num;
7d4e2747 DH	59	return 0;
	60	}
	61
c140aa91 TM	62	static int param_get_portnr(char buffer, struct kernel_param kp)
	63	{
	64	return param_get_uint(buffer, kp);
	65	}
	66	#define param_check_portnr(name, p) __param_check(name, p, unsigned int);
	67
	68	module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
1da177e4 LT	69
1da177e4 LT	70	/*
e82dc22d	71	* This is the NFSv4 callback kernel thread.
1da177e4	72	*/
a277e33c	73	static int
71468513	74	nfs4_callback_svc(void *vrqstp)
1da177e4	75	{
06e02d66	76	int err, preverr = 0;
a277e33c	77	struct svc_rqst *rqstp = vrqstp;
1da177e4	78
83144186	79	set_freezable();
1da177e4	80
a277e33c JL	81	/*
	82	* FIXME: do we really need to run this under the BKL? If so, please
	83	* add a comment about what it's intended to protect.
	84	*/
	85	lock_kernel();
	86	while (!kthread_should_stop()) {
1da177e4 LT	87	/*
	88	* Listen for a request on the socket
	89	*/
6fb2b47f	90	err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
06e02d66 JL	91	if (err == -EAGAIN \|\| err == -EINTR) {
06e02d66 JL	92	preverr = err;
1da177e4	93	continue;
06e02d66	94	}
1da177e4	95	if (err < 0) {
06e02d66 JL	96	if (err != preverr) {
	97	printk(KERN_WARNING "%s: unexpected error "
	98	"from svc_recv (%d)\n", __func__, err);
	99	preverr = err;
	100	}
	101	schedule_timeout_uninterruptible(HZ);
	102	continue;
1da177e4	103	}
06e02d66	104	preverr = err;
6fb2b47f	105	svc_process(rqstp);
1da177e4	106	}
1da177e4	107	unlock_kernel();
a277e33c	108	return 0;
1da177e4 LT	109	}
	110
	111	/*
71468513	112	* Prepare to bring up the NFSv4 callback service
1da177e4	113	*/
71468513 BH	114	struct svc_rqst *
71468513 BH	115	nfs4_callback_up(struct svc_serv *serv)
1da177e4	116	{
71468513	117	int ret;
482fb94e	118
26298caa	119	ret = svc_create_xprt(serv, "tcp", PF_INET,
9652ada3	120	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
482fb94e	121	if (ret <= 0)
8e60029f	122	goto out_err;
482fb94e	123	nfs_callback_tcpport = ret;
18de9735	124	dprintk("NFS: Callback listener port = %u (af %u)\n",
26298caa	125	nfs_callback_tcpport, PF_INET);
482fb94e	126
f738f517 CL	127	#if defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE)
	128	ret = svc_create_xprt(serv, "tcp", PF_INET6,
	129	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	130	if (ret > 0) {
	131	nfs_callback_tcpport6 = ret;
	132	dprintk("NFS: Callback listener port = %u (af %u)\n",
	133	nfs_callback_tcpport6, PF_INET6);
18fc3164 CL	134	} else if (ret == -EAFNOSUPPORT)
	135	ret = 0;
	136	else
f738f517 CL	137	goto out_err;
	138	#endif /* defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE) */
	139
71468513 BH	140	return svc_prepare_thread(serv, &serv->sv_pools[0]);
	141
	142	out_err:
	143	if (ret == 0)
	144	ret = -ENOMEM;
	145	return ERR_PTR(ret);
	146	}
	147
a43cde94 RL	148	#if defined(CONFIG_NFS_V4_1)
	149	/*
	150	* The callback service for NFSv4.1 callbacks
	151	*/
	152	static int
	153	nfs41_callback_svc(void *vrqstp)
	154	{
	155	struct svc_rqst *rqstp = vrqstp;
	156	struct svc_serv *serv = rqstp->rq_server;
	157	struct rpc_rqst *req;
	158	int error;
	159	DEFINE_WAIT(wq);
	160
	161	set_freezable();
	162
	163	/*
	164	* FIXME: do we really need to run this under the BKL? If so, please
	165	* add a comment about what it's intended to protect.
	166	*/
	167	lock_kernel();
	168	while (!kthread_should_stop()) {
	169	prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
	170	spin_lock_bh(&serv->sv_cb_lock);
	171	if (!list_empty(&serv->sv_cb_list)) {
	172	req = list_first_entry(&serv->sv_cb_list,
	173	struct rpc_rqst, rq_bc_list);
	174	list_del(&req->rq_bc_list);
	175	spin_unlock_bh(&serv->sv_cb_lock);
	176	dprintk("Invoking bc_svc_process()\n");
	177	error = bc_svc_process(serv, req, rqstp);
	178	dprintk("bc_svc_process() returned w/ error code= %d\n",
	179	error);
	180	} else {
	181	spin_unlock_bh(&serv->sv_cb_lock);
	182	schedule();
	183	}
	184	finish_wait(&serv->sv_cb_waitq, &wq);
	185	}
	186	unlock_kernel();
a43cde94 RL	187	return 0;
	188	}
	189
	190	/*
	191	* Bring up the NFSv4.1 callback service
	192	*/
	193	struct svc_rqst *
	194	nfs41_callback_up(struct svc_serv serv, struct rpc_xprt xprt)
	195	{
8f975242 BH	196	struct svc_xprt *bc_xprt;
	197	struct svc_rqst *rqstp = ERR_PTR(-ENOMEM);
	198
	199	dprintk("--> %s\n", __func__);
	200	/* Create a svc_sock for the service */
	201	bc_xprt = svc_sock_create(serv, xprt->prot);
	202	if (!bc_xprt)
	203	goto out;
	204
a43cde94 RL	205	/*
	206	* Save the svc_serv in the transport so that it can
	207	* be referenced when the session backchannel is initialized
	208	*/
8f975242	209	serv->bc_xprt = bc_xprt;
a43cde94 RL	210	xprt->bc_serv = serv;
	211
	212	INIT_LIST_HEAD(&serv->sv_cb_list);
	213	spin_lock_init(&serv->sv_cb_lock);
	214	init_waitqueue_head(&serv->sv_cb_waitq);
8f975242 BH	215	rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]);
	216	if (IS_ERR(rqstp))
	217	svc_sock_destroy(bc_xprt);
	218	out:
	219	dprintk("--> %s return %p\n", __func__, rqstp);
	220	return rqstp;
a43cde94 RL	221	}
	222
	223	static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
	224	struct svc_serv serv, struct rpc_xprt xprt,
	225	struct svc_rqst rqstpp, int (callback_svc)(void *vrqstp))
	226	{
	227	if (minorversion) {
	228	*rqstpp = nfs41_callback_up(serv, xprt);
	229	*callback_svc = nfs41_callback_svc;
	230	}
	231	return minorversion;
	232	}
	233
	234	static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
	235	struct nfs_callback_data *cb_info)
	236	{
	237	if (minorversion)
	238	xprt->bc_serv = cb_info->serv;
	239	}
	240	#else
	241	static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
	242	struct svc_serv serv, struct rpc_xprt xprt,
	243	struct svc_rqst rqstpp, int (callback_svc)(void *vrqstp))
	244	{
	245	return 0;
	246	}
	247
	248	static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
	249	struct nfs_callback_data *cb_info)
	250	{
	251	}
	252	#endif /* CONFIG_NFS_V4_1 */
	253
71468513 BH	254	/*
	255	* Bring up the callback thread if it is not already up.
	256	*/
	257	int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
	258	{
	259	struct svc_serv *serv = NULL;
	260	struct svc_rqst *rqstp;
	261	int (callback_svc)(void vrqstp);
e82dc22d	262	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
71468513 BH	263	char svc_name[12];
71468513 BH	264	int ret = 0;
a43cde94	265	int minorversion_setup;
71468513 BH	266
71468513 BH	267	mutex_lock(&nfs_callback_mutex);
e82dc22d AA	268	if (cb_info->users++ \|\| cb_info->task != NULL) {
e82dc22d AA	269	nfs_callback_bc_serv(minorversion, xprt, cb_info);
71468513	270	goto out;
a43cde94	271	}
71468513 BH	272	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
	273	if (!serv) {
	274	ret = -ENOMEM;
	275	goto out_err;
	276	}
	277
a43cde94 RL	278	minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion,
	279	serv, xprt, &rqstp, &callback_svc);
	280	if (!minorversion_setup) {
	281	/* v4.0 callback setup */
71468513 BH	282	rqstp = nfs4_callback_up(serv);
71468513 BH	283	callback_svc = nfs4_callback_svc;
71468513 BH	284	}
	285
	286	if (IS_ERR(rqstp)) {
	287	ret = PTR_ERR(rqstp);
8e60029f	288	goto out_err;
a277e33c JL	289	}
	290
	291	svc_sock_update_bufs(serv);
a277e33c	292
71468513	293	sprintf(svc_name, "nfsv4.%u-svc", minorversion);
e82dc22d AA	294	cb_info->serv = serv;
	295	cb_info->rqst = rqstp;
	296	cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
	297	if (IS_ERR(cb_info->task)) {
	298	ret = PTR_ERR(cb_info->task);
	299	svc_exit_thread(cb_info->rqst);
	300	cb_info->rqst = NULL;
	301	cb_info->task = NULL;
a277e33c JL	302	goto out_err;
a277e33c JL	303	}
1da177e4	304	out:
8e60029f JL	305	/*
8e60029f JL	306	* svc_create creates the svc_serv with sv_nrthreads == 1, and then
a277e33c	307	* svc_prepare_thread increments that. So we need to call svc_destroy
8e60029f JL	308	* on both success and failure so that the refcount is 1 when the
	309	* thread exits.
	310	*/
	311	if (serv)
	312	svc_destroy(serv);
353ab6e9	313	mutex_unlock(&nfs_callback_mutex);
1da177e4	314	return ret;
8e60029f	315	out_err:
18de9735 CL	316	dprintk("NFS: Couldn't create callback socket or server thread; "
18de9735 CL	317	"err = %d\n", ret);
e82dc22d	318	cb_info->users--;
1da177e4 LT	319	goto out;
	320	}
	321
	322	/*
5afc597c	323	* Kill the callback thread if it's no longer being used.
1da177e4	324	*/
e82dc22d	325	void nfs_callback_down(int minorversion)
1da177e4	326	{
e82dc22d AA	327	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
e82dc22d AA	328
353ab6e9	329	mutex_lock(&nfs_callback_mutex);
e82dc22d AA	330	cb_info->users--;
	331	if (cb_info->users == 0 && cb_info->task != NULL) {
	332	kthread_stop(cb_info->task);
	333	svc_exit_thread(cb_info->rqst);
	334	cb_info->serv = NULL;
	335	cb_info->rqst = NULL;
	336	cb_info->task = NULL;
5afc597c	337	}
353ab6e9	338	mutex_unlock(&nfs_callback_mutex);
1da177e4 LT	339	}
1da177e4 LT	340
945b34a7 OK	341	static int check_gss_callback_principal(struct nfs_client *clp,
	342	struct svc_rqst *rqstp)
	343	{
	344	struct rpc_clnt *r = clp->cl_rpcclient;
	345	char *p = svc_gss_principal(rqstp);
	346
	347	/*
	348	* It might just be a normal user principal, in which case
	349	* userspace won't bother to tell us the name at all.
	350	*/
	351	if (p == NULL)
	352	return SVC_DENIED;
	353
	354	/* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
	355
	356	if (memcmp(p, "nfs@", 4) != 0)
	357	return SVC_DENIED;
	358	p += 4;
	359	if (strcmp(p, r->cl_server) != 0)
	360	return SVC_DENIED;
	361	return SVC_OK;
	362	}
	363
1da177e4 LT	364	static int nfs_callback_authenticate(struct svc_rqst *rqstp)
1da177e4 LT	365	{
adfa6f98	366	struct nfs_client *clp;
5216a8e7	367	RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
945b34a7	368	int ret = SVC_OK;
1da177e4 LT	369
1da177e4 LT	370	/* Don't talk to strangers */
ff052645	371	clp = nfs_find_client(svc_addr(rqstp), 4);
1da177e4 LT	372	if (clp == NULL)
1da177e4 LT	373	return SVC_DROP;
ad06e4bd	374
3110ff80	375	dprintk("%s: %s NFSv4 callback!\n", __func__,
ad06e4bd	376	svc_print_addr(rqstp, buf, sizeof(buf)));
ad06e4bd	377
1da177e4 LT	378	switch (rqstp->rq_authop->flavour) {
	379	case RPC_AUTH_NULL:
	380	if (rqstp->rq_proc != CB_NULL)
945b34a7	381	ret = SVC_DENIED;
1da177e4 LT	382	break;
	383	case RPC_AUTH_UNIX:
	384	break;
	385	case RPC_AUTH_GSS:
945b34a7 OK	386	ret = check_gss_callback_principal(clp, rqstp);
945b34a7 OK	387	break;
1da177e4	388	default:
945b34a7	389	ret = SVC_DENIED;
1da177e4	390	}
945b34a7 OK	391	nfs_put_client(clp);
945b34a7 OK	392	return ret;
1da177e4 LT	393	}
	394
	395	/*
	396	* Define NFS4 callback program
	397	*/
1da177e4 LT	398	static struct svc_version *nfs4_callback_version[] = {
	399	[1] = &nfs4_callback_version1,
	400	};
	401
	402	static struct svc_stat nfs4_callback_stats;
	403
	404	static struct svc_program nfs4_callback_program = {
	405	.pg_prog = NFS4_CALLBACK, /* RPC service number */
	406	.pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
	407	.pg_vers = nfs4_callback_version, /* version table */
	408	.pg_name = "NFSv4 callback", /* service name */
	409	.pg_class = "nfs", /* authentication class */
	410	.pg_stats = &nfs4_callback_stats,
	411	.pg_authenticate = nfs_callback_authenticate,
	412	};