[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/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 <linux/sunrpc/bc_xprt.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_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 "NFS: %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
 */
static struct svc_rqst *
nfs4_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
{
	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], NUMA_NO_NODE);

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
 */
static struct svc_rqst *
nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
{
	struct svc_rqst *rqstp;
	int ret;

	/*
	 * Create an svc_sock for the back channel service that shares the
	 * fore channel connection.
	 * Returns the input port (0) and sets the svc_serv bc_xprt on success
	 */
	ret = svc_create_xprt(serv, "tcp-bc", &init_net, PF_INET, 0,
			      SVC_SOCK_ANONYMOUS);
	if (ret < 0) {
		rqstp = ERR_PTR(ret);
		goto out;
	}

	/*
	 * Save the svc_serv in the transport so that it can
	 * be referenced when the session backchannel is initialized
	 */
	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], NUMA_NO_NODE);
	if (IS_ERR(rqstp)) {
		svc_xprt_put(serv->sv_bc_xprt);
		serv->sv_bc_xprt = NULL;
	}
out:
	dprintk("--> %s return %ld\n", __func__,
		IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0);
	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;
	struct net *net = &init_net;

	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;
	}

	ret = svc_bind(serv, net);
	if (ret < 0) {
		printk(KERN_WARNING "NFS: bind callback service failed\n");
		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, xprt);
		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--;
	if (serv)
		svc_shutdown_net(serv, net);
	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_shutdown_net(cb_info->serv, &init_net);
		svc_exit_thread(cb_info->rqst);
		cb_info->serv = NULL;
		cb_info->rqst = NULL;
		cb_info->task = 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;

	/* 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. Drop 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_DROP;
		break;
	case RPC_AUTH_GSS:
		/* No RPC_AUTH_GSS support yet in NFSv4.1 */
		 if (svc_is_backchannel(rqstp))
			return SVC_DROP;
	}
	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>
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	19	#include <linux/sunrpc/bc_xprt.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;
a43cde94	31	struct svc_serv *serv;
5afc597c	32	struct svc_rqst *rqst;
a277e33c	33	struct task_struct *task;
1da177e4 LT	34	};
1da177e4 LT	35
e82dc22d	36	static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
353ab6e9	37	static DEFINE_MUTEX(nfs_callback_mutex);
1da177e4 LT	38	static struct svc_program nfs4_callback_program;
1da177e4 LT	39
a72b4422	40	unsigned int nfs_callback_set_tcpport;
1da177e4	41	unsigned short nfs_callback_tcpport;
f738f517	42	unsigned short nfs_callback_tcpport6;
c140aa91	43	#define NFS_CALLBACK_MAXPORTNR (65535U)
7d4e2747	44
9bbb9e5a	45	static int param_set_portnr(const char val, const struct kernel_param kp)
7d4e2747	46	{
c140aa91 TM	47	unsigned long num;
	48	int ret;
	49
	50	if (!val)
	51	return -EINVAL;
	52	ret = strict_strtoul(val, 0, &num);
	53	if (ret == -EINVAL \|\| num > NFS_CALLBACK_MAXPORTNR)
7d4e2747	54	return -EINVAL;
c140aa91	55	((unsigned int )kp->arg) = num;
7d4e2747 DH	56	return 0;
7d4e2747 DH	57	}
9bbb9e5a RR	58	static struct kernel_param_ops param_ops_portnr = {
	59	.set = param_set_portnr,
	60	.get = param_get_uint,
	61	};
c140aa91 TM	62	#define param_check_portnr(name, p) __param_check(name, p, unsigned int);
	63
	64	module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
1da177e4 LT	65
1da177e4 LT	66	/*
e82dc22d	67	* This is the NFSv4 callback kernel thread.
1da177e4	68	*/
a277e33c	69	static int
71468513	70	nfs4_callback_svc(void *vrqstp)
1da177e4	71	{
06e02d66	72	int err, preverr = 0;
a277e33c	73	struct svc_rqst *rqstp = vrqstp;
1da177e4	74
83144186	75	set_freezable();
1da177e4	76
a277e33c	77	while (!kthread_should_stop()) {
1da177e4 LT	78	/*
	79	* Listen for a request on the socket
	80	*/
6fb2b47f	81	err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
06e02d66 JL	82	if (err == -EAGAIN \|\| err == -EINTR) {
06e02d66 JL	83	preverr = err;
1da177e4	84	continue;
06e02d66	85	}
1da177e4	86	if (err < 0) {
06e02d66	87	if (err != preverr) {
a030889a	88	printk(KERN_WARNING "NFS: %s: unexpected error "
06e02d66 JL	89	"from svc_recv (%d)\n", __func__, err);
	90	preverr = err;
	91	}
	92	schedule_timeout_uninterruptible(HZ);
	93	continue;
1da177e4	94	}
06e02d66	95	preverr = err;
6fb2b47f	96	svc_process(rqstp);
1da177e4	97	}
a277e33c	98	return 0;
1da177e4 LT	99	}
	100
	101	/*
71468513	102	* Prepare to bring up the NFSv4 callback service
1da177e4	103	*/
17280175	104	static struct svc_rqst *
7bb782c6	105	nfs4_callback_up(struct svc_serv serv, struct rpc_xprt xprt)
1da177e4	106	{
71468513	107	int ret;
482fb94e	108
12918b10	109	ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET,
9652ada3	110	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
482fb94e	111	if (ret <= 0)
8e60029f	112	goto out_err;
482fb94e	113	nfs_callback_tcpport = ret;
18de9735	114	dprintk("NFS: Callback listener port = %u (af %u)\n",
26298caa	115	nfs_callback_tcpport, PF_INET);
482fb94e	116
12918b10	117	ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET6,
f738f517 CL	118	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	119	if (ret > 0) {
	120	nfs_callback_tcpport6 = ret;
	121	dprintk("NFS: Callback listener port = %u (af %u)\n",
	122	nfs_callback_tcpport6, PF_INET6);
18fc3164 CL	123	} else if (ret == -EAFNOSUPPORT)
	124	ret = 0;
	125	else
f738f517	126	goto out_err;
f738f517	127
11fd165c	128	return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
71468513 BH	129
	130	out_err:
	131	if (ret == 0)
	132	ret = -ENOMEM;
	133	return ERR_PTR(ret);
	134	}
	135
a43cde94 RL	136	#if defined(CONFIG_NFS_V4_1)
	137	/*
	138	* The callback service for NFSv4.1 callbacks
	139	*/
	140	static int
	141	nfs41_callback_svc(void *vrqstp)
	142	{
	143	struct svc_rqst *rqstp = vrqstp;
	144	struct svc_serv *serv = rqstp->rq_server;
	145	struct rpc_rqst *req;
	146	int error;
	147	DEFINE_WAIT(wq);
	148
	149	set_freezable();
	150
a43cde94 RL	151	while (!kthread_should_stop()) {
	152	prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
	153	spin_lock_bh(&serv->sv_cb_lock);
	154	if (!list_empty(&serv->sv_cb_list)) {
	155	req = list_first_entry(&serv->sv_cb_list,
	156	struct rpc_rqst, rq_bc_list);
	157	list_del(&req->rq_bc_list);
	158	spin_unlock_bh(&serv->sv_cb_lock);
	159	dprintk("Invoking bc_svc_process()\n");
	160	error = bc_svc_process(serv, req, rqstp);
	161	dprintk("bc_svc_process() returned w/ error code= %d\n",
	162	error);
	163	} else {
	164	spin_unlock_bh(&serv->sv_cb_lock);
	165	schedule();
	166	}
	167	finish_wait(&serv->sv_cb_waitq, &wq);
	168	}
a43cde94 RL	169	return 0;
	170	}
	171
	172	/*
	173	* Bring up the NFSv4.1 callback service
	174	*/
17280175	175	static struct svc_rqst *
a43cde94 RL	176	nfs41_callback_up(struct svc_serv serv, struct rpc_xprt xprt)
a43cde94 RL	177	{
01c9a0bc AA	178	struct svc_rqst *rqstp;
01c9a0bc AA	179	int ret;
8f975242	180
01c9a0bc AA	181	/*
	182	* Create an svc_sock for the back channel service that shares the
	183	* fore channel connection.
	184	* Returns the input port (0) and sets the svc_serv bc_xprt on success
	185	*/
12918b10	186	ret = svc_create_xprt(serv, "tcp-bc", &init_net, PF_INET, 0,
01c9a0bc AA	187	SVC_SOCK_ANONYMOUS);
	188	if (ret < 0) {
	189	rqstp = ERR_PTR(ret);
8f975242	190	goto out;
01c9a0bc	191	}
8f975242	192
a43cde94 RL	193	/*
	194	* Save the svc_serv in the transport so that it can
	195	* be referenced when the session backchannel is initialized
	196	*/
	197	xprt->bc_serv = serv;
	198
	199	INIT_LIST_HEAD(&serv->sv_cb_list);
	200	spin_lock_init(&serv->sv_cb_lock);
	201	init_waitqueue_head(&serv->sv_cb_waitq);
11fd165c	202	rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
01c9a0bc	203	if (IS_ERR(rqstp)) {
4a19de0f AA	204	svc_xprt_put(serv->sv_bc_xprt);
4a19de0f AA	205	serv->sv_bc_xprt = NULL;
01c9a0bc	206	}
8f975242	207	out:
01c9a0bc AA	208	dprintk("--> %s return %ld\n", __func__,
01c9a0bc AA	209	IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0);
8f975242	210	return rqstp;
a43cde94 RL	211	}
	212
	213	static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
	214	struct svc_serv serv, struct rpc_xprt xprt,
	215	struct svc_rqst rqstpp, int (callback_svc)(void *vrqstp))
	216	{
	217	if (minorversion) {
	218	*rqstpp = nfs41_callback_up(serv, xprt);
	219	*callback_svc = nfs41_callback_svc;
	220	}
	221	return minorversion;
	222	}
	223
	224	static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
	225	struct nfs_callback_data *cb_info)
	226	{
	227	if (minorversion)
	228	xprt->bc_serv = cb_info->serv;
	229	}
	230	#else
	231	static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
	232	struct svc_serv serv, struct rpc_xprt xprt,
	233	struct svc_rqst rqstpp, int (callback_svc)(void *vrqstp))
	234	{
	235	return 0;
	236	}
	237
	238	static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
	239	struct nfs_callback_data *cb_info)
	240	{
	241	}
	242	#endif /* CONFIG_NFS_V4_1 */
	243
71468513 BH	244	/*
	245	* Bring up the callback thread if it is not already up.
	246	*/
	247	int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
	248	{
	249	struct svc_serv *serv = NULL;
	250	struct svc_rqst *rqstp;
	251	int (callback_svc)(void vrqstp);
e82dc22d	252	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
71468513 BH	253	char svc_name[12];
71468513 BH	254	int ret = 0;
a43cde94	255	int minorversion_setup;
12918b10	256	struct net *net = &init_net;
71468513 BH	257
71468513 BH	258	mutex_lock(&nfs_callback_mutex);
e82dc22d AA	259	if (cb_info->users++ \|\| cb_info->task != NULL) {
e82dc22d AA	260	nfs_callback_bc_serv(minorversion, xprt, cb_info);
71468513	261	goto out;
a43cde94	262	}
71468513 BH	263	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
	264	if (!serv) {
	265	ret = -ENOMEM;
	266	goto out_err;
	267	}
	268
9793f7c8 SK	269	ret = svc_bind(serv, net);
	270	if (ret < 0) {
	271	printk(KERN_WARNING "NFS: bind callback service failed\n");
	272	goto out_err;
	273	}
	274
a43cde94 RL	275	minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion,
	276	serv, xprt, &rqstp, &callback_svc);
	277	if (!minorversion_setup) {
	278	/* v4.0 callback setup */
7bb782c6	279	rqstp = nfs4_callback_up(serv, xprt);
71468513	280	callback_svc = nfs4_callback_svc;
71468513 BH	281	}
	282
	283	if (IS_ERR(rqstp)) {
	284	ret = PTR_ERR(rqstp);
8e60029f	285	goto out_err;
a277e33c JL	286	}
	287
	288	svc_sock_update_bufs(serv);
a277e33c	289
71468513	290	sprintf(svc_name, "nfsv4.%u-svc", minorversion);
e82dc22d AA	291	cb_info->serv = serv;
	292	cb_info->rqst = rqstp;
	293	cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
	294	if (IS_ERR(cb_info->task)) {
	295	ret = PTR_ERR(cb_info->task);
	296	svc_exit_thread(cb_info->rqst);
	297	cb_info->rqst = NULL;
	298	cb_info->task = NULL;
a277e33c JL	299	goto out_err;
a277e33c JL	300	}
1da177e4	301	out:
8e60029f JL	302	/*
8e60029f JL	303	* svc_create creates the svc_serv with sv_nrthreads == 1, and then
a277e33c	304	* svc_prepare_thread increments that. So we need to call svc_destroy
8e60029f JL	305	* on both success and failure so that the refcount is 1 when the
	306	* thread exits.
	307	*/
	308	if (serv)
	309	svc_destroy(serv);
353ab6e9	310	mutex_unlock(&nfs_callback_mutex);
1da177e4	311	return ret;
8e60029f	312	out_err:
18de9735 CL	313	dprintk("NFS: Couldn't create callback socket or server thread; "
18de9735 CL	314	"err = %d\n", ret);
e82dc22d	315	cb_info->users--;
786185b5 SK	316	if (serv)
786185b5 SK	317	svc_shutdown_net(serv, net);
1da177e4 LT	318	goto out;
	319	}
	320
	321	/*
5afc597c	322	* Kill the callback thread if it's no longer being used.
1da177e4	323	*/
e82dc22d	324	void nfs_callback_down(int minorversion)
1da177e4	325	{
e82dc22d AA	326	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
e82dc22d AA	327
353ab6e9	328	mutex_lock(&nfs_callback_mutex);
e82dc22d AA	329	cb_info->users--;
	330	if (cb_info->users == 0 && cb_info->task != NULL) {
	331	kthread_stop(cb_info->task);
12918b10	332	svc_shutdown_net(cb_info->serv, &init_net);
e82dc22d AA	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
778be232 AA	341	/* Boolean check of RPC_AUTH_GSS principal */
	342	int
	343	check_gss_callback_principal(struct nfs_client clp, struct svc_rqst rqstp)
945b34a7	344	{
03a4e1f6	345	char *p = rqstp->rq_cred.cr_principal;
945b34a7	346
778be232 AA	347	if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
	348	return 1;
	349
ece0de63 AA	350	/* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
ece0de63 AA	351	if (clp->cl_minorversion != 0)
778be232	352	return 0;
945b34a7 OK	353	/*
	354	* It might just be a normal user principal, in which case
	355	* userspace won't bother to tell us the name at all.
	356	*/
	357	if (p == NULL)
778be232	358	return 0;
945b34a7 OK	359
	360	/* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
	361
	362	if (memcmp(p, "nfs@", 4) != 0)
778be232	363	return 0;
945b34a7	364	p += 4;
4e0038b6	365	if (strcmp(p, clp->cl_hostname) != 0)
778be232 AA	366	return 0;
778be232 AA	367	return 1;
945b34a7 OK	368	}
945b34a7 OK	369
778be232 AA	370	/*
	371	* pg_authenticate method for nfsv4 callback threads.
	372	*
	373	* The authflavor has been negotiated, so an incorrect flavor is a server
	374	* bug. Drop packets with incorrect authflavor.
	375	*
	376	* All other checking done after NFS decoding where the nfs_client can be
	377	* found in nfs4_callback_compound
	378	*/
1da177e4 LT	379	static int nfs_callback_authenticate(struct svc_rqst *rqstp)
1da177e4 LT	380	{
1da177e4	381	switch (rqstp->rq_authop->flavour) {
778be232 AA	382	case RPC_AUTH_NULL:
	383	if (rqstp->rq_proc != CB_NULL)
	384	return SVC_DROP;
	385	break;
	386	case RPC_AUTH_GSS:
	387	/* No RPC_AUTH_GSS support yet in NFSv4.1 */
	388	if (svc_is_backchannel(rqstp))
	389	return SVC_DROP;
1da177e4	390	}
778be232	391	return SVC_OK;
1da177e4 LT	392	}
	393
	394	/*
	395	* Define NFS4 callback program
	396	*/
1da177e4 LT	397	static struct svc_version *nfs4_callback_version[] = {
1da177e4 LT	398	[1] = &nfs4_callback_version1,
07bccc2d	399	[4] = &nfs4_callback_version4,
1da177e4 LT	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	};