// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/lockd/host.c
*
* Management for NLM peer hosts. The nlm_host struct is shared
* between client and server implementation. The only reason to
* do so is to reduce code bloat.
*
* Copyright (C) 1996, Olaf Kirch <[email protected]>
*/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/addr.h>
#include <linux/sunrpc/svc.h>
#include <linux/lockd/lockd.h>
#include <linux/mutex.h>
#include <linux/sunrpc/svc_xprt.h>
#include <net/ipv6.h>
#include "netns.h"
#define NLMDBG_FACILITY NLMDBG_HOSTCACHE
#define NLM_HOST_NRHASH 32
#define NLM_HOST_REBIND (60 * HZ)
#define NLM_HOST_EXPIRE (300 * HZ)
#define NLM_HOST_COLLECT (120 * HZ)
static struct hlist_head nlm_server_hosts[NLM_HOST_NRHASH];
static struct hlist_head nlm_client_hosts[NLM_HOST_NRHASH];
#define for_each_host(host, chain, table) \
for ((chain) = (table); \
(chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
hlist_for_each_entry((host), (chain), h_hash)
#define for_each_host_safe(host, next, chain, table) \
for ((chain) = (table); \
(chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
hlist_for_each_entry_safe((host), (next), \
(chain), h_hash)
static unsigned long nrhosts;
static DEFINE_MUTEX(nlm_host_mutex);
static void nlm_gc_hosts(struct net *net);
struct nlm_lookup_host_info {
const int server; /* search for server|client */
const struct sockaddr *sap; /* address to search for */
const size_t salen; /* it's length */
const unsigned short protocol; /* transport to search for*/
const u32 version; /* NLM version to search for */
const char *hostname; /* remote's hostname */
const size_t hostname_len; /* it's length */
const int noresvport; /* use non-priv port */
struct net *net; /* network namespace to bind */
const struct cred *cred;
};
/*
* Hash function must work well on big- and little-endian platforms
*/
static unsigned int __nlm_hash32(const __be32 n)
{
unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
return hash ^ (hash >> 8);
}
static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
{
const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
return __nlm_hash32(sin->sin_addr.s_addr);
}
static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
{
const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
const struct in6_addr addr = sin6->sin6_addr;
return __nlm_hash32(addr.s6_addr32[0]) ^
__nlm_hash32(addr.s6_addr32[1]) ^
__nlm_hash32(addr.s6_addr32[2]) ^
__nlm_hash32(addr.s6_addr32[3]);
}
static unsigned int nlm_hash_address(const struct sockaddr *sap)
{
unsigned int hash;
switch (sap->sa_family) {
case AF_INET:
hash = __nlm_hash_addr4(sap);
break;
case AF_INET6:
hash = __nlm_hash_addr6(sap);
break;
default:
hash = 0;
}
return hash & (NLM_HOST_NRHASH - 1);
}
/*
* Allocate and initialize an nlm_host. Common to both client and server.
*/
static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni,
struct nsm_handle *nsm)
{
struct nlm_host *host = NULL;
unsigned long now = jiffies;
if (nsm != NULL)
refcount_inc(&nsm->sm_count);
else {
nsm = nsm_get_handle(ni->net, ni->sap, ni->salen,
ni->hostname, ni->hostname_len);
if (unlikely(nsm == NULL)) {
dprintk("lockd: %s failed; no nsm handle\n",
__func__);
goto out;
}
}
host = kmalloc(sizeof(*host), GFP_KERNEL);
if (unlikely(host == NULL)) {
dprintk("lockd: %s failed; no memory\n", __func__);
nsm_release(nsm);
goto out;
}
memcpy(nlm_addr(host), ni->sap, ni->salen);
host->h_addrlen = ni->salen;
rpc_set_port(nlm_addr(host), 0);
host->h_srcaddrlen = 0;
host->h_rpcclnt = NULL;
host->h_name = nsm->sm_name;
host->h_version = ni->version;
host->h_proto = ni->protocol;
host->h_reclaiming = 0;
host->h_server = ni->server;
host->h_noresvport = ni->noresvport;
host->h_inuse = 0;
init_waitqueue_head(&host->h_gracewait);
init_rwsem(&host->h_rwsem);
host->h_state = 0;
host->h_nsmstate = 0;
host->h_pidcount = 0;
refcount_set(&host->h_count, 1);
mutex_init(&host->h_mutex);
host->h_nextrebind = now + NLM_HOST_REBIND;
host->h_expires = now + NLM_HOST_EXPIRE;
INIT_LIST_HEAD(&host->h_lockowners);
spin_lock_init(&host->h_lock);
INIT_LIST_HEAD(&host->h_granted);
INIT_LIST_HEAD(&host->h_reclaim);
host->h_nsmhandle = nsm;
host->h_addrbuf = nsm->sm_addrbuf;
host->net = ni->net;
host->h_cred = get_cred(ni->cred);
strscpy(host->nodename, utsname()->nodename, sizeof(host->nodename));
out:
return host;
}
/*
* Destroy an nlm_host and free associated resources
*
* Caller must hold nlm_host_mutex.
*/
static void nlm_destroy_host_locked(struct nlm_host *host)
{
struct rpc_clnt *clnt;
struct lockd_net *ln = net_generic(host->net, lockd_net_id);
dprintk("lockd: destroy host %s\n", host->h_name);
hlist_del_init(&host->h_hash);
nsm_unmonitor(host);
nsm_release(host->h_nsmhandle);
clnt = host->h_rpcclnt;
if (clnt != NULL)
rpc_shutdown_client(clnt);
put_cred(host->h_cred);
kfree(host);
ln->nrhosts--;
nrhosts--;
}
/**
* nlmclnt_lookup_host - Find an NLM host handle matching a remote server
* @sap: network address of server
* @salen: length of server address
* @protocol: transport protocol to use
* @version: NLM protocol version
* @hostname: '\0'-terminated hostname of server
* @noresvport: 1 if non-privileged port should be used
* @net: pointer to net namespace
* @cred: pointer to cred
*
* Returns an nlm_host structure that matches the passed-in
* [server address, transport protocol, NLM version, server hostname].
* If one doesn't already exist in the host cache, a new handle is
* created and returned.
*/
struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
const size_t salen,
const unsigned short protocol,
const u32 version,
const char *hostname,
int noresvport,
struct net *net,
const struct cred *cred)
{
struct nlm_lookup_host_info ni = {
.server = 0,
.sap = sap,
.salen = salen,
.protocol = protocol,
.version = version,
.hostname = hostname,
.hostname_len = strlen(hostname),
.noresvport = noresvport,
.net = net,
.cred = cred,
};
struct hlist_head *chain;
struct nlm_host *host;
struct nsm_handle *nsm = NULL;
struct lockd_net *ln = net_generic(net, lockd_net_id);
dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
(hostname ? hostname : "<none>"), version,
(protocol == IPPROTO_UDP ? "udp" : "tcp"));
mutex_lock(&nlm_host_mutex);
chain = &nlm_client_hosts[nlm_hash_address(sap)];
hlist_for_each_entry(host, chain, h_hash) {
if (host->net != net)
continue;
if (!rpc_cmp_addr(nlm_addr(host), sap))
continue;
/* Same address. Share an NSM handle if we already have one */
if (nsm == NULL)
nsm = host->h_nsmhandle;
if (host->h_proto != protocol)
continue;
if (host->h_version != version)
continue;
nlm_get_host(host);
dprintk("lockd: %s found host %s (%s)\n", __func__,
host->h_name, host->h_addrbuf);
goto out;
}
host = nlm_alloc_host(&ni, nsm);
if (unlikely(host == NULL))
goto out;
hlist_add_head(&host->h_hash, chain);
ln->nrhosts++;
nrhosts++;
dprintk("lockd: %s created host %s (%s)\n", __func__,
host->h_name, host->h_addrbuf);
out:
mutex_unlock(&nlm_host_mutex);
return host;
}
/**
* nlmclnt_release_host - release client nlm_host
* @host: nlm_host to release
*
*/
void nlmclnt_release_host(struct nlm_host *host)
{
if (host == NULL)
return;
dprintk("lockd: release client host %s\n", host->h_name);
WARN_ON_ONCE(host->h_server);
if (refcount_dec_and_mutex_lock(&host->h_count, &nlm_host_mutex)) {
WARN_ON_ONCE(!list_empty(&host->h_lockowners));
WARN_ON_ONCE(!list_empty(&host->h_granted));
WARN_ON_ONCE(!list_empty(&host->h_reclaim));
nlm_destroy_host_locked(host);
mutex_unlock(&nlm_host_mutex);
}
}
/**
* nlmsvc_lookup_host - Find an NLM host handle matching a remote client
* @rqstp: incoming NLM request
* @hostname: name of client host
* @hostname_len: length of client hostname
*
* Returns an nlm_host structure that matches the [client address,
* transport protocol, NLM version, client hostname] of the passed-in
* NLM request. If one doesn't already exist in the host cache, a
* new handle is created and returned.
*
* Before possibly creating a new nlm_host, construct a sockaddr
* for a specific source address in case the local system has
* multiple network addresses. The family of the address in
* rq_daddr is guaranteed to be the same as the family of the
* address in rq_addr, so it's safe to use the same family for
* the source address.
*/
struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
const char *hostname,
const size_t hostname_len)
{
struct hlist_head *chain;
struct nlm_host *host = NULL;
struct nsm_handle *nsm = NULL;
struct sockaddr *src_sap = svc_daddr(rqstp);
size_t src_len = rqstp->rq_daddrlen;
struct net *net = SVC_NET(rqstp);
struct nlm_lookup_host_info ni = {
.server = 1,
.sap = svc_addr(rqstp),
.salen = rqstp->rq_addrlen,
.protocol = rqstp->rq_prot,
.version = rqstp->rq_vers,
.hostname = hostname,
.hostname_len = hostname_len,
.net = net,
};
struct lockd_net *ln = net_generic(net, lockd_net_id);
dprintk("lockd: %s(host='%.*s', vers=%u, proto=%s)\n", __func__,
(int)hostname_len, hostname, rqstp->rq_vers,
(rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
mutex_lock(&nlm_host_mutex);
if (time_after_eq(jiffies, ln->next_gc))
nlm_gc_hosts(net);
chain = &nlm_server_hosts[nlm_hash_address(ni.sap)];
hlist_for_each_entry(host, chain, h_hash) {
if (host->net != net)
continue;
if (!rpc_cmp_addr(nlm_addr(host), ni.sap))
continue;
/* Same address. Share an NSM handle if we already have one */
if (nsm == NULL)
nsm = host->h_nsmhandle;
if (host->h_proto != ni.protocol)
continue;
if (host->h_version != ni.version)
continue;
if (!rpc_cmp_addr(nlm_srcaddr(host), src_sap))
continue;
/* Move to head of hash chain. */
hlist_del(&host->h_hash);
hlist_add_head(&host->h_hash, chain);
nlm_get_host(host);
dprintk("lockd: %s found host %s (%s)\n",
__func__, host->h_name, host->h_addrbuf);
goto out;
}
host = nlm_alloc_host(&ni, nsm);
if (unlikely(host == NULL))
goto out;
memcpy(nlm_srcaddr(host), src_sap, src_len);
host->h_srcaddrlen = src_len;
hlist_add_head(&host->h_hash, chain);
ln->nrhosts++;
nrhosts++;
refcount_inc(&host->h_count);
dprintk("lockd: %s created host %s (%s)\n",
__func__, host->h_name, host->h_addrbuf);
out:
mutex_unlock(&nlm_host_mutex);
return host;
}
/**
* nlmsvc_release_host - release server nlm_host
* @host: nlm_host to release
*
* Host is destroyed later in nlm_gc_host().
*/
void nlmsvc_release_host(struct nlm_host *host)
{
if (host == NULL)
return;
dprintk("lockd: release server host %s\n", host->h_name);
WARN_ON_ONCE(!host->h_server);
refcount_dec(&host->h_count);
}
/*
* Create the NLM RPC client for an NLM peer
*/
struct rpc_clnt *
nlm_bind_host(struct nlm_host *host)
{
struct rpc_clnt *clnt;
dprintk("lockd: nlm_bind_host %s (%s)\n",
host->h_name, host->h_addrbuf);
/* Lock host handle */
mutex_lock(&host->h_mutex);
/* If we've already created an RPC client, check whether
* RPC rebind is required
*/
if ((clnt = host->h_rpcclnt) != NULL) {
nlm_rebind_host(host);
} else {
unsigned long increment = nlm_timeout * HZ;
struct rpc_timeout timeparms = {
.to_initval = increment,
.to_increment = increment,
.to_maxval = increment * 6UL,
.to_retries = 5U,
};
struct rpc_create_args args = {
.net = host->net,
.protocol = host->h_proto,
.address = nlm_addr(host),
.addrsize = host->h_addrlen,
.timeout = &timeparms,
.servername = host->h_name,
.program = &nlm_program,
.version = host->h_version,
.authflavor = RPC_AUTH_UNIX,
.flags = (RPC_CLNT_CREATE_NOPING |
RPC_CLNT_CREATE_AUTOBIND |
RPC_CLNT_CREATE_REUSEPORT),
.cred = host->h_cred,
};
/*
* lockd retries server side blocks automatically so we want
* those to be soft RPC calls. Client side calls need to be
* hard RPC tasks.
*/
if (!host->h_server)
args.flags |= RPC_CLNT_CREATE_HARDRTRY;
if (host->h_noresvport)
args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
if (host->h_srcaddrlen)
args.saddress = nlm_srcaddr(host);
clnt = rpc_create(&args);
if (!IS_ERR(clnt))
host->h_rpcclnt = clnt;
else {
printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
clnt = NULL;
}
}
mutex_unlock(&host->h_mutex);
return clnt;
}
/**
* nlm_rebind_host - If needed, force a portmap lookup of the peer's lockd port
* @host: NLM host handle for peer
*
* This is not needed when using a connection-oriented protocol, such as TCP.
* The existing autobind mechanism is sufficient to force a rebind when
* required, e.g. on connection state transitions.
*/
void
nlm_rebind_host(struct nlm_host *host)
{
if (host->h_proto != IPPROTO_UDP)
return;
if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
rpc_force_rebind(host->h_rpcclnt);
host->h_nextrebind = jiffies + NLM_HOST_REBIND;
}
}
/*
* Increment NLM host count
*/
struct nlm_host * nlm_get_host(struct nlm_host *host)
{
if (host) {
dprintk("lockd: get host %s\n", host->h_name);
refcount_inc(&host->h_count);
host->h_expires = jiffies + NLM_HOST_EXPIRE;
}
return host;
}
static struct nlm_host *next_host_state(struct hlist_head *cache,
struct nsm_handle *nsm,
const struct nlm_reboot *info)
{
struct nlm_host *host;
struct hlist_head *chain;
mutex_lock(&nlm_host_mutex);
for_each_host(host, chain, cache) {
if (host->h_nsmhandle == nsm
&& host->h_nsmstate != info->state) {
host->h_nsmstate = info->state;
host->h_state++;
nlm_get_host(host);
mutex_unlock(&nlm_host_mutex);
return host;
}
}
mutex_unlock(&nlm_host_mutex);
return NULL;
}
/**
* nlm_host_rebooted - Release all resources held by rebooted host
* @net: network namespace
* @info: pointer to decoded results of NLM_SM_NOTIFY call
*
* We were notified that the specified host has rebooted. Release
* all resources held by that peer.
*/
void nlm_host_rebooted(const struct net *net, const struct nlm_reboot *info)
{
struct nsm_handle *nsm;
struct nlm_host *host;
nsm = nsm_reboot_lookup(net, info);
if (unlikely(nsm == NULL))
return;
/* Mark all hosts tied to this NSM state as having rebooted.
* We run the loop repeatedly, because we drop the host table
* lock for this.
* To avoid processing a host several times, we match the nsmstate.
*/
while ((host = next_host_state(nlm_server_hosts, nsm, info)) != NULL) {
nlmsvc_free_host_resources(host);
nlmsvc_release_host(host);
}
while ((host = next_host_state(nlm_client_hosts, nsm, info)) != NULL) {
nlmclnt_recovery(host);
nlmclnt_release_host(host);
}
nsm_release(nsm);
}
static void nlm_complain_hosts(struct net *net)
{
struct hlist_head *chain;
struct nlm_host *host;
if (net) {
struct lockd_net *ln = net_generic(net, lockd_net_id);
if (ln->nrhosts == 0)
return;
pr_warn("lockd: couldn't shutdown host module for net %x!\n",
net->ns.inum);
dprintk("lockd: %lu hosts left in net %x:\n", ln->nrhosts,
net->ns.inum);
} else {
if (nrhosts == 0)
return;
printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
dprintk("lockd: %lu hosts left:\n", nrhosts);
}
for_each_host(host, chain, nlm_server_hosts) {
if (net && host->net != net)
continue;
dprintk(" %s (cnt %d use %d exp %ld net %x)\n",
host->h_name, refcount_read(&host->h_count),
host->h_inuse, host->h_expires, host->net->ns.inum);
}
}
void
nlm_shutdown_hosts_net(struct net *net)
{
struct hlist_head *chain;
struct nlm_host *host;
mutex_lock(&nlm_host_mutex);
/* First, make all hosts eligible for gc */
dprintk("lockd: nuking all hosts in net %x...\n",
net ? net->ns.inum : 0);
for_each_host(host, chain, nlm_server_hosts) {
if (net && host->net != net)
continue;
host->h_expires = jiffies - 1;
if (host->h_rpcclnt) {
rpc_shutdown_client(host->h_rpcclnt);
host->h_rpcclnt = NULL;
}
nlmsvc_free_host_resources(host);
}
/* Then, perform a garbage collection pass */
nlm_gc_hosts(net);
nlm_complain_hosts(net);
mutex_unlock(&nlm_host_mutex);
}
/*
* Shut down the hosts module.
* Note that this routine is called only at server shutdown time.
*/
void
nlm_shutdown_hosts(void)
{
dprintk("lockd: shutting down host module\n");
nlm_shutdown_hosts_net(NULL);
}
/*
* Garbage collect any unused NLM hosts.
* This GC combines reference counting for async operations with
* mark & sweep for resources held by remote clients.
*/
static void
nlm_gc_hosts(struct net *net)
{
struct hlist_head *chain;
struct hlist_node *next;
struct nlm_host *host;
dprintk("lockd: host garbage collection for net %x\n",
net ? net->ns.inum : 0);
for_each_host(host, chain, nlm_server_hosts) {
if (net && host->net != net)
continue;
host->h_inuse = 0;
}
/* Mark all hosts that hold locks, blocks or shares */
nlmsvc_mark_resources(net);
for_each_host_safe(host, next, chain, nlm_server_hosts) {
if (net && host->net != net)
continue;
if (host->h_inuse || time_before(jiffies, host->h_expires)) {
dprintk("nlm_gc_hosts skipping %s "
"(cnt %d use %d exp %ld net %x)\n",
host->h_name, refcount_read(&host->h_count),
host->h_inuse, host->h_expires,
host->net->ns.inum);
continue;
}
if (refcount_dec_if_one(&host->h_count))
nlm_destroy_host_locked(host);
}
if (net) {
struct lockd_net *ln = net_generic(net, lockd_net_id);
ln->next_gc = jiffies + NLM_HOST_COLLECT;
}
}
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