// SPDX-License-Identifier: GPL-2.0

#include <test_progs.h>
#include "cgroup_helpers.h"
#include "testing_helpers.h"
#include "test_cgroup_link.skel.h"

static __u32 duration = 0;
#define PING_CMD        "ping -q -c1 -w1 127.0.0.1 > /dev/null"

static struct test_cgroup_link *skel = NULL;

int ping_and_check(int exp_calls, int exp_alt_calls)
{
        skel->bss->calls = 0;
        skel->bss->alt_calls = 0;
        CHECK_FAIL(system(PING_CMD));
        if (CHECK(skel->bss->calls != exp_calls, "call_cnt",
                  "exp %d, got %d\n", exp_calls, skel->bss->calls))
                return -EINVAL;
        if (CHECK(skel->bss->alt_calls != exp_alt_calls, "alt_call_cnt",
                  "exp %d, got %d\n", exp_alt_calls, skel->bss->alt_calls))
                return -EINVAL;
        return 0;
}

void serial_test_cgroup_link(void)
{
        struct {
                const char *path;
                int fd;
        } cgs[] = {
                { "/cg1" },
                { "/cg1/cg2" },
                { "/cg1/cg2/cg3" },
                { "/cg1/cg2/cg3/cg4" },
        };
        int last_cg = ARRAY_SIZE(cgs) - 1, cg_nr = ARRAY_SIZE(cgs);
        DECLARE_LIBBPF_OPTS(bpf_link_update_opts, link_upd_opts);
        struct bpf_link *links[ARRAY_SIZE(cgs)] = {}, *tmp_link;
        __u32 prog_ids[ARRAY_SIZE(cgs)], prog_cnt = 0, attach_flags, prog_id;
        struct bpf_link_info info;
        int i = 0, err, prog_fd;
        bool detach_legacy = false;

        skel = test_cgroup_link__open_and_load();
        if (CHECK(!skel, "skel_open_load", "failed to open/load skeleton\n"))
                return;
        prog_fd = bpf_program__fd(skel->progs.egress);

        err = setup_cgroup_environment();
        if (CHECK(err, "cg_init", "failed: %d\n", err))
                goto cleanup;

        for (i = 0; i < cg_nr; i++) {
                cgs[i].fd = create_and_get_cgroup(cgs[i].path);
                if (!ASSERT_GE(cgs[i].fd, 0, "cg_create"))
                        goto cleanup;
        }

        err = join_cgroup(cgs[last_cg].path);
        if (CHECK(err, "cg_join", "fail: %d\n", err))
                goto cleanup;

        for (i = 0; i < cg_nr; i++) {
                links[i] = bpf_program__attach_cgroup(skel->progs.egress,
                                                      cgs[i].fd);
                if (!ASSERT_OK_PTR(links[i], "cg_attach"))
                        goto cleanup;
        }

        ping_and_check(cg_nr, 0);

        /* query the number of attached progs and attach flags in root cg */
        err = bpf_prog_query(cgs[0].fd, BPF_CGROUP_INET_EGRESS,
                             0, &attach_flags, NULL, &prog_cnt);
        CHECK_FAIL(err);
        CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI);
        if (CHECK(prog_cnt != 1, "effect_cnt", "exp %d, got %d\n", 1, prog_cnt))
                goto cleanup;

        /* query the number of effective progs in last cg */
        err = bpf_prog_query(cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS,
                             BPF_F_QUERY_EFFECTIVE, NULL, NULL,
                             &prog_cnt);
        CHECK_FAIL(err);
        if (CHECK(prog_cnt != cg_nr, "effect_cnt", "exp %d, got %d\n",
                  cg_nr, prog_cnt))
                goto cleanup;

        /* query the effective prog IDs in last cg */
        err = bpf_prog_query(cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS,
                             BPF_F_QUERY_EFFECTIVE, NULL, prog_ids,
                             &prog_cnt);
        CHECK_FAIL(err);
        if (CHECK(prog_cnt != cg_nr, "effect_cnt", "exp %d, got %d\n",
                  cg_nr, prog_cnt))
                goto cleanup;
        for (i = 1; i < prog_cnt; i++) {
                CHECK(prog_ids[i - 1] != prog_ids[i], "prog_id_check",
                      "idx %d, prev id %d, cur id %d\n",
                      i, prog_ids[i - 1], prog_ids[i]);
        }

        /* detach bottom program and ping again */
        bpf_link__destroy(links[last_cg]);
        links[last_cg] = NULL;

        ping_and_check(cg_nr - 1, 0);

        /* mix in with non link-based multi-attachments */
        err = bpf_prog_attach(prog_fd, cgs[last_cg].fd,
                              BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_MULTI);
        if (CHECK(err, "cg_attach_legacy", "errno=%d\n", errno))
                goto cleanup;
        detach_legacy = true;

        links[last_cg] = bpf_program__attach_cgroup(skel->progs.egress,
                                                    cgs[last_cg].fd);
        if (!ASSERT_OK_PTR(links[last_cg], "cg_attach"))
                goto cleanup;

        ping_and_check(cg_nr + 1, 0);

        /* detach link */
        bpf_link__destroy(links[last_cg]);
        links[last_cg] = NULL;

        /* detach legacy */
        err = bpf_prog_detach2(prog_fd, cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS);
        if (CHECK(err, "cg_detach_legacy", "errno=%d\n", errno))
                goto cleanup;
        detach_legacy = false;

        /* attach legacy exclusive prog attachment */
        err = bpf_prog_attach(prog_fd, cgs[last_cg].fd,
                              BPF_CGROUP_INET_EGRESS, 0);
        if (CHECK(err, "cg_attach_exclusive", "errno=%d\n", errno))
                goto cleanup;
        detach_legacy = true;

        /* attempt to mix in with multi-attach bpf_link */
        tmp_link = bpf_program__attach_cgroup(skel->progs.egress,
                                              cgs[last_cg].fd);
        if (!ASSERT_ERR_PTR(tmp_link, "cg_attach_fail")) {
                bpf_link__destroy(tmp_link);
                goto cleanup;
        }

        ping_and_check(cg_nr, 0);

        /* detach */
        err = bpf_prog_detach2(prog_fd, cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS);
        if (CHECK(err, "cg_detach_legacy", "errno=%d\n", errno))
                goto cleanup;
        detach_legacy = false;

        ping_and_check(cg_nr - 1, 0);

        /* attach back link-based one */
        links[last_cg] = bpf_program__attach_cgroup(skel->progs.egress,
                                                    cgs[last_cg].fd);
        if (!ASSERT_OK_PTR(links[last_cg], "cg_attach"))
                goto cleanup;

        ping_and_check(cg_nr, 0);

        /* check legacy exclusive prog can't be attached */
        err = bpf_prog_attach(prog_fd, cgs[last_cg].fd,
                              BPF_CGROUP_INET_EGRESS, 0);
        if (CHECK(!err, "cg_attach_exclusive", "unexpected success")) {
                bpf_prog_detach2(prog_fd, cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS);
                goto cleanup;
        }

        /* replace BPF programs inside their links for all but first link */
        for (i = 1; i < cg_nr; i++) {
                err = bpf_link__update_program(links[i], skel->progs.egress_alt);
                if (CHECK(err, "prog_upd", "link #%d\n", i))
                        goto cleanup;
        }

        ping_and_check(1, cg_nr - 1);

        /* Attempt program update with wrong expected BPF program */
        link_upd_opts.old_prog_fd = bpf_program__fd(skel->progs.egress_alt);
        link_upd_opts.flags = BPF_F_REPLACE;
        err = bpf_link_update(bpf_link__fd(links[0]),
                              bpf_program__fd(skel->progs.egress_alt),
                              &link_upd_opts);
        if (CHECK(err == 0 || errno != EPERM, "prog_cmpxchg1",
                  "unexpectedly succeeded, err %d, errno %d\n", err, -errno))
                goto cleanup;

        /* Compare-exchange single link program from egress to egress_alt */
        link_upd_opts.old_prog_fd = bpf_program__fd(skel->progs.egress);
        link_upd_opts.flags = BPF_F_REPLACE;
        err = bpf_link_update(bpf_link__fd(links[0]),
                              bpf_program__fd(skel->progs.egress_alt),
                              &link_upd_opts);
        if (CHECK(err, "prog_cmpxchg2", "errno %d\n", -errno))
                goto cleanup;

        /* ping */
        ping_and_check(0, cg_nr);

        /* close cgroup FDs before detaching links */
        for (i = 0; i < cg_nr; i++) {
                if (cgs[i].fd > 0) {
                        close(cgs[i].fd);
                        cgs[i].fd = -1;
                }
        }

        /* BPF programs should still get called */
        ping_and_check(0, cg_nr);

        prog_id = link_info_prog_id(links[0], &info);
        CHECK(prog_id == 0, "link_info", "failed\n");
        CHECK(info.cgroup.cgroup_id == 0, "cgroup_id", "unexpected %llu\n", info.cgroup.cgroup_id);

        err = bpf_link__detach(links[0]);
        if (CHECK(err, "link_detach", "failed %d\n", err))
                goto cleanup;

        /* cgroup_id should be zero in link_info */
        prog_id = link_info_prog_id(links[0], &info);
        CHECK(prog_id == 0, "link_info", "failed\n");
        CHECK(info.cgroup.cgroup_id != 0, "cgroup_id", "unexpected %llu\n", info.cgroup.cgroup_id);

        /* First BPF program shouldn't be called anymore */
        ping_and_check(0, cg_nr - 1);

        /* leave cgroup and remove them, don't detach programs */
        cleanup_cgroup_environment();

        /* BPF programs should have been auto-detached */
        ping_and_check(0, 0);

cleanup:
        if (detach_legacy)
                bpf_prog_detach2(prog_fd, cgs[last_cg].fd,
                                 BPF_CGROUP_INET_EGRESS);

        for (i = 0; i < cg_nr; i++) {
                bpf_link__destroy(links[i]);
        }
        test_cgroup_link__destroy(skel);

        for (i = 0; i < cg_nr; i++) {
                if (cgs[i].fd > 0)
                        close(cgs[i].fd);
        }
        cleanup_cgroup_environment();
}