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>

1 files changed, 3 insertions, 1 deletions

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