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aws_imds_client.c
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aws_imds_client.c
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/**
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0.
*/
#include <aws/auth/aws_imds_client.h>
#include <aws/auth/private/credentials_utils.h>
#include <aws/common/clock.h>
#include <aws/common/condition_variable.h>
#include <aws/common/mutex.h>
#include <aws/common/string.h>
#include <aws/http/connection.h>
#include <aws/http/request_response.h>
#include <aws/http/status_code.h>
#include <aws/io/channel_bootstrap.h>
#include <aws/io/socket.h>
#include <ctype.h>
#include <aws/common/json.h>
#if defined(_MSC_VER)
# pragma warning(disable : 4204)
# pragma warning(disable : 4232)
#endif /* _MSC_VER */
/* instance role credentials body response is currently ~ 1300 characters + name length */
#define IMDS_RESPONSE_SIZE_INITIAL 2048
#define IMDS_RESPONSE_TOKEN_SIZE_INITIAL 64
#define IMDS_RESPONSE_SIZE_LIMIT 65535
#define IMDS_CONNECT_TIMEOUT_DEFAULT_IN_SECONDS 2
#define IMDS_DEFAULT_RETRIES 1
AWS_STATIC_STRING_FROM_LITERAL(s_imds_host, "169.254.169.254");
enum imds_token_state {
AWS_IMDS_TS_INVALID,
AWS_IMDS_TS_VALID,
AWS_IMDS_TS_UPDATE_IN_PROGRESS,
};
enum imds_token_copy_result {
/* Token is valid and copied to requester */
AWS_IMDS_TCR_SUCCESS,
/* Token is updating, so requester is added in waiting queue */
AWS_IMDS_TCR_WAITING_IN_QUEUE,
/* unexpected error,like mem allocation error */
AWS_IMDS_TCR_UNEXPECTED_ERROR,
};
struct imds_token_query {
struct aws_linked_list_node node;
void *user_data;
};
struct aws_imds_client {
struct aws_allocator *allocator;
struct aws_http_connection_manager *connection_manager;
struct aws_retry_strategy *retry_strategy;
const struct aws_auth_http_system_vtable *function_table;
struct aws_imds_client_shutdown_options shutdown_options;
/* will be set to true by default, means using IMDS V2 */
bool token_required;
struct aws_byte_buf cached_token;
uint64_t cached_token_expiration_timestamp;
enum imds_token_state token_state;
struct aws_linked_list pending_queries;
struct aws_mutex token_lock;
struct aws_condition_variable token_signal;
bool ec2_metadata_v1_disabled;
struct aws_atomic_var ref_count;
};
static void s_aws_imds_client_destroy(struct aws_imds_client *client) {
if (!client) {
return;
}
/**
* s_aws_imds_client_destroy is only called after all in-flight requests are finished,
* thus nothing is going to try and access retry_strategy again at this point.
*/
aws_retry_strategy_release(client->retry_strategy);
aws_condition_variable_clean_up(&client->token_signal);
aws_mutex_clean_up(&client->token_lock);
aws_byte_buf_clean_up(&client->cached_token);
client->function_table->aws_http_connection_manager_release(client->connection_manager);
/* freeing the client takes place in the shutdown callback below */
}
static void s_on_connection_manager_shutdown(void *user_data) {
struct aws_imds_client *client = user_data;
if (client && client->shutdown_options.shutdown_callback) {
client->shutdown_options.shutdown_callback(client->shutdown_options.shutdown_user_data);
}
aws_mem_release(client->allocator, client);
}
void aws_imds_client_release(struct aws_imds_client *client) {
if (!client) {
return;
}
size_t old_value = aws_atomic_fetch_sub(&client->ref_count, 1);
if (old_value == 1) {
s_aws_imds_client_destroy(client);
}
}
void aws_imds_client_acquire(struct aws_imds_client *client) {
aws_atomic_fetch_add(&client->ref_count, 1);
}
struct aws_imds_client *aws_imds_client_new(
struct aws_allocator *allocator,
const struct aws_imds_client_options *options) {
if (!options->bootstrap) {
AWS_LOGF_ERROR(AWS_LS_AUTH_CREDENTIALS_PROVIDER, "Client bootstrap is required for querying IMDS");
aws_raise_error(AWS_ERROR_INVALID_ARGUMENT);
return NULL;
}
struct aws_imds_client *client = aws_mem_calloc(allocator, 1, sizeof(struct aws_imds_client));
if (!client) {
return NULL;
}
if (aws_mutex_init(&client->token_lock)) {
goto on_error;
}
if (aws_condition_variable_init(&client->token_signal)) {
goto on_error;
}
if (aws_byte_buf_init(&client->cached_token, allocator, IMDS_RESPONSE_TOKEN_SIZE_INITIAL)) {
goto on_error;
}
aws_linked_list_init(&client->pending_queries);
aws_atomic_store_int(&client->ref_count, 1);
client->allocator = allocator;
client->function_table =
options->function_table ? options->function_table : g_aws_credentials_provider_http_function_table;
client->token_required = options->imds_version == IMDS_PROTOCOL_V1 ? false : true;
client->ec2_metadata_v1_disabled = options->ec2_metadata_v1_disabled;
client->shutdown_options = options->shutdown_options;
struct aws_socket_options socket_options;
AWS_ZERO_STRUCT(socket_options);
socket_options.type = AWS_SOCKET_STREAM;
socket_options.domain = AWS_SOCKET_IPV4;
socket_options.connect_timeout_ms = (uint32_t)aws_timestamp_convert(
IMDS_CONNECT_TIMEOUT_DEFAULT_IN_SECONDS, AWS_TIMESTAMP_SECS, AWS_TIMESTAMP_MILLIS, NULL);
struct aws_http_connection_manager_options manager_options;
AWS_ZERO_STRUCT(manager_options);
manager_options.bootstrap = options->bootstrap;
manager_options.initial_window_size = IMDS_RESPONSE_SIZE_LIMIT;
manager_options.socket_options = &socket_options;
manager_options.tls_connection_options = NULL;
manager_options.host = aws_byte_cursor_from_string(s_imds_host);
manager_options.port = 80;
manager_options.max_connections = 10;
manager_options.shutdown_complete_callback = s_on_connection_manager_shutdown;
manager_options.shutdown_complete_user_data = client;
client->connection_manager = client->function_table->aws_http_connection_manager_new(allocator, &manager_options);
if (!client->connection_manager) {
goto on_error;
}
if (options->retry_strategy) {
client->retry_strategy = options->retry_strategy;
aws_retry_strategy_acquire(client->retry_strategy);
} else {
struct aws_exponential_backoff_retry_options retry_options = {
.el_group = options->bootstrap->event_loop_group,
.max_retries = IMDS_DEFAULT_RETRIES,
};
/* exponential backoff is plenty here. We're hitting a local endpoint and do not run the risk of bringing
* down more than the local VM. */
client->retry_strategy = aws_retry_strategy_new_exponential_backoff(allocator, &retry_options);
}
if (!client->retry_strategy) {
goto on_error;
}
return client;
on_error:
s_aws_imds_client_destroy(client);
return NULL;
}
/*
* Tracking structure for each outstanding async query to an imds client
*/
struct imds_user_data {
/* immutable post-creation */
struct aws_allocator *allocator;
struct aws_imds_client *client;
aws_imds_client_on_get_resource_callback_fn *original_callback;
void *original_user_data;
/* mutable */
struct aws_http_connection *connection;
struct aws_http_message *request;
struct aws_byte_buf current_result;
struct aws_byte_buf imds_token;
struct aws_string *resource_path;
struct aws_retry_token *retry_token;
/*
* initial value is copy of client->token_required,
* will be adapted according to response.
*/
bool imds_token_required;
/* Indicate the request is a fallback from a failure call. */
bool is_fallback_request;
bool is_imds_token_request;
bool ec2_metadata_v1_disabled;
int status_code;
int error_code;
struct aws_atomic_var ref_count;
};
static void s_user_data_destroy(struct imds_user_data *user_data) {
if (user_data == NULL) {
return;
}
struct aws_imds_client *client = user_data->client;
if (user_data->connection) {
client->function_table->aws_http_connection_manager_release_connection(
client->connection_manager, user_data->connection);
}
aws_byte_buf_clean_up(&user_data->current_result);
aws_byte_buf_clean_up(&user_data->imds_token);
aws_string_destroy(user_data->resource_path);
if (user_data->request) {
aws_http_message_destroy(user_data->request);
}
aws_retry_token_release(user_data->retry_token);
aws_imds_client_release(client);
aws_mem_release(user_data->allocator, user_data);
}
static struct imds_user_data *s_user_data_new(
struct aws_imds_client *client,
struct aws_byte_cursor resource_path,
aws_imds_client_on_get_resource_callback_fn *callback,
void *user_data) {
struct imds_user_data *wrapped_user_data = aws_mem_calloc(client->allocator, 1, sizeof(struct imds_user_data));
if (!wrapped_user_data) {
goto on_error;
}
wrapped_user_data->allocator = client->allocator;
wrapped_user_data->client = client;
aws_imds_client_acquire(client);
wrapped_user_data->original_user_data = user_data;
wrapped_user_data->original_callback = callback;
if (aws_byte_buf_init(&wrapped_user_data->current_result, client->allocator, IMDS_RESPONSE_SIZE_INITIAL)) {
goto on_error;
}
if (aws_byte_buf_init(&wrapped_user_data->imds_token, client->allocator, IMDS_RESPONSE_TOKEN_SIZE_INITIAL)) {
goto on_error;
}
wrapped_user_data->resource_path =
aws_string_new_from_array(client->allocator, resource_path.ptr, resource_path.len);
if (!wrapped_user_data->resource_path) {
goto on_error;
}
wrapped_user_data->imds_token_required = client->token_required;
wrapped_user_data->ec2_metadata_v1_disabled = client->ec2_metadata_v1_disabled;
aws_atomic_store_int(&wrapped_user_data->ref_count, 1);
return wrapped_user_data;
on_error:
s_user_data_destroy(wrapped_user_data);
return NULL;
}
static void s_user_data_acquire(struct imds_user_data *user_data) {
if (user_data == NULL) {
return;
}
aws_atomic_fetch_add(&user_data->ref_count, 1);
}
static void s_user_data_release(struct imds_user_data *user_data) {
if (!user_data) {
return;
}
size_t old_value = aws_atomic_fetch_sub(&user_data->ref_count, 1);
if (old_value == 1) {
s_user_data_destroy(user_data);
}
}
static void s_reset_scratch_user_data(struct imds_user_data *user_data) {
user_data->current_result.len = 0;
user_data->status_code = 0;
if (user_data->request) {
aws_http_message_destroy(user_data->request);
user_data->request = NULL;
}
}
static enum imds_token_copy_result s_copy_token_safely(struct imds_user_data *user_data);
static void s_update_token_safely(
struct aws_imds_client *client,
struct aws_byte_buf *token,
bool token_required,
uint64_t expire_timestamp);
static void s_query_complete(struct imds_user_data *user_data);
static void s_on_acquire_connection(struct aws_http_connection *connection, int error_code, void *user_data);
static void s_on_retry_token_acquired(struct aws_retry_strategy *, int, struct aws_retry_token *, void *);
static int s_on_incoming_body_fn(struct aws_http_stream *stream, const struct aws_byte_cursor *data, void *user_data) {
(void)stream;
(void)data;
struct imds_user_data *imds_user_data = user_data;
struct aws_imds_client *client = imds_user_data->client;
if (data->len + imds_user_data->current_result.len > IMDS_RESPONSE_SIZE_LIMIT) {
client->function_table->aws_http_connection_close(imds_user_data->connection);
AWS_LOGF_ERROR(
AWS_LS_IMDS_CLIENT, "(id=%p) IMDS client query response exceeded maximum allowed length", (void *)client);
return AWS_OP_ERR;
}
if (aws_byte_buf_append_dynamic(&imds_user_data->current_result, data)) {
client->function_table->aws_http_connection_close(imds_user_data->connection);
AWS_LOGF_ERROR(AWS_LS_IMDS_CLIENT, "(id=%p) IMDS client query error appending response", (void *)client);
return AWS_OP_ERR;
}
return AWS_OP_SUCCESS;
}
static int s_on_incoming_headers_fn(
struct aws_http_stream *stream,
enum aws_http_header_block header_block,
const struct aws_http_header *header_array,
size_t num_headers,
void *user_data) {
(void)header_array;
(void)num_headers;
if (header_block != AWS_HTTP_HEADER_BLOCK_MAIN) {
return AWS_OP_SUCCESS;
}
struct imds_user_data *imds_user_data = user_data;
struct aws_imds_client *client = imds_user_data->client;
if (header_block == AWS_HTTP_HEADER_BLOCK_MAIN) {
if (imds_user_data->status_code == 0) {
if (client->function_table->aws_http_stream_get_incoming_response_status(
stream, &imds_user_data->status_code)) {
AWS_LOGF_ERROR(
AWS_LS_IMDS_CLIENT, "(id=%p) IMDS client failed to get http status code", (void *)client);
return AWS_OP_ERR;
}
AWS_LOGF_DEBUG(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client query received http status code %d for requester %p.",
(void *)client,
imds_user_data->status_code,
user_data);
}
}
return AWS_OP_SUCCESS;
}
AWS_STATIC_STRING_FROM_LITERAL(s_imds_host_header, "Host");
AWS_STATIC_STRING_FROM_LITERAL(s_imds_accept_header, "Accept");
AWS_STATIC_STRING_FROM_LITERAL(s_imds_accept_header_value, "*/*");
AWS_STATIC_STRING_FROM_LITERAL(s_imds_user_agent_header, "User-Agent");
AWS_STATIC_STRING_FROM_LITERAL(s_imds_user_agent_header_value, "aws-sdk-crt/aws-imds-client");
AWS_STATIC_STRING_FROM_LITERAL(s_imds_h1_0_keep_alive_header, "Connection");
AWS_STATIC_STRING_FROM_LITERAL(s_imds_h1_0_keep_alive_header_value, "keep-alive");
AWS_STATIC_STRING_FROM_LITERAL(s_imds_token_resource_path, "/latest/api/token");
AWS_STATIC_STRING_FROM_LITERAL(s_imds_token_ttl_header, "x-aws-ec2-metadata-token-ttl-seconds");
AWS_STATIC_STRING_FROM_LITERAL(s_imds_token_header, "x-aws-ec2-metadata-token");
AWS_STATIC_STRING_FROM_LITERAL(s_imds_token_ttl_default_value, "21600");
/* s_imds_token_ttl_default_value - 5secs for refreshing the cached token */
static const uint64_t s_imds_token_ttl_secs = 21595;
static void s_on_stream_complete_fn(struct aws_http_stream *stream, int error_code, void *user_data);
static int s_make_imds_http_query(
struct imds_user_data *user_data,
const struct aws_byte_cursor *verb,
const struct aws_byte_cursor *uri,
const struct aws_http_header *headers,
size_t header_count) {
AWS_FATAL_ASSERT(user_data->connection);
struct aws_imds_client *client = user_data->client;
struct aws_http_stream *stream = NULL;
struct aws_http_message *request = aws_http_message_new_request(user_data->allocator);
if (request == NULL) {
return AWS_OP_ERR;
}
if (headers && aws_http_message_add_header_array(request, headers, header_count)) {
goto on_error;
}
struct aws_http_header host_header = {
.name = aws_byte_cursor_from_string(s_imds_host_header),
.value = aws_byte_cursor_from_string(s_imds_host),
};
if (aws_http_message_add_header(request, host_header)) {
goto on_error;
}
struct aws_http_header accept_header = {
.name = aws_byte_cursor_from_string(s_imds_accept_header),
.value = aws_byte_cursor_from_string(s_imds_accept_header_value),
};
if (aws_http_message_add_header(request, accept_header)) {
goto on_error;
}
struct aws_http_header user_agent_header = {
.name = aws_byte_cursor_from_string(s_imds_user_agent_header),
.value = aws_byte_cursor_from_string(s_imds_user_agent_header_value),
};
if (aws_http_message_add_header(request, user_agent_header)) {
goto on_error;
}
struct aws_http_header keep_alive_header = {
.name = aws_byte_cursor_from_string(s_imds_h1_0_keep_alive_header),
.value = aws_byte_cursor_from_string(s_imds_h1_0_keep_alive_header_value),
};
if (aws_http_message_add_header(request, keep_alive_header)) {
goto on_error;
}
if (aws_http_message_set_request_method(request, *verb)) {
goto on_error;
}
if (aws_http_message_set_request_path(request, *uri)) {
goto on_error;
}
user_data->request = request;
struct aws_http_make_request_options request_options = {
.self_size = sizeof(request_options),
.on_response_headers = s_on_incoming_headers_fn,
.on_response_header_block_done = NULL,
.on_response_body = s_on_incoming_body_fn,
.on_complete = s_on_stream_complete_fn,
.response_first_byte_timeout_ms = 1000,
.user_data = user_data,
.request = request,
};
/* for test with mocking http stack where make request finishes
immediately and releases client before stream activate call */
s_user_data_acquire(user_data);
stream = client->function_table->aws_http_connection_make_request(user_data->connection, &request_options);
if (!stream || client->function_table->aws_http_stream_activate(stream)) {
goto on_error;
}
s_user_data_release(user_data);
return AWS_OP_SUCCESS;
on_error:
user_data->client->function_table->aws_http_stream_release(stream);
aws_http_message_destroy(request);
user_data->request = NULL;
s_user_data_release(user_data);
return AWS_OP_ERR;
}
/*
* Process the http response from the token put request.
*/
static void s_client_on_token_response(struct imds_user_data *user_data) {
/* Gets 400 means token is required but the request itself failed. */
if (user_data->status_code == AWS_HTTP_STATUS_CODE_400_BAD_REQUEST) {
s_update_token_safely(user_data->client, NULL, true, 0 /*expire_timestamp*/);
return;
}
if (user_data->status_code == AWS_HTTP_STATUS_CODE_200_OK && user_data->current_result.len != 0) {
AWS_LOGF_DEBUG(AWS_LS_IMDS_CLIENT, "(id=%p) IMDS client has fetched the token", (void *)user_data->client);
struct aws_byte_cursor cursor = aws_byte_cursor_from_buf(&(user_data->current_result));
aws_byte_cursor_trim_pred(&cursor, aws_char_is_space);
aws_byte_buf_reset(&user_data->imds_token, true /*zero contents*/);
if (aws_byte_buf_append_and_update(&user_data->imds_token, &cursor)) {
s_update_token_safely(user_data->client, NULL /*token*/, true /*token_required*/, 0 /*expire_timestamp*/);
return;
}
/* The token was ALWAYS last for 6 hours, 21600 secs. Use current timestamp plus 21595 secs as the expiration
* timestamp for current token */
uint64_t current = 0;
user_data->client->function_table->aws_high_res_clock_get_ticks(¤t);
uint64_t expire_timestamp = aws_add_u64_saturating(
current, aws_timestamp_convert(s_imds_token_ttl_secs, AWS_TIMESTAMP_SECS, AWS_TIMESTAMP_NANOS, NULL));
AWS_ASSERT(cursor.len != 0);
s_update_token_safely(user_data->client, &user_data->imds_token, true /*token_required*/, expire_timestamp);
} else if (user_data->ec2_metadata_v1_disabled) {
AWS_LOGF_DEBUG(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client failed to fetch token for requester %p, and fall back to v1 is disabled."
"Received response status code: %d",
(void *)user_data->client,
(void *)user_data,
user_data->status_code);
s_update_token_safely(user_data->client, NULL /*token*/, true /*token_required*/, 0 /*expire_timestamp*/);
} else {
/* Request failed; falling back to insecure request.
* TODO: The retryable error (503 throttle) will also fall back to v1. Instead, we should just resend the token
* request.
*/
AWS_LOGF_DEBUG(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client failed to fetch token for requester %p, fall back to v1 for the same "
"requester. Received response status code: %d",
(void *)user_data->client,
(void *)user_data,
user_data->status_code);
s_update_token_safely(user_data->client, NULL /*token*/, false /* token_required*/, 0 /*expire_timestamp*/);
}
}
static int s_client_start_query_token(struct aws_imds_client *client) {
struct imds_user_data *user_data = s_user_data_new(client, aws_byte_cursor_from_c_str(""), NULL, (void *)client);
if (!user_data) {
AWS_LOGF_ERROR(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client failed to query token with error: %s.",
(void *)client,
aws_error_str(aws_last_error()));
return AWS_OP_ERR;
}
user_data->is_imds_token_request = true;
if (aws_retry_strategy_acquire_retry_token(
client->retry_strategy, NULL, s_on_retry_token_acquired, user_data, 100)) {
s_user_data_release(user_data);
return AWS_OP_ERR;
}
return AWS_OP_SUCCESS;
}
/* Make an http request to put a ttl and hopefully get a token back. */
static void s_client_do_query_token(struct imds_user_data *user_data) {
/* start query token for imds client */
struct aws_byte_cursor uri = aws_byte_cursor_from_string(s_imds_token_resource_path);
/* Hard-coded 6 hour TTL for the token. */
struct aws_http_header token_ttl_header = {
.name = aws_byte_cursor_from_string(s_imds_token_ttl_header),
.value = aws_byte_cursor_from_string(s_imds_token_ttl_default_value),
};
struct aws_http_header headers[] = {
token_ttl_header,
};
struct aws_byte_cursor verb = aws_byte_cursor_from_c_str("PUT");
if (s_make_imds_http_query(user_data, &verb, &uri, headers, AWS_ARRAY_SIZE(headers))) {
user_data->error_code = aws_last_error();
if (user_data->error_code == AWS_ERROR_SUCCESS) {
user_data->error_code = AWS_ERROR_UNKNOWN;
}
s_query_complete(user_data);
}
}
/*
* Make the http request to fetch the resource
*/
static void s_do_query_resource(struct imds_user_data *user_data) {
struct aws_http_header token_header = {
.name = aws_byte_cursor_from_string(s_imds_token_header),
.value = aws_byte_cursor_from_buf(&user_data->imds_token),
};
struct aws_http_header headers[] = {
token_header,
};
size_t headers_count = 0;
struct aws_http_header *headers_array_ptr = NULL;
if (user_data->imds_token_required) {
headers_count = 1;
headers_array_ptr = headers;
}
struct aws_byte_cursor verb = aws_byte_cursor_from_c_str("GET");
struct aws_byte_cursor path_cursor = aws_byte_cursor_from_string(user_data->resource_path);
if (s_make_imds_http_query(user_data, &verb, &path_cursor, headers_array_ptr, headers_count)) {
user_data->error_code = aws_last_error();
if (user_data->error_code == AWS_ERROR_SUCCESS) {
user_data->error_code = AWS_ERROR_UNKNOWN;
}
s_query_complete(user_data);
}
}
int s_get_resource_async_with_imds_token(struct imds_user_data *user_data);
static void s_query_complete(struct imds_user_data *user_data) {
if (user_data->is_imds_token_request) {
s_client_on_token_response(user_data);
s_user_data_release(user_data);
return;
}
if (user_data->status_code == AWS_HTTP_STATUS_CODE_401_UNAUTHORIZED) {
struct aws_imds_client *client = user_data->client;
aws_mutex_lock(&client->token_lock);
if (aws_byte_buf_eq(&user_data->imds_token, &client->cached_token)) {
/* If the token used matches the cached token, that means the cached token is invalid. */
client->token_state = AWS_IMDS_TS_INVALID;
AWS_LOGF_DEBUG(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client's cached token is invalidated by requester %p.",
(void *)client,
(void *)user_data);
}
/* let following requests use token as it's required. */
client->token_required = true;
aws_mutex_unlock(&client->token_lock);
if (!user_data->imds_token_required && !user_data->is_fallback_request) {
AWS_LOGF_DEBUG(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client failed to fetch resource via V1, try to use V2. requester %p.",
(void *)user_data->client,
(void *)user_data);
/* V1 request, fallback to V2 and try again. */
s_reset_scratch_user_data(user_data);
user_data->is_fallback_request = true;
aws_retry_token_release(user_data->retry_token);
/* Try V2 now. */
if (s_get_resource_async_with_imds_token(user_data)) {
s_user_data_release(user_data);
}
return;
} else {
/* Not retirable error. */
AWS_LOGF_ERROR(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client failed to fetch resource. Server response 401 UNAUTHORIZED. requester %p.",
(void *)user_data->client,
(void *)user_data);
user_data->error_code = AWS_AUTH_IMDS_CLIENT_SOURCE_FAILURE;
}
}
/* TODO: if server sent out error, we will still report as succeed with the error body received from server. */
/* TODO: retry for 503 throttle. */
user_data->original_callback(
user_data->error_code ? NULL : &user_data->current_result,
user_data->error_code,
user_data->original_user_data);
s_user_data_release(user_data);
}
static void s_on_acquire_connection(struct aws_http_connection *connection, int error_code, void *user_data) {
struct imds_user_data *imds_user_data = user_data;
imds_user_data->connection = connection;
if (!connection) {
AWS_LOGF_WARN(
AWS_LS_IMDS_CLIENT,
"id=%p: IMDS Client failed to acquire a connection, error code %d(%s)",
(void *)imds_user_data->client,
error_code,
aws_error_str(error_code));
imds_user_data->error_code = error_code;
s_query_complete(imds_user_data);
return;
}
if (imds_user_data->is_imds_token_request) {
s_client_do_query_token(imds_user_data);
} else {
s_do_query_resource(imds_user_data);
}
}
static void s_on_retry_ready(struct aws_retry_token *token, int error_code, void *user_data) {
(void)token;
struct imds_user_data *imds_user_data = user_data;
struct aws_imds_client *client = imds_user_data->client;
if (!error_code) {
client->function_table->aws_http_connection_manager_acquire_connection(
client->connection_manager, s_on_acquire_connection, user_data);
} else {
AWS_LOGF_WARN(
AWS_LS_IMDS_CLIENT,
"id=%p: IMDS Client failed to retry the request with error code %d(%s)",
(void *)client,
error_code,
aws_error_str(error_code));
imds_user_data->error_code = error_code;
s_query_complete(imds_user_data);
}
}
static void s_on_stream_complete_fn(struct aws_http_stream *stream, int error_code, void *user_data) {
struct imds_user_data *imds_user_data = user_data;
struct aws_imds_client *client = imds_user_data->client;
aws_http_message_destroy(imds_user_data->request);
imds_user_data->request = NULL;
imds_user_data->connection = NULL;
struct aws_http_connection *connection = client->function_table->aws_http_stream_get_connection(stream);
client->function_table->aws_http_stream_release(stream);
client->function_table->aws_http_connection_manager_release_connection(client->connection_manager, connection);
/* on encountering error, see if we could try again */
/* TODO: check the status code as well? */
if (error_code) {
AWS_LOGF_WARN(
AWS_LS_IMDS_CLIENT,
"id=%p: Stream completed with error code %d(%s)",
(void *)client,
error_code,
aws_error_str(error_code));
if (!aws_retry_strategy_schedule_retry(
imds_user_data->retry_token, AWS_RETRY_ERROR_TYPE_TRANSIENT, s_on_retry_ready, user_data)) {
AWS_LOGF_DEBUG(
AWS_LS_IMDS_CLIENT,
"id=%p: Stream completed, retrying the last request on a new connection.",
(void *)client);
return;
} else {
AWS_LOGF_ERROR(AWS_LS_IMDS_CLIENT, "id=%p: Stream completed, retries have been exhausted.", (void *)client);
imds_user_data->error_code = error_code;
}
} else if (aws_retry_token_record_success(imds_user_data->retry_token)) {
AWS_LOGF_ERROR(
AWS_LS_IMDS_CLIENT,
"id=%p: Error while recording successful retry: %s",
(void *)client,
aws_error_str(aws_last_error()));
}
s_query_complete(imds_user_data);
}
static void s_on_retry_token_acquired(
struct aws_retry_strategy *strategy,
int error_code,
struct aws_retry_token *token,
void *user_data) {
(void)strategy;
struct imds_user_data *imds_user_data = user_data;
struct aws_imds_client *client = imds_user_data->client;
if (!error_code) {
AWS_LOGF_DEBUG(AWS_LS_IMDS_CLIENT, "id=%p: IMDS Client successfully acquired retry token.", (void *)client);
imds_user_data->retry_token = token;
client->function_table->aws_http_connection_manager_acquire_connection(
client->connection_manager, s_on_acquire_connection, imds_user_data);
} else {
AWS_LOGF_WARN(
AWS_LS_IMDS_CLIENT,
"id=%p: IMDS Client failed to acquire retry token, error code %d(%s)",
(void *)client,
error_code,
aws_error_str(error_code));
imds_user_data->error_code = error_code;
s_query_complete(imds_user_data);
}
}
static void s_complete_pending_queries(
struct aws_imds_client *client,
struct aws_linked_list *queries,
bool token_required,
struct aws_byte_buf *token) {
/* poll swapped out pending queries if there is any */
while (!aws_linked_list_empty(queries)) {
struct aws_linked_list_node *node = aws_linked_list_pop_back(queries);
struct imds_token_query *query = AWS_CONTAINER_OF(node, struct imds_token_query, node);
struct imds_user_data *requester = query->user_data;
aws_mem_release(client->allocator, query);
bool should_continue = true;
if (requester->imds_token_required && !token_required) {
if (requester->is_fallback_request) {
AWS_LOGF_ERROR(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client failed to fetch resource without token, and also failed to fetch token. "
"requester %p.",
(void *)requester->client,
(void *)requester);
requester->error_code = AWS_AUTH_IMDS_CLIENT_SOURCE_FAILURE;
should_continue = false;
} else {
AWS_LOGF_DEBUG(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client failed to fetch token, fallback to v1. requester %p.",
(void *)requester->client,
(void *)requester);
requester->is_fallback_request = true;
}
}
requester->imds_token_required = token_required;
if (token) {
aws_byte_buf_reset(&requester->imds_token, true);
struct aws_byte_cursor cursor = aws_byte_cursor_from_buf(token);
if (aws_byte_buf_append_dynamic(&requester->imds_token, &cursor)) {
AWS_LOGF_ERROR(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client failed to copy IMDS token for requester %p.",
(void *)client,
(void *)requester);
should_continue = false;
}
} else if (token_required) {
requester->error_code = AWS_AUTH_IMDS_CLIENT_SOURCE_FAILURE;
should_continue = false;
}
if (should_continue && aws_retry_strategy_acquire_retry_token(
client->retry_strategy, NULL, s_on_retry_token_acquired, requester, 100)) {
AWS_LOGF_ERROR(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client failed to allocate retry token for requester %p to send resource request.",
(void *)client,
(void *)requester);
should_continue = false;
}
if (!should_continue) {
if (requester->error_code == AWS_ERROR_SUCCESS) {
requester->error_code = aws_last_error() == AWS_ERROR_SUCCESS ? AWS_ERROR_UNKNOWN : aws_last_error();
}
s_query_complete(requester);
}
}
}
static enum imds_token_copy_result s_copy_token_safely(struct imds_user_data *user_data) {
struct aws_imds_client *client = user_data->client;
enum imds_token_copy_result ret = AWS_IMDS_TCR_UNEXPECTED_ERROR;
struct aws_linked_list pending_queries;
aws_linked_list_init(&pending_queries);
uint64_t current = 0;
user_data->client->function_table->aws_high_res_clock_get_ticks(¤t);
aws_mutex_lock(&client->token_lock);
if (client->token_state == AWS_IMDS_TS_VALID) {
if (current > client->cached_token_expiration_timestamp) {
/* The cached token expired. Switch the state */
client->token_state = AWS_IMDS_TS_INVALID;
AWS_LOGF_DEBUG(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client's cached token expired. Fetching new token for requester %p.",
(void *)client,
(void *)user_data);
} else {
aws_byte_buf_reset(&user_data->imds_token, true);
struct aws_byte_cursor cursor = aws_byte_cursor_from_buf(&client->cached_token);
if (aws_byte_buf_append_dynamic(&user_data->imds_token, &cursor)) {
ret = AWS_IMDS_TCR_UNEXPECTED_ERROR;
} else {
ret = AWS_IMDS_TCR_SUCCESS;
}
}
}
if (client->token_state != AWS_IMDS_TS_VALID) {
ret = AWS_IMDS_TCR_WAITING_IN_QUEUE;
struct imds_token_query *query = aws_mem_calloc(client->allocator, 1, sizeof(struct imds_token_query));
query->user_data = user_data;
aws_linked_list_push_back(&client->pending_queries, &query->node);
if (client->token_state == AWS_IMDS_TS_INVALID) {
if (s_client_start_query_token(client)) {
ret = AWS_IMDS_TCR_UNEXPECTED_ERROR;
aws_linked_list_swap_contents(&pending_queries, &client->pending_queries);
} else {
client->token_state = AWS_IMDS_TS_UPDATE_IN_PROGRESS;
}
}
}
aws_mutex_unlock(&client->token_lock);
s_complete_pending_queries(client, &pending_queries, true, NULL);
switch (ret) {
case AWS_IMDS_TCR_SUCCESS:
AWS_LOGF_DEBUG(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client copied token to requester %p successfully.",
(void *)client,
(void *)user_data);
break;
case AWS_IMDS_TCR_WAITING_IN_QUEUE:
AWS_LOGF_DEBUG(
AWS_LS_IMDS_CLIENT, "(id=%p) IMDS client's token is invalid and is now updating.", (void *)client);
break;
case AWS_IMDS_TCR_UNEXPECTED_ERROR:
AWS_LOGF_DEBUG(
AWS_LS_IMDS_CLIENT,
"(id=%p) IMDS client encountered unexpected error when processing token query for requester %p, error: "
"%s.",
(void *)client,
(void *)user_data,
aws_error_str(aws_last_error()));
break;
}
return ret;
}
/**
* Once a requseter returns from token request, it should call this function to unblock all other
* waiting requesters. When the token parameter is NULL, means the token request failed. Now we need
* a new requester to acquire the token again.
*/
static void s_update_token_safely(
struct aws_imds_client *client,
struct aws_byte_buf *token,
bool token_required,
uint64_t expire_timestamp) {
AWS_FATAL_ASSERT(client);
bool updated = false;
struct aws_linked_list pending_queries;
aws_linked_list_init(&pending_queries);
aws_mutex_lock(&client->token_lock);
client->token_required = token_required;
if (token) {
aws_byte_buf_reset(&client->cached_token, true);
struct aws_byte_cursor cursor = aws_byte_cursor_from_buf(token);
if (aws_byte_buf_append_dynamic(&client->cached_token, &cursor) == AWS_OP_SUCCESS) {
client->token_state = AWS_IMDS_TS_VALID;
client->cached_token_expiration_timestamp = expire_timestamp;
updated = true;
}
} else {
client->token_state = AWS_IMDS_TS_INVALID;
}
aws_linked_list_swap_contents(&pending_queries, &client->pending_queries);
aws_mutex_unlock(&client->token_lock);
s_complete_pending_queries(client, &pending_queries, token_required, token);
if (updated) {
AWS_LOGF_DEBUG(
AWS_LS_IMDS_CLIENT, "(id=%p) IMDS client updated the cached token successfully.", (void *)client);
} else {
AWS_LOGF_ERROR(AWS_LS_IMDS_CLIENT, "(id=%p) IMDS client failed to update the token from IMDS.", (void *)client);
}
}
int s_get_resource_async_with_imds_token(struct imds_user_data *user_data) {
enum imds_token_copy_result res = s_copy_token_safely(user_data);
if (res == AWS_IMDS_TCR_UNEXPECTED_ERROR) {