l2tp: improve tunnel/session refcount helpers

l2tp_tunnel_inc_refcount and l2tp_session_inc_refcount wrap
refcount_inc. They add no value so just use the refcount APIs directly
and drop l2tp's helpe

l2tp: improve tunnel/session refcount helpers

l2tp_tunnel_inc_refcount and l2tp_session_inc_refcount wrap
refcount_inc. They add no value so just use the refcount APIs directly
and drop l2tp's helpers. l2tp already uses refcount_inc_not_zero
anyway.

Rename l2tp_tunnel_dec_refcount and l2tp_session_dec_refcount to
l2tp_tunnel_put and l2tp_session_put to better match their use pairing
various _get getters.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: use get_next APIs for management requests and procfs/debugfs

l2tp netlink and procfs/debugfs iterate over tunnel and session lists
to obtain data. They currently use very inefficient get_nth f

l2tp: use get_next APIs for management requests and procfs/debugfs

l2tp netlink and procfs/debugfs iterate over tunnel and session lists
to obtain data. They currently use very inefficient get_nth functions
to do so. Replace these with get_next.

For netlink, use nl cb->ctx[] for passing state instead of the
obsolete cb->args[].

l2tp_tunnel_get_nth and l2tp_session_get_nth are no longer used so
they can be removed.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: add tunnel/session get_next helpers

l2tp management APIs and procfs/debugfs iterate over l2tp tunnel and
session lists. Since these lists are now implemented using IDR, we can
use IDR get_next

l2tp: add tunnel/session get_next helpers

l2tp management APIs and procfs/debugfs iterate over l2tp tunnel and
session lists. Since these lists are now implemented using IDR, we can
use IDR get_next APIs to iterate them. Add tunnel/session get_next
functions to do so.

The session get_next functions get the next session in a given tunnel
and need to account for l2tpv2 and l2tpv3 differences:

* l2tpv2 sessions are keyed by tunnel ID / session ID. Iteration for
a given tunnel ID, TID, can therefore start with a key given by
TID/0 and finish when the next entry's tunnel ID is not TID. This
is possible only because the tunnel ID part of the key is the upper
16 bits and the session ID part the lower 16 bits; when idr_next
increments the key value, it therefore finds the next sessions of
the current tunnel before those of the next tunnel. Entries with
session ID 0 are always skipped because they are used internally by
pppol2tp.

* l2tpv3 sessions are keyed by session ID. Iteration starts at the
first IDR entry and skips entries where the tunnel does not
match. Iteration must also consider session ID collisions and walk
the list of colliding sessions (if any) for one which matches the
supplied tunnel.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: prevent possible tunnel refcount underflow

When a session is created, it sets a backpointer to its tunnel. When
the session refcount drops to 0, l2tp_session_free drops the tunnel
refcount if

l2tp: prevent possible tunnel refcount underflow

When a session is created, it sets a backpointer to its tunnel. When
the session refcount drops to 0, l2tp_session_free drops the tunnel
refcount if session->tunnel is non-NULL. However, session->tunnel is
set in l2tp_session_create, before the tunnel refcount is incremented
by l2tp_session_register, which leaves a small window where
session->tunnel is non-NULL when the tunnel refcount hasn't been
bumped.

Moving the assignment to l2tp_session_register is trivial but
l2tp_session_create calls l2tp_session_set_header_len which uses
session->tunnel to get the tunnel's encap. Add an encap arg to
l2tp_session_set_header_len to avoid using session->tunnel.

If l2tpv3 sessions have colliding IDs, it is possible for
l2tp_v3_session_get to race with l2tp_session_register and fetch a
session which doesn't yet have session->tunnel set. Add a check for
this case.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: free sessions using rcu

l2tp sessions may be accessed under an rcu read lock. Have them freed
via rcu and remove the now unneeded synchronize_rcu when a session is
removed.

Signed-off-by: Jam

l2tp: free sessions using rcu

l2tp sessions may be accessed under an rcu read lock. Have them freed
via rcu and remove the now unneeded synchronize_rcu when a session is
removed.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: delete sessions using work queue

When a tunnel is closed, l2tp_tunnel_closeall closes all sessions in
the tunnel. Move the work of deleting each session to the work queue
so that sessions are

l2tp: delete sessions using work queue

When a tunnel is closed, l2tp_tunnel_closeall closes all sessions in
the tunnel. Move the work of deleting each session to the work queue
so that sessions are deleted using the same codepath whether they are
closed by user API request or their parent tunnel is closing. This
also avoids the locking dance in l2tp_tunnel_closeall where the
tunnel's session list lock was unlocked and relocked in the loop.

In l2tp_exit_net, use drain_workqueue instead of flush_workqueue
because the processing of tunnel_delete work may queue session_delete
work items which must also be processed.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: simplify tunnel and socket cleanup

When the l2tp tunnel socket used sk_user_data to point to its
associated l2tp tunnel, socket and tunnel cleanup had to make use of
the socket's destructor to

l2tp: simplify tunnel and socket cleanup

When the l2tp tunnel socket used sk_user_data to point to its
associated l2tp tunnel, socket and tunnel cleanup had to make use of
the socket's destructor to free the tunnel only when the socket could
no longer be accessed.

Now that sk_user_data is no longer used, we can simplify socket and
tunnel cleanup:

* If the tunnel closes first, it cleans up and drops its socket ref
when the tunnel refcount drops to zero. If its socket was provided
by userspace, the socket is closed and freed asynchronously, when
userspace closes it. If its socket is a kernel socket, the tunnel
closes the socket itself during cleanup and drops its socket ref
when the tunnel's refcount drops to zero.

* If the socket closes first, we initiate the closing of its
associated tunnel. For UDP sockets, this is via the socket's
encap_destroy hook. For L2TPIP sockets, this is via the socket's
destroy callback. The tunnel holds a socket ref while it
references the sock. When the tunnel is freed, it drops its socket
ref and the socket will be cleaned up when its own refcount drops
to zero, asynchronous to the tunnel free.

* The tunnel socket destructor is no longer needed since the tunnel
is no longer freed through the socket destructor.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: remove unused tunnel magic field

Since l2tp no longer derives tunnel pointers directly via
sk_user_data, it is no longer useful for l2tp to check tunnel pointers
using a magic feather. Drop th

l2tp: remove unused tunnel magic field

Since l2tp no longer derives tunnel pointers directly via
sk_user_data, it is no longer useful for l2tp to check tunnel pointers
using a magic feather. Drop the tunnel's magic field.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: lookup tunnel from socket without using sk_user_data

l2tp_sk_to_tunnel derives the tunnel from sk_user_data. Instead,
lookup the tunnel by walking the tunnel IDR for a tunnel using the
indicat

l2tp: lookup tunnel from socket without using sk_user_data

l2tp_sk_to_tunnel derives the tunnel from sk_user_data. Instead,
lookup the tunnel by walking the tunnel IDR for a tunnel using the
indicated sock. This is slow but l2tp_sk_to_tunnel is not used in
the datapath so performance isn't critical.

l2tp_tunnel_destruct needs a variant of l2tp_sk_to_tunnel which does
not bump the tunnel refcount since the tunnel refcount is already 0.

Change l2tp_sk_to_tunnel sk arg to const since it does not modify sk.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: replace hlist with simple list for per-tunnel session list

The per-tunnel session list is no longer used by the
datapath. However, we still need a list of sessions in the tunnel for
l2tp_sessi

l2tp: replace hlist with simple list for per-tunnel session list

The per-tunnel session list is no longer used by the
datapath. However, we still need a list of sessions in the tunnel for
l2tp_session_get_nth, which is used by management code. (An
alternative might be to walk each session IDR list, matching only
sessions of a given tunnel.)

Replace the per-tunnel hlist with a per-tunnel list. In functions
which walk a list of sessions of a tunnel, walk this list instead.

Signed-off-by: James Chapman <jchapman@katalix.com>
Reviewed-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: drop the now unused l2tp_tunnel_get_session

All users of l2tp_tunnel_get_session are now gone so it can be
removed.

Signed-off-by: James Chapman <jchapman@katalix.com>
Reviewed-by: Tom Parkin

l2tp: drop the now unused l2tp_tunnel_get_session

All users of l2tp_tunnel_get_session are now gone so it can be
removed.

Signed-off-by: James Chapman <jchapman@katalix.com>
Reviewed-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: use IDR for all session lookups

Add generic session getter which uses IDR. Replace all users of
l2tp_tunnel_get_session which uses the per-tunnel session list to use
the generic getter.

Signe

l2tp: use IDR for all session lookups

Add generic session getter which uses IDR. Replace all users of
l2tp_tunnel_get_session which uses the per-tunnel session list to use
the generic getter.

Signed-off-by: James Chapman <jchapman@katalix.com>
Reviewed-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: store l2tpv2 sessions in per-net IDR

L2TPv2 sessions are currently kept in a per-tunnel hashlist, keyed by
16-bit session_id. When handling received L2TPv2 packets, we need to
first derive the

l2tp: store l2tpv2 sessions in per-net IDR

L2TPv2 sessions are currently kept in a per-tunnel hashlist, keyed by
16-bit session_id. When handling received L2TPv2 packets, we need to
first derive the tunnel using the 16-bit tunnel_id or sock, then
lookup the session in a per-tunnel hlist using the 16-bit session_id.

We want to avoid using sk_user_data in the datapath and double lookups
on every packet. So instead, use a per-net IDR to hold L2TPv2
sessions, keyed by a 32-bit value derived from the 16-bit tunnel_id
and session_id. This will allow the L2TPv2 UDP receive datapath to
lookup a session with a single lookup without deriving the tunnel
first.

L2TPv2 sessions are held in their own IDR to avoid potential
key collisions with L2TPv3 sessions.

Signed-off-by: James Chapman <jchapman@katalix.com>
Reviewed-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: store l2tpv3 sessions in per-net IDR

L2TPv3 sessions are currently held in one of two fixed-size hash
lists: either a per-net hashlist (IP-encap), or a per-tunnel hashlist
(UDP-encap), keyed b

l2tp: store l2tpv3 sessions in per-net IDR

L2TPv3 sessions are currently held in one of two fixed-size hash
lists: either a per-net hashlist (IP-encap), or a per-tunnel hashlist
(UDP-encap), keyed by the L2TPv3 32-bit session_id.

In order to lookup L2TPv3 sessions in UDP-encap tunnels efficiently
without finding the tunnel first via sk_user_data, UDP sessions are
now kept in a per-net session list, keyed by session ID. Convert the
existing per-net hashlist to use an IDR for better performance when
there are many sessions and have L2TPv3 UDP sessions use the same IDR.

Although the L2TPv3 RFC states that the session ID alone identifies
the session, our implementation has allowed the same session ID to be
used in different L2TP UDP tunnels. To retain support for this, a new
per-net session hashtable is used, keyed by the sock and session
ID. If on creating a new session, a session already exists with that
ID in the IDR, the colliding sessions are added to the new hashtable
and the existing IDR entry is flagged. When looking up sessions, the
approach is to first check the IDR and if no unflagged match is found,
check the new hashtable. The sock is made available to session getters
where session ID collisions are to be considered. In this way, the new
hashtable is used only for session ID collisions so can be kept small.

For managing session removal, we need a list of colliding sessions
matching a given ID in order to update or remove the IDR entry of the
ID. This is necessary to detect session ID collisions when future
sessions are created. The list head is allocated on first collision
of a given ID and refcounted.

Signed-off-by: James Chapman <jchapman@katalix.com>
Reviewed-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: remove unused list_head member in l2tp_tunnel

Remove an unused variable in struct l2tp_tunnel which was left behind
by commit c4d48a58f32c5 ("l2tp: convert l2tp_tunnel_list to idr").

Signed-o

l2tp: remove unused list_head member in l2tp_tunnel

Remove an unused variable in struct l2tp_tunnel which was left behind
by commit c4d48a58f32c5 ("l2tp: convert l2tp_tunnel_list to idr").

Signed-off-by: James Chapman <jchapman@katalix.com>
Reviewed-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net: ioctl: Use kernel memory on protocol ioctl callbacks

Most of the ioctls to net protocols operates directly on userspace
argument (arg). Usually doing get_user()/put_user() directly in the
ioctl

net: ioctl: Use kernel memory on protocol ioctl callbacks

Most of the ioctls to net protocols operates directly on userspace
argument (arg). Usually doing get_user()/put_user() directly in the
ioctl callback. This is not flexible, because it is hard to reuse these
functions without passing userspace buffers.

Change the "struct proto" ioctls to avoid touching userspace memory and
operate on kernel buffers, i.e., all protocol's ioctl callbacks is
adapted to operate on a kernel memory other than on userspace (so, no
more {put,get}_user() and friends being called in the ioctl callback).

This changes the "struct proto" ioctl format in the following way:

int (*ioctl)(struct sock *sk, int cmd,
- unsigned long arg);
+ int *karg);

(Important to say that this patch does not touch the "struct proto_ops"
protocols)

So, the "karg" argument, which is passed to the ioctl callback, is a
pointer allocated to kernel space memory (inside a function wrapper).
This buffer (karg) may contain input argument (copied from userspace in
a prep function) and it might return a value/buffer, which is copied
back to userspace if necessary. There is not one-size-fits-all format
(that is I am using 'may' above), but basically, there are three type of
ioctls:

1) Do not read from userspace, returns a result to userspace
2) Read an input parameter from userspace, and does not return anything
to userspace
3) Read an input from userspace, and return a buffer to userspace.

The default case (1) (where no input parameter is given, and an "int" is
returned to userspace) encompasses more than 90% of the cases, but there
are two other exceptions. Here is a list of exceptions:

* Protocol RAW:
* cmd = SIOCGETVIFCNT:
* input and output = struct sioc_vif_req
* cmd = SIOCGETSGCNT
* input and output = struct sioc_sg_req
* Explanation: for the SIOCGETVIFCNT case, userspace passes the input
argument, which is struct sioc_vif_req. Then the callback populates
the struct, which is copied back to userspace.

* Protocol RAW6:
* cmd = SIOCGETMIFCNT_IN6
* input and output = struct sioc_mif_req6
* cmd = SIOCGETSGCNT_IN6
* input and output = struct sioc_sg_req6

* Protocol PHONET:
* cmd == SIOCPNADDRESOURCE | SIOCPNDELRESOURCE
* input int (4 bytes)
* Nothing is copied back to userspace.

For the exception cases, functions sock_sk_ioctl_inout() will
copy the userspace input, and copy it back to kernel space.

The wrapper that prepare the buffer and put the buffer back to user is
sk_ioctl(), so, instead of calling sk->sk_prot->ioctl(), the callee now
calls sk_ioctl(), which will handle all cases.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230609152800.830401-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net/l2tp: convert tunnel rwlock_t to rcu

Previously commit e02d494d2c60 ("l2tp: Convert rwlock to RCU") converted
most, but not all, rwlock instances in the l2tp subsystem to RCU.

The remaining rwl

net/l2tp: convert tunnel rwlock_t to rcu

Previously commit e02d494d2c60 ("l2tp: Convert rwlock to RCU") converted
most, but not all, rwlock instances in the l2tp subsystem to RCU.

The remaining rwlock protects the per-tunnel hashlist of sessions which
is used for session lookups in the UDP-encap data path.

Convert the remaining rwlock to rcu to improve performance of UDP-encap
tunnels.

Note that the tunnel and session, which both live on RCU-protected
lists, use slightly different approaches to incrementing their refcounts
in the various getter functions.

The tunnel has to use refcount_inc_not_zero because the tunnel shutdown
process involves dropping the refcount to zero prior to synchronizing
RCU readers (via. kfree_rcu).

By contrast, the session shutdown removes the session from the list(s)
it is on, synchronizes with readers, and then decrements the session
refcount. Since the getter functions increment the session refcount
with the RCU read lock held we prevent getters seeing a zero session
refcount, and therefore don't need to use refcount_inc_not_zero.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net: l2tp: reduce log level of messages in receive path, add counter instead

Commit 5ee759cda51b ("l2tp: use standard API for warning log messages")
changed a number of warnings about invalid packet

net: l2tp: reduce log level of messages in receive path, add counter instead

Commit 5ee759cda51b ("l2tp: use standard API for warning log messages")
changed a number of warnings about invalid packets in the receive path
so that they are always shown, instead of only when a special L2TP debug
flag is set. Even with rate limiting these warnings can easily cause
significant log spam - potentially triggered by a malicious party
sending invalid packets on purpose.

In addition these warnings were noticed by projects like Tunneldigger [1],
which uses L2TP for its data path, but implements its own control
protocol (which is sufficiently different from L2TP data packets that it
would always be passed up to userspace even with future extensions of
L2TP).

Some of the warnings were already redundant, as l2tp_stats has a counter
for these packets. This commit adds one additional counter for invalid
packets that are passed up to userspace. Packets with unknown session are
not counted as invalid, as there is nothing wrong with the format of
these packets.

With the additional counter, all of these messages are either redundant
or benign, so we reduce them to pr_debug_ratelimited().

[1] https://github.com/wlanslovenija/tunneldigger/issues/160

Fixes: 5ee759cda51b ("l2tp: use standard API for warning log messages")
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: make magic feather checks more useful

The l2tp tunnel and session structures contain a "magic feather" field
which was originally intended to help trace lifetime bugs in the code.

Since the i

l2tp: make magic feather checks more useful

The l2tp tunnel and session structures contain a "magic feather" field
which was originally intended to help trace lifetime bugs in the code.

Since the introduction of the shared kernel refcount code in refcount.h,
and l2tp's porting to those APIs, we are covered by the refcount code's
checks and warnings. Duplicating those checks in the l2tp code isn't
useful.

However, magic feather checks are still useful to help to detect bugs
stemming from misuse/trampling of the sk_user_data pointer in struct
sock. The l2tp code makes extensive use of sk_user_data to stash
pointers to the tunnel and session structures, and if another subsystem
overwrites sk_user_data it's important to detect this.

As such, rework l2tp's magic feather checks to focus on validating the
tunnel and session data structures when they're extracted from
sk_user_data.

* Add a new accessor function l2tp_sk_to_tunnel which contains a magic
feather check, and is used by l2tp_core and l2tp_ip[6]
* Comment l2tp_udp_encap_recv which doesn't use this new accessor function
because of the specific nature of the codepath it is called in
* Drop l2tp_session_queue_purge's check on the session magic feather:
it is called from code which is walking the tunnel session list, and
hence doesn't need validation
* Drop l2tp_session_free's check on the tunnel magic feather: the
intention of this check is covered by refcount.h's reference count
sanity checking
* Add session magic validation in pppol2tp_ioctl. On failure return
-EBADF, which mirrors the approach in pppol2tp_[sg]etsockopt.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: drop net argument from l2tp_tunnel_create

The argument is unused, so remove it.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

l2tp: remove header length param from l2tp_xmit_skb

All callers pass the session structure's hdr_len field as the header
length parameter to l2tp_xmit_skb.

Since we're passing a pointer to the sess

l2tp: remove header length param from l2tp_xmit_skb

All callers pass the session structure's hdr_len field as the header
length parameter to l2tp_xmit_skb.

Since we're passing a pointer to the session structure to l2tp_xmit_skb
anyway, there's not much point breaking the header length out as a
separate argument.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: remove tunnel and session debug flags field

The l2tp subsystem now uses standard kernel logging APIs for
informational and warning messages, and tracepoints for debug
information.

Now that th

l2tp: remove tunnel and session debug flags field

The l2tp subsystem now uses standard kernel logging APIs for
informational and warning messages, and tracepoints for debug
information.

Now that the tunnel and session debug flags are unused, remove the field
from the core structures.

Various system calls (in the case of l2tp_ppp) and netlink messages
handle the getting and setting of debug flags. To avoid userspace
breakage don't modify the API of these calls; simply ignore set
requests, and send dummy data for get requests.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: remove custom logging macros

All l2tp's informational and warning logging is now carried out using
standard kernel APIs.

Debugging information is now handled using tracepoints.

Now that no c

l2tp: remove custom logging macros

All l2tp's informational and warning logging is now carried out using
standard kernel APIs.

Debugging information is now handled using tracepoints.

Now that no code is using the custom logging macros, remove them from
l2tp_core.h.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: add tracepoint definitions in trace.h

l2tp can provide a better debug experience using tracepoints rather than
printk-style logging.

Add tracepoint definitions in trace.h for use in the l2tp

l2tp: add tracepoint definitions in trace.h

l2tp can provide a better debug experience using tracepoints rather than
printk-style logging.

Add tracepoint definitions in trace.h for use in the l2tp subsystem
code.

Add preprocessor definitions for the length of session and tunnel names
in l2tp_core.h so we can reuse these in trace.h.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

l2tp: improve API documentation in l2tp_core.h

* Improve the description of the key l2tp subsystem data structures.
* Add high-level description of the main APIs for interacting with l2tp
core.

l2tp: improve API documentation in l2tp_core.h

* Improve the description of the key l2tp subsystem data structures.
* Add high-level description of the main APIs for interacting with l2tp
core.
* Add documentation for the l2tp netlink session command callbacks.
* Document the session pseudowire callbacks.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...