lwdgabn.c

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/*
 * Copyright (C) 2004-2007, 2009  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: lwdgabn.c,v 1.24 2009/09/02 23:48:01 tbox Exp $ */

/*! \file */

#include <config.h>

#include <stdlib.h>

#include <isc/netaddr.h>
#include <isc/sockaddr.h>
#include <isc/socket.h>
#include <isc/string.h>         /* Required for HP/UX (and others?) */
#include <isc/util.h>

#include <dns/adb.h>
#include <dns/events.h>
#include <dns/result.h>

#include <named/types.h>
#include <named/lwaddr.h>
#include <named/lwdclient.h>
#include <named/lwresd.h>
#include <named/lwsearch.h>
#include <named/sortlist.h>

#define NEED_V4(c)      ((((c)->find_wanted & LWRES_ADDRTYPE_V4) != 0) \
                         && ((c)->v4find == NULL))
#define NEED_V6(c)      ((((c)->find_wanted & LWRES_ADDRTYPE_V6) != 0) \
                         && ((c)->v6find == NULL))

static isc_result_t start_find(ns_lwdclient_t *);
static void restart_find(ns_lwdclient_t *);
static void init_gabn(ns_lwdclient_t *);

/*%
 * Destroy any finds.  This can be used to "start over from scratch" and
 * should only be called when events are _not_ being generated by the finds.
 */
static void
cleanup_gabn(ns_lwdclient_t *client) {
        ns_lwdclient_log(50, "cleaning up client %p", client);

        if (client->v6find != NULL) {
                if (client->v6find == client->v4find)
                        client->v6find = NULL;
                else
                        dns_adb_destroyfind(&client->v6find);
        }
        if (client->v4find != NULL)
                dns_adb_destroyfind(&client->v4find);
}

static void
setup_addresses(ns_lwdclient_t *client, dns_adbfind_t *find, unsigned int at) {
        dns_adbaddrinfo_t *ai;
        lwres_addr_t *addr;
        int af;
        const struct sockaddr *sa;
        isc_result_t result;

        if (at == DNS_ADBFIND_INET)
                af = AF_INET;
        else
                af = AF_INET6;

        ai = ISC_LIST_HEAD(find->list);
        while (ai != NULL && client->gabn.naddrs < LWRES_MAX_ADDRS) {
                sa = &ai->sockaddr.type.sa;
                if (sa->sa_family != af)
                        goto next;

                addr = &client->addrs[client->gabn.naddrs];

                result = lwaddr_lwresaddr_fromsockaddr(addr, &ai->sockaddr);
                if (result != ISC_R_SUCCESS)
                        goto next;

                ns_lwdclient_log(50, "adding address %p, family %d, length %d",
                                 addr->address, addr->family, addr->length);

                client->gabn.naddrs++;
                REQUIRE(!LWRES_LINK_LINKED(addr, link));
                LWRES_LIST_APPEND(client->gabn.addrs, addr, link);

        next:
                ai = ISC_LIST_NEXT(ai, publink);
        }
}

typedef struct {
        isc_netaddr_t address;
        int rank;
} rankedaddress;

static int
addr_compare(const void *av, const void *bv) {
        const rankedaddress *a = (const rankedaddress *) av;
        const rankedaddress *b = (const rankedaddress *) bv;
        return (a->rank - b->rank);
}

static void
sort_addresses(ns_lwdclient_t *client) {
        unsigned int naddrs;
        rankedaddress *addrs;
        isc_netaddr_t remote;
        dns_addressorderfunc_t order;
        const void *arg;
        ns_lwresd_t *lwresd = client->clientmgr->listener->manager;
        unsigned int i;
        isc_result_t result;

        naddrs = client->gabn.naddrs;

        if (naddrs <= 1 || lwresd->view->sortlist == NULL)
                return;

        addrs = isc_mem_get(lwresd->mctx, sizeof(rankedaddress) * naddrs);
        if (addrs == NULL)
                return;

        isc_netaddr_fromsockaddr(&remote, &client->address);
        ns_sortlist_byaddrsetup(lwresd->view->sortlist,
                                &remote, &order, &arg);
        if (order == NULL) {
                isc_mem_put(lwresd->mctx, addrs,
                            sizeof(rankedaddress) * naddrs);
                return;
        }
        for (i = 0; i < naddrs; i++) {
                result = lwaddr_netaddr_fromlwresaddr(&addrs[i].address,
                                                      &client->addrs[i]);
                INSIST(result == ISC_R_SUCCESS);
                addrs[i].rank = (*order)(&addrs[i].address, arg);
        }
        qsort(addrs, naddrs, sizeof(rankedaddress), addr_compare);
        for (i = 0; i < naddrs; i++) {
                result = lwaddr_lwresaddr_fromnetaddr(&client->addrs[i],
                                                      &addrs[i].address);
                INSIST(result == ISC_R_SUCCESS);
        }

        isc_mem_put(lwresd->mctx, addrs, sizeof(rankedaddress) * naddrs);
}

static void
generate_reply(ns_lwdclient_t *client) {
        isc_result_t result;
        int lwres;
        isc_region_t r;
        lwres_buffer_t lwb;
        ns_lwdclientmgr_t *cm;

        cm = client->clientmgr;
        lwb.base = NULL;

        ns_lwdclient_log(50, "generating gabn reply for client %p", client);

        /*
         * We must make certain the client->find is not still active.
         * If it is either the v4 or v6 answer, just set it to NULL and
         * let the cleanup code destroy it.  Otherwise, destroy it now.
         */
        if (client->find == client->v4find || client->find == client->v6find)
                client->find = NULL;
        else
                if (client->find != NULL)
                        dns_adb_destroyfind(&client->find);

        /*
         * perhaps there are some here?
         */
        if (NEED_V6(client) && client->v4find != NULL)
                client->v6find = client->v4find;

        /*
         * Run through the finds we have and wire them up to the gabn
         * structure.
         */
        LWRES_LIST_INIT(client->gabn.addrs);
        if (client->v4find != NULL)
                setup_addresses(client, client->v4find, DNS_ADBFIND_INET);
        if (client->v6find != NULL)
                setup_addresses(client, client->v6find, DNS_ADBFIND_INET6);

        /*
         * If there are no addresses, try the next element in the search
         * path, if there are any more.  Otherwise, fall through into
         * the error handling code below.
         */
        if (client->gabn.naddrs == 0) {
                do {
                        result = ns_lwsearchctx_next(&client->searchctx);
                        if (result == ISC_R_SUCCESS) {
                                cleanup_gabn(client);
                                result = start_find(client);
                                if (result == ISC_R_SUCCESS)
                                        return;
                        }
                } while (result == ISC_R_SUCCESS);
        }

        /*
         * Render the packet.
         */
        client->pkt.recvlength = LWRES_RECVLENGTH;
        client->pkt.authtype = 0; /* XXXMLG */
        client->pkt.authlength = 0;

        /*
         * If there are no addresses, return failure.
         */
        if (client->gabn.naddrs != 0)
                client->pkt.result = LWRES_R_SUCCESS;
        else
                client->pkt.result = LWRES_R_NOTFOUND;

        sort_addresses(client);

        lwres = lwres_gabnresponse_render(cm->lwctx, &client->gabn,
                                          &client->pkt, &lwb);
        if (lwres != LWRES_R_SUCCESS)
                goto out;

        r.base = lwb.base;
        r.length = lwb.used;
        client->sendbuf = r.base;
        client->sendlength = r.length;
        result = ns_lwdclient_sendreply(client, &r);
        if (result != ISC_R_SUCCESS)
                goto out;

        NS_LWDCLIENT_SETSEND(client);

        /*
         * All done!
         */
        cleanup_gabn(client);

        return;

 out:
        cleanup_gabn(client);

        if (lwb.base != NULL)
                lwres_context_freemem(client->clientmgr->lwctx,
                                      lwb.base, lwb.length);

        ns_lwdclient_errorpktsend(client, LWRES_R_FAILURE);
}

/*
 * Take the current real name, move it to an alias slot (if any are
 * open) then put this new name in as the real name for the target.
 *
 * Return success if it can be rendered, otherwise failure.  Note that
 * not having enough alias slots open is NOT a failure.
 */
static isc_result_t
add_alias(ns_lwdclient_t *client) {
        isc_buffer_t b;
        isc_result_t result;
        isc_uint16_t naliases;

        b = client->recv_buffer;

        /*
         * Render the new name to the buffer.
         */
        result = dns_name_totext(dns_fixedname_name(&client->target_name),
                                 ISC_TRUE, &client->recv_buffer);
        if (result != ISC_R_SUCCESS)
                return (result);

        /*
         * Are there any open slots?
         */
        naliases = client->gabn.naliases;
        if (naliases < LWRES_MAX_ALIASES) {
                client->gabn.aliases[naliases] = client->gabn.realname;
                client->gabn.aliaslen[naliases] = client->gabn.realnamelen;
                client->gabn.naliases++;
        }

        /*
         * Save this name away as the current real name.
         */
        client->gabn.realname = (char *)(b.base) + b.used;
        client->gabn.realnamelen = client->recv_buffer.used - b.used;

        return (ISC_R_SUCCESS);
}

static isc_result_t
store_realname(ns_lwdclient_t *client) {
        isc_buffer_t b;
        isc_result_t result;
        dns_name_t *tname;

        b = client->recv_buffer;

        tname = dns_fixedname_name(&client->target_name);
        result = ns_lwsearchctx_current(&client->searchctx, tname);
        if (result != ISC_R_SUCCESS)
                return (result);

        /*
         * Render the new name to the buffer.
         */
        result = dns_name_totext(tname, ISC_TRUE, &client->recv_buffer);
        if (result != ISC_R_SUCCESS)
                return (result);

        /*
         * Save this name away as the current real name.
         */
        client->gabn.realname = (char *) b.base + b.used;
        client->gabn.realnamelen = client->recv_buffer.used - b.used;

        return (ISC_R_SUCCESS);
}

static void
process_gabn_finddone(isc_task_t *task, isc_event_t *ev) {
        ns_lwdclient_t *client = ev->ev_arg;
        isc_eventtype_t evtype;
        isc_boolean_t claimed;

        ns_lwdclient_log(50, "find done for task %p, client %p", task, client);

        evtype = ev->ev_type;
        isc_event_free(&ev);

        /*
         * No more info to be had?  If so, we have all the good stuff
         * right now, so we can render things.
         */
        claimed = ISC_FALSE;
        if (evtype == DNS_EVENT_ADBNOMOREADDRESSES) {
                if (NEED_V4(client)) {
                        client->v4find = client->find;
                        claimed = ISC_TRUE;
                }
                if (NEED_V6(client)) {
                        client->v6find = client->find;
                        claimed = ISC_TRUE;
                }
                if (client->find != NULL) {
                        if (claimed)
                                client->find = NULL;
                        else
                                dns_adb_destroyfind(&client->find);

                }
                generate_reply(client);
                return;
        }

        /*
         * We probably don't need this find anymore.  We're either going to
         * reissue it, or an error occurred.  Either way, we're done with
         * it.
         */
        if ((client->find != client->v4find)
            && (client->find != client->v6find)) {
                dns_adb_destroyfind(&client->find);
        } else {
                client->find = NULL;
        }

        /*
         * We have some new information we can gather.  Run off and fetch
         * it.
         */
        if (evtype == DNS_EVENT_ADBMOREADDRESSES) {
                restart_find(client);
                return;
        }

        /*
         * An error or other strangeness happened.  Drop this query.
         */
        cleanup_gabn(client);
        ns_lwdclient_errorpktsend(client, LWRES_R_FAILURE);
}

static void
restart_find(ns_lwdclient_t *client) {
        unsigned int options;
        isc_result_t result;
        isc_boolean_t claimed;

        ns_lwdclient_log(50, "starting find for client %p", client);

        /*
         * Issue a find for the name contained in the request.  We won't
         * set the bit that says "anything is good enough" -- we want it
         * all.
         */
        options = 0;
        options |= DNS_ADBFIND_WANTEVENT;
        options |= DNS_ADBFIND_RETURNLAME;

        /*
         * Set the bits up here to mark that we want this address family
         * and that we do not currently have a find pending.  We will
         * set that bit again below if it turns out we will get an event.
         */
        if (NEED_V4(client))
                options |= DNS_ADBFIND_INET;
        if (NEED_V6(client))
                options |= DNS_ADBFIND_INET6;

 find_again:
        INSIST(client->find == NULL);
        result = dns_adb_createfind(client->clientmgr->view->adb,
                                    client->clientmgr->task,
                                    process_gabn_finddone, client,
                                    dns_fixedname_name(&client->target_name),
                                    dns_rootname, 0, options, 0,
                                    dns_fixedname_name(&client->target_name),
                                    client->clientmgr->view->dstport,
                                    &client->find);

        /*
         * Did we get an alias?  If so, save it and re-issue the query.
         */
        if (result == DNS_R_ALIAS) {
                ns_lwdclient_log(50, "found alias, restarting query");
                dns_adb_destroyfind(&client->find);
                cleanup_gabn(client);
                result = add_alias(client);
                if (result != ISC_R_SUCCESS) {
                        ns_lwdclient_log(50,
                                         "out of buffer space adding alias");
                        ns_lwdclient_errorpktsend(client, LWRES_R_FAILURE);
                        return;
                }
                goto find_again;
        }

        ns_lwdclient_log(50, "find returned %d (%s)", result,
                         isc_result_totext(result));

        /*
         * Did we get an error?
         */
        if (result != ISC_R_SUCCESS) {
                if (client->find != NULL)
                        dns_adb_destroyfind(&client->find);
                cleanup_gabn(client);
                ns_lwdclient_errorpktsend(client, LWRES_R_FAILURE);
                return;
        }

        claimed = ISC_FALSE;

        /*
         * Did we get our answer to V4 addresses?
         */
        if (NEED_V4(client)
            && ((client->find->query_pending & DNS_ADBFIND_INET) == 0)) {
                ns_lwdclient_log(50, "client %p ipv4 satisfied by find %p",
                                 client, client->find);
                claimed = ISC_TRUE;
                client->v4find = client->find;
        }

        /*
         * Did we get our answer to V6 addresses?
         */
        if (NEED_V6(client)
            && ((client->find->query_pending & DNS_ADBFIND_INET6) == 0)) {
                ns_lwdclient_log(50, "client %p ipv6 satisfied by find %p",
                                 client, client->find);
                claimed = ISC_TRUE;
                client->v6find = client->find;
        }

        /*
         * If we're going to get an event, set our internal pending flag
         * and return.  When we get an event back we'll do the right
         * thing, basically by calling this function again, perhaps with a
         * new target name.
         *
         * If we have both v4 and v6, and we are still getting an event,
         * we have a programming error, so die hard.
         */
        if ((client->find->options & DNS_ADBFIND_WANTEVENT) != 0) {
                ns_lwdclient_log(50, "event will be sent");
                INSIST(client->v4find == NULL || client->v6find == NULL);
                return;
        }
        ns_lwdclient_log(50, "no event will be sent");
        if (claimed)
                client->find = NULL;
        else
                dns_adb_destroyfind(&client->find);

        /*
         * We seem to have everything we asked for, or at least we are
         * able to respond with things we've learned.
         */

        generate_reply(client);
}

static isc_result_t
start_find(ns_lwdclient_t *client) {
        isc_result_t result;

        /*
         * Initialize the real name and alias arrays in the reply we're
         * going to build up.
         */
        init_gabn(client);

        result = store_realname(client);
        if (result != ISC_R_SUCCESS)
                return (result);
        restart_find(client);
        return (ISC_R_SUCCESS);

}

static void
init_gabn(ns_lwdclient_t *client) {
        int i;

        /*
         * Initialize the real name and alias arrays in the reply we're
         * going to build up.
         */
        for (i = 0; i < LWRES_MAX_ALIASES; i++) {
                client->aliases[i] = NULL;
                client->aliaslen[i] = 0;
        }
        for (i = 0; i < LWRES_MAX_ADDRS; i++) {
                client->addrs[i].family = 0;
                client->addrs[i].length = 0;
                memset(client->addrs[i].address, 0, LWRES_ADDR_MAXLEN);
                LWRES_LINK_INIT(&client->addrs[i], link);
        }

        client->gabn.naliases = 0;
        client->gabn.naddrs = 0;
        client->gabn.realname = NULL;
        client->gabn.aliases = client->aliases;
        client->gabn.realnamelen = 0;
        client->gabn.aliaslen = client->aliaslen;
        LWRES_LIST_INIT(client->gabn.addrs);
        client->gabn.base = NULL;
        client->gabn.baselen = 0;

        /*
         * Set up the internal buffer to point to the receive region.
         */
        isc_buffer_init(&client->recv_buffer, client->buffer, LWRES_RECVLENGTH);
}

/*
 * When we are called, we can be assured that:
 *
 *      client->sockaddr contains the address we need to reply to,
 *
 *      client->pkt contains the packet header data,
 *
 *      the packet "checks out" overall -- any MD5 hashes or crypto
 *      bits have been verified,
 *
 *      "b" points to the remaining data after the packet header
 *      was parsed off.
 *
 *      We are in a the RECVDONE state.
 *
 * From this state we will enter the SEND state if we happen to have
 * everything we need or we need to return an error packet, or to the
 * FINDWAIT state if we need to look things up.
 */
void
ns_lwdclient_processgabn(ns_lwdclient_t *client, lwres_buffer_t *b) {
        isc_result_t result;
        lwres_gabnrequest_t *req;
        ns_lwdclientmgr_t *cm;
        isc_buffer_t namebuf;

        REQUIRE(NS_LWDCLIENT_ISRECVDONE(client));

        cm = client->clientmgr;
        req = NULL;

        result = lwres_gabnrequest_parse(client->clientmgr->lwctx,
                                         b, &client->pkt, &req);
        if (result != LWRES_R_SUCCESS)
                goto out;
        if (req->name == NULL)
                goto out;

        isc_buffer_init(&namebuf, req->name, req->namelen);
        isc_buffer_add(&namebuf, req->namelen);

        dns_fixedname_init(&client->target_name);
        dns_fixedname_init(&client->query_name);
        result = dns_name_fromtext(dns_fixedname_name(&client->query_name),
                                   &namebuf, NULL, 0, NULL);
        if (result != ISC_R_SUCCESS)
                goto out;
        ns_lwsearchctx_init(&client->searchctx,
                            cm->listener->manager->search,
                            dns_fixedname_name(&client->query_name),
                            cm->listener->manager->ndots);
        ns_lwsearchctx_first(&client->searchctx);

        client->find_wanted = req->addrtypes;
        ns_lwdclient_log(50, "client %p looking for addrtypes %08x",
                         client, client->find_wanted);

        /*
         * We no longer need to keep this around.
         */
        lwres_gabnrequest_free(client->clientmgr->lwctx, &req);

        /*
         * Start the find.
         */
        result = start_find(client);
        if (result != ISC_R_SUCCESS)
                goto out;

        return;

        /*
         * We're screwed.  Return an error packet to our caller.
         */
 out:
        if (req != NULL)
                lwres_gabnrequest_free(client->clientmgr->lwctx, &req);

        ns_lwdclient_errorpktsend(client, LWRES_R_FAILURE);
}

---