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Merge branch '4072-tcp-dispatch-timeout' into 'main'

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fix handling of TCP timeouts

Closes #4072

See merge request isc-projects/bind9!7937
This commit is contained in:
Evan Hunt
2023-05-26 08:49:52 +00:00
parent 2f75605698 0e800467ee
commit ee5ee5a994
1 changed files with 31 additions and 25 deletions
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56
lib/dns/dispatch.c
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@@ -207,6 +207,8 @@ qid_destroy(isc_mem_t *mctx, dns_qid_t **qidp);
static void
udp_startrecv(isc_nmhandle_t *handle, dns_dispentry_t *resp);
static void
udp_dispatch_connect(dns_dispatch_t *disp, dns_dispentry_t *resp);
static void
tcp_startrecv(dns_dispatch_t *disp, dns_dispentry_t *resp);
static void
tcp_dispatch_getnext(dns_dispatch_t *disp, dns_dispentry_t *resp,
@@ -490,19 +492,15 @@ ISC_REFCOUNT_IMPL(dns_dispentry, dispentry_destroy);
/*
* How long in milliseconds has it been since this dispentry
* started reading? (Only used for UDP, to adjust the timeout
* downward when running getnext.)
* started reading?
*/
static unsigned int
dispentry_runtime(dns_dispentry_t *resp) {
isc_time_t now;
dispentry_runtime(dns_dispentry_t *resp, const isc_time_t *now) {
if (isc_time_isepoch(&resp->start)) {
return (0);
}
now = isc_time_now();
return (isc_time_microdiff(&now, &resp->start) / 1000);
return (isc_time_microdiff(now, &resp->start) / 1000);
}
/*
@@ -532,6 +530,7 @@ udp_recv(isc_nmhandle_t *handle, isc_result_t eresult, isc_region_t *region,
isc_netaddr_t netaddr;
int match, timeout = 0;
bool respond = true;
isc_time_t now;
REQUIRE(VALID_RESPONSE(resp));
REQUIRE(VALID_DISPATCH(resp->disp));
@@ -631,7 +630,8 @@ next:
* This is the wrong response. Check whether there is still enough
* time to wait for the correct one to arrive before the timeout fires.
*/
timeout = resp->timeout - dispentry_runtime(resp);
now = isc_time_now();
timeout = resp->timeout - dispentry_runtime(resp, &now);
if (timeout <= 0) {
/*
* The time window for receiving the correct response is
@@ -803,6 +803,8 @@ tcp_recv(isc_nmhandle_t *handle, isc_result_t result, isc_region_t *region,
char buf[ISC_SOCKADDR_FORMATSIZE];
isc_sockaddr_t peer;
dns_displist_t resps = ISC_LIST_INITIALIZER;
isc_time_t now = isc_time_now();
int timeout;
REQUIRE(VALID_DISPATCH(disp));
@@ -862,8 +864,7 @@ tcp_recv(isc_nmhandle_t *handle, isc_result_t result, isc_region_t *region,
for (resp = ISC_LIST_HEAD(disp->active); resp != NULL; resp = next) {
next = ISC_LIST_NEXT(resp, alink);
/* FIXME: dispentry_runtime is always 0 for TCP */
int timeout = resp->timeout - dispentry_runtime(resp);
timeout = resp->timeout - dispentry_runtime(resp, &now);
if (timeout <= 0) {
tcp_recv_add(&resps, resp, ISC_R_TIMEDOUT);
}
@@ -900,8 +901,12 @@ tcp_recv(isc_nmhandle_t *handle, isc_result_t result, isc_region_t *region,
/*
* Phase 5: Resume reading if there are still active responses
*/
if (!ISC_LIST_EMPTY(disp->active)) {
tcp_startrecv(disp, ISC_LIST_HEAD(disp->active));
resp = ISC_LIST_HEAD(disp->active);
if (resp != NULL) {
timeout = resp->timeout - dispentry_runtime(resp, &now);
INSIST(timeout > 0);
tcp_startrecv(disp, resp);
isc_nmhandle_settimeout(handle, timeout);
}
UNLOCK(&disp->lock);
@@ -1485,7 +1490,7 @@ dns_dispatch_add(dns_dispatch_t *disp, unsigned int options,
#if DNS_DISPATCH_TRACE
fprintf(stderr, "dns_dispentry__init:%s:%s:%d:%p->references = 1\n",
__func__, __FILE__, __LINE__, res);
__func__, __FILE__, __LINE__, resp);
#endif
isc_refcount_init(&resp->references, 1); /* DISPENTRY000 */
@@ -1576,24 +1581,23 @@ dns_dispatch_getnext(dns_dispentry_t *resp) {
dispentry_log(resp, LVL(90), "getnext for QID %d", resp->id);
isc_time_t now = isc_time_now();
timeout = resp->timeout - dispentry_runtime(resp, &now);
if (timeout <= 0) {
return (ISC_R_TIMEDOUT);
}
LOCK(&disp->lock);
switch (disp->socktype) {
case isc_socktype_udp: {
timeout = resp->timeout - dispentry_runtime(resp);
if (timeout <= 0) {
result = ISC_R_TIMEDOUT;
break;
}
case isc_socktype_udp:
udp_dispatch_getnext(resp, timeout);
break;
}
case isc_socktype_tcp:
tcp_dispatch_getnext(disp, resp, timeout);
break;
default:
UNREACHABLE();
}
UNLOCK(&disp->lock);
return (result);
@@ -1801,7 +1805,6 @@ static void
udp_startrecv(isc_nmhandle_t *handle, dns_dispentry_t *resp) {
REQUIRE(VALID_RESPONSE(resp));
resp->start = isc_time_now();
dispentry_log(resp, LVL(90), "attaching handle %p to %p", handle,
&resp->handle);
isc_nmhandle_attach(handle, &resp->handle);
@@ -1819,6 +1822,7 @@ tcp_startrecv(dns_dispatch_t *disp, dns_dispentry_t *resp) {
dns_dispatch_ref(disp); /* DISPATCH002 */
if (resp != NULL) {
dispentry_log(resp, LVL(90), "reading from %p", disp->handle);
INSIST(!isc_time_isepoch(&resp->start));
} else {
dispatch_log(disp, LVL(90),
"TCP reading without response from %p",
@@ -1908,9 +1912,6 @@ tcp_connected(isc_nmhandle_t *handle, isc_result_t eresult, void *arg) {
dns_dispatch_detach(&disp); /* DISPATCH003 */
}
static void
udp_dispatch_connect(dns_dispatch_t *disp, dns_dispentry_t *resp);
static void
udp_connected(isc_nmhandle_t *handle, isc_result_t eresult, void *arg) {
dns_dispentry_t *resp = (dns_dispentry_t *)arg;
@@ -1974,9 +1975,11 @@ static void
udp_dispatch_connect(dns_dispatch_t *disp, dns_dispentry_t *resp) {
LOCK(&disp->lock);
resp->state = DNS_DISPATCHSTATE_CONNECTING;
resp->start = isc_time_now();
dns_dispentry_ref(resp); /* DISPENTRY004 */
ISC_LIST_APPEND(disp->pending, resp, plink);
UNLOCK(&disp->lock);
isc_nm_udpconnect(disp->mgr->nm, &resp->local, &resp->peer,
udp_connected, resp, resp->timeout);
}
@@ -2011,6 +2014,7 @@ tcp_dispatch_connect(dns_dispatch_t *disp, dns_dispentry_t *resp) {
/* First connection, continue with connecting */
disp->state = DNS_DISPATCHSTATE_CONNECTING;
resp->state = DNS_DISPATCHSTATE_CONNECTING;
resp->start = isc_time_now();
dns_dispentry_ref(resp); /* DISPENTRY005 */
ISC_LIST_APPEND(disp->pending, resp, plink);
UNLOCK(&disp->lock);
@@ -2036,6 +2040,7 @@ tcp_dispatch_connect(dns_dispatch_t *disp, dns_dispentry_t *resp) {
case DNS_DISPATCHSTATE_CONNECTING:
/* Connection pending; add resp to the list */
resp->state = DNS_DISPATCHSTATE_CONNECTING;
resp->start = isc_time_now();
dns_dispentry_ref(resp); /* DISPENTRY005 */
ISC_LIST_APPEND(disp->pending, resp, plink);
UNLOCK(&disp->lock);
@@ -2043,6 +2048,7 @@ tcp_dispatch_connect(dns_dispatch_t *disp, dns_dispentry_t *resp) {
case DNS_DISPATCHSTATE_CONNECTED:
resp->state = DNS_DISPATCHSTATE_CONNECTED;
resp->start = isc_time_now();
/* Add the resp to the reading list */
ISC_LIST_APPEND(disp->active, resp, alink);