source: mainline/uspace/srv/inet/pdu.c@ bd8bfc5a

/*
 * Copyright (c) 2012 Jiri Svoboda
 * All rights reserved.
 *
 * 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
 */

/** @addtogroup inet
 * @{
 */
/**
 * @file
 * @brief
 */

#include <align.h>
#include <bitops.h>
#include <byteorder.h>
#include <errno.h>
#include <io/log.h>
#include <mem.h>
#include <stdlib.h>

#include "inet.h"
#include "inet_std.h"
#include "pdu.h"

/** Encode Internet PDU.
 *
 * XXX We should be encoding from packet, not from datagram.
 */
int inet_pdu_encode(inet_dgram_t *dgram, uint8_t ttl, int df, void **rdata,
    size_t *rsize)
{
        void *data;
        size_t size;
        ip_header_t *hdr;
        size_t hdr_size;
        size_t data_offs;

        hdr_size = sizeof(ip_header_t);
        size = hdr_size + dgram->size;
        data_offs = ROUND_UP(hdr_size, 4);

        data = calloc(size, 1);
        if (data == NULL)
                return ENOMEM;

        hdr = (ip_header_t *)data;
        hdr->ver_ihl = (4 << VI_VERSION_l) | (hdr_size / sizeof(uint32_t));
        hdr->tos = dgram->tos;
        hdr->tot_len = host2uint16_t_be(size);
        hdr->id = host2uint16_t_be(42);
        hdr->flags_foff = host2uint16_t_be(df ? BIT_V(uint16_t, FF_FLAG_DF) : 0);
        hdr->ttl = ttl;
        hdr->proto = 0;
        hdr->chksum = 0;
        hdr->src_addr = host2uint32_t_be(dgram->src.ipv4);
        hdr->dest_addr = host2uint32_t_be(dgram->dest.ipv4);

        memcpy((uint8_t *)data + data_offs, dgram->data, dgram->size);

        *rdata = data;
        *rsize = size;
        return EOK;
}

int inet_pdu_decode(void *data, size_t size, inet_dgram_t *dgram, uint8_t *ttl,
    int *df)
{
        ip_header_t *hdr;
        size_t tot_len;
        size_t data_offs;
        uint8_t version;
        uint16_t ident;

        log_msg(LVL_DEBUG, "inet_pdu_decode()");

        if (size < sizeof(ip_header_t)) {
                log_msg(LVL_DEBUG, "PDU too short (%zu)", size);
                return EINVAL;
        }

        hdr = (ip_header_t *)data;

        version = BIT_RANGE_EXTRACT(uint8_t, VI_VERSION_h, VI_VERSION_l,
            hdr->ver_ihl);
        if (version != 4) {
                log_msg(LVL_DEBUG, "Version (%d) != 4", version);
                return EINVAL;
        }

        tot_len = uint16_t_be2host(hdr->tot_len);
        if (tot_len < sizeof(ip_header_t)) {
                log_msg(LVL_DEBUG, "Total Length too small (%zu)", tot_len);
                return EINVAL;
        }

        if (tot_len > size) {
                log_msg(LVL_DEBUG, "Total Length = %zu > PDU size = %zu",
                        tot_len, size);
                return EINVAL;
        }

        ident = uint16_t_be2host(hdr->id);
        (void)ident;
        /* XXX Flags */
        /* XXX Fragment offset */
        /* XXX Protocol */
        /* XXX Checksum */

        dgram->src.ipv4 = uint32_t_be2host(hdr->src_addr);
        dgram->dest.ipv4 = uint32_t_be2host(hdr->dest_addr);
        dgram->tos = hdr->tos;
        *ttl = hdr->ttl;
        *df = (uint16_t_be2host(hdr->tos) & BIT_V(uint16_t, FF_FLAG_DF)) ?
            1 : 0;

        /* XXX IP options */
        data_offs = sizeof(uint32_t) * BIT_RANGE_EXTRACT(uint8_t, VI_IHL_h,
            VI_IHL_l, hdr->ver_ihl);

        dgram->size = tot_len - data_offs;
        dgram->data = calloc(dgram->size, 1);
        if (dgram->data == NULL) {
                log_msg(LVL_WARN, "Out of memory.");
                return ENOMEM;
        }

        memcpy(dgram->data, (uint8_t *)data + data_offs, dgram->size);

        return EOK;
}

/** @}
 */