/*
 * clnt_tcp.c, Implements a TCP/IP based, client side RPC.
 *
 * Copyright (c) 2010, Oracle America, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of the "Oracle America, Inc." 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 COPYRIGHT HOLDERS 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
 *   COPYRIGHT HOLDER 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.
 *
 * TCP based RPC supports 'batched calls'.
 * A sequence of calls may be batched-up in a send buffer.  The rpc call
 * return immediately to the client even though the call was not necessarily
 * sent.  The batching occurs if the results' xdr routine is NULL (0) AND
 * the rpc timeout value is zero (see clnt.h, rpc).
 *
 * Clients should NOT casually batch calls that in fact return results; that is,
 * the server side should be aware that a call is batched and not produce any
 * return message.  Batched calls that produce many result messages can
 * deadlock (netlock) the client and the server....
 *
 * Now go hang yourself.
 */

#include <netdb.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <libintl.h>
#include <rpc/rpc.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <rpc/pmap_clnt.h>
#ifdef USE_IN_LIBIO
# include <wchar.h>
#endif

extern u_long _create_xid (void);

#define MCALL_MSG_SIZE 24

struct ct_data
  {
    int ct_sock;
    bool_t ct_closeit;
    struct timeval ct_wait;
    bool_t ct_waitset;		/* wait set by clnt_control? */
    struct sockaddr_in ct_addr;
    struct rpc_err ct_error;
    char ct_mcall[MCALL_MSG_SIZE];	/* marshalled callmsg */
    u_int ct_mpos;		/* pos after marshal */
    XDR ct_xdrs;
  };

static int readtcp (char *, char *, int);
static int writetcp (char *, char *, int);

static enum clnt_stat clnttcp_call (CLIENT *, u_long, xdrproc_t, caddr_t,
				    xdrproc_t, caddr_t, struct timeval);
static void clnttcp_abort (void);
static void clnttcp_geterr (CLIENT *, struct rpc_err *);
static bool_t clnttcp_freeres (CLIENT *, xdrproc_t, caddr_t);
static bool_t clnttcp_control (CLIENT *, int, char *);
static void clnttcp_destroy (CLIENT *);

static const struct clnt_ops tcp_ops =
{
  clnttcp_call,
  clnttcp_abort,
  clnttcp_geterr,
  clnttcp_freeres,
  clnttcp_destroy,
  clnttcp_control
};

/*
 * Create a client handle for a tcp/ip connection.
 * If *sockp<0, *sockp is set to a newly created TCP socket and it is
 * connected to raddr.  If *sockp non-negative then
 * raddr is ignored.  The rpc/tcp package does buffering
 * similar to stdio, so the client must pick send and receive buffer sizes,];
 * 0 => use the default.
 * If raddr->sin_port is 0, then a binder on the remote machine is
 * consulted for the right port number.
 * NB: *sockp is copied into a private area.
 * NB: It is the clients responsibility to close *sockp.
 * NB: The rpch->cl_auth is set null authentication.  Caller may wish to set this
 * something more useful.
 */
CLIENT *
clnttcp_create (struct sockaddr_in *raddr, u_long prog, u_long vers,
		int *sockp, u_int sendsz, u_int recvsz)
{
  CLIENT *h;
  struct ct_data *ct;
  struct rpc_msg call_msg;

  h = (CLIENT *) mem_alloc (sizeof (*h));
  ct = (struct ct_data *) mem_alloc (sizeof (*ct));
  if (h == NULL || ct == NULL)
    {
      struct rpc_createerr *ce = &get_rpc_createerr ();
      (void) __fxprintf (NULL, "%s: %s", __func__, _("out of memory\n"));
      ce->cf_stat = RPC_SYSTEMERROR;
      ce->cf_error.re_errno = ENOMEM;
      goto fooy;
    }

  /*
   * If no port number given ask the pmap for one
   */
  if (raddr->sin_port == 0)
    {
      u_short port;
      if ((port = pmap_getport (raddr, prog, vers, IPPROTO_TCP)) == 0)
	{
	  mem_free ((caddr_t) ct, sizeof (struct ct_data));
	  mem_free ((caddr_t) h, sizeof (CLIENT));
	  return ((CLIENT *) NULL);
	}
      raddr->sin_port = htons (port);
    }

  /*
   * If no socket given, open one
   */
  if (*sockp < 0)
    {
      *sockp = __socket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
      (void) bindresvport (*sockp, (struct sockaddr_in *) 0);
      if ((*sockp < 0)
	  || (__connect (*sockp, (struct sockaddr *) raddr,
			 sizeof (*raddr)) < 0))
	{
	  struct rpc_createerr *ce = &get_rpc_createerr ();
	  ce->cf_stat = RPC_SYSTEMERROR;
	  ce->cf_error.re_errno = errno;
	  if (*sockp >= 0)
	    (void) __close (*sockp);
	  goto fooy;
	}
      ct->ct_closeit = TRUE;
    }
  else
    {
      ct->ct_closeit = FALSE;
    }

  /*
   * Set up private data struct
   */
  ct->ct_sock = *sockp;
  ct->ct_wait.tv_usec = 0;
  ct->ct_waitset = FALSE;
  ct->ct_addr = *raddr;

  /*
   * Initialize call message
   */
  call_msg.rm_xid = _create_xid ();
  call_msg.rm_direction = CALL;
  call_msg.rm_call.cb_rpcvers = RPC_MSG_VERSION;
  call_msg.rm_call.cb_prog = prog;
  call_msg.rm_call.cb_vers = vers;

  /*
   * pre-serialize the static part of the call msg and stash it away
   */
  INTUSE(xdrmem_create) (&(ct->ct_xdrs), ct->ct_mcall, MCALL_MSG_SIZE,
			 XDR_ENCODE);
  if (!INTUSE(xdr_callhdr) (&(ct->ct_xdrs), &call_msg))
    {
      if (ct->ct_closeit)
	{
	  (void) __close (*sockp);
	}
      goto fooy;
    }
  ct->ct_mpos = XDR_GETPOS (&(ct->ct_xdrs));
  XDR_DESTROY (&(ct->ct_xdrs));

  /*
   * Create a client handle which uses xdrrec for serialization
   * and authnone for authentication.
   */
  INTUSE(xdrrec_create) (&(ct->ct_xdrs), sendsz, recvsz,
			 (caddr_t) ct, readtcp, writetcp);
  h->cl_ops = (struct clnt_ops *) &tcp_ops;
  h->cl_private = (caddr_t) ct;
  h->cl_auth = INTUSE(authnone_create) ();
  return h;

fooy:
  /*
   * Something goofed, free stuff and barf
   */
  mem_free ((caddr_t) ct, sizeof (struct ct_data));
  mem_free ((caddr_t) h, sizeof (CLIENT));
  return ((CLIENT *) NULL);
}
INTDEF (clnttcp_create)

static enum clnt_stat
clnttcp_call (h, proc, xdr_args, args_ptr, xdr_results, results_ptr, timeout)
     CLIENT *h;
     u_long proc;
     xdrproc_t xdr_args;
     caddr_t args_ptr;
     xdrproc_t xdr_results;
     caddr_t results_ptr;
     struct timeval timeout;
{
  struct ct_data *ct = (struct ct_data *) h->cl_private;
  XDR *xdrs = &(ct->ct_xdrs);
  struct rpc_msg reply_msg;
  u_long x_id;
  u_int32_t *msg_x_id = (u_int32_t *) (ct->ct_mcall);	/* yuk */
  bool_t shipnow;
  int refreshes = 2;

  if (!ct->ct_waitset)
    {
      ct->ct_wait = timeout;
    }

  shipnow =
    (xdr_results == (xdrproc_t) 0 && ct->ct_wait.tv_sec == 0
     && ct->ct_wait.tv_usec == 0) ? FALSE : TRUE;

call_again:
  xdrs->x_op = XDR_ENCODE;
  ct->ct_error.re_status = RPC_SUCCESS;
  x_id = ntohl (--(*msg_x_id));
  if ((!XDR_PUTBYTES (xdrs, ct->ct_mcall, ct->ct_mpos)) ||
      (!XDR_PUTLONG (xdrs, (long *) &proc)) ||
      (!AUTH_MARSHALL (h->cl_auth, xdrs)) ||
      (!(*xdr_args) (xdrs, args_ptr)))
    {
      if (ct->ct_error.re_status == RPC_SUCCESS)
	ct->ct_error.re_status = RPC_CANTENCODEARGS;
      (void) INTUSE(xdrrec_endofrecord) (xdrs, TRUE);
      return (ct->ct_error.re_status);
    }
  if (!INTUSE(xdrrec_endofrecord) (xdrs, shipnow))
    return ct->ct_error.re_status = RPC_CANTSEND;
  if (!shipnow)
    return RPC_SUCCESS;
  /*
   * Hack to provide rpc-based message passing
   */
  if (ct->ct_wait.tv_sec == 0 && ct->ct_wait.tv_usec == 0)
    {
      return ct->ct_error.re_status = RPC_TIMEDOUT;
    }


  /*
   * Keep receiving until we get a valid transaction id
   */
  xdrs->x_op = XDR_DECODE;
  while (TRUE)
    {
      reply_msg.acpted_rply.ar_verf = _null_auth;
      reply_msg.acpted_rply.ar_results.where = NULL;
      reply_msg.acpted_rply.ar_results.proc = (xdrproc_t)INTUSE(xdr_void);
      if (!INTUSE(xdrrec_skiprecord) (xdrs))
	return (ct->ct_error.re_status);
      /* now decode and validate the response header */
      if (!INTUSE(xdr_replymsg) (xdrs, &reply_msg))
	{
	  if (ct->ct_error.re_status == RPC_SUCCESS)
	    continue;
	  return ct->ct_error.re_status;
	}
      if ((u_int32_t) reply_msg.rm_xid == (u_int32_t) x_id)
	break;
    }

  /*
   * process header
   */
  _seterr_reply (&reply_msg, &(ct->ct_error));
  if (ct->ct_error.re_status == RPC_SUCCESS)
    {
      if (!AUTH_VALIDATE (h->cl_auth, &reply_msg.acpted_rply.ar_verf))
	{
	  ct->ct_error.re_status = RPC_AUTHERROR;
	  ct->ct_error.re_why = AUTH_INVALIDRESP;
	}
      else if (!(*xdr_results) (xdrs, results_ptr))
	{
	  if (ct->ct_error.re_status == RPC_SUCCESS)
	    ct->ct_error.re_status = RPC_CANTDECODERES;
	}
      /* free verifier ... */
      if (reply_msg.acpted_rply.ar_verf.oa_base != NULL)
	{
	  xdrs->x_op = XDR_FREE;
	  (void) INTUSE(xdr_opaque_auth) (xdrs,
					  &(reply_msg.acpted_rply.ar_verf));
	}
    }				/* end successful completion */
  else
    {
      /* maybe our credentials need to be refreshed ... */
      if (refreshes-- && AUTH_REFRESH (h->cl_auth))
	goto call_again;
    }				/* end of unsuccessful completion */
  return ct->ct_error.re_status;
}

static void
clnttcp_geterr (h, errp)
     CLIENT *h;
     struct rpc_err *errp;
{
  struct ct_data *ct =
  (struct ct_data *) h->cl_private;

  *errp = ct->ct_error;
}

static bool_t
clnttcp_freeres (cl, xdr_res, res_ptr)
     CLIENT *cl;
     xdrproc_t xdr_res;
     caddr_t res_ptr;
{
  struct ct_data *ct = (struct ct_data *) cl->cl_private;
  XDR *xdrs = &(ct->ct_xdrs);

  xdrs->x_op = XDR_FREE;
  return (*xdr_res) (xdrs, res_ptr);
}

static void
clnttcp_abort ()
{
}

static bool_t
clnttcp_control (CLIENT *cl, int request, char *info)
{
  struct ct_data *ct = (struct ct_data *) cl->cl_private;


  switch (request)
    {
    case CLSET_FD_CLOSE:
      ct->ct_closeit = TRUE;
      break;
    case CLSET_FD_NCLOSE:
      ct->ct_closeit = FALSE;
      break;
    case CLSET_TIMEOUT:
      ct->ct_wait = *(struct timeval *) info;
      ct->ct_waitset = TRUE;
      break;
    case CLGET_TIMEOUT:
      *(struct timeval *) info = ct->ct_wait;
      break;
    case CLGET_SERVER_ADDR:
      *(struct sockaddr_in *) info = ct->ct_addr;
      break;
    case CLGET_FD:
      *(int *)info = ct->ct_sock;
      break;
    case CLGET_XID:
      /*
       * use the knowledge that xid is the
       * first element in the call structure *.
       * This will get the xid of the PREVIOUS call
       */
      *(u_long *)info = ntohl (*(u_long *)ct->ct_mcall);
      break;
    case CLSET_XID:
      /* This will set the xid of the NEXT call */
      *(u_long *)ct->ct_mcall =  htonl (*(u_long *)info - 1);
      /* decrement by 1 as clnttcp_call() increments once */
      break;
    case CLGET_VERS:
      /*
       * This RELIES on the information that, in the call body,
       * the version number field is the fifth field from the
       * begining of the RPC header. MUST be changed if the
       * call_struct is changed
       */
      *(u_long *)info = ntohl (*(u_long *)(ct->ct_mcall +
					   4 * BYTES_PER_XDR_UNIT));
      break;
    case CLSET_VERS:
      *(u_long *)(ct->ct_mcall + 4 * BYTES_PER_XDR_UNIT)
	= htonl (*(u_long *)info);
      break;
    case CLGET_PROG:
      /*
       * This RELIES on the information that, in the call body,
       * the program number field is the  field from the
       * begining of the RPC header. MUST be changed if the
       * call_struct is changed
       */
      *(u_long *)info = ntohl(*(u_long *)(ct->ct_mcall +
					  3 * BYTES_PER_XDR_UNIT));
      break;
    case CLSET_PROG:
      *(u_long *)(ct->ct_mcall + 3 * BYTES_PER_XDR_UNIT)
	= htonl(*(u_long *)info);
      break;
    /* The following are only possible with TI-RPC */
    case CLGET_RETRY_TIMEOUT:
    case CLSET_RETRY_TIMEOUT:
    case CLGET_SVC_ADDR:
    case CLSET_SVC_ADDR:
    case CLSET_PUSH_TIMOD:
    case CLSET_POP_TIMOD:
    default:
      return FALSE;
    }
  return TRUE;
}


static void
clnttcp_destroy (CLIENT *h)
{
  struct ct_data *ct =
  (struct ct_data *) h->cl_private;

  if (ct->ct_closeit)
    {
      (void) __close (ct->ct_sock);
    }
  XDR_DESTROY (&(ct->ct_xdrs));
  mem_free ((caddr_t) ct, sizeof (struct ct_data));
  mem_free ((caddr_t) h, sizeof (CLIENT));
}

/*
 * Interface between xdr serializer and tcp connection.
 * Behaves like the system calls, read & write, but keeps some error state
 * around for the rpc level.
 */
static int
readtcp (char *ctptr, char *buf, int len)
{
  struct ct_data *ct = (struct ct_data *)ctptr;
  struct pollfd fd;
  int milliseconds = (ct->ct_wait.tv_sec * 1000) +
    (ct->ct_wait.tv_usec / 1000);

  if (len == 0)
    return 0;

  fd.fd = ct->ct_sock;
  fd.events = POLLIN;
  while (TRUE)
    {
      switch (__poll(&fd, 1, milliseconds))
	{
	case 0:
	  ct->ct_error.re_status = RPC_TIMEDOUT;
	  return -1;

	case -1:
	  if (errno == EINTR)
	    continue;
	  ct->ct_error.re_status = RPC_CANTRECV;
	  ct->ct_error.re_errno = errno;
	  return -1;
	}
      break;
    }
  switch (len = __read (ct->ct_sock, buf, len))
    {

    case 0:
      /* premature eof */
      ct->ct_error.re_errno = ECONNRESET;
      ct->ct_error.re_status = RPC_CANTRECV;
      len = -1;			/* it's really an error */
      break;

    case -1:
      ct->ct_error.re_errno = errno;
      ct->ct_error.re_status = RPC_CANTRECV;
      break;
    }
  return len;
}

static int
writetcp (char *ctptr, char *buf, int len)
{
  int i, cnt;
  struct ct_data *ct = (struct ct_data*)ctptr;

  for (cnt = len; cnt > 0; cnt -= i, buf += i)
    {
      if ((i = __write (ct->ct_sock, buf, cnt)) == -1)
	{
	  ct->ct_error.re_errno = errno;
	  ct->ct_error.re_status = RPC_CANTSEND;
	  return -1;
	}
    }
  return len;
}