diff options
| -rw-r--r-- | samples/bpf/Makefile | 2 | ||||
| -rw-r--r-- | samples/bpf/libbpf.c | 21 | ||||
| -rw-r--r-- | samples/bpf/libbpf.h | 3 | ||||
| -rw-r--r-- | samples/bpf/test_cgrp2_attach.c | 147 |
4 files changed, 173 insertions, 0 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index f394ac616ed8..fb17206ddb57 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -22,6 +22,7 @@ hostprogs-y += spintest hostprogs-y += map_perf_test hostprogs-y += test_overhead hostprogs-y += test_cgrp2_array_pin +hostprogs-y += test_cgrp2_attach hostprogs-y += xdp1 hostprogs-y += xdp2 hostprogs-y += test_current_task_under_cgroup @@ -49,6 +50,7 @@ spintest-objs := bpf_load.o libbpf.o spintest_user.o map_perf_test-objs := bpf_load.o libbpf.o map_perf_test_user.o test_overhead-objs := bpf_load.o libbpf.o test_overhead_user.o test_cgrp2_array_pin-objs := libbpf.o test_cgrp2_array_pin.o +test_cgrp2_attach-objs := libbpf.o test_cgrp2_attach.o xdp1-objs := bpf_load.o libbpf.o xdp1_user.o # reuse xdp1 source intentionally xdp2-objs := bpf_load.o libbpf.o xdp1_user.o diff --git a/samples/bpf/libbpf.c b/samples/bpf/libbpf.c index 9969e35550c3..9ce707bf02a7 100644 --- a/samples/bpf/libbpf.c +++ b/samples/bpf/libbpf.c @@ -104,6 +104,27 @@ int bpf_prog_load(enum bpf_prog_type prog_type, return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr)); } +int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type) +{ + union bpf_attr attr = { + .target_fd = target_fd, + .attach_bpf_fd = prog_fd, + .attach_type = type, + }; + + return syscall(__NR_bpf, BPF_PROG_ATTACH, &attr, sizeof(attr)); +} + +int bpf_prog_detach(int target_fd, enum bpf_attach_type type) +{ + union bpf_attr attr = { + .target_fd = target_fd, + .attach_type = type, + }; + + return syscall(__NR_bpf, BPF_PROG_DETACH, &attr, sizeof(attr)); +} + int bpf_obj_pin(int fd, const char *pathname) { union bpf_attr attr = { diff --git a/samples/bpf/libbpf.h b/samples/bpf/libbpf.h index de96a935068d..94a901d86fc2 100644 --- a/samples/bpf/libbpf.h +++ b/samples/bpf/libbpf.h @@ -15,6 +15,9 @@ int bpf_prog_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns, int insn_len, const char *license, int kern_version); +int bpf_prog_attach(int prog_fd, int attachable_fd, enum bpf_attach_type type); +int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type); + int bpf_obj_pin(int fd, const char *pathname); int bpf_obj_get(const char *pathname); diff --git a/samples/bpf/test_cgrp2_attach.c b/samples/bpf/test_cgrp2_attach.c new file mode 100644 index 000000000000..63ef2083f766 --- /dev/null +++ b/samples/bpf/test_cgrp2_attach.c @@ -0,0 +1,147 @@ +/* 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. + * + * - Detaches any eBPF program previously attached to the cgroup + * + * - 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 <stdio.h> +#include <stdlib.h> +#include <stddef.h> +#include <string.h> +#include <unistd.h> +#include <assert.h> +#include <errno.h> +#include <fcntl.h> + +#include <linux/bpf.h> + +#include "libbpf.h" + +enum { + MAP_KEY_PACKETS, + MAP_KEY_BYTES, +}; + +static int prog_load(int map_fd, int verdict) +{ + struct bpf_insn prog[] = { + BPF_MOV64_REG(BPF_REG_6, BPF_REG_1), /* save r6 so it's not clobbered by BPF_CALL */ + + /* Count packets */ + BPF_MOV64_IMM(BPF_REG_0, MAP_KEY_PACKETS), /* r0 = 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), /* load map fd to r1 */ + 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, 1), /* r1 = 1 */ + BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */ + + /* Count bytes */ + BPF_MOV64_IMM(BPF_REG_0, MAP_KEY_BYTES), /* r0 = 1 */ + 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_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6, offsetof(struct __sk_buff, len)), /* r1 = skb->len */ + 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(), + }; + + return bpf_prog_load(BPF_PROG_TYPE_CGROUP_SKB, + prog, sizeof(prog), "GPL", 0); +} + +static int usage(const char *argv0) +{ + printf("Usage: %s <cg-path> <egress|ingress> [drop]\n", argv0); + return EXIT_FAILURE; +} + +int main(int argc, char **argv) +{ + int cg_fd, map_fd, prog_fd, key, ret; + long long pkt_cnt, byte_cnt; + enum bpf_attach_type type; + int verdict = 1; + + if (argc < 3) + return usage(argv[0]); + + if (strcmp(argv[2], "ingress") == 0) + type = BPF_CGROUP_INET_INGRESS; + else if (strcmp(argv[2], "egress") == 0) + type = BPF_CGROUP_INET_EGRESS; + else + return usage(argv[0]); + + if (argc > 3 && strcmp(argv[3], "drop") == 0) + verdict = 0; + + cg_fd = open(argv[1], O_DIRECTORY | O_RDONLY); + if (cg_fd < 0) { + printf("Failed to open cgroup path: '%s'\n", strerror(errno)); + return EXIT_FAILURE; + } + + map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, + sizeof(key), sizeof(byte_cnt), + 256, 0); + if (map_fd < 0) { + printf("Failed to create map: '%s'\n", strerror(errno)); + return EXIT_FAILURE; + } + + prog_fd = prog_load(map_fd, verdict); + printf("Output from kernel verifier:\n%s\n-------\n", bpf_log_buf); + + if (prog_fd < 0) { + printf("Failed to load prog: '%s'\n", strerror(errno)); + return EXIT_FAILURE; + } + + ret = bpf_prog_detach(cg_fd, type); + printf("bpf_prog_detach() returned '%s' (%d)\n", strerror(errno), errno); + + ret = bpf_prog_attach(prog_fd, cg_fd, type); + if (ret < 0) { + printf("Failed to attach prog to cgroup: '%s'\n", + strerror(errno)); + return EXIT_FAILURE; + } + + while (1) { + key = MAP_KEY_PACKETS; + assert(bpf_lookup_elem(map_fd, &key, &pkt_cnt) == 0); + + key = MAP_KEY_BYTES; + assert(bpf_lookup_elem(map_fd, &key, &byte_cnt) == 0); + + printf("cgroup received %lld packets, %lld bytes\n", + pkt_cnt, byte_cnt); + sleep(1); + } + + return EXIT_SUCCESS; +} |