From: Jakub Sitnicki <jakub@cloudflare.com>
To: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org, kernel-team@cloudflare.com,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Andrii Nakryiko <andrii.nakryiko@gmail.com>,
Lorenz Bauer <lmb@cloudflare.com>,
Marek Majkowski <marek@cloudflare.com>,
Stanislav Fomichev <sdf@google.com>
Subject: [PATCH bpf-next v2 00/12] Link-based program attachment to network namespaces
Date: Sun, 31 May 2020 10:28:34 +0200 [thread overview]
Message-ID: <20200531082846.2117903-1-jakub@cloudflare.com> (raw)
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.
-jkbs
[0] https://lore.kernel.org/bpf/20200511185218.1422406-1-jakub@cloudflare.com/
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Lorenz Bauer <lmb@cloudflare.com>
Cc: Marek Majkowski <marek@cloudflare.com>
Cc: Stanislav Fomichev <sdf@google.com>
v1 -> v2:
- 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 (12):
flow_dissector: Pull locking up from prog attach callback
net: Introduce netns_bpf for BPF programs attached to netns
flow_dissector: Move out netns_bpf prog callbacks
bpf: Add link-based BPF program attachment to network namespace
bpf, cgroup: Return ENOLINK for auto-detached links on update
libbpf: Add support for bpf_link-based netns attachment
bpftool: Extract helpers for showing link attach type
bpftool: Support link show for netns-attached links
selftests/bpf: Add tests for attaching bpf_link to netns
selftests/bpf, flow_dissector: Close TAP device FD after the test
selftests/bpf: Convert test_flow_dissector to use BPF skeleton
selftests/bpf: Extend test_flow_dissector to cover link creation
include/linux/bpf-netns.h | 64 ++
include/linux/bpf_types.h | 3 +
include/linux/skbuff.h | 26 -
include/net/flow_dissector.h | 6 +
include/net/net_namespace.h | 4 +-
include/net/netns/bpf.h | 18 +
include/uapi/linux/bpf.h | 5 +
kernel/bpf/Makefile | 1 +
kernel/bpf/cgroup.c | 2 +-
kernel/bpf/net_namespace.c | 373 +++++++++++
kernel/bpf/syscall.c | 10 +-
net/core/flow_dissector.c | 124 +---
tools/bpf/bpftool/link.c | 54 +-
tools/include/uapi/linux/bpf.h | 5 +
tools/lib/bpf/libbpf.c | 23 +-
tools/lib/bpf/libbpf.h | 2 +
tools/lib/bpf/libbpf.map | 1 +
.../selftests/bpf/prog_tests/flow_dissector.c | 166 +++--
.../bpf/prog_tests/flow_dissector_reattach.c | 588 ++++++++++++++++--
tools/testing/selftests/bpf/progs/bpf_flow.c | 20 +-
20 files changed, 1248 insertions(+), 247 deletions(-)
create mode 100644 include/linux/bpf-netns.h
create mode 100644 include/net/netns/bpf.h
create mode 100644 kernel/bpf/net_namespace.c
--
2.25.4
next reply other threads:[~2020-05-31 8:28 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-31 8:28 Jakub Sitnicki [this message]
2020-05-31 8:28 ` [PATCH bpf-next v2 01/12] flow_dissector: Pull locking up from prog attach callback Jakub Sitnicki
2020-05-31 8:28 ` [PATCH bpf-next v2 02/12] net: Introduce netns_bpf for BPF programs attached to netns Jakub Sitnicki
2020-05-31 8:28 ` [PATCH bpf-next v2 03/12] flow_dissector: Move out netns_bpf prog callbacks Jakub Sitnicki
2020-05-31 8:28 ` [PATCH bpf-next v2 04/12] bpf: Add link-based BPF program attachment to network namespace Jakub Sitnicki
2020-06-01 22:30 ` Andrii Nakryiko
2020-06-02 9:30 ` Jakub Sitnicki
2020-06-02 17:38 ` Andrii Nakryiko
2020-05-31 8:28 ` [PATCH bpf-next v2 05/12] bpf, cgroup: Return ENOLINK for auto-detached links on update Jakub Sitnicki
2020-06-01 22:31 ` Andrii Nakryiko
2020-05-31 8:28 ` [PATCH bpf-next v2 06/12] libbpf: Add support for bpf_link-based netns attachment Jakub Sitnicki
2020-06-01 22:32 ` Andrii Nakryiko
2020-05-31 8:28 ` [PATCH bpf-next v2 07/12] bpftool: Extract helpers for showing link attach type Jakub Sitnicki
2020-06-01 22:35 ` Andrii Nakryiko
2020-06-02 9:37 ` Jakub Sitnicki
2020-06-02 17:39 ` Andrii Nakryiko
2020-05-31 8:28 ` [PATCH bpf-next v2 08/12] bpftool: Support link show for netns-attached links Jakub Sitnicki
2020-06-01 22:38 ` Andrii Nakryiko
2020-05-31 8:28 ` [PATCH bpf-next v2 09/12] selftests/bpf: Add tests for attaching bpf_link to netns Jakub Sitnicki
2020-05-31 8:28 ` [PATCH bpf-next v2 10/12] selftests/bpf, flow_dissector: Close TAP device FD after the test Jakub Sitnicki
2020-05-31 8:28 ` [PATCH bpf-next v2 11/12] selftests/bpf: Convert test_flow_dissector to use BPF skeleton Jakub Sitnicki
2020-06-01 22:42 ` Andrii Nakryiko
2020-06-02 9:46 ` Jakub Sitnicki
2020-05-31 8:28 ` [PATCH bpf-next v2 12/12] selftests/bpf: Extend test_flow_dissector to cover link creation Jakub Sitnicki
2020-06-01 22:26 ` [PATCH bpf-next v2 00/12] Link-based program attachment to network namespaces Alexei Starovoitov
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