H2 setting frame (#206)

* Setting frames in connection

* bug_fix

* Debug

* decoder_settings

* encoder_settings

* Unit_test_built

* clang format

* consistance between code

* delete unused value

* add buffer_list for settings

* windows cannot build fuzz test..

* clang format

* update based on mike's comments

* clang format

Co-authored-by: Dengke Tang <dengket@amazon.com>

Author: TingDaoK

include/aws/http/private/h2_connection.h

@@ -42,6 +42,11 @@ struct aws_h2_connection {
 
         bool is_outgoing_frames_task_active;
 
+        /* Settings received from peer, which restricts the message to send */
+        uint32_t settings_peer[AWS_H2_SETTINGS_END_RANGE];
+        /* My settings to send/sent to peer, which affects the decoding */
+        uint32_t settings_self[AWS_H2_SETTINGS_END_RANGE];
+
         /* Maps stream-id to aws_h2_stream*.
          * Contains all streams in the open, reserved, and half-closed states (terms from RFC-7540 5.1).
          * Once a stream enters closed state, it is removed from this map. */

include/aws/http/private/h2_decoder.h

@@ -75,11 +75,8 @@ struct aws_h2_decoder_vtable {
     /* Called once for SETTINGS frame with ACK flag */
     int (*on_settings_ack)(void *userdata);
 
-    /* For SETTINGS frame (no ACK flag set): _begin() is called, then 0+ _i() calls, then _end().
-     * No other decoder callbacks will occur in this time. */
-    int (*on_settings_begin)(void *userdata);
-    int (*on_settings_i)(uint16_t setting_id, uint32_t value, void *userdata);
-    int (*on_settings_end)(void *userdata);
+    /* Called once for SETTINGS frame, without ACK flag */
+    int (*on_settings)(const struct aws_h2_frame_setting *settings_array, size_t num_settings, void *userdata);
 
     /* For GOAWAY frame: _begin() is called, then 0+ _i() calls, then _end().
      * No other decoder callbacks will occur in this time. */
@@ -114,6 +111,10 @@ AWS_HTTP_API struct aws_h2_decoder *aws_h2_decoder_new(struct aws_h2_decoder_par
 AWS_HTTP_API void aws_h2_decoder_destroy(struct aws_h2_decoder *decoder);
 AWS_HTTP_API int aws_h2_decode(struct aws_h2_decoder *decoder, struct aws_byte_cursor *data);
 
+AWS_HTTP_API void aws_h2_decoder_set_setting_header_table_size(struct aws_h2_decoder *decoder, uint32_t data);
+AWS_HTTP_API void aws_h2_decoder_set_setting_enable_push(struct aws_h2_decoder *decoder, uint32_t data);
+AWS_HTTP_API void aws_h2_decoder_set_setting_max_frame_size(struct aws_h2_decoder *decoder, uint32_t data);
+
 AWS_EXTERN_C_END
 
 #endif /* AWS_HTTP_H2_DECODER_H */

include/aws/http/private/h2_frames.h

@@ -133,6 +133,15 @@ struct aws_h2_frame_encoder {
     const void *logging_id;
     struct aws_hpack_context *hpack;
     struct aws_h2_frame *current_frame;
+
+    /* Settings for frame encoder, which is based on the settings received from peer */
+    struct {
+        /* the maximum size of the header compression table used to decode header blocks */
+        uint32_t header_table_size;
+        /*  the size of the largest frame payload */
+        uint32_t max_frame_size;
+    } settings;
+
     bool has_errored;
 };
 
@@ -272,6 +281,11 @@ struct aws_h2_frame *aws_h2_frame_new_window_update(
     uint32_t stream_id,
     uint32_t window_size_increment);
 
+AWS_HTTP_API void aws_h2_frame_encoder_set_setting_header_table_size(
+    struct aws_h2_frame_encoder *encoder,
+    uint32_t data);
+AWS_HTTP_API void aws_h2_frame_encoder_set_setting_max_frame_size(struct aws_h2_frame_encoder *encoder, uint32_t data);
+
 AWS_EXTERN_C_END
 
 #endif /* AWS_HTTP_H2_FRAMES_H */

source/h2_connection.c

@@ -62,6 +62,11 @@ static void s_cross_thread_work_task(struct aws_channel_task *task, void *arg, e
 static void s_outgoing_frames_task(struct aws_channel_task *task, void *arg, enum aws_task_status status);
 
 static int s_decoder_on_ping(uint8_t opaque_data[AWS_H2_PING_DATA_SIZE], void *userdata);
+static int s_decoder_on_settings(
+    const struct aws_h2_frame_setting *settings_array,
+    size_t num_settings,
+    void *userdata);
+static int s_decoder_on_settings_ack(void *userdata);
 
 static struct aws_http_connection_vtable s_h2_connection_vtable = {
     .channel_handler_vtable =
@@ -87,6 +92,8 @@ static struct aws_http_connection_vtable s_h2_connection_vtable = {
 static const struct aws_h2_decoder_vtable s_h2_decoder_vtable = {
     .on_data = NULL,
     .on_ping = s_decoder_on_ping,
+    .on_settings = s_decoder_on_settings,
+    .on_settings_ack = s_decoder_on_settings_ack,
 };
 
 static void s_lock_synced_data(struct aws_h2_connection *connection) {
@@ -209,6 +216,10 @@ static struct aws_h2_connection *s_connection_new(
         goto error;
     }
 
+    /* Initialize the value of settings */
+    memcpy(connection->thread_data.settings_peer, aws_h2_settings_initial, sizeof(aws_h2_settings_initial));
+    memcpy(connection->thread_data.settings_self, aws_h2_settings_initial, sizeof(aws_h2_settings_initial));
+
     /* Create a new decoder */
     struct aws_h2_decoder_params params = {
         .alloc = alloc,
@@ -527,13 +538,70 @@ static int s_decoder_on_ping(uint8_t opaque_data[AWS_H2_PING_DATA_SIZE], void *u
     }
 
     aws_h2_connection_enqueue_outgoing_frame(connection, ping_ack_frame);
-    s_try_write_outgoing_frames(connection);
     return AWS_OP_SUCCESS;
 error:
     CONNECTION_LOGF(ERROR, connection, "Ping ACK frame failed to be sent, error %s", aws_error_name(aws_last_error()));
     return AWS_OP_ERR;
 }
 
+static void s_aws_h2_decoder_change_settings(struct aws_h2_connection *connection) {
+    struct aws_h2_decoder *decoder = connection->thread_data.decoder;
+    uint32_t *settings_self = connection->thread_data.settings_self;
+    aws_h2_decoder_set_setting_header_table_size(decoder, settings_self[AWS_H2_SETTINGS_HEADER_TABLE_SIZE]);
+    aws_h2_decoder_set_setting_enable_push(decoder, settings_self[AWS_H2_SETTINGS_ENABLE_PUSH]);
+    aws_h2_decoder_set_setting_max_frame_size(decoder, settings_self[AWS_H2_SETTINGS_MAX_FRAME_SIZE]);
+}
+
+static int s_decoder_on_settings(
+    const struct aws_h2_frame_setting *settings_array,
+    size_t num_settings,
+    void *userdata) {
+    struct aws_h2_connection *connection = userdata;
+    /* Once all values have been processed, the recipient MUST immediately emit a SETTINGS frame with the ACK flag
+     * set.(RFC-7540 6.5.3) */
+    CONNECTION_LOG(TRACE, connection, "Setting frame processing ends");
+    struct aws_h2_frame *settings_ack_frame = aws_h2_frame_new_settings(connection->base.alloc, NULL, 0, true);
+    if (!settings_ack_frame) {
+        CONNECTION_LOGF(
+            ERROR, connection, "Settings ACK frame failed to be sent, error %s", aws_error_name(aws_last_error()));
+        goto error;
+    }
+    aws_h2_connection_enqueue_outgoing_frame(connection, settings_ack_frame);
+    /* Store the change to encoder and connection after enqueue the setting ACK frame */
+    struct aws_h2_frame_encoder *encoder = &connection->thread_data.encoder;
+    for (size_t i = 0; i < num_settings; i++) {
+        if (connection->thread_data.settings_peer[settings_array[i].id] == settings_array[i].value) {
+            /* No change, don't do any work */
+            continue;
+        }
+        switch (settings_array[i].id) {
+            case AWS_H2_SETTINGS_HEADER_TABLE_SIZE:
+                aws_h2_frame_encoder_set_setting_header_table_size(encoder, settings_array[i].value);
+                break;
+            case AWS_H2_SETTINGS_MAX_FRAME_SIZE:
+                aws_h2_frame_encoder_set_setting_max_frame_size(encoder, settings_array[i].value);
+                break;
+        }
+        connection->thread_data.settings_peer[settings_array[i].id] = settings_array[i].value;
+    }
+    return AWS_OP_SUCCESS;
+
+error:
+
+    return AWS_OP_ERR;
+}
+
+static int s_decoder_on_settings_ack(void *userdata) {
+    struct aws_h2_connection *connection = userdata;
+    /* #TODO track which SETTINGS frames is ACKed by this */
+
+    /* inform decoder about the settings */
+    s_aws_h2_decoder_change_settings(connection);
+    return AWS_OP_SUCCESS;
+}
+
+/* End decoder callbacks */
+
 static int s_send_connection_preface_client_string(struct aws_h2_connection *connection) {
 
     /* Just send the magic string on its own aws_io_message. */
@@ -563,7 +631,7 @@ static int s_send_connection_preface_client_string(struct aws_h2_connection *con
     return AWS_OP_ERR;
 }
 
-/* #TODO actually fill with settings */
+/* #TODO actually fill with initial settings */
 /* #TODO track which SETTINGS frames have been ACK'd */
 static int s_enqueue_settings_frame(struct aws_h2_connection *connection) {
     struct aws_allocator *alloc = connection->base.alloc;
@@ -650,7 +718,11 @@ static void s_stream_complete(struct aws_h2_connection *connection, struct aws_h
 static void s_activate_stream(struct aws_h2_connection *connection, struct aws_h2_stream *stream) {
     AWS_PRECONDITION(aws_channel_thread_is_callers_thread(connection->base.channel_slot->channel));
 
-    /* #TODO: don't exceed peer's max-concurrent-streams setting */
+    uint32_t max_concurrent_streams = connection->thread_data.settings_peer[AWS_H2_SETTINGS_MAX_CONCURRENT_STREAMS];
+    if (aws_hash_table_get_entry_count(&connection->thread_data.active_streams_map) >= max_concurrent_streams) {
+        AWS_H2_STREAM_LOG(ERROR, stream, "Failed activating stream, max concurrent streams are reached");
+        goto error;
+    }
 
     if (aws_hash_table_put(
             &connection->thread_data.active_streams_map, (void *)(size_t)stream->base.id, stream, NULL)) {
@@ -842,6 +914,8 @@ static int s_handler_process_read_message(
         aws_mem_release(message->allocator, message);
         message = NULL;
     }
+    /* Flush any outgoing frames that might have been queued as a result of decoder callbacks. */
+    s_try_write_outgoing_frames(connection);
     return AWS_OP_SUCCESS;
 shutdown:
     if (message) {

source/h2_decoder.c

@@ -244,6 +244,18 @@ struct aws_h2_decoder {
         bool malformed;
     } header_block_in_progress;
 
+    /* Settings for decoder, which is based on the settings sent to the peer and ACKed by peer */
+    struct {
+        /* the maximum size of the header compression table used to decode header blocks */
+        uint32_t header_table_size;
+        /* enable/disable server push */
+        uint32_t enable_push;
+        /*  the size of the largest frame payload */
+        uint32_t max_frame_size;
+    } settings;
+
+    struct aws_array_list settings_buffer_list;
+
     /* User callbacks and settings. */
     const struct aws_h2_decoder_vtable *vtable;
     void *userdata;
@@ -290,9 +302,19 @@ struct aws_h2_decoder *aws_h2_decoder_new(struct aws_h2_decoder_params *params)
         decoder->state = &s_state_prefix;
     }
 
+    decoder->settings.header_table_size = aws_h2_settings_initial[AWS_H2_SETTINGS_HEADER_TABLE_SIZE];
+    decoder->settings.enable_push = aws_h2_settings_initial[AWS_H2_SETTINGS_ENABLE_PUSH];
+    decoder->settings.max_frame_size = aws_h2_settings_initial[AWS_H2_SETTINGS_MAX_FRAME_SIZE];
+
+    if (aws_array_list_init_dynamic(
+            &decoder->settings_buffer_list, decoder->alloc, 0, sizeof(struct aws_h2_frame_setting))) {
+        goto array_list_failed;
+    }
+
     return decoder;
 
 failed_new_hpack:
+array_list_failed:
     aws_mem_release(params->alloc, allocation);
 failed_alloc:
     return NULL;
@@ -309,6 +331,7 @@ void aws_h2_decoder_destroy(struct aws_h2_decoder *decoder) {
     if (!decoder) {
         return;
     }
+    aws_array_list_clean_up(&decoder->settings_buffer_list);
     aws_hpack_context_destroy(decoder->hpack);
     s_reset_header_block_in_progress(decoder);
     aws_mem_release(decoder->alloc, decoder);
@@ -587,13 +610,13 @@ static int s_state_fn_prefix(struct aws_h2_decoder *decoder, struct aws_byte_cur
     }
 
     /* Validate payload length.  */
-    static const uint32_t MAX_FRAME_SIZE = 16384; /* #TODO handle the SETTINGS_MAX_FRAME_SIZE setting */
-    if (frame->payload_len > MAX_FRAME_SIZE) {
+    uint32_t max_frame_size = decoder->settings.max_frame_size;
+    if (frame->payload_len > max_frame_size) {
         DECODER_LOGF(
             ERROR,
             decoder,
             "Decoder's max frame size is %" PRIu32 ", but frame of size %" PRIu32 " was received.",
-            MAX_FRAME_SIZE,
+            max_frame_size,
             frame->payload_len);
         return aws_raise_error(AWS_ERROR_HTTP_INVALID_FRAME_SIZE);
     }
@@ -785,9 +808,6 @@ static int s_state_fn_frame_settings_begin(struct aws_h2_decoder *decoder, struc
         return aws_raise_error(AWS_ERROR_HTTP_INVALID_FRAME_SIZE);
     }
 
-    /* Report start of non-ACK settings frame */
-    DECODER_CALL_VTABLE(decoder, on_settings_begin);
-
     /* Enter looping states until all entries are consumed. */
     return s_decoder_switch_state(decoder, &s_state_frame_settings_loop);
 }
@@ -797,8 +817,12 @@ static int s_state_fn_frame_settings_loop(struct aws_h2_decoder *decoder, struct
     (void)input;
 
     if (decoder->frame_in_progress.payload_len == 0) {
-        /* Huzzah, done with the frame */
-        DECODER_CALL_VTABLE(decoder, on_settings_end);
+        /* Huzzah, done with the frame, fire the callback */
+        struct aws_array_list *buffer = &decoder->settings_buffer_list;
+        DECODER_CALL_VTABLE_ARGS(
+            decoder, on_settings, buffer->data, aws_array_list_length(&decoder->settings_buffer_list));
+        /* clean up the buffer */
+        aws_array_list_clear(&decoder->settings_buffer_list);
         return s_decoder_reset_state(decoder);
     }
 
@@ -831,7 +855,25 @@ static int s_state_fn_frame_settings_i(struct aws_h2_decoder *decoder, struct aw
     /* An endpoint that receives a SETTINGS frame with any unknown or unsupported identifier MUST ignore that setting.
      * RFC-7540 6.5.2 */
     if (id >= AWS_H2_SETTINGS_BEGIN_RANGE && id < AWS_H2_SETTINGS_END_RANGE) {
-        DECODER_CALL_VTABLE_ARGS(decoder, on_settings_i, id, value);
+        /* check the value meets the settings bounds */
+        if (value < aws_h2_settings_bounds[id][0] || value > aws_h2_settings_bounds[id][1]) {
+            DECODER_LOGF(
+                ERROR, decoder, "A value of SETTING frame is invalid, id: %" PRIu16 ", value: %" PRIu32, id, value);
+            if (id == AWS_H2_SETTINGS_INITIAL_WINDOW_SIZE) {
+                return aws_raise_error(AWS_H2_ERR_FLOW_CONTROL_ERROR);
+            } else {
+                /* TODO: translates errors from AWS_ERROR_HTTP_XYZ into AWS_H2_ERR_XYZ */
+                return aws_raise_error(AWS_ERROR_HTTP_PROTOCOL_ERROR);
+            }
+        }
+        struct aws_h2_frame_setting setting;
+        setting.id = id;
+        setting.value = value;
+        /* array_list will keep a copy of setting, it is fine to be a local variable */
+        if (aws_array_list_push_back(&decoder->settings_buffer_list, &setting)) {
+            DECODER_LOGF(ERROR, decoder, "Writing setting to buffer failed, %s", aws_error_name(aws_last_error()));
+            return AWS_OP_ERR;
+        }
     }
 
     /* Update payload len */
@@ -848,6 +890,12 @@ static int s_state_fn_frame_settings_i(struct aws_h2_decoder *decoder, struct aw
  */
 static int s_state_fn_frame_push_promise(struct aws_h2_decoder *decoder, struct aws_byte_cursor *input) {
 
+    if (decoder->settings.enable_push == 0) {
+        /* treat the receipt of a PUSH_PROMISE frame as a connection error of type PROTOCOL_ERROR.(RFC-7540 6.5.2) */
+        DECODER_LOG(ERROR, decoder, "PUSH_PROMISE is invalid, the seting for enable push is 0");
+        return aws_raise_error(AWS_ERROR_HTTP_PROTOCOL_ERROR);
+    }
+
     AWS_ASSERT(input->len >= s_state_frame_push_promise_requires_4_bytes);
 
     uint32_t promised_stream_id = 0;
@@ -1342,3 +1390,15 @@ static int s_state_fn_connection_preface_string(struct aws_h2_decoder *decoder,
     /* Remain in state until more data arrives */
     return AWS_OP_SUCCESS;
 }
+
+void aws_h2_decoder_set_setting_header_table_size(struct aws_h2_decoder *decoder, uint32_t data) {
+    decoder->settings.header_table_size = data;
+}
+
+void aws_h2_decoder_set_setting_enable_push(struct aws_h2_decoder *decoder, uint32_t data) {
+    decoder->settings.enable_push = data;
+}
+
+void aws_h2_decoder_set_setting_max_frame_size(struct aws_h2_decoder *decoder, uint32_t data) {
+    decoder->settings.max_frame_size = data;
+}

source/h2_frames.c

@@ -136,9 +136,7 @@ static int s_get_max_contiguous_payload_length(
         return aws_raise_error(AWS_ERROR_SHORT_BUFFER);
     }
 
-    /* #TODO actually check against encoder's current MAX_FRAME_SIZE */
-    (void)encoder;
-    const size_t max_payload_given_settings = AWS_H2_PAYLOAD_MAX;
+    size_t max_payload_given_settings = encoder->settings.max_frame_size;
 
     *max_payload_length = aws_min_size(max_payload_given_space_available, max_payload_given_settings);
     return AWS_OP_SUCCESS;
@@ -248,6 +246,9 @@ int aws_h2_frame_encoder_init(
         return AWS_OP_ERR;
     }
 
+    encoder->settings.header_table_size = aws_h2_settings_initial[AWS_H2_SETTINGS_HEADER_TABLE_SIZE];
+    encoder->settings.max_frame_size = aws_h2_settings_initial[AWS_H2_SETTINGS_MAX_FRAME_SIZE];
+
     return AWS_OP_SUCCESS;
 }
 void aws_h2_frame_encoder_clean_up(struct aws_h2_frame_encoder *encoder) {
@@ -1138,3 +1139,12 @@ int aws_h2_encode_frame(
     encoder->current_frame = *frame_complete ? NULL : frame;
     return AWS_OP_SUCCESS;
 }
+
+void aws_h2_frame_encoder_set_setting_header_table_size(struct aws_h2_frame_encoder *encoder, uint32_t data) {
+    /* TODO:: pass down to the HPACK context aws_hpack_resize_dynamic_table() */
+    encoder->settings.header_table_size = data;
+}
+
+void aws_h2_frame_encoder_set_setting_max_frame_size(struct aws_h2_frame_encoder *encoder, uint32_t data) {
+    encoder->settings.max_frame_size = data;
+}