/*	$OpenBSD: rpc_prot.c,v 1.12 2015/01/16 16:48:51 deraadt Exp $ */

/*
 * 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.
 */

/*
 * rpc_prot.c
 *
 * This set of routines implements the rpc message definition,
 * its serializer and some common rpc utility routines.
 * The routines are meant for various implementations of rpc -
 * they are NOT for the rpc client or rpc service implementations!
 * Because authentication stuff is easy and is part of rpc, the opaque
 * routines are also in this program.
 */

#include <rpc/rpc.h>

/* * * * * * * * * * * * * * XDR Authentication * * * * * * * * * * * */

struct opaque_auth _null_auth;

/*
 * XDR an opaque authentication struct
 * (see auth.h)
 */
bool_t
xdr_opaque_auth(XDR *xdrs, struct opaque_auth *ap)
{

	if (xdr_enum(xdrs, &(ap->oa_flavor)))
		return (xdr_bytes(xdrs, &ap->oa_base,
		    &ap->oa_length, MAX_AUTH_BYTES));
	return (FALSE);
}

/*
 * XDR a DES block
 */
bool_t
xdr_des_block(XDR *xdrs, des_block *blkp)
{
	return (xdr_opaque(xdrs, (caddr_t)blkp, sizeof(des_block)));
}

/* * * * * * * * * * * * * * XDR RPC MESSAGE * * * * * * * * * * * * * * * */

/*
 * XDR the MSG_ACCEPTED part of a reply message union
 */
bool_t 
xdr_accepted_reply(XDR *xdrs, struct accepted_reply *ar)
{

	/* personalized union, rather than calling xdr_union */
	if (! xdr_opaque_auth(xdrs, &(ar->ar_verf)))
		return (FALSE);
	if (! xdr_enum(xdrs, (enum_t *)&(ar->ar_stat)))
		return (FALSE);

	switch (ar->ar_stat) {
	case SUCCESS:
		return ((*(ar->ar_results.proc))(xdrs, ar->ar_results.where));
	case PROG_MISMATCH:
		if (!xdr_u_int32_t(xdrs, &(ar->ar_vers.low)))
			return (FALSE);
		return (xdr_u_int32_t(xdrs, &(ar->ar_vers.high)));
	default:
		return (TRUE);  /* TRUE => open ended set of problems */
	}
}

/*
 * XDR the MSG_DENIED part of a reply message union
 */
bool_t 
xdr_rejected_reply(XDR *xdrs, struct rejected_reply *rr)
{

	/* personalized union, rather than calling xdr_union */
	if (! xdr_enum(xdrs, (enum_t *)&(rr->rj_stat)))
		return (FALSE);

	switch (rr->rj_stat) {
	case RPC_MISMATCH:
		if (!xdr_u_int32_t(xdrs, &(rr->rj_vers.low)))
			return (FALSE);
		return (xdr_u_int32_t(xdrs, &(rr->rj_vers.high)));
	case AUTH_ERROR:
		return (xdr_enum(xdrs, (enum_t *)&(rr->rj_why)));
	}
	return (FALSE);
}

static struct xdr_discrim reply_dscrm[3] = {
	{ (int)MSG_ACCEPTED, xdr_accepted_reply },
	{ (int)MSG_DENIED, xdr_rejected_reply },
	{ __dontcare__, NULL } };

/*
 * XDR a reply message
 */
bool_t
xdr_replymsg(XDR *xdrs, struct rpc_msg *rmsg)
{
	if (xdr_u_int32_t(xdrs, &(rmsg->rm_xid)) && 
	    xdr_enum(xdrs, (enum_t *)&(rmsg->rm_direction)) &&
	    rmsg->rm_direction == REPLY)
		return (xdr_union(xdrs, (enum_t *)&(rmsg->rm_reply.rp_stat),
		   (caddr_t)&(rmsg->rm_reply.ru), reply_dscrm, NULL));
	return (FALSE);
}


/*
 * Serializes the "static part" of a call message header.
 * The fields include: rm_xid, rm_direction, rpcvers, prog, and vers.
 * The rm_xid is not really static, but the user can easily munge on the fly.
 */
bool_t
xdr_callhdr(XDR *xdrs, struct rpc_msg *cmsg)
{

	cmsg->rm_direction = CALL;
	cmsg->rm_call.cb_rpcvers = RPC_MSG_VERSION;
	if (xdrs->x_op == XDR_ENCODE &&
	    xdr_u_int32_t(xdrs, &(cmsg->rm_xid)) &&
	    xdr_enum(xdrs, (enum_t *)&(cmsg->rm_direction)) &&
	    xdr_u_int32_t(xdrs, &(cmsg->rm_call.cb_rpcvers)) &&
	    xdr_u_int32_t(xdrs, &(cmsg->rm_call.cb_prog)))
		return (xdr_u_int32_t(xdrs, &(cmsg->rm_call.cb_vers)));
	return (FALSE);
}

/* ************************** Client utility routine ************* */

static void
accepted(enum accept_stat acpt_stat, struct rpc_err *error)
{

	switch (acpt_stat) {

	case PROG_UNAVAIL:
		error->re_status = RPC_PROGUNAVAIL;
		return;

	case PROG_MISMATCH:
		error->re_status = RPC_PROGVERSMISMATCH;
		return;

	case PROC_UNAVAIL:
		error->re_status = RPC_PROCUNAVAIL;
		return;

	case GARBAGE_ARGS:
		error->re_status = RPC_CANTDECODEARGS;
		return;

	case SYSTEM_ERR:
		error->re_status = RPC_SYSTEMERROR;
		return;

	case SUCCESS:
		error->re_status = RPC_SUCCESS;
		return;
	}
	/* something's wrong, but we don't know what ... */
	error->re_status = RPC_FAILED;
	error->re_lb.s1 = (long)MSG_ACCEPTED;
	error->re_lb.s2 = (long)acpt_stat;
}

static void 
rejected(enum reject_stat rjct_stat, struct rpc_err *error)
{

	switch (rjct_stat) {

	case RPC_MISMATCH:
		error->re_status = RPC_VERSMISMATCH;
		return;

	case AUTH_ERROR:
		error->re_status = RPC_AUTHERROR;
		return;
	}
	/* something's wrong, but we don't know what ... */
	error->re_status = RPC_FAILED;
	error->re_lb.s1 = (long)MSG_DENIED;
	error->re_lb.s2 = (long)rjct_stat;
}

/*
 * given a reply message, fills in the error
 */
void
_seterr_reply(struct rpc_msg *msg, struct rpc_err *error)
{

	/* optimized for normal, SUCCESSful case */
	switch (msg->rm_reply.rp_stat) {

	case MSG_ACCEPTED:
		if (msg->acpted_rply.ar_stat == SUCCESS) {
			error->re_status = RPC_SUCCESS;
			return;
		};
		accepted(msg->acpted_rply.ar_stat, error);
		break;

	case MSG_DENIED:
		rejected(msg->rjcted_rply.rj_stat, error);
		break;

	default:
		error->re_status = RPC_FAILED;
		error->re_lb.s1 = (long)(msg->rm_reply.rp_stat);
		break;
	}
	switch (error->re_status) {

	case RPC_VERSMISMATCH:
		error->re_vers.low = msg->rjcted_rply.rj_vers.low;
		error->re_vers.high = msg->rjcted_rply.rj_vers.high;
		break;

	case RPC_AUTHERROR:
		error->re_why = msg->rjcted_rply.rj_why;
		break;

	case RPC_PROGVERSMISMATCH:
		error->re_vers.low = msg->acpted_rply.ar_vers.low;
		error->re_vers.high = msg->acpted_rply.ar_vers.high;
		break;
	}
}