linux.git/net/rxrpc/proc.c, branch v5.12

rxrpc: Rewrite the client connection manager

2020-09-08T20:11:43+00:00

Rewrite the rxrpc client connection manager so that it can support multiple
connections for a given security key to a peer.  The following changes are
made:

 (1) For each open socket, the code currently maintains an rbtree with the
     connections placed into it, keyed by communications parameters.  This
     is tricky to maintain as connections can be culled from the tree or
     replaced within it.  Connections can require replacement for a number
     of reasons, e.g. their IDs span too great a range for the IDR data
     type to represent efficiently, the call ID numbers on that conn would
     overflow or the conn got aborted.

     This is changed so that there's now a connection bundle object placed
     in the tree, keyed on the same parameters.  The bundle, however, does
     not need to be replaced.

 (2) An rxrpc_bundle object can now manage the available channels for a set
     of parallel connections.  The lock that manages this is moved there
     from the rxrpc_connection struct (channel_lock).

 (3) There'a a dummy bundle for all incoming connections to share so that
     they have a channel_lock too.  It might be better to give each
     incoming connection its own bundle.  This bundle is not needed to
     manage which channels incoming calls are made on because that's the
     solely at whim of the client.

 (4) The restrictions on how many client connections are around are
     removed.  Instead, a previous patch limits the number of client calls
     that can be allocated.  Ordinarily, client connections are reaped
     after 2 minutes on the idle queue, but when more than a certain number
     of connections are in existence, the reaper starts reaping them after
     2s of idleness instead to get the numbers back down.

     It could also be made such that new call allocations are forced to
     wait until the number of outstanding connections subsides.

Signed-off-by: David Howells

rxrpc: Adjust /proc/net/rxrpc/calls to display call->debug_id not user_ID

2020-05-31T14:19:51+00:00

The user ID value isn't actually much use - and leaks a kernel pointer or a
userspace value - so replace it with the call debug ID, which appears in trace
points.

Signed-off-by: David Howells

rxrpc: Fix the excessive initial retransmission timeout

2020-05-11T15:42:28+00:00

rxrpc currently uses a fixed 4s retransmission timeout until the RTT is
sufficiently sampled. This can cause problems with some fileservers with
calls to the cache manager in the afs filesystem being dropped from the
fileserver because a packet goes missing and the retransmission timeout is
greater than the call expiry timeout.

Fix this by:

(1) Copying the RTT/RTO calculation code from Linux's TCP implementation
and altering it to fit rxrpc.

(2) Altering the various users of the RTT to make use of the new SRTT
value.

(3) Replacing the use of rxrpc_resend_timeout to use the calculated RTO
value instead (which is needed in jiffies), along with a backoff.

Notes:

(1) rxrpc provides RTT samples by matching the serial numbers on outgoing
DATA packets that have the RXRPC_REQUEST_ACK set and PING ACK packets
against the reference serial number in incoming REQUESTED ACK and
PING-RESPONSE ACK packets.

(2) Each packet that is transmitted on an rxrpc connection gets a new
per-connection serial number, even for retransmissions, so an ACK can
be cross-referenced to a specific trigger packet. This allows RTT
information to be drawn from retransmitted DATA packets also.

(3) rxrpc maintains the RTT/RTO state on the rxrpc_peer record rather than
on an rxrpc_call because many RPC calls won't live long enough to
generate more than one sample.

(4) The calculated SRTT value is in units of 8ths of a microsecond rather
than nanoseconds.

The (S)RTT and RTO values are displayed in /proc/net/rxrpc/peers.

Fixes: 17926a79320a ([AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both"")
Signed-off-by: David Howells

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

2019-05-30T18:26:32+00:00

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 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman

rxrpc: Add /proc/net/rxrpc/peers to display peer list

2018-10-16T05:52:58+00:00

Add /proc/net/rxrpc/peers to display the list of peers currently active.

Signed-off-by: David Howells 
Signed-off-by: David S. Miller

rxrpc: Remove set but not used variable 'nowj'

2018-08-02T17:18:20+00:00

Fixes gcc '-Wunused-but-set-variable' warning:

net/rxrpc/proc.c: In function 'rxrpc_call_seq_show':
net/rxrpc/proc.c:66:29: warning:
 variable 'nowj' set but not used [-Wunused-but-set-variable]
  unsigned long timeout = 0, nowj;
                             ^

Signed-off-by: Wei Yongjun 
Signed-off-by: David Howells 
Signed-off-by: David S. Miller

rxrpc: Show some more information through /proc files

2018-08-01T12:28:23+00:00

Show the four current call IDs in /proc/net/rxrpc/conns.

Show the current packet Rx serial number in /proc/net/rxrpc/calls.

Signed-off-by: David Howells

rxrpc: Display call expect-receive-by timeout in proc

2018-08-01T12:28:23+00:00

Display in /proc/net/rxrpc/calls the timeout by which a call next expects
to receive a packet.

This makes it easier to debug timeout issues.

Signed-off-by: David Howells

proc: introduce proc_create_net{,_data}

2018-05-16T05:24:30+00:00

Variants of proc_create{,_data} that directly take a struct seq_operations
and deal with network namespaces in ->open and ->release.  All callers of
proc_create + seq_open_net converted over, and seq_{open,release}_net are
removed entirely.

Signed-off-by: Christoph Hellwig

rxrpc: Fix checker warnings and errors

2018-03-30T20:05:17+00:00

Fix various issues detected by checker.

Errors:

 (*) rxrpc_discard_prealloc() should be using rcu_assign_pointer to set
     call->socket.

Warnings:

 (*) rxrpc_service_connection_reaper() should be passing NULL rather than 0 to
     trace_rxrpc_conn() as the where argument.

 (*) rxrpc_disconnect_client_call() should get its net pointer via the
     call->conn rather than call->sock to avoid a warning about accessing
     an RCU pointer without protection.

 (*) Proc seq start/stop functions need annotation as they pass locks
     between the functions.

False positives:

 (*) Checker doesn't correctly handle of seq-retry lock context balance in
     rxrpc_find_service_conn_rcu().

 (*) Checker thinks execution may proceed past the BUG() in
     rxrpc_publish_service_conn().

 (*) Variable length array warnings from SKCIPHER_REQUEST_ON_STACK() in
     rxkad.c.

Signed-off-by: David Howells