/*
* 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/sunrpc/clnt.h>
#include <linux/sunrpc/xprtsock.h>
#include <linux/sunrpc/svc.h>
#include <linux/lockd/lockd.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_clnt * nsm_create(void);
static struct rpc_program nsm_program;
static LIST_HEAD(nsm_handles);
static DEFINE_SPINLOCK(nsm_lock);
/*
* Local NSM state
*/
int __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 void nsm_display_ipv4_address(const struct sockaddr *sap, char *buf,
const size_t len)
{
const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
snprintf(buf, len, "%pI4", &sin->sin_addr.s_addr);
}
static void nsm_display_ipv6_address(const struct sockaddr *sap, char *buf,
const size_t len)
{
const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
if (ipv6_addr_v4mapped(&sin6->sin6_addr))
snprintf(buf, len, "%pI4", &sin6->sin6_addr.s6_addr32[3]);
else if (sin6->sin6_scope_id != 0)
snprintf(buf, len, "%pI6%%%u", &sin6->sin6_addr,
sin6->sin6_scope_id);
else
snprintf(buf, len, "%pI6", &sin6->sin6_addr);
}
static void nsm_display_address(const struct sockaddr *sap,
char *buf, const size_t len)
{
switch (sap->sa_family) {
case AF_INET:
nsm_display_ipv4_address(sap, buf, len);
break;
case AF_INET6:
nsm_display_ipv6_address(sap, buf, len);
break;
default:
snprintf(buf, len, "unsupported address family");
break;
}
}
/*
* Common procedure for NSMPROC_MON/NSMPROC_UNMON calls
*/
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 (res.status != 0)
status = -EIO;
if (status < 0)
printk(KERN_NOTICE "lockd: cannot monitor %s\n", nsm->sm_name);
else
nsm->sm_monitored = 1;
return status;
}
/**
* 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 (nlm_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;
ktime_get_ts(&ts);
*p++ = timespec_to_ns(&ts);
*p = (unsigned long)nsm;
}
static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
const size_t salen,
const char *hostname,
const size_t hostname_len)
{
struct nsm_handle *new;
new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL);
if (unlikely(new == NULL))
return NULL;
atomic_set(&new->sm_count, 1);
new->sm_name = (char *)(new + 1);
memcpy(nsm_addr(new), sap, salen);
new->sm_addrlen = salen;
nsm_init_private(new);
nsm_display_address((const struct sockaddr *)&new->sm_addr,
new->sm_addrbuf, sizeof(new->sm_addrbuf));
memcpy(new->sm_name, hostname, hostname_len);
new->sm_name[hostname_len] = '\0';
return new;
}
/**
* nsm_get_handle - Find or create a cached nsm_handle
* @sap: pointer to socket address of handle to find
* @salen: length of socket address
* @hostname: pointer to C string containing hostname to find
* @hostname_len: length of C string
*
* Behavior is modulated by the global nsm_use_hostnames variable.
*
* Returns a cached nsm_handle after bumping its ref count, or
* returns a fresh nsm_handle if a handle that matches @sap and/or
* @hostname cannot be found in the handle cache. Returns NULL if
* an error occurs.
*/
struct nsm_handle *nsm_get_handle(const struct sockaddr *sap,
const size_t salen, const char *hostname,
const size_t hostname_len)
{
struct nsm_handle *cached, *new = NULL;
if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
if (printk_ratelimit()) {
printk(KERN_WARNING "Invalid hostname \"%.*s\" "
"in NFS lock request\n",
(int)hostname_len, hostname);
}
return NULL;
}
retry:
spin_lock(&nsm_lock);
if (nsm_use_hostnames && hostname != NULL)
cached = nsm_lookup_hostname(hostname, hostname_len);
else
cached = nsm_lookup_addr(sap);
if (cached != NULL) {
atomic_inc(&cached->sm_count);
spin_unlock(&nsm_lock);
kfree(new);
dprintk("lockd: found nsm_handle for %s (%s), "
"cnt %d\n", cached->sm_name,
cached->sm_addrbuf,
atomic_read(&cached->sm_count));
return cached;
}
if (new != NULL) {
list_add(&new->sm_link, &nsm_handles);
spin_unlock(&nsm_lock);
dprintk("lockd: created nsm_handle for %s (%s)\n",
new->sm_name, new->sm_addrbuf);
return new;
}
spin_unlock(&nsm_lock);
new = nsm_create_handle(sap, salen, hostname, hostname_len);
if (unlikely(new == NULL))
return NULL;
goto retry;
}
/**
* nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle
* @info: pointer to NLMPROC_SM_NOTIFY arguments
*
* Returns a matching nsm_handle if found in the nsm cache; the returned
* nsm_handle's reference count is bumped and sm_monitored is cleared.
* Otherwise returns NULL if some error occurred.
*/
struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info)
{
struct nsm_handle *cached;
spin_lock(&nsm_lock);
cached = nsm_lookup_priv(&info->priv);
if (unlikely(cached == NULL)) {
spin_unlock(&nsm_lock);
dprintk("lockd: never saw rebooted peer '%.*s' before\n",
info->len, info->mon);
return cached;
}
atomic_inc(&cached->sm_count);
spin_unlock(&nsm_lock);
/*
* During subsequent lock activity, force a fresh
* notification to be set up for this host.
*/
cached->sm_monitored = 0;
dprintk("lockd: host %s (%s) rebooted, cnt %d\n",
cached->sm_name, cached->sm_addrbuf,
atomic_read(&cached->sm_count));
return cached;
}
/**
* nsm_release - Release an NSM handle
* @nsm: pointer to handle to be released
*
*/
void nsm_release(struct nsm_handle *nsm)
{
if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
list_del(&nsm->sm_link);
spin_unlock(&nsm_lock);
dprintk("lockd: destroyed nsm_handle for %s (%s)\n",
nsm->sm_name, nsm->sm_addrbuf);
kfree(nsm);
}
}
/*
* Create NSM client for the local host
*/
static struct rpc_clnt *
nsm_create(void)
{
struct sockaddr_in sin = {
.sin_family = AF_INET,
.sin_addr.s_addr = htonl(INADDR_LOOPBACK),
.sin_port = 0,
};
struct rpc_create_args args = {
.protocol = XPRT_TRANSPORT_UDP,
.address = (struct sockaddr *)&sin,
.addrsize = sizeof(sin),
.servername = "localhost",
.program = &nsm_program,
.version = NSM_VERSION,
.authflavor = RPC_AUTH_NULL,
};
return rpc_create(&args);
}
/*
* XDR functions for NSM.
*
* See http://www.opengroup.org/ for details on the Network
* Status Monitor wire protocol.
*/
static int encode_nsm_string(struct xdr_stream *xdr, const char *string)
{
const u32 len = strlen(string);
__be32 *p;
if (unlikely(len > SM_MAXSTRLEN))
return -EIO;
p = xdr_reserve_space(xdr, sizeof(u32) + len);
if (unlikely(p == NULL))
return -EIO;
xdr_encode_opaque(p, string, len);
return 0;
}
/*
* "mon_name" specifies the host to be monitored.
*/
static int encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp)
{
return encode_nsm_string(xdr, argp->mon_name);
}
/*
* The "my_id" argument specifies the hostname and RPC procedure
* to be called when the status manager receives notification
* (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name"
* has changed.
*/
static int encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
{
int status;
__be32 *p;
status = encode_nsm_string(xdr, utsname()->nodename);
if (unlikely(status != 0))
return status;
p = xdr_reserve_space(xdr, 3 * sizeof(u32));
if (unlikely(p == NULL))
return -EIO;
*p++ = htonl(argp->prog);
*p++ = htonl(argp->vers);
*p++ = htonl(argp->proc);
return 0;
}
/*
* The "mon_id" argument specifies the non-private arguments
* of an NSMPROC_MON or NSMPROC_UNMON call.
*/
static int encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp)
{
int status;
status = encode_mon_name(xdr, argp);
if (unlikely(status != 0))
return status;
return encode_my_id(xdr, argp);
}
/*
* The "priv" argument may contain private information required
* by the NSMPROC_MON call. This information will be supplied in the
* NLMPROC_SM_NOTIFY call.
*/
static int encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp)
{
__be32 *p;
p = xdr_reserve_space(xdr, SM_PRIV_SIZE);
if (unlikely(p == NULL))
return -EIO;
xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE);
return 0;
}
static int xdr_enc_mon(struct rpc_rqst *req, __be32 *p,
const struct nsm_args *argp)
{
struct xdr_stream xdr;
int status;
xdr_init_encode(&xdr, &req->rq_snd_buf, p);
status = encode_mon_id(&xdr, argp);
if (unlikely(status))
return status;
return encode_priv(&xdr, argp);
}
static int xdr_enc_unmon(struct rpc_rqst *req, __be32 *p,
const struct nsm_args *argp)
{
struct xdr_stream xdr;
xdr_init_encode(&xdr, &req->rq_snd_buf, p);
return encode_mon_id(&xdr, argp);
}
static int xdr_dec_stat_res(struct rpc_rqst *rqstp, __be32 *p,
struct nsm_res *resp)
{
struct xdr_stream xdr;
xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
p = xdr_inline_decode(&xdr, 2 * sizeof(u32));
if (unlikely(p == NULL))
return -EIO;
resp->status = ntohl(*p++);
resp->state = ntohl(*p);
dprintk("lockd: xdr_dec_stat_res status %d state %d\n",
resp->status, resp->state);
return 0;
}
static int xdr_dec_stat(struct rpc_rqst *rqstp, __be32 *p,
struct nsm_res *resp)
{
struct xdr_stream xdr;
xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
p = xdr_inline_decode(&xdr, sizeof(u32));
if (unlikely(p == NULL))
return -EIO;
resp->state = ntohl(*p);
dprintk("lockd: xdr_dec_stat state %d\n", resp->state);
return 0;
}
#define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN))
#define SM_my_id_sz (SM_my_name_sz+3)
#define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN))
#define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz)
#define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE))
#define SM_mon_sz (SM_mon_id_sz+SM_priv_sz)
#define SM_monres_sz 2
#define SM_unmonres_sz 1
static struct rpc_procinfo nsm_procedures[] = {
[NSMPROC_MON] = {
.p_proc = NSMPROC_MON,
.p_encode = (kxdrproc_t)xdr_enc_mon,
.p_decode = (kxdrproc_t)xdr_dec_stat_res,
.p_arglen = SM_mon_sz,
.p_replen = SM_monres_sz,
.p_statidx = NSMPROC_MON,
.p_name = "MONITOR",
},
[NSMPROC_UNMON] = {
.p_proc = NSMPROC_UNMON,
.p_encode = (kxdrproc_t)xdr_enc_unmon,
.p_decode = (kxdrproc_t)xdr_dec_stat,
.p_arglen = SM_mon_id_sz,
.p_replen = SM_unmonres_sz,
.p_statidx = NSMPROC_UNMON,
.p_name = "UNMONITOR",
},
};
static struct rpc_version nsm_version1 = {
.number = 1,
.nrprocs = ARRAY_SIZE(nsm_procedures),
.procs = nsm_procedures
};
static struct rpc_version * nsm_version[] = {
[1] = &nsm_version1,
};
static struct rpc_stat nsm_stats;
static struct rpc_program nsm_program = {
.name = "statd",
.number = NSM_PROGRAM,
.nrvers = ARRAY_SIZE(nsm_version),
.version = nsm_version,
.stats = &nsm_stats
};
