1 /* eBPF example program:
5 * The eBPF program sets the sk_bound_dev_if index in new AF_INET{6}
6 * sockets opened by processes in the cgroup.
8 * - Attaches the new program to a cgroup using BPF_PROG_ATTACH
22 #include <linux/bpf.h>
26 char bpf_log_buf
[BPF_LOG_BUF_SIZE
];
28 static int prog_load(int idx
)
30 struct bpf_insn prog
[] = {
31 BPF_MOV64_REG(BPF_REG_6
, BPF_REG_1
),
32 BPF_MOV64_IMM(BPF_REG_3
, idx
),
33 BPF_MOV64_IMM(BPF_REG_2
, offsetof(struct bpf_sock
, bound_dev_if
)),
34 BPF_STX_MEM(BPF_W
, BPF_REG_1
, BPF_REG_3
, offsetof(struct bpf_sock
, bound_dev_if
)),
35 BPF_MOV64_IMM(BPF_REG_0
, 1), /* r0 = verdict */
38 size_t insns_cnt
= sizeof(prog
) / sizeof(struct bpf_insn
);
40 return bpf_load_program(BPF_PROG_TYPE_CGROUP_SOCK
, prog
, insns_cnt
,
41 "GPL", 0, bpf_log_buf
, BPF_LOG_BUF_SIZE
);
44 static int usage(const char *argv0
)
46 printf("Usage: %s cg-path device-index\n", argv0
);
50 int main(int argc
, char **argv
)
52 int cg_fd
, prog_fd
, ret
;
56 return usage(argv
[0]);
58 idx
= if_nametoindex(argv
[2]);
60 printf("Invalid device name\n");
64 cg_fd
= open(argv
[1], O_DIRECTORY
| O_RDONLY
);
66 printf("Failed to open cgroup path: '%s'\n", strerror(errno
));
70 prog_fd
= prog_load(idx
);
71 printf("Output from kernel verifier:\n%s\n-------\n", bpf_log_buf
);
74 printf("Failed to load prog: '%s'\n", strerror(errno
));
78 ret
= bpf_prog_attach(prog_fd
, cg_fd
, BPF_CGROUP_INET_SOCK_CREATE
);
80 printf("Failed to attach prog to cgroup: '%s'\n",