accept pacing ldpd way. Since this daemon has multiple listening fds

we add them all to a accept queue that does the pacing with the
accept_pause() and accept_unpause() calls.
With and OK deraadt@

8 files changed, 180 insertions, 31 deletions

diff --git a/usr.sbin/ldpd/Makefile b/usr.sbin/ldpd/Makefile
index f03dfc97829..792177b68fd 100644
--- a/usr.sbin/ldpd/Makefile
+++ b/usr.sbin/ldpd/Makefile
@@ -1,7 +1,7 @@
-#	$OpenBSD: Makefile,v 1.3 2010/05/26 16:44:32 nicm Exp $
+#	$OpenBSD: Makefile,v 1.4 2012/04/12 17:33:43 claudio Exp $
 
 PROG=	ldpd
-SRCS=	address.c control.c hello.c init.c interface.c \
+SRCS=	accept.c address.c control.c hello.c init.c interface.c \
 	keepalive.c kroute.c labelmapping.c lde.c lde_lib.c ldpd.c ldpe.c \
 	log.c neighbor.c notification.c packet.c parse.y printconf.c
 
diff --git a/usr.sbin/ldpd/accept.c b/usr.sbin/ldpd/accept.c
new file mode 100644
index 00000000000..4f1a585f83a
--- /dev/null
+++ b/usr.sbin/ldpd/accept.c
@@ -0,0 +1,137 @@
+/*	$OpenBSD: accept.c,v 1.1 2012/04/12 17:33:43 claudio Exp $ */
+
+/*
+ * Copyright (c) 2012 Claudio Jeker <claudio@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/queue.h>
+#include <sys/time.h>
+#include <event.h>
+#include <stdlib.h>
+
+#include "ldpd.h"
+#include "ldpe.h"
+#include "log.h"
+
+struct accept_ev {
+	LIST_ENTRY(accept_ev)	 entry;
+	struct event		 ev;
+	void			(*accept_cb)(int, short, void *);
+	void			*arg;
+	int			 fd;
+};
+
+struct {
+	LIST_HEAD(, accept_ev)	queue;
+	struct event		evt;
+} accept_queue;
+
+void	accept_arm(void);
+void	accept_unarm(void);
+void	accept_cb(int, short, void *);
+void	accept_timeout(int, short, void *);
+
+void
+accept_init(void)
+{
+	LIST_INIT(&accept_queue.queue);
+	evtimer_set(&accept_queue.evt, accept_timeout, NULL);
+}
+
+int
+accept_add(int fd, void (*cb)(int, short, void *), void *arg)
+{
+	struct accept_ev	*av;
+
+	if ((av = calloc(1, sizeof(*av))) == NULL)
+		return -1;
+	av->fd = fd;
+	av->accept_cb = cb;
+	av->arg = arg;
+	LIST_INSERT_HEAD(&accept_queue.queue, av, entry);
+
+	event_set(&av->ev, av->fd, EV_READ, accept_cb, av);
+	event_add(&av->ev, NULL);
+
+	log_debug("accept_add: accepting on fd %d", fd);
+
+	return (0);
+}
+
+void
+accept_del(int fd)
+{
+	struct accept_ev	*av;
+
+	LIST_FOREACH(av, &accept_queue.queue, entry)
+		if (av->fd == fd) {
+			log_debug("accept_del: %i removed from queue", fd);
+			event_del(&av->ev);
+			LIST_REMOVE(av, entry);
+			free(av);
+			return;
+		}
+}
+
+void
+accept_pause(void)
+{
+	struct timeval evtpause = { 1, 0 };
+
+	log_debug("accept_pause");
+	accept_unarm();
+	evtimer_add(&accept_queue.evt, &evtpause);
+}
+
+void
+accept_unpause(void)
+{
+	if (evtimer_pending(&accept_queue.evt, NULL)) {
+		log_debug("accept_unpause");
+		evtimer_del(&accept_queue.evt);
+		accept_arm();
+	}
+}
+
+void
+accept_arm(void)
+{
+	struct accept_ev	*av;
+	LIST_FOREACH(av, &accept_queue.queue, entry)
+		event_add(&av->ev, NULL);
+}
+
+void
+accept_unarm(void)
+{
+	struct accept_ev	*av;
+	LIST_FOREACH(av, &accept_queue.queue, entry)
+		event_del(&av->ev);
+}
+
+void
+accept_cb(int fd, short event, void *arg)
+{
+	struct accept_ev	*av = arg;
+	event_add(&av->ev, NULL);
+	av->accept_cb(fd, event, av->arg);
+}
+
+void
+accept_timeout(int fd, short event, void *bula)
+{
+	log_debug("accept_timeout");
+	accept_arm();
+}
diff --git a/usr.sbin/ldpd/control.c b/usr.sbin/ldpd/control.c
index 42908960955..5a14a802977 100644
--- a/usr.sbin/ldpd/control.c
+++ b/usr.sbin/ldpd/control.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: control.c,v 1.9 2010/09/01 13:54:54 claudio Exp $ */
+/*	$OpenBSD: control.c,v 1.10 2012/04/12 17:33:43 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -38,6 +38,8 @@ struct ctl_conn	*control_connbyfd(int);
 struct ctl_conn	*control_connbypid(pid_t);
 void		 control_close(int);
 
+int control_fd;
+
 int
 control_init(void)
 {
@@ -78,7 +80,7 @@ control_init(void)
 	}
 
 	session_socket_blockmode(fd, BM_NONBLOCK);
-	control_state.fd = fd;
+	control_fd = fd;
 
 	return (0);
 }
@@ -87,16 +89,12 @@ int
 control_listen(void)
 {
 
-	if (listen(control_state.fd, CONTROL_BACKLOG) == -1) {
+	if (listen(control_fd, CONTROL_BACKLOG) == -1) {
 		log_warn("control_listen: listen");
 		return (-1);
 	}
 
-	event_set(&control_state.ev, control_state.fd, EV_READ | EV_PERSIST,
-	    control_accept, NULL);
-	event_add(&control_state.ev, NULL);
-
-	return (0);
+	return (accept_add(control_fd, control_accept, NULL));
 }
 
 void
@@ -115,9 +113,14 @@ control_accept(int listenfd, short event, void *bula)
 	struct ctl_conn		*c;
 
 	len = sizeof(sun);
-	if ((connfd = accept(listenfd,
-	    (struct sockaddr *)&sun, &len)) == -1) {
-		if (errno != EWOULDBLOCK && errno != EINTR)
+	if ((connfd = accept(listenfd, (struct sockaddr *)&sun, &len)) == -1) {
+		/*
+		 * Pause accept if we are out of file descriptors, or
+		 * libevent will haunt us here too.
+		 */
+		if (errno == ENFILE || errno == EMFILE)
+			accept_pause();
+		else if (errno != EWOULDBLOCK && errno != EINTR)
 			log_warn("control_accept: accept");
 		return;
 	}
@@ -180,6 +183,7 @@ control_close(int fd)
 	event_del(&c->iev.ev);
 	close(c->iev.ibuf.fd);
 	free(c);
+	accept_unpause();
 }
 
 /* ARGSUSED */
diff --git a/usr.sbin/ldpd/control.h b/usr.sbin/ldpd/control.h
index 7468b636500..5bd57c26c00 100644
--- a/usr.sbin/ldpd/control.h
+++ b/usr.sbin/ldpd/control.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: control.h,v 1.3 2010/04/15 15:04:23 claudio Exp $ */
+/*	$OpenBSD: control.h,v 1.4 2012/04/12 17:33:43 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -23,11 +23,6 @@
 #include <sys/time.h>
 #include <event.h>
 
-struct {
-	struct event	ev;
-	int		fd;
-} control_state;
-
 struct ctl_conn {
 	TAILQ_ENTRY(ctl_conn)	entry;
 	struct imsgev		iev;
diff --git a/usr.sbin/ldpd/ldpd.h b/usr.sbin/ldpd/ldpd.h
index e6c9ed91895..6633b603291 100644
--- a/usr.sbin/ldpd/ldpd.h
+++ b/usr.sbin/ldpd/ldpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ldpd.h,v 1.28 2011/01/10 12:28:25 claudio Exp $ */
+/*	$OpenBSD: ldpd.h,v 1.29 2012/04/12 17:33:43 claudio Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -246,7 +246,7 @@ enum blockmodes {
 #define	MODE_ADV_UNSOLICITED	0x20
 
 struct ldpd_conf {
-	struct event		disc_ev, sess_ev;
+	struct event		disc_ev;
 	struct in_addr		rtr_id;
 	LIST_HEAD(, iface)	iface_list;
 
diff --git a/usr.sbin/ldpd/ldpe.c b/usr.sbin/ldpd/ldpe.c
index a65d1bef376..f3521502f1f 100644
--- a/usr.sbin/ldpd/ldpe.c
+++ b/usr.sbin/ldpd/ldpe.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ldpe.c,v 1.15 2011/07/04 04:34:14 claudio Exp $ */
+/*	$OpenBSD: ldpe.c,v 1.16 2012/04/12 17:33:43 claudio Exp $ */
 
 /*
  * Copyright (c) 2005 Claudio Jeker <claudio@openbsd.org>
@@ -160,6 +160,7 @@ ldpe(struct ldpd_conf *xconf, int pipe_parent2ldpe[2], int pipe_ldpe2lde[2],
 		fatal("can't drop privileges");
 
 	event_init();
+	accept_init();
 
 	/* setup signal handler */
 	signal_set(&ev_sigint, SIGINT, ldpe_sig_handler, NULL);
@@ -198,10 +199,7 @@ ldpe(struct ldpd_conf *xconf, int pipe_parent2ldpe[2], int pipe_ldpe2lde[2],
 	    EV_READ|EV_PERSIST, disc_recv_packet, leconf);
 	event_add(&leconf->disc_ev, NULL);
 
-	event_set(&leconf->sess_ev, leconf->ldp_session_socket,
-	    EV_READ|EV_PERSIST, session_accept, leconf);
-	event_add(&leconf->sess_ev, NULL);
-
+	accept_add(leconf->ldp_session_socket, session_accept, leconf);
 	/* listen on ldpd control socket */
 	TAILQ_INIT(&ctl_conns);
 	control_listen();
diff --git a/usr.sbin/ldpd/ldpe.h b/usr.sbin/ldpd/ldpe.h
index 46fd0496ee2..1a6f2674a64 100644
--- a/usr.sbin/ldpd/ldpe.h
+++ b/usr.sbin/ldpd/ldpe.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ldpe.h,v 1.15 2011/03/12 01:57:13 claudio Exp $ */
+/*	$OpenBSD: ldpe.h,v 1.16 2012/04/12 17:33:43 claudio Exp $ */
 
 /*
  * Copyright (c) 2004, 2005, 2008 Esben Norby <norby@openbsd.org>
@@ -73,6 +73,13 @@ struct nbr {
 
 };
 
+/* accept.c */
+void	accept_init(void);
+int	accept_add(int, void (*)(int, short, void *), void *);
+void	accept_del(int);
+void	accept_pause(void);
+void	accept_unpause(void);
+
 /* hello.c */
 int	 send_hello(struct iface *);
 void	 recv_hello(struct iface *,  struct in_addr, char *, u_int16_t);
diff --git a/usr.sbin/ldpd/packet.c b/usr.sbin/ldpd/packet.c
index b23739c6d90..5a5880d162f 100644
--- a/usr.sbin/ldpd/packet.c
+++ b/usr.sbin/ldpd/packet.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: packet.c,v 1.15 2011/03/12 01:52:04 claudio Exp $ */
+/*	$OpenBSD: packet.c,v 1.16 2012/04/12 17:33:43 claudio Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -257,13 +257,20 @@ session_accept(int fd, short event, void *bula)
 	int			 newfd;
 	socklen_t		 len = sizeof(src);
 
-	if (event != EV_READ)
+	if (!(event & EV_READ))
 		return;
 
 	newfd = accept(fd, (struct sockaddr *)&src, &len);
 	if (newfd == -1) {
-		log_debug("sess_recv_packet: accept error: %s",
-		    strerror(errno));
+		/*
+		 * Pause accept if we are out of file descriptors, or
+		 * libevent will haunt us here too.
+		 */
+		if (errno == ENFILE || errno == EMFILE) {
+			accept_pause();
+		} else if (errno != EWOULDBLOCK && errno != EINTR)
+			log_debug("sess_recv_packet: accept error: %s",
+			    strerror(errno));
 		return;
 	}
 
@@ -454,6 +461,7 @@ session_close(struct nbr *nbr)
 		evtimer_del(&nbr->keepalive_timeout);
 
 	close(nbr->fd);
+	accept_unpause();
 }
 
 ssize_t