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@

1 files changed, 137 insertions, 0 deletions

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();
+}