/* * * Copyright (c) 2016 MariaDB Corporation Ab * * Use of this software is governed by the Business Source License included * in the LICENSE.TXT file and at www.mariadb.com/bsl11. * * Change Date: 2019-07-01 * * On the date above, in accordance with the Business Source License, use * of this software will be governed by version 2 or later of the General * Public License. */ /** * @file mysql_client.c * * MySQL Protocol module for handling the protocol between the gateway * and the client. * * Revision History * Date Who Description * 14/06/2013 Mark Riddoch Initial version * 17/06/2013 Massimiliano Pinto Added Client To MaxScale routines * 24/06/2013 Massimiliano Pinto Added: fetch passwords from service users' hashtable * 02/09/2013 Massimiliano Pinto Added: session refcount * 16/12/2013 Massimiliano Pinto Added: client closed socket detection with recv(..., MSG_PEEK) * 24/02/2014 Massimiliano Pinto Added: on failed authentication a new users' table is loaded * with time and frequency limitations * If current user is authenticated the new users' table will * replace the old one * 28/02/2014 Massimiliano Pinto Added: client IPv4 in dcb->ipv4 and inet_ntop for string * representation * 11/03/2014 Massimiliano Pinto Added: Unix socket support * 07/05/2014 Massimiliano Pinto Added: specific version string in server handshake * 09/09/2014 Massimiliano Pinto Added: 777 permission for socket path * 13/10/2014 Massimiliano Pinto Added: dbname authentication check * 10/11/2014 Massimiliano Pinto Added: client charset added to protocol struct * 29/05/2015 Markus Makela Added SSL support * 11/06/2015 Martin Brampton COM_QUIT suppressed for persistent connections * 04/09/2015 Martin Brampton Introduce DUMMY session to fulfill guarantee DCB always has session * 09/09/2015 Martin Brampton Modify error handler calls * 11/01/2016 Martin Brampton Remove SSL write code, now handled at lower level; * replace gwbuf_consume by gwbuf_free (multiple). * 07/02/2016 Martin Brampton Split off authentication and SSL. * 31/05/2016 Martin Brampton Implement connection throttling */ #define MXS_MODULE_NAME "MySQLClient" #include #include #include #include #include #include #include #include #include #include #include #include #include static int process_init(void); static void process_finish(void); static int thread_init(void); static void thread_finish(void); static int gw_MySQLAccept(DCB *listener); static int gw_MySQLListener(DCB *listener, char *config_bind); static int gw_read_client_event(DCB* dcb); static int gw_write_client_event(DCB *dcb); static int gw_MySQLWrite_client(DCB *dcb, GWBUF *queue); static int gw_error_client_event(DCB *dcb); static int gw_client_close(DCB *dcb); static int gw_client_hangup_event(DCB *dcb); static char *gw_default_auth(); static int gw_connection_limit(DCB *dcb, int limit); static int MySQLSendHandshake(DCB* dcb); static int route_by_statement(MXS_SESSION *, uint64_t, GWBUF **); static void mysql_client_auth_error_handling(DCB *dcb, int auth_val, int packet_number); static int gw_read_do_authentication(DCB *dcb, GWBUF *read_buffer, int nbytes_read); static int gw_read_normal_data(DCB *dcb, GWBUF *read_buffer, int nbytes_read); static int gw_read_finish_processing(DCB *dcb, GWBUF *read_buffer, uint64_t capabilities); static bool ensure_complete_packet(DCB *dcb, GWBUF **read_buffer, int nbytes_read); static void gw_process_one_new_client(DCB *client_dcb); /* * The "module object" for the mysqld client protocol module. */ /** * The module entry point routine. It is this routine that * must populate the structure that is referred to as the * "module object", this is a structure with the set of * external entry points for this module. * * @return The module object */ MXS_MODULE* MXS_CREATE_MODULE() { static MXS_PROTOCOL MyObject = { gw_read_client_event, /* Read - EPOLLIN handler */ gw_MySQLWrite_client, /* Write - data from gateway */ gw_write_client_event, /* WriteReady - EPOLLOUT handler */ gw_error_client_event, /* Error - EPOLLERR handler */ gw_client_hangup_event, /* HangUp - EPOLLHUP handler */ gw_MySQLAccept, /* Accept */ NULL, /* Connect */ gw_client_close, /* Close */ gw_MySQLListener, /* Listen */ NULL, /* Authentication */ NULL, /* Session */ gw_default_auth, /* Default authenticator */ gw_connection_limit, /* Send error connection limit */ NULL }; static MXS_MODULE info = { MXS_MODULE_API_PROTOCOL, MXS_MODULE_GA, MXS_PROTOCOL_VERSION, "The client to MaxScale MySQL protocol implementation", "V1.1.0", &MyObject, process_init, process_finish, thread_init, thread_finish, { {MXS_END_MODULE_PARAMS} } }; return &info; } /*lint +e14 */ /** * Performs process wide initialization. * * @return 0 if successful, non-zero otherwise. */ static int process_init(void) { int rv = mysql_library_init(0, NULL, NULL); if (rv != 0) { MXS_ERROR("MySQL initialization failed, MariaDB MaxScale will exit. " "MySQL Error: %d, %s.", mysql_errno(NULL), mysql_error(NULL)); } return rv; } /** * Performs process wide finalization. */ static void process_finish(void) { mysql_library_end(); } /** * Performs thread-specific initialization. * * @return 0 if successful, non-zero otherwise. */ static int thread_init(void) { int rv = mysql_thread_init(); if (rv != 0) { MXS_ERROR("MySQL thread initialization failed, the thread will exit."); } return rv; } /** * Performs thread specific finalization. */ static void thread_finish(void) { mysql_thread_end(); } /** * The default authenticator name for this protocol * * @return name of authenticator */ static char *gw_default_auth() { return "MySQLAuth"; } /** * MySQLSendHandshake * * @param dcb The descriptor control block to use for sending the handshake request * @return The packet length sent */ int MySQLSendHandshake(DCB* dcb) { uint8_t *outbuf = NULL; uint32_t mysql_payload_size = 0; uint8_t mysql_packet_header[4]; uint8_t mysql_packet_id = 0; /* uint8_t mysql_filler = GW_MYSQL_HANDSHAKE_FILLER; not needed*/ uint8_t mysql_protocol_version = GW_MYSQL_PROTOCOL_VERSION; uint8_t *mysql_handshake_payload = NULL; uint8_t mysql_thread_id_num[4]; uint8_t mysql_scramble_buf[9] = ""; uint8_t mysql_plugin_data[13] = ""; uint8_t mysql_server_capabilities_one[2]; uint8_t mysql_server_capabilities_two[2]; uint8_t mysql_server_language = 8; uint8_t mysql_server_status[2]; uint8_t mysql_scramble_len = 21; uint8_t mysql_filler_ten[10] = {}; /* uint8_t mysql_last_byte = 0x00; not needed */ char server_scramble[GW_MYSQL_SCRAMBLE_SIZE + 1] = ""; char *version_string; int len_version_string = 0; int id_num; bool is_maria = false; if (dcb->service->dbref) { mysql_server_language = dcb->service->dbref->server->charset; if (dcb->service->dbref->server->server_string && strstr(dcb->service->dbref->server->server_string, "10.2.")) { /** The backend servers support the extended capabilities */ is_maria = true; } } MySQLProtocol *protocol = DCB_PROTOCOL(dcb, MySQLProtocol); GWBUF *buf; /* get the version string from service property if available*/ if (dcb->service->version_string != NULL) { version_string = dcb->service->version_string; len_version_string = strlen(version_string); } else { version_string = GW_MYSQL_VERSION; len_version_string = strlen(GW_MYSQL_VERSION); } gw_generate_random_str(server_scramble, GW_MYSQL_SCRAMBLE_SIZE); // copy back to the caller memcpy(protocol->scramble, server_scramble, GW_MYSQL_SCRAMBLE_SIZE); if (is_maria) { /** * The new 10.2 capability flags are stored in the last 4 bytes of the * 10 byte filler block. */ uint32_t new_flags = MXS_MARIA_CAP_STMT_BULK_OPERATIONS; memcpy(mysql_filler_ten + 6, &new_flags, sizeof(new_flags)); } // thread id, now put thePID id_num = getpid() + dcb->fd; gw_mysql_set_byte4(mysql_thread_id_num, id_num); memcpy(mysql_scramble_buf, server_scramble, 8); memcpy(mysql_plugin_data, server_scramble + 8, 12); /** * Use the default authentication plugin name in the initial handshake. If the * authenticator needs to change the authentication method, it should send * an AuthSwitchRequest packet to the client. */ const char* plugin_name = DEFAULT_MYSQL_AUTH_PLUGIN; int plugin_name_len = strlen(plugin_name); mysql_payload_size = sizeof(mysql_protocol_version) + (len_version_string + 1) + sizeof(mysql_thread_id_num) + 8 + sizeof(/* mysql_filler */ uint8_t) + sizeof(mysql_server_capabilities_one) + sizeof(mysql_server_language) + sizeof(mysql_server_status) + sizeof(mysql_server_capabilities_two) + sizeof(mysql_scramble_len) + sizeof(mysql_filler_ten) + 12 + sizeof(/* mysql_last_byte */ uint8_t) + plugin_name_len + sizeof(/* mysql_last_byte */ uint8_t); // allocate memory for packet header + payload if ((buf = gwbuf_alloc(sizeof(mysql_packet_header) + mysql_payload_size)) == NULL) { ss_dassert(buf != NULL); return 0; } outbuf = GWBUF_DATA(buf); // write packet header with mysql_payload_size gw_mysql_set_byte3(mysql_packet_header, mysql_payload_size); // write packet number, now is 0 mysql_packet_header[3] = mysql_packet_id; memcpy(outbuf, mysql_packet_header, sizeof(mysql_packet_header)); // current buffer pointer mysql_handshake_payload = outbuf + sizeof(mysql_packet_header); // write protocol version memcpy(mysql_handshake_payload, &mysql_protocol_version, sizeof(mysql_protocol_version)); mysql_handshake_payload = mysql_handshake_payload + sizeof(mysql_protocol_version); // write server version plus 0 filler strcpy((char *)mysql_handshake_payload, version_string); mysql_handshake_payload = mysql_handshake_payload + len_version_string; *mysql_handshake_payload = 0x00; mysql_handshake_payload++; // write thread id memcpy(mysql_handshake_payload, mysql_thread_id_num, sizeof(mysql_thread_id_num)); mysql_handshake_payload = mysql_handshake_payload + sizeof(mysql_thread_id_num); // write scramble buf memcpy(mysql_handshake_payload, mysql_scramble_buf, 8); mysql_handshake_payload = mysql_handshake_payload + 8; *mysql_handshake_payload = GW_MYSQL_HANDSHAKE_FILLER; mysql_handshake_payload++; // write server capabilities part one mysql_server_capabilities_one[0] = (uint8_t)GW_MYSQL_CAPABILITIES_SERVER; mysql_server_capabilities_one[1] = (uint8_t)(GW_MYSQL_CAPABILITIES_SERVER >> 8); // Check that we match the old values ss_dassert(mysql_server_capabilities_one[0] = 0xff); ss_dassert(mysql_server_capabilities_one[1] = 0xf7); if (is_maria) { /** A MariaDB 10.2 server doesn't send the CLIENT_MYSQL capability * to signal that it supports extended capabilities */ mysql_server_capabilities_one[0] &= ~(uint8_t)GW_MYSQL_CAPABILITIES_CLIENT_MYSQL; } if (ssl_required_by_dcb(dcb)) { mysql_server_capabilities_one[1] |= (int)GW_MYSQL_CAPABILITIES_SSL >> 8; } memcpy(mysql_handshake_payload, mysql_server_capabilities_one, sizeof(mysql_server_capabilities_one)); mysql_handshake_payload = mysql_handshake_payload + sizeof(mysql_server_capabilities_one); // write server language memcpy(mysql_handshake_payload, &mysql_server_language, sizeof(mysql_server_language)); mysql_handshake_payload = mysql_handshake_payload + sizeof(mysql_server_language); //write server status mysql_server_status[0] = 2; mysql_server_status[1] = 0; memcpy(mysql_handshake_payload, mysql_server_status, sizeof(mysql_server_status)); mysql_handshake_payload = mysql_handshake_payload + sizeof(mysql_server_status); //write server capabilities part two mysql_server_capabilities_two[0] = (uint8_t)(GW_MYSQL_CAPABILITIES_SERVER >> 16); mysql_server_capabilities_two[1] = (uint8_t)(GW_MYSQL_CAPABILITIES_SERVER >> 24); // Check that we match the old values ss_dassert(mysql_server_capabilities_two[0] == 15); /** NOTE: pre-2.1 versions sent the fourth byte of the capabilities as the value 128 even though there's no such capability. */ memcpy(mysql_handshake_payload, mysql_server_capabilities_two, sizeof(mysql_server_capabilities_two)); mysql_handshake_payload = mysql_handshake_payload + sizeof(mysql_server_capabilities_two); // write scramble_len memcpy(mysql_handshake_payload, &mysql_scramble_len, sizeof(mysql_scramble_len)); mysql_handshake_payload = mysql_handshake_payload + sizeof(mysql_scramble_len); //write 10 filler memcpy(mysql_handshake_payload, mysql_filler_ten, sizeof(mysql_filler_ten)); mysql_handshake_payload = mysql_handshake_payload + sizeof(mysql_filler_ten); // write plugin data memcpy(mysql_handshake_payload, mysql_plugin_data, 12); mysql_handshake_payload = mysql_handshake_payload + 12; //write last byte, 0 *mysql_handshake_payload = 0x00; mysql_handshake_payload++; // to be understanded ???? memcpy(mysql_handshake_payload, plugin_name, plugin_name_len); mysql_handshake_payload = mysql_handshake_payload + plugin_name_len; //write last byte, 0 *mysql_handshake_payload = 0x00; // writing data in the Client buffer queue dcb->func.write(dcb, buf); return sizeof(mysql_packet_header) + mysql_payload_size; } /** * Write function for client DCB: writes data from MaxScale to Client * * @param dcb The DCB of the client * @param queue Queue of buffers to write */ int gw_MySQLWrite_client(DCB *dcb, GWBUF *queue) { return dcb_write(dcb, queue); } /** * @brief Client read event triggered by EPOLLIN * * @param dcb Descriptor control block * @return 0 if succeed, 1 otherwise */ int gw_read_client_event(DCB* dcb) { MySQLProtocol *protocol; GWBUF *read_buffer = NULL; int return_code = 0; int nbytes_read = 0; int max_bytes = 0; CHK_DCB(dcb); if (dcb->dcb_role != DCB_ROLE_CLIENT_HANDLER) { MXS_ERROR("DCB must be a client handler for MySQL client protocol."); return 1; } protocol = (MySQLProtocol *)dcb->protocol; CHK_PROTOCOL(protocol); #ifdef SS_DEBUG MXS_DEBUG("[gw_read_client_event] Protocol state: %s", gw_mysql_protocol_state2string(protocol->protocol_auth_state)); #endif /** * The use of max_bytes seems like a hack, but no better option is available * at the time of writing. When a MySQL server receives a new connection * request, it sends an Initial Handshake Packet. Where the client wants to * use SSL, it responds with an SSL Request Packet (in place of a Handshake * Response Packet). The SSL Request Packet contains only the basic header, * and not the user credentials. It is 36 bytes long. The server then * initiates the SSL handshake (via calls to OpenSSL). * * In many cases, this is what happens. But occasionally, the client seems * to send a packet much larger than 36 bytes (in tests it was 333 bytes). * If the whole of the packet is read, it is then lost to the SSL handshake * process. Why this happens is presently unknown. Reading just 36 bytes * when the server requires SSL and SSL has not yet been negotiated seems * to solve the problem. * * If a neater solution can be found, so much the better. */ if (ssl_required_but_not_negotiated(dcb)) { max_bytes = 36; } return_code = dcb_read(dcb, &read_buffer, max_bytes); if (return_code < 0) { dcb_close(dcb); } if (0 == (nbytes_read = gwbuf_length(read_buffer))) { return return_code; } return_code = 0; switch (protocol->protocol_auth_state) { /** * * When a listener receives a new connection request, it creates a * request handler DCB to for the client connection. The listener also * sends the initial authentication request to the client. The first * time this function is called from the poll loop, the client reply * to the authentication request should be available. * * If the authentication is successful the protocol authentication state * will be changed to MYSQL_IDLE (see below). * */ case MXS_AUTH_STATE_MESSAGE_READ: if (nbytes_read < 3 || (0 == max_bytes && nbytes_read < MYSQL_GET_PACKET_LEN(read_buffer)) || (0 != max_bytes && nbytes_read < max_bytes)) { dcb->dcb_readqueue = gwbuf_append(dcb->dcb_readqueue, read_buffer); } else { if (nbytes_read > MYSQL_GET_PACKET_LEN(read_buffer)) { // We read more data than was needed dcb->dcb_readqueue = gwbuf_append(dcb->dcb_readqueue, read_buffer); read_buffer = modutil_get_next_MySQL_packet(&dcb->dcb_readqueue); } return_code = gw_read_do_authentication(dcb, read_buffer, nbytes_read); } break; /** * * Once a client connection is authenticated, the protocol authentication * state will be MYSQL_IDLE and so every event of data received will * result in a call that comes to this section of code. * */ case MXS_AUTH_STATE_COMPLETE: /* After this call read_buffer will point to freed data */ return_code = gw_read_normal_data(dcb, read_buffer, nbytes_read); break; case MXS_AUTH_STATE_FAILED: gwbuf_free(read_buffer); return_code = 1; break; default: MXS_ERROR("In mysql_client.c unexpected protocol authentication state"); break; } return return_code; } /** * @brief Store client connection information into the DCB * @param dcb Client DCB * @param buffer Buffer containing the handshake response packet */ static void store_client_information(DCB *dcb, GWBUF *buffer) { size_t len = gwbuf_length(buffer); uint8_t data[len]; MySQLProtocol *proto = (MySQLProtocol*)dcb->protocol; MYSQL_session *ses = (MYSQL_session*)dcb->data; gwbuf_copy_data(buffer, 0, len, data); ss_dassert(MYSQL_GET_PAYLOAD_LEN(data) + MYSQL_HEADER_LEN == len || len == MYSQL_AUTH_PACKET_BASE_SIZE); // For SSL request packet proto->client_capabilities = gw_mysql_get_byte4(data + MYSQL_CLIENT_CAP_OFFSET); proto->charset = data[MYSQL_CHARSET_OFFSET]; /** MariaDB 10.2 compatible clients don't set the first bit to signal that * there are extra capabilities stored in the last 4 bytes of the 23 byte filler. */ if ((proto->client_capabilities & GW_MYSQL_CAPABILITIES_CLIENT_MYSQL) == 0) { proto->extra_capabilities = gw_mysql_get_byte4(data + MARIADB_CAP_OFFSET); } if (len > MYSQL_AUTH_PACKET_BASE_SIZE) { strcpy(ses->user, (char*)data + MYSQL_AUTH_PACKET_BASE_SIZE); if (proto->client_capabilities & GW_MYSQL_CAPABILITIES_CONNECT_WITH_DB) { /** Client supports default database on connect */ size_t userlen = strlen(ses->user) + 1; /** Skip the authentication token, it is handled by the authenticators */ uint8_t authlen = data[MYSQL_AUTH_PACKET_BASE_SIZE + userlen]; size_t dboffset = MYSQL_AUTH_PACKET_BASE_SIZE + userlen + authlen + 1; if (data[dboffset]) { /** Client is connecting with a default database */ strcpy(ses->db, (char*)data + dboffset); } } } } /** * @brief Debug check function for authentication packets * * Check that the packet is consistent with how the protocol works and that no * unexpected data is processed. * * @param dcb Client DCB * @param buf Buffer containing packet * @param bytes Number of bytes available */ static void check_packet(DCB *dcb, GWBUF *buf, int bytes) { uint8_t hdr[MYSQL_HEADER_LEN]; ss_dassert(gwbuf_copy_data(buf, 0, MYSQL_HEADER_LEN, hdr) == MYSQL_HEADER_LEN); int buflen = gwbuf_length(buf); int pktlen = MYSQL_GET_PAYLOAD_LEN(hdr) + MYSQL_HEADER_LEN; if (bytes == MYSQL_AUTH_PACKET_BASE_SIZE) { /** This is an SSL request packet */ ss_dassert(dcb->listener->ssl); ss_dassert(buflen == bytes && pktlen >= buflen); } else { /** Normal packet */ ss_dassert(buflen == pktlen); } } /** * @brief Client read event, process when client not yet authenticated * * @param dcb Descriptor control block * @param read_buffer A buffer containing the data read from client * @param nbytes_read The number of bytes of data read * @return 0 if succeed, 1 otherwise */ static int gw_read_do_authentication(DCB *dcb, GWBUF *read_buffer, int nbytes_read) { ss_debug(check_packet(dcb, read_buffer, nbytes_read)); /** Allocate the shared session structure */ if (dcb->data == NULL && (dcb->data = mysql_session_alloc()) == NULL) { dcb_close(dcb); return 1; } /** Read the client's packet sequence and increment that by one */ uint8_t next_sequence; gwbuf_copy_data(read_buffer, MYSQL_SEQ_OFFSET, 1, &next_sequence); if (next_sequence == 1 || (ssl_required_by_dcb(dcb) && next_sequence == 2)) { /** This is the first response from the client, read the connection * information and store them in the shared structure. For SSL connections, * this will be packet number two since the first packet will be the * Protocol::SSLRequest packet. * * @see https://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::SSLRequest */ store_client_information(dcb, read_buffer); } next_sequence++; /** * The first step in the authentication process is to extract the * relevant information from the buffer supplied and place it * into a data structure pointed to by the DCB. The "success" * result is not final, it implies only that the process is so * far successful, not that authentication has completed. If the * data extraction succeeds, then a call is made to the actual * authenticate function to carry out the user checks. */ int auth_val = dcb->authfunc.extract(dcb, read_buffer); if (MXS_AUTH_SUCCEEDED == auth_val) { auth_val = dcb->authfunc.authenticate(dcb); } MySQLProtocol *protocol = (MySQLProtocol *)dcb->protocol; /** * At this point, if the auth_val return code indicates success * the user authentication has been successfully completed. * But in order to have a working connection, a session has to * be created. Provided that is also successful (indicated by a * non-null session) then the whole process has succeeded. In all * other cases an error return is made. */ if (MXS_AUTH_SUCCEEDED == auth_val) { if (dcb->user == NULL) { /** User authentication complete, copy the username to the DCB */ MYSQL_session *ses = dcb->data; if ((dcb->user = MXS_STRDUP(ses->user)) == NULL) { dcb_close(dcb); gwbuf_free(read_buffer); return 0; } } protocol->protocol_auth_state = MXS_AUTH_STATE_RESPONSE_SENT; /** * Create session, and a router session for it. * If successful, there will be backend connection(s) * after this point. The protocol authentication state * is changed so that future data will go through the * normal data handling function instead of this one. */ MXS_SESSION *session = session_alloc(dcb->service, dcb); if (session != NULL) { CHK_SESSION(session); ss_dassert(session->state != SESSION_STATE_ALLOC && session->state != SESSION_STATE_DUMMY); protocol->protocol_auth_state = MXS_AUTH_STATE_COMPLETE; mxs_mysql_send_ok(dcb, next_sequence, 0, NULL); } else { auth_val = MXS_AUTH_NO_SESSION; } } /** * If we did not get success throughout or authentication is not yet complete, * then the protocol state is updated, the client is notified of the failure * and the DCB is closed. */ if (MXS_AUTH_SUCCEEDED != auth_val && MXS_AUTH_INCOMPLETE != auth_val && MXS_AUTH_SSL_INCOMPLETE != auth_val) { protocol->protocol_auth_state = MXS_AUTH_STATE_FAILED; mysql_client_auth_error_handling(dcb, auth_val, next_sequence); /** * Close DCB and which will release MYSQL_session */ dcb_close(dcb); } /* One way or another, the buffer is now fully processed */ gwbuf_free(read_buffer); return 0; } /** * Helper function to split and store the buffer * @param client_dcb Client DCB * @param queue Buffer to split * @param offset Offset where the split is made * @return The first part of the buffer */ static GWBUF* split_and_store(DCB *client_dcb, GWBUF* queue, int offset) { GWBUF* newbuf = gwbuf_split(&queue, offset); dcb_append_readqueue(client_dcb, queue); return newbuf; } /** * @brief Check if the DCB is idle from the protocol's point of view * * This checks if all expected data from the DCB has been read. The values * prefixed with @c protocol_ should be manipulated by the protocol modules. * * @param dcb DCB to check * @return True if the DCB protocol is not expecting any data */ static bool protocol_is_idle(DCB *dcb) { return dcb->protocol_bytes_processed == dcb->protocol_packet_length; } /** * @brief Process the commands the client is executing * * The data read from the network is not guaranteed to contain a complete MySQL * packet. This means that it is possible that a command sent by the client is * split across multiple network packets and those packets need to be processed * individually. * * The forwarding of the data to the routers starts once the length and command * bytes have been read. The @c current_command field of the protocol * structure is guaranteed to always represent the current command being executed * by the client. * * Currently the gathered information is used by the readconnroute module to * detect COM_CHANGE_USER packets. * * @param dcb Client MySQL protocol struct * @param bytes_available Number of bytes available * @param queue Data written by the client * @return True if routing can proceed, false if processing should be attempted * later when more data is available */ static bool process_client_commands(DCB* dcb, int bytes_available, GWBUF** buffer) { GWBUF* queue = *buffer; /** Make sure we have enough data if the client is sending a new command */ if (protocol_is_idle(dcb) && bytes_available < MYSQL_HEADER_LEN) { dcb_append_readqueue(dcb, queue); return false; } int offset = 0; while (bytes_available) { if (protocol_is_idle(dcb)) { int pktlen; uint8_t cmd = (uint8_t)MYSQL_COM_QUERY; // Treat empty packets as COM_QUERY uint8_t packet_header[MYSQL_HEADER_LEN]; if (gwbuf_copy_data(queue, offset, MYSQL_HEADER_LEN, packet_header) != MYSQL_HEADER_LEN) { ss_dassert(offset > 0); queue = split_and_store(dcb, queue, offset); break; } pktlen = gw_mysql_get_byte3(packet_header); /** * Check if the packet is empty, and if not, if we have the command byte. * If we an empty packet or have at least 5 bytes of data, we can start * sending the data to the router. */ if (pktlen && gwbuf_copy_data(queue, offset + MYSQL_HEADER_LEN, 1, &cmd) != 1) { if ((queue = split_and_store(dcb, queue, offset)) == NULL) { ss_dassert(bytes_available - offset == MYSQL_HEADER_LEN); return false; } ss_dassert(offset > 0); break; } MySQLProtocol *proto = (MySQLProtocol*)dcb->protocol; if (dcb->protocol_packet_length - MYSQL_HEADER_LEN != GW_MYSQL_MAX_PACKET_LEN) { /** We're processing the first packet of a command */ proto->current_command = cmd; } dcb->protocol_packet_length = pktlen + MYSQL_HEADER_LEN; dcb->protocol_bytes_processed = 0; } int bytes_needed = dcb->protocol_packet_length - dcb->protocol_bytes_processed; int packet_bytes = bytes_needed <= bytes_available ? bytes_needed : bytes_available; bytes_available -= packet_bytes; dcb->protocol_bytes_processed += packet_bytes; offset += packet_bytes; ss_dassert(dcb->protocol_bytes_processed <= dcb->protocol_packet_length); } ss_dassert(bytes_available >= 0); ss_dassert(queue); *buffer = queue; return true; } /** * @brief Client read event, process data, client already authenticated * * First do some checks and get the router capabilities. If the router * wants to process each individual statement, then the data must be split * into individual SQL statements. Any data that is left over is held in the * DCB read queue. * * Finally, the general client data processing function is called. * * @param dcb Descriptor control block * @param read_buffer A buffer containing the data read from client * @param nbytes_read The number of bytes of data read * @return 0 if succeed, 1 otherwise */ static int gw_read_normal_data(DCB *dcb, GWBUF *read_buffer, int nbytes_read) { MXS_SESSION *session; mxs_session_state_t session_state_value; uint64_t capabilities = 0; session = dcb->session; CHK_SESSION(session); session_state_value = session->state; if (session_state_value != SESSION_STATE_ROUTER_READY) { if (session_state_value != SESSION_STATE_STOPPING) { MXS_ERROR("Session received a query in incorrect state %s", STRSESSIONSTATE(session_state_value)); } gwbuf_free(read_buffer); dcb_close(dcb); return 1; } /** Ask what type of input the router/filter chain expects */ capabilities = service_get_capabilities(session->service); /** If the router requires statement input we need to make sure that * a complete SQL packet is read before continuing. The current command * that is tracked by the protocol module is updated in route_by_statement() */ if (rcap_type_required(capabilities, RCAP_TYPE_STMT_INPUT)) { uint8_t pktlen[MYSQL_HEADER_LEN]; size_t n_copied = gwbuf_copy_data(read_buffer, 0, MYSQL_HEADER_LEN, pktlen); if (n_copied != sizeof(pktlen) || nbytes_read < MYSQL_GET_PAYLOAD_LEN(pktlen) + MYSQL_HEADER_LEN) { dcb->dcb_readqueue = gwbuf_append(dcb->dcb_readqueue, read_buffer); return 0; } gwbuf_set_type(read_buffer, GWBUF_TYPE_MYSQL); } /** Update the current protocol command being executed */ else if (!process_client_commands(dcb, nbytes_read, &read_buffer)) { return 0; } /** * Handle COM_SET_OPTION. This seems to be only used by some versions of PHP. * * The option is stored as a two byte integer with the values 0 for enabling * multi-statements and 1 for disabling it. */ MySQLProtocol *proto = dcb->protocol; uint8_t opt; if (proto->current_command == MYSQL_COM_SET_OPTION && gwbuf_copy_data(read_buffer, MYSQL_HEADER_LEN + 2, 1, &opt)) { if (opt) { proto->client_capabilities &= ~GW_MYSQL_CAPABILITIES_MULTI_STATEMENTS; } else { proto->client_capabilities |= GW_MYSQL_CAPABILITIES_MULTI_STATEMENTS; } } return gw_read_finish_processing(dcb, read_buffer, capabilities); } /** * Check if a connection qualifies to be added into the persistent connection pool * * @param dcb The client DCB to check */ void check_pool_candidate(DCB* dcb) { MXS_SESSION *session = dcb->session; MySQLProtocol *proto = (MySQLProtocol*)dcb->protocol; if (proto->current_command == MYSQL_COM_QUIT) { /** The client is closing the connection. We know that this will be the * last command the client sends so the backend connections are very likely * to be in an idle state. * * If the client is pipelining the queries (i.e. sending N request as * a batch and then expecting N responses) then it is possible that * the backend connections are not idle when the COM_QUIT is received. * In most cases we can assume that the connections are idle. */ session_qualify_for_pool(session); } } /** * @brief Client read event, common processing after single statement handling * * @param dcb Descriptor control block * @param read_buffer A buffer containing the data read from client * @param capabilities The router capabilities flags * @return 0 if succeed, 1 otherwise */ static int gw_read_finish_processing(DCB *dcb, GWBUF *read_buffer, uint64_t capabilities) { MXS_SESSION *session = dcb->session; uint8_t *payload = GWBUF_DATA(read_buffer); MySQLProtocol *proto = (MySQLProtocol*)dcb->protocol; CHK_PROTOCOL(proto); int return_code = 0; /** Reset error handler when routing of the new query begins */ dcb->dcb_errhandle_called = false; if (rcap_type_required(capabilities, RCAP_TYPE_STMT_INPUT)) { /** * Feed each statement completely and separately to router. */ return_code = route_by_statement(session, capabilities, &read_buffer) ? 0 : 1; if (read_buffer != NULL) { /* Must have been data left over */ /* Add incomplete mysql packet to read queue */ dcb->dcb_readqueue = gwbuf_append(dcb->dcb_readqueue, read_buffer); } } else if (NULL != session->router_session || (rcap_type_required(capabilities, RCAP_TYPE_NO_RSESSION))) { /** Check if this connection qualifies for the connection pool */ check_pool_candidate(dcb); /** Feed the whole buffer to the router */ return_code = MXS_SESSION_ROUTE_QUERY(session, read_buffer) ? 0 : 1; } /* else return_code is still 0 from when it was originally set */ /* Note that read_buffer has been freed or transferred by this point */ /** Routing failed */ if (return_code != 0) { bool router_can_continue; GWBUF* errbuf; /** * Create error to be sent to client if session * can't be continued. */ errbuf = mysql_create_custom_error(1, 0, "Routing failed. Session is closed."); /** * Ensure that there are enough backends * available for router to continue operation. */ session->service->router->handleError(session->service->router_instance, session->router_session, errbuf, dcb, ERRACT_NEW_CONNECTION, &router_can_continue); gwbuf_free(errbuf); /** * If the router cannot continue, close session */ if (!router_can_continue) { MXS_ERROR("Routing the query failed. " "Session will be closed."); } } if (proto->current_command == MYSQL_COM_QUIT) { /** Close router session which causes closing of backends */ dcb_close(dcb); } return return_code; } /** * @brief Analyse authentication errors and write appropriate log messages * * @param dcb Request handler DCB connected to the client * @param auth_val The type of authentication failure * @note Authentication status codes are defined in maxscale/protocol/mysql.h */ static void mysql_client_auth_error_handling(DCB *dcb, int auth_val, int packet_number) { int message_len; char *fail_str = NULL; MYSQL_session *session = (MYSQL_session*)dcb->data; switch (auth_val) { case MXS_AUTH_NO_SESSION: MXS_DEBUG("%lu [gw_read_client_event] session creation failed. fd %d, " "state = MYSQL_AUTH_NO_SESSION.", pthread_self(), dcb->fd); /** Send ERR 1045 to client */ mysql_send_auth_error(dcb, packet_number, 0, "failed to create new session"); break; case MXS_AUTH_FAILED_DB: MXS_DEBUG("%lu [gw_read_client_event] database specified was not valid. fd %d, " "state = MYSQL_FAILED_AUTH_DB.", pthread_self(), dcb->fd); /** Send error 1049 to client */ message_len = 25 + MYSQL_DATABASE_MAXLEN; fail_str = MXS_CALLOC(1, message_len + 1); MXS_ABORT_IF_NULL(fail_str); snprintf(fail_str, message_len, "Unknown database '%s'", session->db); modutil_send_mysql_err_packet(dcb, packet_number, 0, 1049, "42000", fail_str); break; case MXS_AUTH_FAILED_SSL: MXS_DEBUG("%lu [gw_read_client_event] client is " "not SSL capable for SSL listener. fd %d, " "state = MYSQL_FAILED_AUTH_SSL.", pthread_self(), dcb->fd); /** Send ERR 1045 to client */ mysql_send_auth_error(dcb, packet_number, 0, "Access without SSL denied"); break; case MXS_AUTH_SSL_INCOMPLETE: MXS_DEBUG("%lu [gw_read_client_event] unable to " "complete SSL authentication. fd %d, " "state = MYSQL_AUTH_SSL_INCOMPLETE.", pthread_self(), dcb->fd); /** Send ERR 1045 to client */ mysql_send_auth_error(dcb, packet_number, 0, "failed to complete SSL authentication"); break; case MXS_AUTH_FAILED: MXS_DEBUG("%lu [gw_read_client_event] authentication failed. fd %d, " "state = MYSQL_FAILED_AUTH.", pthread_self(), dcb->fd); /** Send error 1045 to client */ fail_str = create_auth_fail_str(session->user, dcb->remote, session->auth_token_len > 0, session->db, auth_val); modutil_send_mysql_err_packet(dcb, packet_number, 0, 1045, "28000", fail_str); break; default: MXS_DEBUG("%lu [gw_read_client_event] authentication failed. fd %d, " "state unrecognized.", pthread_self(), dcb->fd); /** Send error 1045 to client */ fail_str = create_auth_fail_str(session->user, dcb->remote, session->auth_token_len > 0, session->db, auth_val); modutil_send_mysql_err_packet(dcb, packet_number, 0, 1045, "28000", fail_str); } MXS_FREE(fail_str); } static int gw_connection_limit(DCB *dcb, int limit) { return mysql_send_standard_error(dcb, 0, 1040, "Too many connections"); } /////////////////////////////////////////////// // client write event to Client triggered by EPOLLOUT ////////////////////////////////////////////// /** * @node Client's fd became writable, and EPOLLOUT event * arrived. As a consequence, client input buffer (writeq) is flushed. * * Parameters: * @param dcb - in, use * client dcb * * @return constantly 1 * * * @details (write detailed description here) * */ int gw_write_client_event(DCB *dcb) { MySQLProtocol *protocol = NULL; CHK_DCB(dcb); ss_dassert(dcb->state != DCB_STATE_DISCONNECTED); if (dcb == NULL) { goto return_1; } if (dcb->state == DCB_STATE_DISCONNECTED) { goto return_1; } if (dcb->protocol == NULL) { goto return_1; } protocol = (MySQLProtocol *)dcb->protocol; CHK_PROTOCOL(protocol); if (protocol->protocol_auth_state == MXS_AUTH_STATE_COMPLETE) { dcb_drain_writeq(dcb); goto return_1; } return_1: #if defined(SS_DEBUG) if (dcb->state == DCB_STATE_POLLING || dcb->state == DCB_STATE_NOPOLLING || dcb->state == DCB_STATE_ZOMBIE) { CHK_PROTOCOL(protocol); } #endif return 1; } /** * Bind the DCB to a network port or a UNIX Domain Socket. * @param listen_dcb Listener DCB * @param config_bind Bind address in either IP:PORT format for network sockets or PATH * for UNIX Domain Sockets * @return 1 on success, 0 on error */ int gw_MySQLListener(DCB *listen_dcb, char *config_bind) { if (dcb_listen(listen_dcb, config_bind, "MySQL") < 0) { return 0; } listen_dcb->func.accept = gw_MySQLAccept; return 1; } /** * @node Accept a new connection, using the DCB code for the basic work * * For as long as dcb_accept can return new client DCBs for new connections, * continue to loop. The code will always give a failure return, since it * continues to try to create new connections until a failure occurs. * * @param listener - The Listener DCB that picks up new connection requests * @return 0 in success, 1 in failure * */ int gw_MySQLAccept(DCB *listener) { DCB *client_dcb; MySQLProtocol *protocol; CHK_DCB(listener); if (DCB_STATE_WAITING == listener->state) { gw_process_one_new_client(listener); } else { while ((client_dcb = dcb_accept(listener)) != NULL) { gw_process_one_new_client(client_dcb); } /**< while client_dcb != NULL */ } /* Must have broken out of while loop or received NULL client_dcb */ return 1; } static void gw_process_one_new_client(DCB *client_dcb) { MySQLProtocol *protocol; CHK_DCB(client_dcb); protocol = mysql_protocol_init(client_dcb, client_dcb->fd); if (protocol == NULL) { /** delete client_dcb */ dcb_close(client_dcb); MXS_ERROR("%lu [gw_MySQLAccept] Failed to create " "protocol object for client connection.", pthread_self()); return; } CHK_PROTOCOL(protocol); client_dcb->protocol = protocol; if (DCB_STATE_WAITING == client_dcb->state) { client_dcb->state = DCB_STATE_ALLOC; } else { atomic_add(&client_dcb->service->client_count, 1); } //send handshake to the client_dcb MySQLSendHandshake(client_dcb); // client protocol state change protocol->protocol_auth_state = MXS_AUTH_STATE_MESSAGE_READ; /** * Set new descriptor to event set. At the same time, * change state to DCB_STATE_POLLING so that * thread which wakes up sees correct state. */ if (poll_add_dcb(client_dcb) == -1) { /* Send a custom error as MySQL command reply */ mysql_send_custom_error(client_dcb, 1, 0, "MaxScale encountered system limit while " "attempting to register on an epoll instance."); /** close client_dcb */ dcb_close(client_dcb); /** Previous state is recovered in poll_add_dcb. */ MXS_ERROR("%lu [gw_MySQLAccept] Failed to add dcb %p for " "fd %d to epoll set.", pthread_self(), client_dcb, client_dcb->fd); return; } else { MXS_DEBUG("%lu [gw_MySQLAccept] Added dcb %p for fd " "%d to epoll set.", pthread_self(), client_dcb, client_dcb->fd); } return; } static int gw_error_client_event(DCB* dcb) { MXS_SESSION* session; CHK_DCB(dcb); session = dcb->session; MXS_DEBUG("%lu [gw_error_client_event] Error event handling for DCB %p " "in state %s, session %p.", pthread_self(), dcb, STRDCBSTATE(dcb->state), (session != NULL ? session : NULL)); if (session != NULL && session->state == SESSION_STATE_STOPPING) { goto retblock; } #if defined(SS_DEBUG) MXS_DEBUG("Client error event handling."); #endif dcb_close(dcb); retblock: return 1; } static int gw_client_close(DCB *dcb) { MXS_SESSION* session; MXS_ROUTER_OBJECT* router; void* router_instance; #if defined(SS_DEBUG) MySQLProtocol* protocol = (MySQLProtocol *)dcb->protocol; if (dcb->state == DCB_STATE_POLLING || dcb->state == DCB_STATE_NOPOLLING || dcb->state == DCB_STATE_ZOMBIE) { if (!DCB_IS_CLONE(dcb)) { CHK_PROTOCOL(protocol); } } #endif MXS_DEBUG("%lu [gw_client_close]", pthread_self()); mysql_protocol_done(dcb); session = dcb->session; /** * session may be NULL if session_alloc failed. * In that case, router session wasn't created. */ if (session != NULL && SESSION_STATE_DUMMY != session->state) { CHK_SESSION(session); if (session->state != SESSION_STATE_STOPPING) { session->state = SESSION_STATE_STOPPING; } router_instance = session->service->router_instance; router = session->service->router; /** * If router session is being created concurrently router * session might be NULL and it shouldn't be closed. */ if (session->router_session != NULL) { /** Close router session and all its connections */ router->closeSession(router_instance, session->router_session); } } return 1; } /** * Handle a hangup event on the client side descriptor. * * We simply close the DCB, this will propagate the closure to any * backend descriptors and perform the session cleanup. * * @param dcb The DCB of the connection */ static int gw_client_hangup_event(DCB *dcb) { MXS_SESSION* session; CHK_DCB(dcb); session = dcb->session; if (session != NULL && session->state == SESSION_STATE_ROUTER_READY) { CHK_SESSION(session); } if (session != NULL && session->state == SESSION_STATE_STOPPING) { goto retblock; } if (!session_valid_for_pool(session)) { // The client did not send a COM_QUIT packet modutil_send_mysql_err_packet(dcb, 0, 0, 1927, "08S01", "Connection killed by MaxScale"); } dcb_close(dcb); retblock: return 1; } /** * Update protocol tracking information for an individual statement * * @param dcb Client DCB * @param buffer Buffer containing a single packet */ void update_current_command(DCB* dcb, GWBUF* buffer) { MySQLProtocol *proto = (MySQLProtocol*)dcb->protocol; uint8_t cmd = (uint8_t)MYSQL_COM_QUERY; /** * As we are routing individual packets, we can extract the command byte here. * Empty packets are treated as COM_QUERY packets by default. */ gwbuf_copy_data(buffer, MYSQL_HEADER_LEN, 1, &cmd); proto->current_command = cmd; /** * Now that we have the current command, we can check if this connection * can be a candidate for the connection pool. */ check_pool_candidate(dcb); } /** * Detect if buffer includes partial mysql packet or multiple packets. * Store partial packet to dcb_readqueue. Send complete packets one by one * to router. * * It is assumed readbuf includes at least one complete packet. * Return 1 in success. If the last packet is incomplete return success but * leave incomplete packet to readbuf. * * @param session Session pointer * @param capabilities The capabilities of the service. * @param p_readbuf Pointer to the address of GWBUF including the query * * @return 1 if succeed, */ static int route_by_statement(MXS_SESSION* session, uint64_t capabilities, GWBUF** p_readbuf) { int rc; GWBUF* packetbuf; #if defined(SS_DEBUG) GWBUF* tmpbuf; tmpbuf = *p_readbuf; while (tmpbuf != NULL) { ss_dassert(GWBUF_IS_TYPE_MYSQL(tmpbuf)); tmpbuf = tmpbuf->next; } #endif do { ss_dassert(GWBUF_IS_TYPE_MYSQL((*p_readbuf))); /** * Collect incoming bytes to a buffer until complete packet has * arrived and then return the buffer. */ // TODO: This should be replaced with modutil_get_next_MySQL_packet. packetbuf = gw_MySQL_get_next_packet(p_readbuf); if (packetbuf != NULL) { CHK_GWBUF(packetbuf); ss_dassert(GWBUF_IS_TYPE_MYSQL(packetbuf)); /** * This means that buffer includes exactly one MySQL * statement. * backend func.write uses the information. MySQL backend * protocol, for example, stores the command identifier * to protocol structure. When some other thread reads * the corresponding response the command tells how to * handle response. * * Set it here instead of gw_read_client_event to make * sure it is set to each (MySQL) packet. */ gwbuf_set_type(packetbuf, GWBUF_TYPE_SINGLE_STMT); /** * Update the currently command being executed. */ update_current_command(session->client_dcb, packetbuf); if (rcap_type_required(capabilities, RCAP_TYPE_CONTIGUOUS_INPUT)) { if (!GWBUF_IS_CONTIGUOUS(packetbuf)) { // TODO: As long as gw_MySQL_get_next_packet is used above, the buffer // TODO: will be contiguous. That function should be replaced with // TODO: modutil_get_next_MySQL_packet. GWBUF* tmp = gwbuf_make_contiguous(packetbuf); if (tmp) { packetbuf = tmp; } else { // TODO: A memory allocation failure. We should close the dcb // TODO: and terminate the session. rc = 0; goto return_rc; } } if (rcap_type_required(capabilities, RCAP_TYPE_TRANSACTION_TRACKING)) { uint8_t *data = GWBUF_DATA(packetbuf); if (session_trx_is_ending(session)) { session_set_trx_state(session, SESSION_TRX_INACTIVE); } if (MYSQL_GET_COMMAND(data) == MYSQL_COM_QUERY) { uint32_t type = qc_get_trx_type_mask(packetbuf); if (type & QUERY_TYPE_BEGIN_TRX) { if (type & QUERY_TYPE_DISABLE_AUTOCOMMIT) { session_set_autocommit(session, false); session_set_trx_state(session, SESSION_TRX_INACTIVE); } else { mxs_session_trx_state_t trx_state; if (type & QUERY_TYPE_WRITE) { trx_state = SESSION_TRX_READ_WRITE; } else if (type & QUERY_TYPE_READ) { trx_state = SESSION_TRX_READ_ONLY; } else { trx_state = SESSION_TRX_ACTIVE; } session_set_trx_state(session, trx_state); } } else if ((type & QUERY_TYPE_COMMIT) || (type & QUERY_TYPE_ROLLBACK)) { mxs_session_trx_state_t trx_state = session_get_trx_state(session); trx_state |= SESSION_TRX_ENDING_BIT; session_set_trx_state(session, trx_state); if (type & QUERY_TYPE_ENABLE_AUTOCOMMIT) { session_set_autocommit(session, true); } } } } } /** Route query */ rc = MXS_SESSION_ROUTE_QUERY(session, packetbuf); } else { rc = 1; goto return_rc; } } while (rc == 1 && *p_readbuf != NULL); return_rc: return rc; }