path: root/nuttx/fs/nfs/rpc_clnt.c

/*
 * rpcclnt.c
 *
 * Copyright (c) 2004 The Regents of the University of Michigan.
 * All rights reserved.
 *
 * Copyright (c) 2004 Weston Andros Adamson <muzzle@umich.edu>.
 * Copyright (c) 2004 Marius Aamodt Eriksen <marius@umich.edu>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Copyright (c) 1989, 1991, 1993, 1995 The Regents of the University of
 * California.  All rights reserved.
 * 
 * This code is derived from software contributed to Berkeley by Rick Macklem at
 * The University of Guelph.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer. 2.
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution. 3. All advertising
 * materials mentioning features or use of this software must display the
 * following acknowledgement: This product includes software developed by the
 * University of California, Berkeley and its contributors. 4. Neither the
 * name of the University nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific
 * prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/socket.h>
#include <queue.h>
#include <time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <debug.h>

#include "xdr_subs.h"
#include "rpc_types.h"
#include "nfs_proto.h"
#include "nfs.h"
#include "rpc.h"
#include "rpc_clnt_private.h"
#include "rpc_v2.h"

#define RPC_RETURN(X) do { dbg("returning %d", X); return X; }while(0)

/*
 * Estimate rto for an nfs rpc sent via. an unreliable datagram. Use the mean
 * and mean deviation of rtt for the appropriate type of rpc for the frequent
 * rpcs and a default for the others. The justification for doing "other"
 * this way is that these rpcs happen so infrequently that timer est. would
 * probably be stale. Also, since many of these rpcs are non-idempotent, a
 * conservative timeout is desired. getattr, lookup - A+2D read, write     -
 * A+4D other           - nm_timeo
 */
#define RPC_RTO(n, t) \
        ((t) == 0 ? (n)->rc_timeo : \
         ((t) < 3 ? \
          (((((n)->rc_srtt[t-1] + 3) >> 2) + (n)->rc_sdrtt[t-1] + 1) >> 1) : \
          ((((n)->rc_srtt[t-1] + 7) >> 3) + (n)->rc_sdrtt[t-1] + 1)))

#define RPC_SRTT(s,r)   (r)->r_rpcclnt->rc_srtt[rpcclnt_proct((s),\
                                (r)->r_procnum) - 1]

#define RPC_SDRTT(s,r)  (r)->r_rpcclnt->rc_sdrtt[rpcclnt_proct((s),\
                                (r)->r_procnum) - 1]

/*
 * There is a congestion window for outstanding rpcs maintained per mount
 * point. The cwnd size is adjusted in roughly the way that: Van Jacobson,
 * Congestion avoidance and Control, In "Proceedings of SIGCOMM '88". ACM,
 * August 1988. describes for TCP. The cwnd size is chopped in half on a
 * retransmit timeout and incremented by 1/cwnd when each rpc reply is
 * received and a full cwnd of rpcs is in progress. (The sent count and cwnd
 * are scaled for integer arith.) Variants of "slow start" were tried and
 * were found to be too much of a performance hit (ave. rtt 3 times larger),
 * I suspect due to the large rtt that nfs rpcs have.
 */
#define RPC_CWNDSCALE   256
#define RPC_MAXCWND     (RPC_CWNDSCALE * 32)
static int rpcclnt_backoff[8] = { 2, 4, 8, 16, 32, 64, 128, 256, };

#define RPC_ERRSTR_ACCEPTED_SIZE 6
char *rpc_errstr_accepted[RPC_ERRSTR_ACCEPTED_SIZE] = {
  "",                           /* no good message... */
  "remote server hasn't exported program.",
  "remote server can't support version number.",
  "program can't support procedure.",
  "procedure can't decode params.",
  "remote error.  remote side memory allocation failure?"
};

char *rpc_errstr_denied[2] = {
  "remote server doesnt support rpc version 2!",
  "remote server authentication error."
};

#define RPC_ERRSTR_AUTH_SIZE 6
char *rpc_errstr_auth[RPC_ERRSTR_AUTH_SIZE] = {
  "",
  "auth error: bad credential (seal broken).",
  "auth error: client must begin new session.",
  "auth error: bad verifier (seal broken).",
  "auth error: verifier expired or replayed.",
  "auth error: rejected for security reasons.",
};

/*
 * Static data, mostly RPC constants in XDR form
 */
static uint32_t rpc_reply, rpc_call, rpc_vers, rpc_msgdenied,
  rpc_mismatch, rpc_auth_unix, rpc_msgaccepted, rpc_autherr, rpc_auth_null;

static uint32_t rpcclnt_xid = 0;
static uint32_t rpcclnt_xid_touched = 0;
struct rpcstats rpcstats;
int rpcclnt_ticks;
struct rpc_call *callmgs;
struct rpc_reply *replymsg;

/*
 * Queue head for rpctask's
 */
static dq_queue_t *rpctask_q;
//struct callout_handle rpcclnt_timer_handle; 

static int rpcclnt_send(struct socket *, struct sockaddr *, struct rpc_call *,
                        struct rpctask *);
static int rpcclnt_receive(struct rpctask *, struct sockaddr *,
                           struct rpc_reply *, struct rpc_call *);
static int rpcclnt_reply(struct rpctask *, struct rpc_call *,
                         struct rpc_reply *);
static void rpcclnt_timer(void *, struct rpc_call *);
#ifdef CONFIG_NFS_TCPIP
static int rpcclnt_sndlock(int *, struct rpctask *);
static void rpcclnt_sndunlock(int *);
static int rpcclnt_rcvlock(struct rpctask *);
static void rpcclnt_rcvunlock(int *);
#endif
static void rpcclnt_softterm(struct rpctask *task);

static uint32_t rpcclnt_proct(struct rpcclnt *, uint32_t);
static int rpcclnt_buildheader(struct rpcclnt *, int, int, struct rpc_call *);

void rpcclnt_init(void)
{
  rpcclnt_ticks = (CLOCKS_PER_SEC * RPC_TICKINTVL + 500) / 1000;
  if (rpcclnt_ticks < 1)
    rpcclnt_ticks = 1;
  rpcstats.rpcretries = 0;
  rpcstats.rpcrequests = 0;
  rpcstats.rpctimeouts = 0;
  rpcstats.rpcunexpected = 0;
  rpcstats.rpcinvalid = 0;

  /* 
   * rpc constants how about actually using more than one of these!
   */

  rpc_reply = txdr_unsigned(RPC_REPLY);
  rpc_vers = txdr_unsigned(RPC_VER2);
  rpc_call = txdr_unsigned(RPC_CALL);
  rpc_msgdenied = txdr_unsigned(RPC_MSGDENIED);
  rpc_msgaccepted = txdr_unsigned(RPC_MSGACCEPTED);
  rpc_mismatch = txdr_unsigned(RPC_MISMATCH);
  rpc_autherr = txdr_unsigned(RPC_AUTHERR);
  rpc_auth_unix = txdr_unsigned(RPCAUTH_UNIX);
  rpc_auth_null = txdr_unsigned(RPCAUTH_NULL);

  /* initialize rpctask queue */
  dq_init(rpctask_q);

  rpcclnt_timer(NULL, callmgs);

  printf("rpc initialed");
  return;
}

/*
void
rpcclnt_uninit(void)
{
        printf("uninit");
        untimeout(rpcclnt_timer, (void *)NULL, rpcclnt_timer_handle);

}
*/

/*
 * Initialize sockets and congestion for a new RPC connection. We do not free
 * the sockaddr if error.
 */
int rpcclnt_connect(struct rpcclnt *rpc)
{
  struct socket *so;
  int error;
  struct sockaddr *saddr;
  struct sockaddr_in *sin;
  struct timeval *tv;
  uint16_t tport;

  /* create the socket */
  rpc->rc_so = NULL;
  saddr = rpc->rc_name;
  rpc->rc_sotype = SOCK_DGRAM;

  error =
    psock_socket(saddr->sa_family, rpc->rc_sotype, rpc->rc_soproto, rpc->rc_so);

  if (error != 0)
    {
      printf("error %d in psock_socket()", error);
      RPC_RETURN(error);
    }

  so = rpc->rc_so;
  rpc->rc_soflags = so->s_flags;

  /* 
   * Some servers require that the client port be a reserved port
   * number. We always allocate a reserved port, as this prevents
   * filehandle disclosure through UDP port capture.
   */
  sin->sin_family = AF_INET;
  sin->sin_addr.s_addr = INADDR_ANY;
  tport = 1024;

  do
    {
      tport--;
      sin->sin_port = htons(tport);
      error = psock_bind(so, (struct sockaddr *)sin, sizeof(*sin));
    }
  while (error == EADDRINUSE && tport > 1024 / 2);

  if (error)
    {
      printf("bind failed\n");
      goto bad;
    }

  /* 
   * Protocols that do not require connections may be optionally left
   * unconnected for servers that reply from a port other than
   * NFS_PORT.
   */

#ifdef CONFIG_NFS_TCPIP
  if (rpc->rc_soflags == PR_CONNREQUIRED)
    {
      error = ENOTCONN;
      goto bad;

    }
  else
    {
#endif
      error = psock_connect(so, saddr, sizeof(*saddr));

      if (error)
        {
          dbg("psock_connect returns %d", error);
          goto bad;

        }

#ifdef CONFIG_NFS_TCPIP
    }
#endif

  /* 
   * Always set receive timeout to detect server crash and reconnect.
   * Otherwise, we can get stuck in psock_receive forever.
   */

  tv->tv_sec = 1;
  tv->tv_usec = 0;

  if ((error =
       psock_setsockopt(so, SOL_SOCKET, SO_RCVTIMEO, (const void *)tv,
                        sizeof(*tv))))
    {
      goto bad;
    }

  /* Initialize other non-zero congestion variables */
  rpc->rc_srtt[0] = rpc->rc_srtt[1] = rpc->rc_srtt[2] = rpc->rc_srtt[3] =
    rpc->rc_srtt[4] = (RPC_TIMEO << 3);
  rpc->rc_sdrtt[0] = rpc->rc_sdrtt[1] = rpc->rc_sdrtt[2] = rpc->rc_sdrtt[3] =
    rpc->rc_sdrtt[4] = 0;
  rpc->rc_cwnd = RPC_MAXCWND / 2;       /* Initial send window */
  rpc->rc_sent = 0;
  rpc->rc_timeouts = 0;

  RPC_RETURN(0);

bad:
  rpcclnt_disconnect(rpc);
  RPC_RETURN(error);
}

/*
 * Reconnect routine: Called when a connection is broken on a reliable
 * protocol. - clean up the old socket - nfs_connect() again - set
 * TASK_MUSTRESEND for all outstanding requests on mount point If this
 * fails the mount point is DEAD! nb: Must be called with the
 * nfs_sndlock() set on the mount point.
 */
int rpcclnt_reconnect(struct rpctask *rep)
{
  struct rpctask *rp;
  struct rpcclnt *rpc = rep->r_rpcclnt;
  int error;

  rpcclnt_disconnect(rpc);
  while ((error = rpcclnt_connect(rpc)) != 0)
    {
      if (error == EINTR || error == ERESTART)
        return (EINTR);
    }

  /* 
   * Loop through outstanding request list and fix up all
   * requests on old socket.
   */
  for (rp = (struct rpctask *)rpctask_q->head; rp != NULL;
       rp = (struct rpctask *)rp->r_chain.blink)
    {
      if (rp->r_rpcclnt == rpc)
        rp->r_flags |= TASK_MUSTRESEND;
    }
  return (0);
}

void rpcclnt_disconnect(struct rpcclnt *rpc)
{
  struct socket *so;

  if (rpc->rc_so != NULL)
    {
      so = rpc->rc_so;
      rpc->rc_so = NULL;
      (void)psock_close(so);
    }
}

#ifdef CONFIG_NFS_TCPIP
void rpcclnt_safedisconnect(struct rpcclnt *rpc)
{
  struct rpctask dummytask;

  memset((void *)dummytask, 0, sizeof(*call));
  dummytask.r_rpcclnt = rpc;
  rpcclnt_rcvlock(&dummytask);
  rpcclnt_disconnect(rpc);
  rpcclnt_rcvunlock(&rpc->rc_flag);
}

#endif

/*
 * This is the nfs send routine. For connection based socket types, it must
 * be called with an nfs_sndlock() on the socket. "rep == NULL" indicates
 * that it has been called from a server. For the client side: - return EINTR
 * if the RPC is terminated, 0 otherwise - set TASK_MUSTRESEND if the send fails
 * for any reason - do any cleanup required by recoverable socket errors
 * (???) For the server side: - return EINTR or ERESTART if interrupted by a
 * signal - return EPIPE if a connection is lost for connection based sockets
 * (TCP...) - do any cleanup required by recoverable socket errors (???)
 */
static int
rpcclnt_send(struct socket *so, struct sockaddr *nam, struct rpc_call *call,
             struct rpctask *rep)
{
  struct sockaddr *sendnam;
  int error, soflags, flags;

  if (rep != NULL)
    {
      if (rep->r_flags & TASK_SOFTTERM)
        {
          RPC_RETURN(EINTR);
        }
      if ((so = rep->r_rpcclnt->rc_so) == NULL)
        {
          rep->r_flags |= TASK_MUSTRESEND;
          RPC_RETURN(0);
        }
      rep->r_flags &= ~TASK_MUSTRESEND;
      soflags = rep->r_rpcclnt->rc_soflags;
    }
  else
    soflags = so->s_flags;
#ifdef CONFIG_NFS_TCPIP
  if ((soflags & PR_CONNREQUIRED))
    sendnam = NULL;
  else
#endif
    sendnam = nam;

  if (so->s_type == SOCK_SEQPACKET)
    flags = MSG_EOR;
  else
    flags = 0;

  error =
    psock_sendto(so, call, sizeof(*call), flags, sendnam, sizeof(*sendnam));

  if (error != 0)
    {
      if (rep != NULL)
        {
          printf("rpc send error %d for service %s\n", error,
                 rep->r_rpcclnt->rc_prog->prog_name);
          /* 
           * Deal with errors for the client side.
           */
          if (rep->r_flags & TASK_SOFTTERM)
            error = EINTR;
          else
            rep->r_flags |= TASK_MUSTRESEND;
        }
      else
        printf("rpc service send error %d\n", error);

      /* 
       * Handle any recoverable (soft) socket errors here.
       */
      if (error != EINTR && error != ERESTART &&
          error != EWOULDBLOCK && error != EPIPE)
        error = 0;
    }

  RPC_RETURN(error);
}

/*
 * Receive a Sun RPC Request/Reply. For SOCK_DGRAM, the work is all
 * done by soreceive().For SOCK_STREAM, first get the
 * Record Mark to find out how much more there is to get. We must
 * lock the socket against other receivers until we have an entire
 * rpc request/reply.
 */
static int rpcclnt_receive(struct rpctask *rep, struct sockaddr *aname,
                           struct rpc_reply *reply, struct rpc_call *call)
{
  struct socket *so;
#ifdef CONFIG_NFS_TCPIP
  uint32_t len;
#endif
  int error, sotype, rcvflg;

  /* 
   * Set up arguments for soreceive()
   */

  sotype = rep->r_rpcclnt->rc_sotype;

  /* 
   * For reliable protocols, lock against other senders/receivers in
   * case a reconnect is necessary. For SOCK_STREAM, first get the
   * Record Mark to find out how much more there is to get. We must
   * lock the socket against other receivers until we have an entire
   * rpc request/reply.
   */
#ifdef CONFIG_NFS_TCPIP
  if (sotype != SOCK_DGRAM)
    {
      error = rpcclnt_sndlock(&rep->r_rpcclnt->rc_flag, rep);
      if (error != 0)
        return (error);
    tryagain:
      /* 
       * Check for fatal errors and resending request.
       */
      /* 
       * Ugh: If a reconnect attempt just happened, rc_so would
       * have changed. NULL indicates a failed attempt that has
       * essentially shut down this mount point.
       */
      if (rep->r_flags & TASK_SOFTTERM)
        {
          rpcclnt_sndunlock(&rep->r_rpcclnt->rc_flag);
          return (EINTR);
        }
      so = rep->r_rpcclnt->rc_so;
      if (so == NULL)
        {
          error = rpcclnt_reconnect(rep);
          if (error)
            {
              rpcclnt_sndunlock(&rep->r_rpcclnt->rc_flag);
              return (error);
            }
          goto tryagain;
        }
      while (rep->r_flags & TASK_MUSTRESEND)
        {
          rpcstats.rpcretries++;
          error = rpcclnt_send(so, rep->r_rpcclnt->rc_name, call, rep);
          if (error)
            {
              if (error == EINTR || error == ERESTART ||
                  (error = rpcclnt_reconnect(rep)) != 0)
                {
                  rpcclnt_sndunlock(&rep->r_rpcclnt->rc_flag);
                  return (error);
                }
              goto tryagain;
            }
        }

      rpcclnt_sndunlock(&rep->r_rpcclnt->rc_flag);
      if (sotype == SOCK_STREAM)
        {
          do
            {
              rcvflg = MSG_WAITALL;
              error = psock_recvfrom(so, reply, sizeof(*reply),
                                     &rcvflg, rep->r_rpcclnt->rc_name,
                                     sizeof(*rep->r_rpcclnt->rc_name));
              if (error == EWOULDBLOCK && rep && (rep->r_flags & TASK_SOFTTERM))
                RPC_RETURN(EINTR);
            }
          while (error == EWOULDBLOCK);

          if (error == 0)
            {
              printf("short receive from rpc server %s\n",
                     rep->r_rpcclnt->rc_prog->prog_name);
              error = EPIPE;
            }

          len = ntohl(len) & ~0x80000000;
          /* 
           * This is SERIOUS! We are out of sync with the
           * sender and forcing a disconnect/reconnect is all I
           * can do.
           */
          if (len > RPC_MAXPACKET)
            {
              printf("%s (%d) from rpc server %s\n",
                     "impossible packet length",
                     len, rep->r_rpcclnt->rc_prog->prog_name);
              error = EFBIG;
              goto errout;
            }
          do
            {
              rcvflg = MSG_WAITALL;
              error = psock_recvfrom(so, reply, sizeof(*reply),
                                     &rcvflg, rep->r_rpcclnt->rc_name,
                                     sizeof(*rep->r_rpcclnt->rc_name));
            }
          while (error == EWOULDBLOCK || error == EINTR || error == ERESTART);

          if (error == 0)
            {
              printf("short receive from rpc server %s\n",
                     rep->r_rpcclnt->rc_prog->prog_name);
              error = EPIPE;
            }

          if (error != 0)
            goto errout;

        }
      else
        {
          /* 
           * NB: Since uio_resid is big, MSG_WAITALL is ignored
           * and soreceive() will return when it has either a
           * control msg or a data msg. We have no use for
           * control msg., but must grab them and then throw
           * them away so we know what is going on.
           */
          do
            {
              rcvflg = 0;
              error = psock_recvfrom(so, reply, sizeof(*reply),
                                     &rcvflg, rep->r_rpcclnt->rc_name,
                                     sizeof(*rep->r_rpcclnt->rc_name));
              if (error == EWOULDBLOCK && rep)
                {
                  if (rep->r_flags & TASK_SOFTTERM)
                    {
                      return (EINTR);
                    }
                }
            }
          while (error == EWOULDBLOCK || (!error));

          if ((rcvflg & MSG_EOR) == 0)
            printf("Egad!!\n");
          if (error == 0)
            error = EPIPE;
        }

    errout:
      if (error != 0 && error != EINTR && error != ERESTART)
        {
          if (error != EPIPE)
            printf("receive error %d from rpc server %s\n",
                   error, rep->r_rpcclnt->rc_prog->prog_name);
          error = rpcclnt_sndlock(&rep->r_rpcclnt->rc_flag, rep);
          if (error == 0)
            error = rpcclnt_reconnect(rep);
          if (error == 0)
            goto tryagain;
        }
    }
  else
    {
#endif
      if ((so = rep->r_rpcclnt->rc_so) == NULL)
        RPC_RETURN(EACCES);

      do
        {
          rcvflg = 0;
          error =
            psock_recvfrom(so, reply, sizeof(*reply), rcvflg, aname,
                           (socklen_t *) sizeof(*aname));
          dbg("psock_recvfrom returns %d", error);
          if (error == EWOULDBLOCK && (rep->r_flags & TASK_SOFTTERM))
            {
              dbg("wouldblock && softerm -> EINTR");
              RPC_RETURN(EINTR);
            }
        }
      while (error == EWOULDBLOCK);

#ifdef CONFIG_NFS_TCPIP
    }
#endif
  RPC_RETURN(error);
}

/*
 * Implement receipt of reply on a socket. We must search through the list of
 * received datagrams matching them with outstanding requests using the xid,
 * until ours is found.
 */

/* ARGSUSED */
static int
rpcclnt_reply(struct rpctask *myrep, struct rpc_call *call,
              struct rpc_reply *reply)
{
  struct rpctask *rep;
  struct rpcclnt *rpc = myrep->r_rpcclnt;
  int32_t t1;
  struct sockaddr *nam;
  uint32_t rxid;
  int error;

  /* 
   * Loop around until we get our own reply
   */
  for (;;)
    {
      /* 
       * Lock against other receivers so that I don't get stuck in
       * sbwait() after someone else has received my reply for me.
       * Also necessary for connection based protocols to avoid
       * race conditions during a reconnect.
       */
#ifdef CONFIG_NFS_TCPIP
      error = rpcclnt_rcvlock(myrep);
      if (error)
        return (error);
#endif
      /* 
       * Get the next Rpc reply off the socket
       */
      error = rpcclnt_receive(myrep, nam, reply, call);

#ifdef CONFIG_NFS_TCPIP
      rpcclnt_rcvunlock(&rpc->rc_flag);
#endif

      if (error != 0)
        {
          /* 
           * Ignore routing errors on connectionless
           * protocols??
           */
          if (RPCIGNORE_SOERROR(rpc->rc_soflags, error))
            {
              if (myrep->r_flags & TASK_GETONEREP)
                RPC_RETURN(0);
              dbg("ingoring routing error on connectionless protocol.");
              continue;
            }
          RPC_RETURN(error);
        }

      /* 
       * Get the xid and check that it is an rpc reply
       */
      rxid = reply->rp_xid;
      if (reply->rp_direction != rpc_reply)
        {
          rpcstats.rpcinvalid++;
          if (myrep->r_flags & TASK_GETONEREP)
            RPC_RETURN(0);
          continue;
        }
      /* 
       * Loop through the request list to match up the reply Iff no
       * match, just drop the datagram
       */
      for (rep = (struct rpctask *)rpctask_q->head; rep;
           rep = (struct rpctask *)rep->r_chain.flink)
        {
          if (rxid == rep->r_xid)
            {
              /* 
               * Update congestion window. Do the additive
               * increase of one rpc/rtt.
               */
              if (rpc->rc_cwnd <= rpc->rc_sent)
                {
                  rpc->rc_cwnd +=
                    (RPC_CWNDSCALE * RPC_CWNDSCALE +
                     (rpc->rc_cwnd >> 1)) / rpc->rc_cwnd;
                  if (rpc->rc_cwnd > RPC_MAXCWND)
                    rpc->rc_cwnd = RPC_MAXCWND;
                }

              rep->r_flags &= ~TASK_SENT;
              rpc->rc_sent -= RPC_CWNDSCALE;

              /* 
               * Update rtt using a gain of 0.125 on the
               * mean and a gain of 0.25 on the deviation.
               */
              if (rep->r_flags & TASK_TIMING)
                {
                  /* 
                   * Since the timer resolution of
                   * NFS_HZ is so course, it can often
                   * result in r_rtt == 0. Since r_rtt
                   * == N means that the actual rtt is
                   * between N+dt and N+2-dt ticks, add
                   * 1.
                   */
                  t1 = rep->r_rtt + 1;
                  t1 -= (RPC_SRTT(rpc, rep) >> 3);
                  RPC_SRTT(rpc, rep) += t1;
                  if (t1 < 0)
                    t1 = -t1;
                  t1 -= (RPC_SDRTT(rpc, rep) >> 2);
                  RPC_SDRTT(rpc, rep) += t1;
                }
              rpc->rc_timeouts = 0;
              break;
            }
        }
      /* 
       * If not matched to a request, drop it. If it's mine, get
       * out.
       */
      if (rep == 0)
        {
          rpcstats.rpcunexpected++;
          dbg("rpc reply not matched\n");
        }
      else if (rep == myrep)
        {
          RPC_RETURN(0);
        }
      if (myrep->r_flags & TASK_GETONEREP)
        RPC_RETURN(0);
    }
}

/* XXX: ignores tryagain! */

/*
 * code from nfs_request - goes something like this - fill in task struct -
 * links task into list - calls nfs_send() for first transmit - calls
 * nfs_receive() to get reply - fills in reply (which should be initialized
 * prior to calling), which is valid when 0 is returned and is NEVER freed in
 * this function
 * 
 * always frees the request header, but NEVER frees 'mrest'
 * 
 */

/*
 * note that reply->result_* are invalid unless reply->type ==
 * RPC_MSGACCEPTED and reply->status == RPC_SUCCESS and that reply->verf_*
 * are invalid unless reply->type == RPC_MSGACCEPTED
 */
int rpcclnt_request(struct rpcclnt *rpc, int procnum, struct rpc_reply *reply)
{
  struct rpc_call *call;
  struct rpc_reply *replysvr;
  struct rpctask *task, _task;
  int error = 0;
  int xid;

  task = &_task;
  memset(task, 0, sizeof(*task));

  task->r_rpcclnt = rpc;
  task->r_procnum = procnum;

  error = rpcclnt_buildheader(rpc, procnum, xid, call);
  if (error)
    {
      printf("building call header error");
      goto rpcmout;
    }

  task->r_xid = fxdr_unsigned(uint32_t, xid);

  if (rpc->rc_flag & RPCCLNT_SOFT)
    task->r_retry = rpc->rc_retry;
  else
    task->r_retry = RPC_MAXREXMIT + 1;  /* past clip limit */
  task->r_rtt = task->r_rexmit = 0;

  if (rpcclnt_proct(rpc, procnum) > 0)
    task->r_flags = TASK_TIMING;
  else
    task->r_flags = 0;

  /* 
   * Do the client side RPC.
   */
  rpcstats.rpcrequests++;

  /* 
   * Chain request into list of outstanding requests. Be sure to put it
   * LAST so timer finds oldest requests first.
   */
  dq_addlast(&task->r_chain, rpctask_q);

  /* 
   * If backing off another request or avoiding congestion, don't send
   * this one now but let timer do it. If not timing a request, do it
   * now.
   */
  if (rpc->rc_so && (rpc->rc_sotype != SOCK_DGRAM ||
                     (rpc->rc_flag & RPCCLNT_DUMBTIMR) ||
                     rpc->rc_sent < rpc->rc_cwnd))
    {

#ifdef CONFIG_NFS_TCPIP
      if (rpc->rc_soflags & PR_CONNREQUIRED)
        error = rpcclnt_sndlock(&rpc->rc_flag, task);
#endif

      if (error == 0)
        {
          error = rpcclnt_send(rpc->rc_so, rpc->rc_name, call, task);

#ifdef CONFIG_NFS_TCPIP
          if (rpc->rc_soflags & PR_CONNREQUIRED)
            rpcclnt_sndunlock(&rpc->rc_flag);
#endif
        }
      if (error == 0 && (task->r_flags & TASK_MUSTRESEND) == 0)
        {
          rpc->rc_sent += RPC_CWNDSCALE;
          task->r_flags |= TASK_SENT;
        }
    }
  else
    {
      task->r_rtt = -1;
    }

  /* 
   * Wait for the reply from our send.
   */
  if (error == 0 || error == EPIPE)
    error = rpcclnt_reply(task, call, replysvr);

  /* 
   * RPC done, unlink the request.
   */
  dq_rem(&task->r_chain, rpctask_q);

  /* 
   * Decrement the outstanding request count.
   */
  if (task->r_flags & TASK_SENT)
    {
      task->r_flags &= ~TASK_SENT;      /* paranoia */
      rpc->rc_sent -= RPC_CWNDSCALE;
    }

  if (error != 0)
    goto rpcmout;

  /* 
   * break down the rpc header and check if ok
   */
  reply->stat.type = fxdr_unsigned(uint32_t, replysvr->stat.type);
  if (reply->stat.type == RPC_MSGDENIED)
    {
      reply->stat.status = fxdr_unsigned(uint32_t, replysvr->stat.status);
      switch (reply->stat.status)
        {
        case RPC_MISMATCH:
          reply->stat.mismatch_info.low =
            fxdr_unsigned(uint32_t, replysvr->stat.mismatch_info.low);
          reply->stat.mismatch_info.high =
            fxdr_unsigned(uint32_t, replysvr->stat.mismatch_info.high);
          printf("RPC_MSGDENIED: RPC_MISMATCH error");
          error = EOPNOTSUPP;
          break;
        case RPC_AUTHERR:
          reply->stat.autherr = fxdr_unsigned(uint32_t, replysvr->stat.autherr);
          printf("RPC_MSGDENIED: RPC_AUTHERR error");
          error = EACCES;
          break;
        default:
          error = EOPNOTSUPP;
          break;
        }
      goto rpcmout;
    }
  else if (reply->stat.type != RPC_MSGACCEPTED)
    {
      error = EOPNOTSUPP;
      goto rpcmout;
    }

  /* Verifier */

  reply->rpc_verfi.authtype =
    fxdr_unsigned(uint32_t, replysvr->rpc_verfi.authtype);
  reply->rpc_verfi.authlen =
    fxdr_unsigned(uint32_t, replysvr->rpc_verfi.authlen);

  if (reply->stat.status == RPC_SUCCESS)
    {
      printf("RPC_SUCCESS");
    }
  else if (reply->stat.status == RPC_PROGMISMATCH)
    {
      reply->stat.mismatch_info.low =
        fxdr_unsigned(uint32_t, replysvr->stat.mismatch_info.low);
      reply->stat.mismatch_info.high =
        fxdr_unsigned(uint32_t, replysvr->stat.mismatch_info.high);
      printf("RPC_MSGACCEPTED: RPC_PROGMISMATCH error");
      error = EOPNOTSUPP;       /* XXXMARIUS */
    }
  else if (reply->stat.status > 5)
    {
      error = EOPNOTSUPP;
      goto rpcmout;
    }

rpcmout:
  RPC_RETURN(error);
}

/*
 * Nfs timer routine Scan the nfsreq list and retranmit any requests that
 * have timed out To avoid retransmission attempts on STREAM sockets (in the
 * future) make sure to set the r_retry field to 0 (implies nm_retry == 0).
 */
void rpcclnt_timer(void *arg, struct rpc_call *call)
{
  struct rpctask *rep;
  struct socket *so;
  struct rpcclnt *rpc;
  int timeo, error;

  for (rep = (struct rpctask *)rpctask_q->head; rep;
       rep = (struct rpctask *)rep->r_chain.flink)
    {
      rpc = rep->r_rpcclnt;
      if (rep->r_flags & TASK_SOFTTERM)
        continue;
      if (rep->r_rtt >= 0)
        {
          rep->r_rtt++;
          if (rpc->rc_flag & RPCCLNT_DUMBTIMR)
            timeo = rpc->rc_timeo;
          else
            timeo = RPC_RTO(rpc, rpcclnt_proct(rep->r_rpcclnt, rep->r_procnum));
          if (rpc->rc_timeouts > 0)
            timeo *= rpcclnt_backoff[rpc->rc_timeouts - 1];
          if (rep->r_rtt <= timeo)
            continue;
          if (rpc->rc_timeouts < 8)
            rpc->rc_timeouts++;
        }
      /* 
       * Check for server not responding
       */
      if ((rep->r_flags & TASK_TPRINTFMSG) == 0 &&
          rep->r_rexmit > rpc->rc_deadthresh)
        {
          printf("Server is not responding");
          rep->r_flags |= TASK_TPRINTFMSG;
        }
      if (rep->r_rexmit >= rep->r_retry)
        {                       /* too many */
          rpcstats.rpctimeouts++;
          rep->r_flags |= TASK_SOFTTERM;
          continue;
        }
      if (rpc->rc_sotype != SOCK_DGRAM)
        {
          if (++rep->r_rexmit > RPC_MAXREXMIT)
            rep->r_rexmit = RPC_MAXREXMIT;
          continue;
        }
      if ((so = rpc->rc_so) == NULL)
        continue;

      /* 
       * If there is enough space and the window allows.. Resend it
       * Set r_rtt to -1 in case we fail to send it now.
       */
      rep->r_rtt = -1;
      if ((rpc->rc_flag & RPCCLNT_DUMBTIMR) || (rep->r_flags & TASK_SENT) ||
          rpc->rc_sent < rpc->rc_cwnd)
        {

          if ((rpc->rc_flag & RPCCLNT_NOCONN) == 0)
            error = psock_sendto(so, call, sizeof(*call), 0, NULL, 0);
          else
            error =
              psock_sendto(so, call, sizeof(*call), 0, rpc->rc_name,
                           sizeof(*rpc->rc_name));

          if (!error)
            {
              /* 
               * Iff first send, start timing else turn
               * timing off, backoff timer and divide
               * congestion window by 2.
               */
              if (rep->r_flags & TASK_SENT)
                {
                  rep->r_flags &= ~TASK_TIMING;
                  if (++rep->r_rexmit > RPC_MAXREXMIT)
                    rep->r_rexmit = RPC_MAXREXMIT;
                  rpc->rc_cwnd >>= 1;
                  if (rpc->rc_cwnd < RPC_CWNDSCALE)
                    rpc->rc_cwnd = RPC_CWNDSCALE;
                  rpcstats.rpcretries++;
                }
              else
                {
                  rep->r_flags |= TASK_SENT;
                  rpc->rc_sent += RPC_CWNDSCALE;
                }
              rep->r_rtt = 0;
            }
        }
    }

  // rpcclnt_timer_handle = timeout(rpcclnt_timer, NULL, rpcclnt_ticks);
}

#ifdef CONFIG_NFS_TCPIP

/*
 * Lock a socket against others. Necessary for STREAM sockets to ensure you
 * get an entire rpc request/reply and also to avoid race conditions between
 * the processes with nfs requests in progress when a reconnect is necessary.
 */
static int rpcclnt_sndlock(flagp, task)
     int *flagp;
     struct rpctask *task;
{
  int slpflag = 0, slptimeo = 0;

  if (task)
    {
      if (task->r_rpcclnt->rc_flag & RPCCLNT_INT)
        slpflag = PCATCH;
    }
  while (*flagp & RPCCLNT_SNDLOCK)
    {
      if (rpcclnt_sigintr(task->r_rpcclnt, task, p))
        return (EINTR);
      *flagp |= RPCCLNT_WANTSND;
      if (slpflag == PCATCH)
        {
          slpflag = 0;
          slptimeo = 2 * CLOCKS_PER_SEC;
        }
    }

  *flagp |= RPCCLNT_SNDLOCK;
  return (0);
}

/*
 * Unlock the stream socket for others.
 */
static void rpcclnt_sndunlock(flagp)
     int *flagp;
{
  if ((*flagp & RPCCLNT_SNDLOCK) == 0)
    panic("rpc sndunlock");
  *flagp &= ~RPCCLNT_SNDLOCK;
  if (*flagp & RPCCLNT_WANTSND)
    {
      *flagp &= ~RPCCLNT_WANTSND;
    }
}

static int rpcclnt_rcvlock(task)
     struct rpctask *task;
{
  int *flagp = &task->r_rpcclnt->rc_flag;
  int slpflag, slptimeo = 0;

  if (*flagp & RPCCLNT_INT)
    slpflag = PCATCH;
  else
    slpflag = 0;

  while (*flagp & RPCCLNT_RCVLOCK)
    {
      if (rpcclnt_sigintr(task->r_rpcclnt, task, task->r_td))
        return (EINTR);
      *flagp |= RPCCLNT_WANTRCV;
      tsleep((caddr_t) flagp, slpflag | (PZERO - 1), "rpcrcvlk", slptimeo);
      if (slpflag == PCATCH)
        {
          slpflag = 0;
          slptimeo = 2 * CLOCKS_PER_SEC;
        }
    }
  *flagp |= RPCCLNT_RCVLOCK;
  return (0);
}

/*
 * Unlock the stream socket for others.
 */
static void rpcclnt_rcvunlock(flagp)
     int *flagp;
{

  if ((*flagp & RPCCLNT_RCVLOCK) == 0)
    panic("nfs rcvunlock");
  *flagp &= ~RPCCLNT_RCVLOCK;
  if (*flagp & RPCCLNT_WANTRCV)
    {
      *flagp &= ~RPCCLNT_WANTRCV;
      wakeup((caddr_t) flagp);
    }
}
#endif

/*
 * Build the RPC header and fill in the authorization info.
 */
int rpcclnt_buildheader(struct rpcclnt *rc, int procid,
                        int xidp, struct rpc_call *call)
{
  struct timeval *tv;
  srand(time(NULL));

  /* 
   * The RPC header.
   */

  /* Get a new (non-zero) xid */
  if ((rpcclnt_xid == 0) && (rpcclnt_xid_touched == 0))
    {
      rpcclnt_xid = rand();
      rpcclnt_xid_touched = 1;
    }
  else
    {
      do
        {
          xidp = rand();
        }
      while ((xidp % 256) == 0);
      rpcclnt_xid += xidp;
    }

  call->rp_xid = xidp = txdr_unsigned(rpcclnt_xid);
  call->rp_direction = rpc_call;
  call->rp_rpcvers = rpc_vers;
  call->rp_prog = txdr_unsigned(rc->rc_prog->prog_id);
  call->rp_vers = txdr_unsigned(rc->rc_prog->prog_version);
  call->rp_proc = txdr_unsigned(procid);

  /* rpc_auth part (auth_unix as root) */

  call->rpc_auth.authtype = rpc_auth_null;
  call->rpc_auth.authlen = txdr_unsigned(sizeof(NULL));

  tv->tv_sec = 1;
#ifdef CONFIG_NFS_UNIX_AUTH
  call->rpc_unix.ua_time = txdr_unsigned(tv->tv_sec);
  call->rpc_unix.ua_hostname = 0;
  call->rpc_unix.ua_uid = geteuid();
  call->rpc_unix.ua_gid = getegid();
  call->rpc_unix.ua_gidlist = 0;
#endif
  /* rpc_verf part (auth_null) */

  call->rpc_verf.authtype = 0;
  call->rpc_verf.authlen = 0;

  return (0);
}

static uint32_t rpcclnt_proct(struct rpcclnt *rpc, uint32_t procid)
{
  if (rpc->rc_proctlen != 0 && rpc->rc_proct != NULL &&
      procid < rpc->rc_proctlen)
    return (rpc->rc_proct[procid]);

  return (0);
}

int rpcclnt_cancelreqs(struct rpcclnt *rpc)
{
  struct rpctask *task;
  int i;

  for (task = (struct rpctask *)rpctask_q->head; task;
       task = (struct rpctask *)task->r_chain.flink)
    {
      if (rpc != task->r_rpcclnt || (task->r_flags & TASK_SOFTTERM))
        continue;
      rpcclnt_softterm(task);
    }

  for (i = 0; i < 30; i++)
    {
      for (task = (struct rpctask *)rpctask_q->head; task;
           task = (struct rpctask *)task->r_chain.flink)
        {
          if (rpc == task->r_rpcclnt)
            break;
        }
      if (task == NULL)
        return (0);
    }

  return (EBUSY);
}

static void rpcclnt_softterm(struct rpctask *task)
{
  task->r_flags |= TASK_SOFTTERM;
  if (task->r_flags & TASK_SENT)
    {
      task->r_rpcclnt->rc_sent -= RPC_CWNDSCALE;
      task->r_flags &= ~TASK_SENT;
    }
}