Update to FreeBSD 9.2

1 files changed, 189 insertions, 120 deletions

diff --git a/freebsd/sys/kern/uipc_socket.c b/freebsd/sys/kern/uipc_socket.c
index 227e6dac..9ca2c14c 100644
--- a/freebsd/sys/kern/uipc_socket.c
+++ b/freebsd/sys/kern/uipc_socket.c
@@ -137,6 +137,8 @@ __FBSDID("$FreeBSD$");
 #include <sys/sysctl.h>
 #include <sys/uio.h>
 #include <sys/jail.h>
+#include <sys/syslog.h>
+#include <netinet/in.h>
 
 #include <net/vnet.h>
 
@@ -159,18 +161,24 @@ static void	filt_sowdetach(struct knote *kn);
 static int	filt_sowrite(struct knote *kn, long hint);
 static int	filt_solisten(struct knote *kn, long hint);
 
-static struct filterops solisten_filtops =
-	{ 1, NULL, filt_sordetach, filt_solisten };
-static struct filterops soread_filtops =
-	{ 1, NULL, filt_sordetach, filt_soread };
-static struct filterops sowrite_filtops =
-	{ 1, NULL, filt_sowdetach, filt_sowrite };
+static struct filterops solisten_filtops = {
+	.f_isfd = 1,
+	.f_detach = filt_sordetach,
+	.f_event = filt_solisten,
+};
+static struct filterops soread_filtops = {
+	.f_isfd = 1,
+	.f_detach = filt_sordetach,
+	.f_event = filt_soread,
+};
+static struct filterops sowrite_filtops = {
+	.f_isfd = 1,
+	.f_detach = filt_sowdetach,
+	.f_event = filt_sowrite,
+};
 
-uma_zone_t socket_zone;
 so_gen_t	so_gencnt;	/* generation count for sockets */
 
-int	maxsockets;
-
 MALLOC_DEFINE(M_SONAME, "soname", "socket name");
 MALLOC_DEFINE(M_PCB, "pcb", "protocol control block");
 
@@ -178,15 +186,37 @@ MALLOC_DEFINE(M_PCB, "pcb", "protocol control block");
 	VNET_ASSERT(curvnet != NULL,					\
 	    ("%s:%d curvnet is NULL, so=%p", __func__, __LINE__, (so)));
 
+/*
+ * Limit on the number of connections in the listen queue waiting
+ * for accept(2).
+ */
 static int somaxconn = SOMAXCONN;
-static int sysctl_somaxconn(SYSCTL_HANDLER_ARGS);
-/* XXX: we dont have SYSCTL_USHORT */
+
+static int
+sysctl_somaxconn(SYSCTL_HANDLER_ARGS)
+{
+	int error;
+	int val;
+
+	val = somaxconn;
+	error = sysctl_handle_int(oidp, &val, 0, req);
+	if (error || !req->newptr )
+		return (error);
+
+	if (val < 1 || val > USHRT_MAX)
+		return (EINVAL);
+
+	somaxconn = val;
+	return (0);
+}
 SYSCTL_PROC(_kern_ipc, KIPC_SOMAXCONN, somaxconn, CTLTYPE_UINT | CTLFLAG_RW,
-    0, sizeof(int), sysctl_somaxconn, "I", "Maximum pending socket connection "
-    "queue size");
+    0, sizeof(int), sysctl_somaxconn, "I",
+    "Maximum listen socket pending connection accept queue size");
+
 static int numopensockets;
 SYSCTL_INT(_kern_ipc, OID_AUTO, numopensockets, CTLFLAG_RD,
     &numopensockets, 0, "Number of open sockets");
+
 #ifdef ZERO_COPY_SOCKETS
 /* These aren't static because they're used in other files. */
 int so_zero_copy_send = 1;
@@ -220,6 +250,49 @@ MTX_SYSINIT(so_global_mtx, &so_global_mtx, "so_glabel", MTX_DEF);
 SYSCTL_NODE(_kern, KERN_IPC, ipc, CTLFLAG_RW, 0, "IPC");
 
 /*
+ * Initialize the socket subsystem and set up the socket
+ * memory allocator.
+ */
+uma_zone_t socket_zone;
+int	maxsockets;
+
+static void
+socket_zone_change(void *tag)
+{
+
+	uma_zone_set_max(socket_zone, maxsockets);
+}
+
+static void
+socket_init(void *tag)
+{
+
+        socket_zone = uma_zcreate("socket", sizeof(struct socket), NULL, NULL,
+            NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
+        uma_zone_set_max(socket_zone, maxsockets);
+        EVENTHANDLER_REGISTER(maxsockets_change, socket_zone_change, NULL,
+                EVENTHANDLER_PRI_FIRST);
+}
+SYSINIT(socket, SI_SUB_PROTO_DOMAININIT, SI_ORDER_ANY, socket_init, NULL);
+
+/*
+ * Initialise maxsockets.  This SYSINIT must be run after
+ * tunable_mbinit().
+ */
+static void
+init_maxsockets(void *ignored)
+{
+
+	TUNABLE_INT_FETCH("kern.ipc.maxsockets", &maxsockets);
+#ifndef __rtems__
+	maxsockets = imax(maxsockets, imax(maxfiles, nmbclusters));
+#else /* __rtems__ */
+	maxsockets = imax(maxsockets, nmbclusters);
+#endif /* __rtems__ */
+}
+SYSINIT(param, SI_SUB_TUNABLES, SI_ORDER_ANY, init_maxsockets, NULL);
+
+/*
  * Sysctl to get and set the maximum global sockets limit.  Notify protocols
  * of the change so that they can update their dependent limits as required.
  */
@@ -245,29 +318,11 @@ sysctl_maxsockets(SYSCTL_HANDLER_ARGS)
 	}
 	return (error);
 }
-
 SYSCTL_PROC(_kern_ipc, OID_AUTO, maxsockets, CTLTYPE_INT|CTLFLAG_RW,
     &maxsockets, 0, sysctl_maxsockets, "IU",
     "Maximum number of sockets avaliable");
 
 /*
- * Initialise maxsockets.  This SYSINIT must be run after
- * tunable_mbinit().
- */
-static void
-init_maxsockets(void *ignored)
-{
-
-	TUNABLE_INT_FETCH("kern.ipc.maxsockets", &maxsockets);
-#ifndef __rtems__
-	maxsockets = imax(maxsockets, imax(maxfiles, nmbclusters));
-#else /* __rtems__ */
-	maxsockets = imax(maxsockets, nmbclusters);
-#endif /* __rtems__ */
-}
-SYSINIT(param, SI_SUB_TUNABLES, SI_ORDER_ANY, init_maxsockets, NULL);
-
-/*
  * Socket operation routines.  These routines are called by the routines in
  * sys_socket.c or from a system process, and implement the semantics of
  * socket operations by switching out to the protocol specific routines.
@@ -450,16 +505,24 @@ sonewconn(struct socket *head, int connstatus)
 	over = (head->so_qlen > 3 * head->so_qlimit / 2);
 	ACCEPT_UNLOCK();
 #ifdef REGRESSION
-	if (regression_sonewconn_earlytest && over)
+	if (regression_sonewconn_earlytest && over) {
 #else
-	if (over)
+	if (over) {
 #endif
+		log(LOG_DEBUG, "%s: pcb %p: Listen queue overflow: "
+		    "%i already in queue awaiting acceptance\n",
+		    __func__, head->so_pcb, head->so_qlen);
 		return (NULL);
+	}
 	VNET_ASSERT(head->so_vnet != NULL, ("%s:%d so_vnet is NULL, head=%p",
 	    __func__, __LINE__, head));
 	so = soalloc(head->so_vnet);
-	if (so == NULL)
+	if (so == NULL) {
+		log(LOG_DEBUG, "%s: pcb %p: New socket allocation failure: "
+		    "limit reached or out of memory\n",
+		    __func__, head->so_pcb);
 		return (NULL);
+	}
 	if ((head->so_options & SO_ACCEPTFILTER) != 0)
 		connstatus = 0;
 	so->so_head = head;
@@ -476,9 +539,16 @@ sonewconn(struct socket *head, int connstatus)
 	knlist_init_mtx(&so->so_rcv.sb_sel.si_note, SOCKBUF_MTX(&so->so_rcv));
 	knlist_init_mtx(&so->so_snd.sb_sel.si_note, SOCKBUF_MTX(&so->so_snd));
 	VNET_SO_ASSERT(head);
-	if (soreserve(so, head->so_snd.sb_hiwat, head->so_rcv.sb_hiwat) ||
-	    (*so->so_proto->pr_usrreqs->pru_attach)(so, 0, NULL)) {
+	if (soreserve(so, head->so_snd.sb_hiwat, head->so_rcv.sb_hiwat)) {
 		sodealloc(so);
+		log(LOG_DEBUG, "%s: pcb %p: soreserve() failed\n",
+		    __func__, head->so_pcb);
+		return (NULL);
+	}
+	if ((*so->so_proto->pr_usrreqs->pru_attach)(so, 0, NULL)) {
+		sodealloc(so);
+		log(LOG_DEBUG, "%s: pcb %p: pru_attach() failed\n",
+		    __func__, head->so_pcb);
 		return (NULL);
 	}
 	so->so_rcv.sb_lowat = head->so_rcv.sb_lowat;
@@ -489,6 +559,20 @@ sonewconn(struct socket *head, int connstatus)
 	so->so_snd.sb_flags |= head->so_snd.sb_flags & SB_AUTOSIZE;
 	so->so_state |= connstatus;
 	ACCEPT_LOCK();
+	/*
+	 * The accept socket may be tearing down but we just
+	 * won a race on the ACCEPT_LOCK.
+	 * However, if sctp_peeloff() is called on a 1-to-many
+	 * style socket, the SO_ACCEPTCONN doesn't need to be set.
+	 */
+	if (!(head->so_options & SO_ACCEPTCONN) &&
+	    ((head->so_proto->pr_protocol != IPPROTO_SCTP) ||
+	     (head->so_type != SOCK_SEQPACKET))) {
+		SOCK_LOCK(so);
+		so->so_head = NULL;
+		sofree(so);		/* NB: returns ACCEPT_UNLOCK'ed. */
+		return (NULL);
+	}
 	if (connstatus) {
 		TAILQ_INSERT_TAIL(&head->so_comp, so, so_list);
 		so->so_qstate |= SQ_COMP;
@@ -583,9 +667,12 @@ solisten_proto(struct socket *so, int backlog)
 }
 
 /*
- * Attempt to free a socket.  This should really be sotryfree().
+ * Evaluate the reference count and named references on a socket; if no
+ * references remain, free it.  This should be called whenever a reference is
+ * released, such as in sorele(), but also when named reference flags are
+ * cleared in socket or protocol code.
  *
- * sofree() will succeed if:
+ * sofree() will free the socket if:
  *
  * - There are no outstanding file descriptor references or related consumers
  *   (so_count == 0).
@@ -598,9 +685,6 @@ solisten_proto(struct socket *so, int backlog)
  * - The socket is not in a completed connection queue, so a process has been
  *   notified that it is present.  If it is removed, the user process may
  *   block in accept() despite select() saying the socket was ready.
- *
- * Otherwise, it will quietly abort so that a future call to sofree(), when
- * conditions are right, can succeed.
  */
 void
 sofree(struct socket *so)
@@ -714,9 +798,14 @@ soclose(struct socket *so)
 drop:
 	if (so->so_proto->pr_usrreqs->pru_close != NULL)
 		(*so->so_proto->pr_usrreqs->pru_close)(so);
+	ACCEPT_LOCK();
 	if (so->so_options & SO_ACCEPTCONN) {
 		struct socket *sp;
-		ACCEPT_LOCK();
+		/*
+		 * Prevent new additions to the accept queues due
+		 * to ACCEPT_LOCK races while we are draining them.
+		 */
+		so->so_options &= ~SO_ACCEPTCONN;
 		while ((sp = TAILQ_FIRST(&so->so_incomp)) != NULL) {
 			TAILQ_REMOVE(&so->so_incomp, sp, so_list);
 			so->so_incqlen--;
@@ -735,13 +824,15 @@ drop:
 			soabort(sp);
 			ACCEPT_LOCK();
 		}
-		ACCEPT_UNLOCK();
+		KASSERT((TAILQ_EMPTY(&so->so_comp)),
+		    ("%s: so_comp populated", __func__));
+		KASSERT((TAILQ_EMPTY(&so->so_incomp)),
+		    ("%s: so_incomp populated", __func__));
 	}
-	ACCEPT_LOCK();
 	SOCK_LOCK(so);
 	KASSERT((so->so_state & SS_NOFDREF) == 0, ("soclose: NOFDREF"));
 	so->so_state |= SS_NOFDREF;
-	sorele(so);
+	sorele(so);			/* NB: Returns with ACCEPT_UNLOCK(). */
 	CURVNET_RESTORE();
 	return (error);
 }
@@ -863,12 +954,6 @@ struct so_zerocopy_stats{
 	int found_ifp;
 };
 struct so_zerocopy_stats so_zerocp_stats = {0,0,0};
-#include <netinet/in.h>
-#include <net/route.h>
-#include <netinet/in_pcb.h>
-#include <vm/vm.h>
-#include <vm/vm_page.h>
-#include <vm/vm_object.h>
 
 /*
  * sosend_copyin() is only used if zero copy sockets are enabled.  Otherwise
@@ -890,11 +975,10 @@ sosend_copyin(struct uio *uio, struct mbuf **retmp, int atomic, long *space,
     int flags)
 {
 	struct mbuf *m, **mp, *top;
-	long len, resid;
+	long len;
+	ssize_t resid;
 	int error;
-#ifdef ZERO_COPY_SOCKETS
 	int cow_send;
-#endif
 
 	*retmp = top = NULL;
 	mp = &top;
@@ -902,11 +986,8 @@ sosend_copyin(struct uio *uio, struct mbuf **retmp, int atomic, long *space,
 	resid = uio->uio_resid;
 	error = 0;
 	do {
-#ifdef ZERO_COPY_SOCKETS
 		cow_send = 0;
-#endif /* ZERO_COPY_SOCKETS */
 		if (resid >= MINCLSIZE) {
-#ifdef ZERO_COPY_SOCKETS
 			if (top == NULL) {
 				m = m_gethdr(M_WAITOK, MT_DATA);
 				m->m_pkthdr.len = 0;
@@ -914,9 +995,9 @@ sosend_copyin(struct uio *uio, struct mbuf **retmp, int atomic, long *space,
 			} else
 				m = m_get(M_WAITOK, MT_DATA);
 			if (so_zero_copy_send &&
-			    resid>=PAGE_SIZE &&
-			    *space>=PAGE_SIZE &&
-			    uio->uio_iov->iov_len>=PAGE_SIZE) {
+			    resid >= PAGE_SIZE &&
+			    *space >= PAGE_SIZE &&
+			    uio->uio_iov->iov_len >= PAGE_SIZE) {
 				so_zerocp_stats.size_ok++;
 				so_zerocp_stats.align_ok++;
 				cow_send = socow_setup(m, uio);
@@ -926,15 +1007,6 @@ sosend_copyin(struct uio *uio, struct mbuf **retmp, int atomic, long *space,
 				m_clget(m, M_WAITOK);
 				len = min(min(MCLBYTES, resid), *space);
 			}
-#else /* ZERO_COPY_SOCKETS */
-			if (top == NULL) {
-				m = m_getcl(M_WAIT, MT_DATA, M_PKTHDR);
-				m->m_pkthdr.len = 0;
-				m->m_pkthdr.rcvif = NULL;
-			} else
-				m = m_getcl(M_WAIT, MT_DATA, 0);
-			len = min(min(MCLBYTES, resid), *space);
-#endif /* ZERO_COPY_SOCKETS */
 		} else {
 			if (top == NULL) {
 				m = m_gethdr(M_WAIT, MT_DATA);
@@ -959,12 +1031,10 @@ sosend_copyin(struct uio *uio, struct mbuf **retmp, int atomic, long *space,
 		}
 
 		*space -= len;
-#ifdef ZERO_COPY_SOCKETS
 		if (cow_send)
 			error = 0;
 		else
-#endif /* ZERO_COPY_SOCKETS */
-		error = uiomove(mtod(m, void *), (int)len, uio);
+			error = uiomove(mtod(m, void *), (int)len, uio);
 		resid = uio->uio_resid;
 		m->m_len = len;
 		*mp = m;
@@ -982,7 +1052,7 @@ out:
 	*retmp = top;
 	return (error);
 }
-#endif /*ZERO_COPY_SOCKETS*/
+#endif /* ZERO_COPY_SOCKETS */
 
 #define	SBLOCKWAIT(f)	(((f) & MSG_DONTWAIT) ? 0 : SBL_WAIT)
 
@@ -990,7 +1060,8 @@ int
 sosend_dgram(struct socket *so, struct sockaddr *addr, struct uio *uio,
     struct mbuf *top, struct mbuf *control, int flags, struct thread *td)
 {
-	long space, resid;
+	long space;
+	ssize_t resid;
 	int clen = 0, error, dontroute;
 #ifdef ZERO_COPY_SOCKETS
 	int atomic = sosendallatonce(so) || top;
@@ -1164,7 +1235,8 @@ int
 sosend_generic(struct socket *so, struct sockaddr *addr, struct uio *uio,
     struct mbuf *top, struct mbuf *control, int flags, struct thread *td)
 {
-	long space, resid;
+	long space;
+	ssize_t resid;
 	int clen = 0, error, dontroute;
 	int atomic = sosendallatonce(so) || top;
 
@@ -1463,11 +1535,12 @@ soreceive_generic(struct socket *so, struct sockaddr **psa, struct uio *uio,
     struct mbuf **mp0, struct mbuf **controlp, int *flagsp)
 {
 	struct mbuf *m, **mp;
-	int flags, len, error, offset;
+	int flags, error, offset;
+	ssize_t len;
 	struct protosw *pr = so->so_proto;
 	struct mbuf *nextrecord;
 	int moff, type = 0;
-	int orig_resid = uio->uio_resid;
+	ssize_t orig_resid = uio->uio_resid;
 
 	mp = mp0;
 	if (psa != NULL)
@@ -1920,6 +1993,7 @@ release:
 
 /*
  * Optimized version of soreceive() for stream (TCP) sockets.
+ * XXXAO: (MSG_WAITALL | MSG_PEEK) isn't properly handled.
  */
 int
 soreceive_stream(struct socket *so, struct sockaddr **psa, struct uio *uio,
@@ -1960,20 +2034,9 @@ soreceive_stream(struct socket *so, struct sockaddr **psa, struct uio *uio,
 	}
 	oresid = uio->uio_resid;
 
-	/* We will never ever get anything unless we are connected. */
+	/* We will never ever get anything unless we are or were connected. */
 	if (!(so->so_state & (SS_ISCONNECTED|SS_ISDISCONNECTED))) {
-		/* When disconnecting there may be still some data left. */
-		if (sb->sb_cc > 0)
-			goto deliver;
-		if (!(so->so_state & SS_ISDISCONNECTED))
-			error = ENOTCONN;
-		goto out;
-	}
-
-	/* Socket buffer is empty and we shall not block. */
-	if (sb->sb_cc == 0 &&
-	    ((sb->sb_flags & SS_NBIO) || (flags & (MSG_DONTWAIT|MSG_NBIO)))) {
-		error = EAGAIN;
+		error = ENOTCONN;
 		goto out;
 	}
 
@@ -2000,6 +2063,13 @@ restart:
 			goto out;
 	}
 
+	/* Socket buffer is empty and we shall not block. */
+	if (sb->sb_cc == 0 &&
+	    ((so->so_state & SS_NBIO) || (flags & (MSG_DONTWAIT|MSG_NBIO)))) {
+		error = EAGAIN;
+		goto out;
+	}
+
 	/* Socket buffer got some data that we shall deliver now. */
 	if (sb->sb_cc > 0 && !(flags & MSG_WAITALL) &&
 	    ((sb->sb_flags & SS_NBIO) ||
@@ -2012,7 +2082,7 @@ restart:
 
 	/* On MSG_WAITALL we must wait until all data or error arrives. */
 	if ((flags & MSG_WAITALL) &&
-	    (sb->sb_cc >= uio->uio_resid || sb->sb_cc >= sb->sb_lowat))
+	    (sb->sb_cc >= uio->uio_resid || sb->sb_cc >= sb->sb_hiwat))
 		goto deliver;
 
 	/*
@@ -2040,7 +2110,11 @@ deliver:
 	if (mp0 != NULL) {
 		/* Dequeue as many mbufs as possible. */
 		if (!(flags & MSG_PEEK) && len >= sb->sb_mb->m_len) {
-			for (*mp0 = m = sb->sb_mb;
+			if (*mp0 == NULL)
+				*mp0 = sb->sb_mb;
+			else
+				m_cat(*mp0, sb->sb_mb);
+			for (m = sb->sb_mb;
 			     m != NULL && m->m_len <= len;
 			     m = m->m_next) {
 				len -= m->m_len;
@@ -2048,10 +2122,11 @@ deliver:
 				sbfree(sb, m);
 				n = m;
 			}
+			n->m_next = NULL;
 			sb->sb_mb = m;
+			sb->sb_lastrecord = sb->sb_mb;
 			if (sb->sb_mb == NULL)
 				SB_EMPTY_FIXUP(sb);
-			n->m_next = NULL;
 		}
 		/* Copy the remainder. */
 		if (len > 0) {
@@ -2062,9 +2137,9 @@ deliver:
 			if (m == NULL)
 				len = 0;	/* Don't flush data from sockbuf. */
 			else
-				uio->uio_resid -= m->m_len;
+				uio->uio_resid -= len;
 			if (*mp0 != NULL)
-				n->m_next = m;
+				m_cat(*mp0, m);
 			else
 				*mp0 = m;
 			if (*mp0 == NULL) {
@@ -2128,7 +2203,8 @@ soreceive_dgram(struct socket *so, struct sockaddr **psa, struct uio *uio,
     struct mbuf **mp0, struct mbuf **controlp, int *flagsp)
 {
 	struct mbuf *m, *m2;
-	int flags, len, error;
+	int flags, error;
+	ssize_t len;
 	struct protosw *pr = so->so_proto;
 	struct mbuf *nextrecord;
 
@@ -2334,9 +2410,11 @@ soshutdown(struct socket *so, int how)
 		sorflush(so);
 	if (how != SHUT_RD) {
 		error = (*pr->pr_usrreqs->pru_shutdown)(so);
+		wakeup(&so->so_timeo);
 		CURVNET_RESTORE();
 		return (error);
 	}
+	wakeup(&so->so_timeo);
 	CURVNET_RESTORE();
 	return (0);
 }
@@ -2445,6 +2523,7 @@ sosetopt(struct socket *so, struct sockopt *sopt)
 	struct	linger l;
 	struct	timeval tv;
 	u_long  val;
+	uint32_t val32;
 #ifdef MAC
 	struct mac extmac;
 #endif
@@ -2509,21 +2588,29 @@ sosetopt(struct socket *so, struct sockopt *sopt)
 		case SO_SETFIB:
 			error = sooptcopyin(sopt, &optval, sizeof optval,
 					    sizeof optval);
+			if (error)
+				goto bad;
+
 			if (optval < 0 || optval >= rt_numfibs) {
 				error = EINVAL;
 				goto bad;
 			}
 			if (((so->so_proto->pr_domain->dom_family == PF_INET) ||
 			   (so->so_proto->pr_domain->dom_family == PF_INET6) ||
-			   (so->so_proto->pr_domain->dom_family == PF_ROUTE))) {
+			   (so->so_proto->pr_domain->dom_family == PF_ROUTE)))
 				so->so_fibnum = optval;
-				/* Note: ignore error */
-				if (so->so_proto->pr_ctloutput)
-					(*so->so_proto->pr_ctloutput)(so, sopt);
-			} else {
+			else
 				so->so_fibnum = 0;
-			}
 			break;
+
+		case SO_USER_COOKIE:
+			error = sooptcopyin(sopt, &val32, sizeof val32,
+					    sizeof val32);
+			if (error)
+				goto bad;
+			so->so_user_cookie = val32;
+			break;
+
 		case SO_SNDBUF:
 		case SO_RCVBUF:
 		case SO_SNDLOWAT:
@@ -3289,24 +3376,6 @@ socheckuid(struct socket *so, uid_t uid)
 }
 #endif /* __rtems__ */
 
-static int
-sysctl_somaxconn(SYSCTL_HANDLER_ARGS)
-{
-	int error;
-	int val;
-
-	val = somaxconn;
-	error = sysctl_handle_int(oidp, &val, 0, req);
-	if (error || !req->newptr )
-		return (error);
-
-	if (val < 1 || val > USHRT_MAX)
-		return (EINVAL);
-
-	somaxconn = val;
-	return (0);
-}
-
 /*
  * These functions are used by protocols to notify the socket layer (and its
  * consumers) of state changes in the sockets driven by protocol-side events.