path: root/net/sunrpc/clnt.c

/*
 *  linux/net/sunrpc/clnt.c
 *
 *  This file contains the high-level RPC interface.
 *  It is modeled as a finite state machine to support both synchronous
 *  and asynchronous requests.
 *
 *  -	RPC header generation and argument serialization.
 *  -	Credential refresh.
 *  -	TCP connect handling.
 *  -	Retry of operation when it is suspected the operation failed because
 *	of uid squashing on the server, or when the credentials were stale
 *	and need to be refreshed, or when a packet was damaged in transit.
 *	This may be have to be moved to the VFS layer.
 *
 *  NB: BSD uses a more intelligent approach to guessing when a request
 *  or reply has been lost by keeping the RTO estimate for each procedure.
 *  We currently make do with a constant timeout value.
 *
 *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
 *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
 */

#include <asm/system.h>

#include <linux/module.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/utsname.h>
#include <linux/workqueue.h>

#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
#include <linux/sunrpc/metrics.h>


#ifdef RPC_DEBUG
# define RPCDBG_FACILITY	RPCDBG_CALL
#endif

#define dprint_status(t)					\
	dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,		\
			__FUNCTION__, t->tk_status)

/*
 * All RPC clients are linked into this list
 */
static LIST_HEAD(all_clients);
static DEFINE_SPINLOCK(rpc_client_lock);

static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);


static void	call_start(struct rpc_task *task);
static void	call_reserve(struct rpc_task *task);
static void	call_reserveresult(struct rpc_task *task);
static void	call_allocate(struct rpc_task *task);
static void	call_encode(struct rpc_task *task);
static void	call_decode(struct rpc_task *task);
static void	call_bind(struct rpc_task *task);
static void	call_bind_status(struct rpc_task *task);
static void	call_transmit(struct rpc_task *task);
static void	call_status(struct rpc_task *task);
static void	call_transmit_status(struct rpc_task *task);
static void	call_refresh(struct rpc_task *task);
static void	call_refreshresult(struct rpc_task *task);
static void	call_timeout(struct rpc_task *task);
static void	call_connect(struct rpc_task *task);
static void	call_connect_status(struct rpc_task *task);
static __be32 *	call_header(struct rpc_task *task);
static __be32 *	call_verify(struct rpc_task *task);

static int	rpc_ping(struct rpc_clnt *clnt, int flags);

static void rpc_register_client(struct rpc_clnt *clnt)
{
	spin_lock(&rpc_client_lock);
	list_add(&clnt->cl_clients, &all_clients);
	spin_unlock(&rpc_client_lock);
}

static void rpc_unregister_client(struct rpc_clnt *clnt)
{
	spin_lock(&rpc_client_lock);
	list_del(&clnt->cl_clients);
	spin_unlock(&rpc_client_lock);
}

static int
rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
{
	static uint32_t clntid;
	int error;

	clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
	clnt->cl_dentry = ERR_PTR(-ENOENT);
	if (dir_name == NULL)
		return 0;

	clnt->cl_vfsmnt = rpc_get_mount();
	if (IS_ERR(clnt->cl_vfsmnt))
		return PTR_ERR(clnt->cl_vfsmnt);

	for (;;) {
		snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
				"%s/clnt%x", dir_name,
				(unsigned int)clntid++);
		clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
		clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
		if (!IS_ERR(clnt->cl_dentry))
			return 0;
		error = PTR_ERR(clnt->cl_dentry);
		if (error != -EEXIST) {
			printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
					clnt->cl_pathname, error);
			rpc_put_mount();
			return error;
		}
	}
}

static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
{
	struct rpc_version	*version;
	struct rpc_clnt		*clnt = NULL;
	struct rpc_auth		*auth;
	int err;
	size_t len;

	/* sanity check the name before trying to print it */
	err = -EINVAL;
	len = strlen(servname);
	if (len > RPC_MAXNETNAMELEN)
		goto out_no_rpciod;
	len++;

	dprintk("RPC:       creating %s client for %s (xprt %p)\n",
			program->name, servname, xprt);

	err = rpciod_up();
	if (err)
		goto out_no_rpciod;
	err = -EINVAL;
	if (!xprt)
		goto out_no_xprt;
	if (vers >= program->nrvers || !(version = program->version[vers]))
		goto out_err;

	err = -ENOMEM;
	clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
	if (!clnt)
		goto out_err;
	clnt->cl_parent = clnt;

	clnt->cl_server = clnt->cl_inline_name;
	if (len > sizeof(clnt->cl_inline_name)) {
		char *buf = kmalloc(len, GFP_KERNEL);
		if (buf != 0)
			clnt->cl_server = buf;
		else
			len = sizeof(clnt->cl_inline_name);
	}
	strlcpy(clnt->cl_server, servname, len);

	clnt->cl_xprt     = xprt;
	clnt->cl_procinfo = version->procs;
	clnt->cl_maxproc  = version->nrprocs;
	clnt->cl_protname = program->name;
	clnt->cl_prog     = program->number;
	clnt->cl_vers     = version->number;
	clnt->cl_stats    = program->stats;
	clnt->cl_metrics  = rpc_alloc_iostats(clnt);
	err = -ENOMEM;
	if (clnt->cl_metrics == NULL)
		goto out_no_stats;
	clnt->cl_program  = program;
	INIT_LIST_HEAD(&clnt->cl_tasks);
	spin_lock_init(&clnt->cl_lock);

	if (!xprt_bound(clnt->cl_xprt))
		clnt->cl_autobind = 1;

	clnt->cl_rtt = &clnt->cl_rtt_default;
	rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);

	kref_init(&clnt->cl_kref);

	err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
	if (err < 0)
		goto out_no_path;

	auth = rpcauth_create(flavor, clnt);
	if (IS_ERR(auth)) {
		printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
				flavor);
		err = PTR_ERR(auth);
		goto out_no_auth;
	}

	/* save the nodename */
	clnt->cl_nodelen = strlen(utsn