conntrackd: generalize file descriptor infrastructure

This patch generalizes the select-based file descriptor infrastructure
by allowing you to register file descriptors and its callbacks. Instead
of hardcoding the descriptors that needs to be checked.

Now, struct fds_item contains a callback and pointer to data that is
passed to it:

  struct fds_item {
         struct list_head        head;
         int                     fd;
 +       void                    (*cb)(void *data);
 +       void                    *data;
  };

Then, we check which ones are active in the select_main_step() function:

 list_for_each_entry(cur, &STATE(fds)->list, head) {
         if (FD_ISSET(cur->fd, &readfds))
                 cur->cb(cur->data);
 }

And it invoked the corresponding callback.

I had to slightly modify the channel infrastructure to fit it into
the changes.

This modularity is required for the upcoming cthelper support.

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

3 files changed, 13 insertions, 5 deletions

diff --git a/include/channel.h b/include/channel.h
index 9b5fad8..46a354f 100644
--- a/include/channel.h
+++ b/include/channel.h
@@ -35,7 +35,8 @@ struct tcp_channel {
 #define CHANNEL_F_BUFFERED	(1 << 1)
 #define CHANNEL_F_STREAM	(1 << 2)
 #define CHANNEL_F_ERRORS	(1 << 3)
-#define CHANNEL_F_MAX		(1 << 4)
+#define CHANNEL_F_ACCEPT	(1 << 4)
+#define CHANNEL_F_MAX		(1 << 5)
 
 union channel_type_conf {
 	struct mcast_conf mcast;
@@ -52,8 +53,12 @@ struct channel_conf {
 
 struct nlif_handle;
 
+#define CHANNEL_T_DATAGRAM	0
+#define CHANNEL_T_STREAM	1
+
 struct channel_ops {
 	int	headersiz;
+	int	type;
 	void *	(*open)(void *conf);
 	void	(*close)(void *channel);
 	int	(*send)(void *channel, const void *data, int len);
@@ -97,6 +102,8 @@ void channel_stats(struct channel *c, int fd);
 void channel_stats_extended(struct channel *c, int active,
 			    struct nlif_handle *h, int fd);
 
+int channel_type(struct channel *c);
+
 #define MULTICHANNEL_MAX	4
 
 struct multichannel {
@@ -119,6 +126,6 @@ void multichannel_stats_extended(struct multichannel *m,
 int multichannel_get_ifindex(struct multichannel *m, int i);
 int multichannel_get_current_ifindex(struct multichannel *m);
 void multichannel_set_current_channel(struct multichannel *m, int i);
-void multichannel_change_current_channel(struct multichannel *m, int i);
+void multichannel_change_current_channel(struct multichannel *m, struct channel *c);
 
 #endif /* _CHANNEL_H_ */
diff --git a/include/conntrackd.h b/include/conntrackd.h
index 9359dfa..0e203e7 100644
--- a/include/conntrackd.h
+++ b/include/conntrackd.h
@@ -264,7 +264,6 @@ extern struct ct_general_state st;
 struct ct_mode {
 	struct internal_handler *internal;
 	int (*init)(void);
-	void (*run)(fd_set *readfds);
 	int (*local)(int fd, int type, void *data);
 	void (*kill)(void);
 };
@@ -278,7 +277,7 @@ extern struct ct_mode stats_mode;
 /* These live in run.c */
 void killer(int foo);
 int init(void);
-void run(void);
+void select_main_loop(void);
 
 /* from read_config_yy.c */
 int
diff --git a/include/fds.h b/include/fds.h
index f3728d7..ed0c8be 100644
--- a/include/fds.h
+++ b/include/fds.h
@@ -12,11 +12,13 @@ struct fds {
 struct fds_item {
 	struct list_head        head;
 	int                     fd;
+	void			(*cb)(void *data);
+	void			*data;
 };
 
 struct fds *create_fds(void);
 void destroy_fds(struct fds *);
-int register_fd(int fd, struct fds *fds);
+int register_fd(int fd, void (*cb)(void *data), void *data, struct fds *fds);
 int unregister_fd(int fd, struct fds *fds);
 
 #endif