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/*
* 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;
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);
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,
};
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