Commit Graph

100 Commits

Author SHA1 Message Date
David Howells
5e6ef4f101 rxrpc: Make the I/O thread take over the call and local processor work
Move the functions from the call->processor and local->processor work items
into the domain of the I/O thread.

The call event processor, now called from the I/O thread, then takes over
the job of cranking the call state machine, processing incoming packets and
transmitting DATA, ACK and ABORT packets.  In a future patch,
rxrpc_send_ACK() will transmit the ACK on the spot rather than queuing it
for later transmission.

The call event processor becomes purely received-skb driven.  It only
transmits things in response to events.  We use "pokes" to queue a dummy
skb to make it do things like start/resume transmitting data.  Timer expiry
also results in pokes.

The connection event processor, becomes similar, though crypto events, such
as dealing with CHALLENGE and RESPONSE packets is offloaded to a work item
to avoid doing crypto in the I/O thread.

The local event processor is removed and VERSION response packets are
generated directly from the packet parser.  Similarly, ABORTs generated in
response to protocol errors will be transmitted immediately rather than
being pushed onto a queue for later transmission.

Changes:
========
ver #2)
 - Fix a couple of introduced lock context imbalances.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:42 +00:00
David Howells
29fb4ec385 rxrpc: Remove RCU from peer->error_targets list
Remove the RCU requirements from the peer's list of error targets so that
the error distributor can call sleeping functions.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:41 +00:00
David Howells
cf37b59875 rxrpc: Move DATA transmission into call processor work item
Move DATA transmission into the call processor work item.  In a future
patch, this will be called from the I/O thread rather than being itsown
work item.

This will allow DATA transmission to be driven directly by incoming ACKs,
pokes and timers as those are processed.

The Tx queue is also split: The queue of packets prepared by sendmsg is now
places in call->tx_sendmsg and the packet dispatcher decants the packets
into call->tx_buffer as space becomes available in the transmission
window.  This allows sendmsg to run ahead of the available space to try and
prevent an underflow in transmission.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:41 +00:00
David Howells
f3441d4125 rxrpc: Copy client call parameters into rxrpc_call earlier
Copy client call parameters into rxrpc_call earlier so that that can be
used to convey them to the connection code - which can then be offloaded to
the I/O thread.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:41 +00:00
David Howells
9a36a6bc22 rxrpc: trace: Don't use __builtin_return_address for sk_buff tracing
In rxrpc tracing, use enums to generate lists of points of interest rather
than __builtin_return_address() for the sk_buff tracepoint.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:39 +00:00
David Howells
cb0fc0c972 rxrpc: trace: Don't use __builtin_return_address for rxrpc_call tracing
In rxrpc tracing, use enums to generate lists of points of interest rather
than __builtin_return_address() for the rxrpc_call tracepoint

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:39 +00:00
David Howells
0fde882fc9 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
2022-12-01 13:36:38 +00:00
David Howells
2cc800863c rxrpc: Drop rxrpc_conn_parameters from rxrpc_connection and rxrpc_bundle
Remove the rxrpc_conn_parameters struct from the rxrpc_connection and
rxrpc_bundle structs and emplace the members directly.  These are going to
get filled in from the rxrpc_call struct in future.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:38 +00:00
David Howells
2ebdb26e6a rxrpc: Remove the [k_]proto() debugging macros
Remove the kproto() and _proto() debugging macros in preference to using
tracepoints for this.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:38 +00:00
David S. Miller
8cf4f8c7d9 rxrpc fixes for net-next
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Merge tag 'rxrpc-next-20221116' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

David Howells says:

====================
rxrpc: Fix oops and missing config conditionals

The patches that were pulled into net-next previously[1] had some issues
that this patchset fixes:

 (1) Fix missing IPV6 config conditionals.

 (2) Fix an oops caused by calling udpv6_sendmsg() directly on an AF_INET
     socket.

 (3) Fix the validation of network addresses on entry to socket functions
     so that we don't allow an AF_INET6 address if we've selected an
     AF_INET transport socket.

Link: https://lore.kernel.org/r/166794587113.2389296.16484814996876530222.stgit@warthog.procyon.org.uk/ [1]
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2022-11-18 12:09:20 +00:00
Dan Carpenter
3846189483 rxrpc: uninitialized variable in rxrpc_send_ack_packet()
The "pkt" was supposed to have been deleted in a previous patch.  It
leads to an uninitialized variable bug.

Fixes: 72f0c6fb05 ("rxrpc: Allocate ACK records at proposal and queue for transmission")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-11-18 12:03:01 +00:00
David Howells
6423ac2eb3 rxrpc: Fix oops from calling udpv6_sendmsg() on AF_INET socket
If rxrpc sees an IPv6 address, it assumes it can call udpv6_sendmsg() on it
- even if it got it on an IPv4 socket.  Fix do_udp_sendmsg() to give an
error in such a case.

general protection fault, probably for non-canonical address
0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
...
RIP: 0010:ipv6_addr_v4mapped include/net/ipv6.h:749 [inline]
RIP: 0010:udpv6_sendmsg+0xd0a/0x2c70 net/ipv6/udp.c:1361
...
Call Trace:
do_udp_sendmsg net/rxrpc/output.c:27 [inline]
do_udp_sendmsg net/rxrpc/output.c:21 [inline]
rxrpc_send_abort_packet+0x73b/0x860 net/rxrpc/output.c:367
rxrpc_release_calls_on_socket+0x211/0x300 net/rxrpc/call_object.c:595
rxrpc_release_sock net/rxrpc/af_rxrpc.c:886 [inline]
rxrpc_release+0x263/0x5a0 net/rxrpc/af_rxrpc.c:917
__sock_release+0xcd/0x280 net/socket.c:650
sock_close+0x18/0x20 net/socket.c:1365
__fput+0x27c/0xa90 fs/file_table.c:320
task_work_run+0x16b/0x270 kernel/task_work.c:179
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xb35/0x2a20 kernel/exit.c:820
do_group_exit+0xd0/0x2a0 kernel/exit.c:950
__do_sys_exit_group kernel/exit.c:961 [inline]
__se_sys_exit_group kernel/exit.c:959 [inline]
__x64_sys_exit_group+0x3a/0x50 kernel/exit.c:959

Fixes: ed472b0c87 ("rxrpc: Call udp_sendmsg() directly")
Reported-by: Eric Dumazet <edumazet@google.com>
Suggested-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
2022-11-16 08:05:11 +00:00
David Howells
1fc4fa2ac9 rxrpc: Fix congestion management
rxrpc has a problem in its congestion management in that it saves the
congestion window size (cwnd) from one call to another, but if this is 0 at
the time is saved, then the next call may not actually manage to ever
transmit anything.

To this end:

 (1) Don't save cwnd between calls, but rather reset back down to the
     initial cwnd and re-enter slow-start if data transmission is idle for
     more than an RTT.

 (2) Preserve ssthresh instead, as that is a handy estimate of pipe
     capacity.  Knowing roughly when to stop slow start and enter
     congestion avoidance can reduce the tendency to overshoot and drop
     larger amounts of packets when probing.

In future, cwind growth also needs to be constrained when the window isn't
being filled due to being application limited.

Reported-by: Simon Wilkinson <sxw@auristor.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells
4e76bd406d rxrpc: Remove call->lock
call->lock is no longer necessary, so remove it.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells
a4ea4c4776 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
2022-11-08 16:42:28 +00:00
David Howells
5d7edbc923 rxrpc: Get rid of the Rx ring
Get rid of the Rx ring and replace it with a pair of queues instead.  One
queue gets the packets that are in-sequence and are ready for processing by
recvmsg(); the other queue gets the out-of-sequence packets for addition to
the first queue as the holes get filled.

The annotation ring is removed and replaced with a SACK table.  The SACK
table has the bits set that correspond exactly to the sequence number of
the packet being acked.  The SACK ring is copied when an ACK packet is
being assembled and rotated so that the first ACK is in byte 0.

Flow control handling is altered so that packets that are moved to the
in-sequence queue are hard-ACK'd even before they're consumed - and then
the Rx window size in the ACK packet (rsize) is shrunk down to compensate
(even going to 0 if the window is full).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells
d4d02d8bb5 rxrpc: Clone received jumbo subpackets and queue separately
Split up received jumbo packets into separate skbuffs by cloning the
original skbuff for each subpacket and setting the offset and length of the
data in that subpacket in the skbuff's private data.  The subpackets are
then placed on the recvmsg queue separately.  The security class then gets
to revise the offset and length to remove its metadata.

If we fail to clone a packet, we just drop it and let the peer resend it.
The original packet gets used for the final subpacket.

This should make it easier to handle parallel decryption of the subpackets.
It also simplifies the handling of lost or misordered packets in the
queuing/buffering loop as the possibility of overlapping jumbo packets no
longer needs to be considered.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells
530403d9ba rxrpc: Clean up ACK handling
Clean up the rxrpc_propose_ACK() function.  If deferred PING ACK proposal
is split out, it's only really needed for deferred DELAY ACKs.  All other
ACKs, bar terminal IDLE ACK are sent immediately.  The deferred IDLE ACK
submission can be handled by conversion of a DELAY ACK into an IDLE ACK if
there's nothing to be SACK'd.

Also, because there's a delay between an ACK being generated and being
transmitted, it's possible that other ACKs of the same type will be
generated during that interval.  Apart from the ACK time and the serial
number responded to, most of the ACK body, including window and SACK
parameters, are not filled out till the point of transmission - so we can
avoid generating a new ACK if there's one pending that will cover the SACK
data we need to convey.

Therefore, don't propose a new DELAY or IDLE ACK for a call if there's one
already pending.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells
72f0c6fb05 rxrpc: Allocate ACK records at proposal and queue for transmission
Allocate rxrpc_txbuf records for ACKs and put onto a queue for the
transmitter thread to dispatch.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells
ed472b0c87 rxrpc: Call udp_sendmsg() directly
Call udp_sendmsg() and udpv6_sendmsg() directly rather than calling
kernel_sendmsg() as the latter assumes we want a kvec-class iterator.
However, zerocopy explicitly doesn't work with such an iterator.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells
8889a711f9 rxrpc: Fix ack.bufferSize to be 0 when generating an ack
ack.bufferSize should be set to 0 when generating an ack.

Fixes: 8d94aa381d ("rxrpc: Calls shouldn't hold socket refs")
Reported-by: Jeffrey Altman <jaltman@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:15 +00:00
David Howells
f7fa52421f rxrpc: Record stats for why the REQUEST-ACK flag is being set
Record stats for why the REQUEST-ACK flag is being set.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:15 +00:00
David Howells
f2a676d100 rxrpc: Record statistics about ACK types
Record statistics about the different types of ACKs that have been
transmitted and received and the number of ACKs that have been filled out
and transmitted or that have been skipped.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:15 +00:00
David Howells
b015424695 rxrpc: Add stats procfile and DATA packet stats
Add a procfile, /proc/net/rxrpc/stats, to display some statistics about
what rxrpc has been doing.  Writing a blank line to the stats file will
clear the increment-only counters.  Allocated resource counters don't get
cleared.

Add some counters to count various things about DATA packets, including the
number created, transmitted and retransmitted and the number received, the
number of ACK-requests markings and the number of jumbo packets received.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:15 +00:00
David Howells
4d843be56b rxrpc: Trace setting of the request-ack flag
Add a tracepoint to log why the request-ack flag is set on an outgoing DATA
packet, allowing debugging as to why.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:15 +00:00
David Howells
9a3dedcf18 rxrpc: Fix decision on when to generate an IDLE ACK
Fix the decision on when to generate an IDLE ACK by keeping a count of the
number of packets we've received, but not yet soft-ACK'd, and the number of
packets we've processed, but not yet hard-ACK'd, rather than trying to keep
track of which DATA sequence numbers correspond to those points.

We then generate an ACK when either counter exceeds 2.  The counters are
both cleared when we transcribe the information into any sort of ACK packet
for transmission.  IDLE and DELAY ACKs are skipped if both counters are 0
(ie. no change).

Fixes: 805b21b929 ("rxrpc: Send an ACK after every few DATA packets we receive")
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>
2022-05-22 21:30:53 +01:00
David Howells
81524b6312 rxrpc: Don't let ack.previousPacket regress
The previousPacket field in the rx ACK packet should never go backwards -
it's now the highest DATA sequence number received, not the last on
received (it used to be used for out of sequence detection).

Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
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>
2022-05-22 21:30:53 +01:00
David Howells
2c13c05c5f rxrpc: Adjust retransmission backoff
Improve retransmission backoff by only backing off when we retransmit data
packets rather than when we set the lost ack timer.

To this end:

 (1) In rxrpc_resend(), use rxrpc_get_rto_backoff() when setting the
     retransmission timer and only tell it that we are retransmitting if we
     actually have things to retransmit.

     Note that it's possible for the retransmission algorithm to race with
     the processing of a received ACK, so we may see no packets needing
     retransmission.

 (2) In rxrpc_send_data_packet(), don't bump the backoff when setting the
     ack_lost_at timer, as it may then get bumped twice.

With this, when looking at one particular packet, the retransmission
intervals were seen to be 1.5ms, 2ms, 3ms, 5ms, 9ms, 17ms, 33ms, 71ms,
136ms, 264ms, 544ms, 1.088s, 2.1s, 4.2s and 8.3s.

Fixes: c410bf0193 ("rxrpc: Fix the excessive initial retransmission timeout")
Suggested-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/164138117069.2023386.17446904856843997127.stgit@warthog.procyon.org.uk/
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-22 02:03:24 +00:00
David Howells
245500d853 rxrpc: Rewrite the client connection manager
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 <dhowells@redhat.com>
2020-09-08 21:11:43 +01:00
David Howells
4700c4d80b rxrpc: Fix loss of RTT samples due to interposed ACK
The Rx protocol has a mechanism to help generate RTT samples that works by
a client transmitting a REQUESTED-type ACK when it receives a DATA packet
that has the REQUEST_ACK flag set.

The peer, however, may interpose other ACKs before transmitting the
REQUESTED-ACK, as can be seen in the following trace excerpt:

 rxrpc_tx_data: c=00000044 DATA d0b5ece8:00000001 00000001 q=00000001 fl=07
 rxrpc_rx_ack: c=00000044 00000001 PNG r=00000000 f=00000002 p=00000000 n=0
 rxrpc_rx_ack: c=00000044 00000002 REQ r=00000001 f=00000002 p=00000001 n=0
 ...

DATA packet 1 (q=xx) has REQUEST_ACK set (bit 1 of fl=xx).  The incoming
ping (labelled PNG) hard-acks the request DATA packet (f=xx exceeds the
sequence number of the DATA packet), causing it to be discarded from the Tx
ring.  The ACK that was requested (labelled REQ, r=xx references the serial
of the DATA packet) comes after the ping, but the sk_buff holding the
timestamp has gone and the RTT sample is lost.

This is particularly noticeable on RPC calls used to probe the service
offered by the peer.  A lot of peers end up with an unknown RTT because we
only ever sent a single RPC.  This confuses the server rotation algorithm.

Fix this by caching the information about the outgoing packet in RTT
calculations in the rxrpc_call struct rather than looking in the Tx ring.

A four-deep buffer is maintained and both REQUEST_ACK-flagged DATA and
PING-ACK transmissions are recorded in there.  When the appropriate
response ACK is received, the buffer is checked for a match and, if found,
an RTT sample is recorded.

If a received ACK refers to a packet with a later serial number than an
entry in the cache, that entry is presumed lost and the entry is made
available to record a new transmission.

ACKs types other than REQUESTED-type and PING-type cause any matching
sample to be cancelled as they don't necessarily represent a useful
measurement.

If there's no space in the buffer on ping/data transmission, the sample
base is discarded.

Fixes: 50235c4b5a ("rxrpc: Obtain RTT data by requesting ACKs on DATA packets")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-08-20 17:59:27 +01:00
Christoph Hellwig
2de569bda2 ipv4: add ip_sock_set_mtu_discover
Add a helper to directly set the IP_MTU_DISCOVER sockopt from kernel
space without going through a fake uaccess.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com> [rxrpc bits]
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-28 11:11:45 -07:00
David Howells
c410bf0193 rxrpc: Fix the excessive initial retransmission timeout
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: 17926a7932 ([AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both"")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-05-11 16:42:28 +01:00
David Howells
0e631eee17 rxrpc: Fix DATA Tx to disable nofrag for UDP on AF_INET6 socket
Fix the DATA packet transmission to disable nofrag for UDPv4 on an AF_INET6
socket as well as UDPv6 when trying to transmit fragmentably.

Without this, packets filled to the normal size used by the kernel AFS
client of 1412 bytes be rejected by udp_sendmsg() with EMSGSIZE
immediately.  The ->sk_error_report() notification hook is called, but
rxrpc doesn't generate a trace for it.

This is a temporary fix; a more permanent solution needs to involve
changing the size of the packets being filled in accordance with the MTU,
which isn't currently done in AF_RXRPC.  The reason for not doing so was
that, barring the last packet in an rx jumbo packet, jumbos can only be
assembled out of 1412-byte packets - and the plan was to construct jumbos
on the fly at transmission time.

Also, there's no point turning on IPV6_MTU_DISCOVER, since IPv6 has to
engage in this anyway since fragmentation is only done by the sender.  We
can then condense the switch-statement in rxrpc_send_data_packet().

Fixes: 75b54cb57c ("rxrpc: Add IPv6 support")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-14 16:26:47 -07:00
David Howells
5273a191dc rxrpc: Fix NULL pointer deref due to call->conn being cleared on disconnect
When a call is disconnected, the connection pointer from the call is
cleared to make sure it isn't used again and to prevent further attempted
transmission for the call.  Unfortunately, there might be a daemon trying
to use it at the same time to transmit a packet.

Fix this by keeping call->conn set, but setting a flag on the call to
indicate disconnection instead.

Remove also the bits in the transmission functions where the conn pointer is
checked and a ref taken under spinlock as this is now redundant.

Fixes: 8d94aa381d ("rxrpc: Calls shouldn't hold socket refs")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-02-03 10:25:30 +00:00
David Howells
987db9f7cd rxrpc: Use the tx-phase skb flag to simplify tracing
Use the previously-added transmit-phase skbuff private flag to simplify the
socket buffer tracing a bit.  Which phase the skbuff comes from can now be
divined from the skb rather than having to be guessed from the call state.

We can also reduce the number of rxrpc_skb_trace values by eliminating the
difference between Tx and Rx in the symbols.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-08-27 10:04:18 +01:00
David Howells
e8c3af6bb3 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>
2019-08-09 15:24:00 +01:00
David Howells
3427beb637 rxrpc: Fix uninitialized error code in rxrpc_send_data_packet()
With gcc 4.1:

    net/rxrpc/output.c: In function ‘rxrpc_send_data_packet’:
    net/rxrpc/output.c:338: warning: ‘ret’ may be used uninitialized in this function

Indeed, if the first jump to the send_fragmentable label is made, and
the address family is not handled in the switch() statement, ret will be
used uninitialized.

Fix this by BUG()'ing as is done in other places in rxrpc where internal
support for future address families will need adding.  It should not be
possible to reach this normally as the address families are checked
up-front.

Fixes: 5a924b8951 ("rxrpc: Don't store the rxrpc header in the Tx queue sk_buffs")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-07-02 12:09:09 -07:00
Thomas Gleixner
2874c5fd28 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>
2019-05-30 11:26:32 -07:00
Arnd Bergmann
526949e877 rxrpc: avoid clang -Wuninitialized warning
clang produces a false-positive warning as it fails to notice
that "lost = true" implies that "ret" is initialized:

net/rxrpc/output.c:402:6: error: variable 'ret' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
        if (lost)
            ^~~~
net/rxrpc/output.c:437:6: note: uninitialized use occurs here
        if (ret >= 0) {
            ^~~
net/rxrpc/output.c:402:2: note: remove the 'if' if its condition is always false
        if (lost)
        ^~~~~~~~~
net/rxrpc/output.c:339:9: note: initialize the variable 'ret' to silence this warning
        int ret, opt;
               ^
                = 0

Rearrange the code to make that more obvious and avoid the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-23 21:48:30 -04:00
David Howells
c7e86acfce rxrpc: Fix lockup due to no error backoff after ack transmit error
If the network becomes (partially) unavailable, say by disabling IPv6, the
background ACK transmission routine can get itself into a tizzy by
proposing immediate ACK retransmission.  Since we're in the call event
processor, that happens immediately without returning to the workqueue
manager.

The condition should clear after a while when either the network comes back
or the call times out.

Fix this by:

 (1) When re-proposing an ACK on failed Tx, don't schedule it immediately.
     This will allow a certain amount of time to elapse before we try
     again.

 (2) Enforce a return to the workqueue manager after a certain number of
     iterations of the call processing loop.

 (3) Add a backoff delay that increases the delay on deferred ACKs by a
     jiffy per failed transmission to a limit of HZ.  The backoff delay is
     cleared on a successful return from kernel_sendmsg().

 (4) Cancel calls immediately if the opening sendmsg fails.  The layer
     above can arrange retransmission or rotate to another server.

Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-02 23:59:26 -07:00
David S. Miller
2e2d6f0342 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
net/sched/cls_api.c has overlapping changes to a call to
nlmsg_parse(), one (from 'net') added rtm_tca_policy instead of NULL
to the 5th argument, and another (from 'net-next') added cb->extack
instead of NULL to the 6th argument.

net/ipv4/ipmr_base.c is a case of a bug fix in 'net' being done to
code which moved (to mr_table_dump)) in 'net-next'.  Thanks to David
Ahern for the heads up.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-19 11:03:06 -07:00
YueHaibing
d6672a5a97 rxrpc: use correct kvec num when sending BUSY response packet
Fixes gcc '-Wunused-but-set-variable' warning:

net/rxrpc/output.c: In function 'rxrpc_reject_packets':
net/rxrpc/output.c:527:11: warning:
 variable 'ioc' set but not used [-Wunused-but-set-variable]

'ioc' is the correct kvec num when sending a BUSY (or an ABORT) response
packet.

Fixes: ece64fec16 ("rxrpc: Emit BUSY packets when supposed to rather than ABORTs")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-15 22:08:17 -07:00
David Howells
5a790b7375 rxrpc: Drop the local endpoint arg from rxrpc_extract_addr_from_skb()
rxrpc_extract_addr_from_skb() doesn't use the argument that points to the
local endpoint, so remove the argument.

Signed-off-by: David Howells <dhowells@redhat.com>
2018-10-04 09:32:28 +01:00
David Howells
b3cfb6f567 rxrpc: Emit the data Tx trace line before transmitting
Print the data Tx trace line before transmitting so that it appears before
the trace lines indicating success or failure of the transmission.  This
makes the trace log less confusing.

Signed-off-by: David Howells <dhowells@redhat.com>
2018-10-04 09:32:27 +01:00
David Howells
ece64fec16 rxrpc: Emit BUSY packets when supposed to rather than ABORTs
In the input path, a received sk_buff can be marked for rejection by
setting RXRPC_SKB_MARK_* in skb->mark and, if needed, some auxiliary data
(such as an abort code) in skb->priority.  The rejection is handled by
queueing the sk_buff up for dealing with in process context.  The output
code reads the mark and priority and, theoretically, generates an
appropriate response packet.

However, if RXRPC_SKB_MARK_BUSY is set, this isn't noticed and an ABORT
message with a random abort code is generated (since skb->priority wasn't
set to anything).

Fix this by outputting the appropriate sort of packet.

Also, whilst we're at it, most of the marks are no longer used, so remove
them and rename the remaining two to something more obvious.

Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
2018-09-28 10:32:19 +01:00
David Howells
b604dd9883 rxrpc: Fix RTT gathering
Fix RTT information gathering in AF_RXRPC by the following means:

 (1) Enable Rx timestamping on the transport socket with SO_TIMESTAMPNS.

 (2) If the sk_buff doesn't have a timestamp set when rxrpc_data_ready()
     collects it, set it at that point.

 (3) Allow ACKs to be requested on the last packet of a client call, but
     not a service call.  We need to be careful lest we undo:

	bf7d620abf
	Author: David Howells <dhowells@redhat.com>
	Date:   Thu Oct 6 08:11:51 2016 +0100
	rxrpc: Don't request an ACK on the last DATA packet of a call's Tx phase

     but that only really applies to service calls that we're handling,
     since the client side gets to send the final ACK (or not).

 (4) When about to transmit an ACK or DATA packet, record the Tx timestamp
     before only; don't update the timestamp afterwards.

 (5) Switch the ordering between recording the serial and recording the
     timestamp to always set the serial number first.  The serial number
     shouldn't be seen referenced by an ACK packet until we've transmitted
     the packet bearing it - so in the Rx path, we don't need the timestamp
     until we've checked the serial number.

Fixes: cf1a6474f8 ("rxrpc: Add per-peer RTT tracker")
Signed-off-by: David Howells <dhowells@redhat.com>
2018-09-28 10:32:03 +01:00
David S. Miller
a736e07468 Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net
Overlapping changes in RXRPC, changing to ktime_get_seconds() whilst
adding some tracepoints.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-09 11:52:36 -07:00
David Howells
330bdcfadc rxrpc: Fix the keepalive generator [ver #2]
AF_RXRPC has a keepalive message generator that generates a message for a
peer ~20s after the last transmission to that peer to keep firewall ports
open.  The implementation is incorrect in the following ways:

 (1) It mixes up ktime_t and time64_t types.

 (2) It uses ktime_get_real(), the output of which may jump forward or
     backward due to adjustments to the time of day.

 (3) If the current time jumps forward too much or jumps backwards, the
     generator function will crank the base of the time ring round one slot
     at a time (ie. a 1s period) until it catches up, spewing out VERSION
     packets as it goes.

Fix the problem by:

 (1) Only using time64_t.  There's no need for sub-second resolution.

 (2) Use ktime_get_seconds() rather than ktime_get_real() so that time
     isn't perceived to go backwards.

 (3) Simplifying rxrpc_peer_keepalive_worker() by splitting it into two
     parts:

     (a) The "worker" function that manages the buckets and the timer.

     (b) The "dispatch" function that takes the pending peers and
     	 potentially transmits a keepalive packet before putting them back
     	 in the ring into the slot appropriate to the revised last-Tx time.

 (4) Taking everything that's pending out of the ring and splicing it into
     a temporary collector list for processing.

     In the case that there's been a significant jump forward, the ring
     gets entirely emptied and then the time base can be warped forward
     before the peers are processed.

     The warping can't happen if the ring isn't empty because the slot a
     peer is in is keepalive-time dependent, relative to the base time.

 (5) Limit the number of iterations of the bucket array when scanning it.

 (6) Set the timer to skip any empty slots as there's no point waking up if
     there's nothing to do yet.

This can be triggered by an incoming call from a server after a reboot with
AF_RXRPC and AFS built into the kernel causing a peer record to be set up
before userspace is started.  The system clock is then adjusted by
userspace, thereby potentially causing the keepalive generator to have a
meltdown - which leads to a message like:

	watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [kworker/0:1:23]
	...
	Workqueue: krxrpcd rxrpc_peer_keepalive_worker
	EIP: lock_acquire+0x69/0x80
	...
	Call Trace:
	 ? rxrpc_peer_keepalive_worker+0x5e/0x350
	 ? _raw_spin_lock_bh+0x29/0x60
	 ? rxrpc_peer_keepalive_worker+0x5e/0x350
	 ? rxrpc_peer_keepalive_worker+0x5e/0x350
	 ? __lock_acquire+0x3d3/0x870
	 ? process_one_work+0x110/0x340
	 ? process_one_work+0x166/0x340
	 ? process_one_work+0x110/0x340
	 ? worker_thread+0x39/0x3c0
	 ? kthread+0xdb/0x110
	 ? cancel_delayed_work+0x90/0x90
	 ? kthread_stop+0x70/0x70
	 ? ret_from_fork+0x19/0x24

Fixes: ace45bec6d ("rxrpc: Fix firewall route keepalive")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-08 19:10:26 -07:00
David Howells
4764c0da69 rxrpc: Trace packet transmission
Trace successful packet transmission (kernel_sendmsg() succeeded, that is)
in AF_RXRPC.  We can share the enum that defines the transmission points
with the trace_rxrpc_tx_fail() tracepoint, so rename its constants to be
applicable to both.

Also, save the internal call->debug_id in the rxrpc_channel struct so that
it can be used in retransmission trace lines.

Signed-off-by: David Howells <dhowells@redhat.com>
2018-08-01 13:28:23 +01:00
David Howells
6b47fe1d1c rxrpc: Trace UDP transmission failure
Add a tracepoint to log transmission failure from the UDP transport socket
being used by AF_RXRPC.

Signed-off-by: David Howells <dhowells@redhat.com>
2018-05-10 23:26:01 +01:00