/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2020 Tintri by DDN, Inc. All rights reserved.
 */

/*
 * Server-side NDR stream (PDU) operations. Stream operations should
 * return TRUE (non-zero) on success or FALSE (zero or a null pointer)
 * on failure. When an operation returns FALSE, including ndo_malloc()
 * returning NULL, it should set the nds->error to indicate what went
 * wrong.
 *
 * When available, the relevant ndr reference is passed to the
 * operation but keep in mind that it may be a null pointer.
 *
 * Functions ndo_get_pdu(), ndo_put_pdu(), and ndo_pad_pdu()
 * must never grow the PDU data. A request for out-of-bounds data is
 * an error. The swap_bytes flag is 1 if NDR knows that the byte-
 * order in the PDU is different from the local system.
 */

#include <sys/types.h>
#include <stdarg.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include <assert.h>

#include <libmlrpc.h>

#define NDOBUFSZ                128

#define NDR_PDU_BLOCK_SIZE      (4*1024)
#define NDR_PDU_BLOCK_MASK      (NDR_PDU_BLOCK_SIZE - 1)
#define NDR_PDU_ALIGN(N) \
        (((N) + NDR_PDU_BLOCK_SIZE) & ~NDR_PDU_BLOCK_MASK)
#define NDR_PDU_MAX_SIZE                (64*1024*1024)

static char *ndo_malloc(ndr_stream_t *, unsigned, ndr_ref_t *);
static int ndo_free(ndr_stream_t *, char *, ndr_ref_t *);
static int ndo_grow_pdu(ndr_stream_t *, unsigned long, ndr_ref_t *);
static int ndo_pad_pdu(ndr_stream_t *, unsigned long, unsigned long,
    ndr_ref_t *);
static int ndo_get_pdu(ndr_stream_t *, unsigned long, unsigned long,
    char *, int, ndr_ref_t *);
static int ndo_put_pdu(ndr_stream_t *, unsigned long, unsigned long,
    char *, int, ndr_ref_t *);
static void ndo_tattle(ndr_stream_t *, char *, ndr_ref_t *);
static void ndo_tattle_error(ndr_stream_t *, ndr_ref_t *);
static int ndo_reset(ndr_stream_t *);
static void ndo_destruct(ndr_stream_t *);
static void ndo_hexfmt(uint8_t *, int, int, char *, int);

/*
 * The ndr stream operations table.
 */
static ndr_stream_ops_t nds_ops = {
    ndo_malloc,
    ndo_free,
    ndo_grow_pdu,
    ndo_pad_pdu,
    ndo_get_pdu,
    ndo_put_pdu,
    ndo_tattle,
    ndo_tattle_error,
    ndo_reset,
    ndo_destruct
};

/*
 * nds_bswap
 *
 * Copies len bytes from src to dst such that dst contains the bytes
 * from src in reverse order.
 *
 * We expect to be dealing with bytes, words, dwords etc. So the
 * length must be non-zero and a power of 2.
 */
void
nds_bswap(void *srcbuf, void *dstbuf, size_t len)
{
        uint8_t *src = (uint8_t *)srcbuf;
        uint8_t *dst = (uint8_t *)dstbuf;

        if ((len != 0) && ((len & (len - 1)) == 0)) {
                src += len;

                while (len--)
                        *dst++ = *(--src);
        }
}

/*
 * nds_initialize
 *
 * Initialize a stream. Sets up the PDU parameters and assigns the stream
 * operations and the reference to the heap. An external heap is provided
 * to the stream, rather than each stream creating its own heap.
 */
int
nds_initialize(ndr_stream_t *nds, unsigned pdu_size_hint,
    int composite_op, ndr_heap_t *heap)
{
        unsigned size;

        assert(nds);
        assert(heap);

        bzero(nds, sizeof (*nds));
        nds->ndo = &nds_ops;
        nds->heap = (struct ndr_heap *)heap;

        if (pdu_size_hint > NDR_PDU_MAX_SIZE) {
                nds->error = NDR_ERR_BOUNDS_CHECK;
                nds->error_ref = __LINE__;
                NDS_TATTLE_ERROR(nds, NULL, NULL);
                return (NDR_DRC_FAULT_RESOURCE_1);
        }

        size = (pdu_size_hint == 0) ? NDR_PDU_BLOCK_SIZE : pdu_size_hint;

        if ((nds->pdu_base_addr = malloc(size)) == NULL) {
                nds->error = NDR_ERR_MALLOC_FAILED;
                nds->error_ref = __LINE__;
                NDS_TATTLE_ERROR(nds, NULL, NULL);
                return (NDR_DRC_FAULT_OUT_OF_MEMORY);
        }

        nds->pdu_max_size = size;
        nds->pdu_size = 0;
        nds->pdu_base_offset = (unsigned long)nds->pdu_base_addr;

        nds->m_op = NDR_MODE_TO_M_OP(composite_op);
        nds->dir  = NDR_MODE_TO_DIR(composite_op);

        nds->outer_queue_tailp = &nds->outer_queue_head;
        return (0);
}

/*
 * nds_destruct
 *
 * Destroy a stream. This is an external interface to provide access to
 * the stream's destruct operation.
 */
void
nds_destruct(ndr_stream_t *nds)
{
        if ((nds == NULL) || (nds->ndo == NULL))
                return;

        NDS_DESTRUCT(nds);
}

/*
 * Print NDR stream state.
 */
void
nds_show_state(ndr_stream_t *nds)
{
        if (nds == NULL) {
                ndo_printf(NULL, NULL, "nds: <null");
                return;
        }

        ndo_printf(NULL, NULL, "nds: base=0x%x, size=%d, max=%d, scan=%d, "
            "hdr_size=%d, body_size=%d, body_offset=%d",
            nds->pdu_base_offset, nds->pdu_size, nds->pdu_max_size,
            nds->pdu_scan_offset, nds->pdu_hdr_size, nds->pdu_body_size,
            nds->pdu_body_offset);
}

/*
 * ndo_malloc
 *
 * Allocate memory from the stream heap.
 */
/*ARGSUSED*/
static char *
ndo_malloc(ndr_stream_t *nds, unsigned len, ndr_ref_t *ref)
{
        return (ndr_heap_malloc((ndr_heap_t *)nds->heap, len));
}

/*
 * ndo_free
 *
 * Always succeeds: cannot free individual stream allocations.
 */
/*ARGSUSED*/
static int
ndo_free(ndr_stream_t *nds, char *p, ndr_ref_t *ref)
{
        return (1);
}

/*
 * ndo_grow_pdu
 *
 * This is the only place that should change the size of the PDU. If the
 * desired offset is beyond the current PDU size, we realloc the PDU
 * buffer to accommodate the request. For efficiency, the PDU is always
 * extended to a NDR_PDU_BLOCK_SIZE boundary. Requests to grow the PDU
 * beyond NDR_PDU_MAX_SIZE are rejected.
 *
 * Returns 1 to indicate success. Otherwise 0 to indicate failure.
 */
static int
ndo_grow_pdu(ndr_stream_t *nds, unsigned long want_end_offset, ndr_ref_t *ref)
{
        unsigned char *pdu_addr;
        unsigned pdu_max_size;

        ndo_printf(nds, ref, "grow %d", want_end_offset);

        pdu_max_size = nds->pdu_max_size;

        if (want_end_offset > pdu_max_size) {
                pdu_max_size = NDR_PDU_ALIGN(want_end_offset);

                if (pdu_max_size >= NDR_PDU_MAX_SIZE)
                        return (0);

                pdu_addr = realloc(nds->pdu_base_addr, pdu_max_size);
                if (pdu_addr == 0)
                        return (0);

                nds->pdu_max_size = pdu_max_size;
                nds->pdu_base_addr = pdu_addr;
                nds->pdu_base_offset = (unsigned long)pdu_addr;
        }

        nds->pdu_size = want_end_offset;
        return (1);
}

static int
ndo_pad_pdu(ndr_stream_t *nds, unsigned long pdu_offset,
    unsigned long n_bytes, ndr_ref_t *ref)
{
        unsigned char *data;

        data = (unsigned char *)nds->pdu_base_offset;
        data += pdu_offset;

        ndo_printf(nds, ref, "pad %d@%-3d", n_bytes, pdu_offset);

        bzero(data, n_bytes);
        return (1);
}

/*
 * ndo_get_pdu
 *
 * The swap flag is 1 if NDR knows that the byte-order in the PDU
 * is different from the local system.
 *
 * Returns 1 on success or 0 to indicate failure.
 */
static int
ndo_get_pdu(ndr_stream_t *nds, unsigned long pdu_offset,
    unsigned long n_bytes, char *buf, int swap_bytes, ndr_ref_t *ref)
{
        unsigned char *data;
        char hexbuf[NDOBUFSZ];

        data = (unsigned char *)nds->pdu_base_offset;
        data += pdu_offset;

        ndo_hexfmt(data, n_bytes, swap_bytes, hexbuf, NDOBUFSZ);

        ndo_printf(nds, ref, "get %d@%-3d = %s",
            n_bytes, pdu_offset, hexbuf);

        if (!swap_bytes)
                bcopy(data, buf, n_bytes);
        else
                nds_bswap(data, (unsigned char *)buf, n_bytes);

        return (1);
}

/*
 * ndo_put_pdu
 *
 * This is a receiver makes right protocol. So we do not need
 * to be concerned about the byte-order of an outgoing PDU.
 */
/*ARGSUSED*/
static int
ndo_put_pdu(ndr_stream_t *nds, unsigned long pdu_offset,
    unsigned long n_bytes, char *buf, int swap_bytes, ndr_ref_t *ref)
{
        unsigned char *data;
        char hexbuf[NDOBUFSZ];

        data = (unsigned char *)nds->pdu_base_offset;
        data += pdu_offset;

        ndo_hexfmt((uint8_t *)buf, n_bytes, 0, hexbuf, NDOBUFSZ);

        ndo_printf(nds, ref, "put %d@%-3d = %s",
            n_bytes, pdu_offset, hexbuf);

        bcopy(buf, data, n_bytes);
        return (1);
}

static void
ndo_tattle(ndr_stream_t *nds, char *what, ndr_ref_t *ref)
{
        ndo_printf(nds, ref, what);
}

static void
ndo_tattle_error(ndr_stream_t *nds, ndr_ref_t *ref)
{
        unsigned char *data;
        char hexbuf[NDOBUFSZ];

        if (nds->pdu_base_addr != NULL) {
                data = (unsigned char *)nds->pdu_base_offset;
                if (ref)
                        data += ref->pdu_offset;
                else
                        data += nds->pdu_scan_offset;

                ndo_hexfmt(data, 16, 0, hexbuf, NDOBUFSZ);
        } else {
                bzero(hexbuf, NDOBUFSZ);
        }

        ndo_printf(nds, ref, "ERROR=%d REF=%d OFFSET=%d SIZE=%d/%d",
            nds->error, nds->error_ref, nds->pdu_scan_offset,
            nds->pdu_size, nds->pdu_max_size);
        ndo_printf(nds, ref, "      %s", hexbuf);
}

/*
 * ndo_reset
 *
 * Reset a stream: zap the outer_queue. We don't need to tamper
 * with the stream heap: it's handled externally to the stream.
 */
static int
ndo_reset(ndr_stream_t *nds)
{
        ndo_printf(nds, 0, "reset");

        nds->pdu_size = 0;
        nds->pdu_scan_offset = 0;
        nds->outer_queue_head = 0;
        nds->outer_current = 0;
        nds->outer_queue_tailp = &nds->outer_queue_head;

        return (1);
}

/*
 * ndo_destruct
 *
 * Destruct a stream: zap the outer_queue.
 * Note: heap management (creation/destruction) is external to the stream.
 */
static void
ndo_destruct(ndr_stream_t *nds)
{

        ndo_printf(nds, 0, "destruct");

        if (nds == NULL)
                return;

        if (nds->pdu_base_addr != NULL) {
                free(nds->pdu_base_addr);
                nds->pdu_base_addr = NULL;
                nds->pdu_base_offset = 0;
        }

        nds->outer_queue_head = 0;
        nds->outer_current = 0;
        nds->outer_queue_tailp = &nds->outer_queue_head;
}

/*
 * Printf style formatting for NDR operations.
 */
void
ndo_printf(ndr_stream_t *nds, ndr_ref_t *ref, const char *fmt, ...)
{
        va_list ap;
        char buf[NDOBUFSZ];

        va_start(ap, fmt);
        (void) vsnprintf(buf, NDOBUFSZ, fmt, ap);
        va_end(ap);

        if (nds)
                ndo_fmt(nds, ref, buf);
        else
                ndo_trace(buf);
}

/*
 * Main output formatter for NDR operations.
 *
 *      UI 03 ... rpc_vers           get 1@0   =    5 {05}
 *      UI 03 ... rpc_vers_minor     get 1@1   =    0 {00}
 *
 *      U       Marshalling flag (M=marshal, U=unmarshal)
 *      I       Direction flag (I=in, O=out)
 *      ...     Field name
 *      get     PDU operation (get or put)
 *      1@0     Bytes @ offset (i.e. 1 byte at offset 0)
 *      {05}    Value
 */
void
ndo_fmt(ndr_stream_t *nds, ndr_ref_t *ref, char *note)
{
        ndr_ref_t       *p;
        int             indent;
        char            ref_name[NDOBUFSZ];
        char            buf[NDOBUFSZ];
        int             m_op_c = '?', dir_c = '?';

        switch (nds->m_op) {
        case 0:                         m_op_c = '-';   break;
        case NDR_M_OP_MARSHALL:         m_op_c = 'M';   break;
        case NDR_M_OP_UNMARSHALL:       m_op_c = 'U';   break;
        default:                        m_op_c = '?';   break;
        }

        switch (nds->dir) {
        case 0:                         dir_c = '-';    break;
        case NDR_DIR_IN:                dir_c = 'I';    break;
        case NDR_DIR_OUT:               dir_c = 'O';    break;
        default:                        dir_c = '?';    break;
        }

        for (indent = 0, p = ref; p; p = p->enclosing)
                indent++;

        if (ref && ref->name) {
                if (*ref->name == '[' && ref->enclosing) {
                        indent--;
                        (void) snprintf(ref_name, NDOBUFSZ, "%s%s",
                            ref->enclosing->name, ref->name);
                } else {
                        (void) strlcpy(ref_name, ref->name, NDOBUFSZ);
                }
        } else {
                (void) strlcpy(ref_name, "----", NDOBUFSZ);
        }

        (void) snprintf(buf, NDOBUFSZ, "%c%c %-.*s %-*s  %s",
            m_op_c, dir_c, indent,
            "....+....+....+....+....+....",
            20 - indent, ref_name, note);

        ndo_trace(buf);
}

/*ARGSUSED*/
void
ndo_trace(const char *s)
{
        /*
         * Temporary fbt for dtrace until user space sdt enabled.
         */
}

/*
 * Format data as hex bytes (limit is 10 bytes):
 *
 *      1188689424 {10 f6 d9 46}
 *
 * If the input data is greater than 10 bytes, an ellipsis will
 * be inserted before the closing brace.
 */
static void
ndo_hexfmt(uint8_t *data, int size, int swap_bytes, char *buf, int len)
{
        char *p = buf;
        int interp = 1;
        uint32_t c;
        int n;
        int i;

        n = (size > 10) ? 10 : size;
        if (n > len-1)
                n = len-1;

        switch (size) {
        case 1:
                c = *(uint8_t *)data;
                break;
        case 2:
                if (swap_bytes == 0) /*LINTED E_BAD_PTR_CAST_ALIGN*/
                        c = *(uint16_t *)data;
                else
                        c = (data[0] << 8) | data[1];
                break;
        case 4:
                if (swap_bytes == 0) { /*LINTED E_BAD_PTR_CAST_ALIGN*/
                        c = *(uint32_t *)data;
                } else {
                        c = (data[0] << 24) | (data[1] << 16)
                            | (data[2] << 8) | data[3];
                }
                break;
        default:
                c = 0;
                interp = 0;
                break;
        }

        if (interp)
                p += sprintf(p, "%4u {", c);
        else
                p += sprintf(p, " {");

        p += sprintf(p, "%02x", data[0]);
        for (i = 1; i < n; i++)
                p += sprintf(p, " %02x", data[i]);
        if (size > 10)
                p += sprintf(p, " ...}");
        else
                p += sprintf(p, "}");

        /*
         * Show c if it's a printable character or wide-char.
         */
        if (size < 4 && isprint((uint8_t)c))
                (void) sprintf(p, " %c", (uint8_t)c);
}