--- /dev/null
+/*
+ * 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/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 */
+};
+
+/*
+ * 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)
+ atomic_inc(&nsm->sm_count);
+ else {
+ host = NULL;
+ nsm = nsm_get_handle(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;
+ atomic_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;
+
+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);
+ 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
+ *
+ * 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)
+{
+ 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,
+ };
+ 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 (atomic_dec_and_test(&host->h_count)) {
+ WARN_ON_ONCE(!list_empty(&host->h_lockowners));
+ WARN_ON_ONCE(!list_empty(&host->h_granted));
+ WARN_ON_ONCE(!list_empty(&host->h_reclaim));
+
+ mutex_lock(&nlm_host_mutex);
+ 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++;
+
+ 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);
+ atomic_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) {
+ 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 = {
+ .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),
+ };
+
+ /*
+ * 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;
+}
+
+/*
+ * 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;
+}
+
+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
+ * @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 nlm_reboot *info)
+{
+ struct nsm_handle *nsm;
+ struct nlm_host *host;
+
+ nsm = nsm_reboot_lookup(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;
+ printk(KERN_WARNING "lockd: couldn't shutdown host module for net %p!\n", net);
+ dprintk("lockd: %lu hosts left in net %p:\n", ln->nrhosts, net);
+ } 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 %p)\n",
+ host->h_name, atomic_read(&host->h_count),
+ host->h_inuse, host->h_expires, host->net);
+ }
+}
+
+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 %p...\n", net);
+ 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;
+ }
+ }
+
+ /* Then, perform a garbage collection pass */
+ nlm_gc_hosts(net);
+ mutex_unlock(&nlm_host_mutex);
+
+ nlm_complain_hosts(net);
+}
+
+/*
+ * 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 %p\n", net);
+ 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 (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 net %p)\n",
+ host->h_name, atomic_read(&host->h_count),
+ host->h_inuse, host->h_expires, host->net);
+ continue;
+ }
+ nlm_destroy_host_locked(host);
+ }
+
+ if (net) {
+ struct lockd_net *ln = net_generic(net, lockd_net_id);
+
+ ln->next_gc = jiffies + NLM_HOST_COLLECT;
+ }
+}
Code Review / kvmfornfv.git / blobdiff