rxrpc: Use ktimes for call timeout tracking and set the timer lazily

Track the call timeouts as ktimes rather than jiffies as the latter's
granularity is too high and only set the timer at the end of the event
handling function.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org

rxrpc, afs: Allow afs to pin rxrpc_peer objects

Change rxrpc's API such that:

(1) A new function, rxrpc_kernel_lookup_peer(), is provided to look up an
rxrpc_peer record for a remote address and a corresponding function,
rxrpc_kernel_put_peer(), is provided to dispose of it again.

(2) When setting up a call, the rxrpc_peer object used during a call is
now passed in rather than being set up by rxrpc_connect_call(). For
afs, this meenat passing it to rxrpc_kernel_begin_call() rather than
the full address (the service ID then has to be passed in as a
separate parameter).

(3) A new function, rxrpc_kernel_remote_addr(), is added so that afs can
get a pointer to the transport address for display purposed, and
another, rxrpc_kernel_remote_srx(), to gain a pointer to the full
rxrpc address.

(4) The function to retrieve the RTT from a call, rxrpc_kernel_get_srtt(),
is then altered to take a peer. This now returns the RTT or -1 if
there are insufficient samples.

(5) Rename rxrpc_kernel_get_peer() to rxrpc_kernel_call_get_peer().

(6) Provide a new function, rxrpc_kernel_get_peer(), to get a ref on a
peer the caller already has.

This allows the afs filesystem to pin the rxrpc_peer records that it is
using, allowing faster lookups and pointer comparisons rather than
comparing sockaddr_rxrpc contents. It also makes it easier to get hold of
the RTT. The following changes are made to afs:

(1) The addr_list struct's addrs[] elements now hold a peer struct pointer
and a service ID rather than a sockaddr_rxrpc.

(2) When displaying the transport address, rxrpc_kernel_remote_addr() is
used.

(3) The port arg is removed from afs_alloc_addrlist() since it's always
overridden.

(4) afs_merge_fs_addr4() and afs_merge_fs_addr6() do peer lookup and may
now return an error that must be handled.

(5) afs_find_server() now takes a peer pointer to specify the address.

(6) afs_find_server(), afs_compare_fs_alists() and afs_merge_fs_addr[46]{}
now do peer pointer comparison rather than address comparison.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES)

Remove ->sendpage() and ->sendpage_locked(). sendmsg() with
MSG_SPLICE_PAGES should be used instead. This allows multiple pages and
multipage folios to be passed through.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> # for net/can
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-afs@lists.infradead.org
cc: mptcp@lists.linux.dev
cc: rds-devel@oss.oracle.com
cc: tipc-discussion@lists.sourceforge.net
cc: virtualization@lists.linux-foundation.org
Link: https://lore.kernel.org/r/20230623225513.2732256-16-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

rxrpc: Truncate UTS_RELEASE for rxrpc version

UTS_RELEASE has a maximum length of 64 which can cause rxrpc_version to
exceed the 65 byte message limit.

Per the rx spec[1]: "If a server receives a packet with a type value of 13,
and the client-initiated flag set, it should respond with a 65-byte payload
containing a string that identifies the version of AFS software it is
running."

The current implementation causes a compile error when WERROR is turned on
and/or UTS_RELEASE exceeds the length of 49 (making the version string more
than 64 characters).

Fix this by generating the string during module initialisation and limiting
the UTS_RELEASE segment of the string does not exceed 49 chars. We need to
make sure that the 64 bytes includes "linux-" at the front and " AF_RXRPC"
at the back as this may be used in pattern matching.

Fixes: 44ba06987c0b ("RxRPC: Handle VERSION Rx protocol packets")
Reported-by: Kenny Ho <Kenny.Ho@amd.com>
Link: https://lore.kernel.org/r/20230523223944.691076-1-Kenny.Ho@amd.com/
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Kenny Ho <Kenny.Ho@amd.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Andrew Lunn <andrew@lunn.ch>
cc: David Laight <David.Laight@ACULAB.COM>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
Link: https://web.mit.edu/kolya/afs/rx/rx-spec [1]
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
Link: https://lore.kernel.org/r/654974.1685100894@warthog.procyon.org.uk
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

rxrpc: Use alloc_ordered_workqueue() to create ordered workqueues

BACKGROUND
==========

When multiple work items are queued to a workqueue, their execution order
doesn't match the queueing order. They may get executed in any order and
simultaneously. When fully serialized execution - one by one in the queueing
order - is needed, an ordered workqueue should be used which can be created
with alloc_ordered_workqueue().

However, alloc_ordered_workqueue() was a later addition. Before it, an
ordered workqueue could be obtained by creating an UNBOUND workqueue with
@max_active==1. This originally was an implementation side-effect which was
broken by 4c16bd327c74 ("workqueue: restore WQ_UNBOUND/max_active==1 to be
ordered"). Because there were users that depended on the ordered execution,
5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered")
made workqueue allocation path to implicitly promote UNBOUND workqueues w/
@max_active==1 to ordered workqueues.

While this has worked okay, overloading the UNBOUND allocation interface
this way creates other issues. It's difficult to tell whether a given
workqueue actually needs to be ordered and users that legitimately want a
min concurrency level wq unexpectedly gets an ordered one instead. With
planned UNBOUND workqueue updates to improve execution locality and more
prevalence of chiplet designs which can benefit from such improvements, this
isn't a state we wanna be in forever.

This patch series audits all callsites that create an UNBOUND workqueue w/
@max_active==1 and converts them to alloc_ordered_workqueue() as necessary.

WHAT TO LOOK FOR
================

The conversions are from

alloc_workqueue(WQ_UNBOUND | flags, 1, args..)

to

alloc_ordered_workqueue(flags, args...)

which don't cause any functional changes. If you know that fully ordered
execution is not necessary, please let me know. I'll drop the conversion and
instead add a comment noting the fact to reduce confusion while conversion
is in progress.

If you aren't fully sure, it's completely fine to let the conversion
through. The behavior will stay exactly the same and we can always
reconsider later.

As there are follow-up workqueue core changes, I'd really appreciate if the
patch can be routed through the workqueue tree w/ your acks. Thanks.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: linux-afs@lists.infradead.org
Cc: netdev@vger.kernel.org

rxrpc: Fix timeout of a call that hasn't yet been granted a channel

afs_make_call() calls rxrpc_kernel_begin_call() to begin a call (which may
get stalled in the background waiting for a connection to become
available); it then calls rxrpc_kernel_set_max_life() to set the timeouts -
but that starts the call timer so the call timer might then expire before
we get a connection assigned - leading to the following oops if the call
stalled:

BUG: kernel NULL pointer dereference, address: 0000000000000000
...
CPU: 1 PID: 5111 Comm: krxrpcio/0 Not tainted 6.3.0-rc7-build3+ #701
RIP: 0010:rxrpc_alloc_txbuf+0xc0/0x157
...
Call Trace:
<TASK>
rxrpc_send_ACK+0x50/0x13b
rxrpc_input_call_event+0x16a/0x67d
rxrpc_io_thread+0x1b6/0x45f
? _raw_spin_unlock_irqrestore+0x1f/0x35
? rxrpc_input_packet+0x519/0x519
kthread+0xe7/0xef
? kthread_complete_and_exit+0x1b/0x1b
ret_from_fork+0x22/0x30

Fix this by noting the timeouts in struct rxrpc_call when the call is
created. The timer will be started when the first packet is transmitted.

It shouldn't be possible to trigger this directly from userspace through
AF_RXRPC as sendmsg() will return EBUSY if the call is in the
waiting-for-conn state if it dropped out of the wait due to a signal.

Fixes: 9d35d880e0e4 ("rxrpc: Move client call connection to the I/O thread")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Fix potential race in error handling in afs_make_call()

If the rxrpc call set up by afs_make_call() receives an error whilst it is
transmitting the request, there's the possibility that it may get to the
point the rxrpc call is ended (after the error_kill_call label) just as the
call is queued for async processing.

This could manifest itself as call->rxcall being seen as NULL in
afs_deliver_to_call() when it tries to lock the call.

Fix this by splitting rxrpc_kernel_end_call() into a function to shut down
an rxrpc call and a function to release the caller's reference and calling
the latter only when we get to afs_put_call().

Reported-by: Jeffrey Altman <jaltman@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: kafs-testing+fedora36_64checkkafs-build-306@auristor.com
cc: Marc Dionne <marc.dionne@auristor.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Convert call->recvmsg_lock to a spinlock

Convert call->recvmsg_lock to a spinlock as it's only ever write-locked.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

rxrpc: Fix incoming call setup race

An incoming call can race with rxrpc socket destruction, leading to a
leaked call. This may result in an oops when the call timer eventually
expires:

BUG: kernel NULL pointer dereference, address: 0000000000000874
RIP: 0010:_raw_spin_lock_irqsave+0x2a/0x50
Call Trace:
<IRQ>
try_to_wake_up+0x59/0x550
? __local_bh_enable_ip+0x37/0x80
? rxrpc_poke_call+0x52/0x110 [rxrpc]
? rxrpc_poke_call+0x110/0x110 [rxrpc]
? rxrpc_poke_call+0x110/0x110 [rxrpc]
call_timer_fn+0x24/0x120

with a warning in the kernel log looking something like:

rxrpc: Call 00000000ba5e571a still in use (1,SvAwtACK,1061d,0)!

incurred during rmmod of rxrpc. The 1061d is the call flags:

RECVMSG_READ_ALL, RX_HEARD, BEGAN_RX_TIMER, RX_LAST, EXPOSED,
IS_SERVICE, RELEASED

but no DISCONNECTED flag (0x800), so it's an incoming (service) call and
it's still connected.

The race appears to be that:

(1) rxrpc_new_incoming_call() consults the service struct, checks sk_state
and allocates a call - then pauses, possibly for an interrupt.

(2) rxrpc_release_sock() sets RXRPC_CLOSE, nulls the service pointer,
discards the prealloc and releases all calls attached to the socket.

(3) rxrpc_new_incoming_call() resumes, launching the new call, including
its timer and attaching it to the socket.

Fix this by read-locking local->services_lock to access the AF_RXRPC socket
providing the service rather than RCU in rxrpc_new_incoming_call().
There's no real need to use RCU here as local->services_lock is only
write-locked by the socket side in two places: when binding and when
shutting down.

Fixes: 5e6ef4f1017c ("rxrpc: Make the I/O thread take over the call and local processor work")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-afs@lists.infradead.org

rxrpc: Move call state changes from recvmsg to I/O thread

Move the call state changes that are made in rxrpc_recvmsg() to the I/O
thread. This means that, thenceforth, only the I/O thread does this and
the call state lock can be removed.

This requires the Rx phase to be ended when the last packet is received,
not when it is processed.

Since this now changes the rxrpc call state to SUCCEEDED before we've
consumed all the data from it, rxrpc_kernel_check_life() mustn't say the
call is dead until the recvmsg queue is empty (unless the call has failed).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

rxrpc: Wrap accesses to get call state to put the barrier in one place

Wrap accesses to get the state of a call from outside of the I/O thread in
a single place so that the barrier needed to order wrt the error code and
abort code is in just that place.

Also use a barrier when setting the call state and again when reading the
call state such that the auxiliary completion info (error code, abort code)
can be read without taking a read lock on the call state lock.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

rxrpc: Set up a connection bundle from a call, not rxrpc_conn_parameters

Use the information now stored in struct rxrpc_call to configure the
connection bundle and thence the connection, rather than using the
rxrpc_conn_parameters struct.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

rxrpc: Make the set of connection IDs per local endpoint

Make the set of connection IDs per local endpoint so that endpoints don't
cause each other's connections to get dismissed.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

rxrpc: Remove the _bh annotation from all the spinlocks

None of the spinlocks in rxrpc need a _bh annotation now as the RCU
callback routines no longer take spinlocks and the bulk of the packet
wrangling code is now run in the I/O thread, not softirq context.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

rxrpc: Don't use sk->sk_receive_queue.lock to guard socket state changes

Don't use sk->sk_receive_queue.lock to guard socket state changes as the
socket mutex is sufficient.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

rxrpc: trace: Don't use __builtin_return_address for rxrpc_peer tracing

In rxrpc tracing, use enums to generate lists of points of interest rather
than __builtin_return_address() for the rxrpc_peer tracepoint

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

rxrpc: trace: Don't use __builtin_return_address for rxrpc_local tracing

In rxrpc tracing, use enums to generate lists of points of interest rather
than __builtin_return_address() for the rxrpc_local tracepoint

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

rxrpc: Fix network address validation

Fix network address validation on entry to uapi functions such as connect()
for AF_RXRPC. The check for address compatibility with the transport
socket isn't correct and allows an AF_INET6 address to be given to an
AF_INET socket, resulting in an oops now that rxrpc is calling
udp_sendmsg() directly.

Sample program:

#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <linux/rxrpc.h>
static unsigned char ctrl[256] =
"\x18\x00\x00\x00\x00\x00\x00\x00\x10\x01\x00\x00\x01";
int main(void)
{
struct sockaddr_rxrpc srx = {
.srx_family = AF_RXRPC,
.transport_type = SOCK_DGRAM,
.transport_len = 28,
.transport.sin6.sin6_family = AF_INET6,
};
struct mmsghdr vec = {
.msg_hdr.msg_control = ctrl,
.msg_hdr.msg_controllen = 0x18,
};
int s;
s = socket(AF_RXRPC, SOCK_DGRAM, AF_INET);
if (s < 0) {
perror("socket");
exit(1);
}
if (connect(s, (struct sockaddr *)&srx, sizeof(srx)) < 0) {
perror("connect");
exit(1);
}
if (sendmmsg(s, &vec, 1, MSG_NOSIGNAL | MSG_MORE) < 0) {
perror("sendmmsg");
exit(1);
}
return 0;
}

If working properly, connect() should fail with EAFNOSUPPORT.

Fixes: ed472b0c8783 ("rxrpc: Call udp_sendmsg() directly")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

rxrpc: Don't use a ring buffer for call Tx queue

Change the way the Tx queueing works to make the following ends easier to
achieve:

(1) The filling of packets, the encryption of packets and the transmission
of packets can be handled in parallel by separate threads, rather than
rxrpc_sendmsg() allocating, filling, encrypting and transmitting each
packet before moving onto the next one.

(2) Get rid of the fixed-size ring which sets a hard limit on the number
of packets that can be retained in the ring. This allows the number
of packets to increase without having to allocate a very large ring or
having variable-sized rings.

[Note: the downside of this is that it's then less efficient to locate
a packet for retransmission as we then have to step through a list and
examine each buffer in the list.]

(3) Allow the filler/encrypter to run ahead of the transmission window.

(4) Make it easier to do zero copy UDP from the packet buffers.

(5) Make it easier to do zero copy from userspace to the packet buffers -
and thence to UDP (only if for unauthenticated connections).

To that end, the following changes are made:

(1) Use the new rxrpc_txbuf struct instead of sk_buff for keeping packets
to be transmitted in. This allows them to be placed on multiple
queues simultaneously. An sk_buff isn't really necessary as it's
never passed on to lower-level networking code.

(2) Keep the transmissable packets in a linked list on the call struct
rather than in a ring. As a consequence, the annotation buffer isn't
used either; rather a flag is set on the packet to indicate ackedness.

(3) Use the RXRPC_CALL_TX_LAST flag to indicate that the last packet to be
transmitted has been queued. Add RXRPC_CALL_TX_ALL_ACKED to indicate
that all packets up to and including the last got hard acked.

(4) Wire headers are now stored in the txbuf rather than being concocted
on the stack and they're stored immediately before the data, thereby
allowing zerocopy of a single span.

(5) Don't bother with instant-resend on transmission failure; rather,
leave it for a timer or an ACK packet to trigger.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

rxrpc: Use refcount_t rather than atomic_t

Move to using refcount_t rather than atomic_t for refcounts in rxrpc.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a break statement instead of letting the code fall
through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

rxrpc: Fix deadlock around release of dst cached on udp tunnel

AF_RXRPC sockets use UDP ports in encap mode. This causes socket and dst
from an incoming packet to get stolen and attached to the UDP socket from
whence it is leaked when that socket is closed.

When a network namespace is removed, the wait for dst records to be cleaned
up happens before the cleanup of the rxrpc and UDP socket, meaning that the
wait never finishes.

Fix this by moving the rxrpc (and, by dependence, the afs) private
per-network namespace registrations to the device group rather than subsys
group. This allows cached rxrpc local endpoints to be cleared and their
UDP sockets closed before we try waiting for the dst records.

The symptom is that lines looking like the following:

unregister_netdevice: waiting for lo to become free

get emitted at regular intervals after running something like the
referenced syzbot test.

Thanks to Vadim for tracking this down and work out the fix.

Reported-by: syzbot+df400f2f24a1677cd7e0@syzkaller.appspotmail.com
Reported-by: Vadim Fedorenko <vfedorenko@novek.ru>
Fixes: 5271953cad31 ("rxrpc: Use the UDP encap_rcv hook")
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vadim Fedorenko <vfedorenko@novek.ru>
Link: https://lore.kernel.org/r/161196443016.3868642.5577440140646403533.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

rxrpc: Impose a maximum number of client calls

Impose a maximum on the number of client rxrpc calls that are allowed
simultaneously. This will be in lieu of a maximum number of client
connections as this is easier to administed as, unlike connections, calls
aren't reusable (to be changed in a subsequent patch)..

This doesn't affect the limits on service calls and connections.

Signed-off-by: David Howells <dhowells@redhat.com>

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

net: pass a sockptr_t into ->setsockopt

Rework the remaining setsockopt code to pass a sockptr_t instead of a
plain user pointer. This removes the last remaining set_fs(KERNEL_DS)
outside of architecture specific code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> [ieee802154]
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: rxrpc: kerneldoc fixes

Simple fixes which require no deep knowledge of the code.

Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: add rxrpc_sock_set_min_security_level

Add a helper to directly set the RXRPC_MIN_SECURITY_LEVEL sockopt from
kernel space without going through a fake uaccess.

Thanks to David Howells for the documentation updates.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

afs: Fix client call Rx-phase signal handling

Fix the handling of signals in client rxrpc calls made by the afs
filesystem. Ignore signals completely, leaving call abandonment or
connection loss to be detected by timeouts inside AF_RXRPC.

Allowing a filesystem call to be interrupted after the entire request has
been transmitted and an abort sent means that the server may or may not
have done the action - and we don't know. It may even be worse than that
for older servers.

Fixes: bc5e3a546d55 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Fix call interruptibility handling

Fix the interruptibility of kernel-initiated client calls so that they're
either only interruptible when they're waiting for a call slot to come
available or they're not interruptible at all. Either way, they're not
interruptible during transmission.

This should help prevent StoreData calls from being interrupted when
writeback is in progress. It doesn't, however, handle interruption during
the receive phase.

Userspace-initiated calls are still interruptable. After the signal has
been handled, sendmsg() will return the amount of data copied out of the
buffer and userspace can perform another sendmsg() call to continue
transmission.

Fixes: bc5e3a546d55 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Fix missing active use pinning of rxrpc_local object

The introduction of a split between the reference count on rxrpc_local
objects and the usage count didn't quite go far enough. A number of kernel
work items need to make use of the socket to perform transmission. These
also need to get an active count on the local object to prevent the socket
from being closed.

Fix this by getting the active count in those places.

Also split out the raw active count get/put functions as these places tend
to hold refs on the rxrpc_local object already, so getting and putting an
extra object ref is just a waste of time.

The problem can lead to symptoms like:

BUG: kernel NULL pointer dereference, address: 0000000000000018
..
CPU: 2 PID: 818 Comm: kworker/u9:0 Not tainted 5.5.0-fscache+ #51
...
RIP: 0010:selinux_socket_sendmsg+0x5/0x13
...
Call Trace:
security_socket_sendmsg+0x2c/0x3e
sock_sendmsg+0x1a/0x46
rxrpc_send_keepalive+0x131/0x1ae
rxrpc_peer_keepalive_worker+0x219/0x34b
process_one_work+0x18e/0x271
worker_thread+0x1a3/0x247
kthread+0xe6/0xeb
ret_from_fork+0x1f/0x30

Fixes: 730c5fd42c1e ("rxrpc: Fix local endpoint refcounting")
Signed-off-by: David Howells <dhowells@redhat.com>

treewide: Use sizeof_field() macro

Replace all the occurrences of FIELD_SIZEOF() with sizeof_field() except
at places where these are defined. Later patches will remove the unused
definition of FIELD_SIZEOF().

This patch is generated using following script:

EXCLUDE_FILES="include/linux/stddef.h|include/linux/kernel.h"

git grep -l -e "\bFIELD_SIZEOF\b" | while read file;
do

if [[ "$file" =~ $EXCLUDE_FILES ]]; then
continue
fi
sed -i -e 's/\bFIELD_SIZEOF\b/sizeof_field/g' $file;
done

Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
Link: https://lore.kernel.org/r/20190924105839.110713-3-pankaj.laxminarayan.bharadiya@intel.com
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: David Miller <davem@davemloft.net> # for net

rxrpc: Fix lack of conn cleanup when local endpoint is cleaned up [ver #2]

When a local endpoint is ceases to be in use, such as when the kafs module
is unloaded, the kernel will emit an assertion failure if there are any
outstanding client connections:

rxrpc: Assertion failed
------------[ cut here ]------------
kernel BUG at net/rxrpc/local_object.c:433!

and even beyond that, will evince other oopses if there are service
connections still present.

Fix this by:

(1) Removing the triggering of connection reaping when an rxrpc socket is
released. These don't actually clean up the connections anyway - and
further, the local endpoint may still be in use through another
socket.

(2) Mark the local endpoint as dead when we start the process of tearing
it down.

(3) When destroying a local endpoint, strip all of its client connections
from the idle list and discard the ref on each that the list was
holding.

(4) When destroying a local endpoint, call the service connection reaper
directly (rather than through a workqueue) to immediately kill off all
outstanding service connections.

(5) Make the service connection reaper reap connections for which the
local endpoint is marked dead.

Only after destroying the connections can we close the socket lest we get
an oops in a workqueue that's looking at a connection or a peer.

Fixes: 3d18cbb7fd0c ("rxrpc: Fix conn expiry timers")
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Don't bother generating maxSkew in the ACK packet

Don't bother generating maxSkew in the ACK packet as it has been obsolete
since AFS 3.1.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>

rxrpc: Fix local endpoint refcounting

The object lifetime management on the rxrpc_local struct is broken in that
the rxrpc_local_processor() function is expected to clean up and remove an
object - but it may get requeued by packets coming in on the backing UDP
socket once it starts running.

This may result in the assertion in rxrpc_local_rcu() firing because the
memory has been scheduled for RCU destruction whilst still queued:

rxrpc: Assertion failed
------------[ cut here ]------------
kernel BUG at net/rxrpc/local_object.c:468!

Note that if the processor comes around before the RCU free function, it
will just do nothing because ->dead is true.

Fix this by adding a separate refcount to count active users of the
endpoint that causes the endpoint to be destroyed when it reaches 0.

The original refcount can then be used to refcount objects through the work
processor and cause the memory to be rcu freed when that reaches 0.

Fixes: 4f95dd78a77e ("rxrpc: Rework local endpoint management")
Reported-by: syzbot+1e0edc4b8b7494c28450@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Fix send on a connected, but unbound socket

If sendmsg() or sendmmsg() is called on a connected socket that hasn't had
bind() called on it, then an oops will occur when the kernel tries to
connect the call because no local endpoint has been allocated.

Fix this by implicitly binding the socket if it is in the
RXRPC_CLIENT_UNBOUND state, just like it does for the RXRPC_UNBOUND state.

Further, the state should be transitioned to RXRPC_CLIENT_BOUND after this
to prevent further attempts to bind it.

This can be tested with:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <linux/rxrpc.h>
static const unsigned char inet6_addr[16] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 0xac, 0x14, 0x14, 0xaa
};
int main(void)
{
struct sockaddr_rxrpc srx;
struct cmsghdr *cm;
struct msghdr msg;
unsigned char control[16];
int fd;
memset(&srx, 0, sizeof(srx));
srx.srx_family = 0x21;
srx.srx_service = 0;
srx.transport_type = AF_INET;
srx.transport_len = 0x1c;
srx.transport.sin6.sin6_family = AF_INET6;
srx.transport.sin6.sin6_port = htons(0x4e22);
srx.transport.sin6.sin6_flowinfo = htons(0x4e22);
srx.transport.sin6.sin6_scope_id = htons(0xaa3b);
memcpy(&srx.transport.sin6.sin6_addr, inet6_addr, 16);
cm = (struct cmsghdr *)control;
cm->cmsg_len = CMSG_LEN(sizeof(unsigned long));
cm->cmsg_level = SOL_RXRPC;
cm->cmsg_type = RXRPC_USER_CALL_ID;
*(unsigned long *)CMSG_DATA(cm) = 0;
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_iov = NULL;
msg.msg_iovlen = 0;
msg.msg_control = control;
msg.msg_controllen = cm->cmsg_len;
msg.msg_flags = 0;
fd = socket(AF_RXRPC, SOCK_DGRAM, AF_INET);
connect(fd, (struct sockaddr *)&srx, sizeof(srx));
sendmsg(fd, &msg, 0);
return 0;
}

Leading to the following oops:

BUG: kernel NULL pointer dereference, address: 0000000000000018
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
...
RIP: 0010:rxrpc_connect_call+0x42/0xa01
...
Call Trace:
? mark_held_locks+0x47/0x59
? __local_bh_enable_ip+0xb6/0xba
rxrpc_new_client_call+0x3b1/0x762
? rxrpc_do_sendmsg+0x3c0/0x92e
rxrpc_do_sendmsg+0x3c0/0x92e
rxrpc_sendmsg+0x16b/0x1b5
sock_sendmsg+0x2d/0x39
___sys_sendmsg+0x1a4/0x22a
? release_sock+0x19/0x9e
? reacquire_held_locks+0x136/0x160
? release_sock+0x19/0x9e
? find_held_lock+0x2b/0x6e
? __lock_acquire+0x268/0xf73
? rxrpc_connect+0xdd/0xe4
? __local_bh_enable_ip+0xb6/0xba
__sys_sendmsg+0x5e/0x94
do_syscall_64+0x7d/0x1bf
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixes: 2341e0775747 ("rxrpc: Simplify connect() implementation and simplify sendmsg() op")
Reported-by: syzbot+7966f2a0b2c7da8939b4@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

rxrpc: Allow the kernel to mark a call as being non-interruptible

Allow kernel services using AF_RXRPC to indicate that a call should be
non-interruptible. This allows kafs to make things like lock-extension and
writeback data storage calls non-interruptible.

If this is set, signals will be ignored for operations on that call where
possible - such as waiting to get a call channel on an rxrpc connection.

It doesn't prevent UDP sendmsg from being interrupted, but that will be
handled by packet retransmission.

rxrpc_kernel_recv_data() isn't affected by this since that never waits,
preferring instead to return -EAGAIN and leave the waiting to the caller.

Userspace initiated calls can't be set to be uninterruptible at this time.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Provide kernel interface to set max lifespan on a call

Provide an interface to set max lifespan on a call from inside of the
kernel without having to call kernel_sendmsg().

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Make rxrpc_kernel_check_life() indicate if call completed

Make rxrpc_kernel_check_life() pass back the life counter through the
argument list and return true if the call has not yet completed.

Suggested-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Check address length before reading srx_service field

KMSAN will complain if valid address length passed to bind() is shorter
than sizeof(struct sockaddr_rxrpc) bytes.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

Revert "rxrpc: Allow failed client calls to be retried"

The changes introduced to allow rxrpc calls to be retried creates an issue
when it comes to refcounting afs_call structs. The problem is that when
rxrpc_send_data() queues the last packet for an asynchronous call, the
following sequence can occur:

(1) The notify_end_tx callback is invoked which causes the state in the
afs_call to be changed from AFS_CALL_CL_REQUESTING or
AFS_CALL_SV_REPLYING.

(2) afs_deliver_to_call() can then process event notifications from rxrpc
on the async_work queue.

(3) Delivery of events, such as an abort from the server, can cause the
afs_call state to be changed to AFS_CALL_COMPLETE on async_work.

(4) For an asynchronous call, afs_process_async_call() notes that the call
is complete and tried to clean up all the refs on async_work.

(5) rxrpc_send_data() might return the amount of data transferred
(success) or an error - which could in turn reflect a local error or a
received error.

Synchronising the clean up after rxrpc_kernel_send_data() returns an error
with the asynchronous cleanup is then tricky to get right.

Mostly revert commit c038a58ccfd6704d4d7d60ed3d6a0fca13cf13a4. The two API
functions the original commit added aren't currently used. This makes
rxrpc_kernel_send_data() always return successfully if it queued the data
it was given.

Note that this doesn't affect synchronous calls since their Rx notification
function merely pokes a wait queue and does not refcounting. The
asynchronous call notification function *has* to do refcounting and pass a
ref over the work item to avoid the need to sync the workqueue in call
cleanup.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Fix life check

The life-checking function, which is used by kAFS to make sure that a call
is still live in the event of a pending signal, only samples the received
packet serial number counter; it doesn't actually provoke a change in the
counter, rather relying on the server to happen to give us a packet in the
time window.

Fix this by adding a function to force a ping to be transmitted.

kAFS then keeps track of whether there's been a stall, and if so, uses the
new function to ping the server, resetting the timeout to allow the reply
to come back.

If there's a stall, a ping and the call is *still* stalled in the same
place after another period, then the call will be aborted.

Fixes: bc5e3a546d55 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Fixes: f4d15fb6f99a ("rxrpc: Provide functions for allowing cleaner handling of signals")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Revert "net: simplify sock_poll_wait"

This reverts commit dd979b4df817e9976f18fb6f9d134d6bc4a3c317.

This broke tcp_poll for SMC fallback: An AF_SMC socket establishes an
internal TCP socket for the initial handshake with the remote peer.
Whenever the SMC connection can not be established this TCP socket is
used as a fallback. All socket operations on the SMC socket are then
forwarded to the TCP socket. In case of poll, the file->private_data
pointer references the SMC socket because the TCP socket has no file
assigned. This causes tcp_poll to wait on the wrong socket.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Allow the reply time to be obtained on a client call

Allow the epoch value to be queried on a server connection. This is in the
rxrpc header of every packet for use in routing and is derived from the
client's state. It's also not supposed to change unless the client gets
restarted.

AFS can make use of this information to deduce whether a fileserver has
been restarted because the fileserver makes client calls to the filesystem
driver's cache manager to send notifications (ie. callback breaks) about
conflicting changes from other clients. These convey the fileserver's own
epoch value back to the filesystem.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Use IPv4 addresses throught the IPv6

AF_RXRPC opens an IPv6 socket through which to send and receive network
packets, both IPv6 and IPv4. It currently turns AF_INET addresses into
AF_INET-as-AF_INET6 addresses based on an assumption that this was
necessary; on further inspection of the code, however, it turns out that
the IPv6 code just farms packets aimed at AF_INET addresses out to the IPv4
code.

Fix AF_RXRPC to use AF_INET addresses directly when given them.

Fixes: 7b674e390e51 ("rxrpc: Fix IPv6 support")
Signed-off-by: David Howells <dhowells@redhat.com>

net: simplify sock_poll_wait

The wait_address argument is always directly derived from the filp
argument, so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Revert changes to convert to ->poll_mask() and aio IOCB_CMD_POLL

The poll() changes were not well thought out, and completely
unexplained. They also caused a huge performance regression, because
"->poll()" was no longer a trivial file operation that just called down
to the underlying file operations, but instead did at least two indirect
calls.

Indirect calls are sadly slow now with the Spectre mitigation, but the
performance problem could at least be largely mitigated by changing the
"->get_poll_head()" operation to just have a per-file-descriptor pointer
to the poll head instead. That gets rid of one of the new indirections.

But that doesn't fix the new complexity that is completely unwarranted
for the regular case. The (undocumented) reason for the poll() changes
was some alleged AIO poll race fixing, but we don't make the common case
slower and more complex for some uncommon special case, so this all
really needs way more explanations and most likely a fundamental
redesign.

[ This revert is a revert of about 30 different commits, not reverted
individually because that would just be unnecessarily messy - Linus ]

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

net/rxrpc: convert to ->poll_mask

Signed-off-by: Christoph Hellwig <hch@lst.de>

rxrpc: Fix the min security level for kernel calls

Fix the kernel call initiation to set the minimum security level for kernel
initiated calls (such as from kAFS) from the sockopt value.

Fixes: 19ffa01c9c45 ("rxrpc: Use structs to hold connection params and protocol info")
Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Fix leak of rxrpc_peer objects

When a new client call is requested, an rxrpc_conn_parameters struct object
is passed in with a bunch of parameters set, such as the local endpoint to
use. A pointer to the target peer record is also placed in there by
rxrpc_get_client_conn() - and this is removed if and only if a new
connection object is allocated. Thus it leaks if a new connection object
isn't allocated.

Fix this by putting any peer object attached to the rxrpc_conn_parameters
object in the function that allocated it.

Fixes: 19ffa01c9c45 ("rxrpc: Use structs to hold connection params and protocol info")
Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Fix firewall route keepalive

Fix the firewall route keepalive part of AF_RXRPC which is currently
function incorrectly by replying to VERSION REPLY packets from the server
with VERSION REQUEST packets.

Instead, send VERSION REPLY packets to the peers of service connections to
act as keep-alives 20s after the latest packet was transmitted to that
peer.

Also, just discard VERSION REPLY packets rather than replying to them.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc, afs: Use debug_ids rather than pointers in traces

In rxrpc and afs, use the debug_ids that are monotonically allocated to
various objects as they're allocated rather than pointers as kernel
pointers are now hashed making them less useful. Further, the debug ids
aren't reused anywhere nearly as quickly.

In addition, allow kernel services that use rxrpc, such as afs, to take
numbers from the rxrpc counter, assign them to their own call struct and
pass them in to rxrpc for both client and service calls so that the trace
lines for each will have the same ID tag.

Signed-off-by: David Howells <dhowells@redhat.com>

net: Use octal not symbolic permissions

Prefer the direct use of octal for permissions.

Done with checkpatch -f --types=SYMBOLIC_PERMS --fix-inplace
and some typing.

Miscellanea:

o Whitespace neatening around these conversions.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

rxrpc: Use correct netns source in rxrpc_release_sock()

In rxrpc_release_sock() there may be no rx->local value to access, so we
can't unconditionally follow it to the rxrpc network namespace information
to poke the connection reapers.

Instead, use the socket's namespace pointer to find the namespace.

This unfixed code causes the following static checker warning:

net/rxrpc/af_rxrpc.c:898 rxrpc_release_sock()
error: we previously assumed 'rx->local' could be null (see line 887)

Fixes: 3d18cbb7fd0c ("rxrpc: Fix conn expiry timers")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: annotate ->poll() instances

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

rxrpc: Fix conn expiry timers

Fix the rxrpc connection expiry timers so that connections for closed
AF_RXRPC sockets get deleted in a more timely fashion, freeing up the
transport UDP port much more quickly.

(1) Replace the delayed work items with work items plus timers so that
timer_reduce() can be used to shorten them and so that the timer
doesn't requeue the work item if the net namespace is dead.

(2) Don't use queue_delayed_work() as that won't alter the timeout if the
timer is already running.

(3) Don't rearm the timers if the network namespace is dead.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Fix service endpoint expiry

RxRPC service endpoints expire like they're supposed to by the following
means:

(1) Mark dead rxrpc_net structs (with ->live) rather than twiddling the
global service conn timeout, otherwise the first rxrpc_net struct to
die will cause connections on all others to expire immediately from
then on.

(2) Mark local service endpoints for which the socket has been closed
(->service_closed) so that the expiration timeout can be much
shortened for service and client connections going through that
endpoint.

(3) rxrpc_put_service_conn() needs to schedule the reaper when the usage
count reaches 1, not 0, as idle conns have a 1 count.

(4) The accumulator for the earliest time we might want to schedule for
should be initialised to jiffies + MAX_JIFFY_OFFSET, not ULONG_MAX as
the comparison functions use signed arithmetic.

(5) Simplify the expiration handling, adding the expiration value to the
idle timestamp each time rather than keeping track of the time in the
past before which the idle timestamp must go to be expired. This is
much easier to read.

(6) Ignore the timeouts if the net namespace is dead.

(7) Restart the service reaper work item rather the client reaper.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Split the call params from the operation params

When rxrpc_sendmsg() parses the control message buffer, it places the
parameters extracted into a structure, but lumps together call parameters
(such as user call ID) with operation parameters (such as whether to send
data, send an abort or accept a call).

Split the call parameters out into their own structure, a copy of which is
then embedded in the operation parameters struct.

The call parameters struct is then passed down into the places that need it
instead of passing the individual parameters. This allows for extra call
parameters to be added.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Lock around calling a kernel service Rx notification

Place a spinlock around the invocation of call->notify_rx() for a kernel
service call and lock again when ending the call and replace the
notification pointer with a pointer to a dummy function.

This is required because it's possible for rxrpc_notify_socket() to be
called after the call has been ended by the kernel service if called from
the asynchronous work function rxrpc_process_call().

However, rxrpc_notify_socket() currently only holds the RCU read lock when
invoking ->notify_rx(), which means that the afs_call struct would need to
be disposed of by call_rcu() rather than by kfree().

But we shouldn't see any notifications from a call after calling
rxrpc_kernel_end_call(), so a lock is required in rxrpc code.

Without this, we may see the call wait queue as having a corrupt spinlock:

BUG: spinlock bad magic on CPU#0, kworker/0:2/1612
general protection fault: 0000 [#1] SMP
...
Workqueue: krxrpcd rxrpc_process_call
task: ffff88040b83c400 task.stack: ffff88040adfc000
RIP: 0010:spin_bug+0x161/0x18f
RSP: 0018:ffff88040adffcc0 EFLAGS: 00010002
RAX: 0000000000000032 RBX: 6b6b6b6b6b6b6b6b RCX: ffffffff81ab16cf
RDX: ffff88041fa14c01 RSI: ffff88041fa0ccb8 RDI: ffff88041fa0ccb8
RBP: ffff88040adffcd8 R08: 00000000ffffffff R09: 00000000ffffffff
R10: ffff88040adffc60 R11: 000000000000022c R12: ffff88040aca2208
R13: ffffffff81a58114 R14: 0000000000000000 R15: 0000000000000000
....
Call Trace:
do_raw_spin_lock+0x1d/0x89
_raw_spin_lock_irqsave+0x3d/0x49
? __wake_up_common_lock+0x4c/0xa7
__wake_up_common_lock+0x4c/0xa7
? __lock_is_held+0x47/0x7a
__wake_up+0xe/0x10
afs_wake_up_call_waiter+0x11b/0x122 [kafs]
rxrpc_notify_socket+0x12b/0x258
rxrpc_process_call+0x18e/0x7d0
process_one_work+0x298/0x4de
? rescuer_thread+0x280/0x280
worker_thread+0x1d1/0x2ae
? rescuer_thread+0x280/0x280
kthread+0x12c/0x134
? kthread_create_on_node+0x3a/0x3a
ret_from_fork+0x27/0x40

In this case, note the corrupt data in EBX. The address of the offending
afs_call is in R12, plus the offset to the spinlock.

Signed-off-by: David Howells <dhowells@redhat.com>

net: rxrpc: mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Don't release call mutex on error pointer

Don't release call mutex at the end of rxrpc_kernel_begin_call() if the
call pointer actually holds an error value.

Fixes: 540b1c48c37a ("rxrpc: Fix deadlock between call creation and sendmsg/recvmsg")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Provide functions for allowing cleaner handling of signals

Provide a couple of functions to allow cleaner handling of signals in a
kernel service. They are:

(1) rxrpc_kernel_get_rtt()

This allows the kernel service to find out the RTT time for a call, so
as to better judge how large a timeout to employ.

Note, though, that whilst this returns a value in nanoseconds, the
timeouts can only actually be in jiffies.

(2) rxrpc_kernel_check_life()

This returns a number that is updated when ACKs are received from the
peer (notably including PING RESPONSE ACKs which we can elicit by
sending PING ACKs to see if the call still exists on the server).

The caller should compare the numbers of two calls to see if the call
is still alive.

These can be used to provide an extending timeout rather than returning
immediately in the case that a signal occurs that would otherwise abort an
RPC operation. The timeout would be extended if the server is still
responsive and the call is still apparently alive on the server.

For most operations this isn't that necessary - but for FS.StoreData it is:
OpenAFS writes the data to storage as it comes in without making a backup,
so if we immediately abort it when partially complete on a CTRL+C, say, we
have no idea of the state of the file after the abort.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Support service upgrade from a kernel service

Provide support for a kernel service to make use of the service upgrade
facility. This involves:

(1) Pass an upgrade request flag to rxrpc_kernel_begin_call().

(2) Make rxrpc_kernel_recv_data() return the call's current service ID so
that the caller can detect service upgrade and see what the service
was upgraded to.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Allow failed client calls to be retried

Allow a client call that failed on network error to be retried, provided
that the Tx queue still holds DATA packet 1. This allows an operation to
be submitted to another server or another address for the same server
without having to repackage and re-encrypt the data so far processed.

Two new functions are provided:

(1) rxrpc_kernel_check_call() - This is used to find out the completion
state of a call to guess whether it can be retried and whether it
should be retried.

(2) rxrpc_kernel_retry_call() - Disconnect the call from its current
connection, reset the state and submit it as a new client call to a
new address. The new address need not match the previous address.

A call may be retried even if all the data hasn't been loaded into it yet;
a partially constructed will be retained at the same point it was at when
an error condition was detected. msg_data_left() can be used to find out
how much data was packaged before the error occurred.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Remove some excess whitespace

Remove indentation from some blank lines.

Signed-off-by: David Howells <dhowells@redhat.com>

net: convert sock.sk_refcnt from atomic_t to refcount_t

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

This patch uses refcount_inc_not_zero() instead of
atomic_inc_not_zero_hint() due to absense of a _hint()
version of refcount API. If the hint() version must
be used, we might need to revisit API.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: convert sock.sk_wmem_alloc from atomic_t to refcount_t

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Provide a cmsg to specify the amount of Tx data for a call

Provide a control message that can be specified on the first sendmsg() of a
client call or the first sendmsg() of a service response to indicate the
total length of the data to be transmitted for that call.

Currently, because the length of the payload of an encrypted DATA packet is
encrypted in front of the data, the packet cannot be encrypted until we
know how much data it will hold.

By specifying the length at the beginning of the transmit phase, each DATA
packet length can be set before we start loading data from userspace (where
several sendmsg() calls may contribute to a particular packet).

An error will be returned if too little or too much data is presented in
the Tx phase.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Provide a getsockopt call to query what cmsgs types are supported

Provide a getsockopt() call that can query what cmsg types are supported by
AF_RXRPC.

rxrpc: Implement service upgrade

Implement AuriStor's service upgrade facility. There are three problems
that this is meant to deal with:

(1) Various of the standard AFS RPC calls have IPv4 addresses in their
requests and/or replies - but there's no room for including IPv6
addresses.

(2) Definition of IPv6-specific RPC operations in the standard operation
sets has not yet been achieved.

(3) One could envision the creation a new service on the same port that as
the original service. The new service could implement improved
operations - and the client could try this first, falling back to the
original service if it's not there.

Unfortunately, certain servers ignore packets addressed to a service
they don't implement and don't respond in any way - not even with an
ABORT. This means that the client must then wait for the call timeout
to occur.

What service upgrade does is to see if the connection is marked as being
'upgradeable' and if so, change the service ID in the server and thus the
request and reply formats. Note that the upgrade isn't mandatory - a
server that supports only the original call set will ignore the upgrade
request.

In the protocol, the procedure is then as follows:

(1) To request an upgrade, the first DATA packet in a new connection must
have the userStatus set to 1 (this is normally 0). The userStatus
value is normally ignored by the server.

(2) If the server doesn't support upgrading, the reply packets will
contain the same service ID as for the first request packet.

(3) If the server does support upgrading, all future reply packets on that
connection will contain the new service ID and the new service ID will
be applied to *all* further calls on that connection as well.

(4) The RPC op used to probe the upgrade must take the same request data
as the shadow call in the upgrade set (but may return a different
reply). GetCapability RPC ops were added to all standard sets for
just this purpose. Ops where the request formats differ cannot be
used for probing.

(5) The client must wait for completion of the probe before sending any
further RPC ops to the same destination. It should then use the
service ID that recvmsg() reported back in all future calls.

(6) The shadow service must have call definitions for all the operation
IDs defined by the original service.


To support service upgrading, a server should:

(1) Call bind() twice on its AF_RXRPC socket before calling listen().
Each bind() should supply a different service ID, but the transport
addresses must be the same. This allows the server to receive
requests with either service ID.

(2) Enable automatic upgrading by calling setsockopt(), specifying
RXRPC_UPGRADEABLE_SERVICE and passing in a two-member array of
unsigned shorts as the argument:

unsigned short optval[2];

This specifies a pair of service IDs. They must be different and must
match the service IDs bound to the socket. Member 0 is the service ID
to upgrade from and member 1 is the service ID to upgrade to.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Permit multiple service binding

Permit bind() to be called on an AF_RXRPC socket more than once (currently
maximum twice) to bind multiple listening services to it. There are some
restrictions:

(1) All bind() calls involved must have a non-zero service ID.

(2) The service IDs must all be different.

(3) The rest of the address (notably the transport part) must be the same
in all (a single UDP socket is shared).

(4) This must be done before listen() or sendmsg() is called.

This allows someone to connect to the service socket with different service
IDs and lays the foundation for service upgrading.

The service ID used by an incoming call can be extracted from the msg_name
returned by recvmsg().

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Separate the connection's protocol service ID from the lookup ID

Keep the rxrpc_connection struct's idea of the service ID that is exposed
in the protocol separate from the service ID that's used as a lookup key.

This allows the protocol service ID on a client connection to get upgraded
without making the connection unfindable for other client calls that also
would like to use the upgraded connection.

The connection's actual service ID is then returned through recvmsg() by
way of msg_name.

Whilst we're at it, we get rid of the last_service_id field from each
channel. The service ID is per-connection, not per-call and an entire
connection is upgraded in one go.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Support network namespacing

Support network namespacing in AF_RXRPC with the following changes:

(1) All the local endpoint, peer and call lists, locks, counters, etc. are
moved into the per-namespace record.

(2) All the connection tracking is moved into the per-namespace record
with the exception of the client connection ID tree, which is kept
global so that connection IDs are kept unique per-machine.

(3) Each namespace gets its own epoch. This allows each network namespace
to pretend to be a separate client machine.

(4) The /proc/net/rxrpc_xxx files are now called /proc/net/rxrpc/xxx and
the contents reflect the namespace.

fs/afs/ should be okay with this patch as it explicitly requires the current
net namespace to be init_net to permit a mount to proceed at the moment. It
will, however, need updating so that cells, IP addresses and DNS records are
per-namespace also.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Fix deadlock between call creation and sendmsg/recvmsg

All the routines by which rxrpc is accessed from the outside are serialised
by means of the socket lock (sendmsg, recvmsg, bind,
rxrpc_kernel_begin_call(), ...) and this presents a problem:

(1) If a number of calls on the same socket are in the process of
connection to the same peer, a maximum of four concurrent live calls
are permitted before further calls need to wait for a slot.

(2) If a call is waiting for a slot, it is deep inside sendmsg() or
rxrpc_kernel_begin_call() and the entry function is holding the socket
lock.

(3) sendmsg() and recvmsg() or the in-kernel equivalents are prevented
from servicing the other calls as they need to take the socket lock to
do so.

(4) The socket is stuck until a call is aborted and makes its slot
available to the waiter.

Fix this by:

(1) Provide each call with a mutex ('user_mutex') that arbitrates access
by the users of rxrpc separately for each specific call.

(2) Make rxrpc_sendmsg() and rxrpc_recvmsg() unlock the socket as soon as
they've got a call and taken its mutex.

Note that I'm returning EWOULDBLOCK from recvmsg() if MSG_DONTWAIT is
set but someone else has the lock. Should I instead only return
EWOULDBLOCK if there's nothing currently to be done on a socket, and
sleep in this particular instance because there is something to be
done, but we appear to be blocked by the interrupt handler doing its
ping?

(3) Make rxrpc_new_client_call() unlock the socket after allocating a new
call, locking its user mutex and adding it to the socket's call tree.
The call is returned locked so that sendmsg() can add data to it
immediately.

From the moment the call is in the socket tree, it is subject to
access by sendmsg() and recvmsg() - even if it isn't connected yet.

(4) Lock new service calls in the UDP data_ready handler (in
rxrpc_new_incoming_call()) because they may already be in the socket's
tree and the data_ready handler makes them live immediately if a user
ID has already been preassigned.

Note that the new call is locked before any notifications are sent
that it is live, so doing mutex_trylock() *ought* to always succeed.
Userspace is prevented from doing sendmsg() on calls that are in a
too-early state in rxrpc_do_sendmsg().

(5) Make rxrpc_new_incoming_call() return the call with the user mutex
held so that a ping can be scheduled immediately under it.

Note that it might be worth moving the ping call into
rxrpc_new_incoming_call() and then we can drop the mutex there.

(6) Make rxrpc_accept_call() take the lock on the call it is accepting and
release the socket after adding the call to the socket's tree. This
is slightly tricky as we've dequeued the call by that point and have
to requeue it.

Note that requeuing emits a trace event.

(7) Make rxrpc_kernel_send_data() and rxrpc_kernel_recv_data() take the
new mutex immediately and don't bother with the socket mutex at all.

This patch has the nice bonus that calls on the same socket are now to some
extent parallelisable.

Note that we might want to move rxrpc_service_prealloc() calls out from the
socket lock and give it its own lock, so that we don't hang progress in
other calls because we're waiting for the allocator.

We probably also want to avoid calling rxrpc_notify_socket() from within
the socket lock (rxrpc_accept_call()).

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marc Dionne <marc.c.dionne@auristor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Allow listen(sock, 0) to be used to disable listening

Allow listen() with a backlog of 0 to be used to disable listening on an
AF_RXRPC socket. This also releases any preallocation, thereby making it
easier for a kernel service to account for all allocated call structures
when shutting down the service.

The socket cannot thereafter have listening reenabled, but must rather be
closed and reopened.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: abstract away knowledge of IDR internals

Add idr_get_cursor() / idr_set_cursor() APIs, and remove the reference
to IDR_SIZE.

Link: http://lkml.kernel.org/r/1480369871-5271-65-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

rxrpc: Accesses of rxrpc_local::service need to be RCU managed

struct rxrpc_local->service is marked __rcu - this means that accesses of
it need to be managed using RCU wrappers. There are two such places in
rxrpc_release_sock() where the value is checked and cleared. Fix this by
using the appropriate wrappers.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Reduce the rxrpc_local::services list to a pointer

Reduce the rxrpc_local::services list to just a pointer as we don't permit
multiple service endpoints to bind to a single transport endpoints (this is
excluded by rxrpc_lookup_local()).

The reason we don't allow this is that if you send a request to an AFS
filesystem service, it will try to talk back to your cache manager on the
port you sent from (this is how file change notifications are handled). To
prevent someone from stealing your CM callbacks, we don't let AF_RXRPC
sockets share a UDP socket if at least one of them has a service bound.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Improve skb tracing

Improve sk_buff tracing within AF_RXRPC by the following means:

(1) Use an enum to note the event type rather than plain integers and use
an array of event names rather than a big multi ?: list.

(2) Distinguish Rx from Tx packets and account them separately. This
requires the call phase to be tracked so that we know what we might
find in rxtx_buffer[].

(3) Add a parameter to rxrpc_{new,see,get,free}_skb() to indicate the
event type.

(4) A pair of 'rotate' events are added to indicate packets that are about
to be rotated out of the Rx and Tx windows.

(5) A pair of 'lost' events are added, along with rxrpc_lose_skb() for
packet loss injection recording.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Make IPv6 support conditional on CONFIG_IPV6

Add CONFIG_AF_RXRPC_IPV6 and make the IPv6 support code conditional on it.
This is then made conditional on CONFIG_IPV6.

Without this, the following can be seen:

net/built-in.o: In function `rxrpc_init_peer':
>> peer_object.c:(.text+0x18c3c8): undefined reference to `ip6_route_output_flags'

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Add IPv6 support

Add IPv6 support to AF_RXRPC. With this, AF_RXRPC sockets can be created:

service = socket(AF_RXRPC, SOCK_DGRAM, PF_INET6);

instead of:

service = socket(AF_RXRPC, SOCK_DGRAM, PF_INET);

The AFS filesystem doesn't support IPv6 at the moment, though, since that
requires upgrades to some of the RPC calls.

Note that a good portion of this patch is replacing "%pI4:%u" in print
statements with "%pISpc" which is able to handle both protocols and print
the port.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Create an address for sendmsg() to bind unbound socket with

Create an address for sendmsg() to bind unbound socket with rather than
using a completely blank address otherwise the transport socket creation
will fail because it will try to use address family 0.

We use the address family specified in the protocol argument when the
AF_RXRPC socket was created and SOCK_DGRAM as the default. For anything
else, bind() must be used.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Adjust the call ref tracepoint to show kernel API refs

Adjust the call ref tracepoint to show references held on a call by the
kernel API separately as much as possible and add an additional trace to at
the allocation point from the preallocation buffer for an incoming call.

Note that this doesn't show the allocation of a client call for the kernel
separately at the moment.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Rewrite the data and ack handling code

Rewrite the data and ack handling code such that:

(1) Parsing of received ACK and ABORT packets and the distribution and the
filing of DATA packets happens entirely within the data_ready context
called from the UDP socket. This allows us to process and discard ACK
and ABORT packets much more quickly (they're no longer stashed on a
queue for a background thread to process).

(2) We avoid calling skb_clone(), pskb_pull() and pskb_trim(). We instead
keep track of the offset and length of the content of each packet in
the sk_buff metadata. This means we don't do any allocation in the
receive path.

(3) Jumbo DATA packet parsing is now done in data_ready context. Rather
than cloning the packet once for each subpacket and pulling/trimming
it, we file the packet multiple times with an annotation for each
indicating which subpacket is there. From that we can directly
calculate the offset and length.

(4) A call's receive queue can be accessed without taking locks (memory
barriers do have to be used, though).

(5) Incoming calls are set up from preallocated resources and immediately
made live. They can than have packets queued upon them and ACKs
generated. If insufficient resources exist, DATA packet #1 is given a
BUSY reply and other DATA packets are discarded).

(6) sk_buffs no longer take a ref on their parent call.

To make this work, the following changes are made:

(1) Each call's receive buffer is now a circular buffer of sk_buff
pointers (rxtx_buffer) rather than a number of sk_buff_heads spread
between the call and the socket. This permits each sk_buff to be in
the buffer multiple times. The receive buffer is reused for the
transmit buffer.

(2) A circular buffer of annotations (rxtx_annotations) is kept parallel
to the data buffer. Transmission phase annotations indicate whether a
buffered packet has been ACK'd or not and whether it needs
retransmission.

Receive phase annotations indicate whether a slot holds a whole packet
or a jumbo subpacket and, if the latter, which subpacket. They also
note whether the packet has been decrypted in place.

(3) DATA packet window tracking is much simplified. Each phase has just
two numbers representing the window (rx_hard_ack/rx_top and
tx_hard_ack/tx_top).

The hard_ack number is the sequence number before base of the window,
representing the last packet the other side says it has consumed.
hard_ack starts from 0 and the first packet is sequence number 1.

The top number is the sequence number of the highest-numbered packet
residing in the buffer. Packets between hard_ack+1 and top are
soft-ACK'd to indicate they've been received, but not yet consumed.

Four macros, before(), before_eq(), after() and after_eq() are added
to compare sequence numbers within the window. This allows for the
top of the window to wrap when the hard-ack sequence number gets close
to the limit.

Two flags, RXRPC_CALL_RX_LAST and RXRPC_CALL_TX_LAST, are added also
to indicate when rx_top and tx_top point at the packets with the
LAST_PACKET bit set, indicating the end of the phase.

(4) Calls are queued on the socket 'receive queue' rather than packets.
This means that we don't need have to invent dummy packets to queue to
indicate abnormal/terminal states and we don't have to keep metadata
packets (such as ABORTs) around

(5) The offset and length of a (sub)packet's content are now passed to
the verify_packet security op. This is currently expected to decrypt
the packet in place and validate it.

However, there's now nowhere to store the revised offset and length of
the actual data within the decrypted blob (there may be a header and
padding to skip) because an sk_buff may represent multiple packets, so
a locate_data security op is added to retrieve these details from the
sk_buff content when needed.

(6) recvmsg() now has to handle jumbo subpackets, where each subpacket is
individually secured and needs to be individually decrypted. The code
to do this is broken out into rxrpc_recvmsg_data() and shared with the
kernel API. It now iterates over the call's receive buffer rather
than walking the socket receive queue.

Additional changes:

(1) The timers are condensed to a single timer that is set for the soonest
of three timeouts (delayed ACK generation, DATA retransmission and
call lifespan).

(2) Transmission of ACK and ABORT packets is effected immediately from
process-context socket ops/kernel API calls that cause them instead of
them being punted off to a background work item. The data_ready
handler still has to defer to the background, though.

(3) A shutdown op is added to the AF_RXRPC socket so that the AFS
filesystem can shut down the socket and flush its own work items
before closing the socket to deal with any in-progress service calls.

Future additional changes that will need to be considered:

(1) Make sure that a call doesn't hog the front of the queue by receiving
data from the network as fast as userspace is consuming it to the
exclusion of other calls.

(2) Transmit delayed ACKs from within recvmsg() when we've consumed
sufficiently more packets to avoid the background work item needing to
run.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Preallocate peers, conns and calls for incoming service requests

Make it possible for the data_ready handler called from the UDP transport
socket to completely instantiate an rxrpc_call structure and make it
immediately live by preallocating all the memory it might need. The idea
is to cut out the background thread usage as much as possible.

[Note that the preallocated structs are not actually used in this patch -
that will be done in a future patch.]

If insufficient resources are available in the preallocation buffers, it
will be possible to discard the DATA packet in the data_ready handler or
schedule a BUSY packet without the need to schedule an attempt at
allocation in a background thread.

To this end:

(1) Preallocate rxrpc_peer, rxrpc_connection and rxrpc_call structs to a
maximum number each of the listen backlog size. The backlog size is
limited to a maxmimum of 32. Only this many of each can be in the
preallocation buffer.

(2) For userspace sockets, the preallocation is charged initially by
listen() and will be recharged by accepting or rejecting pending
new incoming calls.

(3) For kernel services {,re,dis}charging of the preallocation buffers is
handled manually. Two notifier callbacks have to be provided before
kernel_listen() is invoked:

(a) An indication that a new call has been instantiated. This can be
used to trigger background recharging.

(b) An indication that a call is being discarded. This is used when
the socket is being released.

A function, rxrpc_kernel_charge_accept() is called by the kernel
service to preallocate a single call. It should be passed the user ID
to be used for that call and a callback to associate the rxrpc call
with the kernel service's side of the ID.

(4) Discard the preallocation when the socket is closed.

(5) Temporarily bump the refcount on the call allocated in
rxrpc_incoming_call() so that rxrpc_release_call() can ditch the
preallocation ref on service calls unconditionally. This will no
longer be necessary once the preallocation is used.

Note that this does not yet control the number of active service calls on a
client - that will come in a later patch.

A future development would be to provide a setsockopt() call that allows a
userspace server to manually charge the preallocation buffer. This would
allow user call IDs to be provided in advance and the awkward manual accept
stage to be bypassed.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Convert rxrpc_local::services to an hlist

Convert the rxrpc_local::services list to an hlist so that it can be
accessed under RCU conditions more readily.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Calls shouldn't hold socket refs

rxrpc calls shouldn't hold refs on the sock struct. This was done so that
the socket wouldn't go away whilst the call was in progress, such that the
call could reach the socket's queues.

However, we can mark the socket as requiring an RCU release and rely on the
RCU read lock.

To make this work, we do:

(1) rxrpc_release_call() removes the call's call user ID. This is now
only called from socket operations and not from the call processor:

rxrpc_accept_call() / rxrpc_kernel_accept_call()
rxrpc_reject_call() / rxrpc_kernel_reject_call()
rxrpc_kernel_end_call()
rxrpc_release_calls_on_socket()
rxrpc_recvmsg()

Though it is also called in the cleanup path of
rxrpc_accept_incoming_call() before we assign a user ID.

(2) Pass the socket pointer into rxrpc_release_call() rather than getting
it from the call so that we can get rid of uninitialised calls.

(3) Fix call processor queueing to pass a ref to the work queue and to
release that ref at the end of the processor function (or to pass it
back to the work queue if we have to requeue).

(4) Skip out of the call processor function asap if the call is complete
and don't requeue it if the call is complete.

(5) Clean up the call immediately that the refcount reaches 0 rather than
trying to defer it. Actual deallocation is deferred to RCU, however.

(6) Don't hold socket refs for allocated calls.

(7) Use the RCU read lock when queueing a message on a socket and treat
the call's socket pointer according to RCU rules and check it for
NULL.

We also need to use the RCU read lock when viewing a call through
procfs.

(8) Transmit the final ACK/ABORT to a client call in rxrpc_release_call()
if this hasn't been done yet so that we can then disconnect the call.
Once the call is disconnected, it won't have any access to the
connection struct and the UDP socket for the call work processor to be
able to send the ACK. Terminal retransmission will be handled by the
connection processor.

(9) Release all calls immediately on the closing of a socket rather than
trying to defer this. Incomplete calls will be aborted.

The call refcount model is much simplified. Refs are held on the call by:

(1) A socket's user ID tree.

(2) A socket's incoming call secureq and acceptq.

(3) A kernel service that has a call in progress.

(4) A queued call work processor. We have to take care to put any call
that we failed to queue.

(5) sk_buffs on a socket's receive queue. A future patch will get rid of
this.

Whilst we're at it, we can do:

(1) Get rid of the RXRPC_CALL_EV_RELEASE event. Release is now done
entirely from the socket routines and never from the call's processor.

(2) Get rid of the RXRPC_CALL_DEAD state. Calls now end in the
RXRPC_CALL_COMPLETE state.

(3) Get rid of the rxrpc_call::destroyer work item. Calls are now torn
down when their refcount reaches 0 and then handed over to RCU for
final cleanup.

(4) Get rid of the rxrpc_call::deadspan timer. Calls are cleaned up
immediately they're finished with and don't hang around.
Post-completion retransmission is handled by the connection processor
once the call is disconnected.

(5) Get rid of the dead call expiry setting as there's no longer a timer
to set.

(6) rxrpc_destroy_all_calls() can just check that the call list is empty.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Improve the call tracking tracepoint

Improve the call tracking tracepoint by showing more differentiation
between some of the put and get events, including:

(1) Getting and putting refs for the socket call user ID tree.

(2) Getting and putting refs for queueing and failing to queue the call
processor work item.

Note that these aren't necessarily used in this patch, but will be taken
advantage of in future patches.

An enum is added for the event subtype numbers rather than coding them
directly as decimal numbers and a table of 3-letter strings is provided
rather than a sequence of ?: operators.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Randomise epoch and starting client conn ID values

Create a random epoch value rather than a time-based one on startup and set
the top bit to indicate that this is the case.

Also create a random starting client connection ID value. This will be
incremented from here as new client connections are created.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Don't expose skbs to in-kernel users [ver #2]

Don't expose skbs to in-kernel users, such as the AFS filesystem, but
instead provide a notification hook the indicates that a call needs
attention and another that indicates that there's a new call to be
collected.

This makes the following possibilities more achievable:

(1) Call refcounting can be made simpler if skbs don't hold refs to calls.

(2) skbs referring to non-data events will be able to be freed much sooner
rather than being queued for AFS to pick up as rxrpc_kernel_recv_data
will be able to consult the call state.

(3) We can shortcut the receive phase when a call is remotely aborted
because we don't have to go through all the packets to get to the one
cancelling the operation.

(4) It makes it easier to do encryption/decryption directly between AFS's
buffers and sk_buffs.

(5) Encryption/decryption can more easily be done in the AFS's thread
contexts - usually that of the userspace process that issued a syscall
- rather than in one of rxrpc's background threads on a workqueue.

(6) AFS will be able to wait synchronously on a call inside AF_RXRPC.

To make this work, the following interface function has been added:

int rxrpc_kernel_recv_data(
struct socket *sock, struct rxrpc_call *call,
void *buffer, size_t bufsize, size_t *_offset,
bool want_more, u32 *_abort_code);

This is the recvmsg equivalent. It allows the caller to find out about the
state of a specific call and to transfer received data into a buffer
piecemeal.

afs_extract_data() and rxrpc_kernel_recv_data() now do all the extraction
logic between them. They don't wait synchronously yet because the socket
lock needs to be dealt with.

Five interface functions have been removed:

rxrpc_kernel_is_data_last()
rxrpc_kernel_get_abort_code()
rxrpc_kernel_get_error_number()
rxrpc_kernel_free_skb()
rxrpc_kernel_data_consumed()

As a temporary hack, sk_buffs going to an in-kernel call are queued on the
rxrpc_call struct (->knlrecv_queue) rather than being handed over to the
in-kernel user. To process the queue internally, a temporary function,
temp_deliver_data() has been added. This will be replaced with common code
between the rxrpc_recvmsg() path and the kernel_rxrpc_recv_data() path in a
future patch.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Pass struct socket * to more rxrpc kernel interface functions

Pass struct socket * to more rxrpc kernel interface functions. They should
be starting from this rather than the socket pointer in the rxrpc_call
struct if they need to access the socket.

I have left:

rxrpc_kernel_is_data_last()
rxrpc_kernel_get_abort_code()
rxrpc_kernel_get_error_number()
rxrpc_kernel_free_skb()
rxrpc_kernel_data_consumed()

unmodified as they're all about to be removed (and, in any case, don't
touch the socket).

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Use a tracepoint for skb accounting debugging

Use a tracepoint to log various skb accounting points to help in debugging
refcounting errors.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Fix error handling in af_rxrpc_init()

security initialized after alloc workqueue, so we should exit security
before destroy workqueue in the error handing.

Fixes: 648af7fca159 ("rxrpc: Absorb the rxkad security module")
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Add RCU destruction for connections and calls

Add RCU destruction for connections and calls as the RCU lookup from the
transport socket data_ready handler is going to come along shortly.

Whilst we're at it, move the cleanup workqueue flushing and RCU barrierage
into the destruction code for the objects that need it (locals and
connections) and add the extra RCU barrier required for connection cleanup.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Check that the client conns cache is empty before module removal

Check that the client conns cache is empty before module removal and bug if
not, listing any offending connections that are still present. Unfortunately,
if there are connections still around, then the transport socket is still
unexpectedly open and active, so we can't just unallocate the connections.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Kill off the rxrpc_transport struct

The rxrpc_transport struct is now redundant, given that the rxrpc_peer
struct is now per peer port rather than per peer host, so get rid of it.

Service connection lists are transferred to the rxrpc_peer struct, as is
the conn_lock. Previous patches moved the client connection handling out
of the rxrpc_transport struct and discarded the connection bundling code.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Kill the client connection bundle concept

Kill off the concept of maintaining a bundle of connections to a particular
target service to increase the number of call slots available for any
beyond four for that service (there are four call slots per connection).

This will make cleaning up the connection handling code easier and
facilitate removal of the rxrpc_transport struct. Bundling can be
reintroduced later if necessary.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Provide more refcount helper functions

Provide refcount helper functions for connections so that the code doesn't
touch local or connection usage counts directly.

Also make it such that local and peer put functions can take a NULL
pointer.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Validate the net address given to rxrpc_kernel_begin_call()

Validate the net address given to rxrpc_kernel_begin_call() before using
it.

Whilst this should be mostly unnecessary for in-kernel users, it does clear
the tail of the address struct in case we want to hash or compare the whole
thing.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Use IDR to allocate client conn IDs on a machine-wide basis

Use the IDR facility to allocate client connection IDs on a machine-wide
basis so that each client connection has a unique identifier. When the
connection ID space wraps, we advance the epoch by 1, thereby effectively
having a 62-bit ID space. The IDR facility is then used to look up client
connections during incoming packet routing instead of using an rbtree
rooted on the transport.

This change allows for the removal of the transport in the future and also
means that client connections can be looked up directly in the data-ready
handler by connection ID.

The ID management code is placed in a new file, conn-client.c, to which all
the client connection-specific code will eventually move.

Note that the IDR tree gets very expensive on memory if the connection IDs
are widely scattered throughout the number space, so we shall need to
retire connections that have, say, an ID more than four times the maximum
number of client conns away from the current allocation point to try and
keep the IDs concentrated. We will also need to retire connections from an
old epoch.

Also note that, for the moment, a pointer to the transport has to be passed
through into the ID allocation function so that we can take a BH lock to
prevent a locking issue against in-BH lookup of client connections. This
will go away later when RCU is used for server connections also.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Fix exclusive connection handling

"Exclusive connections" are meant to be used for a single client call and
then scrapped. The idea is to limit the use of the negotiated security
context. The current code, however, isn't doing this: it is instead
restricting the socket to a single virtual connection and doing all the
calls over that.

This is changed such that the socket no longer maintains a special virtual
connection over which it will do all the calls, but rather gets a new one
each time a new exclusive call is made.

Further, using a socket option for this is a poor choice. It should be
done on sendmsg with a control message marker instead so that calls can be
marked exclusive individually. To that end, add RXRPC_EXCLUSIVE_CALL
which, if passed to sendmsg() as a control message element, will cause the
call to be done on an single-use connection.

The socket option (RXRPC_EXCLUSIVE_CONNECTION) still exists and, if set,
will override any lack of RXRPC_EXCLUSIVE_CALL being specified so that
programs using the setsockopt() will appear to work the same.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Use structs to hold connection params and protocol info

Define and use a structure to hold connection parameters. This makes it
easier to pass multiple connection parameters around.

Define and use a structure to hold protocol information used to hash a
connection for lookup on incoming packet. Most of these fields will be
disposed of eventually, including the duplicate local pointer.

Whilst we're at it rename "proto" to "family" when referring to a protocol
family.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: checking for IS_ERR() instead of NULL

rxrpc_lookup_peer_rcu() and rxrpc_lookup_peer() return NULL on error, never
error pointers, so IS_ERR() can't be used.

Fix three callers of those functions.

Fixes: be6e6707f6ee ('rxrpc: Rework peer object handling to use hash table and RCU')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Rework local endpoint management

Rework the local RxRPC endpoint management.

Local endpoint objects are maintained in a flat list as before. This
should be okay as there shouldn't be more than one per open AF_RXRPC socket
(there can be fewer as local endpoints can be shared if their local service
ID is 0 and they share the same local transport parameters).

Changes:

(1) Local endpoints may now only be shared if they have local service ID 0
(ie. they're not being used for listening).

This prevents a scenario where process A is listening of the Cache
Manager port and process B contacts a fileserver - which may then
attempt to send CM requests back to B. But if A and B are sharing a
local endpoint, A will get the CM requests meant for B.

(2) We use a mutex to handle lookups and don't provide RCU-only lookups
since we only expect to access the list when opening a socket or
destroying an endpoint.

The local endpoint object is pointed to by the transport socket's
sk_user_data for the life of the transport socket - allowing us to
refer to it directly from the sk_data_ready and sk_error_report
callbacks.

(3) atomic_inc_not_zero() now exists and can be used to only share a local
endpoint if the last reference hasn't yet gone.

(4) We can remove rxrpc_local_lock - a spinlock that had to be taken with
BH processing disabled given that we assume sk_user_data won't change
under us.

(5) The transport socket is shut down before we clear the sk_user_data
pointer so that we can be sure that the transport socket's callbacks
won't be invoked once the RCU destruction is scheduled.

(6) Local endpoints have a work item that handles both destruction and
event processing. The means that destruction doesn't then need to
wait for event processing. The event queues can then be cleared after
the transport socket is shut down.

(7) Local endpoints are no longer available for resurrection beyond the
life of the sockets that had them open. As soon as their last ref
goes, they are scheduled for destruction and may not have their usage
count moved from 0.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Rework peer object handling to use hash table and RCU

Rework peer object handling to use a hash table instead of a flat list and
to use RCU. Peer objects are no longer destroyed by passing them to a
workqueue to process, but rather are just passed to the RCU garbage
collector as kfree'able objects.

The hash function uses the local endpoint plus all the components of the
remote address, except for the RxRPC service ID. Peers thus represent a
UDP port on the remote machine as contacted by a UDP port on this machine.

The RCU read lock is used to handle non-creating lookups so that they can
be called from bottom half context in the sk_error_report handler without
having to lock the hash table against modification.
rxrpc_lookup_peer_rcu() *does* take a reference on the peer object as in
the future, this will be passed to a work item for error distribution in
the error_report path and this function will cease being used in the
data_ready path.

Creating lookups are done under spinlock rather than mutex as they might be
set up due to an external stimulus if the local endpoint is a server.

Captured network error messages (ICMP) are handled with respect to this
struct and MTU size and RTT are cached here.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Limit the listening backlog

Limit the socket incoming call backlog queue size so that a remote client
can't pump in sufficient new calls that the server runs out of memory. Note
that this is partially theoretical at the moment since whilst the number of
calls is limited, the number of packets trying to set up new calls is not.
This will be addressed in a later patch.

If the caller of listen() specifies a backlog INT_MAX, then they get the
current maximum; anything else greater than max_backlog or anything
negative incurs EINVAL.

The limit on the maximum queue size can be set by:

echo N >/proc/sys/net/rxrpc/max_backlog

where 4<=N<=32.

Further, set the default backlog to 0, requiring listen() to be called
before we start actually queueing new calls. Whilst this kind of is a
change in the UAPI, the caller can't actually *accept* new calls anyway
unless they've first called listen() to put the socket into the LISTENING
state - thus the aforementioned new calls would otherwise just sit there,
eating up kernel memory. (Note that sockets that don't have a non-zero
service ID bound don't get incoming calls anyway.)

Given that the default backlog is now 0, make the AFS filesystem call
kernel_listen() to set the maximum backlog for itself.

Possible improvements include:

(1) Trimming a too-large backlog to max_backlog when listen is called.

(2) Trimming the backlog value whenever the value is used so that changes
to max_backlog are applied to an open socket automatically. Note that
the AFS filesystem opens one socket and keeps it open for extended
periods, so would miss out on changes to max_backlog.

(3) Having a separate setting for the AFS filesystem.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Simplify connect() implementation and simplify sendmsg() op

Simplify the RxRPC connect() implementation. It will just note the
destination address it is given, and if a sendmsg() comes along with no
address, this will be assigned as the address. No transport struct will be
held internally, which will allow us to remove this later.

Simplify sendmsg() also. Whilst a call is active, userspace refers to it
by a private unique user ID specified in a control message. When sendmsg()
sees a user ID that doesn't map to an extant call, it creates a new call
for that user ID and attempts to add it. If, when we try to add it, the
user ID is now registered, we now reject the message with -EEXIST. We
should never see this situation unless two threads are racing, trying to
create a call with the same ID - which would be an error.

It also isn't required to provide sendmsg() with an address - provided the
control message data holds a user ID that maps to a currently active call.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Use pr_<level> and pr_fmt, reduce object size a few KB

Use the more common kernel logging style and reduce object size.

The logging message prefix changes from a mixture of
"RxRPC:" and "RXRPC:" to "af_rxrpc: ".

$ size net/rxrpc/built-in.o*
text data bss dec hex filename
64172 1972 8304 74448 122d0 net/rxrpc/built-in.o.new
67512 1972 8304 77788 12fdc net/rxrpc/built-in.o.old

Miscellanea:

o Consolidate the ASSERT macros to use a single pr_err call with
decimal and hexadecimal output and a stringified #OP argument

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Absorb the rxkad security module

Absorb the rxkad security module into the af_rxrpc module so that there's
only one module file. This avoids a circular dependency whereby rxkad pins
af_rxrpc and cached connections pin rxkad but can't be manually evicted
(they will expire eventually and cease pinning).

With this change, af_rxrpc can just be unloaded, despite having cached
connections.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Replace all unsigned with unsigned int

Replace all "unsigned" types with "unsigned int" types.

Reported-by: David Miller <davem@davemloft.net>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Clear the unused part of a sockaddr_rxrpc for memcmp() use

Clear the unused part of a sockaddr_rxrpc structs so that memcmp() can be
used to compare them.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Adjust some whitespace and comments

Remove some excess whitespace, insert some missing spaces and adjust a
couple of comments.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: The protocol family should be set to PF_RXRPC not PF_UNIX

Fix the protocol family set in the proto_ops for rxrpc to be PF_RXRPC not
PF_UNIX.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Keep the skb private record of the Rx header in host byte order

Currently, a copy of the Rx packet header is copied into the the sk_buff
private data so that we can advance the pointer into the buffer,
potentially discarding the original. At the moment, this copy is held in
network byte order, but this means we're doing a lot of unnecessary
translations.

The reasons it was done this way are that we need the values in network
byte order occasionally and we can use the copy, slightly modified, as part
of an iov array when sending an ack or an abort packet.

However, it seems more reasonable on review that it would be better kept in
host byte order and that we make up a new header when we want to send
another packet.

To this end, rename the original header struct to rxrpc_wire_header (with
BE fields) and institute a variant called rxrpc_host_header that has host
order fields. Change the struct in the sk_buff private data into an
rxrpc_host_header and translate the values when filling it in.

This further allows us to keep values kept in various structures in host
byte order rather than network byte order and allows removal of some fields
that are byteswapped duplicates.

Signed-off-by: David Howells <dhowells@redhat.com>

net: Generalise wq_has_sleeper helper

The memory barrier in the helper wq_has_sleeper is needed by just
about every user of waitqueue_active. This patch generalises it
by making it take a wait_queue_head_t directly. The existing
helper is renamed to skwq_has_sleeper.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

KEYS: Merge the type-specific data with the payload data

Merge the type-specific data with the payload data into one four-word chunk
as it seems pointless to keep them separate.

Use user_key_payload() for accessing the payloads of overloaded
user-defined keys.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cifs@vger.kernel.org
cc: ecryptfs@vger.kernel.org
cc: linux-ext4@vger.kernel.org
cc: linux-f2fs-devel@lists.sourceforge.net
cc: linux-nfs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: linux-ima-devel@lists.sourceforge.net

net: Pass kern from net_proto_family.create to sk_alloc

In preparation for changing how struct net is refcounted
on kernel sockets pass the knowledge that we are creating
a kernel socket from sock_create_kern through to sk_alloc.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Remove iocb argument from sendmsg and recvmsg

After TIPC doesn't depend on iocb argument in its internal
implementations of sendmsg() and recvmsg() hooks defined in proto
structure, no any user is using iocb argument in them at all now.
Then we can drop the redundant iocb argument completely from kinds of
implementations of both sendmsg() and recvmsg() in the entire
networking stack.

Cc: Christoph Hellwig <hch@lst.de>
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

af_rxrpc: Add sysctls for configuring RxRPC parameters

Add sysctls for configuring RxRPC protocol handling, specifically controls on
delays before ack generation, the delay before resending a packet, the maximum
lifetime of a call and the expiration times of calls, connections and
transports that haven't been recently used.

More info added in Documentation/networking/rxrpc.txt.

Signed-off-by: David Howells <dhowells@redhat.com>

net: proc: change proc_net_remove to remove_proc_entry

proc_net_remove is only used to remove proc entries
that under /proc/net,it's not a general function for
removing proc entries of netns. if we want to remove
some proc entries which under /proc/net/stat/, we still
need to call remove_proc_entry.

this patch use remove_proc_entry to replace proc_net_remove.
we can remove proc_net_remove after this patch.

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: proc: change proc_net_fops_create to proc_create

Right now, some modules such as bonding use proc_create
to create proc entries under /proc/net/, and other modules
such as ipv4 use proc_net_fops_create.

It looks a little chaos.this patch changes all of
proc_net_fops_create to proc_create. we can remove
proc_net_fops_create after this patch.

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Use FIELD_SIZEOF() in af_rxrpc_init().

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: cleanup unsigned to unsigned int

Use of "unsigned int" is preferred to bare "unsigned" in net tree.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: rxrpc_workqueue isn't used during memory reclaim

rxrpc_workqueue isn't depended upon while reclaiming memory. Convert
to alloc_workqueue() without WQ_MEM_RECLAIM.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: linux-afs@lists.infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

net: sock_def_readable() and friends RCU conversion

sk_callback_lock rwlock actually protects sk->sk_sleep pointer, so we
need two atomic operations (and associated dirtying) per incoming
packet.

RCU conversion is pretty much needed :

1) Add a new structure, called "struct socket_wq" to hold all fields
that will need rcu_read_lock() protection (currently: a
wait_queue_head_t and a struct fasync_struct pointer).

[Future patch will add a list anchor for wakeup coalescing]

2) Attach one of such structure to each "struct socket" created in
sock_alloc_inode().

3) Respect RCU grace period when freeing a "struct socket_wq"

4) Change sk_sleep pointer in "struct sock" by sk_wq, pointer to "struct
socket_wq"

5) Change sk_sleep() function to use new sk->sk_wq instead of
sk->sk_sleep

6) Change sk_has_sleeper() to wq_has_sleeper() that must be used inside
a rcu_read_lock() section.

7) Change all sk_has_sleeper() callers to :
- Use rcu_read_lock() instead of read_lock(&sk->sk_callback_lock)
- Use wq_has_sleeper() to eventually wakeup tasks.
- Use rcu_read_unlock() instead of read_unlock(&sk->sk_callback_lock)

8) sock_wake_async() is modified to use rcu protection as well.

9) Exceptions :
macvtap, drivers/net/tun.c, af_unix use integrated "struct socket_wq"
instead of dynamically allocated ones. They dont need rcu freeing.

Some cleanups or followups are probably needed, (possible
sk_callback_lock conversion to a spinlock for example...).

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sk_sleep() helper

Define a new function to return the waitqueue of a "struct sock".

static inline wait_queue_head_t *sk_sleep(struct sock *sk)
{
return sk->sk_sleep;
}

Change all read occurrences of sk_sleep by a call to this function.

Needed for a future RCU conversion. sk_sleep wont be a field directly
available.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

net: use net_eq to compare nets

Generated with the following semantic patch

@@
struct net *n1;
struct net *n2;
@@
- n1 == n2
+ net_eq(n1, n2)

@@
struct net *n1;
struct net *n2;
@@
- n1 != n2
+ !net_eq(n1, n2)

applied over {include,net,drivers/net}.

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: pass kern to net_proto_family create function

The generic __sock_create function has a kern argument which allows the
security system to make decisions based on if a socket is being created by
the kernel or by userspace. This patch passes that flag to the
net_proto_family specific create function, so it can do the same thing.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mark net_proto_ops as const

All usages of structure net_proto_ops should be declared const.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Make setsockopt() optlen be unsigned.

This provides safety against negative optlen at the type
level instead of depending upon (sometimes non-trivial)
checks against this sprinkled all over the the place, in
each and every implementation.

Based upon work done by Arjan van de Ven and feedback
from Linus Torvalds.

Signed-off-by: David S. Miller <davem@davemloft.net>

net: adding memory barrier to the poll and receive callbacks

Adding memory barrier after the poll_wait function, paired with
receive callbacks. Adding fuctions sock_poll_wait and sk_has_sleeper
to wrap the memory barrier.

Without the memory barrier, following race can happen.
The race fires, when following code paths meet, and the tp->rcv_nxt
and __add_wait_queue updates stay in CPU caches.

CPU1 CPU2

sys_select receive packet
... ...
__add_wait_queue update tp->rcv_nxt
... ...
tp->rcv_nxt check sock_def_readable
... {
schedule ...
if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
wake_up_interruptible(sk->sk_sleep)
...
}

If there was no cache the code would work ok, since the wait_queue and
rcv_nxt are opposit to each other.

Meaning that once tp->rcv_nxt is updated by CPU2, the CPU1 either already
passed the tp->rcv_nxt check and sleeps, or will get the new value for
tp->rcv_nxt and will return with new data mask.
In both cases the process (CPU1) is being added to the wait queue, so the
waitqueue_active (CPU2) call cannot miss and will wake up CPU1.

The bad case is when the __add_wait_queue changes done by CPU1 stay in its
cache, and so does the tp->rcv_nxt update on CPU2 side. The CPU1 will then
endup calling schedule and sleep forever if there are no more data on the
socket.

Calls to poll_wait in following modules were ommited:
net/bluetooth/af_bluetooth.c
net/irda/af_irda.c
net/irda/irnet/irnet_ppp.c
net/mac80211/rc80211_pid_debugfs.c
net/phonet/socket.c
net/rds/af_rds.c
net/rfkill/core.c
net/sunrpc/cache.c
net/sunrpc/rpc_pipe.c
net/tipc/socket.c

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

RxRPC: Fix a potential NULL dereference

Fix a potential NULL dereference bug during error handling in
rxrpc_kernel_begin_call(), whereby rxrpc_put_transport() may be handed a NULL
pointer.

This was found with a code checker (http://repo.or.cz/w/smatch.git/).

Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: replace NIPQUAD() in net/*/

Using NIPQUAD() with NIPQUAD_FMT, %d.%d.%d.%d or %u.%u.%u.%u
can be replaced with %pI4

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: convert BUG_TRAP to generic WARN_ON

Removes legacy reinvent-the-wheel type thing. The generic
machinery integrates much better to automated debugging aids
such as kerneloops.org (and others), and is unambiguous due to
better naming. Non-intuively BUG_TRAP() is actually equal to
WARN_ON() rather than BUG_ON() though some might actually be
promoted to BUG_ON() but I left that to future.

I could make at least one BUILD_BUG_ON conversion.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

AFS: Do not describe debug parameters with their value

Describe debug parameters with their names (and not their values).

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Convert ERR_PTR(PTR_ERR(p)) instances to ERR_CAST(p)

Convert instances of ERR_PTR(PTR_ERR(p)) to ERR_CAST(p) using:

perl -spi -e 's/ERR_PTR[(]PTR_ERR[(](.*)[)][)]/ERR_CAST(\1)/' `grep -rl 'ERR_PTR[(]*PTR_ERR' fs crypto net security`

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[NET]: Name magic constants in sock_wake_async()

The sock_wake_async() performs a bit different actions
depending on "how" argument. Unfortunately this argument
ony has numerical magic values.

I propose to give names to their constants to help people
reading this function callers understand what's going on
without looking into this function all the time.

I suppose this is 2.6.25 material, but if it's not (or the
naming seems poor/bad/awful), I can rework it against the
current net-2.6 tree.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET]: Forget the zero_it argument of sk_alloc()

Finally, the zero_it argument can be completely removed from
the callers and from the function prototype.

Besides, fix the checkpatch.pl warnings about using the
assignments inside if-s.

This patch is rather big, and it is a part of the previous one.
I splitted it wishing to make the patches more readable. Hope
this particular split helped.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

KEYS: Make request_key() and co fundamentally asynchronous

Make request_key() and co fundamentally asynchronous to make it easier for
NFS to make use of them. There are now accessor functions that do
asynchronous constructions, a wait function to wait for construction to
complete, and a completion function for the key type to indicate completion
of construction.

Note that the construction queue is now gone. Instead, keys under
construction are linked in to the appropriate keyring in advance, and that
anyone encountering one must wait for it to be complete before they can use
it. This is done automatically for userspace.

The following auxiliary changes are also made:

(1) Key type implementation stuff is split from linux/key.h into
linux/key-type.h.

(2) AF_RXRPC provides a way to allocate null rxrpc-type keys so that AFS does
not need to call key_instantiate_and_link() directly.

(3) Adjust the debugging macros so that they're -Wformat checked even if
they are disabled, and make it so they can be enabled simply by defining
__KDEBUG to be consistent with other code of mine.

(3) Documentation.

[alan@lxorguk.ukuu.org.uk: keys: missing word in documentation]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[NET]: Make socket creation namespace safe.

This patch passes in the namespace a new socket should be created in
and has the socket code do the appropriate reference counting. By
virtue of this all socket create methods are touched. In addition
the socket create methods are modified so that they will fail if
you attempt to create a socket in a non-default network namespace.

Failing if we attempt to create a socket outside of the default
network namespace ensures that as we incrementally make the network stack
network namespace aware we will not export functionality that someone
has not audited and made certain is network namespace safe.
Allowing us to partially enable network namespaces before all of the
exotic protocols are supported.

Any protocol layers I have missed will fail to compile because I now
pass an extra parameter into the socket creation code.

[ Integrated AF_IUCV build fixes from Andrew Morton... -DaveM ]

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET]: Make /proc/net per network namespace

This patch makes /proc/net per network namespace. It modifies the global
variables proc_net and proc_net_stat to be per network namespace.
The proc_net file helpers are modified to take a network namespace argument,
and all of their callers are fixed to pass &init_net for that argument.
This ensures that all of the /proc/net files are only visible and
usable in the initial network namespace until the code behind them
has been updated to be handle multiple network namespaces.

Making /proc/net per namespace is necessary as at least some files
in /proc/net depend upon the set of network devices which is per
network namespace, and even more files in /proc/net have contents
that are relevant to a single network namespace.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Cleanup non-arch xtime uses, use get_seconds() or current_kernel_time().

This avoids use of the kernel-internal "xtime" variable directly outside
of the actual time-related functions. Instead, use the helper functions
that we already have available to us.

This doesn't actually change any behaviour, but this will allow us to
fix the fact that "xtime" isn't updated very often with CONFIG_NO_HZ
(because much of the realtime information is maintained as separate
offsets to 'xtime'), which has caused interfaces that use xtime directly
to get a time that is out of sync with the real-time clock by up to a
third of a second or so.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: Remove slab destructors from kmem_cache_create().

Slab destructors were no longer supported after Christoph's
c59def9f222d44bb7e2f0a559f2906191a0862d7 change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

[NET] RXRPC: Fix whitespace errors.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

[AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use

Add an interface to the AF_RXRPC module so that the AFS filesystem module can
more easily make use of the services available. AFS still opens a socket but
then uses the action functions in lieu of sendmsg() and registers an intercept
functions to grab messages before they're queued on the socket Rx queue.

This permits AFS (or whatever) to:

(1) Avoid the overhead of using the recvmsg() call.

(2) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.

(3) Avoid calling request_key() at the point of issue of a call or opening of
a socket. This is done instead by AFS at the point of open(), unlink() or
other VFS operation and the key handed through.

(4) Request the use of something other than GFP_KERNEL to allocate memory.

Furthermore:

(*) The socket buffer markings used by RxRPC are made available for AFS so
that it can interpret the cooked RxRPC messages itself.

(*) rxgen (un)marshalling abort codes are made available.


The following documentation for the kernel interface is added to
Documentation/networking/rxrpc.txt:

=========================
AF_RXRPC KERNEL INTERFACE
=========================

The AF_RXRPC module also provides an interface for use by in-kernel utilities
such as the AFS filesystem. This permits such a utility to:

(1) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.

(2) Avoid having RxRPC call request_key() at the point of issue of a call or
opening of a socket. Instead the utility is responsible for requesting a
key at the appropriate point. AFS, for instance, would do this during VFS
operations such as open() or unlink(). The key is then handed through
when the call is initiated.

(3) Request the use of something other than GFP_KERNEL to allocate memory.

(4) Avoid the overhead of using the recvmsg() call. RxRPC messages can be
intercepted before they get put into the socket Rx queue and the socket
buffers manipulated directly.

To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
bind an addess as appropriate and listen if it's to be a server socket, but
then it passes this to the kernel interface functions.

The kernel interface functions are as follows:

(*) Begin a new client call.

struct rxrpc_call *
rxrpc_kernel_begin_call(struct socket *sock,
struct sockaddr_rxrpc *srx,
struct key *key,
unsigned long user_call_ID,
gfp_t gfp);

This allocates the infrastructure to make a new RxRPC call and assigns
call and connection numbers. The call will be made on the UDP port that
the socket is bound to. The call will go to the destination address of a
connected client socket unless an alternative is supplied (srx is
non-NULL).

If a key is supplied then this will be used to secure the call instead of
the key bound to the socket with the RXRPC_SECURITY_KEY sockopt. Calls
secured in this way will still share connections if at all possible.

The user_call_ID is equivalent to that supplied to sendmsg() in the
control data buffer. It is entirely feasible to use this to point to a
kernel data structure.

If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.

(*) End a client call.

void rxrpc_kernel_end_call(struct rxrpc_call *call);

This is used to end a previously begun call. The user_call_ID is expunged
from AF_RXRPC's knowledge and will not be seen again in association with
the specified call.

(*) Send data through a call.

int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
size_t len);

This is used to supply either the request part of a client call or the
reply part of a server call. msg.msg_iovlen and msg.msg_iov specify the
data buffers to be used. msg_iov may not be NULL and must point
exclusively to in-kernel virtual addresses. msg.msg_flags may be given
MSG_MORE if there will be subsequent data sends for this call.

The msg must not specify a destination address, control data or any flags
other than MSG_MORE. len is the total amount of data to transmit.

(*) Abort a call.

void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code);

This is used to abort a call if it's still in an abortable state. The
abort code specified will be placed in the ABORT message sent.

(*) Intercept received RxRPC messages.

typedef void (*rxrpc_interceptor_t)(struct sock *sk,
unsigned long user_call_ID,
struct sk_buff *skb);

void
rxrpc_kernel_intercept_rx_messages(struct socket *sock,
rxrpc_interceptor_t interceptor);

This installs an interceptor function on the specified AF_RXRPC socket.
All messages that would otherwise wind up in the socket's Rx queue are
then diverted to this function. Note that care must be taken to process
the messages in the right order to maintain DATA message sequentiality.

The interceptor function itself is provided with the address of the socket
and handling the incoming message, the ID assigned by the kernel utility
to the call and the socket buffer containing the message.

The skb->mark field indicates the type of message:

MARK MEANING
=============================== =======================================
RXRPC_SKB_MARK_DATA Data message
RXRPC_SKB_MARK_FINAL_ACK Final ACK received for an incoming call
RXRPC_SKB_MARK_BUSY Client call rejected as server busy
RXRPC_SKB_MARK_REMOTE_ABORT Call aborted by peer
RXRPC_SKB_MARK_NET_ERROR Network error detected
RXRPC_SKB_MARK_LOCAL_ERROR Local error encountered
RXRPC_SKB_MARK_NEW_CALL New incoming call awaiting acceptance

The remote abort message can be probed with rxrpc_kernel_get_abort_code().
The two error messages can be probed with rxrpc_kernel_get_error_number().
A new call can be accepted with rxrpc_kernel_accept_call().

Data messages can have their contents extracted with the usual bunch of
socket buffer manipulation functions. A data message can be determined to
be the last one in a sequence with rxrpc_kernel_is_data_last(). When a
data message has been used up, rxrpc_kernel_data_delivered() should be
called on it..

Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose
of. It is possible to get extra refs on all types of message for later
freeing, but this may pin the state of a call until the message is finally
freed.

(*) Accept an incoming call.

struct rxrpc_call *
rxrpc_kernel_accept_call(struct socket *sock,
unsigned long user_call_ID);

This is used to accept an incoming call and to assign it a call ID. This
function is similar to rxrpc_kernel_begin_call() and calls accepted must
be ended in the same way.

If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.

(*) Reject an incoming call.

int rxrpc_kernel_reject_call(struct socket *sock);

This is used to reject the first incoming call on the socket's queue with
a BUSY message. -ENODATA is returned if there were no incoming calls.
Other errors may be returned if the call had been aborted (-ECONNABORTED)
or had timed out (-ETIME).

(*) Record the delivery of a data message and free it.

void rxrpc_kernel_data_delivered(struct sk_buff *skb);

This is used to record a data message as having been delivered and to
update the ACK state for the call. The socket buffer will be freed.

(*) Free a message.

void rxrpc_kernel_free_skb(struct sk_buff *skb);

This is used to free a non-DATA socket buffer intercepted from an AF_RXRPC
socket.

(*) Determine if a data message is the last one on a call.

bool rxrpc_kernel_is_data_last(struct sk_buff *skb);

This is used to determine if a socket buffer holds the last data message
to be received for a call (true will be returned if it does, false
if not).

The data message will be part of the reply on a client call and the
request on an incoming call. In the latter case there will be more
messages, but in the former case there will not.

(*) Get the abort code from an abort message.

u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb);

This is used to extract the abort code from a remote abort message.

(*) Get the error number from a local or network error message.

int rxrpc_kernel_get_error_number(struct sk_buff *skb);

This is used to extract the error number from a message indicating either
a local error occurred or a network error occurred.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both

Provide AF_RXRPC sockets that can be used to talk to AFS servers, or serve
answers to AFS clients. KerberosIV security is fully supported. The patches
and some example test programs can be found in:

http://people.redhat.com/~dhowells/rxrpc/

This will eventually replace the old implementation of kernel-only RxRPC
currently resident in net/rxrpc/.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>