compose the file descriptor set at initialization stage to save some cycles

9 files changed, 120 insertions, 21 deletions

diff --git a/ChangeLog b/ChangeLog
index aa485a1..411118e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -47,6 +47,7 @@ o remove unix socket file on exit
 o use umask() to set up file permissions
 o add support for NAT sequence adjustment (requires Linux kernel >= 2.6.25)
 o remove TODO file from release tarballs
+o compose the file descriptor set at initialization stage to save some cycles
 
 Max Kellermann <max@duempel.org>:
 
diff --git a/include/Makefile.am b/include/Makefile.am
index d7f27a9..92ebbcc 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -3,5 +3,5 @@ noinst_HEADERS = alarm.h jhash.h slist.h cache.h linux_list.h linux_rbtree.h \
 		 sync.h conntrackd.h local.h us-conntrack.h \
 		 debug.h log.h hash.h mcast.h conntrack.h \
 		 state_helper.h network.h ignore.h queue.h \
-		 traffic_stats.h netlink.h
+		 traffic_stats.h netlink.h fds.h
 
diff --git a/include/conntrackd.h b/include/conntrackd.h
index 47898e2..69c1303 100644
--- a/include/conntrackd.h
+++ b/include/conntrackd.h
@@ -105,6 +105,8 @@ struct ct_general_state {
 	struct nfct_handle		*event;         /* event handler */
 	struct nfct_handle		*dump;		/* dump handler */
 
+	struct fds			*fds;
+
 	/* statistics */
 	uint64_t			malformed;
 	uint64_t 			bytes[NFCT_DIR_MAX];
@@ -151,7 +153,7 @@ extern struct ct_general_state st;
 
 struct ct_mode {
 	int (*init)(void);
-	int (*add_fds_to_set)(fd_set *readfds);
+	int (*register_fds)(struct fds *fds);
 	void (*run)(fd_set *readfds);
 	int (*local)(int fd, int type, void *data);
 	void (*kill)(void);
diff --git a/include/fds.h b/include/fds.h
new file mode 100644
index 0000000..cc213fe
--- /dev/null
+++ b/include/fds.h
@@ -0,0 +1,16 @@
+#ifndef _FDS_H_
+#define _FDS_H_
+
+struct fds {
+	int	maxfd;
+	int	fd_array_len;
+	int	fd_array_cur;
+	int	*fd_array;
+	fd_set	readfds;
+};
+
+struct fds *create_fds(void);
+void destroy_fds(struct fds *);
+int register_fd(int fd, struct fds *fds);
+
+#endif
diff --git a/src/Makefile.am b/src/Makefile.am
index 7274a14..494da4f 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -12,7 +12,7 @@ conntrack_LDFLAGS = $(all_libraries) @LIBNETFILTER_CONNTRACK_LIBS@
 
 conntrackd_SOURCES = alarm.c main.c run.c hash.c queue.c rbtree.c \
 		    local.c log.c mcast.c netlink.c \
-		    ignore_pool.c \
+		    ignore_pool.c fds.c \
 		    cache.c cache_iterators.c \
 		    cache_lifetime.c cache_timer.c cache_wt.c \
 		    sync-mode.c sync-alarm.c sync-ftfw.c \
diff --git a/src/fds.c b/src/fds.c
new file mode 100644
index 0000000..908f048
--- /dev/null
+++ b/src/fds.c
@@ -0,0 +1,74 @@
+/*
+ * (C) 2006-2008 by Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <stdlib.h>
+#include <string.h>
+#include "fds.h"
+
+/* we don't handle that many descriptors so eight is just fine */
+#define FDS_ARRAY_LEN 8
+#define FDS_ARRAY_SIZE (sizeof(int) * FDS_ARRAY_LEN)
+
+struct fds *create_fds(void)
+{
+	struct fds *fds;
+
+	fds = (struct fds *) malloc(sizeof(struct fds));
+	if (fds == NULL)
+		return NULL;
+
+	memset(fds, 0, sizeof(struct fds));
+
+	fds->fd_array = (int *) malloc(FDS_ARRAY_SIZE);
+	if (fds->fd_array == NULL) {
+		free(fds);
+		return NULL;
+	}
+
+	memset(fds->fd_array, 0, FDS_ARRAY_SIZE);
+	fds->fd_array_len = FDS_ARRAY_LEN;
+
+	return fds;
+}
+
+void destroy_fds(struct fds *fds)
+{
+	free(fds->fd_array);
+	free(fds);
+}
+
+int register_fd(int fd, struct fds *fds)
+{
+	FD_SET(fd, &fds->readfds);
+
+	if (fd > fds->maxfd)
+		fds->maxfd = fd;
+
+	if (fds->fd_array_cur >= fds->fd_array_len) {
+		fds->fd_array_len += FDS_ARRAY_LEN;
+		fds->fd_array = realloc(fds->fd_array,
+					fds->fd_array_len * sizeof(int));
+		if (fds->fd_array == NULL) {
+			fds->fd_array_len -= FDS_ARRAY_LEN;
+			return -1;
+		}
+	}
+
+	fds->fd_array[fds->fd_array_cur++] = fd;
+
+	return 0;
+}
diff --git a/src/run.c b/src/run.c
index 6cf259d..b259f2e 100644
--- a/src/run.c
+++ b/src/run.c
@@ -23,6 +23,7 @@
 #include "ignore.h"
 #include "log.h"
 #include "alarm.h"
+#include "fds.h"
 
 #include <errno.h>
 #include <signal.h>
@@ -128,6 +129,21 @@ init(void)
 		return -1;
 	}
 
+	STATE(fds) = create_fds();
+	if (STATE(fds) == NULL) {
+		dlog(LOG_ERR, "can't create file descriptor pool");
+		return -1;
+	}
+
+	register_fd(STATE(local).fd, STATE(fds));
+	register_fd(nfct_fd(STATE(event)), STATE(fds));
+
+	if (STATE(mode)->register_fds &&
+	    STATE(mode)->register_fds(STATE(fds)) == -1) {
+		dlog(LOG_ERR, "fds registration failed");
+		return -1;
+	}
+
 	/* Signals handling */
 	sigemptyset(&STATE(block));
 	sigaddset(&STATE(block), SIGTERM);
@@ -154,19 +170,10 @@ init(void)
 
 static void __run(struct timeval *next_alarm)
 {
-	int max, ret;
-	fd_set readfds;
-
-	FD_ZERO(&readfds);
-	FD_SET(STATE(local).fd, &readfds);
-	FD_SET(nfct_fd(STATE(event)), &readfds);
-
-	max = MAX(STATE(local).fd, nfct_fd(STATE(event)));
-
-	if (STATE(mode)->add_fds_to_set)
-		max = MAX(max, STATE(mode)->add_fds_to_set(&readfds));
+	int ret;
+	fd_set readfds = STATE(fds)->readfds;
 
-	ret = select(max+1, &readfds, NULL, NULL, next_alarm);
+	ret = select(STATE(fds)->maxfd + 1, &readfds, NULL, NULL, next_alarm);
 	if (ret == -1) {
 		/* interrupted syscall, retry */
 		if (errno == EINTR)
diff --git a/src/stats-mode.c b/src/stats-mode.c
index b6ae2bd..42fa35a 100644
--- a/src/stats-mode.c
+++ b/src/stats-mode.c
@@ -181,7 +181,7 @@ static int event_destroy_stats(struct nf_conntrack *ct)
 
 struct ct_mode stats_mode = {
 	.init 			= init_stats,
-	.add_fds_to_set 	= NULL,
+	.register_fds 		= NULL,
 	.run			= NULL,
 	.local			= local_handler_stats,
 	.kill			= kill_stats,
diff --git a/src/sync-mode.c b/src/sync-mode.c
index a81309f..79afcdf 100644
--- a/src/sync-mode.c
+++ b/src/sync-mode.c
@@ -25,6 +25,7 @@
 #include "conntrackd.h"
 #include "us-conntrack.h"
 #include "network.h"
+#include "fds.h"
 #include "debug.h"
 
 #include <errno.h>
@@ -202,11 +203,9 @@ static int init_sync(void)
 	return 0;
 }
 
-static int add_fds_to_set_sync(fd_set *readfds) 
+static int register_fds_sync(struct fds *fds) 
 {
-	FD_SET(STATE_SYNC(mcast_server->fd), readfds);
-
-	return STATE_SYNC(mcast_server->fd);
+	return register_fd(STATE_SYNC(mcast_server->fd), fds);
 }
 
 static void run_sync(fd_set *readfds)
@@ -500,7 +499,7 @@ static int event_destroy_sync(struct nf_conntrack *ct)
 
 struct ct_mode sync_mode = {
 	.init 			= init_sync,
-	.add_fds_to_set 	= add_fds_to_set_sync,
+	.register_fds		= register_fds_sync,
 	.run			= run_sync,
 	.local			= local_handler_sync,
 	.kill			= kill_sync,