Logo Search packages:      
Sourcecode: linux version File versions  Download package

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(utsname()->nodename);
      if (clnt->cl_nodelen > UNX_MAXNODENAME)
            clnt->cl_nodelen = UNX_MAXNODENAME;
      memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
      rpc_register_client(clnt);
      return clnt;

out_no_auth:
      if (!IS_ERR(clnt->cl_dentry)) {
            rpc_rmdir(clnt->cl_dentry);
            rpc_put_mount();
      }
out_no_path:
      rpc_free_iostats(clnt->cl_metrics);
out_no_stats:
      if (clnt->cl_server != clnt->cl_inline_name)
            kfree(clnt->cl_server);
      kfree(clnt);
out_err:
      xprt_put(xprt);
out_no_xprt:
      rpciod_down();
out_no_rpciod:
      return ERR_PTR(err);
}

/*
 * rpc_create - create an RPC client and transport with one call
 * @args: rpc_clnt create argument structure
 *
 * Creates and initializes an RPC transport and an RPC client.
 *
 * It can ping the server in order to determine if it is up, and to see if
 * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 * this behavior so asynchronous tasks can also use rpc_create.
 */
struct rpc_clnt *rpc_create(struct rpc_create_args *args)
{
      struct rpc_xprt *xprt;
      struct rpc_clnt *clnt;
      struct xprt_create xprtargs = {
            .ident = args->protocol,
            .srcaddr = args->saddress,
            .dstaddr = args->address,
            .addrlen = args->addrsize,
            .timeout = args->timeout
      };
      char servername[20];

      xprt = xprt_create_transport(&xprtargs);
      if (IS_ERR(xprt))
            return (struct rpc_clnt *)xprt;

      /*
       * If the caller chooses not to specify a hostname, whip
       * up a string representation of the passed-in address.
       */
      if (args->servername == NULL) {
            struct sockaddr_in *addr =
                              (struct sockaddr_in *) args->address;
            snprintf(servername, sizeof(servername), NIPQUAD_FMT,
                  NIPQUAD(addr->sin_addr.s_addr));
            args->servername = servername;
      }

      /*
       * By default, kernel RPC client connects from a reserved port.
       * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
       * but it is always enabled for rpciod, which handles the connect
       * operation.
       */
      xprt->resvport = 1;
      if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
            xprt->resvport = 0;

      clnt = rpc_new_client(xprt, args->servername, args->program,
                        args->version, args->authflavor);
      if (IS_ERR(clnt))
            return clnt;

      if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
            int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
            if (err != 0) {
                  rpc_shutdown_client(clnt);
                  return ERR_PTR(err);
            }
      }

      clnt->cl_softrtry = 1;
      if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
            clnt->cl_softrtry = 0;

      if (args->flags & RPC_CLNT_CREATE_INTR)
            clnt->cl_intr = 1;
      if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
            clnt->cl_autobind = 1;
      if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
            clnt->cl_discrtry = 1;

      return clnt;
}
EXPORT_SYMBOL_GPL(rpc_create);

/*
 * This function clones the RPC client structure. It allows us to share the
 * same transport while varying parameters such as the authentication
 * flavour.
 */
struct rpc_clnt *
rpc_clone_client(struct rpc_clnt *clnt)
{
      struct rpc_clnt *new;
      int err = -ENOMEM;

      new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
      if (!new)
            goto out_no_clnt;
      new->cl_parent = clnt;
      /* Turn off autobind on clones */
      new->cl_autobind = 0;
      INIT_LIST_HEAD(&new->cl_tasks);
      spin_lock_init(&new->cl_lock);
      rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
      new->cl_metrics = rpc_alloc_iostats(clnt);
      if (new->cl_metrics == NULL)
            goto out_no_stats;
      kref_init(&new->cl_kref);
      err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
      if (err != 0)
            goto out_no_path;
      if (new->cl_auth)
            atomic_inc(&new->cl_auth->au_count);
      xprt_get(clnt->cl_xprt);
      kref_get(&clnt->cl_kref);
      rpc_register_client(new);
      rpciod_up();
      return new;
out_no_path:
      rpc_free_iostats(new->cl_metrics);
out_no_stats:
      kfree(new);
out_no_clnt:
      dprintk("RPC:       %s: returned error %d\n", __FUNCTION__, err);
      return ERR_PTR(err);
}

/*
 * Properly shut down an RPC client, terminating all outstanding
 * requests.
 */
void rpc_shutdown_client(struct rpc_clnt *clnt)
{
      dprintk("RPC:       shutting down %s client for %s\n",
                  clnt->cl_protname, clnt->cl_server);

      while (!list_empty(&clnt->cl_tasks)) {
            rpc_killall_tasks(clnt);
            wait_event_timeout(destroy_wait,
                  list_empty(&clnt->cl_tasks), 1*HZ);
      }

      rpc_release_client(clnt);
}

/*
 * Free an RPC client
 */
static void
rpc_free_client(struct kref *kref)
{
      struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);

      dprintk("RPC:       destroying %s client for %s\n",
                  clnt->cl_protname, clnt->cl_server);
      if (!IS_ERR(clnt->cl_dentry)) {
            rpc_rmdir(clnt->cl_dentry);
            rpc_put_mount();
      }
      if (clnt->cl_parent != clnt) {
            rpc_release_client(clnt->cl_parent);
            goto out_free;
      }
      if (clnt->cl_server != clnt->cl_inline_name)
            kfree(clnt->cl_server);
out_free:
      rpc_unregister_client(clnt);
      rpc_free_iostats(clnt->cl_metrics);
      clnt->cl_metrics = NULL;
      xprt_put(clnt->cl_xprt);
      rpciod_down();
      kfree(clnt);
}

/*
 * Free an RPC client
 */
static void
rpc_free_auth(struct kref *kref)
{
      struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);

      if (clnt->cl_auth == NULL) {
            rpc_free_client(kref);
            return;
      }

      /*
       * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
       *       release remaining GSS contexts. This mechanism ensures
       *       that it can do so safely.
       */
      kref_init(kref);
      rpcauth_release(clnt->cl_auth);
      clnt->cl_auth = NULL;
      kref_put(kref, rpc_free_client);
}

/*
 * Release reference to the RPC client
 */
void
rpc_release_client(struct rpc_clnt *clnt)
{
      dprintk("RPC:       rpc_release_client(%p)\n", clnt);

      if (list_empty(&clnt->cl_tasks))
            wake_up(&destroy_wait);
      kref_put(&clnt->cl_kref, rpc_free_auth);
}

/**
 * rpc_bind_new_program - bind a new RPC program to an existing client
 * @old - old rpc_client
 * @program - rpc program to set
 * @vers - rpc program version
 *
 * Clones the rpc client and sets up a new RPC program. This is mainly
 * of use for enabling different RPC programs to share the same transport.
 * The Sun NFSv2/v3 ACL protocol can do this.
 */
struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
                              struct rpc_program *program,
                              u32 vers)
{
      struct rpc_clnt *clnt;
      struct rpc_version *version;
      int err;

      BUG_ON(vers >= program->nrvers || !program->version[vers]);
      version = program->version[vers];
      clnt = rpc_clone_client(old);
      if (IS_ERR(clnt))
            goto out;
      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;
      err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
      if (err != 0) {
            rpc_shutdown_client(clnt);
            clnt = ERR_PTR(err);
      }
out:
      return clnt;
}

/*
 * Default callback for async RPC calls
 */
static void
rpc_default_callback(struct rpc_task *task, void *data)
{
}

static const struct rpc_call_ops rpc_default_ops = {
      .rpc_call_done = rpc_default_callback,
};

/*
 *    Export the signal mask handling for synchronous code that
 *    sleeps on RPC calls
 */
#define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))

static void rpc_save_sigmask(sigset_t *oldset, int intr)
{
      unsigned long     sigallow = sigmask(SIGKILL);
      sigset_t sigmask;

      /* Block all signals except those listed in sigallow */
      if (intr)
            sigallow |= RPC_INTR_SIGNALS;
      siginitsetinv(&sigmask, sigallow);
      sigprocmask(SIG_BLOCK, &sigmask, oldset);
}

static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
{
      rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
}

static inline void rpc_restore_sigmask(sigset_t *oldset)
{
      sigprocmask(SIG_SETMASK, oldset, NULL);
}

void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
{
      rpc_save_sigmask(oldset, clnt->cl_intr);
}

void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
{
      rpc_restore_sigmask(oldset);
}

static
struct rpc_task *rpc_do_run_task(struct rpc_clnt *clnt,
            struct rpc_message *msg,
            int flags,
            const struct rpc_call_ops *ops,
            void *data)
{
      struct rpc_task *task, *ret;
      sigset_t oldset;

      task = rpc_new_task(clnt, flags, ops, data);
      if (task == NULL) {
            rpc_release_calldata(ops, data);
            return ERR_PTR(-ENOMEM);
      }

      /* Mask signals on synchronous RPC calls and RPCSEC_GSS upcalls */
      rpc_task_sigmask(task, &oldset);
      if (msg != NULL) {
            rpc_call_setup(task, msg, 0);
            if (task->tk_status != 0) {
                  ret = ERR_PTR(task->tk_status);
                  rpc_put_task(task);
                  goto out;
            }
      }
      atomic_inc(&task->tk_count);
      rpc_execute(task);
      ret = task;
out:
      rpc_restore_sigmask(&oldset);
      return ret;
}

/**
 * rpc_call_sync - Perform a synchronous RPC call
 * @clnt: pointer to RPC client
 * @msg: RPC call parameters
 * @flags: RPC call flags
 */
int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
{
      struct rpc_task   *task;
      int status;

      BUG_ON(flags & RPC_TASK_ASYNC);

      task = rpc_do_run_task(clnt, msg, flags, &rpc_default_ops, NULL);
      if (IS_ERR(task))
            return PTR_ERR(task);
      status = task->tk_status;
      rpc_put_task(task);
      return status;
}

/**
 * rpc_call_async - Perform an asynchronous RPC call
 * @clnt: pointer to RPC client
 * @msg: RPC call parameters
 * @flags: RPC call flags
 * @ops: RPC call ops
 * @data: user call data
 */
int
rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
             const struct rpc_call_ops *tk_ops, void *data)
{
      struct rpc_task   *task;

      task = rpc_do_run_task(clnt, msg, flags|RPC_TASK_ASYNC, tk_ops, data);
      if (IS_ERR(task))
            return PTR_ERR(task);
      rpc_put_task(task);
      return 0;
}

/**
 * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 * @clnt: pointer to RPC client
 * @flags: RPC flags
 * @ops: RPC call ops
 * @data: user call data
 */
struct rpc_task *rpc_run_task(struct rpc_clnt *clnt, int flags,
                              const struct rpc_call_ops *tk_ops,
                              void *data)
{
      return rpc_do_run_task(clnt, NULL, flags, tk_ops, data);
}
EXPORT_SYMBOL(rpc_run_task);

void
rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
{
      task->tk_msg   = *msg;
      task->tk_flags |= flags;
      /* Bind the user cred */
      if (task->tk_msg.rpc_cred != NULL)
            rpcauth_holdcred(task);
      else
            rpcauth_bindcred(task);

      if (task->tk_status == 0)
            task->tk_action = call_start;
      else
            task->tk_action = rpc_exit_task;
}

/**
 * rpc_peeraddr - extract remote peer address from clnt's xprt
 * @clnt: RPC client structure
 * @buf: target buffer
 * @size: length of target buffer
 *
 * Returns the number of bytes that are actually in the stored address.
 */
size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
{
      size_t bytes;
      struct rpc_xprt *xprt = clnt->cl_xprt;

      bytes = sizeof(xprt->addr);
      if (bytes > bufsize)
            bytes = bufsize;
      memcpy(buf, &clnt->cl_xprt->addr, bytes);
      return xprt->addrlen;
}
EXPORT_SYMBOL_GPL(rpc_peeraddr);

/**
 * rpc_peeraddr2str - return remote peer address in printable format
 * @clnt: RPC client structure
 * @format: address format
 *
 */
char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
{
      struct rpc_xprt *xprt = clnt->cl_xprt;

      if (xprt->address_strings[format] != NULL)
            return xprt->address_strings[format];
      else
            return "unprintable";
}
EXPORT_SYMBOL_GPL(rpc_peeraddr2str);

void
rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
{
      struct rpc_xprt *xprt = clnt->cl_xprt;
      if (xprt->ops->set_buffer_size)
            xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
}

/*
 * Return size of largest payload RPC client can support, in bytes
 *
 * For stream transports, this is one RPC record fragment (see RFC
 * 1831), as we don't support multi-record requests yet.  For datagram
 * transports, this is the size of an IP packet minus the IP, UDP, and
 * RPC header sizes.
 */
size_t rpc_max_payload(struct rpc_clnt *clnt)
{
      return clnt->cl_xprt->max_payload;
}
EXPORT_SYMBOL_GPL(rpc_max_payload);

/**
 * rpc_force_rebind - force transport to check that remote port is unchanged
 * @clnt: client to rebind
 *
 */
void rpc_force_rebind(struct rpc_clnt *clnt)
{
      if (clnt->cl_autobind)
            xprt_clear_bound(clnt->cl_xprt);
}
EXPORT_SYMBOL_GPL(rpc_force_rebind);

/*
 * Restart an (async) RPC call. Usually called from within the
 * exit handler.
 */
void
rpc_restart_call(struct rpc_task *task)
{
      if (RPC_ASSASSINATED(task))
            return;

      task->tk_action = call_start;
}

/*
 * 0.  Initial state
 *
 *     Other FSM states can be visited zero or more times, but
 *     this state is visited exactly once for each RPC.
 */
static void
call_start(struct rpc_task *task)
{
      struct rpc_clnt   *clnt = task->tk_client;

      dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
                  clnt->cl_protname, clnt->cl_vers,
                  task->tk_msg.rpc_proc->p_proc,
                  (RPC_IS_ASYNC(task) ? "async" : "sync"));

      /* Increment call count */
      task->tk_msg.rpc_proc->p_count++;
      clnt->cl_stats->rpccnt++;
      task->tk_action = call_reserve;
}

/*
 * 1. Reserve an RPC call slot
 */
static void
call_reserve(struct rpc_task *task)
{
      dprint_status(task);

      if (!rpcauth_uptodatecred(task)) {
            task->tk_action = call_refresh;
            return;
      }

      task->tk_status  = 0;
      task->tk_action  = call_reserveresult;
      xprt_reserve(task);
}

/*
 * 1b.      Grok the result of xprt_reserve()
 */
static void
call_reserveresult(struct rpc_task *task)
{
      int status = task->tk_status;

      dprint_status(task);

      /*
       * After a call to xprt_reserve(), we must have either
       * a request slot or else an error status.
       */
      task->tk_status = 0;
      if (status >= 0) {
            if (task->tk_rqstp) {
                  task->tk_action = call_allocate;
                  return;
            }

            printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
                        __FUNCTION__, status);
            rpc_exit(task, -EIO);
            return;
      }

      /*
       * Even though there was an error, we may have acquired
       * a request slot somehow.  Make sure not to leak it.
       */
      if (task->tk_rqstp) {
            printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
                        __FUNCTION__, status);
            xprt_release(task);
      }

      switch (status) {
      case -EAGAIN:     /* woken up; retry */
            task->tk_action = call_reserve;
            return;
      case -EIO:  /* probably a shutdown */
            break;
      default:
            printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
                        __FUNCTION__, status);
            break;
      }
      rpc_exit(task, status);
}

/*
 * 2. Allocate the buffer. For details, see sched.c:rpc_malloc.
 *    (Note: buffer memory is freed in xprt_release).
 */
static void
call_allocate(struct rpc_task *task)
{
      unsigned int slack = task->tk_msg.rpc_cred->cr_auth->au_cslack;
      struct rpc_rqst *req = task->tk_rqstp;
      struct rpc_xprt *xprt = task->tk_xprt;
      struct rpc_procinfo *proc = task->tk_msg.rpc_proc;

      dprint_status(task);

      task->tk_status = 0;
      task->tk_action = call_bind;

      if (req->rq_buffer)
            return;

      if (proc->p_proc != 0) {
            BUG_ON(proc->p_arglen == 0);
            if (proc->p_decode != NULL)
                  BUG_ON(proc->p_replen == 0);
      }

      /*
       * Calculate the size (in quads) of the RPC call
       * and reply headers, and convert both values
       * to byte sizes.
       */
      req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
      req->rq_callsize <<= 2;
      req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
      req->rq_rcvsize <<= 2;

      req->rq_buffer = xprt->ops->buf_alloc(task,
                              req->rq_callsize + req->rq_rcvsize);
      if (req->rq_buffer != NULL)
            return;

      dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);

      if (RPC_IS_ASYNC(task) || !signalled()) {
            task->tk_action = call_allocate;
            rpc_delay(task, HZ>>4);
            return;
      }

      rpc_exit(task, -ERESTARTSYS);
}

static inline int
rpc_task_need_encode(struct rpc_task *task)
{
      return task->tk_rqstp->rq_snd_buf.len == 0;
}

static inline void
rpc_task_force_reencode(struct rpc_task *task)
{
      task->tk_rqstp->rq_snd_buf.len = 0;
}

static inline void
rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
{
      buf->head[0].iov_base = start;
      buf->head[0].iov_len = len;
      buf->tail[0].iov_len = 0;
      buf->page_len = 0;
      buf->flags = 0;
      buf->len = 0;
      buf->buflen = len;
}

/*
 * 3. Encode arguments of an RPC call
 */
static void
call_encode(struct rpc_task *task)
{
      struct rpc_rqst   *req = task->tk_rqstp;
      kxdrproc_t  encode;
      __be32            *p;

      dprint_status(task);

      rpc_xdr_buf_init(&req->rq_snd_buf,
                   req->rq_buffer,
                   req->rq_callsize);
      rpc_xdr_buf_init(&req->rq_rcv_buf,
                   (char *)req->rq_buffer + req->rq_callsize,
                   req->rq_rcvsize);

      /* Encode header and provided arguments */
      encode = task->tk_msg.rpc_proc->p_encode;
      if (!(p = call_header(task))) {
            printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
            rpc_exit(task, -EIO);
            return;
      }
      if (encode == NULL)
            return;

      task->tk_status = rpcauth_wrap_req(task, encode, req, p,
                  task->tk_msg.rpc_argp);
      if (task->tk_status == -ENOMEM) {
            /* XXX: Is this sane? */
            rpc_delay(task, 3*HZ);
            task->tk_status = -EAGAIN;
      }
}

/*
 * 4. Get the server port number if not yet set
 */
static void
call_bind(struct rpc_task *task)
{
      struct rpc_xprt *xprt = task->tk_xprt;

      dprint_status(task);

      task->tk_action = call_connect;
      if (!xprt_bound(xprt)) {
            task->tk_action = call_bind_status;
            task->tk_timeout = xprt->bind_timeout;
            xprt->ops->rpcbind(task);
      }
}

/*
 * 4a.      Sort out bind result
 */
static void
call_bind_status(struct rpc_task *task)
{
      int status = -EIO;

      if (task->tk_status >= 0) {
            dprint_status(task);
            task->tk_status = 0;
            task->tk_action = call_connect;
            return;
      }

      switch (task->tk_status) {
      case -EAGAIN:
            dprintk("RPC: %5u rpcbind waiting for another request "
                        "to finish\n", task->tk_pid);
            /* avoid busy-waiting here -- could be a network outage. */
            rpc_delay(task, 5*HZ);
            goto retry_timeout;
      case -EACCES:
            dprintk("RPC: %5u remote rpcbind: RPC program/version "
                        "unavailable\n", task->tk_pid);
            /* fail immediately if this is an RPC ping */
            if (task->tk_msg.rpc_proc->p_proc == 0) {
                  status = -EOPNOTSUPP;
                  break;
            }
            rpc_delay(task, 3*HZ);
            goto retry_timeout;
      case -ETIMEDOUT:
            dprintk("RPC: %5u rpcbind request timed out\n",
                        task->tk_pid);
            goto retry_timeout;
      case -EPFNOSUPPORT:
            /* server doesn't support any rpcbind version we know of */
            dprintk("RPC: %5u remote rpcbind service unavailable\n",
                        task->tk_pid);
            break;
      case -EPROTONOSUPPORT:
            dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
                        task->tk_pid);
            task->tk_status = 0;
            task->tk_action = call_bind;
            return;
      default:
            dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
                        task->tk_pid, -task->tk_status);
      }

      rpc_exit(task, status);
      return;

retry_timeout:
      task->tk_action = call_timeout;
}

/*
 * 4b.      Connect to the RPC server
 */
static void
call_connect(struct rpc_task *task)
{
      struct rpc_xprt *xprt = task->tk_xprt;

      dprintk("RPC: %5u call_connect xprt %p %s connected\n",
                  task->tk_pid, xprt,
                  (xprt_connected(xprt) ? "is" : "is not"));

      task->tk_action = call_transmit;
      if (!xprt_connected(xprt)) {
            task->tk_action = call_connect_status;
            if (task->tk_status < 0)
                  return;
            xprt_connect(task);
      }
}

/*
 * 4c.      Sort out connect result
 */
static void
call_connect_status(struct rpc_task *task)
{
      struct rpc_clnt *clnt = task->tk_client;
      int status = task->tk_status;

      dprint_status(task);

      task->tk_status = 0;
      if (status >= 0) {
            clnt->cl_stats->netreconn++;
            task->tk_action = call_transmit;
            return;
      }

      /* Something failed: remote service port may have changed */
      rpc_force_rebind(clnt);

      switch (status) {
      case -ENOTCONN:
      case -EAGAIN:
            task->tk_action = call_bind;
            if (!RPC_IS_SOFT(task))
                  return;
            /* if soft mounted, test if we've timed out */
      case -ETIMEDOUT:
            task->tk_action = call_timeout;
            return;
      }
      rpc_exit(task, -EIO);
}

/*
 * 5. Transmit the RPC request, and wait for reply
 */
static void
call_transmit(struct rpc_task *task)
{
      dprint_status(task);

      task->tk_action = call_status;
      if (task->tk_status < 0)
            return;
      task->tk_status = xprt_prepare_transmit(task);
      if (task->tk_status != 0)
            return;
      task->tk_action = call_transmit_status;
      /* Encode here so that rpcsec_gss can use correct sequence number. */
      if (rpc_task_need_encode(task)) {
            BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
            call_encode(task);
            /* Did the encode result in an error condition? */
            if (task->tk_status != 0)
                  return;
      }
      xprt_transmit(task);
      if (task->tk_status < 0)
            return;
      /*
       * On success, ensure that we call xprt_end_transmit() before sleeping
       * in order to allow access to the socket to other RPC requests.
       */
      call_transmit_status(task);
      if (task->tk_msg.rpc_proc->p_decode != NULL)
            return;
      task->tk_action = rpc_exit_task;
      rpc_wake_up_task(task);
}

/*
 * 5a.      Handle cleanup after a transmission
 */
static void
call_transmit_status(struct rpc_task *task)
{
      task->tk_action = call_status;
      /*
       * Special case: if we've been waiting on the socket's write_space()
       * callback, then don't call xprt_end_transmit().
       */
      if (task->tk_status == -EAGAIN)
            return;
      xprt_end_transmit(task);
      rpc_task_force_reencode(task);
}

/*
 * 6. Sort out the RPC call status
 */
static void
call_status(struct rpc_task *task)
{
      struct rpc_clnt   *clnt = task->tk_client;
      struct rpc_rqst   *req = task->tk_rqstp;
      int         status;

      if (req->rq_received > 0 && !req->rq_bytes_sent)
            task->tk_status = req->rq_received;

      dprint_status(task);

      status = task->tk_status;
      if (status >= 0) {
            task->tk_action = call_decode;
            return;
      }

      task->tk_status = 0;
      switch(status) {
      case -EHOSTDOWN:
      case -EHOSTUNREACH:
      case -ENETUNREACH:
            /*
             * Delay any retries for 3 seconds, then handle as if it
             * were a timeout.
             */
            rpc_delay(task, 3*HZ);
      case -ETIMEDOUT:
            task->tk_action = call_timeout;
            if (task->tk_client->cl_discrtry)
                  xprt_disconnect(task->tk_xprt);
            break;
      case -ECONNREFUSED:
      case -ENOTCONN:
            rpc_force_rebind(clnt);
            task->tk_action = call_bind;
            break;
      case -EAGAIN:
            task->tk_action = call_transmit;
            break;
      case -EIO:
            /* shutdown or soft timeout */
            rpc_exit(task, status);
            break;
      default:
            printk("%s: RPC call returned error %d\n",
                         clnt->cl_protname, -status);
            rpc_exit(task, status);
      }
}

/*
 * 6a.      Handle RPC timeout
 *    We do not release the request slot, so we keep using the
 *    same XID for all retransmits.
 */
static void
call_timeout(struct rpc_task *task)
{
      struct rpc_clnt   *clnt = task->tk_client;

      if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
            dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
            goto retry;
      }

      dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
      task->tk_timeouts++;

      if (RPC_IS_SOFT(task)) {
            printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
                        clnt->cl_protname, clnt->cl_server);
            rpc_exit(task, -EIO);
            return;
      }

      if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
            task->tk_flags |= RPC_CALL_MAJORSEEN;
            printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
                  clnt->cl_protname, clnt->cl_server);
      }
      rpc_force_rebind(clnt);

retry:
      clnt->cl_stats->rpcretrans++;
      task->tk_action = call_bind;
      task->tk_status = 0;
}

/*
 * 7. Decode the RPC reply
 */
static void
call_decode(struct rpc_task *task)
{
      struct rpc_clnt   *clnt = task->tk_client;
      struct rpc_rqst   *req = task->tk_rqstp;
      kxdrproc_t  decode = task->tk_msg.rpc_proc->p_decode;
      __be32            *p;

      dprintk("RPC: %5u call_decode (status %d)\n",
                  task->tk_pid, task->tk_status);

      if (task->tk_flags & RPC_CALL_MAJORSEEN) {
            printk(KERN_NOTICE "%s: server %s OK\n",
                  clnt->cl_protname, clnt->cl_server);
            task->tk_flags &= ~RPC_CALL_MAJORSEEN;
      }

      if (task->tk_status < 12) {
            if (!RPC_IS_SOFT(task)) {
                  task->tk_action = call_bind;
                  clnt->cl_stats->rpcretrans++;
                  goto out_retry;
            }
            dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
                        clnt->cl_protname, task->tk_status);
            task->tk_action = call_timeout;
            goto out_retry;
      }

      /*
       * Ensure that we see all writes made by xprt_complete_rqst()
       * before it changed req->rq_received.
       */
      smp_rmb();
      req->rq_rcv_buf.len = req->rq_private_buf.len;

      /* Check that the softirq receive buffer is valid */
      WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
                        sizeof(req->rq_rcv_buf)) != 0);

      /* Verify the RPC header */
      p = call_verify(task);
      if (IS_ERR(p)) {
            if (p == ERR_PTR(-EAGAIN))
                  goto out_retry;
            return;
      }

      task->tk_action = rpc_exit_task;

      if (decode) {
            task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
                                          task->tk_msg.rpc_resp);
      }
      dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
                  task->tk_status);
      return;
out_retry:
      req->rq_received = req->rq_private_buf.len = 0;
      task->tk_status = 0;
      if (task->tk_client->cl_discrtry)
            xprt_disconnect(task->tk_xprt);
}

/*
 * 8. Refresh the credentials if rejected by the server
 */
static void
call_refresh(struct rpc_task *task)
{
      dprint_status(task);

      task->tk_action = call_refreshresult;
      task->tk_status = 0;
      task->tk_client->cl_stats->rpcauthrefresh++;
      rpcauth_refreshcred(task);
}

/*
 * 8a.      Process the results of a credential refresh
 */
static void
call_refreshresult(struct rpc_task *task)
{
      int status = task->tk_status;

      dprint_status(task);

      task->tk_status = 0;
      task->tk_action = call_reserve;
      if (status >= 0 && rpcauth_uptodatecred(task))
            return;
      if (status == -EACCES) {
            rpc_exit(task, -EACCES);
            return;
      }
      task->tk_action = call_refresh;
      if (status != -ETIMEDOUT)
            rpc_delay(task, 3*HZ);
      return;
}

/*
 * Call header serialization
 */
static __be32 *
call_header(struct rpc_task *task)
{
      struct rpc_clnt *clnt = task->tk_client;
      struct rpc_rqst   *req = task->tk_rqstp;
      __be32            *p = req->rq_svec[0].iov_base;

      /* FIXME: check buffer size? */

      p = xprt_skip_transport_header(task->tk_xprt, p);
      *p++ = req->rq_xid;           /* XID */
      *p++ = htonl(RPC_CALL);       /* CALL */
      *p++ = htonl(RPC_VERSION);    /* RPC version */
      *p++ = htonl(clnt->cl_prog);  /* program number */
      *p++ = htonl(clnt->cl_vers);  /* program version */
      *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
      p = rpcauth_marshcred(task, p);
      req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
      return p;
}

/*
 * Reply header verification
 */
static __be32 *
call_verify(struct rpc_task *task)
{
      struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
      int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
      __be32      *p = iov->iov_base;
      u32 n;
      int error = -EACCES;

      if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
            /* RFC-1014 says that the representation of XDR data must be a
             * multiple of four bytes
             * - if it isn't pointer subtraction in the NFS client may give
             *   undefined results
             */
            dprintk("RPC: %5u %s: XDR representation not a multiple of"
                   " 4 bytes: 0x%x\n", task->tk_pid, __FUNCTION__,
                   task->tk_rqstp->rq_rcv_buf.len);
            goto out_eio;
      }
      if ((len -= 3) < 0)
            goto out_overflow;
      p += 1;     /* skip XID */

      if ((n = ntohl(*p++)) != RPC_REPLY) {
            dprintk("RPC: %5u %s: not an RPC reply: %x\n",
                        task->tk_pid, __FUNCTION__, n);
            goto out_garbage;
      }
      if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
            if (--len < 0)
                  goto out_overflow;
            switch ((n = ntohl(*p++))) {
                  case RPC_AUTH_ERROR:
                        break;
                  case RPC_MISMATCH:
                        dprintk("RPC: %5u %s: RPC call version "
                                    "mismatch!\n",
                                    task->tk_pid, __FUNCTION__);
                        error = -EPROTONOSUPPORT;
                        goto out_err;
                  default:
                        dprintk("RPC: %5u %s: RPC call rejected, "
                                    "unknown error: %x\n",
                                    task->tk_pid, __FUNCTION__, n);
                        goto out_eio;
            }
            if (--len < 0)
                  goto out_overflow;
            switch ((n = ntohl(*p++))) {
            case RPC_AUTH_REJECTEDCRED:
            case RPC_AUTH_REJECTEDVERF:
            case RPCSEC_GSS_CREDPROBLEM:
            case RPCSEC_GSS_CTXPROBLEM:
                  if (!task->tk_cred_retry)
                        break;
                  task->tk_cred_retry--;
                  dprintk("RPC: %5u %s: retry stale creds\n",
                              task->tk_pid, __FUNCTION__);
                  rpcauth_invalcred(task);
                  /* Ensure we obtain a new XID! */
                  xprt_release(task);
                  task->tk_action = call_refresh;
                  goto out_retry;
            case RPC_AUTH_BADCRED:
            case RPC_AUTH_BADVERF:
                  /* possibly garbled cred/verf? */
                  if (!task->tk_garb_retry)
                        break;
                  task->tk_garb_retry--;
                  dprintk("RPC: %5u %s: retry garbled creds\n",
                              task->tk_pid, __FUNCTION__);
                  task->tk_action = call_bind;
                  goto out_retry;
            case RPC_AUTH_TOOWEAK:
                  printk(KERN_NOTICE "call_verify: server %s requires stronger "
                         "authentication.\n", task->tk_client->cl_server);
                  break;
            default:
                  dprintk("RPC: %5u %s: unknown auth error: %x\n",
                              task->tk_pid, __FUNCTION__, n);
                  error = -EIO;
            }
            dprintk("RPC: %5u %s: call rejected %d\n",
                        task->tk_pid, __FUNCTION__, n);
            goto out_err;
      }
      if (!(p = rpcauth_checkverf(task, p))) {
            dprintk("RPC: %5u %s: auth check failed\n",
                        task->tk_pid, __FUNCTION__);
            goto out_garbage;       /* bad verifier, retry */
      }
      len = p - (__be32 *)iov->iov_base - 1;
      if (len < 0)
            goto out_overflow;
      switch ((n = ntohl(*p++))) {
      case RPC_SUCCESS:
            return p;
      case RPC_PROG_UNAVAIL:
            dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
                        task->tk_pid, __FUNCTION__,
                        (unsigned int)task->tk_client->cl_prog,
                        task->tk_client->cl_server);
            error = -EPFNOSUPPORT;
            goto out_err;
      case RPC_PROG_MISMATCH:
            dprintk("RPC: %5u %s: program %u, version %u unsupported by "
                        "server %s\n", task->tk_pid, __FUNCTION__,
                        (unsigned int)task->tk_client->cl_prog,
                        (unsigned int)task->tk_client->cl_vers,
                        task->tk_client->cl_server);
            error = -EPROTONOSUPPORT;
            goto out_err;
      case RPC_PROC_UNAVAIL:
            dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
                        "version %u on server %s\n",
                        task->tk_pid, __FUNCTION__,
                        task->tk_msg.rpc_proc,
                        task->tk_client->cl_prog,
                        task->tk_client->cl_vers,
                        task->tk_client->cl_server);
            error = -EOPNOTSUPP;
            goto out_err;
      case RPC_GARBAGE_ARGS:
            dprintk("RPC: %5u %s: server saw garbage\n",
                        task->tk_pid, __FUNCTION__);
            break;                  /* retry */
      default:
            dprintk("RPC: %5u %s: server accept status: %x\n",
                        task->tk_pid, __FUNCTION__, n);
            /* Also retry */
      }

out_garbage:
      task->tk_client->cl_stats->rpcgarbage++;
      if (task->tk_garb_retry) {
            task->tk_garb_retry--;
            dprintk("RPC: %5u %s: retrying\n",
                        task->tk_pid, __FUNCTION__);
            task->tk_action = call_bind;
out_retry:
            return ERR_PTR(-EAGAIN);
      }
out_eio:
      error = -EIO;
out_err:
      rpc_exit(task, error);
      dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
                  __FUNCTION__, error);
      return ERR_PTR(error);
out_overflow:
      dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
                  __FUNCTION__);
      goto out_garbage;
}

static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
{
      return 0;
}

static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
{
      return 0;
}

static struct rpc_procinfo rpcproc_null = {
      .p_encode = rpcproc_encode_null,
      .p_decode = rpcproc_decode_null,
};

static int rpc_ping(struct rpc_clnt *clnt, int flags)
{
      struct rpc_message msg = {
            .rpc_proc = &rpcproc_null,
      };
      int err;
      msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
      err = rpc_call_sync(clnt, &msg, flags);
      put_rpccred(msg.rpc_cred);
      return err;
}

struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
{
      struct rpc_message msg = {
            .rpc_proc = &rpcproc_null,
            .rpc_cred = cred,
      };
      return rpc_do_run_task(clnt, &msg, flags, &rpc_default_ops, NULL);
}
EXPORT_SYMBOL(rpc_call_null);

#ifdef RPC_DEBUG
void rpc_show_tasks(void)
{
      struct rpc_clnt *clnt;
      struct rpc_task *t;

      spin_lock(&rpc_client_lock);
      if (list_empty(&all_clients))
            goto out;
      printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
            "-rpcwait -action- ---ops--\n");
      list_for_each_entry(clnt, &all_clients, cl_clients) {
            if (list_empty(&clnt->cl_tasks))
                  continue;
            spin_lock(&clnt->cl_lock);
            list_for_each_entry(t, &clnt->cl_tasks, tk_task) {
                  const char *rpc_waitq = "none";
                  int proc;

                  if (t->tk_msg.rpc_proc)
                        proc = t->tk_msg.rpc_proc->p_proc;
                  else
                        proc = -1;

                  if (RPC_IS_QUEUED(t))
                        rpc_waitq = rpc_qname(t->u.tk_wait.rpc_waitq);

                  printk("%5u %04d %04x %6d %8p %6d %8p %8ld %8s %8p %8p\n",
                        t->tk_pid, proc,
                        t->tk_flags, t->tk_status,
                        t->tk_client,
                        (t->tk_client ? t->tk_client->cl_prog : 0),
                        t->tk_rqstp, t->tk_timeout,
                        rpc_waitq,
                        t->tk_action, t->tk_ops);
            }
            spin_unlock(&clnt->cl_lock);
      }
out:
      spin_unlock(&rpc_client_lock);
}
#endif

Generated by  Doxygen 1.6.0   Back to index