kernel.git/net/l2tp/l2tp_core.c, branch linux-5.9.y

l2tp: tweak exports for l2tp_recv_common and l2tp_ioctl

2020-07-30T23:45:31Z

All of the l2tp subsystem's exported symbols are exported using EXPORT_SYMBOL_GPL, except for l2tp_recv_common and l2tp_ioctl. These functions alone are not useful without the rest of the l2tp infrastructure, so there's no practical benefit to these symbols using a different export policy. Change these exports to use EXPORT_SYMBOL_GPL for consistency with the rest of l2tp. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller

l2tp: remove build_header callback in struct l2tp_session

2020-07-30T23:45:31Z

The structure of an L2TP data packet header varies depending on the version of the L2TP protocol being used. struct l2tp_session used to have a build_header callback to abstract this difference away. It's clearer to simply choose the correct function to use when building the data packet (and we save on the function pointer in the session structure). This approach does mean dereferencing the parent tunnel structure in order to determine the tunnel version, but we're doing that in the transmit path in any case. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller

l2tp: return void from l2tp_session_delete

2020-07-30T23:45:31Z

l2tp_session_delete is used to schedule a session instance for deletion. The function itself always returns zero, and none of its direct callers check its return value, so have the function return void. This change de-facto changes the l2tp netlink session_delete callback prototype since all pseudowires currently use l2tp_session_delete for their implementation of that operation. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller

l2tp: don't export tunnel and session free functions

2020-07-30T23:45:31Z

Tunnel and session instances are reference counted, and shouldn't be directly freed by pseudowire code. Rather than exporting l2tp_tunnel_free and l2tp_session_free, make them private to l2tp_core.c, and export the refcount functions instead. In order to do this, the refcount functions cannot be declared as inline. Since the codepaths which take and drop tunnel and session references are not directly in the datapath this shouldn't cause performance issues. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller

l2tp: don't export __l2tp_session_unhash

2020-07-30T23:45:31Z

When __l2tp_session_unhash was first added it was used outside of l2tp_core.c, but that's no longer the case. As such, there's no longer a need to export the function. Make it private inside l2tp_core.c, and relocate it to avoid having to declare the function prototype in l2tp_core.h. Since the function is no longer used outside l2tp_core.c, remove the "__" prefix since we don't need to indicate anything special about its expected use to callers. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller

l2tp: WARN_ON rather than BUG_ON in l2tp_session_free

2020-07-25T00:19:14Z

l2tp_session_free called BUG_ON if the tunnel magic feather value wasn't correct. The intent of this was to catch lifetime bugs; for example early tunnel free due to incorrect use of reference counts. Since the tunnel magic feather being wrong indicates either early free or structure corruption, we can avoid doing more damage by simply leaving the tunnel structure alone. If the tunnel refcount isn't dropped when it should be, the tunnel instance will remain in the kernel, resulting in the tunnel structure and socket leaking. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller

l2tp: remove BUG_ON refcount value in l2tp_session_free

2020-07-25T00:19:14Z

l2tp_session_free is only called by l2tp_session_dec_refcount when the reference count reaches zero, so it's of limited value to validate the reference count value in l2tp_session_free itself. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller

l2tp: WARN_ON rather than BUG_ON in l2tp_session_queue_purge

2020-07-25T00:19:14Z

l2tp_session_queue_purge is used during session shutdown to drop any skbs queued for reordering purposes according to L2TP dataplane rules. The BUG_ON in this function checks the session magic feather in an attempt to catch lifetime bugs. Rather than crashing the kernel with a BUG_ON, we can simply WARN_ON and refuse to do anything more -- in the worst case this could result in a leak. However this is highly unlikely given that the session purge only occurs from codepaths which have obtained the session by means of a lookup via. the parent tunnel and which check the session "dead" flag to protect against shutdown races. While we're here, have l2tp_session_queue_purge return void rather than an integer, since neither of the callsites checked the return value. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller

l2tp: remove BUG_ON in l2tp_tunnel_closeall

2020-07-25T00:19:14Z

l2tp_tunnel_closeall is only called from l2tp_core.c, and it's easy to statically analyse the code path calling it to validate that it should never be passed a NULL tunnel pointer. Having a BUG_ON checking the tunnel pointer triggers a checkpatch warning. Since the BUG_ON is of no value, remove it to avoid the warning. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller

l2tp: remove BUG_ON in l2tp_session_queue_purge

2020-07-25T00:19:14Z

l2tp_session_queue_purge is only called from l2tp_core.c, and it's easy to statically analyse the code paths calling it to validate that it should never be passed a NULL session pointer. Having a BUG_ON checking the session pointer triggers a checkpatch warning. Since the BUG_ON is of no value, remove it to avoid the warning. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller