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// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <linux/filter.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "bpf_rlimit.h"
#include "bpf_util.h"
#include "cgroup_helpers.h"
#define CG_PATH "/sockopt"
#define SOL_CUSTOM 0xdeadbeef
static int getsetsockopt(void)
{
int fd, err;
union {
char u8[4];
__u32 u32;
} buf = {};
socklen_t optlen;
fd = socket(AF_INET, SOCK_STREAM, 0);
if (fd < 0) {
log_err("Failed to create socket");
return -1;
}
/* IP_TOS - BPF bypass */
buf.u8[0] = 0x08;
err = setsockopt(fd, SOL_IP, IP_TOS, &buf, 1);
if (err) {
log_err("Failed to call setsockopt(IP_TOS)");
goto err;
}
buf.u8[0] = 0x00;
optlen = 1;
err = getsockopt(fd, SOL_IP, IP_TOS, &buf, &optlen);
if (err) {
log_err("Failed to call getsockopt(IP_TOS)");
goto err;
}
if (buf.u8[0] != 0x08) {
log_err("Unexpected getsockopt(IP_TOS) buf[0] 0x%02x != 0x08",
buf.u8[0]);
goto err;
}
/* IP_TTL - EPERM */
buf.u8[0] = 1;
err = setsockopt(fd, SOL_IP, IP_TTL, &buf, 1);
if (!err || errno != EPERM) {
log_err("Unexpected success from setsockopt(IP_TTL)");
goto err;
}
/* SOL_CUSTOM - handled by BPF */
buf.u8[0] = 0x01;
err = setsockopt(fd, SOL_CUSTOM, 0, &buf, 1);
if (err) {
log_err("Failed to call setsockopt");
goto err;
}
buf.u32 = 0x00;
optlen = 4;
err = getsockopt(fd, SOL_CUSTOM, 0, &buf, &optlen);
if (err) {
log_err("Failed to call getsockopt");
goto err;
}
if (optlen != 1) {
log_err("Unexpected optlen %d != 1", optlen);
goto err;
}
if (buf.u8[0] != 0x01) {
log_err("Unexpected buf[0] 0x%02x != 0x01", buf.u8[0]);
goto err;
}
/* SO_SNDBUF is overwritten */
buf.u32 = 0x01010101;
err = setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &buf, 4);
if (err) {
log_err("Failed to call setsockopt(SO_SNDBUF)");
goto err;
}
buf.u32 = 0x00;
optlen = 4;
err = getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &buf, &optlen);
if (err) {
log_err("Failed to call getsockopt(SO_SNDBUF)");
goto err;
}
if (buf.u32 != 0x55AA*2) {
log_err("Unexpected getsockopt(SO_SNDBUF) 0x%x != 0x55AA*2",
buf.u32);
goto err;
}
close(fd);
return 0;
err:
close(fd);
return -1;
}
static int prog_attach(struct bpf_object *obj, int cgroup_fd, const char *title)
{
enum bpf_attach_type attach_type;
enum bpf_prog_type prog_type;
struct bpf_program *prog;
int err;
err = libbpf_prog_type_by_name(title, &prog_type, &attach_type);
if (err) {
log_err("Failed to deduct types for %s BPF program", title);
return -1;
}
prog = bpf_object__find_program_by_title(obj, title);
if (!prog) {
log_err("Failed to find %s BPF program", title);
return -1;
}
err = bpf_prog_attach(bpf_program__fd(prog), cgroup_fd,
attach_type, 0);
if (err) {
log_err("Failed to attach %s BPF program", title);
return -1;
}
return 0;
}
static int run_test(int cgroup_fd)
{
struct bpf_prog_load_attr attr = {
.file = "./sockopt_sk.o",
};
struct bpf_object *obj;
int ignored;
int err;
err = bpf_prog_load_xattr(&attr, &obj, &ignored);
if (err) {
log_err("Failed to load BPF object");
return -1;
}
err = prog_attach(obj, cgroup_fd, "cgroup/getsockopt");
if (err)
goto close_bpf_object;
err = prog_attach(obj, cgroup_fd, "cgroup/setsockopt");
if (err)
goto close_bpf_object;
err = getsetsockopt();
close_bpf_object:
bpf_object__close(obj);
return err;
}
int main(int args, char **argv)
{
int cgroup_fd;
int err = EXIT_SUCCESS;
if (setup_cgroup_environment())
goto cleanup_obj;
cgroup_fd = create_and_get_cgroup(CG_PATH);
if (cgroup_fd < 0)
goto cleanup_cgroup_env;
if (join_cgroup(CG_PATH))
goto cleanup_cgroup;
if (run_test(cgroup_fd))
err = EXIT_FAILURE;
printf("test_sockopt_sk: %s\n",
err == EXIT_SUCCESS ? "PASSED" : "FAILED");
cleanup_cgroup:
close(cgroup_fd);
cleanup_cgroup_env:
cleanup_cgroup_environment();
cleanup_obj:
return err;
}
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