[linux-2.6-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>

#include <net/inet_sock.h>

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

#define NFSDBG_FACILITY NFSDBG_CALLBACK

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

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

unsigned int nfs_callback_set_tcpport;
unsigned short nfs_callback_tcpport;
unsigned short nfs_callback_tcpport6;
static const int nfs_set_port_min = 0;
static const int nfs_set_port_max = 65535;

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

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

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

	set_freezable();

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

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

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

	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)
		goto out_err;
#endif	/* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */

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

	svc_sock_update_bufs(serv);

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

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

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

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

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

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

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

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

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

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

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

static struct svc_stat nfs4_callback_stats;

static struct svc_program nfs4_callback_program = {
	.pg_prog = NFS4_CALLBACK,			/* RPC service number */
	.pg_nvers = ARRAY_SIZE(nfs4_callback_version),	/* Number of entries */
	.pg_vers = nfs4_callback_version,		/* version table */
	.pg_name = "NFSv4 callback",			/* service name */
	.pg_class = "nfs",				/* authentication class */
	.pg_stats = &nfs4_callback_stats,
	.pg_authenticate = nfs_callback_authenticate,
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/nfs/callback.c
	3	*
	4	* Copyright (C) 2004 Trond Myklebust
	5	*
	6	* NFSv4 callback handling
	7	*/
	8
1da177e4 LT	9	#include <linux/completion.h>
	10	#include <linux/ip.h>
	11	#include <linux/module.h>
	12	#include <linux/smp_lock.h>
	13	#include <linux/sunrpc/svc.h>
	14	#include <linux/sunrpc/svcsock.h>
	15	#include <linux/nfs_fs.h>
353ab6e9	16	#include <linux/mutex.h>
83144186	17	#include <linux/freezer.h>
a277e33c	18	#include <linux/kthread.h>
945b34a7	19	#include <linux/sunrpc/svcauth_gss.h>
14c85021 ACM	20
	21	#include <net/inet_sock.h>
	22
4ce79717	23	#include "nfs4_fs.h"
1da177e4	24	#include "callback.h"
24c8dbbb	25	#include "internal.h"
1da177e4 LT	26
	27	#define NFSDBG_FACILITY NFSDBG_CALLBACK
	28
	29	struct nfs_callback_data {
	30	unsigned int users;
5afc597c	31	struct svc_rqst *rqst;
a277e33c	32	struct task_struct *task;
1da177e4 LT	33	};
	34
	35	static struct nfs_callback_data nfs_callback_info;
353ab6e9	36	static DEFINE_MUTEX(nfs_callback_mutex);
1da177e4 LT	37	static struct svc_program nfs4_callback_program;
1da177e4 LT	38
a72b4422	39	unsigned int nfs_callback_set_tcpport;
1da177e4	40	unsigned short nfs_callback_tcpport;
f738f517	41	unsigned short nfs_callback_tcpport6;
7d4e2747 DH	42	static const int nfs_set_port_min = 0;
	43	static const int nfs_set_port_max = 65535;
	44
	45	static int param_set_port(const char val, struct kernel_param kp)
	46	{
	47	char *endp;
	48	int num = simple_strtol(val, &endp, 0);
	49	if (endp == val \|\| *endp \|\| num < nfs_set_port_min \|\| num > nfs_set_port_max)
	50	return -EINVAL;
	51	((int )kp->arg) = num;
	52	return 0;
	53	}
	54
	55	module_param_call(callback_tcpport, param_set_port, param_get_int,
	56	&nfs_callback_set_tcpport, 0644);
1da177e4 LT	57
	58	/*
	59	* This is the callback kernel thread.
	60	*/
a277e33c JL	61	static int
a277e33c JL	62	nfs_callback_svc(void *vrqstp)
1da177e4	63	{
06e02d66	64	int err, preverr = 0;
a277e33c	65	struct svc_rqst *rqstp = vrqstp;
1da177e4	66
83144186	67	set_freezable();
1da177e4	68
a277e33c JL	69	/*
	70	* FIXME: do we really need to run this under the BKL? If so, please
	71	* add a comment about what it's intended to protect.
	72	*/
	73	lock_kernel();
	74	while (!kthread_should_stop()) {
1da177e4 LT	75	/*
	76	* Listen for a request on the socket
	77	*/
6fb2b47f	78	err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
06e02d66 JL	79	if (err == -EAGAIN \|\| err == -EINTR) {
06e02d66 JL	80	preverr = err;
1da177e4	81	continue;
06e02d66	82	}
1da177e4	83	if (err < 0) {
06e02d66 JL	84	if (err != preverr) {
	85	printk(KERN_WARNING "%s: unexpected error "
	86	"from svc_recv (%d)\n", __func__, err);
	87	preverr = err;
	88	}
	89	schedule_timeout_uninterruptible(HZ);
	90	continue;
1da177e4	91	}
06e02d66	92	preverr = err;
6fb2b47f	93	svc_process(rqstp);
1da177e4	94	}
1da177e4	95	unlock_kernel();
a277e33c	96	return 0;
1da177e4 LT	97	}
	98
	99	/*
5afc597c	100	* Bring up the callback thread if it is not already up.
1da177e4 LT	101	*/
	102	int nfs_callback_up(void)
	103	{
8e60029f	104	struct svc_serv *serv = NULL;
1da177e4 LT	105	int ret = 0;
1da177e4 LT	106
353ab6e9	107	mutex_lock(&nfs_callback_mutex);
a277e33c	108	if (nfs_callback_info.users++ \|\| nfs_callback_info.task != NULL)
1da177e4	109	goto out;
49a9072f	110	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
1da177e4 LT	111	ret = -ENOMEM;
	112	if (!serv)
	113	goto out_err;
482fb94e	114
26298caa	115	ret = svc_create_xprt(serv, "tcp", PF_INET,
9652ada3	116	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
482fb94e	117	if (ret <= 0)
8e60029f	118	goto out_err;
482fb94e	119	nfs_callback_tcpport = ret;
18de9735	120	dprintk("NFS: Callback listener port = %u (af %u)\n",
26298caa	121	nfs_callback_tcpport, PF_INET);
482fb94e	122
f738f517 CL	123	#if defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE)
	124	ret = svc_create_xprt(serv, "tcp", PF_INET6,
	125	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	126	if (ret > 0) {
	127	nfs_callback_tcpport6 = ret;
	128	dprintk("NFS: Callback listener port = %u (af %u)\n",
	129	nfs_callback_tcpport6, PF_INET6);
	130	} else if (ret != -EAFNOSUPPORT)
	131	goto out_err;
	132	#endif /* defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE) */
	133
5afc597c JL	134	nfs_callback_info.rqst = svc_prepare_thread(serv, &serv->sv_pools[0]);
	135	if (IS_ERR(nfs_callback_info.rqst)) {
	136	ret = PTR_ERR(nfs_callback_info.rqst);
	137	nfs_callback_info.rqst = NULL;
8e60029f	138	goto out_err;
a277e33c JL	139	}
	140
	141	svc_sock_update_bufs(serv);
a277e33c	142
5afc597c JL	143	nfs_callback_info.task = kthread_run(nfs_callback_svc,
5afc597c JL	144	nfs_callback_info.rqst,
a277e33c JL	145	"nfsv4-svc");
	146	if (IS_ERR(nfs_callback_info.task)) {
	147	ret = PTR_ERR(nfs_callback_info.task);
5afc597c JL	148	svc_exit_thread(nfs_callback_info.rqst);
5afc597c JL	149	nfs_callback_info.rqst = NULL;
a277e33c	150	nfs_callback_info.task = NULL;
a277e33c JL	151	goto out_err;
a277e33c JL	152	}
1da177e4	153	out:
8e60029f JL	154	/*
8e60029f JL	155	* svc_create creates the svc_serv with sv_nrthreads == 1, and then
a277e33c	156	* svc_prepare_thread increments that. So we need to call svc_destroy
8e60029f JL	157	* on both success and failure so that the refcount is 1 when the
	158	* thread exits.
	159	*/
	160	if (serv)
	161	svc_destroy(serv);
353ab6e9	162	mutex_unlock(&nfs_callback_mutex);
1da177e4	163	return ret;
8e60029f	164	out_err:
18de9735 CL	165	dprintk("NFS: Couldn't create callback socket or server thread; "
18de9735 CL	166	"err = %d\n", ret);
1da177e4 LT	167	nfs_callback_info.users--;
	168	goto out;
	169	}
	170
	171	/*
5afc597c	172	* Kill the callback thread if it's no longer being used.
1da177e4	173	*/
5ae1fbce	174	void nfs_callback_down(void)
1da177e4	175	{
353ab6e9	176	mutex_lock(&nfs_callback_mutex);
1dd761e9	177	nfs_callback_info.users--;
5afc597c	178	if (nfs_callback_info.users == 0 && nfs_callback_info.task != NULL) {
a277e33c	179	kthread_stop(nfs_callback_info.task);
5afc597c JL	180	svc_exit_thread(nfs_callback_info.rqst);
	181	nfs_callback_info.rqst = NULL;
	182	nfs_callback_info.task = NULL;
	183	}
353ab6e9	184	mutex_unlock(&nfs_callback_mutex);
1da177e4 LT	185	}
1da177e4 LT	186
945b34a7 OK	187	static int check_gss_callback_principal(struct nfs_client *clp,
	188	struct svc_rqst *rqstp)
	189	{
	190	struct rpc_clnt *r = clp->cl_rpcclient;
	191	char *p = svc_gss_principal(rqstp);
	192
	193	/*
	194	* It might just be a normal user principal, in which case
	195	* userspace won't bother to tell us the name at all.
	196	*/
	197	if (p == NULL)
	198	return SVC_DENIED;
	199
	200	/* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
	201
	202	if (memcmp(p, "nfs@", 4) != 0)
	203	return SVC_DENIED;
	204	p += 4;
	205	if (strcmp(p, r->cl_server) != 0)
	206	return SVC_DENIED;
	207	return SVC_OK;
	208	}
	209
1da177e4 LT	210	static int nfs_callback_authenticate(struct svc_rqst *rqstp)
1da177e4 LT	211	{
adfa6f98	212	struct nfs_client *clp;
5216a8e7	213	RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
945b34a7	214	int ret = SVC_OK;
1da177e4 LT	215
1da177e4 LT	216	/* Don't talk to strangers */
ff052645	217	clp = nfs_find_client(svc_addr(rqstp), 4);
1da177e4 LT	218	if (clp == NULL)
1da177e4 LT	219	return SVC_DROP;
ad06e4bd	220
3110ff80	221	dprintk("%s: %s NFSv4 callback!\n", __func__,
ad06e4bd	222	svc_print_addr(rqstp, buf, sizeof(buf)));
ad06e4bd	223
1da177e4 LT	224	switch (rqstp->rq_authop->flavour) {
	225	case RPC_AUTH_NULL:
	226	if (rqstp->rq_proc != CB_NULL)
945b34a7	227	ret = SVC_DENIED;
1da177e4 LT	228	break;
	229	case RPC_AUTH_UNIX:
	230	break;
	231	case RPC_AUTH_GSS:
945b34a7 OK	232	ret = check_gss_callback_principal(clp, rqstp);
945b34a7 OK	233	break;
1da177e4	234	default:
945b34a7	235	ret = SVC_DENIED;
1da177e4	236	}
945b34a7 OK	237	nfs_put_client(clp);
945b34a7 OK	238	return ret;
1da177e4 LT	239	}
	240
	241	/*
	242	* Define NFS4 callback program
	243	*/
1da177e4 LT	244	static struct svc_version *nfs4_callback_version[] = {
	245	[1] = &nfs4_callback_version1,
	246	};
	247
	248	static struct svc_stat nfs4_callback_stats;
	249
	250	static struct svc_program nfs4_callback_program = {
	251	.pg_prog = NFS4_CALLBACK, /* RPC service number */
	252	.pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
	253	.pg_vers = nfs4_callback_version, /* version table */
	254	.pg_name = "NFSv4 callback", /* service name */
	255	.pg_class = "nfs", /* authentication class */
	256	.pg_stats = &nfs4_callback_stats,
	257	.pg_authenticate = nfs_callback_authenticate,
	258	};