selftests/bpf: Add tests for attaching bpf_link to netns

Extend the existing test case for flow dissector attaching to cover:

 - link creation,
 - link updates,
 - link info querying,
 - mixing links with direct prog attachment.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200531082846.2117903-10-jakub@cloudflare.com
This commit is contained in:
Jakub Sitnicki 2020-05-31 10:28:43 +02:00 committed by Alexei Starovoitov
parent e948947a6e
commit 1f043f87bb

View file

@ -11,6 +11,7 @@
#include <fcntl.h>
#include <sched.h>
#include <stdbool.h>
#include <sys/stat.h>
#include <unistd.h>
#include <linux/bpf.h>
@ -18,21 +19,30 @@
#include "test_progs.h"
static bool is_attached(int netns)
static int init_net = -1;
static __u32 query_attached_prog_id(int netns)
{
__u32 cnt;
__u32 prog_ids[1] = {};
__u32 prog_cnt = ARRAY_SIZE(prog_ids);
int err;
err = bpf_prog_query(netns, BPF_FLOW_DISSECTOR, 0, NULL, NULL, &cnt);
err = bpf_prog_query(netns, BPF_FLOW_DISSECTOR, 0, NULL,
prog_ids, &prog_cnt);
if (CHECK_FAIL(err)) {
perror("bpf_prog_query");
return true; /* fail-safe */
return 0;
}
return cnt > 0;
return prog_cnt == 1 ? prog_ids[0] : 0;
}
static int load_prog(void)
static bool prog_is_attached(int netns)
{
return query_attached_prog_id(netns) > 0;
}
static int load_prog(enum bpf_prog_type type)
{
struct bpf_insn prog[] = {
BPF_MOV64_IMM(BPF_REG_0, BPF_OK),
@ -40,61 +50,566 @@ static int load_prog(void)
};
int fd;
fd = bpf_load_program(BPF_PROG_TYPE_FLOW_DISSECTOR, prog,
ARRAY_SIZE(prog), "GPL", 0, NULL, 0);
fd = bpf_load_program(type, prog, ARRAY_SIZE(prog), "GPL", 0, NULL, 0);
if (CHECK_FAIL(fd < 0))
perror("bpf_load_program");
return fd;
}
static void do_flow_dissector_reattach(void)
static __u32 query_prog_id(int prog)
{
int prog_fd[2] = { -1, -1 };
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
int err;
prog_fd[0] = load_prog();
if (prog_fd[0] < 0)
return;
prog_fd[1] = load_prog();
if (prog_fd[1] < 0)
goto out_close;
err = bpf_prog_attach(prog_fd[0], 0, BPF_FLOW_DISSECTOR, 0);
if (CHECK_FAIL(err)) {
perror("bpf_prog_attach-0");
goto out_close;
err = bpf_obj_get_info_by_fd(prog, &info, &info_len);
if (CHECK_FAIL(err || info_len != sizeof(info))) {
perror("bpf_obj_get_info_by_fd");
return 0;
}
return info.id;
}
static int unshare_net(int old_net)
{
int err, new_net;
err = unshare(CLONE_NEWNET);
if (CHECK_FAIL(err)) {
perror("unshare(CLONE_NEWNET)");
return -1;
}
new_net = open("/proc/self/ns/net", O_RDONLY);
if (CHECK_FAIL(new_net < 0)) {
perror("open(/proc/self/ns/net)");
setns(old_net, CLONE_NEWNET);
return -1;
}
return new_net;
}
static void test_prog_attach_prog_attach(int netns, int prog1, int prog2)
{
int err;
err = bpf_prog_attach(prog1, 0, BPF_FLOW_DISSECTOR, 0);
if (CHECK_FAIL(err)) {
perror("bpf_prog_attach(prog1)");
return;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
/* Expect success when attaching a different program */
err = bpf_prog_attach(prog_fd[1], 0, BPF_FLOW_DISSECTOR, 0);
err = bpf_prog_attach(prog2, 0, BPF_FLOW_DISSECTOR, 0);
if (CHECK_FAIL(err)) {
perror("bpf_prog_attach-1");
perror("bpf_prog_attach(prog2) #1");
goto out_detach;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog2));
/* Expect failure when attaching the same program twice */
err = bpf_prog_attach(prog_fd[1], 0, BPF_FLOW_DISSECTOR, 0);
err = bpf_prog_attach(prog2, 0, BPF_FLOW_DISSECTOR, 0);
if (CHECK_FAIL(!err || errno != EINVAL))
perror("bpf_prog_attach-2");
perror("bpf_prog_attach(prog2) #2");
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog2));
out_detach:
err = bpf_prog_detach(0, BPF_FLOW_DISSECTOR);
if (CHECK_FAIL(err))
perror("bpf_prog_detach");
CHECK_FAIL(prog_is_attached(netns));
}
static void test_link_create_link_create(int netns, int prog1, int prog2)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts);
int link1, link2;
link1 = bpf_link_create(prog1, netns, BPF_FLOW_DISSECTOR, &opts);
if (CHECK_FAIL(link < 0)) {
perror("bpf_link_create(prog1)");
return;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
/* Expect failure creating link when another link exists */
errno = 0;
link2 = bpf_link_create(prog2, netns, BPF_FLOW_DISSECTOR, &opts);
if (CHECK_FAIL(link2 != -1 || errno != E2BIG))
perror("bpf_prog_attach(prog2) expected E2BIG");
if (link2 != -1)
close(link2);
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
close(link1);
CHECK_FAIL(prog_is_attached(netns));
}
static void test_prog_attach_link_create(int netns, int prog1, int prog2)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts);
int err, link;
err = bpf_prog_attach(prog1, -1, BPF_FLOW_DISSECTOR, 0);
if (CHECK_FAIL(err)) {
perror("bpf_prog_attach(prog1)");
return;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
/* Expect failure creating link when prog attached */
errno = 0;
link = bpf_link_create(prog2, netns, BPF_FLOW_DISSECTOR, &opts);
if (CHECK_FAIL(link != -1 || errno != EEXIST))
perror("bpf_link_create(prog2) expected EEXIST");
if (link != -1)
close(link);
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
err = bpf_prog_detach(-1, BPF_FLOW_DISSECTOR);
if (CHECK_FAIL(err))
perror("bpf_prog_detach");
CHECK_FAIL(prog_is_attached(netns));
}
static void test_link_create_prog_attach(int netns, int prog1, int prog2)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts);
int err, link;
link = bpf_link_create(prog1, netns, BPF_FLOW_DISSECTOR, &opts);
if (CHECK_FAIL(link < 0)) {
perror("bpf_link_create(prog1)");
return;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
/* Expect failure attaching prog when link exists */
errno = 0;
err = bpf_prog_attach(prog2, -1, BPF_FLOW_DISSECTOR, 0);
if (CHECK_FAIL(!err || errno != EEXIST))
perror("bpf_prog_attach(prog2) expected EEXIST");
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
close(link);
CHECK_FAIL(prog_is_attached(netns));
}
static void test_link_create_prog_detach(int netns, int prog1, int prog2)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts);
int err, link;
link = bpf_link_create(prog1, netns, BPF_FLOW_DISSECTOR, &opts);
if (CHECK_FAIL(link < 0)) {
perror("bpf_link_create(prog1)");
return;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
/* Expect failure detaching prog when link exists */
errno = 0;
err = bpf_prog_detach(-1, BPF_FLOW_DISSECTOR);
if (CHECK_FAIL(!err || errno != EINVAL))
perror("bpf_prog_detach expected EINVAL");
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
close(link);
CHECK_FAIL(prog_is_attached(netns));
}
static void test_prog_attach_detach_query(int netns, int prog1, int prog2)
{
int err;
err = bpf_prog_attach(prog1, 0, BPF_FLOW_DISSECTOR, 0);
if (CHECK_FAIL(err)) {
perror("bpf_prog_attach(prog1)");
return;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
err = bpf_prog_detach(0, BPF_FLOW_DISSECTOR);
if (CHECK_FAIL(err)) {
perror("bpf_prog_detach");
return;
}
/* Expect no prog attached after successful detach */
CHECK_FAIL(prog_is_attached(netns));
}
static void test_link_create_close_query(int netns, int prog1, int prog2)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts);
int link;
link = bpf_link_create(prog1, netns, BPF_FLOW_DISSECTOR, &opts);
if (CHECK_FAIL(link < 0)) {
perror("bpf_link_create(prog1)");
return;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
close(link);
/* Expect no prog attached after closing last link FD */
CHECK_FAIL(prog_is_attached(netns));
}
static void test_link_update_no_old_prog(int netns, int prog1, int prog2)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, create_opts);
DECLARE_LIBBPF_OPTS(bpf_link_update_opts, update_opts);
int err, link;
link = bpf_link_create(prog1, netns, BPF_FLOW_DISSECTOR, &create_opts);
if (CHECK_FAIL(link < 0)) {
perror("bpf_link_create(prog1)");
return;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
/* Expect success replacing the prog when old prog not specified */
update_opts.flags = 0;
update_opts.old_prog_fd = 0;
err = bpf_link_update(link, prog2, &update_opts);
if (CHECK_FAIL(err))
perror("bpf_link_update");
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog2));
close(link);
CHECK_FAIL(prog_is_attached(netns));
}
static void test_link_update_replace_old_prog(int netns, int prog1, int prog2)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, create_opts);
DECLARE_LIBBPF_OPTS(bpf_link_update_opts, update_opts);
int err, link;
link = bpf_link_create(prog1, netns, BPF_FLOW_DISSECTOR, &create_opts);
if (CHECK_FAIL(link < 0)) {
perror("bpf_link_create(prog1)");
return;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
/* Expect success F_REPLACE and old prog specified to succeed */
update_opts.flags = BPF_F_REPLACE;
update_opts.old_prog_fd = prog1;
err = bpf_link_update(link, prog2, &update_opts);
if (CHECK_FAIL(err))
perror("bpf_link_update");
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog2));
close(link);
CHECK_FAIL(prog_is_attached(netns));
}
static void test_link_update_invalid_opts(int netns, int prog1, int prog2)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, create_opts);
DECLARE_LIBBPF_OPTS(bpf_link_update_opts, update_opts);
int err, link;
link = bpf_link_create(prog1, netns, BPF_FLOW_DISSECTOR, &create_opts);
if (CHECK_FAIL(link < 0)) {
perror("bpf_link_create(prog1)");
return;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
/* Expect update to fail w/ old prog FD but w/o F_REPLACE*/
errno = 0;
update_opts.flags = 0;
update_opts.old_prog_fd = prog1;
err = bpf_link_update(link, prog2, &update_opts);
if (CHECK_FAIL(!err || errno != EINVAL)) {
perror("bpf_link_update expected EINVAL");
goto out_close;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
/* Expect update to fail on old prog FD mismatch */
errno = 0;
update_opts.flags = BPF_F_REPLACE;
update_opts.old_prog_fd = prog2;
err = bpf_link_update(link, prog2, &update_opts);
if (CHECK_FAIL(!err || errno != EPERM)) {
perror("bpf_link_update expected EPERM");
goto out_close;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
/* Expect update to fail for invalid old prog FD */
errno = 0;
update_opts.flags = BPF_F_REPLACE;
update_opts.old_prog_fd = -1;
err = bpf_link_update(link, prog2, &update_opts);
if (CHECK_FAIL(!err || errno != EBADF)) {
perror("bpf_link_update expected EBADF");
goto out_close;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
/* Expect update to fail with invalid flags */
errno = 0;
update_opts.flags = BPF_F_ALLOW_MULTI;
update_opts.old_prog_fd = 0;
err = bpf_link_update(link, prog2, &update_opts);
if (CHECK_FAIL(!err || errno != EINVAL))
perror("bpf_link_update expected EINVAL");
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
out_close:
close(prog_fd[1]);
close(prog_fd[0]);
close(link);
CHECK_FAIL(prog_is_attached(netns));
}
static void test_link_update_invalid_prog(int netns, int prog1, int prog2)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, create_opts);
DECLARE_LIBBPF_OPTS(bpf_link_update_opts, update_opts);
int err, link, prog3;
link = bpf_link_create(prog1, netns, BPF_FLOW_DISSECTOR, &create_opts);
if (CHECK_FAIL(link < 0)) {
perror("bpf_link_create(prog1)");
return;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
/* Expect failure when new prog FD is not valid */
errno = 0;
update_opts.flags = 0;
update_opts.old_prog_fd = 0;
err = bpf_link_update(link, -1, &update_opts);
if (CHECK_FAIL(!err || errno != EBADF)) {
perror("bpf_link_update expected EINVAL");
goto out_close_link;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
prog3 = load_prog(BPF_PROG_TYPE_SOCKET_FILTER);
if (prog3 < 0)
goto out_close_link;
/* Expect failure when new prog FD type doesn't match */
errno = 0;
update_opts.flags = 0;
update_opts.old_prog_fd = 0;
err = bpf_link_update(link, prog3, &update_opts);
if (CHECK_FAIL(!err || errno != EINVAL))
perror("bpf_link_update expected EINVAL");
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
close(prog3);
out_close_link:
close(link);
CHECK_FAIL(prog_is_attached(netns));
}
static void test_link_update_netns_gone(int netns, int prog1, int prog2)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, create_opts);
DECLARE_LIBBPF_OPTS(bpf_link_update_opts, update_opts);
int err, link, old_net;
old_net = netns;
netns = unshare_net(old_net);
if (netns < 0)
return;
link = bpf_link_create(prog1, netns, BPF_FLOW_DISSECTOR, &create_opts);
if (CHECK_FAIL(link < 0)) {
perror("bpf_link_create(prog1)");
return;
}
CHECK_FAIL(query_attached_prog_id(netns) != query_prog_id(prog1));
close(netns);
err = setns(old_net, CLONE_NEWNET);
if (CHECK_FAIL(err)) {
perror("setns(CLONE_NEWNET)");
close(link);
return;
}
/* Expect failure when netns destroyed */
errno = 0;
update_opts.flags = 0;
update_opts.old_prog_fd = 0;
err = bpf_link_update(link, prog2, &update_opts);
if (CHECK_FAIL(!err || errno != ENOLINK))
perror("bpf_link_update");
close(link);
}
static void test_link_get_info(int netns, int prog1, int prog2)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, create_opts);
DECLARE_LIBBPF_OPTS(bpf_link_update_opts, update_opts);
struct bpf_link_info info = {};
struct stat netns_stat = {};
__u32 info_len, link_id;
int err, link, old_net;
old_net = netns;
netns = unshare_net(old_net);
if (netns < 0)
return;
err = fstat(netns, &netns_stat);
if (CHECK_FAIL(err)) {
perror("stat(netns)");
goto out_resetns;
}
link = bpf_link_create(prog1, netns, BPF_FLOW_DISSECTOR, &create_opts);
if (CHECK_FAIL(link < 0)) {
perror("bpf_link_create(prog1)");
goto out_resetns;
}
info_len = sizeof(info);
err = bpf_obj_get_info_by_fd(link, &info, &info_len);
if (CHECK_FAIL(err)) {
perror("bpf_obj_get_info");
goto out_unlink;
}
CHECK_FAIL(info_len != sizeof(info));
/* Expect link info to be sane and match prog and netns details */
CHECK_FAIL(info.type != BPF_LINK_TYPE_NETNS);
CHECK_FAIL(info.id == 0);
CHECK_FAIL(info.prog_id != query_prog_id(prog1));
CHECK_FAIL(info.netns.netns_ino != netns_stat.st_ino);
CHECK_FAIL(info.netns.attach_type != BPF_FLOW_DISSECTOR);
update_opts.flags = 0;
update_opts.old_prog_fd = 0;
err = bpf_link_update(link, prog2, &update_opts);
if (CHECK_FAIL(err)) {
perror("bpf_link_update(prog2)");
goto out_unlink;
}
link_id = info.id;
info_len = sizeof(info);
err = bpf_obj_get_info_by_fd(link, &info, &info_len);
if (CHECK_FAIL(err)) {
perror("bpf_obj_get_info");
goto out_unlink;
}
CHECK_FAIL(info_len != sizeof(info));
/* Expect no info change after update except in prog id */
CHECK_FAIL(info.type != BPF_LINK_TYPE_NETNS);
CHECK_FAIL(info.id != link_id);
CHECK_FAIL(info.prog_id != query_prog_id(prog2));
CHECK_FAIL(info.netns.netns_ino != netns_stat.st_ino);
CHECK_FAIL(info.netns.attach_type != BPF_FLOW_DISSECTOR);
/* Leave netns link is attached to and close last FD to it */
err = setns(old_net, CLONE_NEWNET);
if (CHECK_FAIL(err)) {
perror("setns(NEWNET)");
goto out_unlink;
}
close(netns);
old_net = -1;
netns = -1;
info_len = sizeof(info);
err = bpf_obj_get_info_by_fd(link, &info, &info_len);
if (CHECK_FAIL(err)) {
perror("bpf_obj_get_info");
goto out_unlink;
}
CHECK_FAIL(info_len != sizeof(info));
/* Expect netns_ino to change to 0 */
CHECK_FAIL(info.type != BPF_LINK_TYPE_NETNS);
CHECK_FAIL(info.id != link_id);
CHECK_FAIL(info.prog_id != query_prog_id(prog2));
CHECK_FAIL(info.netns.netns_ino != 0);
CHECK_FAIL(info.netns.attach_type != BPF_FLOW_DISSECTOR);
out_unlink:
close(link);
out_resetns:
if (old_net != -1)
setns(old_net, CLONE_NEWNET);
if (netns != -1)
close(netns);
}
static void run_tests(int netns)
{
struct test {
const char *test_name;
void (*test_func)(int netns, int prog1, int prog2);
} tests[] = {
{ "prog attach, prog attach",
test_prog_attach_prog_attach },
{ "link create, link create",
test_link_create_link_create },
{ "prog attach, link create",
test_prog_attach_link_create },
{ "link create, prog attach",
test_link_create_prog_attach },
{ "link create, prog detach",
test_link_create_prog_detach },
{ "prog attach, detach, query",
test_prog_attach_detach_query },
{ "link create, close, query",
test_link_create_close_query },
{ "link update no old prog",
test_link_update_no_old_prog },
{ "link update with replace old prog",
test_link_update_replace_old_prog },
{ "link update invalid opts",
test_link_update_invalid_opts },
{ "link update invalid prog",
test_link_update_invalid_prog },
{ "link update netns gone",
test_link_update_netns_gone },
{ "link get info",
test_link_get_info },
};
int i, progs[2] = { -1, -1 };
char test_name[80];
for (i = 0; i < ARRAY_SIZE(progs); i++) {
progs[i] = load_prog(BPF_PROG_TYPE_FLOW_DISSECTOR);
if (progs[i] < 0)
goto out_close;
}
for (i = 0; i < ARRAY_SIZE(tests); i++) {
snprintf(test_name, sizeof(test_name),
"flow dissector %s%s",
tests[i].test_name,
netns == init_net ? " (init_net)" : "");
if (test__start_subtest(test_name))
tests[i].test_func(netns, progs[0], progs[1]);
}
out_close:
for (i = 0; i < ARRAY_SIZE(progs); i++) {
if (progs[i] != -1)
CHECK_FAIL(close(progs[i]));
}
}
void test_flow_dissector_reattach(void)
{
int init_net, self_net, err;
int err, new_net, saved_net;
self_net = open("/proc/self/ns/net", O_RDONLY);
if (CHECK_FAIL(self_net < 0)) {
saved_net = open("/proc/self/ns/net", O_RDONLY);
if (CHECK_FAIL(saved_net < 0)) {
perror("open(/proc/self/ns/net");
return;
}
@ -111,30 +626,29 @@ void test_flow_dissector_reattach(void)
goto out_close;
}
if (is_attached(init_net)) {
if (prog_is_attached(init_net)) {
test__skip();
printf("Can't test with flow dissector attached to init_net\n");
goto out_setns;
}
/* First run tests in root network namespace */
do_flow_dissector_reattach();
run_tests(init_net);
/* Then repeat tests in a non-root namespace */
err = unshare(CLONE_NEWNET);
if (CHECK_FAIL(err)) {
perror("unshare(CLONE_NEWNET)");
new_net = unshare_net(init_net);
if (new_net < 0)
goto out_setns;
}
do_flow_dissector_reattach();
run_tests(new_net);
close(new_net);
out_setns:
/* Move back to netns we started in. */
err = setns(self_net, CLONE_NEWNET);
err = setns(saved_net, CLONE_NEWNET);
if (CHECK_FAIL(err))
perror("setns(/proc/self/ns/net)");
out_close:
close(init_net);
close(self_net);
close(saved_net);
}