linux-dev - Linux kernel development work

Age	Commit message (Collapse)	Author	Files	Lines
2022-02-02	selftests/bpf: Migrate from bpf_prog_test_run_xattr	Delyan Kratunov	1	-5/+5
	bpf_prog_test_run_xattr is being deprecated in favor of the OPTS-based bpf_prog_test_run_opts. We end up unable to use CHECK_ATTR so replace usages with ASSERT_* calls. Also, prog_run_xattr is now prog_run_opts. Signed-off-by: Delyan Kratunov <delyank@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220202235423.1097270-3-delyank@fb.com
2021-01-20	bpf: Remove extra lock_sock for TCP_ZEROCOPY_RECEIVE	Stanislav Fomichev	1	-0/+1
	Add custom implementation of getsockopt hook for TCP_ZEROCOPY_RECEIVE. We skip generic hooks for TCP_ZEROCOPY_RECEIVE and have a custom call in do_tcp_getsockopt using the on-stack data. This removes 3% overhead for locking/unlocking the socket. Without this patch: 3.38% 0.07% tcp_mmap [kernel.kallsyms] [k] __cgroup_bpf_run_filter_getsockopt \| --3.30%--__cgroup_bpf_run_filter_getsockopt \| --0.81%--__kmalloc With the patch applied: 0.52% 0.12% tcp_mmap [kernel.kallsyms] [k] __cgroup_bpf_run_filter_getsockopt_kern Note, exporting uapi/tcp.h requires removing netinet/tcp.h from test_progs.h because those headers have confliciting definitions. Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210115163501.805133-2-sdf@google.com
2020-09-03	selftests/bpf: Add __noinline variant of cls_redirect selftest	Andrii Nakryiko	1	-15/+57
	As one of the most complicated and close-to-real-world programs, cls_redirect is a good candidate to exercise libbpf's logic of handling bpf2bpf calls. So add variant with using explicit __noinline for majority of functions except few most basic ones. If those few functions are inlined, verifier starts to complain about program instruction limit of 1mln instructions being exceeded, most probably due to instruction overhead of doing a sub-program call. Convert user-space part of selftest to have to sub-tests: with and without inlining. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: Lorenz Bauer <lmb@cloudflare.com> Link: https://lore.kernel.org/bpf/20200903203542.15944-15-andriin@fb.com
2020-04-26	selftests/bpf: Add cls_redirect classifier	Lorenz Bauer	1	-0/+456
	cls_redirect is a TC clsact based replacement for the glb-redirect iptables module available at [1]. It enables what GitHub calls "second chance" flows [2], similarly proposed by the Beamer paper [3]. In contrast to glb-redirect, it also supports migrating UDP flows as long as connected sockets are used. cls_redirect is in production at Cloudflare, as part of our own L4 load balancer. We have modified the encapsulation format slightly from glb-redirect: glbgue_chained_routing.private_data_type has been repurposed to form a version field and several flags. Both have been arranged in a way that a private_data_type value of zero matches the current glb-redirect behaviour. This means that cls_redirect will understand packets in glb-redirect format, but not vice versa. The test suite only covers basic features. For example, cls_redirect will correctly forward path MTU discovery packets, but this is not exercised. It is also possible to switch the encapsulation format to GRE on the last hop, which is also not tested. There are two major distinctions from glb-redirect: first, cls_redirect relies on receiving encapsulated packets directly from a router. This is because we don't have access to the neighbour tables from BPF, yet. See forward_to_next_hop for details. Second, cls_redirect performs decapsulation instead of using separate ipip and sit tunnel devices. This avoids issues with the sit tunnel [4] and makes deploying the classifier easier: decapsulated packets appear on the same interface, so existing firewall rules continue to work as expected. The code base started it's life on v4.19, so there are most likely still hold overs from old workarounds. In no particular order: - The function buf_off is required to defeat a clang optimization that leads to the verifier rejecting the program due to pointer arithmetic in the wrong order. - The function pkt_parse_ipv6 is force inlined, because it would otherwise be rejected due to returning a pointer to stack memory. - The functions fill_tuple and classify_tcp contain kludges, because we've run out of function arguments. - The logic in general is rather nested, due to verifier restrictions. I think this is either because the verifier loses track of constants on the stack, or because it can't track enum like variables. 1: https://github.com/github/glb-director/tree/master/src/glb-redirect 2: https://github.com/github/glb-director/blob/master/docs/development/second-chance-design.md 3: https://www.usenix.org/conference/nsdi18/presentation/olteanu 4: https://github.com/github/glb-director/issues/64 Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200424185556.7358-2-lmb@cloudflare.com