Clone the csock in accept_connection(), not in callback

If we clone the csock (children socket) in TCP accept_connection()
instead of passing the ssock (server socket) to the call back and
cloning it there we unbreak the assumption that every socket is handled
inside it's own worker thread and therefore we can get rid of (at least)
callback locking.

diff --git a/lib/isc/netmgr/netmgr.c b/lib/isc/netmgr/netmgr.c
index 6ee8bb72885d7bd7178b5731e7cb2c253263ebca..c1eb14005aeca4f10e482d56d7ebc0fcb91f5b81 100644 (file)
--- a/lib/isc/netmgr/netmgr.c
+++ b/lib/isc/netmgr/netmgr.c
@@ -1040,6 +1040,7 @@ isc__nmsocket_init(isc_nmsocket_t *sock, isc_nm_t *mgr, isc_nmsocket_type type,
 void
 isc__nmsocket_clearcb(isc_nmsocket_t *sock) {
        REQUIRE(VALID_NMSOCK(sock));
+       REQUIRE(!isc__nm_in_netthread() || sock->tid == isc_nm_tid());
 
        sock->recv_cb = NULL;
        sock->recv_cbarg = NULL;

diff --git a/lib/isc/netmgr/tcp.c b/lib/isc/netmgr/tcp.c
index cb7331d342fbb1c7f6a02be823d1003dd05bdfdc..208e703d07a550e2072f5e16219e0ca8846aa2b9 100644 (file)
--- a/lib/isc/netmgr/tcp.c
+++ b/lib/isc/netmgr/tcp.c
@@ -431,8 +431,7 @@ void
 isc__nm_async_tcpchildaccept(isc__networker_t *worker, isc__netievent_t *ev0) {
        isc__netievent_tcpchildaccept_t *ievent =
                (isc__netievent_tcpchildaccept_t *)ev0;
-       isc_nmsocket_t *ssock = ievent->sock;
-       isc_nmsocket_t *csock = NULL;
+       isc_nmsocket_t *sock = ievent->sock;
        isc_nmhandle_t *handle;
        isc_result_t result;
        struct sockaddr_storage ss;
@@ -442,20 +441,15 @@ isc__nm_async_tcpchildaccept(isc__networker_t *worker, isc__netievent_t *ev0) {
        void *accept_cbarg;
 
        REQUIRE(isc__nm_in_netthread());
-       REQUIRE(ssock->type == isc_nm_tcplistener);
-
-       csock = isc_mem_get(ssock->mgr->mctx, sizeof(isc_nmsocket_t));
-       isc__nmsocket_init(csock, ssock->mgr, isc_nm_tcpsocket, ssock->iface);
-       csock->tid = isc_nm_tid();
-       csock->extrahandlesize = ssock->extrahandlesize;
+       REQUIRE(sock->tid == isc_nm_tid());
 
-       csock->quota = ievent->quota;
+       sock->quota = ievent->quota;
        ievent->quota = NULL;
 
-       worker = &ssock->mgr->workers[isc_nm_tid()];
-       uv_tcp_init(&worker->loop, &csock->uv_handle.tcp);
+       worker = &sock->mgr->workers[isc_nm_tid()];
+       uv_tcp_init(&worker->loop, &sock->uv_handle.tcp);
 
-       r = isc_uv_import(&csock->uv_handle.stream, &ievent->streaminfo);
+       r = isc_uv_import(&sock->uv_handle.stream, &ievent->streaminfo);
        if (r != 0) {
                isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
                              ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
@@ -465,20 +459,19 @@ isc__nm_async_tcpchildaccept(isc__networker_t *worker, isc__netievent_t *ev0) {
                goto error;
        }
 
-       r = uv_tcp_getpeername(&csock->uv_handle.tcp, (struct sockaddr *)&ss,
+       r = uv_tcp_getpeername(&sock->uv_handle.tcp, (struct sockaddr *)&ss,
                               &(int){ sizeof(ss) });
        if (r != 0) {
                result = isc__nm_uverr2result(r);
                goto error;
        }
 
-       result = isc_sockaddr_fromsockaddr(&csock->peer,
-                                          (struct sockaddr *)&ss);
+       result = isc_sockaddr_fromsockaddr(&sock->peer, (struct sockaddr *)&ss);
        if (result != ISC_R_SUCCESS) {
                goto error;
        }
 
-       r = uv_tcp_getsockname(&csock->uv_handle.tcp, (struct sockaddr *)&ss,
+       r = uv_tcp_getsockname(&sock->uv_handle.tcp, (struct sockaddr *)&ss,
                               &(int){ sizeof(ss) });
        if (r != 0) {
                result = isc__nm_uverr2result(r);
@@ -490,23 +483,19 @@ isc__nm_async_tcpchildaccept(isc__networker_t *worker, isc__netievent_t *ev0) {
                goto error;
        }
 
-       isc__nmsocket_attach(ssock, &csock->server);
+       handle = isc__nmhandle_get(sock, NULL, &local);
 
-       handle = isc__nmhandle_get(csock, NULL, &local);
+       INSIST(sock->accept_cb != NULL);
+       accept_cb = sock->accept_cb;
+       accept_cbarg = sock->accept_cbarg;
 
-       LOCK(&ssock->lock);
-       INSIST(ssock->accept_cb != NULL);
-       accept_cb = ssock->accept_cb;
-       accept_cbarg = ssock->accept_cbarg;
-       UNLOCK(&ssock->lock);
-
-       csock->read_timeout = ssock->mgr->init;
+       sock->read_timeout = sock->mgr->init;
        accept_cb(handle, ISC_R_SUCCESS, accept_cbarg);
 
        /*
-        * csock is now attached to the handle.
+        * sock is now attached to the handle.
         */
-       isc__nmsocket_detach(&csock);
+       isc__nmsocket_detach(&sock);
 
        /*
         * The accept callback should have attached to the handle.
@@ -521,8 +510,8 @@ error:
         * otherwise it'd be detached later asynchronously, and clog
         * the quota unnecessarily.
         */
-       if (csock->quota != NULL) {
-               isc_quota_detach(&csock->quota);
+       if (sock->quota != NULL) {
+               isc_quota_detach(&sock->quota);
        }
        isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL, ISC_LOGMODULE_NETMGR,
                      ISC_LOG_ERROR, "Accepting TCP connection failed: %s",
@@ -531,7 +520,7 @@ error:
        /*
         * Detach the socket properly to make sure uv_close() is called.
         */
-       isc__nmsocket_detach(&csock);
+       isc__nmsocket_detach(&sock);
 }
 
 void
@@ -616,11 +605,9 @@ readtimeout_cb(uv_timer_t *handle) {
                isc_quota_detach(&sock->quota);
        }
 
-       LOCK(&sock->lock);
        cb = sock->recv_cb;
        cbarg = sock->recv_cbarg;
        isc__nmsocket_clearcb(sock);
-       UNLOCK(&sock->lock);
 
        if (cb != NULL) {
                cb(sock->statichandle, ISC_R_TIMEDOUT, NULL, cbarg);
@@ -637,10 +624,9 @@ isc__nm_tcp_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg) {
 
        sock = handle->sock;
 
-       LOCK(&sock->lock);
+       REQUIRE(sock->tid == isc_nm_tid());
        sock->recv_cb = cb;
        sock->recv_cbarg = cbarg;
-       UNLOCK(&sock->lock);
 
        ievent = isc__nm_get_ievent(sock->mgr, netievent_tcpstartread);
        ievent->sock = sock;
@@ -749,12 +735,11 @@ isc__nm_tcp_resumeread(isc_nmsocket_t *sock) {
        isc__netievent_startread_t *ievent = NULL;
 
        REQUIRE(VALID_NMSOCK(sock));
-       LOCK(&sock->lock);
+       REQUIRE(sock->tid == isc_nm_tid());
+
        if (sock->recv_cb == NULL) {
-               UNLOCK(&sock->lock);
                return (ISC_R_CANCELED);
        }
-       UNLOCK(&sock->lock);
 
        if (!atomic_load(&sock->readpaused)) {
                return (ISC_R_SUCCESS);
@@ -784,12 +769,11 @@ read_cb(uv_stream_t *stream, ssize_t nread, const uv_buf_t *buf) {
        void *cbarg;
 
        REQUIRE(VALID_NMSOCK(sock));
+       REQUIRE(sock->tid == isc_nm_tid());
        REQUIRE(buf != NULL);
 
-       LOCK(&sock->lock);
        cb = sock->recv_cb;
        cbarg = sock->recv_cbarg;
-       UNLOCK(&sock->lock);
 
        if (nread >= 0) {
                isc_region_t region = { .base = (unsigned char *)buf->base,
@@ -895,7 +879,6 @@ accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota) {
        int r, w;
 
        REQUIRE(VALID_NMSOCK(ssock));
-       REQUIRE(ssock->tid == isc_nm_tid());
 
        if (!atomic_load_relaxed(&ssock->active) ||
            atomic_load_relaxed(&ssock->mgr->closing))
@@ -955,7 +938,18 @@ accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota) {
        /* We have an accepted TCP socket, pass it to a random worker */
        w = isc_random_uniform(ssock->mgr->nworkers);
        event = isc__nm_get_ievent(ssock->mgr, netievent_tcpchildaccept);
-       event->sock = ssock;
+
+       /* Duplicate the server socket */
+       isc_nmsocket_t *csock = isc_mem_get(ssock->mgr->mctx,
+                                           sizeof(isc_nmsocket_t));
+       isc__nmsocket_init(csock, ssock->mgr, isc_nm_tcpsocket, ssock->iface);
+       csock->tid = w;
+       csock->extrahandlesize = ssock->extrahandlesize;
+       isc__nmsocket_attach(ssock, &csock->server);
+       csock->accept_cb = ssock->accept_cb;
+       csock->accept_cbarg = ssock->accept_cbarg;
+
+       event->sock = csock;
        event->quota = quota;
 
        r = isc_uv_export((uv_stream_t *)uvstream, &event->streaminfo);
@@ -1149,16 +1143,15 @@ isc__nm_async_tcpclose(isc__networker_t *worker, isc__netievent_t *ev0) {
 void
 isc__nm_tcp_shutdown(isc_nmsocket_t *sock) {
        REQUIRE(VALID_NMSOCK(sock));
+       REQUIRE(sock->tid == isc_nm_tid());
 
        if (sock->type == isc_nm_tcpsocket && sock->statichandle != NULL) {
                isc_nm_recv_cb_t cb;
                void *cbarg;
 
-               LOCK(&sock->lock);
                cb = sock->recv_cb;
                cbarg = sock->recv_cbarg;
                isc__nmsocket_clearcb(sock);
-               UNLOCK(&sock->lock);
 
                if (cb != NULL) {
                        cb(sock->statichandle, ISC_R_CANCELED, NULL, cbarg);
@@ -1176,16 +1169,15 @@ isc__nm_tcp_cancelread(isc_nmhandle_t *handle) {
 
        REQUIRE(VALID_NMSOCK(sock));
        REQUIRE(sock->type == isc_nm_tcpsocket);
+       REQUIRE(sock->tid == isc_nm_tid());
 
        if (atomic_load(&sock->client)) {
                isc_nm_recv_cb_t cb;
                void *cbarg;
 
-               LOCK(&sock->lock);
                cb = sock->recv_cb;
                cbarg = sock->recv_cbarg;
                isc__nmsocket_clearcb(sock);
-               UNLOCK(&sock->lock);
 
                cb(handle, ISC_R_EOF, NULL, cbarg);
        }

diff --git a/lib/isc/netmgr/tcpdns.c b/lib/isc/netmgr/tcpdns.c
index 8060bbfe9a4be56fc702a7ef9f0b7ab0dbf105f6..283f77665ed553a9735e0e4cd214bef987d39445 100644 (file)
--- a/lib/isc/netmgr/tcpdns.c
+++ b/lib/isc/netmgr/tcpdns.c
@@ -119,10 +119,8 @@ dnslisten_acceptcb(isc_nmhandle_t *handle, isc_result_t result, void *cbarg) {
                return (result);
        }
 
-       LOCK(&dnslistensock->lock);
        accept_cb = dnslistensock->accept_cb;
        accept_cbarg = dnslistensock->accept_cbarg;
-       UNLOCK(&dnslistensock->lock);
 
        if (accept_cb != NULL) {
                result = accept_cb(handle, ISC_R_SUCCESS, accept_cbarg);
@@ -184,6 +182,7 @@ processbuffer(isc_nmsocket_t *dnssock, isc_nmhandle_t **handlep) {
        size_t len;
 
        REQUIRE(VALID_NMSOCK(dnssock));
+       REQUIRE(dnssock->tid == isc_nm_tid());
        REQUIRE(handlep != NULL && *handlep == NULL);
 
        /*
@@ -214,12 +213,9 @@ processbuffer(isc_nmsocket_t *dnssock, isc_nmhandle_t **handlep) {
 
                listener = dnssock->listener;
                if (listener != NULL) {
-                       LOCK(&listener->lock);
                        cb = listener->recv_cb;
                        cbarg = listener->recv_cbarg;
-                       UNLOCK(&listener->lock);
                } else if (dnssock->recv_cb != NULL) {
-                       LOCK(&dnssock->lock);
                        cb = dnssock->recv_cb;
                        cbarg = dnssock->recv_cbarg;
                        /*
@@ -228,7 +224,6 @@ processbuffer(isc_nmsocket_t *dnssock, isc_nmhandle_t **handlep) {
                         * call to isc_nm_read() and set up a new callback.
                         */
                        isc__nmsocket_clearcb(dnssock);
-                       UNLOCK(&dnssock->lock);
                }
 
                if (cb != NULL) {
@@ -265,6 +260,7 @@ dnslisten_readcb(isc_nmhandle_t *handle, isc_result_t eresult,
        size_t len;
 
        REQUIRE(VALID_NMSOCK(dnssock));
+       REQUIRE(dnssock->tid == isc_nm_tid());
        REQUIRE(VALID_NMHANDLE(handle));
 
        if (region == NULL || eresult != ISC_R_SUCCESS) {
@@ -314,10 +310,8 @@ dnslisten_readcb(isc_nmhandle_t *handle, isc_result_t eresult,
                        uv_timer_stop(&dnssock->timer);
                }
 
-               LOCK(&dnssock->lock);
                if (atomic_load(&dnssock->sequential) ||
                    dnssock->recv_cb == NULL) {
-                       UNLOCK(&dnssock->lock);
                        /*
                         * There are two reasons we might want to pause here:
                         * - We're in sequential mode and we've received
@@ -328,7 +322,6 @@ dnslisten_readcb(isc_nmhandle_t *handle, isc_result_t eresult,
                        isc_nm_pauseread(dnssock->outerhandle);
                        done = true;
                } else {
-                       UNLOCK(&dnssock->lock);
                        /*
                         * We're pipelining, so we now resume processing
                         * packets until the clients-per-connection limit
@@ -364,12 +357,10 @@ isc_nm_listentcpdns(isc_nm_t *mgr, isc_nmiface_t *iface, isc_nm_recv_cb_t cb,
        REQUIRE(VALID_NM(mgr));
 
        isc__nmsocket_init(dnslistensock, mgr, isc_nm_tcpdnslistener, iface);
-       LOCK(&dnslistensock->lock);
        dnslistensock->recv_cb = cb;
        dnslistensock->recv_cbarg = cbarg;
        dnslistensock->accept_cb = accept_cb;
        dnslistensock->accept_cbarg = accept_cbarg;
-       UNLOCK(&dnslistensock->lock);
        dnslistensock->extrahandlesize = extrahandlesize;
 
        /*
@@ -558,6 +549,7 @@ isc__nm_async_tcpdnssend(isc__networker_t *worker, isc__netievent_t *ev0) {
        isc_nmsocket_t *sock = ievent->sock;
 
        REQUIRE(worker->id == sock->tid);
+       REQUIRE(sock->tid == isc_nm_tid());
 
        result = ISC_R_NOTCONNECTED;
        if (atomic_load(&sock->active) && sock->outerhandle != NULL) {

diff --git a/lib/isc/netmgr/udp.c b/lib/isc/netmgr/udp.c
index b6785935f195bed662905b57879213ed1bfc2447..f87ab95a5fcc9d2dcc90205c901ad349a7987e22 100644 (file)
--- a/lib/isc/netmgr/udp.c
+++ b/lib/isc/netmgr/udp.c
@@ -379,12 +379,7 @@ udp_recv_cb(uv_udp_t *handle, ssize_t nrecv, const uv_buf_t *buf,
        region.base = (unsigned char *)buf->base;
        region.length = nrecv;
 
-       /*
-        * In tcp.c and tcpdns.c, this would need to be locked
-        * by sock->lock because callbacks may be set to NULL
-        * unexpectedly when the connection drops, but that isn't
-        * a factor in the UDP case.
-        */
+       INSIST(sock->tid == isc_nm_tid());
        INSIST(sock->recv_cb != NULL);
        cb = sock->recv_cb;
        cbarg = sock->recv_cbarg;