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/* Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <urcu.h>
#include "contrib/mempattern.h"
#include "contrib/sockaddr.h"
#include "knot/nameserver/axfr.h"
#include "knot/nameserver/internet.h"
#include "knot/nameserver/log.h"
#include "knot/nameserver/xfr.h"
#include "libknot/libknot.h"
#define ZONE_NAME(qdata) knot_pkt_qname((qdata)->query)
#define REMOTE(qdata) (struct sockaddr *)knotd_qdata_remote_addr(qdata)
#define AXFROUT_LOG(priority, qdata, fmt...) \
ns_log(priority, ZONE_NAME(qdata), LOG_OPERATION_AXFR, \
LOG_DIRECTION_OUT, REMOTE(qdata), false, fmt)
/* AXFR context. @note aliasing the generic xfr_proc */
struct axfr_proc {
struct xfr_proc proc;
trie_it_t *i;
zone_tree_it_t it;
unsigned cur_rrset;
};
static int axfr_put_rrsets(knot_pkt_t *pkt, zone_node_t *node,
struct axfr_proc *state)
{
assert(node != NULL);
/* Append all RRs. */
for (unsigned i = state->cur_rrset; i < node->rrset_count; ++i) {
knot_rrset_t rrset = node_rrset_at(node, i);
if (rrset.type == KNOT_RRTYPE_SOA) {
continue;
}
int ret = knot_pkt_put(pkt, 0, &rrset, KNOT_PF_NOTRUNC | KNOT_PF_ORIGTTL);
if (ret != KNOT_EOK) {
/* If something failed, remember the current RR for later. */
state->cur_rrset = i;
return ret;
}
if (pkt->size > KNOT_WIRE_PTR_MAX) {
// optimization: once the XFR DNS message is > 16 KiB, compression
// is limited. Better wrap to next message.
state->cur_rrset = i + 1;
return KNOT_ESPACE;
}
}
state->cur_rrset = 0;
return KNOT_EOK;
}
static int axfr_process_node_tree(knot_pkt_t *pkt, const void *item,
struct xfr_proc *state)
{
assert(item != NULL);
struct axfr_proc *axfr = (struct axfr_proc*)state;
int ret = zone_tree_it_begin((zone_tree_t *)item, &axfr->it); // does nothing if already iterating
/* Put responses. */
while (ret == KNOT_EOK && !zone_tree_it_finished(&axfr->it)) {
zone_node_t *node = zone_tree_it_val(&axfr->it);
ret = axfr_put_rrsets(pkt, node, axfr);
if (ret == KNOT_EOK) {
zone_tree_it_next(&axfr->it);
}
}
/* Finished all nodes. */
if (ret == KNOT_EOK) {
zone_tree_it_free(&axfr->it);
}
return ret;
}
static void axfr_query_cleanup(knotd_qdata_t *qdata)
{
struct axfr_proc *axfr = (struct axfr_proc *)qdata->extra->ext;
zone_tree_it_free(&axfr->it);
ptrlist_free(&axfr->proc.nodes, qdata->mm);
mm_free(qdata->mm, axfr);
/* Allow zone changes (finished). */
rcu_read_unlock();
}
static int axfr_query_check(knotd_qdata_t *qdata)
{
NS_NEED_ZONE(qdata, KNOT_RCODE_NOTAUTH);
NS_NEED_AUTH(qdata, ACL_ACTION_TRANSFER);
NS_NEED_ZONE_CONTENTS(qdata);
return KNOT_STATE_DONE;
}
static int axfr_query_init(knotd_qdata_t *qdata)
{
assert(qdata);
/* Check AXFR query validity. */
if (axfr_query_check(qdata) == KNOT_STATE_FAIL) {
if (qdata->rcode == KNOT_RCODE_FORMERR) {
return KNOT_EMALF;
} else {
return KNOT_EDENIED;
}
}
if (zone_get_flag(qdata->extra->zone, ZONE_XFR_FROZEN, false)) {
qdata->rcode = KNOT_RCODE_REFUSED;
qdata->rcode_ede = KNOT_EDNS_EDE_NOT_READY;
return KNOT_EAGAIN;
}
/* Create transfer processing context. */
knot_mm_t *mm = qdata->mm;
struct axfr_proc *axfr = mm_alloc(mm, sizeof(struct axfr_proc));
if (axfr == NULL) {
return KNOT_ENOMEM;
}
memset(axfr, 0, sizeof(struct axfr_proc));
init_list(&axfr->proc.nodes);
/* Put data to process. */
xfr_stats_begin(&axfr->proc.stats);
const zone_contents_t *contents = qdata->extra->contents;
/* Must be non-NULL for the first message. */
assert(contents);
ptrlist_add(&axfr->proc.nodes, contents->nodes, mm);
/* Put NSEC3 data if exists. */
if (!zone_tree_is_empty(contents->nsec3_nodes)) {
ptrlist_add(&axfr->proc.nodes, contents->nsec3_nodes, mm);
}
/* Set up cleanup callback. */
qdata->extra->ext = axfr;
qdata->extra->ext_cleanup = &axfr_query_cleanup;
/* No zone changes during multipacket answer (unlocked in axfr_answer_cleanup) */
rcu_read_lock();
return KNOT_EOK;
}
int axfr_process_query(knot_pkt_t *pkt, knotd_qdata_t *qdata)
{
if (pkt == NULL || qdata == NULL) {
return KNOT_STATE_FAIL;
}
/* AXFR over UDP isn't allowed, respond with NOTIMPL. */
if (qdata->params->proto == KNOTD_QUERY_PROTO_UDP) {
qdata->rcode = KNOT_RCODE_NOTIMPL;
return KNOT_STATE_FAIL;
}
/* Initialize on first call. */
struct axfr_proc *axfr = qdata->extra->ext;
if (axfr == NULL) {
int ret = axfr_query_init(qdata);
axfr = qdata->extra->ext;
switch (ret) {
case KNOT_EOK: /* OK */
AXFROUT_LOG(LOG_INFO, qdata, "started, serial %u",
zone_contents_serial(qdata->extra->contents));
break;
case KNOT_EDENIED: /* Not authorized, already logged. */
return KNOT_STATE_FAIL;
case KNOT_EMALF: /* Malformed query. */
AXFROUT_LOG(LOG_DEBUG, qdata, "malformed query");
return KNOT_STATE_FAIL;
case KNOT_EAGAIN: /* Outgoing AXFR temporarily disabled. */
AXFROUT_LOG(LOG_INFO, qdata, "outgoing AXFR frozen");
return KNOT_STATE_FAIL;
default:
AXFROUT_LOG(LOG_ERR, qdata, "failed to start (%s)",
knot_strerror(ret));
return KNOT_STATE_FAIL;
}
}
/* Reserve space for TSIG. */
int ret = knot_pkt_reserve(pkt, knot_tsig_wire_size(&qdata->sign.tsig_key));
if (ret != KNOT_EOK) {
return KNOT_STATE_FAIL;
}
/* Answer current packet (or continue). */
ret = xfr_process_list(pkt, &axfr_process_node_tree, qdata);
switch (ret) {
case KNOT_ESPACE: /* Couldn't write more, send packet and continue. */
return KNOT_STATE_PRODUCE; /* Check for more. */
case KNOT_EOK: /* Last response. */
xfr_stats_end(&axfr->proc.stats);
xfr_log_finished(ZONE_NAME(qdata), LOG_OPERATION_AXFR, LOG_DIRECTION_OUT,
REMOTE(qdata), false, &axfr->proc.stats);
return KNOT_STATE_DONE;
default: /* Generic error. */
AXFROUT_LOG(LOG_ERR, qdata, "failed (%s)", knot_strerror(ret));
return KNOT_STATE_FAIL;
}
}
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