// SPDX-License-Identifier: GPL-2.0
/* Check what features does the kernel support (where the selftest is running).
 * Somewhat inspired by CRIU kerndat/kdat kernel features detector.
 */
#include <pthread.h>
#include "aolib.h"

struct kconfig_t {
        int _error;             /* negative errno if not supported */
        int (*check_kconfig)(int *error);
};

static int has_net_ns(int *err)
{
        if (access("/proc/self/ns/net", F_OK) < 0) {
                *err = errno;
                if (errno == ENOENT)
                        return 0;
                test_print("Unable to access /proc/self/ns/net: %m");
                return -errno;
        }
        return *err = errno = 0;
}

static int has_veth(int *err)
{
        int orig_netns, ns_a, ns_b;

        orig_netns = open_netns();
        ns_a = unshare_open_netns();
        ns_b = unshare_open_netns();

        *err = add_veth("check_veth", ns_a, ns_b);

        switch_ns(orig_netns);
        close(orig_netns);
        close(ns_a);
        close(ns_b);
        return 0;
}

static int has_tcp_ao(int *err)
{
        struct sockaddr_in addr = {
                .sin_family = test_family,
        };
        struct tcp_ao_add tmp = {};
        const char *password = DEFAULT_TEST_PASSWORD;
        int sk, ret = 0;

        sk = socket(test_family, SOCK_STREAM, IPPROTO_TCP);
        if (sk < 0) {
                test_print("socket(): %m");
                return -errno;
        }

        tmp.sndid = 100;
        tmp.rcvid = 100;
        tmp.keylen = strlen(password);
        memcpy(tmp.key, password, strlen(password));
        strcpy(tmp.alg_name, "hmac(sha1)");
        memcpy(&tmp.addr, &addr, sizeof(addr));
        *err = 0;
        if (setsockopt(sk, IPPROTO_TCP, TCP_AO_ADD_KEY, &tmp, sizeof(tmp)) < 0) {
                *err = -errno;
                if (errno != ENOPROTOOPT)
                        ret = -errno;
        }
        close(sk);
        return ret;
}

static int has_tcp_md5(int *err)
{
        union tcp_addr addr_any = {};
        int sk, ret = 0;

        sk = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
        if (sk < 0) {
                test_print("socket(): %m");
                return -errno;
        }

        /*
         * Under CONFIG_CRYPTO_FIPS=y it fails with ENOMEM, rather with
         * anything more descriptive. Oh well.
         */
        *err = 0;
        if (test_set_md5(sk, addr_any, 0, -1, DEFAULT_TEST_PASSWORD)) {
                *err = -errno;
                if (errno != ENOPROTOOPT && errno == ENOMEM) {
                        test_print("setsockopt(TCP_MD5SIG_EXT): %m");
                        ret = -errno;
                }
        }
        close(sk);
        return ret;
}

static int has_vrfs(int *err)
{
        int orig_netns, ns_test, ret = 0;

        orig_netns = open_netns();
        ns_test = unshare_open_netns();

        *err = add_vrf("ksft-check", 55, 101, ns_test);
        if (*err && *err != -EOPNOTSUPP) {
                test_print("Failed to add a VRF: %d", *err);
                ret = *err;
        }

        switch_ns(orig_netns);
        close(orig_netns);
        close(ns_test);
        return ret;
}

static int has_ftrace(int *err)
{
        *err = test_setup_tracing();
        return 0;
}

#define KCONFIG_UNKNOWN                 1
static pthread_mutex_t kconfig_lock = PTHREAD_MUTEX_INITIALIZER;
static struct kconfig_t kconfig[__KCONFIG_LAST__] = {
        { KCONFIG_UNKNOWN, has_net_ns },
        { KCONFIG_UNKNOWN, has_veth },
        { KCONFIG_UNKNOWN, has_tcp_ao },
        { KCONFIG_UNKNOWN, has_tcp_md5 },
        { KCONFIG_UNKNOWN, has_vrfs },
        { KCONFIG_UNKNOWN, has_ftrace },
};

const char *tests_skip_reason[__KCONFIG_LAST__] = {
        "Tests require network namespaces support (CONFIG_NET_NS)",
        "Tests require veth support (CONFIG_VETH)",
        "Tests require TCP-AO support (CONFIG_TCP_AO)",
        "setsockopt(TCP_MD5SIG_EXT) is not supported (CONFIG_TCP_MD5)",
        "VRFs are not supported (CONFIG_NET_VRF)",
        "Ftrace points are not supported (CONFIG_TRACEPOINTS)",
};

bool kernel_config_has(enum test_needs_kconfig k)
{
        bool ret;

        pthread_mutex_lock(&kconfig_lock);
        if (kconfig[k]._error == KCONFIG_UNKNOWN) {
                if (kconfig[k].check_kconfig(&kconfig[k]._error))
                        test_error("Failed to initialize kconfig %u", k);
        }
        ret = kconfig[k]._error == 0;
        pthread_mutex_unlock(&kconfig_lock);
        return ret;
}