// SPDX-License-Identifier: GPL-2.0
#include <unistd.h>
#include <test_progs.h>
#include <network_helpers.h>
#include "tailcall_poke.skel.h"
/* test_tailcall_1 checks basic functionality by patching multiple locations
* in a single program for a single tail call slot with nop->jmp, jmp->nop
* and jmp->jmp rewrites. Also checks for nop->nop.
*/
static void test_tailcall_1(void)
{
int err, map_fd, prog_fd, main_fd, i, j;
struct bpf_map *prog_array;
struct bpf_program *prog;
struct bpf_object *obj;
char prog_name[32];
char buff[128] = {};
LIBBPF_OPTS(bpf_test_run_opts, topts,
.data_in = buff,
.data_size_in = sizeof(buff),
.repeat = 1,
);
err = bpf_prog_test_load("tailcall1.bpf.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
&prog_fd);
if (CHECK_FAIL(err))
return;
prog = bpf_object__find_program_by_name(obj, "entry");
if (CHECK_FAIL(!prog))
goto out;
main_fd = bpf_program__fd(prog);
if (CHECK_FAIL(main_fd < 0))
goto out;
prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
if (CHECK_FAIL(!prog_array))
goto out;
map_fd = bpf_map__fd(prog_array);
if (CHECK_FAIL(map_fd < 0))
goto out;
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
prog = bpf_object__find_program_by_name(obj, prog_name);
if (CHECK_FAIL(!prog))
goto out;
prog_fd = bpf_program__fd(prog);
if (CHECK_FAIL(prog_fd < 0))
goto out;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
}
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, i, "tailcall retval");
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err))
goto out;
}
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, 3, "tailcall retval");
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
prog = bpf_object__find_program_by_name(obj, prog_name);
if (CHECK_FAIL(!prog))
goto out;
prog_fd = bpf_program__fd(prog);
if (CHECK_FAIL(prog_fd < 0))
goto out;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
}
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_OK(topts.retval, "tailcall retval");
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
j = bpf_map__max_entries(prog_array) - 1 - i;
snprintf(prog_name, sizeof(prog_name), "classifier_%d", j);
prog = bpf_object__find_program_by_name(obj, prog_name);
if (CHECK_FAIL(!prog))
goto out;
prog_fd = bpf_program__fd(prog);
if (CHECK_FAIL(prog_fd < 0))
goto out;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
}
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
j = bpf_map__max_entries(prog_array) - 1 - i;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, j, "tailcall retval");
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err))
goto out;
}
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, 3, "tailcall retval");
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err >= 0 || errno != ENOENT))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, 3, "tailcall retval");
}
out:
bpf_object__close(obj);
}
/* test_tailcall_2 checks that patching multiple programs for a single
* tail call slot works. It also jumps through several programs and tests
* the tail call limit counter.
*/
static void test_tailcall_2(void)
{
int err, map_fd, prog_fd, main_fd, i;
struct bpf_map *prog_array;
struct bpf_program *prog;
struct bpf_object *obj;
char prog_name[32];
char buff[128] = {};
LIBBPF_OPTS(bpf_test_run_opts, topts,
.data_in = buff,
.data_size_in = sizeof(buff),
.repeat = 1,
);
err = bpf_prog_test_load("tailcall2.bpf.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
&prog_fd);
if (CHECK_FAIL(err))
return;
prog = bpf_object__find_program_by_name(obj, "entry");
if (CHECK_FAIL(!prog))
goto out;
main_fd = bpf_program__fd(prog);
if (CHECK_FAIL(main_fd < 0))
goto out;
prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
if (CHECK_FAIL(!prog_array))
goto out;
map_fd = bpf_map__fd(prog_array);
if (CHECK_FAIL(map_fd < 0))
goto out;
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
prog = bpf_object__find_program_by_name(obj, prog_name);
if (CHECK_FAIL(!prog))
goto out;
prog_fd = bpf_program__fd(prog);
if (CHECK_FAIL(prog_fd < 0))
goto out;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
}
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, 2, "tailcall retval");
i = 2;
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, 1, "tailcall retval");
i = 0;
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, 3, "tailcall retval");
out:
bpf_object__close(obj);
}
static void test_tailcall_count(const char *which, bool test_fentry,
bool test_fexit)
{
struct bpf_object *obj = NULL, *fentry_obj = NULL, *fexit_obj = NULL;
struct bpf_link *fentry_link = NULL, *fexit_link = NULL;
int err, map_fd, prog_fd, main_fd, data_fd, i, val;
struct bpf_map *prog_array, *data_map;
struct bpf_program *prog;
char buff[128] = {};
LIBBPF_OPTS(bpf_test_run_opts, topts,
.data_in = buff,
.data_size_in = sizeof(buff),
.repeat = 1,
);
err = bpf_prog_test_load(which, BPF_PROG_TYPE_SCHED_CLS, &obj,
&prog_fd);
if (CHECK_FAIL(err))
return;
prog = bpf_object__find_program_by_name(obj, "entry");
if (CHECK_FAIL(!prog))
goto out;
main_fd = bpf_program__fd(prog);
if (CHECK_FAIL(main_fd < 0))
goto out;
prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
if (CHECK_FAIL(!prog_array))
goto out;
map_fd = bpf_map__fd(prog_array);
if (CHECK_FAIL(map_fd < 0))
goto out;
prog = bpf_object__find_program_by_name(obj, "classifier_0");
if (CHECK_FAIL(!prog))
goto out;
prog_fd = bpf_program__fd(prog);
if (CHECK_FAIL(prog_fd < 0))
goto out;
i = 0;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
if (test_fentry) {
fentry_obj = bpf_object__open_file("tailcall_bpf2bpf_fentry.bpf.o",
NULL);
if (!ASSERT_OK_PTR(fentry_obj, "open fentry_obj file"))
goto out;
prog = bpf_object__find_program_by_name(fentry_obj, "fentry");
if (!ASSERT_OK_PTR(prog, "find fentry prog"))
goto out;
err = bpf_program__set_attach_target(prog, prog_fd,
"subprog_tail");
if (!ASSERT_OK(err, "set_attach_target subprog_tail"))
goto out;
err = bpf_object__load(fentry_obj);
if (!ASSERT_OK(err, "load fentry_obj"))
goto out;
fentry_link = bpf_program__attach_trace(prog);
if (!ASSERT_OK_PTR(fentry_link, "attach_trace"))
goto out;
}
if (test_fexit) {
fexit_obj = bpf_object__open_file("tailcall_bpf2bpf_fexit.bpf.o",
NULL);
if (!ASSERT_OK_PTR(fexit_obj, "open fexit_obj file"))
goto out;
prog = bpf_object__find_program_by_name(fexit_obj, "fexit");
if (!ASSERT_OK_PTR(prog, "find fexit prog"))
goto out;
err = bpf_program__set_attach_target(prog, prog_fd,
"subprog_tail");
if (!ASSERT_OK(err, "set_attach_target subprog_tail"))
goto out;
err = bpf_object__load(fexit_obj);
if (!ASSERT_OK(err, "load fexit_obj"))
goto out;
fexit_link = bpf_program__attach_trace(prog);
if (!ASSERT_OK_PTR(fexit_link, "attach_trace"))
goto out;
}
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, 1, "tailcall retval");
data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
goto out;
data_fd = bpf_map__fd(data_map);
if (CHECK_FAIL(data_fd < 0))
goto out;
i = 0;
err = bpf_map_lookup_elem(data_fd, &i, &val);
ASSERT_OK(err, "tailcall count");
ASSERT_EQ(val, 33, "tailcall count");
if (test_fentry) {
data_map = bpf_object__find_map_by_name(fentry_obj, ".bss");
if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
"find tailcall_bpf2bpf_fentry.bss map"))
goto out;
data_fd = bpf_map__fd(data_map);
if (!ASSERT_FALSE(data_fd < 0,
"find tailcall_bpf2bpf_fentry.bss map fd"))
goto out;
i = 0;
err = bpf_map_lookup_elem(data_fd, &i, &val);
ASSERT_OK(err, "fentry count");
ASSERT_EQ(val, 33, "fentry count");
}
if (test_fexit) {
data_map = bpf_object__find_map_by_name(fexit_obj, ".bss");
if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
"find tailcall_bpf2bpf_fexit.bss map"))
goto out;
data_fd = bpf_map__fd(data_map);
if (!ASSERT_FALSE(data_fd < 0,
"find tailcall_bpf2bpf_fexit.bss map fd"))
goto out;
i = 0;
err = bpf_map_lookup_elem(data_fd, &i, &val);
ASSERT_OK(err, "fexit count");
ASSERT_EQ(val, 33, "fexit count");
}
i = 0;
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_OK(topts.retval, "tailcall retval");
out:
bpf_link__destroy(fentry_link);
bpf_link__destroy(fexit_link);
bpf_object__close(fentry_obj);
bpf_object__close(fexit_obj);
bpf_object__close(obj);
}
/* test_tailcall_3 checks that the count value of the tail call limit
* enforcement matches with expectations. JIT uses direct jump.
*/
static void test_tailcall_3(void)
{
test_tailcall_count("tailcall3.bpf.o", false, false);
}
/* test_tailcall_6 checks that the count value of the tail call limit
* enforcement matches with expectations. JIT uses indirect jump.
*/
static void test_tailcall_6(void)
{
test_tailcall_count("tailcall6.bpf.o", false, false);
}
/* test_tailcall_4 checks that the kernel properly selects indirect jump
* for the case where the key is not known. Latter is passed via global
* data to select different targets we can compare return value of.
*/
static void test_tailcall_4(void)
{
int err, map_fd, prog_fd, main_fd, data_fd, i;
struct bpf_map *prog_array, *data_map;
struct bpf_program *prog;
struct bpf_object *obj;
static const int zero = 0;
char buff[128] = {};
char prog_name[32];
LIBBPF_OPTS(bpf_test_run_opts, topts,
.data_in = buff,
.data_size_in = sizeof(buff),
.repeat = 1,
);
err = bpf_prog_test_load("tailcall4.bpf.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
&prog_fd);
if (CHECK_FAIL(err))
return;
prog = bpf_object__find_program_by_name(obj, "entry");
if (CHECK_FAIL(!prog))
goto out;
main_fd = bpf_program__fd(prog);
if (CHECK_FAIL(main_fd < 0))
goto out;
prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
if (CHECK_FAIL(!prog_array))
goto out;
map_fd = bpf_map__fd(prog_array);
if (CHECK_FAIL(map_fd < 0))
goto out;
data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
goto out;
data_fd = bpf_map__fd(data_map);
if (CHECK_FAIL(data_fd < 0))
goto out;
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
prog = bpf_object__find_program_by_name(obj, prog_name);
if (CHECK_FAIL(!prog))
goto out;
prog_fd = bpf_program__fd(prog);
if (CHECK_FAIL(prog_fd < 0))
goto out;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
}
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
err = bpf_map_update_elem(data_fd, &zero, &i, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, i, "tailcall retval");
}
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
err = bpf_map_update_elem(data_fd, &zero, &i, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, 3, "tailcall retval");
}
out:
bpf_object__close(obj);
}
/* test_tailcall_5 probes similarly to test_tailcall_4 that the kernel generates
* an indirect jump when the keys are const but different from different branches.
*/
static void test_tailcall_5(void)
{
int err, map_fd, prog_fd, main_fd, data_fd, i, key[] = { 1111, 1234, 5678 };
struct bpf_map *prog_array, *data_map;
struct bpf_program *prog;
struct bpf_object *obj;
static const int zero = 0;
char buff[128] = {};
char prog_name[32];
LIBBPF_OPTS(bpf_test_run_opts, topts,
.data_in = buff,
.data_size_in = sizeof(buff),
.repeat = 1,
);
err = bpf_prog_test_load("tailcall5.bpf.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
&prog_fd);
if (CHECK_FAIL(err))
return;
prog = bpf_object__find_program_by_name(obj, "entry");
if (CHECK_FAIL(!prog))
goto out;
main_fd = bpf_program__fd(prog);
if (CHECK_FAIL(main_fd < 0))
goto out;
prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
if (CHECK_FAIL(!prog_array))
goto out;
map_fd = bpf_map__fd(prog_array);
if (CHECK_FAIL(map_fd < 0))
goto out;
data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
goto out;
data_fd = bpf_map__fd(data_map);
if (CHECK_FAIL(data_fd < 0))
goto out;
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
prog = bpf_object__find_program_by_name(obj, prog_name);
if (CHECK_FAIL(!prog))
goto out;
prog_fd = bpf_program__fd(prog);
if (CHECK_FAIL(prog_fd < 0))
goto out;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
}
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
err = bpf_map_update_elem(data_fd, &zero, &key[i], BPF_ANY);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, i, "tailcall retval");
}
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
err = bpf_map_update_elem(data_fd, &zero, &key[i], BPF_ANY);
if (CHECK_FAIL(err))
goto out;
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, 3, "tailcall retval");
}
out:
bpf_object__close(obj);
}
/* test_tailcall_bpf2bpf_1 purpose is to make sure that tailcalls are working
* correctly in correlation with BPF subprograms
*/
static void test_tailcall_bpf2bpf_1(void)
{
int err, map_fd, prog_fd, main_fd, i;
struct bpf_map *prog_array;
struct bpf_program *prog;
struct bpf_object *obj;
char prog_name[32];
LIBBPF_OPTS(bpf_test_run_opts, topts,
.data_in = &pkt_v4,
.data_size_in = sizeof(pkt_v4),
.repeat = 1,
);
err = bpf_prog_test_load("tailcall_bpf2bpf1.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
&obj, &prog_fd);
if (CHECK_FAIL(err))
return;
prog = bpf_object__find_program_by_name(obj, "entry");
if (CHECK_FAIL(!prog))
goto out;
main_fd = bpf_program__fd(prog);
if (CHECK_FAIL(main_fd < 0))
goto out;
prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
if (CHECK_FAIL(!prog_array))
goto out;
map_fd = bpf_map__fd(prog_array);
if (CHECK_FAIL(map_fd < 0))
goto out;
/* nop -> jmp */
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
prog = bpf_object__find_program_by_name(obj, prog_name);
if (CHECK_FAIL(!prog))
goto out;
prog_fd = bpf_program__fd(prog);
if (CHECK_FAIL(prog_fd < 0))
goto out;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
}
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, 1, "tailcall retval");
/* jmp -> nop, call subprog that will do tailcall */
i = 1;
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_OK(topts.retval, "tailcall retval");
/* make sure that subprog can access ctx and entry prog that
* called this subprog can properly return
*/
i = 0;
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, sizeof(pkt_v4) * 2, "tailcall retval");
out:
bpf_object__close(obj);
}
/* test_tailcall_bpf2bpf_2 checks that the count value of the tail call limit
* enforcement matches with expectations when tailcall is preceded with
* bpf2bpf call.
*/
static void test_tailcall_bpf2bpf_2(void)
{
int err, map_fd, prog_fd, main_fd, data_fd, i, val;
struct bpf_map *prog_array, *data_map;
struct bpf_program *prog;
struct bpf_object *obj;
char buff[128] = {};
LIBBPF_OPTS(bpf_test_run_opts, topts,
.data_in = buff,
.data_size_in = sizeof(buff),
.repeat = 1,
);
err = bpf_prog_test_load("tailcall_bpf2bpf2.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
&obj, &prog_fd);
if (CHECK_FAIL(err))
return;
prog = bpf_object__find_program_by_name(obj, "entry");
if (CHECK_FAIL(!prog))
goto out;
main_fd = bpf_program__fd(prog);
if (CHECK_FAIL(main_fd < 0))
goto out;
prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
if (CHECK_FAIL(!prog_array))
goto out;
map_fd = bpf_map__fd(prog_array);
if (CHECK_FAIL(map_fd < 0))
goto out;
prog = bpf_object__find_program_by_name(obj, "classifier_0");
if (CHECK_FAIL(!prog))
goto out;
prog_fd = bpf_program__fd(prog);
if (CHECK_FAIL(prog_fd < 0))
goto out;
i = 0;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, 1, "tailcall retval");
data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
goto out;
data_fd = bpf_map__fd(data_map);
if (CHECK_FAIL(data_fd < 0))
goto out;
i = 0;
err = bpf_map_lookup_elem(data_fd, &i, &val);
ASSERT_OK(err, "tailcall count");
ASSERT_EQ(val, 33, "tailcall count");
i = 0;
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_OK(topts.retval, "tailcall retval");
out:
bpf_object__close(obj);
}
/* test_tailcall_bpf2bpf_3 checks that non-trivial amount of stack (up to
* 256 bytes) can be used within bpf subprograms that have the tailcalls
* in them
*/
static void test_tailcall_bpf2bpf_3(void)
{
int err, map_fd, prog_fd, main_fd, i;
struct bpf_map *prog_array;
struct bpf_program *prog;
struct bpf_object *obj;
char prog_name[32];
LIBBPF_OPTS(bpf_test_run_opts, topts,
.data_in = &pkt_v4,
.data_size_in = sizeof(pkt_v4),
.repeat = 1,
);
err = bpf_prog_test_load("tailcall_bpf2bpf3.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
&obj, &prog_fd);
if (CHECK_FAIL(err))
return;
prog = bpf_object__find_program_by_name(obj, "entry");
if (CHECK_FAIL(!prog))
goto out;
main_fd = bpf_program__fd(prog);
if (CHECK_FAIL(main_fd < 0))
goto out;
prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
if (CHECK_FAIL(!prog_array))
goto out;
map_fd = bpf_map__fd(prog_array);
if (CHECK_FAIL(map_fd < 0))
goto out;
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
prog = bpf_object__find_program_by_name(obj, prog_name);
if (CHECK_FAIL(!prog))
goto out;
prog_fd = bpf_program__fd(prog);
if (CHECK_FAIL(prog_fd < 0))
goto out;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
}
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, sizeof(pkt_v4) * 3, "tailcall retval");
i = 1;
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, sizeof(pkt_v4), "tailcall retval");
i = 0;
err = bpf_map_delete_elem(map_fd, &i);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, sizeof(pkt_v4) * 2, "tailcall retval");
out:
bpf_object__close(obj);
}
#include "tailcall_bpf2bpf4.skel.h"
/* test_tailcall_bpf2bpf_4 checks that tailcall counter is correctly preserved
* across tailcalls combined with bpf2bpf calls. for making sure that tailcall
* counter behaves correctly, bpf program will go through following flow:
*
* entry -> entry_subprog -> tailcall0 -> bpf_func0 -> subprog0 ->
* -> tailcall1 -> bpf_func1 -> subprog1 -> tailcall2 -> bpf_func2 ->
* subprog2 [here bump global counter] --------^
*
* We go through first two tailcalls and start counting from the subprog2 where
* the loop begins. At the end of the test make sure that the global counter is
* equal to 31, because tailcall counter includes the first two tailcalls
* whereas global counter is incremented only on loop presented on flow above.
*
* The noise parameter is used to insert bpf_map_update calls into the logic
* to force verifier to patch instructions. This allows us to ensure jump
* logic remains correct with instruction movement.
*/
static void test_tailcall_bpf2bpf_4(bool noise)
{
int err, map_fd, prog_fd, main_fd, data_fd, i;
struct tailcall_bpf2bpf4__bss val;
struct bpf_map *prog_array, *data_map;
struct bpf_program *prog;
struct bpf_object *obj;
char prog_name[32];
LIBBPF_OPTS(bpf_test_run_opts, topts,
.data_in = &pkt_v4,
.data_size_in = sizeof(pkt_v4),
.repeat = 1,
);
err = bpf_prog_test_load("tailcall_bpf2bpf4.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
&obj, &prog_fd);
if (CHECK_FAIL(err))
return;
prog = bpf_object__find_program_by_name(obj, "entry");
if (CHECK_FAIL(!prog))
goto out;
main_fd = bpf_program__fd(prog);
if (CHECK_FAIL(main_fd < 0))
goto out;
prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
if (CHECK_FAIL(!prog_array))
goto out;
map_fd = bpf_map__fd(prog_array);
if (CHECK_FAIL(map_fd < 0))
goto out;
for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
prog = bpf_object__find_program_by_name(obj, prog_name);
if (CHECK_FAIL(!prog))
goto out;
prog_fd = bpf_program__fd(prog);
if (CHECK_FAIL(prog_fd < 0))
goto out;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
}
data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
goto out;
data_fd = bpf_map__fd(data_map);
if (CHECK_FAIL(data_fd < 0))
goto out;
i = 0;
val.noise = noise;
val.count = 0;
err = bpf_map_update_elem(data_fd, &i, &val, BPF_ANY);
if (CHECK_FAIL(err))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, sizeof(pkt_v4) * 3, "tailcall retval");
i = 0;
err = bpf_map_lookup_elem(data_fd, &i, &val);
ASSERT_OK(err, "tailcall count");
ASSERT_EQ(val.count, 31, "tailcall count");
out:
bpf_object__close(obj);
}
#include "tailcall_bpf2bpf6.skel.h"
/* Tail call counting works even when there is data on stack which is
* not aligned to 8 bytes.
*/
static void test_tailcall_bpf2bpf_6(void)
{
struct tailcall_bpf2bpf6 *obj;
int err, map_fd, prog_fd, main_fd, data_fd, i, val;
LIBBPF_OPTS(bpf_test_run_opts, topts,
.data_in = &pkt_v4,
.data_size_in = sizeof(pkt_v4),
.repeat = 1,
);
obj = tailcall_bpf2bpf6__open_and_load();
if (!ASSERT_OK_PTR(obj, "open and load"))
return;
main_fd = bpf_program__fd(obj->progs.entry);
if (!ASSERT_GE(main_fd, 0, "entry prog fd"))
goto out;
map_fd = bpf_map__fd(obj->maps.jmp_table);
if (!ASSERT_GE(map_fd, 0, "jmp_table map fd"))
goto out;
prog_fd = bpf_program__fd(obj->progs.classifier_0);
if (!ASSERT_GE(prog_fd, 0, "classifier_0 prog fd"))
goto out;
i = 0;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (!ASSERT_OK(err, "jmp_table map update"))
goto out;
err = bpf_prog_test_run_opts(main_fd, &topts);
ASSERT_OK(err, "entry prog test run");
ASSERT_EQ(topts.retval, 0, "tailcall retval");
data_fd = bpf_map__fd(obj->maps.bss);
if (!ASSERT_GE(data_fd, 0, "bss map fd"))
goto out;
i = 0;
err = bpf_map_lookup_elem(data_fd, &i, &val);
ASSERT_OK(err, "bss map lookup");
ASSERT_EQ(val, 1, "done flag is set");
out:
tailcall_bpf2bpf6__destroy(obj);
}
/* test_tailcall_bpf2bpf_fentry checks that the count value of the tail call
* limit enforcement matches with expectations when tailcall is preceded with
* bpf2bpf call, and the bpf2bpf call is traced by fentry.
*/
static void test_tailcall_bpf2bpf_fentry(void)
{
test_tailcall_count("tailcall_bpf2bpf2.bpf.o", true, false);
}
/* test_tailcall_bpf2bpf_fexit checks that the count value of the tail call
* limit enforcement matches with expectations when tailcall is preceded with
* bpf2bpf call, and the bpf2bpf call is traced by fexit.
*/
static void test_tailcall_bpf2bpf_fexit(void)
{
test_tailcall_count("tailcall_bpf2bpf2.bpf.o", false, true);
}
/* test_tailcall_bpf2bpf_fentry_fexit checks that the count value of the tail
* call limit enforcement matches with expectations when tailcall is preceded
* with bpf2bpf call, and the bpf2bpf call is traced by both fentry and fexit.
*/
static void test_tailcall_bpf2bpf_fentry_fexit(void)
{
test_tailcall_count("tailcall_bpf2bpf2.bpf.o", true, true);
}
/* test_tailcall_bpf2bpf_fentry_entry checks that the count value of the tail
* call limit enforcement matches with expectations when tailcall is preceded
* with bpf2bpf call, and the bpf2bpf caller is traced by fentry.
*/
static void test_tailcall_bpf2bpf_fentry_entry(void)
{
struct bpf_object *tgt_obj = NULL, *fentry_obj = NULL;
int err, map_fd, prog_fd, data_fd, i, val;
struct bpf_map *prog_array, *data_map;
struct bpf_link *fentry_link = NULL;
struct bpf_program *prog;
char buff[128] = {};
LIBBPF_OPTS(bpf_test_run_opts, topts,
.data_in = buff,
.data_size_in = sizeof(buff),
.repeat = 1,
);
err = bpf_prog_test_load("tailcall_bpf2bpf2.bpf.o",
BPF_PROG_TYPE_SCHED_CLS,
&tgt_obj, &prog_fd);
if (!ASSERT_OK(err, "load tgt_obj"))
return;
prog_array = bpf_object__find_map_by_name(tgt_obj, "jmp_table");
if (!ASSERT_OK_PTR(prog_array, "find jmp_table map"))
goto out;
map_fd = bpf_map__fd(prog_array);
if (!ASSERT_FALSE(map_fd < 0, "find jmp_table map fd"))
goto out;
prog = bpf_object__find_program_by_name(tgt_obj, "classifier_0");
if (!ASSERT_OK_PTR(prog, "find classifier_0 prog"))
goto out;
prog_fd = bpf_program__fd(prog);
if (!ASSERT_FALSE(prog_fd < 0, "find classifier_0 prog fd"))
goto out;
i = 0;
err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
if (!ASSERT_OK(err, "update jmp_table"))
goto out;
fentry_obj = bpf_object__open_file("tailcall_bpf2bpf_fentry.bpf.o",
NULL);
if (!ASSERT_OK_PTR(fentry_obj, "open fentry_obj file"))
goto out;
prog = bpf_object__find_program_by_name(fentry_obj, "fentry");
if (!ASSERT_OK_PTR(prog, "find fentry prog"))
goto out;
err = bpf_program__set_attach_target(prog, prog_fd, "classifier_0");
if (!ASSERT_OK(err, "set_attach_target classifier_0"))
goto out;
err = bpf_object__load(fentry_obj);
if (!ASSERT_OK(err, "load fentry_obj"))
goto out;
fentry_link = bpf_program__attach_trace(prog);
if (!ASSERT_OK_PTR(fentry_link, "attach_trace"))
goto out;
err = bpf_prog_test_run_opts(prog_fd, &topts);
ASSERT_OK(err, "tailcall");
ASSERT_EQ(topts.retval, 1, "tailcall retval");
data_map = bpf_object__find_map_by_name(tgt_obj, "tailcall.bss");
if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
"find tailcall.bss map"))
goto out;
data_fd = bpf_map__fd(data_map);
if (!ASSERT_FALSE(data_fd < 0, "find tailcall.bss map fd"))
goto out;
i = 0;
err = bpf_map_lookup_elem(data_fd, &i, &val);
ASSERT_OK(err, "tailcall count");
ASSERT_EQ(val, 34, "tailcall count");
data_map = bpf_object__find_map_by_name(fentry_obj, ".bss");
if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
"find tailcall_bpf2bpf_fentry.bss map"))
goto out;
data_fd = bpf_map__fd(data_map);
if (!ASSERT_FALSE(data_fd < 0,
"find tailcall_bpf2bpf_fentry.bss map fd"))
goto out;
i = 0;
err = bpf_map_lookup_elem(data_fd, &i, &val);
ASSERT_OK(err, "fentry count");
ASSERT_EQ(val, 1, "fentry count");
out:
bpf_link__destroy(fentry_link);
bpf_object__close(fentry_obj);
bpf_object__close(tgt_obj);
}
#define JMP_TABLE "/sys/fs/bpf/jmp_table"
static int poke_thread_exit;
static void *poke_update(void *arg)
{
__u32 zero = 0, prog1_fd, prog2_fd, map_fd;
struct tailcall_poke *call = arg;
map_fd = bpf_map__fd(call->maps.jmp_table);
prog1_fd = bpf_program__fd(call->progs.call1);
prog2_fd = bpf_program__fd(call->progs.call2);
while (!poke_thread_exit) {
bpf_map_update_elem(map_fd, &zero, &prog1_fd, BPF_ANY);
bpf_map_update_elem(map_fd, &zero, &prog2_fd, BPF_ANY);
}
return NULL;
}
/*
* We are trying to hit prog array update during another program load
* that shares the same prog array map.
*
* For that we share the jmp_table map between two skeleton instances
* by pinning the jmp_table to same path. Then first skeleton instance
* periodically updates jmp_table in 'poke update' thread while we load
* the second skeleton instance in the main thread.
*/
static void test_tailcall_poke(void)
{
struct tailcall_poke *call, *test;
int err, cnt = 10;
pthread_t thread;
unlink(JMP_TABLE);
call = tailcall_poke__open_and_load();
if (!ASSERT_OK_PTR(call, "tailcall_poke__open"))
return;
err = bpf_map__pin(call->maps.jmp_table, JMP_TABLE);
if (!ASSERT_OK(err, "bpf_map__pin"))
goto out;
err = pthread_create(&thread, NULL, poke_update, call);
if (!ASSERT_OK(err, "new toggler"))
goto out;
while (cnt--) {
test = tailcall_poke__open();
if (!ASSERT_OK_PTR(test, "tailcall_poke__open"))
break;
err = bpf_map__set_pin_path(test->maps.jmp_table, JMP_TABLE);
if (!ASSERT_OK(err, "bpf_map__pin")) {
tailcall_poke__destroy(test);
break;
}
bpf_program__set_autoload(test->progs.test, true);
bpf_program__set_autoload(test->progs.call1, false);
bpf_program__set_autoload(test->progs.call2, false);
err = tailcall_poke__load(test);
tailcall_poke__destroy(test);
if (!ASSERT_OK(err, "tailcall_poke__load"))
break;
}
poke_thread_exit = 1;
ASSERT_OK(pthread_join(thread, NULL), "pthread_join");
out:
bpf_map__unpin(call->maps.jmp_table, JMP_TABLE);
tailcall_poke__destroy(call);
}
void test_tailcalls(void)
{
if (test__start_subtest("tailcall_1"))
test_tailcall_1();
if (test__start_subtest("tailcall_2"))
test_tailcall_2();
if (test__start_subtest("tailcall_3"))
test_tailcall_3();
if (test__start_subtest("tailcall_4"))
test_tailcall_4();
if (test__start_subtest("tailcall_5"))
test_tailcall_5();
if (test__start_subtest("tailcall_6"))
test_tailcall_6();
if (test__start_subtest("tailcall_bpf2bpf_1"))
test_tailcall_bpf2bpf_1();
if (test__start_subtest("tailcall_bpf2bpf_2"))
test_tailcall_bpf2bpf_2();
if (test__start_subtest("tailcall_bpf2bpf_3"))
test_tailcall_bpf2bpf_3();
if (test__start_subtest("tailcall_bpf2bpf_4"))
test_tailcall_bpf2bpf_4(false);
if (test__start_subtest("tailcall_bpf2bpf_5"))
test_tailcall_bpf2bpf_4(true);
if (test__start_subtest("tailcall_bpf2bpf_6"))
test_tailcall_bpf2bpf_6();
if (test__start_subtest("tailcall_bpf2bpf_fentry"))
test_tailcall_bpf2bpf_fentry();
if (test__start_subtest("tailcall_bpf2bpf_fexit"))
test_tailcall_bpf2bpf_fexit();
if (test__start_subtest("tailcall_bpf2bpf_fentry_fexit"))
test_tailcall_bpf2bpf_fentry_fexit();
if (test__start_subtest("tailcall_bpf2bpf_fentry_entry"))
test_tailcall_bpf2bpf_fentry_entry();
if (test__start_subtest("tailcall_poke"))
test_tailcall_poke();
}
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