source: mainline/uspace/srv/net/udp/assoc.c

/*
 * Copyright (c) 2015 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 udp
 * @{
 */

/**
 * @file UDP associations
 */

#include <adt/list.h>
#include <errno.h>
#include <stdbool.h>
#include <fibril_synch.h>
#include <inet/endpoint.h>
#include <io/log.h>
#include <nettl/amap.h>
#include <stdlib.h>

#include "assoc.h"
#include "msg.h"
#include "pdu.h"
#include "udp_type.h"

static LIST_INITIALIZE(assoc_list);
static FIBRIL_MUTEX_INITIALIZE(assoc_list_lock);
static amap_t *amap;

static udp_assoc_t *udp_assoc_find_ref(inet_ep2_t *);
static errno_t udp_assoc_queue_msg(udp_assoc_t *, inet_ep2_t *, udp_msg_t *);
static udp_assocs_dep_t *assocs_dep;

/** Initialize associations. */
errno_t udp_assocs_init(udp_assocs_dep_t *dep)
{
        errno_t rc;

        rc = amap_create(&amap);
        if (rc != EOK) {
                assert(rc == ENOMEM);
                return ENOMEM;
        }

        assocs_dep = dep;
        return EOK;
}

/** Finalize associations. */
void udp_assocs_fini(void)
{
        assert(list_empty(&assoc_list));

        amap_destroy(amap);
        amap = NULL;
}

/** Create new association structure.
 *
 * @param epp           Endpoint pair (will be copied)
 * @param cb            Callbacks
 * @param cb_arg        Callback argument
 * @return              New association or NULL
 */
udp_assoc_t *udp_assoc_new(inet_ep2_t *epp, udp_assoc_cb_t *cb, void *cb_arg)
{
        udp_assoc_t *assoc = NULL;

        /* Allocate association structure */
        assoc = calloc(1, sizeof(udp_assoc_t));
        if (assoc == NULL)
                goto error;

        fibril_mutex_initialize(&assoc->lock);

        /* One for the user */
        refcount_init(&assoc->refcnt);

        /* Initialize receive queue */
        list_initialize(&assoc->rcv_queue);
        fibril_condvar_initialize(&assoc->rcv_queue_cv);

        if (epp != NULL)
                assoc->ident = *epp;

        assoc->cb = cb;
        assoc->cb_arg = cb_arg;
        return assoc;
error:
        return NULL;
}

/** Destroy association structure.
 *
 * Association structure should be destroyed when the folowing conditions
 * are met:
 * (1) user has deleted the association
 * (2) nobody is holding references to the association
 *
 * This happens when @a assoc->refcnt is zero as we count (1)
 * as an extra reference.
 *
 * @param assoc         Association
 */
static void udp_assoc_free(udp_assoc_t *assoc)
{
        log_msg(LOG_DEFAULT, LVL_DEBUG, "%s: udp_assoc_free(%p)", assoc->name, assoc);

        while (!list_empty(&assoc->rcv_queue)) {
                link_t *link = list_first(&assoc->rcv_queue);
                udp_rcv_queue_entry_t *rqe = list_get_instance(link,
                    udp_rcv_queue_entry_t, link);
                list_remove(link);

                udp_msg_delete(rqe->msg);
                free(rqe);
        }

        free(assoc);
}

/** Add reference to association.
 *
 * Increase association reference count by one.
 *
 * @param assoc         Association
 */
void udp_assoc_addref(udp_assoc_t *assoc)
{
        log_msg(LOG_DEFAULT, LVL_DEBUG, "%s: upd_assoc_addref(%p)", assoc->name, assoc);
        refcount_up(&assoc->refcnt);
}

/** Remove reference from association.
 *
 * Decrease association reference count by one.
 *
 * @param assoc         Association
 */
void udp_assoc_delref(udp_assoc_t *assoc)
{
        log_msg(LOG_DEFAULT, LVL_DEBUG, "%s: udp_assoc_delref(%p)", assoc->name, assoc);

        if (refcount_down(&assoc->refcnt))
                udp_assoc_free(assoc);
}

/** Delete association.
 *
 * The caller promises not make no further references to @a assoc.
 * UDP will free @a assoc eventually.
 *
 * @param assoc         Association
 */
void udp_assoc_delete(udp_assoc_t *assoc)
{
        log_msg(LOG_DEFAULT, LVL_DEBUG, "%s: udp_assoc_delete(%p)", assoc->name, assoc);

        assert(assoc->deleted == false);
        assoc->deleted = true;
        udp_assoc_delref(assoc);
}

/** Enlist association.
 *
 * Add association to the association map.
 */
errno_t udp_assoc_add(udp_assoc_t *assoc)
{
        inet_ep2_t aepp;
        errno_t rc;

        udp_assoc_addref(assoc);
        fibril_mutex_lock(&assoc_list_lock);

        rc = amap_insert(amap, &assoc->ident, assoc, af_allow_system, &aepp);
        if (rc != EOK) {
                udp_assoc_delref(assoc);
                fibril_mutex_unlock(&assoc_list_lock);
                return rc;
        }

        assoc->ident = aepp;
        list_append(&assoc->link, &assoc_list);
        fibril_mutex_unlock(&assoc_list_lock);

        return EOK;
}

/** Delist association.
 *
 * Remove association from the association map.
 */
void udp_assoc_remove(udp_assoc_t *assoc)
{
        fibril_mutex_lock(&assoc_list_lock);
        amap_remove(amap, &assoc->ident);
        list_remove(&assoc->link);
        fibril_mutex_unlock(&assoc_list_lock);
        udp_assoc_delref(assoc);
}

/** Set IP link in association.
 *
 * @param assoc         Association
 * @param iplink        IP link
 */
void udp_assoc_set_iplink(udp_assoc_t *assoc, service_id_t iplink)
{
        log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_set_iplink(%p, %zu)",
            assoc, iplink);
        fibril_mutex_lock(&assoc->lock);
        assoc->ident.local_link = iplink;
        fibril_mutex_unlock(&assoc->lock);
}

/** Send message to association.
 *
 * @param assoc         Association
 * @param remote        Remote endpoint or inet_addr_any/inet_port_any
 *                      not to override association's remote endpoint
 * @param msg           Message
 *
 * @return              EOK on success
 *                      EINVAL if remote endpoint is not set
 *                      ENOMEM if out of resources
 *                      EIO if no route to destination exists
 */
errno_t udp_assoc_send(udp_assoc_t *assoc, inet_ep_t *remote, udp_msg_t *msg)
{
        inet_ep2_t epp;
        errno_t rc;

        log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_send(%p, %p, %p)",
            assoc, remote, msg);

        /* @a remote can be used to override the remote endpoint */
        epp = assoc->ident;
        if (!inet_addr_is_any(&remote->addr) &&
            remote->port != inet_port_any)
                epp.remote = *remote;

        log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_send - check addr any");

        if ((inet_addr_is_any(&epp.remote.addr)) ||
            (epp.remote.port == inet_port_any))
                return EINVAL;

        /* This association has no local address set. Need to determine one. */
        log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_send - check no local addr");
        if (inet_addr_is_any(&epp.local.addr) && !assoc->nolocal) {
                log_msg(LOG_DEFAULT, LVL_DEBUG, "Determine local address.");
                rc = (*assocs_dep->get_srcaddr)(&epp.remote.addr, 0,
                    &epp.local.addr);
                if (rc != EOK) {
                        log_msg(LOG_DEFAULT, LVL_DEBUG, "Cannot determine "
                            "local address.");
                        return EINVAL;
                }
        }

        log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_send - check version");

        if (!inet_addr_is_any(&epp.local.addr) &&
            epp.remote.addr.version != epp.local.addr.version)
                return EINVAL;

        log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_send - transmit");
        rc = (*assocs_dep->transmit_msg)(&epp, msg);

        if (rc != EOK)
                return EIO;

        log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_send - success");
        return EOK;
}

/** Get a received message.
 *
 * Pull one message from the association's receive queue.
 */
errno_t udp_assoc_recv(udp_assoc_t *assoc, udp_msg_t **msg, inet_ep_t *remote)
{
        link_t *link;
        udp_rcv_queue_entry_t *rqe;

        log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_recv()");

        fibril_mutex_lock(&assoc->lock);
        while (list_empty(&assoc->rcv_queue) && !assoc->reset) {
                log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_recv() - waiting");
                fibril_condvar_wait(&assoc->rcv_queue_cv, &assoc->lock);
        }

        if (assoc->reset) {
                log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_recv() - association was reset");
                fibril_mutex_unlock(&assoc->lock);
                return ENXIO;
        }

        log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_recv() - got a message");
        link = list_first(&assoc->rcv_queue);
        rqe = list_get_instance(link, udp_rcv_queue_entry_t, link);
        list_remove(link);
        fibril_mutex_unlock(&assoc->lock);

        *msg = rqe->msg;
        *remote = rqe->epp.remote;
        free(rqe);

        return EOK;
}

/** Message received.
 *
 * Find the association to which the message belongs and queue it.
 */
void udp_assoc_received(inet_ep2_t *repp, udp_msg_t *msg)
{
        udp_assoc_t *assoc;
        errno_t rc;

        log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_received(%p, %p)", repp, msg);

        assoc = udp_assoc_find_ref(repp);
        if (assoc == NULL) {
                log_msg(LOG_DEFAULT, LVL_DEBUG, "No association found. Message dropped.");
                /* XXX Generate ICMP error. */
                /* XXX Might propagate error directly by error return. */
                udp_msg_delete(msg);
                return;
        }

        if (0) {
                rc = udp_assoc_queue_msg(assoc, repp, msg);
                if (rc != EOK) {
                        log_msg(LOG_DEFAULT, LVL_DEBUG, "Out of memory. Message dropped.");
                        /* XXX Generate ICMP error? */
                }
        }

        log_msg(LOG_DEFAULT, LVL_DEBUG, "call assoc->cb->recv_msg");
        assoc->cb->recv_msg(assoc->cb_arg, repp, msg);
        udp_assoc_delref(assoc);
}

/** Reset association.
 *
 * This causes any pendingreceive operations to return immediately with
 * UDP_ERESET.
 */
void udp_assoc_reset(udp_assoc_t *assoc)
{
        fibril_mutex_lock(&assoc->lock);
        assoc->reset = true;
        fibril_condvar_broadcast(&assoc->rcv_queue_cv);
        fibril_mutex_unlock(&assoc->lock);
}

static errno_t udp_assoc_queue_msg(udp_assoc_t *assoc, inet_ep2_t *epp,
    udp_msg_t *msg)
{
        udp_rcv_queue_entry_t *rqe;

        log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_queue_msg(%p, %p, %p)",
            assoc, epp, msg);

        rqe = calloc(1, sizeof(udp_rcv_queue_entry_t));
        if (rqe == NULL)
                return ENOMEM;

        link_initialize(&rqe->link);
        rqe->epp = *epp;
        rqe->msg = msg;

        fibril_mutex_lock(&assoc->lock);
        list_append(&rqe->link, &assoc->rcv_queue);
        fibril_mutex_unlock(&assoc->lock);

        fibril_condvar_broadcast(&assoc->rcv_queue_cv);

        return EOK;
}

/** Find association structure for specified endpoint pair.
 *
 * An association is uniquely identified by an endpoint pair. Look up our
 * association map and return association structure based on endpoint pair.
 * The association reference count is bumped by one.
 *
 * @param epp   Endpoint pair
 * @return      Association structure or NULL if not found.
 */
static udp_assoc_t *udp_assoc_find_ref(inet_ep2_t *epp)
{
        errno_t rc;
        void *arg;
        udp_assoc_t *assoc;

        log_msg(LOG_DEFAULT, LVL_DEBUG, "udp_assoc_find_ref(%p)", epp);
        fibril_mutex_lock(&assoc_list_lock);

        rc = amap_find_match(amap, epp, &arg);
        if (rc != EOK) {
                assert(rc == ENOENT);
                fibril_mutex_unlock(&assoc_list_lock);
                return NULL;
        }

        assoc = (udp_assoc_t *)arg;
        udp_assoc_addref(assoc);

        fibril_mutex_unlock(&assoc_list_lock);
        return assoc;
}

/**
 * @}
 */