linux/fs/nfs/callback.c
Benny Halevy 8f97524235 nfs41: create a svc_xprt for nfs41 callback thread and use for incoming callbacks
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17 14:11:31 -07:00

405 lines
9.8 KiB
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;
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
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)
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();
nfs_callback_info.task = NULL;
svc_exit_thread(rqstp);
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);
char svc_name[12];
int ret = 0;
int minorversion_setup;
mutex_lock(&nfs_callback_mutex);
if (nfs_callback_info.users++ || nfs_callback_info.task != NULL) {
nfs_callback_bc_serv(minorversion, xprt, &nfs_callback_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);
nfs_callback_info.serv = serv;
nfs_callback_info.rqst = rqstp;
nfs_callback_info.task = kthread_run(callback_svc,
nfs_callback_info.rqst,
svc_name);
if (IS_ERR(nfs_callback_info.task)) {
ret = PTR_ERR(nfs_callback_info.task);
svc_exit_thread(nfs_callback_info.rqst);
nfs_callback_info.serv = NULL;
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.serv = NULL;
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,
};