bin/named/lwdclient.c

/*
 * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2000, 2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: lwdclient.c,v 1.22 2007/06/18 23:47:18 tbox Exp $ */

/*! \file */

#include <config.h>

#include <isc/socket.h>
#include <isc/string.h>
#include <isc/task.h>
#include <isc/util.h>

#include <dns/adb.h>
#include <dns/view.h>
#include <dns/log.h>

#include <named/types.h>
#include <named/log.h>
#include <named/lwresd.h>
#include <named/lwdclient.h>

#define SHUTTINGDOWN(cm) ((cm->flags & NS_LWDCLIENTMGR_FLAGSHUTTINGDOWN) != 0)

static void
lwdclientmgr_shutdown_callback(isc_task_t *task, isc_event_t *ev);

void
ns_lwdclient_log(int level, const char *format, ...) {
    va_list args;

    va_start(args, format);
    isc_log_vwrite(dns_lctx,
               DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_ADB,
               ISC_LOG_DEBUG(level), format, args);
    va_end(args);
}

isc_result_t
ns_lwdclientmgr_create(ns_lwreslistener_t *listener, unsigned int nclients,
            isc_taskmgr_t *taskmgr)
{
    ns_lwresd_t *lwresd = listener->manager;
    ns_lwdclientmgr_t *cm;
    ns_lwdclient_t *client;
    unsigned int i;
    isc_result_t result = ISC_R_FAILURE;

    cm = isc_mem_get(lwresd->mctx, sizeof(ns_lwdclientmgr_t));
    if (cm == NULL)
        return (ISC_R_NOMEMORY);

    cm->listener = NULL;
    ns_lwreslistener_attach(listener, &cm->listener);
    cm->mctx = lwresd->mctx;
    cm->sock = NULL;
    isc_socket_attach(listener->sock, &cm->sock);
    cm->view = lwresd->view;
    cm->lwctx = NULL;
    cm->task = NULL;
    cm->flags = 0;
    ISC_LINK_INIT(cm, link);
    ISC_LIST_INIT(cm->idle);
    ISC_LIST_INIT(cm->running);

    if (lwres_context_create(&cm->lwctx, cm->mctx,
                 ns__lwresd_memalloc, ns__lwresd_memfree,
                 LWRES_CONTEXT_SERVERMODE)
        != ISC_R_SUCCESS)
        goto errout;

    for (i = 0; i < nclients; i++) {
        client = isc_mem_get(lwresd->mctx, sizeof(ns_lwdclient_t));
        if (client != NULL) {
            ns_lwdclient_log(50, "created client %p, manager %p",
                     client, cm);
            ns_lwdclient_initialize(client, cm);
        }
    }

    /*
     * If we could create no clients, clean up and return.
     */
    if (ISC_LIST_EMPTY(cm->idle))
        goto errout;

    result = isc_task_create(taskmgr, 0, &cm->task);
    if (result != ISC_R_SUCCESS)
        goto errout;
    isc_task_setname(cm->task, "lwdclient", NULL);

    /*
     * This MUST be last, since there is no way to cancel an onshutdown...
     */
    result = isc_task_onshutdown(cm->task, lwdclientmgr_shutdown_callback,
                     cm);
    if (result != ISC_R_SUCCESS)
        goto errout;

    ns_lwreslistener_linkcm(listener, cm);

    return (ISC_R_SUCCESS);

 errout:
    client = ISC_LIST_HEAD(cm->idle);
    while (client != NULL) {
        ISC_LIST_UNLINK(cm->idle, client, link);
        isc_mem_put(lwresd->mctx, client, sizeof(*client));
        client = ISC_LIST_HEAD(cm->idle);
    }

    if (cm->task != NULL)
        isc_task_detach(&cm->task);

    if (cm->lwctx != NULL)
        lwres_context_destroy(&cm->lwctx);

    isc_mem_put(lwresd->mctx, cm, sizeof(*cm));
    return (result);
}

static void
lwdclientmgr_destroy(ns_lwdclientmgr_t *cm) {
    ns_lwdclient_t *client;
    ns_lwreslistener_t *listener;

    if (!SHUTTINGDOWN(cm))
        return;

    /*
     * run through the idle list and free the clients there.  Idle
     * clients do not have a recv running nor do they have any finds
     * or similar running.
     */
    client = ISC_LIST_HEAD(cm->idle);
    while (client != NULL) {
        ns_lwdclient_log(50, "destroying client %p, manager %p",
                 client, cm);
        ISC_LIST_UNLINK(cm->idle, client, link);
        isc_mem_put(cm->mctx, client, sizeof(*client));
        client = ISC_LIST_HEAD(cm->idle);
    }

    if (!ISC_LIST_EMPTY(cm->running))
        return;

    lwres_context_destroy(&cm->lwctx);
    cm->view = NULL;
    isc_socket_detach(&cm->sock);
    isc_task_detach(&cm->task);

    listener = cm->listener;
    ns_lwreslistener_unlinkcm(listener, cm);
    ns_lwdclient_log(50, "destroying manager %p", cm);
    isc_mem_put(cm->mctx, cm, sizeof(*cm));
    ns_lwreslistener_detach(&listener);
}

static void
process_request(ns_lwdclient_t *client) {
    lwres_buffer_t b;
    isc_result_t result;

    lwres_buffer_init(&b, client->buffer, client->recvlength);
    lwres_buffer_add(&b, client->recvlength);

    result = lwres_lwpacket_parseheader(&b, &client->pkt);
    if (result != ISC_R_SUCCESS) {
        ns_lwdclient_log(50, "invalid packet header received");
        goto restart;
    }

    ns_lwdclient_log(50, "opcode %08x", client->pkt.opcode);

    switch (client->pkt.opcode) {
    case LWRES_OPCODE_GETADDRSBYNAME:
        ns_lwdclient_processgabn(client, &b);
        return;
    case LWRES_OPCODE_GETNAMEBYADDR:
        ns_lwdclient_processgnba(client, &b);
        return;
    case LWRES_OPCODE_GETRDATABYNAME:
        ns_lwdclient_processgrbn(client, &b);
        return;
    case LWRES_OPCODE_NOOP:
        ns_lwdclient_processnoop(client, &b);
        return;
    default:
        ns_lwdclient_log(50, "unknown opcode %08x", client->pkt.opcode);
        goto restart;
    }

    /*
     * Drop the packet.
     */
 restart:
    ns_lwdclient_log(50, "restarting client %p...", client);
    ns_lwdclient_stateidle(client);
}

void
ns_lwdclient_recv(isc_task_t *task, isc_event_t *ev) {
    isc_result_t result;
    ns_lwdclient_t *client = ev->ev_arg;
    ns_lwdclientmgr_t *cm = client->clientmgr;
    isc_socketevent_t *dev = (isc_socketevent_t *)ev;

    INSIST(dev->region.base == client->buffer);
    INSIST(NS_LWDCLIENT_ISRECV(client));

    NS_LWDCLIENT_SETRECVDONE(client);

    INSIST((cm->flags & NS_LWDCLIENTMGR_FLAGRECVPENDING) != 0);
    cm->flags &= ~NS_LWDCLIENTMGR_FLAGRECVPENDING;

    ns_lwdclient_log(50,
             "event received: task %p, length %u, result %u (%s)",
             task, dev->n, dev->result,
             isc_result_totext(dev->result));

    if (dev->result != ISC_R_SUCCESS) {
        isc_event_free(&ev);
        dev = NULL;

        /*
         * Go idle.
         */
        ns_lwdclient_stateidle(client);

        return;
    }

    client->recvlength = dev->n;
    client->address = dev->address;
    if ((dev->attributes & ISC_SOCKEVENTATTR_PKTINFO) != 0) {
        client->pktinfo = dev->pktinfo;
        client->pktinfo_valid = ISC_TRUE;
    } else
        client->pktinfo_valid = ISC_FALSE;
    isc_event_free(&ev);
    dev = NULL;

    result = ns_lwdclient_startrecv(cm);
    if (result != ISC_R_SUCCESS)
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_LWRESD, ISC_LOG_ERROR,
                  "could not start lwres "
                  "client handler: %s",
                  isc_result_totext(result));

    process_request(client);
}

/*
 * This function will start a new recv() on a socket for this client manager.
 */
isc_result_t
ns_lwdclient_startrecv(ns_lwdclientmgr_t *cm) {
    ns_lwdclient_t *client;
    isc_result_t result;
    isc_region_t r;

    if (SHUTTINGDOWN(cm)) {
        lwdclientmgr_destroy(cm);
        return (ISC_R_SUCCESS);
    }

    /*
     * If a recv is already running, don't bother.
     */
    if ((cm->flags & NS_LWDCLIENTMGR_FLAGRECVPENDING) != 0)
        return (ISC_R_SUCCESS);

    /*
     * If we have no idle slots, just return success.
     */
    client = ISC_LIST_HEAD(cm->idle);
    if (client == NULL)
        return (ISC_R_SUCCESS);
    INSIST(NS_LWDCLIENT_ISIDLE(client));

    /*
     * Issue the recv.  If it fails, return that it did.
     */
    r.base = client->buffer;
    r.length = LWRES_RECVLENGTH;
    result = isc_socket_recv(cm->sock, &r, 0, cm->task, ns_lwdclient_recv,
                 client);
    if (result != ISC_R_SUCCESS)
        return (result);

    /*
     * Set the flag to say we've issued a recv() call.
     */
    cm->flags |= NS_LWDCLIENTMGR_FLAGRECVPENDING;

    /*
     * Remove the client from the idle list, and put it on the running
     * list.
     */
    NS_LWDCLIENT_SETRECV(client);
    ISC_LIST_UNLINK(cm->idle, client, link);
    ISC_LIST_APPEND(cm->running, client, link);

    return (ISC_R_SUCCESS);
}

static void
lwdclientmgr_shutdown_callback(isc_task_t *task, isc_event_t *ev) {
    ns_lwdclientmgr_t *cm = ev->ev_arg;
    ns_lwdclient_t *client;

    REQUIRE(!SHUTTINGDOWN(cm));

    ns_lwdclient_log(50, "got shutdown event, task %p, lwdclientmgr %p",
             task, cm);

    /*
     * run through the idle list and free the clients there.  Idle
     * clients do not have a recv running nor do they have any finds
     * or similar running.
     */
    client = ISC_LIST_HEAD(cm->idle);
    while (client != NULL) {
        ns_lwdclient_log(50, "destroying client %p, manager %p",
                 client, cm);
        ISC_LIST_UNLINK(cm->idle, client, link);
        isc_mem_put(cm->mctx, client, sizeof(*client));
        client = ISC_LIST_HEAD(cm->idle);
    }

    /*
     * Cancel any pending I/O.
     */
    isc_socket_cancel(cm->sock, task, ISC_SOCKCANCEL_ALL);

    /*
     * Run through the running client list and kill off any finds
     * in progress.
     */
    client = ISC_LIST_HEAD(cm->running);
    while (client != NULL) {
        if (client->find != client->v4find
            && client->find != client->v6find)
            dns_adb_cancelfind(client->find);
        if (client->v4find != NULL)
            dns_adb_cancelfind(client->v4find);
        if (client->v6find != NULL)
            dns_adb_cancelfind(client->v6find);
        client = ISC_LIST_NEXT(client, link);
    }

    cm->flags |= NS_LWDCLIENTMGR_FLAGSHUTTINGDOWN;

    isc_event_free(&ev);
}

/*
 * Do all the crap needed to move a client from the run queue to the idle
 * queue.
 */
void
ns_lwdclient_stateidle(ns_lwdclient_t *client) {
    ns_lwdclientmgr_t *cm;
    isc_result_t result;

    cm = client->clientmgr;

    INSIST(client->sendbuf == NULL);
    INSIST(client->sendlength == 0);
    INSIST(client->arg == NULL);
    INSIST(client->v4find == NULL);
    INSIST(client->v6find == NULL);

    ISC_LIST_UNLINK(cm->running, client, link);
    ISC_LIST_PREPEND(cm->idle, client, link);

    NS_LWDCLIENT_SETIDLE(client);

    result = ns_lwdclient_startrecv(cm);
    if (result != ISC_R_SUCCESS)
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_LWRESD, ISC_LOG_ERROR,
                  "could not start lwres "
                  "client handler: %s",
                  isc_result_totext(result));
}

void
ns_lwdclient_send(isc_task_t *task, isc_event_t *ev) {
    ns_lwdclient_t *client = ev->ev_arg;
    ns_lwdclientmgr_t *cm = client->clientmgr;
    isc_socketevent_t *dev = (isc_socketevent_t *)ev;

    UNUSED(task);
    UNUSED(dev);

    INSIST(NS_LWDCLIENT_ISSEND(client));
    INSIST(client->sendbuf == dev->region.base);

    ns_lwdclient_log(50, "task %p for client %p got send-done event",
             task, client);

    if (client->sendbuf != client->buffer)
        lwres_context_freemem(cm->lwctx, client->sendbuf,
                      client->sendlength);
    client->sendbuf = NULL;
    client->sendlength = 0;

    ns_lwdclient_stateidle(client);

    isc_event_free(&ev);
}

isc_result_t
ns_lwdclient_sendreply(ns_lwdclient_t *client, isc_region_t *r) {
    struct in6_pktinfo *pktinfo;
    ns_lwdclientmgr_t *cm = client->clientmgr;

    if (client->pktinfo_valid)
        pktinfo = &client->pktinfo;
    else
        pktinfo = NULL;
    return (isc_socket_sendto(cm->sock, r, cm->task, ns_lwdclient_send,
                  client, &client->address, pktinfo));
}

void
ns_lwdclient_initialize(ns_lwdclient_t *client, ns_lwdclientmgr_t *cmgr) {
    client->clientmgr = cmgr;
    ISC_LINK_INIT(client, link);
    NS_LWDCLIENT_SETIDLE(client);
    client->arg = NULL;

    client->recvlength = 0;

    client->sendbuf = NULL;
    client->sendlength = 0;

    client->find = NULL;
    client->v4find = NULL;
    client->v6find = NULL;
    client->find_wanted = 0;

    client->options = 0;
    client->byaddr = NULL;

    client->lookup = NULL;

    client->pktinfo_valid = ISC_FALSE;

    ISC_LIST_APPEND(cmgr->idle, client, link);
}