From 6095d5a271ad6dce30489526771a9040d78e0895 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Thu, 21 Jan 2021 21:22:03 +0100 Subject: libbpf: Use string table index from index table if needed For very large ELF objects (with many sections), we could get special value SHN_XINDEX (65535) for elf object's string table index - e_shstrndx. Call elf_getshdrstrndx to get the proper string table index, instead of reading it directly from ELF header. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210121202203.9346-4-jolsa@kernel.org --- tools/lib/bpf/btf.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 9970a288dda5..d9c10830d749 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -858,6 +858,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, Elf_Scn *scn = NULL; Elf *elf = NULL; GElf_Ehdr ehdr; + size_t shstrndx; if (elf_version(EV_CURRENT) == EV_NONE) { pr_warn("failed to init libelf for %s\n", path); @@ -882,7 +883,14 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, pr_warn("failed to get EHDR from %s\n", path); goto done; } - if (!elf_rawdata(elf_getscn(elf, ehdr.e_shstrndx), NULL)) { + + if (elf_getshdrstrndx(elf, &shstrndx)) { + pr_warn("failed to get section names section index for %s\n", + path); + goto done; + } + + if (!elf_rawdata(elf_getscn(elf, shstrndx), NULL)) { pr_warn("failed to get e_shstrndx from %s\n", path); goto done; } @@ -897,7 +905,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, idx, path); goto done; } - name = elf_strptr(elf, ehdr.e_shstrndx, sh.sh_name); + name = elf_strptr(elf, shstrndx, sh.sh_name); if (!name) { pr_warn("failed to get section(%d) name from %s\n", idx, path); -- cgit v1.2.3 From 78ed4045914c63054f2f377471b5a94f7006d61e Mon Sep 17 00:00:00 2001 From: Björn Töpel Date: Fri, 22 Jan 2021 11:53:51 +0100 Subject: libbpf, xsk: Select AF_XDP BPF program based on kernel version MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add detection for kernel version, and adapt the BPF program based on kernel support. This way, users will get the best possible performance from the BPF program. Signed-off-by: Björn Töpel Signed-off-by: Marek Majtyka Signed-off-by: Daniel Borkmann Reviewed-by: Maciej Fijalkowski Acked-by: Maciej Fijalkowski Link: https://lore.kernel.org/bpf/20210122105351.11751-4-bjorn.topel@gmail.com --- tools/lib/bpf/xsk.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 78 insertions(+), 3 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index e3e41ceeb1bc..20500fb1f17e 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -46,6 +46,11 @@ #define PF_XDP AF_XDP #endif +enum xsk_prog { + XSK_PROG_FALLBACK, + XSK_PROG_REDIRECT_FLAGS, +}; + struct xsk_umem { struct xsk_ring_prod *fill_save; struct xsk_ring_cons *comp_save; @@ -351,6 +356,54 @@ int xsk_umem__create_v0_0_2(struct xsk_umem **umem_ptr, void *umem_area, COMPAT_VERSION(xsk_umem__create_v0_0_2, xsk_umem__create, LIBBPF_0.0.2) DEFAULT_VERSION(xsk_umem__create_v0_0_4, xsk_umem__create, LIBBPF_0.0.4) +static enum xsk_prog get_xsk_prog(void) +{ + enum xsk_prog detected = XSK_PROG_FALLBACK; + struct bpf_load_program_attr prog_attr; + struct bpf_create_map_attr map_attr; + __u32 size_out, retval, duration; + char data_in = 0, data_out; + struct bpf_insn insns[] = { + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_MOV64_IMM(BPF_REG_3, XDP_PASS), + BPF_EMIT_CALL(BPF_FUNC_redirect_map), + BPF_EXIT_INSN(), + }; + int prog_fd, map_fd, ret; + + memset(&map_attr, 0, sizeof(map_attr)); + map_attr.map_type = BPF_MAP_TYPE_XSKMAP; + map_attr.key_size = sizeof(int); + map_attr.value_size = sizeof(int); + map_attr.max_entries = 1; + + map_fd = bpf_create_map_xattr(&map_attr); + if (map_fd < 0) + return detected; + + insns[0].imm = map_fd; + + memset(&prog_attr, 0, sizeof(prog_attr)); + prog_attr.prog_type = BPF_PROG_TYPE_XDP; + prog_attr.insns = insns; + prog_attr.insns_cnt = ARRAY_SIZE(insns); + prog_attr.license = "GPL"; + + prog_fd = bpf_load_program_xattr(&prog_attr, NULL, 0); + if (prog_fd < 0) { + close(map_fd); + return detected; + } + + ret = bpf_prog_test_run(prog_fd, 0, &data_in, 1, &data_out, &size_out, &retval, &duration); + if (!ret && retval == XDP_PASS) + detected = XSK_PROG_REDIRECT_FLAGS; + close(prog_fd); + close(map_fd); + return detected; +} + static int xsk_load_xdp_prog(struct xsk_socket *xsk) { static const int log_buf_size = 16 * 1024; @@ -358,7 +411,7 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk) char log_buf[log_buf_size]; int err, prog_fd; - /* This is the C-program: + /* This is the fallback C-program: * SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx) * { * int ret, index = ctx->rx_queue_index; @@ -414,9 +467,31 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk) /* The jumps are to this instruction */ BPF_EXIT_INSN(), }; - size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn); - prog_fd = bpf_load_program(BPF_PROG_TYPE_XDP, prog, insns_cnt, + /* This is the post-5.3 kernel C-program: + * SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx) + * { + * return bpf_redirect_map(&xsks_map, ctx->rx_queue_index, XDP_PASS); + * } + */ + struct bpf_insn prog_redirect_flags[] = { + /* r2 = *(u32 *)(r1 + 16) */ + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 16), + /* r1 = xskmap[] */ + BPF_LD_MAP_FD(BPF_REG_1, ctx->xsks_map_fd), + /* r3 = XDP_PASS */ + BPF_MOV64_IMM(BPF_REG_3, 2), + /* call bpf_redirect_map */ + BPF_EMIT_CALL(BPF_FUNC_redirect_map), + BPF_EXIT_INSN(), + }; + size_t insns_cnt[] = {sizeof(prog) / sizeof(struct bpf_insn), + sizeof(prog_redirect_flags) / sizeof(struct bpf_insn), + }; + struct bpf_insn *progs[] = {prog, prog_redirect_flags}; + enum xsk_prog option = get_xsk_prog(); + + prog_fd = bpf_load_program(BPF_PROG_TYPE_XDP, progs[option], insns_cnt[option], "LGPL-2.1 or BSD-2-Clause", 0, log_buf, log_buf_size); if (prog_fd < 0) { -- cgit v1.2.3 From 5f10c1aac8b29d225d19a74656865d1ee3db6eaa Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 3 Feb 2021 12:34:45 -0800 Subject: libbpf: Stop using feature-detection Makefiles Libbpf's Makefile relies on Linux tools infrastructure's feature detection framework, but libbpf's needs are very modest: it detects the presence of libelf and libz, both of which are mandatory. So it doesn't benefit much from the framework, but pays significant costs in terms of maintainability and debugging experience, when something goes wrong. The other feature detector, testing for the presernce of minimal BPF API in system headers is long obsolete as well, providing no value. So stop using feature detection and just assume the presence of libelf and libz during build time. Worst case, user will get a clear and actionable linker error, e.g.: /usr/bin/ld: cannot find -lelf On the other hand, we completely bypass recurring issues various users reported over time with false negatives of feature detection (libelf or libz not being detected, while they are actually present in the system). Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Randy Dunlap Link: https://lore.kernel.org/bpf/20210203203445.3356114-1-andrii@kernel.org --- tools/lib/bpf/.gitignore | 1 - tools/lib/bpf/Makefile | 47 ++++------------------------------------------- 2 files changed, 4 insertions(+), 44 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/.gitignore b/tools/lib/bpf/.gitignore index 8a81b3679d2b..5d4cfac671d5 100644 --- a/tools/lib/bpf/.gitignore +++ b/tools/lib/bpf/.gitignore @@ -1,7 +1,6 @@ # SPDX-License-Identifier: GPL-2.0-only libbpf_version.h libbpf.pc -FEATURE-DUMP.libbpf libbpf.so.* TAGS tags diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index 55bd78b3496f..887a494ad5fc 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -58,28 +58,7 @@ ifndef VERBOSE VERBOSE = 0 endif -FEATURE_USER = .libbpf -FEATURE_TESTS = libelf zlib bpf -FEATURE_DISPLAY = libelf zlib bpf - INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/include/uapi -FEATURE_CHECK_CFLAGS-bpf = $(INCLUDES) - -check_feat := 1 -NON_CHECK_FEAT_TARGETS := clean TAGS tags cscope help -ifdef MAKECMDGOALS -ifeq ($(filter-out $(NON_CHECK_FEAT_TARGETS),$(MAKECMDGOALS)),) - check_feat := 0 -endif -endif - -ifeq ($(check_feat),1) -ifeq ($(FEATURES_DUMP),) -include $(srctree)/tools/build/Makefile.feature -else -include $(FEATURES_DUMP) -endif -endif export prefix libdir src obj @@ -157,7 +136,7 @@ all: fixdep all_cmd: $(CMD_TARGETS) check -$(BPF_IN_SHARED): force elfdep zdep bpfdep $(BPF_HELPER_DEFS) +$(BPF_IN_SHARED): force $(BPF_HELPER_DEFS) @(test -f ../../include/uapi/linux/bpf.h -a -f ../../../include/uapi/linux/bpf.h && ( \ (diff -B ../../include/uapi/linux/bpf.h ../../../include/uapi/linux/bpf.h >/dev/null) || \ echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'" >&2 )) || true @@ -175,7 +154,7 @@ $(BPF_IN_SHARED): force elfdep zdep bpfdep $(BPF_HELPER_DEFS) echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/if_xdp.h' differs from latest version at 'include/uapi/linux/if_xdp.h'" >&2 )) || true $(Q)$(MAKE) $(build)=libbpf OUTPUT=$(SHARED_OBJDIR) CFLAGS="$(CFLAGS) $(SHLIB_FLAGS)" -$(BPF_IN_STATIC): force elfdep zdep bpfdep $(BPF_HELPER_DEFS) +$(BPF_IN_STATIC): force $(BPF_HELPER_DEFS) $(Q)$(MAKE) $(build)=libbpf OUTPUT=$(STATIC_OBJDIR) $(BPF_HELPER_DEFS): $(srctree)/tools/include/uapi/linux/bpf.h @@ -264,34 +243,16 @@ install_pkgconfig: $(PC_FILE) install: install_lib install_pkgconfig install_headers -### Cleaning rules - -config-clean: - $(call QUIET_CLEAN, feature-detect) - $(Q)$(MAKE) -C $(srctree)/tools/build/feature/ clean >/dev/null - -clean: config-clean +clean: $(call QUIET_CLEAN, libbpf) $(RM) -rf $(CMD_TARGETS) \ *~ .*.d .*.cmd LIBBPF-CFLAGS $(BPF_HELPER_DEFS) \ $(SHARED_OBJDIR) $(STATIC_OBJDIR) \ $(addprefix $(OUTPUT), \ *.o *.a *.so *.so.$(LIBBPF_MAJOR_VERSION) *.pc) - $(call QUIET_CLEAN, core-gen) $(RM) $(OUTPUT)FEATURE-DUMP.libbpf - - -PHONY += force elfdep zdep bpfdep cscope tags +PHONY += force cscope tags force: -elfdep: - @if [ "$(feature-libelf)" != "1" ]; then echo "No libelf found"; exit 1 ; fi - -zdep: - @if [ "$(feature-zlib)" != "1" ]; then echo "No zlib found"; exit 1 ; fi - -bpfdep: - @if [ "$(feature-bpf)" != "1" ]; then echo "BPF API too old"; exit 1 ; fi - cscope: ls *.c *.h > cscope.files cscope -b -q -I $(srctree)/include -f cscope.out -- cgit v1.2.3 From 1e0aa3fb05f8be0201e05a3f4e6c8910b9071e96 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 9 Feb 2021 14:18:26 -0800 Subject: libbpf: Use AF_LOCAL instead of AF_INET in xsk.c MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We have the environments where usage of AF_INET is prohibited (cgroup/sock_create returns EPERM for AF_INET). Let's use AF_LOCAL instead of AF_INET, it should perfectly work with SIOCETHTOOL. Signed-off-by: Stanislav Fomichev Signed-off-by: Andrii Nakryiko Tested-by: Björn Töpel Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/20210209221826.922940-1-sdf@google.com --- tools/lib/bpf/xsk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 20500fb1f17e..ffbb588724d8 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -517,7 +517,7 @@ static int xsk_get_max_queues(struct xsk_socket *xsk) struct ifreq ifr = {}; int fd, err, ret; - fd = socket(AF_INET, SOCK_DGRAM, 0); + fd = socket(AF_LOCAL, SOCK_DGRAM, 0); if (fd < 0) return -errno; -- cgit v1.2.3 From d2836dddc95d5dd82c7cb23726c97d8c9147f050 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Thu, 11 Feb 2021 18:10:30 -0800 Subject: libbpf: Ignore non function pointer member in struct_ops When libbpf initializes the kernel's struct_ops in "bpf_map__init_kern_struct_ops()", it enforces all pointer types must be a function pointer and rejects others. It turns out to be too strict. For example, when directly using "struct tcp_congestion_ops" from vmlinux.h, it has a "struct module *owner" member and it is set to NULL in a bpf_tcp_cc.o. Instead, it only needs to ensure the member is a function pointer if it has been set (relocated) to a bpf-prog. This patch moves the "btf_is_func_proto(kern_mtype)" check after the existing "if (!prog) { continue; }". The original debug message in "if (!prog) { continue; }" is also removed since it is no longer valid. Beside, there is a later debug message to tell which function pointer is set. The "btf_is_func_proto(mtype)" has already been guaranteed in "bpf_object__collect_st_ops_relos()" which has been run before "bpf_map__init_kern_struct_ops()". Thus, this check is removed. v2: - Remove outdated debug message (Andrii) Remove because there is a later debug message to tell which function pointer is set. - Following mtype->type is no longer needed. Remove: "skip_mods_and_typedefs(btf, mtype->type, &mtype_id)" - Do "if (!prog)" test before skip_mods_and_typedefs. Fixes: 590a00888250 ("bpf: libbpf: Add STRUCT_OPS support") Signed-off-by: Martin KaFai Lau Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210212021030.266932-1-kafai@fb.com --- tools/lib/bpf/libbpf.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 2abbc3800568..d43cc3f29dae 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -884,24 +884,24 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map, if (btf_is_ptr(mtype)) { struct bpf_program *prog; - mtype = skip_mods_and_typedefs(btf, mtype->type, &mtype_id); + prog = st_ops->progs[i]; + if (!prog) + continue; + kern_mtype = skip_mods_and_typedefs(kern_btf, kern_mtype->type, &kern_mtype_id); - if (!btf_is_func_proto(mtype) || - !btf_is_func_proto(kern_mtype)) { - pr_warn("struct_ops init_kern %s: non func ptr %s is not supported\n", + + /* mtype->type must be a func_proto which was + * guaranteed in bpf_object__collect_st_ops_relos(), + * so only check kern_mtype for func_proto here. + */ + if (!btf_is_func_proto(kern_mtype)) { + pr_warn("struct_ops init_kern %s: kernel member %s is not a func ptr\n", map->name, mname); return -ENOTSUP; } - prog = st_ops->progs[i]; - if (!prog) { - pr_debug("struct_ops init_kern %s: func ptr %s is not set\n", - map->name, mname); - continue; - } - prog->attach_btf_id = kern_type_id; prog->expected_attach_type = kern_member_idx; -- cgit v1.2.3