19 files changed, 799 insertions, 69 deletions

diff --git a/client/.gitignore b/client/.gitignore
deleted file mode 100644
index ba2906d..0000000
--- a/client/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-main
diff --git a/client/CMakeLists.txt b/client/CMakeLists.txt
index bcef4c0..35a55b6 100644
--- a/client/CMakeLists.txt
+++ b/client/CMakeLists.txt
@@ -8,13 +8,18 @@ project(puzzlebox_client C CXX)
 
 include(../proto/include.cmake)
 
-add_executable(main
+add_executable(pbc
 	main.cpp
+	rl.cpp
+	sock.cpp
+	cmd.cpp
+	parse.cpp
 	)
 
-target_link_libraries(main
+target_link_libraries(pbc
 	puzbus
 	mpack
+	readline # this is such a common library that I did not bother adding it as a submodule
 	)
 
 
diff --git a/client/cmd.cpp b/client/cmd.cpp
new file mode 100644
index 0000000..1ec2cb8
--- /dev/null
+++ b/client/cmd.cpp
@@ -0,0 +1,63 @@
+#include <cstdio>
+#include <cstdlib>
+#include <string.h>
+
+#include "cmd.h"
+#include "sock.h"
+#include "parse.h"
+
+char* consume_token(char* input, const char* ifs) {
+	strtok(input, ifs);
+	return strtok(NULL, "\0");
+}
+
+void cmd_exit(char*) {
+	exit(EXIT_SUCCESS);
+}
+
+void cmd_test(char*) {
+	const char* data = "Hello world!";
+	i2c_send(0x39, data, strlen(data));
+}
+
+void cmd_help(char*) {
+	printf("List of available commands:\n");
+	for (size_t i = 0; i < cmds_length; i++) {
+		struct cmd cmd = cmds[i];
+		printf("  %-*s", 10, cmd.name);
+		if (cmd.info != NULL)
+			printf("  %s", cmd.info);
+		printf("\n");
+	}
+
+	printf(
+		"\n"
+		"You can also use the TAB key to autocomplete commands\n"
+	);
+}
+
+void cmd_send(char* addr_str) {
+	char* data_str = consume_token(addr_str, IFS);
+
+	char* end;
+	uint16_t addr = strtol(addr_str, &end, 0);
+	if (addr_str + strlen(addr_str) != end) {
+		printf("address format error\n");
+		return;
+	}
+
+	char* data;
+	size_t data_size;
+	int err = strtodata(data_str, &data, &data_size);
+	if (err <= 0) {
+		printf("data format error at index %d:\n%s\n%*s^\n",
+				-err, data_str, -err, "");
+		return;
+	}
+
+	// printf("(0x%02x) -> \"%.*s\"\n", addr, data_size, data);
+	i2c_send(addr, data, data_size);
+
+	free(data);
+}
+
diff --git a/client/cmd.h b/client/cmd.h
new file mode 100644
index 0000000..9d20328
--- /dev/null
+++ b/client/cmd.h
@@ -0,0 +1,60 @@
+#pragma once
+
+#include <stddef.h>
+
+typedef void cmd_fn_t(char *);
+
+struct cmd {
+	void (* handle)(char *);
+	const char* name;
+	const char* info;
+	// TODO: tab completion function?
+};
+
+cmd_fn_t cmd_exit;
+cmd_fn_t cmd_test;
+cmd_fn_t cmd_help;
+cmd_fn_t cmd_send;
+cmd_fn_t cmd_status;
+cmd_fn_t cmd_reset;
+cmd_fn_t cmd_ls;
+
+static const struct cmd cmds[] = {
+	{
+		.handle = cmd_exit,
+		.name = "exit",
+		.info = "exit pbc",
+	},
+	{
+		.handle = cmd_test,
+		.name = "test",
+		.info = "send a test puzbus message",
+	},
+	{
+		.handle = cmd_help,
+		.name = "help",
+		.info = "show this help",
+	},
+	{
+		.handle = cmd_send,
+		.name = "send",
+		.info = "[debug] send raw message",
+	},
+	// {
+	// 	.handle = cmd_status,
+	// 	.name = "status",
+	// 	.info = "show global puzzle box state (main controller state)",
+	// },
+	// {
+	// 	.handle = cmd_reset,
+	// 	.name = "reset",
+	// 	.info = "reset entire game state",
+	// },
+	// {
+	// 	.handle = cmd_ls,
+	// 	.name = "ls",
+	// 	.info = "list connected puzzle modules",
+	// },
+};
+static const size_t cmds_length = sizeof(cmds) / sizeof(cmds[0]);
+
diff --git a/client/examples/puzbus-hello-world.cpp b/client/examples/puzbus-hello-world.cpp
new file mode 100644
index 0000000..dcc965b
--- /dev/null
+++ b/client/examples/puzbus-hello-world.cpp
@@ -0,0 +1,67 @@
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <unistd.h>
+
+#include "puzbusv1.h"
+
+int send_message() {
+	const char* data = "Test message data!";
+	struct pb_msg output = {
+		.addr = 0x39,
+		.data = (char*) data,
+		.length = strlen(data),
+	};
+
+	char* packed;
+	size_t size;
+	if (!pb_write(&output, &packed, &size)) {
+		printf("error writing!\n");
+		return EXIT_FAILURE;
+	}
+
+	fwrite(packed, sizeof(packed[0]), size, stdout);
+	fflush(stdout);
+
+	return EXIT_SUCCESS;
+}
+
+int read_message() {
+	freopen(NULL, "rb", stdin); // allow binary on stdin
+	struct pb_msg input;
+	
+	char buf[4]; // extremely small buffer to test chunked message parsing
+	size_t bytes = 0;
+
+	while ((bytes = fread(buf, sizeof(buf[0]), sizeof(buf), stdin)) > 0) {
+		int ret = pb_read(&input, buf, bytes);
+
+		// header read error
+		if (ret < 0) {
+			printf("error reading!\n");
+			return EXIT_FAILURE;
+		}
+
+		// continue reading if more bytes needed...
+		if (ret > 0) continue;
+
+		// message read completely!
+		printf("address: 0x%02x\n", input.addr);
+		printf("data:    \"%.*s\"\n", input.length, input.data);
+		free(input.data);
+		return EXIT_SUCCESS;
+	}
+
+	// if we reach this point, data was read but it did not contain a complete
+	// message, and is thus considered a failure
+	return EXIT_FAILURE;
+}
+
+int main() {
+	if (!isatty(fileno(stdout))) return send_message();
+	if (!isatty(fileno(stdin))) return read_message();
+	
+	printf("please pipe some data in or out to use this program\n");
+	return EXIT_SUCCESS;
+}
+
diff --git a/client/main.cpp b/client/main.cpp
index 30d7045..5c26107 100644
--- a/client/main.cpp
+++ b/client/main.cpp
@@ -1,54 +1,38 @@
 #include <cstdio>
 #include <cstdlib>
-#include <cstring>
-#include <unistd.h>
-
-#include "puzbusv1.h"
-
-int send_message() {
-	const char* data = "Test message data!";
-	struct pb_msg output = {
-		.addr = 0x39,
-		.data = (char*) data,
-		.length = strlen(data),
-	};
-
-	char* packed;
-	size_t size;
-	if (!pb_write(&output, &packed, &size)) {
-		printf("error writing!\n");
-		return 1;
-	}
+#include <cstdint>
+#include <exception>
 
-	fwrite(packed, sizeof(packed[0]), size, stdout);
-	fflush(stdout);
+#include "rl.h"
+#include "sock.h"
 
-	return 0;
-}
+PBSocket* sock;
 
-int read_message() {
-	freopen(NULL, "rb", stdin); // allow binary on stdin
-	struct pb_msg input;
-	
-	char buf[8]; // extremely small buffer to test chunked message parsing
-	size_t bytes = 0;
-	while ((bytes = fread(buf, sizeof(buf[0]), sizeof(buf), stdin)) > 0) {
-		if (!pb_read(&input, buf, bytes)) continue;
-
-		printf("address: 0x%02x\n", input.addr);
-		printf("data:    \"%.*s\"\n", input.length, input.data);
-		free(input.data);
-		return 0;
+int main(int argc, char** argv) {
+	if (argc < 2) {
+		printf("usage: %s addr [port]\n", argv[0]);
+		return EXIT_FAILURE;
 	}
 
-	return 1;
-}
+	// parse arguments
+	char* addr = argv[1];
+	uint16_t port = 9191;
+	if (argc >= 3) port = atoi(argv[2]);
+
+	sock = new PBSocket(addr, port);
+	try {
+		// connect to TCP socket (automatically spawns thread)
+		sock->sock_connect();
+	} catch (const std::exception& e) {
+		printf("error: %s\n", e.what());
+		return EXIT_FAILURE;
+	}
+
+	// enter main CLI (using GNU readline for comfyness)
+	int ret = cli_main();
+
+	delete sock;
 
-int main() {
-	if (!isatty(fileno(stdout))) return send_message();
-	if (!isatty(fileno(stdin))) return read_message();
-	
-	printf("please pipe some data in or out to use this program\n");
-	return 0;
+	return ret;
 }
 
diff --git a/client/parse.cpp b/client/parse.cpp
new file mode 100644
index 0000000..223dc5d
--- /dev/null
+++ b/client/parse.cpp
@@ -0,0 +1,117 @@
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "parse.h"
+
+static int parse_str(const char* str, char* data, size_t* size) {
+	char closing = str[0];
+	char escape = false;
+	bool scan = data == NULL;
+	int i = 0;
+	size_t len = strlen(str);
+
+	switch (str[i]) {
+		case '\'':
+			escape = false;
+			break;
+		case '\"':
+			escape = true;
+			break;
+		default:
+			return -i;
+	}
+
+	for (i = 1; i < len && str[i] != '\0'; i++) {
+		char c = str[i];
+
+		if (c == closing) {
+			if (scan) printf("string%s of length %d\n", escape ? " (w/ escape)" : "", i - 1);
+			return i + 1; // +1 for closing quote
+		}
+
+		if (scan) *size += 1;
+	}
+
+	return -i;
+}
+
+static int parse_num(const char* str, char* data, size_t* size) {
+	const char* ifs = IFS;
+	size_t len = strcspn(str, ifs);
+	bool scan = data == NULL;
+	int i = 0;
+	int base = 10;
+	bool bytestring = false;
+
+	const char* colon = strchr(str, ':');
+	if (colon != NULL && colon < str + len) { // byte string
+		base = 16;
+		bytestring = true;
+	} else if (len > 2 && strncmp(str, "0x", 2) == 0) { // hexadecimal prefix
+		base = 16;
+		i += 2;
+	}/* else if (len > 1 && strncmp(str, "0", 1) == 0) { // octal prefix
+		base = 8;
+		i += 1;
+	}*/
+
+	const char* set;
+	// if (base == 8) set = SET_OCT;
+	if (base == 10) set = SET_DEC;
+	if (base == 16) {
+		if (bytestring) set = SET_HEX_STR;
+		else set = SET_HEX;
+	}
+	
+	size_t len_ok = strspn(str + i, set) + i;
+	if (len != len_ok) return -len_ok;
+
+	if (scan) {
+		if (base == 10) *size += 1;
+		else if (base == 16) {
+			if (!bytestring) {
+				*size += (len - i + 1) / 2;
+			} else {
+				for (; colon != NULL && colon < str + len; colon = strchr(str, ':')) {
+					*size += 1;
+				}
+			}
+		}
+	}
+
+	if (scan) printf("number (base %d%s) of length %lu\n", base, bytestring ? " as bytestring" : "", len - i);
+	return len;
+}
+
+int strtodata(const char* str, char** data, size_t* size) {
+	const char* ifs = IFS;
+	*size = 0;
+	size_t i;
+	size_t len = strlen(str);
+
+	for (i = 0; i < len;) {
+		// skip whitespace
+		int run;
+		run = strspn(&str[i], ifs);
+		if (run > 0) printf("skipping whitespace for %d bytes...\n", run);
+		i += run;
+		// end of string
+		if (str[i] == '\0') break;
+
+		if ((run = parse_str(str + i, NULL, size)) > 0) { i += run; continue; }
+		if ((run = parse_num(str + i, NULL, size)) > 0) { i += run; continue; }
+
+		// no format detected
+		return -i + run;
+	}
+	printf("end of string w/o parse errors\n");
+	printf("buffer size is now %lu\n", *size);
+	exit(0);
+
+	*data = (char*) malloc(*size);
+
+	return 0;
+}
+
diff --git a/client/parse.h b/client/parse.h
new file mode 100644
index 0000000..10274e7
--- /dev/null
+++ b/client/parse.h
@@ -0,0 +1,42 @@
+#pragma once
+
+#include <stddef.h>
+
+#define IFS " \t\n"
+
+#define SET_OCT "01234567"
+#define SET_DEC "0123456789"
+#define SET_HEX SET_DEC"abcdefABCDEF"
+#define SET_HEX_STR SET_HEX":"
+
+/**
+ * \brief modify \p token to point to the first token when broken up on \p ifs
+ * and return the remaining data
+ *
+ * \p token will be null-terminated to indicate the end of the first token. A
+ * pointer to the remaining line after the NULL byte is returned, or NULL when
+ * the end of the string has been reached.
+ *
+ * \param token  input string
+ * \param ifs    string containing field separators
+ *
+ * \return the remaining data after \p token and the first \p ifs
+ */
+char* consume_token(char* token, const char* ifs);
+
+/**
+ * \brief convert string with literals into raw data
+ *
+ * \param str   input string containing literals
+ * \param data  pointer to \c char* that will store the resulting data
+ * \param size  size of \p data
+ *
+ * \return 0 or a negative integer representing the index where there is a
+ * syntax error if there was an error, or a positive integer representing the
+ * amount of bytes parsed from \p str
+ *
+ * \note The pointer that \p data refers to will not be initialized by this
+ * function if parsing fails
+ */
+int strtodata(const char* str, char** data, size_t* size);
+
diff --git a/client/pbc b/client/pbc
new file mode 120000
index 0000000..51eda50
--- /dev/null
+++ b/client/pbc
@@ -0,0 +1 @@
+build/pbc
\ No newline at end of file
diff --git a/client/readme.md b/client/readme.md
new file mode 100644
index 0000000..04471d2
--- /dev/null
+++ b/client/readme.md
@@ -0,0 +1,21 @@
+# puzzle box client
+
+goal (in order of implementation):
+```
+(pbc) help
+    exit                exit pbc
+    test                send a test puzbus message
+    help                show this help
+    send <addr> <data>  [debug] send raw message
+    status              show global puzzle box state (main controller state)
+    reset               reset entire game state
+    ls                  list connected puzzle modules
+```
+
+
+```
+send 0x39 "Hello world!" de:ad:be:ef 0xff     5        0a       0750
+          ^~~~~~~~~~~~~~ ^~~~~~~~~~~ ~^~~     ~^       ~^       ~~~~^
+          STR_INTP       BYTE_ARR    UNSIGNED UNSIGNED UNSIGNED UNSIGNED
+                                     (hex+0x) (dec)    (hex)    (oct)
+```
diff --git a/client/rl.cpp b/client/rl.cpp
new file mode 100644
index 0000000..3f93e99
--- /dev/null
+++ b/client/rl.cpp
@@ -0,0 +1,86 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdarg.h>
+
+#include <readline/readline.h>
+#include <readline/history.h>
+
+#include "rl.h"
+#include "cmd.h"
+#include "parse.h"
+
+void rl_printf(const char *fmt, ...) {
+	// save line
+	char* saved_line = rl_copy_text(0, rl_end);
+	int saved_point = rl_point;
+	int saved_end = rl_end;
+
+	// clear line
+	rl_save_prompt();
+	rl_replace_line("", 0);
+	rl_redisplay();
+
+	// printf
+	va_list args;
+	va_start(args, fmt);
+	vprintf(fmt, args);
+	va_end(args);
+
+	// restore line
+	rl_restore_prompt();
+	rl_replace_line(saved_line, 0);
+	rl_point = saved_point;
+	rl_end = saved_end;
+	rl_redisplay();
+
+	free(saved_line);
+}
+
+static void cli_cmd(char* cmd) {
+	char* line = consume_token(cmd, IFS);
+
+	for (size_t i = 0; i < cmds_length; i++) {
+		if (strncmp(cmds[i].name, cmd, strlen(cmd)) != 0)
+			continue;
+
+		cmds[i].handle(line);
+		return;
+	}
+
+	printf("unknown command!\n");
+}
+
+static char* rl_completion_entries(const char *text, int state) {
+	static size_t i = 0;
+	if (state == 0) i = 0;
+
+	while (i < cmds_length) {
+		struct cmd cmd = cmds[i];
+		i++;
+		if (strncmp(text, cmd.name, strlen(text)) == 0) {
+			return strdup(cmd.name);
+		}
+	}
+
+	return NULL;
+}
+
+int cli_main() {
+	char* input = NULL;
+	rl_completion_entry_function = rl_completion_entries;
+
+	while (1) {
+		if (input != NULL) free(input);
+		input = readline(CLI_PROMPT);
+
+		if (input == NULL) return EXIT_SUCCESS; // exit on ^D (EOF)
+		if (*input == '\0') continue; // ignore empty lines
+		add_history(input);
+
+		cli_cmd(input);
+	}	
+
+	return EXIT_SUCCESS;
+}
+
diff --git a/client/rl.h b/client/rl.h
new file mode 100644
index 0000000..503225f
--- /dev/null
+++ b/client/rl.h
@@ -0,0 +1,10 @@
+#pragma once
+
+#define COLOR_OFF "\x1b[0m"
+#define COLOR_BOLD "\x1b[1m"
+
+#define CLI_PROMPT "(" COLOR_BOLD "pbc" COLOR_OFF ") "
+
+int cli_main();
+void rl_printf(const char *fmt, ...);
+
diff --git a/client/sock.cpp b/client/sock.cpp
new file mode 100644
index 0000000..f967f64
--- /dev/null
+++ b/client/sock.cpp
@@ -0,0 +1,125 @@
+#include <arpa/inet.h>
+#include <cstring>
+#include <stdexcept>
+#include <unistd.h>
+#include <cstdio>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <errno.h>
+
+#include <thread>
+
+#include "puzbusv1.h"
+#include "sock.h"
+#include "rl.h"
+
+using std::logic_error;
+using std::thread;
+
+PBSocket::PBSocket() { }
+PBSocket::PBSocket(const char * addr, uint16_t port) : PBSocket() {
+	set_server(addr, port);
+}
+
+PBSocket::~PBSocket() {
+	// stop TCP listen thread
+	if (_thread != nullptr) {
+		_thread->detach();
+		delete _thread;
+	}
+
+	sock_close();
+}
+
+void PBSocket::set_server(const char * addr, uint16_t port) {
+	_addr = addr;
+	_port = port;
+}
+
+void PBSocket::sock_connect() {
+	if (_addr == NULL) throw logic_error("no server address defined");
+	if (_port == 0) throw logic_error("no server port defined");
+
+	if (_thread != nullptr) throw logic_error("already connected");
+
+	rl_printf("connecting to %s on port %d...\n", _addr, _port);
+
+	_fd = socket(AF_INET, SOCK_STREAM, 0);
+	if (_fd < 0) throw logic_error("socket create failed");
+	
+	struct sockaddr_in server = {
+		.sin_family = AF_INET,
+		.sin_port = htons(_port),
+		.sin_addr = {
+			.s_addr = inet_addr(_addr),
+		},
+	};
+	int ret = connect(_fd, (struct sockaddr*) &server, sizeof(server));
+	if (ret != 0) throw logic_error(strerror(errno));
+
+	this->_thread = new thread(&PBSocket::sock_task, this);
+}
+
+void PBSocket::sock_close() {
+	if (_fd < 0) return; // already closed
+	close(_fd);
+	_fd = -1;
+}
+
+void PBSocket::send(const char * buf, size_t buf_sz) {
+	write(_fd, buf, buf_sz);
+}
+
+void PBSocket::sock_task() {
+	struct pb_msg input;
+
+	while(1) {
+		char buf[80];
+		ssize_t bytes = read(_fd, buf, sizeof(buf));
+
+		if (bytes == -1) {
+			rl_printf("error: %s (%d)\n", strerror(errno), errno);
+			break;
+		}
+
+		// skip empty frames
+		if (bytes == 0) continue;
+
+		int ret = pb_read(&input, buf, bytes);
+
+		// header read error
+		if (ret < 0) {
+			rl_printf("pb_read error!\n");
+			break;
+		}
+
+		// continue reading if more bytes needed...
+		if (ret > 0) continue;
+
+		// message read completely!
+		i2c_recv(input.addr, input.data, input.length);
+		free(input.data);
+	}
+
+	sock_close();
+}
+
+void i2c_send(uint16_t addr, const char * data, size_t data_size) {
+	struct pb_msg msg = {
+		.addr = addr,
+		.data = (char *) data,
+		.length = data_size,
+	};
+
+	char* packed;
+	size_t size;
+	if (!pb_write(&msg, &packed, &size)) return;
+
+	sock->send(packed, size);
+}
+
+void i2c_recv(uint16_t addr, const char * data, size_t data_size) {
+	rl_printf("[0x%02x]: %.*s\n", addr, data_size, data);
+}
+
diff --git a/client/sock.h b/client/sock.h
new file mode 100644
index 0000000..42eba3b
--- /dev/null
+++ b/client/sock.h
@@ -0,0 +1,34 @@
+#pragma once
+
+#include <cstdint>
+#include <thread>
+
+class PBSocket {
+public:
+	PBSocket();
+	PBSocket(const char * addr, uint16_t port);
+	virtual ~PBSocket();
+
+	void set_server(const char * addr, uint16_t port);
+
+	void sock_connect();
+
+	void send(const char * buf, size_t buf_sz);
+
+private:
+	void sock_task();
+	void sock_close();
+
+	std::thread* _thread = nullptr;
+
+	const char * _addr = NULL;
+	uint16_t _port = 0;
+
+	int _fd = -1;
+};
+
+extern PBSocket* sock;
+
+void i2c_send(uint16_t addr, const char * data, size_t data_size);
+void i2c_recv(uint16_t addr, const char * data, size_t data_size);
+
diff --git a/main/CMakeLists.txt b/main/CMakeLists.txt
index 88abf60..30685a4 100644
--- a/main/CMakeLists.txt
+++ b/main/CMakeLists.txt
@@ -33,6 +33,7 @@ target_link_libraries(main
 	hardware_i2c
 	FreeRTOS-Kernel
 	FreeRTOS-Kernel-Heap4
+	puzbus
 	mpack
 	)
 
diff --git a/main/sock.c b/main/sock.c
index dac62af..4f50981 100644
--- a/main/sock.c
+++ b/main/sock.c
@@ -3,19 +3,63 @@
 #include <lwip/opt.h>
 #include <lwip/sys.h>
 #include <lwip/api.h>
+#include <string.h>
 
 #include "init.h"
 #include "config.h"
+#include "puzbusv1.h"
+#include "sock.h"
 
 struct netconn* current_connection = NULL;
+struct pb_msg recv_msg;
+
+void i2c_send(uint16_t addr, const char * data, size_t data_size) {
+	if (current_connection == NULL) return;
+
+	struct pb_msg send_msg = {
+		.addr = addr,
+		.data = (char *) data,
+		.length = data_size,
+	};
+
+	char * buf;
+	size_t buf_sz;
+
+	if (!pb_write(&send_msg, &buf, &buf_sz)) return;
+
+	// NOTE: netconn does return an error code, but the data needs to be freed
+	// whether netconn throws an error or not, so it remains unused
+	netconn_write(current_connection, buf, buf_sz, NETCONN_COPY);
+
+	free(buf);
+}
+
+void i2c_recv(uint16_t addr, const char * data, size_t data_size) {
+	printf("address: 0x%02x\n", addr);
+	printf("data:    \"%.*s\"\n", data_size, data);
+
+	// send message back
+	char reply[] = "Test message back!";
+	i2c_send(0x69, reply, strlen(reply));
+
+	// TODO: this function should forward the recieved message onto the puzzle
+	// bus instead of printing/replying
+}
 
 void recv_handler(struct netconn* conn, struct netbuf* buf) {
-	void *data;
-	uint16_t len;
+	pb_read_reset(&recv_msg);
 
 	do {
-		netbuf_data(buf, &data, &len);
-		printf("got %d bytes!\n", len);
+		char* data;
+		uint16_t len;
+		netbuf_data(buf, (void**)&data, &len);
+
+		// continue early if more data is needed to complete message
+		if (!pb_read(&recv_msg, data, len)) continue;
+
+		// forward received message to puzzle bus
+		i2c_recv(recv_msg.addr, recv_msg.data, recv_msg.length);
+		free(recv_msg.data);
 	} while (netbuf_next(buf) >= 0);
 
 	netbuf_delete(buf);
diff --git a/main/sock.h b/main/sock.h
index 2a73418..f2db35d 100644
--- a/main/sock.h
+++ b/main/sock.h
@@ -6,6 +6,6 @@
 /** \brief start listening for TCP socket requests */
 void serve_task();
 
-void i2c_send(uint16_t addr, char* data, size_t data_size);
-void i2c_recv(uint16_t addr, char* data, size_t data_size);
+void i2c_send(uint16_t addr, const char * data, size_t data_size);
+void i2c_recv(uint16_t addr, const char * data, size_t data_size);
 
diff --git a/proto/puzbusv1.c b/proto/puzbusv1.c
index 3ff7c63..73deda5 100644
--- a/proto/puzbusv1.c
+++ b/proto/puzbusv1.c
@@ -1,25 +1,48 @@
 #include <mpack.h>
 #include <stdio.h>
 
+// MIN() macro
+#include <sys/param.h>
+// TODO: check if this works on pico as well
+
 #include "puzbusv1.h"
 
-int pb_read(struct pb_msg* target, char* buf, size_t buf_sz) {
+int pb_read(struct pb_msg * target, const char * buf, size_t buf_sz) {
+	// a new reader is used per buffer block passed to this function
 	mpack_reader_t reader;
-	printf("read %lu bytes...\n", buf_sz);
-
 	mpack_reader_init_data(&reader, buf, buf_sz);
 
-	uint16_t address = mpack_expect_u16(&reader);
-	char data_buf[80];
-	size_t data_size = mpack_expect_bin_buf(&reader, data_buf, sizeof(data_buf));
-
-	printf("0x%02x\n", address);
-	printf("\"%.*s\"\n", data_size, data_buf);
+	// at start of message
+	if (target->_rdata == 0) {
+		// NOTE: The entire start of a message needs to be readable from the buffer
+		// at this point. When target->addr can be read and target->length is past
+		// the end of the current buffer block, this function will crash and burn.
+		// This is a highly unlikely scenario, as pb_read is called for each chunk
+		// of a TCP frame, and frames (should) include only one puzzle bus message.
+		// The check here is kind of optional.
+		if (buf_sz < 4) return -1;
+
+		target->addr = mpack_expect_u16(&reader);
+		target->length = target->_rdata = mpack_expect_bin(&reader);
+		target->data = (char *) malloc(target->length);
+	}
+
+	// continue reading chunks of target->data until the amount of bytes
+	// specified in target->length
+	size_t to_read = MIN(mpack_reader_remaining(&reader, NULL), target->_rdata);
+	char * data = target->data + target->length - target->_rdata;
+	mpack_read_bytes(&reader, data, to_read);
+	target->_rdata -= to_read;
+
+	// if rdata = 0, the message was completely read
+	return target->_rdata;
+}
 
-	return 0;
+void pb_read_reset(struct pb_msg * target) {
+	target->_rdata = 0;
 }
 
-int pb_write(struct pb_msg* target, char** buf, size_t* buf_sz) {
+bool pb_write(const struct pb_msg * target, char ** buf, size_t * buf_sz) {
 	mpack_writer_t writer;
 	mpack_writer_init_growable(&writer, buf, buf_sz);
 
diff --git a/proto/puzbusv1.h b/proto/puzbusv1.h
index 116dbf9..0985b2b 100644
--- a/proto/puzbusv1.h
+++ b/proto/puzbusv1.h
@@ -7,14 +7,62 @@
 extern "C" {
 #endif
 
+/** \brief Puzzle bus message (v1) */
 struct pb_msg {
-	uint16_t addr;
-	char* data;
-	size_t length;
+	uint16_t addr; //!< I^2^C address
+	char * data;   //!< message content
+	size_t length; //!< message size
+	size_t _rdata; //!< \private remaining bytes to read until message is complete
 };
 
-int pb_read(struct pb_msg* target, char* buf, size_t buf_sz);
-int pb_write(struct pb_msg* target, char** buf, size_t* buf_sz);
+/**
+ * \brief Read chunk of input stream, and store resulting message in \p target
+ *
+ * This function is called for each chunk of data from an input stream, and
+ * will parse the next puzzle bus message into \p target. The input stream is
+ * assumed to only contain messages encoded by \p pb_write()
+ *
+ * \param target  pointer to struct that will contain the finished message data
+ * \param buf     pointer to input stream data chunk
+ * \param buf_sz  size of \p buf
+ *
+ * \returns Integer representing amount of bytes required to finish message, or
+ * -1 if the message header could not be read. If this function returns 0, the
+ *  message in \p target is complete.
+ *
+ * \note target->data will automatically be allocated by this function, even if
+ * the message is not fully parsed. This variable must be `free()`d by the
+ * caller after each complete message to prevent memory leaks.
+ */
+int pb_read(struct pb_msg * target, const char * buf, size_t buf_sz);
+
+/**
+ * \brief reset the remaining message data counter
+ *
+ * Calling this function has the effect of forcing \c pb_read() to parse the
+ * next buffer chunk as the start of a new message. This function may be called
+ * before reading a TCP frame's data to mitigate any synchronization issues
+ * arising from earlier corrupt or otherwise malformed messages.
+ */
+void pb_read_reset(struct pb_msg * target);
+
+/**
+ * \brief Allocate and write a msgpack-formatted message to \p buf
+ *
+ * This function allocates a buffer large enough to fit the message specified
+ * in \p target, and encodes the data in \p target in a format that can be
+ * decoded later using \p pb_read()
+ *
+ * \param target  pointer to struct that contains the message data
+ * \param buf     pointer to \c char* that will contain the formatted message
+ * \param buf_sz  pointer to \c size_t that will represent the final size of \p buf
+ *
+ * \returns boolean true if a the message could be encoded successfully, false
+ * if there was some kind of error
+ *
+ * \note the pointer stored in \p buf must be `free()`d by the caller afterwards
+ */
+bool pb_write(const struct pb_msg * target, char ** buf, size_t * buf_sz);
 
 #ifdef __cplusplus
 }