/*-
 * sar.c
 *
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2004 Maksim Yevmenkin <m_evmenkin@yahoo.com>
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 * $Id: sar.c,v 1.2 2004/01/08 23:46:51 max Exp $
 */

#include <sys/param.h>
#include <sys/queue.h>
#include <sys/uio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <assert.h>
#define L2CAP_SOCKET_CHECKED
#include <bluetooth.h>
#include <errno.h>
#include <sdp.h>
#include <stdio.h> /* for NULL */
#include "profile.h"
#include "provider.h"
#include "server.h"

/*
 * Prepare SDP attr/value pair. Check if profile implements the attribute
 * and if so call the attribute value function.
 *
 * uint16 value16       - 3 bytes (attribute)
 * value                - N bytes (value)
 */

static int32_t
server_prepare_attr_value_pair(
                provider_p const provider, uint16_t attr,
                uint8_t *buf, uint8_t const * const eob)
{
        profile_attr_create_p   cf = profile_get_attr(provider->profile, attr);
        int32_t                 len;

        if (cf == NULL)
                return (0); /* no attribute */

        if (buf + 3 > eob)
                return (-1);

        SDP_PUT8(SDP_DATA_UINT16, buf);
        SDP_PUT16(attr, buf);

        len = cf(buf, eob, (uint8_t const *) provider, sizeof(*provider));
        if (len < 0)
                return (-1);

        return (3 + len);
}

/*
 * seq16 value16        - 3 bytes
 *      attr value      - 3+ bytes
 *      [ attr value ]
 */

int32_t
server_prepare_attr_list(provider_p const provider,
                uint8_t const *req, uint8_t const * const req_end,
                uint8_t *rsp, uint8_t const * const rsp_end)
{
        uint8_t *ptr = rsp + 3;
        int32_t  type, hi, lo, len;

        if (ptr > rsp_end)
                return (-1);

        while (req < req_end) {
                SDP_GET8(type, req);

                switch (type) {
                case SDP_DATA_UINT16:
                        if (req + 2 > req_end)
                                return (-1);

                        SDP_GET16(lo, req);
                        hi = lo;
                        break;

                case SDP_DATA_UINT32:
                        if (req + 4 > req_end)
                                return (-1);

                        SDP_GET16(lo, req);
                        SDP_GET16(hi, req);
                        break;

                default:
                        return (-1);
                        /* NOT REACHED */
                }

                for (; lo <= hi; lo ++) {
                        len = server_prepare_attr_value_pair(provider, lo, ptr, rsp_end);
                        if (len < 0)
                                return (-1);

                        ptr += len;
                }
        }

        len = ptr - rsp; /* we put this much bytes in rsp */

        /* Fix SEQ16 header for the rsp */
        SDP_PUT8(SDP_DATA_SEQ16, rsp);
        SDP_PUT16(len - 3, rsp);

        return (len);
}

/*
 * Prepare SDP Service Attribute Response
 */

int32_t
server_prepare_service_attribute_response(server_p srv, int32_t fd)
{
        uint8_t const   *req = srv->req + sizeof(sdp_pdu_t);
        uint8_t const   *req_end = req + ((sdp_pdu_p)(srv->req))->len;
        uint8_t         *rsp = srv->fdidx[fd].rsp;
        uint8_t const   *rsp_end = rsp + NG_L2CAP_MTU_MAXIMUM;

        uint8_t         *ptr = NULL;
        provider_t      *provider = NULL;
        uint32_t         handle;
        int32_t          type, rsp_limit, aidlen, cslen, cs;

        /*
         * Minimal Service Attribute Request request
         *
         * value32              - 4 bytes ServiceRecordHandle
         * value16              - 2 bytes MaximumAttributeByteCount
         * seq8 len8            - 2 bytes
         *      uint16 value16  - 3 bytes AttributeIDList
         * value8               - 1 byte  ContinuationState
         */

        if (req_end - req < 12)
                return (SDP_ERROR_CODE_INVALID_REQUEST_SYNTAX);

        /* Get ServiceRecordHandle and MaximumAttributeByteCount */
        SDP_GET32(handle, req);
        SDP_GET16(rsp_limit, req);
        if (rsp_limit <= 0)
                return (SDP_ERROR_CODE_INVALID_REQUEST_SYNTAX);

        /* Get size of AttributeIDList */
        aidlen = 0;
        SDP_GET8(type, req);
        switch (type) {
        case SDP_DATA_SEQ8:
                SDP_GET8(aidlen, req);
                break;

        case SDP_DATA_SEQ16:
                SDP_GET16(aidlen, req);
                break;

        case SDP_DATA_SEQ32:
                SDP_GET32(aidlen, req);
                break;
        }
        if (aidlen <= 0)
                return (SDP_ERROR_CODE_INVALID_REQUEST_SYNTAX);

        ptr = (uint8_t *) req + aidlen;

        /* Get ContinuationState */
        if (ptr + 1 > req_end)
                return (SDP_ERROR_CODE_INVALID_REQUEST_SYNTAX);
                
        SDP_GET8(cslen, ptr);
        if (cslen != 0) {
                if (cslen != 2 || req_end - ptr != 2)
                        return (SDP_ERROR_CODE_INVALID_REQUEST_SYNTAX);

                SDP_GET16(cs, ptr);
        } else
                cs = 0;

        /* Process the request. First, check continuation state */
        if (srv->fdidx[fd].rsp_cs != cs)
                return (SDP_ERROR_CODE_INVALID_CONTINUATION_STATE);
        if (srv->fdidx[fd].rsp_size > 0)
                return (0);

        /* Lookup record handle */
        if ((provider = provider_by_handle(handle)) == NULL)
                return (SDP_ERROR_CODE_INVALID_SERVICE_RECORD_HANDLE);

        /*
         * Service Attribute Response format
         *
         * value16              - 2 bytes  AttributeListByteCount (not incl.)
         * seq8 len16           - 3 bytes
         *      attr value      - 3+ bytes AttributeList
         *      [ attr value ]
         */

        cs = server_prepare_attr_list(provider, req, req+aidlen, rsp, rsp_end);
        if (cs < 0)
                return (SDP_ERROR_CODE_INSUFFICIENT_RESOURCES);

        /* Set reply size (not counting PDU header and continuation state) */
        srv->fdidx[fd].rsp_limit = srv->fdidx[fd].omtu - sizeof(sdp_pdu_t) - 2;
        if (srv->fdidx[fd].rsp_limit > rsp_limit)
                srv->fdidx[fd].rsp_limit = rsp_limit;

        srv->fdidx[fd].rsp_size = cs;
        srv->fdidx[fd].rsp_cs = 0;

        return (0);
}

/*
 * Send SDP Service [Search] Attribute Response 
 */

int32_t
server_send_service_attribute_response(server_p srv, int32_t fd)
{
        uint8_t         *rsp = srv->fdidx[fd].rsp + srv->fdidx[fd].rsp_cs;
        uint8_t         *rsp_end = srv->fdidx[fd].rsp + srv->fdidx[fd].rsp_size;

        struct iovec    iov[4];
        sdp_pdu_t       pdu;
        uint16_t        bcount;
        uint8_t         cs[3];
        int32_t         size;

        /* First update continuation state  (assume we will send all data) */
        size = rsp_end - rsp;
        srv->fdidx[fd].rsp_cs += size;

        if (size + 1 > srv->fdidx[fd].rsp_limit) {
                /*
                 * We need to split out response. Add 3 more bytes for the
                 * continuation state and move rsp_end and rsp_cs backwards.
                 */

                while ((rsp_end - rsp) + 3 > srv->fdidx[fd].rsp_limit) {
                        rsp_end --;
                        srv->fdidx[fd].rsp_cs --;
                }

                cs[0] = 2;
                cs[1] = srv->fdidx[fd].rsp_cs >> 8;
                cs[2] = srv->fdidx[fd].rsp_cs & 0xff;
        } else
                cs[0] = 0;

        assert(rsp_end >= rsp);

        bcount = rsp_end - rsp;

        if (((sdp_pdu_p)(srv->req))->pid == SDP_PDU_SERVICE_ATTRIBUTE_REQUEST)
                pdu.pid = SDP_PDU_SERVICE_ATTRIBUTE_RESPONSE;
        else
                pdu.pid = SDP_PDU_SERVICE_SEARCH_ATTRIBUTE_RESPONSE;

        pdu.tid = ((sdp_pdu_p)(srv->req))->tid;
        pdu.len = htons(sizeof(bcount) + bcount + 1 + cs[0]);

        bcount = htons(bcount);

        iov[0].iov_base = &pdu;
        iov[0].iov_len = sizeof(pdu);

        iov[1].iov_base = &bcount;
        iov[1].iov_len = sizeof(bcount);

        iov[2].iov_base = rsp;
        iov[2].iov_len = rsp_end - rsp;

        iov[3].iov_base = cs;
        iov[3].iov_len = 1 + cs[0];

        do {
                size = writev(fd, (struct iovec const *) &iov, nitems(iov));
        } while (size < 0 && errno == EINTR);

        /* Check if we have sent (or failed to sent) last response chunk */
        if (srv->fdidx[fd].rsp_cs == srv->fdidx[fd].rsp_size) {
                srv->fdidx[fd].rsp_cs = 0;
                srv->fdidx[fd].rsp_size = 0;
                srv->fdidx[fd].rsp_limit = 0;
        }
        
        return ((size < 0)? errno : 0);
}