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DEFINITIONS
This source file includes following definitions.
- __nlm_hash32
- __nlm_hash_addr4
- __nlm_hash_addr6
- nlm_hash_address
- nlm_clear_port
- nlm_display_address
- nlm_lookup_host
- nlm_destroy_host
- nlmclnt_lookup_host
- nlmsvc_lookup_host
- nlm_bind_host
- nlm_rebind_host
- nlm_get_host
- nlm_release_host
- nlm_host_rebooted
- nlm_shutdown_hosts
- nlm_gc_hosts
- nsm_find
- nsm_release
/*
* 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/in6.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>
#include <net/ipv6.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_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 *sap,
const size_t salen,
const char *hostname,
const size_t hostname_len,
const int create);
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 struct sockaddr *src_sap; /* our address (optional) */
const size_t src_len; /* it's length */
};
/*
* 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);
}
static void nlm_clear_port(struct sockaddr *sap)
{
switch (sap->sa_family) {
case AF_INET:
((struct sockaddr_in *)sap)->sin_port = 0;
break;
case AF_INET6:
((struct sockaddr_in6 *)sap)->sin6_port = 0;
break;
}
}
static void nlm_display_address(const struct sockaddr *sap,
char *buf, const size_t len)
{
const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
switch (sap->sa_family) {
case AF_UNSPEC:
snprintf(buf, len, "unspecified");
break;
case AF_INET:
snprintf(buf, len, NIPQUAD_FMT, NIPQUAD(sin->sin_addr.s_addr));
break;
case AF_INET6:
if (ipv6_addr_v4mapped(&sin6->sin6_addr))
snprintf(buf, len, NIPQUAD_FMT,
NIPQUAD(sin6->sin6_addr.s6_addr32[3]));
else
snprintf(buf, len, NIP6_FMT, NIP6(sin6->sin6_addr));
break;
default:
snprintf(buf, len, "unsupported address family");
break;
}
}
/*
* Common host lookup routine for server & client
*/
static struct nlm_host *nlm_lookup_host(struct nlm_lookup_host_info *ni)
{
struct hlist_head *chain;
struct hlist_node *pos;
struct nlm_host *host;
struct nsm_handle *nsm = NULL;
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[nlm_hash_address(ni->sap)];
hlist_for_each_entry(host, pos, chain, h_hash) {
if (!nlm_cmp_addr(nlm_addr(host), ni->sap))
continue;
/* See if we have an NSM handle for this client */
if (!nsm)
nsm = host->h_nsmhandle;
if (host->h_proto != ni->protocol)
continue;
if (host->h_version != ni->version)
continue;
if (host->h_server != ni->server)
continue;
if (!nlm_cmp_addr(nlm_srcaddr(host), ni->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: nlm_lookup_host found host %s (%s)\n",
host->h_name, host->h_addrbuf);
goto out;
}
/*
* The host wasn't in our hash table. If we don't
* have an NSM handle for it yet, create one.
*/
if (nsm)
atomic_inc(&nsm->sm_count);
else {
host = NULL;
nsm = nsm_find(ni->sap, ni->salen,
ni->hostname, ni->hostname_len, 1);
if (!nsm) {
dprintk("lockd: nlm_lookup_host failed; "
"no nsm handle\n");
goto out;
}
}
host = kzalloc(sizeof(*host), GFP_KERNEL);
if (!host) {
nsm_release(nsm);
dprintk("lockd: nlm_lookup_host failed; no memory\n");
goto out;
}
host->h_name = nsm->sm_name;
memcpy(nlm_addr(host), ni->sap, ni->salen);
host->h_addrlen = ni->salen;
nlm_clear_port(nlm_addr(host));
memcpy(nlm_srcaddr(host), ni->src_sap, ni->src_len);
host->h_version = ni->version;
host->h_proto = ni->protocol;
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 = ni->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);
nrhosts++;
nlm_display_address((struct sockaddr *)&host->h_addr,
host->h_addrbuf, sizeof(host->h_addrbuf));
nlm_display_address((struct sockaddr *)&host->h_srcaddr,
host->h_srcaddrbuf, sizeof(host->h_srcaddrbuf));
dprintk("lockd: nlm_lookup_host created host %s\n",
host->h_name);
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);
}
/**
* 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
*
* 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)
{
const struct sockaddr source = {
.sa_family = AF_UNSPEC,
};
struct nlm_lookup_host_info ni = {
.server = 0,
.sap = sap,
.salen = salen,
.protocol = protocol,
.version = version,
.hostname = hostname,
.hostname_len = strlen(hostname),
.src_sap = &source,
.src_len = sizeof(source),
};
dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
(hostname ? hostname : "<none>"), version,
(protocol == IPPROTO_UDP ? "udp" : "tcp"));
return nlm_lookup_host(&ni);
}
/**
* 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 sockaddr_in sin = {
.sin_family = AF_INET,
};
struct sockaddr_in6 sin6 = {
.sin6_family = AF_INET6,
};
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,
.src_len = rqstp->rq_addrlen,
};
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"));
switch (ni.sap->sa_family) {
case AF_INET:
sin.sin_addr.s_addr = rqstp->rq_daddr.addr.s_addr;
ni.src_sap = (struct sockaddr *)&sin;
break;
case AF_INET6:
ipv6_addr_copy(&sin6.sin6_addr, &rqstp->rq_daddr.addr6);
ni.src_sap = (struct sockaddr *)&sin6;
break;
default:
return NULL;
}
return nlm_lookup_host(&ni);
}
/*
* 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), my addr=%s\n",
host->h_name, host->h_addrbuf, host->h_srcaddrbuf);
/* 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 %lu 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 = nlm_addr(host),
.addrsize = host->h_addrlen,
.saddress = nlm_srcaddr(host),
.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),
};
/*
* 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;
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;
}
/*
* Force a portmap lookup of the remote lockd port
*/
void
nlm_rebind_host(struct nlm_host *host)
{
dprintk("lockd: rebind host %s\n", host->h_name);
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);
atomic_inc(&host->h_count);
host->h_expires = jiffies + NLM_HOST_EXPIRE;
}
return host;
}
/*
* Release NLM host after use
*/
void nlm_release_host(struct nlm_host *host)
{
if (host != NULL) {
dprintk("lockd: release host %s\n", host->h_name);
BUG_ON(atomic_read(&host->h_count) < 0);
if (atomic_dec_and_test(&host->h_count)) {
BUG_ON(!list_empty(&host->h_lockowners));
BUG_ON(!list_empty(&host->h_granted));
BUG_ON(!list_empty(&host->h_reclaim));
}
}
}
/*
* We were notified that the host indicated by address &sin
* has rebooted.
* Release all resources held by that peer.
*/
void nlm_host_rebooted(const struct sockaddr_in *sin,
const char *hostname,
unsigned int hostname_len,
u32 new_state)
{
struct hlist_head *chain;
struct hlist_node *pos;
struct nsm_handle *nsm;
struct nlm_host *host;
nsm = nsm_find((struct sockaddr *)sin, sizeof(*sin),
hostname, hostname_len, 0);
if (nsm == NULL) {
dprintk("lockd: never saw rebooted peer '%.*s' before\n",
hostname_len, hostname);
return;
}
dprintk("lockd: nlm_host_rebooted(%.*s, %s)\n",
hostname_len, hostname, nsm->sm_addrbuf);
/* When reclaiming locks on this peer, make sure that
* we set up a new notification */
nsm->sm_monitored = 0;
/* 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.
*/
again: mutex_lock(&nlm_host_mutex);
for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
hlist_for_each_entry(host, pos, chain, h_hash) {
if (host->h_nsmhandle == nsm
&& host->h_nsmstate != new_state) {
host->h_nsmstate = new_state;
host->h_state++;
nlm_get_host(host);
mutex_unlock(&nlm_host_mutex);
if (host->h_server) {
/* We're server for this guy, just ditch
* all the locks he held. */
nlmsvc_free_host_resources(host);
} else {
/* He's the server, initiate lock recovery. */
nlmclnt_recovery(host);
}
nlm_release_host(host);
goto again;
}
}
}
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)
{
struct hlist_head *chain;
struct hlist_node *pos;
struct nlm_host *host;
dprintk("lockd: shutting down host module\n");
mutex_lock(&nlm_host_mutex);
/* First, make all hosts eligible for gc */
dprintk("lockd: nuking all hosts...\n");
for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
hlist_for_each_entry(host, pos, chain, h_hash) {
host->h_expires = jiffies - 1;
if (host->h_rpcclnt) {
rpc_shutdown_client(host->h_rpcclnt);
host->h_rpcclnt = NULL;
}
}
}
/* Then, perform a garbage collection pass */
nlm_gc_hosts();
mutex_unlock(&nlm_host_mutex);
/* complain if any hosts are left */
if (nrhosts) {
printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
dprintk("lockd: %d hosts left:\n", nrhosts);
for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
hlist_for_each_entry(host, pos, chain, h_hash) {
dprintk(" %s (cnt %d use %d exp %ld)\n",
host->h_name, atomic_read(&host->h_count),
host->h_inuse, host->h_expires);
}
}
}
}
/*
* 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(void)
{
struct hlist_head *chain;
struct hlist_node *pos, *next;
struct nlm_host *host;
dprintk("lockd: host garbage collection\n");
for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
hlist_for_each_entry(host, pos, chain, h_hash)
host->h_inuse = 0;
}
/* Mark all hosts that hold locks, blocks or shares */
nlmsvc_mark_resources();
for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
if (atomic_read(&host->h_count) || host->h_inuse
|| time_before(jiffies, host->h_expires)) {
dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
host->h_name, atomic_read(&host->h_count),
host->h_inuse, host->h_expires);
continue;
}
dprintk("lockd: delete host %s\n", host->h_name);
hlist_del_init(&host->h_hash);
nlm_destroy_host(host);
nrhosts--;
}
}
next_gc = jiffies + NLM_HOST_COLLECT;
}
/*
* Manage NSM handles
*/
static LIST_HEAD(nsm_handles);
static DEFINE_SPINLOCK(nsm_lock);
static struct nsm_handle *nsm_find(const struct sockaddr *sap,
const size_t salen,
const char *hostname,
const size_t hostname_len,
const int create)
{
struct nsm_handle *nsm = NULL;
struct nsm_handle *pos;
if (!sap)
return 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);
list_for_each_entry(pos, &nsm_handles, sm_link) {
if (hostname && nsm_use_hostnames) {
if (strlen(pos->sm_name) != hostname_len
|| memcmp(pos->sm_name, hostname, hostname_len))
continue;
} else if (!nlm_cmp_addr(nsm_addr(pos), sap))
continue;
atomic_inc(&pos->sm_count);
kfree(nsm);
nsm = pos;
goto found;
}
if (nsm) {
list_add(&nsm->sm_link, &nsm_handles);
goto found;
}
spin_unlock(&nsm_lock);
if (!create)
return NULL;
nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
if (nsm == NULL)
return NULL;
memcpy(nsm_addr(nsm), sap, salen);
nsm->sm_addrlen = salen;
nsm->sm_name = (char *) (nsm + 1);
memcpy(nsm->sm_name, hostname, hostname_len);
nsm->sm_name[hostname_len] = '\0';
nlm_display_address((struct sockaddr *)&nsm->sm_addr,
nsm->sm_addrbuf, sizeof(nsm->sm_addrbuf));
atomic_set(&nsm->sm_count, 1);
goto retry;
found:
spin_unlock(&nsm_lock);
return nsm;
}
/*
* Release an NSM handle
*/
void
nsm_release(struct nsm_handle *nsm)
{
if (!nsm)
return;
if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
list_del(&nsm->sm_link);
spin_unlock(&nsm_lock);
kfree(nsm);
}
}