[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/sched/signal.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/nfs_fs.h>
#include <linux/errno.h>
#include <linux/mutex.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/sunrpc/bc_xprt.h>

#include <net/inet_sock.h>

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

#define NFSDBG_FACILITY NFSDBG_CALLBACK

struct nfs_callback_data {
	unsigned int users;
	struct svc_serv *serv;
};

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;

static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net)
{
	int ret;
	struct nfs_net *nn = net_generic(net, nfs_net_id);

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

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

out_err:
	return (ret) ? ret : -ENOMEM;
}

/*
 * This is the NFSv4 callback kernel thread.
 */
static int
nfs4_callback_svc(void *vrqstp)
{
	int err;
	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)
			continue;
		svc_process(rqstp);
	}
	return 0;
}

#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()) {
		if (try_to_freeze())
			continue;

		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);
			finish_wait(&serv->sv_cb_waitq, &wq);
			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);
		}
		flush_signals(current);
	}
	return 0;
}

static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
		struct svc_serv *serv)
{
	if (minorversion)
		/*
		 * Save the svc_serv in the transport so that it can
		 * be referenced when the session backchannel is initialized
		 */
		xprt->bc_serv = serv;
}
#else
static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
		struct svc_serv *serv)
{
}
#endif /* CONFIG_NFS_V4_1 */

static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
				  struct svc_serv *serv)
{
	int nrservs = nfs_callback_nr_threads;
	int ret;

	nfs_callback_bc_serv(minorversion, xprt, serv);

	if (nrservs < NFS4_MIN_NR_CALLBACK_THREADS)
		nrservs = NFS4_MIN_NR_CALLBACK_THREADS;

	if (serv->sv_nrthreads-1 == nrservs)
		return 0;

	ret = serv->sv_ops->svo_setup(serv, NULL, nrservs);
	if (ret) {
		serv->sv_ops->svo_setup(serv, NULL, 0);
		return ret;
	}
	dprintk("nfs_callback_up: service started\n");
	return 0;
}

static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
{
	struct nfs_net *nn = net_generic(net, nfs_net_id);

	if (--nn->cb_users[minorversion])
		return;

	dprintk("NFS: destroy per-net callback data; net=%p\n", net);
	svc_shutdown_net(serv, net);
}

static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
			       struct net *net, struct rpc_xprt *xprt)
{
	struct nfs_net *nn = net_generic(net, nfs_net_id);
	int ret;

	if (nn->cb_users[minorversion]++)
		return 0;

	dprintk("NFS: create per-net callback data; net=%p\n", net);

	ret = svc_bind(serv, net);
	if (ret < 0) {
		printk(KERN_WARNING "NFS: bind callback service failed\n");
		goto err_bind;
	}

	ret = -EPROTONOSUPPORT;
	if (!IS_ENABLED(CONFIG_NFS_V4_1) || minorversion == 0)
		ret = nfs4_callback_up_net(serv, net);
	else if (xprt->ops->bc_up)
		ret = xprt->ops->bc_up(serv, net);

	if (ret < 0) {
		printk(KERN_ERR "NFS: callback service start failed\n");
		goto err_socks;
	}
	return 0;

err_socks:
	svc_rpcb_cleanup(serv, net);
err_bind:
	nn->cb_users[minorversion]--;
	dprintk("NFS: Couldn't create callback socket: err = %d; "
			"net = %p\n", ret, net);
	return ret;
}

static struct svc_serv_ops nfs40_cb_sv_ops = {
	.svo_function		= nfs4_callback_svc,
	.svo_enqueue_xprt	= svc_xprt_do_enqueue,
	.svo_setup		= svc_set_num_threads,
	.svo_module		= THIS_MODULE,
};
#if defined(CONFIG_NFS_V4_1)
static struct svc_serv_ops nfs41_cb_sv_ops = {
	.svo_function		= nfs41_callback_svc,
	.svo_enqueue_xprt	= svc_xprt_do_enqueue,
	.svo_setup		= svc_set_num_threads,
	.svo_module		= THIS_MODULE,
};

struct svc_serv_ops *nfs4_cb_sv_ops[] = {
	[0] = &nfs40_cb_sv_ops,
	[1] = &nfs41_cb_sv_ops,
};
#else
struct svc_serv_ops *nfs4_cb_sv_ops[] = {
	[0] = &nfs40_cb_sv_ops,
	[1] = NULL,
};
#endif

static struct svc_serv *nfs_callback_create_svc(int minorversion)
{
	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	struct svc_serv *serv;
	struct svc_serv_ops *sv_ops;

	/*
	 * Check whether we're already up and running.
	 */
	if (cb_info->serv) {
		/*
		 * Note: increase service usage, because later in case of error
		 * svc_destroy() will be called.
		 */
		svc_get(cb_info->serv);
		return cb_info->serv;
	}

	switch (minorversion) {
	case 0:
		sv_ops = nfs4_cb_sv_ops[0];
		break;
	default:
		sv_ops = nfs4_cb_sv_ops[1];
	}

	if (sv_ops == NULL)
		return ERR_PTR(-ENOTSUPP);

	/*
	 * Sanity check: if there's no task,
	 * we should be the first user ...
	 */
	if (cb_info->users)
		printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
			cb_info->users);

	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, sv_ops);
	if (!serv) {
		printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
		return ERR_PTR(-ENOMEM);
	}
	cb_info->serv = serv;
	/* As there is only one thread we need to over-ride the
	 * default maximum of 80 connections
	 */
	serv->sv_maxconn = 1024;
	dprintk("nfs_callback_create_svc: service created\n");
	return serv;
}

/*
 * 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;
	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	int ret;
	struct net *net = xprt->xprt_net;

	mutex_lock(&nfs_callback_mutex);

	serv = nfs_callback_create_svc(minorversion);
	if (IS_ERR(serv)) {
		ret = PTR_ERR(serv);
		goto err_create;
	}

	ret = nfs_callback_up_net(minorversion, serv, net, xprt);
	if (ret < 0)
		goto err_net;

	ret = nfs_callback_start_svc(minorversion, xprt, serv);
	if (ret < 0)
		goto err_start;

	cb_info->users++;
	/*
	 * 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.
	 */
err_net:
	if (!cb_info->users)
		cb_info->serv = NULL;
	svc_destroy(serv);
err_create:
	mutex_unlock(&nfs_callback_mutex);
	return ret;

err_start:
	nfs_callback_down_net(minorversion, serv, net);
	dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
	goto err_net;
}

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

	mutex_lock(&nfs_callback_mutex);
	serv = cb_info->serv;
	nfs_callback_down_net(minorversion, serv, net);
	cb_info->users--;
	if (cb_info->users == 0) {
		svc_get(serv);
		serv->sv_ops->svo_setup(serv, NULL, 0);
		svc_destroy(serv);
		dprintk("nfs_callback_down: service destroyed\n");
		cb_info->serv = NULL;
	}
	mutex_unlock(&nfs_callback_mutex);
}

/* Boolean check of RPC_AUTH_GSS principal */
int
check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
{
	char *p = rqstp->rq_cred.cr_principal;

	if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
		return 1;

	/* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
	if (clp->cl_minorversion != 0)
		return 0;
	/*
	 * 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 0;

	/*
	 * Did we get the acceptor from userland during the SETCLIENID
	 * negotiation?
	 */
	if (clp->cl_acceptor)
		return !strcmp(p, clp->cl_acceptor);

	/*
	 * Otherwise try to verify it using the cl_hostname. Note that this
	 * doesn't work if a non-canonical hostname was used in the devname.
	 */

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

	if (memcmp(p, "nfs@", 4) != 0)
		return 0;
	p += 4;
	if (strcmp(p, clp->cl_hostname) != 0)
		return 0;
	return 1;
}

/*
 * pg_authenticate method for nfsv4 callback threads.
 *
 * The authflavor has been negotiated, so an incorrect flavor is a server
 * bug. Deny packets with incorrect authflavor.
 *
 * All other checking done after NFS decoding where the nfs_client can be
 * found in nfs4_callback_compound
 */
static int nfs_callback_authenticate(struct svc_rqst *rqstp)
{
	switch (rqstp->rq_authop->flavour) {
	case RPC_AUTH_NULL:
		if (rqstp->rq_proc != CB_NULL)
			return SVC_DENIED;
		break;
	case RPC_AUTH_GSS:
		/* No RPC_AUTH_GSS support yet in NFSv4.1 */
		 if (svc_is_backchannel(rqstp))
			return SVC_DENIED;
	}
	return SVC_OK;
}

/*
 * 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>
3f07c014	12	#include <linux/sched/signal.h>
1da177e4 LT	13	#include <linux/sunrpc/svc.h>
	14	#include <linux/sunrpc/svcsock.h>
	15	#include <linux/nfs_fs.h>
758201e2	16	#include <linux/errno.h>
353ab6e9	17	#include <linux/mutex.h>
83144186	18	#include <linux/freezer.h>
a277e33c	19	#include <linux/kthread.h>
945b34a7	20	#include <linux/sunrpc/svcauth_gss.h>
a43cde94	21	#include <linux/sunrpc/bc_xprt.h>
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"
bbe0a3aa	28	#include "netns.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;
1da177e4 LT	35	};
1da177e4 LT	36
e82dc22d	37	static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
353ab6e9	38	static DEFINE_MUTEX(nfs_callback_mutex);
1da177e4 LT	39	static struct svc_program nfs4_callback_program;
1da177e4 LT	40
c946556b SK	41	static int nfs4_callback_up_net(struct svc_serv serv, struct net net)
	42	{
	43	int ret;
bbe0a3aa	44	struct nfs_net *nn = net_generic(net, nfs_net_id);
c946556b SK	45
	46	ret = svc_create_xprt(serv, "tcp", net, PF_INET,
	47	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	48	if (ret <= 0)
	49	goto out_err;
bbe0a3aa	50	nn->nfs_callback_tcpport = ret;
c946556b	51	dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
bbe0a3aa	52	nn->nfs_callback_tcpport, PF_INET, net);
c946556b SK	53
	54	ret = svc_create_xprt(serv, "tcp", net, PF_INET6,
	55	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	56	if (ret > 0) {
29dcc16a	57	nn->nfs_callback_tcpport6 = ret;
c946556b	58	dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
29dcc16a	59	nn->nfs_callback_tcpport6, PF_INET6, net);
c946556b SK	60	} else if (ret != -EAFNOSUPPORT)
	61	goto out_err;
	62	return 0;
	63
	64	out_err:
	65	return (ret) ? ret : -ENOMEM;
	66	}
	67
1da177e4	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	{
5b444cc9	74	int err;
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);
5b444cc9	84	if (err == -EAGAIN \|\| err == -EINTR)
1da177e4	85	continue;
6fb2b47f	86	svc_process(rqstp);
1da177e4	87	}
a277e33c	88	return 0;
1da177e4 LT	89	}
1da177e4 LT	90
a43cde94 RL	91	#if defined(CONFIG_NFS_V4_1)
	92	/*
	93	* The callback service for NFSv4.1 callbacks
	94	*/
	95	static int
	96	nfs41_callback_svc(void *vrqstp)
	97	{
	98	struct svc_rqst *rqstp = vrqstp;
	99	struct svc_serv *serv = rqstp->rq_server;
	100	struct rpc_rqst *req;
	101	int error;
	102	DEFINE_WAIT(wq);
	103
	104	set_freezable();
	105
a43cde94	106	while (!kthread_should_stop()) {
25d280aa JL	107	if (try_to_freeze())
	108	continue;
	109
5d05e54a	110	prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
a43cde94 RL	111	spin_lock_bh(&serv->sv_cb_lock);
	112	if (!list_empty(&serv->sv_cb_list)) {
	113	req = list_first_entry(&serv->sv_cb_list,
	114	struct rpc_rqst, rq_bc_list);
	115	list_del(&req->rq_bc_list);
	116	spin_unlock_bh(&serv->sv_cb_lock);
6ffa30d3	117	finish_wait(&serv->sv_cb_waitq, &wq);
a43cde94 RL	118	dprintk("Invoking bc_svc_process()\n");
	119	error = bc_svc_process(serv, req, rqstp);
	120	dprintk("bc_svc_process() returned w/ error code= %d\n",
	121	error);
	122	} else {
	123	spin_unlock_bh(&serv->sv_cb_lock);
5d05e54a	124	schedule();
6ffa30d3	125	finish_wait(&serv->sv_cb_waitq, &wq);
a43cde94	126	}
5d05e54a	127	flush_signals(current);
a43cde94	128	}
a43cde94 RL	129	return 0;
	130	}
	131
a43cde94	132	static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
691c457a	133	struct svc_serv *serv)
a43cde94 RL	134	{
a43cde94 RL	135	if (minorversion)
691c457a SK	136	/*
	137	* Save the svc_serv in the transport so that it can
	138	* be referenced when the session backchannel is initialized
	139	*/
	140	xprt->bc_serv = serv;
a43cde94 RL	141	}
a43cde94 RL	142	#else
a43cde94	143	static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
691c457a	144	struct svc_serv *serv)
a43cde94 RL	145	{
	146	}
	147	#endif /* CONFIG_NFS_V4_1 */
	148
8e246144 SK	149	static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
	150	struct svc_serv *serv)
	151	{
5405fc44	152	int nrservs = nfs_callback_nr_threads;
8e246144	153	int ret;
8e246144 SK	154
	155	nfs_callback_bc_serv(minorversion, xprt, serv);
	156
5405fc44 TM	157	if (nrservs < NFS4_MIN_NR_CALLBACK_THREADS)
	158	nrservs = NFS4_MIN_NR_CALLBACK_THREADS;
	159
bb6aeba7	160	if (serv->sv_nrthreads-1 == nrservs)
23c20ecd SK	161	return 0;
23c20ecd SK	162
bb6aeba7 TM	163	ret = serv->sv_ops->svo_setup(serv, NULL, nrservs);
	164	if (ret) {
	165	serv->sv_ops->svo_setup(serv, NULL, 0);
e9b7e917	166	return ret;
8e246144 SK	167	}
	168	dprintk("nfs_callback_up: service started\n");
	169	return 0;
	170	}
	171
b3d19c51 SK	172	static void nfs_callback_down_net(u32 minorversion, struct svc_serv serv, struct net net)
	173	{
	174	struct nfs_net *nn = net_generic(net, nfs_net_id);
	175
	176	if (--nn->cb_users[minorversion])
	177	return;
	178
	179	dprintk("NFS: destroy per-net callback data; net=%p\n", net);
	180	svc_shutdown_net(serv, net);
	181	}
	182
76566773 CL	183	static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
76566773 CL	184	struct net net, struct rpc_xprt xprt)
c946556b	185	{
b3d19c51	186	struct nfs_net *nn = net_generic(net, nfs_net_id);
c946556b SK	187	int ret;
c946556b SK	188
b3d19c51 SK	189	if (nn->cb_users[minorversion]++)
	190	return 0;
	191
c946556b SK	192	dprintk("NFS: create per-net callback data; net=%p\n", net);
	193
	194	ret = svc_bind(serv, net);
	195	if (ret < 0) {
	196	printk(KERN_WARNING "NFS: bind callback service failed\n");
	197	goto err_bind;
	198	}
	199
76566773	200	ret = -EPROTONOSUPPORT;
d55b352b	201	if (!IS_ENABLED(CONFIG_NFS_V4_1) \|\| minorversion == 0)
76566773 CL	202	ret = nfs4_callback_up_net(serv, net);
	203	else if (xprt->ops->bc_up)
	204	ret = xprt->ops->bc_up(serv, net);
c946556b SK	205
	206	if (ret < 0) {
	207	printk(KERN_ERR "NFS: callback service start failed\n");
	208	goto err_socks;
	209	}
	210	return 0;
	211
	212	err_socks:
	213	svc_rpcb_cleanup(serv, net);
	214	err_bind:
98b0f80c	215	nn->cb_users[minorversion]--;
23c20ecd SK	216	dprintk("NFS: Couldn't create callback socket: err = %d; "
23c20ecd SK	217	"net = %p\n", ret, net);
c946556b SK	218	return ret;
	219	}
	220
f4b52bb0 TM	221	static struct svc_serv_ops nfs40_cb_sv_ops = {
f4b52bb0 TM	222	.svo_function = nfs4_callback_svc,
b9e13cdf	223	.svo_enqueue_xprt = svc_xprt_do_enqueue,
bb6aeba7	224	.svo_setup = svc_set_num_threads,
f4b52bb0 TM	225	.svo_module = THIS_MODULE,
	226	};
	227	#if defined(CONFIG_NFS_V4_1)
	228	static struct svc_serv_ops nfs41_cb_sv_ops = {
	229	.svo_function = nfs41_callback_svc,
	230	.svo_enqueue_xprt = svc_xprt_do_enqueue,
bb6aeba7	231	.svo_setup = svc_set_num_threads,
f4b52bb0	232	.svo_module = THIS_MODULE,
ea126e74 JL	233	};
ea126e74 JL	234
f4b52bb0 TM	235	struct svc_serv_ops *nfs4_cb_sv_ops[] = {
	236	[0] = &nfs40_cb_sv_ops,
	237	[1] = &nfs41_cb_sv_ops,
	238	};
	239	#else
	240	struct svc_serv_ops *nfs4_cb_sv_ops[] = {
	241	[0] = &nfs40_cb_sv_ops,
	242	[1] = NULL,
	243	};
	244	#endif
	245
dd018428 SK	246	static struct svc_serv *nfs_callback_create_svc(int minorversion)
	247	{
	248	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	249	struct svc_serv *serv;
f4b52bb0	250	struct svc_serv_ops *sv_ops;
dd018428 SK	251
	252	/*
	253	* Check whether we're already up and running.
	254	*/
3b01c11e	255	if (cb_info->serv) {
dd018428 SK	256	/*
	257	* Note: increase service usage, because later in case of error
	258	* svc_destroy() will be called.
	259	*/
	260	svc_get(cb_info->serv);
	261	return cb_info->serv;
	262	}
	263
f4b52bb0 TM	264	switch (minorversion) {
	265	case 0:
	266	sv_ops = nfs4_cb_sv_ops[0];
	267	break;
	268	default:
	269	sv_ops = nfs4_cb_sv_ops[1];
	270	}
	271
	272	if (sv_ops == NULL)
	273	return ERR_PTR(-ENOTSUPP);
	274
dd018428 SK	275	/*
	276	* Sanity check: if there's no task,
	277	* we should be the first user ...
	278	*/
	279	if (cb_info->users)
	280	printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
	281	cb_info->users);
	282
f4b52bb0	283	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, sv_ops);
dd018428 SK	284	if (!serv) {
	285	printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
	286	return ERR_PTR(-ENOMEM);
	287	}
3b01c11e	288	cb_info->serv = serv;
dd018428 SK	289	/* As there is only one thread we need to over-ride the
	290	* default maximum of 80 connections
	291	*/
	292	serv->sv_maxconn = 1024;
	293	dprintk("nfs_callback_create_svc: service created\n");
	294	return serv;
	295	}
	296
71468513 BH	297	/*
	298	* Bring up the callback thread if it is not already up.
	299	*/
	300	int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
	301	{
dd018428	302	struct svc_serv *serv;
e82dc22d	303	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
23c20ecd	304	int ret;
c946556b	305	struct net *net = xprt->xprt_net;
71468513 BH	306
71468513 BH	307	mutex_lock(&nfs_callback_mutex);
dd018428 SK	308
	309	serv = nfs_callback_create_svc(minorversion);
	310	if (IS_ERR(serv)) {
	311	ret = PTR_ERR(serv);
	312	goto err_create;
	313	}
	314
76566773	315	ret = nfs_callback_up_net(minorversion, serv, net, xprt);
c946556b SK	316	if (ret < 0)
c946556b SK	317	goto err_net;
9793f7c8	318
8e246144 SK	319	ret = nfs_callback_start_svc(minorversion, xprt, serv);
	320	if (ret < 0)
	321	goto err_start;
a277e33c	322
23c20ecd	323	cb_info->users++;
8e60029f JL	324	/*
8e60029f JL	325	* svc_create creates the svc_serv with sv_nrthreads == 1, and then
a277e33c	326	* svc_prepare_thread increments that. So we need to call svc_destroy
8e60029f JL	327	* on both success and failure so that the refcount is 1 when the
	328	* thread exits.
	329	*/
23c20ecd	330	err_net:
3b01c11e TM	331	if (!cb_info->users)
3b01c11e TM	332	cb_info->serv = NULL;
dd018428 SK	333	svc_destroy(serv);
dd018428 SK	334	err_create:
353ab6e9	335	mutex_unlock(&nfs_callback_mutex);
1da177e4	336	return ret;
8e246144 SK	337
8e246144 SK	338	err_start:
b3d19c51	339	nfs_callback_down_net(minorversion, serv, net);
23c20ecd SK	340	dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
23c20ecd SK	341	goto err_net;
1da177e4 LT	342	}
	343
	344	/*
5afc597c	345	* Kill the callback thread if it's no longer being used.
1da177e4	346	*/
c8ceb412	347	void nfs_callback_down(int minorversion, struct net *net)
1da177e4	348	{
e82dc22d	349	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
bb6aeba7	350	struct svc_serv *serv;
e82dc22d	351
353ab6e9	352	mutex_lock(&nfs_callback_mutex);
bb6aeba7 TM	353	serv = cb_info->serv;
bb6aeba7 TM	354	nfs_callback_down_net(minorversion, serv, net);
e82dc22d	355	cb_info->users--;
3b01c11e	356	if (cb_info->users == 0) {
bb6aeba7 TM	357	svc_get(serv);
	358	serv->sv_ops->svo_setup(serv, NULL, 0);
	359	svc_destroy(serv);
1dc42e04	360	dprintk("nfs_callback_down: service destroyed\n");
e82dc22d	361	cb_info->serv = NULL;
5afc597c	362	}
353ab6e9	363	mutex_unlock(&nfs_callback_mutex);
1da177e4 LT	364	}
1da177e4 LT	365
778be232 AA	366	/* Boolean check of RPC_AUTH_GSS principal */
	367	int
	368	check_gss_callback_principal(struct nfs_client clp, struct svc_rqst rqstp)
945b34a7	369	{
03a4e1f6	370	char *p = rqstp->rq_cred.cr_principal;
945b34a7	371
778be232 AA	372	if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
	373	return 1;
	374
ece0de63 AA	375	/* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
ece0de63 AA	376	if (clp->cl_minorversion != 0)
778be232	377	return 0;
945b34a7 OK	378	/*
	379	* It might just be a normal user principal, in which case
	380	* userspace won't bother to tell us the name at all.
	381	*/
	382	if (p == NULL)
778be232	383	return 0;
945b34a7	384
f11b2a1c JL	385	/*
	386	* Did we get the acceptor from userland during the SETCLIENID
	387	* negotiation?
	388	*/
	389	if (clp->cl_acceptor)
	390	return !strcmp(p, clp->cl_acceptor);
	391
	392	/*
	393	* Otherwise try to verify it using the cl_hostname. Note that this
	394	* doesn't work if a non-canonical hostname was used in the devname.
	395	*/
	396
945b34a7 OK	397	/* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
	398
	399	if (memcmp(p, "nfs@", 4) != 0)
778be232	400	return 0;
945b34a7	401	p += 4;
4e0038b6	402	if (strcmp(p, clp->cl_hostname) != 0)
778be232 AA	403	return 0;
778be232 AA	404	return 1;
945b34a7 OK	405	}
945b34a7 OK	406
778be232 AA	407	/*
	408	* pg_authenticate method for nfsv4 callback threads.
	409	*
	410	* The authflavor has been negotiated, so an incorrect flavor is a server
6f02dc88	411	* bug. Deny packets with incorrect authflavor.
778be232 AA	412	*
	413	* All other checking done after NFS decoding where the nfs_client can be
	414	* found in nfs4_callback_compound
	415	*/
1da177e4 LT	416	static int nfs_callback_authenticate(struct svc_rqst *rqstp)
1da177e4 LT	417	{
1da177e4	418	switch (rqstp->rq_authop->flavour) {
778be232 AA	419	case RPC_AUTH_NULL:
778be232 AA	420	if (rqstp->rq_proc != CB_NULL)
6f02dc88	421	return SVC_DENIED;
778be232 AA	422	break;
	423	case RPC_AUTH_GSS:
	424	/* No RPC_AUTH_GSS support yet in NFSv4.1 */
	425	if (svc_is_backchannel(rqstp))
6f02dc88	426	return SVC_DENIED;
1da177e4	427	}
778be232	428	return SVC_OK;
1da177e4 LT	429	}
	430
	431	/*
	432	* Define NFS4 callback program
	433	*/
1da177e4 LT	434	static struct svc_version *nfs4_callback_version[] = {
1da177e4 LT	435	[1] = &nfs4_callback_version1,
07bccc2d	436	[4] = &nfs4_callback_version4,
1da177e4 LT	437	};
	438
	439	static struct svc_stat nfs4_callback_stats;
	440
	441	static struct svc_program nfs4_callback_program = {
	442	.pg_prog = NFS4_CALLBACK, /* RPC service number */
	443	.pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
	444	.pg_vers = nfs4_callback_version, /* version table */
	445	.pg_name = "NFSv4 callback", /* service name */
	446	.pg_class = "nfs", /* authentication class */
	447	.pg_stats = &nfs4_callback_stats,
	448	.pg_authenticate = nfs_callback_authenticate,
	449	};