source: mainline/uspace/lib/net/il/ip_client.c@ 069015f2

/*
 * Copyright (c) 2009 Lukas Mejdrech
 * 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 libnet
 * @{
 */

/** @file
 * IP client interface implementation.
 * @see ip_client.h
 */

#include <errno.h>
#include <sys/types.h>

#include <ip_client.h>
#include <packet_client.h>
#include <ip_header.h>

#include <net/packet.h>

/** Returns the IP header length.
 *
 * @param[in] packet    The packet.
 * @returns             The IP header length in bytes.
 * @returns             Zero if there is no IP header.
 */
size_t ip_client_header_length(packet_t packet)
{
        ip_header_ref header;

        header = (ip_header_ref) packet_get_data(packet);
        if (!header || (packet_get_data_length(packet) < sizeof(ip_header_t)))
                return 0;

        return IP_HEADER_LENGTH(header);
}

/** Constructs the IPv4 pseudo header.
 *
 * @param[in] protocol  The transport protocol.
 * @param[in] src       The source address.
 * @param[in] srclen    The source address length.
 * @param[in] dest      The destination address.
 * @param[in] destlen   The destination address length.
 * @param[in] data_length The data length to be set.
 * @param[out] header   The constructed IPv4 pseudo header.
 * @param[out] headerlen The length of the IP pseudo header in bytes.
 * @returns             EOK on success.
 * @returns             EBADMEM if the header and/or the headerlen parameter is
 *                      NULL.
 * @returns             EINVAL if the source address and/or the destination
 *                      address parameter is NULL.
 * @returns             EINVAL if the source address length is less than struct
 *                      sockaddr length.
 * @returns             EINVAL if the source address length differs from the
 *                      destination address length.
 * @returns             EINVAL if the source address family differs from the
 *                      destination family.
 * @returns             EAFNOSUPPORT if the address family is not supported.
 * @returns             ENOMEM if there is not enough memory left.
 */
int
ip_client_get_pseudo_header(ip_protocol_t protocol, struct sockaddr *src,
    socklen_t srclen, struct sockaddr *dest, socklen_t destlen,
    size_t data_length, void **header, size_t *headerlen)
{
        ipv4_pseudo_header_ref header_in;
        struct sockaddr_in *address_in;

        if (!header || !headerlen)
                return EBADMEM;

        if (!src || !dest || srclen <= 0 ||
            (((size_t) srclen < sizeof(struct sockaddr))) ||
            (srclen != destlen) || (src->sa_family != dest->sa_family)) {
                return EINVAL;
        }

        switch (src->sa_family) {
        case AF_INET:
                if (srclen != sizeof(struct sockaddr_in))
                        return EINVAL;
                
                *headerlen = sizeof(*header_in);
                header_in = (ipv4_pseudo_header_ref) malloc(*headerlen);
                if (!header_in)
                        return ENOMEM;

                bzero(header_in, *headerlen);
                address_in = (struct sockaddr_in *) dest;
                header_in->destination_address = address_in->sin_addr.s_addr;
                address_in = (struct sockaddr_in *) src;
                header_in->source_address = address_in->sin_addr.s_addr;
                header_in->protocol = protocol;
                header_in->data_length = htons(data_length);
                *header = header_in;
                return EOK;

        // TODO IPv6
/*      case AF_INET6:
                if (addrlen != sizeof(struct sockaddr_in6))
                        return EINVAL;

                address_in6 = (struct sockaddr_in6 *) addr;
                return EOK;
*/

        default:
                return EAFNOSUPPORT;
        }
}

/** Prepares the packet to be transfered via IP.
 *
 * The IP header is prefixed.
 *
 * @param[in,out] packet The packet to be prepared.
 * @param[in] protocol  The transport protocol.
 * @param[in] ttl       The time to live counter. The IPDEFTTL is set if zero.
 * @param[in] tos       The type of service.
 * @param[in] dont_fragment The value indicating whether fragmentation is
 *                      disabled.
 * @param[in] ipopt_length The prefixed IP options length in bytes.
 * @returns             EOK on success.
 * @returns             ENOMEM if there is not enough memory left in the packet.
 */
int
ip_client_prepare_packet(packet_t packet, ip_protocol_t protocol, ip_ttl_t ttl,
    ip_tos_t tos, int dont_fragment, size_t ipopt_length)
{
        ip_header_ref header;
        uint8_t *data;
        size_t padding;

        // compute the padding if IP options are set
        // multiple of 4 bytes
        padding =  ipopt_length % 4;
        if (padding) {
                padding = 4 - padding;
                ipopt_length += padding;
        }

        // prefix the header
        data = (uint8_t *) packet_prefix(packet, sizeof(ip_header_t) + padding);
        if (!data)
                return ENOMEM;

        // add the padding
        while (padding--)
                data[sizeof(ip_header_t) + padding] = IPOPT_NOOP;

        // set the header
        header = (ip_header_ref) data;
        header->header_length = IP_COMPUTE_HEADER_LENGTH(sizeof(ip_header_t) +
            ipopt_length);
        header->ttl = (ttl ? ttl : IPDEFTTL);
        header->tos = tos;
        header->protocol = protocol;

        if (dont_fragment)
                header->flags = IPFLAG_DONT_FRAGMENT;

        return EOK;
}

/** Processes the received IP packet.
 *
 * Fills set header fields.
 * Returns the prefixed IP header length.
 *
 * @param[in] packet    The received packet.
 * @param[out] protocol The transport protocol. May be NULL if not desired.
 * @param[out] ttl      The time to live counter. May be NULL if not desired.
 * @param[out] tos      The type of service. May be NULL if not desired.
 * @param[out] dont_fragment The value indicating whether the fragmentation is
 *                      disabled. May be NULL if not desired.
 * @param[out] ipopt_length The IP options length in bytes. May be NULL if not
 *                      desired.
 * @returns             The prefixed IP header length in bytes on success.
 * @returns             ENOMEM if the packet is too short to contain the IP
 *                      header.
 */
int
ip_client_process_packet(packet_t packet, ip_protocol_t *protocol,
    ip_ttl_t *ttl, ip_tos_t *tos, int *dont_fragment, size_t *ipopt_length)
{
        ip_header_ref header;

        header = (ip_header_ref) packet_get_data(packet);
        if (!header || (packet_get_data_length(packet) < sizeof(ip_header_t)))
                return ENOMEM;

        if (protocol)
                *protocol = header->protocol;
        if (ttl)
                *ttl = header->ttl;
        if (tos)
                *tos = header->tos;
        if (dont_fragment)
                *dont_fragment = header->flags & IPFLAG_DONT_FRAGMENT;
        if (ipopt_length) {
                *ipopt_length = IP_HEADER_LENGTH(header) - sizeof(ip_header_t);
                return sizeof(ip_header_t);
        } else {
                return IP_HEADER_LENGTH(header);
        }
}

/** Updates the IPv4 pseudo header data length field.
 *
 * @param[in,out] header The IPv4 pseudo header to be updated.
 * @param[in] headerlen The length of the IP pseudo header in bytes.
 * @param[in] data_length The data length to be set.
 * @returns             EOK on success.
 * @returns             EBADMEM if the header parameter is NULL.
 * @returns             EINVAL if the headerlen parameter is not IPv4 pseudo
 *                      header length.
 */
int
ip_client_set_pseudo_header_data_length(void *header, size_t headerlen,
    size_t data_length)
{
        ipv4_pseudo_header_ref header_in;

        if (!header)
                return EBADMEM;

        if (headerlen == sizeof(ipv4_pseudo_header_t)) {
                header_in = (ipv4_pseudo_header_ref) header;
                header_in->data_length = htons(data_length);
                return EOK;
        // TODO IPv6
        } else {
                return EINVAL;
        }
}

/** @}
 */