conf, tcp: Periodic detection of bound ports for pasta port forwarding

Detecting bound ports at start-up time isn't terribly useful: do this
periodically instead, if configured.

This is only implemented for TCP at the moment, UDP is somewhat more
complicated: leave a TODO there.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/util.c b/util.c
index 285c0b6..3cf3a82 100644
--- a/util.c
+++ b/util.c
@@ -266,8 +266,9 @@ int bitmap_isset(uint8_t *map, int bit)
  * procfs_scan_listen() - Set bits for listening TCP or UDP sockets from procfs
  * @name:	Corresponding name of file under /proc/net/
  * @map:	Bitmap where numbers of ports in listening state will be set
+ * @exclude:	Bitmap of ports to exclude from setting (and clear)
  */
-void procfs_scan_listen(char *name, uint8_t *map)
+void procfs_scan_listen(char *name, uint8_t *map, uint8_t *exclude)
 {
 	char line[200], path[PATH_MAX];
 	unsigned long port;
@@ -288,7 +289,10 @@ void procfs_scan_listen(char *name, uint8_t *map)
 		    (strstr(name, "udp") && state != 0x07))
 			continue;
 
-		bitmap_set(map, port);
+		if (bitmap_isset(exclude, port))
+			bitmap_clear(map, port);
+		else
+			bitmap_set(map, port);
 	}
 
 	fclose(fp);