/* eBPF example program: * * - Creates arraymap in kernel with 4 bytes keys and 8 byte values * * - Loads eBPF program * * The eBPF program accesses the map passed in to store two pieces of * information. The number of invocations of the program, which maps * to the number of packets received, is stored to key 0. Key 1 is * incremented on each iteration by the number of bytes stored in * the skb. * * - Attaches the new program to a cgroup using BPF_PROG_ATTACH * * - Every second, reads map[0] and map[1] to see how many bytes and * packets were seen on any socket of tasks in the given cgroup. */ #define _GNU_SOURCE #include #include #include #include #include #include "libbpf.h" #include "cgroup_helpers.h" #define FOO "/foo" #define BAR "/foo/bar/" #define PING_CMD "ping -c1 -w1 127.0.0.1 > /dev/null" char bpf_log_buf[BPF_LOG_BUF_SIZE]; static int prog_load(int verdict) { int ret; struct bpf_insn prog[] = { BPF_MOV64_IMM(BPF_REG_0, verdict), /* r0 = verdict */ BPF_EXIT_INSN(), }; size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn); ret = bpf_load_program(BPF_PROG_TYPE_CGROUP_SKB, prog, insns_cnt, "GPL", 0, bpf_log_buf, BPF_LOG_BUF_SIZE); if (ret < 0) { log_err("Loading program"); printf("Output from verifier:\n%s\n-------\n", bpf_log_buf); return 0; } return ret; } static int test_foo_bar(void) { int drop_prog, allow_prog, foo = 0, bar = 0, rc = 0; allow_prog = prog_load(1); if (!allow_prog) goto err; drop_prog = prog_load(0); if (!drop_prog) goto err; if (setup_cgroup_environment()) goto err; /* Create cgroup /foo, get fd, and join it */ foo = create_and_get_cgroup(FOO); if (!foo) goto err; if (join_cgroup(FOO)) goto err; if (bpf_prog_attach(drop_prog, foo, BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_OVERRIDE)) { log_err("Attaching prog to /foo"); goto err; } printf("Attached DROP prog. This ping in cgroup /foo should fail...\n"); assert(system(PING_CMD) != 0); /* Create cgroup /foo/bar, get fd, and join it */ bar = create_and_get_cgroup(BAR); if (!bar) goto err; if (join_cgroup(BAR)) goto err; printf("Attached DROP prog. This ping in cgroup /foo/bar should fail...\n"); assert(system(PING_CMD) != 0); if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_OVERRIDE)) { log_err("Attaching prog to /foo/bar"); goto err; } printf("Attached PASS prog. This ping in cgroup /foo/bar should pass...\n"); assert(system(PING_CMD) == 0); if (bpf_prog_detach(bar, BPF_CGROUP_INET_EGRESS)) { log_err("Detaching program from /foo/bar"); goto err; } printf("Detached PASS from /foo/bar while DROP is attached to /foo.\n" "This ping in cgroup /foo/bar should fail...\n"); assert(system(PING_CMD) != 0); if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_OVERRIDE)) { log_err("Attaching prog to /foo/bar"); goto err; } if (bpf_prog_detach(foo, BPF_CGROUP_INET_EGRESS)) { log_err("Detaching program from /foo"); goto err; } printf("Attached PASS from /foo/bar and detached DROP from /foo.\n" "This ping in cgroup /foo/bar should pass...\n"); assert(system(PING_CMD) == 0); if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_OVERRIDE)) { log_err("Attaching prog to /foo/bar"); goto err; } if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 0)) { errno = 0; log_err("Unexpected success attaching prog to /foo/bar"); goto err; } if (bpf_prog_detach(bar, BPF_CGROUP_INET_EGRESS)) { log_err("Detaching program from /foo/bar"); goto err; } if (!bpf_prog_detach(foo, BPF_CGROUP_INET_EGRESS)) { errno = 0; log_err("Unexpected success in double detach from /foo"); goto err; } if (bpf_prog_attach(allow_prog, foo, BPF_CGROUP_INET_EGRESS, 0)) { log_err("Attaching non-overridable prog to /foo"); goto err; } if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 0)) { errno = 0; log_err("Unexpected success attaching non-overridable prog to /foo/bar"); goto err; } if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_OVERRIDE)) { errno = 0; log_err("Unexpected success attaching overridable prog to /foo/bar"); goto err; } if (!bpf_prog_attach(allow_prog, foo, BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_OVERRIDE)) { errno = 0; log_err("Unexpected success attaching overridable prog to /foo"); goto err; } if (bpf_prog_attach(drop_prog, foo, BPF_CGROUP_INET_EGRESS, 0)) { log_err("Attaching different non-overridable prog to /foo"); goto err; } goto out; err: rc = 1; out: close(foo); close(bar); cleanup_cgroup_environment(); if (!rc) printf("### override:PASS\n"); else printf("### override:FAIL\n"); return rc; } static int map_fd = -1; static int prog_load_cnt(int verdict, int val) { if (map_fd < 0) map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, 4, 8, 1, 0); if (map_fd < 0) { printf("failed to create map '%s'\n", strerror(errno)); return -1; } struct bpf_insn prog[] = { BPF_MOV32_IMM(BPF_REG_0, 0), BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */ BPF_LD_MAP_FD(BPF_REG_1, map_fd), BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), BPF_MOV64_IMM(BPF_REG_1, val), /* r1 = 1 */ BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */ BPF_MOV64_IMM(BPF_REG_0, verdict), /* r0 = verdict */ BPF_EXIT_INSN(), }; size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn); int ret; ret = bpf_load_program(BPF_PROG_TYPE_CGROUP_SKB, prog, insns_cnt, "GPL", 0, bpf_log_buf, BPF_LOG_BUF_SIZE); if (ret < 0) { log_err("Loading program"); printf("Output from verifier:\n%s\n-------\n", bpf_log_buf); return 0; } return ret; } static int test_multiprog(void) { __u32 prog_ids[4], prog_cnt = 0, attach_flags, saved_prog_id; int cg1 = 0, cg2 = 0, cg3 = 0, cg4 = 0, cg5 = 0, key = 0; int drop_prog, allow_prog[6] = {}, rc = 0; unsigned long long value; int i = 0; for (i = 0; i < 6; i++) { allow_prog[i] = prog_load_cnt(1, 1 << i); if (!allow_prog[i]) goto err; } drop_prog = prog_load_cnt(0, 1); if (!drop_prog) goto err; if (setup_cgroup_environment()) goto err; cg1 = create_and_get_cgroup("/cg1"); if (!cg1) goto err; cg2 = create_and_get_cgroup("/cg1/cg2"); if (!cg2) goto err; cg3 = create_and_get_cgroup("/cg1/cg2/cg3"); if (!cg3) goto err; cg4 = create_and_get_cgroup("/cg1/cg2/cg3/cg4"); if (!cg4) goto err; cg5 = create_and_get_cgroup("/cg1/cg2/cg3/cg4/cg5"); if (!cg5) goto err; if (join_cgroup("/cg1/cg2/cg3/cg4/cg5")) goto err; if (bpf_prog_attach(allow_prog[0], cg1, BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_MULTI)) { log_err("Attaching prog to cg1"); goto err; } if (!bpf_prog_attach(allow_prog[0], cg1, BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_MULTI)) { log_err("Unexpected success attaching the same prog to cg1"); goto err; } if (bpf_prog_attach(allow_prog[1], cg1, BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_MULTI)) { log_err("Attaching prog2 to cg1"); goto err; } if (bpf_prog_attach(allow_prog[2], cg2, BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_OVERRIDE)) { log_err("Attaching prog to cg2"); goto err; } if (bpf_prog_attach(allow_prog[3], cg3, BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_MULTI)) { log_err("Attaching prog to cg3"); goto err; } if (bpf_prog_attach(allow_prog[4], cg4, BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_OVERRIDE)) { log_err("Attaching prog to cg4"); goto err; } if (bpf_prog_attach(allow_prog[5], cg5, BPF_CGROUP_INET_EGRESS, 0)) { log_err("Attaching prog to cg5"); goto err; } assert(system(PING_CMD) == 0); assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0); assert(value == 1 + 2 + 8 + 32); /* query the number of effective progs in cg5 */ assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, BPF_F_QUERY_EFFECTIVE, NULL, NULL, &prog_cnt) == 0); assert(prog_cnt == 4); /* retrieve prog_ids of effective progs in cg5 */ assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, BPF_F_QUERY_EFFECTIVE, &attach_flags, prog_ids, &prog_cnt) == 0); assert(prog_cnt == 4); assert(attach_flags == 0); saved_prog_id = prog_ids[0]; /* check enospc handling */ prog_ids[0] = 0; prog_cnt = 2; assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, BPF_F_QUERY_EFFECTIVE, &attach_flags, prog_ids, &prog_cnt) == -1 && errno == ENOSPC); assert(prog_cnt == 4); /* check that prog_ids are returned even when buffer is too small */ assert(prog_ids[0] == saved_prog_id); /* retrieve prog_id of single attached prog in cg5 */ prog_ids[0] = 0; assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, 0, NULL, prog_ids, &prog_cnt) == 0); assert(prog_cnt == 1); assert(prog_ids[0] == saved_prog_id); /* detach bottom program and ping again */ if (bpf_prog_detach2(-1, cg5, BPF_CGROUP_INET_EGRESS)) { log_err("Detaching prog from cg5"); goto err; } value = 0; assert(bpf_map_update_elem(map_fd, &key, &value, 0) == 0); assert(system(PING_CMD) == 0); assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0); assert(value == 1 + 2 + 8 + 16); /* detach 3rd from bottom program and ping again */ errno = 0; if (!bpf_prog_detach2(0, cg3, BPF_CGROUP_INET_EGRESS)) { log_err("Unexpected success on detach from cg3"); goto err; } if (bpf_prog_detach2(allow_prog[3], cg3, BPF_CGROUP_INET_EGRESS)) { log_err("Detaching from cg3"); goto err; } value = 0; assert(bpf_map_update_elem(map_fd, &key, &value, 0) == 0); assert(system(PING_CMD) == 0); assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0); assert(value == 1 + 2 + 16); /* detach 2nd from bottom program and ping again */ if (bpf_prog_detach2(-1, cg4, BPF_CGROUP_INET_EGRESS)) { log_err("Detaching prog from cg4"); goto err; } value = 0; assert(bpf_map_update_elem(map_fd, &key, &value, 0) == 0); assert(system(PING_CMD) == 0); assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0); assert(value == 1 + 2 + 4); prog_cnt = 4; assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, BPF_F_QUERY_EFFECTIVE, &attach_flags, prog_ids, &prog_cnt) == 0); assert(prog_cnt == 3); assert(attach_flags == 0); assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, 0, NULL, prog_ids, &prog_cnt) == 0); assert(prog_cnt == 0); goto out; err: rc = 1; out: for (i = 0; i < 6; i++) if (allow_prog[i] > 0) close(allow_prog[i]); close(cg1); close(cg2); close(cg3); close(cg4); close(cg5); cleanup_cgroup_environment(); if (!rc) printf("### multi:PASS\n"); else printf("### multi:FAIL\n"); return rc; } int main(int argc, char **argv) { int rc = 0; rc = test_foo_bar(); if (rc) return rc; return test_multiprog(); }