kernel/net/l2tp/l2tp_debugfs.c, branch linux-5.1.y

l2tp: ignore L2TP_ATTR_MTU

2018-08-03T17:03:57Z

This attribute's handling is broken. It can only be used when creating Ethernet pseudo-wires, in which case its value can be used as the initial MTU for the l2tpeth device. However, when handling update requests, L2TP_ATTR_MTU only modifies session->mtu. This value is never propagated to the l2tpeth device. Dump requests also return the value of session->mtu, which is not synchronised anymore with the device MTU. The same problem occurs if the device MTU is properly updated using the generic IFLA_MTU attribute. In this case, session->mtu is not updated, and L2TP_ATTR_MTU will report an invalid value again when dumping the session. It does not seem worthwhile to complexify l2tp_eth.c to synchronise session->mtu with the device MTU. Even the ip-l2tp manpage advises to use 'ip link' to initialise the MTU of l2tpeth devices (iproute2 does not handle L2TP_ATTR_MTU at all anyway). So let's just ignore it entirely. Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

l2tp: drop ->mru from struct l2tp_session

2018-07-27T20:34:53Z

This field is not used. Treat PPPIOC*MRU the same way as PPPIOC*FLAGS: "get" requests return 0, while "set" requests vadidate the user supplied pointer but discard its value. Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

l2tp: ignore L2TP_ATTR_DATA_SEQ netlink attribute

2018-07-27T20:34:53Z

The value of this attribute is never used. Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

l2tp: remove .show from struct l2tp_tunnel

2018-06-26T13:55:51Z

This callback has never been implemented. Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

l2tp: consistent reference counting in procfs and debufs

2018-04-27T15:06:35Z

The 'pppol2tp' procfs and 'l2tp/tunnels' debugfs files handle reference counting of sessions differently than for tunnels. For consistency, use the same mechanism for handling both sessions and tunnels. That is, drop the reference on the previous session just before looking up the next one (rather than in .show()). If necessary (if dump stops before *_next_session() returns NULL), drop the last reference in .stop(). Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

l2tp: fix {pppol2tp, l2tp_dfs}_seq_stop() in case of seq_file overflow

2018-04-22T18:46:35Z

Commit 0e0c3fee3a59 ("l2tp: hold reference on tunnels printed in pppol2tp proc file") assumed that if pppol2tp_seq_stop() was called with non-NULL private data (the 'v' pointer), then pppol2tp_seq_start() would not be called again. It turns out that this isn't guaranteed, and overflowing the seq_file's buffer in pppol2tp_seq_show() is a way to get into this situation. Therefore, pppol2tp_seq_stop() needs to reset pd->tunnel, so that pppol2tp_seq_start() won't drop a reference again if it gets called. We also have to clear pd->session, because the rest of the code expects a non-NULL tunnel when pd->session is set. The l2tp_debugfs module has the same issue. Fix it in the same way. Fixes: 0e0c3fee3a59 ("l2tp: hold reference on tunnels printed in pppol2tp proc file") Fixes: f726214d9b23 ("l2tp: hold reference on tunnels printed in l2tp/tunnels debugfs file") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

l2tp: hold reference on tunnels printed in l2tp/tunnels debugfs file

2018-04-13T16:17:26Z

Use l2tp_tunnel_get_nth() instead of l2tp_tunnel_find_nth(), to be safe against concurrent tunnel deletion. Use the same mechanism as in l2tp_ppp.c for dropping the reference taken by l2tp_tunnel_get_nth(). That is, drop the reference just before looking up the next tunnel. In case of error, drop the last accessed tunnel in l2tp_dfs_seq_stop(). That was the last use of l2tp_tunnel_find_nth(). Fixes: 0ad6614048cf ("l2tp: Add debugfs files for dumping l2tp debug info") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

l2tp: remove l2specific_len configurable parameter

2018-01-19T20:00:49Z

Remove l2specific_len configuration parameter since now L2-Specific Sublayer length is computed according to l2specific_type provided by userspace. Reviewed-by: Guillaume Nault Tested-by: Guillaume Nault Signed-off-by: Lorenzo Bianconi Signed-off-by: David S. Miller

l2tp: remove configurable payload offset

2018-01-05T16:03:19Z

If L2TP_ATTR_OFFSET is set to a non-zero value in L2TPv3 tunnels, it results in L2TPv3 packets being transmitted which might not be compliant with the L2TPv3 RFC. This patch has l2tp ignore the offset setting and send all packets with no offset. In more detail: L2TPv2 supports a variable offset from the L2TPv2 header to the payload. The offset value is indicated by an optional field in the L2TP header. Our L2TP implementation already detects the presence of the optional offset and skips that many bytes when handling data received packets. All transmitted packets are always transmitted with no offset. L2TPv3 has no optional offset field in the L2TPv3 packet header. Instead, L2TPv3 defines optional fields in a "Layer-2 Specific Sublayer". At the time when the original L2TP code was written, there was talk at IETF of offset being implemented in a new Layer-2 Specific Sublayer. A L2TP_ATTR_OFFSET netlink attribute was added so that this offset could be configured and the intention was to allow it to be also used to set the tx offset for L2TPv2. However, no L2TPv3 offset was ever specified and the L2TP_ATTR_OFFSET parameter was forgotten about. Setting L2TP_ATTR_OFFSET results in L2TPv3 packets being transmitted with the specified number of bytes padding between L2TPv3 header and payload. This is not compliant with L2TPv3 RFC3931. This change removes the configurable offset altogether while retaining L2TP_ATTR_OFFSET for backwards compatibility. Any L2TP_ATTR_OFFSET value is ignored. Signed-off-by: James Chapman Signed-off-by: David S. Miller

l2tp: revert "l2tp: add peer_offset parameter"

2018-01-05T16:03:04Z

Revert commit f15bc54eeecd ("l2tp: add peer_offset parameter"). This is removed because it is adding another configurable offset and configurable offsets are being removed. Signed-off-by: James Chapman Signed-off-by: David S. Miller