Currently get_bound_ports() takes a parameter to determine if it scans for
UDP or TCP bound ports, but in fact there's almost nothing in common
between those two paths. The parameter appears primarily to have been
a convenience for when we needed to invoke this function via NS_CALL().
Now that we don't need that, split it into separate TCP and UDP versions.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
When we want to scan for bound ports in the namespace we use NS_CALL() to
run get_bound_ports() in the namespace. However, the only thing it
actually needed to be in the namespace for was to open the /proc/net file
it was scanning. Since we now always pre-open those, we no longer need
to switch to the namespace for the actual get_bound_ports() calls.
That in turn means that tcp_port_detect() doesn't need to run in the ns
either, and we can just replace it with inline calls to get_bound_ports().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
procfs_scan_listen() can either use an already opened fd for a /proc/net
file, or it will open it. So, effectively it will open the file on the
first call, then re-use the fd in subsequent calls. However, it's not
possible to open the /proc/net files after we isolate our filesystem in
isolate_prefork(). That means that for each /proc/net file we must call
procfs_scan_listen() at least once before isolate_prefork(), or it won't
work afterwards.
That happens to be the case, but it's a pretty fragile requirement. To
make this more robust, instead always pre-open the /proc files we will need
in get_bounds_port_init() and have procfs_scan_listen() just use those.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
procfs_scan_listen() does some slightly clunky logic to deduce the fd it
wants to use, the path it wants to open and the state it's looking for
based on parameters for protocol, IP version and whether we're in the
namespace.
However, the caller already has to make choices based on similar parameters
so it can just pass in the things that procfs_scan_listen() needs directly.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
The implementation of scanning /proc files to do automatic port forwarding
is a bit awkwardly split between procfs_scan_listen() in util.c,
get_bound_ports() and related functions in conf.c and the initial setup
code in conf().
Consolidate all of this into port_fwd.h, which already has some related
definitions, and a new port_fwd.c.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
