linux/fs/lockd/host.c

// 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 …
#define NLM_HOST_NRHASH …
#define NLM_HOST_REBIND …
#define NLM_HOST_EXPIRE …
#define NLM_HOST_COLLECT …

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) …

#define for_each_host_safe(host, next, chain, table) …

static unsigned long		nrhosts;
static DEFINE_MUTEX(nlm_host_mutex);

static void			nlm_gc_hosts(struct net *net);

struct nlm_lookup_host_info { … };

/*
 * Hash function must work well on big- and little-endian platforms
 */
static unsigned int __nlm_hash32(const __be32 n)
{ … }

static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
{ … }

static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
{ … }

static unsigned int nlm_hash_address(const struct sockaddr *sap)
{ … }

/*
 * 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)
{ … }

/*
 * Destroy an nlm_host and free associated resources
 *
 * Caller must hold nlm_host_mutex.
 */
static void nlm_destroy_host_locked(struct nlm_host *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
 * @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)
{ … }

/**
 * nlmclnt_release_host - release client nlm_host
 * @host: nlm_host to release
 *
 */
void nlmclnt_release_host(struct nlm_host *host)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/*
 * Create the NLM RPC client for an NLM peer
 */
struct rpc_clnt *
nlm_bind_host(struct nlm_host *host)
{ … }

/**
 * 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)
{ … }

/*
 * Increment NLM host count
 */
struct nlm_host * nlm_get_host(struct nlm_host *host)
{ … }

static struct nlm_host *next_host_state(struct hlist_head *cache,
					struct nsm_handle *nsm,
					const struct nlm_reboot *info)
{ … }

/**
 * 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)
{ … }

static void nlm_complain_hosts(struct net *net)
{ … }

void
nlm_shutdown_hosts_net(struct net *net)
{ … }

/*
 * Shut down the hosts module.
 * Note that this routine is called only at server shutdown time.
 */
void
nlm_shutdown_hosts(void)
{ … }

/*
 * 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)
{ … }