Its not enough to check for available tcp send space.

We also hold on to transmitted data for mptcp-level retransmits.
Right now we will send more and more data if the peer can ack data
at the tcp level fast enough, since that frees up tcp send buffer space.

But we also need to check that data was acked and reclaimed at the mptcp
level.

Therefore add needed check in mptcp_sendmsg, flush tcp data and
wait until more mptcp snd space becomes available if we are over the
limit.  Before we wait for more data, also make sure we start the
retransmit timer if we ran out of sndbuf space.

Otherwise there is a very small chance that we wait forever:

 * receiver is waiting for data
 * sender is blocked because mptcp socket buffer is full
 * at tcp level, all data was acked
 * mptcp-level snd_una was not updated, because last ack
   that acknowledged the last data packet carried an older
   MPTCP-ack.

Restarting the retransmit timer avoids this problem: if TCP
subflow is idle, data is retransmitted from the RTX queue.

New data will make the peer send a new, updated MPTCP-Ack.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Paolo noticed that ssk_check_wmem() has same pattern, so add/use
common helper for both places.
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Don't call drivers if nothing changed. Netlink code already
contains this logic.
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Reviewed-by: NMichal Kubecek <mkubecek@suse.cz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Having a channel config with no ability to RX or TX traffic is
clearly wrong. Check for this in the core so the drivers don't
have to.
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Reviewed-by: NMichal Kubecek <mkubecek@suse.cz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RFC8684 allows to send 32-bit DATA_ACKs as long as the peer is not
sending 64-bit data-sequence numbers. The 64-bit DSN is only there for
extreme scenarios when a very high throughput subflow is combined with a
long-RTT subflow such that the high-throughput subflow wraps around the
32-bit sequence number space within an RTT of the high-RTT subflow.

It is thus a rare scenario and we should try to use the 32-bit DATA_ACK
instead as long as possible. It allows to reduce the TCP-option overhead
by 4 bytes, thus makes space for an additional SACK-block. It also makes
tcpdumps much easier to read when the DSN and DATA_ACK are both either
32 or 64-bit.
Signed-off-by: NChristoph Paasch <cpaasch@apple.com>
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The goal is to be able to inherit the initial devconf parameters from the
current netns, ie the netns where this new netns has been created.

This is useful in a containers environment where /proc/sys is read only.
For example, if a pod is created with specifics devconf parameters and has
the capability to create netns, the user expects to get the same parameters
than his 'init_net', which is not the real init_net in this case.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, on MP_JOIN failure we reset the child
socket, but leave the request socket untouched.

tcp_check_req will deal with it according to the
'tcp_abort_on_overflow' sysctl value - by default the
req socket will stay alive.

The above leads to inconsistent behavior on MP JOIN
failure, and bad listener overflow accounting.

This patch addresses the issue leveraging the infrastructure
just introduced to ask the TCP stack to drop the req on
failure.

The child socket is not freed anymore by subflow_syn_recv_sock(),
instead it's moved to a dead state and will be disposed by the
next sock_put done by the TCP stack, so that listener overflow
accounting is not affected by MP JOIN failure.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NChristoph Paasch <cpaasch@apple.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move the steps to prepare an inet_connection_sock for
forced disposal inside a separate helper. No functional
changes inteded, this will just simplify the next patch.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NChristoph Paasch <cpaasch@apple.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

MP_JOIN subflows must not land into the accept queue.
Currently tcp_check_req() calls an mptcp specific helper
to detect such scenario.

Such helper leverages the subflow context to check for
MP_JOIN subflows. We need to deal also with MP JOIN
failures, even when the subflow context is not available
due allocation failure.

A possible solution would be changing the syn_recv_sock()
signature to allow returning a more descriptive action/
error code and deal with that in tcp_check_req().

Since the above need is MPTCP specific, this patch instead
uses a TCP request socket hole to add a MPTCP specific flag.
Such flag is used by the MPTCP syn_recv_sock() to tell
tcp_check_req() how to deal with the request socket.

This change is a no-op for !MPTCP build, and makes the
MPTCP code simpler. It allows also the next patch to deal
correctly with MP JOIN failure.

v1 -> v2:
 - be more conservative on drop_req initialization (Mat)

RFC -> v1:
 - move the drop_req bit inside tcp_request_sock (Eric)
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Reviewed-by: NChristoph Paasch <cpaasch@apple.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Implement tcf_proto_ops->terse_dump() callback for flower classifier. Only
dump handle, flags and action data in terse mode.
Signed-off-by: NVlad Buslov <vladbu@mellanox.com>
Reviewed-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Extend tcf_action_dump() with boolean argument 'terse' that is used to
request terse-mode action dump. In terse mode only essential data needed to
identify particular action (action kind, cookie, etc.) and its stats is put
to resulting skb and everything else is omitted. Implement
tcf_exts_terse_dump() helper in cls API that is intended to be used to
request terse dump of all exts (actions) attached to the filter.
Signed-off-by: NVlad Buslov <vladbu@mellanox.com>
Reviewed-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add new TCA_DUMP_FLAGS attribute and use it in cls API to request terse
filter output from classifiers with TCA_DUMP_FLAGS_TERSE flag. This option
is intended to be used to improve performance of TC filter dump when
userland only needs to obtain stats and not the whole classifier/action
data. Extend struct tcf_proto_ops with new terse_dump() callback that must
be defined by supporting classifier implementations.

Support of the options in specific classifiers and actions is
implemented in following patches in the series.
Signed-off-by: NVlad Buslov <vladbu@mellanox.com>
Reviewed-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The assumption that a device node is associated either with the
netdev's device, or the parent of that device, does not hold for all
drivers. E.g. Freescale's DPAA has two layers of platform devices
above the netdev. Instead, recursively walk up the tree from the
netdev, allowing any parent to match against the sought after node.
Signed-off-by: NTobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Implement permissions as stated in uapi/linux/capability.h
In order to do that the verifier allow_ptr_leaks flag is split
into four flags and they are set as:
  env->allow_ptr_leaks = bpf_allow_ptr_leaks();
  env->bypass_spec_v1 = bpf_bypass_spec_v1();
  env->bypass_spec_v4 = bpf_bypass_spec_v4();
  env->bpf_capable = bpf_capable();

The first three currently equivalent to perfmon_capable(), since leaking kernel
pointers and reading kernel memory via side channel attacks is roughly
equivalent to reading kernel memory with cap_perfmon.

'bpf_capable' enables bounded loops, precision tracking, bpf to bpf calls and
other verifier features. 'allow_ptr_leaks' enable ptr leaks, ptr conversions,
subtraction of pointers. 'bypass_spec_v1' disables speculative analysis in the
verifier, run time mitigations in bpf array, and enables indirect variable
access in bpf programs. 'bypass_spec_v4' disables emission of sanitation code
by the verifier.

That means that the networking BPF program loaded with CAP_BPF + CAP_NET_ADMIN
will have speculative checks done by the verifier and other spectre mitigation
applied. Such networking BPF program will not be able to leak kernel pointers
and will not be able to access arbitrary kernel memory.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200513230355.7858-3-alexei.starovoitov@gmail.com

Update the memory requirements, when adding xdp.frame_sz in BPF test_run
function bpf_prog_test_run_xdp() which e.g. is used by XDP selftests.

Specifically add the expected reserved tailroom, but also allocated a
larger memory area to reflect that XDP frames usually comes in this
format. Limit the provided packet data size to 4096 minus headroom +
tailroom, as this also reflect a common 3520 bytes MTU limit with XDP.

Note that bpf_test_init already use a memory allocation method that clears
memory.  Thus, this already guards against leaking uninit kernel memory.
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/158945349549.97035.15316291762482444006.stgit@firesoul

Clearing memory of tail when grow happens, because it is too easy
to write a XDP_PASS program that extend the tail, which expose
this memory to users that can run tcpdump.
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/158945349039.97035.5262100484553494.stgit@firesoul

Finally, after all drivers have a frame size, allow BPF-helper
bpf_xdp_adjust_tail() to grow or extend packet size at frame tail.

Remember that helper/macro xdp_data_hard_end have reserved some
tailroom.  Thus, this helper makes sure that the BPF-prog don't have
access to this tailroom area.

V2: Remove one chicken check and use WARN_ONCE for other
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/158945348530.97035.12577148209134239291.stgit@firesoul

Use hole in struct xdp_frame, when adding member frame_sz, which keeps
same sizeof struct (32 bytes)

Drivers ixgbe and sfc had bug cases where the necessary/expected
tailroom was not reserved. This can lead to some hard to catch memory
corruption issues. Having the drivers frame_sz this can be detected when
packet length/end via xdp->data_end exceed the xdp_data_hard_end
pointer, which accounts for the reserved the tailroom.

When detecting this driver issue, simply fail the conversion with NULL,
which results in feedback to driver (failing xdp_do_redirect()) causing
driver to drop packet. Given the lack of consistent XDP stats, this can
be hard to troubleshoot. And given this is a driver bug, we want to
generate some more noise in form of a WARN stack dump (to ID the driver
code that inlined convert_to_xdp_frame).

Inlining the WARN macro is problematic, because it adds an asm
instruction (on Intel CPUs ud2) what influence instruction cache
prefetching. Thus, introduce xdp_warn and macro XDP_WARN, to avoid this
and at the same time make identifying the function and line of this
inlined function easier.
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/158945337313.97035.10015729316710496600.stgit@firesoul

The SKB "head" pointer points to the data area that contains
skb_shared_info, that can be found via skb_end_pointer(). Given
xdp->data_hard_start have been established (basically pointing to
skb->head), frame size is between skb_end_pointer() and data_hard_start,
plus the size reserved to skb_shared_info.

Change the bpf_xdp_adjust_tail offset adjust of skb->len, to be a positive
offset number on grow, and negative number on shrink.  As this seems more
natural when reading the code.
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/158945336804.97035.7164852191163722056.stgit@firesoul

With having ability to lookup sockets in cgroup skb programs it becomes
useful to access cgroup id of retrieved sockets so that policies can be
implemented based on origin cgroup of such socket.

For example, a container running in a cgroup can have cgroup skb ingress
program that can lookup peer socket that is sending packets to a process
inside the container and decide whether those packets should be allowed
or denied based on cgroup id of the peer.

More specifically such ingress program can implement intra-host policy
"allow incoming packets only from this same container and not from any
other container on same host" w/o relying on source IP addresses since
quite often it can be the case that containers share same IP address on
the host.

Introduce two new helpers for this use-case: bpf_sk_cgroup_id() and
bpf_sk_ancestor_cgroup_id().

These helpers are similar to existing bpf_skb_{,ancestor_}cgroup_id
helpers with the only difference that sk is used to get cgroup id
instead of skb, and share code with them.

See documentation in UAPI for more details.
Signed-off-by: NAndrey Ignatov <rdna@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/f5884981249ce911f63e9b57ecd5d7d19154ff39.1589486450.git.rdna@fb.com

cgroup skb programs already can use bpf_skb_cgroup_id. Allow
bpf_skb_ancestor_cgroup_id as well so that container policies can be
implemented for a container that can have sub-cgroups dynamically
created, but policies should still be implemented based on cgroup id of
container itself not on an id of a sub-cgroup.
Signed-off-by: NAndrey Ignatov <rdna@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/8874194d6041eba190356453ea9f6071edf5f658.1589486450.git.rdna@fb.com

Currently sk lookup helpers are allowed in tc, xdp, sk skb, and cgroup
sock_addr programs.

But they would be useful in cgroup skb as well so that for example
cgroup skb ingress program can lookup a peer socket a packet comes from
on same host and make a decision whether to allow or deny this packet
based on the properties of that socket, e.g. cgroup that peer socket
belongs to.

Allow the following sk lookup helpers in cgroup skb:
* bpf_sk_lookup_tcp;
* bpf_sk_lookup_udp;
* bpf_sk_release;
* bpf_skc_lookup_tcp.
Signed-off-by: NAndrey Ignatov <rdna@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/f8c7ee280f1582b586629436d777b6db00597d63.1589486450.git.rdna@fb.com

bpf_sock_addr.user_port supports only 4-byte load and it leads to ugly
code in BPF programs, like:

	volatile __u32 user_port = ctx->user_port;
	__u16 port = bpf_ntohs(user_port);

Since otherwise clang may optimize the load to be 2-byte and it's
rejected by verifier.

Add support for 1- and 2-byte loads same way as it's supported for other
fields in bpf_sock_addr like user_ip4, msg_src_ip4, etc.
Signed-off-by: NAndrey Ignatov <rdna@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/c1e983f4c17573032601d0b2b1f9d1274f24bc16.1589420814.git.rdna@fb.com

During the initialization process, ipmr_new_table() is called
to create new tables which in turn calls ipmr_get_table() which
traverses net->ipv4.mr_tables without holding the writer lock.
However, this is safe to do so as no tables exist at this time.
Hence add a suitable lockdep expression to silence the following
false-positive warning:

=============================
WARNING: suspicious RCU usage
5.7.0-rc3-next-20200428-syzkaller #0 Not tainted
-----------------------------
net/ipv4/ipmr.c:136 RCU-list traversed in non-reader section!!

ipmr_get_table+0x130/0x160 net/ipv4/ipmr.c:136
ipmr_new_table net/ipv4/ipmr.c:403 [inline]
ipmr_rules_init net/ipv4/ipmr.c:248 [inline]
ipmr_net_init+0x133/0x430 net/ipv4/ipmr.c:3089

Fixes: f0ad0860 ("ipv4: ipmr: support multiple tables")
Reported-by: syzbot+1519f497f2f9f08183c6@syzkaller.appspotmail.com
Suggested-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NAmol Grover <frextrite@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ipmr_for_each_table() macro uses list_for_each_entry_rcu()
for traversing outside of an RCU read side critical section
but under the protection of rtnl_mutex. Hence, add the
corresponding lockdep expression to silence the following
false-positive warning at boot:

[    4.319347] =============================
[    4.319349] WARNING: suspicious RCU usage
[    4.319351] 5.5.4-stable #17 Tainted: G            E
[    4.319352] -----------------------------
[    4.319354] net/ipv4/ipmr.c:1757 RCU-list traversed in non-reader section!!

Fixes: f0ad0860 ("ipv4: ipmr: support multiple tables")
Signed-off-by: NAmol Grover <frextrite@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Clean up after recent fixes, move address calculations
around and change the variable init, so that we can have
just one start_offset == end_offset check.

Make the check a little stricter to preserve the -EINVAL
error if requested start offset is larger than the region
itself.
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If user provides wrong virtual address in TCP_ZEROCOPY_RECEIVE
operation we want to return -EINVAL error.

But depending on zc->recv_skip_hint content, we might return
-EIO error if the socket has SOCK_DONE set.

Make sure to return -EINVAL in this case.

BUG: KMSAN: uninit-value in tcp_zerocopy_receive net/ipv4/tcp.c:1833 [inline]
BUG: KMSAN: uninit-value in do_tcp_getsockopt+0x4494/0x6320 net/ipv4/tcp.c:3685
CPU: 1 PID: 625 Comm: syz-executor.0 Not tainted 5.7.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x220 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
 tcp_zerocopy_receive net/ipv4/tcp.c:1833 [inline]
 do_tcp_getsockopt+0x4494/0x6320 net/ipv4/tcp.c:3685
 tcp_getsockopt+0xf8/0x1f0 net/ipv4/tcp.c:3728
 sock_common_getsockopt+0x13f/0x180 net/core/sock.c:3131
 __sys_getsockopt+0x533/0x7b0 net/socket.c:2177
 __do_sys_getsockopt net/socket.c:2192 [inline]
 __se_sys_getsockopt+0xe1/0x100 net/socket.c:2189
 __x64_sys_getsockopt+0x62/0x80 net/socket.c:2189
 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c829
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f1deeb72c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00000000004e01e0 RCX: 000000000045c829
RDX: 0000000000000023 RSI: 0000000000000006 RDI: 0000000000000009
RBP: 000000000078bf00 R08: 0000000020000200 R09: 0000000000000000
R10: 00000000200001c0 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000001d8 R14: 00000000004d3038 R15: 00007f1deeb736d4

Local variable ----zc@do_tcp_getsockopt created at:
 do_tcp_getsockopt+0x1a74/0x6320 net/ipv4/tcp.c:3670
 do_tcp_getsockopt+0x1a74/0x6320 net/ipv4/tcp.c:3670

Fixes: 05255b82 ("tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While do_ipv6_getsockopt does not call the high-level recvmsg helper,
the msghdr eventually ends up being passed to put_cmsg anyway, and thus
needs msg_control_is_user set to the proper value.

Fixes: 1f466e1f ("net: cleanly handle kernel vs user buffers for ->msg_control")
Reported-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a service subscription is expired or canceled by user, it needs to
be deleted from the subscription list, so that new subscriptions can be
registered (max = 65535 per net). However, there are two issues in code
that can cause such an unused subscription to persist:

1) The 'tipc_conn_delete_sub()' has a loop on the subscription list but
it makes a break shortly when the 1st subscription differs from the one
specified, so the subscription will not be deleted.

2) In case a subscription is canceled, the code to remove the
'TIPC_SUB_CANCEL' flag from the subscription filter does not work if it
is a local subscription (i.e. the little endian isn't involved). So, it
will be no matches when looking for the subscription to delete later.

The subscription(s) will be removed eventually when the user terminates
its topology connection but that could be a long time later. Meanwhile,
the number of available subscriptions may be exhausted.

This commit fixes the two issues above, so as needed a subscription can
be deleted correctly.
Acked-by: NYing Xue <ying.xue@windriver.com>
Acked-by: NJon Maloy <jmaloy@redhat.com>
Signed-off-by: NTuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Upon receipt of a service subscription request from user via a topology
connection, one 'sub' object will be allocated in kernel, so it will be
able to send an event of the service if any to the user correspondingly
then. Also, in case of any failure, the connection will be shutdown and
all the pertaining 'sub' objects will be freed.

However, there is a race condition as follows resulting in memory leak:

       receive-work       connection        send-work
              |                |                |
        sub-1 |<------//-------|                |
        sub-2 |<------//-------|                |
              |                |<---------------| evt for sub-x
        sub-3 |<------//-------|                |
              :                :                :
              :                :                :
              |       /--------|                |
              |       |        * peer closed    |
              |       |        |                |
              |       |        |<-------X-------| evt for sub-y
              |       |        |<===============|
        sub-n |<------/        X    shutdown    |
    -> orphan |                                 |

That is, the 'receive-work' may get the last subscription request while
the 'send-work' is shutting down the connection due to peer close.

We had a 'lock' on the connection, so the two actions cannot be carried
out simultaneously. If the last subscription is allocated e.g. 'sub-n',
before the 'send-work' closes the connection, there will be no issue at
all, the 'sub' objects will be freed. In contrast the last subscription
will become orphan since the connection was closed, and we released all
references.

This commit fixes the issue by simply adding one test if the connection
remains in 'connected' state right after we obtain the connection lock,
then a subscription object can be created as usual, otherwise we ignore
it.
Acked-by: NYing Xue <ying.xue@windriver.com>
Acked-by: NJon Maloy <jmaloy@redhat.com>
Reported-by: NThang Ngo <thang.h.ngo@dektech.com.au>
Signed-off-by: NTuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently when a connection is in Nagle mode, we set the 'ack_required'
bit in the last sending buffer and wait for the corresponding ACK prior
to pushing more data. However, on the receiving side, the ACK is issued
only when application really  reads the whole data. Even if part of the
last buffer is received, we will not do the ACK as required. This might
cause an unnecessary delay since the receiver does not always fetch the
message as fast as the sender, resulting in a large latency in the user
message sending, which is: [one RTT + the receiver processing time].

The commit makes Nagle ACK as soon as possible i.e. when a message with
the 'ack_required' arrives in the receiving side's stack even before it
is processed or put in the socket receive queue...
This way, we can limit the streaming latency to one RTT as committed in
Nagle mode.
Acked-by: NYing Xue <ying.xue@windriver.com>
Acked-by: NJon Maloy <jmaloy@redhat.com>
Signed-off-by: NTuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The code had historically been ignoring these errors, and my recent
refactoring changed that, which broke ssh in some setups.

Fixes: 2618d530 ("net/scm: cleanup scm_detach_fds")
Reported-by: NIdo Schimmel <idosch@idosch.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Tested-by: NIdo Schimmel <idosch@mellanox.com>
Tested-by: NIoana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit b121b341 ("bpf: Add PTR_TO_BTF_ID_OR_NULL
support") adds a field btf_id_or_null_non0_off to
bpf_prog->aux structure to indicate that the
first ctx argument is PTR_TO_BTF_ID reg_type and
all others are PTR_TO_BTF_ID_OR_NULL.
This approach does not really scale if we have
other different reg types in the future, e.g.,
a pointer to a buffer.

This patch enables bpf_iter targets registering ctx argument
reg types which may be different from the default one.
For example, for pointers to structures, the default reg_type
is PTR_TO_BTF_ID for tracing program. The target can register
a particular pointer type as PTR_TO_BTF_ID_OR_NULL which can
be used by the verifier to enforce accesses.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200513180221.2949882-1-yhs@fb.com

Change func bpf_iter_unreg_target() parameter from target
name to target reg_info, similar to bpf_iter_reg_target().
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200513180220.2949737-1-yhs@fb.com

Currently bpf_iter_reg_target takes parameters from target
and allocates memory to save them. This is really not
necessary, esp. in the future we may grow information
passed from targets to bpf_iter manager.

The patch refactors the code so target reg_info
becomes static and bpf_iter manager can just take
a reference to it.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200513180219.2949605-1-yhs@fb.com

Whenever we disconnect a L2CAP connection, we would immediately
report a disconnection event (EPOLLHUP) to the upper layer, without
waiting for the response of the other device.

This patch offers an option to wait until we receive a disconnection
response before reporting disconnection event, by using the "how"
parameter in l2cap_sock_shutdown(). Therefore, upper layer can opt
to wait for disconnection response by shutdown(sock, SHUT_WR).

This can be used to enforce proper disconnection order in HID,
where the disconnection of the interrupt channel must be complete
before attempting to disconnect the control channel.
Signed-off-by: NArchie Pusaka <apusaka@chromium.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

After sending Inquiry Cancel command to the controller, it is possible
that Inquiry Complete event comes before Inquiry Cancel command complete
event. In this case the Inquiry Cancel command will have status of
Command Disallowed since there is no Inquiry session to be cancelled.
This case should not be treated as error, otherwise we can reach an
inconsistent state.

Example of a btmon trace when this happened:

< HCI Command: Inquiry Cancel (0x01|0x0002) plen 0
> HCI Event: Inquiry Complete (0x01) plen 1
        Status: Success (0x00)
> HCI Event: Command Complete (0x0e) plen 4
      Inquiry Cancel (0x01|0x0002) ncmd 1
        Status: Command Disallowed (0x0c)
Signed-off-by: NSonny Sasaka <sonnysasaka@chromium.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Let drivers have a hook to disable configuring scanning during suspend.
Drivers should use the device_may_wakeup function call to determine
whether hci should be configured for wakeup.

For example, an implementation for btusb may look like the following:

  bool btusb_prevent_wake(struct hci_dev *hdev)
  {
        struct btusb_data *data = hci_get_drvdata(hdev);
        return !device_may_wakeup(&data->udev->dev);
  }
Signed-off-by: NAbhishek Pandit-Subedi <abhishekpandit@chromium.org>
Reviewed-by: NAlain Michaud <alainm@chromium.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Renamed BT_SUSPEND_COMPLETE to BT_SUSPEND_CONFIGURE_WAKE since it sets
up the event filter and whitelist for wake-up.
Signed-off-by: NAbhishek Pandit-Subedi <abhishekpandit@chromium.org>
Reviewed-by: NAlain Michaud <alainm@chromium.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When a device is suspended, it doesn't need to be as responsive to
connection events. Increase the interval to 640ms (creating a duty cycle
of roughly 1.75%) so that passive scanning uses much less power (vs
previous duty cycle of 18.75%). The new window + interval combination
has been tested to work with HID devices (which are currently the only
devices capable of wake up).
Signed-off-by: NAbhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>