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/*
* 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 <okir@monad.swb.de>
*/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/in.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/lockd/lockd.h>
#include <linux/lockd/sm_inter.h>
#include <linux/mutex.h>
#define NLMDBG_FACILITY NLMDBG_HOSTCACHE
#define NLM_HOST_MAX 64
#define NLM_HOST_NRHASH 32
#define NLM_ADDRHASH(addr) (ntohl(addr) & (NLM_HOST_NRHASH-1))
#define NLM_HOST_REBIND (60 * HZ)
#define NLM_HOST_EXPIRE ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ)
#define NLM_HOST_COLLECT ((nrhosts > NLM_HOST_MAX)? 120 * HZ : 60 * HZ)
static struct hlist_head nlm_hosts[NLM_HOST_NRHASH];
static unsigned long next_gc;
static int nrhosts;
static DEFINE_MUTEX(nlm_host_mutex);
static void nlm_gc_hosts(void);
static struct nsm_handle * __nsm_find(const struct sockaddr_in *,
const char *, unsigned int, int);
static struct nsm_handle * nsm_find(const struct sockaddr_in *sin,
const char *hostname,
unsigned int hostname_len);
/*
* Common host lookup routine for server & client
*/
static struct nlm_host *nlm_lookup_host(int server,
const struct sockaddr_in *sin,
int proto, u32 version,
const char *hostname,
unsigned int hostname_len,
const struct sockaddr_in *ssin)
{
struct hlist_head *chain;
struct hlist_node *pos;
struct nlm_host *host;
struct nsm_handle *nsm = NULL;
int hash;
dprintk("lockd: nlm_lookup_host("NIPQUAD_FMT"->"NIPQUAD_FMT
", p=%d, v=%u, my role=%s, name=%.*s)\n",
NIPQUAD(ssin->sin_addr.s_addr),
NIPQUAD(sin->sin_addr.s_addr), proto, version,
server? "server" : "client",
hostname_len,
hostname? hostname : "<none>");
hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
/* Lock hash table */
mutex_lock(&nlm_host_mutex);
if (time_after_eq(jiffies, next_gc))
nlm_gc_hosts();
/* We may keep several nlm_host objects for a peer, because each
* nlm_host is identified by
* (address, protocol, version, server/client)
* We could probably simplify this a little by putting all those
* different NLM rpc_clients into one single nlm_host object.
* This would allow us to have one nlm_host per address.
*/
chain = &nlm_hosts[hash];
hlist_for_each_entry(host, pos, chain, h_hash) {
if (!nlm_cmp_addr(&host->h_addr, sin))
continue;
/* See if we have an NSM handle for this client */
if (!nsm)
nsm = host->h_nsmhandle;
if (host->h_proto != proto)
continue;
if (host->h_version != version)
continue;
if (host->h_server != server)
continue;
if (!nlm_cmp_addr(&host->h_saddr, ssin))
continue;
/* Move to head of hash chain. */
hlist_del(&host->h_hash);
hlist_add_head(&host->h_hash, chain);
nlm_get_host(host);
goto out;
}
if (nsm)
atomic_inc(&nsm->sm_count);
host = NULL;
/* Sadly, the host isn't in our hash table yet. See if
* we have an NSM handle for it. If not, create one.
*/
if (!nsm && !(nsm = nsm_find(sin, hostname, hostname_len)))
goto out;
host = kzalloc(sizeof(*host), GFP_KERNEL);
if (!host) {
nsm_release(nsm);
goto out;
}
host->h_name = nsm->sm_name;
host->h_addr = *sin;
host->h_addr.sin_port = 0; /* ouch! */
host->h_saddr = *ssin;
host->h_version = version;
host->h_proto = proto;
host->h_rpcclnt = NULL;
mutex_init(&host->h_mutex);
host->h_nextrebind = jiffies + NLM_HOST_REBIND;
host->h_expires = jiffies + NLM_HOST_EXPIRE;
atomic_set(&host->h_count, 1);
init_waitqueue_head(&host->h_gracewait);
init_rwsem(&host->h_rwsem);
host->h_state = 0; /* pseudo NSM state */
host->h_nsmstate = 0; /* real NSM state */
host->h_nsmhandle = nsm;
host->h_server = server;
hlist_add_head(&host->h_hash, chain);
INIT_LIST_HEAD(&host->h_lockowners);
spin_lock_init(&host->h_lock);
INIT_LIST_HEAD(&host->h_granted);
INIT_LIST_HEAD(&host->h_reclaim);
if (++nrhosts > NLM_HOST_MAX)
next_gc = 0;
out:
mutex_unlock(&nlm_host_mutex);
return host;
}
/*
* Destroy a host
*/
static void
nlm_destroy_host(struct nlm_host *host)
{
struct rpc_clnt *clnt;
BUG_ON(!list_empty(&host->h_lockowners));
BUG_ON(atomic_read(&host->h_count));
/*
* Release NSM handle and unmonitor host.
*/
nsm_unmonitor(host);
clnt = host->h_rpcclnt;
if (clnt != NULL)
rpc_shutdown_client(clnt);
kfree(host);
}
/*
* Find an NLM server handle in the cache. If there is none, create it.
*/
struct nlm_host *nlmclnt_lookup_host(const struct sockaddr_in *sin,
int proto, u32 version,
const char *hostname,
unsigned int hostname_len)
{
struct sockaddr_in ssin = {0};
return nlm_lookup_host(0, sin, proto, version,
hostname, hostname_len, &ssin);
}
/*
* Find an NLM client handle in the cache. If there is none, create it.
*/
struct nlm_host *
nlmsvc_lookup_host(struct svc_rqst *rqstp,
const char *hostname, unsigned int hostname_len)
{
struct sockaddr_in ssin = {0};
ssin.sin_addr = rqstp->rq_daddr.addr;
return nlm_lookup_host(1, svc_addr_in(rqstp),
rqstp->rq_prot, rqstp->rq_vers,
hostname, hostname_len, &ssin);
}
/*
* 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("NIPQUAD_FMT"->"NIPQUAD_FMT")\n",
NIPQUAD(host->h_saddr.sin_addr),
NIPQUAD(host->h_addr.sin_addr));
/* 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) {
if (time_after_eq(jiffies, host->h_nextrebind)) {
rpc_force_rebind(clnt);
host->h_nextrebind = jiffies + NLM_HOST_REBIND;
dprintk("lockd: next rebind in %ld jiffies\n",
host->h_nextrebind - jiffies);
}
} else {
unsigned long increment = nlmsvc_timeout;
struct rpc_timeout timeparms = {
.to_initval = increment,
.to_increment = increment,
.to_maxval = increment * 6UL,
.to_retries = 5U,
};
struct rpc_create_args args = {
.protocol = host->h_proto,
.address = (struct sockaddr *)&host->h_addr,
.addrsize = sizeof(host->h_addr),
.saddress = (struct sockaddr *)&host->h_saddr
|