Initial maweb backend

6 files changed, 1200 insertions, 0 deletions

diff --git a/backends/Makefile b/backends/Makefile
index 2635ddc..582655c 100644
--- a/backends/Makefile
+++ b/backends/Makefile
@@ -33,8 +33,10 @@ sacn.dll: ADDITIONAL_OBJS += $(BACKEND_LIB)
 sacn.dll: LDLIBS += -lws2_32
 
 maweb.so: ADDITIONAL_OBJS += $(BACKEND_LIB)
+maweb.so: LDLIBS = -lssl
 maweb.dll: ADDITIONAL_OBJS += $(BACKEND_LIB)
 maweb.dll: LDLIBS += -lws2_32
+maweb.dll: CFLAGS += -DMAWEB_NO_LIBSSL
 
 midi.so: LDLIBS = -lasound
 evdev.so: CFLAGS += $(shell pkg-config --cflags libevdev)
diff --git a/backends/libmmbackend.c b/backends/libmmbackend.c
index 2fd3b8b..c98cfe3 100644
--- a/backends/libmmbackend.c
+++ b/backends/libmmbackend.c
@@ -151,3 +151,220 @@ int mmbackend_send(int fd, uint8_t* data, size_t length){
 int mmbackend_send_str(int fd, char* data){
 	return mmbackend_send(fd, (uint8_t*) data, strlen(data));
 }
+
+json_type json_identify(char* json, size_t length){
+	size_t n;
+
+	//skip leading blanks
+	for(n = 0; json[n] && n < length && isspace(json[n]); n++){
+	}
+
+	if(n == length){
+		return JSON_INVALID;
+	}
+
+	switch(json[n]){
+		case '{':
+			return JSON_OBJECT;
+		case '[':
+			return JSON_ARRAY;
+		case '"':
+			return JSON_STRING;
+		case '-':
+		case '+':
+			return JSON_NUMBER;
+		default:
+			//true false null number
+			if(!strncmp(json + n, "true", 4)
+					|| !strncmp(json + n, "false", 5)){
+				return JSON_BOOL;
+			}
+			else if(!strncmp(json + n, "null", 4)){
+				return JSON_NULL;
+			}
+			//a bit simplistic but it should do
+			if(isdigit(json[n])){
+				return JSON_NUMBER;
+			}
+	}
+	return JSON_INVALID;
+}
+
+size_t json_validate(char* json, size_t length){
+	switch(json_identify(json, length)){
+		case JSON_STRING:
+			return json_validate_string(json, length);
+		case JSON_ARRAY:
+			return json_validate_array(json, length);
+		case JSON_OBJECT:
+			return json_validate_object(json, length);
+		case JSON_INVALID:
+			return 0;
+		default:
+			return json_validate_value(json, length);
+	}
+}
+
+size_t json_validate_string(char* json, size_t length){
+	size_t string_length = 0, offset;
+
+	for(offset = 0; json[offset] && offset < length && json[offset] != '"'; offset++){
+	}
+
+	if(offset == length){
+		return 0;
+	}
+
+	//find terminating quotation mark not preceded by escape
+	for(string_length = 1; offset + string_length < length
+			&& isprint(json[offset + string_length])
+			&& (json[offset + string_length] != '"' || json[offset + string_length - 1] == '\\'); string_length++){
+	}
+
+	//complete string found
+	if(json[offset + string_length] == '"' && json[offset + string_length - 1] != '\\'){
+		return offset + string_length + 1;
+	}
+
+	return 0;
+}
+
+size_t json_validate_array(char* json, size_t length){
+	//TODO
+	return 0;
+}
+
+size_t json_validate_object(char* json, size_t length){
+	//TODO
+	return 0;
+}
+
+size_t json_validate_value(char* json, size_t length){
+	//TODO
+	return 0;
+}
+
+size_t json_obj_offset(char* json, char* key){
+	size_t offset = 0;
+	uint8_t match = 0;
+
+	//skip whitespace
+	for(offset = 0; json[offset] && isspace(json[offset]); offset++){
+	}
+
+	if(json[offset] != '{'){
+		return 0;
+	}
+	offset++;
+
+	while(json_identify(json + offset, strlen(json + offset)) == JSON_STRING){
+		//skip to key begin
+		for(; json[offset] && json[offset] != '"'; offset++){
+		}
+
+		if(!strncmp(json + offset + 1, key, strlen(key)) && json[offset + 1 + strlen(key)] == '"'){
+			//key found
+			match = 1;
+		}
+
+		offset += json_validate_string(json + offset, strlen(json + offset));
+
+		//skip to value separator
+		for(; json[offset] && json[offset] != ':'; offset++){
+		}
+
+		//skip whitespace
+		for(offset++; json[offset] && isspace(json[offset]); offset++){
+		}
+
+		if(match){
+			return offset;
+		}
+
+		//add length of value
+		offset += json_validate(json + offset, strlen(json + offset));
+
+		//find comma or closing brace
+		for(; json[offset] && json[offset] != ',' && json[offset] != '}'; offset++){
+		}
+
+		if(json[offset] == ','){
+			offset++;
+		}
+	}
+
+	return 0;
+}
+
+json_type json_obj(char* json, char* key){
+	size_t offset = json_obj_offset(json, key);
+	if(offset){
+		return json_identify(json + offset, strlen(json + offset));
+	}
+	return JSON_INVALID;
+}
+
+uint8_t json_obj_bool(char* json, char* key, uint8_t fallback){
+	size_t offset = json_obj_offset(json, key);
+	if(offset){
+		if(!strncmp(json + offset, "true", 4)){
+			return 1;
+		}
+		if(!strncmp(json + offset, "false", 5)){
+			return 0;
+		}
+	}
+	return fallback;
+}
+
+int64_t json_obj_int(char* json, char* key, int64_t fallback){
+	char* next_token = NULL;
+	int64_t result;
+	size_t offset = json_obj_offset(json, key);
+	if(offset){
+		result = strtol(json + offset, &next_token, 10);
+		if(next_token != json + offset){
+			return result;
+		}
+	}
+	return fallback;
+}
+
+double json_obj_double(char* json, char* key, double fallback){
+	char* next_token = NULL;
+	int64_t result;
+	size_t offset = json_obj_offset(json, key);
+	if(offset){
+		result = strtod(json + offset, &next_token);
+		if(next_token != json + offset){
+			return result;
+		}
+	}
+	return fallback;
+}
+
+char* json_obj_str(char* json, char* key, size_t* length){
+	size_t offset = json_obj_offset(json, key), raw_length;
+	if(offset){
+		raw_length = json_validate_string(json + offset, strlen(json + offset));
+		if(length){
+			*length = raw_length - 2;
+		}
+		return json + offset + 1;
+	}
+	return NULL;
+}
+
+char* json_obj_strdup(char* json, char* key){
+	size_t offset = json_obj_offset(json, key), raw_length;
+	char* rv = NULL;
+	if(offset){
+		raw_length = json_validate_string(json + offset, strlen(json + offset));
+		rv = calloc(raw_length - 1, sizeof(char));
+		if(rv){
+			memcpy(rv, json + offset + 1, raw_length - 2);
+		}
+		return rv;
+	}
+	return NULL;
+}
diff --git a/backends/libmmbackend.h b/backends/libmmbackend.h
index 31c4b96..aa0ac0c 100644
--- a/backends/libmmbackend.h
+++ b/backends/libmmbackend.h
@@ -16,6 +16,10 @@
 #include <fcntl.h>
 #include "../portability.h"
 
+/*** BACKEND IMPLEMENTATION LIBRARY ***/
+
+/** Networking functions **/
+
 /* 
  * Parse spec as host specification in the form
  *	host port
@@ -49,3 +53,74 @@ int mmbackend_send(int fd, uint8_t* data, size_t length);
  * Wraps mmbackend_send for cstrings
  */
 int mmbackend_send_str(int fd, char* data);
+
+
+/** JSON parsing **/
+
+typedef enum /*_json_types*/ {
+	JSON_INVALID = 0,
+	JSON_STRING,
+	JSON_ARRAY,
+	JSON_OBJECT,
+	JSON_NUMBER,
+	JSON_BOOL,
+	JSON_NULL
+} json_type;
+
+/* 
+ * Try to identify the type of JSON data next in the buffer
+ * Will access at most the next `length` bytes
+ */
+json_type json_identify(char* json, size_t length);
+
+/* 
+ * Validate that a buffer contains a valid JSON document/data within `length` bytes
+ * Returns the length of a detected JSON document, 0 otherwise (ie. parse failures)
+ */
+size_t json_validate(char* json, size_t length);
+
+size_t json_validate_string(char* json, size_t length);
+
+size_t json_validate_array(char* json, size_t length);
+
+size_t json_validate_object(char* json, size_t length);
+
+size_t json_validate_value(char* json, size_t length);
+
+/* 
+ * Calculate offset for value of `key`
+ * Assumes a zero-terminated, validated JSON object as input
+ * Returns offset on success, 0 on failure
+ */
+size_t json_obj_offset(char* json, char* key);
+
+/*
+ * Check for for a key within a JSON object
+ * Assumes a zero-terminated, validated JSON object as input
+ * Returns type of value
+ */
+json_type json_obj(char* json, char* key);
+
+//json_type json_array(char* json, size_t index)
+
+/*
+ * Fetch boolean value for an object key
+ * Assumes a zero-terminated, validated JSON object as input
+ */
+uint8_t json_obj_bool(char* json, char* key, uint8_t fallback);
+
+/*
+ * Fetch integer/double value for an object key
+ * Assumes a zero-terminated validated JSON object as input
+ */
+int64_t json_obj_int(char* json, char* key, int64_t fallback);
+double json_obj_double(char* json, char* key, double fallback);
+
+/* 
+ * Fetch a string value for an object key
+ * Assumes a zero-terminated validated JSON object as input
+ * json_obj_strdup returns a newly-allocated buffer containing
+ * only the requested value
+ */
+char* json_obj_str(char* json, char* key, size_t* length);
+char* json_obj_strdup(char* json, char* key);
diff --git a/backends/maweb.c b/backends/maweb.c
new file mode 100644
index 0000000..be4c2ac
--- /dev/null
+++ b/backends/maweb.c
@@ -0,0 +1,695 @@
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#ifndef MAWEB_NO_LIBSSL
+#include <openssl/md5.h>
+#endif
+
+#include "libmmbackend.h"
+#include "maweb.h"
+
+#define BACKEND_NAME "maweb"
+#define WS_LEN(a) ((a) & 0x7F)
+#define WS_OP(a) ((a) & 0x0F)
+#define WS_FLAG_FIN 0x80
+#define WS_FLAG_MASK 0x80
+
+static uint64_t last_keepalive = 0;
+
+static char* cmdline_keys[] = {
+	"SET",
+	"PREV",
+	"NEXT",
+	"CLEAR",
+	"FIXTURE_CHANNEL",
+	"FIXTURE_GROUP_PRESET",
+	"EXEC_CUE",
+	"STORE_UPDATE",
+	"OOPS",
+	"ESC",
+	"0",
+	"1",
+	"2",
+	"3",
+	"4",
+	"5",
+	"6",
+	"7",
+	"8",
+	"9",
+	"PUNKT",
+	"PLUS",
+	"MINUS",
+	"THRU",
+	"IF",
+	"AT",
+	"FULL",
+	"HIGH",
+	"ENTER",
+	"OFF",
+	"ON",
+	"ASSIGN",
+	"LABEL",
+	"COPY",
+	"TIME",
+	"PAGE",
+	"MACRO",
+	"DELETE",
+	"GOTO",
+	"GO_PLUS",
+	"GO_MINUS",
+	"PAUSE",
+	"SELECT",
+	"FIXTURE",
+	"SEQU",
+	"CUE",
+	"PRESET",
+	"EDIT",
+	"UPDATE",
+	"EXEC",
+	"STORE",
+	"GROUP",
+	"PROG_ONLY",
+	"SPECIAL_DIALOGUE",
+	"SOLO",
+	"ODD",
+	"EVEN",
+	"WINGS",
+	"RESET",
+	"MA",
+	"layerMode",
+	"featureSort",
+	"fixtureSort",
+	"channelSort",
+	"hideName"
+};
+
+int init(){
+	backend maweb = {
+		.name = BACKEND_NAME,
+		.conf = maweb_configure,
+		.create = maweb_instance,
+		.conf_instance = maweb_configure_instance,
+		.channel = maweb_channel,
+		.handle = maweb_set,
+		.process = maweb_handle,
+		.start = maweb_start,
+		.shutdown = maweb_shutdown
+	};
+
+	if(sizeof(maweb_channel_ident) != sizeof(uint64_t)){
+		fprintf(stderr, "maweb channel identification union out of bounds\n");
+		return 1;
+	}
+
+	//register backend
+	if(mm_backend_register(maweb)){
+		fprintf(stderr, "Failed to register maweb backend\n");
+		return 1;
+	}
+	return 0;
+}
+
+static int maweb_configure(char* option, char* value){
+	fprintf(stderr, "The maweb backend does not take any global configuration\n");
+	return 1;
+}
+
+static int maweb_configure_instance(instance* inst, char* option, char* value){
+	maweb_instance_data* data = (maweb_instance_data*) inst->impl;
+	char* host = NULL, *port = NULL;
+	#ifndef MAWEB_NO_LIBSSL
+	uint8_t password_hash[MD5_DIGEST_LENGTH];
+	#endif
+
+	if(!strcmp(option, "host")){
+		mmbackend_parse_hostspec(value, &host, &port);
+		if(!host){
+			fprintf(stderr, "Invalid host specified for maweb instance %s\n", inst->name);
+			return 1;
+		}
+		free(data->host);
+		data->host = strdup(host);
+		free(data->port);
+		data->port = NULL;
+		if(port){
+			data->port = strdup(port);
+		}
+		return 0;
+	}
+	else if(!strcmp(option, "user")){
+		free(data->user);
+		data->user = strdup(value);
+		return 0;
+	}
+	else if(!strcmp(option, "password")){
+		#ifndef MAWEB_NO_LIBSSL
+		size_t n;
+		MD5((uint8_t*) value, strlen(value), (uint8_t*) password_hash);
+		data->pass = realloc(data->pass, (2 * MD5_DIGEST_LENGTH + 1) * sizeof(char));
+		for(n = 0; n < MD5_DIGEST_LENGTH; n++){
+			snprintf(data->pass + 2 * n, 3, "%02x", password_hash[n]);
+		}
+		return 0;
+		#else
+		fprintf(stderr, "This build of the maweb backend only supports the default password\n");
+		return 1;
+		#endif
+	}
+
+	fprintf(stderr, "Unknown configuration parameter %s for manet instance %s\n", option, inst->name);
+	return 1;
+}
+
+static instance* maweb_instance(){
+	instance* inst = mm_instance();
+	if(!inst){
+		return NULL;
+	}
+
+	maweb_instance_data* data = calloc(1, sizeof(maweb_instance_data));
+	if(!data){
+		fprintf(stderr, "Failed to allocate memory\n");
+		return NULL;
+	}
+
+	data->fd = -1;
+	data->buffer = calloc(MAWEB_RECV_CHUNK, sizeof(uint8_t));
+	if(!data->buffer){
+		fprintf(stderr, "Failed to allocate memory\n");
+		free(data);
+		return NULL;
+	}
+	data->allocated = MAWEB_RECV_CHUNK;
+
+	inst->impl = data;
+	return inst;
+}
+
+static channel* maweb_channel(instance* inst, char* spec){
+	maweb_channel_ident ident = {
+		.label = 0
+	};
+	char* next_token = NULL;
+	size_t n;
+
+	if(!strncmp(spec, "page", 4)){
+		ident.fields.page = strtoul(spec + 4, &next_token, 10);
+		if(*next_token != '.'){
+			fprintf(stderr, "Failed to parse maweb channel spec %s: Missing separator\n", spec);
+			return NULL;
+		}
+
+		next_token++;
+		if(!strncmp(next_token, "fader", 5)){
+			ident.fields.type = exec_fader;
+			next_token += 5;
+		}
+		else if(!strncmp(next_token, "upper", 5)){
+			ident.fields.type = exec_upper;
+			next_token += 5;
+		}
+		else if(!strncmp(next_token, "lower", 5)){
+			ident.fields.type = exec_lower;
+			next_token += 5;
+		}
+		else if(!strncmp(next_token, "flash", 5)){
+			ident.fields.type = exec_flash;
+			next_token += 5;
+		}
+		else if(!strncmp(next_token, "button", 6)){
+			ident.fields.type = exec_fader;
+			next_token += 6;
+		}
+		ident.fields.index = strtoul(next_token, NULL, 10);
+	}
+	else{
+		for(n = 0; n < sizeof(cmdline_keys) / sizeof(char*); n++){
+			if(!strcmp(spec, cmdline_keys[n])){
+				ident.fields.type = cmdline_button;
+				ident.fields.index = n + 1;
+				ident.fields.page = 1;
+				break;
+			}
+		}
+	}
+
+	if(ident.fields.type && ident.fields.index && ident.fields.page
+			&& ident.fields.index <= 90){
+		//actually, those are zero-indexed...
+		ident.fields.index--;
+		ident.fields.page--;
+		return mm_channel(inst, ident.label, 1);
+	}
+	fprintf(stderr, "Failed to parse maweb channel spec %s\n", spec);
+	return NULL;
+}
+
+static int maweb_send_frame(instance* inst, maweb_operation op, uint8_t* payload, size_t len){
+	maweb_instance_data* data = (maweb_instance_data*) inst->impl;
+	uint8_t frame_header[MAWEB_FRAME_HEADER_LENGTH] = "";
+	size_t header_bytes = 2;
+	uint16_t* payload_len16 = (uint16_t*) (frame_header + 2);
+	uint64_t* payload_len64 = (uint64_t*) (frame_header + 2);
+
+	frame_header[0] = WS_FLAG_FIN | op;
+	if(len <= 125){
+		frame_header[1] = WS_FLAG_MASK | len;
+	}
+	else if(len <= 0xFFFF){
+		frame_header[1] = WS_FLAG_MASK | 126;
+		*payload_len16 = htobe16(len);
+		header_bytes += 2;
+	}
+	else{
+		frame_header[1] = WS_FLAG_MASK | 127;
+		*payload_len64 = htobe64(len);
+		header_bytes += 8;
+	}
+	//send a zero masking key because masking is stupid
+	header_bytes += 4;
+
+	if(mmbackend_send(data->fd, frame_header, header_bytes)
+			|| mmbackend_send(data->fd, payload, len)){
+		return 1;
+	}
+
+	return 0;
+}
+
+static int maweb_handle_message(instance* inst, char* payload, size_t payload_length){
+	char xmit_buffer[MAWEB_XMIT_CHUNK];
+	char* field;
+	maweb_instance_data* data = (maweb_instance_data*) inst->impl;
+
+	fprintf(stderr, "maweb message (%lu): %s\n", payload_length, payload);
+	if(json_obj(payload, "session") == JSON_NUMBER){
+		data->session = json_obj_int(payload, "session", data->session);
+		fprintf(stderr, "maweb session id is now %ld\n", data->session);
+	}
+
+	if(json_obj_bool(payload, "forceLogin", 0)){
+		fprintf(stderr, "maweb sending user credentials\n");
+		snprintf(xmit_buffer, sizeof(xmit_buffer),
+				"{\"requestType\":\"login\",\"username\":\"%s\",\"password\":\"%s\",\"session\":%ld}",
+				data->user, data->pass, data->session);
+		maweb_send_frame(inst, ws_text, (uint8_t*) xmit_buffer, strlen(xmit_buffer));
+	}
+
+	if(json_obj(payload, "status") && json_obj(payload, "appType")){
+		fprintf(stderr, "maweb connection established\n");
+		maweb_send_frame(inst, ws_text, (uint8_t*) "{\"session\":0}", 13);
+	}
+
+	if(json_obj(payload, "responseType") == JSON_STRING){
+		field = json_obj_str(payload, "responseType", NULL);
+		if(!strncmp(field, "login", 5)){
+			if(json_obj_bool(payload, "result", 0)){
+				fprintf(stderr, "maweb login successful\n");
+				data->login = 1;
+			}
+			else{
+				fprintf(stderr, "maweb login failed\n");
+				data->login = 0;
+			}
+		}
+		else if(!strncmp(field, "getdata", 7)){
+			//FIXME stupid keepalive logic
+			snprintf(xmit_buffer, sizeof(xmit_buffer),
+					"{\"requestType\":\"getdata\","
+					"\"data\":\"set,clear,solo,high\","
+					"\"realtime\":true,"
+					"\"maxRequests\":10,"
+					",\"session\":%ld}",
+					data->session);
+			maweb_send_frame(inst, ws_text, (uint8_t*) xmit_buffer, strlen(xmit_buffer));
+		}
+	}
+
+	return 0;
+}
+
+static int maweb_connect(instance* inst){
+	maweb_instance_data* data = (maweb_instance_data*) inst->impl;
+	if(!data->host){
+		return 1;
+	}
+
+	//unregister old fd from core
+	if(data->fd >= 0){
+		mm_manage_fd(data->fd, BACKEND_NAME, 0, NULL);
+	}
+
+	data->fd = mmbackend_socket(data->host, data->port ? data->port : MAWEB_DEFAULT_PORT, SOCK_STREAM, 0, 0);
+	if(data->fd < 0){
+		return 1;
+	}
+
+	data->state = ws_new;
+	if(mmbackend_send_str(data->fd, "GET /?ma=1 HTTP/1.1\r\n")
+			|| mmbackend_send_str(data->fd, "Connection: Upgrade\r\n")
+			|| mmbackend_send_str(data->fd, "Upgrade: websocket\r\n")
+			|| mmbackend_send_str(data->fd, "Sec-WebSocket-Version: 13\r\n")
+			//the websocket key probably should not be hardcoded, but this is not security criticial
+			//and the whole websocket 'accept key' dance is plenty stupid as it is
+			|| mmbackend_send_str(data->fd, "Sec-WebSocket-Key: rbEQrXMEvCm4ZUjkj6juBQ==\r\n")
+			|| mmbackend_send_str(data->fd, "\r\n")){
+		fprintf(stderr, "maweb backend failed to communicate with peer\n");
+		return 1;
+	}
+
+	//register new fd
+	if(mm_manage_fd(data->fd, BACKEND_NAME, 1, (void*) inst)){
+		fprintf(stderr, "maweb backend failed to register fd\n");
+		return 1;
+	}
+	return 0;
+}
+
+static ssize_t maweb_handle_lines(instance* inst, ssize_t bytes_read){
+	maweb_instance_data* data = (maweb_instance_data*) inst->impl;
+	size_t n, begin = 0;
+
+	for(n = 0; n < bytes_read - 2; n++){
+		if(!strncmp((char*) data->buffer + data->offset + n, "\r\n", 2)){
+			if(data->state == ws_new){
+				if(!strncmp((char*) data->buffer, "HTTP/1.1 101", 12)){
+					data->state = ws_http;
+				}
+				else{
+					fprintf(stderr, "maweb received invalid HTTP response for instance %s\n", inst->name);
+					return -1;
+				}
+			}
+			else{
+				//ignore all http stuff until the end of headers since we don't actually care...
+				if(n == begin){
+					data->state = ws_open;
+				}
+			}
+			begin = n + 2;
+		}
+	}
+
+	return begin;
+}
+
+static ssize_t maweb_handle_ws(instance* inst, ssize_t bytes_read){
+	maweb_instance_data* data = (maweb_instance_data*) inst->impl;
+	size_t header_length = 2;
+	uint64_t payload_length = 0;
+	uint16_t* payload_len16 = (uint16_t*) (data->buffer + 2);
+	uint64_t* payload_len64 = (uint64_t*) (data->buffer + 2);
+	uint8_t* payload = data->buffer + 2;
+	uint8_t terminator_temp = 0;
+
+	if(data->offset + bytes_read < 2){
+		return 0;
+	}
+
+	//using varint as payload length is stupid, but some people seem to think otherwise...
+	payload_length = WS_LEN(data->buffer[1]);
+	switch(payload_length){
+		case 126:
+			if(data->offset + bytes_read < 4){
+				return 0;
+			}
+			payload_length = htobe16(*payload_len16);
+			payload = data->buffer + 4;
+			header_length = 4;
+			break;
+		case 127:
+			if(data->offset + bytes_read < 10){
+				return 0;
+			}
+			payload_length = htobe64(*payload_len64);
+			payload = data->buffer + 10;
+			header_length = 10;
+			break;
+		default:
+			break;
+	}
+
+	if(data->offset + bytes_read < header_length + payload_length){
+		return 0;
+	}
+
+	switch(WS_OP(data->buffer[0])){
+		case ws_text:
+			//terminate message
+			terminator_temp = payload[payload_length];
+			payload[payload_length] = 0;
+			if(maweb_handle_message(inst, (char*) payload, payload_length)){
+				return data->offset + bytes_read;
+			}
+			payload[payload_length] = terminator_temp;
+			break;
+		case ws_ping:
+			//answer server ping with a pong
+			if(maweb_send_frame(inst, ws_pong, payload, payload_length)){
+				fprintf(stderr, "maweb failed to send pong\n");
+			}
+			return header_length + payload_length;
+		default:
+			fprintf(stderr, "maweb encountered unhandled frame type %02X\n", WS_OP(data->buffer[0]));
+			//this is somewhat dicey, it might be better to handle only header + payload length for known but unhandled types
+			return data->offset + bytes_read;
+	}
+
+	return header_length + payload_length;
+}
+
+static int maweb_handle_fd(instance* inst){
+	maweb_instance_data* data = (maweb_instance_data*) inst->impl;
+	ssize_t bytes_read, bytes_left = data->allocated - data->offset, bytes_handled;
+
+	if(bytes_left < 3){
+		data->buffer = realloc(data->buffer, (data->allocated + MAWEB_RECV_CHUNK) * sizeof(uint8_t));
+		if(!data->buffer){
+			fprintf(stderr, "Failed to allocate memory\n");
+			return 1;
+		}
+		data->allocated += MAWEB_RECV_CHUNK;
+		bytes_left += MAWEB_RECV_CHUNK;
+	}
+
+	bytes_read = recv(data->fd, data->buffer + data->offset, bytes_left - 1, 0);
+	if(bytes_read < 0){
+		fprintf(stderr, "maweb backend failed to receive: %s\n", strerror(errno));
+		//TODO close, reopen
+		return 1;
+	}
+	else if(bytes_read == 0){
+		//client closed connection
+		//TODO try to reopen
+		return 0;
+	}
+
+	do{
+		switch(data->state){
+			case ws_new:
+			case ws_http:
+				bytes_handled = maweb_handle_lines(inst, bytes_read);
+				break;
+			case ws_open:
+				bytes_handled = maweb_handle_ws(inst, bytes_read);
+				break;
+			case ws_closed:
+				bytes_handled = data->offset + bytes_read;
+				break;
+		}
+
+		if(bytes_handled < 0){
+			bytes_handled = data->offset + bytes_read;
+			//TODO close, reopen
+			fprintf(stderr, "maweb failed to handle incoming data\n");
+			return 1;
+		}
+		else if(bytes_handled == 0){
+			 break;
+		}
+
+		memmove(data->buffer, data->buffer + bytes_handled, (data->offset + bytes_read) - bytes_handled);
+
+		//FIXME this might be somewhat borked
+		bytes_read -= data->offset;
+		bytes_handled -= data->offset;
+		bytes_read -= bytes_handled;
+		data->offset = 0;
+	} while(bytes_read > 0);
+
+	data->offset += bytes_read;
+	return 0;
+}
+
+static int maweb_set(instance* inst, size_t num, channel** c, channel_value* v){
+	maweb_instance_data* data = (maweb_instance_data*) inst->impl;
+	char xmit_buffer[MAWEB_XMIT_CHUNK];
+	maweb_channel_ident ident;
+	size_t n;
+
+	if(num && !data->login){
+		fprintf(stderr, "maweb instance %s can not send output, not logged in\n", inst->name);
+	}
+
+	for(n = 0; n < num; n++){
+		ident.label = c[n]->ident;
+		switch(ident.fields.type){
+			case exec_fader:
+				snprintf(xmit_buffer, sizeof(xmit_buffer),
+						"{\"requestType\":\"playbacks_userInput\","
+						"\"execIndex\":%d,"
+						"\"pageIndex\":%d,"
+						"\"faderValue\":%f,"
+						"\"type\":1,"
+						"\"session\":%ld"
+						"}", ident.fields.index, ident.fields.page, v[n].normalised, data->session);
+				fprintf(stderr, "maweb out %s\n", xmit_buffer);
+				maweb_send_frame(inst, ws_text, (uint8_t*) xmit_buffer, strlen(xmit_buffer));
+				break;
+			case exec_upper:
+			case exec_lower:
+			case exec_flash:
+				snprintf(xmit_buffer, sizeof(xmit_buffer),
+						"{\"requestType\":\"playbacks_userInput\","
+						//"\"cmdline\":\"\","
+						"\"execIndex\":%d,"
+						"\"pageIndex\":%d,"
+						"\"buttonId\":%d,"
+						"\"pressed\":%s,"
+						"\"released\":%s,"
+						"\"type\":0,"
+						"\"session\":%ld"
+						"}", ident.fields.index, ident.fields.page,
+						(exec_flash - ident.fields.type),
+						(v[n].normalised > 0.9) ? "true" : "false",
+						(v[n].normalised > 0.9) ? "false" : "true",
+						data->session);
+				fprintf(stderr, "maweb out %s\n", xmit_buffer);
+				maweb_send_frame(inst, ws_text, (uint8_t*) xmit_buffer, strlen(xmit_buffer));
+				break;
+			case cmdline_button:
+				snprintf(xmit_buffer, sizeof(xmit_buffer),
+						"{\"keyname\":\"%s\","
+						//"\"autoSubmit\":false,"
+						"\"value\":%d"
+						"}", cmdline_keys[ident.fields.index],
+						(v[n].normalised > 0.9) ? 1 : 0);
+				fprintf(stderr, "maweb out %s\n", xmit_buffer);
+				maweb_send_frame(inst, ws_text, (uint8_t*) xmit_buffer, strlen(xmit_buffer));
+				break;
+			default:
+				fprintf(stderr, "maweb control not yet implemented\n");
+				break;
+		}
+	}
+	return 0;
+}
+
+static int maweb_keepalive(){
+	size_t n, u;
+	instance** inst = NULL;
+	maweb_instance_data* data = NULL;
+	char xmit_buffer[MAWEB_XMIT_CHUNK];
+
+	//fetch all defined instances
+	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
+		fprintf(stderr, "Failed to fetch instance list\n");
+		return 1;
+	}
+
+	//send keep-alive messages for logged-in instances
+	for(u = 0; u < n; u++){
+		data = (maweb_instance_data*) inst[u]->impl;
+		if(data->login){
+			snprintf(xmit_buffer, sizeof(xmit_buffer), "{\"session\":%ld}", data->session);
+			maweb_send_frame(inst[u], ws_text, (uint8_t*) xmit_buffer, strlen(xmit_buffer));
+		}
+	}
+
+	free(inst);
+	return 0;
+}
+
+static int maweb_handle(size_t num, managed_fd* fds){
+	size_t n = 0;
+	int rv = 0;
+
+	for(n = 0; n < num; n++){
+		rv |= maweb_handle_fd((instance*) fds[n].impl);
+	}
+
+	if(last_keepalive && mm_timestamp() - last_keepalive >= MAWEB_CONNECTION_KEEPALIVE){
+		rv |= maweb_keepalive();
+		last_keepalive = mm_timestamp();
+	}
+
+	return rv;
+}
+
+static int maweb_start(){
+	size_t n, u;
+	instance** inst = NULL;
+
+	//fetch all defined instances
+	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
+		fprintf(stderr, "Failed to fetch instance list\n");
+		return 1;
+	}
+
+	for(u = 0; u < n; u++){
+		if(maweb_connect(inst[u])){
+			fprintf(stderr, "Failed to open connection to MA Web Remote for instance %s\n", inst[u]->name);
+			return 1;
+		}
+	}
+
+	free(inst);
+	if(!n){
+		return 0;
+	}
+
+	fprintf(stderr, "maweb backend registering %lu descriptors to core\n", n);
+
+	//initialize keepalive timeout
+	last_keepalive = mm_timestamp();
+	return 0;
+}
+
+static int maweb_shutdown(){
+	size_t n, u;
+	instance** inst = NULL;
+	maweb_instance_data* data = NULL;
+
+	//fetch all instances
+	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
+		fprintf(stderr, "Failed to fetch instance list\n");
+		return 1;
+	}
+
+	for(u = 0; u < n; u++){
+		data = (maweb_instance_data*) inst[u]->impl;
+		free(data->host);
+		data->host = NULL;
+		free(data->port);
+		data->port = NULL;
+		free(data->user);
+		data->user = NULL;
+		free(data->pass);
+		data->pass = NULL;
+
+		close(data->fd);
+		data->fd = -1;
+
+		free(data->buffer);
+		data->buffer = NULL;
+
+		data->offset = data->allocated = 0;
+		data->state = ws_new;
+	}
+
+	free(inst);
+
+	fprintf(stderr, "maweb backend shut down\n");
+	return 0;
+}
diff --git a/backends/maweb.h b/backends/maweb.h
new file mode 100644
index 0000000..6e6e652
--- /dev/null
+++ b/backends/maweb.h
@@ -0,0 +1,69 @@
+#include "midimonster.h"
+
+int init();
+static int maweb_configure(char* option, char* value);
+static int maweb_configure_instance(instance* inst, char* option, char* value);
+static instance* maweb_instance();
+static channel* maweb_channel(instance* inst, char* spec);
+static int maweb_set(instance* inst, size_t num, channel** c, channel_value* v);
+static int maweb_handle(size_t num, managed_fd* fds);
+static int maweb_start();
+static int maweb_shutdown();
+
+//Default login password: MD5("midimonster")
+#define MAWEB_DEFAULT_PASSWORD "2807623134739142b119aff358f8a219"
+#define MAWEB_DEFAULT_PORT "80"
+#define MAWEB_RECV_CHUNK 1024
+#define MAWEB_XMIT_CHUNK 2048
+#define MAWEB_FRAME_HEADER_LENGTH 16
+#define MAWEB_CONNECTION_KEEPALIVE 10000
+
+typedef enum /*_maweb_channel_type*/ {
+	type_unset = 0,
+	exec_fader = 1,
+	exec_button = 2,
+	exec_upper = 3,
+	exec_lower = 4,
+	exec_flash = 5,
+	cmdline_button
+} maweb_channel_type;
+
+typedef enum /*_ws_conn_state*/ {
+	ws_new,
+	ws_http,
+	ws_open,
+	ws_closed
+} maweb_state;
+
+typedef enum /*_ws_frame_op*/ {
+	ws_text = 1,
+	ws_binary = 2,
+	ws_ping = 9,
+	ws_pong = 10
+} maweb_operation;
+
+typedef union {
+	struct {
+		uint8_t padding[3];
+		uint8_t type;
+		uint16_t page;
+		uint16_t index;
+	} fields;
+	uint64_t label;
+} maweb_channel_ident;
+
+typedef struct /*_maweb_instance_data*/ {
+	char* host;
+	char* port;
+	char* user;
+	char* pass;
+	
+	uint8_t login;
+	int64_t session;
+
+	int fd;
+	maweb_state state;
+	size_t offset;
+	size_t allocated;
+	uint8_t* buffer;
+} maweb_instance_data;
diff --git a/backends/maweb.md b/backends/maweb.md
new file mode 100644
index 0000000..eb1ed44
--- /dev/null
+++ b/backends/maweb.md
@@ -0,0 +1,142 @@
+### The `maweb` backend
+
+This backend connects directly with the integrated *MA Web Remote* of MA Lighting consoles and OnPC
+instances (GrandMA2 / GrandMA2 OnPC / GrandMA Dot2 / GrandMA Dot2 OnPC).
+It grants read-write access to the console's playback faders and buttons as well as write access to
+the command line buttons.
+
+To allow this backend to connect to the console, enter the console configuration (`Setup` key),
+select `Console`/`Global Settings` and set the `Remotes` option to `Login enabled`.
+Create an additional user that is able to log into the Web Remote using `Setup`/`Console`/`User & Profiles Setup`.
+
+#### Global configuration
+
+The `maweb` backend does not take any global configuration.
+
+#### Instance configuration
+
+| Option        | Example value         | Default value         | Description							|
+|---------------|-----------------------|-----------------------|---------------------------------------------------------------|
+| `host`	| `10.23.42.21 80`     	| none                  | Host address (and optional port) of the MA Web Remote 	|
+| `user`	| `midimonster`		| none			| User for the remote session					|
+| `password`	| `midimonster`		| `midimonster`		| Password for the remote session				|
+
+#### Channel specification
+
+Currently, three types of channels can be assigned
+
+##### Executors
+
+Executors are arranged in pages, with each page having 90 fader executors and 90 button executors.
+Note that when creating a new show, only the first page is created and active.
+
+A fader executor consists of a fader, two buttons (`upper`, `lower`) above it and one `flash` button below it.
+
+These controls can be adressed like
+
+```
+mw1.page1.fader5 > mw1.page1.upper5
+mw1.page3.lower3 > mw1.page2.flash2
+```
+
+A button executor can likewise be mapped using the syntax
+
+```
+mw1.page2.button3 > mw1.page3.fader1
+```
+
+##### Command line buttons
+
+Command line buttons will be pressed when the incoming event value is greater than `0.9` and released when it is less than that.
+They can be mapped using the syntax
+
+```
+mw1.<button-name>
+```
+
+The following button names are recognized by the backend:
+
+* `SET`
+* `PREV`
+* `NEXT`
+* `CLEAR`
+* `FIXTURE_CHANNEL`
+* `FIXTURE_GROUP_PRESET`
+* `EXEC_CUE`
+* `STORE_UPDATE`
+* `OOPS`
+* `ESC`
+* `0`
+* `1`
+* `2`
+* `3`
+* `4`
+* `5`
+* `6`
+* `7`
+* `8`
+* `9`
+* `PUNKT`
+* `PLUS`
+* `MINUS`
+* `THRU`
+* `IF`
+* `AT`
+* `FULL`
+* `HIGH`
+* `ENTER`
+* `OFF`
+* `ON`
+* `ASSIGN`
+* `LABEL`
+* `COPY`
+* `TIME`
+* `PAGE`
+* `MACRO`
+* `DELETE`
+* `GOTO`
+* `GO_PLUS`
+* `GO_MINUS`
+* `PAUSE`
+* `SELECT`
+* `FIXTURE`
+* `SEQU`
+* `CUE`
+* `PRESET`
+* `EDIT`
+* `UPDATE`
+* `EXEC`
+* `STORE`
+* `GROUP`
+* `PROG_ONLY`
+* `SPECIAL_DIALOGUE`
+* `SOLO`
+* `ODD`
+* `EVEN`
+* `WINGS`
+* `RESET`
+* `MA`
+* `layerMode`
+* `featureSort`
+* `fixtureSort`
+* `channelSort`
+* `hideName`
+
+Note that each Web Remote connection has it's own command line, as such commands entered using this backend will not affect
+the command line on the main console. To do that, you will need to use another backend to feed input to the MA, such as
+the ArtNet or MIDI backends.
+
+#### Known bugs / problems
+
+To properly encode the user password, this backend depends on a library providing cryptographic functions (`libssl` / `openssl`).
+Since this may be a problem on some platforms, the backend can be built with this requirement disabled, which also disables the possibility
+to set arbitrary passwords. The backend will always try to log in with the default password `midimonster` in this case. The user name is still
+configurable.
+
+This backend is currently in active development. It therefore has some limitations:
+
+* It outputs a lot of debug information
+* It currently is write-only, channel events are only sent to the MA, not consumed by it
+* Fader executors (and their buttons) seem to work, I haven't tested button executors yet.
+* Command line events are sent, but I'm not sure they're being handled yet
+* I have so far only tested it with GradMA2 OnPC