- 17 Sep, 2020 2 commits
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Maciej Fijalkowski authored
Previously, there was no need for poke descriptors being present in subprogram's bpf_prog_aux struct since tailcalls were simply not allowed in them. Each subprog is JITed independently so in order to enable JITing subprograms that use tailcalls, do the following: - in fixup_bpf_calls() store the index of tailcall insn onto the generated poke descriptor, - in case when insn patching occurs, adjust the tailcall insn idx from bpf_patch_insn_data, - then in jit_subprogs() check whether the given poke descriptor belongs to the current subprog by checking if that previously stored absolute index of tail call insn is in the scope of the insns of given subprog, - update the insn->imm with new poke descriptor slot so that while JITing the proper poke descriptor will be grabbed This way each of the main program's poke descriptors are distributed across the subprograms poke descriptor array, so main program's descriptors can be untracked out of the prog array map. Add also subprog's aux struct to the BPF map poke_progs list by calling on it map_poke_track(). In case of any error, call the map_poke_untrack() on subprog's aux structs that have already been registered to prog array map. Signed-off-by:
Maciej Fijalkowski <maciej.fijalkowski@intel.com> Signed-off-by:
Alexei Starovoitov <ast@kernel.org>
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Maciej Fijalkowski authored
Currently, %rax is used to store the jump target when BPF program is emitting the retpoline instructions that are handling the indirect tailcall. There is a plan to use %rax for different purpose, which is storing the tail call counter. In order to preserve this value across the tailcalls, adjust the BPF indirect tailcalls so that the target program will reside in %rcx and teach the retpoline instructions about new location of jump target. Signed-off-by:
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- 16 Sep, 2020 7 commits
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Andrii Nakryiko authored
Merge 183 tests from test_btf into test_progs framework to be exercised regularly. All the test_btf tests that were moved are modeled as proper sub-tests in test_progs framework for ease of debugging and reporting. No functional or behavioral changes were intended, I tried to preserve original behavior as much as possible. E.g., `test_progs -v` will activate "always_log" flag to emit BTF validation log. The only difference is in reducing the max_entries limit for pretty-printing tests from (128 * 1024) to just 128 to reduce tests running time without reducing the coverage. Example test run: $ sudo ./test_progs -n 8 ... #8 btf:OK Summary: 1/183 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by:
Andrii Nakryiko <andriin@fb.com> Signed-off-by:
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Alexei Starovoitov authored
Stanislav Fomichev says: ==================== Currently, if a user wants to store arbitrary metadata for an eBPF program, for example, the program build commit hash or version, they could store it in a map, and conveniently libbpf uses .data section to populate an internal map. However, if the program does not actually reference the map, then the map would be de-refcounted and freed. This patch set introduces a new syscall BPF_PROG_BIND_MAP to add a map to a program's used_maps, even if the program instructions does not reference the map. libbpf is extended to always BPF_PROG_BIND_MAP .rodata section so the metadata is kept in place. bpftool is also extended to print metadata in the 'bpftool prog' list. The variable is considered metadata if it starts with the magic 'bpf_metadata_' prefix; everything after the prefix is the metadata name. An example use of this would be BPF C file declaring: volatile const char bpf_metadata_commit_hash[] SEC(".rodata") = "abcdef123456"; and bpftool would emit: $ bpftool prog [...] metadata: commit_hash = "abcdef123456" v6 changes: * libbpf: drop FEAT_GLOBAL_DATA from probe_prog_bind_map (Andrii Nakryiko) * bpftool: combine find_metadata_map_id & find_metadata; drops extra bpf_map_get_fd_by_id and bpf_map_get_fd_by_id (Andrii Nakryiko) * bpftool: use strncmp instead of strstr (Andrii Nakryiko) * bpftool: memset(map_info) and extra empty line (Andrii Nakryiko) v5 changes: * selftest: verify that prog holds rodata (Andrii Nakryiko) * selftest: use volatile for metadata (Andrii Nakryiko) * bpftool: use sizeof in BPF_METADATA_PREFIX_LEN (Andrii Nakryiko) * bpftool: new find_metadata that does map lookup (Andrii Nakryiko) * libbpf: don't generalize probe_create_global_data (Andrii Nakryiko) * libbpf: use OPTS_VALID in bpf_prog_bind_map (Andrii Nakryiko) * libbpf: keep LIBBPF_0.2.0 sorted (Andrii Nakryiko) v4 changes: * Don't return EEXIST from syscall if already bound (Andrii Nakryiko) * Removed --metadata argument (Andrii Nakryiko) * Removed custom .metadata section (Alexei Starovoitov) * Addressed Andrii's suggestions about btf helpers and vsi (Andrii Nakryiko) * Moved bpf_prog_find_metadata into bpftool (Alexei Starovoitov) v3 changes: * API changes for bpf_prog_find_metadata (Toke Høiland-Jørgensen) v2 changes: * Made struct bpf_prog_bind_opts in libbpf so flags is optional. * Deduped probe_kern_global_data and probe_prog_bind_map into a common helper. * Added comment regarding why EEXIST is ignored in libbpf bind map. * Froze all LIBBPF_MAP_METADATA internal maps. * Moved bpf_prog_bind_map into new LIBBPF_0.1.1 in libbpf.map. * Added p_err() calls on error cases in bpftool show_prog_metadata. * Reverse christmas tree coding style in bpftool show_prog_metadata. * Made bpftool gen skeleton recognize .metadata as an internal map and generate datasec definition in skeleton. * Added C test using skeleton to see asset that the metadata is what we expect and rebinding causes EEXIST. v1 changes: * Fixed a few missing unlocks, and missing close while iterating map fds. * Move mutex initialization to right after prog aux allocation, and mutex destroy to right after prog aux free. * s/ADD_MAP/BIND_MAP/ * Use mutex only instead of RCU to protect the used_map array & count. Cc: YiFei Zhu <zhuyifei1999@gmail.com> ==================== Acked-by: -
YiFei Zhu authored
This is a simple test to check that loading and dumping metadata in btftool works, whether or not metadata contents are used by the program. A C test is also added to make sure the skeleton code can read the metadata values. Signed-off-by:
YiFei Zhu <zhuyifei@google.com> Signed-off-by:
Stanislav Fomichev <sdf@google.com> Signed-off-by:
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YiFei Zhu authored
Dump metadata in the 'bpftool prog' list if it's present. For some formatting some BTF code is put directly in the metadata dumping. Sanity checks on the map and the kind of the btf_type to make sure we are actually dumping what we are expecting. A helper jsonw_reset is added to json writer so we can reuse the same json writer without having extraneous commas. Sample output: $ bpftool prog 6: cgroup_skb name prog tag bcf7977d3b93787c gpl [...] btf_id 4 metadata: a = "foo" b = 1 $ bpftool prog --json --pretty [{ "id": 6, [...] "btf_id": 4, "metadata": { "a": "foo", "b": 1 } } ] Signed-off-by: -
YiFei Zhu authored
The patch adds a simple wrapper bpf_prog_bind_map around the syscall. When the libbpf tries to load a program, it will probe the kernel for the support of this syscall and unconditionally bind .rodata section to the program. Signed-off-by:
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YiFei Zhu authored
This syscall binds a map to a program. Returns success if the map is already bound to the program. Signed-off-by:
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YiFei Zhu authored
To support modifying the used_maps array, we use a mutex to protect the use of the counter and the array. The mutex is initialized right after the prog aux is allocated, and destroyed right before prog aux is freed. This way we guarantee it's initialized for both cBPF and eBPF. Signed-off-by:
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- 15 Sep, 2020 7 commits
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Yonghong Song authored
When syncing latest libbpf repo to bcc, ubuntu 16.04 (4.4.0 LTS kernel) failed compilation for xsk.c: In file included from /tmp/debuild.0jkauG/bcc/src/cc/libbpf/src/xsk.c:23:0: /tmp/debuild.0jkauG/bcc/src/cc/libbpf/src/xsk.c: In function ‘xsk_get_ctx’: /tmp/debuild.0jkauG/bcc/src/cc/libbpf/include/linux/list.h:81:9: warning: implicit declaration of function ‘container_of’ [-Wimplicit-function-declaration] container_of(ptr, type, member) ^ /tmp/debuild.0jkauG/bcc/src/cc/libbpf/include/linux/list.h:83:9: note: in expansion of macro ‘list_entry’ list_entry((ptr)->next, type, member) ... src/cc/CMakeFiles/bpf-static.dir/build.make:209: recipe for target 'src/cc/CMakeFiles/bpf-static.dir/libbpf/src/xsk.c.o' failed Commit 2f6324a3 ("libbpf: Support shared umems between queues and devices") added include file <linux/list.h>, which uses macro "container_of". xsk.c file also includes <linux/ethtool.h> before <linux/list.h>. In a more recent distro kernel, <linux/ethtool.h> includes <linux/kernel.h> which contains the macro definition for "container_of". So compilation is all fine. But in ubuntu 16.04 kernel, <linux/ethtool.h> does not contain <linux/kernel.h> which caused the above compilation error. Let explicitly add <linux/kernel.h> in xsk.c to avoid compilation error in old distro's. Fixes: 2f6324a3 ("libbpf: Support shared umems between queues and devices") Signed-off-by:Yonghong Song <yhs@fb.com> Signed-off-by:
Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200914223210.1831262-1-yhs@fb.com
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Yonghong Song authored
When building bpf selftests like make -C tools/testing/selftests/bpf -j20 I hit the following errors: ... GEN /net-next/tools/testing/selftests/bpf/tools/build/bpftool/Documentation/bpftool-gen.8 <stdin>:75: (WARNING/2) Block quote ends without a blank line; unexpected unindent. <stdin>:71: (WARNING/2) Literal block ends without a blank line; unexpected unindent. <stdin>:85: (WARNING/2) Literal block ends without a blank line; unexpected unindent. <stdin>:57: (WARNING/2) Block quote ends without a blank line; unexpected unindent. <stdin>:66: (WARNING/2) Literal block ends without a blank line; unexpected unindent. <stdin>:109: (WARNING/2) Literal block ends without a blank line; unexpected unindent. <stdin>:175: (WARNING/2) Literal block ends without a blank line; unexpected unindent. <stdin>:273: (WARNING/2) Literal block ends without a blank line; unexpected unindent. make[1]: *** [/net-next/tools/testing/selftests/bpf/tools/build/bpftool/Documentation/bpftool-perf.8] Error 12 make[1]: *** Waiting for unfinished jobs.... make[1]: *** [/net-next/tools/testing/selftests/bpf/tools/build/bpftool/Documentation/bpftool-iter.8] Error 12 make[1]: *** [/net-next/tools/testing/selftests/bpf/tools/build/bpftool/Documentation/bpftool-struct_ops.8] Error 12 ... I am using: -bash-4.4$ rst2man --version rst2man (Docutils 0.11 [repository], Python 2.7.5, on linux2) -bash-4.4$ The Makefile generated final .rst file (e.g., bpftool-cgroup.rst) looks like ... ID AttachType AttachFlags Name \n SEE ALSO\n========\n\t**bpf**\ (2),\n\t**bpf-helpers**\ (7),\n\t**bpftool**\ (8),\n\t**bpftool-btf**\ (8),\n\t**bpftool-feature**\ (8),\n\t**bpftool-gen**\ (8),\n\t**bpftool-iter**\ (8),\n\t**bpftool-link**\ (8),\n\t**bpftool-map**\ (8),\n\t**bpftool-net**\ (8),\n\t**bpftool-perf**\ (8),\n\t**bpftool-prog**\ (8),\n\t**bpftool-struct_ops**\ (8)\n The rst2man generated .8 file looks like Literal block ends without a blank line; unexpected unindent. .sp n SEEALSOn========nt**bpf**(2),nt**bpf\-helpers**(7),nt**bpftool**(8),nt**bpftool\-btf**(8),nt** bpftool\-feature**(8),nt**bpftool\-gen**(8),nt**bpftool\-iter**(8),nt**bpftool\-link**(8),nt** bpftool\-map**(8),nt**bpftool\-net**(8),nt**bpftool\-perf**(8),nt**bpftool\-prog**(8),nt** bpftool\-struct_ops**(8)n Looks like that particular version of rst2man prefers to have actual new line instead of \n. Since `echo -e` may not be available in some environment, let us use `printf`. Format string "%b" is used for `printf` to ensure all escape characters are interpretted properly. Fixes: 18841da9 ("tools: bpftool: Automate generation for "SEE ALSO" sections in man pages") Suggested-by:Andrii Nakryiko <andrii.nakryiko@gmail.com> Signed-off-by:
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Magnus Karlsson authored
Fix a potential refcount warning that a zero value is increased to one in xp_dma_map, by initializing the refcount to one to start with, instead of zero plus a refcount_inc(). Fixes: 921b6869 ("xsk: Enable sharing of dma mappings") Signed-off-by:
Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by:
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Magnus Karlsson authored
Add a quiet option (-Q) that disables the statistics print outs of xdpsock. This is good to have when measuring 0% loss rate performance as it will be quite terrible if the application uses printfs. Signed-off-by:
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Magnus Karlsson authored
Fix a possible deadlock in the l2fwd application in xdpsock that can occur when there is no space in the Tx ring. There are two ways to get the kernel to consume entries in the Tx ring: calling sendto() to make it send packets and freeing entries from the completion ring, as the kernel will not send a packet if there is no space for it to add a completion entry in the completion ring. The Tx loop in l2fwd only used to call sendto(). This patches adds cleaning the completion ring in that loop. Signed-off-by:
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Magnus Karlsson authored
Fix the sending of a single packet (or small burst) in xdpsock when executing in copy mode. Currently, the l2fwd application in xdpsock only transmits the packets after a batch of them has been received, which might be confusing if you only send one packet and expect that it is returned pronto. Fix this by calling sendto() more often and add a comment in the code that states that this can be optimized if needed. Reported-by:
Tirthendu Sarkar <tirthendu.sarkar@intel.com> Signed-off-by:
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Ilya Leoshkevich authored
In order to branch around tail calls (due to out-of-bounds index, exceeding tail call count or missing tail call target), JIT uses label[0] field, which contains the address of the instruction following the tail call. When there are multiple tail calls, label[0] value comes from handling of a previous tail call, which is incorrect. Fix by getting rid of label array and resolving the label address locally: for all 3 branches that jump to it, emit 0 offsets at the beginning, and then backpatch them with the correct value. Also, do not use the long jump infrastructure: the tail call sequence is known to be short, so make all 3 jumps short. Fixes: 6651ee07 ("s390/bpf: implement bpf_tail_call() helper") Signed-off-by:
Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by:
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- 11 Sep, 2020 14 commits
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Alexei Starovoitov authored
Neal Cardwell says: ==================== This patch series reorganizes TCP congestion control initialization so that if EBPF code called by tcp_init_transfer() sets the congestion control algorithm by calling setsockopt(TCP_CONGESTION) then the TCP stack initializes the congestion control module immediately, instead of having tcp_init_transfer() later initialize the congestion control module. This increases flexibility for the EBPF code that runs at connection establishment time, and simplifies the code. This has the following benefits: (1) This allows CC module customizations made by the EBPF called in tcp_init_transfer() to persist, and not be wiped out by a later call to tcp_init_congestion_control() in tcp_init_transfer(). (2) Does not flip the order of EBPF and CC init, to avoid causing bugs for existing code upstream that depends on the current order. (3) Does not cause 2 initializations for for CC in the case where the EBPF called in tcp_init_transfer() wants to set the CC to a new CC algorithm. (4) Allows follow-on simplifications to the code in net/core/filter.c and net/ipv4/tcp_cong.c, which currently both have some complexity to special-case CC initialization to avoid double CC initialization if EBPF sets the CC. changes in v2: o rebase onto bpf-next o add another follow-on simplification suggested by Martin KaFai Lau: "tcp: simplify tcp_set_congestion_control() load=false case" changes in v3: o no change in commits o resent patch series from @gmail.com, since mail from ncardwell@google.com stopped being accepted at netdev@vger.kernel.org mid-way through processing the v2 patch series (between patches 2 and 3), confusing patchwork about which patches belonged to the v2 patch series ==================== Acked-by:Martin KaFai Lau <kafai@fb.com> Signed-off-by:
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Neal Cardwell authored
Simplify tcp_set_congestion_control() by removing the initialization code path for the !load case. There are only two call sites for tcp_set_congestion_control(). The EBPF call site is the only one that passes load=false; it also passes cap_net_admin=true. Because of that, the exact same behavior can be achieved by removing the special if (!load) branch of the logic. Both before and after this commit, the EBPF case will call bpf_try_module_get(), and if that succeeds then call tcp_reinit_congestion_control() or if that fails then return EBUSY. Note that this returns the logic to a structure very similar to the structure before: commit 91b5b21c ("bpf: Add support for changing congestion control") except that the CAP_NET_ADMIN status is passed in as a function argument. This clean-up was suggested by Martin KaFai Lau. Suggested-by:
Neal Cardwell <ncardwell@google.com> Signed-off-by:
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Neal Cardwell authored
Now that the previous patches have removed the code that uses the flags argument to _bpf_setsockopt(), we can remove that argument. Signed-off-by:
Eric Dumazet <edumazet@google.com> Signed-off-by:
Yuchung Cheng <ycheng@google.com> Acked-by:
Kevin Yang <yyd@google.com> Cc: Lawrence Brakmo <brakmo@fb.com>
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Neal Cardwell authored
Now that the previous patches ensure that all call sites for tcp_set_congestion_control() want to initialize congestion control, we can simplify tcp_set_congestion_control() by removing the reinit argument and the code to support it. Signed-off-by:
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Neal Cardwell authored
Now that the previous patch ensures we don't initialize the congestion control twice, when EBPF sets the congestion control algorithm at connection establishment we can simplify the code by simply initializing the congestion control module at that time. Signed-off-by:
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Neal Cardwell authored
Change tcp_init_transfer() to only initialize congestion control if it has not been initialized already. With this new approach, we can arrange things so that if the EBPF code sets the congestion control by calling setsockopt(TCP_CONGESTION) then tcp_init_transfer() will not re-initialize the CC module. This is an approach that has the following beneficial properties: (1) This allows CC module customizations made by the EBPF called in tcp_init_transfer() to persist, and not be wiped out by a later call to tcp_init_congestion_control() in tcp_init_transfer(). (2) Does not flip the order of EBPF and CC init, to avoid causing bugs for existing code upstream that depends on the current order. (3) Does not cause 2 initializations for for CC in the case where the EBPF called in tcp_init_transfer() wants to set the CC to a new CC algorithm. (4) Allows follow-on simplifications to the code in net/core/filter.c and net/ipv4/tcp_cong.c, which currently both have some complexity to special-case CC initialization to avoid double CC initialization if EBPF sets the CC. Signed-off-by: -
Quentin Monnet authored
The "SEE ALSO" sections of bpftool's manual pages refer to bpf(2), bpf-helpers(7), then all existing bpftool man pages (save the current one). This leads to nearly-identical lists being duplicated in all manual pages. Ideally, when a new page is created, all lists should be updated accordingly, but this has led to omissions and inconsistencies multiple times in the past. Let's take it out of the RST files and generate the "SEE ALSO" sections automatically in the Makefile when generating the man pages. The lists are not really useful in the RST anyway because all other pages are available in the same directory. v3: - Fix conflict with a previous patchset that introduced RST2MAN_OPTS variable passed to rst2man. v2: - Use "echo -n" instead of "printf" in Makefile, to avoid any risk of passing a format string directly to the command. Signed-off-by:
Quentin Monnet <quentin@isovalent.com> Signed-off-by:
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Song Liu authored
This should be "current" not "skb". Fixes: c6b5fb86 ("bpf: add documentation for eBPF helpers (42-50)") Signed-off-by:
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Yonghong Song authored
When tweaking llvm optimizations, I found that selftest build failed with the following error: libbpf: elf: skipping unrecognized data section(6) .rodata.str1.1 libbpf: prog 'sysctl_tcp_mem': bad map relo against '.L__const.is_tcp_mem.tcp_mem_name' in section '.rodata.str1.1' Error: failed to open BPF object file: Relocation failed make: *** [/work/net-next/tools/testing/selftests/bpf/test_sysctl_prog.skel.h] Error 255 make: *** Deleting file `/work/net-next/tools/testing/selftests/bpf/test_sysctl_prog.skel.h' The local string constant "tcp_mem_name" is put into '.rodata.str1.1' section which libbpf cannot handle. Using untweaked upstream llvm, "tcp_mem_name" is completely inlined after loop unrolling. Commit 7fb5eefd ("selftests/bpf: Fix test_sysctl_loop{1, 2} failure due to clang change") solved a similar problem by defining the string const as a global. Let us do the same here for test_sysctl_prog.c so it can weather future potential llvm changes. Signed-off-by: -
Ilya Leoshkevich authored
On non-SMP kernels __per_cpu_start is not 0, so look it up in kallsyms. Signed-off-by:
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Lorenz Bauer authored
As Alexei points out, struct bpf_sk_lookup_kern has two 4-byte holes. This leads to suboptimal instructions being generated (IPv4, x86): 1372 struct bpf_sk_lookup_kern ctx = { 0xffffffff81b87f30 <+624>: xor %eax,%eax 0xffffffff81b87f32 <+626>: mov $0x6,%ecx 0xffffffff81b87f37 <+631>: lea 0x90(%rsp),%rdi 0xffffffff81b87f3f <+639>: movl $0x110002,0x88(%rsp) 0xffffffff81b87f4a <+650>: rep stos %rax,%es:(%rdi) 0xffffffff81b87f4d <+653>: mov 0x8(%rsp),%eax 0xffffffff81b87f51 <+657>: mov %r13d,0x90(%rsp) 0xffffffff81b87f59 <+665>: incl %gs:0x7e4970a0(%rip) 0xffffffff81b87f60 <+672>: mov %eax,0x8c(%rsp) 0xffffffff81b87f67 <+679>: movzwl 0x10(%rsp),%eax 0xffffffff81b87f6c <+684>: mov %ax,0xa8(%rsp) 0xffffffff81b87f74 <+692>: movzwl 0x38(%rsp),%eax 0xffffffff81b87f79 <+697>: mov %ax,0xaa(%rsp) Fix this by moving around sport and dport. pahole confirms there are no more holes: struct bpf_sk_lookup_kern { u16 family; /* 0 2 */ u16 protocol; /* 2 2 */ __be16 sport; /* 4 2 */ u16 dport; /* 6 2 */ struct { __be32 saddr; /* 8 4 */ __be32 daddr; /* 12 4 */ } v4; /* 8 8 */ struct { const struct in6_addr * saddr; /* 16 8 */ const struct in6_addr * daddr; /* 24 8 */ } v6; /* 16 16 */ struct sock * selected_sk; /* 32 8 */ bool no_reuseport; /* 40 1 */ /* size: 48, cachelines: 1, members: 8 */ /* padding: 7 */ /* last cacheline: 48 bytes */ }; The assembly also doesn't contain the pesky rep stos anymore: 1372 struct bpf_sk_lookup_kern ctx = { 0xffffffff81b87f60 <+624>: movzwl 0x10(%rsp),%eax 0xffffffff81b87f65 <+629>: movq $0x0,0xa8(%rsp) 0xffffffff81b87f71 <+641>: movq $0x0,0xb0(%rsp) 0xffffffff81b87f7d <+653>: mov %ax,0x9c(%rsp) 0xffffffff81b87f85 <+661>: movzwl 0x38(%rsp),%eax 0xffffffff81b87f8a <+666>: movq $0x0,0xb8(%rsp) 0xffffffff81b87f96 <+678>: mov %ax,0x9e(%rsp) 0xffffffff81b87f9e <+686>: mov 0x8(%rsp),%eax 0xffffffff81b87fa2 <+690>: movq $0x0,0xc0(%rsp) 0xffffffff81b87fae <+702>: movl $0x110002,0x98(%rsp) 0xffffffff81b87fb9 <+713>: mov %eax,0xa0(%rsp) 0xffffffff81b87fc0 <+720>: mov %r13d,0xa4(%rsp) 1: https://lore.kernel.org/bpf/CAADnVQKE6y9h2fwX6OS837v-Uf+aBXnT_JXiN_bbo2gitZQ3tA@mail.gmail.com/ Fixes: e9ddbb77 ("bpf: Introduce SK_LOOKUP program type with a dedicated attach point") Suggested-by:Lorenz Bauer <lmb@cloudflare.com> Signed-off-by:
Jesper Dangaard Brouer <brouer@redhat.com> Link: https://lore.kernel.org/bpf/20200910110248.198326-1-lmb@cloudflare.com
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Quentin Monnet authored
There is no support for creating maps of types array-of-map or hash-of-map in bpftool. This is because the kernel needs an inner_map_fd to collect metadata on the inner maps to be supported by the new map, but bpftool does not provide a way to pass this file descriptor. Add a new optional "inner_map" keyword that can be used to pass a reference to a map, retrieve a fd to that map, and pass it as the inner_map_fd. Add related documentation and bash completion. Note that we can reference the inner map by its name, meaning we can have several times the keyword "name" with different meanings (mandatory outer map name, and possibly a name to use to find the inner_map_fd). The bash completion will offer it just once, and will not suggest "name" on the following command: # bpftool map create /sys/fs/bpf/my_outer_map type hash_of_maps \ inner_map name my_inner_map [TAB] Fixing that specific case seems too convoluted. Completion will work as expected, however, if the outer map name comes first and the "inner_map name ..." is passed second. Signed-off-by: -
Quentin Monnet authored
When dumping outer maps or prog_array maps, and on lookup failure, bpftool simply skips the entry with no error message. This is because the kernel returns non-zero when no value is found for the provided key, which frequently happen for those maps if they have not been filled. When such a case occurs, errno is set to ENOENT. It seems unlikely we could receive other error codes at this stage (we successfully retrieved map info just before), but to be on the safe side, let's skip the entry only if errno was ENOENT, and not for the other errors. v3: New patch Signed-off-by:
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Quentin Monnet authored
The function used to dump a map entry in bpftool is a bit difficult to follow, as a consequence to earlier refactorings. There is a variable ("num_elems") which does not appear to be necessary, and the error handling would look cleaner if moved to its own function. Let's clean it up. No functional change. v2: - v1 was erroneously removing the check on fd maps in an attempt to get support for outer map dumps. This is already working. Instead, v2 focuses on cleaning up the dump_map_elem() function, to avoid similar confusion in the future. Signed-off-by:
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- 10 Sep, 2020 8 commits
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Lorenz Bauer authored
Add a test that exercises a basic sockmap / sockhash iteration. For now we simply count the number of elements seen. Once sockmap update from iterators works we can extend this to perform a full copy. Signed-off-by:
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Lorenz Bauer authored
Add bpf_iter support for sockmap / sockhash, based on the bpf_sk_storage and hashtable implementation. sockmap and sockhash share the same iteration context: a pointer to an arbitrary key and a pointer to a socket. Both pointers may be NULL, and so BPF has to perform a NULL check before accessing them. Technically it's not possible for sockhash iteration to yield a NULL socket, but we ignore this to be able to use a single iteration point. Iteration will visit all keys that remain unmodified during the lifetime of the iterator. It may or may not visit newly added ones. Switch from using rcu_dereference_raw to plain rcu_dereference, so we gain another guard rail if CONFIG_PROVE_RCU is enabled. Signed-off-by:
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Lorenz Bauer authored
The lookup paths for sockmap and sockhash currently include a check that returns NULL if the socket we just found is not a full socket. However, this check is not necessary. On insertion we ensure that we have a full socket (caveat around sock_ops), so request sockets are not a problem. Time-wait sockets are allocated separate from the original socket and then fed into the hashdance. They don't affect the sockets already stored in the sockmap. Suggested-by:
Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by:
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Quentin Monnet authored
Nearly all man pages for bpftool have the same common set of option flags (--help, --version, --json, --pretty, --debug). The description is duplicated across all the pages, which is more difficult to maintain if the description of an option changes. It may also be confusing to sort out what options are not "common" and should not be copied when creating new manual pages. Let's move the description for those common options to a separate file, which is included with a RST directive when generating the man pages. Signed-off-by:
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Quentin Monnet authored
Bpftool has a number of features that can be included or left aside during compilation. This includes: - Support for libbfd, providing the disassembler for JIT-compiled programs. - Support for BPF skeletons, used for profiling programs or iterating on the PIDs of processes associated with BPF objects. In order to make it easy for users to understand what features were compiled for a given bpftool binary, print the status of the two features above when showing the version number for bpftool ("bpftool -V" or "bpftool version"). Document this in the main manual page. Example invocations: $ bpftool version ./bpftool v5.9.0-rc1 features: libbfd, skeletons $ bpftool -p version { "version": "5.9.0-rc1", "features": { "libbfd": true, "skeletons": true } } Some other parameters are optional at compilation ("DISASM_FOUR_ARGS_SIGNATURE", LIBCAP support) but they do not impact significantly bpftool's behaviour from a user's point of view, so their status is not reported. Available commands and supported program types depend on the version number, and are therefore not reported either. Note that they are already available, albeit without JSON, via bpftool's help messages. v3: - Use a simple list instead of boolean values for plain output. v2: - Fix JSON (object instead or array for the features). Signed-off-by: -
Quentin Monnet authored
eBPF selftests include a script to check that bpftool builds correctly with different command lines. Let's add one build for bpftool's documentation so as to detect errors or warning reported by rst2man when compiling the man pages. Also add a build to the selftests Makefile to make sure we build bpftool documentation along with bpftool when building the selftests. This also builds and checks warnings for the man page for eBPF helpers, which is built along bpftool's documentation. This change adds rst2man as a dependency for selftests (it comes with Python's "docutils"). v2: - Use "--exit-status=1" option for rst2man instead of counting lines from stderr. - Also build bpftool as part as the selftests build (and not only when the tests are actually run). Signed-off-by:
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Quentin Monnet authored
To build man pages for bpftool (and for eBPF helper functions), rst2man can log different levels of information. Let's make it log all levels to keep the RST files clean. Doing so, rst2man complains about double colons, used for literal blocks, that look like underlines for section titles. Let's add the necessary blank lines. v2: - Use "--verbose" instead of "-r 1" (same behaviour but more readable). - Pass it through a RST2MAN_OPTS variable so we can easily pass other options too. Signed-off-by:
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Chen Zhou authored
Remove duplicate headers which are included twice. Signed-off-by:
Chen Zhou <chenzhou10@huawei.com> Signed-off-by:
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- 09 Sep, 2020 2 commits
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Andrii Nakryiko authored
Switch from deprecated bpf_program__title() API to bpf_program__section_name(). Also drop unnecessary error checks because neither bpf_program__title() nor bpf_program__section_name() can fail or return NULL. Fixes: 52109584 ("libbpf: Deprecate notion of BPF program "title" in favor of "section name"") Signed-off-by:
Tobias Klauser <tklauser@distanz.ch> Acked-by:
Jiri Olsa <jolsa@redhat.com> Link: https://lore.kernel.org/bpf/20200908180127.1249-1-andriin@fb.com
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Yonghong Song authored
Andrii reported that with latest clang, when building selftests, we have error likes: error: progs/test_sysctl_loop1.c:23:16: in function sysctl_tcp_mem i32 (%struct.bpf_sysctl*): Looks like the BPF stack limit of 512 bytes is exceeded. Please move large on stack variables into BPF per-cpu array map. The error is triggered by the following LLVM patch: https://reviews.llvm.org/D87134 For example, the following code is from test_sysctl_loop1.c: static __always_inline int is_tcp_mem(struct bpf_sysctl *ctx) { volatile char tcp_mem_name[] = "net/ipv4/tcp_mem/very_very_very_very_long_pointless_string"; ... } Without the above LLVM patch, the compiler did optimization to load the string (59 bytes long) with 7 64bit loads, 1 8bit load and 1 16bit load, occupying 64 byte stack size. With the above LLVM patch, the compiler only uses 8bit loads, but subregister is 32bit. So stack requirements become 4 * 59 = 236 bytes. Together with other stuff on the stack, total stack size exceeds 512 bytes, hence compiler complains and quits. To fix the issue, removing "volatile" key word or changing "volatile" to "const"/"static const" does not work, the string is put in .rodata.str1.1 section, which libbpf did not process it and errors out with libbpf: elf: skipping unrecognized data section(6) .rodata.str1.1 libbpf: prog 'sysctl_tcp_mem': bad map relo against '.L__const.is_tcp_mem.tcp_mem_name' in section '.rodata.str1.1' Defining the string const as global variable can fix the issue as it puts the string constant in '.rodata' section which is recognized by libbpf. In the future, when libbpf can process '.rodata.str*.*' properly, the global definition can be changed back to local definition. Defining tcp_mem_name as a global, however, triggered a verifier failure. ./test_progs -n 7/21 libbpf: load bpf program failed: Permission denied libbpf: -- BEGIN DUMP LOG --- libbpf: invalid stack off=0 size=1 verification time 6975 usec stack depth 160+64 processed 889 insns (limit 1000000) max_states_per_insn 4 total_states 14 peak_states 14 mark_read 10 libbpf: -- END LOG -- libbpf: failed to load program 'sysctl_tcp_mem' libbpf: failed to load object 'test_sysctl_loop2.o' test_bpf_verif_scale:FAIL:114 #7/21 test_sysctl_loop2.o:FAIL This actually exposed a bpf program bug. In test_sysctl_loop{1,2}, we have code like const char tcp_mem_name[] = "<...long string...>"; ... char name[64]; ... for (i = 0; i < sizeof(tcp_mem_name); ++i) if (name[i] != tcp_mem_name[i]) return 0; In the above code, if sizeof(tcp_mem_name) > 64, name[i] access may be out of bound. The sizeof(tcp_mem_name) is 59 for test_sysctl_loop1.c and 79 for test_sysctl_loop2.c. Without promotion-to-global change, old compiler generates code where the overflowed stack access is actually filled with valid value, so hiding the bpf program bug. With promotion-to-global change, the code is different, more specifically, the previous loading constants to stack is gone, and "name" occupies stack[-64:0] and overflow access triggers a verifier error. To fix the issue, adjust "name" buffer size properly. Reported-by:
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