Cross-merge networking fixes after downstream PR.
Conflicts:
include/linux/filter.h
kernel/bpf/core.c
66e13b615a ("bpf: verifier: prevent userspace memory access")
d503a04f8b ("bpf: Add support for certain atomics in bpf_arena to x86 JIT")
https://lore.kernel.org/all/20240429114939.210328b0@canb.auug.org.au/
No adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
I added dst_rt6_info() in commit
e8dfd42c17 ("ipv6: introduce dst_rt6_info() helper")
This patch does a similar change for IPv4.
Instead of (struct rtable *)dst casts, we can use :
#define dst_rtable(_ptr) \
container_of_const(_ptr, struct rtable, dst)
Patch is smaller than IPv6 one, because IPv4 has skb_rtable() helper.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://lore.kernel.org/r/20240429133009.1227754-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
pull-request: bpf-next 2024-04-29
We've added 147 non-merge commits during the last 32 day(s) which contain
a total of 158 files changed, 9400 insertions(+), 2213 deletions(-).
The main changes are:
1) Add an internal-only BPF per-CPU instruction for resolving per-CPU
memory addresses and implement support in x86 BPF JIT. This allows
inlining per-CPU array and hashmap lookups
and the bpf_get_smp_processor_id() helper, from Andrii Nakryiko.
2) Add BPF link support for sk_msg and sk_skb programs, from Yonghong Song.
3) Optimize x86 BPF JIT's emit_mov_imm64, and add support for various
atomics in bpf_arena which can be JITed as a single x86 instruction,
from Alexei Starovoitov.
4) Add support for passing mark with bpf_fib_lookup helper,
from Anton Protopopov.
5) Add a new bpf_wq API for deferring events and refactor sleepable
bpf_timer code to keep common code where possible,
from Benjamin Tissoires.
6) Fix BPF_PROG_TEST_RUN infra with regards to bpf_dummy_struct_ops programs
to check when NULL is passed for non-NULLable parameters,
from Eduard Zingerman.
7) Harden the BPF verifier's and/or/xor value tracking,
from Harishankar Vishwanathan.
8) Introduce crypto kfuncs to make BPF programs able to utilize the kernel
crypto subsystem, from Vadim Fedorenko.
9) Various improvements to the BPF instruction set standardization doc,
from Dave Thaler.
10) Extend libbpf APIs to partially consume items from the BPF ringbuffer,
from Andrea Righi.
11) Bigger batch of BPF selftests refactoring to use common network helpers
and to drop duplicate code, from Geliang Tang.
12) Support bpf_tail_call_static() helper for BPF programs with GCC 13,
from Jose E. Marchesi.
13) Add bpf_preempt_{disable,enable}() kfuncs in order to allow a BPF
program to have code sections where preemption is disabled,
from Kumar Kartikeya Dwivedi.
14) Allow invoking BPF kfuncs from BPF_PROG_TYPE_SYSCALL programs,
from David Vernet.
15) Extend the BPF verifier to allow different input maps for a given
bpf_for_each_map_elem() helper call in a BPF program, from Philo Lu.
16) Add support for PROBE_MEM32 and bpf_addr_space_cast instructions
for riscv64 and arm64 JITs to enable BPF Arena, from Puranjay Mohan.
17) Shut up a false-positive KMSAN splat in interpreter mode by unpoison
the stack memory, from Martin KaFai Lau.
18) Improve xsk selftest coverage with new tests on maximum and minimum
hardware ring size configurations, from Tushar Vyavahare.
19) Various ReST man pages fixes as well as documentation and bash completion
improvements for bpftool, from Rameez Rehman & Quentin Monnet.
20) Fix libbpf with regards to dumping subsequent char arrays,
from Quentin Deslandes.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (147 commits)
bpf, docs: Clarify PC use in instruction-set.rst
bpf_helpers.h: Define bpf_tail_call_static when building with GCC
bpf, docs: Add introduction for use in the ISA Internet Draft
selftests/bpf: extend BPF_SOCK_OPS_RTT_CB test for srtt and mrtt_us
bpf: add mrtt and srtt as BPF_SOCK_OPS_RTT_CB args
selftests/bpf: dummy_st_ops should reject 0 for non-nullable params
bpf: check bpf_dummy_struct_ops program params for test runs
selftests/bpf: do not pass NULL for non-nullable params in dummy_st_ops
selftests/bpf: adjust dummy_st_ops_success to detect additional error
bpf: mark bpf_dummy_struct_ops.test_1 parameter as nullable
selftests/bpf: Add ring_buffer__consume_n test.
bpf: Add bpf_guard_preempt() convenience macro
selftests: bpf: crypto: add benchmark for crypto functions
selftests: bpf: crypto skcipher algo selftests
bpf: crypto: add skcipher to bpf crypto
bpf: make common crypto API for TC/XDP programs
bpf: update the comment for BTF_FIELDS_MAX
selftests/bpf: Fix wq test.
selftests/bpf: Use make_sockaddr in test_sock_addr
selftests/bpf: Use connect_to_addr in test_sock_addr
...
====================
Link: https://lore.kernel.org/r/20240429131657.19423-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Instead of (struct rt6_info *)dst casts, we can use :
#define dst_rt6_info(_ptr) \
container_of_const(_ptr, struct rt6_info, dst)
Some places needed missing const qualifiers :
ip6_confirm_neigh(), ipv6_anycast_destination(),
ipv6_unicast_destination(), has_gateway()
v2: added missing parts (David Ahern)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
When redirecting a packet using XDP, the bpf_redirect_map() helper will set
up the redirect destination information in struct bpf_redirect_info (using
the __bpf_xdp_redirect_map() helper function), and the xdp_do_redirect()
function will read this information after the XDP program returns and pass
the frame on to the right redirect destination.
When using the BPF_F_BROADCAST flag to do multicast redirect to a whole
map, __bpf_xdp_redirect_map() sets the 'map' pointer in struct
bpf_redirect_info to point to the destination map to be broadcast. And
xdp_do_redirect() reacts to the value of this map pointer to decide whether
it's dealing with a broadcast or a single-value redirect. However, if the
destination map is being destroyed before xdp_do_redirect() is called, the
map pointer will be cleared out (by bpf_clear_redirect_map()) without
waiting for any XDP programs to stop running. This causes xdp_do_redirect()
to think that the redirect was to a single target, but the target pointer
is also NULL (since broadcast redirects don't have a single target), so
this causes a crash when a NULL pointer is passed to dev_map_enqueue().
To fix this, change xdp_do_redirect() to react directly to the presence of
the BPF_F_BROADCAST flag in the 'flags' value in struct bpf_redirect_info
to disambiguate between a single-target and a broadcast redirect. And only
read the 'map' pointer if the broadcast flag is set, aborting if that has
been cleared out in the meantime. This prevents the crash, while keeping
the atomic (cmpxchg-based) clearing of the map pointer itself, and without
adding any more checks in the non-broadcast fast path.
Fixes: e624d4ed4a ("xdp: Extend xdp_redirect_map with broadcast support")
Reported-and-tested-by: syzbot+af9492708df9797198d6@syzkaller.appspotmail.com
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Link: https://lore.kernel.org/r/20240418071840.156411-1-toke@redhat.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Historically, tunnel flags like TUNNEL_CSUM or TUNNEL_ERSPAN_OPT
have been defined as __be16. Now all of those 16 bits are occupied
and there's no more free space for new flags.
It can't be simply switched to a bigger container with no
adjustments to the values, since it's an explicit Endian storage,
and on LE systems (__be16)0x0001 equals to
(__be64)0x0001000000000000.
We could probably define new 64-bit flags depending on the
Endianness, i.e. (__be64)0x0001 on BE and (__be64)0x00010000... on
LE, but that would introduce an Endianness dependency and spawn a
ton of Sparse warnings. To mitigate them, all of those places which
were adjusted with this change would be touched anyway, so why not
define stuff properly if there's no choice.
Define IP_TUNNEL_*_BIT counterparts as a bit number instead of the
value already coded and a fistful of <16 <-> bitmap> converters and
helpers. The two flags which have a different bit position are
SIT_ISATAP_BIT and VTI_ISVTI_BIT, as they were defined not as
__cpu_to_be16(), but as (__force __be16), i.e. had different
positions on LE and BE. Now they both have strongly defined places.
Change all __be16 fields which were used to store those flags, to
IP_TUNNEL_DECLARE_FLAGS() -> DECLARE_BITMAP(__IP_TUNNEL_FLAG_NUM) ->
unsigned long[1] for now, and replace all TUNNEL_* occurrences to
their bitmap counterparts. Use the converters in the places which talk
to the userspace, hardware (NFP) or other hosts (GRE header). The rest
must explicitly use the new flags only. This must be done at once,
otherwise there will be too many conversions throughout the code in
the intermediate commits.
Finally, disable the old __be16 flags for use in the kernel code
(except for the two 'irregular' flags mentioned above), to prevent
any accidental (mis)use of them. For the userspace, nothing is
changed, only additions were made.
Most noticeable bloat-o-meter difference (.text):
vmlinux: 307/-1 (306)
gre.ko: 62/0 (62)
ip_gre.ko: 941/-217 (724) [*]
ip_tunnel.ko: 390/-900 (-510) [**]
ip_vti.ko: 138/0 (138)
ip6_gre.ko: 534/-18 (516) [*]
ip6_tunnel.ko: 118/-10 (108)
[*] gre_flags_to_tnl_flags() grew, but still is inlined
[**] ip_tunnel_find() got uninlined, hence such decrease
The average code size increase in non-extreme case is 100-200 bytes
per module, mostly due to sizeof(long) > sizeof(__be16), as
%__IP_TUNNEL_FLAG_NUM is less than %BITS_PER_LONG and the compilers
are able to expand the majority of bitmap_*() calls here into direct
operations on scalars.
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The struct bpf_fib_lookup should not grow outside of its 64 bytes.
Add a static assert to validate this.
Suggested-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240326101742.17421-4-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Extend the bpf_fib_lookup() helper by making it to utilize mark if
the BPF_FIB_LOOKUP_MARK flag is set. In order to pass the mark the
four bytes of struct bpf_fib_lookup are used, shared with the
output-only smac/dmac fields.
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: David Ahern <dsahern@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240326101742.17421-2-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently bpf_get_current_pid_tgid() is allowed in tracing, cgroup
and sk_msg progs while bpf_get_ns_current_pid_tgid() is only allowed
in tracing progs.
We have an internal use case where for an application running
in a container (with pid namespace), user wants to get
the pid associated with the pid namespace in a cgroup bpf
program. Currently, cgroup bpf progs already allow
bpf_get_current_pid_tgid(). Let us allow bpf_get_ns_current_pid_tgid()
as well.
With auditing the code, bpf_get_current_pid_tgid() is also used
by sk_msg prog. But there are no side effect to expose these two
helpers to all prog types since they do not reveal any kernel specific
data. The detailed discussion is in [1].
So with this patch, both bpf_get_current_pid_tgid() and bpf_get_ns_current_pid_tgid()
are put in bpf_base_func_proto(), making them available to all
program types.
[1] https://lore.kernel.org/bpf/20240307232659.1115872-1-yonghong.song@linux.dev/
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20240315184854.2975190-1-yonghong.song@linux.dev
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
pull-request: bpf-next 2024-02-29
We've added 119 non-merge commits during the last 32 day(s) which contain
a total of 150 files changed, 3589 insertions(+), 995 deletions(-).
The main changes are:
1) Extend the BPF verifier to enable static subprog calls in spin lock
critical sections, from Kumar Kartikeya Dwivedi.
2) Fix confusing and incorrect inference of PTR_TO_CTX argument type
in BPF global subprogs, from Andrii Nakryiko.
3) Larger batch of riscv BPF JIT improvements and enabling inlining
of the bpf_kptr_xchg() for RV64, from Pu Lehui.
4) Allow skeleton users to change the values of the fields in struct_ops
maps at runtime, from Kui-Feng Lee.
5) Extend the verifier's capabilities of tracking scalars when they
are spilled to stack, especially when the spill or fill is narrowing,
from Maxim Mikityanskiy & Eduard Zingerman.
6) Various BPF selftest improvements to fix errors under gcc BPF backend,
from Jose E. Marchesi.
7) Avoid module loading failure when the module trying to register
a struct_ops has its BTF section stripped, from Geliang Tang.
8) Annotate all kfuncs in .BTF_ids section which eventually allows
for automatic kfunc prototype generation from bpftool, from Daniel Xu.
9) Several updates to the instruction-set.rst IETF standardization
document, from Dave Thaler.
10) Shrink the size of struct bpf_map resp. bpf_array,
from Alexei Starovoitov.
11) Initial small subset of BPF verifier prepwork for sleepable bpf_timer,
from Benjamin Tissoires.
12) Fix bpftool to be more portable to musl libc by using POSIX's
basename(), from Arnaldo Carvalho de Melo.
13) Add libbpf support to gcc in CORE macro definitions,
from Cupertino Miranda.
14) Remove a duplicate type check in perf_event_bpf_event,
from Florian Lehner.
15) Fix bpf_spin_{un,}lock BPF helpers to actually annotate them
with notrace correctly, from Yonghong Song.
16) Replace the deprecated bpf_lpm_trie_key 0-length array with flexible
array to fix build warnings, from Kees Cook.
17) Fix resolve_btfids cross-compilation to non host-native endianness,
from Viktor Malik.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (119 commits)
selftests/bpf: Test if shadow types work correctly.
bpftool: Add an example for struct_ops map and shadow type.
bpftool: Generated shadow variables for struct_ops maps.
libbpf: Convert st_ops->data to shadow type.
libbpf: Set btf_value_type_id of struct bpf_map for struct_ops.
bpf: Replace bpf_lpm_trie_key 0-length array with flexible array
bpf, arm64: use bpf_prog_pack for memory management
arm64: patching: implement text_poke API
bpf, arm64: support exceptions
arm64: stacktrace: Implement arch_bpf_stack_walk() for the BPF JIT
bpf: add is_async_callback_calling_insn() helper
bpf: introduce in_sleepable() helper
bpf: allow more maps in sleepable bpf programs
selftests/bpf: Test case for lacking CFI stub functions.
bpf: Check cfi_stubs before registering a struct_ops type.
bpf: Clarify batch lookup/lookup_and_delete semantics
bpf, docs: specify which BPF_ABS and BPF_IND fields were zero
bpf, docs: Fix typos in instruction-set.rst
selftests/bpf: update tcp_custom_syncookie to use scalar packet offset
bpf: Shrink size of struct bpf_map/bpf_array.
...
====================
Link: https://lore.kernel.org/r/20240301001625.8800-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
idev->cnf.forwarding and net->ipv6.devconf_all->forwarding
might be read locklessly, add appropriate READ_ONCE()
and WRITE_ONCE() annotations.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit marks kfuncs as such inside the .BTF_ids section. The upshot
of these annotations is that we'll be able to automatically generate
kfunc prototypes for downstream users. The process is as follows:
1. In source, use BTF_KFUNCS_START/END macro pair to mark kfuncs
2. During build, pahole injects into BTF a "bpf_kfunc" BTF_DECL_TAG for
each function inside BTF_KFUNCS sets
3. At runtime, vmlinux or module BTF is made available in sysfs
4. At runtime, bpftool (or similar) can look at provided BTF and
generate appropriate prototypes for functions with "bpf_kfunc" tag
To ensure future kfunc are similarly tagged, we now also return error
inside kfunc registration for untagged kfuncs. For vmlinux kfuncs,
we also WARN(), as initcall machinery does not handle errors.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/e55150ceecbf0a5d961e608941165c0bee7bc943.1706491398.git.dxu@dxuuu.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
pull-request: bpf-next 2024-01-26
We've added 107 non-merge commits during the last 4 day(s) which contain
a total of 101 files changed, 6009 insertions(+), 1260 deletions(-).
The main changes are:
1) Add BPF token support to delegate a subset of BPF subsystem
functionality from privileged system-wide daemons such as systemd
through special mount options for userns-bound BPF fs to a trusted
& unprivileged application. With addressed changes from Christian
and Linus' reviews, from Andrii Nakryiko.
2) Support registration of struct_ops types from modules which helps
projects like fuse-bpf that seeks to implement a new struct_ops type,
from Kui-Feng Lee.
3) Add support for retrieval of cookies for perf/kprobe multi links,
from Jiri Olsa.
4) Bigger batch of prep-work for the BPF verifier to eventually support
preserving boundaries and tracking scalars on narrowing fills,
from Maxim Mikityanskiy.
5) Extend the tc BPF flavor to support arbitrary TCP SYN cookies to help
with the scenario of SYN floods, from Kuniyuki Iwashima.
6) Add code generation to inline the bpf_kptr_xchg() helper which
improves performance when stashing/popping the allocated BPF objects,
from Hou Tao.
7) Extend BPF verifier to track aligned ST stores as imprecise spilled
registers, from Yonghong Song.
8) Several fixes to BPF selftests around inline asm constraints and
unsupported VLA code generation, from Jose E. Marchesi.
9) Various updates to the BPF IETF instruction set draft document such
as the introduction of conformance groups for instructions,
from Dave Thaler.
10) Fix BPF verifier to make infinite loop detection in is_state_visited()
exact to catch some too lax spill/fill corner cases,
from Eduard Zingerman.
11) Refactor the BPF verifier pointer ALU check to allow ALU explicitly
instead of implicitly for various register types, from Hao Sun.
12) Fix the flaky tc_redirect_dtime BPF selftest due to slowness
in neighbor advertisement at setup time, from Martin KaFai Lau.
13) Change BPF selftests to skip callback tests for the case when the
JIT is disabled, from Tiezhu Yang.
14) Add a small extension to libbpf which allows to auto create
a map-in-map's inner map, from Andrey Grafin.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (107 commits)
selftests/bpf: Add missing line break in test_verifier
bpf, docs: Clarify definitions of various instructions
bpf: Fix error checks against bpf_get_btf_vmlinux().
bpf: One more maintainer for libbpf and BPF selftests
selftests/bpf: Incorporate LSM policy to token-based tests
selftests/bpf: Add tests for LIBBPF_BPF_TOKEN_PATH envvar
libbpf: Support BPF token path setting through LIBBPF_BPF_TOKEN_PATH envvar
selftests/bpf: Add tests for BPF object load with implicit token
selftests/bpf: Add BPF object loading tests with explicit token passing
libbpf: Wire up BPF token support at BPF object level
libbpf: Wire up token_fd into feature probing logic
libbpf: Move feature detection code into its own file
libbpf: Further decouple feature checking logic from bpf_object
libbpf: Split feature detectors definitions from cached results
selftests/bpf: Utilize string values for delegate_xxx mount options
bpf: Support symbolic BPF FS delegation mount options
bpf: Fail BPF_TOKEN_CREATE if no delegation option was set on BPF FS
bpf,selinux: Allocate bpf_security_struct per BPF token
selftests/bpf: Add BPF token-enabled tests
libbpf: Add BPF token support to bpf_prog_load() API
...
====================
Link: https://lore.kernel.org/r/20240126215710.19855-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
XSK ZC Rx path calculates the size of data that will be posted to XSK Rx
queue via subtracting xdp_buff::data_end from xdp_buff::data.
In bpf_xdp_frags_increase_tail(), when underlying memory type of
xdp_rxq_info is MEM_TYPE_XSK_BUFF_POOL, add offset to data_end in tail
fragment, so that later on user space will be able to take into account
the amount of bytes added by XDP program.
Fixes: 24ea50127e ("xsk: support mbuf on ZC RX")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/r/20240124191602.566724-10-maciej.fijalkowski@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Remove remaining direct queries to perfmon_capable() and bpf_capable()
in BPF verifier logic and instead use BPF token (if available) to make
decisions about privileges.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-9-andrii@kernel.org
Instead of performing unconditional system-wide bpf_capable() and
perfmon_capable() calls inside bpf_base_func_proto() function (and other
similar ones) to determine eligibility of a given BPF helper for a given
program, use previously recorded BPF token during BPF_PROG_LOAD command
handling to inform the decision.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-8-andrii@kernel.org
This patch adds a new kfunc available at TC hook to support arbitrary
SYN Cookie.
The basic usage is as follows:
struct bpf_tcp_req_attrs attrs = {
.mss = mss,
.wscale_ok = wscale_ok,
.rcv_wscale = rcv_wscale, /* Server's WScale < 15 */
.snd_wscale = snd_wscale, /* Client's WScale < 15 */
.tstamp_ok = tstamp_ok,
.rcv_tsval = tsval,
.rcv_tsecr = tsecr, /* Server's Initial TSval */
.usec_ts_ok = usec_ts_ok,
.sack_ok = sack_ok,
.ecn_ok = ecn_ok,
}
skc = bpf_skc_lookup_tcp(...);
sk = (struct sock *)bpf_skc_to_tcp_sock(skc);
bpf_sk_assign_tcp_reqsk(skb, sk, attrs, sizeof(attrs));
bpf_sk_release(skc);
bpf_sk_assign_tcp_reqsk() takes skb, a listener sk, and struct
bpf_tcp_req_attrs and allocates reqsk and configures it. Then,
bpf_sk_assign_tcp_reqsk() links reqsk with skb and the listener.
The notable thing here is that we do not hold refcnt for both reqsk
and listener. To differentiate that, we mark reqsk->syncookie, which
is only used in TX for now. So, if reqsk->syncookie is 1 in RX, it
means that the reqsk is allocated by kfunc.
When skb is freed, sock_pfree() checks if reqsk->syncookie is 1,
and in that case, we set NULL to reqsk->rsk_listener before calling
reqsk_free() as reqsk does not hold a refcnt of the listener.
When the TCP stack looks up a socket from the skb, we steal the
listener from the reqsk in skb_steal_sock() and create a full sk
in cookie_v[46]_check().
The refcnt of reqsk will finally be set to 1 in tcp_get_cookie_sock()
after creating a full sk.
Note that we can extend struct bpf_tcp_req_attrs in the future when
we add a new attribute that is determined in 3WHS.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240115205514.68364-6-kuniyu@amazon.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Alexei Starovoitov says:
====================
pull-request: bpf-next 2023-12-18
This PR is larger than usual and contains changes in various parts
of the kernel.
The main changes are:
1) Fix kCFI bugs in BPF, from Peter Zijlstra.
End result: all forms of indirect calls from BPF into kernel
and from kernel into BPF work with CFI enabled. This allows BPF
to work with CONFIG_FINEIBT=y.
2) Introduce BPF token object, from Andrii Nakryiko.
It adds an ability to delegate a subset of BPF features from privileged
daemon (e.g., systemd) through special mount options for userns-bound
BPF FS to a trusted unprivileged application. The design accommodates
suggestions from Christian Brauner and Paul Moore.
Example:
$ sudo mkdir -p /sys/fs/bpf/token
$ sudo mount -t bpf bpffs /sys/fs/bpf/token \
-o delegate_cmds=prog_load:MAP_CREATE \
-o delegate_progs=kprobe \
-o delegate_attachs=xdp
3) Various verifier improvements and fixes, from Andrii Nakryiko, Andrei Matei.
- Complete precision tracking support for register spills
- Fix verification of possibly-zero-sized stack accesses
- Fix access to uninit stack slots
- Track aligned STACK_ZERO cases as imprecise spilled registers.
It improves the verifier "instructions processed" metric from single
digit to 50-60% for some programs.
- Fix verifier retval logic
4) Support for VLAN tag in XDP hints, from Larysa Zaremba.
5) Allocate BPF trampoline via bpf_prog_pack mechanism, from Song Liu.
End result: better memory utilization and lower I$ miss for calls to BPF
via BPF trampoline.
6) Fix race between BPF prog accessing inner map and parallel delete,
from Hou Tao.
7) Add bpf_xdp_get_xfrm_state() kfunc, from Daniel Xu.
It allows BPF interact with IPSEC infra. The intent is to support
software RSS (via XDP) for the upcoming ipsec pcpu work.
Experiments on AWS demonstrate single tunnel pcpu ipsec reaching
line rate on 100G ENA nics.
8) Expand bpf_cgrp_storage to support cgroup1 non-attach, from Yafang Shao.
9) BPF file verification via fsverity, from Song Liu.
It allows BPF progs get fsverity digest.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (164 commits)
bpf: Ensure precise is reset to false in __mark_reg_const_zero()
selftests/bpf: Add more uprobe multi fail tests
bpf: Fail uprobe multi link with negative offset
selftests/bpf: Test the release of map btf
s390/bpf: Fix indirect trampoline generation
selftests/bpf: Temporarily disable dummy_struct_ops test on s390
x86/cfi,bpf: Fix bpf_exception_cb() signature
bpf: Fix dtor CFI
cfi: Add CFI_NOSEAL()
x86/cfi,bpf: Fix bpf_struct_ops CFI
x86/cfi,bpf: Fix bpf_callback_t CFI
x86/cfi,bpf: Fix BPF JIT call
cfi: Flip headers
selftests/bpf: Add test for abnormal cnt during multi-kprobe attachment
selftests/bpf: Don't use libbpf_get_error() in kprobe_multi_test
selftests/bpf: Add test for abnormal cnt during multi-uprobe attachment
bpf: Limit the number of kprobes when attaching program to multiple kprobes
bpf: Limit the number of uprobes when attaching program to multiple uprobes
bpf: xdp: Register generic_kfunc_set with XDP programs
selftests/bpf: utilize string values for delegate_xxx mount options
...
====================
Link: https://lore.kernel.org/r/20231219000520.34178-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
optmem_max being used in tx zerocopy,
we want to be able to control it on a netns basis.
Following patch changes two tests.
Tested:
oqq130:~# cat /proc/sys/net/core/optmem_max
131072
oqq130:~# echo 1000000 >/proc/sys/net/core/optmem_max
oqq130:~# cat /proc/sys/net/core/optmem_max
1000000
oqq130:~# unshare -n
oqq130:~# cat /proc/sys/net/core/optmem_max
131072
oqq130:~# exit
logout
oqq130:~# cat /proc/sys/net/core/optmem_max
1000000
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove remaining direct queries to perfmon_capable() and bpf_capable()
in BPF verifier logic and instead use BPF token (if available) to make
decisions about privileges.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231130185229.2688956-9-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Instead of performing unconditional system-wide bpf_capable() and
perfmon_capable() calls inside bpf_base_func_proto() function (and other
similar ones) to determine eligibility of a given BPF helper for a given
program, use previously recorded BPF token during BPF_PROG_LOAD command
handling to inform the decision.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231130185229.2688956-8-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
tcp_hdr(skb) and SYN Cookie are passed to __cookie_v[46]_check(), but
none of the callers passes cookie other than ntohl(th->ack_seq) - 1.
Let's fetch it in __cookie_v[46]_check() instead of passing the cookie
over and over.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20231129022924.96156-5-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ndo_get_peer_dev is used in tcx BPF fast path, therefore make use of
indirect call wrapper and therefore optimize the bpf_redirect_peer()
internal handling a bit. Add a small skb_get_peer_dev() wrapper which
utilizes the INDIRECT_CALL_1() macro instead of open coding.
Future work could potentially add a peer pointer directly into struct
net_device in future and convert veth and netkit over to use it so
that eventually ndo_get_peer_dev can be removed.
Co-developed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20231114004220.6495-7-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Traffic redirected by bpf_redirect_peer() (used by recent CNIs like Cilium)
is not accounted for in the RX stats of supported devices (that is, veth
and netkit), confusing user space metrics collectors such as cAdvisor [0],
as reported by Youlun.
Fix it by calling dev_sw_netstats_rx_add() in skb_do_redirect(), to update
RX traffic counters. Devices that support ndo_get_peer_dev _must_ use the
@tstats per-CPU counters (instead of @lstats, or @dstats).
To make this more fool-proof, error out when ndo_get_peer_dev is set but
@tstats are not selected.
[0] Specifically, the "container_network_receive_{byte,packet}s_total"
counters are affected.
Fixes: 9aa1206e8f ("bpf: Add redirect_peer helper")
Reported-by: Youlun Zhang <zhangyoulun@bytedance.com>
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Co-developed-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20231114004220.6495-6-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
BPF kfuncs are meant to be called from BPF programs. Accordingly, most
kfuncs are not called from anywhere in the kernel, which the
-Wmissing-prototypes warning is unhappy about. We've peppered
__diag_ignore_all("-Wmissing-prototypes", ... everywhere kfuncs are
defined in the codebase to suppress this warning.
This patch adds two macros meant to bound one or many kfunc definitions.
All existing kfunc definitions which use these __diag calls to suppress
-Wmissing-prototypes are migrated to use the newly-introduced macros.
A new __diag_ignore_all - for "-Wmissing-declarations" - is added to the
__bpf_kfunc_start_defs macro based on feedback from Andrii on an earlier
version of this patch [0] and another recent mailing list thread [1].
In the future we might need to ignore different warnings or do other
kfunc-specific things. This change will make it easier to make such
modifications for all kfunc defs.
[0]: https://lore.kernel.org/bpf/CAEf4BzaE5dRWtK6RPLnjTW-MW9sx9K3Fn6uwqCTChK2Dcb1Xig@mail.gmail.com/
[1]: https://lore.kernel.org/bpf/ZT+2qCc%2FaXep0%2FLf@krava/
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20231031215625.2343848-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A few drivers were missing a xdp_do_flush() invocation after
XDP_REDIRECT.
Add three helper functions each for one of the per-CPU lists. Return
true if the per-CPU list is non-empty and flush the list.
Add xdp_do_check_flushed() which invokes each helper functions and
creates a warning if one of the functions had a non-empty list.
Hide everything behind CONFIG_DEBUG_NET.
Suggested-by: Jesper Dangaard Brouer <hawk@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20231016125738.Yt79p1uF@linutronix.de
These hooks allows intercepting connect(), getsockname(),
getpeername(), sendmsg() and recvmsg() for unix sockets. The unix
socket hooks get write access to the address length because the
address length is not fixed when dealing with unix sockets and
needs to be modified when a unix socket address is modified by
the hook. Because abstract socket unix addresses start with a
NUL byte, we cannot recalculate the socket address in kernelspace
after running the hook by calculating the length of the unix socket
path using strlen().
These hooks can be used when users want to multiplex syscall to a
single unix socket to multiple different processes behind the scenes
by redirecting the connect() and other syscalls to process specific
sockets.
We do not implement support for intercepting bind() because when
using bind() with unix sockets with a pathname address, this creates
an inode in the filesystem which must be cleaned up. If we rewrite
the address, the user might try to clean up the wrong file, leaking
the socket in the filesystem where it is never cleaned up. Until we
figure out a solution for this (and a use case for intercepting bind()),
we opt to not allow rewriting the sockaddr in bind() calls.
We also implement recvmsg() support for connected streams so that
after a connect() that is modified by a sockaddr hook, any corresponding
recmvsg() on the connected socket can also be modified to make the
connected program think it is connected to the "intended" remote.
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
Link: https://lore.kernel.org/r/20231011185113.140426-5-daan.j.demeyer@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
As prep for adding unix socket support to the cgroup sockaddr hooks,
let's add a kfunc bpf_sock_addr_set_sun_path() that allows modifying a unix
sockaddr from bpf. While this is already possible for AF_INET and AF_INET6,
we'll need this kfunc when we add unix socket support since modifying the
address for those requires modifying both the address and the sockaddr
length.
Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
Link: https://lore.kernel.org/r/20231011185113.140426-4-daan.j.demeyer@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Extend the bpf_fib_lookup() helper by making it to return the source
IPv4/IPv6 address if the BPF_FIB_LOOKUP_SRC flag is set.
For example, the following snippet can be used to derive the desired
source IP address:
struct bpf_fib_lookup p = { .ipv4_dst = ip4->daddr };
ret = bpf_skb_fib_lookup(skb, p, sizeof(p),
BPF_FIB_LOOKUP_SRC | BPF_FIB_LOOKUP_SKIP_NEIGH);
if (ret != BPF_FIB_LKUP_RET_SUCCESS)
return TC_ACT_SHOT;
/* the p.ipv4_src now contains the source address */
The inability to derive the proper source address may cause malfunctions
in BPF-based dataplanes for hosts containing netdevs with more than one
routable IP address or for multi-homed hosts.
For example, Cilium implements packet masquerading in BPF. If an
egressing netdev to which the Cilium's BPF prog is attached has
multiple IP addresses, then only one [hardcoded] IP address can be used for
masquerading. This breaks connectivity if any other IP address should have
been selected instead, for example, when a public and private addresses
are attached to the same egress interface.
The change was tested with Cilium [1].
Nikolay Aleksandrov helped to figure out the IPv6 addr selection.
[1]: https://github.com/cilium/cilium/pull/28283
Signed-off-by: Martynas Pumputis <m@lambda.lt>
Link: https://lore.kernel.org/r/20231007081415.33502-2-m@lambda.lt
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Syzkaller reported the following issue:
=======================================
Too BIG xdp->frame_sz = 131072
WARNING: CPU: 0 PID: 5020 at net/core/filter.c:4121
____bpf_xdp_adjust_tail net/core/filter.c:4121 [inline]
WARNING: CPU: 0 PID: 5020 at net/core/filter.c:4121
bpf_xdp_adjust_tail+0x466/0xa10 net/core/filter.c:4103
...
Call Trace:
<TASK>
bpf_prog_4add87e5301a4105+0x1a/0x1c
__bpf_prog_run include/linux/filter.h:600 [inline]
bpf_prog_run_xdp include/linux/filter.h:775 [inline]
bpf_prog_run_generic_xdp+0x57e/0x11e0 net/core/dev.c:4721
netif_receive_generic_xdp net/core/dev.c:4807 [inline]
do_xdp_generic+0x35c/0x770 net/core/dev.c:4866
tun_get_user+0x2340/0x3ca0 drivers/net/tun.c:1919
tun_chr_write_iter+0xe8/0x210 drivers/net/tun.c:2043
call_write_iter include/linux/fs.h:1871 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x650/0xe40 fs/read_write.c:584
ksys_write+0x12f/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
xdp->frame_sz > PAGE_SIZE check was introduced in commit c8741e2bfe
("xdp: Allow bpf_xdp_adjust_tail() to grow packet size"). But Jesper
Dangaard Brouer <jbrouer@redhat.com> noted that after introducing the
xdp_init_buff() which all XDP driver use - it's safe to remove this
check. The original intend was to catch cases where XDP drivers have
not been updated to use xdp.frame_sz, but that is not longer a concern
(since xdp_init_buff).
Running the initial syzkaller repro it was discovered that the
contiguous physical memory allocation is used for both xdp paths in
tun_get_user(), e.g. tun_build_skb() and tun_alloc_skb(). It was also
stated by Jesper Dangaard Brouer <jbrouer@redhat.com> that XDP can
work on higher order pages, as long as this is contiguous physical
memory (e.g. a page).
Reported-and-tested-by: syzbot+f817490f5bd20541b90a@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000774b9205f1d8a80d@google.com/T/
Link: https://syzkaller.appspot.com/bug?extid=f817490f5bd20541b90a
Link: https://lore.kernel.org/all/20230725155403.796-1-andrew.kanner@gmail.com/T/
Fixes: 43b5169d83 ("net, xdp: Introduce xdp_init_buff utility routine")
Signed-off-by: Andrew Kanner <andrew.kanner@gmail.com>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20230803190316.2380231-1-andrew.kanner@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently the bpf_sk_assign helper in tc BPF context refuses SO_REUSEPORT
sockets. This means we can't use the helper to steer traffic to Envoy,
which configures SO_REUSEPORT on its sockets. In turn, we're blocked
from removing TPROXY from our setup.
The reason that bpf_sk_assign refuses such sockets is that the
bpf_sk_lookup helpers don't execute SK_REUSEPORT programs. Instead,
one of the reuseport sockets is selected by hash. This could cause
dispatch to the "wrong" socket:
sk = bpf_sk_lookup_tcp(...) // select SO_REUSEPORT by hash
bpf_sk_assign(skb, sk) // SK_REUSEPORT wasn't executed
Fixing this isn't as simple as invoking SK_REUSEPORT from the lookup
helpers unfortunately. In the tc context, L2 headers are at the start
of the skb, while SK_REUSEPORT expects L3 headers instead.
Instead, we execute the SK_REUSEPORT program when the assigned socket
is pulled out of the skb, further up the stack. This creates some
trickiness with regards to refcounting as bpf_sk_assign will put both
refcounted and RCU freed sockets in skb->sk. reuseport sockets are RCU
freed. We can infer that the sk_assigned socket is RCU freed if the
reuseport lookup succeeds, but convincing yourself of this fact isn't
straight forward. Therefore we defensively check refcounting on the
sk_assign sock even though it's probably not required in practice.
Fixes: 8e368dc72e ("bpf: Fix use of sk->sk_reuseport from sk_assign")
Fixes: cf7fbe660f ("bpf: Add socket assign support")
Co-developed-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Joe Stringer <joe@cilium.io>
Link: https://lore.kernel.org/bpf/CACAyw98+qycmpQzKupquhkxbvWK4OFyDuuLMBNROnfWMZxUWeA@mail.gmail.com/
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/r/20230720-so-reuseport-v6-7-7021b683cdae@isovalent.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
The semantics for bpf_sk_assign are as follows:
sk = some_lookup_func()
bpf_sk_assign(skb, sk)
bpf_sk_release(sk)
That is, the sk is not consumed by bpf_sk_assign. The function
therefore needs to make sure that sk lives long enough to be
consumed from __inet_lookup_skb. The path through the stack for a
TCPv4 packet is roughly:
netif_receive_skb_core: takes RCU read lock
__netif_receive_skb_core:
sch_handle_ingress:
tcf_classify:
bpf_sk_assign()
deliver_ptype_list_skb:
deliver_skb:
ip_packet_type->func == ip_rcv:
ip_rcv_core:
ip_rcv_finish_core:
dst_input:
ip_local_deliver:
ip_local_deliver_finish:
ip_protocol_deliver_rcu:
tcp_v4_rcv:
__inet_lookup_skb:
skb_steal_sock
The existing helper takes advantage of the fact that everything
happens in the same RCU critical section: for sockets with
SOCK_RCU_FREE set bpf_sk_assign never takes a reference.
skb_steal_sock then checks SOCK_RCU_FREE again and does sock_put
if necessary.
This approach assumes that SOCK_RCU_FREE is never set on a sk
between bpf_sk_assign and skb_steal_sock, but this invariant is
violated by unhashed UDP sockets. A new UDP socket is created
in TCP_CLOSE state but without SOCK_RCU_FREE set. That flag is only
added in udp_lib_get_port() which happens when a socket is bound.
When bpf_sk_assign was added it wasn't possible to access unhashed
UDP sockets from BPF, so this wasn't a problem. This changed
in commit 0c48eefae7 ("sock_map: Lift socket state restriction
for datagram sockets"), but the helper wasn't adjusted accordingly.
The following sequence of events will therefore lead to a refcount
leak:
1. Add socket(AF_INET, SOCK_DGRAM) to a sockmap.
2. Pull socket out of sockmap and bpf_sk_assign it. Since
SOCK_RCU_FREE is not set we increment the refcount.
3. bind() or connect() the socket, setting SOCK_RCU_FREE.
4. skb_steal_sock will now set refcounted = false due to
SOCK_RCU_FREE.
5. tcp_v4_rcv() skips sock_put().
Fix the problem by rejecting unhashed sockets in bpf_sk_assign().
This matches the behaviour of __inet_lookup_skb which is ultimately
the goal of bpf_sk_assign().
Fixes: cf7fbe660f ("bpf: Add socket assign support")
Cc: Joe Stringer <joe@cilium.io>
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230720-so-reuseport-v6-2-7021b683cdae@isovalent.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This work refactors and adds a lightweight extension ("tcx") to the tc BPF
ingress and egress data path side for allowing BPF program management based
on fds via bpf() syscall through the newly added generic multi-prog API.
The main goal behind this work which we also presented at LPC [0] last year
and a recent update at LSF/MM/BPF this year [3] is to support long-awaited
BPF link functionality for tc BPF programs, which allows for a model of safe
ownership and program detachment.
Given the rise in tc BPF users in cloud native environments, this becomes
necessary to avoid hard to debug incidents either through stale leftover
programs or 3rd party applications accidentally stepping on each others toes.
As a recap, a BPF link represents the attachment of a BPF program to a BPF
hook point. The BPF link holds a single reference to keep BPF program alive.
Moreover, hook points do not reference a BPF link, only the application's
fd or pinning does. A BPF link holds meta-data specific to attachment and
implements operations for link creation, (atomic) BPF program update,
detachment and introspection. The motivation for BPF links for tc BPF programs
is multi-fold, for example:
- From Meta: "It's especially important for applications that are deployed
fleet-wide and that don't "control" hosts they are deployed to. If such
application crashes and no one notices and does anything about that, BPF
program will keep running draining resources or even just, say, dropping
packets. We at FB had outages due to such permanent BPF attachment
semantics. With fd-based BPF link we are getting a framework, which allows
safe, auto-detachable behavior by default, unless application explicitly
opts in by pinning the BPF link." [1]
- From Cilium-side the tc BPF programs we attach to host-facing veth devices
and phys devices build the core datapath for Kubernetes Pods, and they
implement forwarding, load-balancing, policy, EDT-management, etc, within
BPF. Currently there is no concept of 'safe' ownership, e.g. we've recently
experienced hard-to-debug issues in a user's staging environment where
another Kubernetes application using tc BPF attached to the same prio/handle
of cls_bpf, accidentally wiping all Cilium-based BPF programs from underneath
it. The goal is to establish a clear/safe ownership model via links which
cannot accidentally be overridden. [0,2]
BPF links for tc can co-exist with non-link attachments, and the semantics are
in line also with XDP links: BPF links cannot replace other BPF links, BPF
links cannot replace non-BPF links, non-BPF links cannot replace BPF links and
lastly only non-BPF links can replace non-BPF links. In case of Cilium, this
would solve mentioned issue of safe ownership model as 3rd party applications
would not be able to accidentally wipe Cilium programs, even if they are not
BPF link aware.
Earlier attempts [4] have tried to integrate BPF links into core tc machinery
to solve cls_bpf, which has been intrusive to the generic tc kernel API with
extensions only specific to cls_bpf and suboptimal/complex since cls_bpf could
be wiped from the qdisc also. Locking a tc BPF program in place this way, is
getting into layering hacks given the two object models are vastly different.
We instead implemented the tcx (tc 'express') layer which is an fd-based tc BPF
attach API, so that the BPF link implementation blends in naturally similar to
other link types which are fd-based and without the need for changing core tc
internal APIs. BPF programs for tc can then be successively migrated from classic
cls_bpf to the new tc BPF link without needing to change the program's source
code, just the BPF loader mechanics for attaching is sufficient.
For the current tc framework, there is no change in behavior with this change
and neither does this change touch on tc core kernel APIs. The gist of this
patch is that the ingress and egress hook have a lightweight, qdisc-less
extension for BPF to attach its tc BPF programs, in other words, a minimal
entry point for tc BPF. The name tcx has been suggested from discussion of
earlier revisions of this work as a good fit, and to more easily differ between
the classic cls_bpf attachment and the fd-based one.
For the ingress and egress tcx points, the device holds a cache-friendly array
with program pointers which is separated from control plane (slow-path) data.
Earlier versions of this work used priority to determine ordering and expression
of dependencies similar as with classic tc, but it was challenged that for
something more future-proof a better user experience is required. Hence this
resulted in the design and development of the generic attach/detach/query API
for multi-progs. See prior patch with its discussion on the API design. tcx is
the first user and later we plan to integrate also others, for example, one
candidate is multi-prog support for XDP which would benefit and have the same
'look and feel' from API perspective.
The goal with tcx is to have maximum compatibility to existing tc BPF programs,
so they don't need to be rewritten specifically. Compatibility to call into
classic tcf_classify() is also provided in order to allow successive migration
or both to cleanly co-exist where needed given its all one logical tc layer and
the tcx plus classic tc cls/act build one logical overall processing pipeline.
tcx supports the simplified return codes TCX_NEXT which is non-terminating (go
to next program) and terminating ones with TCX_PASS, TCX_DROP, TCX_REDIRECT.
The fd-based API is behind a static key, so that when unused the code is also
not entered. The struct tcx_entry's program array is currently static, but
could be made dynamic if necessary at a point in future. The a/b pair swap
design has been chosen so that for detachment there are no allocations which
otherwise could fail.
The work has been tested with tc-testing selftest suite which all passes, as
well as the tc BPF tests from the BPF CI, and also with Cilium's L4LB.
Thanks also to Nikolay Aleksandrov and Martin Lau for in-depth early reviews
of this work.
[0] https://lpc.events/event/16/contributions/1353/
[1] https://lore.kernel.org/bpf/CAEf4BzbokCJN33Nw_kg82sO=xppXnKWEncGTWCTB9vGCmLB6pw@mail.gmail.com
[2] https://colocatedeventseu2023.sched.com/event/1Jo6O/tales-from-an-ebpf-programs-murder-mystery-hemanth-malla-guillaume-fournier-datadog
[3] http://vger.kernel.org/bpfconf2023_material/tcx_meta_netdev_borkmann.pdf
[4] https://lore.kernel.org/bpf/20210604063116.234316-1-memxor@gmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230719140858.13224-3-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add multi-buffer support for AF_XDP by extending the XDP multi-buffer
support to be reflected in user-space when a packet is redirected to
an AF_XDP socket.
In the XDP implementation, the NIC driver builds the xdp_buff from the
first frag of the packet and adds any subsequent frags in the skb_shinfo
area of the xdp_buff. In AF_XDP core, XDP buffers are allocated from
xdp_sock's pool and data is copied from the driver's xdp_buff and frags.
Once an allocated XDP buffer is full and there is still data to be
copied, the 'XDP_PKT_CONTD' flag in'options' field of the corresponding
xdp ring descriptor is set and passed to the application. When application
sees the aforementioned flag set it knows there is pending data for this
packet that will be carried in the following descriptors. If there is no
more data to be copied, the flag in 'options' field is cleared for that
descriptor signalling EOP to the application.
If application reads a batch of descriptors using for example the libxdp
interfaces, it is not guaranteed that the batch will end with a full
packet. It might end in the middle of a packet and the rest of the frames
of that packet will arrive at the beginning of the next batch.
AF_XDP ensures that only a complete packet (along with all its frags) is
sent to application.
Signed-off-by: Tirthendu Sarkar <tirthendu.sarkar@intel.com>
Link: https://lore.kernel.org/r/20230719132421.584801-6-maciej.fijalkowski@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When calling bpf_sk_lookup_tcp(), bpf_sk_lookup_udp() or
bpf_skc_lookup_tcp() from tc/xdp ingress, VRF socket bindings aren't
respoected, i.e. unbound sockets are returned, and bound sockets aren't
found.
VRF binding is determined by the sdif argument to sk_lookup(), however
when called from tc the IP SKB control block isn't initialized and thus
inet{,6}_sdif() always returns 0.
Fix by calculating sdif for the tc/xdp flows by observing the device's
l3 enslaved state.
The cg/sk_skb hooking points which are expected to support
inet{,6}_sdif() pass sdif=-1 which makes __bpf_skc_lookup() use the
existing logic.
Fixes: 6acc9b432e ("bpf: Add helper to retrieve socket in BPF")
Signed-off-by: Gilad Sever <gilad9366@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Reviewed-by: Eyal Birger <eyal.birger@gmail.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Cc: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/bpf/20230621104211.301902-4-gilad9366@gmail.com
skb->dev always exists in the tc flow. There is no need to use
bpf_skc_lookup(), bpf_sk_lookup() from this code path.
This change facilitates fixing the tc flow to be VRF aware.
Signed-off-by: Gilad Sever <gilad9366@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Reviewed-by: Eyal Birger <eyal.birger@gmail.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230621104211.301902-3-gilad9366@gmail.com
Change BPF helper socket lookup functions to use TC specific variants:
bpf_tc_sk_lookup_tcp() / bpf_tc_sk_lookup_udp() / bpf_tc_skc_lookup_tcp()
instead of sharing implementation with the cg / sk_skb hooking points.
This allows introducing a separate logic for the TC flow.
The tc functions are identical to the original code.
Signed-off-by: Gilad Sever <gilad9366@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Reviewed-by: Eyal Birger <eyal.birger@gmail.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230621104211.301902-2-gilad9366@gmail.com
Currently we observed a significant performance degradation in
samples/bpf xdp1 and xdp2, due XDP multibuffer "xdp.frags" handling,
added in commit 7722517422 ("samples/bpf: fixup some tools to be able
to support xdp multibuffer").
This patch reduce the overhead by avoiding to read/load shared_info
(sinfo) memory area, when XDP packet don't have any frags. This improves
performance because sinfo is located in another cacheline.
Function bpf_xdp_pointer() is used by BPF helpers bpf_xdp_load_bytes()
and bpf_xdp_store_bytes(). As a help to reviewers, xdp_get_buff_len() can
potentially access sinfo, but it uses xdp_buff_has_frags() flags bit check
to avoid accessing sinfo in no-frags case.
The likely/unlikely instrumentation lays out asm code such that sinfo
access isn't interleaved with no-frags case (checked on GCC 12.2.1-4).
The generated asm code is more compact towards the no-frags case.
The BPF kfunc bpf_dynptr_slice() also use bpf_xdp_pointer(). Thus, it
should also take effect for that.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/168563651438.3436004.17735707525651776648.stgit@firesoul
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add ability to specify routing table ID to the `bpf_fib_lookup` BPF
helper.
A new field `tbid` is added to `struct bpf_fib_lookup` used as
parameters to the `bpf_fib_lookup` BPF helper.
When the helper is called with the `BPF_FIB_LOOKUP_DIRECT` and
`BPF_FIB_LOOKUP_TBID` flags the `tbid` field in `struct bpf_fib_lookup`
will be used as the table ID for the fib lookup.
If the `tbid` does not exist the fib lookup will fail with
`BPF_FIB_LKUP_RET_NOT_FWDED`.
The `tbid` field becomes a union over the vlan related output fields
in `struct bpf_fib_lookup` and will be zeroed immediately after usage.
This functionality is useful in containerized environments.
For instance, if a CNI wants to dictate the next-hop for traffic leaving
a container it can create a container-specific routing table and perform
a fib lookup against this table in a "host-net-namespace-side" TC program.
This functionality also allows `ip rule` like functionality at the TC
layer, allowing an eBPF program to pick a routing table based on some
aspect of the sk_buff.
As a concrete use case, this feature will be used in Cilium's SRv6 L3VPN
datapath.
When egress traffic leaves a Pod an eBPF program attached by Cilium will
determine which VRF the egress traffic should target, and then perform a
FIB lookup in a specific table representing this VRF's FIB.
Signed-off-by: Louis DeLosSantos <louis.delos.devel@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230505-bpf-add-tbid-fib-lookup-v2-1-0a31c22c748c@gmail.com
The socket destroy kfunc is used to forcefully terminate sockets from
certain BPF contexts. We plan to use the capability in Cilium
load-balancing to terminate client sockets that continue to connect to
deleted backends. The other use case is on-the-fly policy enforcement
where existing socket connections prevented by policies need to be
forcefully terminated. The kfunc also allows terminating sockets that may
or may not be actively sending traffic.
The kfunc can currently be called only from BPF TCP and UDP iterators
where users can filter, and terminate selected sockets. More
specifically, it can only be called from BPF contexts that ensure
socket locking in order to allow synchronous execution of protocol
specific `diag_destroy` handlers. The previous commit that batches UDP
sockets during iteration facilitated a synchronous invocation of the UDP
destroy callback from BPF context by skipping socket locks in
`udp_abort`. TCP iterator already supported batching of sockets being
iterated. To that end, `tracing_iter_filter` callback filter is added so
that verifier can restrict the kfunc to programs with `BPF_TRACE_ITER`
attach type, and reject other programs.
The kfunc takes `sock_common` type argument, even though it expects, and
casts them to a `sock` pointer. This enables the verifier to allow the
sock_destroy kfunc to be called for TCP with `sock_common` and UDP with
`sock` structs. Furthermore, as `sock_common` only has a subset of
certain fields of `sock`, casting pointer to the latter type might not
always be safe for certain sockets like request sockets, but these have a
special handling in the diag_destroy handlers.
Additionally, the kfunc is defined with `KF_TRUSTED_ARGS` flag to avoid the
cases where a `PTR_TO_BTF_ID` sk is obtained by following another pointer.
eg. getting a sk pointer (may be even NULL) by following another sk
pointer. The pointer socket argument passed in TCP and UDP iterators is
tagged as `PTR_TRUSTED` in {tcp,udp}_reg_info. The TRUSTED arg changes
are contributed by Martin KaFai Lau <martin.lau@kernel.org>.
Signed-off-by: Aditi Ghag <aditi.ghag@isovalent.com>
Link: https://lore.kernel.org/r/20230519225157.760788-8-aditi.ghag@isovalent.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
In one of our internal testing, we found a case where
- uapi struct bpf_tcp_sock is in vmlinux.h where vmlinux.h is not
generated from the testing kernel
- struct bpf_tcp_sock is not in vmlinux BTF
The above combination caused bpf load failure as the following
memory access
struct bpf_tcp_sock *tcp_sock = ...;
... tcp_sock->snd_cwnd ...
needs CORE relocation but the relocation cannot be resolved since
the kernel BTF does not have corresponding type.
Similar to other previous cases (nf_conn___init, tcp6_sock, mctcp_sock, etc.),
add the type to vmlinux BTF with BTF_EMIT_TYPE macro.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230502180543.1832140-1-yhs@fb.com
This adds minimal support for BPF_PROG_TYPE_NETFILTER bpf programs
that will be invoked via the NF_HOOK() points in the ip stack.
Invocation incurs an indirect call. This is not a necessity: Its
possible to add 'DEFINE_BPF_DISPATCHER(nf_progs)' and handle the
program invocation with the same method already done for xdp progs.
This isn't done here to keep the size of this chunk down.
Verifier restricts verdicts to either DROP or ACCEPT.
Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20230421170300.24115-3-fw@strlen.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
There are some use-cases where it is desirable to use bpf_redirect()
in combination with ifb device, which currently is not supported, for
example, around filtering inbound traffic with BPF to then push it to
ifb which holds the qdisc for shaping in contrast to doing that on the
egress device.
Toke mentions the following case related to OpenWrt:
Because there's not always a single egress on the other side. These are
mainly home routers, which tend to have one or more WiFi devices bridged
to one or more ethernet ports on the LAN side, and a single upstream WAN
port. And the objective is to control the total amount of traffic going
over the WAN link (in both directions), to deal with bufferbloat in the
ISP network (which is sadly still all too prevalent).
In this setup, the traffic can be split arbitrarily between the links
on the LAN side, and the only "single bottleneck" is the WAN link. So we
install both egress and ingress shapers on this, configured to something
like 95-98% of the true link bandwidth, thus moving the queues into the
qdisc layer in the router. It's usually necessary to set the ingress
bandwidth shaper a bit lower than the egress due to being "downstream"
of the bottleneck link, but it does work surprisingly well.
We usually use something like a matchall filter to put all ingress
traffic on the ifb, so doing the redirect from BPF has not been an
immediate requirement thus far. However, it does seem a bit odd that
this is not possible, and we do have a BPF-based filter that layers on
top of this kind of setup, which currently uses u32 as the ingress
filter and so it could presumably be improved to use BPF instead if
that was available.
Reported-by: Toke Høiland-Jørgensen <toke@redhat.com>
Reported-by: Yafang Shao <laoar.shao@gmail.com>
Reported-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://git.openwrt.org/?p=project/qosify.git;a=blob;f=README
Link: https://lore.kernel.org/bpf/875y9yzbuy.fsf@toke.dk
Link: https://lore.kernel.org/r/8cebc8b2b6e967e10cbafe2ffd6795050e74accd.1681739137.git.daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Jakub Kicinski