From 9a2efcce2eefe8ada0ae7a71d7b0bf6261d073b5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juhani=20Krekel=C3=A4?= <juhani@krekelä.fi>
Date: Sun, 4 Aug 2019 11:16:19 +0300
Subject: [PATCH] Start working on file sending

---
 ethermess-backend.c | 73 +++++++++++++++++++++++++++++----------------
 ethermess.py        |  9 +++++-
 2 files changed, 56 insertions(+), 26 deletions(-)

diff --git a/ethermess-backend.c b/ethermess-backend.c
index baba23b..1e40d5a 100644
--- a/ethermess-backend.c
+++ b/ethermess-backend.c
@@ -22,7 +22,7 @@
 #include <time.h>
 #include <unistd.h>
 
-#define EM_PROTOCOL_VERSION 0
+#define EM_PROTOCOL_VERSION 1
 #define EM_MESSAGE_MAX_LENGTH (1500 - 2 - 2 - 2)
 #define EM_STATUS_BROADCAST_TIME (60 * 1000 + 1000 * random_byte() / 64)
 #define EM_RETRANSMIT_TIME (1000 + random_byte() * 2)
@@ -37,6 +37,9 @@
 #define EMT_MESSAGE 5
 #define EMT_ACK 6
 
+// Version 1
+#define EMT_FILE_OFFER 7
+
 #define EMS_AVAILABLE 0
 #define EMS_UNAVAILABLE 1
 #define EMS_OFFLINE 2
@@ -395,6 +398,14 @@ void send_ack(const unsigned char destination[6], uint16_t msgid) {
 	send_frame(frame, sizeof(frame));
 }
 
+void send_file_offer(const unsigned char destination[6]) {
+	unsigned char frame[14 + 2];
+
+	write_headers(frame, destination, 1, EMT_FILE_OFFER);
+
+	send_frame(frame, sizeof(frame));
+}
+
 void readallx(int fd, unsigned char *buf, size_t length) {
 	size_t completed = 0;
 	while (completed < length) {
@@ -496,6 +507,10 @@ void read_command(void) {
 		send_status(broadcast_mac);
 	} else if (cmd == 'm') {
 		read_message();
+	} else if (cmd == 'f') {
+		unsigned char mac[6];
+		readallx(0, mac, sizeof(mac));
+		send_file_offer(mac);
 	} else {
 		errx(1, "Frontend sent an unknown command %c", cmd);
 	}
@@ -867,35 +882,43 @@ void process_frame(void) {
 	// Extract Ethermess packet type
 	unsigned char packet_type = frame[15];
 
-	// Process the packet based on the packet type
-	switch (packet_type) {
-		case EMT_STATUS_REQUEST:
-			if (check_padding(&frame[16], 0, packet_length - 16)) {
-				send_status(source_mac);
-			}
-			break;
+	// Process the packet based on the version and packet type
+	if (version == 0) {
+		switch (packet_type) {
+			case EMT_STATUS_REQUEST:
+				if (check_padding(&frame[16], 0, packet_length - 16)) {
+					send_status(source_mac);
+				}
+				break;
 
-		case EMT_STATUS:
-			handle_status(source_mac, &frame[16], packet_length - 16);
-			break;
+			case EMT_STATUS:
+				handle_status(source_mac, &frame[16], packet_length - 16);
+				break;
 
-		case EMT_MSGID_REQUEST:
-			if (check_padding(&frame[16], 0, packet_length - 16)) {
-				send_msgid(source_mac);
-			}
-			break;
+			case EMT_MSGID_REQUEST:
+				if (check_padding(&frame[16], 0, packet_length - 16)) {
+					send_msgid(source_mac);
+				}
+				break;
 
-		case EMT_MSGID:
-			handle_msgid(source_mac, &frame[16], packet_length - 16);
-			break;
+			case EMT_MSGID:
+				handle_msgid(source_mac, &frame[16], packet_length - 16);
+				break;
 
-		case EMT_MESSAGE:
-			handle_message(source_mac, &frame[16], packet_length - 16);
-			break;
+			case EMT_MESSAGE:
+				handle_message(source_mac, &frame[16], packet_length - 16);
+				break;
 
-		case EMT_ACK:
-			handle_ack(source_mac, &frame[16], packet_length - 16);
-			break;
+			case EMT_ACK:
+				handle_ack(source_mac, &frame[16], packet_length - 16);
+				break;
+		}
+	} else if (version == 1) {
+		switch (packet_type) {
+			case EMT_FILE_OFFER:
+				fprintf(stderr, "File offered\n"); //debg
+				break;
+		}
 	}
 }
 
diff --git a/ethermess.py b/ethermess.py
index 230b411..1be7832 100644
--- a/ethermess.py
+++ b/ethermess.py
@@ -208,6 +208,9 @@ def set_status_nick(backend, status, nick):
 	encoded = nick.encode('utf-8')
 	writeall(backend, b's' + bytes([status.value, len(encoded)]) + encoded)
 
+def send_file_offer(backend, mac):
+	writeall(backend, b'f' + mac)
+
 def handle_user_command(backend, line):
 	global own_nick, own_status
 	global default_target_mac
@@ -290,13 +293,17 @@ def handle_user_command(backend, line):
 				# Set default target of messages
 				default_target_mac = mac_from_name(rest)
 
+			elif command == '/sendfile':
+				# Send an offer to transmit the file
+				send_file_offer(backend, mac_from_name(rest))
+
 			elif command == '/quit':
 				# Quit
 				return 'quit'
 
 			else:
 				# Display usage
-				print('--- / <message>; /msg <target> <message>; /status [<target>]; /peers; /available; /unavailable; /nick [<nick>]; /target <target>; /quit')
+				print('--- / <message>; /msg <target> <message>; /status [<target>]; /peers; /available; /unavailable; /nick [<nick>]; /target <target>; /sendfile <target>; /quit')
 
 		else:
 			# Send message