sync: unify tx_list and tx_queue into one single tx_queue

This patch unifies the tx_list and the tx_queue to have only one
transmission queue. Since the tx_list hold state objects and
tx_queue control messages, I have introduced a queue node type
that can be used to differenciate the kind of information that
the node stores: object or control message.

This patch also reworks the existing queue class to include a
file descriptor that can be used to know if there are new data
added to the queue (see QUEUE_F_EVFD flag).

In this change, I have also modified the current evfd to make the
file descriptor to make read operations non-blocking. Moreover,
it keeps a counter that is used to know how many messages are
inserted in the queue.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

3 files changed, 43 insertions, 15 deletions

diff --git a/include/conntrackd.h b/include/conntrackd.h
index 67397b8..8cb520d 100644
--- a/include/conntrackd.h
+++ b/include/conntrackd.h
@@ -150,7 +150,6 @@ struct ct_sync_state {
 
 	struct mcast_sock *mcast_server;  /* multicast socket: incoming */
 	struct mcast_sock *mcast_client;  /* multicast socket: outgoing  */
-	struct evfd *evfd;		  /* event fd */
 
 	struct sync_mode *sync;		/* sync mode */
 
diff --git a/include/queue.h b/include/queue.h
index 5a9cf39..ef56323 100644
--- a/include/queue.h
+++ b/include/queue.h
@@ -1,28 +1,53 @@
 #ifndef _QUEUE_H_
 #define _QUEUE_H_
 
+#include <stdint.h>
 #include "linux_list.h"
 
-struct queue {
-	size_t max_size;
-	size_t cur_size;
-	unsigned int num_elems;
-	struct list_head head;
+struct queue_node {
+	struct list_head	head;
+	uint32_t		type;
+	struct queue		*owner;
+	size_t 			size;
 };
 
-struct queue_node {
-	struct list_head head;
-	size_t size;
-	char data[0];
+enum {
+	Q_ELEM_OBJ = 0,
+	Q_ELEM_CTL = 1
+};
+
+void queue_node_init(struct queue_node *n, int type);
+void *queue_node_data(struct queue_node *n);
+
+struct queue_object {
+	struct queue_node	qnode;
+	char			data[0];
 };
 
-struct queue *queue_create(size_t max_size);
+struct queue_object *queue_object_new(int type, size_t size);
+void queue_object_free(struct queue_object *obj);
+
+struct evfd;
+
+struct queue {
+	unsigned int		max_elems;
+	unsigned int		num_elems;
+	uint32_t		flags;
+	struct list_head	head;
+	struct evfd		*evfd;
+};
+
+#define QUEUE_F_EVFD (1U << 0)
+
+struct queue *queue_create(int max_objects, unsigned int flags);
 void queue_destroy(struct queue *b);
 unsigned int queue_len(const struct queue *b);
-int queue_add(struct queue *b, const void *data, size_t size);
-void queue_del(struct queue *b, void *data);
+int queue_add(struct queue *b, struct queue_node *n);
+int queue_del(struct queue_node *n);
+int queue_in(struct queue *b, struct queue_node *n);
 void queue_iterate(struct queue *b,
 		   const void *data,
-		   int (*iterate)(void *data1, const void *data2));
+		   int (*iterate)(struct queue_node *n, const void *data2));
+int queue_get_eventfd(struct queue *b);
 
 #endif
diff --git a/include/sync.h b/include/sync.h
index 60c9fae..9a9540c 100644
--- a/include/sync.h
+++ b/include/sync.h
@@ -1,8 +1,11 @@
 #ifndef _SYNC_HOOKS_H_
 #define _SYNC_HOOKS_H_
 
+#include <sys/select.h>
+
 struct nethdr;
 struct cache_object;
+struct fds;
 
 struct sync_mode {
 	int internal_cache_flags;
@@ -15,7 +18,8 @@ struct sync_mode {
 	int  (*local)(int fd, int type, void *data);
 	int  (*recv)(const struct nethdr *net);
 	void (*send)(struct nethdr *net, struct cache_object *obj);
-	void (*run)(void);
+	void (*run)(fd_set *readfds);
+	int (*register_fds)(struct fds *fds);
 };
 
 extern struct sync_mode sync_alarm;