/* * 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/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); 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 */ const int noresvport; /* use non-priv port */ }; /* * 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); } /* * 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 (!rpc_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 (ni->server && !rpc_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_get_handle(ni->sap, ni->salen, ni->hostname, ni->hostname_len); 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; host->h_addrbuf = nsm->sm_addrbuf; memcpy(nlm_addr(host), ni->sap, ni->salen); host->h_addrlen = ni->salen; rpc_set_port(nlm_addr(host), 0); 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; host->h_noresvport = ni->noresvport; 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++; 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)); nsm_unmonitor(host); nsm_release(host->h_nsmhandle); 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 * @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) { 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), .noresvport = noresvport, }; 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)\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 = { .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; if (host->h_noresvport) args.flags |= RPC_CLNT_CREATE_NONPRIVPORT; 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)); } } } /** * 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 hlist_head *chain; struct hlist_node *pos; 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. */ 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 != info->state) { host->h_nsmstate = info->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); nsm_release(nsm); } /* * 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; }