As udp_port_cfg struct changes its members with dependency on IPv6
configuration, the code in rxrpc should also check for IPv6.
Fixes: 1a9b86c9fd ("rxrpc: use udp tunnel APIs instead of open code in rxrpc_open_socket")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The changes to make rxrpc create the udp socket missed a bit to add the
Kconfig dependency on the udp tunnel code to do this.
Fix this by adding making AF_RXRPC select NET_UDP_TUNNEL.
Fixes: 1a9b86c9fd ("rxrpc: use udp tunnel APIs instead of open code in rxrpc_open_socket")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
cc: alaa@dev.mellanox.co.il
cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
In rxrpc_open_socket(), now it's using sock_create_kern() and
kernel_bind() to create a udp tunnel socket, and other kernel
APIs to set up it. These code can be replaced with udp tunnel
APIs udp_sock_create() and setup_udp_tunnel_sock(), and it'll
simplify rxrpc_open_socket().
Note that with this patch, the udp tunnel socket will always
bind to a random port if transport is not provided by users,
which is suggested by David Howells, thanks!
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Vadim Fedorenko <vfedorenko@novek.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
When doing encap_enable/increasing encap_needed_key, up->encap_enabled
is not set in rxrpc_open_socket(), and it will cause encap_needed_key
not being decreased in udpv6_destroy_sock().
This patch is to improve it by just calling udp_tunnel_encap_enable()
where it increases both UDP and UDPv6 encap_needed_key and sets
up->encap_enabled.
v4->v5:
- add the missing '#include <net/udp_tunnel.h>', as David Howells
noticed.
Acked-and-tested-by: David Howells <dhowells@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
At the end of rxrpc_release_call(), rxrpc_cleanup_ring() is called to clear
the Rx/Tx skbuff ring, but this doesn't lock the ring whilst it's accessing
it. Unfortunately, rxrpc_resend() might be trying to retransmit a packet
concurrently with this - and whilst it does lock the ring, this isn't
protection against rxrpc_cleanup_call().
Fix this by removing the call to rxrpc_cleanup_ring() from
rxrpc_release_call(). rxrpc_cleanup_ring() will be called again anyway
from rxrpc_cleanup_call(). The earlier call is just an optimisation to
recycle skbuffs more quickly.
Alternative solutions include rxrpc_release_call() could try to cancel the
work item or wait for it to complete or rxrpc_cleanup_ring() could lock
when accessing the ring (which would require a bh lock).
This can produce a report like the following:
BUG: KASAN: use-after-free in rxrpc_send_data_packet+0x19b4/0x1e70 net/rxrpc/output.c:372
Read of size 4 at addr ffff888011606e04 by task kworker/0:0/5
...
Workqueue: krxrpcd rxrpc_process_call
Call Trace:
...
kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413
rxrpc_send_data_packet+0x19b4/0x1e70 net/rxrpc/output.c:372
rxrpc_resend net/rxrpc/call_event.c:266 [inline]
rxrpc_process_call+0x1634/0x1f60 net/rxrpc/call_event.c:412
process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
...
Allocated by task 2318:
...
sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2348
rxrpc_send_data+0xb51/0x2bf0 net/rxrpc/sendmsg.c:358
rxrpc_do_sendmsg+0xc03/0x1350 net/rxrpc/sendmsg.c:744
rxrpc_sendmsg+0x420/0x630 net/rxrpc/af_rxrpc.c:560
...
Freed by task 2318:
...
kfree_skb+0x140/0x3f0 net/core/skbuff.c:704
rxrpc_free_skb+0x11d/0x150 net/rxrpc/skbuff.c:78
rxrpc_cleanup_ring net/rxrpc/call_object.c:485 [inline]
rxrpc_release_call+0x5dd/0x860 net/rxrpc/call_object.c:552
rxrpc_release_calls_on_socket+0x21c/0x300 net/rxrpc/call_object.c:579
rxrpc_release_sock net/rxrpc/af_rxrpc.c:885 [inline]
rxrpc_release+0x263/0x5a0 net/rxrpc/af_rxrpc.c:916
__sock_release+0xcd/0x280 net/socket.c:597
...
The buggy address belongs to the object at ffff888011606dc0
which belongs to the cache skbuff_head_cache of size 232
Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Reported-by: syzbot+174de899852504e4a74a@syzkaller.appspotmail.com
Reported-by: syzbot+3d1c772efafd3c38d007@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hillf Danton <hdanton@sina.com>
Link: https://lore.kernel.org/r/161234207610.653119.5287360098400436976.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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: 5271953cad ("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>
The call state may be changed at any time by the data-ready routine in
response to received packets, so if the call state is to be read and acted
upon several times in a function, READ_ONCE() must be used unless the call
state lock is held.
As it happens, we used READ_ONCE() to read the state a few lines above the
unmarked read in rxrpc_input_data(), so use that value rather than
re-reading it.
Fixes: a158bdd324 ("rxrpc: Fix call timeouts")
Signed-off-by: Baptiste Lepers <baptiste.lepers@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/161046715522.2450566.488819910256264150.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Clang static analysis reports the following:
net/rxrpc/key.c:657:11: warning: Assigned value is garbage or undefined
toksize = toksizes[tok++];
^ ~~~~~~~~~~~~~~~
rxrpc_read() contains two consecutive loops. The first loop calculates the
token sizes and stores the results in toksizes[] and the second one uses
the array. When there is an error in identifying the token in the first
loop, the token is skipped, no change is made to the toksizes[] array.
When the same error happens in the second loop, the token is not skipped.
This will cause the toksizes[] array to be out of step and will overrun
past the calculated sizes.
Fix this by making both loops log a message and return an error in this
case. This should only happen if a new token type is incompletely
implemented, so it should normally be impossible to trigger this.
Fixes: 9a059cd5ca ("rxrpc: Downgrade the BUG() for unsupported token type in rxrpc_read()")
Reported-by: Tom Rix <trix@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/161046503122.2445787.16714129930607546635.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Replace a comma between expression statements by a semicolon.
Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Ask the security class how much header and trailer space to allow for when
allocating a packet, given how much data is remaining.
This will allow the rxgk security class to stick both a trailer in as well
as a header as appropriate in the future.
Signed-off-by: David Howells <dhowells@redhat.com>
In the rxkad security class, don't use pskb_pull() to advance through the
contents of the response packet. There's no point, especially as the next
and last access to the skbuff still has to allow for the wire header in the
offset (which we didn't advance over).
Better to just add the displacement to the next offset.
Signed-off-by: David Howells <dhowells@redhat.com>
Organise the security information in the rxrpc_connection struct to use a
union to allow for different data for different security classes.
Signed-off-by: David Howells <dhowells@redhat.com>
Insert the security header into the skbuff representing a DATA packet to be
transmitted rather than using skb_reserve() when the packet is allocated.
This makes it easier to apply crypto that spans the security header and the
data, particularly in the upcoming RxGK class where we have a common
encrypt-and-checksum function that is used in a number of circumstances.
Signed-off-by: David Howells <dhowells@redhat.com>
Merge the ->prime_packet_security() into the ->init_connection_security()
hook as they're always called together.
Signed-off-by: David Howells <dhowells@redhat.com>
When parsing a payload for an rxrpc-type key, ignore any tokens that are
not of a known type and don't give an error for them - unless there are no
tokens of a known type.
Signed-off-by: David Howells <dhowells@redhat.com>
Make the parsing of xdr-encoded payloads, as passed to add_key, more
coherent. Shuttling back and forth between various variables was a bit
hard to follow.
Signed-off-by: David Howells <dhowells@redhat.com>
Allow a security class to give more information on an rxrpc_s-type key when
it is viewed in /proc/keys. This will allow the upcoming RxGK security
class to show the enctype name here.
Signed-off-by: David Howells <dhowells@redhat.com>
Don't let someone reading a service-side rxrpc-type key get access to the
session key that was exchanged with the client. The server application
will, at some point, need to be able to read the information in the ticket,
but this probably shouldn't include the key material.
Signed-off-by: David Howells <dhowells@redhat.com>
Hand responsibility for parsing a server key off to the security class. We
can determine which class from the description. This is necessary as rxgk
server keys have different lookup requirements and different content
requirements (dependent on crypto type) to those of rxkad server keys.
Signed-off-by: David Howells <dhowells@redhat.com>
Split the server private key type (rxrpc_s) out into its own file rather
than mingling it with the authentication/client key type (rxrpc) since they
don't really bear any relation.
Signed-off-by: David Howells <dhowells@redhat.com>
Don't retain a pointer to the server key in the connection, but rather get
it on demand when the server has to deal with a response packet.
This is necessary to implement RxGK (GSSAPI-mediated transport class),
where we can't know which key we'll need until we've challenged the client
and got back the response.
This also means that we don't need to do a key search in the accept path in
softirq mode.
Also, whilst we're at it, allow the security class to ask for a kvno and
encoding-type variant of a server key as RxGK needs different keys for
different encoding types. Keys of this type have an extra bit in the
description:
"<service-id>:<security-index>:<kvno>:<enctype>"
Signed-off-by: David Howells <dhowells@redhat.com>
rxrpc-type keys can have multiple tokens attached for different security
classes. Currently, rxrpc always picks the first one, whether or not the
security class it indicates is supported.
Add preliminary support for choosing which security class will be used
(this will need to be directed from a higher layer) and go through the
tokens to find one that's supported.
Signed-off-by: David Howells <dhowells@redhat.com>
Fix the loss of transmission of a call's final ack when a socket gets shut
down. This means that the server will retransmit the last data packet or
send a ping ack and then get an ICMP indicating the port got closed. The
server will then view this as a failure.
Fixes: 3136ef49a1 ("rxrpc: Delay terminal ACK transmission on a client call")
Signed-off-by: David Howells <dhowells@redhat.com>
Fix rxrpc_unbundle_conn() to not drop the bundle usage count when cleaning
up an exclusive connection.
Based on the suggested fix from Hillf Danton.
Fixes: 245500d853 ("rxrpc: Rewrite the client connection manager")
Reported-by: syzbot+d57aaf84dd8a550e6d91@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hillf Danton <hdanton@sina.com>
Small conflict around locking in rxrpc_process_event() -
channel_lock moved to bundle in next, while state lock
needs _bh() from net.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
If someone calls setsockopt() twice to set a server key keyring, the first
keyring is leaked.
Fix it to return an error instead if the server key keyring is already set.
Fixes: 17926a7932 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: David Howells <dhowells@redhat.com>
The keyring containing the server's tokens isn't network-namespaced, so it
shouldn't be looked up with a network namespace. It is expected to be
owned specifically by the server, so namespacing is unnecessary.
Fixes: a58946c158 ("keys: Pass the network namespace into request_key mechanism")
Signed-off-by: David Howells <dhowells@redhat.com>
When a new incoming call arrives at an userspace rxrpc socket on a new
connection that has a security class set, the code currently pushes it onto
the accept queue to hold a ref on it for the socket. This doesn't work,
however, as recvmsg() pops it off, notices that it's in the SERVER_SECURING
state and discards the ref. This means that the call runs out of refs too
early and the kernel oopses.
By contrast, a kernel rxrpc socket manually pre-charges the incoming call
pool with calls that already have user call IDs assigned, so they are ref'd
by the call tree on the socket.
Change the mode of operation for userspace rxrpc server sockets to work
like this too. Although this is a UAPI change, server sockets aren't
currently functional.
Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
conn->state_lock may be taken in softirq mode, but a previous patch
replaced an outer lock in the response-packet event handling code, and lost
the _bh from that when doing so.
Fix this by applying the _bh annotation to the state_lock locking.
Fixes: a1399f8bb0 ("rxrpc: Call channels should have separate call number spaces")
Signed-off-by: David Howells <dhowells@redhat.com>
If rxrpc_read() (which allows KEYCTL_READ to read a key), sees a token of a
type it doesn't recognise, it can BUG in a couple of places, which is
unnecessary as it can easily get back to userspace.
Fix this to print an error message instead.
Fixes: 99455153d0 ("RxRPC: Parse security index 5 keys (Kerberos 5)")
Signed-off-by: David Howells <dhowells@redhat.com>
The session key should be encoded with just the 8 data bytes and
no length; ENCODE_DATA precedes it with a 4 byte length, which
confuses some existing tools that try to parse this format.
Add an ENCODE_BYTES macro that does not include a length, and use
it for the key. Also adjust the expected length.
Note that commit 774521f353 ("rxrpc: Fix an assertion in
rxrpc_read()") had fixed a BUG by changing the length rather than
fixing the encoding. The original length was correct.
Fixes: 99455153d0 ("RxRPC: Parse security index 5 keys (Kerberos 5)")
Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
When setting up a client connection, a second ref is accidentally obtained
on the connection bundle (we get one when allocating the conn and a second
one when adding the conn to the bundle).
Fix it to only use the ref obtained by rxrpc_alloc_client_connection() and
not to add a second when adding the candidate conn to the bundle.
Fixes: 245500d853 ("rxrpc: Rewrite the client connection manager")
Signed-off-by: David Howells <dhowells@redhat.com>
The alloc_error field in the rxrpc_bundle struct should be signed as it has
negative error codes assigned to it. Checks directly on it may then fail,
and may produce a warning like this:
net/rxrpc/conn_client.c:662 rxrpc_wait_for_channel()
warn: 'bundle->alloc_error' is unsigned
Fixes: 245500d853 ("rxrpc: Rewrite the client connection manager")
Reported-by Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Fix an error-handling goto in rxrpc_connect_call() whereby it will jump to
free the bundle it failed to allocate.
Fixes: 245500d853 ("rxrpc: Rewrite the client connection manager")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Allow the number of parallel connections to a machine to be expanded from a
single connection to a maximum of four. This allows up to 16 calls to be
in progress at the same time to any particular peer instead of 4.
Signed-off-by: David Howells <dhowells@redhat.com>
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>
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>
rxrpc_min_rtt_wlen is never used after it was introduced.
So better to remove it.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull networking fixes from David Miller:
1) Use netif_rx_ni() when necessary in batman-adv stack, from Jussi
Kivilinna.
2) Fix loss of RTT samples in rxrpc, from David Howells.
3) Memory leak in hns_nic_dev_probe(), from Dignhao Liu.
4) ravb module cannot be unloaded, fix from Yuusuke Ashizuka.
5) We disable BH for too lokng in sctp_get_port_local(), add a
cond_resched() here as well, from Xin Long.
6) Fix memory leak in st95hf_in_send_cmd, from Dinghao Liu.
7) Out of bound access in bpf_raw_tp_link_fill_link_info(), from
Yonghong Song.
8) Missing of_node_put() in mt7530 DSA driver, from Sumera
Priyadarsini.
9) Fix crash in bnxt_fw_reset_task(), from Michael Chan.
10) Fix geneve tunnel checksumming bug in hns3, from Yi Li.
11) Memory leak in rxkad_verify_response, from Dinghao Liu.
12) In tipc, don't use smp_processor_id() in preemptible context. From
Tuong Lien.
13) Fix signedness issue in mlx4 memory allocation, from Shung-Hsi Yu.
14) Missing clk_disable_prepare() in gemini driver, from Dan Carpenter.
15) Fix ABI mismatch between driver and firmware in nfp, from Louis
Peens.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (110 commits)
net/smc: fix sock refcounting in case of termination
net/smc: reset sndbuf_desc if freed
net/smc: set rx_off for SMCR explicitly
net/smc: fix toleration of fake add_link messages
tg3: Fix soft lockup when tg3_reset_task() fails.
doc: net: dsa: Fix typo in config code sample
net: dp83867: Fix WoL SecureOn password
nfp: flower: fix ABI mismatch between driver and firmware
tipc: fix shutdown() of connectionless socket
ipv6: Fix sysctl max for fib_multipath_hash_policy
drivers/net/wan/hdlc: Change the default of hard_header_len to 0
net: gemini: Fix another missing clk_disable_unprepare() in probe
net: bcmgenet: fix mask check in bcmgenet_validate_flow()
amd-xgbe: Add support for new port mode
net: usb: dm9601: Add USB ID of Keenetic Plus DSL
vhost: fix typo in error message
net: ethernet: mlx4: Fix memory allocation in mlx4_buddy_init()
pktgen: fix error message with wrong function name
net: ethernet: ti: am65-cpsw: fix rmii 100Mbit link mode
cxgb4: fix thermal zone device registration
...
Fix a memory leak in rxkad_verify_response() whereby the response buffer
doesn't get freed if we fail to allocate a ticket buffer.
Fixes: ef68622da9 ("rxrpc: Handle temporary errors better in rxkad security")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix rxrpc_kernel_get_srtt() to indicate the validity of the returned
smoothed RTT. If we haven't had any valid samples yet, the SRTT isn't
useful.
Fixes: c410bf0193 ("rxrpc: Fix the excessive initial retransmission timeout")
Signed-off-by: David Howells <dhowells@redhat.com>
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>
