restore allowance for tcp-clients < interfaces

in the "refactor tcpquota and pipeline refs" commit, the counting
of active interfaces was tightened in such a way that named could
fail to listen on an interface if there were more interfaces than
tcp-clients. when checking the quota to start accepting on an
interface, if the number of active clients was above zero, then
it was presumed that some other client was able to handle accepting
new connections. this, however, ignored the fact that the current client
could be included in that count, so if the quota was already exceeded
before all the interfaces were listening, some interfaces would never
listen.

we now check whether the current client has been marked active; if so,
then the number of active clients on the interface must be greater
than 1, not 0.

(cherry picked from commit 71fead4c3e03b178d6e6e3ff7592b45cf5f94069)
(cherry picked from commit 785658728ad29ef497fb6770d0688d07f55ab5c5)

diff --git a/doc/arm/Bv9ARM-book.xml b/doc/arm/Bv9ARM-book.xml
index fc5d5c63f85705c182d5efc866bfbf6a6849bd40..49d8f998a6fa3804ceda5bdc5015cfcaf36462ca 100644 (file)
--- a/doc/arm/Bv9ARM-book.xml
+++ b/doc/arm/Bv9ARM-book.xml
@@ -8424,7 +8424,8 @@ avoid-v6-udp-ports { 40000; range 50000 60000; };
                <para>
                  The number of file descriptors reserved for TCP, stdio,
                  etc.  This needs to be big enough to cover the number of
-                 interfaces <command>named</command> listens on, <command>tcp-clients</command> as well as
+                 interfaces <command>named</command> listens on plus
+                 <command>tcp-clients</command>, as well as
                  to provide room for outgoing TCP queries and incoming zone
                  transfers.  The default is <literal>512</literal>.
                  The minimum value is <literal>128</literal> and the

diff --git a/lib/ns/client.c b/lib/ns/client.c
index 665dcaf507c026852fa2cf0a22afce95a6c44bfb..d8ab3ce9c69e7aa41389edec53289134feed9e29 100644 (file)
--- a/lib/ns/client.c
+++ b/lib/ns/client.c
@@ -3441,8 +3441,9 @@ client_accept(ns_client_t *client) {
                 *
                 * So, we check here to see if any other clients are
                 * already servicing TCP queries on this interface (whether
-                * accepting, reading, or processing). If we find at least
-                * one, then it's okay *not* to call accept - we can let this
+                * accepting, reading, or processing). If we find that at
+                * least one client other than this one is active, then
+                * it's okay *not* to call accept - we can let this
                 * client go inactive and another will take over when it's
                 * done.
                 *
@@ -3456,7 +3457,8 @@ client_accept(ns_client_t *client) {
                 * quota is tcp-clients plus the number of listening
                 * interfaces plus 1.)
                 */
-               exit = (isc_atomic_xadd(&client->interface->ntcpactive, 0) > 0);
+               exit = (isc_atomic_xadd(&client->interface->ntcpactive, 0) >
+                       (client->tcpactive ? 1 : 0));
                if (exit) {
                        client->newstate = NS_CLIENTSTATE_INACTIVE;
                        (void)exit_check(client);