source: mainline/uspace/srv/net/il/ip/ip.c@ cc274f5a

/*
 * 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 ip
 * @{
 */

/** @file
 * IP module implementation.
 * @see arp.h
 */

#include "ip.h"
#include "ip_module.h"

#include <async.h>
#include <errno.h>
#include <fibril_synch.h>
#include <stdio.h>
#include <str.h>
#include <ipc/ipc.h>
#include <ipc/services.h>
#include <ipc/net.h>
#include <ipc/nil.h>
#include <ipc/il.h>
#include <ipc/ip.h>
#include <sys/types.h>
#include <byteorder.h>

#include <adt/measured_strings.h>
#include <adt/module_map.h>

#include <packet_client.h>
#include <net/socket_codes.h>
#include <net/in.h>
#include <net/in6.h>
#include <net/inet.h>
#include <net/modules.h>
#include <net/device.h>
#include <net/packet.h>
#include <net/icmp_codes.h>

#include <arp_interface.h>
#include <net_checksum.h>
#include <icmp_client.h>
#include <icmp_interface.h>
#include <il_interface.h>
#include <ip_client.h>
#include <ip_interface.h>
#include <ip_header.h>
#include <net_interface.h>
#include <nil_interface.h>
#include <tl_interface.h>
#include <packet_remote.h>
#include <il_local.h>

/** IP module name. */
#define NAME                    "ip"

/** IP version 4. */
#define IPV4                    4

/** Default network interface IP version. */
#define NET_DEFAULT_IPV         IPV4

/** Default network interface IP routing. */
#define NET_DEFAULT_IP_ROUTING  false

/** Minimum IP packet content. */
#define IP_MIN_CONTENT          576

/** ARP module name. */
#define ARP_NAME                "arp"

/** ARP module filename. */
#define ARP_FILENAME            "/srv/arp"

/** IP packet address length. */
#define IP_ADDR                 sizeof(struct sockaddr_in6)

/** IP packet prefix length. */
#define IP_PREFIX               sizeof(ip_header_t)

/** IP packet suffix length. */
#define IP_SUFFIX               0

/** IP packet maximum content length. */
#define IP_MAX_CONTENT          65535

/** The IP localhost address. */
#define IPV4_LOCALHOST_ADDRESS  htonl((127 << 24) + 1)

/** IP global data. */
ip_globals_t ip_globals;

DEVICE_MAP_IMPLEMENT(ip_netifs, ip_netif_t);
INT_MAP_IMPLEMENT(ip_protos, ip_proto_t);
GENERIC_FIELD_IMPLEMENT(ip_routes, ip_route_t);

/** Releases the packet and returns the result.
 *
 * @param[in] packet    The packet queue to be released.
 * @param[in] result    The result to be returned.
 * @return              The result parameter.
 */
static int ip_release_and_return(packet_t *packet, int result)
{
        pq_release_remote(ip_globals.net_phone, packet_get_id(packet));
        return result;
}

/** Returns the ICMP phone.
 *
 * Searches the registered protocols.
 *
 * @return              The found ICMP phone.
 * @return              ENOENT if the ICMP is not registered.
 */
static int ip_get_icmp_phone(void)
{
        ip_proto_t *proto;
        int phone;

        fibril_rwlock_read_lock(&ip_globals.protos_lock);
        proto = ip_protos_find(&ip_globals.protos, IPPROTO_ICMP);
        phone = proto ? proto->phone : ENOENT;
        fibril_rwlock_read_unlock(&ip_globals.protos_lock);
        return phone;
}

/** Prepares the ICMP notification packet.
 *
 * Releases additional packets and keeps only the first one.
 *
 * @param[in] packet    The packet or the packet queue to be reported as faulty.
 * @param[in] header    The first packet IP header. May be NULL.
 * @return              EOK on success.
 * @return              EINVAL if there are no data in the packet.
 * @return              EINVAL if the packet is a fragment.
 * @return              ENOMEM if the packet is too short to contain the IP
 *                      header.
 * @return              EAFNOSUPPORT if the address family is not supported.
 * @return              EPERM if the protocol is not allowed to send ICMP
 *                      notifications. The ICMP protocol itself.
 * @return              Other error codes as defined for the packet_set_addr().
 */
static int ip_prepare_icmp(packet_t *packet, ip_header_t *header)
{
        packet_t *next;
        struct sockaddr *dest;
        struct sockaddr_in dest_in;
        socklen_t addrlen;

        // detach the first packet and release the others
        next = pq_detach(packet);
        if (next)
                pq_release_remote(ip_globals.net_phone, packet_get_id(next));

        if (!header) {
                if (packet_get_data_length(packet) <= sizeof(ip_header_t))
                        return ENOMEM;

                // get header
                header = (ip_header_t *) packet_get_data(packet);
                if (!header)
                        return EINVAL;

        }

        // only for the first fragment
        if (IP_FRAGMENT_OFFSET(header))
                return EINVAL;

        // not for the ICMP protocol
        if (header->protocol == IPPROTO_ICMP)
                return EPERM;

        // set the destination address
        switch (header->version) {
        case IPVERSION:
                addrlen = sizeof(dest_in);
                bzero(&dest_in, addrlen);
                dest_in.sin_family = AF_INET;
                memcpy(&dest_in.sin_addr.s_addr, &header->source_address,
                    sizeof(header->source_address));
                dest = (struct sockaddr *) &dest_in;
                break;

        default:
                return EAFNOSUPPORT;
        }

        return packet_set_addr(packet, NULL, (uint8_t *) dest, addrlen);
}

/** Prepares the ICMP notification packet.
 *
 * Releases additional packets and keeps only the first one.
 * All packets are released on error.
 *
 * @param[in] error     The packet error service.
 * @param[in] packet    The packet or the packet queue to be reported as faulty.
 * @param[in] header    The first packet IP header. May be NULL.
 * @return              The found ICMP phone.
 * @return              EINVAL if the error parameter is set.
 * @return              EINVAL if the ICMP phone is not found.
 * @return              EINVAL if the ip_prepare_icmp() fails.
 */
static int
ip_prepare_icmp_and_get_phone(services_t error, packet_t *packet,
    ip_header_t *header)
{
        int phone;

        phone = ip_get_icmp_phone();
        if (error || (phone < 0) || ip_prepare_icmp(packet, header))
                return ip_release_and_return(packet, EINVAL);
        return phone;
}

/** Initializes the IP module.
 *
 * @param[in] client_connection The client connection processing function. The
 *                      module skeleton propagates its own one.
 * @return              EOK on success.
 * @return              ENOMEM if there is not enough memory left.
 */
int ip_initialize(async_client_conn_t client_connection)
{
        int rc;

        fibril_rwlock_initialize(&ip_globals.lock);
        fibril_rwlock_write_lock(&ip_globals.lock);
        fibril_rwlock_initialize(&ip_globals.protos_lock);
        fibril_rwlock_initialize(&ip_globals.netifs_lock);
        ip_globals.packet_counter = 0;
        ip_globals.gateway.address.s_addr = 0;
        ip_globals.gateway.netmask.s_addr = 0;
        ip_globals.gateway.gateway.s_addr = 0;
        ip_globals.gateway.netif = NULL;
        ip_globals.client_connection = client_connection;
        
        rc = ip_netifs_initialize(&ip_globals.netifs);
        if (rc != EOK)
                goto out;
        rc = ip_protos_initialize(&ip_globals.protos);
        if (rc != EOK)
                goto out;
        rc = modules_initialize(&ip_globals.modules);
        if (rc != EOK)
                goto out;
        rc = add_module(NULL, &ip_globals.modules, ARP_NAME, ARP_FILENAME,
            SERVICE_ARP, 0, arp_connect_module);

out:
        fibril_rwlock_write_unlock(&ip_globals.lock);

        return rc;
}

/** Initializes a new network interface specific data.
 *
 * Connects to the network interface layer module, reads the netif
 * configuration, starts an ARP module if needed and sets the netif routing
 * table.
 * 
 * The device identifier and the nil service has to be set.
 *
 * @param[in,out] ip_netif Network interface specific data.
 * @return              EOK on success.
 * @return              ENOTSUP if DHCP is configured.
 * @return              ENOTSUP if IPv6 is configured.
 * @return              EINVAL if any of the addresses is invalid.
 * @return              EINVAL if the used ARP module is not known.
 * @return              ENOMEM if there is not enough memory left.
 * @return              Other error codes as defined for the
 *                      net_get_device_conf_req() function.
 * @return              Other error codes as defined for the bind_service()
 *                      function.
 * @return              Other error codes as defined for the specific
 *                      arp_device_req() function.
 * @return              Other error codes as defined for the
 *                      nil_packet_size_req() function.
 */
static int ip_netif_initialize(ip_netif_t *ip_netif)
{
        measured_string_t names[] = {
                {
                        (char *) "IPV",
                        3
                },
                {
                        (char *) "IP_CONFIG",
                        9
                },
                {
                        (char *) "IP_ADDR",
                        7
                },
                {
                        (char *) "IP_NETMASK",
                        10
                },
                {
                        (char *) "IP_GATEWAY",
                        10
                },
                {
                        (char *) "IP_BROADCAST",
                        12
                },
                {
                        (char *) "ARP",
                        3
                },
                {
                        (char *) "IP_ROUTING",
                        10
                }
        };
        measured_string_t *configuration;
        size_t count = sizeof(names) / sizeof(measured_string_t);
        char *data;
        measured_string_t address;
        ip_route_t *route;
        in_addr_t gateway;
        int index;
        int rc;

        ip_netif->arp = NULL;
        route = NULL;
        ip_netif->ipv = NET_DEFAULT_IPV;
        ip_netif->dhcp = false;
        ip_netif->routing = NET_DEFAULT_IP_ROUTING;
        configuration = &names[0];

        // get configuration
        rc = net_get_device_conf_req(ip_globals.net_phone, ip_netif->device_id,
            &configuration, count, &data);
        if (rc != EOK)
                return rc;
        
        if (configuration) {
                if (configuration[0].value)
                        ip_netif->ipv = strtol(configuration[0].value, NULL, 0);

                ip_netif->dhcp = !str_lcmp(configuration[1].value, "dhcp",
                    configuration[1].length);
                
                if (ip_netif->dhcp) {
                        // TODO dhcp
                        net_free_settings(configuration, data);
                        return ENOTSUP;
                } else if (ip_netif->ipv == IPV4) {
                        route = (ip_route_t *) malloc(sizeof(ip_route_t));
                        if (!route) {
                                net_free_settings(configuration, data);
                                return ENOMEM;
                        }
                        route->address.s_addr = 0;
                        route->netmask.s_addr = 0;
                        route->gateway.s_addr = 0;
                        route->netif = ip_netif;
                        index = ip_routes_add(&ip_netif->routes, route);
                        if (index < 0) {
                                net_free_settings(configuration, data);
                                free(route);
                                return index;
                        }
                        
                        if ((inet_pton(AF_INET, configuration[2].value,
                            (uint8_t *) &route->address.s_addr) != EOK) ||
                            (inet_pton(AF_INET, configuration[3].value,
                            (uint8_t *) &route->netmask.s_addr) != EOK) ||
                            (inet_pton(AF_INET, configuration[4].value,
                            (uint8_t *) &gateway.s_addr) == EINVAL) ||
                            (inet_pton(AF_INET, configuration[5].value,
                            (uint8_t *) &ip_netif->broadcast.s_addr) == EINVAL))
                            {
                                net_free_settings(configuration, data);
                                return EINVAL;
                        }
                } else {
                        // TODO ipv6 in separate module
                        net_free_settings(configuration, data);
                        return ENOTSUP;
                }

                if (configuration[6].value) {
                        ip_netif->arp = get_running_module(&ip_globals.modules,
                            configuration[6].value);
                        if (!ip_netif->arp) {
                                printf("Failed to start the arp %s\n",
                                    configuration[6].value);
                                net_free_settings(configuration, data);
                                return EINVAL;
                        }
                }
                if (configuration[7].value)
                        ip_netif->routing = (configuration[7].value[0] == 'y');

                net_free_settings(configuration, data);
        }

        // binds the netif service which also initializes the device
        ip_netif->phone = nil_bind_service(ip_netif->service,
            (sysarg_t) ip_netif->device_id, SERVICE_IP,
            ip_globals.client_connection);
        if (ip_netif->phone < 0) {
                printf("Failed to contact the nil service %d\n",
                    ip_netif->service);
                return ip_netif->phone;
        }

        // has to be after the device netif module initialization
        if (ip_netif->arp) {
                if (route) {
                        address.value = (char *) &route->address.s_addr;
                        address.length = sizeof(in_addr_t);
                        
                        rc = arp_device_req(ip_netif->arp->phone,
                            ip_netif->device_id, SERVICE_IP, ip_netif->service,
                            &address);
                        if (rc != EOK)
                                return rc;
                } else {
                        ip_netif->arp = 0;
                }
        }

        // get packet dimensions
        rc = nil_packet_size_req(ip_netif->phone, ip_netif->device_id,
            &ip_netif->packet_dimension);
        if (rc != EOK)
                return rc;
        
        if (ip_netif->packet_dimension.content < IP_MIN_CONTENT) {
                printf("Maximum transmission unit %zu bytes is too small, at "
                    "least %d bytes are needed\n",
                    ip_netif->packet_dimension.content, IP_MIN_CONTENT);
                ip_netif->packet_dimension.content = IP_MIN_CONTENT;
        }

        index = ip_netifs_add(&ip_globals.netifs, ip_netif->device_id, ip_netif);
        if (index < 0)
                return index;
        
        if (gateway.s_addr) {
                // the default gateway
                ip_globals.gateway.address.s_addr = 0;
                ip_globals.gateway.netmask.s_addr = 0;
                ip_globals.gateway.gateway.s_addr = gateway.s_addr;
                ip_globals.gateway.netif = ip_netif;
        }

        return EOK;
}

/** Updates the device content length according to the new MTU value.
 *
 * @param[in] device_id The device identifier.
 * @param[in] mtu       The new mtu value.
 * @return              EOK on success.
 * @return              ENOENT if device is not found.
 */
static int ip_mtu_changed_message(device_id_t device_id, size_t mtu)
{
        ip_netif_t *netif;

        fibril_rwlock_write_lock(&ip_globals.netifs_lock);
        netif = ip_netifs_find(&ip_globals.netifs, device_id);
        if (!netif) {
                fibril_rwlock_write_unlock(&ip_globals.netifs_lock);
                return ENOENT;
        }
        netif->packet_dimension.content = mtu;
        fibril_rwlock_write_unlock(&ip_globals.netifs_lock);

        printf("%s: Device %d changed MTU to %zu\n", NAME, device_id, mtu);

        return EOK;
}

/** Updates the device state.
 *
 * @param[in] device_id The device identifier.
 * @param[in] state     The new state value.
 * @return              EOK on success.
 * @return              ENOENT if device is not found.
 */
static int ip_device_state_message(device_id_t device_id, device_state_t state)
{
        ip_netif_t *netif;

        fibril_rwlock_write_lock(&ip_globals.netifs_lock);
        // find the device
        netif = ip_netifs_find(&ip_globals.netifs, device_id);
        if (!netif) {
                fibril_rwlock_write_unlock(&ip_globals.netifs_lock);
                return ENOENT;
        }
        netif->state = state;
        fibril_rwlock_write_unlock(&ip_globals.netifs_lock);

        printf("%s: Device %d changed state to %d\n", NAME, device_id, state);

        return EOK;
}


/** Prefixes a middle fragment header based on the last fragment header to the
 * packet.
 *
 * @param[in] packet    The packet to be prefixed.
 * @param[in] last      The last header to be copied.
 * @return              The prefixed middle header.
 * @return              NULL on error.
 */
static ip_header_t *
ip_create_middle_header(packet_t *packet, ip_header_t *last)
{
        ip_header_t *middle;

        middle = (ip_header_t *) packet_suffix(packet, IP_HEADER_LENGTH(last));
        if (!middle)
                return NULL;
        memcpy(middle, last, IP_HEADER_LENGTH(last));
        middle->flags |= IPFLAG_MORE_FRAGMENTS;
        return middle;
}

/** Copies the fragment header.
 *
 * Copies only the header itself and relevant IP options.
 *
 * @param[out] last     The created header.
 * @param[in] first     The original header to be copied.
 */
static void ip_create_last_header(ip_header_t *last, ip_header_t *first)
{
        ip_option_t *option;
        size_t next;
        size_t length;

        // copy first itself
        memcpy(last, first, sizeof(ip_header_t));
        length = sizeof(ip_header_t);
        next = sizeof(ip_header_t);

        // process all ip options
        while (next < first->header_length) {
                option = (ip_option_t *) (((uint8_t *) first) + next);
                // skip end or noop
                if ((option->type == IPOPT_END) ||
                    (option->type == IPOPT_NOOP)) {
                        next++;
                } else {
                        // copy if told so or skip
                        if (IPOPT_COPIED(option->type)) {
                                memcpy(((uint8_t *) last) + length,
                                    ((uint8_t *) first) + next, option->length);
                                length += option->length;
                        }
                        // next option
                        next += option->length;
                }
        }

        // align 4 byte boundary
        if (length % 4) {
                bzero(((uint8_t *) last) + length, 4 - (length % 4));
                last->header_length = length / 4 + 1;
        } else {
                last->header_length = length / 4;
        }

        last->header_checksum = 0;
}

/** Prepares the outgoing packet or the packet queue.
 *
 * The packet queue is a fragmented packet
 * Updates the first packet's IP header.
 * Prefixes the additional packets with fragment headers.
 *
 * @param[in] source    The source address.
 * @param[in] dest      The destination address.
 * @param[in,out] packet The packet to be sent.
 * @param[in] destination The destination hardware address.
 * @return              EOK on success.
 * @return              EINVAL if the packet is too small to contain the IP
 *                      header.
 * @return              EINVAL if the packet is too long than the IP allows.
 * @return              ENOMEM if there is not enough memory left.
 * @return              Other error codes as defined for the packet_set_addr()
 *                      function.
 */
static int
ip_prepare_packet(in_addr_t *source, in_addr_t dest, packet_t *packet,
    measured_string_t *destination)
{
        size_t length;
        ip_header_t *header;
        ip_header_t *last_header;
        ip_header_t *middle_header;
        packet_t *next;
        int rc;

        length = packet_get_data_length(packet);
        if ((length < sizeof(ip_header_t)) || (length > IP_MAX_CONTENT))
                return EINVAL;

        header = (ip_header_t *) packet_get_data(packet);
        if (destination) {
                rc = packet_set_addr(packet, NULL, (uint8_t *) destination->value,
                    destination->length);
        } else {
                rc = packet_set_addr(packet, NULL, NULL, 0);
        }
        if (rc != EOK)
                return rc;
        
        header->version = IPV4;
        header->fragment_offset_high = 0;
        header->fragment_offset_low = 0;
        header->header_checksum = 0;
        if (source)
                header->source_address = source->s_addr;
        header->destination_address = dest.s_addr;

        fibril_rwlock_write_lock(&ip_globals.lock);
        ip_globals.packet_counter++;
        header->identification = htons(ip_globals.packet_counter);
        fibril_rwlock_write_unlock(&ip_globals.lock);

        if (pq_next(packet)) {
                last_header = (ip_header_t *) malloc(IP_HEADER_LENGTH(header));
                if (!last_header)
                        return ENOMEM;
                ip_create_last_header(last_header, header);
                next = pq_next(packet);
                while (pq_next(next)) {
                        middle_header = (ip_header_t *) packet_prefix(next,
                            IP_HEADER_LENGTH(last_header));
                        if (!middle_header) {
                                free(last_header);
                                return ENOMEM;
                        }

                        memcpy(middle_header, last_header,
                            IP_HEADER_LENGTH(last_header));
                        header->flags |= IPFLAG_MORE_FRAGMENTS;
                        middle_header->total_length =
                            htons(packet_get_data_length(next));
                        middle_header->fragment_offset_high =
                            IP_COMPUTE_FRAGMENT_OFFSET_HIGH(length);
                        middle_header->fragment_offset_low =
                            IP_COMPUTE_FRAGMENT_OFFSET_LOW(length);
                        middle_header->header_checksum =
                            IP_HEADER_CHECKSUM(middle_header);
                        if (destination) {
                                rc = packet_set_addr(next, NULL,
                                    (uint8_t *) destination->value,
                                    destination->length);
                                if (rc != EOK) {
                                        free(last_header);
                                        return rc;
                                }
                        }
                        length += packet_get_data_length(next);
                        next = pq_next(next);
                }

                middle_header = (ip_header_t *) packet_prefix(next,
                    IP_HEADER_LENGTH(last_header));
                if (!middle_header) {
                        free(last_header);
                        return ENOMEM;
                }

                memcpy(middle_header, last_header,
                    IP_HEADER_LENGTH(last_header));
                middle_header->total_length =
                    htons(packet_get_data_length(next));
                middle_header->fragment_offset_high =
                    IP_COMPUTE_FRAGMENT_OFFSET_HIGH(length);
                middle_header->fragment_offset_low =
                    IP_COMPUTE_FRAGMENT_OFFSET_LOW(length);
                middle_header->header_checksum =
                    IP_HEADER_CHECKSUM(middle_header);
                if (destination) {
                        rc = packet_set_addr(next, NULL,
                            (uint8_t *) destination->value,
                            destination->length);
                        if (rc != EOK) {
                                free(last_header);
                                return rc;
                        }
                }
                length += packet_get_data_length(next);
                free(last_header);
                header->flags |= IPFLAG_MORE_FRAGMENTS;
        }

        header->total_length = htons(length);
        // unnecessary for all protocols
        header->header_checksum = IP_HEADER_CHECKSUM(header);

        return EOK;
}

/** Fragments the packet from the end.
 *
 * @param[in] packet    The packet to be fragmented.
 * @param[in,out] new_packet The new packet fragment.
 * @param[in,out] header The original packet header.
 * @param[in,out] new_header The new packet fragment header.
 * @param[in] length    The new fragment length.
 * @param[in] src       The source address.
 * @param[in] dest      The destiantion address.
 * @param[in] addrlen   The address length.
 * @return              EOK on success.
 * @return              ENOMEM if the target packet is too small.
 * @return              Other error codes as defined for the packet_set_addr()
 *                      function.
 * @return              Other error codes as defined for the pq_insert_after()
 *                      function.
 */
static int
ip_fragment_packet_data(packet_t *packet, packet_t *new_packet,
    ip_header_t *header, ip_header_t *new_header, size_t length,
    const struct sockaddr *src, const struct sockaddr *dest, socklen_t addrlen)
{
        void *data;
        size_t offset;
        int rc;

        data = packet_suffix(new_packet, length);
        if (!data)
                return ENOMEM;

        memcpy(data, ((void *) header) + IP_TOTAL_LENGTH(header) - length,
            length);
        
        rc = packet_trim(packet, 0, length);
        if (rc != EOK)
                return rc;
        
        header->total_length = htons(IP_TOTAL_LENGTH(header) - length);
        new_header->total_length = htons(IP_HEADER_LENGTH(new_header) + length);
        offset = IP_FRAGMENT_OFFSET(header) + IP_HEADER_DATA_LENGTH(header);
        new_header->fragment_offset_high =
            IP_COMPUTE_FRAGMENT_OFFSET_HIGH(offset);
        new_header->fragment_offset_low =
            IP_COMPUTE_FRAGMENT_OFFSET_LOW(offset);
        new_header->header_checksum = IP_HEADER_CHECKSUM(new_header);
        
        rc = packet_set_addr(new_packet, (const uint8_t *) src,
            (const uint8_t *) dest, addrlen);
        if (rc != EOK)
                return rc;

        return pq_insert_after(packet, new_packet);
}

/** Checks the packet length and fragments it if needed.
 *
 * The new fragments are queued before the original packet.
 *
 * @param[in,out] packet The packet to be checked.
 * @param[in] length    The maximum packet length.
 * @param[in] prefix    The minimum prefix size.
 * @param[in] suffix    The minimum suffix size.
 * @param[in] addr_len  The minimum address length.
 * @return              EOK on success.
 * @return              EINVAL if the packet_get_addr() function fails.
 * @return              EINVAL if the packet does not contain the IP header.
 * @return              EPERM if the packet needs to be fragmented and the
 *                      fragmentation is not allowed.
 * @return              ENOMEM if there is not enough memory left.
 * @return              ENOMEM if there is no packet available.
 * @return              ENOMEM if the packet is too small to contain the IP
 *                      header.
 * @return              Other error codes as defined for the packet_trim()
 *                      function.
 * @return              Other error codes as defined for the
 *                      ip_create_middle_header() function.
 * @return              Other error codes as defined for the
 *                      ip_fragment_packet_data() function.
 */
static int
ip_fragment_packet(packet_t *packet, size_t length, size_t prefix, size_t suffix,
    socklen_t addr_len)
{
        packet_t *new_packet;
        ip_header_t *header;
        ip_header_t *middle_header;
        ip_header_t *last_header;
        struct sockaddr *src;
        struct sockaddr *dest;
        socklen_t addrlen;
        int result;
        int rc;

        result = packet_get_addr(packet, (uint8_t **) &src, (uint8_t **) &dest);
        if (result <= 0)
                return EINVAL;

        addrlen = (socklen_t) result;
        if (packet_get_data_length(packet) <= sizeof(ip_header_t))
                return ENOMEM;

        // get header
        header = (ip_header_t *) packet_get_data(packet);
        if (!header)
                return EINVAL;

        // fragmentation forbidden?
        if(header->flags & IPFLAG_DONT_FRAGMENT)
                return EPERM;

        // create the last fragment
        new_packet = packet_get_4_remote(ip_globals.net_phone, prefix, length,
            suffix, ((addrlen > addr_len) ? addrlen : addr_len));
        if (!new_packet)
                return ENOMEM;

        // allocate as much as originally
        last_header = (ip_header_t *) packet_suffix(new_packet,
            IP_HEADER_LENGTH(header));
        if (!last_header)
                return ip_release_and_return(packet, ENOMEM);

        ip_create_last_header(last_header, header);

        // trim the unused space
        rc = packet_trim(new_packet, 0,
            IP_HEADER_LENGTH(header) - IP_HEADER_LENGTH(last_header));
        if (rc != EOK)
                return ip_release_and_return(packet, rc);

        // biggest multiple of 8 lower than content
        // TODO even fragmentation?
        length = length & ~0x7;
        
        rc = ip_fragment_packet_data(packet, new_packet, header, last_header,
            ((IP_HEADER_DATA_LENGTH(header) -
            ((length - IP_HEADER_LENGTH(header)) & ~0x7)) %
            ((length - IP_HEADER_LENGTH(last_header)) & ~0x7)),
            src, dest, addrlen);
        if (rc != EOK)
                return ip_release_and_return(packet, rc);

        // mark the first as fragmented
        header->flags |= IPFLAG_MORE_FRAGMENTS;

        // create middle framgents
        while (IP_TOTAL_LENGTH(header) > length) {
                new_packet = packet_get_4_remote(ip_globals.net_phone, prefix,
                    length, suffix,
                    ((addrlen >= addr_len) ? addrlen : addr_len));
                if (!new_packet)
                        return ENOMEM;

                middle_header = ip_create_middle_header(new_packet,
                    last_header);
                if (!middle_header)
                        return ip_release_and_return(packet, ENOMEM);

                rc = ip_fragment_packet_data(packet, new_packet, header,
                    middle_header,
                    (length - IP_HEADER_LENGTH(middle_header)) & ~0x7,
                    src, dest, addrlen);
                if (rc != EOK)
                        return ip_release_and_return(packet, rc);
        }

        // finish the first fragment
        header->header_checksum = IP_HEADER_CHECKSUM(header);

        return EOK;
}

/** Checks the packet queue lengths and fragments the packets if needed.
 *
 * The ICMP_FRAG_NEEDED error notification may be sent if the packet needs to
 * be fragmented and the fragmentation is not allowed.
 *
 * @param[in,out] packet The packet or the packet queue to be checked.
 * @param[in] prefix    The minimum prefix size.
 * @param[in] content   The maximum content size.
 * @param[in] suffix    The minimum suffix size.
 * @param[in] addr_len  The minimum address length.
 * @param[in] error     The error module service.
 * @return              The packet or the packet queue of the allowed length.
 * @return              NULL if there are no packets left.
 */
static packet_t *
ip_split_packet(packet_t *packet, size_t prefix, size_t content, size_t suffix,
    socklen_t addr_len, services_t error)
{
        size_t length;
        packet_t *next;
        packet_t *new_packet;
        int result;
        int phone;

        next = packet;
        // check all packets
        while (next) {
                length = packet_get_data_length(next);
                
                if (length <= content) {
                        next = pq_next(next);
                        continue;
                }

                // too long
                result = ip_fragment_packet(next, content, prefix,
                    suffix, addr_len);
                if (result != EOK) {
                        new_packet = pq_detach(next);
                        if (next == packet) {
                                // the new first packet of the queue
                                packet = new_packet;
                        }
                        // fragmentation needed?
                        if (result == EPERM) {
                                phone = ip_prepare_icmp_and_get_phone(
                                    error, next, NULL);
                                if (phone >= 0) {
                                        // fragmentation necessary ICMP
                                        icmp_destination_unreachable_msg(phone,
                                            ICMP_FRAG_NEEDED, content, next);
                                }
                        } else {
                                pq_release_remote(ip_globals.net_phone,
                                    packet_get_id(next));
                        }

                        next = new_packet;
                        continue;
                }

                next = pq_next(next);
        }

        return packet;
}

/** Sends the packet or the packet queue via the specified route.
 *
 * The ICMP_HOST_UNREACH error notification may be sent if route hardware
 * destination address is found.
 *
 * @param[in,out] packet The packet to be sent.
 * @param[in] netif     The target network interface.
 * @param[in] route     The target route.
 * @param[in] src       The source address.
 * @param[in] dest      The destination address.
 * @param[in] error     The error module service.
 * @return              EOK on success.
 * @return              Other error codes as defined for the arp_translate_req()
 *                      function.
 * @return              Other error codes as defined for the ip_prepare_packet()
 *                      function.
 */
static int
ip_send_route(packet_t *packet, ip_netif_t *netif, ip_route_t *route,
    in_addr_t *src, in_addr_t dest, services_t error)
{
        measured_string_t destination;
        measured_string_t *translation;
        char *data;
        int phone;
        int rc;

        // get destination hardware address
        if (netif->arp && (route->address.s_addr != dest.s_addr)) {
                destination.value = route->gateway.s_addr ?
                    (char *) &route->gateway.s_addr : (char *) &dest.s_addr;
                destination.length = sizeof(dest.s_addr);

                rc = arp_translate_req(netif->arp->phone, netif->device_id,
                    SERVICE_IP, &destination, &translation, &data);
                if (rc != EOK) {
                        pq_release_remote(ip_globals.net_phone,
                            packet_get_id(packet));
                        return rc;
                }

                if (!translation || !translation->value) {
                        if (translation) {
                                free(translation);
                                free(data);
                        }
                        phone = ip_prepare_icmp_and_get_phone(error, packet,
                            NULL);
                        if (phone >= 0) {
                                // unreachable ICMP if no routing
                                icmp_destination_unreachable_msg(phone,
                                    ICMP_HOST_UNREACH, 0, packet);
                        }
                        return EINVAL;
                }

        } else {
                translation = NULL;
        }

        rc = ip_prepare_packet(src, dest, packet, translation);
        if (rc != EOK) {
                pq_release_remote(ip_globals.net_phone, packet_get_id(packet));
        } else {
                packet = ip_split_packet(packet, netif->packet_dimension.prefix,
                    netif->packet_dimension.content,
                    netif->packet_dimension.suffix,
                    netif->packet_dimension.addr_len, error);
                if (packet) {
                        nil_send_msg(netif->phone, netif->device_id, packet,
                            SERVICE_IP);
                }
        }

        if (translation) {
                free(translation);
                free(data);
        }

        return rc;
}

/** Searches the network interfaces if there is a suitable route.
 *
 * @param[in] netif     The network interface to be searched for routes. May be
 *                      NULL.
 * @param[in] destination The destination address.
 * @return              The found route.
 * @return              NULL if no route was found.
 */
static ip_route_t *
ip_netif_find_route(ip_netif_t *netif, in_addr_t destination)
{
        int index;
        ip_route_t *route;

        if (!netif)
                return NULL;

        // start with the first one - the direct route
        for (index = 0; index < ip_routes_count(&netif->routes); index++) {
                route = ip_routes_get_index(&netif->routes, index);
                if (route &&
                    ((route->address.s_addr & route->netmask.s_addr) ==
                    (destination.s_addr & route->netmask.s_addr))) {
                        return route;
                }
        }

        return NULL;
}

/** Searches all network interfaces if there is a suitable route.
 *
 * @param[in] destination The destination address.
 * @return              The found route.
 * @return              NULL if no route was found.
 */
static ip_route_t *ip_find_route(in_addr_t destination) {
        int index;
        ip_route_t *route;
        ip_netif_t *netif;

        // start with the last netif - the newest one
        index = ip_netifs_count(&ip_globals.netifs) - 1;
        while (index >= 0) {
                netif = ip_netifs_get_index(&ip_globals.netifs, index);
                if (netif && (netif->state == NETIF_ACTIVE)) {
                        route = ip_netif_find_route(netif, destination);
                        if (route)
                                return route;
                }
                index--;
        }

        return &ip_globals.gateway;
}

/** Returns the network interface's IP address.
 *
 * @param[in] netif     The network interface.
 * @return              The IP address.
 * @return              NULL if no IP address was found.
 */
static in_addr_t *ip_netif_address(ip_netif_t *netif)
{
        ip_route_t *route;

        route = ip_routes_get_index(&netif->routes, 0);
        return route ? &route->address : NULL;
}

/** Registers the transport layer protocol.
 *
 * The traffic of this protocol will be supplied using either the receive
 * function or IPC message.
 *
 * @param[in] protocol  The transport layer module protocol.
 * @param[in] service   The transport layer module service.
 * @param[in] phone     The transport layer module phone.
 * @param[in] received_msg The receiving function.
 * @return              EOK on success.
 * @return              EINVAL if the protocol parameter and/or the service
 *                      parameter is zero.
 * @return              EINVAL if the phone parameter is not a positive number
 *                      and the tl_receive_msg is NULL.
 * @return              ENOMEM if there is not enough memory left.
 */
static int
ip_register(int protocol, services_t service, int phone,
    tl_received_msg_t received_msg)
{
        ip_proto_t *proto;
        int index;

        if (!protocol || !service || ((phone < 0) && !received_msg))
                return EINVAL;

        proto = (ip_proto_t *) malloc(sizeof(ip_protos_t));
        if (!proto)
                return ENOMEM;

        proto->protocol = protocol;
        proto->service = service;
        proto->phone = phone;
        proto->received_msg = received_msg;

        fibril_rwlock_write_lock(&ip_globals.protos_lock);
        index = ip_protos_add(&ip_globals.protos, proto->protocol, proto);
        if (index < 0) {
                fibril_rwlock_write_unlock(&ip_globals.protos_lock);
                free(proto);
                return index;
        }
        fibril_rwlock_write_unlock(&ip_globals.protos_lock);

        printf("%s: Protocol registered (protocol: %d, phone: %d)\n",
            NAME, proto->protocol, proto->phone);

        return EOK;
}

static int
ip_device_req_local(int il_phone, device_id_t device_id, services_t netif)
{
        ip_netif_t *ip_netif;
        ip_route_t *route;
        int index;
        int rc;

        ip_netif = (ip_netif_t *) malloc(sizeof(ip_netif_t));
        if (!ip_netif)
                return ENOMEM;

        rc = ip_routes_initialize(&ip_netif->routes);
        if (rc != EOK) {
                free(ip_netif);
                return rc;
        }

        ip_netif->device_id = device_id;
        ip_netif->service = netif;
        ip_netif->state = NETIF_STOPPED;

        fibril_rwlock_write_lock(&ip_globals.netifs_lock);

        rc = ip_netif_initialize(ip_netif);
        if (rc != EOK) {
                fibril_rwlock_write_unlock(&ip_globals.netifs_lock);
                ip_routes_destroy(&ip_netif->routes);
                free(ip_netif);
                return rc;
        }
        if (ip_netif->arp)
                ip_netif->arp->usage++;

        // print the settings
        printf("%s: Device registered (id: %d, phone: %d, ipv: %d, conf: %s)\n",
            NAME, ip_netif->device_id, ip_netif->phone, ip_netif->ipv,
            ip_netif->dhcp ? "dhcp" : "static");
        
        // TODO ipv6 addresses
        
        char address[INET_ADDRSTRLEN];
        char netmask[INET_ADDRSTRLEN];
        char gateway[INET_ADDRSTRLEN];
        
        for (index = 0; index < ip_routes_count(&ip_netif->routes); index++) {
                route = ip_routes_get_index(&ip_netif->routes, index);
                if (route) {
                        inet_ntop(AF_INET, (uint8_t *) &route->address.s_addr,
                            address, INET_ADDRSTRLEN);
                        inet_ntop(AF_INET, (uint8_t *) &route->netmask.s_addr,
                            netmask, INET_ADDRSTRLEN);
                        inet_ntop(AF_INET, (uint8_t *) &route->gateway.s_addr,
                            gateway, INET_ADDRSTRLEN);
                        printf("%s: Route %d (address: %s, netmask: %s, "
                            "gateway: %s)\n", NAME, index, address, netmask,
                            gateway);
                }
        }
        
        inet_ntop(AF_INET, (uint8_t *) &ip_netif->broadcast.s_addr, address,
            INET_ADDRSTRLEN);
        fibril_rwlock_write_unlock(&ip_globals.netifs_lock);

        printf("%s: Broadcast (%s)\n", NAME, address);

        return EOK;
}

static int
ip_send_msg_local(int il_phone, device_id_t device_id, packet_t *packet,
    services_t sender, services_t error)
{
        int addrlen;
        ip_netif_t *netif;
        ip_route_t *route;
        struct sockaddr *addr;
        struct sockaddr_in *address_in;
        in_addr_t *dest;
        in_addr_t *src;
        int phone;
        int rc;

        // addresses in the host byte order
        // should be the next hop address or the target destination address
        addrlen = packet_get_addr(packet, NULL, (uint8_t **) &addr);
        if (addrlen < 0)
                return ip_release_and_return(packet, addrlen);
        if ((size_t) addrlen < sizeof(struct sockaddr))
                return ip_release_and_return(packet, EINVAL);

        switch (addr->sa_family) {
        case AF_INET:
                if (addrlen != sizeof(struct sockaddr_in))
                        return ip_release_and_return(packet, EINVAL);
                address_in = (struct sockaddr_in *) addr;
                dest = &address_in->sin_addr;
                if (!dest->s_addr)
                        dest->s_addr = IPV4_LOCALHOST_ADDRESS;
                break;
        case AF_INET6:
        default:
                return ip_release_and_return(packet, EAFNOSUPPORT);
        }

        netif = NULL;
        route = NULL;
        fibril_rwlock_read_lock(&ip_globals.netifs_lock);

        // device specified?
        if (device_id > 0) {
                netif = ip_netifs_find(&ip_globals.netifs, device_id);
                route = ip_netif_find_route(netif, * dest);
                if (netif && !route && (ip_globals.gateway.netif == netif))
                        route = &ip_globals.gateway;
        }

        if (!route) {
                route = ip_find_route(*dest);
                netif = route ? route->netif : NULL;
        }
        if (!netif || !route) {
                fibril_rwlock_read_unlock(&ip_globals.netifs_lock);
                phone = ip_prepare_icmp_and_get_phone(error, packet, NULL);
                if (phone >= 0) {
                        // unreachable ICMP if no routing
                        icmp_destination_unreachable_msg(phone,
                            ICMP_NET_UNREACH, 0, packet);
                }
                return ENOENT;
        }

        if (error) {
                // do not send for broadcast, anycast packets or network
                // broadcast
                if (!dest->s_addr || !(~dest->s_addr) ||
                    !(~((dest->s_addr & ~route->netmask.s_addr) |
                    route->netmask.s_addr)) ||
                    (!(dest->s_addr & ~route->netmask.s_addr))) {
                        return ip_release_and_return(packet, EINVAL);
                }
        }

        // if the local host is the destination
        if ((route->address.s_addr == dest->s_addr) &&
            (dest->s_addr != IPV4_LOCALHOST_ADDRESS)) {
                // find the loopback device to deliver
                dest->s_addr = IPV4_LOCALHOST_ADDRESS;
                route = ip_find_route(*dest);
                netif = route ? route->netif : NULL;
                if (!netif || !route) {
                        fibril_rwlock_read_unlock(&ip_globals.netifs_lock);
                        phone = ip_prepare_icmp_and_get_phone(error, packet,
                            NULL);
                        if (phone >= 0) {
                                // unreachable ICMP if no routing
                                icmp_destination_unreachable_msg(phone,
                                    ICMP_HOST_UNREACH, 0, packet);
                        }
                        return ENOENT;
                }
        }
        
        src = ip_netif_address(netif);
        if (!src) {
                fibril_rwlock_read_unlock(&ip_globals.netifs_lock);
                return ip_release_and_return(packet, ENOENT);
        }

        rc = ip_send_route(packet, netif, route, src, *dest, error);
        fibril_rwlock_read_unlock(&ip_globals.netifs_lock);

        return rc;
}

/** Returns the device packet dimensions for sending.
 *
 * @param[in] phone     The service module phone.
 * @param[in] message   The service specific message.
 * @param[in] device_id The device identifier.
 * @param[out] addr_len The minimum reserved address length.
 * @param[out] prefix   The minimum reserved prefix size.
 * @param[out] content  The maximum content size.
 * @param[out] suffix   The minimum reserved suffix size.
 * @return              EOK on success.
 */
static int
ip_packet_size_message(device_id_t device_id, size_t *addr_len, size_t *prefix,
    size_t *content, size_t *suffix)
{
        ip_netif_t *netif;
        int index;

        if (!addr_len || !prefix || !content || !suffix)
                return EBADMEM;

        *content = IP_MAX_CONTENT - IP_PREFIX;
        fibril_rwlock_read_lock(&ip_globals.netifs_lock);
        if (device_id < 0) {
                *addr_len = IP_ADDR;
                *prefix = 0;
                *suffix = 0;

                for (index = ip_netifs_count(&ip_globals.netifs) - 1;
                    index >= 0; index--) {
                        netif = ip_netifs_get_index(&ip_globals.netifs, index);
                        if (!netif)
                                continue;
                        
                        if (netif->packet_dimension.addr_len > *addr_len)
                                *addr_len = netif->packet_dimension.addr_len;
                        
                        if (netif->packet_dimension.prefix > *prefix)
                                *prefix = netif->packet_dimension.prefix;
                                
                        if (netif->packet_dimension.suffix > *suffix)
                                *suffix = netif->packet_dimension.suffix;
                }

                *prefix = *prefix + IP_PREFIX;
                *suffix = *suffix + IP_SUFFIX;
        } else {
                netif = ip_netifs_find(&ip_globals.netifs, device_id);
                if (!netif) {
                        fibril_rwlock_read_unlock(&ip_globals.netifs_lock);
                        return ENOENT;
                }

                *addr_len = (netif->packet_dimension.addr_len > IP_ADDR) ?
                    netif->packet_dimension.addr_len : IP_ADDR;
                *prefix = netif->packet_dimension.prefix + IP_PREFIX;
                *suffix = netif->packet_dimension.suffix + IP_SUFFIX;
        }
        fibril_rwlock_read_unlock(&ip_globals.netifs_lock);

        return EOK;
}

/** Returns the packet destination address from the IP header.
 *
 * @param[in] header    The packet IP header to be read.
 * @return              The packet destination address.
 */
static in_addr_t ip_get_destination(ip_header_t *header)
{
        in_addr_t destination;

        // TODO search set ipopt route?
        destination.s_addr = header->destination_address;
        return destination;
}

/** Delivers the packet to the local host.
 *
 * The packet is either passed to another module or released on error.
 * The ICMP_PROT_UNREACH error notification may be sent if the protocol is not
 * found.
 *
 * @param[in] device_id The source device identifier.
 * @param[in] packet    The packet to be delivered.
 * @param[in] header    The first packet IP header. May be NULL.
 * @param[in] error     The packet error service.
 * @return              EOK on success.
 * @return              ENOTSUP if the packet is a fragment.
 * @return              EAFNOSUPPORT if the address family is not supported.
 * @return              ENOENT if the target protocol is not found.
 * @return              Other error codes as defined for the packet_set_addr()
 *                      function.
 * @return              Other error codes as defined for the packet_trim()
 *                      function.
 * @return              Other error codes as defined for the protocol specific
 *                      tl_received_msg() function.
 */
static int
ip_deliver_local(device_id_t device_id, packet_t *packet, ip_header_t *header,
    services_t error)
{
        ip_proto_t *proto;
        int phone;
        services_t service;
        tl_received_msg_t received_msg;
        struct sockaddr *src;
        struct sockaddr *dest;
        struct sockaddr_in src_in;
        struct sockaddr_in dest_in;
        socklen_t addrlen;
        int rc;

        if ((header->flags & IPFLAG_MORE_FRAGMENTS) ||
            IP_FRAGMENT_OFFSET(header)) {
                // TODO fragmented
                return ENOTSUP;
        }
        
        switch (header->version) {
        case IPVERSION:
                addrlen = sizeof(src_in);
                bzero(&src_in, addrlen);
                src_in.sin_family = AF_INET;
                memcpy(&dest_in, &src_in, addrlen);
                memcpy(&src_in.sin_addr.s_addr, &header->source_address,
                    sizeof(header->source_address));
                memcpy(&dest_in.sin_addr.s_addr, &header->destination_address,
                    sizeof(header->destination_address));
                src = (struct sockaddr *) &src_in;
                dest = (struct sockaddr *) &dest_in;
                break;

        default:
                return ip_release_and_return(packet, EAFNOSUPPORT);
        }

        rc = packet_set_addr(packet, (uint8_t *) src, (uint8_t *) dest,
            addrlen);
        if (rc != EOK)
                return ip_release_and_return(packet, rc);

        // trim padding if present
        if (!error &&
            (IP_TOTAL_LENGTH(header) < packet_get_data_length(packet))) {
                rc = packet_trim(packet, 0,
                    packet_get_data_length(packet) - IP_TOTAL_LENGTH(header));
                if (rc != EOK)
                        return ip_release_and_return(packet, rc);
        }

        fibril_rwlock_read_lock(&ip_globals.protos_lock);

        proto = ip_protos_find(&ip_globals.protos, header->protocol);
        if (!proto) {
                fibril_rwlock_read_unlock(&ip_globals.protos_lock);
                phone = ip_prepare_icmp_and_get_phone(error, packet, header);
                if (phone >= 0) {
                        // unreachable ICMP
                        icmp_destination_unreachable_msg(phone,
                            ICMP_PROT_UNREACH, 0, packet);
                }
                return ENOENT;
        }

        if (proto->received_msg) {
                service = proto->service;
                received_msg = proto->received_msg;
                fibril_rwlock_read_unlock(&ip_globals.protos_lock);
                rc = received_msg(device_id, packet, service, error);
        } else {
                rc = tl_received_msg(proto->phone, device_id, packet,
                    proto->service, error);
                fibril_rwlock_read_unlock(&ip_globals.protos_lock);
        }

        return rc;
}

/** Processes the received packet.
 *
 * The packet is either passed to another module or released on error.
 *
 * The ICMP_PARAM_POINTER error notification may be sent if the checksum is
 * invalid.
 * The ICMP_EXC_TTL error notification may be sent if the TTL is less than two.
 * The ICMP_HOST_UNREACH error notification may be sent if no route was found.
 * The ICMP_HOST_UNREACH error notification may be sent if the packet is for
 * another host and the routing is disabled.
 *
 * @param[in] device_id The source device identifier.
 * @param[in] packet    The received packet to be processed.
 * @return              EOK on success.
 * @return              EINVAL if the TTL is less than two.
 * @return              EINVAL if the checksum is invalid.
 * @return              EAFNOSUPPORT if the address family is not supported.
 * @return              ENOENT if no route was found.
 * @return              ENOENT if the packet is for another host and the routing
 *                      is disabled.
 */
static int
ip_process_packet(device_id_t device_id, packet_t *packet)
{
        ip_header_t *header;
        in_addr_t dest;
        ip_route_t *route;
        int phone;
        struct sockaddr *addr;
        struct sockaddr_in addr_in;
        socklen_t addrlen;
        int rc;

        header = (ip_header_t *) packet_get_data(packet);
        if (!header)
                return ip_release_and_return(packet, ENOMEM);

        // checksum
        if ((header->header_checksum) &&
            (IP_HEADER_CHECKSUM(header) != IP_CHECKSUM_ZERO)) {
                phone = ip_prepare_icmp_and_get_phone(0, packet, header);
                if (phone >= 0) {
                        // checksum error ICMP
                        icmp_parameter_problem_msg(phone, ICMP_PARAM_POINTER,
                            ((size_t) ((void *) &header->header_checksum)) -
                            ((size_t) ((void *) header)), packet);
                }
                return EINVAL;
        }

        if (header->ttl <= 1) {
                phone = ip_prepare_icmp_and_get_phone(0, packet, header);
                if (phone >= 0) {
                        // ttl exceeded ICMP
                        icmp_time_exceeded_msg(phone, ICMP_EXC_TTL, packet);
                }
                return EINVAL;
        }

        // process ipopt and get destination
        dest = ip_get_destination(header);

        // set the addrination address
        switch (header->version) {
        case IPVERSION:
                addrlen = sizeof(addr_in);
                bzero(&addr_in, addrlen);
                addr_in.sin_family = AF_INET;
                memcpy(&addr_in.sin_addr.s_addr, &dest, sizeof(dest));
                addr = (struct sockaddr *) &addr_in;
                break;

        default:
                return ip_release_and_return(packet, EAFNOSUPPORT);
        }

        rc = packet_set_addr(packet, NULL, (uint8_t *) &addr, addrlen);
        if (rc != EOK)
                return rc;

        route = ip_find_route(dest);
        if (!route) {
                phone = ip_prepare_icmp_and_get_phone(0, packet, header);
                if (phone >= 0) {
                        // unreachable ICMP
                        icmp_destination_unreachable_msg(phone,
                            ICMP_HOST_UNREACH, 0, packet);
                }
                return ENOENT;
        }

        if (route->address.s_addr == dest.s_addr) {
                // local delivery
                return ip_deliver_local(device_id, packet, header, 0);
        }

        if (route->netif->routing) {
                header->ttl--;
                return ip_send_route(packet, route->netif, route, NULL, dest,
                    0);
        }

        phone = ip_prepare_icmp_and_get_phone(0, packet, header);
        if (phone >= 0) {
                // unreachable ICMP if no routing
                icmp_destination_unreachable_msg(phone, ICMP_HOST_UNREACH, 0,
                    packet);
        }
        
        return ENOENT;
}

static int
ip_add_route_req_local(int ip_phone, device_id_t device_id, in_addr_t address,
    in_addr_t netmask, in_addr_t gateway)
{
        ip_route_t *route;
        ip_netif_t *netif;
        int index;

        fibril_rwlock_write_lock(&ip_globals.netifs_lock);

        netif = ip_netifs_find(&ip_globals.netifs, device_id);
        if (!netif) {
                fibril_rwlock_write_unlock(&ip_globals.netifs_lock);
                return ENOENT;
        }

        route = (ip_route_t *) malloc(sizeof(ip_route_t));
        if (!route) {
                fibril_rwlock_write_unlock(&ip_globals.netifs_lock);
                return ENOMEM;
        }

        route->address.s_addr = address.s_addr;
        route->netmask.s_addr = netmask.s_addr;
        route->gateway.s_addr = gateway.s_addr;
        route->netif = netif;
        index = ip_routes_add(&netif->routes, route);
        if (index < 0)
                free(route);

        fibril_rwlock_write_unlock(&ip_globals.netifs_lock);
        
        return index;
}

static int
ip_set_gateway_req_local(int ip_phone, device_id_t device_id, in_addr_t gateway)
{
        ip_netif_t *netif;

        fibril_rwlock_write_lock(&ip_globals.netifs_lock);

        netif = ip_netifs_find(&ip_globals.netifs, device_id);
        if (!netif) {
                fibril_rwlock_write_unlock(&ip_globals.netifs_lock);
                return ENOENT;
        }

        ip_globals.gateway.address.s_addr = 0;
        ip_globals.gateway.netmask.s_addr = 0;
        ip_globals.gateway.gateway.s_addr = gateway.s_addr;
        ip_globals.gateway.netif = netif;
        
        fibril_rwlock_write_unlock(&ip_globals.netifs_lock);
        
        return EOK;
}

/** Notify the IP module about the received error notification packet.
 *
 * @param[in] ip_phone  The IP module phone used for (semi)remote calls.
 * @param[in] device_id The device identifier.
 * @param[in] packet    The received packet or the received packet queue.
 * @param[in] target    The target internetwork module service to be
 *                      delivered to.
 * @param[in] error     The packet error reporting service. Prefixes the
 *                      received packet.
 * @return              EOK on success.
 *
 */
static int
ip_received_error_msg_local(int ip_phone, device_id_t device_id,
    packet_t *packet, services_t target, services_t error)
{
        uint8_t *data;
        int offset;
        icmp_type_t type;
        icmp_code_t code;
        ip_netif_t *netif;
        measured_string_t address;
        ip_route_t *route;
        ip_header_t *header;

        switch (error) {
        case SERVICE_ICMP:
                offset = icmp_client_process_packet(packet, &type, &code, NULL,
                    NULL);
                if (offset < 0)
                        return ip_release_and_return(packet, ENOMEM);

                data = packet_get_data(packet);
                header = (ip_header_t *)(data + offset);

                // destination host unreachable?
                if ((type != ICMP_DEST_UNREACH) ||
                    (code != ICMP_HOST_UNREACH)) {
                        // no, something else
                        break;
                }

                fibril_rwlock_read_lock(&ip_globals.netifs_lock);

                netif = ip_netifs_find(&ip_globals.netifs, device_id);
                if (!netif || !netif->arp) {
                        fibril_rwlock_read_unlock(&ip_globals.netifs_lock);
                        break;
                }

                route = ip_routes_get_index(&netif->routes, 0);

                // from the same network?
                if (route && ((route->address.s_addr & route->netmask.s_addr) ==
                    (header->destination_address & route->netmask.s_addr))) {
                        // clear the ARP mapping if any
                        address.value = (char *) &header->destination_address;
                        address.length = sizeof(header->destination_address);
                        arp_clear_address_req(netif->arp->phone,
                            netif->device_id, SERVICE_IP, &address);
                }

                fibril_rwlock_read_unlock(&ip_globals.netifs_lock);
                break;

        default:
                return ip_release_and_return(packet, ENOTSUP);
        }

        return ip_deliver_local(device_id, packet, header, error);
}

static int
ip_get_route_req_local(int ip_phone, ip_protocol_t protocol,
    const struct sockaddr *destination, socklen_t addrlen,
    device_id_t *device_id, void **header, size_t *headerlen)
{
        struct sockaddr_in *address_in;
        in_addr_t *dest;
        in_addr_t *src;
        ip_route_t *route;
        ipv4_pseudo_header_t *header_in;

        if (!destination || (addrlen <= 0))
                return EINVAL;

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

        if ((size_t) addrlen < sizeof(struct sockaddr))
                return EINVAL;

        switch (destination->sa_family) {
        case AF_INET:
                if (addrlen != sizeof(struct sockaddr_in))
                        return EINVAL;
                address_in = (struct sockaddr_in *) destination;
                dest = &address_in->sin_addr;
                if (!dest->s_addr)
                        dest->s_addr = IPV4_LOCALHOST_ADDRESS;
                break;

        case AF_INET6:
        default:
                return EAFNOSUPPORT;
        }

        fibril_rwlock_read_lock(&ip_globals.lock);
        route = ip_find_route(*dest);
        // if the local host is the destination
        if (route && (route->address.s_addr == dest->s_addr) &&
            (dest->s_addr != IPV4_LOCALHOST_ADDRESS)) {
                // find the loopback device to deliver
                dest->s_addr = IPV4_LOCALHOST_ADDRESS;
                route = ip_find_route(*dest);
        }

        if (!route || !route->netif) {
                fibril_rwlock_read_unlock(&ip_globals.lock);
                return ENOENT;
        }

        *device_id = route->netif->device_id;
        src = ip_netif_address(route->netif);
        fibril_rwlock_read_unlock(&ip_globals.lock);

        *headerlen = sizeof(*header_in);
        header_in = (ipv4_pseudo_header_t *) malloc(*headerlen);
        if (!header_in)
                return ENOMEM;

        bzero(header_in, *headerlen);
        header_in->destination_address = dest->s_addr;
        header_in->source_address = src->s_addr;
        header_in->protocol = protocol;
        header_in->data_length = 0;
        *header = header_in;

        return EOK;
}

/** Processes the received IP packet or the packet queue one by one.
 *
 * The packet is either passed to another module or released on error.
 *
 * @param[in] device_id The source device identifier.
 * @param[in,out] packet The received packet.
 * @return              EOK on success and the packet is no longer needed.
 * @return              EINVAL if the packet is too small to carry the IP
 *                      packet.
 * @return              EINVAL if the received address lengths differs from the
 *                      registered values.
 * @return              ENOENT if the device is not found in the cache.
 * @return              ENOENT if the protocol for the device is not found in
 *                      the cache.
 * @return              ENOMEM if there is not enough memory left.
 */
static int ip_receive_message(device_id_t device_id, packet_t *packet)
{
        packet_t *next;

        do {
                next = pq_detach(packet);
                ip_process_packet(device_id, packet);
                packet = next;
        } while (packet);

        return EOK;
}

/** Processes the IP message.
 *
 * @param[in] callid    The message identifier.
 * @param[in] call      The message parameters.
 * @param[out] answer   The message answer parameters.
 * @param[out] answer_count The last parameter for the actual answer in the
 *                      answer parameter.
 * @return              EOK on success.
 * @return              ENOTSUP if the message is not known.
 *
 * @see ip_interface.h
 * @see il_interface.h
 * @see IS_NET_IP_MESSAGE()
 */
int
ip_message_standalone(ipc_callid_t callid, ipc_call_t *call, ipc_call_t *answer,
    int *answer_count)
{
        packet_t *packet;
        struct sockaddr *addr;
        size_t addrlen;
        size_t prefix;
        size_t suffix;
        size_t content;
        void *header;
        size_t headerlen;
        device_id_t device_id;
        int rc;
        
        *answer_count = 0;
        switch (IPC_GET_IMETHOD(*call)) {
        case IPC_M_PHONE_HUNGUP:
                return EOK;
        
        case IPC_M_CONNECT_TO_ME:
                return ip_register(IL_GET_PROTO(call), IL_GET_SERVICE(call),
                    IPC_GET_PHONE(call), NULL);
        
        case NET_IL_DEVICE:
                return ip_device_req_local(0, IPC_GET_DEVICE(call),
                    IPC_GET_SERVICE(call));
        
        case NET_IL_SEND:
                rc = packet_translate_remote(ip_globals.net_phone, &packet,
                    IPC_GET_PACKET(call));
                if (rc != EOK)
                        return rc;
                return ip_send_msg_local(0, IPC_GET_DEVICE(call), packet, 0,
                    IPC_GET_ERROR(call));
        
        case NET_IL_DEVICE_STATE:
                return ip_device_state_message(IPC_GET_DEVICE(call),
                    IPC_GET_STATE(call));
        
        case NET_IL_RECEIVED:
                rc = packet_translate_remote(ip_globals.net_phone, &packet,
                    IPC_GET_PACKET(call));
                if (rc != EOK)
                        return rc;
                return ip_receive_message(IPC_GET_DEVICE(call), packet);
        
        case NET_IP_RECEIVED_ERROR:
                rc = packet_translate_remote(ip_globals.net_phone, &packet,
                    IPC_GET_PACKET(call));
                if (rc != EOK)
                        return rc;
                return ip_received_error_msg_local(0, IPC_GET_DEVICE(call),
                    packet, IPC_GET_TARGET(call), IPC_GET_ERROR(call));
        
        case NET_IP_ADD_ROUTE:
                return ip_add_route_req_local(0, IPC_GET_DEVICE(call),
                    IP_GET_ADDRESS(call), IP_GET_NETMASK(call),
                    IP_GET_GATEWAY(call));

        case NET_IP_SET_GATEWAY:
                return ip_set_gateway_req_local(0, IPC_GET_DEVICE(call),
                    IP_GET_GATEWAY(call));

        case NET_IP_GET_ROUTE:
                rc = async_data_write_accept((void **) &addr, false, 0, 0, 0,
                    &addrlen);
                if (rc != EOK)
                        return rc;
                
                rc = ip_get_route_req_local(0, IP_GET_PROTOCOL(call), addr,
                    (socklen_t) addrlen, &device_id, &header, &headerlen);
                if (rc != EOK)
                        return rc;
                
                IPC_SET_DEVICE(answer, device_id);
                IP_SET_HEADERLEN(answer, headerlen);
                
                *answer_count = 2;
                
                rc = data_reply(&headerlen, sizeof(headerlen));
                if (rc == EOK)
                        rc = data_reply(header, headerlen);
                        
                free(header);
                return rc;
        
        case NET_IL_PACKET_SPACE:
                rc = ip_packet_size_message(IPC_GET_DEVICE(call), &addrlen,
                    &prefix, &content, &suffix);
                if (rc != EOK)
                        return rc;
                
                IPC_SET_ADDR(answer, addrlen);
                IPC_SET_PREFIX(answer, prefix);
                IPC_SET_CONTENT(answer, content);
                IPC_SET_SUFFIX(answer, suffix);
                *answer_count = 4;
                return EOK;
        
        case NET_IL_MTU_CHANGED:
                return ip_mtu_changed_message(IPC_GET_DEVICE(call),
                    IPC_GET_MTU(call));
        }
        
        return ENOTSUP;
}

/** Default thread for new connections.
 *
 * @param[in] iid       The initial message identifier.
 * @param[in] icall     The initial message call structure.
 */
static void il_client_connection(ipc_callid_t iid, ipc_call_t *icall)
{
        /*
         * Accept the connection
         *  - Answer the first IPC_M_CONNECT_ME_TO call.
         */
        ipc_answer_0(iid, EOK);
        
        while (true) {
                ipc_call_t answer;
                int answer_count;
                
                /* Clear the answer structure */
                refresh_answer(&answer, &answer_count);
                
                /* Fetch the next message */
                ipc_call_t call;
                ipc_callid_t callid = async_get_call(&call);
                
                /* Process the message */
                int res = il_module_message_standalone(callid, &call, &answer,
                    &answer_count);
                
                /*
                 * End if told to either by the message or the processing
                 * result.
                 */
                if ((IPC_GET_IMETHOD(call) == IPC_M_PHONE_HUNGUP) ||
                    (res == EHANGUP)) {
                        return;
                }
                
                /* Answer the message */
                answer_call(callid, res, &answer, answer_count);
        }
}

/** Starts the module.
 *
 * @return EOK on success.
 * @return Other error codes as defined for each specific module start function.
 */
int main(int argc, char *argv[])
{
        int rc;
        
        /* Start the module */
        rc = il_module_start_standalone(il_client_connection);
        return rc;
}

/** @}
 */