Alain Michaud [Thu, 11 Jun 2020 19:50:41 +0000 (19:50 +0000)]
Bluetooth: Add support for BT_PKT_STATUS CMSG data for SCO connections
This change adds support for reporting the BT_PKT_STATUS to the socket
CMSG data to allow the implementation of a packet loss correction on
erroneous data received on the SCO socket.
The patch was partially developed by Marcel Holtmann and validated by
Hsin-yu Chao.
Use device_init_wakeup to allow the Bluetooth dev to wake the system
from suspend. Currently, the device can wake the system but no
power/wakeup entry is created in sysfs to allow userspace to disable
wakeup.
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Use the parent device's power/wakeup to control whether we support
remote wake. If remote wakeup is disabled, Bluetooth will not enable
scanning for incoming connections.
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Set the correct parent dev when registering hdev. This allows userspace
tools to find the parent device (for example, to set the power/wakeup
property).
Before this change, the path was /sys/devices/virtual/bluetooth/hci0
and after this change, it looks more like:
/sys/bus/mmc/devices/mmc1:0001/mmc1:0001:2/bluetooth/hci0
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Due to race conditions between qca_hw_error and qca_controller_memdump
during SSR timeout,the same pointer is freed twice. This results in a
double free. Now a lock is acquired before checking the stauts of SSR
state.
Bluetooth: Allow suspend even when preparation has failed
It is preferable to allow suspend even when Bluetooth has problems
preparing for sleep. When Bluetooth fails to finish preparing for
suspend, log the error and allow the suspend notifier to continue
instead.
To also make it clearer why suspend failed, change bt_dev_dbg to
bt_dev_err when handling the suspend timeout.
Fixes: dd522a7429b07e ("Bluetooth: Handle LE devices during suspend") Reported-by: Len Brown <len.brown@intel.com> Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: hci_qca: Refactor error handling in qca_suspend()
If waiting for IBS sleep times out jump to the error handler, this is
easier to read than multiple 'if' branches and a fall through to the
error handler.
Bluetooth: hci_qca: Skip serdev wait when no transfer is pending
qca_suspend() calls serdev_device_wait_until_sent() regardless of
whether a transfer is pending. While it does no active harm since
the function should return immediately it makes the code more
confusing. Add a flag to track whether a transfer is pending and
only call serdev_device_wait_until_sent() is needed.
Bluetooth: hci_qca: Only remove TX clock vote after TX is completed
qca_suspend() removes the vote for the UART TX clock after
writing an IBS sleep request to the serial buffer. This is
not a good idea since there is no guarantee that the request
has been sent at this point. Instead remove the vote after
successfully entering IBS sleep. This also fixes the issue
of the vote being removed in case of an aborted suspend due
to a failure of entering IBS sleep.
Bluetooth: hci_qca: Simplify determination of serial clock on/off state from votes
The serial clocks should be on when there is a vote for at least one
of the clocks (RX or TX), and off when there is no 'on' vote. The
current logic to determine the combined state is a bit redundant
in the code paths for different types of votes, use a single
statement in the common path instead.
Dan Carpenter [Fri, 29 May 2020 09:59:48 +0000 (12:59 +0300)]
Bluetooth: hci_qca: Fix an error pointer dereference
When a function like devm_clk_get_optional() function returns both error
pointers on error and NULL then the NULL return means that the optional
feature is deliberately disabled. It is a special sort of success and
should not trigger an error message. The surrounding code should be
written to check for NULL and not crash.
On the other hand, if we encounter an error, then the probe from should
clean up and return a failure.
In this code, if devm_clk_get_optional() returns an error pointer then
the kernel will crash inside the call to:
clk_set_rate(qcadev->susclk, SUSCLK_RATE_32KHZ);
The error handling must be updated to prevent that.
Fixes: 77131dfec6af ("Bluetooth: hci_qca: Replace devm_gpiod_get() with devm_gpiod_get_optional()") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Alain Michaud [Mon, 1 Jun 2020 14:20:59 +0000 (14:20 +0000)]
Bluetooth: Removing noisy dbg message
This patch removes a particularly noisy dbg message. The debug message
isn't particularly interesting for debuggability so it was simply
removed to reduce noise in dbg logs.
When running with conntrack rules, the dropped overlap fragments may cause
EPERM to be returned to sendto. Instead of completely failing, just ignore
those errors and continue. If this causes packets with overlap fragments to
be dropped as expected, that is okay. And if it causes packets that are
expected to be received to be dropped, which should not happen, it will be
detected as failure.
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Vasily Averin [Tue, 2 Jun 2020 12:55:26 +0000 (15:55 +0300)]
net_failover: fixed rollback in net_failover_open()
found by smatch:
drivers/net/net_failover.c:65 net_failover_open() error:
we previously assumed 'primary_dev' could be null (see line 43)
Fixes: cfc80d9a1163 ("net: Introduce net_failover driver") Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Signed-off-by: David S. Miller <davem@davemloft.net>
There is no actual tipc_node refcnt leak as stated in the above commit.
The refcnt is hold carefully for the case of an asynchronous decryption
(i.e. -EINPROGRESS/-EBUSY and skb = NULL is returned), so that the node
object cannot be freed in the meantime. The counter will be re-balanced
when the operation's callback arrives with the decrypted buffer if any.
In other cases, e.g. a synchronous crypto the counter will be decreased
immediately when it is done.
Now with that commit, a kernel panic will occur when there is no node
found (i.e. n = NULL) in the 'tipc_rcv()' or a premature release of the
node object.
This commit solves the issues by reverting the said commit, but keeping
one valid case that the 'skb_linearize()' is failed.
Acked-by: Jon Maloy <jmaloy@redhat.com> Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au> Tested-by: Hoang Le <hoang.h.le@dektech.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Ronak Doshi [Tue, 2 Jun 2020 03:02:39 +0000 (20:02 -0700)]
vmxnet3: allow rx flow hash ops only when rss is enabled
It makes sense to allow changes to get/set rx flow hash callback only
when rss is enabled. This patch restricts get_rss_hash_opts and
set_rss_hash_opts methods to allow querying and configuring different
Rx flow hash configurations only when rss is enabled
Signed-off-by: Ronak Doshi <doshir@vmware.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Luo bin [Tue, 2 Jun 2020 00:40:32 +0000 (08:40 +0800)]
hinic: add set_channels ethtool_ops support
add support to change TX/RX queue number with "ethtool -L combined".
V5 -> V6: remove check for carrier in hinic_xmit_frame
V4 -> V5: change time zone in patch header
V3 -> V4: update date in patch header
V2 -> V3: remove check for zero channels->combined_count
V1 -> V2: update commit message("ethtool -L" to "ethtool -L combined")
V0 -> V1: remove check for channels->tx_count/rx_count/other_count
Signed-off-by: Luo bin <luobin9@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
When using make kselftest TARGETS=bpf, tools/bpf is built with
MAKEFLAGS=rR, which causes $(CXX) to be undefined, which in turn causes
the build to fail with
CXX test_cpp
/bin/sh: 2: g: not found
Fix by adding a default $(CXX) value, like tools/build/feature/Makefile
already does.
When using make kselftest TARGETS=bpf, tools/bpf is built with
MAKEFLAGS=rR, which causes $(COMPILE.c) to be undefined, which in turn
causes the build to fail with
CC kselftest/bpf/tools/build/bpftool/map_perf_ring.o
/bin/sh: 1: -MMD: not found
Fix by using $(CC) $(CFLAGS) -c instead of $(COMPILE.c).
Since commit 0ebeea8ca8a4 ("bpf: Restrict bpf_probe_read{, str}() only to
archs where they work") 44 verifier tests fail on s390 due to not having
bpf_probe_read anymore. Fix by using bpf_probe_read_kernel.
Certain kernel functions (e.g. get_vtimer/set_vtimer) cause kernel
panic when the stack is not 8-byte aligned. Currently JITed BPF programs
may trigger this by allocating stack frames with non-rounded sizes and
then being interrupted. Fix by using rounded fp->aux->stack_depth.
Andrii Nakryiko [Tue, 2 Jun 2020 05:03:49 +0000 (22:03 -0700)]
selftests/bpf: Fix sample_cnt shared between two threads
Make sample_cnt volatile to fix possible selftests failure due to compiler
optimization preventing latest sample_cnt value to be visible to main thread.
sample_cnt is incremented in background thread, which is then joined into main
thread. So in terms of visibility sample_cnt update is ok. But because it's
not volatile, compiler might make optimizations that would prevent main thread
to see latest updated value. Fix this by marking global variable volatile.
====================
This series fixes an issue originally reported by Lorenz Bauer where using
the bpf_skb_adjust_room() helper hid a checksum bug since it wasn't adjusting
CHECKSUM_UNNECESSARY's skb->csum_level after decap. The fix is two-fold:
i) We do a safe reset in bpf_skb_adjust_room() to CHECKSUM_NONE with an opt-
out flag BPF_F_ADJ_ROOM_NO_CSUM_RESET.
ii) We add a new bpf_csum_level() for the latter in order to allow users to
manually inc/dec the skb->csum_level when needed.
The series is rebased against latest bpf-next tree. It can be applied there,
or to bpf after the merge win sync from net-next.
Daniel Borkmann [Tue, 2 Jun 2020 14:58:34 +0000 (16:58 +0200)]
bpf, selftests: Adapt cls_redirect to call csum_level helper
Adapt bpf_skb_adjust_room() to pass in BPF_F_ADJ_ROOM_NO_CSUM_RESET flag and
use the new bpf_csum_level() helper to inc/dec the checksum level by one after
the encap/decap.
Daniel Borkmann [Tue, 2 Jun 2020 14:58:33 +0000 (16:58 +0200)]
bpf: Add csum_level helper for fixing up csum levels
Add a bpf_csum_level() helper which BPF programs can use in combination
with bpf_skb_adjust_room() when they pass in BPF_F_ADJ_ROOM_NO_CSUM_RESET
flag to the latter to avoid falling back to CHECKSUM_NONE.
The bpf_csum_level() allows to adjust CHECKSUM_UNNECESSARY skb->csum_levels
via BPF_CSUM_LEVEL_{INC,DEC} which calls __skb_{incr,decr}_checksum_unnecessary()
on the skb. The helper also allows a BPF_CSUM_LEVEL_RESET which sets the skb's
csum to CHECKSUM_NONE as well as a BPF_CSUM_LEVEL_QUERY to just return the
current level. Without this helper, there is no way to otherwise adjust the
skb->csum_level. I did not add an extra dummy flags as there is plenty of free
bitspace in level argument itself iff ever needed in future.
Daniel Borkmann [Tue, 2 Jun 2020 14:58:32 +0000 (16:58 +0200)]
bpf: Fix up bpf_skb_adjust_room helper's skb csum setting
Lorenz recently reported:
In our TC classifier cls_redirect [0], we use the following sequence of
helper calls to decapsulate a GUE (basically IP + UDP + custom header)
encapsulated packet:
It seems like some checksums of the inner headers are not validated in
this case. For example, a TCP SYN packet with invalid TCP checksum is
still accepted by the network stack and elicits a SYN ACK. [...]
That is, we receive the following packet from the driver:
| ETH | IP | UDP | GUE | IP | TCP |
skb->ip_summed == CHECKSUM_UNNECESSARY
ip_summed is CHECKSUM_UNNECESSARY because our NICs do rx checksum offloading.
On this packet we run skb_adjust_room_mac(-encap_len), and get the following:
| ETH | IP | TCP |
skb->ip_summed == CHECKSUM_UNNECESSARY
Note that ip_summed is still CHECKSUM_UNNECESSARY. After bpf_redirect()'ing
into the ingress, we end up in tcp_v4_rcv(). There, skb_checksum_init() is
turned into a no-op due to CHECKSUM_UNNECESSARY.
The bpf_skb_adjust_room() helper is not aware of protocol specifics. Internally,
it handles the CHECKSUM_COMPLETE case via skb_postpull_rcsum(), but that does
not cover CHECKSUM_UNNECESSARY. In this case skb->csum_level of the original
skb prior to bpf_skb_adjust_room() call was 0, that is, covering UDP. Right now
there is no way to adjust the skb->csum_level. NICs that have checksum offload
disabled (CHECKSUM_NONE) or that support CHECKSUM_COMPLETE are not affected.
Use a safe default for CHECKSUM_UNNECESSARY by resetting to CHECKSUM_NONE and
add a flag to the helper called BPF_F_ADJ_ROOM_NO_CSUM_RESET that allows users
from opting out. Opting out is useful for the case where we don't remove/add
full protocol headers, or for the case where a user wants to adjust the csum
level manually e.g. through bpf_csum_level() helper that is added in subsequent
patch.
The bpf_skb_proto_{4_to_6,6_to_4}() for NAT64/46 translation from the BPF
bpf_skb_change_proto() helper uses bpf_skb_net_hdr_{push,pop}() pair internally
as well but doesn't change layers, only transitions between v4 to v6 and vice
versa, therefore no adoption is required there.
Jules Irenge [Mon, 1 Jun 2020 18:45:52 +0000 (19:45 +0100)]
sfc: add missing annotation for efx_ef10_try_update_nic_stats_vf()
Sparse reports a warning at efx_ef10_try_update_nic_stats_vf()
warning: context imbalance in efx_ef10_try_update_nic_stats_vf()
- unexpected unlock
The root cause is the missing annotation at
efx_ef10_try_update_nic_stats_vf()
Add the missing _must_hold(&efx->stats_lock) annotation
Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Ayush Sawal [Mon, 1 Jun 2020 17:41:59 +0000 (23:11 +0530)]
Crypto/chcr: Fixes a coccinile check error
This fixes an error observed after running coccinile check.
drivers/crypto/chelsio/chcr_algo.c:1462:5-8: Unneeded variable:
"err". Return "0" on line 1480
This line is missed in the commit 567be3a5d227 ("crypto:
chelsio - Use multiple txq/rxq per tfm to process the requests").
Fixes: 567be3a5d227 ("crypto:
chelsio - Use multiple txq/rxq per tfm to process the requests").
V1->V2
-Modified subject.
Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Ayush Sawal [Mon, 1 Jun 2020 17:41:58 +0000 (23:11 +0530)]
Crypto/chcr: Fixes compilations warnings
This patch fixes the compilation warnings displayed by sparse tool for
chcr driver.
V1->V2
Avoid type casting by using get_unaligned_be32() and
put_unaligned_be16/32() functions.
The key which comes from stack is an u8 byte stream so we store it in
an unsigned char array(ablkctx->key). The function get_aes_decrypt_key()
is a used to calculate the reverse round key for decryption, for this
operation the key has to be divided into 4 bytes, so to extract 4 bytes
from an u8 byte stream and store it in an u32 variable, get_aligned_be32()
is used. Similarly for copying back the key from u32 variable to the
original u8 key stream, put_aligned_be32() is used.
Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Current design enables ktls setting from start, which is not
efficient. Now the feature will be enabled when user demands
TLS offload on any interface.
v1->v2:
- taking ULD module refcount till any single connection exists.
- taking rtnl_lock() before clearing tls_devops.
v2->v3:
- cxgb4 is now registering to tlsdev_ops.
- module refcount inc/dec in chcr.
- refcount is only for connections.
- removed new code from cxgb_set_feature().
v3->v4:
- fixed warning message.
Signed-off-by: Rohit Maheshwari <rohitm@chelsio.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Hangbin Liu [Mon, 1 Jun 2020 03:55:03 +0000 (11:55 +0800)]
ipv6: fix IPV6_ADDRFORM operation logic
Socket option IPV6_ADDRFORM supports UDP/UDPLITE and TCP at present.
Previously the checking logic looks like:
if (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_UDPLITE)
do_some_check;
else if (sk->sk_protocol != IPPROTO_TCP)
break;
After commit b6f6118901d1 ("ipv6: restrict IPV6_ADDRFORM operation"), TCP
was blocked as the logic changed to:
if (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_UDPLITE)
do_some_check;
else if (sk->sk_protocol == IPPROTO_TCP)
do_some_check;
break;
else
break;
Then after commit 82c9ae440857 ("ipv6: fix restrict IPV6_ADDRFORM operation")
UDP/UDPLITE were blocked as the logic changed to:
if (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_UDPLITE)
do_some_check;
if (sk->sk_protocol == IPPROTO_TCP)
do_some_check;
if (sk->sk_protocol != IPPROTO_TCP)
break;
Fix it by using Eric's code and simply remove the break in TCP check, which
looks like:
if (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_UDPLITE)
do_some_check;
else if (sk->sk_protocol == IPPROTO_TCP)
do_some_check;
else
break;
Fixes: 82c9ae440857 ("ipv6: fix restrict IPV6_ADDRFORM operation") Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
YueHaibing [Thu, 28 May 2020 14:34:07 +0000 (22:34 +0800)]
tipc: Fix NULL pointer dereference in __tipc_sendstream()
tipc_sendstream() may send zero length packet, then tipc_msg_append()
do not alloc skb, skb_peek_tail() will get NULL, msg_set_ack_required
will trigger NULL pointer dereference.
Reported-by: syzbot+8eac6d030e7807c21d32@syzkaller.appspotmail.com Fixes: 0a3e060f340d ("tipc: add test for Nagle algorithm effectiveness") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
====================
One of the pieces of feedback from recent review of BPF hooks for socket
lookup [0] was that new program types should use bpf_link-based
attachment.
This series introduces new bpf_link type for attaching to network
namespace. All link operations are supported. Errors returned from ops
follow cgroup example. Patch 4 description goes into error semantics.
The major change in v2 is a switch away from RCU to mutex-only
synchronization. Andrii pointed out that it is not needed, and it makes
sense to keep locking straightforward.
Also, there were a couple of bugs in update_prog and fill_info initial
implementation, one picked up by kbuild. Those are now fixed. Tests have
been extended to cover them. Full changelog below.
Series is organized as so:
Patches 1-3 prepare a space in struct net to keep state for attached BPF
programs, and massage the code in flow_dissector to make it attach type
agnostic, to finally move it under kernel/bpf/.
Patch 4, the most important one, introduces new bpf_link link type for
attaching to network namespace.
Patch 5 unifies the update error (ENOLINK) between BPF cgroup and netns.
Patches 6-8 make libbpf and bpftool aware of the new link type.
Patches 9-12 Add and extend tests to check that link low- and high-level
API for operating on links to netns works as intended.
Thanks to Alexei, Andrii, Lorenz, Marek, and Stanislav for feedback.
- Switch to mutex-only synchronization. Don't rely on RCU grace period
guarantee when accessing struct net from link release / update /
fill_info, and when accessing bpf_link from pernet pre_exit
callback. (Andrii)
- Drop patch 1, no longer needed with mutex-only synchronization.
- Don't leak uninitialized variable contents from fill_info callback
when link is in defunct state. (kbuild)
- Make fill_info treat the link as defunct (i.e. no attached netns) when
struct net refcount is 0, but link has not been yet auto-detached.
- Add missing BPF_LINK_TYPE define in bpf_types.h for new link type.
- Fix link update_prog callback to update the prog that will run, and
not just the link itself.
- Return EEXIST on prog attach when link already exists, and on link
create when prog is already attached directly. (Andrii)
- Return EINVAL on prog detach when link is attached. (Andrii)
- Fold __netns_bpf_link_attach into its only caller. (Stanislav)
- Get rid of a wrapper around container_of() (Andrii)
- Use rcu_dereference_protected instead of rcu_access_pointer on
update-side. (Stanislav)
- Make return-on-success from netns_bpf_link_create less
confusing. (Andrii)
- Adapt bpf_link for cgroup to return ENOLINK when updating a defunct
link. (Andrii, Alexei)
- Order new exported symbols in libbpf.map alphabetically (Andrii)
- Keep libbpf's "failed to attach link" warning message clear as to what
we failed to attach to (cgroup vs netns). (Andrii)
- Extract helpers for printing link attach type. (bpftool, Andrii)
- Switch flow_dissector tests to BPF skeleton and extend them to
exercise link-based flow dissector attachment. (Andrii)
- Harden flow dissector attachment tests with prog query checks after
prog attach/detach, or link create/update/close.
- Extend flow dissector tests to cover fill_info for defunct links.
- Rebase onto recent bpf-next
====================
Jakub Sitnicki [Sun, 31 May 2020 08:28:46 +0000 (10:28 +0200)]
selftests/bpf: Extend test_flow_dissector to cover link creation
Extend the existing flow_dissector test case to run tests once using direct
prog attachments, and then for the second time using indirect attachment
via link.
The intention is to exercises the newly added high-level API for attaching
programs to network namespace with links (bpf_program__attach_netns).
Jakub Sitnicki [Sun, 31 May 2020 08:28:45 +0000 (10:28 +0200)]
selftests/bpf: Convert test_flow_dissector to use BPF skeleton
Switch flow dissector test setup from custom BPF object loader to BPF
skeleton to save boilerplate and prepare for testing higher-level API for
attaching flow dissector with bpf_link.
To avoid depending on program order in the BPF object when populating the
flow dissector PROG_ARRAY map, change the program section names to contain
the program index into the map. This follows the example set by tailcall
tests.
Jakub Sitnicki [Sun, 31 May 2020 08:28:44 +0000 (10:28 +0200)]
selftests/bpf, flow_dissector: Close TAP device FD after the test
test_flow_dissector leaves a TAP device after it's finished, potentially
interfering with other tests that will run after it. Fix it by closing the
TAP descriptor on cleanup.
Jakub Sitnicki [Sun, 31 May 2020 08:28:42 +0000 (10:28 +0200)]
bpftool: Support link show for netns-attached links
Make `bpf link show` aware of new link type, that is links attached to
netns. When listing netns-attached links, display netns inode number as its
identifier and link attach type.
Sample session:
# readlink /proc/self/ns/net
net:[4026532251]
# bpftool prog show
357: flow_dissector tag a04f5eef06a7f555 gpl
loaded_at 2020-05-30T16:53:51+0200 uid 0
xlated 16B jited 37B memlock 4096B
358: flow_dissector tag a04f5eef06a7f555 gpl
loaded_at 2020-05-30T16:53:51+0200 uid 0
xlated 16B jited 37B memlock 4096B
# bpftool link show
108: netns prog 357
netns_ino 4026532251 attach_type flow_dissector
# bpftool link -jp show
[{
"id": 108,
"type": "netns",
"prog_id": 357,
"netns_ino": 4026532251,
"attach_type": "flow_dissector"
}
]
(... after netns is gone ...)
# bpftool link show
108: netns prog 357
netns_ino 0 attach_type flow_dissector
# bpftool link -jp show
[{
"id": 108,
"type": "netns",
"prog_id": 357,
"netns_ino": 0,
"attach_type": "flow_dissector"
}
]
Jakub Sitnicki [Sun, 31 May 2020 08:28:41 +0000 (10:28 +0200)]
bpftool: Extract helpers for showing link attach type
Code for printing link attach_type is duplicated in a couple of places, and
likely will be duplicated for future link types as well. Create helpers to
prevent duplication.
Jakub Sitnicki [Sun, 31 May 2020 08:28:40 +0000 (10:28 +0200)]
libbpf: Add support for bpf_link-based netns attachment
Add bpf_program__attach_nets(), which uses LINK_CREATE subcommand to create
an FD-based kernel bpf_link, for attach types tied to network namespace,
that is BPF_FLOW_DISSECTOR for the moment.
Jakub Sitnicki [Sun, 31 May 2020 08:28:39 +0000 (10:28 +0200)]
bpf, cgroup: Return ENOLINK for auto-detached links on update
Failure to update a bpf_link because it has been auto-detached by a dying
cgroup currently results in EINVAL error, even though the arguments passed
to bpf() syscall are not wrong.
bpf_links attaching to netns in this case will return ENOLINK, which
carries the message that the link is no longer attached to anything.
Change cgroup bpf_links to do the same to keep the uAPI errors consistent.
Fixes: 0c991ebc8c69 ("bpf: Implement bpf_prog replacement for an active bpf_cgroup_link") Suggested-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200531082846.2117903-6-jakub@cloudflare.com
Jakub Sitnicki [Sun, 31 May 2020 08:28:38 +0000 (10:28 +0200)]
bpf: Add link-based BPF program attachment to network namespace
Extend bpf() syscall subcommands that operate on bpf_link, that is
LINK_CREATE, LINK_UPDATE, OBJ_GET_INFO, to accept attach types tied to
network namespaces (only flow dissector at the moment).
Link-based and prog-based attachment can be used interchangeably, but only
one can exist at a time. Attempts to attach a link when a prog is already
attached directly, and the other way around, will be met with -EEXIST.
Attempts to detach a program when link exists result in -EINVAL.
Attachment of multiple links of same attach type to one netns is not
supported with the intention to lift the restriction when a use-case
presents itself. Because of that link create returns -E2BIG when trying to
create another netns link, when one already exists.
Link-based attachments to netns don't keep a netns alive by holding a ref
to it. Instead links get auto-detached from netns when the latter is being
destroyed, using a pernet pre_exit callback.
When auto-detached, link lives in defunct state as long there are open FDs
for it. -ENOLINK is returned if a user tries to update a defunct link.
Because bpf_link to netns doesn't hold a ref to struct net, special care is
taken when releasing, updating, or filling link info. The netns might be
getting torn down when any of these link operations are in progress. That
is why auto-detach and update/release/fill_info are synchronized by the
same mutex. Also, link ops have to always check if auto-detach has not
happened yet and if netns is still alive (refcnt > 0).
Jakub Sitnicki [Sun, 31 May 2020 08:28:37 +0000 (10:28 +0200)]
flow_dissector: Move out netns_bpf prog callbacks
Move functions to manage BPF programs attached to netns that are not
specific to flow dissector to a dedicated module named
bpf/net_namespace.c.
The set of functions will grow with the addition of bpf_link support for
netns attached programs. This patch prepares ground by creating a place
for it.
This is a code move with no functional changes intended.
Jakub Sitnicki [Sun, 31 May 2020 08:28:36 +0000 (10:28 +0200)]
net: Introduce netns_bpf for BPF programs attached to netns
In order to:
(1) attach more than one BPF program type to netns, or
(2) support attaching BPF programs to netns with bpf_link, or
(3) support multi-prog attach points for netns
we will need to keep more state per netns than a single pointer like we
have now for BPF flow dissector program.
Prepare for the above by extracting netns_bpf that is part of struct net,
for storing all state related to BPF programs attached to netns.
Turn flow dissector callbacks for querying/attaching/detaching a program
into generic ones that operate on netns_bpf. Next patch will move the
generic callbacks into their own module.
This is similar to how it is organized for cgroup with cgroup_bpf.
Jakub Sitnicki [Sun, 31 May 2020 08:28:35 +0000 (10:28 +0200)]
flow_dissector: Pull locking up from prog attach callback
Split out the part of attach callback that happens with attach/detach lock
acquired. This structures the prog attach callback in a way that opens up
doors for moving the locking out of flow_dissector and into generic
callbacks for attaching/detaching progs to netns in subsequent patches.
Andrii Nakryiko [Mon, 1 Jun 2020 20:26:01 +0000 (13:26 -0700)]
libbpf: Add _GNU_SOURCE for reallocarray to ringbuf.c
On systems with recent enough glibc, reallocarray compat won't kick in, so
reallocarray() itself has to come from stdlib.h include. But _GNU_SOURCE is
necessary to enable it. So add it.
Fixes: bf99c936f947 ("libbpf: Add BPF ring buffer support") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200601202601.2139477-1-andriin@fb.com
Jiri Olsa [Sun, 31 May 2020 15:42:55 +0000 (17:42 +0200)]
bpf: Use tracing helpers for lsm programs
Currenty lsm uses bpf_tracing_func_proto helpers which do
not include stack trace or perf event output. It's useful
to have those for bpftrace lsm support [1].
Using tracing_prog_func_proto helpers for lsm programs.
Introduce xdp_convert_frame_to_buff utility routine to initialize xdp_buff
fields from xdp_frames ones. Rely on xdp_convert_frame_to_buff in veth xdp
code.
====================
This option makes it possible to programatically bind sockets
to netdevices. With the help of this option sockets
of VRF unaware applications could be distributed between
multiple VRFs with an eBPF program. This lets the applications
benefit from multiple possible routes.
v2:
- splitting up the patch to three parts
- lock_sk parameter for optional locking in sock_bindtoindex - Stanislav Fomichev
- testing the SO_BINDTODEVICE option - Andrii Nakryiko
====================
Ferenc Fejes [Sat, 30 May 2020 21:09:02 +0000 (23:09 +0200)]
selftests/bpf: Add test for SO_BINDTODEVICE opt of bpf_setsockopt
This test intended to verify if SO_BINDTODEVICE option works in
bpf_setsockopt. Because we already in the SOL_SOCKET level in this
connect bpf prog its safe to verify the sanity in the beginning of
the connect_v4_prog by calling the bind_to_device test helper.
The testing environment already created by the test_sock_addr.sh
script so this test assume that two netdevices already existing in
the system: veth pair with names test_sock_addr1 and test_sock_addr2.
The test will try to bind the socket to those devices first.
Then the test assume there are no netdevice with "nonexistent_dev"
name so the bpf_setsockopt will give use ENODEV error.
At the end the test remove the device binding from the socket
by binding it to an empty name.
Ferenc Fejes [Sat, 30 May 2020 21:09:01 +0000 (23:09 +0200)]
bpf: Allow SO_BINDTODEVICE opt in bpf_setsockopt
Extending the supported sockopts in bpf_setsockopt with
SO_BINDTODEVICE. We call sock_bindtoindex with parameter
lock_sk = false in this context because we already owning
the socket.
Ferenc Fejes [Sat, 30 May 2020 21:09:00 +0000 (23:09 +0200)]
net: Make locking in sock_bindtoindex optional
The sock_bindtoindex intended for kernel wide usage however
it will lock the socket regardless of the context. This modification
relax this behavior optionally: locking the socket will be optional
by calling the sock_bindtoindex with lock_sk = true.
The modification applied to all users of the sock_bindtoindex.
====================
If a socket is running a BPF_SK_SKB_SREAM_VERDICT program and KTLS is
enabled the data stream may be broken if both TLS stream parser and
BPF stream parser try to handle data. Fix this here by making KTLS
stream parser run first to ensure TLS messages are received correctly
and then calling the verdict program. This analogous to how we handle
a similar conflict on the TX side.
Note, this is a fix but it doesn't make sense to push this late to
bpf tree so targeting bpf-next and keeping fixes tags.
====================
John Fastabend [Fri, 29 May 2020 23:07:19 +0000 (16:07 -0700)]
bpf, selftests: Add test for ktls with skb bpf ingress policy
This adds a test for bpf ingress policy. To ensure data writes happen
as expected with extra TLS headers we run these tests with data
verification enabled by default. This will test receive packets have
"PASS" stamped into the front of the payload.
====================
Implementation of Daniel's proposal for allowing DEVMAP entries to be
a device index, program fd pair.
Programs are run after XDP_REDIRECT and have access to both Rx device
and Tx device.
v4
- moved struct bpf_devmap_val from uapi to devmap.c, named the union
and dropped the prefix from the elements - Jesper
- fixed 2 bugs in selftests
v3
- renamed struct to bpf_devmap_val
- used offsetofend to check for expected map size, modification of
Toke's comment
- check for explicit value sizes
- adjusted switch statement in dev_map_run_prog per Andrii's comment
- changed SEC shortcut to xdp_devmap
- changed selftests to use skeleton and new map declaration
v2
- moved dev_map_ext_val definition to uapi to formalize the API for devmap
extensions; add bpf_ prefix to the prog_fd and prog_id entries
- changed devmap code to handle struct in a way that it can support future
extensions
- fixed subject in libbpf patch
v1
- fixed prog put on invalid program - Toke
- changed write value from id to fd per Toke's comments about capabilities
- add test cases
====================
John Fastabend [Fri, 29 May 2020 23:06:59 +0000 (16:06 -0700)]
bpf: Fix running sk_skb program types with ktls
KTLS uses a stream parser to collect TLS messages and send them to
the upper layer tls receive handler. This ensures the tls receiver
has a full TLS header to parse when it is run. However, when a
socket has BPF_SK_SKB_STREAM_VERDICT program attached before KTLS
is enabled we end up with two stream parsers running on the same
socket.
The result is both try to run on the same socket. First the KTLS
stream parser runs and calls read_sock() which will tcp_read_sock
which in turn calls tcp_rcv_skb(). This dequeues the skb from the
sk_receive_queue. When this is done KTLS code then data_ready()
callback which because we stacked KTLS on top of the bpf stream
verdict program has been replaced with sk_psock_start_strp(). This
will in turn kick the stream parser again and eventually do the
same thing KTLS did above calling into tcp_rcv_skb() and dequeuing
a skb from the sk_receive_queue.
At this point the data stream is broke. Part of the stream was
handled by the KTLS side some other bytes may have been handled
by the BPF side. Generally this results in either missing data
or more likely a "Bad Message" complaint from the kTLS receive
handler as the BPF program steals some bytes meant to be in a
TLS header and/or the TLS header length is no longer correct.
We've already broke the idealized model where we can stack ULPs
in any order with generic callbacks on the TX side to handle this.
So in this patch we do the same thing but for RX side. We add
a sk_psock_strp_enabled() helper so TLS can learn a BPF verdict
program is running and add a tls_sw_has_ctx_rx() helper so BPF
side can learn there is a TLS ULP on the socket.
Then on BPF side we omit calling our stream parser to avoid
breaking the data stream for the KTLS receiver. Then on the
KTLS side we call BPF_SK_SKB_STREAM_VERDICT once the KTLS
receiver is done with the packet but before it posts the
msg to userspace. This gives us symmetry between the TX and
RX halfs and IMO makes it usable again. On the TX side we
process packets in this order BPF -> TLS -> TCP and on
the receive side in the reverse order TCP -> TLS -> BPF.
Discovered while testing OpenSSL 3.0 Alpha2.0 release.
David Ahern [Fri, 29 May 2020 22:07:16 +0000 (16:07 -0600)]
selftest: Add tests for XDP programs in devmap entries
Add tests to verify ability to add an XDP program to a
entry in a DEVMAP.
Add negative tests to show DEVMAP programs can not be
attached to devices as a normal XDP program, and accesses
to egress_ifindex require BPF_XDP_DEVMAP attach type.
John Fastabend [Fri, 29 May 2020 23:06:41 +0000 (16:06 -0700)]
bpf: Refactor sockmap redirect code so its easy to reuse
We will need this block of code called from tls context shortly
lets refactor the redirect logic so its easy to use. This also
cleans up the switch stmt so we have fewer fallthrough cases.
No logic changes are intended.
Fixes: d829e9c4112b5 ("tls: convert to generic sk_msg interface") Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/159079360110.5745.7024009076049029819.stgit@john-Precision-5820-Tower Signed-off-by: Alexei Starovoitov <ast@kernel.org>
David Ahern [Fri, 29 May 2020 22:07:14 +0000 (16:07 -0600)]
xdp: Add xdp_txq_info to xdp_buff
Add xdp_txq_info as the Tx counterpart to xdp_rxq_info. At the
moment only the device is added. Other fields (queue_index)
can be added as use cases arise.
>From a UAPI perspective, add egress_ifindex to xdp context for
bpf programs to see the Tx device.
Update the verifier to only allow accesses to egress_ifindex by
XDP programs with BPF_XDP_DEVMAP expected attach type.
David Ahern [Fri, 29 May 2020 22:07:13 +0000 (16:07 -0600)]
bpf: Add support to attach bpf program to a devmap entry
Add BPF_XDP_DEVMAP attach type for use with programs associated with a
DEVMAP entry.
Allow DEVMAPs to associate a program with a device entry by adding
a bpf_prog.fd to 'struct bpf_devmap_val'. Values read show the program
id, so the fd and id are a union. bpf programs can get access to the
struct via vmlinux.h.
The program associated with the fd must have type XDP with expected
attach type BPF_XDP_DEVMAP. When a program is associated with a device
index, the program is run on an XDP_REDIRECT and before the buffer is
added to the per-cpu queue. At this point rxq data is still valid; the
next patch adds tx device information allowing the prorgam to see both
ingress and egress device indices.
XDP generic is skb based and XDP programs do not work with skb's. Block
the use case by walking maps used by a program that is to be attached
via xdpgeneric and fail if any of them are DEVMAP / DEVMAP_HASH with
Block attach of BPF_XDP_DEVMAP programs to devices.
Yonghong Song [Fri, 29 May 2020 00:48:10 +0000 (17:48 -0700)]
bpf: Use strncpy_from_unsafe_strict() in bpf_seq_printf() helper
In bpf_seq_printf() helper, when user specified a "%s" in the
format string, strncpy_from_unsafe() is used to read the actual string
to a buffer. The string could be a format string or a string in
the kernel data structure. It is really unlikely that the string
will reside in the user memory.
This is different from Commit b2a5212fb634 ("bpf: Restrict bpf_trace_printk()'s %s
usage and add %pks, %pus specifier") which still used
strncpy_from_unsafe() for "%s" to preserve the old behavior.
If in the future, bpf_seq_printf() indeed needs to read user
memory, we can implement "%pus" format string.
Based on discussion in [1], if the intent is to read kernel memory,
strncpy_from_unsafe_strict() should be used. So this patch
changed to use strncpy_from_unsafe_strict().
Amritha Nambiar [Wed, 27 May 2020 00:34:36 +0000 (17:34 -0700)]
bpf: Add rx_queue_mapping to bpf_sock
Add "rx_queue_mapping" to bpf_sock. This gives read access for the
existing field (sk_rx_queue_mapping) of struct sock from bpf_sock.
Semantics for the bpf_sock rx_queue_mapping access are similar to
sk_rx_queue_get(), i.e the value NO_QUEUE_MAPPING is not allowed
and -1 is returned in that case. This is useful for transmit queue
selection based on the received queue index which is cached in the
socket in the receive path.
v3: Addressed review comments to add usecase in patch description,
and fixed default value for rx_queue_mapping.
v2: fixed build error for CONFIG_XPS wrapping, reported by
kbuild test robot <lkp@intel.com>
Daniel Borkmann [Fri, 29 May 2020 15:11:09 +0000 (17:11 +0200)]
Merge branch 'bpf-ring-buffer'
Andrii Nakryiko says:
====================
Implement a new BPF ring buffer, as presented at BPF virtual conference ([0]).
It presents an alternative to perf buffer, following its semantics closely,
but allowing sharing same instance of ring buffer across multiple CPUs
efficiently.
Most patches have extensive commentary explaining various aspects, so I'll
keep cover letter short. Overall structure of the patch set:
- patch #1 adds BPF ring buffer implementation to kernel and necessary
verifier support;
- patch #2 adds libbpf consumer implementation for BPF ringbuf;
- patch #3 adds selftest, both for single BPF ring buf use case, as well as
using it with array/hash of maps;
- patch #4 adds extensive benchmarks and provide some analysis in commit
message, it builds upon selftests/bpf's bench runner.
- patch #5 adds most of patch #1 commit message as a doc under
Documentation/bpf/ringbuf.rst.
Litmus tests, validating consumer/producer protocols and memory orderings,
were moved out as discussed in [1] and are going to be posted against -rcu
tree and put under Documentation/litmus-tests/bpf-rb.
v3->v4:
- fix ringbuf freeing (vunmap, __free_page); verified with a trivial loop
creating and closing ringbuf map endlessly (Daniel);
v2->v3:
- dropped unnecessary smp_wmb() (Paul);
- verifier reference type enhancement patch was dropped (Alexei);
- better verifier message for various memory access checks (Alexei);
- clarified a bit roundup_len() bit shifting (Alexei);
- converted doc to .rst (Alexei);
- fixed warning on 32-bit arches regarding tautological ring area size check.
v1->v2:
- commit()/discard()/output() accept flags (NO_WAKEUP/FORCE_WAKEUP) (Stanislav);
- bpf_ringbuf_query() added, returning available data size, ringbuf size,
consumer/producer positions, needed to implement smarter notification policy
(Stanislav);
- added ringbuf UAPI constants to include/uapi/linux/bpf.h (Jonathan);
- fixed sample size check, added proper ringbuf size check (Jonathan, Alexei);
- wake_up_all() is done through irq_work (Alexei);
- consistent use of smp_load_acquire/smp_store_release, no
READ_ONCE/WRITE_ONCE (Alexei);
- added Documentation/bpf/ringbuf.txt (Stanislav);
- updated litmus test with smp_load_acquire/smp_store_release changes;
- added ring_buffer__consume() API to libbpf for busy-polling;
- ring_buffer__poll() on success returns number of records consumed;
- fixed EPOLL notifications, don't assume available data, done similarly to
perfbuf's implementation;
- both ringbuf and perfbuf now have --rb-sampled mode, instead of
pb-raw/pb-custom mode, updated benchmark results;
- extended ringbuf selftests to validate epoll logic/manual notification
logic, as well as bpf_ringbuf_query().
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Anton Protopopov [Wed, 27 May 2020 18:57:00 +0000 (18:57 +0000)]
selftests/bpf: Add tests for write-only stacks/queues
For write-only stacks and queues bpf_map_update_elem should be allowed, but
bpf_map_lookup_elem and bpf_map_lookup_and_delete_elem should fail with EPERM.
Andrii Nakryiko [Fri, 29 May 2020 07:54:24 +0000 (00:54 -0700)]
docs/bpf: Add BPF ring buffer design notes
Add commit description from patch #1 as a stand-alone documentation under
Documentation/bpf, as it might be more convenient format, in long term
perspective.
Suggested-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200529075424.3139988-6-andriin@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Andrii Nakryiko [Fri, 29 May 2020 07:54:23 +0000 (00:54 -0700)]
bpf: Add BPF ringbuf and perf buffer benchmarks
Extend bench framework with ability to have benchmark-provided child argument
parser for custom benchmark-specific parameters. This makes bench generic code
modular and independent from any specific benchmark.
Also implement a set of benchmarks for new BPF ring buffer and existing perf
buffer. 4 benchmarks were implemented: 2 variations for each of BPF ringbuf
and perfbuf:,
- rb-libbpf utilizes stock libbpf ring_buffer manager for reading data;
- rb-custom implements custom ring buffer setup and reading code, to
eliminate overheads inherent in generic libbpf code due to callback
functions and the need to update consumer position after each consumed
record, instead of batching updates (due to pessimistic assumption that
user callback might take long time and thus could unnecessarily hold ring
buffer space for too long);
- pb-libbpf uses stock libbpf perf_buffer code with all the default
settings, though uses higher-performance raw event callback to minimize
unnecessary overhead;
- pb-custom implements its own custom consumer code to minimize any possible
overhead of generic libbpf implementation and indirect function calls.
All of the test support default, no data notification skipped, mode, as well
as sampled mode (with --rb-sampled flag), which allows to trigger epoll
notification less frequently and reduce overhead. As will be shown, this mode
is especially critical for perf buffer, which suffers from high overhead of
wakeups in kernel.
Otherwise, all benchamrks implement similar way to generate a batch of records
by using fentry/sys_getpgid BPF program, which pushes a bunch of records in
a tight loop and records number of successful and dropped samples. Each record
is a small 8-byte integer, to minimize the effect of memory copying with
bpf_perf_event_output() and bpf_ringbuf_output().
Benchmarks that have only one producer implement optional back-to-back mode,
in which record production and consumption is alternating on the same CPU.
This is the highest-throughput happy case, showing ultimate performance
achievable with either BPF ringbuf or perfbuf.
All the below scenarios are implemented in a script in
benchs/run_bench_ringbufs.sh. Tests were performed on 28-core/56-thread
Intel Xeon CPU E5-2680 v4 @ 2.40GHz CPU.
Single producer on one CPU, consumer on another one, both running at full
speed. Curiously, rb-libbpf has higher throughput than objectively faster (due
to more lightweight consumer code path) rb-custom. It appears that faster
consumer causes kernel to send notifications more frequently, because consumer
appears to be caught up more frequently. Performance of perfbuf suffers from
default "no sampling" policy and huge overhead that causes.
In sampled mode, rb-custom is winning very significantly eliminating too
frequent in-kernel wakeups, the gain appears to be more than 2x.
Perf buffer achieves even more impressive wins, compared to stock perfbuf
settings, with 10x improvements in throughput with 1:500 sampling rate. The
trade-off is that with sampling, application might not get next X events until
X+1st arrives, which is not always acceptable. With steady influx of events,
though, this shouldn't be a problem.
Overall, single-producer performance of ring buffers seems to be better no
matter the sampled/non-sampled modes, but it especially beats ring buffer
without sampling due to its adaptive notification approach.
Here we test a back-to-back mode, which is arguably best-case scenario both
for BPF ringbuf and perfbuf, because there is no contention and for ringbuf
also no excessive notification, because consumer appears to be behind after
the first record. For ringbuf, custom consumer code clearly wins with 21.5 vs
16 million records per second exchanged between producer and consumer. Sampled
mode actually hurts a bit due to slightly slower producer logic (it needs to
fetch amount of data available to decide whether to skip or force notification).
Perfbuf with wakeup sampling gets 5.5x throughput increase, compared to
no-sampling version. There also doesn't seem to be noticeable overhead from
generic libbpf handling code.
This benchmark shows the effect of event sampling for perfbuf. Back-to-back
mode for highest throughput. Just doing every 5th record notification gives
3.5x speed up. 250-500 appears to be the point of diminishing return, with
almost 9x speed up. Most benchmarks use 500 as the default sampling for pb-raw
and pb-custom.
Similar benchmark for ring buffer also shows a great advantage (in terms of
throughput) of skipping notifications. Skipping every 5th one gives 4x boost.
Also similar to perfbuf case, 250-500 seems to be the point of diminishing
returns, giving roughly 20x better results.
Keep in mind, for this test, notifications are controlled manually with
BPF_RB_NO_WAKEUP and BPF_RB_FORCE_WAKEUP. As can be seen from previous
benchmarks, adaptive notifications based on consumer's positions provides same
(or even slightly better due to simpler load generator on BPF side) benefits in
favorable back-to-back scenario. Over zealous and fast consumer, which is
almost always caught up, will make thoughput numbers smaller. That's the case
when manual notification control might prove to be extremely beneficial.
BPF ringbuf supports two sets of APIs with various usability and performance
tradeoffs: bpf_ringbuf_reserve()+bpf_ringbuf_commit() vs bpf_ringbuf_output().
This benchmark clearly shows superiority of reserve+commit approach, despite
using a small 8-byte record size.
This benchmark shows one of the worst-case scenarios, in which producer and
consumer do not coordinate *and* fight for the same CPU. No batch count and
sampling settings were able to eliminate drops for ringbuffer, producer is
just too fast for consumer to keep up. But ringbuf and perfbuf still able to
pass through quite a lot of messages, which is more than enough for a lot of
applications.
Ringbuf uses a very short-duration spinlock during reservation phase, to check
few invariants, increment producer count and set record header. This is the
biggest point of contention for ringbuf implementation. This benchmark
evaluates the effect of multiple competing writers on overall throughput of
a single shared ringbuffer.
Overall throughput drops almost 2x when going from single to two
highly-contended producers, gradually dropping with additional competing
producers. Performance drop stabilizes at around 20 producers and hovers
around 2mln even with 50+ fighting producers, which is a 5x drop compared to
non-contended case. Good kernel implementation in kernel helps maintain decent
performance here.
Note, that in the intended real-world scenarios, it's not expected to get even
close to such a high levels of contention. But if contention will become
a problem, there is always an option of sharding few ring buffers across a set
of CPUs.
Andrii Nakryiko [Fri, 29 May 2020 07:54:22 +0000 (00:54 -0700)]
selftests/bpf: Add BPF ringbuf selftests
Both singleton BPF ringbuf and BPF ringbuf with map-in-map use cases are tested.
Also reserve+submit/discards and output variants of API are validated.
Andrii Nakryiko [Fri, 29 May 2020 07:54:21 +0000 (00:54 -0700)]
libbpf: Add BPF ring buffer support
Declaring and instantiating BPF ring buffer doesn't require any changes to
libbpf, as it's just another type of maps. So using existing BTF-defined maps
syntax with __uint(type, BPF_MAP_TYPE_RINGBUF) and __uint(max_elements,
<size-of-ring-buf>) is all that's necessary to create and use BPF ring buffer.
This patch adds BPF ring buffer consumer to libbpf. It is very similar to
perf_buffer implementation in terms of API, but also attempts to fix some
minor problems and inconveniences with existing perf_buffer API.
ring_buffer support both single ring buffer use case (with just using
ring_buffer__new()), as well as allows to add more ring buffers, each with its
own callback and context. This allows to efficiently poll and consume
multiple, potentially completely independent, ring buffers, using single
epoll instance.
The latter is actually a problem in practice for applications
that are using multiple sets of perf buffers. They have to create multiple
instances for struct perf_buffer and poll them independently or in a loop,
each approach having its own problems (e.g., inability to use a common poll
timeout). struct ring_buffer eliminates this problem by aggregating many
independent ring buffer instances under the single "ring buffer manager".
Second, perf_buffer's callback can't return error, so applications that need
to stop polling due to error in data or data signalling the end, have to use
extra mechanisms to signal that polling has to stop. ring_buffer's callback
can return error, which will be passed through back to user code and can be
acted upon appropariately.
Two APIs allow to consume ring buffer data:
- ring_buffer__poll(), which will wait for data availability notification
and will consume data only from reported ring buffer(s); this API allows
to efficiently use resources by reading data only when it becomes
available;
- ring_buffer__consume(), will attempt to read new records regardless of
data availablity notification sub-system. This API is useful for cases
when lowest latency is required, in expense of burning CPU resources.
Andrii Nakryiko [Fri, 29 May 2020 07:54:20 +0000 (00:54 -0700)]
bpf: Implement BPF ring buffer and verifier support for it
This commit adds a new MPSC ring buffer implementation into BPF ecosystem,
which allows multiple CPUs to submit data to a single shared ring buffer. On
the consumption side, only single consumer is assumed.
Motivation
----------
There are two distinctive motivators for this work, which are not satisfied by
existing perf buffer, which prompted creation of a new ring buffer
implementation.
- more efficient memory utilization by sharing ring buffer across CPUs;
- preserving ordering of events that happen sequentially in time, even
across multiple CPUs (e.g., fork/exec/exit events for a task).
These two problems are independent, but perf buffer fails to satisfy both.
Both are a result of a choice to have per-CPU perf ring buffer. Both can be
also solved by having an MPSC implementation of ring buffer. The ordering
problem could technically be solved for perf buffer with some in-kernel
counting, but given the first one requires an MPSC buffer, the same solution
would solve the second problem automatically.
Semantics and APIs
------------------
Single ring buffer is presented to BPF programs as an instance of BPF map of
type BPF_MAP_TYPE_RINGBUF. Two other alternatives considered, but ultimately
rejected.
One way would be to, similar to BPF_MAP_TYPE_PERF_EVENT_ARRAY, make
BPF_MAP_TYPE_RINGBUF could represent an array of ring buffers, but not enforce
"same CPU only" rule. This would be more familiar interface compatible with
existing perf buffer use in BPF, but would fail if application needed more
advanced logic to lookup ring buffer by arbitrary key. HASH_OF_MAPS addresses
this with current approach. Additionally, given the performance of BPF
ringbuf, many use cases would just opt into a simple single ring buffer shared
among all CPUs, for which current approach would be an overkill.
Another approach could introduce a new concept, alongside BPF map, to
represent generic "container" object, which doesn't necessarily have key/value
interface with lookup/update/delete operations. This approach would add a lot
of extra infrastructure that has to be built for observability and verifier
support. It would also add another concept that BPF developers would have to
familiarize themselves with, new syntax in libbpf, etc. But then would really
provide no additional benefits over the approach of using a map.
BPF_MAP_TYPE_RINGBUF doesn't support lookup/update/delete operations, but so
doesn't few other map types (e.g., queue and stack; array doesn't support
delete, etc).
The approach chosen has an advantage of re-using existing BPF map
infrastructure (introspection APIs in kernel, libbpf support, etc), being
familiar concept (no need to teach users a new type of object in BPF program),
and utilizing existing tooling (bpftool). For common scenario of using
a single ring buffer for all CPUs, it's as simple and straightforward, as
would be with a dedicated "container" object. On the other hand, by being
a map, it can be combined with ARRAY_OF_MAPS and HASH_OF_MAPS map-in-maps to
implement a wide variety of topologies, from one ring buffer for each CPU
(e.g., as a replacement for perf buffer use cases), to a complicated
application hashing/sharding of ring buffers (e.g., having a small pool of
ring buffers with hashed task's tgid being a look up key to preserve order,
but reduce contention).
Key and value sizes are enforced to be zero. max_entries is used to specify
the size of ring buffer and has to be a power of 2 value.
There are a bunch of similarities between perf buffer
(BPF_MAP_TYPE_PERF_EVENT_ARRAY) and new BPF ring buffer semantics:
- variable-length records;
- if there is no more space left in ring buffer, reservation fails, no
blocking;
- memory-mappable data area for user-space applications for ease of
consumption and high performance;
- epoll notifications for new incoming data;
- but still the ability to do busy polling for new data to achieve the
lowest latency, if necessary.
BPF ringbuf provides two sets of APIs to BPF programs:
- bpf_ringbuf_output() allows to *copy* data from one place to a ring
buffer, similarly to bpf_perf_event_output();
- bpf_ringbuf_reserve()/bpf_ringbuf_commit()/bpf_ringbuf_discard() APIs
split the whole process into two steps. First, a fixed amount of space is
reserved. If successful, a pointer to a data inside ring buffer data area
is returned, which BPF programs can use similarly to a data inside
array/hash maps. Once ready, this piece of memory is either committed or
discarded. Discard is similar to commit, but makes consumer ignore the
record.
bpf_ringbuf_output() has disadvantage of incurring extra memory copy, because
record has to be prepared in some other place first. But it allows to submit
records of the length that's not known to verifier beforehand. It also closely
matches bpf_perf_event_output(), so will simplify migration significantly.
bpf_ringbuf_reserve() avoids the extra copy of memory by providing a memory
pointer directly to ring buffer memory. In a lot of cases records are larger
than BPF stack space allows, so many programs have use extra per-CPU array as
a temporary heap for preparing sample. bpf_ringbuf_reserve() avoid this needs
completely. But in exchange, it only allows a known constant size of memory to
be reserved, such that verifier can verify that BPF program can't access
memory outside its reserved record space. bpf_ringbuf_output(), while slightly
slower due to extra memory copy, covers some use cases that are not suitable
for bpf_ringbuf_reserve().
The difference between commit and discard is very small. Discard just marks
a record as discarded, and such records are supposed to be ignored by consumer
code. Discard is useful for some advanced use-cases, such as ensuring
all-or-nothing multi-record submission, or emulating temporary malloc()/free()
within single BPF program invocation.
Each reserved record is tracked by verifier through existing
reference-tracking logic, similar to socket ref-tracking. It is thus
impossible to reserve a record, but forget to submit (or discard) it.
bpf_ringbuf_query() helper allows to query various properties of ring buffer.
Currently 4 are supported:
- BPF_RB_AVAIL_DATA returns amount of unconsumed data in ring buffer;
- BPF_RB_RING_SIZE returns the size of ring buffer;
- BPF_RB_CONS_POS/BPF_RB_PROD_POS returns current logical possition of
consumer/producer, respectively.
Returned values are momentarily snapshots of ring buffer state and could be
off by the time helper returns, so this should be used only for
debugging/reporting reasons or for implementing various heuristics, that take
into account highly-changeable nature of some of those characteristics.
One such heuristic might involve more fine-grained control over poll/epoll
notifications about new data availability in ring buffer. Together with
BPF_RB_NO_WAKEUP/BPF_RB_FORCE_WAKEUP flags for output/commit/discard helpers,
it allows BPF program a high degree of control and, e.g., more efficient
batched notifications. Default self-balancing strategy, though, should be
adequate for most applications and will work reliable and efficiently already.
Design and implementation
-------------------------
This reserve/commit schema allows a natural way for multiple producers, either
on different CPUs or even on the same CPU/in the same BPF program, to reserve
independent records and work with them without blocking other producers. This
means that if BPF program was interruped by another BPF program sharing the
same ring buffer, they will both get a record reserved (provided there is
enough space left) and can work with it and submit it independently. This
applies to NMI context as well, except that due to using a spinlock during
reservation, in NMI context, bpf_ringbuf_reserve() might fail to get a lock,
in which case reservation will fail even if ring buffer is not full.
The ring buffer itself internally is implemented as a power-of-2 sized
circular buffer, with two logical and ever-increasing counters (which might
wrap around on 32-bit architectures, that's not a problem):
- consumer counter shows up to which logical position consumer consumed the
data;
- producer counter denotes amount of data reserved by all producers.
Each time a record is reserved, producer that "owns" the record will
successfully advance producer counter. At that point, data is still not yet
ready to be consumed, though. Each record has 8 byte header, which contains
the length of reserved record, as well as two extra bits: busy bit to denote
that record is still being worked on, and discard bit, which might be set at
commit time if record is discarded. In the latter case, consumer is supposed
to skip the record and move on to the next one. Record header also encodes
record's relative offset from the beginning of ring buffer data area (in
pages). This allows bpf_ringbuf_commit()/bpf_ringbuf_discard() to accept only
the pointer to the record itself, without requiring also the pointer to ring
buffer itself. Ring buffer memory location will be restored from record
metadata header. This significantly simplifies verifier, as well as improving
API usability.
Producer counter increments are serialized under spinlock, so there is
a strict ordering between reservations. Commits, on the other hand, are
completely lockless and independent. All records become available to consumer
in the order of reservations, but only after all previous records where
already committed. It is thus possible for slow producers to temporarily hold
off submitted records, that were reserved later.
Reservation/commit/consumer protocol is verified by litmus tests in
Documentation/litmus-test/bpf-rb.
One interesting implementation bit, that significantly simplifies (and thus
speeds up as well) implementation of both producers and consumers is how data
area is mapped twice contiguously back-to-back in the virtual memory. This
allows to not take any special measures for samples that have to wrap around
at the end of the circular buffer data area, because the next page after the
last data page would be first data page again, and thus the sample will still
appear completely contiguous in virtual memory. See comment and a simple ASCII
diagram showing this visually in bpf_ringbuf_area_alloc().
Another feature that distinguishes BPF ringbuf from perf ring buffer is
a self-pacing notifications of new data being availability.
bpf_ringbuf_commit() implementation will send a notification of new record
being available after commit only if consumer has already caught up right up
to the record being committed. If not, consumer still has to catch up and thus
will see new data anyways without needing an extra poll notification.
Benchmarks (see tools/testing/selftests/bpf/benchs/bench_ringbuf.c) show that
this allows to achieve a very high throughput without having to resort to
tricks like "notify only every Nth sample", which are necessary with perf
buffer. For extreme cases, when BPF program wants more manual control of
notifications, commit/discard/output helpers accept BPF_RB_NO_WAKEUP and
BPF_RB_FORCE_WAKEUP flags, which give full control over notifications of data
availability, but require extra caution and diligence in using this API.
Comparison to alternatives
--------------------------
Before considering implementing BPF ring buffer from scratch existing
alternatives in kernel were evaluated, but didn't seem to meet the needs. They
largely fell into few categores:
- per-CPU buffers (perf, ftrace, etc), which don't satisfy two motivations
outlined above (ordering and memory consumption);
- linked list-based implementations; while some were multi-producer designs,
consuming these from user-space would be very complicated and most
probably not performant; memory-mapping contiguous piece of memory is
simpler and more performant for user-space consumers;
- io_uring is SPSC, but also requires fixed-sized elements. Naively turning
SPSC queue into MPSC w/ lock would have subpar performance compared to
locked reserve + lockless commit, as with BPF ring buffer. Fixed sized
elements would be too limiting for BPF programs, given existing BPF
programs heavily rely on variable-sized perf buffer already;
- specialized implementations (like a new printk ring buffer, [0]) with lots
of printk-specific limitations and implications, that didn't seem to fit
well for intended use with BPF programs.
Anton Protopopov [Wed, 27 May 2020 18:56:59 +0000 (18:56 +0000)]
bpf: Fix map permissions check
The map_lookup_and_delete_elem() function should check for both FMODE_CAN_WRITE
and FMODE_CAN_READ permissions because it returns a map element to user space.
Fixes: bd513cd08f10 ("bpf: add MAP_LOOKUP_AND_DELETE_ELEM syscall") Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200527185700.14658-5-a.s.protopopov@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
John Fastabend [Sun, 24 May 2020 16:51:57 +0000 (09:51 -0700)]
bpf, selftests: Test probe_* helpers from SCHED_CLS
Lets test using probe* in SCHED_CLS network programs as well just
to be sure these keep working. Its cheap to add the extra test
and provides a second context to test outside of sk_msg after
we generalized probe* helpers to all networking types.
John Fastabend [Sun, 24 May 2020 16:51:36 +0000 (09:51 -0700)]
bpf, selftests: Add sk_msg helpers load and attach test
The test itself is not particularly useful but it encodes a common
pattern we have.
Namely do a sk storage lookup then depending on data here decide if
we need to do more work or alternatively allow packet to PASS. Then
if we need to do more work consult task_struct for more information
about the running task. Finally based on this additional information
drop or pass the data. In this case the suspicious check is not so
realisitic but it encodes the general pattern and uses the helpers
so we test the workflow.
This is a load test to ensure verifier correctly handles this case.
John Fastabend [Sun, 24 May 2020 16:50:55 +0000 (09:50 -0700)]
bpf: Extend bpf_base_func_proto helpers with probe_* and *current_task*
Often it is useful when applying policy to know something about the
task. If the administrator has CAP_SYS_ADMIN rights then they can
use kprobe + networking hook and link the two programs together to
accomplish this. However, this is a bit clunky and also means we have
to call both the network program and kprobe program when we could just
use a single program and avoid passing metadata through sk_msg/skb->cb,
socket, maps, etc.
To accomplish this add probe_* helpers to bpf_base_func_proto programs
guarded by a perfmon_capable() check. New supported helpers are the
following,
projects / mirror_ubuntu-kernels.git / log