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Provide thread safe access to dns_xfrin_t state

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dns_xfrin_t state may be accessed from different threads when
when reporting transfer state.  Ensure access is thread safe by
using atomics and locks where appropriate.
This commit is contained in:
Mark Andrews 2023-07-06 14:00:48 +10:00 committed by Aram Sargsyan
parent 42f41f003e
commit bed4e36c86
2 changed files with 57 additions and 33 deletions
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4
lib/dns/include/dns/xfrin.h
View file

@ -125,8 +125,8 @@ dns_xfrin_getendserial(const dns_xfrin_t *xfr);
*/
void
dns_xfrin_getstats(const dns_xfrin_t *xfr, unsigned int *nmsgp,
unsigned int *nrecsp, uint64_t *nbytesp);
dns_xfrin_getstats(dns_xfrin_t *xfr, unsigned int *nmsgp, unsigned int *nrecsp,
uint64_t *nbytesp);
/*%<
* Get various statistics values of the xfrin object: number of the received
* messages, number of the received records, number of the received bytes.

86
lib/dns/xfrin.c
View file

@ -16,6 +16,7 @@
#include <inttypes.h>
#include <stdbool.h>
#include <isc/atomic.h>
#include <isc/mem.h>
#include <isc/random.h>
#include <isc/result.h>
@ -140,11 +141,14 @@ struct dns_xfrin {
dns_diff_t diff; /*%< Pending database changes */
int difflen; /*%< Number of pending tuples */
xfrin_state_t state;
_Atomic xfrin_state_t state;
uint32_t end_serial;
uint32_t expireopt;
bool edns, is_ixfr, expireoptset;
bool edns, expireoptset;
atomic_bool is_ixfr;
isc_mutex_t statslock;
/* Locked by statslock. */
unsigned int nmsg; /*%< Number of messages recvd */
unsigned int nrecs; /*%< Number of records recvd */
uint64_t nbytes; /*%< Number of bytes received */
@ -269,7 +273,7 @@ static isc_result_t
axfr_init(dns_xfrin_t *xfr) {
isc_result_t result;
xfr->is_ixfr = false;
atomic_store(&xfr->is_ixfr, false);
if (xfr->db != NULL) {
dns_db_detach(&xfr->db);
@ -385,7 +389,7 @@ ixfr_init(dns_xfrin_t *xfr) {
return (DNS_R_FORMERR);
}
xfr->is_ixfr = true;
atomic_store(&xfr->is_ixfr, true);
INSIST(xfr->db != NULL);
xfr->difflen = 0;
@ -491,7 +495,9 @@ static isc_result_t
xfr_rr(dns_xfrin_t *xfr, dns_name_t *name, uint32_t ttl, dns_rdata_t *rdata) {
isc_result_t result;
LOCK(&xfr->statslock);
xfr->nrecs++;
UNLOCK(&xfr->statslock);
if (rdata->type == dns_rdatatype_none ||
dns_rdatatype_ismeta(rdata->type))
@ -519,7 +525,7 @@ xfr_rr(dns_xfrin_t *xfr, dns_name_t *name, uint32_t ttl, dns_rdata_t *rdata) {
}
redo:
switch (xfr->state) {
switch (atomic_load(&xfr->state)) {
case XFRST_SOAQUERY:
if (rdata->type != dns_rdatatype_soa) {
xfrin_log(xfr, ISC_LOG_NOTICE,
@ -536,7 +542,7 @@ redo:
xfr->ixfr.request_serial, xfr->end_serial);
FAIL(DNS_R_UPTODATE);
}
xfr->state = XFRST_GOTSOA;
atomic_store(&xfr->state, XFRST_GOTSOA);
break;
case XFRST_GOTSOA:
@ -578,7 +584,7 @@ redo:
xfr->firstsoa_data = isc_mem_allocate(xfr->mctx, rdata->length);
memcpy(xfr->firstsoa_data, rdata->data, rdata->length);
xfr->firstsoa.data = xfr->firstsoa_data;
xfr->state = XFRST_FIRSTDATA;
atomic_store(&xfr->state, XFRST_FIRSTDATA);
break;
case XFRST_FIRSTDATA:
@ -593,25 +599,25 @@ redo:
xfrin_log(xfr, ISC_LOG_DEBUG(3),
"got incremental response");
CHECK(ixfr_init(xfr));
xfr->state = XFRST_IXFR_DELSOA;
atomic_store(&xfr->state, XFRST_IXFR_DELSOA);
} else {
xfrin_log(xfr, ISC_LOG_DEBUG(3),
"got nonincremental response");
CHECK(axfr_init(xfr));
xfr->state = XFRST_AXFR;
atomic_store(&xfr->state, XFRST_AXFR);
}
goto redo;
case XFRST_IXFR_DELSOA:
INSIST(rdata->type == dns_rdatatype_soa);
CHECK(ixfr_putdata(xfr, DNS_DIFFOP_DEL, name, ttl, rdata));
xfr->state = XFRST_IXFR_DEL;
atomic_store(&xfr->state, XFRST_IXFR_DEL);
break;
case XFRST_IXFR_DEL:
if (rdata->type == dns_rdatatype_soa) {
uint32_t soa_serial = dns_soa_getserial(rdata);
xfr->state = XFRST_IXFR_ADDSOA;
atomic_store(&xfr->state, XFRST_IXFR_ADDSOA);
xfr->ixfr.current_serial = soa_serial;
goto redo;
}
@ -621,7 +627,7 @@ redo:
case XFRST_IXFR_ADDSOA:
INSIST(rdata->type == dns_rdatatype_soa);
CHECK(ixfr_putdata(xfr, DNS_DIFFOP_ADD, name, ttl, rdata));
xfr->state = XFRST_IXFR_ADD;
atomic_store(&xfr->state, XFRST_IXFR_ADD);
break;
case XFRST_IXFR_ADD:
@ -629,7 +635,7 @@ redo:
uint32_t soa_serial = dns_soa_getserial(rdata);
if (soa_serial == xfr->end_serial) {
CHECK(ixfr_commit(xfr));
xfr->state = XFRST_IXFR_END;
atomic_store(&xfr->state, XFRST_IXFR_END);
break;
} else if (soa_serial != xfr->ixfr.current_serial) {
xfrin_log(xfr, ISC_LOG_NOTICE,
@ -639,7 +645,7 @@ redo:
FAIL(DNS_R_FORMERR);
} else {
CHECK(ixfr_commit(xfr));
xfr->state = XFRST_IXFR_DELSOA;
atomic_store(&xfr->state, XFRST_IXFR_DELSOA);
goto redo;
}
}
@ -674,7 +680,7 @@ redo:
FAIL(DNS_R_FORMERR);
}
CHECK(axfr_commit(xfr));
xfr->state = XFRST_AXFR_END;
atomic_store(&xfr->state, XFRST_AXFR_END);
break;
}
break;
@ -778,10 +784,10 @@ dns_xfrin_getstate(const dns_xfrin_t *xfr, const char **statestr,
REQUIRE(statestr != NULL && *statestr == NULL);
REQUIRE(is_ixfr != NULL);
state = xfr->state;
state = atomic_load(&xfr->state);
*statestr = "";
*is_first_data_received = (state > XFRST_FIRSTDATA);
*is_ixfr = xfr->is_ixfr;
*is_ixfr = atomic_load(&xfr->is_ixfr);
switch (state) {
case XFRST_SOAQUERY:
@ -822,14 +828,16 @@ dns_xfrin_getendserial(const dns_xfrin_t *xfr) {
}
void
dns_xfrin_getstats(const dns_xfrin_t *xfr, unsigned int *nmsgp,
unsigned int *nrecsp, uint64_t *nbytesp) {
dns_xfrin_getstats(dns_xfrin_t *xfr, unsigned int *nmsgp, unsigned int *nrecsp,
uint64_t *nbytesp) {
REQUIRE(VALID_XFRIN(xfr));
REQUIRE(nmsgp != NULL && nrecsp != NULL && nbytesp != NULL);
LOCK(&xfr->statslock);
*nmsgp = xfr->nmsg;
*nrecsp = xfr->nrecs;
*nbytesp = xfr->nbytes;
UNLOCK(&xfr->statslock);
}
const isc_sockaddr_t *
@ -925,7 +933,7 @@ xfrin_fail(dns_xfrin_t *xfr, isc_result_t result, const char *msg) {
{
xfrin_log(xfr, ISC_LOG_ERROR, "%s: %s", msg,
isc_result_totext(result));
if (xfr->is_ixfr) {
if (atomic_load(&xfr->is_ixfr)) {
/*
* Pass special result code to force AXFR retry
*/
@ -979,7 +987,10 @@ xfrin_create(isc_mem_t *mctx, dns_zone_t *zone, dns_db_t *db,
dns_view_weakattach(dns_zone_getview(zone), &xfr->view);
dns_name_init(&xfr->name, NULL);
isc_mutex_init(&xfr->statslock);
atomic_init(&xfr->shuttingdown, false);
atomic_init(&xfr->is_ixfr, false);
if (db != NULL) {
dns_db_attach(db, &xfr->db);
@ -988,9 +999,9 @@ xfrin_create(isc_mem_t *mctx, dns_zone_t *zone, dns_db_t *db,
dns_diff_init(xfr->mctx, &xfr->diff);
if (reqtype == dns_rdatatype_soa) {
xfr->state = XFRST_SOAQUERY;
atomic_init(&xfr->state, XFRST_SOAQUERY);
} else {
xfr->state = XFRST_INITIALSOA;
atomic_init(&xfr->state, XFRST_INITIALSOA);
}
xfr->start = isc_time_now();
@ -1363,9 +1374,11 @@ xfrin_send_request(dns_xfrin_t *xfr) {
CHECK(add_opt(msg, udpsize, reqnsid, reqexpire));
}
LOCK(&xfr->statslock);
xfr->nmsg = 0;
xfr->nrecs = 0;
xfr->nbytes = 0;
UNLOCK(&xfr->statslock);
xfr->start = isc_time_now();
msg->id = xfr->id;
if (xfr->tsigctx != NULL) {
@ -1497,9 +1510,11 @@ xfrin_recv_done(isc_result_t result, isc_region_t *region, void *arg) {
dns_message_setclass(msg, xfr->rdclass);
LOCK(&xfr->statslock);
if (xfr->nmsg > 0) {
msg->tcp_continuation = 1;
}
UNLOCK(&xfr->statslock);
isc_buffer_init(&buffer, region->base, region->length);
isc_buffer_add(&buffer, region->length);
@ -1523,8 +1538,8 @@ xfrin_recv_done(isc_result_t result, isc_region_t *region, void *arg) {
{
if (result == ISC_R_SUCCESS &&
msg->rcode == dns_rcode_formerr && xfr->edns &&
(xfr->state == XFRST_SOAQUERY ||
xfr->state == XFRST_INITIALSOA))
(atomic_load(&xfr->state) == XFRST_SOAQUERY ||
atomic_load(&xfr->state) == XFRST_INITIALSOA))
{
xfr->edns = false;
dns_message_detach(&msg);
@ -1559,7 +1574,7 @@ xfrin_recv_done(isc_result_t result, isc_region_t *region, void *arg) {
dns_message_detach(&msg);
xfrin_reset(xfr);
xfr->reqtype = dns_rdatatype_soa;
xfr->state = XFRST_SOAQUERY;
atomic_store(&xfr->state, XFRST_SOAQUERY);
try_again:
result = xfrin_start(xfr);
if (result != ISC_R_SUCCESS) {
@ -1583,7 +1598,8 @@ xfrin_recv_done(isc_result_t result, isc_region_t *region, void *arg) {
goto failure;
}
if ((xfr->state == XFRST_SOAQUERY || xfr->state == XFRST_INITIALSOA) &&
if ((atomic_load(&xfr->state) == XFRST_SOAQUERY ||
atomic_load(&xfr->state) == XFRST_INITIALSOA) &&
msg->counts[DNS_SECTION_QUESTION] != 1)
{
xfrin_log(xfr, ISC_LOG_NOTICE, "missing question section");
@ -1633,7 +1649,7 @@ xfrin_recv_done(isc_result_t result, isc_region_t *region, void *arg) {
* if the first RR in the answer section is not a SOA record.
*/
if (xfr->reqtype == dns_rdatatype_ixfr &&
xfr->state == XFRST_INITIALSOA &&
atomic_load(&xfr->state) == XFRST_INITIALSOA &&
msg->counts[DNS_SECTION_ANSWER] == 0)
{
xfrin_log(xfr, ISC_LOG_DEBUG(3),
@ -1700,24 +1716,29 @@ xfrin_recv_done(isc_result_t result, isc_region_t *region, void *arg) {
CHECK(dns_message_getquerytsig(msg, xfr->mctx, &xfr->lasttsig));
} else if (dns_message_gettsigkey(msg) != NULL) {
xfr->sincetsig++;
LOCK(&xfr->statslock);
if (xfr->sincetsig > 100 || xfr->nmsg == 0 ||
xfr->state == XFRST_AXFR_END ||
xfr->state == XFRST_IXFR_END)
atomic_load(&xfr->state) == XFRST_AXFR_END ||
atomic_load(&xfr->state) == XFRST_IXFR_END)
{
UNLOCK(&xfr->statslock);
result = DNS_R_EXPECTEDTSIG;
goto failure;
}
UNLOCK(&xfr->statslock);
}
/*
* Update the number of messages received.
*/
LOCK(&xfr->statslock);
xfr->nmsg++;
/*
* Update the number of bytes received.
*/
xfr->nbytes += buffer.used;
UNLOCK(&xfr->statslock);
/*
* Take the context back.
@ -1730,10 +1751,10 @@ xfrin_recv_done(isc_result_t result, isc_region_t *region, void *arg) {
get_edns_expire(xfr, msg);
}
switch (xfr->state) {
switch (atomic_load(&xfr->state)) {
case XFRST_GOTSOA:
xfr->reqtype = dns_rdatatype_axfr;
xfr->state = XFRST_INITIALSOA;
atomic_store(&xfr->state, XFRST_INITIALSOA);
CHECK(xfrin_send_request(xfr));
break;
case XFRST_AXFR_END:
@ -1826,6 +1847,7 @@ xfrin_destroy(dns_xfrin_t *xfr) {
if (msecs == 0) {
msecs = 1;
}
LOCK(&xfr->statslock);
persec = (xfr->nbytes * 1000) / msecs;
xfrin_log(xfr, ISC_LOG_INFO,
"Transfer completed: %d messages, %d records, "
@ -1834,6 +1856,8 @@ xfrin_destroy(dns_xfrin_t *xfr) {
xfr->nmsg, xfr->nrecs, xfr->nbytes,
(unsigned int)(msecs / 1000), (unsigned int)(msecs % 1000),
(unsigned int)persec, xfr->end_serial);
UNLOCK(&xfr->statslock);
isc_mutex_destroy(&xfr->statslock);
if (xfr->dispentry != NULL) {
dns_dispatch_done(&xfr->dispentry);