path: root/clients/cloud-setup/nmcs-provider-ec2.c

// SPDX-License-Identifier: LGPL-2.1+

#include "nm-default.h"

#include "nmcs-provider-ec2.h"

#include "nm-cloud-setup-utils.h"

/*****************************************************************************/

#define HTTP_TIMEOUT_MS 3000

#define NM_EC2_HOST              "169.254.169.254"
#define NM_EC2_BASE              "http://" NM_EC2_HOST
#define NM_EC2_API_VERSION       "2018-09-24"
#define NM_EC2_METADATA_URL_BASE /* $NM_EC2_BASE/$NM_EC2_API_VERSION */ \
    "/meta-data/network/interfaces/macs/"

static const char *
_ec2_base(void)
{
    static const char *base_cached = NULL;
    const char *       base;

again:
    base = g_atomic_pointer_get(&base_cached);
    if (G_UNLIKELY(!base)) {
        /* The base URI can be set via environment variable.
		 * This is mainly for testing, it's not usually supposed to be configured.
		 * Consider this private API! */
        base = g_getenv(NMCS_ENV_VARIABLE("NM_CLOUD_SETUP_EC2_HOST"));

        if (base && base[0] && !strchr(base, '/')) {
            if (NM_STR_HAS_PREFIX(base, "http://") || NM_STR_HAS_PREFIX(base, "https://"))
                base = g_intern_string(base);
            else {
                gs_free char *s = NULL;

                s    = g_strconcat("http://", base, NULL);
                base = g_intern_string(s);
            }
        }
        if (!base)
            base = NM_EC2_BASE;

        nm_assert(!NM_STR_HAS_SUFFIX(base, "/"));

        if (!g_atomic_pointer_compare_and_exchange(&base_cached, NULL, base))
            goto again;
    }

    return base;
}

#define _ec2_uri_concat(...) nmcs_utils_uri_build_concat(_ec2_base(), __VA_ARGS__)
#define _ec2_uri_interfaces(...) \
    _ec2_uri_concat(NM_EC2_API_VERSION, NM_EC2_METADATA_URL_BASE, ##__VA_ARGS__)

/*****************************************************************************/

struct _NMCSProviderEC2 {
    NMCSProvider parent;
};

struct _NMCSProviderEC2Class {
    NMCSProviderClass parent;
};

G_DEFINE_TYPE(NMCSProviderEC2, nmcs_provider_ec2, NMCS_TYPE_PROVIDER);

/*****************************************************************************/

static gboolean
_detect_get_meta_data_check_cb(long     response_code,
                               GBytes * response_data,
                               gpointer check_user_data,
                               GError **error)
{
    return response_code == 200 && nmcs_utils_parse_get_full_line(response_data, "ami-id");
}

static void
_detect_get_meta_data_done_cb(GObject *source, GAsyncResult *result, gpointer user_data)
{
    gs_unref_object GTask *task     = user_data;
    gs_free_error GError *get_error = NULL;
    gs_free_error GError *error     = NULL;

    nm_http_client_poll_get_finish(NM_HTTP_CLIENT(source), result, NULL, NULL, &get_error);

    if (nm_utils_error_is_cancelled(get_error)) {
        g_task_return_error(task, g_steal_pointer(&get_error));
        return;
    }

    if (get_error) {
        nm_utils_error_set(&error,
                           NM_UTILS_ERROR_UNKNOWN,
                           "failure to get EC2 metadata: %s",
                           get_error->message);
        g_task_return_error(task, g_steal_pointer(&error));
        return;
    }

    g_task_return_boolean(task, TRUE);
}

static void
detect(NMCSProvider *provider, GTask *task)
{
    NMHttpClient *http_client;
    gs_free char *uri = NULL;

    http_client = nmcs_provider_get_http_client(provider);

    nm_http_client_poll_get(http_client,
                            (uri = _ec2_uri_concat("latest/meta-data/")),
                            HTTP_TIMEOUT_MS,
                            256 * 1024,
                            7000,
                            1000,
                            NULL,
                            g_task_get_cancellable(task),
                            _detect_get_meta_data_check_cb,
                            NULL,
                            _detect_get_meta_data_done_cb,
                            task);
}

/*****************************************************************************/

typedef struct {
    NMCSProviderGetConfigTaskData *get_config_data;
    GError *                       error;
    GCancellable *                 cancellable;
    gulong                         cancelled_id;
    guint                          n_pending;
} GetConfigIfaceData;

static void
_get_config_task_maybe_return(GetConfigIfaceData *iface_data, GError *error_take)
{
    NMCSProviderGetConfigTaskData *get_config_data = iface_data->get_config_data;

    if (error_take) {
        if (!iface_data->error)
            iface_data->error = error_take;
        else if (!nm_utils_error_is_cancelled(iface_data->error)
                 && nm_utils_error_is_cancelled(error_take)) {
            nm_clear_error(&iface_data->error);
            iface_data->error = error_take;
        } else
            g_error_free(error_take);
    }

    if (iface_data->n_pending > 0)
        return;

    nm_clear_g_cancellable_disconnect(g_task_get_cancellable(get_config_data->task),
                                      &iface_data->cancelled_id);

    nm_clear_g_cancellable(&iface_data->cancellable);

    if (iface_data->error) {
        if (nm_utils_error_is_cancelled(iface_data->error))
            _LOGD("get-config: cancelled");
        else
            _LOGD("get-config: failed: %s", iface_data->error->message);
        g_task_return_error(get_config_data->task, g_steal_pointer(&iface_data->error));
    } else {
        _LOGD("get-config: success");
        g_task_return_pointer(get_config_data->task,
                              g_hash_table_ref(get_config_data->result_dict),
                              (GDestroyNotify) g_hash_table_unref);
    }

    nm_g_slice_free(iface_data);
    g_object_unref(get_config_data->task);
}

static void
_get_config_fetch_done_cb(NMHttpClient *http_client,
                          GAsyncResult *result,
                          gpointer      user_data,
                          gboolean      is_local_ipv4)
{
    GetConfigIfaceData *iface_data;
    const char *        hwaddr           = NULL;
    gs_unref_bytes GBytes *response_data = NULL;
    gs_free_error GError *error          = NULL;

    nm_utils_user_data_unpack(user_data, &iface_data, &hwaddr);

    nm_http_client_poll_get_finish(http_client, result, NULL, &response_data, &error);

    if (!error) {
        NMCSProviderGetConfigIfaceData *config_iface_data;
        in_addr_t                       tmp_addr;
        int                             tmp_prefix;

        config_iface_data = g_hash_table_lookup(iface_data->get_config_data->result_dict, hwaddr);

        if (is_local_ipv4) {
            gs_free const char **s_addrs = NULL;
            gsize                i, len;

            s_addrs = nm_utils_strsplit_set_full(g_bytes_get_data(response_data, NULL),
                                                 "\n",
                                                 NM_UTILS_STRSPLIT_SET_FLAGS_STRSTRIP);
            len     = NM_PTRARRAY_LEN(s_addrs);

            nm_assert(!config_iface_data->has_ipv4s);
            nm_assert(!config_iface_data->ipv4s_arr);
            config_iface_data->has_ipv4s = TRUE;
            config_iface_data->ipv4s_len = 0;
            if (len > 0) {
                config_iface_data->ipv4s_arr = g_new(in_addr_t, len);

                for (i = 0; i < len; i++) {
                    if (nm_utils_parse_inaddr_bin(AF_INET, s_addrs[i], NULL, &tmp_addr))
                        config_iface_data->ipv4s_arr[config_iface_data->ipv4s_len++] = tmp_addr;
                }
            }
        } else {
            if (nm_utils_parse_inaddr_prefix_bin(AF_INET,
                                                 g_bytes_get_data(response_data, NULL),
                                                 NULL,
                                                 &tmp_addr,
                                                 &tmp_prefix)) {
                nm_assert(!config_iface_data->has_cidr);
                config_iface_data->has_cidr    = TRUE;
                config_iface_data->cidr_prefix = tmp_prefix;
                config_iface_data->cidr_addr   = tmp_addr;
            }
        }
    }

    iface_data->n_pending--;
    _get_config_task_maybe_return(iface_data, g_steal_pointer(&error));
}

static void
_get_config_fetch_done_cb_subnet_ipv4_cidr_block(GObject *     source,
                                                 GAsyncResult *result,
                                                 gpointer      user_data)
{
    _get_config_fetch_done_cb(NM_HTTP_CLIENT(source), result, user_data, FALSE);
}

static void
_get_config_fetch_done_cb_local_ipv4s(GObject *source, GAsyncResult *result, gpointer user_data)
{
    _get_config_fetch_done_cb(NM_HTTP_CLIENT(source), result, user_data, TRUE);
}

static void
_get_config_fetch_cancelled_cb(GObject *object, gpointer user_data)
{
    GetConfigIfaceData *iface_data = user_data;

    if (iface_data->cancelled_id == 0)
        return;

    nm_clear_g_signal_handler(g_task_get_cancellable(iface_data->get_config_data->task),
                              &iface_data->cancelled_id);
    _get_config_task_maybe_return(iface_data, nm_utils_error_new_cancelled(FALSE, NULL));
}

typedef struct {
    NMCSProviderGetConfigTaskData *get_config_data;
    GHashTable *                   response_parsed;
} GetConfigMetadataData;

typedef struct {
    gssize iface_idx;
    char   path[0];
} GetConfigMetadataMac;

static void
_get_config_metadata_ready_cb(GObject *source, GAsyncResult *result, gpointer user_data)
{
    GetConfigMetadataData *        metadata_data = user_data;
    GetConfigIfaceData *           iface_data;
    NMCSProviderGetConfigTaskData *get_config_data = metadata_data->get_config_data;
    gs_unref_hashtable GHashTable *response_parsed =
        g_steal_pointer(&metadata_data->response_parsed);
    gs_free_error GError *error = NULL;
    GCancellable *        cancellable;
    GetConfigMetadataMac *v_mac_data;
    const char *          v_hwaddr;
    GHashTableIter        h_iter;
    NMHttpClient *        http_client;

    nm_g_slice_free(metadata_data);

    nm_http_client_poll_get_finish(NM_HTTP_CLIENT(source), result, NULL, NULL, &error);

    iface_data  = g_slice_new(GetConfigIfaceData);
    *iface_data = (GetConfigIfaceData){
        .get_config_data = get_config_data,
        .n_pending       = 0,
    };

    if (nm_utils_error_is_cancelled(error)) {
        _get_config_task_maybe_return(iface_data, g_steal_pointer(&error));
        return;
    }

    /* We ignore errors. Only if we got no response at all, it's a problem.
	 * Otherwise, we proceed with whatever we could fetch. */
    if (!response_parsed) {
        _get_config_task_maybe_return(
            iface_data,
            nm_utils_error_new(NM_UTILS_ERROR_UNKNOWN, "meta data for interfaces not found"));
        return;
    }

    cancellable = g_task_get_cancellable(get_config_data->task);
    if (cancellable) {
        gulong cancelled_id;

        cancelled_id = g_cancellable_connect(cancellable,
                                             G_CALLBACK(_get_config_fetch_cancelled_cb),
                                             iface_data,
                                             NULL);
        if (cancelled_id == 0) {
            _get_config_task_maybe_return(iface_data, nm_utils_error_new_cancelled(FALSE, NULL));
            return;
        }

        iface_data->cancelled_id = cancelled_id;
    }

    iface_data->cancellable = g_cancellable_new();

    http_client = nmcs_provider_get_http_client(g_task_get_source_object(get_config_data->task));

    g_hash_table_iter_init(&h_iter, response_parsed);
    while (g_hash_table_iter_next(&h_iter, (gpointer *) &v_hwaddr, (gpointer *) &v_mac_data)) {
        NMCSProviderGetConfigIfaceData *config_iface_data;
        gs_free char *                  uri1 = NULL;
        gs_free char *                  uri2 = NULL;
        const char *                    hwaddr;

        if (!g_hash_table_lookup_extended(get_config_data->result_dict,
                                          v_hwaddr,
                                          (gpointer *) &hwaddr,
                                          (gpointer *) &config_iface_data)) {
            if (!get_config_data->any) {
                _LOGD("get-config: skip fetching meta data for %s (%s)",
                      v_hwaddr,
                      v_mac_data->path);
                continue;
            }
            config_iface_data = nmcs_provider_get_config_iface_data_new(FALSE);
            g_hash_table_insert(get_config_data->result_dict,
                                (char *) (hwaddr = g_strdup(v_hwaddr)),
                                config_iface_data);
        }

        nm_assert(config_iface_data->iface_idx == -1);
        config_iface_data->iface_idx = v_mac_data->iface_idx;

        _LOGD("get-config: start fetching meta data for #%" G_GSSIZE_FORMAT ", %s (%s)",
              config_iface_data->iface_idx,
              hwaddr,
              v_mac_data->path);

        iface_data->n_pending++;
        nm_http_client_poll_get(
            http_client,
            (uri1 = _ec2_uri_interfaces(v_mac_data->path,
                                        NM_STR_HAS_SUFFIX(v_mac_data->path, "/") ? "" : "/",
                                        "subnet-ipv4-cidr-block")),
            HTTP_TIMEOUT_MS,
            512 * 1024,
            10000,
            1000,
            NULL,
            iface_data->cancellable,
            NULL,
            NULL,
            _get_config_fetch_done_cb_subnet_ipv4_cidr_block,
            nm_utils_user_data_pack(iface_data, hwaddr));

        iface_data->n_pending++;
        nm_http_client_poll_get(
            http_client,
            (uri2 = _ec2_uri_interfaces(v_mac_data->path,
                                        NM_STR_HAS_SUFFIX(v_mac_data->path, "/") ? "" : "/",
                                        "local-ipv4s")),
            HTTP_TIMEOUT_MS,
            512 * 1024,
            10000,
            1000,
            NULL,
            iface_data->cancellable,
            NULL,
            NULL,
            _get_config_fetch_done_cb_local_ipv4s,
            nm_utils_user_data_pack(iface_data, hwaddr));
    }

    _get_config_task_maybe_return(iface_data, NULL);
}

static gboolean
_get_config_metadata_ready_check(long     response_code,
                                 GBytes * response_data,
                                 gpointer check_user_data,
                                 GError **error)
{
    GetConfigMetadataData *metadata_data           = check_user_data;
    gs_unref_hashtable GHashTable *response_parsed = NULL;
    const guint8 *                 r_data;
    const char *                   cur_line;
    gsize                          r_len;
    gsize                          cur_line_len;
    GHashTableIter                 h_iter;
    gboolean                       has_all;
    const char *                   c_hwaddr;
    gssize                         iface_idx_counter = 0;

    if (response_code != 200 || !response_data) {
        /* we wait longer. */
        return FALSE;
    }

    r_data = g_bytes_get_data(response_data, &r_len);
    /* NMHttpClient guarantees that there is a trailing NUL after the data. */
    nm_assert(r_data[r_len] == 0);

    while (nm_utils_parse_next_line((const char **) &r_data, &r_len, &cur_line, &cur_line_len)) {
        GetConfigMetadataMac *mac_data;
        char *                hwaddr;

        if (cur_line_len == 0)
            continue;

        /* Truncate the string. It's safe to do, because we own @response_data an it has an
		 * extra NUL character after the buffer. */
        ((char *) cur_line)[cur_line_len] = '\0';

        hwaddr = nmcs_utils_hwaddr_normalize(
            cur_line,
            cur_line[cur_line_len - 1u] == '/' ? (gssize)(cur_line_len - 1u) : -1);
        if (!hwaddr)
            continue;

        if (!response_parsed)
            response_parsed = g_hash_table_new_full(nm_str_hash, g_str_equal, g_free, g_free);

        mac_data            = g_malloc(sizeof(GetConfigMetadataMac) + 1u + cur_line_len);
        mac_data->iface_idx = iface_idx_counter++;
        memcpy(mac_data->path, cur_line, cur_line_len + 1u);

        g_hash_table_insert(response_parsed, hwaddr, mac_data);
    }

    has_all = TRUE;
    g_hash_table_iter_init(&h_iter, metadata_data->get_config_data->result_dict);
    while (g_hash_table_iter_next(&h_iter, (gpointer *) &c_hwaddr, NULL)) {
        if (!response_parsed || !g_hash_table_contains(response_parsed, c_hwaddr)) {
            has_all = FALSE;
            break;
        }
    }

    nm_clear_pointer(&metadata_data->response_parsed, g_hash_table_unref);
    metadata_data->response_parsed = g_steal_pointer(&response_parsed);
    return has_all;
}

static void
get_config(NMCSProvider *provider, NMCSProviderGetConfigTaskData *get_config_data)
{
    gs_free char *         uri = NULL;
    GetConfigMetadataData *metadata_data;

    metadata_data  = g_slice_new(GetConfigMetadataData);
    *metadata_data = (GetConfigMetadataData){
        .get_config_data = get_config_data,
    };

    /* First we fetch the "macs/". If the caller requested some particular
	 * MAC addresses, then we poll until we see them. They might not yet be
	 * around from the start...
	 */
    nm_http_client_poll_get(nmcs_provider_get_http_client(provider),
                            (uri = _ec2_uri_interfaces()),
                            HTTP_TIMEOUT_MS,
                            256 * 1024,
                            15000,
                            1000,
                            NULL,
                            g_task_get_cancellable(get_config_data->task),
                            _get_config_metadata_ready_check,
                            metadata_data,
                            _get_config_metadata_ready_cb,
                            metadata_data);
}

/*****************************************************************************/

static void
nmcs_provider_ec2_init(NMCSProviderEC2 *self)
{}

static void
nmcs_provider_ec2_class_init(NMCSProviderEC2Class *klass)
{
    NMCSProviderClass *provider_class = NMCS_PROVIDER_CLASS(klass);

    provider_class->_name                 = "ec2";
    provider_class->_env_provider_enabled = NMCS_ENV_VARIABLE("NM_CLOUD_SETUP_EC2");
    provider_class->detect                = detect;
    provider_class->get_config            = get_config;
}