diff options
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/include/uapi/linux/bpf.h | 22 | ||||
| -rw-r--r-- | tools/lib/bpf/bpf.c | 34 | ||||
| -rw-r--r-- | tools/lib/bpf/bpf.h | 19 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 46 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.h | 8 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.map | 4 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/cgroup_link.c | 244 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/test_cgroup_link.c | 24 |
8 files changed, 399 insertions, 2 deletions
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 9f786a5a44ac..2e29a671d67e 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -111,6 +111,8 @@ enum bpf_cmd { BPF_MAP_LOOKUP_AND_DELETE_BATCH, BPF_MAP_UPDATE_BATCH, BPF_MAP_DELETE_BATCH, + BPF_LINK_CREATE, + BPF_LINK_UPDATE, }; enum bpf_map_type { @@ -541,7 +543,7 @@ union bpf_attr { __u32 prog_cnt; } query; - struct { + struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */ __u64 name; __u32 prog_fd; } raw_tracepoint; @@ -569,6 +571,24 @@ union bpf_attr { __u64 probe_offset; /* output: probe_offset */ __u64 probe_addr; /* output: probe_addr */ } task_fd_query; + + struct { /* struct used by BPF_LINK_CREATE command */ + __u32 prog_fd; /* eBPF program to attach */ + __u32 target_fd; /* object to attach to */ + __u32 attach_type; /* attach type */ + __u32 flags; /* extra flags */ + } link_create; + + struct { /* struct used by BPF_LINK_UPDATE command */ + __u32 link_fd; /* link fd */ + /* new program fd to update link with */ + __u32 new_prog_fd; + __u32 flags; /* extra flags */ + /* expected link's program fd; is specified only if + * BPF_F_REPLACE flag is set in flags */ + __u32 old_prog_fd; + } link_update; + } __attribute__((aligned(8))); /* The description below is an attempt at providing documentation to eBPF diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 73220176728d..5cc1b0785d18 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -585,6 +585,40 @@ int bpf_prog_detach2(int prog_fd, int target_fd, enum bpf_attach_type type) return sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr)); } +int bpf_link_create(int prog_fd, int target_fd, + enum bpf_attach_type attach_type, + const struct bpf_link_create_opts *opts) +{ + union bpf_attr attr; + + if (!OPTS_VALID(opts, bpf_link_create_opts)) + return -EINVAL; + + memset(&attr, 0, sizeof(attr)); + attr.link_create.prog_fd = prog_fd; + attr.link_create.target_fd = target_fd; + attr.link_create.attach_type = attach_type; + + return sys_bpf(BPF_LINK_CREATE, &attr, sizeof(attr)); +} + +int bpf_link_update(int link_fd, int new_prog_fd, + const struct bpf_link_update_opts *opts) +{ + union bpf_attr attr; + + if (!OPTS_VALID(opts, bpf_link_update_opts)) + return -EINVAL; + + memset(&attr, 0, sizeof(attr)); + attr.link_update.link_fd = link_fd; + attr.link_update.new_prog_fd = new_prog_fd; + attr.link_update.flags = OPTS_GET(opts, flags, 0); + attr.link_update.old_prog_fd = OPTS_GET(opts, old_prog_fd, 0); + + return sys_bpf(BPF_LINK_UPDATE, &attr, sizeof(attr)); +} + int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags, __u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt) { diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index b976e77316cc..46d47afdd887 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -168,6 +168,25 @@ LIBBPF_API int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type); LIBBPF_API int bpf_prog_detach2(int prog_fd, int attachable_fd, enum bpf_attach_type type); +struct bpf_link_create_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ +}; +#define bpf_link_create_opts__last_field sz + +LIBBPF_API int bpf_link_create(int prog_fd, int target_fd, + enum bpf_attach_type attach_type, + const struct bpf_link_create_opts *opts); + +struct bpf_link_update_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + __u32 flags; /* extra flags */ + __u32 old_prog_fd; /* expected old program FD */ +}; +#define bpf_link_update_opts__last_field old_prog_fd + +LIBBPF_API int bpf_link_update(int link_fd, int new_prog_fd, + const struct bpf_link_update_opts *opts); + struct bpf_prog_test_run_attr { int prog_fd; int repeat; diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 0638e717f502..ff9174282a8c 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -6978,6 +6978,12 @@ struct bpf_link { bool disconnected; }; +/* Replace link's underlying BPF program with the new one */ +int bpf_link__update_program(struct bpf_link *link, struct bpf_program *prog) +{ + return bpf_link_update(bpf_link__fd(link), bpf_program__fd(prog), NULL); +} + /* Release "ownership" of underlying BPF resource (typically, BPF program * attached to some BPF hook, e.g., tracepoint, kprobe, etc). Disconnected * link, when destructed through bpf_link__destroy() call won't attempt to @@ -7533,6 +7539,46 @@ static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec, return bpf_program__attach_lsm(prog); } +struct bpf_link * +bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd) +{ + const struct bpf_sec_def *sec_def; + enum bpf_attach_type attach_type; + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int prog_fd, link_fd; + + prog_fd = bpf_program__fd(prog); + if (prog_fd < 0) { + pr_warn("program '%s': can't attach before loaded\n", + bpf_program__title(prog, false)); + return ERR_PTR(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return ERR_PTR(-ENOMEM); + link->detach = &bpf_link__detach_fd; + + attach_type = bpf_program__get_expected_attach_type(prog); + if (!attach_type) { + sec_def = find_sec_def(bpf_program__title(prog, false)); + if (sec_def) + attach_type = sec_def->attach_type; + } + link_fd = bpf_link_create(prog_fd, cgroup_fd, attach_type, NULL); + if (link_fd < 0) { + link_fd = -errno; + free(link); + pr_warn("program '%s': failed to attach to cgroup: %s\n", + bpf_program__title(prog, false), + libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); + return ERR_PTR(link_fd); + } + link->fd = link_fd; + return link; +} + struct bpf_link *bpf_program__attach(struct bpf_program *prog) { const struct bpf_sec_def *sec_def; diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 55348724c355..44df1d3e7287 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -224,6 +224,8 @@ LIBBPF_API int bpf_link__fd(const struct bpf_link *link); LIBBPF_API const char *bpf_link__pin_path(const struct bpf_link *link); LIBBPF_API int bpf_link__pin(struct bpf_link *link, const char *path); LIBBPF_API int bpf_link__unpin(struct bpf_link *link); +LIBBPF_API int bpf_link__update_program(struct bpf_link *link, + struct bpf_program *prog); LIBBPF_API void bpf_link__disconnect(struct bpf_link *link); LIBBPF_API int bpf_link__destroy(struct bpf_link *link); @@ -245,13 +247,17 @@ bpf_program__attach_tracepoint(struct bpf_program *prog, LIBBPF_API struct bpf_link * bpf_program__attach_raw_tracepoint(struct bpf_program *prog, const char *tp_name); - LIBBPF_API struct bpf_link * bpf_program__attach_trace(struct bpf_program *prog); LIBBPF_API struct bpf_link * bpf_program__attach_lsm(struct bpf_program *prog); +LIBBPF_API struct bpf_link * +bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd); + struct bpf_map; + LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map); + struct bpf_insn; /* diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index eabd3d3e689f..bb8831605b25 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -243,7 +243,11 @@ LIBBPF_0.0.8 { bpf_link__pin; bpf_link__pin_path; bpf_link__unpin; + bpf_link__update_program; + bpf_link_create; + bpf_link_update; bpf_map__set_initial_value; + bpf_program__attach_cgroup; bpf_program__attach_lsm; bpf_program__is_lsm; bpf_program__set_attach_target; diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_link.c b/tools/testing/selftests/bpf/prog_tests/cgroup_link.c new file mode 100644 index 000000000000..6e04f8d1d15b --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/cgroup_link.c @@ -0,0 +1,244 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <test_progs.h> +#include "cgroup_helpers.h" +#include "test_cgroup_link.skel.h" + +static __u32 duration = 0; +#define PING_CMD "ping -q -c1 -w1 127.0.0.1 > /dev/null" + +static struct test_cgroup_link *skel = NULL; + +int ping_and_check(int exp_calls, int exp_alt_calls) +{ + skel->bss->calls = 0; + skel->bss->alt_calls = 0; + CHECK_FAIL(system(PING_CMD)); + if (CHECK(skel->bss->calls != exp_calls, "call_cnt", + "exp %d, got %d\n", exp_calls, skel->bss->calls)) + return -EINVAL; + if (CHECK(skel->bss->alt_calls != exp_alt_calls, "alt_call_cnt", + "exp %d, got %d\n", exp_alt_calls, skel->bss->alt_calls)) + return -EINVAL; + return 0; +} + +void test_cgroup_link(void) +{ + struct { + const char *path; + int fd; + } cgs[] = { + { "/cg1" }, + { "/cg1/cg2" }, + { "/cg1/cg2/cg3" }, + { "/cg1/cg2/cg3/cg4" }, + }; + int last_cg = ARRAY_SIZE(cgs) - 1, cg_nr = ARRAY_SIZE(cgs); + DECLARE_LIBBPF_OPTS(bpf_link_update_opts, link_upd_opts); + struct bpf_link *links[ARRAY_SIZE(cgs)] = {}, *tmp_link; + __u32 prog_ids[ARRAY_SIZE(cgs)], prog_cnt = 0, attach_flags; + int i = 0, err, prog_fd; + bool detach_legacy = false; + + skel = test_cgroup_link__open_and_load(); + if (CHECK(!skel, "skel_open_load", "failed to open/load skeleton\n")) + return; + prog_fd = bpf_program__fd(skel->progs.egress); + + err = setup_cgroup_environment(); + if (CHECK(err, "cg_init", "failed: %d\n", err)) + goto cleanup; + + for (i = 0; i < cg_nr; i++) { + cgs[i].fd = create_and_get_cgroup(cgs[i].path); + if (CHECK(cgs[i].fd < 0, "cg_create", "fail: %d\n", cgs[i].fd)) + goto cleanup; + } + + err = join_cgroup(cgs[last_cg].path); + if (CHECK(err, "cg_join", "fail: %d\n", err)) + goto cleanup; + + for (i = 0; i < cg_nr; i++) { + links[i] = bpf_program__attach_cgroup(skel->progs.egress, + cgs[i].fd); + if (CHECK(IS_ERR(links[i]), "cg_attach", "i: %d, err: %ld\n", + i, PTR_ERR(links[i]))) + goto cleanup; + } + + ping_and_check(cg_nr, 0); + + /* query the number of effective progs and attach flags in root cg */ + err = bpf_prog_query(cgs[0].fd, BPF_CGROUP_INET_EGRESS, + BPF_F_QUERY_EFFECTIVE, &attach_flags, NULL, + &prog_cnt); + CHECK_FAIL(err); + CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI); + if (CHECK(prog_cnt != 1, "effect_cnt", "exp %d, got %d\n", 1, prog_cnt)) + goto cleanup; + + /* query the number of effective progs in last cg */ + err = bpf_prog_query(cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS, + BPF_F_QUERY_EFFECTIVE, NULL, NULL, + &prog_cnt); + CHECK_FAIL(err); + CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI); + if (CHECK(prog_cnt != cg_nr, "effect_cnt", "exp %d, got %d\n", + cg_nr, prog_cnt)) + goto cleanup; + + /* query the effective prog IDs in last cg */ + err = bpf_prog_query(cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS, + BPF_F_QUERY_EFFECTIVE, &attach_flags, + prog_ids, &prog_cnt); + CHECK_FAIL(err); + CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI); + if (CHECK(prog_cnt != cg_nr, "effect_cnt", "exp %d, got %d\n", + cg_nr, prog_cnt)) + goto cleanup; + for (i = 1; i < prog_cnt; i++) { + CHECK(prog_ids[i - 1] != prog_ids[i], "prog_id_check", + "idx %d, prev id %d, cur id %d\n", + i, prog_ids[i - 1], prog_ids[i]); + } + + /* detach bottom program and ping again */ + bpf_link__destroy(links[last_cg]); + links[last_cg] = NULL; + + ping_and_check(cg_nr - 1, 0); + + /* mix in with non link-based multi-attachments */ + err = bpf_prog_attach(prog_fd, cgs[last_cg].fd, + BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_MULTI); + if (CHECK(err, "cg_attach_legacy", "errno=%d\n", errno)) + goto cleanup; + detach_legacy = true; + + links[last_cg] = bpf_program__attach_cgroup(skel->progs.egress, + cgs[last_cg].fd); + if (CHECK(IS_ERR(links[last_cg]), "cg_attach", "err: %ld\n", + PTR_ERR(links[last_cg]))) + goto cleanup; + + ping_and_check(cg_nr + 1, 0); + + /* detach link */ + bpf_link__destroy(links[last_cg]); + links[last_cg] = NULL; + + /* detach legacy */ + err = bpf_prog_detach2(prog_fd, cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS); + if (CHECK(err, "cg_detach_legacy", "errno=%d\n", errno)) + goto cleanup; + detach_legacy = false; + + /* attach legacy exclusive prog attachment */ + err = bpf_prog_attach(prog_fd, cgs[last_cg].fd, + BPF_CGROUP_INET_EGRESS, 0); + if (CHECK(err, "cg_attach_exclusive", "errno=%d\n", errno)) + goto cleanup; + detach_legacy = true; + + /* attempt to mix in with multi-attach bpf_link */ + tmp_link = bpf_program__attach_cgroup(skel->progs.egress, + cgs[last_cg].fd); + if (CHECK(!IS_ERR(tmp_link), "cg_attach_fail", "unexpected success!\n")) { + bpf_link__destroy(tmp_link); + goto cleanup; + } + + ping_and_check(cg_nr, 0); + + /* detach */ + err = bpf_prog_detach2(prog_fd, cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS); + if (CHECK(err, "cg_detach_legacy", "errno=%d\n", errno)) + goto cleanup; + detach_legacy = false; + + ping_and_check(cg_nr - 1, 0); + + /* attach back link-based one */ + links[last_cg] = bpf_program__attach_cgroup(skel->progs.egress, + cgs[last_cg].fd); + if (CHECK(IS_ERR(links[last_cg]), "cg_attach", "err: %ld\n", + PTR_ERR(links[last_cg]))) + goto cleanup; + + ping_and_check(cg_nr, 0); + + /* check legacy exclusive prog can't be attached */ + err = bpf_prog_attach(prog_fd, cgs[last_cg].fd, + BPF_CGROUP_INET_EGRESS, 0); + if (CHECK(!err, "cg_attach_exclusive", "unexpected success")) { + bpf_prog_detach2(prog_fd, cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS); + goto cleanup; + } + + /* replace BPF programs inside their links for all but first link */ + for (i = 1; i < cg_nr; i++) { + err = bpf_link__update_program(links[i], skel->progs.egress_alt); + if (CHECK(err, "prog_upd", "link #%d\n", i)) + goto cleanup; + } + + ping_and_check(1, cg_nr - 1); + + /* Attempt program update with wrong expected BPF program */ + link_upd_opts.old_prog_fd = bpf_program__fd(skel->progs.egress_alt); + link_upd_opts.flags = BPF_F_REPLACE; + err = bpf_link_update(bpf_link__fd(links[0]), + bpf_program__fd(skel->progs.egress_alt), + &link_upd_opts); + if (CHECK(err == 0 || errno != EPERM, "prog_cmpxchg1", + "unexpectedly succeeded, err %d, errno %d\n", err, -errno)) + goto cleanup; + + /* Compare-exchange single link program from egress to egress_alt */ + link_upd_opts.old_prog_fd = bpf_program__fd(skel->progs.egress); + link_upd_opts.flags = BPF_F_REPLACE; + err = bpf_link_update(bpf_link__fd(links[0]), + bpf_program__fd(skel->progs.egress_alt), + &link_upd_opts); + if (CHECK(err, "prog_cmpxchg2", "errno %d\n", -errno)) + goto cleanup; + + /* ping */ + ping_and_check(0, cg_nr); + + /* close cgroup FDs before detaching links */ + for (i = 0; i < cg_nr; i++) { + if (cgs[i].fd > 0) { + close(cgs[i].fd); + cgs[i].fd = -1; + } + } + + /* BPF programs should still get called */ + ping_and_check(0, cg_nr); + + /* leave cgroup and remove them, don't detach programs */ + cleanup_cgroup_environment(); + + /* BPF programs should have been auto-detached */ + ping_and_check(0, 0); + +cleanup: + if (detach_legacy) + bpf_prog_detach2(prog_fd, cgs[last_cg].fd, + BPF_CGROUP_INET_EGRESS); + + for (i = 0; i < cg_nr; i++) { + if (!IS_ERR(links[i])) + bpf_link__destroy(links[i]); + } + test_cgroup_link__destroy(skel); + + for (i = 0; i < cg_nr; i++) { + if (cgs[i].fd > 0) + close(cgs[i].fd); + } + cleanup_cgroup_environment(); +} diff --git a/tools/testing/selftests/bpf/progs/test_cgroup_link.c b/tools/testing/selftests/bpf/progs/test_cgroup_link.c new file mode 100644 index 000000000000..77e47b9e4446 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_cgroup_link.c @@ -0,0 +1,24 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2020 Facebook +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> + +int calls = 0; +int alt_calls = 0; + +SEC("cgroup_skb/egress1") +int egress(struct __sk_buff *skb) +{ + __sync_fetch_and_add(&calls, 1); + return 1; +} + +SEC("cgroup_skb/egress2") +int egress_alt(struct __sk_buff *skb) +{ + __sync_fetch_and_add(&alt_calls, 1); + return 1; +} + +char _license[] SEC("license") = "GPL"; + |