15 files changed, 901 insertions, 0 deletions
diff --git a/shared/bin.c b/shared/bin.c
new file mode 100644
index 0000000..875d013
--- /dev/null
+++ b/shared/bin.c
@@ -0,0 +1,101 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "bin.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define CD_ENDIAN_LITTLE (1)
+#define CD_ENDIAN_BIG (0)
+
+#define _SHIFT_0B (8 * 0)
+#define _SHIFT_1B (8 * 1)
+#define _SHIFT_2B (8 * 2)
+#define _SHIFT_3B (8 * 3)
+#define _BYTE_0 ((uint32_t)0xff << (_SHIFT_0B))
+#define _BYTE_1 ((uint32_t)0xff << (_SHIFT_1B))
+#define _BYTE_2 ((uint32_t)0xff << (_SHIFT_2B))
+#define _BYTE_3 ((uint32_t)0xff << (_SHIFT_3B))
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wshift-count-overflow"
+cd_s_bin *cd_bin_from_uint8_t(uint8_t data) {
+	size_t size	  = 1;
+	cd_s_bin *ret = malloc(sizeof(cd_s_bin) + sizeof(uint8_t) * size);
+	ret->bytes	  = size;
+	ret->data[0]  = data;
+	return ret;
+}
+
+cd_s_bin *cd_bin_from_uint16_t(uint16_t data) {
+	size_t size	  = 2;
+	cd_s_bin *ret = malloc(sizeof(cd_s_bin) + sizeof(uint8_t) * size);
+	data		  = cd_bin_hton16(data);
+	ret->bytes	  = size;
+	ret->data[0]  = (data & _BYTE_1) >> _SHIFT_1B;
+	ret->data[1]  = (data & _BYTE_0) >> _SHIFT_0B;
+	return ret;
+}
+
+cd_s_bin *cd_bin_from_uint32_t(uint32_t data) {
+	size_t size	  = 4;
+	cd_s_bin *ret = malloc(sizeof(cd_s_bin) + sizeof(uint8_t) * size);
+	data		  = cd_bin_hton32(data);
+	ret->bytes	  = size;
+	ret->data[0]  = (data & _BYTE_3) >> _SHIFT_3B;
+	ret->data[1]  = (data & _BYTE_2) >> _SHIFT_2B;
+	ret->data[2]  = (data & _BYTE_1) >> _SHIFT_1B;
+	ret->data[3]  = (data & _BYTE_0) >> _SHIFT_0B;
+	return ret;
+}
+
+uint32_t cd_bin_hton32(uint32_t h32) {
+	if (g_cd_endianness == CD_ENDIAN_BIG) return h32;
+	return ((h32 & _BYTE_0) << _SHIFT_3B) | ((h32 & _BYTE_1) << _SHIFT_1B) |
+		   ((h32 & _BYTE_2) >> _SHIFT_1B) | ((h32 & _BYTE_3) >> _SHIFT_3B);
+}
+#pragma GCC diagnostic pop
+
+uint16_t cd_bin_hton16(uint16_t h16) {
+	if (g_cd_endianness == CD_ENDIAN_BIG) return h16;
+	return ((h16 & _BYTE_0) << _SHIFT_1B) | ((h16 & _BYTE_1) >> _SHIFT_1B);
+}
+
+uint32_t cd_bin_ntoh32(uint32_t n32) { return cd_bin_hton32(n32); }
+uint16_t cd_bin_ntoh16(uint16_t n16) { return cd_bin_hton16(n16); }
+uint32_t cd_bin_ntohd(uint8_t* n, size_t s) { return cd_bin_htond(n, s); }
+
+uint32_t cd_bin_htond(uint8_t* h, size_t s) {
+	if (s == sizeof(uint8_t)) return *h;
+	else if (s == sizeof(uint16_t)) return cd_bin_hton16(*(uint16_t*) h);
+	else if (s == sizeof(uint32_t)) return cd_bin_hton32(*(uint32_t*) h);
+	else return 0;
+}
+
+cd_s_bin *cd_bin_s_alloc(uint16_t bytes, uint8_t *data) {
+	cd_s_bin *temp = malloc(sizeof(cd_s_bin) + sizeof(uint8_t) * bytes);
+	temp->bytes	   = bytes;
+	memcpy(&temp->data, data, bytes);
+	return temp;
+}
+
+cd_s_bin *cd_bin_s_cat(cd_s_bin *a, cd_s_bin *b) {
+	uint8_t data[a->bytes + b->bytes];
+	memcpy(data, a->data, a->bytes);
+	memcpy(data + a->bytes, b->data, b->bytes);
+	cd_s_bin *c = cd_bin_s_alloc(a->bytes + b->bytes, data);
+	free(a);
+	free(b);
+	return c;
+}
+
+void cd_bin_repl_hton32(uint32_t *h32) { *h32 = cd_bin_hton32(*h32); }
+void cd_bin_repl_hton16(uint16_t *h16) { *h16 = cd_bin_hton16(*h16); }
+void cd_bin_repl_ntoh32(uint32_t *h32) { *h32 = cd_bin_ntoh32(*h32); }
+void cd_bin_repl_ntoh16(uint16_t *h16) { *h16 = cd_bin_ntoh16(*h16); }
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/shared/bin.h b/shared/bin.h
new file mode 100644
index 0000000..7506655
--- /dev/null
+++ b/shared/bin.h
@@ -0,0 +1,81 @@
+#pragma once
+
+/** @file bin.h */
+
+/**
+ * helper file for binary data
+ *
+ * - fix endianness with functions inspired by UNIX arpa/inet.h
+ * - convert uint16_t and uint32_t to cd_s_bin
+ */
+
+#include <stdint.h>
+#include <malloc.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern uint8_t g_cd_endianness;
+
+/** @brief cast `in.data` to `type out` */
+#define CD_CAST_BIN(type, in, out) type *out = (type *)&in->data;
+#define CD_CREATE_MSG_BIN(type, normal, bin) CD_CREATE_MSG_SIZE_BIN(type, sizeof(type), normal, bin)
+/** @brief  */
+#define CD_CREATE_MSG_SIZE_BIN(type, size, normal, bin)                                            \
+	cd_s_bin *bin = malloc(sizeof(cd_s_bin) + size);                                               \
+	bin->bytes	  = size;                                                                          \
+	type *normal  = (type *)&bin->data;
+
+/** @brief hold binary data with fixed size */
+typedef struct {
+	uint16_t bytes; /** @brief data size */
+	uint8_t data[]; /** @brief data */
+} cd_s_bin;
+
+/** @brief allocate new cd_s_bin struct and fill with `*data` for `bytes` bytes */
+cd_s_bin *cd_bin_s_alloc(uint16_t bytes, uint8_t *data);
+/** @brief concatenate 2 cd_s_bin structs, deallocates `a` and `b` */
+cd_s_bin *cd_bin_s_cat(cd_s_bin *a, cd_s_bin *b);
+
+cd_s_bin *cd_bin_from_uint8_t(uint8_t data);
+cd_s_bin *cd_bin_from_uint16_t(uint16_t data);
+cd_s_bin *cd_bin_from_uint32_t(uint32_t data);
+
+/** @brief convert 32-bit value from host endian to network (big-endian) */
+uint32_t cd_bin_hton32(uint32_t h32);
+/** @brief convert 16-bit value from host endian to network (big-endian) */
+uint16_t cd_bin_hton16(uint16_t h16);
+/** @brief convert 32-bit value from network (big-endian) to host endian */
+uint32_t cd_bin_ntoh32(uint32_t n32);
+/** @brief convert 16-bit value from network (big-endian) to host endian */
+uint16_t cd_bin_ntoh16(uint16_t n16);
+
+/**
+ * @brief convert (8*s)-bit value from network (big-endian) to host endian
+ * (dynamic size)
+ *
+ * @param n  pointer to number
+ * @param s  size of number in bytes
+ * 
+ * @return 32-bit integer regardless of `s`
+ *
+ * this function is exclusively used by the CD_DYN_MEMBER_SIZEOF macro in
+ * shared/protocol.c
+ */
+uint32_t cd_bin_ntohd(uint8_t* n, size_t s);
+uint32_t cd_bin_htond(uint8_t* h, size_t s);
+
+/** @brief replace 32-bit value from host endian to network (big-endian) */
+void cd_bin_repl_hton32(uint32_t *h32);
+/** @brief replace 16-bit value from host endian to network (big-endian) */
+void cd_bin_repl_hton16(uint16_t *h16);
+/** @brief replace 32-bit value from network (big-endian) to host endian */
+void cd_bin_repl_ntoh32(uint32_t *n32);
+/** @brief replace 16-bit value from network (big-endian) to host endian */
+void cd_bin_repl_ntoh16(uint16_t *n16);
+
+#ifdef __cplusplus
+}
+#endif
+
diff --git a/shared/consts.h b/shared/consts.h
index 6f70f09..57426bf 100644
--- a/shared/consts.h
+++ b/shared/consts.h
@@ -1 +1,11 @@
 #pragma once
+
+/** @file consts.h */
+
+/** @brief size of input (receive) buffer (in bytes) */
+#define CD_SERIAL_READ_BUFFER_SIZE 255
+/** @brief size of the error handling buffer (in errors, not bytes) */
+#define CD_ERROR_BUFFER_SIZE 16
+/** @brief size of the serial communication buffer (in messages, not bytes) */
+#define CD_SERCOMM_BUFFER_SIZE 16
+
diff --git a/shared/pclient.c b/shared/pclient.c
new file mode 100644
index 0000000..1b8e4e5
--- /dev/null
+++ b/shared/pclient.c
@@ -0,0 +1,164 @@
+#include <memory.h>
+
+#include "protocol.h"
+#include "pclient.h"
+#include "bin.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+cd_s_bin* cd_cmd_gen_ping() {
+	CD_CREATE_MSG_BIN(cd_s_cmd_ping, msg, bin);
+
+	msg->opcode = CD_CMD_PING;
+	msg->id = cd_bin_hton16(cd_protocol_fresh_message_id());
+
+	return bin;
+}
+
+cd_s_bin* cd_cmd_gen_get_node(bool all, cd_uuid_t uuid) {
+	CD_CREATE_MSG_BIN(cd_s_cmd_get_node, msg, bin);
+
+	msg->opcode = CD_CMD_GET_NODE;
+	msg->id = cd_bin_hton16(cd_protocol_fresh_message_id());
+	msg->all = all;
+	if (uuid != NULL) memcpy(msg->uuid, uuid, sizeof(cd_uuid_t));
+	else memset(msg->uuid, 0, sizeof(cd_uuid_t));
+
+	return bin;
+}
+
+cd_s_bin* cd_cmd_gen_post_led(bool on, cd_uuid_t uuid) {
+	CD_CREATE_MSG_BIN(cd_s_cmd_post_led, msg, bin);
+
+	msg->opcode = CD_CMD_POST_LED;
+	msg->id = cd_bin_hton16(cd_protocol_fresh_message_id());
+	msg->on = on;
+	memcpy(msg->uuid, uuid, sizeof(cd_uuid_t));
+
+	return bin;
+}
+
+cd_s_bin* cd_cmd_gen_post_link_add(cd_uuid_t button, cd_uuid_t light, cd_e_cmd_link_type type) {
+	CD_CREATE_MSG_BIN(cd_s_cmd_post_link, msg, bin);
+
+	msg->opcode = CD_CMD_POST_LINK;
+	msg->id = cd_bin_hton16(cd_protocol_fresh_message_id());
+	msg->add = true;
+	memcpy(msg->button, button, sizeof(cd_uuid_t));
+	memcpy(msg->led, light, sizeof(cd_uuid_t));
+	msg->type = type;
+
+	return bin;
+}
+
+cd_s_bin* cd_cmd_gen_post_link_rm(cd_uuid_t button, cd_uuid_t light) {
+	CD_CREATE_MSG_BIN(cd_s_cmd_post_link, msg, bin);
+
+	msg->opcode = CD_CMD_POST_LINK;
+	msg->id = cd_bin_hton16(cd_protocol_fresh_message_id());
+	msg->add = false;
+	memcpy(msg->button, button, sizeof(cd_uuid_t));
+	memcpy(msg->led, light, sizeof(cd_uuid_t));
+	msg->type = 0;
+
+	return bin;
+}
+
+cd_s_bin* cd_cmd_gen_post_net_add(cd_uuid_t uuid) {
+	CD_CREATE_MSG_BIN(cd_s_cmd_post_net, msg, bin);
+
+	msg->opcode = CD_CMD_POST_NET;
+	msg->id = cd_bin_hton16(cd_protocol_fresh_message_id());
+	msg->join = true;
+	memcpy(msg->uuid, uuid, sizeof(cd_uuid_t));
+
+	return bin;
+}
+
+cd_s_bin* cd_cmd_gen_post_net_rm(cd_uuid_t uuid) {
+	CD_CREATE_MSG_BIN(cd_s_cmd_post_net, msg, bin);
+
+	msg->opcode = CD_CMD_POST_NET;
+	msg->id = cd_bin_hton16(cd_protocol_fresh_message_id());
+	msg->join = false;
+	memcpy(msg->uuid, uuid, sizeof(cd_uuid_t));
+
+	return bin;
+}
+
+cd_s_bin* cd_cmd_res_status(cd_e_scmds cmd, cd_cmd_id_t id, bool error) {
+	CD_CREATE_MSG_BIN(cd_s_cmd_response, msg, bin);
+
+	msg->opcode = CD_CMD_RESPONSE;
+	msg->id = cd_bin_hton16(cd_protocol_fresh_message_id());
+	msg->response_type = cmd;
+	msg->response_id = id;
+	msg->error = error;
+	msg->response_size = 0;
+
+	return bin;
+}
+
+cd_s_bin* cd_cmd_res(cd_e_scmds cmd, cd_cmd_id_t id, uint16_t len, uint8_t* data) {
+	CD_CREATE_MSG_SIZE_BIN(cd_s_cmd_response, sizeof(cd_s_cmd_response) + len, msg, bin);
+
+	msg->opcode = CD_CMD_RESPONSE;
+	msg->id = cd_bin_hton16(cd_protocol_fresh_message_id());
+	msg->response_type = cmd;
+	msg->response_id = id;
+	msg->error = false;
+	msg->response_size = cd_bin_hton16(len);
+	memcpy(msg->response_info, data, len);
+
+	return bin;
+}
+
+cd_s_cmd_node* cd_cmd_node_alloc(const char* name, cd_s_cmd_node base, uint16_t link_count, cd_uuid_t* links) {
+	size_t name_len = strlen(name);
+	size_t links_size = sizeof(cd_uuid_t) * link_count;
+	size_t remaining_size = sizeof(char) * name_len + links_size;
+	cd_s_cmd_node* node = malloc(sizeof(cd_s_cmd_node) + remaining_size);
+	
+	memcpy(node->uuid, base.uuid, sizeof(cd_uuid_t));
+	memcpy(node->address, base.address, sizeof(cd_mac_addr_t));
+	node->name_len = name_len;
+	node->light_on = base.light_on;
+	node->provisioned = base.provisioned;
+	node->button_pub = cd_bin_hton32(base.button_pub);
+	node->link_count = cd_bin_hton16(link_count);
+	node->remaining_size = cd_bin_hton16(remaining_size);
+	void* cursor = (void*) &node->remaining_data[0];
+	memcpy(cursor, name, name_len); // copy name
+	cursor += name_len;
+	memcpy(cursor, links, links_size); // copy links
+
+	return node;
+}
+
+cd_s_cmd_response_get_node* cd_cmd_get_node_res_from_node_arr(uint16_t size, cd_s_cmd_node* arr[]) {
+	size_t remaining_size = 0;
+
+	for (unsigned int i = 0; i < size; i++) {
+		remaining_size += sizeof(cd_s_cmd_node) + cd_bin_ntoh16(arr[i]->remaining_size);
+	}
+
+	cd_s_cmd_response_get_node* response = malloc(sizeof(cd_s_cmd_response_get_node) + remaining_size);
+	response->node_count = cd_bin_hton16(size);
+	response->remaining_size = cd_bin_hton16(remaining_size);
+
+	void* cursor = response->nodes;
+	for (unsigned int i = 0; i < size; i++) {
+		size_t size = sizeof(cd_s_cmd_node) + cd_bin_ntoh16(arr[i]->remaining_size);
+		memcpy(cursor, arr[i], size);
+		cursor += size;
+	}
+
+	return response;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
diff --git a/shared/pclient.h b/shared/pclient.h
new file mode 100644
index 0000000..03a8a25
--- /dev/null
+++ b/shared/pclient.h
@@ -0,0 +1,91 @@
+#pragma once
+
+/** @file pclient.h */
+
+#include <stdbool.h>
+
+#include "protocol.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** @brief send data over platform standard serial out (doesn't free `data`) */
+void cd_pclient_send(cd_s_bin* data);
+
+/** @brief generate PING command */
+cd_s_bin* cd_cmd_gen_ping();
+/**
+ * @brief generate GET_NODE command
+ * @param all  get all nodes
+ * @param uuid  get specific node by uuid
+ */
+cd_s_bin* cd_cmd_gen_get_node(bool all, cd_uuid_t uuid);
+/**
+ * @brief generate POST_LED command
+ * @param on  light status
+ * @param uuid  node to set light of
+ */
+cd_s_bin* cd_cmd_gen_post_led(bool on, cd_uuid_t uuid);
+/**
+ * @brief generate POST_LINK command to add or update link
+ * @param button  button node uuid
+ * @param light  light node uuid
+ * @param type  type of link to set
+ */
+cd_s_bin* cd_cmd_gen_post_link_add(cd_uuid_t button, cd_uuid_t light, cd_e_cmd_link_type type);
+/**
+ * @brief generate POST_LINK command to remove link
+ * @param button  button node uuid
+ * @param light  light node uuid
+ */
+cd_s_bin* cd_cmd_gen_post_link_rm(cd_uuid_t button, cd_uuid_t light);
+/**
+ * @brief generate POST_NET command to provision node into network
+ * @param uuid  node uuid
+ */
+cd_s_bin* cd_cmd_gen_post_net_add(cd_uuid_t uuid);
+/**
+ * @brief generate POST_NET command to provision node out of network
+ * @param uuid  node uuid
+ */
+cd_s_bin* cd_cmd_gen_post_net_rm(cd_uuid_t uuid);
+
+/**
+ * @brief generate generic RESPONSE command with error field and no response_info
+ * @param cmd  original command opcode
+ * @param id  original command id
+ * @param error  `true` if some error occurred
+ */
+cd_s_bin* cd_cmd_res_status(cd_e_scmds cmd, cd_cmd_id_t id, bool error);
+/**
+ * @brief generate RESPONSE command with response_info
+ * @param cmd  original command opcode
+ * @param id  original command id
+ * @param len  size of `data` in bytes
+ * @param data  pointer to data
+ */
+cd_s_bin* cd_cmd_res(cd_e_scmds cmd, cd_cmd_id_t id, uint16_t len, uint8_t* data);
+/**
+ * @brief generate cd_s_cmd_response_get_node struct from array of cd_s_cmd_node pointers
+ * @param size  length of array
+ * @param arr  array of pointer to cd_s_cmd_node
+ */
+cd_s_cmd_response_get_node* cd_cmd_get_node_res_from_node_arr(uint16_t size, cd_s_cmd_node* arr[]);
+/**
+ * @brief allocate and fill cd_s_cmd_node struct
+ *
+ * @param base  base struct with values that can be initialized using an initialization list
+ * @param name  node name (length is calculated at runtime using strlen())
+ * @param link_count  amount of lights this node controls
+ * @param links  array of light node uuids
+ */
+cd_s_cmd_node* cd_cmd_node_alloc(const char* name, cd_s_cmd_node base, uint16_t link_count, cd_uuid_t* links);
+
+#define cd_remaining_sizeof(type, input_struct) ((sizeof(type) + cd_bin_ntoh16(input_struct->remaining_size)) /* NOLINT */)
+#define cd_cmd_node_sizeof(node) (cd_remaining_sizeof(cd_s_cmd_node, node) /* NOLINT */)
+#define cd_cmd_response_get_node_sizeof(res) (cd_remaining_sizeof(cd_s_cmd_response_get_node, res) /* NOLINT */)
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/shared/protocol-tests/.gitignore b/shared/protocol-tests/.gitignore
new file mode 100644
index 0000000..a8a0dce
--- /dev/null
+++ b/shared/protocol-tests/.gitignore
@@ -0,0 +1 @@
+*.bin
diff --git a/shared/protocol-tests/get-node-response.src b/shared/protocol-tests/get-node-response.src
new file mode 100644
index 0000000..31bf1ff
--- /dev/null
+++ b/shared/protocol-tests/get-node-response.src
@@ -0,0 +1,81 @@
+00: ff ; start byte
+01: 05 ; opcode (0x05 = response)
+02: 00 ; message id (0x0000)
+03: 00 ; ^
+04: 00 ; error byte (0x00 = false)
+05: 01 ; response type (0x01 = get node)
+06: 8f ; original message id (0x8ff8)
+07: f8 ; ^
+08: 00 ; remaining response size (0x39 = 57 bytes)
+09: 39 ; ^
+-------; |- remaining response (cd_s_cmd_response_get_node)
+0a: 00 ; | node count (0x0001 = 1)
+0b: 01 ; | ^
+0c: 00 ; | remaining response size (0x35 = 53 bytes)
+0d: 35 ; | ^
+-------; | |- remaining response (cd_s_cmd_node[1])
+0e: ff ; | | [esc]
+0f: ff ; | | uuid (ffffffff-0000-0000-dead-beef00000000)
+10: ff ; | | [esc]
+11: ff ; | | ^
+12: ff ; | | [esc]
+13: ff ; | | ^
+14: ff ; | | [esc]
+15: ff ; | | ^
+16: 00 ; | | ^
+17: 00 ; | | ^
+18: 00 ; | | ^
+19: 00 ; | | ^
+1a: de ; | | ^
+1b: ad ; | | ^
+1c: be ; | | ^
+1d: ef ; | | ^
+1e: 00 ; | | ^
+1f: 00 ; | | ^
+20: 00 ; | | ^
+21: 00 ; | | ^
+22: ff ; | | [esc]
+23: ff ; | | mac address (ff:00:ff:00:ff:00)
+24: 00 ; | | ^
+25: ff ; | | [esc]
+26: ff ; | | ^
+27: 00 ; | | ^
+28: ff ; | | [esc]
+29: ff ; | | ^
+2a: 00 ; | | ^
+2b: 04 ; | | name length (0x04 = 4)
+2c: 00 ; | | light on (0x00 = false)
+2d: 00 ; | | provisioned (0x00 = false)
+2e: de ; | | button publish address (0xdeadbeef)
+2f: ad ; | | ^
+30: be ; | | ^
+31: ef ; | | ^
+32: 00 ; | | link count (0x0001 = 1)
+33: 01 ; | | ^
+34: 00 ; | | remaining size (0x14 = 20 bytes)
+35: 14 ; | | ^
+-------; | | |- remaining response (char[4], cd_uuid_t[1])
+36: 67 ; | | | node name ("gert")
+37: 65 ; | | | ^
+38: 72 ; | | | ^
+39: 74 ; | | | ^
+3a: ff ; | | | [esc]
+3b: ff ; | | | link[0] uuid (ffffffff-0000-0000-dead-beef00000000)
+3c: ff ; | | | [esc]
+3d: ff ; | | | ^
+3e: ff ; | | | [esc]
+3f: ff ; | | | ^
+40: ff ; | | | [esc]
+41: ff ; | | | ^
+42: 00 ; | | | ^
+43: 00 ; | | | ^
+44: 00 ; | | | ^
+45: 00 ; | | | ^
+46: de ; | | | ^
+47: ad ; | | | ^
+48: be ; | | | ^
+49: ef ; | | | ^
+4a: 00 ; | | | ^
+4b: 00 ; | | | ^
+4c: 00 ; | | | ^
+4d: 00 ; | | | ^
diff --git a/shared/protocol-tests/makefile b/shared/protocol-tests/makefile
new file mode 100644
index 0000000..f8ac490
--- /dev/null
+++ b/shared/protocol-tests/makefile
@@ -0,0 +1,15 @@
+XXD := xxd
+RM := rm -f
+
+SRCS := $(wildcard *.src)
+TARGET := $(SRCS:.src=.bin)
+
+.PHONY: all clean
+
+all: $(TARGET)
+
+%.bin: %.src
+	$(XXD) -r -c1 $< $@
+
+clean:
+	$(RM) $(TARGET)
diff --git a/shared/protocol-tests/ping-response.src b/shared/protocol-tests/ping-response.src
new file mode 100644
index 0000000..57418d5
--- /dev/null
+++ b/shared/protocol-tests/ping-response.src
@@ -0,0 +1,10 @@
+00: ff ; start byte
+01: 05 ; response opcode
+02: 00 ; message id (0x0001)
+03: 01 ; ^
+04: 01 ; error (true)
+05: 00 ; response type (0x00 = ping)
+06: 00 ; original message id (0x0000)
+07: 00 ; ^
+08: 00 ; remainder size (0x0000)
+09: 00 ; ^
diff --git a/shared/protocol-tests/ping.src b/shared/protocol-tests/ping.src
new file mode 100644
index 0000000..beec10a
--- /dev/null
+++ b/shared/protocol-tests/ping.src
@@ -0,0 +1,4 @@
+00: ff ; start byte
+01: 00 ; ping opcode
+02: f8 ; message id (used as ping identifier)
+03: 8f ; ^
diff --git a/shared/protocol.c b/shared/protocol.c
new file mode 100644
index 0000000..fcc0f41
--- /dev/null
+++ b/shared/protocol.c
@@ -0,0 +1,58 @@
+#include <stddef.h>
+
+#include "protocol.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+cd_cmd_id_t  g_cd_protocol_fresh_message_id = 0;
+
+size_t cd_cmd_sizeof(uint8_t data[CD_SERIAL_READ_BUFFER_SIZE], uint8_t data_length) {
+	cd_cmd_opcode_t opcode = data[0];
+	if (CD_CMD_HANDLERS_SIZE[opcode] > 0) return CD_CMD_HANDLERS_SIZE[opcode];
+
+	cd_s_bin *copy = cd_bin_s_alloc(data_length, data);
+	size_t length = (*CD_CMD_HANDLERS_SIZEOF[opcode])(copy);
+
+	free(copy);
+
+	return length;
+}
+
+/**
+ * @brief macro to calculate size of message based on struct with member to
+ * indicate length of dynamic (last) field
+ *
+ * @param data  cd_s_bin pointer to currently received data
+ * @param struct_t  message struct
+ * @param length_field  struct field with dynamic length
+ *
+ * @return size_t with calculated size
+ *
+ * equivalent c code:
+ *
+ * size_t size = sizeof(struct_t);
+ * size_t dyn_member_offset = offsetof(struct_t, length_field);
+ * size_t dyn_member_size = sizeof(((struct_t*)0)->length_field);
+ * if (data->bytes >= (dyn_member_offset + dyn_member_size))
+ *     size += cd_bin_ntohd(&data->data[dyn_member_offset], dyn_member_size);
+ * return size;
+ */
+#define CD_DYN_MEMBER_SIZEOF(data, struct_t, length_field) \
+	sizeof(struct_t) + ( \
+	(data->bytes >= (offsetof(struct_t, length_field) + sizeof(((struct_t*)0)->length_field))) ? \
+		(cd_bin_ntohd(&data->data[offsetof(struct_t, length_field)], sizeof(((struct_t*)0)->length_field))) :\
+		0);
+
+size_t cd_cmd_response_sizeof(cd_s_bin* data) {
+	return CD_DYN_MEMBER_SIZEOF(data, cd_s_cmd_response, response_size);
+}
+
+cd_cmd_id_t cd_protocol_fresh_message_id() {
+	return g_cd_protocol_fresh_message_id++;
+}
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/shared/protocol.h b/shared/protocol.h
new file mode 100644
index 0000000..b9a2c93
--- /dev/null
+++ b/shared/protocol.h
@@ -0,0 +1,183 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** @file protocol.h */
+
+#define CD_SERIAL_START_BYTE 0xff
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "bin.h"
+#include "consts.h"
+
+/** @brief mac address (00:11:22:33:44:55) */
+typedef uint8_t cd_mac_addr_t[6];
+/** @brief uuid (ffeeddcc-bbaa-9988-7766-554433221100) */
+typedef uint8_t cd_uuid_t[16];
+
+/** @brief pub/sub address type */
+typedef uint32_t cd_mesh_psub_addr;
+
+/** @brief command opcode (identifies message type) */
+typedef uint8_t cd_cmd_opcode_t;
+/** @brief command id (identifies messages uniquely) */
+typedef uint16_t cd_cmd_id_t;
+/** @brief smallest boolean type */
+typedef uint8_t cd_cmd_bool_t;
+
+/** @brief cmd handler function signature */
+typedef void (cd_cmd_handler_t)(cd_s_bin *data);
+
+/** @brief used for numbering messages */
+extern cd_cmd_id_t g_cd_protocol_fresh_message_id;
+
+/** @brief get new message id */
+cd_cmd_id_t cd_protocol_fresh_message_id();
+
+#pragma pack(push, 1)
+
+typedef struct {
+	cd_cmd_opcode_t opcode; /** @brief cmd opcode */
+	cd_cmd_id_t id; /** @brief message id */
+} cd_s_cmd_ping;
+
+typedef struct {
+	cd_cmd_opcode_t opcode; /** @brief cmd opcode */
+	cd_cmd_id_t id; /** @brief message id */
+	cd_cmd_bool_t all; /** @brief get all known nodes */
+	cd_uuid_t uuid; /** @brief node uuid to get details from, ignored if `all` = `true` */
+} cd_s_cmd_get_node;
+
+typedef struct {
+	cd_cmd_opcode_t opcode; /** @brief cmd opcode */
+	cd_cmd_id_t id; /** @brief message id */
+	cd_cmd_bool_t on; /** @brief new led status */
+	cd_uuid_t uuid; /** @brief node uuid to set */
+} cd_s_cmd_post_led;
+
+typedef enum {
+	CD_CMD_LINK_TYPE_TOGGLE = 0x00, /** @brief button toggles light */
+	CD_CMD_LINK_TYPE_TURN_ON = 0x01, /** @brief button always turns on light (regardless of previous state) */
+	CD_CMD_LINK_TYPE_TURN_OFF = 0x02, /** @brief button always turns off light (regardless of previous state) */
+} cd_e_cmd_link_type;
+
+typedef struct {
+	cd_cmd_opcode_t opcode; /** @brief cmd opcode */
+	cd_cmd_id_t id; /** @brief message id */
+	cd_uuid_t button; /** @brief uuid of button node */
+	cd_uuid_t led; /** @brief uuid of led node */
+	cd_cmd_bool_t add; /** @brief `true` to create/overwrite link, `false` to remove link */
+	uint8_t type; /** @brief link type cd_e_cmd_link_type */
+} cd_s_cmd_post_link;
+
+typedef struct {
+	cd_cmd_opcode_t opcode; /** @brief cmd opcode */
+	cd_cmd_id_t id; /** @brief message id */
+	cd_uuid_t uuid; /** @brief node uuid */
+	cd_cmd_bool_t join; /** @brief `true` to join network, `false` to leave network */
+} cd_s_cmd_post_net;
+
+/** @brief protocol node */
+typedef struct {
+	cd_uuid_t uuid;		   /** @brief node network uuid */
+	cd_mac_addr_t address; /** @brief node bluetooth mac address */
+	uint8_t name_len;	   /** @brief name length in bytes */
+	cd_cmd_bool_t light_on;		   /** @brief state of light on node */
+	cd_cmd_bool_t provisioned;	   /** @brief whether the node is provisioned into the network */
+	cd_mesh_psub_addr button_pub; /** @brief button publish address */
+	uint16_t link_count; /** @brief amount of addresses to publish button press to */
+	uint16_t remaining_size; /** @brief calculated size of remaining_data for convenience */
+	const uint8_t remaining_data[]; /**
+									 * @brief remaining data (name and link array)
+									 *
+									 * this data is stored adjacently in memory
+									 * and is cast when reading/writing this
+									 * struct
+									 * 
+									 * 1. char[] name
+									 * 2. cd_uuid_t[] light_publish_addresses;
+									 */
+} cd_s_cmd_node;
+
+typedef struct {
+	uint16_t node_count; /** amount of nodes in nodes[] */
+	uint16_t remaining_size; /** remaining size (for convenience) */
+	cd_s_cmd_node nodes[]; /** nodes adjacent in memory (should be accessed using pointer arithmetic) */
+} cd_s_cmd_response_get_node;
+
+typedef struct {
+	cd_cmd_opcode_t opcode; /** @brief cmd opcode */
+	cd_cmd_id_t id; /** @brief response message id */
+	cd_cmd_bool_t error; /** @brief `true` if some error occurred */
+	cd_cmd_opcode_t response_type; /** @brief response type, used to cast type of `response_info` */
+	cd_cmd_id_t response_id; /** @brief original message id */
+	uint16_t response_size; /** @brief size of remaining response */
+	uint8_t response_info[]; /** @brief (CAST) remaining response struct, not read if `response_size`=`0` */
+} cd_s_cmd_response;
+
+#pragma pack(pop)
+
+/** @brief global handler for complete messages */
+void cd_cmd_handle(uint8_t data[CD_SERIAL_READ_BUFFER_SIZE], uint8_t length);
+/** @brief calculate message length for any message */
+size_t cd_cmd_sizeof(uint8_t data[CD_SERIAL_READ_BUFFER_SIZE], uint8_t length);
+
+/** @brief calculate dynamic size of response message */
+size_t cd_cmd_response_sizeof(cd_s_bin* data);
+
+// down here is the garbage manual duplicate code section for constants
+
+#define CD_CMD_COUNT 6
+typedef enum {
+	CD_CMD_PING = 0x00, /** @brief send ping */
+	CD_CMD_GET_NODE = 0x01, /** @brief get node(s) */
+	CD_CMD_POST_LED = 0x02, /** @brief set led */
+	CD_CMD_POST_LINK = 0x03, /** @brief set/remove link */
+	CD_CMD_POST_NET = 0x04, /** @brief (un)register node with network */
+	CD_CMD_RESPONSE = 0x05, /** @brief response message */
+} cd_e_scmds;
+
+cd_cmd_handler_t cd_cmd_ping,
+				 cd_cmd_get_node,
+				 cd_cmd_post_led,
+				 cd_cmd_post_link,
+				 cd_cmd_post_net,
+				 cd_cmd_response;
+
+/** @brief constant message sizes, 0 for dynamic size */
+static const size_t CD_CMD_HANDLERS_SIZE[CD_CMD_COUNT] = {
+	[CD_CMD_PING] = sizeof(cd_s_cmd_ping),
+	[CD_CMD_GET_NODE] = sizeof(cd_s_cmd_get_node),
+	[CD_CMD_POST_LED] = sizeof(cd_s_cmd_post_led),
+	[CD_CMD_POST_LINK] = sizeof(cd_s_cmd_post_link),
+	[CD_CMD_POST_NET] = sizeof(cd_s_cmd_post_net),
+	[CD_CMD_RESPONSE] = 0,
+};
+
+/** @brief constant message sizes, 0 for dynamic size */
+static size_t (* const CD_CMD_HANDLERS_SIZEOF[CD_CMD_COUNT])(cd_s_bin*) = {
+	[CD_CMD_PING] = NULL,
+	[CD_CMD_GET_NODE] = NULL,
+	[CD_CMD_POST_LED] = NULL,
+	[CD_CMD_POST_LINK] = NULL,
+	[CD_CMD_POST_NET] = NULL,
+	[CD_CMD_RESPONSE] = &cd_cmd_response_sizeof,
+};
+
+/** @brief stores message handlers in array with opcode as index */
+static cd_cmd_handler_t* const CD_CMD_HANDLERS[CD_CMD_COUNT] = {
+	[CD_CMD_PING] = &cd_cmd_ping,
+	[CD_CMD_GET_NODE] = &cd_cmd_get_node,
+	[CD_CMD_POST_LED] = &cd_cmd_post_led,
+	[CD_CMD_POST_LINK] = &cd_cmd_post_link,
+	[CD_CMD_POST_NET] = &cd_cmd_post_net,
+	[CD_CMD_RESPONSE] = &cd_cmd_response,
+};
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/shared/protocol.md b/shared/protocol.md
new file mode 100644
index 0000000..c3c229f
--- /dev/null
+++ b/shared/protocol.md
@@ -0,0 +1,15 @@
+# protocol specs
+
+## commands
+
+each command consists of a start byte, opcode, and a payload. each opcode
+defines logic to handle payload length, so certain commands might expect a
+fixed-length payload, a variable-length payload, or none at all. the start byte
+is `0xff`, and because most data sent is in binary format, if the data contains
+an `0xff` byte, it will be escaped by replacing it with two `0xff` bytes. this
+is converted to a single `0xff` on the receiving end, so these duplicated bytes
+and the starting byte don't count towards message length.
+
+opcodes are picked sequentially, and are stored as enum constants inside
+shared/protocol.h for code readability.
+
diff --git a/shared/serial_parse.c b/shared/serial_parse.c
new file mode 100644
index 0000000..bfc374a
--- /dev/null
+++ b/shared/serial_parse.c
@@ -0,0 +1,61 @@
+#include <string.h>
+
+#include "consts.h"
+#include "serial_parse.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+bool cd_serial_parse(uint8_t byte) {
+	static uint8_t current_message[CD_SERIAL_READ_BUFFER_SIZE] = {0};
+	static uint8_t current_message_index					   = 0;
+	static uint8_t complete_message_length					   = 2;
+
+	static bool attentive = false;
+	static bool listening = false;
+
+	if (byte == CD_SERIAL_START_BYTE) {
+		attentive = !attentive;
+		if (attentive && listening) return CD_SERIAL_READ_SUCCESS;
+	} else if (attentive) {
+		attentive = false;
+		listening = !listening;
+		if (!listening) return CD_SERIAL_READ_FAILURE;
+	}
+
+	if (!listening) return CD_SERIAL_READ_SUCCESS;
+	current_message[current_message_index++] = byte;
+
+	complete_message_length = cd_cmd_sizeof(current_message, current_message_index);
+
+	if (current_message_index == complete_message_length) {
+		cd_cmd_handle(current_message, current_message_index);
+
+		memset(&current_message, 0, CD_SERIAL_READ_BUFFER_SIZE);
+		current_message_index	= 0;
+		complete_message_length = 1;
+		attentive				= false;
+		listening				= false;
+		return CD_SERIAL_READ_SUCCESS;
+	}
+
+	return CD_SERIAL_READ_SUCCESS;
+}
+
+void cd_cmd_handle(uint8_t data[CD_SERIAL_READ_BUFFER_SIZE], uint8_t data_length) {
+	cd_s_bin *copy				= cd_bin_s_alloc(data_length, data);
+
+	if (data[0] >= CD_CMD_COUNT) return;
+	cd_cmd_handler_t* handler = CD_CMD_HANDLERS[data[0]];
+
+	if (handler == NULL) return;
+	(*handler)(copy);
+
+	free(copy);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
diff --git a/shared/serial_parse.h b/shared/serial_parse.h
new file mode 100644
index 0000000..1e9c404
--- /dev/null
+++ b/shared/serial_parse.h
@@ -0,0 +1,26 @@
+#pragma once
+
+/** @file serial_parse.h */
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include "protocol.h"
+
+#define CD_SERIAL_READ_SUCCESS true
+#define CD_SERIAL_READ_FAILURE false
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * parse serial data byte by byte
+ * @return true if read success, false if read fails
+ */
+bool cd_serial_parse(uint8_t byte);
+
+#ifdef __cplusplus
+}
+#endif
+