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/*
* linux/fs/lockd/mon.c
*
* The kernel statd client.
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/types.h>
#include <linux/utsname.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/slab.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/xprtsock.h>
#include <linux/sunrpc/svc.h>
#include <linux/lockd/lockd.h>
#include <asm/unaligned.h>
#define NLMDBG_FACILITY NLMDBG_MONITOR
#define NSM_PROGRAM 100024
#define NSM_VERSION 1
enum {
NSMPROC_NULL,
NSMPROC_STAT,
NSMPROC_MON,
NSMPROC_UNMON,
NSMPROC_UNMON_ALL,
NSMPROC_SIMU_CRASH,
NSMPROC_NOTIFY,
};
struct nsm_args {
struct nsm_private *priv;
u32 prog; /* RPC callback info */
u32 vers;
u32 proc;
char *mon_name;
};
struct nsm_res {
u32 status;
u32 state;
};
static struct rpc_program nsm_program;
static LIST_HEAD(nsm_handles);
static DEFINE_SPINLOCK(nsm_lock);
/*
* Local NSM state
*/
u32 __read_mostly nsm_local_state;
int __read_mostly nsm_use_hostnames;
static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm)
{
return (struct sockaddr *)&nsm->sm_addr;
}
static struct rpc_clnt *nsm_create(void)
{
struct sockaddr_in sin = {
.sin_family = AF_INET,
.sin_addr.s_addr = htonl(INADDR_LOOPBACK),
};
struct rpc_create_args args = {
.protocol = XPRT_TRANSPORT_UDP,
.address = (struct sockaddr *)&sin,
.addrsize = sizeof(sin),
.servername = "rpc.statd",
.program = &nsm_program,
.version = NSM_VERSION,
.authflavor = RPC_AUTH_NULL,
.flags = RPC_CLNT_CREATE_NOPING,
};
return rpc_create(&args);
}
static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res)
{
struct rpc_clnt *clnt;
int status;
struct nsm_args args = {
.priv = &nsm->sm_priv,
.prog = NLM_PROGRAM,
.vers = 3,
.proc = NLMPROC_NSM_NOTIFY,
.mon_name = nsm->sm_mon_name,
};
struct rpc_message msg = {
.rpc_argp = &args,
.rpc_resp = res,
};
clnt = nsm_create();
if (IS_ERR(clnt)) {
status = PTR_ERR(clnt);
dprintk("lockd: failed to create NSM upcall transport, "
"status=%d\n", status);
goto out;
}
memset(res, 0, sizeof(*res));
msg.rpc_proc = &clnt->cl_procinfo[proc];
status = rpc_call_sync(clnt, &msg, 0);
if (status < 0)
dprintk("lockd: NSM upcall RPC failed, status=%d\n",
status);
else
status = 0;
rpc_shutdown_client(clnt);
out:
return status;
}
/**
* nsm_monitor - Notify a peer in case we reboot
* @host: pointer to nlm_host of peer to notify
*
* If this peer is not already monitored, this function sends an
* upcall to the local rpc.statd to record the name/address of
* the peer to notify in case we reboot.
*
* Returns zero if the peer is monitored by the local rpc.statd;
* otherwise a negative errno value is returned.
*/
int nsm_monitor(const struct nlm_host *host)
{
struct nsm_handle *nsm = host->h_nsmhandle;
struct nsm_res res;
int status;
dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name);
if (nsm->sm_monitored)
return 0;
/*
* Choose whether to record the caller_name or IP address of
* this peer in the local rpc.statd's database.
*/
nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf;
status = nsm_mon_unmon(nsm, NSMPROC_MON, &res);
if (unlikely(res.status != 0))
status = -EIO;
if (unlikely(status < 0)) {
printk(KERN_NOTICE "lockd: cannot monitor %s\n", nsm->sm_name);
return status;
}
nsm->sm_monitored = 1;
if (unlikely(nsm_local_state != res.state)) {
nsm_local_state = res.state;
dprintk("lockd: NSM state changed to %d\n", nsm_local_state);
}
return 0;
}
/**
* nsm_unmonitor - Unregister peer notification
* @host: pointer to nlm_host of peer to stop monitoring
*
* If this peer is monitored, this function sends an upcall to
* tell the local rpc.statd not to send this peer a notification
* when we reboot.
*/
void nsm_unmonitor(const struct nlm_host *host)
{
struct nsm_handle *nsm = host->h_nsmhandle;
struct nsm_res res;
int status;
if (atomic_read(&nsm->sm_count) == 1
&& nsm->sm_monitored && !nsm->sm_sticky) {
dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name);
status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res);
if (res.status != 0)
status = -EIO;
if (status < 0)
printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",
nsm->sm_name);
else
nsm->sm_monitored = 0;
}
}
static struct nsm_handle *nsm_lookup_hostname(const char *hostname,
const size_t len)
{
struct nsm_handle *nsm;
list_for_each_entry(nsm, &nsm_handles, sm_link)
if (strlen(nsm->sm_name) == len &&
memcmp(nsm->sm_name, hostname, len) == 0)
return nsm;
return NULL;
}
static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap)
{
struct nsm_handle *nsm;
list_for_each_entry(nsm, &nsm_handles, sm_link)
if (rpc_cmp_addr(nsm_addr(nsm), sap))
return nsm;
return NULL;
}
static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv)
{
struct nsm_handle *nsm;
list_for_each_entry(nsm, &nsm_handles, sm_link)
if (memcmp(nsm->sm_priv.data, priv->data,
sizeof(priv->data)) == 0)
return nsm;
return NULL;
}
/*
* Construct a unique cookie to match this nsm_handle to this monitored
* host. It is passed to the local rpc.statd via NSMPROC_MON, and
* returned via NLMPROC_SM_NOTIFY, in the "priv" field of these
* requests.
*
* The NSM protocol requires that these cookies be unique while the
* system is running. We prefer a stronger requirement of making them
* unique across reboots. If user space bugs cause a stale cookie to
* be sent to the kernel, it could cause the wrong host to lose its
* lock state if cookies were not unique across reboots.
*
* The cookies are exposed only to local user space via loopback. They
* do not appear on the physical network. If we want greater security
* for some reason, nsm_init_private() could perform a one-way hash to
* obscure the contents of the cookie.
*/
static void nsm_init_private(struct nsm_handle *nsm)
{
u64 *p = (u64 *)&nsm->sm_priv.data;
struct timespec ts;
s64 ns;
ktime_get_ts(&ts);
ns = timespec_to_ns(&ts);
put_unaligned(ns, p);
put_unaligned((unsigned long)nsm, p + 1);
}
static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
co
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